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Flooding,Flooding, WWaterater andand thethe LandscapeLandscape

Edited by Ian D. Rotherham

Flooding, Water and the Landscape

Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008

Front Cover Picture - © Christine Handley Edited by Ian D. Rotherham

ISSN 1354 - 0262 ISBN 978-1-904098-06-5

Published by: Wildtrack Publishing, Venture House, 105 Arundel Street, Sheffield, S1 2NT

Typeset and processed by: Diane Harrison and Christine Handley

Printed by: B&B Press (Parkgate) Rotherham

Supported by: Biodiversity and Landscape History Research Institute, Hallam Environmental Consultants Ltd, Tourism Leisure and Environmental Change Research Unit at Sheffield Hallam University.

© Wildtrack Publishing and the individual authors All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage or retrieval system, without permission in writing from the publisher. Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008

Preface Ian D. Rotherham Sheffield Hallam University

With floods, water, landscape and climate what’s next? The landmark conference has given us a unique opportunity to find out. The Sheffield Hallam University conference is about issues that will affect us all for years to come. Flooding has already cost millions of pounds in 2007 alone, but it will cost billions over the next few decades. With rapid climate change and other issues, this is a critical matter for everyone. Yet many people still do not understand the problems, and often those most at risk, and even key decision-makers, have little real knowledge of causes or likely scenarios. This event makes the latest information and views of the most senior researchers in Europe and the UK open to all. This event brings together leading practitioners from across the UK and Europe, to discuss one of the most pressing environmental, social and economic issues affecting Britain today – flooding and both climate-induced and landscape-change related flood risks. The problems are increasingly severe and now agencies, politicians and other stakeholders have to make key decisions for long-term planning. This event is especially important in that it presents a diversity of experts and practitioners with a wealth of experience in different disciplines. Indeed, only by such a multi-disciplinary approach can long-term solutions be found. The meeting addresses critical issues of engineering and flood defence, but also landscape-scale responses necessary to minimise wider risk. However, the conference will has presentations on the theoretical and scientific underpinning of the problem and hence the responses. There is much for the urban specialist but also for those interested or involved in the wider landscape too. For landscape managers, woodland and tree managers, engineering and environmental consultants, farmers and landowners, developers and politicians, these are important issues that will influence and affect future portfolios of work. They will also influence professional judgement and advice. The proceedings here are the pre-published papers. However, because of the short time available to organise this important event, some papers did not make the deadline for inclusion. There will be a further volume of post-conference papers available after the conference. There are some critical issues to be considered: 1. Do we know the problems and their causes? The answer is largely yes we do, and they are a combination of climate change, landscape change and management, development on floodplains but the type and intensity of developments in the wider landscape too, and agri- farming and agri-forestry.

2. Are the events of 2007 likely to occur again? The answer is yes and they are likely to get even more extreme.

3. Are we able to predict where and when problems might arise? The answer is that we know where the key ‘pinch-points’ are in the system, but the extreme weather is extremely unpredictable. With flood and drought flip sides of the same issue, who knows where or when the next inundation will occur.

4. Are we taking action to address the problems and to make homes and workplaces, and the wider environment safer? The answer is that there is a lot of research into the issues and considerable investment in flood defence and infrastructure. But this only solves a part of the Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008

problem – really the ‘sticking plaster approach’ of dealing with the symptoms but not the underlying causes. The conference will address these fundamental shifts in the ways that we manage our landscape and our towns. We need to be genuinely more sustainable.

5. Are there any other issues that are not yet being considered? Answer yes. Research at Sheffield Hallam University has shown that extreme floods can release dangerous pollution locked up in valley-bottom sediments from centuries of heavy industry. In some parts of the country such as South and West Yorkshire this may mean heavy metals and other pollutants released from deposits to be spread far and wide across floodlands downstream. These could be farming or housing lands and clearly raises concerns.

Another unexpected impact is that in some areas the erosion caused by severe flooding is washing away archaeology. Centuries old heritage can be swept away overnight.

The final, and very worrying impact again not yet addressed by the responsible agencies or local authorities, is the expected dramatic spread on invasive alien plants such as Japanese Knotweed. From extensive beds of highly invasive Knotweed along urban rivers and on contaminated post-industrial sites, huge amounts of viable plant material will have been spread across the flooded landscapes. In decades to come, the costs of clearly this up could run into millions of pounds. So far there is no strategy for assessment, monitoring or control.

6. Who does this affect? The answer is everyone. Many live or work in areas that are subject to severe flood risk and this will get worse not better. The problems affect people travelling to work or on holiday, they affect farming and food production, and they will have a huge impact on the economy.

7. What can we do? Well everyone can contribute by helping in small ways in homes and gardens across the country. However, the critical decisions will be about how we manage our towns and our countryside, and again this needs to involve the whole community in making sensible and effective decisions. As the conference will hear, there are many positive things that we can do to reduce flood risk and frequency, or at least to limit damage. Some of these can be done quickly such as targeted investment in upgraded infrastructure - flood defences and drainage. However, some of the necessary actions are long-term changes in both development and in countryside management that will take many years to have an effect.

This conference is the first of a series of major stakeholder events on climate and environmental change. These are THE ISSUES OF THE NEXT FEW DECADES so we all need to be better informed, and this information is relevant to local communities, to planners and other decision- makers such as MPs and local councillors. There needs to be communication with all those involved in education from sixth form students and teachers to university students and researchers. It is especially relevant to businesses and others affected by the recent major flood incidents. All these stakeholders need to be engaged in the dialogue now and in the future. Contents Carlos Abrahams All Ebb And Flow - Droughts, Floods and Lakes in the Future Landscape 9 John Ash Flood Risk and Policy Analysis 18 Chris Baines Flooding, Water and The Landscape 26 Jeremy Barrell Urban deforestation; it's here and it's going to hurt! 30 Bill Blackledge North Cave Beck Catchment Area Project 38 Graham Coultish Farming And Flood Storage 40 J. Diaz Nieto, J. Blanksby, An Urban Catchment Scale Approach for Exploring the use of Brownfield D.N. Lerner & A.J. Saul Redevelopment for Pluvial Flood Risk Management 42 Nigel Dunnett Green Roofs and Urban Hydrology 44 Iain Edmonds Engineering and Flood Management 51 Chris Gerrard Mere We Go Again 54 Anna Hall Policy and Farming Perspectives of Flooding and Flood Risk 58 H. Heilmeier, E. Richert, The Integration of Nature Conservation and Flood Prevention Measures in a S. Bianchin, Merta & C. Mountainous Region 60 Seidler H. High, J. Cooper, O. Developing Decision Support for the use of Non-Structural Responses in Flood Grant & K. House Risk Management 71 S.N. Lane Slowing the Floods in the U.K. Pennine Uplands…A Case of Waiting for Godot? 75 David Lerner and Tom Ursula Has Three Eyes - Developing Integrated and Innovative Interventions For Wild Urban River Corridors 92 Steve Maslen Community Engagement in Large Scale Landscape Change Associated with new Approaches to Flood Risk Management 96 David Murphy Strategy and Policy Context of Flood Risk 99 T.R. Nisbet, H. Thomas & Trees and Water - a Forestry Perspective 100 S. Broadmeadow Fola Ogunyoye Floods and Land Management 103 C. Procter, L. Wilson, S. Risk Assessment Approaches for Pluvial Flooding 107 Anthony & S. Humphries N. Richardson, D. Phillips, Managing Flood Risk and Delivering New Habitat - Experience from the P. Miller & D. Huggett Environment Agency Regional Habitat Creation Programme 110 Carolyn Roberts A Gloucestershire Perspective on the 2007 Summer Flooding 119 Ian D. Rotherham Floods and Water: A Landscape-Scale Response 128 Ian D. Rotherham Landscape, Water and History 138 R.J.Smithers, I.R. Calder, Woodland Actions for Biodiversity and their role in Water Management 153 J. Harrison & T.R. Nisbet Rob Stoneman The Summer 2007 Floods - A Plea for Land Management Based Flood Risk Solutions 168 J.L. Whitehead Flood Risk and Electricity Companies 173 Lucy Wilson et al Impacts of 2007 Summer Floods on Agriculture 178 Peter Worrall Sustainable Catchment Management Programme (Scamp) - Landscape Change and Flood Management 182

Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008

All Ebb And Flow - Droughts, Floods And Lakes In The Future Landscape Carlos Abrahams Baker Shepherd Gillespie, [email protected]

Introduction increased slightly in winter and decreased in summer. In addition, heavy precipitation events This paper diverges from the main theme of the have increased in winter throughout the UK conference on two fronts. Firstly, it is not over the past forty-five years. Finally, the primarily concerned with rivers and streams, frequency of drought episodes in England and but rather with the lentic landscape of Wales shows no clear trend over the period floodplains - ponds, lakes and reservoirs - that 1776-2006. Clearly, although understanding of connects with and surrounds river corridors. climate change impacts has developed Secondly, it deals with drought as well as flood. significantly in recent years, there is still Climate change is expected to cause, on the one considerable uncertainty in relation to impacts hand, more frequent and extreme flooding on hydrology and freshwater ecosystems. For events, while on the other, increasing the example, although most climate models predict potential for summer water shortages as a result drier summers and wetter winters in the UK, of reduced summer rainfall and increased detailed predictions of impacts on river flow evapotranspiration. This will stretch the regimes vary, with regional and local variations hydrological 'envelope' in opposite directions, in outcomes. At the UK level, overall flood producing more dynamic hydrological magnitude and frequency in the future may conditions, which are both increasingly well be similar to current conditions (Mitchell unstable and unpredictable. Lakes, reservoirs et al., 2007). and ponds form a highly valuable part of riparian and floodplain landscape diversity However, under many scenarios, annual along river systems. A study by Williams et al. average streamflows are expected to increase in (2004) compared river, stream, ditch and pond northern Europe and decrease in southern and biodiversity within an 80 km2 area of lowland central Europe. There will also be changes in British countryside. This showed that ponds relation to snow-melt runoff. In Britain, north- contributed more than the other features to west regions will have higher winter biodiversity at a regional level, supporting precipitation levels and an increased positive considerably more species, more unique species water balance, with wetlands having to adapt to and more scarce species than other waterbody higher water levels and increased flooding. types. Their conservation within floodplains is Less summer rain and greater therefore of great importance, and the impacts evapotranspiration rates in the south-east will of hydrological changes on them should be produce a net decrease, which will cause more investigated in more detail. frequent and severe low flows and summer droughts (Mitchell et al., 2007). In effect, there Hydrological impacts of climate will be more water available in the landscape in change winter and less in summer (Dawson et al., The latest analysis of trends, from the first of 2001; Estrela et al., 2001). the UKCIP2008 reports (Jenkins et al., 2007), gives an overview of historical climate patterns. This states that annual mean precipitation for England and Wales has not changed significantly since 1766, but rainfall has

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Ecological impacts of hydroperiod A Ramsar Convention report (van Dam et changes al., 2002), states that "it appears that climate change will have its most pronounced effect on The seasonal pattern of water levels in a wetlands through alterations in hydrological wetland forms a distinctive hydrologic regimes: specifically, the nature and variability signature that is termed the hydroperiod of the hydroperiod and the number and severity (Mitsch & Gosselink, 2007). This can be of extreme events". Changes to these will have described in a number of ways, in terms of its: considerable impacts on sites, wildlife • Amplitude - vertical range or depth communities and individual species. One • Duration - of either flooding or drought potential outcome for floodplains could be the events creation of new wetland habitat in the form of temporary pools or riverine wetlands in areas • Seasonality - winter flood, spring flood subject to increased fluvial or pluvial flooding • Direction - flood or drawdown arising from higher winter precipitation. • Rate of change Conversely, many existing wetland features will • Predictability see an increase in the incidence and scale of • Frequency - number of flood/drought events summer drawdown due to reduced summer in a time period rainfall and increased evapotranspiration rates (Dawson et al., 2001). The predicted greater These characteristics are determined by the size propensity for extreme events will produce of the wetland, catchment area and topography, dramatic changes between these two states, source of water supply, climatic factors and with habitats switching more frequently underlying geology. In addition, management between inundated and terrestrial conditions. of water levels can either artificially stabilise or increase natural regimes (Thornton et al., Although there is only a small body of work 1990). addressing the impacts of climate change on wetland vegetation (Dawson et al., 2001), two Every wetland will develop an ecological recent studies have investigated the possible community that is determined by its effects on lakes. Mooij et al. (2005) concluded hydroperiod, alongside other determining that climate change could reduce the numbers factors such as climate, land management and of conservation target species in lakes, benefit water chemistry. However, it is the hydroperiod invasive species, cause a switch from clear- of a wetland that is THE key factor in water macrophyte-dominated lakes to determining its ecology (Keddy, 2000; Mitsch phytoplankton-dominated communities, and & Gosselink, 2007; Weller, 1999). Due to the produce an overall loss of biodiversity. Looking increased seasonal variability in hydrological more directly at impacts on water levels and the regimes, the influence of climate change is inundation period, studies of prairie potholes in likely to have significant impacts on the the USA (e.g. Poiani & Johnson, 2003 (quoted magnitude, timing and variability of the in van der Valk, 2006) and Johnson et al., hydroperiod of waterbodies and the frequency 2004) indicate that water levels would be much and nature of extreme flood or drought events lower under climate change scenarios, with (Arnell, 1999; Eisenreich, 2005; Kundzewicz et some lakes being without standing water for al., 2002; Schindler, 2001). As a result, Poff et long periods of time. Major changes to al., (2002) [quoted in Mitchell et al., 2007] vegetation would be likely to result, with recommend using the hydroperiod as the best consequent impacts for other wildlife such as way to consider the impact of climate change waterfowl. Other studies also indicate that on wetlands. It is therefore a central concept changes could impact on other biological that should be steering our approach to this receptors, including phytoplankton (Nõges et issue. al., 2003), amphibian populations (Brooks, 2004) and aquatic invertebrates (Pyke, 2005).

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Despite what is stated above, the importance terrestrialization but can also provide of the hydroperiod and water levels do not yet regeneration niches that favour the recruitment seem to be recognised within the UK to the of introduced plant propagules. (Amoros & extent that they should be. For example, these Bornette, 1999). characteristics are excluded from the following list in Mitchell et al. (2007), which states that: Direct surface flows in lowland river systems have been shown to have a Climate change will affect the functioning of homogenising effect on the ecology of the rivers, lakes, pools and wetland habitats by floodplain, allowing and causing the spread of affecting river flows, carbon fluxes, nitrogen fish, invertebrates and plant propagules mineralisation and denitrification, throughout the flooded area (Thomaz et al., precipitation, water temperatures, chemical 2007). The hydraulic forces caused to quality, water stratification, oxygen supply, vegetation, can however, cause plants to be ground water recharge, flooding regimes uprooted and washed away, creating and evaporation. disturbance to the vegetation of connected wetlands, reducing competition, promoting The effects of floods and droughts on plant diversity and resetting successional floodplain lakes sequences (Amoros & Bornette, 1999; Ward et Fluvial action, sometimes powerfully exercised al., 2002). through flood events, is the main agent of Gruberts et al., (2007) investigated 24 riverine landscape formation, sustaining floodplain lakes and reservoirs in order to floodplain diversity through a natural reveal the possible impact of the long-term disturbance regime comprising erosion, mean annual flooding frequency on their transport and deposition,. A variety of lentic plankton and macrophyte communities. A low features can be created by this process, such as similarity was found between plankton oxbow lakes, floodwater pools, dammed assemblages and hydrological groups, tributaries and abandoned channels (Ward et indicating that the flooding frequency was not a al., 2002). More frequent river flooding caused major determinant of summer plankton by climate change will potentially enhance communities of these lakes. However, a these formative processes and also force an significant correlation between the flooding increased hydrological and ecological frequency and several physicochemical and connection between the main channel and its biological parameters was found. Hydrological neighbouring lentic waterbodies. Even without connectivity was found to have a significant fluvial flooding, increased rainfall may increase negative impact on zooplankton species the incidence of rainwater pools within the diversity as well as a positive impact on floodplain, either creating new ephemeral Oligochaeta density. Other biotic parameters ponds or extending the hydroperiod of existing were affected by local factors, such as lake temporary wetland features. morphology, internal loading of nutrients from River flooding can impact on lentic sediments, trophic interactions as well as local waterbodies through a number of complex source of dissolved organic matter. processes. Scouring can occur to the basins of From research such as that described above, waterbodies, changing their morphometry, or it might be expected that the most significant alternatively, flows can introduce nutrients, silt impact of river flows on the ecology of and debris. Eutrophication caused by the input floodplain lakes would be exerted through of nutrients (especially from polluted lowland flooding events, when the river overtops into rivers) can increase phytoplankton development adjacent lentic waterbodies. However, a pair of in floodplain lakes, which reduces water studies undertaken in the Netherlands indicates transparency and impedes the growth of rooted that this may not be the case and that 'flow- plants. Silt inputs may accelerate pulses' below bankfull level should also be

11 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 taken into account (Tockner et al., 2000). The Lake-bottom exposure during prolonged low studies by van Geest et al. (2005a,b) of water stages had an opposite effect, resulting in floodplain lakes along the Lower Rhine found an increased probability of dominance by that, during non-flooded conditions, lake water- submerged vegetation and a decrease of level fluctuations were driven by a hydrological floating-leaved nymphaeid vegetation. connection to the river through groundwater flows. Hence, water-level fluctuations are A number of studies have investigated the largest in lakes close to the main channel in impacts of floods and fluctuating water levels strongly fluctuating sectors of the river and on plankton communities in floodplain lakes. It smallest in isolated lakes. Lake age also has a is understood that increased flooding from major effect on the hydroperiod amplitude. climate change will be of detriment to Older lakes develop a sealed sediment layer of floodplain lakes if the river's water quality is clay and silt that minimises hydrological poor. Van den Brink et al. (1994) studied connection to the river and reduces water level floodplain lakes in order to relate their summer fluctuations. Analysis of the aquatic vegetation plankton communities to the entry of highly composition found that species richness of eutrophic water during flood events. It was floating-leaved and emergent macrophytes was found that lakes with a long annual flood reduced at both small and large water-level duration, and consequent prolonged input of fluctuations, whereas species richness of nutrients, were characterised by plankton taxa submerged macrophytes was reduced at lakes associated with open water, and had poorly with small water-level fluctuations but was developed aquatic vegetation. In contrast, higher in lakes that experienced drawdown. In floodplain lakes with a short annual flood had summary, the aquatic vegetation composition taxa associated with aquatic macrophytes, and was correlated more strongly with lake age and supported well-developed aquatic vegetation. the occurrence of drawdown, than with the As a result, the plankton community in amount of time the river was in flood. This floodplain lakes was found to be clearly related determined the suite of species present within to hydrology, nutrient levels and habitat the lake in terms of their dessication tolerance, characteristics, mainly determined by N and P with tolerant species such as Chara sp. found in input from the main channels during flood young, fluctuating lakes and desiccation- events. Similarly, the input of nutrients from sensitive species such as Nuphar lutea in old, the River Paraná into neighbouring lakes was stable lakes. In lakes adjacent to a section of found by de Domitrovic (2003) to produce an river with artificially stabilised water levels, the increase in algal biomass and a shift in lack of drawdown produced species-poor phytoplankton composition. A study by Garcia vegetation that was frequently dominated by de Emiliani (1997) on the same river found that the invasive Elodea nuttallii. floods into a floodplain lake promoted ruderal- strategist phytoplankton species, which then On a landscape scale, the dynamic progressed through an autogenic successional hydroperiods of floodplain lakes cause the sequence during the following isolated phase. number of macrophyte-dominated lakes found As a result of flood events, the lake had in a floodplain to vary between years, frequent changes in phytoplankton composition, depending on water level fluctuations. Coops & biomass, species diversity, evenness and van Geest (2005) reanalysed aquatic-vegetation community change rate. In addition to this inventories made over five decades in potential for interactions between flooding and floodplain lakes along the Lower Rhine, and nutrient inputs, analysis of the crustacean related them to summer inundation and zooplankton of 29 ponds surrounding a flood- drawdown events. Substantial submerged control reservoir revealed that hydroperiod and macrophyte cover (>20 % lake area) was less flood frequency themselves were significant likely after inundation in summer, with contrasting responses for different species.

12 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 factors structuring communities and is likely to cause changes to the typical determining species richness (Medley & Havel, functional characteristics of species present in 2007). those systems, similar to those seen in some regulated lakes, where structurally diverse and Drawdown events in lakes, caused by species-rich plant communities are lost, to be drought conditions, have a major influence on replaced with only a limited suite of ruderal, the community structure of waterbodies and rosette and mat-forming species, often their fringing wetlands (Keddy, 2000). An including more exotics (Hill et al., 1998; increased frequency and duration of low water Rorslett, 1989; Smith et al., 1997; Wilcox & levels produced by climate change, would be Meeker, 1991). This is a result of a shift expected to affect wildlife, waterfowl and fish occurring in plant attributes, from resilience- habitats, water quality, wetland area and type traits (i.e. turions, very small body size vegetation diversity in such ecosystems and free-floating growth forms), which are (Mortsch, 1998). This pressure could be exerted adapted to spatially simple habitats that are simply through the number or area of ponds, rarely disturbed, towards resistance-type traits drawdown habitats or other wetland features (related to stream lining, flexibility and existing within the landscape, or in a more anchorage) that are more appropriate to complicated fashion through impacts on spatially and temporally heterogenous habitats. substrate, colonisation, germination, This would occur together with a trend from competitive interactions between species, and competitive species, to ruderal and desiccation other successional processes which may have a resistance traits more well-adapted to critical impact upon the structure, function and fluctuating habitats (Abrahams, in press; Willby biodiversity interest of wetland communities et al., 2000). To support this hypothesis, (Hulme, 2005, van Dam et al., 2002). Clement & Aidoud (2004) provided modelling Key factors determining species composition evidence that water level changes would have on lake shorelines are the timing, frequency and significant impacts on the vegetation length of drawdown events, with the growing communities of lakes and reservoirs, perhaps period between disturbance events being entailing the replacement of existing perennial critical for plant growth (Meeks, 1969; Nilsson, vegetation communities with annual species 1981). Climate change is likely to cause a and causing the loss of important isoetid transition in lake and pond hydrology from a communities. current state that has long flooded periods with Maltchik et al. (2007) analysed macrophyte short-term drawdowns only in unusually dry assemblages under flooding of brief duration years, towards future conditions that cause (less than 3 days) and drawdown events in a shorter flooded periods, with increasingly floodplain palustrine wetland. Macrophyte frequent drawdowns of longer duration. This species richness was higher during the altered regime will be less suitable for the drawdown phase than during the wet phase. development of submerged aquatic species, as Although macrophyte richness was not increased drawdown will reduce their cover and modified after the three short flooding events, promote the development of vegetation adapted biomass was modified by repeated flooding. to exposed substrates, such as ruderal mudflat Although the intermediate disturbance annuals, grasses and sedges (Gerritsen & hypothesis would appear to be applicable to Greening, 1989; Meeks, 1969; Schneider, riverine floodplains, flooding causes a number 1994). of complex ecological responses that do not Impacts on disturbance regimes allow a simple evaluation of the effects on aquatic plant diversity. There are several The increasing frequency and magnitude of interacting factors that complicate the issue, floods and droughts brought about by climate including waterbody morphometry, change will produce more regular disturbance (sensu Grime, 1979) in floodplain habitats. This

13 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 groundwater connectivity, nutrient levels and floodplain lakes along large lowland rivers. The differential species responses (Amoros & water-level regime of such lakes can in part be Bornette, 1999; Ward et al., 2002). designed, through choice of the location along the river, the distance away from the river and Climate change, adaptation and the the depth profile of the lake. future lentic landscape Where floodplain lakes have suffered a Given the potential for changes in floodplain decline in habitat or species diversity through lakes arsing from climate change, how should artificial stabilisation of lake levels in the past, we prepare for the future? What adaptation can it is possible that climate change induced be put in place to allow adverse effects to be fluctuations could reverse these adverse mitigated? Firstly, understanding the impacts and restore biodiversity interest (Hill et importance of hydrology to wetlands in al., 1998; Wilcox & Meeker, 1991; Van Geest, managed floodplains is key to enabling 2005a). Lakes that have become dominated by managers to gauge the effects of their activities extensive stands of dominant or invasive on regional ecology (Medley & Havel, 2007). species could, with increased water level This understanding must incorporate the fluctuations, develop a wider species hydroperiod and an acknowledgement of the complement through the creation of niches for importance of water levels. The impact of flood a more diverse range of less competitive events may currently form the dominant species. This could potentially result in paradigm in our thinking but droughts and river increased spatial and temporal availability of flow-pulses below flood level need to feature habitat for scarce and rare plants such as six- equally in our assessments. The processes stamened waterwort Elatine hexandra, thread linking water level fluctuations and lake rush Juncus filiformis, mudwort Limosella ecosystems, and how these relate to climate aquatica and tasteless water-pepper Persicaria change is a key research issue that needs to be mitis (Abrahams, 2005). addressed in order to understand the possible composition of future communities and to The increasingly dynamic floodplain develop suitable adaptive strategies to cope landscape will undoubtedly prove interesting to with climate change impacts (Abrahams, 2007; ecologists, worrying to homeowners, Dawson et al., 2001). troublesome for the water industry and expensive to insurers. To help us understand Land use priorities may need to change. and manage the process as conservationists, we There may need to be a re-evaluation of need to translate ecological studies from other floodplain management in a similar way to that countries to the UK context. We also need to we have seen on our coasts, where there has promote some home-grown research into been a conceptual move away from traditional climate change and water levels and convert sea-defences towards coastal realignment. this into practical adaptation guidance. Increased flood risk in some areas may likewise prompt a retreat from the floodplain in coming In our highly-regulated floodplain landscape years. This could provide opportunities for it is conceivable that the hydrological impacts nature conservation in areas set aside for flood of climate change could be good for wildlife. In management, either in the creation of new some instances, they could effect a re-wilding washlands or balancing lakes. Van Geest et al. of the floodplain, imposing natural events that (2005b) suggest that excavation of new lakes is are outside our control. However, there is still a essential to conserve the successional sequence high level of uncertainty to climate change of floodplain water bodies and maintain predictions and how any altered hydrological conditions of high biodiversity. Shallow, regimes will interact with our flood and water moderately isolated, lakes with occasional resource management operations. It would be substrate exposure through drawdown have the highest potential for creating macrophyte-rich

14 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 prudent to make room for such changes in Dawson, T.P., Berry, P.M. & Kampa, E. (2001) conservation strategies, River Basin Impacts on freshwater environments. In: Management Plans and individual site plans. Harrison, P.A., Berry, P.M. &. Dawson, T.P (Eds.) Climate Change and Nature To conclude in simplistic terms, we should Conservation in Britain and Ireland. UKCIP remember that species-rich diverse ecosystems, Technical Report, Oxford. including floodplains, are formed and maintained by natural processes, which produce de Domitrovic, Y.Z. (2003) Effect of a necessary disturbance regime. Wetlands such fluctuations in water level on phytoplankton as floodplain lakes can benefit from both development in three lakes of the Paraná river drought and flood. Whether climate change will floodplain (Argentina). Hydrobiologia, 510(1- produce an intermediate level of disturbance to 3), 175-193. these systems and promote diversity though, or provide too much of a good thing, remains to Eisenreich, S.J. (Ed.) (2005) Climate Change be seen. and the European Water Dimension. European Commission - Joint Research Centre, Ispra. References Estrela, T. et al. (2001) Sustainable water use Abrahams, C. (2005) The ecology and in Europe. Part 3: Extreme hydrological events: management of drawdown zones. British floods and droughts. European Environment Wildlife, 16, 395-402. Agency. Abrahams, C. (2007) Lakes, water levels and García de Emiliani, M.O. (1997) Effects of climate change. ECOS, 28(3/4), 40-45. water level fluctuations on phytoplankton in a river-floodplain lake system (Paraná River, Abrahams, C. (in press) Climate change and Argentina). Hydrobiologia, 357(1-3). lakeshore conservation: a model and review of management techniques. Hydrobiologia. Gerritsen, J. & Greening, H.S. (1989) Marsh seedbanks of the Okefenokee swamp: Effects of Amoros, C. & Bornette, G. (1999) Antagonistic hydrologic regime and nutrients. Ecology, 70, and cumulative effects of connectivity: a 750-763. predictive model based on aquatic vegetation in riverine wetlands. Archiv für Hydrobiologie, Grime, J.P. (1979) Plant Strategies and 115(Supplement), 311-327. Vegetation Processes. Wiley. Arnell, N.W. (1999) The effect of climate Gruberts, D., Druvietis, I. Parele, E. Paidere, J., change on hydrological regimes in Europe: a Poppels, A. Prieditis, J. & Skute, A. (2007) continental perspective. Global Environmental Impact of hydrology on aquatic communities of Change, 9, 5-23. floodplain lakes along the Daugava River (Latvia). Hydrobiologia, 584(1), 223-237. Brooks, R.T. (2004) Weather-related effects on woodland vernal pool hydrology and Hill, N.M., Keddy, P.A. & Wisheu, I.C. (1998) hydroperiod. Wetlands, 24(1), 104-114. A hydrological model for predicting the effects of dams on the shoreline vegetation of lakes Clement, B. & Aidoud, A. (2004) Euro-limpacs and reservoirs. Environmental Management, 22, Deliverable No. 51. Report describing 723-736. specification of a model predicting changes in CORINE/EUNIS communities under climate Hulme, P.E. (2005) Adapting to climate change: change WP1. is there scope for ecological management in the face of a global threat? Journal of Applied Coops, H. & Van Geest, G.J. (2005) Extreme Ecology, 42, 784-794. water-level fluctuations determine aquatic vegetation in modified large-river floodplains. Archiv für Hydrobiologie, 15(1-4), 261-274.

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Jenkins, G.J., Perry, M.C. & Prior, M.J.O. Nõges, T., Nõges, P. & Laugaste, R. (2003) (2007) The climate of the United Kingdom and Water level as the mediator between climate recent trends. Met Office Hadley Centre, UK. change and phytoplankton composition in a large shallow temperate lake. Hydrobiologia, Johnson, W.C., Boettcher, S.E., Poiani, K.A. & 506, 257-263. Guntenspergen, G.R. (2004) Influence of weather extremes on the water levels of Pyke, C.R. (2005) Interactions between habitat glaciated prairie wetlands. Wetlands, 24(2), loss and climate change: implications of fairy 385-398. shrimp in the Central Valley Ecoregion of California, USA. Climatic Change, 68, 199- Keddy, P.A. (2000) Wetland Ecology: 218. Principles and Conservation. Cambridge University Press. Rorslett, B. (1989) An integrated approach to hydropower impact assessment. Hydrobiologia, Kundzewicz, Z.W., Budhakooncharoen, S., 175,65-82. Bronstert, A., Hoff, H., Lettenmaier, D., Menzel, L. & Schulze, R. (2002) Coping with Schindler, D.W. (2001) The cumulative effects variability and change. Floods and droughts. of climate warming and other human stresses Natural Resources Forum, 26, 263-274. on Canadian freshwaters in the new millennium. Canadian Journal of Fisheries and Maltchik, L., Rolon, A.S. & Schott, P. (2007) Aquatic Sciences, 58, 18-29. Effects of hydrological variation on the aquatic plant community in a floodplain palustrine Schneider, R. (1994) The role of hydrologic wetland of southern Brazil. Journal of regime in maintaining rare plant communities Limnology, 8(1), 23-28. of New York's coastal plain pondshores. Biological Conservation, 68, 253-260. Medley, K.A. & Havel, J.E. (2007) Hydrology and local environmental factors influencing Smith, B.D., Maitland, P.S. & Pennock, S. zooplankton communities in floodplain ponds. (1987) A comparative study of water level Wetlands, 27(4), 864-872. regimes and littoral benthic communities in Scottish lochs. Biological Conservation, 39, Meeks, R.L. (1969) The effect of drawdown 291-316. date on wetland plant succession. Journal of Wildlife Management, 334, 817-821. Thomaz, S.M., Bini, L.M. & Bozelli, R.L. (2007) Floods increase similarity among Mitchell, R.J. et al. (2007) England aquatic habitats in river-floodplain systems. Biodiversity Strategy - Towards Adaptation to Hydrobiologia, 579(1), 1-13. Climate Change. Defra. Thornton, K.W., Kimmel, B.L. & Payne, F.E. Mitsch, W.J. & Gosselink, J.G. (2007) (Eds.) (1990) Reservoir Limnology: Ecological Wetlands. Wiley. Perspectives. John Wiley & Sons. Mooij, W. et al. (2005) The impact of climate Tockner, K., Malard, F. & Ward, J.V. (2000) An change on lakes in the Netherlands: a review. extension of the floodpulse concept. Aquatic Ecology, 39, 381-400. Hydrological Processes, 14(16-17), 2861-2883. Mortsch, L.D. (1998) Assessing the impact of van Dam, R., Gitay, H. & Finlayson, M. (2002) climate change on the Great Lakes shoreline Climate Change and Wetlands: Impacts, wetlands. Climatic Change, 40, 391-416. Adaptation and Mitigation. Ramsar COP8 Nilsson, C. (1981) Dynamics of the shore DOC. 11, Information Paper. Ramsar vegetation of a North Swedish hydro-electric Convention Bureau. reservoir during a 5-year period. Acta Phytogeographica Suecica, 69.

16 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 van den Brink, F.W.B., Van Katwijk, M.M. & Van der Velde, G. (1994) Impact of hydrology on phyto- and zooplankton community composition in floodplain lakes along the Lower Rhine and Meuse. Journal of Plankton Research, 16(4), 351-373. van der Valk, A.G. (2006) The Biology of Freshwater Wetlands. Oxford University Press. van Geest, G.J., Coops, H., Roijackers, R.M.M., Buijse, A.D. & Scheffer M. (2005a) Succession of aquatic vegetation driven by reduced water- level fluctuations in floodplain lakes. Journal of Applied Ecology, 42(2), 251-260. van Geest, G.J., Wolters, H., Roozen, F.C.J.M., Coops, H., Roijackers, R.M.M., Buijse, A.D. & Scheffer, M. (2005b) Water-level fluctuations affect macrophyte richness in floodplain lakes. Hydrobiologia, 539(1), 239-248. Ward, J.V., Tockner, K., Arscott, D.B. & Claret, C. (2002) Riverine landscape diversity. Freshwater Biology, 47, 517-539. Weller, M.W. (1999) Wetland Birds. Cambridge University Press. Wilcox, D.A. & Meeker, J.E. (1991) Disturbance effects on aquatic vegetation in regulated and unregulated lakes in northern Minnesota. Canadian Journal of Botany, 69, 1542-1551. Willby, N.J., Abernethy, V.J. & Demars, B.O.L. (2000) Attribute-based classification of European hydrophytes and its relationship to habitat utilization. Freshwater Biology, 43(1), 43-74. Williams, P., Whitfield, M., Biggs, J., Bray, S., Fox, G., Nicolet, P. and Sear, D.A. (2004) Comparative biodiversity of rivers, streams, ditches and ponds in an agricultural landscape in Southern England. Biological Conservation, 115(2), 329-341.

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Flood Risk And Policy Analysis John Ash Technical Director Risk & Policy Analysts Ltd

Introduction tax farmers on the Nile flood plain. The greater Flood events, either from the sea or rivers, are the flood, the more silt deposited and the higher regular news items not just in this country but the tax. worldwide. They do not stay newsworthy for In England there is evidence of the Romans long but the effects of flooding for those building earth banks to protect areas from the immediately affected can last for months and sea and some, such as those in King’s Lynn, are years, either through being homeless as damage still in use, although now as secondary is repaired or effects on health. There are also defences. The Romans also saw the possibility effects on a wider population through disrupted of East Anglia and in particular the Fens for travel, effects on infrastructure such as sewage agriculture and built embankments to help treatment and water supply and on business reclaim land. The cost may have been high in activities. Following each flood there is usually terms of slave labour as the Roman writer a public outcry for more to be done and often it Tacitus records, ‘Britons complained that the appears that government responds. Romans wore out and consumed their bodies Flood Risk Management Policy is the and hands in clearing woods and embanking responsibility of Central Government with the fens’. Defra as the lead department. The The later Saxons had neither the engineering implementation of that policy is the ideas nor skill of the Romans and the protected responsibility of primarily the Environment areas in the Fens reverted to their previous state Agency but also to a lesser degree, local and eventually…‘became a resort for outlaws authorities and Internal Drainage Boards. and other undesirables; a veritable no-mans The summer floods of 2007 demonstrated land’. flooding from high intensity rainfall events Disastrous floods are recorded in East overwhelming sewers and leading to flooding Anglia in 1236, 1260 and 1287, with many of many thousands of properties. The lives lost. This period appears to be linked to responsibility for sewers lies with water sea level rising and an increase in storminess. companies and the flooding raised questions of John of Oxnead describes the flood from the overall responsibility for flooding. sea in 1286 as follows: ‘The sea in dense This paper will look at how flood risk darkness began to be agitated by the violence management policy has developed over the of the wind and burst through its accustomed years and whether it has been effective or if limits, occupying towns, fields and inundating changes are needed. parts which no age in past times had recorded to have been covered in sea water. For, issuing The Historic Context forth about the middle of the night, it suffocated or drowned men and women sleeping in their Flood risk management is not recent. The beds, with infants in their cradles, and many Egyptians used a sophisticated flood warning kinds of cattle. Many were surrounded by the and flood management policy to not only waters, sought a place of refuge by mounting predict flood levels, but also used the data to into trees, but, benumbed by the cold, they fell in and were drowned.’

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The defence of land against flooding and The brief of this 1927 Royal Commission was actions taken to improve drainage of land have to consider the administration of land drainage been an integral part of coastal land and consider if an amendment of the law was management for hundreds of years. Initially needed to secure an efficient system of such actions were used to maximise agricultural drainage. The conclusions were far reaching production (grazing and arable) on fertile land and stated, ‘It will be apparent from the which was also close to transport routes of foregoing summary that the administration of rivers or the sea. The provision of defences was the arterial drainage is conducted by a initially carried out by local landowners very confused tangle of authorities, established by much on a ‘piecemeal’ basis with areas of land the piecemeal legislation of 500 years and not just protected from the sea but also exercising a great variety of powers and reclaimed. functions. There is no uniformity of method of powers or of liability, many drainage Over the years, the Government gradually authorities are doing admirable work, others took an interest in flooding and land drainage are doing none. The efforts of some authorities issues as it was seen as a benefit to the nation. are rendered ineffective by the lack of co- The earliest Crown authority for flood operation of their neighbours and by the fact defence/land drainage purposes was the that the drainage of adjoining land is under no appointment of the Lords, bailiffs and jurats of control whatever. Liability for works is the Romney Marsh in the early thirteenth regulated by no common or uniform system and century. In 1427, Henry VI appointed is frequently obsolete and obscure’. As a result Commissioners of Sewers (for a period of ten the 1930 Land Drainage Act was passed, years) who were sent to all parts of the realm repealing all previous Acts. The Act established with powers to survey sea defences and flood Catchment Boards who derived income from alleviation in rivers, to maintain and repair not just those who benefited directly, but also those flood defences and take action against by precepting other authorities, primarily the people who might damage the defences. They County Councils and Drainage Boards (if they were also given powers to levy rates for any existed in their area) (Purnell, 1993). payment or expenses occurred (Purnell, 1993). One conclusion of the 1927 Royal These commissions became more or less Commission is of particular permanent under the Bill of 1531 which interest,‘…originally the lowlands were in provided that Commissioners of Sewers could many cases swamps, receptacles for upland be set up at any time and without limit to their waters. The ingenuity of the low lander has jurisdiction. Many of these commissions reclaimed them and from being vast unhealthy existed up until the time of the 1927 Royal wastes, they have in many instances been Commission (Purnell, 1993). converted into some of the richest and most In parallel with the establishment of the valuable land in the kingdom’. (Defra’s Chief Commissioners of Sewers, a large number of Engineer commented in a paper on Flood drainage authorities were set up primarily as a Alleviation in 1993, ‘These days there are response to the agricultural reform. The most many who will dispute whether these converted famous is perhaps the Conservators of the unhealthy wastelands are more valuable than Great Level of the Fens (the Bedford Level the ecologically rich swamps that previously Corporation) set up by Act of Parliament in existed’.) 1661 to control the large area of the fens which The River Board Act of 1948 made had been previously reclaimed. considerable changes to the Land Drainage Act, In the 1920s it was recognised that the UK which up to that time was primarily for the was not producing enough foodstuffs and in maintenance and improvement of drainage and 1927 Lord Bledisloe was appointed to inquire flood defences for the benefits of agricultural into the present law relating to land drainage. production. Catchment Boards were superseded

19 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 by River Boards, which covered the whole of was the result of sporadic and ill-considered the catchment of all major rivers and gave development near the coast which has led to powers for fisheries and pollution control unnecessary expense both in the way of (Purnell, 1993). payments from the Lord Mayor’s fund and by way of additional expenditure on restoration The devastating floods of 1947 and 1953 and improvement. The machinery for graphically demonstrated the reliance of low preventing such development already exists lying land on effective defences to reduce under the Town and Country planning Act flooding and hence the loss of agricultural 1947. We think that all possible steps should be production and loss of life. taken to prevent further undesirable The Report of the Departmental Committee development and that full use of the machinery on Coastal Flooding (The Waverley Report), of the Planning Act should be made.’ dated May 1954, appears to be the first In Section 46, where appropriate standards reference to standards of defence. Section 11 are discussed, the need to consider the value of states that, ‘…the maximum standard of the defended area is discussed. However it also protection to be afforded by public authorities states that, ‘…we do not exclude the possibility against flooding should in general be that of a lower standard but in some places where sufficient to withstand the flood of January this might have been appropriate, people living 1953, and this should be provided where under the protection of defences existing before flooding would affect large areas of the flood have developed their property with agricultural land, or would lead to serious those defences in view, and we think that to damage to property of high value such as avoid any breach of public faith those defences valuable industrial premises or compact should, where practicable, be restored and residential areas. Elsewhere, the defences maintained.’ should be at a standard which would reasonably have been thought adequate before Since the 1948 Act, the subsequent Land the flood of January 1953. In certain Drainage Acts, Water Resource Acts and Water circumstances, higher and lower standards may Acts, whilst not changing the essence of the be appropriate. Anyone requiring such a high original Act, added powers and responsibilities standard should pay for it himself.’ to change the emphasis from the protection of agricultural land towards the need to protect The guidance given on standards of property and life and the environment. protection by the Waverley Report were generally implemented, especially on the East Throughout the Land Drainage Acts there and South Coasts during the 1950s and 1960s, has remained one important thread. The power with tidal defences being raised and to undertake flood alleviation works is strengthened to a nominal 1 in 100 year permissive, i.e. no statutory right to be standard (the estimated return period of the protected against flooding exists. It is the 1953 flood). The exception to this was the responsibility of the operating authority (now London tidal defences which provide protection the Environment Agency) to decide which to the capital against a 1 in 1000 year event projects should be promoted, but within (Waverley et al., 1954). Treasury guidelines and financial constraints. The Waverley Report also commented on the Floods and Flood Risk management need not to build in flood plains and look Policy carefully at defending those properties which had previously enjoyed protection. Flood Risk Management Policy is the responsibility of Defra (Department for Section 74 of the Waverley Report states Agriculture, Food and Rural Affairs) as the that, ‘We have been impressed by the fact that successor body of MAFF (Ministry of much of the damage done by the 1953 floods

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Agriculture, Fisheries and Food) and previous the floods. The estimated annual probabilities to that MAF (Ministry of Agriculture and of the worst affected areas were between 1 in Fisheries). 75 and 1 in 170 (Bye & Horner, 1998). In 1993 MAFF published a Strategy for The recommendations of the independent Flood and Coastal Defence in England and review team were wide ranging including the Wales (MAFF, 1993). This clearly set out the need for: strategy to deliver the Government’s Flood and Coastal Defence Policy: ‘To reduce the risks to • a radically modified strategy for improving people and the developed and natural flood warning performance; environment from flooding and coastal erosion • a procedural review to bring about better by encouraging the provision of technically, concerted (emergency) response from all environmentally and economically sound and organisations; and sustainable defence measures’. • a review of organisational, management and investment justification to establish the The Strategy, perhaps for the first time, potential for improving efficiency and clearly set out the Government’s line on effectiveness in the provision, operation and responsibilities, priorities, strategic approaches, maintenance of flood warning and defence. maintenance and management planning, flood warning and emergency procedures, appraisal procedures, monitoring and communication. Severe Floods in Autumn 2000 flooded over The implementation of policy at that time 10,000 properties at 700 locations in England was undertaken by the National Rivers and Wales with widespread disruption to road Authority (through Regional Flood Defence and rail services. That Autumn was described Committees), Local Authorities and Internal as the wettest on record for over 270 years and Drainage Boards. Flood Risk management (or damage amounted to over £1.0 billion land drainage as it was known) passing through (Environment Agency, 2001). a succession of bodies from Catchment Boards The Environment Agency Lessons Learnt to River Boards to River Authorities and finally Report (Environment Agency, 2001) identified to Water Authorities until their privatisation, a number of areas for improvement including: which led to the setting up, for the first time, of a national body: The National Rivers Authority. • the attribution of responsibility for the However, for some water courses the management of watercourses posing a responsibility still lay with the local authorities significant flood risk needs to be reassessed and Internal Drainage Boards. in order to resolve current confusion; • Floodline should be expanded to provide a The Environment Agency was set up under one-stop-shop information service for the Environment Act 1995 bringing together the flooding; responsibilities of the National Rivers Authority • arrangements are needed to assure funding and HMIP (Her Majesty’s Inspectorate of for a strategic 10-year campaign to promote Pollution). The Easter floods of 1998 were a increased flood preparedness across society ‘baptism of fire’ for the new organisation, and vulnerable groups; although for many within the flood risk management field it was only a change of name • an urgent need to put flood emergency as their jobs and responsibilities remained the planning on a sound statutory and financial same. The Easter 1998 floods were described as footing; the worst ever recorded on the Leam, Avon, • Water and Power Utilities, Railtrack and Great Ouse and Cherwell catchments with Highways Agency should carry out flood damages in excess of £350 million and five risk assessments and contingency plans for people dying directly or indirectly as a result of their assets in flood risk areas;

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• Environment Agency to undertake a review The Environment Agency Review to establish ‘best’ working practice, highlighted three areas of policy where action including training needs, to gain maximum is needed by the Government: benefit from this experience; and • Need for a strategic overview of inland • Government should recognise that there is a flooding. Environment Agency should be need for a significant increase in funding for given a clear overview role for urban flood defence on a planned basis as flooding from all sources which would indicated by MAFF’s research. This is provide the framework for local authorities needed to improve flood warnings, secure a and other partners to plan locally and work reasonable condition for present assets and together to manage urban flood risk. improve the overall standard of flood defence. • Measures should be put in place to ensure that key utilities and public services take The Government published ‘making Space for responsibilities for climate change proofing Water’ in 2004 setting out a strategic direction critical infrastructure, facilities and services. of travel for flood and coastal erosion risk management (Defra, 2005). The aim, as set out • Future flood risk management investment in the document, is to, ‘…manage risks by needs to increase so that we can adapt to our employing an integrated portfolio of changing climate. approaches which reflect both national and The Environment Agency also identified three local priorities, so as to: key areas for itself and partners to act: • reduce the threat to people and their • The flood warning service for rivers was property; and mainly effective but warnings were not • deliver the greatest environmental, social provided for rivers that react quickly to rain and economic benefit, consistent with the or properties at risk from surface water Government’s sustainable development flooding. We should examine what broader principles.’ scale warnings about severe weather and potential floods can be provided to professional partners. A wide ranging set of actions were • Need to ensure flood warnings offer clear, programmed and are being, or have been, accurate and timely information which is undertaken to improve risk management, readily accessible. strengthen land use planning process, review best practice and test different approaches for • Multi-agency response plans need to integrated urban drainage management and consider the possible impact on critical develop a more strategic and integrated infrastructure more effectively. approach to managing coastal flooding and The independent review of the 2007 floods is erosion risks. being undertaken by Sir Michael Pitt and the Final Report is due in early 2008, but an The floods in summer 2007 flooded 55,000 interim report in December 2007 highlighted a homes and businesses, eight motorways and led number of areas that required review and to thirteen deaths. The Environment Agency improvement including (Pitt, 2007): carried out an internal review of the floods and concluded that it was the wettest May to July • stronger local leadership of flood risk period in the last 250 years. Surface water management; sewer flooding in Hull flooded over 10,000 • clarification of roles; properties and again raised questions of • more effective co-operation between responsibility. The other significant event was responsible organisations; the flooding of a water treatment works leaving • better protection of infrastructure; and 140,000 homes without water in Gloucestershire (Environment Agency, 2007). • wider and deeper public engagement.

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Another observation by the Pitt Review was the would have, I believe, considerably reduced the effort by very many people who worked development in flood plains. The recent tirelessly during the floods, saving lives and Planning Policy Statement 25: Development doing what they could to help people directly and Flood Risk will reduce development in affected. It stated that there may be questions flood plains but will not help the many about multi-agency states of readiness, but once thousands of properties already at risk of the level of risk became known, all the relevant flooding. organisations acted with considerable force, compassion and effectiveness. Institutional Arrangements The Select Committee on Agriculture Sixth Have we got it Right? Report (Select Committee, 1998) stated that, There are a number of common threads running ‘Even a cursory examination of the existing through the flood events reviews, reports and arrangements for flood and coastal defence lessons learnt. It may be too harsh to say that policy show that a wide range of organisations the lessons learnt do not seem to be acted upon, are involved in its administration, financing as in some areas of policy and flood risk and delivery.’ management there has been progress. This has also been picked up, in the Pitt Flood warning Report (Pitt, 2007), and again brings into the discussions not just flooding from rivers and One such area is flood warning and the sea, but also surface water flooding. The Environment Agency’s Floodline. Many more suggestion from Sheffield University professor people now get warnings and can take action, Richard Ashley is that there are too many although there is a need for ongoing awareness frameworks, and local authorities should take campaigns as floods are soon forgotten except charge as they have the local knowledge and by those who were directly involved. The know local needs. This may have been the case breakdown of the Environment Agency website in the past but most local authorities no longer during flood events is an area that does need have technical departments. One suggestion in addressing. the Pitt Report is understood to include the Defences recommendation to have expert drainage engineers in each local authority. The In all the recent floods defences have not failed Institution of Civil Engineers, in its report in structurally. Flooding has usually been caused 2001 Learning to Live with Rivers (Fleming, by events greater than the defence design event. 2001), identified a skills shortage and this has However, there is a need to ensure all the not improved to date. defences are maintained in good condition for them to be effective. The Public Accounts There are three questions to be asked: Committee reported recently in its Fourth 1) Is the legislation adequate to manage flood Report (Public Accounts Committee, 2006) that risk from a variety of sources? only 46% of high risk defence systems were in target condition. The whole area of asset 2) Is Defra the most appropriate lead management, including funding, therefore government department for flood risk requires attention otherwise past investment management? will have been in vain. 3) Is the Environment Agency the most appropriate authority for flood risk Development Control management? Although it is not helpful to keep referring back to history, it is a pity that the recommendations The answer to all three questions, I believe, is of the Waverley Committee with respect to no, as flood risk management policy and development were not taken seriously. This implementation has not progressed sufficiently

23 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 over the years to the level expected by the Conclusions public. There does need to be a comprehensive The answer to the question of ‘Have we got it review taking into account all the lessons learnt right?’ is yes and no. Yes, progress has been from the floods over the past 10 years and made in some areas but also no, there are still earlier. If we cannot effectively manage floods fundamental concerns with forward planning, now what does the future hold if flooding funding and who is responsible for what. becomes more severe in scale and time? Flooding from rivers and the sea is not a Funding recent phenomena. However, society always Funding for flood risk management has been seems surprised when flooding occurs. We need relatively static over the past 5 years with a to be more proactive than in the past and take small increase in 2005/06 but a reduction in down off the shelves the lessons learnt reports 2006/07. The results of the comprehensive and put the recommendations into practice. The spending review have just been made available observation by the 1927 Royal Commission (February 2008) and this shows an increase, as that, ‘…the administration of the arterial promised by the Minister in 2007, to £506 drainage is conducted by a confused tangle of million in 2007/08, rising to £679 million in authorities, established by the piecemeal 2010/11. This increase is welcome but it legislation of 500 years..’ is as relevant today as remains to be seen if the money can be spent to it was eighty years ago. good effect. The Select Committee on Public This sentiment was reiterated in the Accounts Fourth Report (Public Accounts conclusions of Select Committee on Public Committee, 2007) states that, ‘The Accounts Fourth Report where it stated that, (Environment) Agency could make more ‘The different bodies involved in water effective use of the funding already available to management appeared quick to absolve it: themselves of any responsibility for the floods • through better prioritisation aided by in 2007 and there is little evidence of enhanced management information systems; collaborative working with the (Environment) Agency to minimise the risk of such events’. • by better targeting of resources available based on flood risk in different parts of the country; and Let us hope that we do not have to wait another eighty years before we can implement • by reducing the programme and project an effective flood risk management policy that development costs when constructing reduces the risk to people and the built and defences.’ natural environment. Central government funding is obviously politically driven and historically increases do References seem to be in response to events. The Association of British Insurers (2007) Summer Association of British Insurers Report Summer Floods 2007: Learning the Lessons. London, ABI. Floods: Learning the Lessons (ABI, 2007) calls Bye, P. and Horner, M. (1998) Easter 1998 Floods - for the government to produce a twenty-five Final assessment by the Independent Review Team. year national strategic plan outlining policy and Environment Agency, Bristol. investment needs. This is to be encouraged and Defra (2005) Making space for water - Taking is vital for long term planning but does not sit forward a new government strategy for flood and comfortably with what is generally shorter term coastal erosion risk management in England. Defra government planning. Publications, London. Environment Agency (2007) Review of 2007 summer floods. Environment Agency, Bristol. Environment Agency (2001) Lessons learned - Autumn 2000 floods. Environment Agency, Bristol.

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Fleming, G., Frost, L., Huntington, S., Knight, D., Law, F. and Rickard, C. (2001) Learning to live with rivers. Final report of the Institution of Civil Engineers’ Presidential Commission to review the technical aspects of flood risk management in England and Wales. The Institution of Civil Engineers, London. MAFF and the Welsh Office (1993) Strategy for Flood and Coastal Defence in England and Wales. MAFF Publications, London. Pitt, M. (2007) Learning lessons from the 2007 floods - An independent review by Sir Michael Pitt – Interim Report. Cabinet Office, London. Purnell, R.G. (1993) Flood Defence Legislation and Management. Paper given to UK-Hungarian Workshop – Flood Alleviation 1993, unpublished. Select Committee on Agriculture (1998) Agriculture - Sixth Report. Article downloaded from House of Commons website (http://www.publications.parliament.uk). Select Committee on Public Accounts (2007) Fourth Report. Article downloaded from House of Commons website (http://www.publications.parliament.uk). Waverley, J.V. (1954) Report of the Departmental Committee on Coastal Flooding. HMSO, London.

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Flooding, Water And The Landscape Chris Baines

Introduction mainly deciduous, with a healthy woodland In a country that has always been renowned for floor, then the leaf litter provides a second its wet weather there is now an escalating water management benefit by acting as a frequency of water shortages as well as serious natural sponge, and soaking up the rain. By floods. There is a popular assumption that this contrast, evergreen plantations tend to have conundrum is a consequence of global relatively little absorbency at ground level, and warming. Whist more extreme weather patterns they are made even less water retentive thanks are certainly a factor, it is clear that both to their deep ploughed land drainage systems. shortages and surpluses are influenced far more In lowland river valleys, land which is well by the way that land is being treated. As the vegetated, with a natural drainage system, tends British landscape has increasingly been to be of greatest benefit. The draining and engineered to shed rainwater from the surface, rolling of arable farmland and the intensive use the land has lost its moderating influence on of buried land drains tends to speed the rate at streams and rivers. The reduction in its natural which the water leaves the land, whilst absorbency means that most rainfall will unimproved permanent pasture, with its healthy disappear downstream before it can be captured soil structure, tunnelling worms and penetrating for our future use, and the resulting storm water root runs tends to have great water-holding surge creates far greater risk of flooding when capabilities. Where intensive agricultural it flows through a riverside town or meets a production can make way for natural habitats high tide in a coastal estuary. such as lowland bogs, wet woodland, reed beds and shallow water bodies, then the rural river valley can become a water-holding landscape Beneficial landscape features which will offer significant protection for any Certain elements of the British landscape help urban settlements down stream. to facilitate water retention. Above the tree line, blanket bog and heather moorland both have At the coast, the risk of flooding tends to be great capacity to act as natural reservoirs. The at its greatest when high rivers in spate meet peaty soils and sphagnum moss communities rising tides. Until very recently, coastal flood can retain a great deal of rainwater, and they defence was almost entirely dependent on hard play a vital role in slowly releasing the water engineering - flood protection banks and into upland reservoirs and upper catchment barrages designed to keep the sea at bay. Now streams. When maintained in their waterlogged there is growing recognition that a softer, more condition, these extensive upland landscapes naturally absorbing kind of coastal landscape also serve as carbon sinks, and they provide can serve as a safety valve. Hard defences are important habitat for rare wild species and for being dismantled around the estuaries and remote recreation. along the sinking coast of eastern England. Salt marsh habitat is being restored, and coastal Woodland brings a double benefit. The settlements and wildlife habitats are both canopy of the trees can intercept as much as a benefiting. third of the rainfall, hold it and return it to the air through evaporation. The balance of the rain does drip and trickle to the ground eventually, but the trees slow down the rate of rainstorm impact quite significantly. If the woodland is

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Aggravating influences designed to carry the water out of sight as In the rural countryside there are three main rapidly as possible. The same piped system reasons why the landscape has become more serves the roads, the car parks and the other unabsorbent. The loss of broadleaved woodland hard-paved areas, so a sudden downpour is is the longest-standing of these, and stretches dispersed downstream almost instantly. Even back for thousands of years, although the the millions of domestic gardens that would massive programme of coniferisation, and the once have served as green and leafy soakaways loss of small farm woods throughout the are being paved for parking or for patios, or twentieth century has been significant. being built over as unintended victims of the government’s policy to focus urban Land drainage is the second major factor. regeneration on previously developed When ditches were dug with pick and shovel, “brownfield” land. and clay tiles had to be installed by hand, agricultural land drainage tended to be both Practical remedies modest and relatively inefficient. The post war There is no single magic bullet, but there is one emergence of heavy tractors and seamless overarching policy change that needs to be plastic piping changed all that, and embraced. There is a need to integrate policy consequently there has been a spectacular and practice across entire river catchments, increase in the rate of rainwater run-off. In from the summit to the sea, with the aim of many parts of the country water conservation restoring the natural absorbency and water has been dealt a double blow, with industrial holding capacity of the landscape wherever scale artificial irrigation being used to possible. compensate for the loss of the land’s natural water-holding capacity. In the rural countryside there is great scope for improving the look of the landscape whilst The increased intensity of modern at the same time increasing the mosaic of agricultural methods has been the third major wildlife habitats, increasing the natural rural factor that has made water management productivity of the farmland, restoring the soil’s less sustainable. Agrochemicals have added to stability and boosting the rural economy. There water pollution problems, but they have also is a need to begin managing rural river helped to make the landscape less water- catchments as drinkingwater conservation and retentive. Arable crops are often sown back to flood protection zones, with greater emphasis back, with very little opportunity for soils to on rural recreation, nature conservation and recover their natural structure. The use of high quality food production. Reducing herbicides tends to leave more of the soil drainage in the uplands, increasing broadleaved surface unprotected against rainfall, and the woodland cover on the valley slopes and rolling of the seed-bed’s surface makes storm celebrating the natural wetness of riparian river water runoff even worse. Even in pastoral valley landscapes can deliver widespread landscapes, the use of artificial fertilisers, feed multifunctional benefits. supplements and veterinary pharmaceuticals has greatly increased the scope for high-density Urban areas are more challenging, livestock grazing, and this in turn has lead to particularly since land ownership is so much increased soil compaction and a serious loss of more complex. However, the concept of the natural soil absorbency. absorbent city has been made to work well on several places. Cities such as Malmo in Sweden In built-up areas the damaging elements are and Bordeaux in France have adopted an different, but the overall effect is much the incremental approach to changing landscape same. In the past, much of the rain that fell on surface treatment and delivered it gradually roofs would simply have drained into local over several years through urban economic soak-aways. Now each town and city is served regeneration process. In many other parts of the by piped storm-water drainage systems, all world each new development is required to

27 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 capture all its rainwater run-off within the buildings, and each one of them is helping to curtilage of the site. There are sophisticated slow down rainwater run-off, improve the engineering techniques that can turn water- urban scene and provide the inner city with shedding car parks into rainwater reservoirs more habitats for wildlife. through the incorporation of sub-surface storage. The range of porous paving options is The role of government agencies expanding rapidly, to include flexible materials To achieve a sustainable approach to whole such as tarmac, as well as slabs and blocks. river catchment management, there is a need Green open spaces can be designed for both for significant culture change in some key surface water management and recreation. All government agencies. At present the water of these elements are more likely to be adopted industry regulators in England and Wales, if there is a clear commitment to achieving “the OFWAT, the Drinking Water Inspectorate and absorbent city” within the context of a the Environment Agency all tend to focus the functional green infrastructure strategy. industry’s resources on hard-engineering end of pipe management. OFWAT, in particular, The thinning of the mature urban forest is continues to insist that investment in better land particularly worrying. As street and parkland management in the upstream gathering grounds trees fall victim to old age and over-zealous of water supply river systems is inappropriate health and safety paranoia, the natural use of water customers’ money. Instead they protection afforded by their canopies is being continue to sanction multi-million pound lost. New planting needs to be on a much capital investment in bigger sewers, bigger bolder scale if it is to fulfil an equally effective drinking water treatment works and bigger flood protection role. There also needs to be a sewage treatment plants. OFWAT needs to be far greater commitment to creating water persuaded that customers’ money would be well storage landscapes in the open spaces beside spent in managing the land in the gathering urban streams and rivers. There are some grounds to improve the natural quality and the inspiring examples of good practice, where more dependable year-round reliability of previously culverted water courses have been drinking water. opened up and encouraged to burst their banks in unthreatening surroundings. Similarly, whilst the Environment Agency undoubtedly has some catching up to do One characteristic of urban areas is the “land through protective construction in urban in limbo.” It is in the nature of towns and cities bottlenecks, its long term flood-risk to be in a constant state of change, with management strategy needs to be based on buildings being demolished and replaced. As a more investment in the water absorbency of part of this process, areas of land often stand whole catchments. At present the policies of temporarily idle. At present there is very rarely these two regulators seem to be determined by any positive policy for their use, although they short term, high spend accountancy and play an extremely important role as informal aggressive hard engineering. Truly sustainable recreational open space, urban wildspace, solutions are still being largely disregarded and unofficial parking etc. This land is often this despite the fact that the UK Government is porous, and even where it has an impervious bound by the Europe Water Framework surface it may have a role to play in short-term Directive, and its statutory requirement for storage of rainwater run-off. significant progress towards integrated whole One of the fastest growing positive river catchment management by 2015. interventions is at rooftop level. Covering The government’s nature and countryside impervious roof materials with vegetated green protection agencies also need to engage much and brown alternatives is now being taken more energetically. It is precisely because much more seriously. These living roofs are Natural England, the Countryside Council for being incorporated into many more prestigious Wales and Scottish Natural Heritage are

28 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 relatively short of funds that they need to make the most of every opportunity for rebuilding biodiversity and improving public access to nature, through involvement with sustainable surface water management. The active promotion of well managed, water retentive rural landscapes and reduced local flash- flooding in our towns would be an extremely effective ways of rebuilding the broad integrity of the whole landscape, improving the supply of individual wildlife habitats and strengthening nature’s capacity for coping with the impact of climate change. Conclusion Climate change is being used as a scapegoat in the debate about surface water management. Through adoption of whole river catchment management, a commitment to increasing the water retentiveness of the rural countryside, to promoting the porosity of towns and cities and to accepting planned coastal retreat it should be possible to moderate the impact of increasingly extreme weather patterns. A more sustainable and integrated approach to land and water management is now imperative. If undertaken wisely then it can deliver a whole range of social and economic benefits that will complement the environmental gains. However there will have to be a fundamental move away from short term silo-thinking, towards cross- sectoral and interdepartmental collaboration.

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Urban deforestation; it's here and it's going to hurt! Jeremy Barrell Barrell Tree Consultancy

Introduction resource. However, as the global warming Barrell Tree Consultancy provides specialist induced extremes of droughts and floods advice on trees in the UK planning system. We become more frequent, the folly of this deal with over 500 new sites every year across conventional wisdom is becoming obvious. England, which provides us with an experience- Understanding the value of rainwater as a based perception of what is happening to our resource and the harm that rapid flow from urban tree stock and how that is affecting urban areas causes is focusing attention on landscape character. This paper summarises our storing and using it where it falls to buffer its subjective assessment of the state of the urban dispersal. Similarly, through the urban heat canopy, speculates on the reasons for its island effect, there are predictions that global condition and sets out our suggestions for its warming induced temperature rises of 3–7° C future management. It is not a scientific paper are likely in many of our major cities during in the sense that it is research based; it is the next 30–50 years (Gill et al., 2007). This is experience based, but we are confident that a dramatic increase that will have multiple research will confirm our observations. impacts on all aspects of urban life, from increased bills for air conditioning to the Arboriculture is about managing trees near decreased wellbeing and comfort of city people; the common focus for arboriculturists is inhabitants (Shaw et al., 2007). on minimising the conflicts arising through proximity whilst maximising the multiple In addition to the rather intuitive benefit that benefits that trees have to offer. Typical grass, parks and trees improve the ‘feel’ of conflicts include trees casting excessive shade, urban areas, there is increasing tangible leaves blocking gutters and the mess from evidence that green space intercepts rainwater insects and falling debris causing and slows its flow into our traditional drainage inconvenience to people who live nearby. Out systems. More specifically trees, through their of sight below ground, roots are well known for size and leaf surface area, are particularly causing structural damage, whilst above the effective at slowing the rate that water reaches ground, falling trunks and branches damage and the ground and how much of it flows away. injure in a more spectacular fashion. In their Furthermore, their capability to shade and favour, trees provide a dramatic contrast to the reflect heat, combined with their verticality and harshness of the urban landscape and offer large surface area in contact with the air, makes significant benefits to the wellbeing of city them very efficient at reducing temperatures in inhabitants. Very few would argue that trees are the extremes of summer (GLA, 2006). Indeed, not good, indeed it seems to be an intuitive there is emerging research to suggest that they truth that they are, but the reality is that the are so effective at temperature buffering that an closer trees and people cohabit, the more increase of just 10% in our present urban tree fraught the relationship becomes. canopy cover would offset all but the most extreme temperature rises predicted through Set in the context of global warming, two of global warming (Gill et al., 2007). Although the most important emerging issues in urban not the answer to all urban sustainability sustainability are rainwater management and problems in isolation, big trees are obviously temperature regulation. Traditionally, rainwater part of the solution and there is an emerging has been treated as more of a problem than an body of opinion that we need more of them asset, with the focus on draining it out of cities (Shaw et al., 2007). quickly rather than storing it locally as a

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The Uncomfortable Truth as groups, they can dominate even the grandest In the hotter parts of the world, people have landscape features. Thanks to the Victorians, a long been aware of the obvious benefits of common theme of our urban landscape is large trees, with strong traditions of incorporating houses set in substantial gardens with sufficient green space into their urban infrastructure. space to live and have big trees at the same However, in the UK, mitigating the effects of time. Although they may not have had a precise hot summers has not been a familiar experience understanding of tree benefits, they intuitively and other seemingly more pressing appreciated trees were important and made sure requirements such as increased housing they featured strongly in their planning. This densities and minimising costs has resulted in principle was formally recognised during the trees being given a low priority when allocating subsequent evolution of planning policy and is funds. UK residents have not had much still with us today in the current Town & experience at coping with the heat of hot Country Planning Act (HMSO, 1991), and its summers, which has resulted in a public not supporting government guidance. However, particularly tuned into what a significant impact whilst the principle and framework for its trees can have on temperature. Against that implementation is intact, our experience is that background, although there is resistance to the the collective will to actually use it to increase idea of tree loss, the reality is that it happens the level of tree canopy cover is not in such slowly with short-lived public outcry and is good shape. soon forgotten. This low level of awareness of As arboricultural consultants, we spend the importance of trees is fostering the gradual much of our time advising on planning matters erosion of our urban canopy without a full around the country where trees are an issue. In public appreciation of the scale of the loss our travels, we have noticed a significant when considered in total. Urban deforestation is erosion of our urban tree canopy over the last occurring before our very eyes, but the process thirty years that we estimate to be a 10–20% is so slow that no one has noticed. reduction. Although there are islands of excellence where canopy cover is increasing, the nationwide trend seems to be in the opposite direction. Almost without exception, every village, town and city is losing large significant trees with either no replacements, replacements that die or new trees without the landscape potential of those they replace. The result is a dramatic change in landscape character over time; from a heritage of oak, beech and pine, there has been a gradual shift to a future of cherry, thorn and rowan. Very pretty for a few weeks of the year and very few problems compared to their bigger cousins, but with absolutely no capacity to sustain the landscapes we had the privilege to grow up Australians highly value trees because of their with. obvious temperature buffering benefits. In contrast, the UK mindset of wanting more sun rather than less It is almost as if forty years ago there was a has resulted in a gradual erosion of canopy cover. collective psychological decision to abandon the idea that trees are good and adopt the mindset that trees cause problems. In the One of the most obvious contributions of trees absence of a strongly established national to the landscape is visual; individually, they psyche favouring trees, it is easier to remove impose because of their height and width, but them rather than embrace the complications of

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sooner than that, time is running out to get this process started. More specifically, our experience suggests that overall urban canopy cover is reducing for the following reasons: Planning • Tree valuation is complicated so it is difficult to reliably factor their true value into cost- benefit analyses in decision-making. Trees are being unreasonably lost because they are not being given realistic weight compared to Landscape character is changing: the traditional large mature trees (left) are being replaced by other planning considerations. smaller varieties with no potential to contribute to • Existing trees are not being properly the wider setting in the same way (right). protected on development sites. Trees identified for retention are prematurely lost trying to understand the problem. Whilst this is because of ineffective protection. surprising in the context that we have national planning policies advocating tree planting and • New tree planting to comply with planning loss mitigation, what is alarming is that those conditions is not effectively enforced so policies are not working very well. Trees are there is a very low survival rate. Planned being shuffled to the bottom of the heap of urban canopy mitigation is not being priorities and no one seems to care. In the successfully established. context that most trees take thirty–forty years to • Inappropriate tree species are being used so mature to a size where they are most effective the new trees that do survive do not have the at delivering their benefits, failure to address potential to make a meaningful landscape the problem will take that length of time to put contribution. It is common for the smaller right. New trees planted today will take species such as cherries, thorns and rowans thirty–forty years to deliver the temperature to be planted where much bigger species would be feasible. • Weak and inconsistent interpretation of the legislative provisions by planners to maximise the potential for new tree planting. Many new developments with space for new trees, have none. • Ineffective use of existing mechanisms by planners to allow off-site mitigation planting where trees are lost and there is no space for replacements. Off-site contributions for social housing and public open space are Failed tree planting strategies are not new. This concepts that could be easily applied to tree 1970s development had real potential for big trees with space to mature, similar to those that can be planting but do not feature in mainstream seen on the skyline. Instead, it delivered a planning. landscape of cherries and rowans, with no • The potential for the dual use of space for potential to contribute to the wider setting. parking and trees is not fully exploited. Parking areas are ideally suited to large trees buffering benefits that will be needed to negate and yet this is the exception rather than the the anticipated temperature rises from global rule in many small-scale developments. warming. With the heat being expected much

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• The potential for using trees with form suited trees. Where mature trees are replaced, there to challenging site conditions is not fully is evidence that they are being replaced with exploited. Tall, thin trees, with the ability to smaller varieties (GLA, 2007). provide vertical green space with a small • There also seems to be a presumption not to footprint, are widely available but not allow new tree planting in adopted highways commonly used. despite the availability of tree pit designs to • Emerging technology for establishing and minimise the risk of problems. This means sustaining trees in difficult conditions is not many potential sites in parking areas and being effectively utilised. Products for other surfaces are not planted, which is a lost improving the below ground conditions opportunity to increase canopy cover. significantly widen the scope for successful tree establishment in previously unsuitable Land in council, private and institutional locations, but are not commonly used. ownership • Poor documentation and availability of best • Areas of open land that could accommodate performing species in urban conditions. trees without any obvious conflicts but are There is no co-ordinated record of emerging not planted. Many areas of land with little best-practice experience of the best species potential for development have a great for urban conditions and so unsuitable potential to support trees but are not used species are still widely planted, resulting in because there is no initiative to do so. high failure rates. • Poorly conceived and implemented tree planting on council owned land, which Highways and street trees cannot achieve its full potential. Councils • Highway engineers often perceive trees as should be setting the example and yet it is being a problem they would rather not have common to see inappropriate trees planted and there is no active policy to replace those ineffectively on their land. removed. Indeed, our experience is that there • In some civil subsidence claims, the is a presumption not to replace removed judiciary have implicated trees in damage with very low levels of evidential support. This results in councils being reluctant to resist demands to fell from allegations of subsidence damage; trees are removed, despite very little evidence that they caused damage, because it is too risky to go to court.

A recent council development with great potential There is robust resistance from highway for large tree species. Instead we have cherries, authorities to planting trees in and near the thorns and rowans, with no potential to contribute highway despite tried and tested methods of to landscape in the same way as the trees over the doing so. road.

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• Insurers are not factoring tree values into reasons in itself is actually quite minor. We subsidence cases, which often results in high believe this is cause for optimism because it value trees being removed to deal with low indicates that a workable solution could consist value claims. of lots of minor changes and adjustments, There are obviously many reasons why trees rather than one big fix. Big changes are tough are being lost and not effectively replaced. to do because they cost money, existing Slowly but surely all those losses are adding legislative frameworks need updating and up, but it is only when they are considered people have to alter their lives. In contrast, together that the cumulative impact can be fully small changes are not so hard; an adjustment appreciated. Furthermore, this is not a localised here, increased emphasis there, better trend; almost invariably, we see it in every understanding of the reason to change and a co- town and city we go to. It is significant and has ordinated approach are not going to have a resulted in a countrywide decrease in urban tree dramatic impact on everyday lives. However, canopy creeping up on us without anyone really together their cumulative impact could be very noticing. We are witnessing a widespread effective indeed. Localised big changes are not change in the quality and character of our urban necessary; widespread and co-ordinated small landscapes. Less obvious but equally important, changes are a low impact strategy with the potential for a high impact result. In principle, small changes in our approach to trees have the potential to increase urban canopy cover, with very little impact on our daily lives. But, who has to do what and what is required to make it all come together; it has not happened in the past so what will make it happen in the future? Of course, the driving force has to come from government by formally identifying the need and directing that Today’s developments without trees are likely to appropriate emphasis is given to it. Politicians become tomorrow’s slums. should not find it difficult to align to such an obvious good cause; there is increasing this decrease in canopy cover is damaging our scientific support that it is necessary and the capacity to mitigate the anticipated temperature idea of temperature buffering connects straight rises we will all have to face in the next few to the public. On the ground, nurserymen, tree decades. managers and product designers have the expertise to develop solutions, but the incentive to do so in a co-ordinated way is missing at the Can This Trend Be Reversed? moment. With government acknowledgement In the absence of detailed knowledge on the providing the strategic impetus and the implications of tree loss, it is understandably practitioners developing solutions, the middle easier to lose a tree to save time and trouble managers will have little option but to give now, even though deep down we all know that trees more weight in the decision making there is likely to be some dark consequence in process. A joined up approach to urban the future. There must be some truth in this management, with trees as an essential element because the landscape degeneration is so of sustainable development, will outlaw the widespread. But, how hard would it be to ‘fell it now and worry about it later’ attitude reverse that trend and would it be so difficult that has resulted in the current urban that it is not realistically feasible? Our deforestation crisis. experience shows that there are many reasons Here are some small changes that will result in for decreasing tree canopy and each of those increased urban canopy cover:

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• Politicians: Central government to • Nurserymen: Seek feedback from maturing acknowledge the temperature and rainwater planting projects to identify the species and runoff buffering benefits of trees and their forms most successful in tough urban contribution to sustainable development. conditions. Trial non-traditional species that Modify existing government guidance to have a track record of tolerating greater ensure that increasing canopy cover is given temperatures and coping with the harshness significant weight in the planning process. of the urban environment. Identify, promote Regional and local government to and supply species and forms that are likely incorporate urban canopy cover targets into to be most suited to sustainable urban their structure plans. development. • Planners: Factor urban canopy into planning • Highway engineers: Review traditional decisions and consider off-site planting approaches to trees in highways; assess the mechanisms where new tree planting is not feasibility of replacing all lost trees and sustainable on-site. Improve enforcement of encouraging the establishment of new trees planning conditions relating to new tree where there is a low risk of problems. planting and protection of existing trees. Encourage a positive attitude towards the • Architects: Give canopy cover significant evolution and use of adoptable planting pit weight in new designs where trees will designs. enhance the architecture and improve the • Hydrologists: Incorporate the emerging quality of living conditions through their technology of soil cells for the dual use of temperature buffering benefits. growing trees and buffering rainwater • Urban designers: Incorporate designer trees runoff. into urban areas where special forms and • Insurers: Agree minimum levels of site growth characteristics make them more investigation with other professions for sustainable than traditional species. Place implicating trees in subsidence damage. greater emphasis on the dual use of space in Factor realistic tree values into claim parking areas by incorporating trees through settlement. the increased use of special below-ground • Judiciary: When implicating trees in preparation. subsidence damage, be mindful of the value • Tree officers: Provide specialist backup to of trees and, if appropriate, place significant local politicians, planners and urban weight on the evidential requirements set by designers on tree species and forms that the appropriate professions and the local reduce inconvenience to future occupants incidence of damage. For every case of and maximise the efficient use of available damage, there are many more similar space. Identify unused urban planting sites to relationships where damage has not tie in with off-site planting arrangements occurred; being big and close to damage, relating to high-density developments that does not automatically implicate. cannot accommodate new trees. • Public: Lobby local councils about canopy • Landscape architects: Identify and publish cover strategies, register their views where guidance on the importance of tree size tree issues are a part of planning applications potential as a strategic objective of new and plant their own trees where appropriate. planting schemes. Review traditional Register disapproval when insurance planting strategies and compile revised companies remove high value trees to solve species lists based on maximising size small value problems and the judiciary potential for the space available whilst sanction tree loss on weak evidence. minimising the inconvenience for future users.

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Great foresight in Poundbury, Dorset. Apart from its obvious aesthetic benefit, this plane will mature Sustainability in practice: the silvacell installed with a crown well above the rooftops, offering below ground in Redwood City, California. valuable shade in the summer without restricting Rainwater from the roof and hard surfacing is too much light in the winter. collected in soil-filled cells beneath the drive and street, buffering the immediate flow into the main DeepRoot Case Study drainage system and watering the street tree planted into the soil. Our experience is that most, if not all, of the solutions are out there as ideas and products, problem that has prevented many urban sites but have not yet been promoted, explained and being planted, and just one illustration of made accessible for those who need the creative ideas delivering multiple benefits. information. One such product is the silvacell from DeepRoot, a company based in the US Where Do We Go From Here? where the role of trees in temperature and It has been known for some time that trees will rainwater runoff buffering is being extensively play an important role in mitigating the adverse researched. The silvacell is an emerging impacts of climate change in our cities, and that experimental product with very good potential there is increasing evidence of a trend of urban for improving the success and viability of new deforestation. It is also widely accepted that trees in the toughest urban environments. It is a more trees need to be planted, with some steel-reinforced plastic frame that is installed significant emerging initiatives working beneath hard surfacing and capable of piecemeal towards that goal. Perhaps supporting normal vehicle loading. Its high understandably, there is a strong focus on proportion of voids are filled with soil, which numbers, which seems an intuitive and allows roots to grow and trees to flourish where reasonable test of performance. However, they would have failed using traditional successfully increasing urban canopy cover is planting techniques. The cells can be stacked in more likely to be influenced by the calibre of almost any configuration and provide a the tree survivors than too much reliance on the continuous rooting environment that can be measure of numbers planted. Understanding the tailored to the specific requirements of each issues in depth and co-ordinating meaningful site. What is particularly relevant about this initiatives will be an important element of a product is that, in addition to providing a successful approach to the problem. Getting all rooting medium, it is also designed to take the interested parties working together, with a rainwater runoff to buffer the gluts after storms. focus on what to do, where to do it and who This slowed water release mimics the flow does what, seems to be lacking at the moment. from natural areas without surfacing. More information on the product with very useful In response to that need, a group of picture series of its installation in the US and arboriculturists have established the UK Urban Canada can be found at www.deeproot.com. Canopy Initiative, dedicated to reversing the This is a technical solution to a practical trend of urban deforestation and increasing canopy cover. In a two phased approach, the

36 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 first task is to explore all the barriers to Shaw, R., Colley, M., and Connelly, R. (2007) increasing tree cover and identify the detail of Climate change adaptation by design: a guide the solutions, so that everyone who wants to for sustainable communities. TCPA, London. help knows how to do their little bit to gain a Town and Country Planning Act. 1990. HMSO, big benefit. The second phase will focus around London, UK. 358 pp. collating all those solutions so they are easily accessible in one place, probably a central Jeremy Barrell website. With the means of delivering increased Barrell Tree Consultancy canopy cover spelled out, an effective strategy Field House for implementation will rely on a simultaneous Fordingbridge Business Park drive from politicians making it a strategic Ashford Road objective and a surge from enthusiasts on the Fordingbridge ground insisting it can be done. Hampshire SP6 1BY

0044 1425 651470 The first phase begins on 10 July 2008 with [email protected] a landmark seminar organised by the Treework Environmental Practice (TEP) called Trees: the key to climate proofing our cities (Part 1) (Strategic urban planning to mitigate climate change risk) to be held at the Royal Geographic Society HQ in London. An impressive international line-up, led by the UKs Professor Chris Baines, will explore how trees can help and what needs to be done to unlock their benefits, as the first step towards achieving the objective of increased urban canopy cover. If you are interested in finding out how you can help, then visit the TEP website at www.treeworks.co.uk. Although arboriculturists are driving this initiative, it will only be successful with multidisciplinary support and everyone doing their little bit towards a very big end. References Gill, S., Handley, J., Ennos, R., and Pauleit, S. (2007) Adapting Cities for Climate Change: the Role of the Green Infrastructure. Built environment, 33(1): 115–133.

Greater London Authority (2006) London’s Urban Heat Island: A Summary for Decision Makers. GLA, London.

Greater London Authority (2007) Chainsaw massacre – a review of London’s street trees. GLA, London.

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North Cave Beck Catchment Area Project Bill Blackledge

Like many villages and towns across East Consultancy, who are involved in both North Yorkshire, North Cave was flooded on 25th Cave village life and wider environmental June 2007. There is no Cave in the area - the initiatives, have proposed a review of place name is derived from the Anglo-Saxon sustainable drainage practice for the Beck’s “CAF” meaning fast-flowing stream! The catchment area. stream, North Cave Beck at this point, is fed North Cave’s Flood Committee has from a substantial catchment area of approved the principle. A request for support approximately 38 sq km, in the Yorkshire has been made to Hull and East Yorkshire Wolds to the east of the village. Due to the Woodlands Initiative (HEYwoods large catchment area and the exceptional www.heywoods.org.uk) of which 2B are rainfall, the Beck was perhaps 10-20 times its steering group members. In December 2007, a normal volume, and it was this, as well as proposition was presented that the HEYwoods locally falling rain, which caused the flooding. partners (including Forestry Commission, In this respect, it was probably a smaller Environment Agency, Natural England etc) version of what happened in Sheffield and the consider a North Cave Beck Catchment Area eastern moors of the Peak District. project. The response to these events has largely The project’s main aims would be to been based around the traditional measures of determine whether habitat and farming changes clearing out local ditches and streams to in the catchment area might make a difference improve flows. As yet, limited thought has been in future extreme weather events, and then to given to sustainable drainage principles of seek cooperation with local landowners and water retention and peak flow reduction. Local farmers in implementing possible changes. landscape architects, 2B Landscape

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HEYwoods proposed a motion to support the other landscape measures, such that we might project, with a view to it possibly having be able to determine what amount of habitat repeatable benefits in other areas of East change would be required to have a beneficial Yorkshire. effect. If we can assess the benefits of specific measures, we would then be able to determine 2B are also working as consultants to a the scope of required changes and the gravel extraction site to the west of North Cave, feasibility of entering into discussion with which has been designed with an after use as an landowners. HEYwoods’ past successes in extension to the current North Cave Wetlands negotiation and partnership with landowners (YWT) Nature Reserve. There is a proposal would be invaluable at this stage. under consideration that this low-lying area might act as a potential sump for flood water, in the event of future extreme weather events. The Catchment Area project’s particular interest in the Floods Water and Landscape Conference is to identify any research pointing to measurable benefits from riparian tree planting, floodable meadows and wetlands, and

39 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008

Farming And Flood Storage Graham Coultish

The present policy to prevent flooding on perpetuity for the land-owner. The storage certain rivers is to use areas of agricultural land schemes are built usually for protection of for the storage of flood water out of the urban development. Should some form of adjoining river to stop flooding in urban areas taxation be levied on the developers to pay lower down the river. I believe that this policy for the storage of water in these schemes? is in conflict to produce both food and energy • When planning these storage areas try to tap off a reducing resource. Most land adjoining into local knowledge instead of relying on rivers is classified in the top two grades of soil computer models. fertility which historically has occurred due to • The single farm payment scheme which flooding and the natural movement of the rivers Defra uses to reward farmers for managing over thousands of years. Hence there are some land should also be taken into consideration areas of very productive land both arable and when planning these schemes as loss of land grassland adjoining our river systems. In future, due to flooding can have a large impact to with climate change it is vital that we are able the amount payment received. to maximise our production of food and also of renewable energy off these areas of land in • These flood schemes are also seen by the flood plains. The main arable corn crops, such naturalists as prime sites for wading birds as wheat and barley, are autumn sown together and an opportunity to draw down some with oilseed rape which is not flooding tolerant environmental money from Defra in the over a length of time. On the other hand, areas form of Higher Level Schemes. These of grassland are more flooding tolerable and schemes are too prescriptive and the will mainly regrow after a period of flooding. payments do not compensate for the change Unfortunately these areas of grassland tend to of land use. be further up toward the heads of many rivers with the arable crops lower down. The above points are relevant at the planning stage of any scheme proposal. If the future of flood control is going to be creating temporary storage areas on farmed If the scheme goes ahead and is built how do land the following points should be considered: you continue to farm the land within the scheme productively within the constraints this • Are there areas of land that are non-farmed imposes? or of poor quality? • Areas of permanent grass may be more The following is my experience of doing suitable as long as they are remodelled as to such: allow quick evacuation of the flood water The area is divided into two adjoining areas of back into the water coarse. flood storage. Both areas were farmed both • Processes need to be in place to facilitate growing arable crops. One area was quarried removal annually of debris that usually is for sand and gravel about forty years ago and left after flooding. This cost of removal then restored. The restored areas were put down should be borne by the authorities not the to grass for agricultural use. An area of water land-owner. was left and is used for fishing and an area of • If areas of productive land are to be flooded, woodlands, mainly silver birch and willow, a proper scheme of compensation should be planted. The second area was quarried and developed not just a one-off payment in restored in the last ten years and consists of

40 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 three lakes and there are two areas of reed beds. species that are tolerant to wet conditions is The rest of the site, which includes areas of important, as if the scheme is used the grass mowable grass, is for agricultural use. needs to be capable of recovery after the flooding. The management of the two sites has to be sustainable and produce an income. The Last summer’s flooding showed that large constraints of the sites are that, being near to amounts of agricultural land held a lot of flood large areas of water the use of any fertiliser or water which it should have due to lack of herbicides have to be strictly regulated in their maintenance of IDB dykes and infrastructure. use and amount applied. There are areas of the This is due to government lead policies and site that are restricted to their uses due to the shortage of finance. operational nature of the site as a flood storage area, e.g. spillways. There are the ground- If a sustainable method of flood water nesting birds and the birds on the lakes to management is to include flooding agricultural consider, so operations have to be planned land the development of flood plains should around nesting seasons. include urban drainage schemes that are capable of holding water off these development The smaller of the two sites has been farmed areas till the rivers and watercourses can take for a longer period since quarrying ceased so them. has a more established infrastructure. The effect of it becoming a flood storage is that certain areas of the land have standing water creating flashes. The building of the bund had caused this due to the drainage of the land being outside the site. The bund has thus cut off the drainage and due to the topography of the site has nowhere to drain to. With the drainage of the site compromised the areas of the site that are farmed will vary from year to year depending on the amount of good weather that occurs in the summer months. As this site is not graded to the river and the outfalls structure, if the water storage compartment is used a large area of this land will become permanently flooded. The other sources of income from this site are from the lake, which is rented to a local fishing club. The second larger area has over the past ten years been restored to grassland around the lake margins using a grass mixture that stabilises the lakeside margins. As the soil fertility was very high various mixtures have been used to reduce this fertility. This has been achieved by taking numerous cuts of grass annually off the site. It is only after about ten years that the fertility is declining The grass has to be cut and removed as if it is cut and left it only helps to build soil fertility. The lower fertility of the soil creates more problems of invasive weeds such as thistle, ragwort and docks. The use of grass

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An Urban Catchment Scale Approach For Exploring The Use Of Brownfield Redevelopment For Pluvial Flood Risk Management J. Diaz Nieto1*, J. Blanksby2, D.N. Lerner1 and A.J. Saul2 1 Catchment Science Centre, Kroto Research Institute, The University of Sheffield, North Campus, Broad Lane, Sheffield, S3 7HQ

2 Pennine Water Group, Department of Civil and Structural Engineering, The University of Sheffield, Sir Frederick Mappin Building, Mappin Street, Sheffield, S1 3JD * Corresponding author: [email protected]

Introduction Method Recycling brownfield land is currently To explore the use of brownfield redevelopment perceived as a sustainable option for urban for flood risk management, sites of all sizes development because it reduces development need to be considered in terms of their on greenfield sites. With the exception of hydrological connectivity within the urban landmark buildings most urban land will catchment. In an attempt to simplify existing eventually be recycled in this way. Government approaches, the methodology is based on the policies and targets (ODPM, 2000) for new computation of the water balance for the urban development to be located on previously surface. Surface sinks can act as storage areas developed land are leading to increased rates of but are also potentially areas of localized recycling of brownfield land. At the same time flooding. Sinks, and their corresponding there are serious concerns regarding urban contributing catchments also form complex flooding and the potential impacts of climate nested patterns across the urban catchment, change, and many of the responses suggested with very small sinks nested within several for dealing with urban flooding relate to levels of larger sinks and their corresponding development design (Evans et al., 2004), catchments. This conceptually simple water despite the fact that major changes in urban balance approach is executed in a GIS and is form are not feasible due to the enormous based upon very high resolution delineation of disruption and cost that would be involved. sinks and their catchments (using Lidar derived This means that the only windows of digital elevation models) and identification of opportunities for building in capacity to deal the nesting patterns. Using the computed with urban flood risk are those pockets of land catchment areas and sink volume, surface water that become available for redevelopment. This is accumulated up through the various nested raises the question of whether the rush to catchments at the urban catchment scale. redevelop urban brownfield land, without Additional functionality will be incorporated proper consideration to the scope it may offer into the model to generate surface water in urban flood risk management, is rapidly volumes that take account of runoff coefficients reducing our capacity to manage urban flooding and urban drainage capacity. problems, especially given the uncertainty This simple approach will identify areas that surrounding climate change. This research will be prone to localized flooding (sinks that addresses the following issues: receive huge amounts of surface water) and • Can brownfield redevelopment be exploited also highlight areas of major flow accumulation to manage urban pluvial flood risk? across the catchment. The proposed • How can brownfield redevelopment best be used to manage urban flood risk?

42 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 methodology contrasts existing approaches References where surface flows are calculated between ODPM (2000) Planning Policy Guidance 3: designated sinks and connecting channels. Housing, Norwich, The Stationery Office. Results Evans, E., Ashley, R.M., Hall, J., Penning- This research uses the town of Keighley in Rowsell, E., Sayers, P.,Thorne, C. & West Yorkshire to apply the methodology. Watkinson, A. (2004) Foresight. Future Keighley suffered from quite severe flooding as Flooding. Scientific Summary: Volume 2 - a result of pluvial rainfall patterns and therefore Managing future risks. London, Office of provides a perfect case study for exploring the Science and Technology. surface water balance. Figure 1 shows an example from a small section of the urban catchment which illustrates how the build up of surface water occurs across the nested surface sinks. The results from the water balance methodology (as shown in Figure 1) will be compared and contrasted with the conventional approaches adopted in standard industry software. Initial comparisons show relatively good agreement. Future application The developed methodology will be used to answer the question of whether as brownfield land becomes available, albeit sporadically (in time) and in disconnected patches, is there an opportunity to adopt a long term strategy for sustainable management of urban flood risk? By overlaying all the sites up for redevelopment with the urban surface water balance, potential opportunities can be identified for building in capacity to deal with pluvial flood risk. A range of redevelopment scenarios are then represented in the urban topography and fed into the model to explore the changes generated in water balance. A simple pluvial food risk measure will be used to compare and evaluate the impacts of the various scenarios.

Figure 1: Water balance results for 1mm of rainfall on a 100% impervious catchment.

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Green Roofs And Urban Hydrology Nigel Dunnett Director, The Green Roof Centre Reader in Urban Horticulture Department of Landscape, University of Sheffield

Introduction and have produced incentives and programmes Green roofs are engineered systems that to support that development, with the result that support vegetation growth on rooftops to make green roofs are a common and accepted feature environmental, economic and social in those cities. Green roofs are best known contributions to urban areas, providing both when used on the large scale: on schools, public and private benefits. These systems offer offices, factories and other big buildings. The multiple benefits to urban areas. The key point opportunities at a small scale are equally great is that they are living systems and can but have tended to be overshadowed by their contribute to actions aimed at combating a larger counterparts. range of urban environmental problems that are a direct result of a severe lack of vegetation, What are Green Roofs? soils and greenspace within high density urban A typical green roof consists of a number of areas. When applied to a specific building they layers above the waterproof and insulation can reduce the building’s cooling and heating layers of a roof. It must be stressed that a energy demand, thereby reducing CO2 properly constructed green roof is not a threat emissions; reduce site-level stormwater runoff to the waterproof integrity of a roof surface, and associated pollutant loading of Indeed, so long as the roof is properly sealed, watercourses; and extend the life of the roof. then a green roof layer can provide valuable When widely adopted they can mitigate urban protection from temperature fluctuations and heat island effects; improve urban air and water ultra-violet radiation, and thereby actually quality for the local community; reduce impact protect and extend the life span of a roof on the regional watershed and reduce urban membrane. flooding problems; increase biodiversity and Typically, the first layer above the wildlife habitat; and through contributing to a waterproof membrane is the drainage layer. greener urban environment, contribute to Green roofs turn our normal interpretation of improved quality of life for urban citizens in rainfall runoff on its head. The water that high density developments. Initially confined to escapes a green roof is actually ‘underflow,’ or Western Europe (particularly Germany and percolated water. Surface runoff should not Austria) for the past twenty five years, the occur at all on a well-designed green roof adoption of green roof technologies is presently (Miller, 2003). The function of the drainage increasing worldwide. In particular, the so- layer is to remove excess water or underflow as called ‘extensive’ green roof technology (very rapidly as possible to prevent over-long lightweight, low maintenance, vegetated roof saturation. Note the term excess – drainage is surfaces, as opposed to traditional maintenance- only necessary if the growing medium is intensive roof gardens) has been adopted already saturated. The drainage layer in some widely because of its capacity to be ‘retro- instances may also double up as a means of fitted’ onto existing buildings, or incorporated introducing irrigation. Drainage of excess water onto new buildings without the need for major is necessary for several reasons: green roof structural modification or support. Several vegetation, particularly of the extensive type, is European cities have developed specific green selected to be drought-resistant and tolerant of roof policies that require the implementation of dry, free draining soils, prolonged saturation of green roof infrastructure in new development,

44 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 the soil is likely to cause plant failure, rotting into new build, or retro-fitted on to existing and ‘sour’, anaerobic conditions. Collection of buildings if suitable. Green roofs can be used to water may increase the weight of the roof attenuate and reduce stormwater runoff at beyond its carrying capacity. Drainage layers in source. They influence roof water run-off in a commercial green roof systems tend to plastic number of ways. Water that falls on the roof ‘egg cup’ type layers, but can also take the can be absorbed into pore spaces in the form of porous mats, or layers of lightweight substrate, or taken up by absorbent materials in granular material. the substrate. It can also be taken up by the plants and either stored in plant tissues or Where a drainage layer is included a filter transpired back to the atmosphere. Some water mat (semi-permeable polypropylene fabric) is may lodge on plant surfaces, and subsequently laid loosely over the drainage layer and evaporate away. Water may also be stored and prevents fine material from the growing retained by the drainage system of the roof. By medium being washed into the drainage layer absorbing water and returning it to the thereby blocking pore space. These particles atmosphere the roof reduces the amount of may also cause blockage to drainage outlets. water available for runoff, and by storing it for Plants grow in a growing medium or a period before it runs off, it acts as a buffer substrate. The ideal substrate has to achieve the between the weather and drainage systems. seemingly miraculous combination of being Water stored by the green roof is gradually highly efficient at absorbing and retaining water released over a period of time, so that the peaks whilst at the same time having free draining of heavy rainfall characteristic of storms, properties. It should also be able to absorb and especially summer storms, are evened out, with supply nutrients and retain its volume over the result that drainage systems are more able time, as well as providing anchorage for the to cope with the amount of water entering the plants of the green roof. This is generally system. In cases where there is a heavy achieved by granular mineral materials that downpour there may be too much water for the absorb water and create pore space, mixed with drainage network to cope with. This can result fine particles (in relatively small proportion) to in flooding and the possibility of sewage being which water will cling (Miller, 2003). forced through the system before there has been Typically, extensive green roofs contain around adequate time to treat it. 10% organic matter content. Investigating the reduction and management Green roof vegetation can take many forms. of stormwater runoff has been the most active Stonecrops or sedums are the most common research area in the roof-greening world, with type of plant to be used. Sedums grow naturally in dry habitats, rocky or sandy habitats, and several species colonise old roof surfaces spontaneously. There is currently great interest in the use of green roofs to support wildlife habitat.

Green Roofs and Urban Drainage Because roofs represent approximately 40-50% of the impermeable surfaces in urban areas, green roofs have a potentially major role to play in reducing the amount of rainwater rushing off these surfaces. The roof surface is Figure 1: Section through a typical green roof. unique amongst urban surfaces in that there is usually little or no competition for uses other than greening. Green roofs can be incorporated

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are constructed, often incorporating both level and inclined areas. Such experimental facilities may be sited on top of existing or purpose-built buildings, but often take the form of flat tables or containers at ground level with no direct connection to an actual building. Comparisons with conventional ungreened areas are always a vital part of these test areas. Flow meters with an electronic rain gauge are typically connected Figure 2a: A drainage layer being layed above a to each individual test bed are linked to a water-proof roof surface. central computer, so that exact measurements of runoff and precipitation can be taken and then plotted against time. The storage capacity of a green roof varies with the season of the year, the depth of substrate, the number and type of layers used in its construction, angle of slope of the roof, the physical properties of the growing media, the moisture content of the substrate, the type of plants incorporated in the roof, the intensity of Figure 2b: The same roof with vegetation. rainfall, and the local climate. It is therefore dangerous to generalise from results of any particular studies, particularly if they were conducted in a different climate regime. However, most research indicates yearly reductions in runoff of between 40-60 and up to 80 per cent. In a wide-ranging review of studies in Germany, Mentens et al. (2006) identified an average annual retention of 45% for extensive green roofs with a substrate depth of 100mm, and 75% for intensive green roofs. Substrate depth was the main determinant of how much water was retained. Moreover, Peak runoff Figure 3: The typical effect of a green roof on rainfall run off. The runoff from the flat roof rates, as measured in mm per hour of runoff mirrors closely the amount of rain falling on the can be considerably reduced. For example, the roof and its intensity (not shown) over the period of average rate of reduction on test green roofs recording. The comparison of runoff from a typical over the period April to September was 51%, conventional flat roof with an extensive green roof with a greater rate of reduction for smaller shows that not only is the total amount of run off reduced (and the peak run off reduced storms (Moran et al., 2005). considerably), but the there is a delay in water A study in Portland, Oregon, showed that draining from the roof, and the rate of run off is relatively constant after the initial surge. This over two years, an extensive green roof pattern is found consistently from experimental measuring around 10 cm (4 in) in depth roofs across the world. Redrawn and adapted from absorbed 69 per cent of all rainfall falling on it, Kohler et al. (2001). with 100 per cent retention for most warm- both state-funded research institutes and weather storms (Hutchison et al. 2003). commercial bodies actively involved. Retention differs according to the existing roof Techniques typically include the construction of moisture content—less rainfall is likely to be experimental roofs, where test beds using retained if there has been recent rainfall different combinations of materials and planting because the substrate is likely to be near its

46 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 water holding capacity (Rowe et al., 2003). roof has attained its moisture holding capacity, There is a considerable difference between the then any extra water will simply run off. There amount of water retained in summer and in is a considerable difference between the amount winter, due to the much greater amount of of water retained in summer and in winter, due water that can be returned to the atmosphere in to the much greater amount of water that can be summer through evaporation and transpiration: returned to the atmosphere in summer through retention rates in summer can be between 70 evaporation and transpiration: retention rates in and 100 per cent but in winter only 40 to 50 per summer can be between 70-100% but in winter cent (Peck et al., 1999). German research only 40-50% (Peck et al., 1999). agrees, with extensive roofs with 10 cm (4 in) of substrate absorbing 90 per cent of The presence of vegetation and substrate precipitation in summer and 75 per cent in invariably significantly reduces runoff from flat winter (Köhler et al., 2001). However, it is roofs. For example, Rowe et al., (2003) summer rain that is more likely to involve the recorded runoff from experimental roofs in heavy downpours that overload drainage Michigan over a six-week period in late systems. The work of Optigrün (2002) in summer and autumn. The roofs were covered Germany indicates that roof gradients of up to by either a 12-cm (4.8-in) layer of gravel or a 15 degrees make little difference to runoff layer of green-roof plant growing substrate, quantity. The company’s work also suggests with or without a vegetation covering of that the effect on runoff begins to tail off with sedums. The study revealed consistent substrates deeper than 15 cm (6 in), with little reductions in runoff with the presence of advantage to constructing deeper layers. Further growing media compared to the simple gravel- evidence for this variation in performance is covered roof. The presence of vegetation shown in Figure 4 which shows how the runoff achieved additional runoff reduction following from a test green roof in Georgia varied with heavier precipitation. Similar results come from the amount of rainfall in a storm event over the a study in Belgium that indicated increasing period November 2003 to November 2004. water retention benefits with increasing substrate depth and presence of vegetation In general, the greater the rainfall, the less (Table 1). Even on the standard, ungreened roof water the green roof retains. For small storms, there is some reduction in runoff when the roof retains all or virtually all the rain that compared with the total amount of water that falls on it. This is mostly related to the moisture falls on the roof – this can be attributed to holding capacity of the substrate – once the evaporation. Addition of a gravel layer results in some further reduction, but the greatest reduction is achieved with an added vegetation layer.

Table 1: The influence of substrate and vegetation on green roof hydrological performance.From Mentens et al 2006.

Figure 4: Green Roof Stormwater Retention over the period November 2003 to November 2004 in the Georgia Piedmont. Adapted from Carter and Rasmussen (2005).

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Whilst most work has focused on the River, which has certainly given extra impetus influence of individual roofs on the quantity of to the city’s water management strategy. Both runoff, some studies have taken a wider view of state and city governments in the United States how green roofs might contribute on a wider are increasingly charging fees for connection to level to reducing urban flooding problems. For storm-water systems or allowing developers tax example, modelling by Carter & Jackson breaks if they use systems to reduce runoff. (2007) suggested that the greatest contribution Indeed in some counties in the arid western of green roofs in reducing pressures on water- states, new developments need to demonstrate sheds is in low-intensity to moderate storms, zero runoff from the areas they occupy. whereas in extreme storm events their contribution is reduced because once the roofs Water management on vegetated green roofs are saturated their effect lessens. This finding is offers great design potential. Cisterns and wells supported by Mentens et al., (2006). They also can store water for later use, and storage pools indicated that the most effective targeted and ponds can be attractive features in application of green roofs for hydrological themselves. Where rain water or recycled grey benefit is to retro-fit or incorporate into water from the building is being filtered industrial areas dominated by shed-like through planted wetland vegetation (either on warehouses. However, when combined with the roof or at ground level) there is much other elements of low-impact design green opportunity to be creative with both the roofs make a significant and cost-effective planting and the design of containers, planters, option (Montalto et al., 2007). Mentens et al., and pools. 2006 suggested that greening of 10% of the There is a great need for further research to roofs in Brussels would result in a total generate UK specific data. The UK climate is reduction in runoff for the entire region of maritime compared to the continental climates 2.7%, with greater reductions in the city centre, in which most, if not all, green research has and again make the point that green roofs are been conducted to date. The frontal rainfall only really effective as mitigation against the which is characteristic of the UK results in effects of extreme rainfall if combined with higher rainfall amounts, and reduced other sustainable drainage measures. evaporation compared with continental Governments are increasingly setting locations (Virginia Stovin personal standards for both the reduction of storm-water communication). runoff and the quality of any that does occur, Runoff Quality providing powerful reasons for green roofs to be taken seriously by policy makers at local As well as reducing run-off quantity, extensive government level. Such policies are common in green roofs may also have value in improving German cities, some major American cities, and the quality of runoff, by reducing pollutant are now being considered in some British cities. release. For example, recent German research For example, in Portland, Oregon, the city has has shown that green roofs on the buildings of drawn up building codes that give bonuses for Potsdamer Platz in Berlin (specifically designed developers who include green roofs in their for water quality improvement through the use buildings, so that for example, for every 0.09 of coarse media and drought-tolerant sedum square metres (1 square foot) of green roof varieties) have been highly effective. The created they are allowed an extra 0.27 square purpose of the roofs is to reduce nutrient metres (3 square feet) of floor space. In one loading in runoff which results in algal blooms case under this code, a developer was allowed in the River Spree which runs through Berlin to build an extra six condominiums, worth $1.5 (Charlie Miller, personal communication). This million (Liptan, 2002). In Portland the issue of is supported by Berghage (2007) who found runoff is closely associated with the pollution that the total quantity of nitrate (a prime culprit of salmon spawning grounds in the Columbia in the nutrient enrichment of water courses) in the runoff from green roofs was significantly

48 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 less than that from unvegetated roofs (as a lightweight sedum green roof systems resulted result of the reduction in the amount of runoff in high concentrations of Nitrogen and itself). He also found that the pH of green roof Phosphate in the runoff. They suggest a review runoff was consistently higher than that of of whether fertilisor application is necessary as ungreened roofs. This is a beneficial outcome part of a standard maintenance regime, and in terms of combating the effects of acid rain. propose considering a move away from an The main difference in quality between greened aesthetic dominated by lush green sedum and ungreened roofs was the colour of the growth which demands nutrient addition. runoff water: that from green roofs consistently Where fertilisor is used they urge that it is having a yellow colouration, although it was always a slow-release type. always clear. This may be disadvantageous is the water is to be harvested and re-used for toilet flushing for example, and he recommends References green roof runoff is circulated through a reedbed system or similar before re-use If Berghage, R. (2007) Green roof water runoff colour is an issue. The concentrations of other quality. In: Greening Rooftops for Sustainable chemical elements in the runoff varied as to Communities, Proceedings of the Fifth North whether it was significantly higher or lower in American Green Roofs Conference, the green roof runoff. However, Berghage Washington DC, May 2007. The Cardinal makes the important and crucial point that Group, Toronto. increased concentration of a chemical element Carter,T. & Jackson, C. (2007) Vegetated Roofs in green roof runoff should not be seen in for stormwater management at multiple spatial isolation. The actual loading of these elements scales. Landscape and Urban Planning, 80, 84- in the runoff was so low as to be of no practical 94. significance. But most importantly, the nutrient concentrations in the green roof runoff were no Carter, T. & Rasmussen, T. (2005) Use of different than those which might be expected to Green Roofs for Ultr-Urban Stream Restoration occur from any area of urban green space or in the Georgia Piedmont (USA). In: vegetated ground. Proceedings,Third Greening Rooftops for Sustainable Cities, Washington, May 2005. However, there do appear to be two factors Green Roofs for Healthy Cities, Toronto. that can significantly increase nutrient loading in green roof runoff. The composition of the Emisson, T., Berndtsson, J., Mattson, J. & Rolf, growing substrate or medium may have K. (2007) Effect of using conventional and influence. Some mineral materials may leach controlled released fertilisor on nutrient runoff elements such as Phosphorus in the early on from various vegetated roof systems. after green roof implemtation (Van Seters et al., Ecological Engineering, 29, 260-271. 2007). This ‘first flush’ is not a long-term Hunt, B., Hathaway, A., Smith, J. & Calabria, J. feature but may be significant in sensitive (2006) Choosing the right green roof media for areas. Moran et al. (2004) and Hunt et al. water quality. Greening Rooftops for (2006) observed that growing media with Sustainable Communities. Proceedings of the higher proportions of compost (30% of total Fourth North American Green Roofs volume) had significantly greater leaching of Conference, Boston, May 2006. The Cardinal phosphorus than those with lower proportions Group, Toronto. (10% and 5%), and recommended that green roof growing media should not be compost-rich Köhler, M., Schmidt, M., Grimme, F. W., Laar, if water quality is important. The second M., and Gusmao, F. (2001) Urban water important factor relates to fertilisor application. retention by greened roofs in temperate and Emilsson et al. (2007) found that application of tropical climates. Proceedings of the 38th conventional (rapid release) fertlisers to thin

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World Congress of the International Federation of Landscape Architects, Singapore. IFLA, Versailles. Liptan, T. and Murase, R. (2002) Water gardens as stormwater infrastructure (Portland, Oregon). In: France, R., (Ed.) Handbook of Water- Sensitive Planning and Design. Lewis Publishers, Boca Raton, Florida. Mentens, J., Raes, D. and Hermy, M. (2006) Green roofs as a tool for solving the rainwater runoff problem in the urbanised 21st Century. Landscape and Urban Planning, 77, 216-226. Miller, C. (2003) Moisture management in green roofs. Greening Rooftops for Sustainable Communities, Proceedings of the First North American Green Roofs Conference, Chicago, May 2003. The Cardinal Group, Toronto. Moran, A., Hunt, B, Jennings, G. (2004) A North Carolina field study to evaluate green roof water runoff quantity, runoff quality, and plant growth. Greening Rooftops for Sustainable Communities, Proceedings of the Second North American Green Roofs Conference, Portland, May 2004. The Cardinal Group, Toronto. Peck, S. P., Callaghan, C., Kuhn, M. E. and Bass, B. (1999) Greenbacks from Greenroofs: Forging a New Industry in Canada. Canada Mortgage and Housing Corp, Toronto. Rowe, D., Rugh, C. & Durhman, A. (2006) Assessment of substrate depth and composition on green roof plant performance. Greening Rooftops for Sustainable Communities. Proceedings of the First North American Green Roofs Conference, Boston, May 2006. The Cardinal Group, Toronto. Van Seters, T., Rocha, L. & McMillan, G. (2007) Evaluation of the runoff quantity and quality performance of an extensive green roof in Toronto, Ontario. Greening Rooftops for Sustainable Communities. Proceedings of the First North American Green Roofs Conference, Minneapolis, May 2007. The Cardinal Group, Toronto.

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Engineering And Flood Management Iain Edmonds

Introduction • Surface water management plans. Flood risk management solutions need to be • Specific flood risk assessments. fully thought through, be appropriate for the • Planning Policy Statement No 25 – local environment, be cost effective and reduce Development and Flood Risk. the likelihood of flooding. This paper summarises the process of engineering a flood risk management solution, considers the aspects Community engineering flood risk that form part of the design process drawing on management solutions are only considered examples from within Yorkshire and looks to when all/some of the above plans/assessments the future and what is changing flood risk have identified a need. In this event there are a management. number of further studies which need to be undertaken before schemes proceed to There are many varied sources of flooding construction. Detailed below is a summary of and historically there has been no one body that the main elements of the process and these are has had overall responsibility for flood covered in more detail in the paper: management. For instance, flooding from ‘main’ rivers has been the responsibility of the • Pre-feasibility – this includes the preparation Environment Agency whereas flooding from of an outline hydraulic model, some drainage networks has been the responsibility preliminary site investigation and some of the water utility company and/or the local outline design. Pre-feasibility studies council. To complicate things further, riparian establish whether there is a viable owners are often not aware of their obligations engineering solution, the outline costs and and have allowed culverts and river training determine whether there is a cost beneficial walls to fall into disrepair. This lack of overall scheme. ownership is currently being investigated by a • Feasibility – this expands on the pre- number of ‘Integrated Urban Drainage’ (IUD) feasibility study, extends the hydraulic pilot studies which will, in one form or another, model, expands on the investigation of the be rolled out early next year. These IUDs look site and expands the quality of the spatial at the holistic problem and consider the overall data. The feasibility study also looks at the effect of heavy localised rainfall on rivers, engineering options for the solutions, drainage networks, sewers and the effect of expands on the sustainability and small scale obstructions, e.g. kerbs. The IUDs environmental impacts associated with the will identify measures which need to be taken scheme and identifies a preferred option to improve the situation. which is costed in order to allow a cost benefit ratio to be determined. In addition to the IUDs there are a number of other plans and assessments that are being • Outline design – the outline design expands used to aid better understanding of how river on the feasibility design taking it to a stage catchments respond to heavy rainfall and how where there is sufficient confidence in the new or re-developments will impact on the overall scheme to allow the costs to be local drainage environment. These are briefly identified and funding applications lodged. described in this paper and include: A key element of this section of the works is the identification of the ‘outcome measures’. • Catchment flood management plans. • Secure funding – either Defra or via local • Strategic flood risk assessments. levy.

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• Detailed design. plain, to a greater or lesser extent. This, • Construction. combined with the sudden deposition of materials during flood events, can result in variable ground conditions immediately When considering the engineering solutions adjacent to the current river alignments. This at pre-feasibility, feasibility and outline design variability of ground conditions makes design stage there are a number of issues which need and construction difficult. to be considered: There are generally three types of river • The solution needs to fit in with the local training structure that are commonly used, environment; there will be considerable local namely: opposition to providing an excessively high and visually intrusive river training wall • Steel sheet pile walls. when the open river aspect is important to • Reinforced concrete walls. the community. • Embankments. • The solution needs to be robust. • The solution needs to be safe to construct. Factors that need to be considered with these • Can flood storage be created upstream so basic structures are: that the flood waters are prevented from being passed downstream? • Health and Safety. • Can features causing flow restrictions, e.g. • Upstream storage. weirs, culverts, low bridges etc, be removed • Flood gates. or raised to prevent waters backing up • Provision for vehicle and pedestrian access. upstream of them? • Existing drainage discharging to river. • Are the proposed solutions sustainable? • Seepage. • Do the solutions resolve all the issues or are there other factors to consider, e.g. • Restrictions to normal ground water flow. environmental classifications, traffic • Environmental mitigation/enhancements. loadings, proximity of rail infrastructure, • Ground conditions. etc? The design criteria of such river training Flood Alleviation structures are generally such that they must meet a required standard of protection. This Flood alleviation schemes are generally required standard of protection will have been constructed in the urban areas as it is in these determined from the cost benefit analysis that areas where the greatest benefits can be was carried out at the feasibility stage of the realised. Historical development of these urban project. Examples of standard of protection areas has often concentrated around the rivers may be that the river training structure shall as these often formed the transport corridors meet the 1 in 100 year standard of protection with the neighbouring communities and the which is equivalent to a 1% chance of flooding means of disposing of waste. As part of the in any year. urban development, the river alignment has often been altered or the river culverted. These In addition to the standard of protection, the alterations and development in close proximity design criteria will often state that the leakage to the river are significant as the working areas and seepage through or under the river training and access to the river banks are often very structure must not cause flooding at ground restricted. To complicate things further, floor level in protected properties or at existing overtime rivers tend to move around the flood dry side ground level. The design criteria will also normally state that leakage and seepage

52 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 must not cause damage or deterioration to the river training structure such that substantial maintenance work is required. These criteria are satisfied throughout the design life of the scheme by ensuring the design is compliant with the relevant codes of practice, national and European standards, regulations and legislation combined with current good engineering practice. The Future Looking into the future there are a number of factors which are altering the way flood risk management is viewed, these include: • Political reviews undertaken following the summer floods of 2007. • Economic pressure and an increasing willingness to pay for flood risk management with the Association of British Insurers (ABI) putting pressure on the government. • Ecological factors such as climate change which are impacting on the environment. • Social issues which need to be addressed such as housing and social tolerance. • Technological advances in the provision of flood risk management solutions, flood forecasting and warning.

All these factors together with the Environment Agency Report of 2007, the ABI Report of 2007 and the Pitt Report of 2007 are suggesting the need for a national strategy plan for flood risk management and a need to raise the profile of critical infrastructure, etc. All these will, together with the IUDs, to a greater or lesser extent, impact on how flood risk management is handled in the UK in the future.

53 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008

Mere We Go Again Chris Gerrard

Introduction relevant here as the landscape will provide The story of the Fens is fascinating to historical wider socio-economic benefits, including flood ecologists and landscape historians. It is storage to protect local farmland and property. testament to the power of human endeavour The Great Fen Project is located where the over the natural landscape and a lesson in Whittlesey Mere was once found. It was the action and consequence. Hopefully the largest lake outside Cumbria prior to its experience of the past will help us make more drainage and is immensely important to the informed and longer lasting decisions for the heritage of the area. It is fitting that open water future. should be created at this site once again. The Great Fen Project is a landscape-scale Whittlesey Mere restoration project located in the western Fens Whittlesey Mere is thought to have begun to between Peterborough and Huntingdon (Figure form between 2,000-3,000 years ago. It was 1) and is just the latest of a series of dramatic formed as climatic changes caused a rise in sea changes to affect the area. The project will levels after the last Ice Age, preventing the restore 3,000 hectares of farm land into drainage of rivers into the sea. The subsequent wetlands and other habitats to protect the flooding created the Fens landscape, a mosaic important National Nature Reserves of of wetland habitats including reed beds, Woodwalton Fen and Holme Fen. It is a pasture, wet woodland and open water. In partnership between the Environment Agency, Cambridgeshire much of the land was covered Huntingdonshire District Council, Middle Level in a deep layer of organic peat soil, a fact that Commissioners, Natural England and the would be a constant concern for farmers and Wildlife Trust. drainage engineers alike. The mere’s natural environment was very important to the local The term ‘ecosystem services’ is used to economy, providing large numbers of wildfowl describe the various benefits semi-natural and fish, as well as raw materials such as reed ecosystems provide for society. The term is and sedge. The mere was also a source of recreation (publicly accessible greenspace, as we would call it today). The mere was famed for its skating and regattas (Figure 2) and people would travel from miles to come and watch and participate in the activities. By this time, the land around the Whittlesey Mere, and the mere itself, had become the last remaining large area of undrained fen. During

Figure 1: Great Fen Project Area. Figure 2: A Regatta on the Whittlesey Mere.

54 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 the sixteenth and seventeenth centuries the industrial drainage of the Fens had transformed the landscape from wetland wilderness to tamed farmland. This remarkable and ongoing undertaking has produced a significant proportion of the country’s best quality farmland. Had the mere survived a few more decades perhaps it would have survived to the present day. The certainty of higher profits meant its drainage was inevitable and this was completed in the early 1850s. Victorian historian W. H. Bernard Saunders wrote ‘…the soil was found to be rich, and largely impregnated with animal Figure 3: The Holme Fen Post. matter, so that the wind, which in the summer management by the network of Internal of 1851 was curling the blue waters of the lake, Drainage Boards and the Middle Level was, in the autumn of 1853, blowing in the Commissioners (MLC), which controls the same place over fields of yellow corn.’ main drains that typify the Fens. The ecological value of the mere was huge. Approximately 50% of the plants now extinct Woodwalton Fen and associated sites in Huntingdonshire were lost with the drainage Woodwalton Fen NNR is one of only three sites of the mere, or from Holme Fen which still in the Fens where the undrained landscape can suffers the effects of low water levels (Wells, be sensed (the others being Wicken Fen and 2003). Today over 99.9% of the Fens has been Chippenham Fen on the other side of the drained. county). It is one of the oldest Nature Reserves in Britain, purchased by Charles Rothschild in Because William Wells, the local squire who 1910 and now owned by the Royal Society of was one of the architects of the drainage, knew Wildlife Trusts. In order to best manage the site what would happen to the soil once it was it was agreed between the MLC and the Nature drained, he erected the Holme Fen Post to Conservancy (now Natural England, the site record the change. It was buried so that the top managers) to use the site as a flood storage of the post was at ground level. In that time the reservoir. This performs the important function ground level has dropped so that the top of the of keeping the reserve wet by maintaining a post is over 4m above the ground level today higher water table than would otherwise be (Figure 3). This soil is releasing huge quantities achievable. A clay bank was built around the of carbon dioxide into the atmosphere, contributing to climate change. The area that was once Whittlesey Mere is now the lowest lying ground in the country, which itself is in the Fens landscape, most of which is below sea level and needs pumping to remain adequately drained for agricultural purposes. There have been several major flooding events in the Fens including the devastating floods in winter 1947 and in 1953 when about 2,000 people lost their lives. That there has not been further flooding across large area of the Fens has been down to a small part Figure 4: The harvest of 1912 during one of the many floods that the fen has suffered. luck and a large part vigilance and good

55 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 fen to keep water levels high but also that in A considerable amount of research has been times of need, such as in 1998, the MLC can undertaken to place the project on a robust store floodwater on the reserve. Then the whole scientific footing. Eco-hydrological modelling reserve (208 hectares, 514 acres) was a metre has shown how the project will eventually deep in water. This important ecosystem service create large areas of reedbed, wet grassland, comes at a cost. The quality and quantity of fens and wet woodland and with the right water in these flood events is damaging the engineering can provide enhanced flood storage reserve. Woodwalton Fen is a Site of Special to continue to protect the local area. Whilst the Scientific Interest, Special Area of recreation of the Whittlesey Mere is not Conservation and a Ramsar site. These possible due to changes in local topography, designations put a legal duty on the site open water will be created where the mere once managers to ensure the site is in favourable dominated the landscape. The restoration will condition. A solution for this problem is provide new access to the countryside where required. very little currently exists. Restoration and ongoing management will prevent large Holme Fen should have been the fourth amounts of carbon dioxide from escaping into fragment of surviving ancient fen. However it the atmosphere and will also sequester is cut into four parts by agricultural drains that greenhouse gasses in the future. keep water levels in the reserve well below what they should be. Fens and raised bogs have Conclusions given way to Silver Birch woodland (visible The Great Fen Project is addressing socio- from the trains on the East Coast Main Line economic and environmental problems by between Peterborough and Huntingdon). The proposing that the land between the reserves be tiny areas of wetland that remain will disappear returned to a mosaic of wetlands and other unless the drainage can be reversed and water habitats. This will conserve the remaining, and put back into the system. significant, peat resource, create new areas to The extinction of the Large Copper butterfly store flood water and restore a huge area of in1864 was due to loss of habitat across its core wildlife habitat to be enjoyed by local people. range of the Fens and East Anglia. This habitat Since the project started in 2001, large areas of loss and fragmentation is a problem for mobile land have been purchased. By the end of 2008 species as suitable habitat becomes smaller in over 60% will be owned by a project partner, extent and separated by greater areas of thanks mainly to a Heritage Lottery Grant of inhospitable countryside. Climate change is £8.9 million, the largest heritage grant ever predicted to make this worse for many species. given in England. This will allow for the purchase and restoration of land and the Thus we have two hugely important nature provision of education and community reserves whose survival depends on the way activities to learn about and celebrate this water is managed around them. Climate change undervalued but remarkable landscape. brings greater uncertainties for the natural environment, threatening to accelerate problems Nature conservation has for a long time already experienced in the countryside. focused on small sites, protecting the best Imaginative solutions that make the best use of remaining places for wildlife. A key task for the land are required. Rainfall patterns are conservation movement in the future is to think predicted to change and this introduces another bigger and demonstrate the important driver for the Great Fen Project. Woodwalton ecosystem services offered by landscapes rich Fen is no longer thought to be big enough to in wildlife (Wildlife Trusts 2006). The Great provide an adequate level of flood water Fen Project shows how this can be achieved in storage. This creates an opportunity to provide practice. enhanced storage elsewhere, solving the problems encountered in the nature reserve.

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References Anon. (1998) Cambridgeshire’s and Peterborough’s state of the environment report 1998. Chapter 5 WATER, pp125-156, Cambridgeshire County Council.

Bronstert, A. (2003) Floods and Climate Change: Interactions and Impacts, Risk Analysis, Volume 23, No. 3, pp545-557.

Plate, E.J. (2002) Flood risk and flood management, Journal of Hydrology, Volume 267, Issue 1-2, pp2-11.

Wells, T.C.E. (2003) The Flora of Huntingdonshire and the Soke of Peterborough. Witley Press.

Wildlife Trust (2006) A living landscape. A call to restore the UK’s battered ecosystems, for wildlife and people. See www.wildlifetrusts.org.

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Policy And Farming Perspectives Of Flooding And Flood Risk Anna Hall Water Policy Adviser National Farmers' Union, Agriculture House, Stoneleigh Park, Stoneleigh, Warwickshire, CV8 2TZ

Introduction harvesting and planting as the ground was Flooding poses considerable challenges for waterlogged, housed livestock eating into rural and farming communities. Property, winter stocks of fodder, this combined with a livestock and livelihoods can be severely shortage of fodder from the floods has meant impacted at times of flood. Land and crops that fodder prices have increased dramatically cannot be insured from flood events, and so as that has had knock-on impacts to the livestock we have seen this last Summer, some farmers sector compounding problems this summer of have lost hundreds of thousands of pounds foot and mouth and bluetongue. worth of crop. Flood events can damage land Farming and Water for considerable time, contamination brought down by floodwaters can prevent crops from Farmers, particularly in low lying areas such as being grown or livestock grazed for many years parts of the East of England, are often the ones to come and is expensive to rectify, and land involved with water level management and flooded by the sea can be severely impacted by ensuring that towns and villages, as well as the salt. agricultural land, are protected from flooding. We have managed water levels for generations Summer 2007 saw severe flooding over to allow us to farm, to live and for transport, thousands of hectares of farmland, estimates and now we do the same to maintain habitats range from 17,000 to 60,000. Most farmers and biodiversity, so we must make sure that were affected by the weather in Summer 2007, even with climate change, that we are able to with widespread water logging of soils at a protect those things that are most important to critical time for harvest: for a few the us. consequences have been financially disastrous. The costs in the East Riding of Yorkshire area Climate change is predicted to bring greater where it is estimated that approximately 10,000 and more frequent extreme events but we must hectares was flooded in terms of lost income not forget that climate change is a global and accrued costs are in the region of £18m. phenomenon. We have seen food prices We have seen a range of impacts of the floods, increase recently, and this in many ways can be which came at the worst time for agriculture as related to weather events in the UK and fields were full of crops, livestock and when overseas. We must make sure we continue to be many operations on the land usually take place. as productive as we are now, or even more so The first impacts were the immediate impacts: with the uncertain future of climate change. this included livestock being drowned on the In the future, it may also become harder for floodplain, crops being damaged by the flood us to be able to rely on imported food and that and rescued livestock having to be moved into is why it is so important to protect our most housing. Longer term impacts include standing viable and productive land. In addition, in the water on fields causing crop and grass death UK and Europe, we have some of the highest and contamination of soil with floodwaters animal welfare, hygiene and environmental bringing downs contaminated material, debris standards in the world. Is it responsible for us and rubbish from upstream, which is left to the to obtain foodstuffs from places elsewhere that farmer to clean up once the flood waters have receded. Other impacts are the delays to

58 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 do not meet our standards, causing But, leaving land or watercourses ‘to nature’ environmental damage, suffering and perhaps will not produce the flood risk benefits we want result in greater greenhouse gas emissions? or desire. Leaving channels to silt up and vegetation to grow reduces the carrying In a context of climatic and energy capacity of the channel, and the conveyance uncertainty, we believe that it is in the strategic increasing the likelihood of flooding in the interests of UKplc that our best and most local area. This may be indeed one of the versatile land is protected from flooding and managed solutions to flood risk but it must be coastal erosion. Land is a finite resource, and designed to flood in a predicable way/in a once lost it loses it production capacity. We do managed way, in much the same way are hard not want to cut off our, and future generations’ defences were designed and maintained ability to adapt to global climate change. It is historically. If the land needs protecting from worth noting that some 57% of Grade 1 flood then the channel must be maintained to 1 agricultural land is below the 5m contour and ensure water can easily be conveyed away. the low lying land of the fens produces some 37% of the outdoor vegetables grown in Conclusions England2. We appreciate that in many areas no amount of However, the NFU recognises that we maintenance would have stopped the floods of cannot keep building higher and higher flood 2007 as this resulted from an exceptional defences to protect our land everywhere. The volume of rain, however free-flowing channels cost of doing so would be enormous and the could have made the recovery much faster, effort could prove futile, in the worst case giving water the ability to get away. Many of could cause knock on impacts elsewhere. We the crops were ruined, not from the flood itself therefore believe that all landscapes, both urban but the duration that the floodwaters were on and rural, have a vital role to play in flood risk the land, many weeks in some cases. Designing management and floodwater storage. In and creating flood storage areas will take a choosing which areas are designed for water Government commitment to do something storage we must exercise caution: They need to positive and support those whose land is be at the right location in the catchment and needed for these areas. Storing floodwaters on managed so they capture flood peaks at the land, to protect downstream villages, towns, right time; too early and the storage area will motorways, railways, critical infrastructure and be filled allowing the peak to continue prime agricultural land is a public service that downstream and flood and too late permits the is being provided by that landowner and this peak to pass and cause flooding. In some cases service needs to be appreciated. these flood storage areas may also have to be At present, it is feels as if agriculture is the pumped to be emptied following the floods, so poor relation as farmland is flooded by default they must be supported and well managed. as waters are channelled through urban areas They can support biodiversity but this should with flood defences, and in many instances not be at the expense of their primary function, much of the water is generated from developed flood risk management. The management of areas with acres of hardstanding generating floods will have benefits for biodiversity as runoff quicker than it would naturally otherwise those areas which we want to protect, as they have done. contain important species or sites that are highly biodiverse can also be protected. Flood We need more joined up thinking, with storage areas also should not be used to resolve solutions right throughout the catchment, flooding caused by poor planning and drainage appreciating that changes in land management, of new developments. be it rural or urban all influence flood risk.

1 MAFF 2000. Climate Change and Agriculture in the UK 2 Defra 2006. June Agricultural Census

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The Integration Of Nature Conservation And Flood Prevention Measures In A Mountainous Region H. Heilmeier1, E. Richert1, S. Bianchin1 , M. Merta2 and C. Seidler2 1Technische Universität Freiberg, AG Biologie/Ökologie, Freiberg, Germany 2Internationales Hochschulinstitut Zittau, Zittau, Germany

Abstract of floods (e.g. Bronstert et al., 2002). According to Blöschl et al. (2007) land use The potential of measures which integrate both exerts dramatic impacts on flooding especially flood prevention and nature conservation was at smaller catchment scales. In Central Europe investigated for two sub-catchments selected in mountainous regions with their usually small- the Weißeritz catchment (Eastern Erzgebirge, to medium-sized catchments are the sites where Saxony, Germany) which was heavily affected floods are usually generated. Land use change by the floods in August 2002. Changes of land from forests and grasslands to intensively use such as transformation of arable fields into managed arable fields also on steep slopes has grasslands, ecological transformation of forests, been discussed as an important factor complete afforestation, establishment of small increasing flood generation potential in landscape structures like hedgerows and mountainous regions. On the other hand, major restoration of rivers were in the focus of the capacities for water retention have been lost in project. the floodplains of the lowlands due to land For the sub-catchments a detailed survey of drainage, intensive urbanisation and river the present state with respect to landscape channelisation (Mant & Janes, 2006). ecology and hydrology via systems analysis The effect of these changes in the landscape and modelling was performed. Biotope types have become drastically evident during the and landscape structure were analysed and extreme floods in Central Europe, especially evaluated using criteria from nature Eastern and Southern Germany, Austria and the conservation on the one hand, and hydrology Czech Republic in August 2002. Heavy modelled by two tightly coupled models on the precipitation which reached 312mm within 24 other hand. A deficit and risk analysis was the hours in the upper ranges of the Eastern basis for the development of different land use Erzgebirge (Saxony, East Germany) caused scenarios, which were derived from a number floods in the Elbe and Danube catchments with of aims of high priority both from the flood maximum peak, e.g. in Dresden of 9.4m (i.e. prevention and nature conservation perspective. nearly 8m above average). The economic Results from this combined approach show that damages due to the floods amounted to more land use changes can substantially contribute than 10 billion Euros, and twenty people lost both to flood prevention and nature their lives in Saxony, fifteen in the Czech conservation. Republic. Keywords: Land use change, landscape These events reminded European society and ecology, conservation assessment, hydrological science that also industrialized countries are not modelling, river restoration safe from major disturbances due to extreme Introduction weather constellations, they may even become more frequent with possible climate change. On Flood prevention and nature conservation are the other hand, politics, administration and often considered to be incompatible. On the science became aware that technical approaches other hand, changes in landscape structure and alone can reduce damages by floods to a certain land use in the last decades have been degree only, but must be accompanied by flood discussed as possible factors increasing the risk

60 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 prevention measures integrating landscape (Mannsfeld & Richter, 1995). Presently a third management within whole catchments. of the Weißeritz catchment is covered by Therefore principles and methods from forests, mainly spruce monocultures. Almost landscape ecology and nature conservation half of the area is used by agriculture, with should be considered when designing measures agricultural crop land dominating in the lower to increase water retention capacity in a region. and middle ranges, grassland in the upper regions (Mannsfeld & Richter, 1995). These concepts were within the focus of the project “Flood Prevention and Nature The Eastern Erzgebirge can be considered as Conservation in the Weißeritz area” a hydro-geologic unit. Interflow plays an (“HochNatur”), funded by the German important role within the investigation area. Environmental Foundation (Deutsche However, within the middle and lower regions, Bundesstiftung Umweltschutz, DBU) in the arable land with silty soils shows bad response to the floodings in August 2002. The infiltration conditions, which in combination Weißeritz catchment in the Eastern Erzgebirge with the partly very steep slopes often results in was one of the catchments most heavily overland flow. The receiving streams, affected by the flood, causing major damages in dependent on soil moisture, respond very fast to the cities of Dresden, Freital and Tharandt, but precipitation events. also in rural areas and on infrastructure like roads and railway tracks. The HochNatur project aimed to design measures which integrate both flood prevention and nature conservation. Land use changes such as transformation of arable fields into grasslands, ecological transformation of forests, complete afforestation, establishment of small landscape structures like hedgerows and restoration of rivers were in the focus of the project. In the following results on the evaluation of various land use scenarios considering both flood prevention and nature conservation will be presented, using two sub-catchments with contrasting topography, soils, elevation, climate, land use and biotope patterns as an example. Investigation area The Weißeritz catchment (384km²) declines from about 900m above sea level (m a.s.l.) in the mountain ranges along the German-Czech border down to 200m a.s.l. in the northern foreland (Figure 1). The soils, which were Figure 1. Map of the HochNatur investigation area mainly formed on periglacial debris, are “Weißeritz catchment” and the two sub-catchments (SC) “Höckenbach” and “Weißbach” in the Eastern shallow and rich in skeleton, especially in the Erzgebirge (Saxony, Germany). upper areas. In the lower and middle area sandy loamy Cambisols are widespread, in the upper areas poor Podzols and shallow skeletic Umbrisols predominate. Silty Cambisols and Stagnosols have formed on loess. The valleys are usually characterised by holocene sediments

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Two sub-catchments, the Weißbach (WB, of aims of high priority both from the flood 630 to 800m a.s.l., 7.4km2) and Höckenbach prevention and nature conservation perspective (HB, 350 to 500m a.s.l., 16.7km2) were (Table 1). selected because of their contrasting topography and present land use. Due to the On the basis of these aims of high priority, complex relief shallow cambisols predominate the following major guidelines were derived: in the Weißbach sub-catchment. Apart from (1) land use changes predominantly on areas forests (24% of the total area), this sub- with fast runoff components, (2) transformation catchment is covered by grassland (42% of the of arable fields into extensively used area), which is mainly extensively used (33% grasslands, (3) extensification of intensively of the area). Especially the floodplain, but also used grasslands, (4) forest transformation and the slopes are characterized by a small-scale afforestation (according to potential natural mosaic of various endangered habitat types vegetation), (5) establishment of small such as extensively used mountain meadows landscape structures like hedgerows, (6) and reeds dominated by small sedges with a restoration of rivers and their floodplains. In large number of endangered species. In consideration of these guidelines and the contrast, the Höckenbach sub-catchment is detailed systems analysis of landscape ecology dominated by arable fields (69% of the area), and hydrology of the present state in the two whereas grasslands and forests occur on 6 and sub-catchments various land use scenarios were 13% only. The predominantly flat slopes are developed (see Table 2). strongly endangered by erosion. Habitats or The scenario “complete afforestation” was species relevant from a nature conservation kind of a reference scenario with respect to (1) perspective are very rare. the potential natural vegetation of the landscape as being closest nature according to the Methods naturalness criterion of the conservation Derivation of scenarios assessment at the habitat level and (2) assess the water retention capacity of a completely A detailed survey of the present state of the two forested landscape. The scenarios “arable field sub-catchments Höckenbach and Weißbach into grassland” and “ecological transformation with respect to landscape ecology and of forests” were developed in order to analyse hydrology via systems analysis and modelling the relevance of these land use changes from was undertaken using a method transferable to the agricultural and forest, i.e. landowners’ other mountainous regions (see below). Based perspective. For the scenarios “nature on these empirical data a deficit and risk conservation measures” and “flood prevention analysis was performed. This was the starting measures” land use changes were designed point for the development of different land use nearly exclusively from the perspective of the scenarios, which were derived from a number relevant guidelines. The last scenario attempted

Nature conservation Flood prevention Conservation/increase of species and Quenching of peak flood discharges habitat diversity Reduction of fast runoff components Conservation/increase of biotope (surface runoff and fast interflow) connections and landscape connectivity Increase of water storage capacity of the Conservation/development of habitat types landscape with high conservation value Increase of water retention in the floodplain Conservation/development of landscape Reduction of soil erosion appearance characteristic for the nature area

Table 1. Aims of high priority from the nature conservation and flood prevention perspective as the basis for derivation and assessment of land use scenarios in the HochNatur project.

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Scenario Abbreviation HB WB present land use pres - - complete afforestation c_aff 89.7 90.8 arable field into grassland a-g 69.0 16.3 ecological transformation of forests tr_for 12.6 24.3 nature conservation measures nat 83.7 53.8 flood prevention measures flood 82.2 51.8 combination of nature conservation and flood prevention comb 82.9 51.3 measures Table 2. Compilation of the land use scenarios analysed in the project “HochNatur” (“Flood prevention and nature conservation in the Weißeritz area”), their abbreviations and the area percentages affected by land use changes in comparison to the present state in the sub-catchments Höckenbach (HB) and Weißbach (WB). n. a. = scenario not analysed. to design land use changes which should serve does not yield any information about their demands both from nature conservation and spatial distribution and arrangement, structural flood prevention. composition of the landscape, and the diversity and complexity of the landscape as a whole Landscape ecology (Turner et al., 2001). Therefore an assessment The main focus of the ecological analysis was for the whole landscape through landscape on high-resolution biotope mapping and the metrics was necessary to analyse the structural assessment of the present state and the and biotope type diversity at the landscape developed scenarios. The assessment of the level. For this analysis the Shannon/Weaver various biotope types was done with the help of diversity index, the mean patch size index as three evaluation criteria, naturalness, well as the interdispersion/juxtaposition index, substitutability and rareness and endangerment which describes the spatial arrangement of the (Bastian & Schreiber, 1999; Figure 2). patches within the landscape, were calculated However, the assessment of biotope types only (Farina, 2000). In order to compare the

Figure 2. Procedure of the assessment of conservation value at the biotope and landscape scale for the present state and land use scenarios developed within the HochNatur project.

63 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 different land use scenarios with each other and employed to parameterise the afterwards the current state a ranking system was used. following runoff-precipitation models WaSiM- Within a last step the results were weighted ETH and SWMM (Rossmann, 2005), which according to the percentage of the area with were used to quantify the runoff of the medium to high conservation value (Figure 2). respective sub-catchment.

Hydrology Results The hydrological system analyses were based Landscape analysis and evaluation on the expert system WBS FLAB The two sub-catchments clearly differed in their (Zimmermann et al., 2001) and the present nature conservation value on a single precipitation-runoff model WaSiM-ETH habitat scale (Figure 3). Whereas areas with (Schulla & Jasper, 2006). The two models were very low conservation value prevailed in the coupled, which enables functional spatial agriculturally dominated Höckenbach sub- structuring of the catchment regarding the catchment in the lower ranges, areas with processes of runoff generation, as a basis for medium to high conservation value covered the quantitative modelling of runoff situations. more than 50% of the Weißbach sub-catchment Additionally, risk areas can be identified for in the higher mountain ranges. high water emergences. The various land use change scenarios which The expert system WBS FLAB (Expert involved large area proportions of the System – Area of Equal Runoff Components) catchments (cf. Table 2) affected the uses general available information about the conservation value similarly in both area (land use and vegetation, soil types or catchments: the complete afforestation scenario geology, stream network and digital elevation created exclusively sites with highest model) and subdivides a catchment into areas conservation value (apart from settlements not in which a certain runoff process dominates included in the measure), and transformation of (Merta et al., 2003). Here the quick runoff arable fields into grasslands increased the area generation processes were in the focus of proportion of sites with medium to high consideration for the high water emergences. conservation value to more than 80%. Due to Detailed information and parameter lists of the small percentage of area affected, maps, e.g. physical soil parameters, soil ecological transformation of forests yielded in horizons, rooting depth, root system structure small improvements from the nature and coarse root and fine root represented the conservation point of view only. The scenario factual knowledge of the expert system (Merta developed solely on nature conservation et al., submitted). The WBS FLAB results were guidelines yielded in lower proportions of areas

Figure 3. Area proportion of habitats with different nature conservation value (assessment of biotope types) for the present state and several scenarios developed for two sub-catchments in the Erzgebirge within the HochNatur project.

64 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 with high and highest conservation value to the present state. In contrast, ecological compared to the complete afforestation scenario transformation of forests, although affecting a due to its low scores especially in the criteria small area proportion only, had positive effects naturalness and substitutability for most of the especially on mean patch size and Shannon non-forest sites. Interestingly, the flood diversity index. Due to a number of measures prevention scenario had a positive effect in both like extensively managed grasslands and sub-catchments by reducing the area proportion ecological transformation of selected forests with low and lowest conservation value and with fast run-off components in the creating a large proportion of areas with highest agriculturally dominated Höckenbach sub- conservation value compared to the present catchment, the flood prevention scenario state (especially in the Weißbach sub- created biotope types which were not mapped catchment). A similar effect was achieved by in the present state and therefore increased the scenario combining both flood prevention landscape metrics scores (especially habitat and nature conservation (Figure 3). diversity and spatial heterogeneity) for this sub- catchment even more than the pure nature However, as explained in the Methods conservation scenario which created a more section, the assessment of biotope types on a uniform pattern of biotopes with high per site basis only does not consider their conservation value. Contrarily, in the Weißbach spatial distribution and arrangement, the sub-catchment with its already higher structural composition and the diversity of the proportion of sites with high conservation value landscape as a whole. Landscape metrics flood prevention measures had a negative effect evaluating the structure and complexity of the compared both to the present state and nature landscape mosaic both for the present state and conservation measures. As expected, the the scenarios yielded in assessments which scenario combining both flood prevention and differed strongly from the conservation nature conservation yielded in landscape scores assessment on the habitat scale. The complete intermediate between the two specialised afforestation scenario which resulted in scenarios for both sub-catchments (Figure 4) maximum area percentage of highest conservation value achieved the lowest scores Integrating results from the habitat based for landscape metrics, due to its loss in habitat conservation assessment into the landscape diversity and spatial heterogeneity (Figure 4). evaluation by weighting the landscape metrics Similarly, transformation of - mostly large - scores by the percentage of area with medium existing arable fields into grassland reduced to highest conservation value yielded, with the landscape diversity and complexity compared exception of the complete afforestation scenario

Figure 4. Scores from the nature conservation assessment by landscape metrics for the present state and several scenarios developed for two sub-catchments in the Erzgebirge within the HochNatur project.

65 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 in the Weißbach sub-catchment, in higher (33%) compared to the Höckenbach sub- scores for the overall nature protection criteria catchment in the lower ranges (16%). Slow for all scenarios analysed (Figure 5). Ecological runoff components like delayed interflow which transformation of forests did not show marked originates mainly from areas with minor slopes improvements due to the low percentage of and loess or deep soils below extensively used forests, especially in the Höckenbach sub- meadows occurs more frequently in the catchment. On the other hand, transformation Weißbach compared to the Höckenbach sub- of arable fields into grassland can improve catchment (29% versus 9%). The time lag in conservation value of an agriculturally these lateral water flows is due to the intense dominated landscape like the Höckenbach sub- well-structured root system which increases the catchment considerably. Similarly, measures porosity of the grassland soils and therefore directed especially to prevention of floods, due their water storage capacity (Merta et al., to generation of new habitat types, will have submitted). more positive effects in a landscape dominated by agriculture and settlements. Interestingly, the The various land-use scenarios generally scenario combining measures directed both to yielded in the reduction of fast runoff nature conservation and flood prevention components (surface runoff, saturation overland resulted in pronounced improvements in both flow and quick interflow) compared to the sub-catchments, which is partly due to a large present state on a larger area proportion in the proportion of area affected (cf. Table 2). Höckenbach versus the Weißbach sub- catchment. This is especially true for the Hydrological analysis and assessment scenario “transformation of arable fields into grasslands”. Due to the high percentage of The present state of the agriculturally agricultural crop land (69% of the total area) in dominated Höckenbach sub-catchment is the Höckenbach sub-catchment, the area with characterised by potential overland flow from fast runoff can be reduced by 40% compared to areas with bad infiltration capacity especially less than 20% in the Weißbach sub-catchment on loess soil (43% of the sub-catchment area), (Figure 6). The scenarios “complete whereas this fast runoff component is of minor afforestation”, “nature conservation measures”, importance (19%) in the less intensively “flood prevention measures” and their managed Weißbach sub-catchment (Merta et combination all reduce the area with fast runoff al., submitted). On the other hand, quick components in the Höckenbach sub-catchment interflow which occurs particularly on steeper by approximately 45% versus 30 to 35% in the slopes and forested shallow soils (mainly Weißbach sub-catchment (Figure 6). Land use spruce monocultures) is more abundant in the changes in these scenarios enclose a large area Weißbach sub-catchment in the upper ranges

Figure 5. Results from the evaluation of land use change compared to the present state according to nature protection criteria in relative scores with respect to the scenario “nature conservation measures” as a reference for for two sub-catchments in the Erzgebirge within the HochNatur project. For abbreviations of scenarios refer to Table 2.

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Figure 6. Results from the hydrological assessment for for two sub-catchments in the Erzgebirge within the HochNatur project. Numbers indicate the reduction of area proportions with fast surface and subsurface flow components in comparison to the present state. For abbreviations of scenarios see Table 2. proportion of the sub-catchments, therefore Höckenbach sub-catchment being more they are very effective concerning flood pronounced than in the Weißbach catchment prevention in these regions. In contrast, the (Figure 7). However, not all of these scenarios scenario “transformation of forests” enhances improve the nature conservation value of the the actual state in the Weißbach sub-catchment sub-catchments. Especially complete by less than 6%, because of the steep slopes afforestation does not yield in higher and the shallow soils in this area. At such sites conservation value, yet may even decrease it a transformation of spruce monoculture shows for the Weißbach sub-catchment with its minor effects only. In the Höckenbach sub- already very high conservation status and catchment there was no effect in this scenario at diversity of the present biotope types, since all due to the currently small percentage of biotope diversity and spatial heterogeneity will forests. be lost. In the agriculturally dominated Höckenbach sub-catchment transformation of The model WBS FLAB analyses the runoff arable fields into grasslands, which affects large generation processes and assesses the area proportions, shows nearly equal effectiveness of all scenarios in a qualitative improvements compared to the present state way whereas the precipitation-runoff-model both from the nature conservation and flood WASIM-ETH calculates the discharge in the protection perspective. Whereas the scenarios river quantitatively. The results of the flood prevention and complete afforestation are application of both models WBS FLAB clearly more relevant for hydrological (reduction of areas with fast runoff processes than for conservation purposes, the components) and WASIM-ETH (reduction of nature conservation scenario affects both aims peak discharge) were significantly correlated (p nearly equally. The same is true for the scenario < 0.05; Merta et al., submitted). combining measures directed both to nature In sum, from the flood protection point of conservation and flood prevention (Figure 7). view especially the scenarios with large Importantly, measures aimed at flood changes in land use (complete afforestation, prevention synergistically interact with nature flood prevention measures, nature conservation conservation (habitat and species diversity, measures, combination of nature conservation connectivity), landscape conservation and and flood prevention measures) resulted in aesthetics (tourism and recreation potential) and marked improvements in comparison to the soil protection (erosion). Moreover, these present state, with the effects in the measures contribute to a balanced regional

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Figure 7. Combined assessment of land use scenarios with respect to flood prevention and nature conservation developed for two sub-catchments in the Erzgebirge within the HochNatur project (for abbreviations of scenarios refer to Table 2). hydrological budget, which can mitigate Landscape elements preventing fast runoff negative consequences of summers with low components and therefore flood peaks like precipitation. grasslands or small pathways have been largely destroyed or changed in the last century, Conclusions whereas arable fields and settlements have The integrative assessment of scenarios of land increased, especially in the Höckenbach sub- use changes for two sub-catchments in a catchment in the lower ranges of the Eastern mountainous region has shown that by defining Erzgebirge, as a comparative survey of the guidelines aimed at both flood prevention and historical and present landscape structure in nature conservation measures can be derived both sub-catchments by Grosch (2006) showed which yield in significant improvements for (Table 3). Hedgerows which may not only both goals. Even land use changes that were reduce surface flow of water, but also soil designed exclusively from the nature erosion, are nearly completely absent from the conservation perspective and therefore two sub-catchments. In the Weißbach sub- emphasized biotope diversity and landscape catchment some hedges were planted in the last heterogeneity can contribute to flood years to reduce wind erosion. prevention by improving infiltration of water In a similar way, rivers have been into the soil and reducing fast runoff dramatically changed by channelisation, components (Merta et al., submitted). On the accompanied by other major changes in the other hand, land use changes directed associated floodplain in the last centuries. River exclusively at flood prevention can improve the and floodplain restoration measures like conservation value of the sub-catchments. This meanders, riparian buffers and creation of water is due to a reduction in area proportions of retention areas as designed by Dzianisava arable fields and larger proportions of forests (2006) for the Höckenbach sub-catchment were close to nature, extensively used grasslands and investigated for their potential to decrease peak small landscape structures, which increase discharges and flow velocities. For the section landscape diversity and heterogeneity. of the Grundbach, a tributary of the Höckenbach, immediately before entering the village of Ruppendorf restoration measures

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Höckenbach Weißbach 1890-1945 1999 1890-1945 1999 Grassland (area percentage) 18.7 6.3 19.0 43.0 Arable fields (area percentage) 60.2 69.2 57.7 27.2 Settlements (area percentage) 8.1 10.0 5.0 11.2 Hedgerows (m ha-1) 0.0 0.0 1.1 1.8 Pathways (m ha-1) 50.7 12.7 57.2 36.8

Table 3. Change in landscape elements from 1890 to 1999 in the Höckenbach and Weißbach sub-catchments in the Eastern Erzgebirge (Data from Grosch, 2006). could reduce peak discharges by about 25% and Acknowledgement flow rates by more than 50% (Table 4). This The HochNatur project was funded by the shows the high potential of flood prevention German Environmental Foundation (Deutsche measures on the basis of principles from Bundesstiftung Umwelt). restoration ecology and nature conservation. The effect of land use changes heavily depends on the specific conditions of the References landscape such as the presence of habitat and Bastian, O. and Schreiber, K.-F. (1999) Analyse landscape elements with high relevance for nature conservation, and such as vegetation und ökologische Bewertung der Landschaft, structure (density, height, root depth etc.) with 2nd edition. Spektrum Akademischer Verlag, relevance for flood prevention (Merta et al., Heidelberg, Berlin. submitted). Therefore results from the individual scenarios developed for the two sub- Blöschl, G., Ardoin-Bardin, S., Bonell, M., catchments cannot be transferred to other Dorninger, M., Goodrich, D., Gutknecht, D., catchments. On the other hand, the methods Matamoros, D., Merz, B., Shand, P. and developed for the assessment both from the nature conservation and flood prevention Szolgay, J. (2007) At what scales do climate perspective can be transferred to other regions variability and land cover change impact on as long as necessary data such as a digital flooding and low flows? Hydrological landscape model, land use type and distribution Processes, 21, 1241-1247. and soil characteristics are available. Bronstert, A., Niehoff, D. and Burger, G. (2002) Effects of climate and land-use change on

Present State After Restoration Discharge HQ 5 (L s-1) 2200 1600 Discharge HQ 100 (L s-1) 5400 4000 Flow velocity HQ 5 (m s-1) 2.18 096 Flow velocity HQ 100 (m s-1) 2.17 0.95

Table 4. Discharge and flow velocities of the Grundbach in the Höckenbach sub-catchment. Values were modelled for a precipitation event of 10 min for with a reoccurrence interval of either 5 (HQ 5) or 100 years (HQ 100) for the Grundbach in its present state and after restoration measures as suggested by Dzianisava (2006) using the programme SWMM (unpublished results from G. Hammer, Büro für Hydrologie und Bodenkunde, Dresden, Germany).

69 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 storm runoff generation: present knowledge and both nature protection and flood prevention. modelling capabilities. Hydrological Processes, Soil and Water Research. 16, 509-529. Rossmann, L.A. (2005) Storm Water Dzianisava, N. (2006) Renaturierungskonzept Management Model - User’s Manual, Version für einen Mittelgebirgsbach aus Sicht des 5.0, EPA, United States Environmental Naturschutzes und des Hochwasserschutzes am Protection Agency, EPA/600/R-05/040. Beispiel des Höckenbaches/Erzgebirge. Schulla, J. and Jasper, K. (2006) Model Diploma Thesis, AG Biologie/Ökologie, TU Description WaSiM-ETH. Internal report, IAC, Bergakademie Freiberg. ETH Zürich, 174 pp. Last update December Farina, A. (2000) Landscape Ecology in Action. 2006. Kluwer Academic Publishers, Dordrecht. Turner, M.G., Gardner, R.H. and O’Neill, R.V. Grosch, J. (2006) Geschichte der Landnutzung (2001) Landscape Ecology in Theory and des letzten Jahrhunderts im Einzugsgebiet der Practice, Springer–Verlag, New York. Weißeritz und in ausgewählten Zimmermann, S., Töpfer, J. and Peschke, G. Teileinzugsgebieten. Undergraduate Thesis, AG (2001) A knowledge-based system to improve Biologie/Ökologie, TU Bergakademie Freiberg. the processing of distributed precipitation- Mannsfeld, K. and Richter, H. (1995) runoff models. In: Runoff generation and Naturräume in Sachsen. Forschungen zur implications for river basin deutschen Landeskunde, 238. Zentralausschuss management/modelling, Proceedings of the für deutsche Landeskunde, Trier. IAHS/ICT/ICSW Freiburg workshop October Mant, J. and Janes, M. (2006) Restoration of 9-12, Freiburger Schriften zur Hydrologie, 13, rivers and floodplains. In: Van Andel, J., 175 – 182. Aronson, J. (eds.) Restoration Ecology, pp. 141-157. Blackwell Publishing, Malden, MA (USA). Merta, M., Seidler, C., Uhlenbrook, S., Tilch, N., Zillgens, B. and Kirnbauer, R. (2003) Das Wissensbasierte System FLAB als Instrument zur prozessbezogenen Raumgliederung von mesoskaligen Einzugsgebieten. In: Kleeberg (eds.) Klima-Wasser-Flussgebietsmanagement – im Lichte der Flut. Beiträge zum Tag der Hydrologie am 20/21 März 2003 in Freiburg. Forum für Hydrologie und Wasserbewirtschaftung, 1, 171 – 178. Merta, M., Seidler, C., Bianchin, S., Heilmeier, H. and Richert, E. (submitted) Analysis of land use change in the Eastern Erzgebirge regarding

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Developing Decision Support For The Use Of Non- Structural Responses In Flood Risk Management Helen High1, Jonathan Cooper1, Oliver Grant2, Kevin House2 [1] JBA Consulting, Skipton, UK [2] Environment Agency, London, UK

Introduction reduced by the implementation of non- structural measures. As such, as part of the London and the Thames Estuary are currently TE2100 project, a decision support tool is being protected to a high standard of flood defence. developed which will: However, rising sea level, changes in fluvial flows due to climate change, increasing • provide information on vulnerability, hazard development in the floodplain and decaying and associated consequence over the Thames defence performance arising from asset aging Estuary; and or shrinking maintenance budgets mean that • guide decisions on the use of non-structural flood risk is increasing and improved protection responses as part of an integrated flood risk will be required. management approach. The Environment Agency’s Thames Estuary 2100 project (TE2100) is developing a flood The tool will show spatially where measures risk management plan for London and the are not appropriate, through to types of areas Thames Estuary for the next 100 years and is where measures are potentially applicable. exploring a range of options for an integrated Those areas which come out of this test as flood risk management approach. As part of potentially appropriate for non-structural this approach, there is increasing emphasis on responses can then be looked at in more detail the use non-structural responses (NSRs) which in terms of community make-up and their could supplement or reduce the need for capability to reduce consequence. structural measures. Taking a non-structural route to flood risk management will rely on a To date, a screening tool as been developed more community-centred approach that which includes multiple GIS data layers recognises the particular circumstances of (termed GIS analysis tool here) and a decision community and social groups. However, the screening framework. This abstract describes effectiveness of many non-structural measures the development of the tool and how it has is reliant on the community responding been applied to screen NSR applicability at a appropriately and is currently severely limited PMU level so that the Environment Agency can by low risk perception and lack of flood include applicable measures in their Floodplain experience. Hence, in reality, and as a result of Management Option for the Thames Estuary. the heavily defended nature of the Thames Estuary, flood risk in London and the Estuary The final tool will provide the basis for will be managed by a combination of structural engagement with stakeholders about non- and non-structural responses. structural measures (including planning authorities, emergency planning Category one In order to understand the effectiveness of responders and other decision makers with the non-structural measures and therefore make responsibility of managing flood consequence) more informed choices as to the most and will feed into flood management planning applicable response to flooding, decision at each level from high level strategic flood makers need to know what the potential social management planning decision making through and economic consequences would be as a to site master planning. result of a flood event and how this could be

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Decision Screening Framework management response (to move existing The responses listed below have been screened property out of the floodplain) will need to be for their applicability in Thames Estuary flood considered. This screening can also work in risk management. reverse or in an alternative order, for example, where a land management solution is Manage flood event considered as the most appropriate response but Shelter in place cannot be delivered on social, environmental or cost grounds. The focus will be on Evacuation enhancement from civil contingency measures Manage (future) flood losses which will be critical to the effectiveness of all Land use management non-structural responses and should be carried out as baseline good practice. Punitive Insurance premiums Land use planning GIS Analysis Tool • Development control to limit development GIS layers illustrate vulnerability and hazard • Building design conditions so that areas can be categorised Flood proofing where NSRs are not appropriate, through to Increased insurance/compensation provision types of areas where theses responses are potentially applicable. The main tool inputs (see Figure 1) include a The screening framework illustrates the series of GIS layers which illustrate: situations using a series of vulnerability and hazard thresholds at which NSRs are • The nature of the hazard; applicable. This approach screens out those • Social vulnerability (social groups); and areas most obviously unsuitable for non- • Building vulnerability (those properties that structural responses such as rapid inundation house vulnerable population, may be areas and those areas where flood depths pose difficult to evacuate, need to remain significant loss of life in vulnerable operational or have the potential to cause communities. For those areas remaining, the hazard if flooded). following was assessed. • The size of the area affected by flooding and Hazard information included in the GIS at what depth analysis tool is provided from the Thames • The number of people involved (both Estuary TE2100 Flood Risk Model in the form residential and workplace population) of probabilistic depths for the TE2100 High Plus Climate Change Scenario under current • The potential to evacuate to higher ground conditions. Vulnerable buildings data has been and the make-up of the community: drawn from recent JBA projects ‘Receptors • Social groups and their distribution; and Vulnerable to Flooding Database’ and ‘TE2100 • Buildings that are difficult to evacuate, serve Flood Vulnerability Baseline Assessment’. the community or pose a hazard. In order to assess social consequence or • Speed of onset (i.e. flood warning) impact at different levels of flood hazard in a • Duration simple and clear way, a measure of • Frequency of flooding vulnerability (which takes account of the different types of social vulnerability) has been The screening approach is hierarchical, for developed. Two vulnerability indices have been example, if managing the flood event is not developed using principal component analysis – applicable then a land use planning response (to a financial deprivation index and a health prevent building in the floodplain) or a land use index. The two vulnerability indices characterise the levels of social vulnerability

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Figure 1. Conceptual model of tool inputs

(low, medium, high) in relation to the financial risk, where the combination of receptor and health status of the population in London vulnerability and flood hazard brings the real and the Thames Estuary. The health index social dimension of flood risk to that required provides information on where the most by the Floods Directive. The integration of vulnerable groups are in terms of their vulnerability and modelling information fills a capability to respond and health implications gap within flood risk management which has during and following the flood. The financial often been overlooked and is very important for index provides information on where the most more equitable flood risk management and vulnerable groups are in terms of potential consideration of recovery issues. economic loss and difficulty in returning to normality post flood. NSR Applicability in the Thames Estuary The social side of this analysis is vital as A non-structural response is considered to be social impacts account for a significant amount applicable where it is feasible that the response of loss during flood events and impacts heavily could be implemented and, if it were on the cost and rate of recovery. This implemented, would potentially reduce risk. information is therefore particularly important This does not guarantee that the action would in the appraisal of flood risk management be effective in reducing loss or increasing measures and options as social impacts have, in resilience. The performance of responses will the past, not been included in a detailed enough rely on a number of conditions on which way owing to their complexity and difficulty of relatively little information is available, for quantification. This is considered to be a major example the full implementation of the policy step in the identification of areas of significant option (e.g. adoption of contingency plans) or

73 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 the appropriate response of the affected population (e.g. take up of and response to flood warnings, adoption of individual resilience measures). An evaluation of such performance issues is being carried out at a PMU scale using Event Tree Analysis alongside the literature to assess how NSR components will operate. This information, derived using the improved knowledge on receptor vulnerability, will lead to the development of a practical, illustrative tool which provides analysis of flood risk and the capability of NSRs to reduce risk at a community-level. The outcome of the screening is therefore made up of a range of responses that are potentially applicable in each PMU. Further screening of responses requires more detailed local assessment including localised risk and public/stakeholder acceptability issues. As the Environment Agency does not have statutory responsibility for many of the non-structural responses being considered, it will need to work closely with partners and stakeholders to share information about the new approach, understand and explore stakeholder priorities and concerns and agree the applicability of proposed responses. Acknowledgements The authors wish to acknowledge the assistance of the following people for their contribution to the project: Sue Tapsell and Edmund Penning- Rowsell at FHRC and Paula Orr and Clare Twigger-Ross at Collingwood Environmental Planning.

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Slowing the Floods in the U.K. Pennine Uplands…A Case of Waiting for Godot? S.N. Lane Institute of Hazard and Risk Research, Durham University. [email protected]

Abstract partitioning of precipitation between overland The possibility that management of the rural (fast) and subsurface (slow) flow, under the landscape might provide a means of reducing hypothesis that land management that reduces downstream flood risk remains the topic of the generation of fast flow will lead to less both extensive research and debate. Here, I downstream flood risk; (2) increasing the identify some of the difficulties associated with storage of runoff within the catchment, under establishing such a link. Using the c.120-year the hypothesis that retention of water will lead instrumented flood record of the City of York, I to reduced downstream flood risk; and (3) show that land management changes in the reducing the speed of conveyance of runoff upstream catchments of the Swale, Ure and within the drainage and channel network, under Nidd are plausible reasons as to why there is a the hypothesis that slower conveyance will lead pattern of increasing magnitude and frequency to greater flow attenuation and hence reduced of flooding at York. However, I also show that downstream flood risk. Such groupings are these flood patterns correlate with other drivers somewhat artificial: the use of a rural of flood risk, such as the changing frequency of floodplain to slow conveyance, for instance, dominant flood-producing weather types. I use may involve allowing fields to flood, which this evidence as the basis of a wider discussion may result in both storage and reductions in of the difficulties of using data to identify conveyance. A recent review of the potential possible rural land management impacts upon role of rural land management in reducing flood risk and to consider the very severe flood risk (Lane et al., 2007) noted that storage difficulties that catchment-scale flood risk measures are already routinely considered as modelling presents. Much of this relates to the part of flood risk reduction strategies, primarily complex interaction of a number of controls through the designation of floodplains as that almost certainly means that whether or not washlands, but also in other ways such as rural land management impacts upon flood risk through using small dams and bunds in upland depends upon the rainfall event, the catchment catchments (e.g. White Cart Water, Glasgow). and the scale of analysis. It follows that the Such strategies, particularly floodplain storage search for a general conclusion as to rural land schemes, can be readily assessed through management impacts is not a meaningful existing flood risk assessment methodologies scientific quest and a clear answer is unlikely (e.g. addition of storage zones to one- ever to emerge. dimensional hydraulic models). What remains a much more elusive goal is Key words providing demonstrable scientific evidence that Flood risk management, rural land changing rainfall partitioning or reducing management, York, drainage, uplands, flooding conveyance speed has an impact. Whilst there are both historical and current experiments at Introduction the scale of individual fields and sub- Measures for flood risk reduction associated catchments (e.g. the 18km2 Pontbren catchment, with the management of rural landscapes can currently the focus of the U.K.’s Flood Risk be grouped into three broad sets of measures Management Research Consortium), (Lane et al., 2007): (1) changing the extrapolating their results to very large

75 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 catchments of 100s or 1000s of km2 is The changing magnitude and necessary in order to assess the extent to which frequency of extreme flood events: the field and sub-catchment scale impacts scale up City of York to impact upon downstream communities. There are two primary upscaling approaches The City of York lies on the River Ouse and that can be adopted: (a) the analysis of receives inputs from three key sub-catchments historical flood events and their interpretation (the Swale, the Ure and the Nidd), and two with respect to possible drivers; and (b) minor catchments (the Foss and the Kyle) catchment-scale hydrological modeling. In this (Figure 1). Thus, the hydrology of the Ouse is paper, I use evidence from research into flood heavily influenced by the behaviour of history in the City of York: (1) to show the upstream river systems that extend into the difficulties in using historical records to resolve South Pennines and the Yorkshire Dales. In land management impacts upon changing flood addition to these upstream influences, the risk; (2) to discuss the extent to which installation of Naburn Weir in 1759, at the modeling might provide a suitable alternative; downstream end of the study reach, resulted in and (3) to provide a broader perspective that a profound change in river behaviour. Prior to questions the extent to which the hypothesis this installation, the Ouse from Myton-on that rural land management activities might Swale (the confluence of the Ure and the impact upon flood risk is a meaningful one to Swale) through York was affected by tidal pose. I conclude by arguing that even if the cycles. scientific debate can be resolved, rural land Each of the three main sub-catchments (the management measures are fundamentally Swale, the Ure and the Nidd) rise in the centre different in nature to other flood reduction and on the Eastern edge of the Yorkshire Dales measures (such as flood defences) and that they and Southern Pennines and enter relatively should be treated as complimentary measures well-developed valley systems. The basin rather than compared as alternatives. geology comprises: (1) millstone grits and carboniferous limestone in the upper

Figure 1. The Ouse catchment upstream of the City of York, northern England.

76 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 catchment; (2) a piedmont zone consisting of catchments, with the exception of the Ure, Permo-Triassic magnesium limestone and where there is significant amount of woodland mudstone; and (3) the Vale of York, comprising adjacent to river channels, especially in the Quaternary glacial and alluvial deposits lower catchment. The North-East part of the overlying Permo-Triassic Sherwood sandstone. Swale catchment also has significant woodland The Kyle and the Foss, as shorter rivers that cover. The upper parts of the major sub- drain the Vale of York, have relatively under- catchments are predominantly moorland or developed and basic drainage networks. The pasture, and are influenced by two key main sub-catchments have drainage networks agricultural changes in recent history: (i) that reflect the overall relief of each sub- upland land drainage associated with gripping; catchment. In the upper part of each catchment, and (ii) changes in stocking densities. The first these are strongly dendritic. Each river system of these really began from about 1944 and the follows the main valley. As it approaches the introduction of grant-in aid for land drainage lower gradient sections of the Vale of York, the that extended through to 1968 (Longfield, rivers start to meander, and notably the Swale 1998). The major increase in stocking density and the Nidd. This characteristic has largely begins around 1982, and it has been suggested ended by the confluence of the Swale and the that this resulted in a 40% increase in sheep Ure, and the Nidd and the Ouse. numbers in the Yorkshire Dales to 1995 (Sansom, 1996). Law et al. (1997) provide an overview of the hydrology of the Humber catchment, including The reason for focusing on the Yorkshire the Yorkshire Ouse. Mean annual precipitation Ouse is that it has a long duration of exceeds 1750mm per year in the upper part of hydrological records in the City of York itself. the Ure, and 1500mm per year in the upper Of most importance is the ‘Viking’ record of parts of the Swale and the Nidd. The rainfall water level in the centre of the city which decreases most rapidly in the Swale, followed provides a daily record of maximum water by the Ure and the Nidd, with less than 750mm level from 1878 to present. As a record of water per year in the Vale of York, including the Kyle level, it is a true record of the occurrence of and Foss catchments. This emphasises the flooding (i.e. flooding occurs when water levels importance of sub-catchment hydrological exceed a critical defence threshold) and it is controls upon flows in the Ouse as this is where also of very long duration. However, it has two most precipitation falls. Indeed, there is problems. First, the relationship between commonly a delay of anything up to a few days discharge and water level also depends upon between the timing of peak rainfall in the sub- river channel conveyance, which essentially catchments and the timing of peak flows in the describes the ease with which water is Ouse at York. This emphasises that transferred through the river network. understanding the York flood record requires an Commonly, if the conveyance of the river is emphasis upon the upstream contributing sub- reduced, then the water level associated with a catchments, rather than the more local urban given discharge may be increased. Hence, a and lowland arable and pasture environments in record of water level will be a record of both the vicinity of York, although the latter do changing precipitation, upstream land provide a potential flood storage function. management, etc. as well as local conveyance, as controlled by the shape of the channel, local The three main sub-catchments are river defence activities and the resistance to associated with a transition in land-use from flow associated with the roughness of the moorland in the upper catchment, through channel boundary and the level of vegetation in pasture on well-drained upper slopes, at lower the channel. For instance, if there is elevations on the valley sides and in the valley aggradation of the river-bed, due to sediment bottoms, through to arable where the valleys delivery, then the magnitude of the water level widen into the Vale of York. There is very little reached for a given flow may be greater. in the way of woodland cover in any of the

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Similarly, if the amount of bank or in-channel analyses. The threshold was set at 8.058m, vegetation increases, then the water level commonly taken as the threshold at which associated with a given flow will commonly be flooding begins in York. Lane (2003) checked higher. Second, water level changes are not a the extent to which this is a reliable surrogate linear function of flow changes. The rate of for changes in flow by relating water levels at change of water level depends upon the rate of York to discharges at Skelton, for all flow change of flow, but also section shape, water peaks above the 8.058m threshold. This surface slope, bed roughness, etc. Once restricted analysis to the pre-1992 flows based flooding starts, the rate of water level increase upon the stage-discharge record. Results will commonly fall, as more of the increase in suggested a possible decrease in water levels flow is accommodated by increases in wetted associated with a given flow since 1969, width. Thus, the water level record is affected implying that the water level record will be by strong non-linearity, which means that its weakly biased towards reduced flood frequency magnitude must be interpreted with caution. and magnitude through time. Thus, whilst the Viking record is long, it may be contaminated by effects that are not Evidence of change connected with upstream land management or Figure 2 shows the number of floods per climate change. decade (defined as a peak over a threshold series) and an annual maximum flood series, The main alternative to using a water level for the York water level recorder (‘Viking’). record is to use a discharge record. A digital The results are quite dramatic, suggesting a record of discharge is available for Skelton, just progressive increase in both the frequency and upstream of York, from 1969 to present. the magnitude of flood events as a function of However, this record presents problems. First, it time, notably from the 1940s. However, they is of shorter duration. In searching for trend in also reveal: (1) significant between-year a flood record, as the record length is reduced, variability in the magnitude of the annual so trend may be artificially introduced where maximum flood (Figure 2a); (2) organisation the record starts in an exceptionally dry period into runs of years with higher annual maximum or artificially hidden where it starts in an flood magnitudes (e.g. the 1960s) and lower exceptionally wet period. Second, up until annual flood magnitudes (e.g. the early 1970s) 1992, it was based upon a stage-discharge (Figure 2a); and (3) evidence that floods as relationship. A continuous record of water level large as those in recent living memory (1982 is transformed into a continuous record of and 2000) can be found historically (1888 and discharge using a relationship based upon point 1947). The first point that emerges from this measurements of discharge for known water record is the sensitivity of interpretations to the level. Thus, up until 1992, the record is duration of the record inspected. Robson (2002) essentially a record of water level, expressed as shows how what appears (visually and a discharge, and the same conveyance effects quantitatively) to be trend in series like the described above may apply. However, a greater annual maximum flood, depends upon the problem exists. In 1992, a continuously duration over which the assessment is made. recording ultrasonic gauge was installed. This Records that start in the 1960s and 1970s tend provides a more reliable measure of discharge to show trend because of a relatively dry period and has demonstrated that the peak flows at the start of this period (Robson, 2002). This estimated using stage-discharge curve are over- reflects wider realisation that the timescales estimated. Thus, the flow record contains a required for detecting change in hydrological break point in 1992, making its use for the record may be significantly longer than the period 1969 to present problematic. timescales over which the drivers of those Given the above, the focus of this analysis is changes have been responding (e.g. Wilby, the Viking record of water levels, based upon 2006). This is particularly the case for runoff peak over threshold and annual maximum flood records (Robson, 2002), not least because many

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Figure 2a and 2b. Records of the number of floods per decade (as a peak over threshold) and the annual maximum flood, for the ‘Viking’ record of water level in the City of York. river catchments are heavily regulated, making three are of particular importance. First, since identification of atmospherically-driven runoff the 1940s, much of the Swale, Ure and Nidd signatures particularly difficult (Hannaford and sub-catchments have been drained, using open Marsh, 2006). This emphasises the value of drains or grips, which are channels up to 0.45m long records like ‘Viking’, especially when deep, and ranging from 0.50 to 0.75m wide at what matters for flood risk is water level, which the surface to 0.15 to 0.25m wide at the base may not be only a function of river discharge. (Robinson, 1990). Drain spacing and The second point is somewhat in contrast to the arrangement varies widely such that the density findings of Robson (2002), which was that varies greatly, as does their spatial arrangement there were no significant trends in key flow within the landscape (Lane, 2003). Generally, characteristics for the River Ouse at York. This gripping was introduced to drain peaty soils to may be because of the short duration of the improve grazing quality and for grouse Skelton record, but it may also be because of shooting (Robinson, 1990). More than 50% of the extreme uncertainty associated with the parts of the Nidd and the Swale were subject to magnitude of the largest flood events. If peak gripping between 1940 and 1965 (Robinson, flows pre-1992 are over-estimated using the 1990), with very high rates (affecting more than stage-discharge, then this will reduce the 7km2 per year) in the 1940s and 1950s. Rates identifiability of trend in the complete series dropped off in the 1960s, but then rose again in since 1969. It emphasises the need to inform the 1970s before declining in the 1980s. analyses of flow records with carefully The functional process that ties gripping to synthesised historical and contextual flood risk generation is more complex than information on the reliability of those records. might at first be thought, not least because The rural land management evidence as to the effects of gripping upon hypotheses downstream flood risk is contradictory. Conway and Miller (1960), for a Northern England peat In the simplest of terms, and upon first covered catchment, found that open drainage inspection, rural land management in the increased peak runoff. Robinson (1986) studied Yorkshire Dales could be a plausible hypothesis 0.5m deep, 4.5m spacing drains set in peat for the trends shown in Figure 2. There are land varying in depth from 0.5 to 3.0m in Coalburn, management changes that could have Northern England, with turf ridges in between. contributed to all three of the runoff altering The drains increased stream network length 60 measures identified in the introduction, and fold. The study compared two time periods,

79 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 pre-drainage (1967-73) and post-drainage grips or small grip networks. At the catchment- (1974-78), and found that despite similar scale, the location of the drainage activity is a annual rainfall totals and seasonal distributions crucial variable. The effect of grips will be to of rainfall, the 90% daily flow excedance was change which parts of the catchment deliver doubled post-drainage. This was attributed to storm runoff when. If drainage is located such significant increases in the percentage of rapid that it delivers water from late responding parts runoff and a reduction in the time to peak. of the catchment more quickly, then this may However, the drains had a restricted lateral actually contribute to increase the catchment effect, as had been observed by Hudson and flood peak. Similarly, if the drainage is located Roberts (1982) and Robinson and Newson such that it delivers water from parts of the (1986). Further, the effects on peak flows were catchment that normally respond early, causing only significantly different for intermediate them to respond even earlier, then this may flood flows, not for larger flood flows, reduce the catchment flood peak. Lane (2003) including the mean annual flood. Robinson has shown that the relative timing of flood (1990) reached similar conclusions for peaks from the Swale, Ure and Nidd basins is a Blacklaw Moss in southern Scotland, with second order explanatory variable (after flow markedly shorter hydrograph response times magnitudes) of the size of flood flows at York, post drainage. and if grips have caused a systematic change in flood peak timing, then this could lead to These observations contrast with those that higher flood flows for a given rainfall event. suggest that drainage has reduced peak flows because it provides greater opportunity for A second plausible hypothesis for the water storage and hence reduced stormwater increases in flood magnitude and frequency at production. Burke (1975) found that drains led York relates to the increases in stocking to the progressive drying of peat, with water densities that have been observed since the tables 0.20m below surface in winter and 1970s, largely associated with European Union 0.45m below surface in winter. It was argued agricultural policies. Up until the early 2000s, that this lowering of the water table would these have subsidised farmers on a per capita increase water storage so reducing flood peaks. basis with the result that stocks have risen, in Similarly, although for backfilled rather than some cases very sharply. The basic hypothesis open drains, Newson and Robinson (1983) that stocking densities might impact upon flood found for peaty gley and podzol soils on generation relates to a range of processes. Rhiwdefeitty Fawr, Plynlimon, Wales that APEM (1998) note that high stocking levels: drainage lengthened the duration of storm (a) may lead to biomass loss, which reduces runoff and reduced peak flows due to lowering evapotranspiration rates, so maintaining high of water tables. levels of soil wetness, and also reduces root depth which reduces infiltration into the soil; Thus, grips could both reduce flood risk by and (b) leads to increases in surface soil hindering the generation of rapid runoff through compaction, which also reduces infiltration. enhancing soil storage (i.e. a change in Sheep are of particular concern. Betteridge et partitioning) but also increase flood risk by al. (1999) demonstrated that different types of allowing for the more rapid connection of cattle had different effects upon the soil rainfall to the river network (i.e. a change in surface: cattle caused upward and downward connectivity). The obvious question is which of soil movement leading to high levels of soil these two effects dominates, and under what disturbance, whereas sheep caused more circumstances. Newson and Robinson (1983) surface compaction. These observations are note that the effects of grips upon flood flows supported by a wealth of studies from a range will depend upon soil type, location of the grip of different environments. Much of the early within the drainage system, and the nature of research was conducted in rangeland type of the drain. Indeed, too much grip research has environments (e.g. Rhodes et al., 1964; Rauzi focused upon empirical studies of individual

80 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 and Hanson, 1966; Gillard, 1969; Langlands across whole fields where slope allows). These and Bennett, 1973). Langlands and Bennett results were used to assess changes in standard (1973) explored rangelands with different percentage runoff at the catchment scale and stocking densities reported a positive the authors suggested increases in runoff of relationship between soil bulk density and between 0.8% and 9.4% for the Ouse system as stocking density and negative relationship a result of soil degradation. Although the between soil pore space and stocking density, assumptions behind these data need careful leading to lower infiltration rates. This was exploration, and the propagation of error attributed to trampling but also the puddling associated with their derivation is also required, action of raindrops as they hit soil that had a they indicate the extent to which land greater probability of being exposed due to management may have a catchment scale over-stocking. Gifford and Hawkins (1978) for effect. More recent studies (e.g. Owens et al., rangelands, also found that ungrazed infiltration 1997; Greenwood et al., 1998) have rates were statistically different from grazed demonstrated that reducing stocking densities infiltration rates at the 90% level. However, leads to the long term recovery of infiltration most of this difference was attributed to heavy rates. However, changes in standard percentage grazing rates as opposed to moderate/light runoff do not necessarily translate into changes grazing. Observations that high stocking in flood peaks at the catchment-scale, notably if densities change soil surface properties and the catchment is already well-saturated or if hence infiltration rates have been extended to intervening attenuation effects are important. include studies of runoff. Branson and Owen (1970) found a statisitically significant The third major group of changes are relationship between the percentage bare soil associated with the management of the Ouse and annual runoff on the basis of seventeen floodplain upstream of the City of York. From sites in a semi-arid sub-alpine region. They the 1940s onwards, farmland upstream of York noted the relationship was strongest in the was progressively defended using low impact spring due to greater livestock trampling plus levée systems, commonly set back from the the effects of winter grazing before regrowth river by a small distance, and also accompanied began again. Similarly, Owens et al. (1997) by an expansion in agricultural underdrainage reported a reduced proportion of rainfall (Longfield and Macklin, 1999). In landscape occurring as runoff as a result of reducing terms, prior to the development of these stocking densities. defences, the water level (and hence the river flow) required for the onset of flooding would The above studies suggest that increases in be much lower than today. With greater transfer stocking density will change the partitioning of water to the floodplain, the riparian corridor between overland flow and through flow, and should have led to significant flood wave hence have the potential to change the ease attenuation, although there are no studies that with which floods are generated. There is some have as yet addressed the extent of this impact. restricted a priori support for the idea that With loss of attenuation, the magnitude of flood rising stocking densities in the 1970s and 1980s flows at York could be much larger. in the Yorkshire Dales may be contributing to the increasing magnitude and frequency of Rural land management and the flood events. Research commissioned following problem of serial correlation the November 2000 flood events within the The above discussion identified three Ouse system (Holman et al., 2002) suggested hypotheses that might have contributed to the that 4.6% of sampled sites were severely evidence of changing flood magnitude and degraded (sufficient to enhance runoff to cause frequency shown in Figure 2. Indeed, the three widespread soil erosion that is not confined to changes described have timings that match well wheelings/tramlines) and 36.1% of sites were with the flood records. But, this is where the highly degraded (sufficient to enhance runoff problems begin. Unfortunately, a range of other

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20 10 0 -10 -20 -30 year -40 -50 -60 -70 Cumulative deviation from average

number of SW, W, C, and CW days per CW days and per C, SW, W, of number -80 1860 1880 1900 1920 1940 1960 1980 2000 2020 Hydrological year

Figure 3. The analysis of Lamb weather types for the City of York. The four weather types (south-westerly, westerly, cyclonic and cyclonic-westerly) have been identified as responsible for almost 80% of flood events at York (Longfield and Macklin, 1999). Here, the average number of these four types per hydrological years is subtracted from the number recorded for each year and the deviations are cumulated. Rising parts of the curve show more flood generating weather types than average, falling show less. flood drivers are also correlated with the management impacts, or any other kind of changing flood record, including records from signal, including climate change, must be point rain gauges. For instance, Fowler and treated with some caution. Kilsby (2003) note a two-fold increase in the magnitude of extreme rainfall for parts of the Complexity in the flood system and U.K. Longfield and Macklin (1999) note that the problem of data availability 79.7% of documented flood events (before In identifying serial correlation amongst a 2000) in the City of York are associated with number of possible flood drivers, I have begun just four of the Lamb (1972) weather types: to unpack the complex nature of the flooding westerly, cyclonic, cyclonic-westerly and south- system. Figure 4 expands upon this complexity westerly. Figure 3 shows the cumulative by identifying a number of factors that cause us deviation from the average number of days per to think very carefully about the potential role year with these types of weather. There is a of rural land management in flood risk remarkable level of agreement with the overall reduction. On the left hand side of the diagram patterns shown in Figure 2b, with fewer floods is the simple assumption behind empirical per decade in period when there is fewer of testing of the three hypotheses regarding land these weather types than average. Associated management impacts, identified in the with the positive twentieth century trend in the introduction. The discussion of floodplain magnitude and frequency of flooding at York is management introduced the idea that also a trend towards weather types that are conveyance might impact upon observed flood more dominant contributors to flood risk. The magnitude and frequency. The discussion of fact that there is such a strong correlation with serial correlation noted changing rainfall weather types, which are themselves characteristics and weather types. To these, the autocorrelated (albeit spuriously) with changes diagram adds two other broad areas that will in land management, means that simplistic determine how land management changes inspections of runoff records for land might impact upon flood risk management. The first recognises that our conceptualisations of

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Land Management Activity (e.g. Husbandry and Land livestock, arable) cropping practice (e.g. Management timing, intensity, Change Land Preparation (e.g. under-drainage) rotation)

Catchment context (e.g. soil and rainfall characteristics) Rainfall partitioning Rainfall amount, Catchment structure effects seasonal distribution (e.g. drainage and intensity density, location) Runoff timing effects Catchment arrangement Weather type and (in relation to Runoff routing tracking of weather precipitation gradients, effects systems other sub-catchments)

Upstream Flood conveyance magnitude and frequency Local conveyance The Flood system

Figure 4. A conceptualisation of the flood system for comparison with the serial correlation approach. the nature of land management are often much land management might impact upon flood risk more simplistic than is likely to be the case in is one that is beyond scientific investigation practice. For instance, gross data on changing because it is meaningless without reference to stocking densities, hide much more complex the particular catchment being considered at a within-year and between-farm variability in particular point in time. how those stock are managed, such as in relation to over-wintering, field rotation and There is no doubt that at least some elements within land holding variability in how land is of assessing the land management hypotheses used and treated (e.g. improved). The second are impacted upon by issues associated with introduces the importance of the catchment as data availability. In a conventional experiment, conditioning the effects of land management, each of the factors in Figure 4 would be including soil type, but also more complex perturbed, whilst others are held constant, and processes associated with the arrangement of a the associated impact upon flood magnitude catchment in response to the typical tracks of and frequency determined. In a more storms across a drainage basin and hence the sophisticated experiment, there might be some sequencing of where it rains when. Taken with form of joint factor perturbation. By assembling atmospheric variability and the importance of enough instances of the phenomenon (in this conveyance impacts, it becomes clear that case, the incidence of flooding at York) and attempts to use data to identify land then quantifying each of the relevant factors, management impacts may be confounded by then multivariate analysis may be used to distill the multivariate controls upon the flood the core drivers of the system. With so many generation process (Figure 4). Two different potentially controlling variables, the number of interpretations follow: (1) interaction between flood incidents required is likely to run to at these variables make identification of a land least two orders of magnitude. The problem management signal that is distinct from the may be broken down somewhat, allowing some noise introduced by other processes especially progress: for instance, Lane (2003) reported on difficult, but in theory, proper design of data principal components analysis on the thirty collection systems might allow such a signal to largest flood events at York, which when be identified; and (2) the hypothesis that rural combined with additional flow data from the

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Swale, Ure and Nidd, was used to show that the Authority until the late 1980s, when the relative time of basin response explained some National Rivers Authority took over of the variability in flow magnitude at Skelton. responsibility. As the public utilities were progressively squeezed under the spending The Lane (2003) work was based upon restrictions of the early and mid-1980s, so the records for gauges towards the downstream end frequency of ‘sampling’ (i.e. chart changing) of each of the relevant sub-catchments. The was reduced to make the record almost logical next step would be to explore the extent valueless by the mid-1980s. The creation of the to which the relative timing of these sub- National Rivers Authority resulted in a catchments could be traced back to catchment- progressive improvement in management of the scale land management changes. What is resource until, with creation of the Environment ultimately a reductionist approach to the Agency, the quality of management question ought to become easier, as the shift for deteriorated. Management of this resource a search for explanation moves upstream, to appears to have much more to do with political smaller and generally more homogeneous sub- and economic processes as they impact upon catchments in more upland environments. institutions than it has to do with elements of However, when we get into upland research design or good scientific practice. environments, there tends to be severe data With the development of digital data logging, availability issues: we simply do not collect the the need to visit gauges repeatedly is reduced, kind of data necessary to do this more upstream but this does not eliminate these sorts of analysis. The structure of rainfall recording has problems. Data storage is finite, and if not been designed with any sort of scientific downloading doesn’t occur sufficiently experiment in mind. The majority of records frequently, the data gets over-written. During are linked to either: (a) water resource the Foot and Mouth Disease crisis of 2001, the management, and notably potable water supply Environment Agency placed a blanket order on (e.g. they are found at reservoir non-essential field visits, such that many upland impoundments); or (b) where they can provide data recorders were not visited and data gaps sufficient warning to downstream communities, appeared. This was applied regardless of through telemetry, of an impending flood event. whether or not a gauge was within a restricted There are even fewer instances of long-term area. It is understandable from the perspective maintenance of water level or flow recorders in of the Environment Agency, which has to upland environments. Such data collection is maintain a good relationship with land expensive and requires a long-term managers. Any form of apparently unnecessary commitment to maintain data collection. access in relation to such a sensitive issue could However, such data collection is commonly have left the Environment Agency with difficult exposed to changes in scientific priorities. publicity problems, regardless of any actual Figure 5 shows the time between chart change risk. It is much less understandable from the for an upland stage recorder in the Yorkshire perspective of generating long-term high Dales. Up until the growth of digital data quality data from which to test hypotheses logging in the 1990s, chart recording was the regarding the effects of upstream land use upon major way in which long term water level flood risk. The length of record required to test records were obtained. The barrel in each the land management hypothesis, as with the recorder commonly would rotate such that one climate change hypothesis (Wilby, 2006), is week would be completed within one rotation. likely to be many decades requiring long Replacement of the chart, refreshment of the records for analysis. If the impacts of rural land ink and recalibration, is normally required management measures upon flood risk vary every two weeks in order to maintain the between catchments, then we will need such record. Up until late 1983, the Buckden long records in every candidate catchment. recorder was well-maintained. Responsibility for this rested with the Yorkshire Water

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60 50 40 30 20 10 0 Period to next sample (days)

Year

Figure 5. The number of days between changes of the chart and resupply of the ink for the Buckden recorder of water level on the River Wharfe, Upper Wharfedale, North Yorkshire.

Modelling as an alternative to the particular basins?. The first is essentially a analysis of historical data question of science. The second is a necessary response to an affirmative answer to the first. The alternative to relying upon data is to develop models that are capable of testing land There is now a long history (> 40 years) and management impacts. In theory, models allow also a well-developed critique (e.g. Oreskes and the kind of experimentation that is simply not Belitz, 2001) of the use of modelling in possible with extant, or even specially- hydrology. Central to the critique is the severe designed, datasets: it is possible to simulate the dependence of hydrological models upon a effects of different drivers in isolation and in system that is never perfectly specified by combination upon flood risk. Indeed, decisions available knowledge: the problem is seriously over current flood risk management are heavily under-determined. Here, knowledge includes: reliant upon models, both hydrological (such as (1) the perceptual understanding of what we the Flood Estimation Handbook, Institute of think matters to the flood system; (2) the Hydrology, 1999) and hydraulic (and notably conceptual understanding, or physics, necessary flood routing and inundation models). There is to translate our perceptions into mathematical much innovation in the modelling of rural land models; (3) the data necessary to provide management impacts. For instance, O’Connell boundary conditions to those models; and (4) et al. (2007) trace ‘packets’ of water across the parameters and processes that are landscapes and into predicted hydrographs to introduced into the model through the chosen see which runoff source locations have physics or necessitated by simplifications to contributed to the hydrograph peak. In turn, the that physics. There are five broad areas of geographical locations of the sources that critique of hydrological modelling: (a) the contribute the runoff peak can become the unresolvability of different model focus of testing possible land management configurations (Beck’s (1987) non- impacts with the aim of attenuating identifiability or Beven’s (1993) equifinality), downstream hydrograph response. Two often bound up with severe uncertainty in important questions then need to be asked: (1) model predictions; (b) the failure of models to do models sustain the argument that rural land ‘travel’ beyond the specific places or time management impacts upon downstream flood periods for which they have been developed risk?; and (2) can those models be used to and parameterised (e.g. Konikow and develop strategies for rural land management in Bredehoeft, 1992); (c) the lack of agreement

85 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 over what constitutes a reasonable set of model rural land management impacts upon the River predictions (Oreskes and Belitz, 2001), often Parrett and concludes that land management cast as a lack of standards in modelling (e.g. was having no impact upon flood risk. Lane and Richards, 2001; O’Connell et al., 2007); (d) the inadequacy of the measurements The interesting aspect of these two studies is available to resolve different model not the studies themselves, but the ways in formulations; and (e) the problem of applying which they are reviewed in Environment of modelling processes with a scale range of Agency (2007) and then presented in very different ways. In relation to the PDM work on c.107m2 (from an upland drain less than 1m wide to a catchment with a drainage area of the Ripon Multi-Objective project, it notes (p9, my emphasis in bold): “The Ripon Land 1000s of km2). The scale issue represents a particular problem because the evidence of land Management Project used scenarios to use management impacts upon rapid run off represent plausible changes to the land generation is more clear cut at the plot scale management or land use in all or parts of the (O’Connell et al., 2007). However, as a result Ripon catchment, targeting the three main rural of the processes like attenuation and sub- land uses in the catchment, moorland, improved catchment interaction, these plot scale effects grassland and arable. The impact of the may not necessarily still be detected at the proposed land management changes were catchment-scale. represented in simple 1-D rainfall-runoff models by altering parameters affecting the Despite the lack of a clear academic rate of runoff, soil moisture storage and consensus as to the most appropriate approach hydrograph timing.” The PDM approach is to modelling rural land management impacts, noted to have important weaknesses (p10): (1) consultants are being called upon to develop Scale issues - Land use change modelling is land management strategies for particular river undertaken at a sub-catchment scale and does catchments and this is proving to be the cause not take account of more localised changes; (2) of some controversy. Take the following Underlying science issues - Land use changes evidence from an internal report of the are simulated by making changes to parameters Environment Agency’s Delivering Space for within the Flood Estimation Handbook (FEH) Water project (Environment Agency, 2007). method, which provides only crude assessment The report compares two contrasting sets of of surface runoff impacts; and (3) Limitations results for the role of rural land management in in model input data quality and setup (e.g. reducing downstream flood risk. The first inadequate rainfall data, limited numerical comes from the Ripon Multi-Objective project, information about field drainage systems, poor based on the Skell and Laver catchments that knowledge of the underlying geology, limited drain into the River Ure. This project used a information on the hydraulic structures and soil Probability Distributed Moisture (PDM) Model characteristics). In contrast (p10, my emphasis that transforms input rainfall and potential in bold), the physically-based approach is evapotranspiration into an outlet discharge, described as have an underlying science that ‘is conceptualising the hydrological cycle as a generally considered to be more robust for this series of stores and transfers. The modeling approach (in comparison to the 1-D approach showed that the worst case land degradation at Ripon) because surface, subsurface and scenario led to increased peak flows in Ripon groundwater processes are better represented (20% for 1 in 10 year floods, 10% for 1 in 100 throughout the catchment using an array of year floods) and that the best case scenario for grid cells.’ There is no comparable critique of improving land management would reduced the River Parrett modeling in the report, even peak flood magnitudes by c.8%. The second though two-dimensional physically-based used a two-dimensional (i.e. spatially explicit) models have similar underlying science issues physically-based hydrological model to explore (e.g. how do you simulate a land use change in a meaningful way in the model?) and certainly

86 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 the same data availability issues. Even if the methodology used for hydrological elements of physics provides a better theoretical the analysis, one that has proved remarkably representation, the actual representation is only robust for about thirty-five years. The question as good as the data available to drive the that emerges, and which urgently needs physical processes. Acquiring spatially research, is the extent to which opinions on distributed information on the kinds of rural land management have become encoded parameters that will drive model response (e.g. to the point that the link to flood risk soil depth, saturated hydraulic conductivity and management is being socially-excluded. its variation with depth) is still almost impossible for anything more than the plot- More data, better models or a chaotic scale. Understanding the uncertainty in these conception? models is especially difficult because of the If we put the arguments above to one side, and large number of model parameters, coupled to accept that either more data or better models their computationally intensive nature. Multiple might actually be forthcoming, I think we are model runs really need the kind of high still left with a more fundamental problem in performance computing resources still only relation to rural land management impacts upon really found in universities. I am not arguing flood risk: it is what social scientists have that these are worse than approaches like the called a ‘chaotic conception’ (Sayer, 1992). PDM approach: rather that similar critiques of Sayer (1992, 138) defines chaotic conceptions physically-based models can also and should as ‘bad abstractions’ in which the indivisible is also be made. arbitrarily divided to create new lumpings of There are two important observations that processes and properties that are unrelated and, follow from what is described above. First, in the words of critical realism, ‘inessential’. even if a scientific case can be established for Following Sayer’s argument, the association of incorporating rural land management in flood land use management with flood risk is risk reduction, we are some way off from perfectly legitimate in descriptive terms. having suitable models that can be used by However, it is not legitimate to assign consultants to factor rural land management explanation to such an association, as, quite processes into decision-making. If there is no simply, the same land use management activity general relationship between land use cannot always be taken as having the same management and flood risk, models will need flood impact. As an example, consider the issue to be applied on a catchment-by-catchment of gripping. Whilst the study of a grip may basis. Thus, models suitable for use outside of allow a general conclusion to be reached about an academic context will be required. Second, the local impacts of that grip upon water and potentially more seriously, there is an balance and the timing of delivery of water element of hubris in the way in which the PDM from that grip to the drainage network, two and physically-based models are evaluated in important steps need to be taken to move from the above report. This may not be intentional the general observation of local runoff impacts and simply reflect an inadequate understanding to a general observation of flood risk impacts. of the limits of physically-based modeling. A First, the impact of that grip will depend upon less benign interpretation might be that the where it is within a sub-catchment. Gripping findings of the Parrett study fitted more with that is closer to the headwaters of a sub- broader opinion in circulation regarding the catchment may indeed deliver water more role of rural land management in flood risk quickly to the drainage network, and be a cause reduction. It is perhaps ironic that in almost all of flood risk. Gripping closer to a sub- flood risk assessments currently undertaken by catchment outlet, however, may actually U.K.-based consultants, the Flood Estimation enhance attenuation effects, and reduce flood Handbook method that is part of the critique of risk. Hence, as the spatial scale of enquiry is the PDM model remains the primary changed, so any possible generalisation will need to change: conclusions reached for a

87 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 single grip may not apply to a whole grip responsibility for their effective functioning network, let alone an entire sub-catchment. As rests with a single competent authority (e.g. the spatial scale of enquiry is increased, so the long-term maintenance of a flood defence role of other factors will become more levée); and/or (2) responsibility for action rests important. Similarly, there is a greater with direct flood victims (e.g. installation of probability that the effects of grips will become boards or sand bags to prevent flood water either counter-acting or synergistic, so making entering in a house). As an alternative, rural the conclusions difficult to generalise from land management would require many individual grip studies as well as from individuals to act, most of whom have no direct catchment-scale empirical generalisation. responsibility for preventing downstream Second, the effect of a grip may vary in time, flooding (e.g. farmers, at least under such as in relation to the direction that rain- conventional flood risk policy regimes), let bearing systems follow when moving across a alone the kind of incentive to act that comes sub-catchment, which controls when rain enters from being the potential victims of flooding. the grip, and hence whether the enhanced For a downstream flood victim, there is no connectivity it causes either increases or comparison between a conventional flood reduces downstream flood risk. The kind of embankment, maintained by the Environment generalisation that comes from the descriptive Agency, and the diffuse, uncertain land association of land management with flood risk management responses of a series of land has no explanatory power as the impacts of owners. Recommending the latter instead of the gripping cannot be separated from the nature of former will inevitably lead to controversy and the flood event being considered. If the is likely to remain socially uncertain however association between rural land management and scientifically certain the evidence to sustain it flood risk is indeed a chaotic conception, not might become. only will it take some time for us to have sufficient data necessary to reach a definitive Where rural land management measures conclusion, but a definitive conclusion, as with might interface with conventional flood defence Godot, may never come. measures will be through statistical generalisations of flood magnitude and Conclusion: moving flood risk frequency. Rural land management measures management upstream may eventually be shown to change the shape of flood duration curves in some situations and The immediate conclusions from this paper are so change flood return periods. Policy on flood three-fold. First, the hypothesis that rural land defence (e.g. PPS25, DCLG (2007)) is largely management impacts upon flood risk is not one cast in terms of flood zones where the return that is well-resolved by available data. Second, period of a given flood defines the kind of we do not have a consensus, in academic let development that is permissible in a particular alone delivery terms, upon the kinds of models place as well as the kind of measures that needed to test the hypothesis. Third, the statutory bodies like the Environment Agency hypothesis itself may never be resolved in a and Flood Defence Committees should general sense as a result of the sensitive consider. Rural land management measures will dependence in space in time upon the findings never provide the level of protection associated that arise. It is not actually a meaningful with conventional flood defences. The key hypothesis to investigate. hypothesis to investigate is whether or not the My final point is the need to think carefully progressive agricultural deintensification of about what a rural land management based large areas of river catchments, the social and flood mitigation strategy might involve, even if economic implications of doing so aside, might these issues could be resolved. Most traditional contribute to reducing the burgeoning cost of flood defence schemes have two important flood risk management associated with characteristics (Lane et al., 2007): (1) conventional flood defences through reducing

88 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 the level of protection necessary for Burke, W. (1975) Effect of drainage on the downstream flood exposed communities. Of hydrology of blanker bogs. Irish Journal of course, other benefits might accrue such as in Agricultural Research, 14, 145-62. relation to water quality or ecosystem function. However, and ironically, given the statutory Conway, V.M. and Miller, A. (1960) The way in which we define levels of protection in hydrology of some small peat covered terms of statistically averaged return periods, catchments in the Northern Pennines. Journal such a reduced level of protection might of the Institute of Water Engineers, 14, 415-24. actually translate into greater exposure to Department of Communities and Local flooding for downstream communities if rural Government (2006) Planning Policy Statement land management measures have an impact that 25: Development and Flood Risk, HMSO, is contingent in space and time and not always London, 43pp. guaranteed or as expected. Environment Agency (2007) Delivery of Acknowledgements Making Space for Water: HA6 Catchment Scale This paper has developed from work Land-Use Management; HA7 Land undertaken as part of NERC Grant Management Practices – Interim Report. NER/D/S/2000/01269/2, was stimulated by my Environment Agency, September 2007, 54pp. own experience of living with floods and has Fowler, H.J. and Kilsby, C.G. (2003) benefited from my subsequent involvement in a Implications of changes in seasonal and annual number of flood-related projects, notably the extreme rainfall. Geophysical Research Letters, OST’s Flood Foresight project. 30, 1720. References Gifford, G.F. and Hawkins, R.H. (1978) APEM (1998) The impact of grazing and Hydrologic impact of grazing infiltration: a upland management on erosion and runoff. critical review. Water Resources Research, 14, Environment Agency Research and 305-13. Development Technical Report P-123, Gillard, P. (1969) The effect of stocking rate on Environment Agency, Bristol, 42pp plus botanical composition and soils in natural figures. grassland in South Africa. Journal of Applied Beck, M.B. (1987) Water quality modelling – a Ecology, 6, 489-97. review of the analysis of uncertainty. Water Greenwood, K.L., Macleod, D.A., Scott, J.M. Resources Research, 23, 1393-442. and Hutchinson, K.J. (1998) Changes to soil Betteridge, K., Mackay, A.D., Chepherd, T.G., physical properties after grazing exclusion. Soil Barker, D.J., Budding, P.J., Devantier, B.P. and Use and Management, 14, 19-24. Costall, D.A., (1999) Effect of cattle and sheep Hannaford, J. and Marsh, T. (2006) An treading on surface configuration of a assessment of trends in UK runoff and low sedimentary hill soil. Australian Journal of Soil flows using a network of undisturbed Research, 37, 743-60. catchments. International Journal of Beven, K. (1993) Prophecy, reality and Climatology, 26, 1237-53. uncertainty in distributed hydrological Holman, I.P., Hollis, J.M. and Thompson, modelling. Advances in Water Resources, 16, T.R.E. (2002) Impact of agricultural soil 41-51. conditions on floods – Autumn 2000. Branson, F.A. and Owen, J.B. (1970) Plant Environment Agency R&D Technical Report cover, runoff and sediment yield relationships W5b-026/TR, Environment Agency, Swindon, on Mancos Shale, Western Colorado. Water 30pp. Resources Research, 6, 783-90.

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Hudson, J.A. and Roberts, G.A. (1982) The Law, M., Wass, P. and Grimshaw, D. (1997) effect of a tile drain on the soil moisture The hydrology of the Humber catchment. content of peat. Journal of Agricultural Science of the Total Environment, 194, 119-28. Engineering Research, 27, 495-500. Longfield, S.A. and Macklin, M.G. (1999) The Hulme, M., Jenkins, G.J., Lu, X., Turnpenny, influence of recent environmental change on J.R., Mitchell, T.D., Jones, R.G., Lowe, J., flooding and sediment fluxes in the Yorkshire Murphy, J.M., Hassell, D., Boorman, P., Ouse Basin. Hydrological Processes, 13, 1051- McDonald, R. and Hill, S. (2002) Climate 66. Change Scenarios for the United Kingdom: The UKCIP02 Scientific Report. Tyndall Centre for Longfield, S.A. (1998) River response to recent Climate Change Research, School of environmental change in the Yorkshire Ouse Environmental Sciences, University of East Basin, Northern England, Thesis submitted in Anglia, Norwich, U.K., 120pp. partial fulfilment of the requirements of the Ph.D. degree, University of Leeds, 298pp. Institute of Hydrology (1999) Flood Estimation Handbook, Institute of Hydrology, Wallingford, Newson, M.D. and Robinson, M. (1983) 5 volumes. Effects of agricultural drainage on upland streamflow: case-studies in mid-Wales. Journal Konikow, L.F. and Bredehoeft, J.D. (1992) of Environmental Management, 17, 333-48. Groundwater models cannot be validated. Advances in Water Resources, 15, 75-83. O’Connell, E., Ewen, J., O’Donnell, G. and Quinn, P. (2007) Is there a link between Lamb, H.H. (1972) British Isles Weather types agricultural land-use management and flooding. and a register of daily sequence of circulation Hydrology and Earth System Science, 11, 96- patterns, 1861-1971. Geophysical Memoir, 116, 107. HMSO, London, 85pp. Oreskes, N. and Belitz, K. (2001) Philosophical Lane, S.N. (2003) More floods, less rain? Issues in Model Assessment. In: Anderson M.G. Changing hydrology in a Yorkshire context. In: and Bates P.D. (Eds.) Model Validation: Atherden, M. Global Warming in a Yorkshire Perspectives in Hydrological Science, Wiley, Context, Place, York. Chichester, 23-41. Lane, S.N. and Richards, K.S. (2001) The Owens, L.B., Edwards, W.M. and Van Keuran, ‘validation’ of hydrodynamic models: some R.W. (1997) Runoff and sediment losses critical perspectives. In: Bates, P.D. & resulting from winter feeding on pastures. Anderson, M.G. Model Validation: Perspectives Journal of Soil and Water Conservation, 52, in Hydrological Science, Wiley, Chichester. 194-7. Lane, S.N., Morris, J., O’Connell, P.E. and Rauzi, F. and Hanson, C.L. (1966) Water intake Quinn, P.F. (2006) Rural land management and runoff as affected by intensity of grazing. response measures. Chapter 17 In: Thorne, Journal of Range Management, 19, 351-6. C.R., Evans, E.P. and Penning-Rowsell, E., Future Flooding, Thomas Telford, London. Rhoades, E.D., Locke, L.F., Taylor, H.M. and McIlvain, E.H. (1964) Water intake on a sandy Langlands, J.P. and Bennett, I.L. (1973) range as affected by 20 years of differential Stocking intensity and pastoral production 1. cattle stocking rate. Journal of Range Changes in soil and vegetation of a sown Management, 17, 185-90. pasture gazed by sheep at different stocking rates. Journal of Agricultural Science, 81, 193- Robinson, M. and Newson, M.D. (1986) 4. Comparison of forest and moorland hydrology in a upland area with peat soils. International Peat Journal, 1, 49-68.

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Robinson, M. (1986) Changes in catchment runoff following drainage and afforestation. Journal of Hydrology, 86, 71-84. Robinson, M. (1990) Impact of improved land drainage on river flows. Institute of Hydrology Report, 13, Institute of Hydrology, Wallingford, Oxfordshire, 226pp. Robson, A.J. (2002) Evidence for trends in U.K. flooding. Philosophical Transactions of the Royal Society, 360, 1327-343. Sansom, A. (1996) Floods and sheep – is there a link? Circulation, 49, 1-4. Sayer, A. (1992) Method in social science: a realist approach, Routledge, London. Wilby, R. L. (2006) When and where might climate change be detectable in UK river flows? Geophysical Research Letters, 33, L19407, doi:10.1029/2006GL027552.

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Ursula Has Three Eyes - Developing Integrated And Innovative Interventions For Urban River Corridors David Lerner and Tom Wild Catchment Science Centre, University of Sheffield, Icoss, [email protected]

Introduction • People are at the heart of the urban area, Perceptions of urban river corridors are living, working, playing and, of course, changing, oscillating between fear of flooding taking the decisions that shape the area for and a desire for 'blue space' to enhance the its future. This theme is the mechanism to quality of city life. The rapid changes in land work closely with all stakeholders, learning use as their brownfields are redeveloped offer from them and influencing future activities. opportunities to make big and small changes. • The River delivers ecological goods and URSULA is the acronym for a new project services, including landscape, water about rivers in urban areas, led by the purification and quality, ecosystem vibrancy, University of Sheffield. The project's flood control and water resources. New researchers hope to encourage people to create observational data are needed to quantify desirable places for living, working and playing these outcomes for past and future in - that is, sustainable, high quality interventions in urban river corridors. communities. The hypothesis behind URSULA • Design offers the possibility of innovation, (Urban River Corridors and Sustainable Living whether through new concepts or better Agendas) is that there are significant social, integration of existing ideas. We have ideas economic and environmental gains to be made of our own, but will work with stakeholders by integrated and innovative interventions in to identify interventions that should be urban river corridors. designed and tested. • Values are the agents of change (generally Overview of the URSULA project money), and the measures of success. The We will test our hypothesis by providing a theme will develop several new tools for portfolio of interventions, tools and supporting presenting interventions and estimating evidence for the redevelopment of urban river values before assessing the ideas developed corridors to create 'places where people want to in the project. live and work, now and in the future' • Project Management is essential to bind the (www.communities.gov.uk). Our aims are to (1) tasks and deliver the Outcomes, and has understand the current values and potential equal status with the research themes. future values of the benefits of urban development, i.e. to gather the evidence, and (2) propose how we can move from current to These themes provide the interdisciplinary future values by innovation in urban design, structure to the project as well as frameworks and (3) identify how stakeholder interactions for project management and research outcomes. (associated with market, governance or research Within the context of a multi- and inter- processes) impact on river redevelopment. We disciplinary project like URSULA, there are will draw on case studies in Sheffield, the UK both disciplinary and integrating tasks within and beyond, and test our Outcomes with local and across the themes. The tasks offer stakeholders in Sheffield on the corridor of the opportunities for disciplinary research and Don and its tributaries. Five themes address the innovation alongside their contribution to work key issues, as follows: of the project as a whole. From the twin bases

92 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 of overall project needs and research label both approaches as interventions. opportunities, we have identified the 16 tasks Interventions can be of many sorts and at many which are summarised in Table 1. scales, for example creation of a residents' group, a change to transport infrastructure, a URSULA is an interdisciplinary research new strategic plan for the area, a river collaboration between seven Departments in the restoration scheme, a riverside walk, moveable Universities of Sheffield, Bradford and flood defences for a single building, installation Durham, and a wide range of external partners. of micro-hydropower generation, It is funded by EPSRC to the value of £2.5M redevelopment of industrial brownfield sites as over 4 years, providing 310 person-months of residential or parkland, disconnection of storm researcher effort. sewers, etc. We propose to work with local The three "eyes" stakeholders to identify a set of interventions to study. We will build a set of tools to evaluate Interventions the present and future values of their benefits, Change can come about in urban river corridors and develop a decision-making approach which through redevelopment of brownfield sites or can maximise those benefits. by deliberate actions to alter their structure; we

Task Summary of aims To identify and engage stakeholders, to facilitate engagement with them, to analyse the socio-economic impacts of past developments, and reflect on the 1. Community and stakeholders interactions within the whole team. To investigate using the river as a microclimate modifier, a source of cooling for buildings, and a source of renewable energy within the social, economic 2. Using the river and environmental constraints. To build a toolkit for designing storm water options for new-build, redevelopment and retrofit in order to maximise social, economic and 3. Integrated urban water management environmental gains. To develop and test alternative urban forms for river corridors to deliver through 4. Urban form designs creation of a high quality urban environment. To measure how ecological quality and services vary across the Don and tributaries and predict how these are likely to respond to interventions. 5. Generation of ecological data Includes a large fieldwork element. To develop a fuzzy model to predict ecological habitat structures from flow 6. River model characteristics and topography within urban rivers. To provide values of the indicators of ecological goods and services for the 7. Macro-ecological model interventions and scenarios to be tested, using novel graphical modelling. To select the criteria and indicators of intrinsic and extrinsic values that will 8. Indicators support a sustainability assessment of the interventions. To provide an economic and financial analysis of the relations between 9. Financial-physical analysis physical development and design, ecological and environmental quality. To develop a web-base preference/pricing tool with which to analyse the 10. Preference/ pricing tool impact of design, ecological and environmental quality upon property values. To provide a platform for generating and communicating interventions and 11. Visualisation tool testing this as part of the design process for urban river corridors. To test the URSULA hypothesis, and, with stakeholders and researchers, to 12. Assessment of interventions develop integrated and innovative options for Sheffield and beyond. To develop common language, shared goals and good team spirit within the 13. Mobilisation consortium, and prepare a detailed roadmap of activities.

14. Data collection & handling To create and maintain a shared database for the project. To encourage the flow of information and ideas within URSULA; to provide a 15. Project management strong, flexible and responsive management to achieve our deliverables.

16. Dissemination To disseminate the results locally, nationally and internationally.

Table 1. Summary of tasks in URSULA

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Integrated drivers - economic, social and environmental - An essential feature of URSULA is to see that and establishing what lies behind success and any intervention has effects in many domains, failure in different settings, we have the often outside of the intended area. For example, opportunity to bring about real change. We can a riverside residential development affects do this by improving the links between amenity, property values and perhaps social research, policy and practice. cohesion, but it also can affect ecological habitats, transport and flood defences. Good URSULA investigates innovations in two design of the intervention will be able to distinct ways. The first concerns the improved maximise the benefits across all domains. By design and construction of physical working with a multidisciplinary team and with interventions, such as sustainable drainage a wide range of stakeholders, we will be systems, energy production technologies and seeking designs that achieve maximum benefits more efficient approaches to cooling buildings. and ways to make all these benefits clear in the This work clearly relates to the classical decision making process. definition of innovation. The second approach involves facilitating the application of existing Innovative best practices into novel situations, and Innovation is classically defined as the combining them in new ways. Thus introduction of something new. It can also be interventions can be 'hard' or 'soft', with the described as the process of bringing new second type involving institutional change, products, processes and services to the market. policy development and knowledge transfer. In This definition incorporates not only the this respect, a key challenge in URSULA is process of generating new knowledge but also how to bring about the 'innovative integration active work to ensure its uptake and application of interventions'. To be successful, this aspect (see Figure 1). of the project requires inter-disciplinary research, and advanced approaches to A key question facing the URSULA team at stakeholder engagement. the start of the project is whether the approaches being researched are truly Measures of success innovative. For instance, is it really new to The success of URSULA will be judged at a propose that water in the urban environment range of scales, and by multiple audiences. At a should be drained slowly, using infiltration and global and national scale, we need to produce vegetation to both stimulate transpiration and publications which are downloaded, read and remove pollutants? Of course not, these cited by other researchers, while at the same approaches (best management practices or time making an impact on those who make BMPs), were developed and tested in the US as policy and urban river corridors. Will the tools long as 30 years ago. However, we do have the we build and the guidance documents we possibility of achieving something significant prepare be recommended and adopted by and new, if we can better understand the others? Will practitioners want to visit the team, processes that facilitate or block the uptake of attend our events, and look at our website? At a better approaches. By generating new regional and local scale, will our results affect knowledge on the tensions between different

New ideas Practical application

Figure 1. Innovation involves feedback between knowledge and application

94 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 the development of Sheffield and the River Don Acknowledgements corridor, promote even better partnership URSULA is funded by the Engineering and working stakeholders, and influence strategies Physical Sciences Research Council (EPSRC) such as the Regional Economic Strategy, the under the Sustainable Urban Environments Regional Spatial Strategy, the River Basin programme, and supported by the Environment Management Plans, and the Catchment Flood Agency, Sheffield City Council, and a wide Risk Strategy? And not least of all for the range of other partners - see www.ursula.ac.uk researchers involved in the project, its success for details. We are very grateful for their will be measured by the quality of their next support. jobs! Measures of success are given in Figure 2. The diagram shows potential impacts across different scales using the 'spheres of influence' model.

Figure 2. Potential measures of success for URSULA (spheres of influence)

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Community Engagement In Large Scale Landscape Change Associated With New Approaches To Flood Risk Management Steve Maslen Maslen Environmental

Introduction The Estuarine Experience New approaches to flood risk management in The following are a few thoughts drawn from the UK and across Europe are requiring my experience in the estuary environment in significant changes in “our landscape”. These both flood risk related work and regeneration. changes, often physical and reflected in changes in land use, provoke emotional Firstly a few criticisms of myself. To start responses. Local and even national cultural with the word I used in the title “engagement”. traditions to land and water management are This is a very “professional” term for being rolled back to “make space for” or “room something as basic and a lot more human as for” increased water in the landscape. “involving” individuals and groups of people. I have a problem with “engaging” people. It feels The move from traditional “defensive to me as if it’s something “done to” people or positions” is creating opportunities for new organisations and if I was an individual landscapes to appear and the move from potentially affected I would probably think this “defence” to “risk management” creates the is being “done” to me. So let’s be plainer and possibility of our landscape now being less “professionalized” in the words we use to associated with emotional stress. approach people. The changes will affect people both physically and emotionally. The landscape is our habitat and all the Sensitivity reveals itself through behaviour and available evidence is that we care deeply about language so we need to think about both in many parts of it. We care about it for ourselves planning new approaches to our landscapes. and others, our green spaces, our fields, our favourite footpaths. We care for its cultural Living with new risk is dealt with elsewhere references, landmarks and literary landscapes by others in the conference, so I am here and we care about it as a habitat for wildlife. concentrating on the physical changes to the landscape associated with new approaches to These new landscapes, which may be flood risk management and specifically the physically different, such as through managed changes which will be associated with the new realignments in the UK estuaries, and de- and emerging strategies. poldering in Holland, or just where risk of flooding is being introduced to existing Often these new strategies cover large landscapes, present many challenges for the geographic areas, for example the Humber, the affected communities. We do not have all the Sigma Plan on the Skeldt in Belgium or the answers to meet these and our challenge is to Room for the Rivers Strategy for the area pool best practices. I believe there are lessons flanking the branches of the Rhine across the to be learned beyond the flood risk Netherlands. The revealing of these strategies environment, in for example regeneration work however is at a much smaller scale. It is at the where communities are faced with, require and scale of the individual. It’s plots of land with want changes, we need to learn lessons from significance at a community scale. This scale these experiences. step-down from strategy to community change can be huge and as such the navigation of these

96 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 steps down is the major challenge facing involve interested individuals and groups from emerging strategies. From a good strategy best, the local community in the planning and most appropriate and highest quality local management of the proposals. Work with the solutions must emerge. “Local solutions” or farming community at Alkborough started early “community solutions” sounds like in the planning of the project, involving the “regeneration”. I believe there are best practice NFU, researching new options and visits being lessons from work in this area and in particular arranged for the farmers to visit farmers in place based regeneration where people’s lives similar situations elsewhere in the country. are the focus for new activity. Regeneration Interestingly it is the same farm owner evidence points to local people being the key to managers who farmed the land intensively for the solution and success. Solutions are not just cereals who have diversified into sheep and a technical resolution, they are people based. cattle to manage the new landscape through From successful regeneration work we learn licence arrangements. that at the outset you don’t know what the end solution will be, since the community solution The Alkborough project developed into a involves choices – their choices. It involves national flagship demonstration project, which vision and local purpose. extended across Europe. However, the Alkborough approach sought to ensure that the The Alkborough Case Study community interests received as much importance. It has been the small details and There are a number of case studies from the the local relationships which have made this Humber region, which illustrate some of the project such a success. points made. One of these is at Alkborough. A partnership led by the Environment Speaker’s Notes Agency produced a long-term vision for the Steve Maslen worked with his team at Maslen Humber Estuary, the Humber Estuary Shoreline Environmental on the Alkborough project from Management Plan in 2000. This was a the early planning stages, supporting the proactive, rather than a reactive approach to partnership approach and facilitating flood risk management, which sought to community and individual involvement in the develop a coherent and realistic plan for the project. He has worked similarly on the Steart estuary’s flood defences, which would be Pensinsula, Bridgwater Bay and has been compatible with natural estuarine processes, involved in similar projects in Europe. adjacent developments and was sustainable in the long-term. A key element in the proposed Maslen Environmental’s work for the South approach was the establishment of a series of Humber Bank Partnership was rewarded with realignment sites where flood defences could the British Urban Regeneration Association’s be moved creating space for the estuary and National Award for Best Practice in lowering water levels and also creating new Regeneration in 2007. Maslen Environmental is inter-tidal habitats – new landscapes. currently developing a project with European partners which considers how best practices The largest realignment site in the UK and across Europe can be developed to ensure the second largest in Europe was planned and is community solutions arise from strategic now constructed at Alkborough Flats. This approaches in the estuarine environment. extends to 400ha, which was substantially formerly used for arable production. It is now a mosaic of new land uses, habitats and farming. From the outset in the planning of the project it was considered that community ownership and involvement would secure the long-term site management, making it more sustainable. The approach undertaken from the outset was to

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1. View from Alkborough Flats to Alkborough village showing daily inundation channel.

2. View over Alkborough Flats showing new wetlands.

3. Aerial view of Alkborough Flats before works.

98 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008

Strategy and Policy Context of Flood Risk David Murphy

The summer floods of 2007 have highlighted at the causes of the floods and investigating the once again the impact of flooding on people’s emergency response during the floods in June lives, their homes and livelihoods, and on and July. It has sought views from those business and the environment. Flooding is an involved in the floods, including affected issue for everyone right across England and residents, the emergency services, business and Wales, and we recognise the need to work professional associations. An interim report has across government and with our partners – already been published setting out a number of local authorities, internal drainage boards, actions for the industry. water companies, emergency services – to manage the probability and consequences of all Secondly, the Public Accounts Committee forms of flooding. has published its report entitled ‘The Environment Agency: Building and maintaining The policy context of flooding is set out in river and coastal flood defences in England’. Defra’s Strategy for Flood and Erosion Risk This report, based on the National Audit Office Management called Making Space for Water, report and the Public Accounts Committee and their Water Strategy (expected to be (PAC) session of 27 June 2007, identifies a published in February 2008). number of areas where we need to improve. A new European Directive on the The third inquiry is that of Parliament’s Assessment and Management of Flood Risks Environment Food and Rural Affairs (EFRA) came into force on 26 November 2007. The UK Committee into the summer 2007 flooding. It is has two years to bring into force the laws, currently gathering evidence from members of regulations and administrative provisions the public who were affected as well as from necessary to comply with this Directive. The key organisations involved. Directive will require Member States to produce a preliminary flood risk assessment for Our challenge is to continue to learn from all river basins by 2011 and identify areas at the experiences of flood events, and take action significant flood risk. For these areas, Member to adapt to a changing climate and prepare for States will be required to produce flood hazard future flooding. We will continue to improve and flood risk maps (by 2013) and produce our service to everyone that could be affected flood risk management plans (by 2015). The by floods – to help them understand the risks Floods Directive will sit alongside the Water and to take action before, during and after a Framework Directive and it will use the same flood. We will take action, working with others, River Basin Districts for reporting to the to positively contribute to managing flood risks Commission. in a more sustainable way using a wide range of flood risk management activities. There is also a political spotlight on flooding through several ongoing inquiries and reviews. Firstly, Sir Michael Pitt is leading an Independent Government Review of the summer floods. This is being carried out by the Cabinet Office with support from the Department for Environment Food and Rural Affairs and the Department for Communities and Local Government. The Review is looking

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Trees and Water - A Forestry Perspective T.R. Nisbet1, H. Thomas2 & S. Broadmeadow1 1 Forest Research, Environmental & Human Sciences Division, Alice Holt Lodge, Farnham, Surrey, GU10 4LH, UK. e-mail: [email protected] 2 Forest Research, Environmental & Human Sciences Division, Talybont Research Office, Cefn Gethiniog, Talybont on Usk, Brecon, Powys, LD3 7YN, UK.

The Government’s Flood and Coastal Erosion hydraulic modelling studies in south west Risk Management Strategy ‘Making Space for England predicted that the additional roughness Water’, promotes a whole-catchment approach created by a complete cover of woodland along to flood alleviation, drawing on opportunities a 2.2km reach of the River Cary in Somerset provided by rural land use planning and land would reduce water velocity by 50% or more management practices (Defra, 2005). A review and raise the flood level by up to 270mm for a of the literature shows that best management 1 in 100 year flood event (Thomas & Nisbet, practice can help to delay the generation of 2006). This increased the volume of temporary flood flows at the field and hillslope scale but flood storage by 71% and delayed the evidence is weak regarding a significant effect downstream progression of the flood peak by on major floods at the large catchment scale 140 minutes. Floodplain woodland could (O’Connell, 2004; Environment Agency, 2007). therefore help to desynchronise and thereby Land use in the floodplain may be able to exert reduce downstream flood peaks in major river a greater influence on extreme floods by basins, as well as provide more time for issuing providing additional flood storage in the form flood warnings. The main concern surrounds an of washlands and wetlands (Defra, 2006). enhanced risk of upstream flooding above the floodplain woodland due to the backing-up of Forests and woodland have long been flood waters. In the case of the River Cary associated with an ability to slow down run-off example, the flood level was raised by up to and reduce downstream flooding (McCulloch & 180mm over a distance of nearly 400m Robinson, 1993). Deforestation is often cited as upstream. Another issue is an increased risk of a significant contributing factor in the apparent downstream flooding due to the wash-out of rise in flood events in the developing world large woody debris blocking bridges and other (Bradshaw et al., 2007). Forests provide a critical structures in towns and cities. number of options for flood alleviation, principal amongst which is the ability of Funding was received from Defra’s Flood floodplain woodland to slow down flood flows and Coastal Erosion Risk Management and enhance flood storage (Nisbet & Thomas, Innovation Fund in January 2007 to evaluate 2006). This relies on the hydraulic roughness the role of restoring floodplain woodland for created by woody debris dams within stream flood alleviation. The River Laver catchment in channels and by the physical presence of trees, North Yorkshire was selected as the location for shrubs and deadwood on the floodplain. The a study to demonstrate how floodplain net effect of these features is to reduce flood woodland could be designed and managed to velocities, enhance out of bank flows, and reduce downstream flood risk. This catchment increase water storage on the floodplain, was the subject of a multi-agency pilot project resulting in an overall smaller downstream to promote land use options for flood flood event. management and a number of potential sites for woodland planting had already been identified. Recent research confirms that the greater Modelling showed that the restoration of hydraulic roughness provided by floodplain floodplain woodland could delay a 1 in 100 woodland could make a significant contribution year event by 30 minutes or more, with the to downstream flood alleviation. For example, potential to desynchronise the flood peak from

100 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 the adjacent River Skell and so reduce flood conservation, archaeology and cultural heritage. risk at Ripon. Work is underway to persuade Appropriate buffer areas (typically 100m) will land owners to plant woodland on the study be delineated around individual features such as sites and to assess the best woodland design for buildings and minor roads. Main roads and maximising hydraulic roughness. Additional railways are expected to be raised above the instrumentation will be installed to measure the floodplain on embankments and thus these initial impact of the planting on flood flows. features should not require a buffer. Other Monitoring will be maintained to evaluate the factors specific to floodplain woodland will be longer-term effects as the woodland becomes addressed, including the risk of large woody fully established and matures. debris blocking downstream bridges and culverts. Use will be made of the Environment The potential for using floodplain woodland Agency’s draft Catchment Flood Management to reduce downstream flood risk is attracting Plans, especially spatial assessments of flood increasing attention at regional and country risk to people, property, agriculture and levels. Both the England and Scottish Forestry sensitive environmental sites. Finally, Strategies have identified potential opportunities to extend established woodland opportunities for floodplain woodland to and create habitat networks along the contribute to sustainable flood management floodplain will be identified. (Forestry Commission Scotland, 2006; Defra, 2007). At a regional level, creating new The efficacy of new woodland to retain floodplain woodland is listed as one of seven water and mitigate flooding will depend on its priorities for action in the Forestry absolute size and scale in relation to the Commission’s Regional Forestry Strategy for floodplain. Woodland spanning the entire the Yorkshire and The Humber Region (Carter, floodplain will present a more effective barrier 2007). The guiding principles are to prioritise to flood flows than that confined to a single new woodland planting across the region in bank or the margins of the floodplain. Although areas where maximum public benefit can be several small blocks of woodland in close achieved. Flood reduction is an obvious key proximity may be as effective as a single large benefit but others include improvements to wood, the complexity of land tenure makes it water quality, fisheries, carbon sequestration, unlikely that adjacent landowners would sign nature conservation, recreation and landscape. up to a large restoration scheme involving composite sites. Thus opportunities for creating Work is underway to guide the Forestry an effective floodplain woodland are likely to Commission Yorkshire & Humber Conservancy be greatest in the middle and upper reaches of in identifying sites that would be suitable for river catchments. floodplain woodland creation. This is drawing on an earlier methodology developed in the Overall, there appears to be significant scope River Parrett catchment in Somerset that for using woodland to help reduce flood risk. It produced an opportunity map showing is hoped that the field studies at Ripon and preferred areas where the creation or expansion elsewhere will strengthen the evidence base and of floodplain woodland could be expected to support for floodplain woodland as a reduce flood risk (Nisbet & Broadmeadow, sustainable method for downstream flood 2003). The starting point is to define the limit alleviation. The restoration of floodplain of the fluvial floodplain based on the woodland would provide significant socio- Environment Agency’s Indicative Floodplain economic benefits by helping to tackle the Maps for 2000. These illustrate the 1:100 year increasing threat of flooding faced by many flood risk envelope for rivers in the absence of local communities due to climate change, flood defences and the 1:200 year envelope for especially where it is not cost effective to coastal inundation across England and Wales. construct engineered defences. There is also an Constraints to new planting will then be opportunity to develop win-win solutions due considered, including sites scheduled for nature to the ability of floodplain woodland to benefit

101 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 water quality and freshwater habitats, which McCulloch, J.S.G. & Robinson, M. (1993) would contribute to meeting ecological and History of forest hydrology. Journal of chemical quality targets under the EU Water Hydrology, 150, 189-216. Framework Directive. Finally, the restoration of floodplain woodland will help to meet the UK Nisbet, T. R. & Broadmeadow, S. B. (2003) Biodiversity Action Plan Target of creating Opportunity mapping for trees and floods. 2,200ha of wet woodland in England by 2010. Unpublished project report to the Parrett The results, models and suitability maps will be Catchment Project Group. Forest Research, used to support better integration of woodland Farnham, Surrey. and agriculture for flood alleviation elsewhere Nisbet, T.R. & Thomas, H. (2006) The role of in the UK, as well as in the identification and woodland in flood control – a landscape prioritisation of sites for future action. perspective. In: Water and the landscape: the landscape ecology of freshwater ecosystems. References Proceedings of the 14th Annual IALE(UK) Bradshaw, C.J.A., Sodhi, N.S., Peh, K.S.-H. & Conference, Eds B. Davies & S. Thompson, Brook, B.W. (2007) Global evidence that p118-125. IALE(UK), Oxford. deforestation amplifies flood risk and severity in the developing world. Global Change O’Connell, P.E; Beven, K.J; Carney, J.N; Biology, 13, 1-17. Clements, R.O; Ewen, J; Fowler, H; Harris, G.L; Hollis, J; Morris, J; O’Donnell, G.M; Carter, V. (2007) Forestry & flooding. Forestry Packman, J.C; Parkin, A; Quinn, P.F; Rose, Commission (Yorkshire & The Humber) S.C; Shepherd, M & Tellier, S. (2004) Project Briefing Note. Forestry Commission, York. FD2114: Review of impacts of rural land use and management on flood generation. Defra Department for Environment, Food and Rural R&D Technical Report FD2114. Defra, Affairs (2007) A Strategy for England’s Trees, London. Woods and Forests. Defra Publications, London. Thomas, H. & Nisbet, T.R. (2007) An assessment of the impact of floodplain Department for Environment, Food and Rural woodland. Water and Environment Journal, Affairs (2006) Wetlands, Land Use Change and 21(2), 114-126. Flood Management. A joint statement prepared by English Nature, the Environment Agency, the Department for Environment, Food and Rural Affairs and the Forestry Commission: http://www.defra.gov.uk/environ/fcd/policy/wetl ands/Wetlands3.pdf Department for Environment, Food and Rural Affairs (2005) Making space for water: Taking forward a new Government strategy for flood management. Defra Publications, London. Environment Agency (2007) R&D update review of the impact of land use and management on flooding. Environment Agency, Bristol. Forestry Commission Scotland (2006) The Scottish Forestry Strategy. Forestry Commission Scotland, Edinburgh.

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Floods and Land Management Fola Ogunyoye Royal Haskoning

Introduction For rural land management, there is Conveyance of water through land to the seas is substantial evidence that activities such as an important part of the natural hydrological pasture or arable farming including the cycle. Over time, the use of land for various associated drainage and cultivation techniques, economic, social and environmental activities and forestry management, affect the infiltration, has led to the need to manage the risk of run-off and soil degradation/erosion at the flooding, to enable these activities to continue. local/farm scale. For example, management Examples of these include development for practices such as overgrazing, compaction by housing, commercial and industrial purposes, heavy machinery, cultivation/drilling during agriculture and associated infrastructure. These inappropriate weather or soil conditions all activities are generally not compatible with increase the generation of run-off and soil flooding. In fact, they often affect the water erosion. Similarly, increased soil erosion leads balance and prevent or alter the form or speed to siltation of watercourses and of conveyance of water through them. The restriction/blockage at critical structures such as challenge of the wider industry is to understand culverts. The significance of these effects relies the effects of these changes on the risk of on the relative scales and capacities of the flooding, and develop measures to enable receiving watercourses and structures. The appropriate land management practices that are extent of propagation of these local effects to a compatible with sustainable flood risk national scale is presently inconclusive. The management. inability to justify clear catchment scale effects may be largely due to the inability to properly How Does Land Management Impact model the complex relationships involved. on Flood Risk? Despite the lack of conclusive scientific Land management influences the probability of evidence at the catchment scale, there is already flooding. It does this by changing the a body of anecdotal evidence that land generation and propagation of flooding, and the management is having effect on flooding of consequence of flooding by changing the downstream areas. The investigation of the impact on land vulnerability and susceptibility flooding in Crowlas, Cornwall, UK is an to floods. example of this (Hall, 2005). Here, it seemed apparent that the farm management practices to The effect of urban development such as support intensive cultivation had led to buildings and associated infrastructure such as significant soil degradation/erosion and pavements and roads on flooding is well increase in run-off, which seemed to be known. It is already very clear that such contributing significantly to the flood risk of development can increase run-off significantly downstream Crowlas. It is noted that in this when compared to natural green field case, a significant part of the catchment equivalents. It is also clear that the effect of upstream of Crowlas is arable and has in recent these at the catchment scale can be significant. times become more intensively farmed. As a result a number of measures such as sustainable drainage systems (SUDS) are being Recent major UK research to assess land used to minimise this impact. management and flood risk impact include the Ripon, Parret and Pontbren Catchment pilots. Recent studies include two Defra projects HA6 and HA7, to support the “Delivery of Making

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Space for water” (Defra, 2008), R&D update At the national level, the policy for review of the impact of land use and managing flood risk in England within management on flooding (Environment Agency, “Making Space for Water” requires an 2007), Review of Impacts of rural land use and integrated approach to flood risk management management on flood generation (Defra, 2004a using a portfolio of measures to manage the and b) and the integration of agricultural, sources, pathways and receptors of flood risk. forestry and biodiversity conservation policies A key aspect identified within this is Land and flood management project (LUPG, 2004). Management. Over the past two years, Defra The above current state of knowledge shows has commissioned focussed studies to assess that there is a clear need for continued research the management of land with respect to flood into this area. In the meantime a precautionary risk management. These studies are now approach would be sensible. As compared with starting to deliver outputs which will be used to major urban development, the rural land shape future policies. Current instruments such management effects is the area with most as Catchment Flood Management Plans and the unknowns, as a result this paper has focused development of flood risk strategies already more on this area. offer the opportunities to consider land management as part of the strategic solutions Current Policy and Management for flood risk management. Approaches In addition to direct policies and initiatives Over the past decade, a number of policies and within flood risk management, other relevant management mechanisms at the European and national policies and schemes relate to national scales have led the move towards agricultural and forestry management. This sustainable land management approaches. includes the Common Agricultural Policy and While most of these are not primarily aimed at associated payment schemes, Environmental flood risk management, they do generally result Stewardship schemes and Woodland Grant in delivering multiple benefits including flood schemes. The objectives of these schemes are risk reduction. generally to encourage environmentally At the European level, the relevant friendly land management and farming methods instruments include the Water Framework through financial support and incentives. While Directive (WFD), Soils Framework Directive the primary objectives of these schemes are not (SFD) and the Floods Directive (FD). WFD is flood risk management, they often deliver targeting rural land management activities that multiple benefits, of which flood risk is directly result in unwanted diffuse pollution, sediment and indirectly a beneficiary. The resulting and hydrological regimes as part of measures to measures often result in reduction of soil achieve good ecological status or potential erosion and surface water run-off, with clear within water bodies. Similarly, the SFD targets flood risk management benefits. The sheer size the preservation of soil through prevention of of land covered by these schemes make their soil degradation and restoration of degraded potential quite significant. soils. Both WFD and SFD have the capacity to indirectly reduce flood risk through land Recommendations management practices that reduce flood peaks The following actions are recommended to and sediment sources. The FD seeks a more improve the management of land for flood risk strategic approach to flood risk management benefits: through provision of information on, and Further research required on catchment/sub- strategic planning of flood risk. This can be catchment scale flood risk impacts used as an added driver to consider whole It is clear that effective land management catchment approaches including the role of land practices that preserve soil structure and reduce management within this. soil erosion, run-off peaks and volume have significant benefits for flood risk. While this

104 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 has not been scientifically proven at a Integrates system-based solutions (similar to catchment scale, its effects are clearly being SUDS) seen at the local scale. The current science Sustainable solutions for land management for based needs to be improved with R&D to flood risk benefits will need to develop from understand the complex relationships between individual solution to integrated system based land management practices and the generation solutions. This will need to be similar to the and propagation of flood risk, in particular at concept of management train adopted in SUDS the catchment wide scale. The research will to enable a series of treatment commencing as need to examine a wide range of scenarios. close as possible to the source and continuing onto a wider site and sub-catchment scale. It Precautionary approach will need to involve a range of measures The inability to observe significant effects at applicable to particular locations to address the catchment scale is likely to be a woodland management, grazing stocking rates, combination of dilution effects and the inability on-site detention/storage, maintenance of to model the complexity of the relationships. In adequate infiltration through use of appropriate such circumstances, the only pragmatic way plant and methods, provision of forward in the short/medium term is to invest buffers/hedgerows reduction of run-off and soil more in understanding the science while taking erosion. a precautionary approach which focuses on the reduction of soil erosion and run-off and their Address pressures from lower levels within impacts on generation and propagation of supply chain flooding through effective land management It is recognised that at the current trend of practices. This will help to achieve no regrets intensive cultivation is also complicated by solutions. stringent requirements lower down in the supply chain. This has led to harvesting and use Focus on delivering multiple objectives of heavy plant machinery during periods of including flood risk management very wet weather and inappropriate soil It is noted that given the current uncertainties, conditions, leading to soil over-compaction, obtaining significant flood risk management degradation and erosion. The existing funding may be an issue. This should be regulatory and subsidy systems should be used addressed by focussing on delivery of multiple to prevent such occurrences as these could benefits to include flood management, diffuse undermine other good practice management pollution, biodiversity, water demand, being carried out. conservation, amenity, heritage and social well- being. Opportunities for joined up working and Joined-up delivery mechanisms for higher funding will need to be maximised in this level plans and strategies regard. The fact that most of the areas that need The delivery mechanisms of current strategic a joined up approach mostly fall within the documents such as Catchment Flood same organisation, such as Defra in England Management Plans (CFMPs) and Catchment should make this a manageable challenge. Abstraction Management Strategies (CAMS) need to be linked at regional levels to enable Target flood risk benefits within existing achievement continue to encourage improved land management initiatives water management at site and regional scales. A It is recognised that flood risk management is number of the above and similar environmental currently a secondary objective of some of the strategies point to the need for improved regulatory and stewardship schemes. These strategic detention, storage and re-use of water, need to be reviewed and targeted to achieve for water resources, demand management and more benefits for flood risk reduction. flood risk management benefits. There is a need to establish a delivery mechanism at the regional water management level for taking forward initiatives that jointly deliver these

105 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 benefits, with links to local land management Defra and Environment Agency (2004b) needs. Within this, aiming to hold as much Review of the impacts of rural land use and water at appropriate strategic locations and management on flood generation. Current state within the wider drainage systems and flood of managed rural land and mitigation measures. plains to reduce the frequency of water R&D Technical Report. FD2114/TR. abstraction and discharge and associated energy and water demand/discharge. This should help Environment Agency (2007) R&D Update reduce the need for significant irrigation a few review of the impact of land use and days (or hours) after heavy rainfall and management on flooding. discharge to downstream areas. Land Use Policy Group (2004) The Integration Improved links with the planning system of Agricultural, Forestry and Biodiversity All development and management practices Conservation Policies with Flood Management have the potential to affect the natural and built in England & Wales. environment. There is a need for increased use Murphy D. (2007) Ripon Multi-objective of the planning system to regulate land Project: Final Report, Defra. management, to prevent negative impacts, including flood risk. This needs to receive Henshaw, A, and Thorne, C.R. (2007) similar attention as is currently enjoyed by the Catchment restoration for flood risk and urban/built environment. sediment management. Pontbren, Mid-Wales. River Restoration Centre 8th Annual Education of land managers Conference Proceedings. While information and guidance on good land management practices are becoming more Park, J. and Cluckie, I. (2006) Whole available, there is now a need to focus efforts Catchment Modelling Project. Technical Report on reaching the land managers at the sharp end. to the Environment Agency. The Parrett This can be done through programmes carried Catchment. out in conjunction with organisations such as Hall, H. & Davies, J., Royal Haskoning & the Farming and Wildlife Advisory Group and Environment Agency (July 2005) Farming in the National Farmers Union. the Control of Flooding in Small River Basins. References Proceedings of 40th Defra Flood & Coastal Management Conference 2005. Defra (January 2008) Delivery of Making Space for Water, HA6 Catchment Scale Land- Communities and Local Government Use Management, HA7 Land Management (December 2006) Planning Policy Statement Practices, the role of land use and land 25: Development and Flood Risk. management in delivering flood risk management. Defra (March 2005) Making Space for Water, First Government response to the autumn 2004 Making space for water consultation exercise. Defra and Environment Agency (2004a) Review of the impacts of rural land use and management on flood generation. Impact Study report, R&D Technical report FD2114/TR.

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Risk Assessment Approaches For Pluvial Flooding Chris Procter, Lucy Wilson, Steven Anthony & Steve Humphries ADAS, Woodthorne, Wergs Road, Wolverhampton. WV6 8TQ

Introduction and low-cost approach that could be taken to assess an urban site for risk from pluvial The exceptional rainfall events that the UK flooding will be considered and discussed in experienced during the summer of 2007 gave this paper. rise to widespread and long-lasting flooding that caused a considerable amount of damage to Approach homes and businesses, and resulted in serious financial losses. Much of the areas under flood The risk assessment approach discussed here were not considered at risk from more comprises three stages: (i) a GIS-based commonplace fluvial (river) flooding as defined screening exercise to identify sites that are by the Environment Agency (EA) flood risk potentially at risk as indicated by analysis of zones, and were therefore unprepared for such topography using high resolution digital events and did not have effective mitigation elevation models (DEMs); (ii) further targeting measures in place. Whilst there is a wealth of of sites for field visit by applying simple research into methods of predicting and rainfall runoff models to each catchment where modelling fluvial flooding, there are relatively the topography is conducive to flooding using few documented risk assessments or models of land cover and soil type databases and (iii) flooding caused by heavy rainfall (pluvial visits to sites identified as potentially at-risk to flooding). carry out a more detailed survey of site-specific factors that may affect flooding risk such as Pluvial flooding results from high intensity drainage capacity and surrounding land use. or prolonged heavy rainfall leading to overland flow and ponding. Flooding can also occur due In this context, we define a site as being a to exceedence or blockage of sewerage and small area of developed land such as a drainage systems. The risk to a site from residential postcode, a treatment works or a pluvial flooding will be dependent on a number business address that can be considered a point of factors including topography (e.g. sinks or location for the purposes of the risk assessment. depressions where water might collect), the percentage of sealed surface within the 1. Initial screening of sites using DEM data upstream catchment area and the drainage The first stage of the risk assessment process capacity within the catchment area (Waller et could be to identify sites that are situated such al., 2007). that rainfall water could collect and cause localised flooding. This would require the use Industries that provide public services such of high resolution DEMs that accurately as electricity and water were badly affected by reproduce the topography of the catchment. For the summer floods, which in turn had serious each site, the drainage catchment boundary knock on effects. Assigning a risk score for could be determined from the DEM. The pluvial flooding to sites such as water treatment drainage catchment boundary would include all works and electricity substations would help land immediately surrounding the site that is at the early identification of high-risk sites and a higher elevation, and from which any rainfall allow preventive action to be taken prior to a runoff will be directed towards the site. The forecast heavy rainfall event. Such risk susceptibility of the site to accumulated flow assessments would need to consider various could be determined using another function of physical factors and draw on previously ‘Hydrologic Analysis’, which identifies sinks, documented models of rainfall runoff. A simple i.e. cells from which water will not flow out.

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2. Rainfall runoff model (1971-2000) is available from the Met Office, The Wallingford Procedure modified rational and could be used to obtain a rough estimate of method estimates peak run-off rates from SAAR for each catchment. UCWI values can rainfall (Mitchell et al., 2001), and could be then be determined from a function fitted to the used for catchments identified as being curve (Mitchell et al., 2001). potentially at risk of flooding by initial DEM screening. This model uses data that are 3. Site Visits available at a drainage catchment level, Site visits could be carried out at locations including (i) the percentage of the catchment identified as high risk by (i) to improve the area covered by impervious surfaces, (ii) a soil parameter estimation used in the rainfall runoff index based on the HOST classification and model. The data gathered at site visits could (iii) an urban catchment wetness index. include the local topography, land use in surrounding areas, proximity to watercourses, The percentage of the catchment covered by potential for channelling of runoff (e.g. sloping impervious surface could initially be estimated road leading to site), and an estimate of the for each catchment using a combination of high drainage capacity. The adequacy of the resolution landcover data, which provides a drainage capacity to accept flood water value for the percentage of the cell that is associated with heavy rainfall could then be urbanised, and postcode boundary maps that determined using the estimate of peak runoff can be used as an estimate of the number of from (ii). residential dwellings in a catchment. Impermeability values for UK urban The sensitivity of the site to change in either catchments are based on the basic uses (i.e. the characteristics of the catchment or the industrial, residential) and the density of drainage capacity could also be estimated using residential dwellings (Ellis, 1986). data gathered from site visits and altering parameters in the rainfall model. For example, The SOIL index was originally based on if the percentage impermeable surface Winter Rainfall Acceptance Potential (WRAP), increased and the drains were partially blocked, which is a soil hydrological characteristic – the by what factor would the flood risk increase? reverse of runoff potential. It is now generally accepted that HOST, which is the successor to The simple risk assessment approach WRAP, can be used to obtain a standard discussed here could be used to target flood percentage runoff (SPR) for the catchment in defence resources to those sites where the risk place of SOIL. In the absence of high from pluvial flooding is identified as being resolution soil hydrology data, it would be highest, or to improve the drainage capacity at possible to assign a HOST class to soils in the such sites to reduce the risk. European Soil Geographical Database The methods presented are designed to (ESGDB), which is available as a vector provide commercial organisations with a cost dataset. The SPR index could then be derived effective approach to assessing their assets in a from the proportion of each HOST class in the pragmatic way. The techniques chosen are catchment using a simple equation (Boorman et specifically selected to provide the best al., 1995). estimate of risk with relatively minimal The urban catchment wetness index reflects investment. the role of surface storage in runoff estimation and can be determined with reference to the References standardised annual average rainfall (SAAR). Boorman, D.B., Hollis, J.M. & Lilly, A. (1995) Analysis of long term rainfall runoff records Hydrology of Soil Types: a hydrologically show that there is a very good relationship based classification of the soils of the United between UCWI and SAAR (DoE, 1981). Data Kingdom. Report No.126, Institute of on annual average rainfall at 5km resolution Hydrology.

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DoE (1981) Design and Analysis of Urban Storm Drainage: The Wallingford Procedure. Volume 1. Principles, Methods and Practice. National Water Council standing technical committee report, 28, Department of the Environment. Ellis, J.B. (1986) Pollutional Aspects of Urban Runoff. In: Torno, H.C., Marsalek, J. & Desbordes, M. Urban Runoff Pollution. Springer Verlag Berlin. Mitchell, G.., McDonald, A. & Lockyer, J. (2001) Pollution Hazard from Urban Nonpoint Sources: A GIS-model to Support Strategic Environmental Planning in the UK. Technical Report, School of Geography, University of Leeds, 122 pp. (http://www.geog.leeds.ac.uk/projects/nps). Waller, S., Astle, G.., Wagstaff, S., Kitchen, A. & Kellagher, R. (2007) A preliminary investigation into the possibility of flood mapping flooding from other sources. Project HA4a, Defra: making space for water.

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Managing Flood Risk And Delivering New Habitat - Experience From The Environment Agency Regional Habitat Creation Programme Nathan Richardson1, Danielle Phillips1, Paul Miller2, Duncan Huggett2 1 Atkins 2 Environment Agency Contact: Dr Nathan Richardson, Atkins, Broadoak, Southgate Park, Bakewell Road, Peterborough PE2 6YS [email protected]

Abstract Drivers for Habitat Creation In the course of carrying out its flood risk Habitats & Birds Directives management functions, the Environment The EU Birds Directive2 and Habitats Agency needs to create a range of wildlife Directives3 are implemented in the UK through habitats in order to replace those lost as well as the Habitats Regulations4. Habitat creation as a to enhance the natural environment. These consequence of flood risk management requirements arise from both statutory activities may arise because: obligations and from the need to implement Government policy. 1. There is a requirement to ensure the overall coherence of the Natura 2000 network is This paper describes these drivers for habitat maintained should any site be damaged by a creation and how the Environment Agency in permitted plan or project; and its Anglian Region is working with consultants 2. Flood risk management functions must be and a range of conservation organisations to exercised to secure compliance with the meet them through the Regional Habitat Habitats Directive. This has particular Creation Programme. The programme has been implications where sites are subject to long running for 3 years and has developed tools and term change (e.g. coastal squeeze). approaches to assess and track habitat losses and gains; to identify appropriate sites for new habitats to be created; and to secure funding, When a scheme is progressed and there will be permissions and consents to allow habitat an adverse affect on a Natura 2000 site, then creation to happen on the ground. compensatory measures, such as habitat creation, must be taken5. This assumes that A series of workshops have been held with there are no alternative, less damaging representatives from other regions of the alternative options and that an imperative Environment Agency, many of whom are reason of overriding public interest exists6. It is adopting and adapting the approach and lessons Government policy that compensation is learnt in Anglian Region to push forward their secured before the damaging works can be own habitat creation programmes. consented or carried out7. Furthermore, where new habitats are created as compensatory measures, the newly created habitats should be in place in time to provide fully the ecological functions that they are intended to compensate for8. Whilst these requirements apply to plans and projects, the law also requires Government to ensure more general compliance with the

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Habitats and Birds Directives. For example, the strategic and long-term view, a view which is Habitats Directive requires Member States to promoted by Defra that encourages operating take appropriate steps to avoid deterioration of authorities to anticipate habitat creation Natura 2000 sites9 whilst Article 3 of the Birds requirements and opportunities12 and to Directive requires them to take the requisite establish habitat creation programmes13. Where measures to preserve, maintain or re-establish a such programmes are developed they will need sufficient diversity and area of habitat for to have a clear system of recording, reporting specific populations of birds. Where and accounting for habitat created. The system deterioration is unavoidable then it may be will need to be readily auditable and necessary to create replacement habitats to transparent so that the statutory drivers and ensure the overall objectives of the Directives outcomes are clear. are met. This is particularly the case where designated sites with intertidal habitats Defra also promotes the development of (particularly saltmarsh and mudflats) are 'anticipatory' land acquisition in order to subject to long term detrimental changes in facilitate a strategic, planned approach to 14 habitat due to coastal squeeze resulting from habitat creation . This involves buying land for sea level rise. the specific purpose of creating habitats to compensate for the impacts of future Defra Policy, Outcome Measures & development. Whilst the Habitats Regulations Environment Agency Corporate Targets do not lend themselves easily to this approach, It is Government policy that as a minimum, Defra accepts that where a strategic or regional flood risk management works must be assessment has been made of flood risk environmentally acceptable. Furthermore, management needs, a controlled form of 'land bodies such as the Environment Agency are banking' is acceptable. However, it is important encouraged to seek opportunities for that the following criteria are applied: environmental enhancement when selecting flood and coastal defence options at a strategic • Land should only be purchased once predicted losses have been identified, either level and when developing schemes10. This was enshrined in High Level targets agreed between specifically or in principle. Defra and the Environment Agency which have • Where land is being acquired as now been replaced by Outcome Measures. compensatory habitat, it can be used as Outcome Measure SD3 tracks the area of UK compensation following liaison with local Biodiversity Action Plan habitat achieved planning authorities and Defra on an through risk management activities. The appropriate assessment for the scheme to objective is to achieve a net increase in ensure that no reasonable alternatives exist Biodiversity Action Plan habitat achieved and that there is a case of overriding public through flood and coastal erosion management interest. activities. Although no target has been set yet, • Land should normally be acquired within the reference is made to the fact that the existing area of the strategic plan that identifies a target is 200 hectares per year, of which at least need for it. Where habitat creation 100 hectares should be intertidal habitat to opportunities are limited within one Coastal address habitat being lost through coastal Habitat Management Plan (CHaMP) area squeeze. This latter target is reflected in the due to, for example, the area being heavily Environment Agency's own corporate plan as a developed, habitat may be created elsewhere performance target11. by agreement. For example, elsewhere in the same Natural Area or potentially further In order to deliver on statutory obligations afield (e.g. in another Environment Agency and to achieve the Outcome Measures, there is region). a need to be proactive. Opportunities to create habitats need to be sought as early as possible in the planning process. This means taking a

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• Where there is a need to create freshwater • Phase II involves the identification and habitats it may be more sustainable to create investigation of suitable sites on which habitat well inland. However, any decision compensatory and BAP habitat can be to create compensatory habitat remote from created. the affected area must be supported by • Phase III involves gaining control over those Natural England and approved by Defra. sites and the creation and long-term management of appropriate habitat. The Environment Agency Anglian Regional Habitat Creation Programme Overview The Environment Agency Anglian Regional Habitat Creation Programme (RHCP) was initiated in 2004 with the aim of providing a strategic approach to identify and address both statutory and non-statutory habitat creation requirements. Several advantages were identified in developing a regional habitat creation programme: • Site acquisition can be undertaken pro- actively and good opportunities seized as and when they arise. Phase 1: Review habitat losses (see Figure 1) An assessment of habitat losses is undertaken • Habitats should be created before they are including: lost. This should: • Reduce flood risk management project 1. Potential habitat loss from Natura 2000 sites: implementation time and costs; and • Direct losses due to flood risk management • Reduce the habitat creation 'multiplier' (the works; and ratio of habitat that needs to be created to • Indirect losses and long term deterioration that which is being lost - this is normally (e.g. due to coastal squeeze). considerably more than 1:1 because of the uncertainty of successful habitat 2. Losses of BAP habitat due to flood risk replacement). management works • Land can be purchased at a fair price (i.e. the Annually the Anglian RHCP assesses the most market rate) which should lead to substantial up to date Long Term Plan (LTP). This cost savings. provides details of schemes and strategies • Piecemeal creation of habitat is avoided with proposed during the forthcoming 10 year larger, more ecologically robust sites period. A definitive list of the Region's projects, created. schemes and strategies is drawn up and projects The Anglian RHCP has three distinct phases or identified that may affect designated habitat elements: sites, result in BAP habitat losses or provide opportunities for habitat creation over their • Phase I involves the identification of future design life. losses to internationally designated sites and of BAP habitat due to flood defence projects Once the list of schemes, projects and and plans, as well as identifying potential strategies has been identified, further schemes through which significant discussions with Environment Agency Project biodiversity enhancement may be realised. Managers, environmental staff and their consultants are undertaken and key project

112 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 documents are reviewed in order to establish where Natura 2000 sites require compensation. the potential scale, nature and timing of habitat The Anglian RHCP has established a database loss. Discussions are also held with Natural that enables data to be collated, stored, updated England and other conservation organisations to and analysed. The advantage of establishing identify, on a case by case basis, what the likely this is that it is: impacts would be on the site features and consequently the anticipated habitat creation • Transparent - the limitations of the data-set requirements. and the assumptions of the assessment are clear. At any point in time the estimate of future • Updateable - as the estimates of habitat gains habitat losses is a 'best guess' based on the level and losses evolve over time, it is important and accuracy of available information. The that the database is managed and updated estimate is refined and updated each year as (ideally annually). information comes to light and as projects and • Flexible - the information held within the plans develop. The actual need for habitat database is open to be extracted and creation is formally confirmed only once the analysed in a wide range of ways (e.g. by planning process (for habitat compensation, this geographical area, by funding body, by includes the Regulation 48 process) has been protected site, by habitat type etc). completed. Any discrepancies in the area of habitat created, compared to habitat lost are • Traceable - any updates or changes to the dealt with in the maintenance and management database are evident and the reasons stated. of the balance in the longer term. • Transferable - it can easily be adapted and used by other Regions. The habitat loss assessment and the balance Phase 2: Identify sites for habitat creation (see of losses and gains will evolve with time as Figure 2) projects develop and schemes are implemented. Phase 2 of the RHCP focuses on identifying Therefore, it is important that the development suitable land with the appropriate physical and of the agreed list of schemes, projects and ecological characteristics where habitat can be strategies likely to require habitat creation, created. leaves a clear, auditable 'paper trail', especially

Figure 1

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Site analysis criteria appropriate to a range • Infrastructure (buildings, roads, railways, of target habitat types are held within a bespoke pylons) geographical information system (GIS). Criteria • Flight safeguard zones (MoD, CAA) utilised within the GIS include: • Planning boundaries (county, local) and • Distance from the loss location/international existing planning consents (e.g. minerals site (5km, 10km, 20km, 50km) development) • Topography (using LIDAR data where • Water quality (chemical and biological) available or NextMap/OS Profile) • Land ownership and willingness to sell (to • Soil type be added as information is obtained) • Drift geology • Water features (rivers, drains) and water The GIS critically assesses each location and resource availability ranks it against other locations providing a visual presentation of the comparative • Existing abstraction licences and discharge suitability of often large areas of the Region consents (Figure 3). It is used both pro-actively to find • Land use potential areas where we can address known • Designated nature conservation sites (SPA, losses and reactively to quickly screen the SAC, SSSI, CWS) potential suitability of land that is offered to the • Flood risk areas, pumping stations project.

Figure 2

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The GIS outputs are used as the starting payment. This approach can avoid the risk of point for discussions with Natural England and having to pay excessively high fees for 'ransom conservation organisations as to those strips' of land. sites/areas that are considered most appropriate and where efforts will be focused in Further site specific information is then approaching landowners. At this stage, it is obtained to determine any significant important to know what the programme is environmental or design constraints and to likely to be able to offer landowners financially confirm the suitability of the land for the (e.g. market rate + farm re-organisation desired habitat. Information on the permissions payments). The availability of land and consents required for habitat creation is management options and payments should be obtained and initial discussions are held with also established through discussions with consenting bodies (e.g. the local planning Natural England. The landowner's views or authority, Natural England), and other key local preferences between selling land or some form interests, on the likely acceptability of of long-term lease arrangements can then be proposals. established. Where multiple landowners are Phase 3: Securing Sites and Creating Habitat involved then one approach that has been At this point land acquisition and design of the adopted is to secure 'options to purchase' paid habitat is progressed following internal for through an upfront percentage of land value approval of funds within the Environment (say 10%). These options oblige the landowner Agency. For most sites a partner conservation to sell at some point in the future should the organisation is identified and procured who will Environment Agency accumulate sufficient land help design the site, lead the habitat creation area to be able to progress a viable habitat and then manage the site itself in the longer creation project. If the Environment Agency term. A few sites are designed and created walks away the landowner retains the option without a partner conservation organisation but Figure 3

115 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 directly with a landowner. For example a • Supervising and interpreting ground landowner may choose to retain ownership of investigations the land but agree to work in partnership with • Elements of outline and detailed design and the Environment Agency to convert all or part costings of their land for habitat creation. • Drafting planning applications Experience to date has shown that a multi- • Undertaking Environmental Impact disciplinary team which includes various Assessment studies functions of the Environment Agency (National • H&S and CDM Co-ordinator services Capital Project Management Service, National • Undertaking flood risk assessments Environmental Assessment Service, Estates, Legal, Fisheries, Recreation and Biodiversity), • Providing reservoir design and panel the conservation organisation and utilising engineer services consultant support has been needed to see a site • Obtaining impounding licences, abstraction through from its identification as potentially licences suitable in Phase 2 through to habitat being • Developing site monitoring packages created and managed (Figure 4). For example, as consultant, Atkins is progressing work strands such as: As the programme nears its third anniversary we have six habitat creation projects in • Preparing business cases to secure funding progress which will deliver reedbed, floodplain approval grazing marsh and intertidal habitats (Table 1). • Assisting in procuring a conservation The projects are being progressed with the organisation to create and manage the site involvement of both conservation organisations • Undertaking specialist surveys such as water as well as landowners. quality, flow, soils, protected species

Figure 4

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Site Name Habitat Type Conservation Area to be created Anticipated Timescale Partner Marsh Farm, Floodplain RSPB 94 ha Operational Frampton (see grazing marsh photos below) Welney Floodplain Wildfowl and 38 ha Construction 2008/09l grazing marsh Wetlands Trust Abbey Farm, Reedbed and RSPB 21 ha each (total 42 Construction 2008/09 Snape floodplain ha) grazing marsh Hilgay ReedbedNorfolk Wildlife 40 ha Construction 2008/09 Trust Grazing Marsh 25 ha

Hamford Water Intertidal and Landowner 50 ha Construction 2008/09 saline lagoon Wallasea Island Intertidal RSPB 620 ha (EA Construction 2010 mudflats and contribution equivalent saltmarsh, to approx 200 ha saline lagoon, intertidal) brackish grazing marsh Table 1 The Environment Agency, Atkins and others conservation organisations such as the RSPB, are also progressing a major project to create Wildlife Trusts, Wildfowl and Wetlands Trust up to 1000 ha of new wet grassland habitat near and National Trust so that they are comfortable the Ouse Washes to address past deterioration alongside the Environment Agency, sharing of the site. While all these projects and sites are plans and working together to acquire sites and being developed, other opportunities are deliver habitat. There is also scope to assist continually being explored through the Anglian other operating authorities deliver habitat Regional Habitat Creation Programme to creation requirements (e.g. Local Authorities address future needs. and Internal Drainage Boards). Conclusions The Anglian Regional Habitat Creation Programme shows that it can be done. From The key to getting habitat created and to identifying habitat needs, to finding suitable meeting both statutory and non-statutory sites and now to habitats being created on the requirements, is finding the opportunities. ground. It is playing its part in ensuring that Having set up a Regional Habitat Creation habitat creation needs arising from statutory Programme in Anglian Region, finding obligations and Government policy are met. opportunities has proved to be the greatest challenge facing the team. Meeting habitat The programme provides a set of tools and creation needs means the Environment Agency an approach that is transferable and is being is having to get better at identifying and taken up in other Regions of the Environment capitalising on opportunities that arise as part Agency. All Regions are now developing of the 'day job'. Natural England has to help similar programmes. However, a national identify not only how flood risk management framework is needed which ties these together. schemes might damage designated sites, but This would promote co-ordination of habitat also where significant and appropriate habitat creation at the highest level and could facilitate enhancement opportunities exist. Long term habitat trade-offs between Regions. Finally, a partnerships need to be developed with

117 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 national land acquisition strategy is needed to References complement those developed for the Humber, 1 The views expressed in this paper are those of Ouse Washes and on the Anglian programme. the authors and do not necessarily those of the Acknowledgements organisations they represent. Many people have contributed to the 2 Council Directive 79/409/EEC on the development of the Anglian Regional Habitat conservation of wild birds Creation Programme. However, the authors 3 Council Directive 92/43/EEC on the particularly wish to acknowledge the conservation of natural habitats and of wild contribution made by Peter Doktor flora and fauna (Environment Agency NEAS), David Collins (Environment Agency Coastal Strategy 4 Regulations Conservation (Natural Habitats & Manager). C.) Regulations 1994

5 Regulation 53 of the 'Habitats' Regulations 1994

6 Regulation 48 & 49 of the 'Habitats' Regulations 1994

7 Section 5, Coastal Squeeze - Implications for Flood Management: The Requirements of the European Birds and Habitats Directives. Defra Policy Guidance, September 2005)

8 Paragraph 30, Government Circular: Frampton - prior to works Biodiversity and geological conservation - statutory obligations and their impact within the planning system (Defra Circular 01/2005)

9 Article 6(2) of the Habitats Directive

10 Paragraph 3.9, High Level Targets for flood and coastal erosion risk management. Defra, 14/03/05

11 Environment Agency Corporate Plan

12 Section 5, Coastal Squeeze - Implications for Frampton - 2 years later Flood Management: The Requirements of the European Birds and Habitats Directives. Defra Policy Guidance, September 2005

13 Ibid

14 Section 3.5.3, Managed Realignment: Land Purchase, Compensation and Payment for Alternative Beneficial Land Use (Defra 21/03/03)

Ditch creation at Frampton using the RSPB rotary ditcher

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A Gloucestershire Perspective on the 2007 Summer Flooding Carolyn Roberts University of Gloucestershire

Context public and preparatory information, the Planning policy and sustainable drainage discussions amongst stakeholders, the views of systems (SuDS) are potentially important individuals and the final Report. weapons in the armouries of government and communities for reducing the impact of What happened, why and when? flooding on the UK landscape. Approaches to The floods of summer 2007 and their aftermath the complex problem posed by extreme in Gloucestershire and the surrounding counties flooding have shifted over the years from were allegedly the largest civil emergency in controlling the water, to impact minimisation the UK since World War II. Thousands of and adaptive management. This is the result of properties were flooded, both on the broad various types of drivers for change (Johnson, floodplains of the Rivers Severn and Avon, and Tunstall and Penning-Rowsell, 2007). The from smaller streams, ditches and impermeable context of flooding has always been a key surfaces in villages and towns across the determinant in steering these new policy region. Major areas of towns such as responses. The physical characteristics of Gloucester, Cheltenham and Worcester were notable floods, and the technology, information devastated. Some properties were swamped two and understandings of the time have been or three times, initially in June 2007 significant. The values, beliefs and attitudes of (concurrently with large scale flooding in key stakeholders, and the socio-economic and Humberside and Yorkshire), and later on a political contexts are also crucial, especially further one or two occasions in July. The given the attention now being paid to social inundation, contamination and failure of core learning as a legitimate part of public services such as water and power supplies participation in water management (Collins and affected over 400,000 of the county’s people Ison, 2006; Pahl-Wostl, 2006). directly, and many more indirectly as a result of disruption; the revelations of single points of This paper describes the background and failure such as Walham electricity sub-station unexpected implications of the major flooding potentially compromised 500,000 residents events of Midland England in summer 2007, within and beyond the county. Fortunately, the and explores the way in which policy changes number of fatalities was very small. The were sought by the local authority and others implications for the longer term, such as through a Scrutiny Inquiry. The Inquiry was damage triggered by road subsidence, mental intended to address all the relevant issues stress and other contingent causes cannot yet be locally and nationally, including very fully evaluated, although estimates of the total significant matters associated with future costs range upwards from about £3 Billion. planning for flood-prone areas and flood Some economic impact is expected to be management, and the potential deployment of permanent, with businesses unable to re- sustainable drainage systems (SuDS); it establish themselves. Moreover, the flooding represents one way in which flooding policy is also threatened to trigger community unrest on being influenced in the UK today. The author a scale rarely experienced in the UK. was privileged to participate in the Inquiry as an independent Technical Advisor to the Legitimate questions are being asked nationally Scrutiny Panel, and thus had access to both about how damage such as this can be experienced in the developed economy of the

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UK, with more than half a century of planning light of these uncertainties. In today’s parlance, guidance on the management of flooding and these are the general characteristics of many flood-prone areas. To explore this, problems associated with sustainable Gloucestershire County Council established a development and progress towards Scrutiny Inquiry that investigated the causes of sustainability, and they provide an appropriate the flooding, and the managerial lessons that framework for considering the events of 2007. could be learned from, and by, the various agencies and stakeholders The physical background (www.gloucestershire.gov.uk). The main phase The scale of inundation of the Gloucestershire of the Inquiry ran during the autumn of 2007, event was unprecedented in historic times. collecting a substantial volume of evidence and Record levels of rain fell in the late spring and itself informing the continuing national review early summer of 2007, bringing soils to field of flooding in the UK, chaired by Sir Michael capacity in late June and triggering localised Pitt (www.cabinetoffice.gov.uk). Its pockets of flooding. From 1st June to 31st recommendations are being followed up during August, between 200 and 250% of the 1971- 2008, with the first analysis of progress having 2000 long term average rainfall was recorded occurred in January. However, whilst definitive over almost all the county. Around Pershore, conclusions are not yet available, a range of Worcestershire, it was higher still, in excess of interesting issues have emerged from both the 250%. For the single month of July the Scrutiny Inquiry process, and its seventy-five majority of Gloucestershire received between recommendations, particularly revolving around 400 and 450% of the long term average, and the implications of flooding for the well over 300% was noted for the wider Severn development of the UK landscape, the future and upper Thames catchments. The resilience of its communities, and the threats Environment Agency estimated the return posed by climate change. period, ignoring the possibility of trends in the data, as something in excess of once in 200 Flooding is one of the most intransigent of years. Subsumed within this period however, on the UK’s environmental problems, with 20th July exceptionally heavy and persistent multiple causes and impacts, disagreement rainfall (some 78mm in 12 hours, peaking at about the division of responsibilities, the between 16 and 32mm per hour) fell onto the approaches and the appropriate solutions, and saturated ground. In parts of the north of the the near-certainty that it cannot ever be fully county, and in adjacent south Worcestershire, ‘managed’. More than thirty years ago, US the equivalent of two months’ average rainfall academics Rittel and Webber (1973) fell within 24 hours. Runoff was particularly characterised such complex problems as concentrated in areas draining westwards from ‘wicked’. Wicked problems usually have the Cotswolds escarpment area towards the intersecting physical/scientific and Severn channel. Countless small rivers and human/sociological dimensions, and typically urban drainage systems were overwhelmed; defy traditional linear solutions, requiring more localised and acute flash flooding occurred adaptable ways of thinking. Rittel and Webber’s which although often dissipating within a few original conceptualisation included ten specific hours, caused damage both to the fabric of traits of ‘wickedness’, but the essence may be ancient historic buildings, and to newly built captured in five or six elements: poorly properties. Strikingly, the town of Tewkesbury formulated and complex issues, competing was entirely surrounded by floodwater, water value systems, ambiguous terminology, a encroaching on the graveyard and lapping at multiplicity of actors or stakeholders, spatial the walls of the nave of the twelfth century and temporal interdependency and a lack of abbey. clear end points. Solutions are usually ‘better’ or ‘worse’ rather than absolute, and yet decisions must nevertheless be made in the

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However, the Emergency played out over a more than 500 were stranded on railway much more protracted timescale. County platforms, and significant numbers required Emergency Service ‘Gold Command’ structures airlifting or boat rescue from dangerous were established at 14.15 on the 20th July, domestic and industrial situations. Many of the bringing together key managers under one longer term implications have probably not yet principal line of management and revealed themselves. communication. The immediate impacts of flash flooding on residents and travellers The Scrutiny Inquiry as a mechanism mainly began to be recorded in the afternoon for investigation and early evening of 20th, during which time Gloucestershire County Council established the emergency evacuation and rest centres were Scrutiny Inquiry in August 2007 to inform their established, but by 22nd July major river response to both a national Select Committee flooding had also begun in the Severn, and the Pitt Review Parliamentary Inquiry. Warwickshire Avon and Churn catchments. Evidence was taken from a range of Gloucestershire’s water levels exceeded those organisations and cross examinations of invited of the noteworthy flooding of spring 1947 stakeholders conducted in ‘Select Committee’ which defined some of the early planning style through four Public Meetings. They were guidance for UK authorities. Mains water also informed by research, questionnaires and supplies were lost from Mythe Water Treatment house-to-house investigations undertaken by Plant through inundation on 22nd, and power officers, and seven further locally-based public supplies from Castlemeads substation on the meetings at which local residents could speak floodplain near Gloucester on 23rd July; to Councillors. The Local Authority anticipated Walham substation was rescued through the a wide range of outcomes for the Inquiry, intervention of the military and others with including a wish to build up a picture of the pumps and mobile barriers. Many properties types of flooding and any contributory or lost sanitation, or were affected by sewage exacerbating factors beyond the obvious contamination from surcharged sewers in low meteorological extreme, urban flooding lying ground. Consequently, from 24th July, (including building on the floodplain), the priorities began to switch from emergency implications of having key infrastructure rescue to the provision of safe drinking water located on floodplains, and the responses of supplies to about 350,000 people, and by the emergency services. There was a particular following day some 900 bowsers were in focus on ‘lessons learned’, potential operation, sourced from across the country. By improvement of resilience and the opportunities 27th, approximately 3 million litres of water to share good practice, and reassurance of local were being delivered into the county daily by communities. One severely flooded area, bowser and bottle. This figure rose steadily Longlevens in Gloucester, was selected as a over the following days, and safe mains case study to establish in more detail how the supplies were not fully restored for almost three various elements of the Emergency had weeks. At its peak, the drinking water demand interacted. It is notable that landscape planning was over ten times that specified in national issues were explicitly included in the remit at emergency planning contingencies. the outset, as representing crucial elements of The event formally moved from understanding. Consideration of sustainable ‘emergency’ to ‘recovery’ mode on 6th August, drainage systems was implicit, reflected in but many Gloucestershire residents are still in requirements to examine ‘urban flooding and temporary accommodation eight months later. all associated matters’, identify good practice, Approximately 4000 houses and 500 county and to ‘identify, if appropriate, whether there businesses reported experiencing flooding; are opportunities in the recovery process to 10,000 drivers were trapped in floodwaters on improve the resilience of the county’s the M5 motorway for up to eighteen hours, infrastructure’.

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The published role of the Council’s participating Councillors developed and the ‘Overview and Scrutiny’ arrangements is to later questioning was notably more effective in hold the Council executive (the Cabinet) to drawing out significant issues. account before and after decisions are made, although in this instance the remit was much Report structure wider, including exploration of the background The final Scrutiny Inquiry Report covered facts and the responses of many agencies. The issues relating to six principal themes: the Inquiry was therefore led by a cross-party emergency response; watercourses, drains and group of elected Councillors, supported by sewers; land use planning process; single points senior officers and a Technical Advisor, and of failure; communications; recovery and future reporting back to the full Council in November resilience, including local people and 2007. Participating Councillors were not communities. As published specialists in the consideration of flooding (www.gloucestershire.gov.uk), it also included issues, and the technical advice therefore seventy five recommendations, the written covered issues such as definitions of the terms evidence from over twenty stakeholders, ‘floodplain’ and ‘watercourse’, opinions on the verbatim transcripts of the four public appropriate grouping and sequencing of meetings, recommendations for action made by questions, and advice on the overall structure of other bodies, and summaries of the written the final Report. A number of the Councillors feedback from the local public meetings. In a had extensive experience of planning matters, short paper it is inappropriate to outline all of and all were very familiar with the local the points, but specimen recommendations geography and landscapes of their ranged from minor but locally important constituencies. However, noone was initially aspects of implementation of policies such as familiar with the guidance contained in public those contained in the Council’s own Major policy and consultation documents such as Flooding Emergency Plan, through to issues of DEFRA’s ‘Making Space for Water’ (2004), or wider interest including the implementation of the details of Planning Policy Statement 25 on national planning policy and guidance. Development and Flood Risk (2006). Comments included recommendations on, for instance: Twenty-one invited witnesses appeared at the Inquiry, including representatives from all The Emergency Response: the major District Councils, the Environment Agency, utility companies, emergency services • Adequacy of flood warnings. (including Fire and Rescue), community • Adequacy of Gloucestershire County services (including those with responsibility for Council’s Major Flooding Emergency Plan. vulnerable people), planners, economic • Variations in policies for the distribution of development agencies, community groups and sandbags. the media. A local developer and Central • Provision of an alternative water supply. Networks (an electricity distribution company) declined the invitation to appear, but representation was in general excellent, and all Communications the aspects of the Emergency which the Inquiry Numerous examples were cited of where wished to pursue were able to be explored, communications could have been improved, albeit over a relatively brief period. Of the early including… witnesses, the Environment Agency, agreed to reappear later to facilitate understanding of the • Engagement of key agencies in the complexity of the issues. As the Inquiry production of the County’s emergency flood progressed, the experience gained by the plan. • Communications with the media (initially).

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• Misleading communications with the public, notably poignant. But for the most part the from within and outside Gloucestershire, on evidence collected appeared rational, honest issues such as the extent and the lack of and appropriately detailed. drinking water and the potential evacuation of Gloucestershire. Major lessons learned – landscape issues Single Points of Failure One of the most dramatic lessons learned from • The need for utilities to work more the Gloucestershire flooding was the effectively with the Local Resilience Forum unexpected vulnerability of ‘single points of and ensure that key agencies are aware of all failure’ such as water treatment plants and risks to the County’s critical infrastructure electricity substations. For largely historic and have in place and have in place adequate reasons, these are often located on floodplains. emergency and business continuity plans. More robust forms of flood protection for such utility nodes were viewed as essential and • The need for utilities to invest in permanent urgent by the Scrutiny team, with development flood defences if key infrastructure is to of secondary supply possibilities being remain in its current location. desirable wherever reasonably practicable. Other parts of the Scrutiny Inquiry Report Recovery and Resilience concerned matters principally of local interest, • The impact of the flooding on the albeit that their consideration provided a wealth psychological and emotional well being of of information about tactics and best practice families affected. when viewed alongside comparable issues arising from related investigations in Hull and • In terms of future resilience, the ability of Yorkshire. However, it is in the arenas of individuals and local communities to be planning policy and floodplain development, more self reliant in situations where the and in the potential for promoting emergency services and other responders are implementation of sustainable drainage systems occupied beyond the ability to deal with all (SuDS), that the Inquiry had most potential to the calls being made upon them needs to be impact national policy. developed. In relation to the planning process, a key Watercourses, drains and sewers remit of the Inquiry, it reported • Lack of a body to coordinate/assume overall ‘The Inquiry has examined the issue of responsibility for maintenance of developments on the floodplain, and the role watercourses of the Environment Agency in the process. • Adequacy of highways drainage However, the Inquiry has not been able to • The lack of knowledge of the overall investigate this complex issue in detail and capacity of the County’s drainage systems is therefore proposing a further task-group to tackle issues relating to flood risk, land • The impact of new developments on existing use planning and new developments’. drainage systems Despite its caution, the Inquiry did nevertheless Occasionally the Inquiry explored themes that review elements of this issue, considering attracted a degree of amusement, such as the Planning Policy Statement 25 (2006), the deliberations on the source of misinformation Regional Spatial Strategy and the roles of local concerning the apparently imminent evacuation planning authorities and the Environment of the county in late July. By contrast, some of Agency in local decisionmaking. There was the evidence, particularly on the psychological particular concern about the number of impact of flooding on vulnerable groups such applications for new properties to be built as young families and elderly people, was

123 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 within the 1 in 100 year limit on the floodplains levels during house construction, an intrusive of Gloucestershire’s major rivers, which gas pipeline crossing, groundwater seepages seemed to show a rising trend. An estimated and blocked unadopted surface water drains 20,000 people live on the floodplain in the installed to entirely inadequate specifications. county currently, and between 150 and 180 new The Inquiry heard disturbing testimony from properties are now being constructed every residents, and views from the various agencies year; almost 1,100 vulnerable properties have with responsibilities for urban planning and been built within the last fifteen years. During emergency responses. Several Councillors also this review, both the Environment Agency and had relevant local knowledge of the problems, the South West Regional Assembly came in for but despite this the evidence base upon which some implied criticism, especially regarding to unpick the intricacy even for this one site, their role in policing, promoting or restricting was clearly insufficient. successful applications to build. In the Report, ten hypothetical questions were posed about the Contaminated water reached depths of about implementation of planning policy, including a metre inside houses and cars in Cypress around ‘short-termism’, the appropriateness of Gardens in June, and again in July when many using the modelled 100 year flood boundary as residents were living elsewhere awaiting a limit, and concerns about whether fear of the completion of repairs. Some properties survived cost of litigation predisposed local authorities almost unscathed; the occupiers of the others to agree planning permissions. Because of the were left distraught, particularly disabled difficulty of challenge, the Inquiry residents and those owning bungalows or who recommended establishing a task group to look had lacked the means to rescue personal further at these issues; this has yet to report. possessions from the rapidly rising mixture of water and effluent. Even articulate members of There are hints of the challenge of this the community group that emerged following complexity not only early in the Report where the June event were ambivalent about whether the impact of new developments on existing they were aware of any flood risk prior to drainage systems are noted as being worthy of purchase. Their preferred outcomes afterwards further exploration, but specifically in the case were similarly undecided; some wished for study of Longlevens flooding. A small compulsory purchase of their property, some residential estate was constructed at Cypress for financial compensation, and others for Gardens in 2001 on the floodplain of the lower engineering works to ‘prevent’ future flooding Horsbere Brook. The Brook is a minor events, but perhaps not at the expense of the watercourse running westwards from the streamside views which had initially attracted Cotswolds escarpment through the built up area them to this location. Norton (1975), in an of suburban Gloucester, down through a excellent theoretical analysis of Rittel and restricted culvert under a major road and thence Webber’s (1973) work refers to this into the Severn. The upstream part of its characteristic of ‘wicked problems’ as ‘value catchment is partially impounded. The lower pluralism’. Moreover, some of the residents, floodplain includes a sewage pumping station even in this small centre of population, that failed to perform to specification during suggested solutions that potentially impacted the heavy rainfall of both June 25th and July adversely upon others in the same community 20th, allowing sewage from a substantial part or beyond, a manifestation of the spatial and of the city of Gloucester to back up and flood temporal interconnectedness of wicked Cypress Gardens. Alongside this, the channel problems such as flooding. overtopped, probably as a result of both rapid upstream urban runoff and the downstream Major lessons learned – Sustainable channel constriction. There were also contested allegations about inadequate river channel maintenance, lowered river bank and ground

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Drainage System (SuDS) issues Urban (sic) Drainage Schemes, and what can be Although ‘sustainability’ was only touched done to ensure the upkeep of SUDS once they upon briefly in the Gloucestershire Scrutiny are in place?’ Inquiry, SuDs, tautologically perhaps, represent Evaluating the Inquiry process as a part of a sustainable approach to flood management. Whereas planning policy is means of addressing flooding principally directed at mitigating the risks The main body of the Report, although written posed by flooding from large rivers, SuDS by Officers informed by legal and technical designs offer some possibility of physically advice, was based on the evidence collected reducing the peak flows from developed sites, and agreed as part of the democratic Scrutiny amongst other benefits (Environment Agency, process by the elected Councillors. In practice, 2005; Wilson, Bray and Cooper, 2004). In this the speed of its production precluded major regard, SuDS philosophy is one of a limited alterations by Councillors to the draft of the repertoire of soft engineering ‘solutions’ to text, although later consideration by other flooding currently favoured by national policy. stakeholders and full Council offered a Despite this, their implementation and theoretical chance for adjustment. For the most deployment in England have so far been limited part this was not seen as necessary, and the despite the adjacent South Gloucestershire opportunity not taken up. The only major authority’s pioneering work queries and suggested amendments emerged in (www.southglos.gov.uk). relation to complex planning and landscape issues, where Tewkesbury District Council Immediately after the flooding, the County robustly attacked the accuracy of the figures Council’s research team undertook a household describing the numbers of properties permitted questionnaire survey to establish the locations to be developed on the floodplain within recent of affected properties. This was enhanced by years. A correction was issued, but the revision studies of businesses done by the South West was anyway minor and did not alter the sense Regional Assembly and Gloucestershire First, of the Report. and from additional information secured through public meetings. Notwithstanding its It is very apparent that landscape-related effort, the Inquiry remained unable definitively issues and consideration of the potential of to identify the location of all flooded properties. SuDS were generally less well handled through Excellent satellite images and aerial the Scrutiny Inquiry process than other more photography have allowed the Environment local and emergency operational issues. This Agency to make adjustments to the mapped was partly the result of the democratic process limits of flooding from the major rivers, but that established and managed the Inquiry. despite the damage inflicted by flash flooding Councillors’ enthusiasm for, and dedication to from urban runoff, it strikes small areas and the task was exemplary, and the chairing was dissipates relatively quickly. Mapping its extent outstanding. Their grasp of the mechanisms of proved too challenging in the available time. local authority management, the nature of their Because of this, the Scrutiny Inquiry constituencies, and the implications for flood Councillors were unable to evaluate the relative risk of various climate change scenarios, was extent to which flash flooding was responsible impressive. By contrast, participating for damage, and hence the extent to which Councillors expressed contradictory views on SuDS might address local flooding issues, and the significance of the different planning issues; improve community resilience. The final their understanding of the scientific background unanswered question in the landscape section varied, and some struggled with the spatial and of the Scrutiny Inquiry Report therefore temporal interrelatedness of different flood concerned SuDS. It asked ‘What is done/what management strategies, scientific and statistical can be done to encourage the use of Sustainable uncertainty, and the poor formulation of the ‘flooding problem’. The relative weighting and

125 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 proximity of multiple layers of flooding cessation of all floodplain inundation, which is ‘causes’ also proved problematic. The statistical unrealistic under almost all future scenarios, likelihood of recurrence of the event is climatic, financial or otherwise; for others, apparently low, but the concept of accepting holding the damage down to the current levels future inundation in very extreme events rather in the face of climate change, or success in than tackling even such a low level of risk directing floodwaters elsewhere away from through engineering works, proved major settlements, albeit at the expense of uncomfortable. Individual Councillors tended certain individuals, is probably sufficient. towards different views on the appropriateness of ‘community responses’ versus ‘centralised A Scrutiny Inquiry provides a theoretical responsibility for action’ and the responsibilities forum for stakeholder discussion towards a of individuals; they were split along lines consensus, where the competing apparently more related to individual prior understandings, interests, priorities and experience than to party political affiliations. constraints can be articulated. In this instance, the Inquiry presented an opportunity to Under these circumstances, and in the articulate the flooding emergency problem limited time available, it was perhaps easier for concisely, and agree the shared language. The the Inquiry to revert to critique of the detailed resultant Report can be seen as the consensus arrangements for distribution of sandbags and views of the participating Councillors, even if assertions about the apparent inadequacy of not those of all the witnesses and other river channel maintenance, where there are stakeholders; its acceptance by the whole somewhat clearer lines of responsibility, than to County Council also presumes some sort of reach general conclusions about management of democratic agreement. This is a step towards flooding from the complex range of the social learning approach to resolution which geographically unique examples displayed is at the heart of recent approaches to decision across the County. making for sustainability (Collins and Ison, 2006). Conclusion However, analysis of the process reveals The Gloucestershire Flooding Emergency of some of the complications of making this 2007 is an excellent exemplar of the approach work effectively. There can be some complexities involved in untangling ‘wicked optimism that the Scrutiny Inquiry process, problems‘ (Rittel and Webber, 1973). It exhibits including the Public Meetings, emphasised the all of the characteristics of poor definition, lack social impacts of flooding, and recognised the of boundaries (spatial, temporal and thematic), variety of values represented across all of the multifaceted interaction between human and stakeholders, as well as scientific and physical systems, and multiple stakeholders, engineering matters more usually promoted by viewpoints and attitudes. As Rittel and Webber water management professionals. It allowed pointed out in their original paper, given these iteration of views amongst the participants, and difficulties of characterization, it is challenging fostered movement of attitudes and views. As to agree what a desirable outcome might be, or such, it was an appropriately adaptive and when it has been reached, and the resolution participatory way of addressing a wicked process will only be likely to end when the problem, and it provided a number of resources are exhausted, the stakeholders lose potentially valid solutions to many of the interest or the political realities change. All the challenges associated with the Emergency. In Inquiry participants appeared to agree that the accordance with the optimism of the initial level of damage sustained in Gloucestershire in remit, some lessons may have been learned. July 2007 was unacceptable, although in another forum this might itself be a more The major strategic issues of land use readily contested position. For some planning for sustainable and resilient stakeholders, the solution could only be the communities, and the possibilities afforded by

126 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 sustainable drainage systems in this process Norton, B.G. (2005) Sustainability: a were, however, not fully addressed and philosophy of adaptive ecosystem management, certainly not resolved. The ambiguities in the 608pp. University of Chicago Press, Chicago. views of stakeholders, the lack of confidence in the group’s ability to engage with larger Pahl-Wostl, C. (2006) The importance of social questions, and the limitations of time militated learning in restoring the multifunctionality of against success in these realms. Scrutiny rivers and floodplains. Ecology and Society, Inquiries are therefore perhaps best seen as a 11(1), 10 and significant contribution towards newly http://www.ecologyandsociety.org/vol11/iss1/art emerging governance mechanisms for water 10/ (Accessed 22nd February 2008). (Collins and Ison, 2006), rather than as a Pitt, M. (2007) Learning lessons from the 2007 complete solution. floods: An independent review by Sir Michael Pitt. London: Cabinet Office, and Bibliography http://www.cabinetoffice.gov.uk/thepittreview Collins, K. and Ison, R. (2006) Dare we jump (Accessed 22nd February 2008). off Arnstein’s ladder? Social learning as a new policy paradigm. Proceedings of the Rittel, H. and Webber, M. (1973) Dilemmas in Participatory Approaches in Science and a General Theory of Planning. Policy Sciences, Technology Conference, 4th-7th June, 2006, Vol. 4, pp 155-169. Elsevier Scientific Edinburgh. Publishing Company, Inc., Amsterdam. Department for Environment, Food and Rural South Gloucestershire Council (2002) Affairs (2004) Making Space for Water: Sustainable Drainage Systems: A Guide for Developing a new Government strategy for Developers, flood and coastal erosion risk management in http://www.southglos.gov.uk/NR/rdonlyres/B3F England – a consultation exercise, 154pp. CCCC9-D395-4B4B-8E47- DEFRA, London. 6B06EA3773C9/0/PTE020003.pdf. Department for Communities and Local Wilson, S., Bray, R. and Cooper, P. (2004) Government (2006) Planning Policy Statement Sustainable drainage systems: Hydraulic, 25: Development and the flood risk, 50pp. structural and water quality advice, 324pp. HMSO, London. CIRIA, London. Environment Agency (2005) Sustainable Drainage Systems: A guide for developers. Environment Agency, and http://www.environment- agency.gov.uk/commondata/acrobat/a5_suds_v3 .pdf (Accessed 22nd February 2008). Gloucestershire County Council (2007) Scrutiny Inquiry into the Summer Emergency 2007, http://www.gloucestershire.gov.uk/index.cfm?ar ticleid=17502. Johnson, C.L., Tunstall, S.M. and Penning- Rowsell, E.C. (2007) Crises as catalysts for adaptation: Human response to major floods. Flood Hazard Research Centre Publication No 511, 189 pp.

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Floods and Water: A Landscape-Scale Response Ian D. Rotherham Sheffield Hallam University

Introduction: Climate, Weather and tarmac and concrete. But there is more: our Floods impacts haven’t been restricted to the built environment; we have drained and ‘improved’ Weather and climate clearly influence flood- huge areas of farmland. Drainage was an risk and storm damage in many, though not all, obsession of the Victorians. From the highest situations. However, the relationships and parts of the Pennines, the North York Moors, trends are not simple. In addressing the and mid Wales with their ‘gripping’, to the problems and issues it is important to recognise lowlands of the Vale of York, the flatlands of that flood and drought are flip sides of the same Doncaster, the Severn Valley, and the issue. A flood today does not diminish the Cambridgeshire Fens, the story is the same; chances of a drought tomorrow. It is clear that drain, drain and drain. Farmers have been the ‘the rules of engagement’ between people, driven by government polices over decades, by weather and landscape have changed. In the massive subsidies from EU and UK future we will need to plan in order to absorb governments, and by public demand for the effects of a more extreme climate, and this evermore cheap food. However, there is now a extends not just to infrastructure and cost. With our rivers straightened and canalised, engineering, but to the wider landscape too. they are now locked into artificial banks, and Landscape change has clearly generated some the natural drainage systems are de-coupled flooding problems, and at the very least, it has from their floodplains. The latter are massively exacerbated the risks through bad weather and reduced or totally removed. Rivers are mostly through development-related impacts. lined by intensive farming which grew rapidly from the 1950s to the 1990s. This was especially the case in flood-risk areas such as throughout the Severn, the Vale of York, the Rother Valley, the Don Valley, and similar landscapes throughout Britain. In other areas, localised but significant, the riverbank has been sacrificed to urban city heartlands and industry. If this wasn’t enough, in recent years we began to build anew on former expansive floodplains, Floods at Oxford 1852 the natural control systems of Britain’s lowland landscapes. To add to the problems, our increasingly extreme weather is dumping Climate manifested in the weather is unbelievable quantities of water on to changing; getting more extreme, both hot and vulnerable areas, and in short, intensive dry, or as we witnessed in 2007, torrential periods. As we experienced this summer, deluges of rain. There are other factors too and though, the heavy rain is coming in the midst of in particular the way people have changed the longer, persistent rainy periods. Consequently landscape over the centuries. So over hundreds the ‘natural’ landscape can’t cope, and the built of years, but increasingly during the late structures are at their limits or beyond. With twentieth century, we have changed the what we’ve done, this is hardly surprising. environment in which we live, work, and recreate. Urban areas have sprawled out over floodplains, turning soft, porous surfaces to

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There is a further worry for those living or erosion and cutback, and in woodland areas for working in many of the lower-lying coastal example there is a loss of woodland ground- zones, with the additional threat of climate- flora and sometimes dieback of mature trees. induced sea level rise. Yorkshire around Hull The impacts are also manifest in massive and Holderness for example, or in the south- erosion of topsoil down to a ‘B’ horizon that is east areas around the Thames Estuary are all at panned and sheds rainwater very rapidly, and risk. For areas already at or even below sea this is compounded by removal and burning of level, this is a serious menace in decades to turf and vegetation by charcoal burners for come, and of course the south-eastern seaboard several centuries. All these woods suffer of Britain is also slowly sinking anyway. A desiccation and drought, and detailed case- combination of a North Sea surge as happened studies confirm the main agents of de-watering: in 1953, but more recently without incident in autumn 2007, and inland rainfall as experienced • Woodland internal drains still active and in South Yorkshire or Gloucestershire in desiccating; many actively maintained and summer 2007, could be devastating. With ever- even enhanced during the twentieth century increasing urban development in these areas amenity woodlands phase. too, the hydrology is compromised and people • Continuing drainage maintenance associated and property are increasingly at risk. There is a with recreational and amenity uses and huge and growing literature on this topic with perceptions of an urbanised population. extensive and deeply researched assessments • Urbanisation and ‘water theft’ have left and guidance (e.g. Anon.1-5). Yet despite all woods as isolated islands of habitat; now this discussion and research, the problem is yet more-or-less surrounded by development to be solved. and roads, services and drains sunk into trenches and beds of aggregate. Soft surfaces Hydrological Trends extensively replaced by tarmac and concrete. There have been numerous studies of • New urban developments impacting on hydrology and catchment behaviour, and much surface drainage. excellent and rigorous science applied. However, the subject often lacks a multi- disciplinary approach and some key aspects of Bowden Housteads Wood, a medieval ancient catchment behaviour and especially of urban woodland on the south-eastern outskirts of impacts are generally overlooked. Some Sheffield, and part of the Lower Don and modestly funded projects on the case-study Rother catchments so badly affected by the Sheffield area have proved interesting, though a 2007 floods, is a ‘good’ example of these lack of funding limited any ability to follow impacts. The final phase of deterioration was these up in the necessary detail. Studies of the brought about in the 1990s by the large ASDA impacts of urbanisation on woodland hydrology shopping centre adjacent to the southern were undertaken in the Sheffield area in the boundary of the woods. Following this 1990s, as part of a wider study of regional development the area of woodland remaining hydrology and urban impacts (Griffiths et al., relatively intact in terms of hydrology and 1995 &1996; Griffiths & Rotherham, 1996a/b). ground flora, has completely deteriorated. The study came about because of observed Whatever the local planning authority’s polices changes and anecdotal evidence of major are on sustainable water management, in this deterioration in catchment quality and case they have certainly failed dramatically. behaviour. It was noted that many of the The development includes little green space smaller tributaries in the urban catchment in and it appears limited if any, porous surfaces or particular, were completely dry during much of soakaways. the year, and also suffered from severe flash- flooding when rain occurred. The stream channels experienced rapid and damaging

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A key issue arising from the Sheffield drainage have had major effects. Parallel research in the 1990s was the impact of service investigations were undertaken in the Peak networks such as cables and drains in aggregate District moors, based largely around a seminal beds, and acting as subterranean drainage study by Paul Ardron, of the impacts of systems. Combined with impermeable surfaces medieval and later peat cutting (Ardron et al., and deliberate drainage, these have a huge 1998). Yet despite overwhelming evidence for impact on water behaviour. Despite policies on the impacts, the response from the Peak Park hydrological sustainability in both urban and Authority’s ecologists, to the idea of blocking rural areas, there is little positive action and drains in the two major peat bogs of the desiccation continues. In the regional study, National Park (both with raised bog elements), wooded landscapes, urban and rural, all suffer was viewed with scepticism. Some work was water-loss. The sites, often severed from eventually undertaken on Leash Fen, but only cultural and environmental origins, survive as after the intervention of a senior researcher isolated habitat-islands in often inhospitable from the then Nature Conservancy Council. landscapes. Long-term drought is responsible Moors for the Future are now pressing ahead for significant ecological trends away from with significant restoration work on the Dark their ancient woodland origins with many Peak. However, there remain many woodland indicator species now isolated and opportunities across the whole of the Eastern vulnerable (Bownes et al., 1991). The other Moors complex to remediate historic drainage problem identified was that a fairly typical and to enhance water retention. Indeed, it is engineering hydrology approach to the likely that these will have more impact on the assessment and modelling of these small urban lower catchment behaviour than the major sub-catchments was problematic. A relatively works on Kinder Scout and Bleaklow. experienced team consisting of a professional, former Yorkshire Water engineer and a post- Areas at Risk and Positive Planning doctoral geographer hydrologist produced Beyond the increasing risk of inundation across original results then seriously misrepresented the wider landscape, there is a specific worry the landscape and its history, and especially for those living or working in many of the factors such as greenspace sub-surface lower-lying coastal zones, with the additional drainage, and even a 1940s shallow opencast threat of climate-induced sea level rise. coal area. This led at first to serious errors in Yorkshire around Hull and Holderness for the assessment. The other problem was that the example, or in the south-east areas around the standard modelling applied was too crude to Thames estuary are all at risk. For areas already cope with the within-catchment micro- at or even below sea level, this is a serious hydrological behaviour of water; important in menace in decades to come, and of course the catchment behaviour but critical too for south-eastern seaboard of Britain is also slowly ecological sustainability. The assessment for the sinking anyway. It is not just in the coastal zone Gleadless Valley, a sub-catchment of the River that people are now at risk. Across huge areas Sheaf, indicated only a modest decrease in of landscape, the natural wetlands have been stream flow between around 1920 and the late removed and replaced by intensive farming, by 1980s, when the area was totally urbanised. Yet industry and commerce, and often by housing. anecdotal and map-based evidence indicated In South Yorkshire alone, 99% of England’s streams that by the 1990s were bone dry, but third biggest fenland has been destroyed, and were previously full and even had features such most moorland removed or drained, much as waterfalls. funded by the public purse. There are now pioneering developments, such as the RPSB Similar problems exist for the assessment Old Moor Nature Reserve in the Dearne Valley and modelling of small rural catchments such and the Potteric Carr Nature Reserve in as the Moss Valley in North Derbyshire, where Doncaster, that begin to help reinvigorate this woodland gripping and agricultural field

130 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 landscape. But whilst these major new wetlands risk may be trapped and unable to move. helped lessen recent flood impacts, they are not Realistically, after all that has happened, who is enough. going to move into a flood-risk zone? If willing buyers are found, then they surely will not pay So the question is what must we now do? To the market prices that would have been solve the problems, especially if climate change expected prior to the latest floods. House values accelerates as seems likely, we need radical, and saleability will fall. To compound the far-reaching actions. These should make suffering, there are serious questions about sustainable drainage systems compulsory for whether home-owners will be able to get or at major new developments, going beyond flood least afford, flood damage insurance. Again, if protection. It is not enough to demand an they can’t, then in future, fewer people will risk absence of a negative impact on flood risk in a living in flood zones. This is a controversial floodplain. In future it will be necessary to issue since, although the intensity of recent ensure that all developments make positive events has been surprising, the catastrophes are contributions to water management, or else to a degree predictable. We have suffered major Planning Permission should be refused. floods and storm damage since time Obviously this applies mainly to larger immemorial, and historic records document developments, but all housing and business these back over a thousand years. Indeed, premises can make a contribution across the whilst individual incidents cannot be reliably whole catchment. This need not be draconian or forecast, they were to an extent predicted by prohibitively expensive. For smaller premises, both environmentalists and planners. Planning simply including soft and porous surfaces, and reports back in the 1920s for example, warned perhaps where appropriate soakaways, would specifically against building on Yorkshire’s be sufficient. floodplains in the old West Riding (including South Yorkshire). This, along with similar advice given ever since, was largely ignored. We know that building on flood plains is a bad idea, but we go ahead because it is easy to do. There are both immense short-term financial gains for developers and landowners, and these are coupled with acute housing shortage and huge pressure for new developments. The local authorities are charged with protecting communities against flooding but also with providing enough new homes; the horns of a dilemma. In some localised areas, it may make Tyneside early 1900s sense to help residents move to a new, safer location, rather than continuing to face a losing The years to come will undoubtedly see battle with the elements. This may not be what massive investment in the engineered people wish to hear, and will be a hard truth to infrastructure that manages water and combats bear. However, the principle has already been floods. This will include barriers, established in terms of the abandonment of embankments, upgraded drainage systems and active protection of some coastal zones that are the rest, costing millions of pounds. At the at risk and now considered indefensible. same time though, there is still the threat of further development on the floodplain, nature’s Paying for the Landscape water management system. So we are In July 2007, I spoke with Stephen Watkins, a essentially working against the grain of nature farmer near Tewksbury with 1,500 acres under and not with it. The human suffering and flood water. Stephen’s argument was that if he individual dilemmas then kick in, and those at and his neighbours had not allowed their land

131 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 to flood, then the consequences downstream and the continued distress and suffering of would have been even more catastrophic than home-owners and other across the region. To they were. Indeed, it is likely that major remediate the damage of centuries of utilities such as the Gloucestershire power environmental degradation, the longer-term station, which were so close to flooding, would solution must be landscape-scale, and centred have gone down. The impacts of this would around those who manage the landscape, i.e. have been appalling. However, he and his our farmers. In this context, in recent years neighbours soaked up the floods at their own there’s been much talk about how farmers are expense and the greater catastrophe was ‘custodians of the countryside’ and that they averted. But surely, as the costs and the human should be rewarded for this role. It is time to tragedy of the events were lessened by the deliver on such talk. Changes in EU funding to farmers’ actions, we as the wider community Single Farm Payments and Environmental should foot the bill. Isn’t this what ‘farmers as Stewardship are moves in the right direction custodians of the countryside’ is all about? and towards broader outputs rather than just food production. However, it still seems there is Effective Responses a gulf between policy, need, and action. In the short-term, engineering is a vital part of any effective response, to avoid system overload in drains and channels and to protect critically ‘at risk’ services such as power and water. This is a part of the solution but not in itself a long-term, sustainable option. In many situations this is a case of treating the symptoms not addressing the causes of the problems. It is what I call the sticking plaster approach, and not curing the underlying problems of water management. In the short- term, targeted engineering is all we have got, but we must now learn from recent experience. Furthermore, we must plan for even more Rother Floods 2007 © Christine Handley extreme events to come. This means taking the threats seriously and planning accordingly, and Importantly too, with an increasingly urban long-term. We must learn to ‘work with the population often disengaged from the farming grain of nature not against it’; but what does world, there remain serious problems in getting this imply? On the one hand I suggest that the effective message across. It is surely no appropriate sustainable drainage systems coincidence that recent years have seen many become mandatory on all new developments. families going out of farming after generations These will vary with locations and with specific on the land, and serious difficulties in recruiting conditions, but the technology is there, it just new people to the industry. Ask any agricultural needs to be applied. They include recent college and they tell a tale of falling numbers innovations such as green roofs. Again this will coming to train in mainstream agriculture. One not be enough but only part of the solution. of the principle problems seems to be in Like the boy with his finger in the dyke, we recognising the central role of farming in need something more sustainable, and the key delivering on the issues and outcomes high on players in a more secure future will be farmers. political and popular agendas. There’s much We need to work with, and pay farmers, as written, and there are endless policies, on custodians of the landscape, to manage their sustainability, on responses to climate change, land to hold back the floodwaters. This won’t and on quality of life, and even rural be cheap, but it will cost less than the renaissance. But one struggles to find how alternative of repeated damage and disruption,

132 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 farmers and land managers are identified in address opportunities both large and small, for these as the core group of people tasked with positive water management. Some of this delivery. They are not. It seems that neither the involves a critical look at planning zones and farming industry and community, nor the wider procedures. There should be no more floodplain public have grasped the fact that it is land developments unless absolute need is managers who must deliver a more sustainable demonstrated. But beyond this, all significant future. To do this requires vision, skills, and a new developments, whether on the floodplain vibrant community of professionals, including or not, should guarantee a positive impact on farmers and foresters. The issues range from water management. This is a shift from the idea changing farm practice and all the hotly- of simply demonstrating the absence of a debated matters of carbon footprints and offset, negative impact, to positive management for but also the more tangible things such as the water. The location of critical infrastructure management of water, and the sustainable should, where possible, not be sited within a production of good quality food. So here’s the floodplain, or if it is, then measures should be rub. What has happened to all the talk of adopted to offset flood water elsewhere close paying the farmer to manage the flood? What by. The Gloucestershire situation in 2007 could happened to proposals to extend woodland have been much worse; without Stephen cover to help mop up excess water? When York Watkins and his farmer colleagues the waters was badly hit a few years ago, and then areas would have risen the extra inch and the around the Severn Valley were also affected, it electricity sub-station would have gone down. was said that the solution was, at least in part, That extra inch may be the key. The approach to pay the land manager for ‘an ecosystem needs to include innovative developments such service’. We can even calculate a monetary as green roofs, soakaways, swales, and porous ‘worth’ of such services with a toolkit provided surfaces – as the rule and not the exception. by the former Office of the Deputy Prime However, it also needs to address the 1.3 Minister; but the necessary steps simply are not million hectares of agricultural land in England happening. It is clearly possible to target major and Wales that are on floodplains and the landscape change both positively and quickly, extensive areas of woodlands and plantations when we want to. The evidence is there along too. the M42 motorway of the excellent work of the New National Forest; extensive planted woodlands and ponds, marshes and other vital habitats. All created over less then twenty years. Planning for Sustainable Solutions Each storm and every flood is a sexy media event, but once it has passed the spotlight shifts. Bodies such as the RSPB and Natural England are now pushing on with big proposals to create large wetlands in coastal zones and inland areas such as the Cambridgeshire Fens. Rother Floods 2007 © Christine Handley Initiatives such as the Great Fen Project are embedded in wider visions from organisations In the wider catchment there needs to be a such as the Wildlife Trusts (for example long-term programme of environmental re- Eversham, 2007, and Stoneman, 2007/2008). construction to remediate for decades and even These are exciting projects, but will still not be centuries of damage. This cannot be achieved enough. A long-term sustainable solution will overnight, but there are signs of things moving need to be bigger and even more radical. This in the right direction. From Peak District needs to be at a wider catchment scale, to

133 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 moorland restoration to lowland fen re-creation, Conclusions there are projects that begin to halt the damage. Tree and woodland management will also be a SOME KEY POINTS ABOUT FLOODING: part of this bigger picture. We know that at a catchment scale, trees and woods can help 1. Historic loss of wetlands and massive moderate water behaviour and we need to drainage of landscape, for example 99% harness this knowledge to enhance sustainable of the South Yorkshire Fens, and most water management. We also know that trees can moors and heathlands removed or moderate the excesses of climate change at a drained. These are long-term changes but local urban level, perhaps moderating summer the impacts have probably peaked about temperature highs by several degrees. Perhaps now. riverine floodplain woodlands will have a role 2. Intensive farming for example to play as well in holding water back and throughout the Rother Valley from 1950s- helping to reduce sediment burden in flood 1990s with the impacts of this massive water. Alongside any woodland re- drainage of farmland and simplification establishment there will need to be a of the ecosystems, driven by UK and EU programme of restoration of bogs and marshes, agricultural policies, peaking in the early again to hold back and slow down the flood twenty-first century. Even woodlands waters. This will include targeted re- across the region have been intensively construction of both long-term wetter drained over the last 200 years. landscapes and new areas for flood water 3. Straightening and canalisation of rivers, storage when the need arises. Part of what now locked into artificial banks, and de- needs to be done is the restoration of an old coupled from their floodplains. There has landscape. However, this should not be also been the almost total removal of undertaken as an exercise in looking back, valley bottom woodlands. except perhaps to learn from mistakes. What is now needed is a new and clear vision that can 4. ENTIRELY PREDICTABLE: Building - engage stakeholders, from the public and home- housing, industry, retail and offices - on owners, to the wider land owners and managers flood plains - Abercrombie 1920s warned and developers, to politicians, agencies and the specifically against building on floodplains media. This is essential because decisions need in the West Riding region. This was to be better informed, to be responsive to largely ignored. change, and accountable to those affected. The 5. Proposal with Professor Chris Baines - changes need to be approached in a positive environmentalist and government advisor way to create new opportunities rather than - to Sheffield City Council back in the barriers. A wetter landscape will provide water early 2000s to assess the River Don and as a sustainable resource, new farming Sheaf catchments to anticipate and to opportunities, new and extensive recreation and mitigate for flooding. To include major tourism opportunities and economic benefits, off-channel flood control areas in zones and it will provide ecosystem services of flood such as the Lower Don Valley, and management, biodiversity, and carbon landscape scale mitigation across the sequestration. This won’t be easy and it does whole region. The planning officers said not imply the abandonment of agriculture, of no, because flooding was under control development, or of flood control engineering. and Sheffield would never flood again. All these lie at the core of the vision, but they 6. There are associated pollution and health are placed in a context of long-term sustainable issues, and these include the re-working development. This is something that we hear a and re-distribution of industrial pollution lot about and now is the time to deliver. Only from around 200 years of heavy industry. time will tell. So, until the next time the waters rise.…

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7. There will be other impacts such as the 2. Northern Heaths and Commons Project – rapid erosion of irreplaceable promised major support by the former archaeological sites, and also the rapid English Nature but yet to deliver; dispersal and spread of invasive plants launched in Doncaster in 2004 and could such as Japanese Knotweed, across major have a big impact. catchments. 3. Re-wetting the woodlands – across the 8. Climate change is tipping the balance, region this would make a big difference – whatever the cause, and this is just the especially if combined with targeted new beginning! Drought and flood are flip woodlands in the landscape. sides of the same problem. 4. ‘Moors for the Future’ is a project taking 9. Engineering is a part of the solution but a positive approach to these issues and it is mostly treating the symptoms, not needs to be supported and extended. addressing the causes of the problems. Need to ‘work with the grain of nature not Public attitudes, debate and the media against it’. There are always issues when a long-term major change in our approach to land use is Generic Issues at a National level; proposed. In this case the upland landscape there is a need to: changes may be relatively painless due to the 1. Apply whole catchment approaches with key economic and political drivers in those blocking of grips and grains, and the areas. However, set-aside for water creation of new wetland and new management may be more problematic, since woodlands, but also of heaths and they are potentially highly productive grasslands where appropriate too landscapes for food. It is absolutely vital that 2. Provide extensive off-channel storage the farming community are brought into the from small sub-catchments to extensive equation and that a new farming emerges. From lowland areas our surveys of farmers in the region, they do not want to be paid to not farm, but they may 3. Pay for landscape management of water need to farm differently. The Water Framework 4. Have positive planning for water Directive (see Anon.3, 2002) will help guide 5. Address and resolve challenges and this too, placing more holistic responsibilities benefits such as farming and cropping on key stakeholders. However, it will be issues necessary to engage rural communities more 6. Focus on critical areas: coastal actively in landscape diversification and in the zone/major valleys and floodplains – associated economic benefits through, say, targeted protection of critical water-based leisure and tourism. In this context infrastructure it is time to deliver on ‘joined-up thinking’ rather than just talk about it. There are other issues associated with global climate change There are Regional Initiatives that and with globalisation, and these impinge could help alleviate the problems: directly on food production and land use. In particular, there will be an increased need to 1. Great Yorkshire and Humber Fen produce food efficiently from potentially Project – could have a major impact on productive land. With changing climates around carbon sequestration too, and would help the world much food production will be grow regional tourism and leisure displaced and increased stresses placed on economies. world markets and agricultural systems. With the market pressures for staples such as wheat, with demands from emerging economies like China and India, the problems may become

135 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 very acute quite quickly. However, the market problems in the context of rapid global climate forces will not remove the need to utilise change, then managing the land is surely the landscapes sustainably, and it is clear that in key. To achieve the necessary changes needs a many ways this is presently not happening. full and frank discussion with the farming Low-lying land, perhaps at or below sea level, community, and with foresters and other tree will be increasingly vulnerable to floods, and managers. It also requires money on the table to also to saline influence. Both will decrease the make the changes happen. To expect potential productivity of the land. There is an individuals such as Stephen Watkins to bear the argument, too, about pressure for primary food brunt of the waters and of the costs is production on land, but this must be balanced misconceived and unacceptable. Furthermore, against the present scenario of extensive, highly such a situation is also going to cost us all far productive arable land under crops such as more, and mean greater human suffering in the Oilseed Rape and Sugar Beet. The other group longer term. The role of the media is also of crops competing for these landscapes may be central to this process with the need to lead and those associated with biofuels. Combining a facilitate the debate, rather than trail the coat- mix of productive outputs from a wetter tails of the next disaster, and the next. The landscape may be the key to future success. problem seems to be that the debate can only Outputs might include Beef and other stock go ahead when it is ‘news’, but by then it is too such as Water Buffalo, reeds, withies, hay, and late. The scale of potential cost and of human sport, leisure and tourism. The latter can be suffering is almost unprecedented in peace- directly linked to wetlands and water and to the time, and most of the victims are the innocent wildlife they attract. These are along with victims of a corporate situation that is failing sustainable water management and flood them, and who, for the most part, have little alleviation. Historically these were wet, but understanding of why. Furthermore, in most productive landscapes and they can be again. cases there is nothing that they can do Importantly, it is necessary to assess the total individually to offset or mitigate the next economic costs and benefits of land disaster. There is no easy solution, and for both management and of development in order to politicians and sometimes the media this may better inform these debates. Unfortunately at be uncomfortable, there is no single easy cause the present time, this is simply not undertaken or solution. These, as we heard at the 2008 effectively. conference, are complex issues. Some floods will always happen, but there are ways to One problem that I have discussed with positively manage water and land, to lessen the news media colleagues is that once the flood frequency, minimise the impacts, and soften the waters recede, the media eye, and so the blow. Yet, much public policy of the last fifty political interest, slips quickly and quietly years has done exactly the opposite. Hopefully, away. Commitments made during the height of this conference and the proceedings will help the crisis are gently put aside until next time. move the debate in the right way. To quote The interest of the media also wanes as the from a recent article by Chris Hewett, Head of waters seep away, and won’t rise again until the climate change for the Environment Agency: next disaster; when of course it is too late. This is not to say there will be no action; I’m sure ‘Making Space for Water is key to adapting to there will. The real issue here is whether the inconvenient truth.’ necessary and correct actions will be taken and implemented in time to either avert, or at least minimise future tragedies. No, there will be a Bibliography review of infrastructure and I’m sure there will Anon.1 (1998) Easter 1998 Floods. Volume 2. be significant investment in engineering Report by the Independent Review Team to the solutions to flood risk at critical locations. But Board of the Environment Agency. to effectively resolve these increasingly severe Environment Agency. ISBN 1-873-16067-4.

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Anon.2(2001) Learning to live with rivers. The Griffiths, P., Simpson, F., & Rotherham, I.D. Institution of Civil Engineers, London. (1996) Hydrology and Water Quality in the Upper Don Catchment. Results of the research 3 Anon. (2002) The Water Framework Directive. feasibility study and proposals for further Guiding principles on the technical research. Sheffield Centre for Ecology and requirements. Environment Agency Bristol. Environmental Management, Sheffield. 4 Anon. (2005) Planning for the Rising Tides. Hewett, C. (2008) Making Space for Water is The Humber Flood Risk Management Strategy. key to adapting to inconvenient truth. Energy, Consultation Document August 2005. resource, environmental and sustainable Environment Agency, Hull. Management, January/February 2008, 6-8. 5 Anon. (2001) Sustainability – Development Markham, L. (1995) The Lancashire Weather and Flood Risk. Proceedings of the CIWEM Book. Countryside Books, Newbury, Berkshire. National Conference 2001, CIWEM, London. McGuire, B. (2002) Global Catastrophes; A Ardron, P.A., Gilbert, O.L. & Rotherham, I.D. Very Short Introduction. Oxford University (1998) Factors determining contemporary Press, Oxford. upland landscapes: a re-evaluation of the importance of peat-cutting and associated Newsom, M. (1994) Hydrology and the River drainage, and the implications for mire Environment. Oxford University Press, Oxford. restoration and remediation. In: Blanket Mire Degradation: Causes, Consequences and Pollard, M. (1978) North Sea Surge. Terence Challenges. Tallis, J.H., Meade, R. and Hume, Dalton Limited, Lavenham, Suffolk. P.D. (Eds.) British Ecological Society, London, Rotherham, I.D. (2007) The implications of and the Macaulay Land Use Research Institute, perceptions and cultural knowledge loss for the Aberdeen, UK. 38-41. management of wooded landscapes: a UK case- Bownes, J.S., Riley, T.H., Rotherham, I.D. & study. Forest Ecology and Management, 249, Vincent, S. M., 1991. Sheffield Nature 100-115. Conservation Strategy. Sheffield City Council, Rotherham, I. D. & Doram, G. P. (1990) A Sheffield. Preliminary Study of the Vegetation of Eversham, B. (2007) Adapting to Climate Ecclesall Woods in Relation to Former Change - An idea for our time. Natural World, Management. Sorby Record, 29, 60-70. Winter 2007, 17-22. Stoneman, R. (2007 / 2008) The Great Flood. Griffiths, P., Simpson, F., & Rotherham, I.D. Yorkshire Wildlife, Winter 2007/2008, 10-11. (1995) A Hydrological Assessment of the Meersbrook Catchment. Sheffield Centre for Ecology and Environmental Management, Sheffield. Griffiths, P. & Rotherham, I.D. (1996a) Ecclesall Woods: A Preliminary Hydrological Assessment. Sheffield Centre for Ecology and Environmental Management, Sheffield. Griffiths, P. & Rotherham, I.D. (1996b) Bowden Housteads Wood: A Preliminary Hydrological Assessment. Sheffield Centre for Ecology and Environmental Management, Sheffield.

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Landscape, Water and History Ian D. Rotherham Sheffield Hallam University

London as Venice Introduction politicians are not responsible for the long-term In England and Wales around five million trends and circumstances that add up to people live in areas at risk from flooding, and disaster. A lack of critical and targeted yet we seem perpetually surprised when we get investment in some aspects of infrastructure, wet. However, take a map of the flood-risk and especially cuts in funds to key agencies, areas and overlay a map of the land wrested by might fairly be laid at their door, but even that drainage and ‘improvement’ from the once is only part of a longer-term neglect. Local great fenlands, and the two are virtually the politicians nationally are guilty of ‘development same. In the summer of 2007, first South at any price’ and ‘sod the flood plain’, but then Yorkshire and then the West Midlands they always have been. What’s new? experienced unprecedented damage and Discussions with politicians, media reporters disruption with catastrophic floods in June and and others suggest a reluctance to accept what July. At the time a lot of reporting and many happened as anything other than a one-off politicians stated that this was unusual and disaster, rather than part of a long-term trend. unexpected. I disagree. The floods were Yet by the autumn of 2007, and the winter of certainly extreme, and they were worse than 2008, the same areas affected by the summer most others of recent times, but history and floods were once again inundated. In January science tell us that these are both predictable 2008, Andrew Wood, spokesperson for Natural and they were predicted. What is more, a England, to the Defra select committee inquiry simple consideration of how we have managed into flooding, stated that, ‘managing water the landscape in recent times suggests that naturally reduces flooding’. Not only this, but these events should be expected; and with also that thriving wetlands, restored peat bogs global climate change this will be more so in and free-flowing rivers are recommended by the future. Yet time and again, we seem to be Natural England to reduce the harmful effects caught with our corporate trousers down, and of flooding. By increasing the natural capacity are terribly surprised. It is also very easy to find of the countryside to absorb and hold excess people to blame; and we live in an increasingly water, the risk of flooding could be blame-orientated society. Realistically today’s

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twentieth centuries. Research at Sheffield Hallam University showed how the floods in the year 2000 scoured out the sediments to release the toxins downstream. The hope is that that the sheer volume of water has diluted the impacts. However, this is not known for certain, but it is clear that very nasty chemicals have been re-released and have ended up somewhere downstream. Other problems are the sheer volume of flood-driven erosion carrying sediment down into the lower catchments. This may add to the damage caused as sediment- loaded waters hit the flood-risk zones. This isn’t new; prehistoric forest clearance caused Medieval flood in Somerset massive downwash of soil and sediment from, for example, the Pennines into the low-lying dramatically decreased. This is exactly what I, rivers such as the Trent, the Ouse, and even and others, notably Chris Baines, have been across the extensive Lincolnshire Fens. This advocating for over ten years. Today, Chris same erosion now causes catastrophic damage Baines and others are campaigning for an to heritage landscapes, in parts of Yorkshire extension to a ‘whole landscape approach’ and eroding important archaeological sites as more woodland In particular they see a need for swollen rivers rip through the landscape. more woodland on the hillside and a reduction Archaeology that has survived a thousand years in the numbers of grazing animals in critical can be lost in a few hours. upland areas. Long-term, grant-aided policies have subsidised over-grazing of many moors Another problem that seems to be and former bogs; leading to soil compaction overlooked is the spread of invasive, alien and reduced vegetation cover. Combined with species, particularly Japanese Knotweed, Giant publicly-funded drainage of the same Hogweed, and Himalayan Balsam, but also landscapes, the results have been short-term various aquatic invaders. There is much talk of boosts to productivity but totally unsustainable. ‘whole catchment approaches’ to management We are now paying the penalty. Water that falls of invasives, but in truth very little action. on such land runs off extremely quickly, Recent floods are now spreading propagule of potentially causing floods downstream. these species far and wide, so we can expect an exponential increase in the problem over the The solution may involve the undoing of next few years. They all thrive on disturbance, work of so-called ‘land improvement’ and the floods bring that with a vengeance, and undertaken over many decades. There are other the potential long-term costs will be enormous. issues too, and in particular the massive erosion of soil and sediments is worrying. This has an effect on the impacts of flood waters downstream. However, there is a hidden menace too with the re-working and major re- distribution of toxic chemicals from a century or so of heavy industry. In catchments like the Rother in North Derbyshire and South Yorkshire, once the second most polluted river in Western Europe, pollutants such as lead, zinc, cadmium, mercury and dioxins were laid down within beds of sediments; a legacy of the wealth-creating industries of the nineteenth and

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Example of the downstream migration of mercury An example of contaminant sources the distribution contaminant plume along the river Rother catchment of industrial sites along the River Rother in 1960 (courtesy of Frank Spode and Badria Ahmed) (courtesy of Frank Spode and Badria Ahmed)

Ever since the dawn of farming in the Fertile Crescent around Egypt, people have recognised the benefits of nutrients deposited as alluvium on the lower floodplains of their rivers. The flatlands of alluvial valleys and floodplains NOTE: The contamination plume identified by present easy and ideal lands for development as Murfin 1988, above Staveley, divides into two smaller long as water can be removed and then plumes at Hague and below Beighton, according to Duty (1995) constrained. This has always been the case, but increasingly so ever since the Industrial The present study indicates that the two smaller Revolution, and particularly during the latter plumes are migrating downstream, with upper one half of the twentieth century. Furthermore, around Renishaw and the lower one approaching valleys and valley bottoms have provided Catciffe from Beighton. routes for transport (roads, railways, canals) People and Water and other infrastructures (power-lines, pipelines, etc), again more so since the To a casual observer visiting Planet Earth, it Industrial Revolution and the development of might seem odd that people go to such great necessary engineering capability. In earlier lengths to place themselves, their families and times people often stuck to easier high ground their property on land so clearly at risk from and ‘ridge-ways’. The more modern approach inundation. This is an obvious point and one brings people and infrastructure directly into worth considering. The truth is that people love the forefront of potential flooding; at the same and need water – for drinking and food time removing or restricting the natural flood (especially fisheries), for transport and trade, management systems and compounding risks. It for reasons of defence, for agriculture, for is informative to consider the reasons behind industry. Furthermore, lands taken from water, the causation of floods, and Table 1 presents a coastal or riverine, are rich and productive. tentative assessment. Clearly many of the issues

140 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 and causes are inter-linked and it is difficult to Engineering a solution simply separate out specific factors for For both agriculture and urban or industrial particular floods. However, there are general development, the solution to water management trends that become obvious if floods are and to flood risk over the centuries, has been considered in this way, and if the historic through engineered structures. When these have context is recognised. failed or created other problems the answer has been more engineering. There are now consequences of this approach as first raised by Jeremy Purseglove in the 1980s in ‘Taming the Flood’ (1988). Quite clearly engineering is part of the solution; unfortunately it is also a part of the problem. Perhaps the biggest issue is not the actual impact of engineering, but the perception it has generated that we can simply engineer a solution, technology will prevail. Growing through the Industrial Revolution, and especially during the technological revolution since the 1950s, the assumption has been that 1947 Floods at Haddenham, Cambs nature is there to be tamed and controlled and that this can be achieved with the blunt Flooding, when it occurs, may be a regular instruments of heavy engineering. Whilst and to a degree predictable phenomenon or it technology and engineering have an important may be very sporadic and unpredictable in place, especially in the strategic protection of terms of location and timing. Some smaller important infrastructure, they are not by events are essentially localised, and others themselves a solution. The Victorian engineers occur over vast areas and often move spatially and agricultural improvers solved many and temporarily through a catchment. Floods problems, but their solutions now in part, taken can also be considered as topographic when to an extreme, have compounded the serious they occur to a large degree because of spatial environmental issues of the early twenty-first location, landform, and interrelationships. century. However, they can also be what I describe as It is worth considering a few examples of ‘topogenic’ where they arise through saturation urban developments over time and the of a perched aquifer or burst out of an consequences of people choosing to populate otherwise minor seepage line. These generally the river landscape. This just touches on what is relate to geology and topography on a localised potentially a huge subject. scale, or to superficial geology such as clay deposits, and are generally minor. However, they can be unexpected as their occurrence is away from recognised flood-risk areas, and so their impacts can be unexpected and, to a householder, distressing. When aquifer recharge has been affected by long periods of dry weather or by localized impacts of development, the potential for such a flood can be hidden. With long periods of wet weather as experienced in 2007, then these minor events can become a problem.

141 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 events are related to a) or c) ples include ‘North Sea Surges’ Surges’ Sea ‘North include ples events. Again Lynmouth 1952 would events. Again Lynmouth ild or cultivate floodplain or s such as throughout the 1970s - uth Yorkshire floods of 2007 were and the York 2000 floods. Potential problem when people bu when people problem Potential town and city floodMany smaller 1990s are associated with a). Many localised flood events are linked to a) and b) is often a 2. and 3, between distinction a clear is not There factor. compounding vary between but the balance may of c), as wouldbe an example Sheffield 1864. Oxford,The Gloucester, and So of 3 d). examples flood localised and more regional Many 2007, including the Summer 1953 East Coast floods related to b). Sheffield of 1864 related to d). Flood Great remove/reduce flood capacity. Exam remove/reduce and the Severn Estuary flood of 1607 These are often combined and contributing factors recent to many 1952. offloods. a)/b) would be Lynmouth An example or exaggerated by catchment or exaggerated by catchment rvoir dam wall collapse, bridges bridges wall collapse, dam rvoir Coastal inundation Coastal and affect impound that as bridges such modifications Channel Modified agricultural and forestry management Infrastructure located in ‘at risk’ locations rebound post-glacial worsened of settlements inundation Coastal Structural failures such as reservoir wall dam collapse worsened River floodplain event River floodplain event modified as Victorian such infrastructure under-performing or Failing as Victorian such infrastructure under-performing or Failing Storm eventsStorm flats and of saltmarsh, by removal Coastal inundation worsened Structural failures such as rese by wider worsened of settlements floodplain inundation River

a) c) a) water-flow c) zone in coastal of settlements and development sand dunes a) c) b) storm and by intensified sea-level, by rising and sinking coastlines, events events storm and by intensified modification landscape d) events storm and by intensified modification landscape by wider b) channel drainage, catchment as upper such modifications catchment and lower of mid and urbanisation straightening, b) town drainage b) collapse and sudden drainage to blockage causing d) a) landscape wider to due water by increased now hit drainage town modification c) Category Examples Comment Table 1. BASIC NATURE FLOODING AND CAUSATION OF phenomenon 1. Natural generated 3. Human phenomenon generated 4. Human phenomenon exacerbated by environmental factors 2. Natural phenomenon phenomenon 2. Natural exacerbated by human actions

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Settlements and water 1. Nottingham

1830s 1900

1920s

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2000 © Crown Copyright Ordnance Survey. A joint EDINA/DIGIMAP project.

Note the massive urbanisation, the huge impact of transport and other infrastructure, and the major incursions onto the River Trent floodplain. The porosity and permeability of the landscape is transformed, but critically, the ability to store or hold back floodwaters is catastrophically reduced.

2. Chelmsford

Rivers Chelmer and Blackwater catchment c.1920

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The main thing to note here is the extensive floodlands areas ‘liable to flooding’ in the early 1920s, and that since then the entire region has become urbanised with major incursions into the flood-risk zone. Catchment behaviour will have been transformed by the urbanisation process, water absorption having decreased and the speed of water drainage increased. Charleston, South Carolina, late 1800s The North American Experience Recent events in the Southern States of the USA exemplify many of these issues and on a massive scale. The North American landscape was largely unaffected by engineering, by urbanisation, or by agricultural and forestry ‘improvements’ until the 1700s, and increasingly from the 1800s. Again a superficial view of impacts through topographic maps illustrates the scale of the effects. The locations of most major urban developments are coastal, South Rocky Mountain Land Co, North valley-bottom floodplains, or river deltas. Many Carolina, late 1800s cities such as New Orleans have histories of These examples illustrate the European catastrophic flooding since their inception. In process in taming the landscape, but telescoped parallel to their rapid urban development there into less than two centuries. The scale of has been speedy and often total transformation development and landscape modification is of the landscape in which they are seated. immense, and the impact on water and on flood risk enormous. People and property are placed at the critical points of environmental risk, and the latter is magnified through wider landscape impacts.

Pensacola, Florida, late1800s

Tallahassee, Florida, 1920s

Birmingham, Alabama, early 1900s

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Lessons of History context of storm surges and their frequency History, both recent and further back in time, over a 900-year period. Writing in 1978 about tells us that flooding is not a new phenomenon. The East Coast Floods, Dorothy Summers Accounts ever since the Bible have told stories raised exactly these issues; firstly that the of floods and of terrible storms. It seems terrible floods of 1953 were not exceptional, strange, therefore, to view recent events as but a part of a long-term trend. Secondly, she somehow unusual or unexpected; extreme yes, notes that the actual devastation caused in 1953 but unexpected, no. There have even been was so much worse largely because of the major tsunamis in Britain, with a massive series numbers of people that had moved in to live in of tidal waves striking eastern Scotland around the areas at risk. Thirdly, she challenges the 7,000 years ago, and then one around the ideas of storm event return periods that may Severn Estuary in the 1700s. There have always give a false sense of security and comfort to been storms and tempest, and people have planners, politicians, and to those at risk. And always suffered. Indeed, not only have floods finally she draws attention to the inability of and flood risk always been with us, but our specialists to predict the conditions that will management and use of the landscape, now lead to the next devastation. So, whilst dealing combined with climate change, make them with an event that took place over fifty years more rather than less likely. Some of this is ago, much is transferable and many lessons are actually very hard to prove beyond doubt in a yet to be learned. Again, a brief historic survey scientifically testable way. However, reveals the same location being affected time observation of trends, a triangulation of and again. Holmfirth, for example, suffered findings, and plain commonsense, leave little severe floods in 1738 and 1777, and then in doubt as to what is happening. There is a 1852 the famous ‘Holmfirth Flood’ when degree of denial in certain quarters. So when Bilberry Reservoir burst its dam and eighty-one Chris Baines and I put proposals to Sheffield lives were lost. But floods struck again in 1944 City Council planners in the early 2000s, to with further loss of life and extensive damage assess the catchment and look at positive water to property. The 1854 flood followed heavy management opportunities, we were told rain but it was linked to reported construction ‘Sheffield will never flood again’. Basically defects in the reservoir. The torrent of waves their major engineering works undertaken in crashed through Holmfirth and on as far as the 1980s and 1990s would deal with any Lockwood, near Huddersfield. York is regularly eventuality. When questioned about wider inundated, but over the decades so have Derby, catchment issues or the need to alleviate flood Oxford, Malton, Nottingham, Norwich, and risk downstream the response was ‘not our many others. problem’. Despite support on offer from both It is always suggested that each flood results Yorkshire Water and the Environment Agency, from unprecedented and unusual weather, a the proposal never even got past senior case of an ‘extreme event’; so how many planners to politicians. unusual and infrequent events must we Yet even a cursory dip into history and a experience before they are accepted as sifting through newspapers over the last 200 increasingly the norm? In Yorkshire, for years produces a vast array of examples of example, we had floods in York and Thirsk in flood and storm catastrophes. Whilst coastal November 2000, Helmsley in June 2005, Leeds flooding has different causes and raises other and Harrogate in September 2006, and South issues, some of the context is the same. Yorkshire and Ryedale in July 2007. This Furthermore, in some east coast zones and suggests these are not so unusual. They are especially around the Thames, inland and extreme, but with climate change extreme coastal flooding could easily combine to becomes commonplace. Climate manifested in devastating effect. Dorothy Summers assessed the weather is changing; getting more extreme, the 1953 east coast flood and set this in the both hot and dry, or as we witnessed in 2007,

146 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 torrential deluges of rain. The autumn of 2000 the flatlands of Doncaster, the Severn Valley, was the wettest for 270 years; the associated and the Cambridgeshire Fens, the story is the flooding affected 10,000 properties. In January same: drain, drain and drain. 2005 there were floods affecting around 3,000 properties, with a similar figure for June and Farmers have been driven by government July 2007. With global climate change now an polices over decades, by massive subsidies accepted fact, although we can debate the exact from EU and UK governments, and by public causes, it has been calculated that the demand for evermore cheap food. However, associated costs of flood damage might be £25 there is now a cost. This probably peaked in the billion per year, an increase from the present £1 1970s at around 100,000 hectares drained per billion. These are the raw figures that disguise year. Whilst the trend has largely halted, any even greater worries and costs. reversion has been very piecemeal and relatively modest. With our rivers straightened Landscape Change and canalised, they are now locked into artificial banks, and the natural drainage There are other factors too, and in particular the systems are de-coupled from their floodplains. way people have changed the landscape over The latter are massively reduced or totally the centuries. So over hundreds of years, but removed. Rivers are mostly lined by intensive increasingly during the late twentieth century, farming which grew rapidly from the 1950s to we have changed the environment in which we the 1990s. This was especially the case in live, work, and recreate. Urban areas have flood-risk areas such as throughout the Severn, sprawled out over floodplains, turning soft, the Vale of York, the Rother Valley, the Don porous surfaces to tarmac and concrete. But Valley, and similar landscapes throughout there is more. Our impacts haven’t been Britain. In other areas, localised but significant, restricted to the built environment; we have the riverbank has been sacrificed to urban city drained and ‘improved’ huge areas of farmland. heartlands and industry. If this wasn’t enough, Drainage was an obsession of the Victorians. in recent years we began to build anew on From the highest parts of the Pennines, the former expansive floodplains, the natural North York Moors, and mid Wales with their control systems of Britain’s lowland ‘gripping’, to the lowlands of the Vale of York,

Agricultural drainage at macro- and micro-scales

147 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 landscapes. We have also removed woods and impact on the water-holding capacity of this trees from the landscape over many centuries; catchment. In water supply terms, this has been and many wooded or plantation sites today are calculated as equivalent to the loss of a also extensively drained. This is analogous to reservoir containing 340 billion litres (or 75 the grips of upland moors, but is almost totally billion gallons). The water storage capacity of overlooked. Anyone involved in Forestry peat is prodigious. For example, ombrotrophic Commission schemes from the 1950s to the Sphagnum-peat can hold 500-600% water on a 1990s will tell you about the extent and scale of dry weight basis (Cressner et al., 1997), whilst drainage involved. All this removes capacity to peat on average contains 5.5 gallons per cubic hold water and to slow its movement through foot (Baird et al., 1997). The catchment is the landscape. illustrated below to show the macro-linkage between upper and lower catchments. These are joined by landscapes of urban development and often of industry or intensive agriculture. Over around three centuries this landscape has been transformed from being dominated by heath, moor, woodland, unimproved pasture, marsh and fen, from the high ground to the coastal lowlands. There is also confusion in the scientific literature and in the popular media that can lead to potentially serious misunderstanding of the Victorian draining competition processes. So for example, it is often suggested by hydrologists that a saturated raised mire The South Yorkshire Case-study (peat bog) sheds precipitation (rain) from its England’s third largest fenland, bordering North surface rather than allowing it to be absorbed Lincolnshire, Nottinghamshire, and South by the ground beneath. It thus acts as Yorkshire, was almost totally destroyed by the effectively as say an artificial surface like early 1900s by the long-term impact of concrete in generating rapid run-off. In such a intensive land management and the drainage case, it is argued that a cut-over, drained or efforts of the Dutch engineers. The removed peat surface will benefit the water consequences and impacts of these changes are management and water-holding capacity of a discussed by Rotherham & Harrison (2006). In catchment. It is further suggested that the South Yorkshire, before the drainage of 36,420 massive removal of peat that our research has hectares of the Humberhead Levels the area documented in the South Pennines, therefore was ‘…A continual lake and a rondezvous of ye has little or no negative impact on the waters of ye rivers….’ (De La Pryme, 1699). hydrological behaviour of the catchment. The However, this is only the lower part of the argument derives from the repeated findings of catchment. In the upper zone, the high Pennine two or three research papers in the 1960s on the moors, there has been massive peat fuel hydrological functioning of raised mires; and removal and associated drainage. This has been the research is sound. However, the context has followed by intensive farming of sheep and been totally misunderstood at the landscape grouse with associated gripping. The ‘Dark scale, and this leads to an entirely misleading Peak’, from which a massive amount of peat conclusion. At a landscape scale, in order to has been removed, is surrounded by valleys drain or remove a raised mire unit, it is now famous for their water-supply reservoirs. necessary to drain and severely modify the The removal of peat, conservatively estimated entire landscape in which it sits. The resulting as around 34 million cubic metres from the desiccated moorland or grassland has a Dark Peak plateaux, undoubtedly has a major massively diminished water-holding capacity

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The South Yorkshire catchment and during storm events holds little water back. Coastal zones pose particular problems with The network of drains, ditches and grips, in regard to storms, floods, and erosion. In general many cases, dates back to the 1800s, and in they are exposed to major storm or tidal some places is present by, at the latest, 1600. impacts, and obviously extremely vulnerable to The peat mass has shrunk beyond recognition, sea level rise. In Britain there is the particular often retracted distances of many tens of miles. problem of coastal subsidence and erosion, and But there is more. These once extensive peat hence exacerbated flood risk. However, a major bogs were historically linked across the wider reason for the concern about coastal areas is landscape to heaths, commons, woods, fens and simply because we have reclaimed large areas marshes, from the high Pennines to the East of productive land from the sea, but they may Coast. This is the landscape that has been no longer be sustainable. The other main removed by enclosure and ‘improvement’, and anthropogenic factor is the urbanisation of more recently by industrialisation, agri- coastal zones, much associated with the industry, industrial forestry, and creeping Victorian seaside holiday resort. Imposed on urbanisation. often exposed and vulnerable coastlines, they contract with the more pragmatic locations of The urban landscape is now permeated by older fishing villages and ports. Central to the networks of drains for services and utilities, imposition of development is the concept of with beds of aggregate drawing water quickly ‘fossilisation’ of an inherently dynamic through the under ground surfaces. environment, and the control of hostile Impermeable ‘hard’ surfaces dominate and elements; and in most cases this has been water pours off into canalised and often successful. culverted water-courses. However, whilst much of this is obvious even to the casual observer, The Role of Today’s Landscape the drainage of the ‘green’ environment is less Managers demonstrable. But read any account of land management and agricultural ‘improvement’ There is a need to respond at all levels from from the 1700s to the 1900s, and there is an very small to massive, with sometimes a gentle obsessive theme – drain, drain, drain. approach to water management. For those who manage landscapes, from conservation managers to farmers, to foresters and arboriculturists, there are other complications in

149 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 terms of landscape change. In our twenty-first they may recall that not so long ago, Yorkshire century landscape for example, almost all was gripped by horrendous droughts. Recent valley-bottom riverine woodlands have been floods don’t make future droughts less likely, removed. Lowland floodplains have been but are part and parcel of the same long-term simplified, rivers straightened and the trees problem. Similarly, travelling around the world removed or, at the very best, reduced to ribbons you witness extreme and long-enduring of riverside trees. In times of flood there is droughts, coupled with dramatic storms and nowhere left for the water to go. Ironically the flood events. What we see in Britain is part of remaining riverside trees are now targeted as this bigger global picture. villains of the peace that may exacerbate flood damage. Many are now scheduled for removal. There is a problem, too, with the calculation But we also need to look inside the woods as of flood ‘return periods’ based on historic data. well as at the woods in the landscape. There is Issues with these are well-known, and though tremendous potential to target woodlands and the basic calculation is valuable and to an plantations with localised blocking of extensive extent informative, there are problems. The drainage networks. This would serve to limitations and the difficulties inherent in moderate extreme effects of summer droughts forecasting the likelihood of a severe event are on trees and on woodland ground flora, and problematic and are rarely understood by media importantly it would maximise water retention reporters or by the public whose houses may be in times of flood. Organisations such as the at risk. Changed landscape as a context, National Trust are now re-planting gill-sides on changing climatic conditions (now and in the their north Pennine estates, in order to slow the past), and the rarity of extreme events, combine run-off of water; a small step, but in the right to make return period calculation a useful direction. However, this still needs to run exercise of questionable reliability. deeper. There are large areas, such as the So where do the 2007 floods leave us? We Longshaw Estate in Derbyshire for example, must seek answers, and try to understand what where extensive drainage networks still is happening; together with why, and what we desiccate swathes of woodland, grassland and can and must do. This is not easy, and it is moor. Local authorities such as Sheffield City important to realise too, that the ‘rules of Council, own large numbers of woods, and engagement’ between people and nature are almost all have extensive drainage networks changing, and fast. To add to the problems, our than could help hold back flood waters. increasingly extreme weather is dumping unbelievable quantities of water on to Conclusions: Learning from the vulnerable areas, and in short, intensive Floods periods. However, it is important to recognise It is important now to learn key lessons from that these are not entirely new; extreme events these events, and to respond quickly and have happened before and not uncommonly. As effectively. But what we learn and how we we experienced this summer, though, the heavy prevent flood damage on this scale reoccurring, rain is coming in the midst of longer, persistent or at least limit the damage, is in itself a rainy periods. Consequently the ‘natural’ challenge. It is very likely now, if not certain, landscape cannot cope, and the built structures that with global climate change these so-called are at their limits or beyond. With what we’ve extreme events will get worse and more done, this is hardly surprising. The emerging frequent. So the bad news is that this is just the policies of Natural England recognise this beginning. It is often overlooked, but wider landscape function – dismissed by water fundamental to understanding the nature of the engineers and planners for a very long time. problem, to realise that drought and flood are They now speak of a ‘flood-friendly’ landscape flip-sides of the same issue. Readers will be that is managed to minimise risk. Importantly aware of the extreme droughts that have for landscape managers, this will include trees plagued south-east England in recent years, and and woods, and marshes, ponds and bogs, and

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Meade, R. and Hume, P.D. (Eds.) British Ecological Society, London, and the Macaulay Land Use Research Institute, Aberdeen, UK.128-139. Brown, W.R. & Cutchen, B.W. (1975) Historical Catastrophes: Floods. Addison- Wesley, Reading Massachusetts. Butler, D. & Davies, J.W. (2000) Urban Drainage. E. & F.N. Spon, London. Bye, P. & Horner, M. (1998) Easter 1998 Bentley, Doncaster, 1932 Floods. Volume 1. Report by the Independent Review Team to the Board of the Environment wetter grasslands and heaths, complements to Agency. Environment Agency. ISBN 1-873- existing and new engineered flood defence 16066-6. structures. Clark, C. (1983) Planet Earth Flood. Time-Life Bibliography Books, Amsterdam. Anon.1 (1998) Easter 1998 Floods. Volume 2. Cressner, M., Yesmin, L., Gammack, S., Report by the Independent Review Team to the Dawod, A.K., Billett, M., & Sanger, L. (1997) Board of the Environment Agency. The physical and chemical ‘stability’ of Environment Agency. ISBN 1-873-16067-4. ombrogenous mires in response to changes in precipitation chemistry. In: Blanket Mire Anon.2 (2001) Learning to live with rivers. The Degradation : Causes, Consequences and Institution of Civil Engineers, London. Challenges. Tallis, J.H., Meade, R. and Hume, Anon.3 (2002) The Water Framework Directive. P.D. (Eds.). British Ecological Society, London, Guiding principles on the technical and the Macaulay Land Use Research Institute, requirements. Environment Agency Bristol. Aberdeen, UK. 153-160.

Anon.4 (2005) Planning for the Rising Tides. De La Pryme, A. (1639) Letters as quoted in The Humber Flood Risk Management Strategy. Dinnin (1997) in Van de Noort, R. and Ellis, S. Consultation Document August 2005. (1997) Wetland Heritage of the Humberhead Environment Agency, Hull. Levels: An Archaeological Survey. Humber Wetlands project, University of Hull, Hull. Anon.5 (2001) Sustainability – Development and Flood Risk. Proceedings of the CIWEM Doe, R. (2006) Extreme Floods. A History in a National Conference 2001, CIWEM, London. Changing Climate. Sutton Publishing, Stroud, Gloucestershire. Ardron, P.A., Rotherham, I.D. & Gilbert, O.L. (1996) Peat-cutting and upland landscapes : Eddison, J. (1979) The World of the Changing case studies from the South Pennines. In: Coastline. Faber and Faber Ltd, London. Landscape-Perception, Recognition and Girling, R. (2007) Sea Change. Britain’s Management: reconciling the impossible? Coastal Catastrophe. Transworld Publishers, Proceedings of the Landscape Conservation London. Forum Conference, 2-4 April, 1996, Sheffield. Landscape Archaeology and Ecology, 3, 65-69. Harlow, I. (2004) Holmfirth floods. The Story of the Floods in Holmfirth. ALD Design & Print, Baird, A., Beckwith, C. & Heathwaite, L. Sheffield. (1997) Water movement in undamaged blanket peats. In: Blanket Mire Degradation: Causes, Consequences and Challenges. Tallis, J.H.,

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Law, F.M., Farquharson, F., Brampton, A., Challenges. Proceedings of the British Dale, M. & Flather, R. (2003) Environmental Ecological Society Conference in Manchester, change indicators (including those related to 1997. British Ecological Society and the climate change) relevant to flood management Macaulay Land Use Research Institute, and coastal defence. R&D Technical report Aberdeen. 38-41. FD2311 April 2003. Defra – flood Management Division, London. Smith, E.J. (1947) Black Winter. The story of the storms and floods of 1946-1947 and of the O’Connell, E., Ewen, J., & Quinn, P. (2007) Is devastation on the land which followed. there a link between agricultural land-use Published by the Farmers Weekly and Hulton management and flooding? Hydrol. Earth Syst. Press Ltd, London. Sci., 11(1), 96-107. Summers, D. (1978) The East Coast Floods. Pearce, F. (2006) When the Rivers Run Dry. David & Charles, Newton Abbot. Beacon Press, Boston Massachusetts. Tidwell, M. (2006) The Ravaging Tide. Strange Pollard, S. & Guy, J. (Eds.) (2001) Risk Weather, Future Katrina, and the Coming Assessment for Environmental Professionals. Death of America’s Coastal Cities. Free Press, CIWEM, London. New York. Purseglove, J. (1988) Taming the Flood. Oxford Withington, J. (2005) A Disastrous History of University Press, Oxford. Britain. Chronicles of War, Riot, Plague and Flood. Sutton Publishing, Stroud, Robinson, D.N. (2000) The Louth Flood. The Gloucestershire. story of the events of Saturday 29th May 1920. Louth Naturalists’, Antiquarian and Literary Wood, L. (2002) The Great Borders Flood of Society, Louth. 1948. Tempus Publishing Ltd., Stroud, Gloucestershire. Rotherham, I.D. & Harrison, K. (2007) A memory re-discovered of South Yorkshire’s fens: map-based reconstruction of the region’s former wetlands. The Yorkshire Naturalists’ Union Bulletin, 48, 1-8. Rotherham, I.D. & Harrison, K. (2006) History and ecology in the reconstruction of the South Yorkshire fens: past, present and future. Proceedings of the IALE Conference, Water and the Landscape: The Landscape Ecology of Freshwater Ecosystems, 8-16. Rotherham, I.D., Egan, D. & Ardron, P.A. (2004) Fuel economy and the uplands: the effects of peat and turf utilisation on upland landscapes. Society for Landscape Studies Supplementary Series, 2, 99-109. Rotherham, I.D., Ardron, P.A., and Gilbert, O.L. (1997) Factors determining contemporary upland landscapes - a re-evaluation of the importance of peat-cutting and associated drainage, and the implications for mire restoration and remediation. In: Blanket Mire Degradation. Causes, Consequences and

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Woodland Actions for Biodiversity and Their Role in Water Management I.R. Calder1, J. Harrison1, T.R. Nisbet2, and R.J. Smithers3 1. Centre for Land Use and Water Resources Research, Newcastle University; 2. Forest Research 3. Woodland Trust

Introduction Projected impacts of climate change are taken The highly fragmented semi-natural habitats of into account. the UK are vulnerable to climate change. There The report considers the implications for water is a need to develop landscapes that are resources at a catchment scale, regionally and resilient, i.e. able to absorb and respond to nationally in the UK, of: changes, thereby sustaining biodiversity and ecosystem goods and services. Woodland • maintaining the existing area of native and actions for biodiversity have an important role ancient woodland to play ecologically and may have considerable • restoring non-native conifer plantations on potential to contribute to economic and other ancient woodland sites to native woodland benefits. • converting other non-native conifer Increasing attention is being given to the plantations to native woodland interactions between woodland and water, as • planting/regenerating native woodland on integrated land and water resource management arable land, improved pasture and within seeks to address a number of water issues, urban areas, including riparian, wet and including the threats posed by climate change. floodplain woodland While a wide range of projects have researched • restoration of semi-natural open-ground or reviewed particular aspects of water habitats from conifer plantations management on which trees and woodland have an impact, there is a need for an accessible Relevant ongoing research is identified, as are overarching synthesis. This paper is an knowledge gaps and research priorities yet to abridged version of a report published by the be addressed. Woodland Trust. The literature review Aims A comprehensive bibliography is cited but the The report reviews national and international literature review is not included here and can peer-reviewed and ‘grey’ literature on the be found in the report published by the positive and negative, direct and indirect, Woodland Trust. Key caveats to the literature impacts of trees and woodland in temperate review and its application to the UK are systems on water resources in relation to: explained below. • water quality: turbidity/siltation and Native woodland and forestry in the UK riverbank stability; eutrophication; pesticides and other chemicals; acidification; water A distinction is made between conifer forest colour/dissolved organic carbon and broadleaved woodland in the UK, and between UK forestry and forest management • water quantity: streamflow; groundwater elsewhere in the temperate zone. Most conifer recharge; soil infiltration and run-off forests in the UK have been planted in the last pathways; base or low flows; peak flows; ninety years as monocultures for commercial flood frequency, intensity and risk. timber production. Concentrated in the uplands,

153 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 the wettest parts of the UK, sites for conifer Scale planting have been cultivated and, crucially, Empirical evidence of the impacts on water drained to ensure establishment. Silviculture resources of trees and woodland comes from can involve frequent thinning on more stable studies of individual trees, stands and localised sites, and often clearfelling. These intensive research. Extrapolating findings is complicated forestry operations have the potential to have a by a range of variables as scale increases. high impact, although this is increasingly Within individual sites, diversity of woodland controlled by improved forest design and best structure and tree species tend to increase with management practices. By contrast broadleaved area, as does the proportion of open habitats, woodland in the UK has generally been around roads and tracks. Moving to a larger catchment longer and is predominantly lowland. scale or beyond, land use patterns and Broadleaved woodland is rarely drained and management practices become ever more silvicultural systems are generally low impact. complex, as do variations in topography, Elsewhere in the world, temperate forestry is geology, soils, rainfall, snowmelt and run-off focused on a long-established forest resource pathways, woodland type, age and growth rates. and, unlike in the UK, is more often based on This limits understanding of interactions selective harvesting and regeneration rather between land use and land-management than afforestation and clearfell. It is important practices on water at the river-basin scale. to understand this distinction in drawing conclusions from studies across temperate As the percentage of woodland cover zones and applying their findings to the UK. declines, its signature is diluted by other land uses. Similarly, it may be difficult to identify Quantification impacts on water against natural background The impact of native woodland on water variation when less than 20 per cent of a resources is affected by many factors and there catchment is subject to woodland creation or has been limited quantification in the UK. removal. Smaller-scale woodland creation may Overseas research needs interpreting with nevertheless have a discernible impact on both caution due to differences in climatic flood flows and water quality at a local level, if conditions, soil types and woodland species it is appropriately targeted (e.g. within riparian (e.g. many studies consider mixed conifer and zones). This is particularly relevant, as the UK broadleaved stands). The majority of historic has less than 12 per cent woodland cover. catchment studies on forest hydrology have been conducted in the USA. No studies have Seasonality measured the effect on streamflow and water Seasonality is a significant factor affecting yield of changing land use from short water use and its impact on water resources. vegetation to mature broadleaf woodland due to Transpiration loss from grass starts earlier in the timescale involved. Research has focused the year than broadleaved woodland; however, on the impact of woodland clearance on drought can lead to early ageing of grass and catchment water yield. Impacts of woodland shorten the growing season. This can influence clearance cannot simply be used to infer seasonal flows, although timing depends on the changing water yield for new woodland as it amount of water stored in underlying soils and matures. This is because of: the lack of a rock and the lag in drainage waters reaching suitable control (comparison only possible with rivers. clearfelled site); the partial nature of felling treatments, in many instances; and the potential for harvesting to complicate results, due to levels of disturbance.

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Policy context The main evidence of an effect of climate change on water quality is the widespread Impacts of climate change on woodland and rising trend in dissolved organic carbon water concentrations in many upland streams across Climate change projections for the UK are the UK and Europe. Thought to result from generally for warmer, wetter winters and hotter increased mineralisation of soil organic matter drier summers with more prolonged droughts, due to climate warming, dissolved organic particularly in the south, and evaporation totals carbon concentrations, and associated water increasing in all regions. The potential impacts colour, tend to be marginally greater in conifer on water resources and flood control are forest streams but is unlikely to be affected by significant and are expected to become more broadleaved woodland. Climate change may challenging in the future. Water supplies are also affect water quality indirectly by already severely stretched in some parts of the stimulating land use changes that bring diffuse UK, particularly the south, while at the same pollution to new areas. This might be reduced time growing pressure for housing development by targeting woodland creation to source areas, on floodplains and rising property values are pollutant pathways and as a buffer to riparian increasing the flood hazard. Impacts on water zones. Planting riparian woodland would have quality could also be significant with less water the additional advantage of providing shade to to dilute pollutants. Rising temperatures will help moderate the impact of rising water increase thermal stress for freshwater life. temperatures on sensitive freshwater life, especially salmonid fish. Implications for woodland and water in the UK Climate change is likely to have a significant Projected changes in climate are expected bearing on future planting and management of generally to lead to increased evaporation and native woodland. The Climate Change reduced water yields from both woodland and Programme and Energy Reviews that are non-woodland areas. Warmer temperatures underway may help to clarify woodland’s role increase potential evaporation rates and in mitigation and adaptation. There is lengthen the growing season and higher significant scope for harvesting of more atmospheric carbon-dioxide levels could biomass from native broadleaved woodland. enlarge total leaf area. Ultimately, if potential evaporation rates far exceed rainfall inputs, EU Water Framework Directive water use by all vegetation-types will converge. Woodland could play an important role in Nevertheless in water-scarce areas, for the helping meet objectives of the EU Water foreseeable future, large-scale woodland Framework Directive, including: to protect and creation may need to be restricted and species improve the status of Europe’s rivers, lakes, with a high water demand, possibly avoided. groundwaters, estuaries and coastal waters; to Most climate change scenarios lead to promote the sustainable use of water resources; projected increases in flood magnitude, and to help reduce effects of flooding and although its significance and timing is less drought. certain. The presence of woodland could serve A key target of the EU Water Framework as a buffer against excessive run-off and reduce Directive is for rivers to achieve good annual peak flows (e.g. in the West Weald, ecological and chemical status by 2015. This is West Sussex) but this may only be significant a major challenge, with 93 per cent of rivers in in relatively small catchments where woodland England and Wales at risk of failing to achieve is predominant. Targeted floodplain woodland it (Figure 1). The two most important threats creation could alleviate flood risk. are diffuse pollution and physical changes, often associated with agriculture and urban development. The main sources of diffuse pollution responsible for at-risk water bodies

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Figure 1. Percentage of water bodies in England and Wales at risk of not achieving EU Water Framework Directive objectives. are: sediment delivery (21 per cent), pesticides taken into account when the original UK targets (21 per cent), phosphorus (47 per cent) and were set. The targets were reviewed in 2005–6 nitrate (38 per cent). Some 48 per cent of rivers and are designed to improve the long-term are also at risk from physical degradation of viability of habitats and species populations. river channels and banks. The following targets have been set that relate to woodland: New native woodland creation has potential to reduce pressures by protecting soils and • Maintain the extent of native woodland in riverbanks, reducing rapid surface run-off and the UK (no net loss of one million hectares) intercepting pollutants before they reach • Maintain the current extent and distribution watercourses. Although this is scale-dependent, of ancient semi-natural woodland, which benefits could be maximised by targeting high qualifies as native woodland in the UK (no risk soils and careful placement of woodland to change in the existing area of 403,000ha intercept pollutant pathways. This would • Restore 50,300ha of non-native plantations require better integration of farming and on ancient woodland sites to native woodland within catchments. River-basin woodland in the UK by 2015 management planning is a key mechanism • Expand the current native woodland resource within the EU Water Framework Directive for in the UK by 134,500ha by 2015 through a delivering improvements to the water combination of converting (restocking) environment. existing plantations not on ancient woodland If due care is taken, native woodland has sites and creating native woodland on former significant potential to sustain water quality and agricultural land alleviate flooding through its effects on run-off • Expand semi-natural open-ground habitats pathways and flood flows, without posing (which will include restoration where additional problems for water resources and planted with non-native conifers), e.g. droughts. The Environment Agency in England lowland heathland by 7,600ha by 2015. and Wales has developed Catchment Abstraction Management Strategies and Catchment Flood Management Plans for Likely implications for water catchments identified at risk from low flows resources of woodland actions for and flooding, and for groundwater bodies at biodiversity risk of not meeting good quantitative status. Based on the review of impacts of trees and forests on water resources, likely implications UK Biodiversity Action Plan for water resources of woodland actions for The UK Biodiversity Action Plan sets targets biodiversity in the UK are outlined below. for priority species and habitats to guide conservation action. Climate change is now recognised as a significant factor that was not

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Maintaining the existing area of native and Restoring non-native conifer plantations on ancient woodland ancient woodland sites to native woodland The main impacts on water resources can be This would benefit both water quantity and summarised as: quality, except where restoration is to native conifer woodland. Main impacts might be: • Preservation of high quality drainage waters with low nutrient, pesticide and sediment • Increase in water yield, and probably base concentrations due to lack of soil flows (by 20–50 per cent in dry regions and disturbance up to 10 per cent in wet parts of UK), • Maintenance of good or high ecological unlikely to be noticed at the level of a large status of water bodies draining catchments surface or groundwater body but could be dominated by native woodland, except locally significant, although slow to develop possibly for Scots pine within acid sensitive if restoration is gradual areas • Increase in small (less than one in every five • Reduction in water use and increased water years) floods (less than 10 per cent) due to yield as younger woodland matures lower water use and greater run-off from • Maintenance of water yield, and probably broadleaved woodland, especially during base flows, across large parts of central and winter and early spring when floods are southern England overlying chalk or clay most frequent soils (likely to be within plus or minus 10 • No effect on extreme floods per cent of that from grassland) • Reduction in threats to water quality • Reduction in water yield, and probably base following restoration, although these would flows, in dry parts of England (less than have been greatly constrained by the Forests 750mm annual rainfall) overlying sandy & Water Guidelines soils (likely to be 20–50 per cent less than • Reduction in streamwater acidification in from grassland) acid-sensitive areas due to the relative • Reduction in water yield in wet parts of the reduction in pollutant scavenging UK (greater than 1,500mm annual rainfall) • Sizeable reduction (up to 90 per cent) in (up to 10 per cent less than grassland) nitrate concentrations in very dry regions • Reduction in small (less than one in every (less than 600mm annual rainfall); five years) floods (10–20 per cent less than elsewhere, little change. grassland). Converting other non-native conifer Effects on water yield may be reduced with plantations to native woodland increasing size of woodland, as structural and The effects of converting plantations more species diversity grows and edge effects have generally are expected to be similar to those proportionally less significance. It is unlikely outlined immediately above. Once again, that small differences in water use expected changes to both water quantity and quality are between different native broadleaved tree unlikely to be significant where conifer species could ever justify species management plantations are converted to native pinewoods. to limit impacts on water quantity. Conversion Anticipated additional impacts are: of native pinewoods to birch could yield significantly more water but within its native • Increase in water quantity, returning it close range there is no demand. to that of the original land cover • Increase in flood retention where conifer plantations on floodplains are converted to native woodland, as hydraulic roughness would be increased by development of a shrub layer, ground cover and increasing

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levels of deadwood. Ancient woodland on soil infiltration, increase soil organic matter ground liable to flooding is rare, as it was levels, reduce drainage volumes and protect historically the most valuable land as soil from disturbance (taking care to avoid meadow, but conifer plantations on sites mobilising some pollutants through soil without a long history of woodland cover acidification) occur on floodplains. • Shade provided by new riparian woodland moderating the impact of rising water Throughout the UK, consideration is being temperatures on sensitive freshwater life, given to continuous cover forestry as a means especially salmonid fish of managing large areas of conifer plantations. • Reduction in surface run-off and This silviculture creates a certain degree of groundwater recharge where woodland shrub cover and age diversity in the crop but created on arable and brownfield land, as evidence would suggest limited benefits for woodland generally uses more water, unless water yield or quality. the arable relies on irrigation. Lighter- foliaged trees, such as ash, would limit the Planting/regenerating native woodland on difference, although reduction would still be arable land, improved pasture and urban expected on drought-prone soils and in areas wetter areas. Planting on grassland would Available evidence suggests native woodland also reduce surface run-off and groundwater creation on more intensively managed land will recharge, except on chalk or clay soils in benefit water quality status but may pose issues areas of intermediate rainfall where they for water resources. Impacts are expected to be: could be marginally increased • Improvement in water quality, as it removes • Little change to water yield, and probably the need for regular soil base flows, where woodland created on disturbance/cultivation and fertiliser and grassland across large parts of central and pesticide treatments and especially where it southern England overlying chalk or clay replaces potentially damaging land uses on soils (likely to be within plus or minus 10 sensitive soils (e.g. improved grassland and per cent) arable overlying soils prone to erosion and • Reduction in water yield, and probably base nutrient loss) flows, in dry parts of England (less than • Reduction in sediment, nitrate, phosphate 750mm annual rainfall) overlying sandy and pesticide concentrations (by as much as soils (likely to be 20–50 per cent less than 90 per cent possible) by aiding soil grassland) infiltration, retaining suspended particles, • Reduction in water yield where native binding nutrients and pesticides and pinewoods or yew woodland created, promoting nutrient removal via tree uptake regardless of existing land cover • Reduction in nitrate concentration linked to • No significant effect on water yield, base or scale of planting and significant decrease in peak flows where scale of planting is less sediment, phosphate and pesticide levels than 20 per cent of surface or groundwater achieved by small-scale targeted planting of body source areas and pollutant pathways, where • Reduction in small (less than one in every surface run-off emerges or seepage occurs five years) floods (10–20 per cent), as a close to the surface (e.g. downslope result of improved soil infiltration reducing boundaries of steep fields, springs, purpose- local peak flows (where water resources are built infiltration basins/swales, riparian not in short supply, selection of species with zones and associated wetlands) higher water use, such as poplar and willow, • Retention of chemical pollutants on could further aid attenuation of summer brownfield sites, through use of trees in floods) sustainable urban drainage systems to aid

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• Possible reduction in extreme floods • Effects of small-scale restoration (less than downstream by new riparian or floodplain 20 per cent of the area of the woodland, although local upstream surface/groundwater body or catchment) properties would be at risk from the unlikely to be detected at the level of a main backwater effect and potential for large surface or groundwater body woody debris release to block critical • No effect on extreme flood flows. structures downstream (e.g. bridges and culverts) Knowledge gaps and research needs • Improvements to riverbank and in-stream physical habitat through bank protection, A combination of targeted field and modelling woody debris-dam formation, leaf fall and studies are required to: shading. • Quantify the impact of upland native woodland on water quantity and water Restoration of semi-natural open-ground quality at the catchment scale, as most habitats from conifer plantations hydrological studies have focused on conifer Restoration can be expected to benefit water plantations quantity, and to a lesser extent water quality, • Field test models and further quantify the depending on how these areas are subsequently impact that new native floodplain woodland managed. Adverse effects could result from can have on mitigating large flood events large-scale felling to waste, chemical and • Further quantify effects of targeted planting cultivation treatments to control conifer of native woodland on diffuse pollution regeneration, burning or use of livestock for within agricultural catchments, specifically vegetation management, although good practice in relation to infiltration basins/swales, will minimise these risks. In general, impacts riparian buffers, source areas and pollutant are expected to be: pathways • Local improvements in water quality greatest • Develop best practice on managing in acid-sensitive areas, where removal of the floodplain woodland in terms of benefits and scavenging effect will reduce the risk of acid potential threats (e.g. from the release of deposition contributing to acidification. large woody debris) to flood defence • Substantial reduction (up to 90 per cent) in • Quantify the water use of a wider range of nitrate concentrations in dry regions (less native woodland species and the effect of than 600–650 mm annual rainfall), as woodland design and structure on woodland conifers have a marked evaporation- evaporation concentration effect • Quantify the effects on flood flows and • Reduction in speed of surface run-off from diffuse pollution control of using woodland blocking forest drains and cultivation within sustainable urban drainage systems channels on peatland but countered by • Quantify the economic costs and benefits of increased volume of run-off and possible native woodland impacts on water and reduction in available soil water storage evaluate the case for payments for water • Increase in water yield and probably base services in the UK flows (by 50–100 per cent in dry regions and • Develop an improved climate change water up to 20 per cent in wet areas) use impacts model that can take account of • Increase in small (less than one in every five species differences under present and years) flood events (less than 20 per cent) projected climate scenarios to support operational decision-making • Quantify the impact of short-rotation forestry on water quantity and quality and identify the most water efficient species

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• Monitor the long-term effects of native area. Scale tends to be less important for water woodland on the freshwater environment. quality due to the localised nature of many Conclusion pollution sources and the success of targeted measures. Delivery of targets in the UK Biodiversity Action Plan for maintenance, restoration and There is an urgent need for further research expansion of native woodland, as well as to quantify the relative impact of native restoration of semi-natural open-ground woodland on water quantity and quality, as habitats from conifer plantations, could make compared to other land cover. It is vital that the important contributions to meeting some of the effect of continuing native woodland expansion objectives of the EU Water Framework on adjacent water bodies and groundwater Directive and provide some opportunities to supplies is assessed to build on current limited help meet the EU Floods Directive. evidence. An opportunity is presented at Loch Katrine, one of the most important public- The key interactions between woodland and water-supply reservoirs in Scotland, where water management are summarised below: Forestry Commission Scotland is initially • Broadleaved woodland can substantially planning to increase native woodland cover to improve water quality, as it removes the 2,000ha (18 per cent cover) with significant need for regular soil disturbance/cultivation scope for more. Planting of demonstration and fertiliser and pesticide treatments, floodplain woodland across the UK is also especially where it replaces potentially required to facilitate research and aid damaging land uses on sensitive soils (e.g. communication. improved grassland and arable overlying Acknowledgements soils prone to erosion and nutrient loss) • Annual water yield from broadleaved This work was funded by the Woodland Trust woodland is expected to be greater than and the Forestry Commission. We are grateful from conifer plantations but potentially less for comments received on drafts of the report than from grassland or arable. Risk of from: Steve Gregory, Helen McKay, Derek woodland creation reducing water yield Nelson and Sallie Bailey (Forestry depends on climate, geology and Commission); Mark Diamond (Environment management and can be managed by Agency); Nick Collinson, Fran Hitchinson and selecting species that use less water Mike Townsend (Woodland Trust). The document is a review and is not intended to • Woodland has the potential to reduce low reflect the policy positions of any of the flows. Risk is greatest for conifers on deeper organisations involved. lowland aquifers and lowest for broadleaved woodland on shallower upland aquifers Bibliography • Broadleaved woodland can reduce small Ahmad-Shah, A. and. Rieley, J.O. (1999) ‘muddy’ floods at a local scale and on Influence of tree canopies on the quantity of floodplains can mitigate large flood events, water and amount of chemical elements absorbing and delaying release of flood reaching the peat surface of a basin mire in the flows. Models suggest the impact of Midlands of England. Journal of Ecology, 77, floodplain woodland could be significant but pp. 357-370. field testing is required. Alexander and Cressner (1995) An assessment The impacts of woodland on water quantity of the possible impact of expansion of native tend to be related to the extent of woodland woodland cover on the chemistry of Scottish cover within a catchment. Effects are very freshwaters. Forest Ecology and Management, difficult to detect when woodland creation or 73, pp. 1-27. removal involves less than 20 per cent of the

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Best, A., Zhang, L., McMahon, T., Western, A. Calder, I.R., Reid, I., Nisbet, T.R., Armstrong, and Vertessy, R. (2003) A critical review of A., Green, J.C., and Parkin, G. (2002) Study of paired catchment studies with reference to the potential impacts on water resources of seasonal flows and climatic variability. proposed afforestation. Final report of contracts Murray-Darling Basin Commission and CWO 633-I and CWO 633II (Trees and CSIRO. Drought Project on Lowland England – TaDPoLE) to the Department for the Carroll, Z.L., Bird, S.B., Emmett, B.A., Environment, Food and Rural Affairs Reynolds, B. and Sinclair, F.L. (2004) Can tree publication, 179 pages. shelterbelts on agricultural land reduce flood risk? Soil Use and Management, 20, pp. 357- Calder, I.R., Reid, I., Nisbet, T.R., and Green, 359. J.C. (2003) Impact of lowland forests in England on water resources: application of the Bosch, J.N. and Hewlett, J.D. (1982) A review Hydrological Land Use Change (HYLUC) of catchment experiments to determine the model. Water Resources Research, 39, 1319 effect of vegetation changes on water yield and pages. evapotranspiration. Journal of Hydrology, 55, pp. 3–23. Calder, I.R. (1990) Evaporation in the uplands. John Wiley and Sons, Chichester, 148 pages. Bradshaw, C.J.A., Sodhi, N.S., Peh, K.S.-H. and Brook, B.W. (2007) Global evidence that Calder, I.R. (2005) Second Edition The Blue deforestation amplifies flood risk and severity Revolution, Integrated Land and Water in the developing world. Global Change Resource Management, Earthscan Publications, Biology, 13, pp. 1-17. London, UK, 352 pages. Broadmeadow, S. and Nisbet, T. (2004) The Calder, I.R. and Aylward, B. (2006) Forests and effects of riparian forest management on the floods: moving to an evidence-based approach freshwater environment: a literature review of to watershed and integrated flood management. best management practice. Hydrology and Water International, 31, issue 1, pp. 87-99. Earth System Sciences, 8, Issue 3, pp. 286-305. Calder, I.R., Nisbet, T. and Harrison, J.A (2007) Bromley, M. (2006) Forestry and the water An evaluation of the impacts of energy framework directive - an update. Agenda Item plantations on water resource in the UK under 5, National Committee for Wales, Forestry present and future UKCIP02 climate scenarios. Commission, Wales, 4 pages. Contract Report to Forestry Commission (in press). Calder, I.R., Harding, R.J. and Rosier, P.T.W. (1983) An objective assessment of soil moisture Cameron, D. (2006) An application of the deficit models. Journal of Hydrology, 60, pp. UKCIP02 climate change scenarios to flood 329-355. estimation by continuous simulation for a gauged catchment in the northeast of Scotland, Calder, I.R., Hall, R.L., Rosier, P.T.W., UK (with uncertainty). Journal of Hydrology, Bastable, H.G., and Prasanna, K.T. (1996) 328, pp. 212-226. Dependence of rainfall interception on drop size: 2. experimental determination of the Cannell, M.G.R. (1999) Environmental impacts wetting functions and two-layer stochastic of forest monocultures: water use, acidification, model parameters for five tropical tree species. wildlife conservation and carbon storage. New Journal of Hydrology, 185, pp. 379-388. Forests, 17, pp. 239-262. Calder, I.R., Harrison, J., Nisbet, T.R. and Carling, P.A., Irvine, B.J., Hill, A. and Wood, Smithers, R.J. (2008) Woodland actions for M. (2001) Reducing sediment inputs to Scottish biodiversity and their role in water streams: a review of the efficacy of soil management. Woodland Trust, Grantham.

161 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 conservation practices in upland forestry. The Dudley, N. and Stolton, S. (2003) Running Science of the Total Environment, 265, pp. 209- Pure: The importance of forest protected areas 227. to drinking water. World Bank and WWF Alliance for Forest Conservation and Castelle, A.J., Johnson, A.W. and Connolly, C. Sustainable Use publication, 114 pages. (1994) Wetland and stream buffer size requirements- a review. Journal of Duncan, H.D., Langford, K.J. and Environmental Quality, 23, pp. 878-882. O’Shaughnessy, P.J. (1978) A comparative study of canopy interception. Proceedings of Chomitz, K.M. (2006) At Loggerheads? Institute of Engineering Australia, Hydrology Agricultural expansion, poverty reduction and and Water Resources Symposium, Canberra, environment in the tropical forests. World Bank Institute of Engineers, Canberra, pp 150-154. Policy Research Report, Washington, D.C. Environment Agency (1998) Broadleaf Cook, D, Greeenaway, T. and Southgate, F. woodlands: the Implications for water quantity (2005) Sussex Floodplain Forest Concept and quality. Environment Agency R&D Study. Report of the Record Centre Survey Publication, No. 5, 37 pages, The Stationery Unit, 139 pages. Office, London. Cornish, P.M. (1993) The effects of logging and Fahey, B. and Jackson, R. (1997) Hydrological forest regeneration on water yields in a moist impacts of converting native forests and eucalypt forest in New South Wales, Australia. grasslands to pine plantations, South Island, Journal of Hydrology, 150, pp. 301-322. New Zealand. Agricultural and Forest Curry, R.A., Scruton, D.A., and Clarke, K.D. Meteorology, 84, pp. 69-82. (2002) The thermal regimes of brook trout Food and Agriculture Organisation (2005) incubation habitats and evidence of changes Forests and floods: drowning in fiction or during forestry operations. Canadian Journal of thriving on facts. RAP publication 2005/03, Forest Research, 32, issue 7, pp. 1200-1207. Forest Perspectives 2. Food and Agriculture Davies-Colley, R.J. (1997) Stream channels are Organisation, Regional Office for Asia and the narrower in pasture than in forest. New Zealand Pacific: Bangkok, Thailand. Journal of Marine and Freshwater Research, Farley, K.A., Jobbagy, E.G. and Jackson, R.B. 31, pp. 599-608. (2005) Effects of afforestation on water yield: a Defra (2006a) England’s trees, woods and global synthesis with implications for policy. forests: a consultation document. Department Global Change Biology, 11, pp. 1565-1576. for the Environment Food and Rural Affairs, 53 Forestry Commission (1999) A New Focus For pages. England’s Woodlands: Strategic Priorities And Defra (2006b) Water supply in the long term - Programmes. England Forestry Strategy, 36 Water Saving Group outlines progress on action pages. plan. Department for the Environment Food Forestry Commission (2000) Forests for and Rural Affairs, News Release, 20 June 2006. Scotland. The Scottish Forestry Strategy, 92 Delzon, S. and Loustau, D. (2005) Age-related pages. decline in stand water use: sap flow and Forestry Commission (2001) Woodland for transpiration in a pine forest chronosequence Wales, Wales’ Forestry Strategy, 48 pages. Agricultural and Forest Meteorology, 129, pp. 105-199. Forestry Commission (2003) Forests and Water Guidelines, Fourth edition, Forestry Commission, Edinburgh, 66 pages.

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Forestry Commission (2005) Forestry Statistics D.C. (1996) Hydrological effects of short 2005. rotation coppice. Institute of Hydrology report http://www.forestry.gov.uk/website/foreststats.n to the Energy Technology Support Unit, sf/byunique/woodland.html. Institute of Hydrology: Wallingford, UK. Fuhrer, H.W. (Ed.) (2002) Wald und Wasser- 30 Harding, R.J., Hall, R.L., Neal, C., Roberts, Jahre forsthydrologische Untersuchungen im J.M., Rosier, P.T.W. and Kinniburgh, D.K. Krofdorfer Forst. Hessen-Forst FIV, Report No. (1992) Hydrological impact of broadleaf 29. woodlands: Implications for water use and water quality. Institute of Hydrology, British Gagkas, Z., Heal, K. Stuart, N. and Nisbet, T.R. Geological Survey Project Report 115/03/ST (2006) Forests and Water Guidelines: and 115/04/ST for the National Rivers broadleaved woodlands and the protection of Authority, Institute of Hydrology: Wallingford, freshwaters in acid-sensitive catchments. UK. Forestry Commission, Edinburgh, 66 pages. Hardcastle, P.D. Review Team Leader (2005) A Gash, J.H.C. and Stewart, J.B. (1977) The review of the potential impacts of short rotation evaporation from Thetford forest during 1975. forestry – final report. LTS International. Journal of Hydrology, 35, pp. 385-396. Haycock, N.E. and Pinay, G. (1993) Gill, G. and Patterson, G. (no date) Global Groundwater nitrate dynamics in grass and Partnership on Forest Landscape Restoration: poplar vegetated riparian buffer strips during Investing in People and Nature. Kielder Forest, the winter. Journal of Environmental Quality, United Kingdom. 22, issue 2, pp. 273-278. Globevnik, L. (2006) Effects of forest cover Haydon, S.R., Benyon, R.G. and Lewis, R. change on the runoff regime of the Dragonja (1996) Variation in sapwood area and River in Slovenia. Abstract from the scientific throughfall with forest age in mountain ash forum of the International Congress on (Eucalyptus regnans F. Muell). Journal of Cultivated Forests 3rd-7th October 2006, Hydrology, 187, pp. 351-366. Bilbao, Spain, 65 pages. Howorth, R. and Manning, C. (2001) Land use Green, J.C., Reid, I., Calder, I.R. and Nisbet, change and the water environment of the West T.R. (2006) Four-year comparison of water Weald landscape over a 30-year period (1971- contents beneath a grass ley and a deciduous 2001). Report for Sussex Wildlife Trust and the oak wood overlying Triassic sandstone in Environment Agency, Sussex area, 34 pages. lowland England. Journal of Hydrology, 329, pp. 16-25. Hibbert, A.R. (1967) Forest treatment effects on water yield. In: Sopper, W.E. and Lull, H.W. Hall, R.L. (1994) Hydrological aspects of (Eds.) International Symposium for Hydrology, broadleaved woodland: Implications for water Pergamon, Oxford, 813 pages. supply. Forests and water. Proceedings of a discussion meeting, Heriot Watt University, Hughes, F.M.R. (Ed.) (2003) The Flooded Edinburgh. Institute of Chartered Foresters, pp. Forest: Guidance for policy makers and river 44-60. managers in Europe on the restoration of floodplain forests. FLOBAR2, Department of Hall, R.L. (2003) Short rotation coppice for Geography, University of Cambridge, UK. 96 energy production: hydrological guidelines. pages. DTI New and Renewable Energy Programme: B/CR/00783/GUIDELINES/SRC URN 03/883. Hall, R.L., Allen, S.J., Rosier, P.T.W., Smith, D.M., Hodnett, M.G., Roberts, J.M., Hopkins, R., Davies, H.N., Kinniburgh, D.G. and Goody,

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Holman, I.P. and Loveland, P.J. (Eds.) (2002) 2001). A re-survey and analysis of change REGIS: Regional Climate Change Impact based on the 103 sites in the Nature Response Studies in East Anglia and North Conservancy ‘Bunce 1971’ woodland survey. West England. UK Climate Impacts English Nature Research Reports, number 653, Programme, Oxford. www.ukcip.org.uk. 139 pages. Hsia, Y.J. and Koh, C.C. (1982) Water yield Kitteridge, J. (1948) Forest Influences. resulting from clearcutting a small hardwood McGraw-Hill, New York, 394 pages. basin in central Taiwan. In: Keller, R. (Ed.) Hydrology of Humid Tropical Regions. Kuczera, G.A. (1987) Prediction of water yield Proceedings of a symposium held during the reductions following a bushfire in ash-mixed 18th General Assembly of the IUGG in species eucalypt forest. Journal of Hydrology, Hamburg, Germany. International Association 94, pp. 215-236. of Hydrological Sciences Publication, 140, pp. Link, T.E., Unsworth, M. and Marks, D. (2004) 215-220. The dynamics of rainfall interception by a Ilstedt, U., Malmer, A., Verbeeten, E. and seasonal temperate forest. Agricultural and Murdiyarso, D. (2006) The effect of Forest Meteorology, 124, pp. 171-191. afforestation on water infiltration in the Linstead, C. and Gurnell, A.M. (1998) Large Tropics: a systematic review and meta-analysis. woody debris in British headwater rivers. Oral presentation at the International Congress Physical habitat role and management on Cultivated Forests, 3rd-7th October 2006: guidelines. R&D Technical Report W185. Bilbao, Spain. Environment Agency: Bristol, UK. Irvine, J., Law, B.E., Kurpius, M.R., Anthoni, Llorens, P. and Gallart, F. (2000) A simplified P.M., Moore, D. and Schwarz, P. (2004) Age- method for forest water storage capacity related changes in ecosystem structure and measurement. Journal of Hydrology, 240, pp. function and effects on water and carbon 131-144. exchange in ponderosa pine. Tree Physiology, 24, pp. 753-763. Lowrance, R., Todd, R., Fail Jr., J., Hendrickson Jr., O., Leonard, R. and Asmussen, Jackson, R.B., Jobbagy, E.G., Avissar, R., Roy, L. (1984) Riparian Forests as Nutrient Filters in S.B., Barrett, D.G., Cook, C.W., Farley, K.A., le Agricultural Watersheds. BioScience, 34, pp. Maitre, D.C., McCarl, B.A. and Murray, B.C. 374-377. (2005) Trading water for carbon with biological carbon sequestration. Science, 23, 310, pp. Lynch, J.A., Corbett, E.S., and Mussallem, K. 1944-1947. (1985) Best management practices for controlling non-point source pollution on Jacob (2006) Overview of climate change forested watersheds. Journal of Soil Water projections in Europe. International Workshop Conservation, 40, pp. 87-91. on Climate Change Impacts in the Water Cycle, Resources and Quality. 25-26th September McCulloch, J.S.G. and Robinson, M. (1993) 2006: Brussels, Belgium. History of forest hydrology. Journal of Hydrology, 150, pp. 189-216. Jayasuriya, M.D.A., Dunn, G., Benyon, R. and O’Shaughnessy, P.J. (1993) Some factors Metcalfe, R.A and Buttle, J.M. (1999) Semi- affecting water yield from mountain ash distributed water balance dynamics in a small dominated forests in south-east Australia. boreal forest basin. Journal of Hydrology, 226, Journal of Hydrology, 150, pp. 345-367. pp. 66-87. Kirby, K.J., Smart, S.M., Black, H.I.J., Bunce, Mills, D. H. (1980) The management of forest R.G.H. and Smithers, R.J. (2005) Long term streams. Forestry Commission Leaflet no. 78, ecological change in British woodland (1971- London: HMSO.

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Moore (1999) Forests, hydrology and water Nisbet, T.R. (2005) Water use by trees. quality: impacts of silvicultural practices. Information note for the Forestry Commission, University of Florida, Institute of Food and 8 pages. Agricultural Sciences, pp.13. http://edis.ifas.ufl.edu/FR009#disc. Nisbet, T.R., Orr, H. and Broadmeadow, S. (2004) A guide to using woodland for sediment Neal, C. (2002) Interception and attenuation of control. Forest Research, 6 pages. atmospheric pollution in a lowland afforested site, Old Pond Close, Northamptonshire, UK. Nisbet, T.R. and Thomas, H. (2006) The role of Science of the Total Environment, 282-283, pp. woodland in flood control: a landscape 99-119. perspective. In: Davies, B.R. and Thompson, S. (Eds.) Water and the Landscape: The Neal, C., Robson, A.J., Hall, R.L., Ryland, G., Landscape Ecology of Freshwater Ecosystems, Conway, T. and Neal, M. (1991) Hydrological Proceedings of the fourteenth annual impacts of hardwood plantation in lowland IALE(UK) conference, International Britain: preliminary findings on interception at Association of Landscape Ecology (UK), pp. a forest edge. Journal of Hydrology, 127, pp. 118-125. 349-365. Nisbet, T.R. and Stonnard, J.S. (1995) The Neal, C. and Reynolds, B. (1998) The impact of impact of forestry on low flow regime - an conifer harvesting and replanting on upland analysis of long-term streamflow records from water quality. EA R&D Technical Report P211, upland catchments. In: Black, A.R. and Environment Agency: Bristol. Johnson, R.C. (Eds.) Proceedings of the Fifth National Hydrological Symposium, Institute of NEGTAP (2001) National Expert Group on Hydrology: Wallingford, OXON, pp 7.25-7.30. Transboundary Air Pollution: Acidification, Eutrophication and Ground Level Ozone in the Nunez, D., Nahuelhaul, L. and Oyarzun, C. UK. 1st report. On behalf of the UK (2006) Forests and water: the value of native Department of the Environment, Transport and temperate forests in supplying water for human the regions and the devolved administrations. consumption. Ecological Economics, 58, pp. www.nbu.ac.uk/negtap/finalreport.htm. 606-616. NERC (1975) The flood studies report, 4. O’Connell, P.E., Bevan, K.J., Carney, J.N., Natural Environment and Research Council, Clements, R.O., Ewen, J., Fowler, H., Harris, London. G.L., Hollis, J., Morris, J., O’Donnell, G.M., Packman, J.C., Parkin, A., Quinn, P.F., Rose, Newson, M.D. and Calder, I.R. (1989) Forests S.C., Shephard, M. and Tellier, S. (2004) and water resources: problems of prediction on Project FD214: Review of impacts of rural land a regional scale. Philosophical Transactions of use and management on flood generation. the Royal Society of London, 324, pp. 283-298. Defra R&D Technical Report FD2114. Defra: Nisbet, T.R. (2001) The role of forest London. management in controlling diffuse pollution in Penman, H.L. (1948) Natural Evaporation from UK forestry. Forest Ecology and Management, Open Water, Bare Soil and Grass. Proceedings 143, pp. 215-226. of the Royal Society of London. Series A, Nisbet, T.R. (2002) Implications of climate Mathematical and Physical Sciences, 193, pp. change: soil and water. In: Broadmeadow, M. 120-145. (Ed.) Climate change: impacts on UK forests, Pizarro, R., Araya, S., Jordan, C., Farias, C., Forestry Commission Bulletin 125, pp 53-67. Flores, J.P. and Bro, P.B. (2006) The effects of Forestry Commission, Edinburgh changes in vegetative cover on river flows in the Purapel river basin in central Chile. Journal of Hydrology, 327, pp. 249-257.

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Pinay, G., Roques, L. and Fabre, A. (1993) those from other woodland and grassland sites. Spatial and Temporal Patterns of Denitrification Hydrology and Earth System Sciences, 9, issue in a Riparian Forest. Journal of Applied 6, pp. 614-620. Ecology, 30, issue 4, pp. 581-591. Roberts, S., Vertessy, R. and Grayson, R. Postel, S.L. (2000) Entering an era of water (2001) Transpiration from Eucalyptus sieberi scarcity: the challenges ahead. Ecological (L. Johnson) forests of a different age. Forest Applications, 10 (4), pp. 941-948. Ecology and Management, 143, pp. 153-161. Price (2005) Loch Katrine: Land use change Robinson, M., Cognard-Planq, A.L., Cosandey, impacts to yield. Contract report from Jacobs C., David, J., Durand, P., Fuhrer, H.W., Hall, Babtie to Scottish Water. R., Hendriques, M.O., Marc, V., McCarthy, R., McDonnell, M., Martin, C., Nisbet, T., O’Dea, Puplett, D. (2003) Riparian Woodlands. Trees P.O., Rogers, M. and Zollner, A. (2003) Studies for Life newsletter, Caledonia Wild! Summer of the impacts of forests on peak flows and 2003, baseflows: a European perspective. Forest http://www.treesforlife.org.uk/forest/ecological/ Ecology and Management, 186, pp. 85-97. riparianwoodland. Robinson, M. and Dupeyrat, A. (2003) Effects Putuhena, W.M. and Cordery, I. (2000) Some of commercial forest felling on streamflow hydrological effects of changing forest cover regimes at Plynlimon, mid-Wales. Hydrological from eucalypts to Pinus radiata. Agricultural Processes, 19, pp. 1213-1226. and Forest Meteorology, 100, pp. 59-72. Rutter, A.J. (1963) Studies in the water Rackham, O. (2006) Woodlands. Collins New relations of Pinus sylvestris in plantation Naturalists Series. conditions, I. Measurements of rainfall and Rakhmanov, V.V. (1962) Role of forests in interception. Journal of Ecology, 51, pp. 191- water conservation. Israel Program for 203. Scientific Translations, Jerusalem, 1966, 192 Scott, D.F., Prinsloo, E. and Moses, G. (2006) pages. The long-term effects of Pine and Eucalypt Rice, T. (2005) Sustainable forestry in the UK. plantations on streamflow, and a possible link Friends of the Earth’s Paper to the Government to site productivity. Extended Abstracts from Panel on Sustainable Development – Forests. the Conference on Forests and Water in a http://www.foe.co.uk/resource/consultation_res Changing Environment, Beijing, China, August ponses/sustainable_forestry_uk.html on 2006. 10/10/2006. Scottish Native Woods (1996) Restoring and Roberts, J.M. (1983) Forest transpiration: a managing riparian woodlands. Scottish Native conservative hydrological process? Journal of Woods Booklet. Hydrology, 66, pp. 229-245. Stanley, B. and Arp, P.A. (2002) Effects of Roberts, J.M. and Rosier, P.T.W (1994) forest harvesting on basin-wide water yield in Comparative estimates of transpiration of ash relation to the percentage of watershed cut: a and beech forest at a chalk site in southern review of literature. Nexfor/Bowater Forest Britain. Journal of Hydrology, 162, pp. 229- Watershed Research Centre, Faculty of Forestry 245. and Environmental Management UNB, Fredericton, NB, 35 pages. Roberts, J.M. and Rosier, P.T.W. (2005) The impact of broadleaved woodland on water Sun, G., Zhou, G., Zhang, Z., Wei, X., McNulty, resources in lowland UK: III. The results from S.G. and Vose, J.M. (2006) Potential water yield Black Wood and Bridgets Farm compared with reduction due to forestation across China. Journal of Hydrology, 328, pp. 548-558.

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Sutton, M.A., Fowler, D. and Moncrieff, J.B. Wei, X., and Davidson, G.W. (1998) Impacts of (1993) Exchange of atmospheric ammonia with large scale timber harvesting on the hydrology vegetation surfaces. I. Unfertilised vegetation. of the Bowron River Watershed. In: Quarterly Journal of Royal Meteorological Proceedings of Mountain to Sea: Human Society, 119, pp. 1023-1045. interaction with the hydrological cycle. Canadian Water Resource Association 51st Swaine, M.D., Adomako, J., Ameka, G., Ade National Conference in Victoria, June 10-12th, Graft-Johnston, K.A. and Cheek, M. (2006) pp. 45-52. Forest river plants and water quality in Ghana. Aquatic Botany, 85, Issue 4, pp. 299-308. Williams, A.G., Kent, M. and Kernan, T.L. (1987) Quantity and quality of bracken Thomas, H. and Nisbet, T. (2006) An throughfall, stemflow and litterflow in a assessment of the impact of floodplain Dartmoor catchment. Journal of Applied woodland on flood flows. Water and Ecology, 24, pp. 217-230. Environment Journal, pp. 1747-6585. Wullschleger, S.D., Wilson, K.B. and Hanson, Thompson, R., Humphrey, J., Harmer, R. and P.J. (2000) Environmental control of whole- Ferris, R. (2003) Restoration of native plant transpiration, canopy conductance and woodland on ancient woodland sites. Forestry estimates of the decoupling co-efficient for Commission practice guide, 52 pages. large red maple trees. Agricultural and Forest UNECE (2006) Payments for ecosystem Meteorology, 104, pp. 157-168. services in integrated water resources Zhou, M.C., Ishidaira, H., Hapuarachchi, H.P., management. Fourth meeting Bonn (Germany), Magome, J., Kiem, A.S. and Takeuchi, K. 20–22 November 2006. Item 6 (b) of the (2006) Estimating potential evapotranspiration provisional agenda. using Shuttleworth–Wallace model and NOAA- Viramontes, D. and Descroix, L. (2003) AVHRR NDVI data to feed a distributed Changes in the surface water hydrologic hydrological model over the Mekong River characteristics of an endoreic basin of northern basin. Journal of Hydrology, 327, pp. 151-173. Mexico from 1970 to 1998. Hydrological Zon, R. (1927) Forests and Water in the Light Processes, 17, pp. 1291-1306. of Scientific Investigation. U.S. Department of Wakeel, A., Rao, K.S., Maikhuri, R.K. and Agriculture, Government Printing Office: Saxena, K.G. (2005) Forest management and Washington D.C. 106, 1927 pages. land use/cover changes in a typical micro watershed in the mid elevation zone of Central Himalaya, India. Forest Ecology and Management, 213, pp. 229-242. Watson, F.G.R., Vertessy, R.A. and Grayson, R.B. (1997) Large scale, long term, physically based prediction of water yield in forested catchments. Proceedings, International Congress on Modelling and Simulation (MODSIM 97): Hobart, Tasmania, 8-11 December, pp. 397-402. Webber, J., Gibbs, J.N. and Hendry, S. (2004) Phytophthora disease of alder. Forestry Commission Information Note 6 (Third edition), 6 pages.

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The Summer 2007 Floods - A Plea for Land Management Based Flood Risk Solutions Rob Stoneman Yorkshire Wildlife Trust

To say that the summer of 2007, or more un-farmable as blanket bog formed in the late specifically May to July of 2007, was a tad wet Bronze Age; the floodplains were impassable would be a classic bit of British understatement morasses; the Fens a vast wilderness of for the weather was truly awful.Around 415mm freshwater reed and salt-marsh. The of rain fell on South Yorkshire between May preponderance of archaeological structures on and July1, much of it on June 25th. This 1:200 the drier chalk hills or the line of a Roman year flood alongside further heavy rain in July Road hugging the high ground (e.g. the A1 on caused the flooding of some 55,000 homes the magnesium limestone ridge) is no across England; the insurance pay-out ran to £3 coincidence – the land was simply too wet billion1. Not quite a New Orleans catastrophe elsewhere. but utterly devastating for those residents of Today, our landscape is massively drained. Toll Bar who celebrated Christmas in cold Virtually every field is beset with drains, urban caravans six months on from the flood. areas riddled with a network of underground Notably, two-thirds of the houses flooded were sewers and the great English fenland dyked, affected by surface water flooding rather than drained and pumped to get water from the land more usual river flooding. to rivers that now actually flow above the land It is worth thinking though the origins of this in straight-lined canals. Even from our upland crisis and what better place to begin than on the vantage point where we start this story, high in hills overlooking Sheffield, on which its rivers the Pennines, drainage is intense with most – the Sheaf, Don, Loxley and Rivelin – start blanket bogs extensively gripped (drained with their journeys through the city and out to the narrow ditches) to improve grazing. This had Humber estuary, only 40 miles downstream. All little effect on grazing but was paid for by the around is blanket bog, a once-Sphagnum rich UK tax-payers under Ministry of Agriculture mosaic of heather and cotton grass home to diktat from the 1950s to 1970s. golden plover, twite and hen harrier. Where once was healthy bog, with its In this simple description, we can begin to spongy upper layer acrotelm of Sphagnum that dissect the root causes of the flooding crisis, for can absorb significant quantities of water, now Britain is a manifestly wet country. Blanket bog there is often rotationally burnt heather or only forms in the most exacting of climates – at cotton grass. The hydrology has been least a 1,000mm of rain per year, over 150 days significantly altered to something more akin to that are wet (or foggy)2 alongside mild winters, a car-park. The ability of the uplands to store i.e. not crisp winter wonderlands but drench to water has been substantially reduced4. The race the bones rain and drizzle of a wet British from rain to urban drain to catastrophic flood is winter. Indeed, blanket bog is globally set in motion. exceptionally rare, at its zenith in Britain and On the Pennine fringe, high stocking Ireland and also found in other hyper-oceanic densities encouraged by the ‘headage’ places such as Iceland or the Falklands3. production subsidy payments of the 1980s To farm or build settlement in these isles causes compaction and up to an 80% reduction requires drainage. Once deforested by our in surface infiltration by rain-water5. Severe ancestor farmers, the uplands quickly became flooding by the Swale and Ure has been

168 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 directly attributed to over-grazing of the Dales,6 below the rivers is pump-drained with water for example. Still on the fringe, the car-park pumped up through ditches and drains into the effect continues on the actual car-parks of main rivers to speed out to sea between high urban Sheffield, where in common with many embankments. As the land dries, the peat cities, acres of front-garden are now paved over oxidises and so the land sinks leaving some of to make room for car-parking. Urban the fens actually below sea-level or former landscapes are highly impermeable to rainwater river beds (composed of silt rather than peat) although parks, gardens and development sites standing proud of the land they used to run (or waste ground) provide some ability to store across. rain-water and allow infiltration. It rarely happens but should peak-flow over- Traditionally, storm water is fed into top these river embankments, the effects are underground sewers and culverts to speed the truly calamitous as water cascades into a flow of rainwater, falling on roads, roofs and landscape entombed by those river car-parks, to urban rivers. This increases peak- embankments and sea-walls. The land fills up flow. The Department for the Environment, like a bath-tub requiring costly and time- Food and Rural Affairs (DEFRA)7 bluntly consuming pumping to rid the land of the assess that, “below-ground piped systems can water. Worse still, rain falling on developed never be built large enough to cope with the land beneath the embankments (e.g. Hull or most extreme events”. At worst, sub-surface parts of Doncaster) has to be pump drained up drainage systems fail across the whole city. into the rivers. This is fine for normal storms Low-lying Hull flooded not because of over- but impossible for the 1:200 year storm. In topping by the River Hull (it didn’t), rather Hull, this system is even more constrained as a because the city’s drainage system could never bank-full River Hull could only have water have coped with the intense rainfall of 25th pumped into it at low tide as the high tide acts June 2007. as a dam pushing water back upstream to flood farmland above Hull. Moving down catchment, urban development of the floodplain (Rotherham, for It comes down to a cost-benefit analysis. example) makes matters worse as city Society takes a risk when it over-grazes the engineers attempt to cope by deepening river uplands, paves over urban greenspace, develops channels and building flood walls and banks in the floodplain or drains coastal wetlands. It through urban areas. These defences usually mitigates that risk by building flood defences work as water speeds through to the sea, but for the most valuable (built on) land and tacitly flood defences can never protect a floodplain accepts inevitable failure ever 100 years of so. from the most extreme events. With 35,000 Some of this risk is rather carefully modelled homes at risk from catchment flooding in the where flood defences are built or maintained in Don-Rother-Dearne catchment alone7, failure relation to flood regularity and economic value is, and was in 2007, catastrophic. of the land and buildings protected. Government, through the Environment Agency Agricultural intensification, whether pastoral and Local Authorities, might assess that an or arable, can reduce infiltration. Add to this acceptable risk of over-topping is once every 50 the effects of peatland and urban drainage and years using historical data to build the model. the risks accumulate with increasing volumes Failure is thus designed into flood defence (in of water crowding into the peak-flow. Peak- truth, EA have little choice) as at some point in flows become shorter but higher and it is in the the next 50 years, over-topping will occur with drained coastal fenland of the lower catchment all its misery and insurance pay-out. Of course, that the risks mount ever higher. Former the EA cannot predict when that might be and fenland rivers, such as the lower Don, have the model rests on a huge assumption: that the been canalised as part of Vermuyden’s past is a guide to the future. In an era of rapid seventeenth century drainage scheme. The land climate change, this assumption becomes

169 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 almost useless – the risk gets ever more about the same amount as Britain’s difficult to assess. Actually, the Government7 transportation system produces each year. have attempted to assess the effect of a However, restoration of those bogs could lead changing climate, assessing that flood risk is set to a reversal of loss to sequestration of about to increase by between two to twenty times 400,000 tonnes of carbon per year11. Peatland present risk by 2080. To put that another way, restoration clearly has a very substantial role to our 1:200 year June flood might happen once a play in Britain’s attempts to mitigate climate decade by 2080. change. Given that present land management Furthermore, Yorkshire Water currently practices contribute to increased peak-flow, it spends millions on dealing with peat-stained surely makes sense to seek to reduce this risk water colour that is unacceptable in tap water by addressing the way we manage water in the (although harmless). Colour is directly landscape. Let us return to the Pennines. attributable to blanket bog burning and drainage through the oxidation of peat11. It On the high Pennine blanket bogs, gripping seems crazy that Yorkshire Water owned is fairly easy to reverse. Simple ditch blocking blanket bog is still burned and gripped despite 3 using peat dams or cheap ply-board is straight- the millions of water-payers’ money spent on forward. More problematic is the blocking of dealing with the problem. major gullies or re-vegetating bare peat surfaces. Moors for the Future8 has successfully In short, upland peat bog restoration is the trialed a variety of techniques in the Peak ultimate ecological ‘win-win’: reduced peak- District. Gully blocking using straw bales, coir flow, climate change mitigation, a reduction in rolls and pilings and fertilising bare peat with water colour (and subsequent cost of treatment) limestone and sowing nurse grass crops provide as well as the conservation of one of the a starting point for moorland plants to world’s rarest habitats. These ‘wins-wins’ can recolonise the badly eroded moors. Reducing be extended into the city though sustainable sheep stocking and avoiding blanket bog drainage systems (SuDS). SuDS seeks to burning is also essential. accommodate storm water (surface water flow) through infiltration to ground water, temporary Away from the blanket bogs, a reduction in water storage and enhanced evapotranspiration stocking density is likely to lead to increasing using a mix of permeable surfaces (such as water infiltration as compaction lessens, urban greenspace), increased evapotranspiration reducing surface flow (and hence peak flow). through vegetation (especially trees), shallow Less intensive farming of the upper catchments ditches (swales) and temporary storage basins might have a role to play in reducing peak-flow (pond or shallow basins). although an Environment Agency review of literature found mixed evidence9. However, In Sheffield, as part of the regeneration of regardless of the flood-peak effect, less the Manor estate, a SuDS was incorporated into intensive land-use, moorland grip blocking and the design of a new housing estate and a cessation of blanket bog burning would have refurbished park. Here water runs off the road a significant positive effect on wildlife. Blanket into a system of swales that feed into a large bog is globally rare2 and protected under the infiltration basin which in turn feeds into a Habitats Directive. Rejuvenating Sphagnum stream. In the June 2007 flood, the basin duly cover and peat formation both protects this rare filled up with storm-water but did not over-top, habitat and sequesters carbon from the rather safely infiltrating into the ground over atmosphere. the next week or so and presumably substantially lessening flooding lower down the Indeed, the amount of carbon that is Carbrook. Moreover, the SuDS basin is used as currently lost each year by the UK’s mostly an events area when it is dry (i.e. most of the drained blanket bog is staggering: perhaps as year) whilst the ponds, wet swales and streams much as 381,000 tonnes of carbon per year10 or

170 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 abound with wildlife and interest. By-the-by, it storm events. Clifton Ings, for example, in was also about £1 million cheaper to construct north York can store 2.3m3 of water equating to than the originally envisaged sub-surface storm a drop in peak-flow through York of 15cm7. In water sewers that Sheffield Wildlife Trust Rotherham, development close to the floodplain (SWT) consistently argued against. Sadly, has had its risk of flooding reduced through the SWT’s cogent arguments were ignored until development of the Centenary Riverside high costs made the underground system washland. Here, Sheffield Wildlife Trust are impractical. The Manor SuDS is now managed working with Rotherham Council and the by the Green Estate Company as part of its Environment Agency to develop a nature social enterprise business. reserve washland that provides an attractive back-drop to the regeneration of Rotherham This example demonstrates the ease and and can also be used for environmental 7 sense of SuDS. The Government sets this out education. The project has also been ear- plainly arguing, “managing surface water more marked for a pillwort translocation project, sustainably will involve increased reuse of protecting one of South Yorkshire’s rarest water, through rainwater capture and plants. harvesting; more absorption of water by the ground and also through increased use of green Downstream and just over the Don roofs; and increased above-ground storage catchment boundary, Yorkshire Wildlife Trust before routing of surface water separate from manage Potteric Carr Nature Reserve. Through the foul sewer system” (pp 58). Regrettably the middle of the reserve lies the Mother Drain SuDS take up is slow. The Pitt Review1 – a Vermuyden drain that allowed South identifies SuDS management issues and the Doncaster to develop from the once fens of the automatic right to connect to a public sewer as Upper Humberhead Levels. From Potteric Carr, barriers to SuDS implementation. water in the Mother Drain is pumped up into the River Torne and eventually into the River SuDS need not be complex for they include Trent and out into the Humber. Potteric Carr is simple measures such as garden water butts, another designed washland, storing huge permeable paving, soak-aways, larger areas of volumes of water, reducing peak-flow and thus urban soil or more wonderful ideas such as helping to protect South Doncaster (rather than green roofs (that increase evapotranspiration). storm water backing up the Mother Drain and And once again, all of these approaches have into Doncaster, it spreads out across the multiple benefits. A view of greenspace reduces reserve) and villages further down the River urban stress and speeds up recovery from Torne. It is also a flagship reserve for Yorkshire 12 illness . Urban trees intercept rainfall lessening Wildlife Trust with its visitor and education 13 the likelihood of flash flooding, significantly facilities and a mecca for birders who travel 14 reduce summer temperatures in towns , filter from afar to see its wintering bitterns and 15 16 out particulate pollution , reduce noise and breeding black-necked grebes amongst many 17 tend to lead to higher house prices . Parks, other highlights. gardens, allotments and green city squares are part of the mix that makes for fine cities rather In all of these examples, it is clear that land- than urban hells. based flood risk reduction schemes have multiple benefits. Carbon sequestration, habitat Where floodplains have been developed, and species conservation, drinking water hard flood defences are required to protect ‘colour’ amelioration, health and recreation valuable infrastructure although, of course, its benefits, landscape improvements, insurance makes sense (and always did) to build out of premium reduction, pollution amelioration, harm’s way for flood-plains are always likely to environmental education, visitor attractions... flood. To reduce peak-flow through urban this is a mightily impressive list. areas, flood risk engineers have long relied on creating washlands that store water during

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For sure, land based solutions to reduce 10 Bellamy, P.H., Loveland, P.J., Bradley, R.I., flood risk can only be part of the answer; some Lark, R.M. and Kirk, G.J.D. (2005) Carbon hard flood defence is always likely to be losses from all soils across England and Wales required (unless we re-located our cities). In 1978 – 2003. Nature, 437, 245-248. simple economic terms, though, these land- 11 based solutions offer amazing value for money Moors for the Future (2007) Peak District given the host of ecosystem services that ensue. Moorland Carbon Flux. Moors for the Future Research Note 12.

12 Ulrich, R.S. (1984) View through a window References may influence recovery from surgery. Science, 224, 420-21. 1 Cabinet Office (2007) Learning lessons from the 2007 floods. An independent review by Sir 13 See www.ciria.org.uk/suds Michael Pitt. HM Government 14 Huang, Y.J., Akbari, H., Taha, H. & 2 Lindsay, R.A., Charman, D.J., Everingham, F., Rosenfeld, A.H. (1987) The Potential of O’Reilly, R.M., Palmer, M.A., Rowell, T.A. and Vegetation in Reducing Summer Cooling Loads Stroud, D.A. (1988) The Flow Country. The in Residential Buildings. Journal of Climate Peatlands of Caithness and Sutherland. Nature and Applied Meteorology, 26(9), 1103 – 1116 Conservancy Council, Peterborough. 15 Bradshaw, A.D., Hunt, B. & Walmsley, T. 3 Stoneman, R. and Brooks, S. (1997). The Bog (1995) Trees in the Urban Landscape; Management Handbook. Stationery Office, Principles and Practice, E & F N Spon. London. 16 Leonard, R.E. & Parr, S.B. (1970) Trees as a 4 Holden, J., Chapman, P.J. and Labadz, J.C. Sound Barrier. Journal of Forestry, 68, 282 – (2004) Artificial drainage of peatlands: 283 hydrological and hydrochemical process and wetland restoration. Progress in Physical 17 Morales, D.J. (1980) The Contribution of Geography, 28, 1, 95-123. Trees to Residential Property Value. Journal of Arboriculture, 6(11), 305 – 308. 5 Heathwaite, A.L., Burt, T.P. and Trudgill, S.T. (1989). Runoff, sediment and solute delivery in agricultural drainage basins: a scale- dependent approach. 182. International Association of Science Publication.

6 Samson, A. (1996) Floods and sheep. Is there a link? Circulation, 49, 1-4.

7 DEFRA (2008) Future Water: The Government’s Water Strategy for England. HMSO.

8 Evans, M., Allott, T., Holden, J., Flitcroft, C. and Bonn, A. (Eds.) (2005) Understanding Gully Blocking in Deep Peat. Moors for the Future Report No. 4, Peak National Park, Bakewell.

9 Environment Agency (1997) R&D Update review of the impact of land use and management of flooding. Environment Agency.

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Flood Risk and Electricity Companies J.L. Whitehead ADAS UK Ltd, Gleadthorpe, Meden Vale, Mansfield, Nottinghamshire, NG20 9PF (Email: [email protected])

Abstract Introduction The 2007 summer flooding revealed how In the wettest May to July 2007 since records poorly protected vital public infrastructure is, began in 1766, areas experienced flooding with electricity supplies being particularly expected once in every 200 years. Many vulnerable. Some 75,000 people lost electricity locations were deluged with a month’s rainfall supply due to inundation of sub-stations. falling in a few hours. The wet May and early Consequently ENA (Energy Networks Agency) June meant that the ground was saturated and is now putting into place a review of the could no longer absorb rainfall. Extreme resilience of electricity substations to flooding. rainfall in late June and late July caused flash ADAS has been working closely with flooding where it fell and then accumulated in electricity companies to develop a methodology rivers to extend the impact to the floodplain. to assess the vulnerability of their assets. The These floods were different in scale and type purpose of ADAS’s work is therefore to from recent severe floods. In particular, a much determine whether sites have been correctly higher proportion of the flooding than normal identified as at risk from flooding and, if so, came from surface water rather than rivers. what levels are expected and hence what Surface water flooding was at its worst in cities protection is required. If in order to protect an such as Hull, but many villages and individual asset capital expenditure is required, ADAS properties also suffered across the country from will also provide a scientific justification for Bristol to Newcastle. Two-thirds of the the planned capital cost. properties flooded this summer were affected

Affected South Yorkshire & Gloucestershire & surrounding Region Humberside area

National Grid National Grid • 2 major substations • Walham switching station (Neepsend & Thorpe Marsh) required emergency flood defence reinforcement and pumping to avid loss due to flooding

CE Electric UK Yorkshire Central Networks Asset Electricity Distribution plc

• 4 major substations & 55 • 3 bulk supply point substations secondary substations (Warndon, Timberdine & Castle Meads

• Gelderd Road YEDL control • 400 distribution substations centre evacuated

• Damage to low voltage • Damage to low voltage network network cables cables 35,000 customers initially lost 40,000 customers supplied by supply – most supplies Castle Meads were cut off for up Customers quickly restored but some to 24 hours affected 9,000 customers were on a rota disconnection for several days Table 1. Number of transmission and distribution assets affected by flooding, summer 2007 (Pitt, 2007))

173 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 because drains and sewers were overwhelmed. If the switching-station had failed, there would River flooding was extensive in the rivers Don, have been a loss of electricity supply to some Severn and Thames, including their tributaries. 240,000 homes and businesses in the Gloucester area. Failure would have also The flooding revealed how poorly protected reduced the resilience in the supply of vital public infrastructure is, with electricity electricity supply to South Wales. However, and supplies being particularly vulnerable. National Grid was able to anticipate and Consequently ENA (Energy Networks Agency) mitigate the risk by creating a circuit bypass is now putting in place a review of the arrangement around Walham. National Grid has resilience of electricity substations to flooding. since installed a more permanent flood defence ADAS has been working closely with the system at Walham. electricity companies to develop a methodology to assess the vulnerability of their assets. Impact of Recent Flooding on Electricity Supply The loss of electricity has an enormous effect on people’s lives, as evidence in the Pitt Review highlights (Pitt, 2007). Some 75,000 people lost electricity supply due to inundation of sub-stations (Table 1). Gloucestershire was Plate 1. Flood barriers erected around Walham one of the particularly badly hit areas, with half switching station a million people threatened by power cuts, due to Walham sub-station flooding. The Castle Meads sub-station, which is part of the local distribution network, was shut Walham switching-station is part of the UK down and power to 40,000 homes was cut for high-voltage electricity transmission network 24 hours while temporary defences were and is owned and operated by National Grid. constructed and the site pumped out to facilitate The site supplies power to approximately re-commissioning. 500,000 customers across Gloucestershire and South Wales. It is built on raised ground next to The Department for Business the River Severn. National Grid had previously Enterprise and Regulatory Reform carried out risk assessment for flooding of the (BERR) Response to Flooding network. This had concluded that Walham Under the Electricity Safety, Quality and switching-station was at risk from events at Continuity Regulations 2002, electricity around a 1-in-1000 chance per year. A recent generators, distributors and meter operators are assessment carried out in 2005 put risk from required to construct, use and protect their flood events in the range 1-in-75 to 1-in-200 equipment to prevent interruption of supply so chance per year. far as reasonably practicable. Generators and On Sunday 22nd July 2007, water levels distributors are also required to prevent danger started to rise and threatened to inundate the due to the influx of water into any enclosed site. Overnight, 1km of temporary flood space arising from the installation or operation barriers were erected around the site by the of their equipment. Armed Forces, Environment Agency (EA), However the summer 2007 floods and those emergency services and National Grid. in Carlisle in 2005 have highlighted the Although the site was inundated, the barriers vulnerability of electricity substations to major (Plate 1), coupled with pumping, stopped the flood events (Table 2). More general concerns water from rising further when the water level over climate change and rising sea levels also peaked on 23rd July. During this time, the site did not fail and the essential service continued.

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Number of sites in flood zone (flood risk probability)

Significant (1 in 75) Moderate (1 in 75 – Low ( 1 in 200 or Total in all 3 Electricity Asset 1 in 200) fewer) zones Generation & distribution 2,215 2,263 3,818 8,423

Table 2. EA study showing infrastructure overlain on flood risk maps (adapted from Pitt, 2007) brings into question whether historic levels of services for customers in the North East (Plate protection from flooding will be adequate in the 2). However on the most part, many of the future. electricity companies have not yet taken any significant action to mitigate against flooding. As directed by the BERR the ENA are Where risk assessments have been carried out, currently coordinating and leading a review of they are often not adequate enough, as can be resilience to flooding. This review is being seen by the recent flooding at Walham taken forward within the existing Energy switching station. Emergencies Executive (E3) framework. It is recognised that an effective contribution from The next step for electricity companies is electricity supply industry is critically therefore to determine the flood risk of each of important to this review. Under this review the their assets. ADAS is currently assisting a ENA has asked the Distribution Companies and number of electricity companies with this task. National Grid to assess the individual risk level of primary substations within their ownership, Asset Flood Risk Assessments building on an earlier survey carried out in As part of the risk assessment, ADAS have 2005. been initially determining the proximity of assets to the floodplain. This assessment has Some Electricity companies have already been based on the Environment Agency’s flood taken action to mitigate against flooding. For risk maps (Figure 1). example the preparations that Yorkshire Electricity Distribution Ltd (YEDL) made as a However, the EA’s flood maps show the result of previous experience of extreme natural predicted extent of tidal and fluvial flooding in events have resulted in its infrastructure being the absence of flood defences. The EA more resistant to flooding risks. YEDL have maintains a large number of defences; therefore improved the defences at a number of its the maps show a much greater area subject to highest risk electricity sub-stations in response flood risk than is actually the case, as some are to the 2000 flood events. It is thought that this protected. The maps consequently give a investment helped to reduce the impact of the general indication of whether a site is in an area flooding on its assets and maintained essential that could be affected by river or coastal flooding. Not all sites shown in the floodplain are at the same risk of flooding, since many areas benefit from defences. To this extent, the classification of a site as at risk using the flood risk maps can be queried. The purpose of ADAS’s work is therefore to determine whether sites have been correctly identified as at risk from flooding and, if so, Plate 2. Blackburn Meadows electricity what levels are expected and hence what substation protected by flood defences protection is required. For all the sites in close

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Figure 1. Example of flood assessment sites compared to EA flood maps proximity or inside a floodplain ADAS is Once criticality and vulnerability are known, carrying out a comprehensive search into there are a number of choices to be made about available site levels. Where no site levels are how best to mitigate the risk of future flooding. available site surveys have been carried out to The first stage should be to consider whether establish an ordnance datum. Site levels then vulnerability is likely to be reduced as a result can be compared to either modelled or historic of an existing or future Environment Agency flood levels (Table 3), and an assessment of flood defence scheme. If not, electricity flood risk probability made. Probability is companies will need to consider a range of based on the following criteria: possible options, including: Significant ( <1 in 75) • Increasing resilience of the service or Moderate (1 in 75 to 1 in 200) asset. This may involve making the service Low (1 in 200 or fewer) more resilient by building additional Not significant network connections and/or making the asset

Site Ground Flood Return period (years) Origin of Flood Risk level level (m) flood level Probability (mAOD) 56.32 2 56.61 5 56.63 10 57.02 25 57.14 50 EA Strategic One 57.394 57.24 75 Low 57.28 100 River Model 57.42 200 (2007) 57.8 1000 57.52 100 + climate change 57.88 1000 + climate change 64.65 2 65.11 5 65.19 10 65.68 25 EA 66.02 50 Strategic Two 66.066 Moderate 66.18 75 River Model 66.36 100 (2007) 66.6 200 66.93 100 + climate change 66.6 1000 + climate change Table 3. ADAS site flood risk assessment

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more resistant to flooding through waterproofing key components or raising them out of harm’s way. • Improving the robustness of flood defences. This could include permanent defences for high-risk sites through to demountable or temporary defences for sites at medium risk. • Relocation of the asset. This would involve moving high-criticality assets out of the floodplain altogether and into a low-risk area.

The latter options require capital expenditure and provision must be made for this. ADAS will provide a scientific justification for the planned capital cost. Conclusion The methodology set out by ADAS has proven to be robust in helping electricity companies identify their assets that are at risk from flooding. It is hoped that this work will help in ensuring that electricity supply is uninterrupted during the increasing extreme storm events that are being predicted with future climate change. References Pitt, M. (2007) Learning lessons from the 2007 floods, an independent review by Sir Michael Pitt (Interim Report). http://www.cabinetoffice.gov.uk/upload/assets/ www.cabinetoffice.gov.uk/flooding_review/floo d_report_web.pdf (Accessed, January 2008)

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Impacts of 2007 Summer Floods on Agriculture Susan Twining1, Chris Procter1, Lucy Wilson1, Andy Frost1, Kate Phillips1, Tony Turner1, Don Tiffin1, Justin Emery1, Odelle Walker1, Simon Welch2 and Andy Wells2 1ADAS, Woodthorne, Wergs Road, Wolverhampton, WV6 8TQ 2The Arable Group (TAG), Manor Farm, Lower End, Daglingworth, Gloucs. GL7 7AH

Introduction total land area flooded, which was digitally In the summer of 2007, exceptional weather resulted captured into GIS software. The areas of in largely unprecedented summer floods in parts of flooded arable and grassland were calculated Yorkshire, East Midlands, West Midlands and the for each affected county using the Centre for South East. There were three main flood events. The Ecology and Hydrology (CEH) 25m resolution first event in late June caused flooding in Yorkshire Landcover data in conjunction with the flood and Humberside, and in the West Midlands in the extent maps. upper Severn and its tributaries. The second event followed in early July which caused repeat flooding Agricultural census data (at 1km2 resolution) in the upper Severn and its tributaries. The third were used to calculate the areas of broad crop event followed high rainfall on 20th July and mainly types within each 1km2 region that intersected affected the Rivers Severn, Avon, Wye and Severn the flood extents. The area of each crop type (in tributaries in Herefordshire, Worcestershire and hectares) that was affected by the floods within Gloucestershire, and the upper reaches of the River each of these squares was calculated by: Thames and its tributaries in Gloucestershire and Oxfordshire. Total area of crop type i x Flooded arable or grassland area

The floods caused widespread problems for Total arable or grassland area the agricultural industry including crop losses, delayed forage conservation for livestock, forced housing of livestock hence increased The total areas of the various crop types consumption of forage and concentrates, affected by the floods were then summed per increased disease in crops, delays in pesticide county. The maps and data were reviewed by applications, increased lodging in cereals and consultants with knowledge of local farming beans and saturated soils resulting in harvesting systems and adjusted accordingly, mainly to delays. account for greater area of potatoes in the river areas. The aims of this project were to determine the area of arable land and the types of crops Estimating the value of crop losses affected by the flooding, and to review the The value of the crop losses will depend on the likely impacts on the farming industry, extent and the duration of the flooding. In some including the financial implications of crop cases the flood water was not deep and receded losses. In addition, four case study farms were quickly, with minimal impact. Where the flood chosen to provide an insight into the effects the water was deeper or remained on the ground flooding had on certain types of farm business. for more than 7 days, or when sensitive crops such as potatoes and vegetables were affected, Methods the impact was greater. Where grassland was Calculating flooded crop areas used for grazing, provided livestock was moved from the land the losses were minimal, however Provisional maps of flood extents provided by where it was used for hay or silage, the losses the Environment Agency, along with remote of the crop and costs of reinstatement were sensing information, were used to identify the higher.

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Crop type S cenario 1 S cenario 2 S cenario 3 Low impact Medium impact High impact Cereal and 10% area with total loss 20% area with total loss 50% area with total loss oilseeds 90% with yield loss of 10% 80% with yield loss of 20% 50% with yield loss of 50% Straw 10% area with straw loss 20% area with straw loss 50% area with straw loss Potatoes 30% area with total yield loss 50% area with total yield loss 100% area with total yield loss 70% area with 50% yield loss 50% area with 50% yield loss Fodder crops Total loss Total loss Total loss Grazing No loss No loss No loss

Table 1. Low, medium and high flood impact scenarios for crop value estimates

Three scenarios were evaluated in order to Of the arable crops, wheat had the largest estimate the value of crop losses due to low, area affected, at an estimated 28% of the medium and high flood impacts (Table 1). flooded agricultural land area, which equates to approximately 0.7% of the total area of wheat Results in England in 2007. Potatoes accounted for only 2% of the flooded agricultural area but a Estimated area of crop losses relatively higher proportion of the English crop The area of flooded agricultural land flooded as area (1.0%). This is because potatoes are a percentage of the total agricultural land was preferentially grown on flood plains due to the less than 5% in all counties (Figure 1). The fertile soil and readily available irrigation in total area of flooded agricultural land was dry years. around 42,000ha. Approximately 63% of the flooded agricultural area was under arable and Estimated value of crop losses forage cropping and the remaining 37% was The estimated value of the total crops losses grassland. ranged from £7.7 million under Scenario 1 to £19.3 million under Scenario 3. Under Scenario 2, of the total £11.2 million of losses, 82% were in the arable sector, with only 18% in the grassland. The losses from the potato sector were estimated to be approximately £2.5 million for scenario 2, accounting for over 22% of the total value of losses. Combinable crop losses totaled £6.5 million, or 58% of the total. Losses from fodder and grassland crops were estimated at £2.3 million, or 20% of the total. The average loss per ha of flooded land ranged from £183/ha for Scenario 1 to £461/ha for Scenario 3. In reality, the loss per hectare will depend on the crop and the extent of the losses. Total potato losses could reach over £3000/ha, whilst hay and silage losses were estimated to be between £250 and £350/ha, and wheat typically £950/ha. Case studies Four case studies aimed to give an indication of Figure 1. Percentage of agricultural land affected by flood impacts on different types of farm. flooding by county.

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Case study 1 – Beef, sheep and arable farm Case study 3 – Dairy and arable farm This farm is 304ha in total and is part owned This farm is a large mixed unit of 625ha, with (69ha) and part tenanted (235ha), with 202ha of 115ha of grassland and 27ha of maize, permanent pasture and 102ha of arable. Part of supporting a dairy herd of 160 cows plus the land was flooded twice during the summer. followers; the remaining 483ha is arable. The The floods were relatively short-lived, and dairy unit and the majority of the grassland are there was sufficient notice to take mitigating on land adjacent to the river. The arable land is action such as moving livestock, however there mainly on higher ground. The summer floods were still significant direct and indirect remained on the land longer than normal winter consequences, both practical and financial. floods and caused more damage due to the stage of growth of the crops on the land. Direct impacts of the floods were mainly crop losses, with an estimated financial loss of The floodwater reached heights of 0.6-2.5m £18,461. Indirect impacts were associated with on 90% of grazing land and up to 1.8 m on 20- livestock having to be moved to higher ground, 60% of the arable land, leading to losses of with subsequent stress, overstocking and impact winter wheat, straw, oilseed rape, maize and on performance. This caused a delay in getting silage. As a result, additional and/or alternative lambs to market, which could mean losses of cattle feed was required, milk yield was £2 to £5 per head per week. The farmer had reduced, work load was increased and grassland sufficient capital reserves to fund the losses, but needed reseeding. This incurred financial losses cashflow was affected due to loss of grain and of approximately £50,000, but because of the delay in selling lambs. rise in cereal prices and the size of farm, the farm should still make a small profit. Case study 2 – Horticultural farm This farmer-owned co-operative has 600ha of Case study 4 – Arable farm with pig unit land bordering the river and supplies major The farm is a 485ha arable unit with supermarkets. Rainfall of 127 to 143 mm combinable crops and an indoor pig enterprise occurred on July 20/21, with flooding occurring in converted buildings. Of the 400ha of arable a day or two later. There was sufficient warning land and 62ha of grassland, 102ha and 42ha of rising water levels to mitigate damage in the respectively are on the flood plain. Year 2007 packhouse and offices, but little could be done crops were already damaged by prolonged to prevent fields flooding. Of major concern winter flooding and the April drought, reducing was loss of contracts for speciality crops whose the damage attributable to the summer floods. orders were not fulfilled in 2007. Water was still standing in lowest areas 1 month after the flooding; other areas were still Crop losses were substantial for french waterlogged or very wet. The majority of losses beans, courgettes and purple sprouting broccoli. were from arable crops, but the welfare and Orders for the supermarkets were severely financial threats to the pig enterprise were disrupted with limited or no produce available acute. for a short time. The costs incurred in growing the lost crops up to the point of the floods were A large proportion of the flood plain was £100,000 to £150,000. There are ongoing approximately 1.8m deep but parts were more implications for fields on the periphery of the than 3m. The flooding persisted widely for flooding where compaction has occurred and approximately 10-14 days. Harvestable crop excessive leaching of nutrients is leading to areas were not reduced by the flooding, but yield loss. Action will be taken to mitigate yields and quality of crops were poor and some future flooding, including a programme of ditch crops were unsaleable. The pig unit required work. emergency evacuation, but no stock was lost. Total financial loss was estimated at £58,678. In the longer term, the pig unit will become

180 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 unviable if flooding on this scale becomes a more regular occurrence. Similarly, for the arable enterprise, this experience will intensify the search for alternative economic activity on the flood plain fields. Acknowledgements This work was funded by Defra. Data and information from the Environment Agency and farmers who took part in the case studies is also gratefully acknowledged. Others who contributed local knowledge and information include National Farmers Union, Government Offices, Internal Drainage Boards, TAG, AICC and farmers.

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Sustainable Catchment Management Programme (Scamp) - Landscape Change and Flood Management Peter Worrall Technical Director. Penny Anderson Associates Limited

Abstract grazing animal numbers and the way they are managed on our moorlands, often combined The Sustainable Catchment Management with increased use of managed fire, has resulted Programme (SCaMP), operated by United in large-scale changes of vegetation types Utilities, is an innovative and large scale (Anderson & Yalden, 1981; Backshall, 1996). project that aims to improve upland catchment Some of these changes have been driven by quality in terms of raw drinking water, government policy and agricultural economics, hydrological functioning and nature others by management for red grouse (Lagopus conservation, and to ensure a sustainable future lagopus), but they have all had similar for the company’s agricultural tenants. The consequences in changing the way our upland programme hopes to demonstrate that, by catchments function in terms of discharging changing farming practices and land storm flows to the lowland reaches of our management in the upper catchments of river rivers. systems, the risks of declining water quality and flooding can be addressed. In addition, the Wide scale degradation of the blanket bog project is monitoring the impacts of land and moorland habitats of our upland management changes on upland habitats, their catchments has also been accelerated by the status and hydrometric functions. extensive excavation of drains (grips), grant- aided in the immediate post-war period and up United Utilities (UU) is the largest land to the 1970s. These activities have owner of the water companies, with 20,000ha fundamentally damaged the hydrological of upland water catchment, mostly in the Peak integrity of blanket bogs in particular. It was District, South Pennines, Bowland and the Lake initiated to increase dwarf shrub cover for District. Much of the upland element of these grouse and improve grazing for sheep, but is Estates (some 30%) has been designated as now contributing to increasing dissolved Sites of Special Scientific Interest (SSSIs) for organic carbons (DOCs) in streams from their dry dwarf shrub heath and blanket bog enhanced peat oxidation and decay, reduction in habitats. Many areas also lie in Special Areas of blanket bog wetness (Holden & Burt, 2003) and Conservation (SACs) for these habitats and vegetation dominated by species preferring Special Protection Areas (SPAs) for their breeding birds. However 11,367ha, are in an unfavourable condition according to the assessments made by Natural England, and the habitat degradation of this land is a key factor in declining hydrological services which these uplands have the potential to provide. The Peak District and South Pennines have been some of the most severely affected moorland catchments in the UK with habitat degradation commencing as long ago as the Gripped Moorland In Bowland fourteenth century. Significant increases in

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increased gullying, increased DOCs and greater vulnerability to further fires due to the drying of the surrounding peat. In combination, the history of upland management in these areas now presents a significant shift in semi-natural hydrological functions, a decline in water quality and the concomitant loss of valuable habitats, not to mention carbon losses which, if reversed, could save around 400,000 tonnes of carbon per year Incised grip in Bowland (Worrall et al., in press). drier conditions. Grips with sufficient runoff United Utilities, through SCaMP, is initiating generate considerable erosion, now cutting a programme of land management changes down into the underlying substrate below the which, amongst others, involves the catchment peat, and their major effect on streams has been scale reduction in grazing pressure in sensitive to increase their flashiness and risks of flooding blanket bog and moorland locations; the downstream. The density of grips across the catchment-wide blocking of grips, and the North Pennines and Yorkshire Dales is probably restoration of bare and eroded areas of peat. greater than any other part of England (Barrett, The impacts of these changes are being 1997) and potentially presents a significant monitored through water quality sampling at contributory factor to the flooding issue. the micro (site based) and macro (catchment) scales, combined with monitoring of water Changes in the character of vegetation in our levels in the peat bodies and runoff rates and uplands have also contributed to shifts in the volumes of catchment stream systems. The response of these catchments to rainfall events. response in the vegetation is being monitored in Some of these changes in vegetation have been parallel, in order to determine the brought about by burning the moorlands for red interdependence of the hydrological services grouse management. This has contributed to and habitat quality. increased heather dominance replacing other dwarf shrubs and blanket bog species on a The creation of extensively gripped widespread scale (Yallop, 2004). Moorland (drained) moorlands has two primary impacts wildfires in drought periods, if the root mat is on the hydrology of these catchments. In the destroyed, can result in the establishment of first place the grips act as storm discharge extensive bare ground, especially on blanket channels rapidly shedding runoff to receiving peat. Bare mineral ground might recolonise streams. In un-gripped catchments rainfall naturally, but erosion and gullying develop resides longer on the moor because the main where fragile peats are exposed, where soil pathway for rainfall into the streams is overland acidity has increased from air pollution and flow and not channelled flow in grips. This where early colonising bryophytes have been enables a greater proportion of the rainfall to lost. This is especially prevalent in the Peak reside longer on the moor and potentially District where over 33km2 of bare or partly infiltrate into the peat body. This process bare and eroding ground has been identified retains higher water tables in the peat, reduces (Phillips et al., 1981). Smaller areas occur in the oxidation of the peat mass (and consequent the South Pennines, the North York Moors generation of DOCs) and reduces the flashiness (Maltby et al., 1990), North Pennines, and on of the catchment stream system. Secondly, blanket bog in Wales (Yeo, 1997) and Scotland. extensive drainage through gripping has Bare peat leads to increased sediment into accelerated the loss of blanket bog species, rivers and reservoirs (Phillips et al., 1981), particularly Sphagnum species, which unlike

183 Flooding, Water and the Landscape - Journal of Practical Ecology and Conservation, Volume 7 No. 1 2008 heather dominated, peaty moorlands, respond to landscape and management of the uplands, with storm events by absorbing and holding the consequences on flood risk and flood rainfall in situ for longer (Lindsay, 1995). management. When the effects of gripping are allied with The act of grip blocking alone stimulates a the change and loss of vegetation cover through range of responses that potentially benefits over grazing and other environmental factors flood management. Once areas of gripped which accelerate erosion, the way in which our moorland are blocked, the rapid storm runoff upland catchments function in relation to storm characteristic of these areas shifts to a situation runoff is severely compromised. If, therefore, where the lag-time between the start of the hydrological equilibrium could be restored to rainfall and the peak flow in the stream upland catchments, an opportunity exists to extends. In this way the uplands would not modify the contribution upper catchments make generate such sudden flows downstream. to the risks of flooding in the lowlands. Initially, the peaks flows would remain the same because once the upper catchments are Limiting grazing levels on the moors has saturated runoff will be determined by possible economic consequences for tenant catchment length, steepness of slope and other farmers, and this is being addressed under environmental factors. However, over time, SCaMP through the rationalisation and with continued re-saturation and stabilisation of intensification of animal management the peat soils there could be an extension in the techniques. On the moor itself, reduced sheep growth of Sphagnum species. When this numbers will enable restoration of dwarf shrub becomes dominant in the catchment not only heath and blanket bog vegetation assemblages, will the lag time to peak flows become longer and when linked with the rise in water tables but the peaks themselves may become lower facilitated through the extensive blocking of because of the capacity of Sphagnum grips, sets in motion a radical change to the dominated systems to absorb and retain a greater proportion of rainfall events.

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Whilst this review does not suggest that such Wallage, Z.E., Holden, J. and McDonald, A.T. landscape scale changes to upper catchments (2006) Drain blocking: an effective treatment provide a solution to heightened flood risks for reducing dissolved organic carbon loss and downstream, it is, nevertheless, purported that water discolouration in a drained peatland. such changes will make a significant Science of the Total Environment, 367, 811-821. contribution to strategic and sustainable management of flooding in our lowland areas. Wheeler, B.D. and Shaw, S.C. (1995) Restoration of Damaged Peatlands. HMSO, London. References Worrall, F., Burt, T.P., Adamson, J.K., Reed, Anderson, P. and Yalden, D.W., (1981) M., Armstrong, A. and Evans, M.G. (in press). Increased sheep numbers and the loss of Predicting the Future Carbon Budget of Upland heather moorland in the Peak District. Peat Catchment. Climatic Change. Biological Conservation, 10, 195-214. Yallop, A. (2004) Control of Water Quality Backshall, J. (1996) A literature review of the from Upland Catchments. Moors for the Future. historical effects of burning and grazing on Moors for the Future workshop, October, 2004. blanket bog and wet heath. English Nature Research Report 172. Yeo, M. (1997) Blanket mire degradation in Wales. In: Tallis, J.H., Meade, R., and Hulme, Barrett, J. (1997) Moor gripping in the uplands. P.D. (Eds.) Blanket Mire Degradation, Causes, Enact, 5, 16-17. Consequences and Challenges. Proceedings of The Blanket Mire Degradation Conference held Brooks, S. and Stoneman, R. (1997) at the University of Manchester on 9-11 April Conserving Bogs. The Management Handbook. 1997. The Macaulay Land Use Research The Stationery Office, Edinburgh. Institute, Aberdeen. Pages 101-115. Evans, P., Ingles, I. and Chalk, E. (2001) Best practice in Upper Wharfedale. Enact, 9, 9-12. Holden, J. and Burt, T.P. (2003) Runoff production in blanket peat covered catchments. Water Resources Research, 39, 1191. Maltby, E., Legg, C.J. and Proctor, M.C.F. (1990) The ecology of severe moorland fire on the North York Moors: effects of the 1976 fires, and subsequent surface and vegetation development. Journal of Ecology, 78, 490–518. O’Brien, H. and Labadz, J. (2006) Moorland Management and discolouration of water supplies: evidence on a catchment scale? Moors for the Future Conference, Upland Ecosystem Services, November. Phillips, J., Yalden, D. and Tallis, J. (Eds.) (1981) Moorland Erosion Study. Phase 1 Report. Peak Park Joint Planning Board.

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