River Restoration Centre th 17 Annual Network Conference Planning, delivery and evaluation of our rivers: challenges and choices
26th – 27th April 2016 – The Imperial Hotel, Blackpool Kindly sponsored by:
Abstracts 2016
RIVER RESTORATION CENTRE 17TH ANNUAL NETWORK CONFERENCE
Planning, delivery and evaluation of our rivers: challenges and choices 26th and 27th April 2016 – The Imperial Hotel, Blackpool
PROGRAMME OF EVENTS
DAY 1: - - - TUESDAY 26TH APRIL - - -
REGISTRATION at Reception
9:00 90 mins NETWORKING & EARLY VIEWING POSTER SESSION in the Washington Suite
Session 1
Lancastrian Suite
River Restoration Centre introduction & welcome 10.30 15 mins Martin Janes (the River Restoration Centre)
Restoring beavers to Devon: Nature’s wetland architects 10.45 15 mins Derek Gow (Derek Gow Consultancy)
Working with natural processes to reduce flood risk and improve the 11.00 environment 15 mins Lydia Burgess-Gamble (The Environment Agency)
11.15 Discussion 10 mins
Instream restoration in action 11:25 15 mins Jackie Webley (Scottish Natural Heritage)
11:40 River weirs – remove or retain? 15 mins Matthew Hemsworth (JBA Consulting)
11:55 Delivering river restoration in Scotland: the next 12 years 15 mins SEPA
Delivery of river restoration as a mitigation to address WFD requirements 12:10 Sally German (ARUP) and David Holland (Salix) 15 mins
12:25 Discussion 15 mins
12:40 LUNCH 60 mins
RIVER RESTORATION CENTRE 17TH ANNUAL NETWORK CONFERENCE
Planning, delivery and evaluation of our rivers: challenges and choices 26th and 27th April 2016 – The Imperial Hotel, Blackpool
Session 2
Lancastrian Suite Louis Suite Princess Suite Urban River Restoration Partnering With Nature Ecological Monitoring
The restoration and regeneration of Working together to restore The Midlothian An ecohydrological approach to river Deptford Creek Esks restoration 13:40 15 mins Michael Forrester (London Borough of Clare Rodgers (Royal HaskoningDHV) and David Harper (Aquatic Ecosystem Services Lewisham) Tommy McDermott (River Forth Fisheries Ltd.) Trust & Trex Ecology)
Planning river restoration the Dutch way Removing and restoration of rock armour, Biotopes as design for restoration and 13:55 Ian Dennis (Royal HaskoningDHV) croys, and cars units for monitoring success 15 mins Kenneth Macdougall (EnviroCentre Ltd.) Ahmed Al Zankana (University of Leicester)
14:10 Discussion. Discussion. Discussion. 10 mins
RIVER RESTORATION CENTRE 17TH ANNUAL NETWORK CONFERENCE
Planning, delivery and evaluation of our rivers: challenges and choices 26th and 27th April 2016 – The Imperial Hotel, Blackpool
Session 2 – continued…
Improving habitat linkages in heavily Working with wood on the Wensum Using Beetles to measure riparian modified urban areas with Floating Ian Morrisey (Atkins Ltd.) and Marc Huband habitat quality 14:20 15 mins Riverbanks (Atkins Ltd.) Jon Webb (Natural England) Galen Fulford (Biomatrix Water Solutions Ltd., Land & Water Services Ltd.)
Public participation GIS for assessing Partnering with nature for sustainable river The Logie Burn: Results of three years 14:35 social values in urban rivers restoration of monitoring 15 mins Xavier Garcia (International University of Matthew Johnson (University of Nottingham) Stephen Addy (The James Hutton Catalonia) Institute)
14:50 Discussion. Discussion. Discussion. 10 mins
POSTER SESSION in the Washington Suite 15:00 45 mins with tea and coffee
RIVER RESTORATION CENTRE 17TH ANNUAL NETWORK CONFERENCE
Planning, delivery and evaluation of our rivers: challenges and choices 26th and 27th April 2016 – The Imperial Hotel, Blackpool
Session 3
Lancastrian Suite Louis Suite Princess Suite
Addressing Multiple Objectives Beaver Reintroduction Understanding sediments
Balancing flow – balancing opinion Restoring beavers to Devon: Achieving measures for heavily modified Jane Moon (Black & Veatch) Understanding their impacts water bodies using sediment 15:45 Mark Elliott (Devon Wildlife Trust) management 15 mins Katy Kemble (Jacobs) & Matthew Buckley (United Utilities)
Conflict of interest in river restoration: a Quantifying the multiple benefits of Weir pools and hydropower: methods to 16:00 15 mins county council perspective beaver activity across catchment scales assess impacts Jessica Dippie (Buckinghamshire County Council) Richard Brazier (University of Exeter) Simon Palmer (APEM Ltd.)
River restoration pitfalls and successes from Bringing beavers back: how will we Rapid biodiversity gains through concept to monitoring manage this species? naturalisation: process based success 16:15 15 mins Jenny Mant (Ricardo AEA) & Martin Janes (River Roisin Campbell-Parker (Royal Zoological stories Restoration Centre) Society of Scotland) George Heritage (AECOM)
16:30 Discussion. Discussion. Discussion. 15 mins
16:45 SHORT BREAK TO MOVE TO FINAL JOINT SESSION 10 mins
RIVER RESTORATION CENTRE 17 TH ANNUAL NETWORK CONFERENCE
Planning, delivery and evaluation of our rivers: Challenges and choices 26th and 27th April 2016 – The Imperial Hotel, Blackpool Session 4
Lancastrian Suite
Keynote Address Positioning River Restoration for 2030: lessons from the past and challenges for the future 16:55 Geoff Petts (Vice Chancellor and President, University of 25 mins Westminster; President of the British Hydrological Society and Editor-in-Chief of River Research and Applications)
17:20 Discussion (Keynote and General) 20 mins
Poster competition prizes, final announcements and close 17:40 15 mins Martin Janes (RRC)
17:55 END OF DAY 1
19:30 – PRE-DINNER DRINKS RECEPTION Washington Suite &
20:00 – UK RIVER PRIZE AWARDS DINNER Lancastrian Suite
RIVER RESTORATION CENTRE 17 TH ANNUAL NETWORK CONFERENCE
Planning, delivery and evaluation of our rivers: Challenges and choices 26th and 27th April 2016 – The Imperial Hotel, Blackpool
DAY 2: - - - WEDNESDAY 27TH APRIL - - - Registration Opens at 8:30am
Session 5
3 hours CHOICE OF SITE VISIT OR WORKSHOP 9:00 30 mins
Workshop A: Workshop B: Natural Flood Management: Tools to Help How to Make the Most of Your Monitoring and Maximise Benefit and Reduce Risk Project Appraisal
Workshop C: Workshop D: Demonstrating the Value of Ecosystem Services Building Technical River Restoration Capacity for Decision Making
Site Visit: Workshop E: The Wyre Riparian Restoration Dealing with sediment in respect to Initiative in-channel structures
12:30 LUNCH 65 mins
RIVER RESTORATION CENTRE 17TH ANNUAL NETWORK CONFERENCE
Planning, delivery and evaluation of our rivers: Challenges and choices 26th and 27th April 2016 – The Imperial Hotel, Blackpool
Session 6 Lancastrian Suite Louis Suite Princess Suite Barrier Removal Shaping Our Rivers Modelling: Tools and Techniques
Provision of fish passage in The Worfe The importance of reference state and the Integrated dynamic analysis of modified Catchment assessment of potential for geomorphic channels: dealing with constraints in urban 13:35 15 mins Iain Stewart-Russon (APEM Limited) work areas Hamish Moir (Cbec eco-engineering LTD) Ian Bentley (AECOM)
Innovative fish passage design on an A method for definining potential Habitat modelling: a useful design, East Lancs river locations for WFD and flood risk investigation and appraisal tool 13:50 15 mins Adam Walmsley (Ribble Rivers Trust) restoration in a large catchment Dave Mould (JBA Consulting) Katy Kemble (Jacobs) and Sera Roberts (Jacobs)
Lessons learned at a Norfolk mill Balancing risk and reward: a call for a Hydraulic modelling requirements for river 14:05 Jonathan Whitmore (slightly) more cavalier approach to restoration: methods for minimizing (not 15 mins (JBA Consulting) restoration just flood) risk George Heritage (AECOM) Eric Gillies (Cbec eco-engineering Ltd)
14.20 Discussion. Discussion. Discussion. 15 mins
14.35 10 mins SHORT BREAK TO MOVE TO FINAL JOINT SESSION
RIVER RESTORATION CENTRE 17 TH ANNUAL NETWORK CONFERENCE
Planning, delivery and evaluation of our rivers: Challenges and choices 26th and 27th April 2016 – The Imperial Hotel, Blackpool
Session 7
Lancastrian Suite
Delivering Severn Trent Water’s fair share of the WFD 14:45 15 mins Mike Streetly (ESI)
15:00 How we achieved good ecological potential 15 mins Bella Davies (South East Rivers Trust) and Dave Webb (Environment Agency)
15:15 River restoration – Priorities for action 15 mins River Restoration Centre
15:30 Discussion and Close. 15 mins
15:45 END OF CONFERENCE
REFRESHMENTS
tea and coffee available
Day 1: Tuesday 26th April Session 1: Lancastrian Suite RESTORING BEAVERS TO DEVON: NATURE’S WETLAND ARCHITECTS D. GOW1 Additional authors 2 3 4 R. CAMPBELL-PALMER , M. ELLIOT , G. SCHWAB 1 Derek Gow Consultancy, 2 Royal Zoological Society of Scotland, 3 Devon Wildlife Trust, 4 Bund Naturschutz in Bayern e.V
Beavers were hunted as a valuable international commercial trade item across Europe and North America. It is generally presumed they became extinct in England in the 1100s but evidence from historical writings suggests small population may have been present at least into the 1600s.
Beaver created landscapes across Europe provide habitats for a range of species including large herbivores, small mammals, birds, fish, amphibians and reptiles. Along with habitat creation, beavers and their activities provide a range of ecosystem services which are not only sustainable but free! Such dynamic systems naturally regulate water flow, trap nutrients and silt, retain water, purify water and alleviate flooding – the importance of which are now widely recognised e.g. Wetland Biodiversity Strategy for Britain. Many of these functions are being artificially imposed in river systems through significant resource investment. In the absence of beavers our own efforts to restore wetlands will be forever compromised by an ever increasing requirement for human management and intervention.
The Pitt Review (2007), commissioned by the UK government in response to the summer floods of 2007, stated that ‘flood risk cannot be managed by simply building ever bigger hard defences. Softer approaches, such as flood storage… provision of storage…. or enhanced wetlands; and slowing flows… restoring smaller watercourses to a more natural alignment’. Beavers offer a tangible solution if we are prepared to tolerate their presence.
Across Europe the use of beavers in river restoration projects is well documented as will be discussed further here. Although negative costs of beaver presence have been widely cited it is important to put these into perspective. Time and again, the impact of beavers on agriculture and commercial forestry, especially in relation to common species such as deer and rabbits, has been demonstrated to be insignificant. In lower Bavaria the annual cost of beaver activity to the public purse has been calculated as equating to less than the average cost of damage by other game species.
There is increasing impetus to see the restoration of this extensively studied species. Britain is one of the last states in Europe to fully reintroduce this species. Co-operation between various stakeholders is vital, but significant barriers in terms of perception still remain.
WORKING WITH NATURAL PROCESSES TO REDUCE FLOOD RISK AND IMPROVE THE ENVIRONMENT L. BURGESS-GAMBLE1 M. ROSS1 1 The Environment Agency
Flooding can occur from many different sources. We saw this in winter 2013-2014 when the storm surge caused flooding on the east coast, there was widespread river flooding across many counties, chalk springs started to flow leading to groundwater flooding and in many places surface water flooding was caused by short intense rainstorms that overwhelmed drains and sewers.
There are many ways to reduce the impact of a flood. We can build walls and defences to provide a barrier against flood water; install property-level protection such as flood boards across doorways; maintain the watercourse channel differently; deploy temporary barriers; provide flood warnings and develop evacuation plans. Alongside these traditional forms of flood risk management we are starting to see greater use of natural processes to reduce flooding.
Working with natural processes involves restoring catchments, rivers, floodplain and coasts to their natural functions. On the coast, this might mean moving the defences inland and creating a new salt marsh on the seaward side. This marshland should absorb wave energy and reduce the amount of water that could overtop the defences. It can also provide a rich habitat for wildlife. The Steart and Medmerry Managed Realignment Schemes are brilliant examples of this. On rivers it can include restoring rivers and floodplains, creating wetlands, capturing runoff in the uplands (see Holnicote and Moors for the future) and in low-lying ponds (see Belford), and planting trees (see Pickering and Stroud). All of these measures promote infiltration, help store water and slow down the rate at which it enters river systems.
Engineering with nature can help to reduce flooding. It can also provide other benefits to people and the environment such as improving water quality, creating new recreation opportunities and helping make space for water. This in turn makes our rivers and coasts more resilient and able to adapt to climate change.
One big challenge for us if we are to work more with nature is how we demonstrate the flood risk benefits of these measures. We like to be able to show with confidence how our schemes function to reduce the risk of flooding to people and property. However, these sorts of measures can be hard to model, also how they will perform in a flood can be uncertain and hard to predict.
A recent Ciria report identified that land management measures (such as ponds and runoff control measures) are only effective at reducing flood risk in small floods in small catchments. This shouldn't be interpreted that working with natural processes is not worthwhile. In fact, this evidence shows that relatively simple and cheap measures can help reduce flood risk in small catchments.
The Ciria report also only refers to a small suite of working with natural processes measures (mainly land management measures). So the outcomes of this report cannot be applied carte blanche to all working with natural processes measures. There are other techniques which are effective at reducing flood risk in larger catchments and on the coast.
To help bust these myths we are planning some research projects which will develop a working with natural processes evidence directory and a suite of tools to help us identify potential measures which could be used to help reduce flood risk.
Working with natural processes will not resolve all of our flooding problems. However, in some places, they may be the only viable means of managing risk. In other locations, such as Lustrum Beck, they can be used to compliment rather than replace traditional flood risk schemes, helping bolster the performance of our flood defences.
INSTREAM RESTORATION IN ACTION J. WEBLEY1 I. SIME1 Additional authors 2 3 4 5 L. WILKIE , M. BILSBY , M. HALLIDAY S. COOKSLEY 1 Scottish Natural Heritage, 2 Rivers and Fisheries Trusts of Scotland, 3 Dee District Salmon Fisheries Board, 4 Esk District Salmon Fisheries Board, 5 James Hutton Institute
‘Pearls in Peril’ is a LIFE+ NATURE best practice project working to safeguard important populations of freshwater pearl mussel (Margaritifera margaritifera) in Great Britain. A wide range of conservation measures is being implemented in 21 key river systems. The measures aim to: restore the habitat of freshwater pearl mussel and salmonids, secure the long term survival of existing freshwater pearl mussel populations, and communicate with local, national and international audiences to raise awareness of freshwater pearl mussel conservation. The project is co-funded by 22 organisations across Scotland, England and Wales and runs for four years, ending in September 2016.
The primary objective of the project is to RESTORE habitat to benefit both mussels and salmonids (Atlantic salmon (Salmo salar) and trout (Salmo trutta)), on which the pearl mussel lifecycle depends. In-stream restoration work has increased the length of watercourse that supports available spawning and juvenile mussel habitat through reinstating a more natural flow and sediment deposition regime.
Over the past three years PIP, which is a partnership project, has restored over 4km of in-stream habitat on the Rivers Dee and South Esk in Scotland and on the Afon Eden in Wales. The process has presented a number of key challenges covering stakeholder engagement, regulation and practical and technical issues associated with physical works. Examples of these will be demonstrated through two case studies:
Case Study 1 – River Dee removal and reduction of ‘croys’ (wedge shaped structures used as fishing platforms and constructed with boulders taken from the riverbed) and removal of artificial bank protection (‘Car Bank’). Boulders have been replaced within the channel restoring riverbed habitat. Bank protection has been removed and the bank re-profiled to re-connect the river with its flood plain. A range of challenges were presented across the sites particularly associated with stakeholder engagement, management agreements and regulation.
Case Study 2 – River South Esk removal of 873m of boulder bank protection and re-opening of paleochannels restoring natural river processes. This site presented challenging practical and technical issues associated with landscape, land use, access and archaeology located within a Special Area of Conservation.
Managing a variety of stakeholders with a range of objectives to deliver restoration works with a value in excess of £500k has been challenging. The delivery of the in-stream restoration has been realised primarily due to effective partnership working derived from a clear project structure and delivery plan.
PIP is implementing before and after monitoring of the restoration sites, with monitoring programmes established at the project inception. In addition, the multiple benefits of this work are now being considered through the preparation of an Ecosystem Services and Socio-economic Assessment. These measures are fundamental to building the evidence base that will facilitate future river restoration projects.
RIVER WEIRS – REMOVE OR RETAIN? M. HEMSWORTH1 1 JBA Consulting
The Environment Agency, CIRIA and the RRC have recognised the need to update the current version of the Weirs Guide in light of changes to legislation, policy and environmental drivers in the UK.
It is aimed at a wide readership with responsibilities or interests in the design, operation, maintenance, modification and removal of river and canal weirs. The target audience includes regulatory authorities, professionals and stakeholders, clients, engineering consultants and contractors, architects, navigation authorities, heritage bodies, owners of mills, historic buildings or landscapes, weir preservation societies, abstraction licence holders, hydropower promoters, land owners, land agents and farmers. It is also applicable to fisheries owners, angling clubs and recreation bodies.
When planning works that are likely to involve the weir structure, options should include those that work with natural processes or perform the functions of a weir without compromising other interests. Options should have regard to the changes that may take place during the design life of the weir such as climate, land use or land management change, and consider how to deal with those changes: whether to select options that are sufficiently robust to accommodate a range of future scenarios, flexible to allow alteration to new circumstances in the future, or whether to delay decisions that would be difficult to change.
An important question to ask is whether a weir structure is necessary or whether an alternative can be adopted, to improve compliance with the Water Framework Directive.
The decision making processes associated with weir removal / modification / lowering / new build / maintenance will be covered in terms of the necessary assessments to determine river response, within the context of the WFD and acknowledging wider river users who will have interest in the structure. Case studies will be used to demonstrate key principles including the Irwell catchment and examples provided by the RRC.
The new guide brings together existing information and sign-posts other relevant material that is available to all river managers, river users and stakeholders. This presentation summarises the revised CIRIA Weirs Guide, including detail on decision making processes and the numerous elements to consider, demonstrating that a ‘one size fits all’ approach to evaluating outcomes does not apply to UK weirs.
DELIVERING RIVER RESTORATION IN SCOTLAND: THE NEXT 12 YEARS R. RICHARDSON1, S. MCCONNELL1 Additional authors R. HARDING-HILL1, R. JEFFERIES1 1 Scottish Environment Protection Agency
The second river basin management plans for Scotland set out an ambitious programme of river restoration for the next 12 years. They aim to restore over 3,000km of river to good ecological health and remove over 300 barriers to fish migration. This presentation sets out the current condition of Scotland’s rivers and how we plan to address the main pressures affecting them. Delivery of river restoration on this scale will require a step-change in effort, innovative solutions and a new approach to partnership working between public bodies, NGOs and land managers. The presentation will set out how we intend to achieve this by building on the success of the Water Environment Fund, pilot catchments and other initiatives to develop new partnerships, secure funding and deliver multiple benefits. Catchment based case studies will be used to illustrate the approach and risks to delivery will be discussed.
DELIVERY OF RIVER RESTORATION AS A MITIGATION TO ADDRESS WFD REQUIREMENTS S. GERMAN1 D. HOLLAND2 Additional authors I. LEXARTZA-ARTZA1, J. BAXTER3 1 ARUP, 2 Salix, 3 Yorkshire Water Services
Rivers that have had their flows reduced or their sedimentary regime disrupted by human intervention can struggle to re-establish the processes that support a diverse and functioning morphological and ecological system. Improving the likelihood that restoration interventions will be successful requires a good understanding of the processes acting on the system under the modified regime. If the design of the new channel geomorphology, and its associated features, is based on such an understanding, this will result in both improved functionality and the development of a more natural and diverse ecological system. Appropriate interpretation and implementation of the design intent on the ground requires close collaboration between designer and contractor. Case studies have been used to demonstrate a range of approaches to establishing improved channel morphologies that better suit the modified flow and sedimentary regimes in these rivers. These case studies are primarily focused on addressing WFD objectives. The paper discusses design approaches as well as the practicalities and constraints associated with delivering such schemes on the ground.
Session 2: Parallel Sessions Lancastrian Suite: Urban River Restoration THE RESTORATION AND REGENERATION OF DEPTFORD CREEK M. FORRESTER1 P. CHAPMAN1 1 London Borough of Lewisham
Deptford Creek is unique to London, and forms the divide between two boroughs (Lewisham and Royal Greenwich). The Council’s Planning Service has consistently ensured that regeneration is comprehensively brought forward, always placing the Creek at the heart of a development scheme.
The presentation will focus around the Council’s vision for regeneration and approach to working with interested stakeholders; how it promotes and achieves real place-making benefits for the benefit of the community and ecology. Working from a strong policy basis and clear vision the Planning Service has been able to consistently promote the aspirations for Deptford Creek. The Creekside Charette (2008) was a design-led document pulled together from interested stakeholders to shape the development of the Creek.
The approved redevelopment of Kent Wharf provides public access to the Creek for the first time in over 100 years. The 0.4 hectare site provides 143 homes, 1400 m2 of artist studios, a river walkway and real engagement with the Creek. The design is influenced from the Charette.
The redevelopment of the Faircharm Creative Quarter (winner of a 2014 Housing Design Award) provides ecological landscaping, repairs and renewal of the river defence walls in addition to 148 homes and over 4000 m2 of workspace.
The Trinity Laban Conservatoire of Music and Dance (2003 RIBA Sterling Prize winner) saw a former Council Depot transformed to a statement building, landscaping which again provides access to the Creek. These developments together have and will continue to transform historically neglected industrial land, turning Deptford Creek into vibrant and successful location.
The Planning Service has been able through consistent communication with local stakeholders (residents, and the Creekside Discovery Centre) to ensure that developers understand the meaning of a Creek to ensure that development proposals are designed from a relevant context (i.e. avoiding comparisons with canal development).
The Council has been able to ensure that all sites are master-planned (regardless of land ownership) to confirm that development is achieved in a comprehensive manner and that ambitions, such as a continuous Creek public walk, are embedded into design strategies. We encourage master-plans to have ‘buy in’ from local stakeholders to ensure they are deliverable. This has been a successful approach.
We ensure that developers approach the Environment Agency and the Port of London Authority at pre-planning stages to secure the necessary upgrades to flood defences, ensuring that these are designed into wider public realm and landscaping schemes. These in turn are factored into scheme viability – as all schemes must be ‘buildable’ without compromise.
The result of this collaborative approach is that planning policies, local needs and regeneration are brought forward collectively to ensure that development is genuinely place-making and enhances the special and unique qualities of Deptford Creek.
PLANNING RIVER RESTORATION THE DUTCH WAY I.A. DENNIS1, G.J. MEULEPAS1 1 Royal HaskoningDHV,
The Dutch government’s ambitious Room for the River project delivered a coherent set of measures to improve flood resilience and deliver environmental and societal benefits at 30 sites across The Netherlands. Royal HaskoningDHV played a significant role in the planning and implementation of the Room for the River programme, and were directly responsible for the delivery of almost half of the total expenditure of €2.2 billion.
Our team identified and planned restoration options, undertook environmental studies and impact assessments, designed schemes and supervised construction. Using our Nature Driven Design approach, we produced sustainable designs that work with natural river processes to deliver significant improvements for flood risk management, biodiversity, WFD compliance and public amenity.
One of the key components of the Room for the River programme was delivered in the city of Nijmegen, where the morphology of the river constricted flow conveyance and encouraged flooding. A secondary flood relief channel was created, supporting natural river habitats and recreating the chain of naturally-functioning green floodplains along the river. The new island that was created between the two river channels was used as a focus for waterfront development, with an important role in the future development of Nijmegen.
This presentation will focus on the way in which the project was planned and delivered, with particular attention to the lessons that were learned and how these could be applied to facilitate ambitious river restoration projects in the UK. Altering a river system on the scale of the Room for the River programme was unprecedented, and was a technical challenge with often large social impacts. Technically, the impact assessment of the measures on the river system was an enormous task entailing a number of risks. We successfully managed these risks through robust planning, a detailed understanding of the context and strategic processes in which the project fits, and robust Nature Driven Design supported by detailed geomorphological and hydraulic modelling.
Developing an understanding of the aims and concerns of a wide range of stakeholders and ensuring that they were reflected in the developing designs was vital to the success of the project. In particular, we worked with all levels of the community, from public administrators to landowners and the general public, to create a sense of ownership for the project and foster the idea that all groups were working together for a common goal. We also found that facilitating a direct line of communication between decision makers and project funders, public stakeholders and the design team was important to ensure that risks were overcome without delaying the project programme, and that the final results were supported by all stakeholder groups.
IMPROVING HABITAT LINKAGES IN HEAVILY MODIFIED URBAN AREAS WITH FLOATING RIVERBANKS G.Y. FULFORD1 1 Biomatrix Water Solutions Ltd and Land & Water Services Ltd
This presentation will address the application of Floating River Banks as a technique to improve ecological potential and provide habitat linkages and connectivity in urban areas.
Achieving WFD objectives in the context of urban environments can be challenging, particularly in areas where riverbanks are re-enforced with vertical concrete and sheet pile riverbanks. Additionally, habitat corridors through urban areas can become fragmented, due to floodwalls and surrounding infrastructure.
Project case studies will be explored in order to highlight some of the advantages of successfully incorporating urban green infrastructure, specifically where catchment hosts chose Floating Riverbanks for installation on the Lea Navigation. These project case studies include a series of three floating riverbanks and were assembled from 22 interlocking floating ecosystem components.
The presentation will discuss, in detail, the practical application of Floating Riverbank techniques for these projects. The presentation will also address the practical issues encountered throughout the case studies, including designing the river restoration project to effectively manage water level fluctuations in excess of 1.5 meters.
Additional practical issues will be discussed, such as the measures required to protect young plants from excessive waterfowl grazing, as well as providing areas for immediate waterfowl access for preening and nesting.
The presentation will also address how fluctuation in water velocity and erosive forces are calculated, taking in to account form and friction drag to ensure a secure and long lasting installation.
Aspects including appropriate site selection will be covered to provide the key information that catchment hosts and waterway managers require to evaluate locations where Floating Riverbanks can offer a solution to improve ecological potential, as well as provide habitat linkages through the urban environment.
The presentation will include detailed before and after photographic documentation, as well as underwater photography.
It will cover the types of species which can be installed, as well as the increase in macrophyte biodiversity and subsurface and surface habitat types. Additionally, it will cover areas that can be established and quantified from projects utilising Floating River Banks.
The presentation will provide upstream to downstream water quality monitoring results and will present case studies demonstrating measurable impacts on specific water quality parameters including coliforms, BOD, COD, NH3 and P reduction.
PUBLIC PARTICIPATION GIS FOR ASSESSING SOCIAL VALUES IN URBAN RIVERS X. GARCIA1, M. BENAGES1, P. VALL1 1 International University of Catalonia
Urban planners worldwide are focusing their attention on rehabilitating urban river corridors as part of the system of open spaces and in response to a growing social demand (Asakawa et al. 2004, Özgüner et al. 2012). In this context, urban river corridors, beyond their high ecological value as habitats, provide valuable cultural ecosystem services (Brauman et al. 2007). Cultural ecosystem services are all those that provide human enjoyment and a positive influence on human psychological and physical health (spiritual and religious, recreation and ecotourism, aesthetic, inspirational, educational, place attachment and cultural heritage) (MEA 2005). However, the most general characteristic of cultural ecosystem services is intangibility, which means they are commonly overlooked in biophysical or economic based assessments, and therefore often disregarded in decision-making processes against those ecosystem services more easily quantifiable (Gee and Burkhard 2010).
The objective of this study is to evaluate local stakeholders’ knowledge of the spatial assessment of cultural services, negative values and places that require rehabilitation actions, associated to riparian urban landscapes. To achieve this, a public participation GIS (PPGIS) method has been applied to map local empirical knowledge of cultural services and negative values (water scarcity, pollution, crime, flood risk, among others) in order to obtain a more informational assessment of the potential trade- offs that may affect any rehabilitation action in a given location (Brown et al., 2012). Furthermore, this cartographic tool has allowed us to identify strategic spots for rehabilitation actions according to the local stakeholders’ priorities. The study area selected is the Caldes Stream in the Besòs River Basin (Catalonia, Spain). Along its 22 kilometres of riverfront, it connects an urban system of approximately 60,000 inhabitants and has become a significant place in the everyday life of many riverside residents, as well as many people from the metropolitan region, who at weekends engage in leisure activities along its embankments. The relevance of this study area, 25 kilometres away from Barcelona, lies in the continuity of low-density residential and industrial fabrics along the watercourse. During the data collection, 35 stakeholders of the Caldes Stream were interviewed and asked to map cultural services, negative values and locations perceived to require rehabilitation actions.
Preliminary GIS analysis of the data obtained shows that mapped cultural services are not scattered randomly across the riparian landscape, but rather present significantly different intensity and diversity patterns. As expected, the participants’ most commonly mentioned, and thus more valued, cultural services are recreational and aesthetic. Flood risk perception, and water quantity and quality issues are the most frequently identified negative social values. The locations perceived to require rehabilitation actions most often coincide with negative value hot-spots, although some of them often correspond to areas with less diversity of cultural services. The PPGIS approach allows us to effectively represent intangible and context dependent cultural services from stakeholders’ knowledge, often not considered in the rehabilitation decision-making process. This spatially explicit information on cultural ecosystem services, and other social values, provides a valuable basis for the development of sustainable river rehabilitation strategies.
References: Asakawa, S.; Yoshida, K.; Yabe, K. (2004). Perceptions of urban stream corridors within the greenway system of Sapporo, Japan. Landscape and urban planning, 68, 167–182.
Brauman, K. A.; Daily, G. C.; Duarte, T. K. E.; Mooney, H. A. (2007). The nature and value of ecosystem services: an overview highlighting hydrologic services. Annual Review of Environment and Resources, 32, 67–98. Brown, G.; Montag, J. M.; Lyon, K. (2012). Public participation GIS: a method for identifying ecosystem services. Society & natural resources, 25(7), 633-651. Gee, K.; Burkhard. B. (2010). Cultural ecosystem services in the context of offshore wind farming: A case study from the west coast of Schleswig-Holstein. Ecological Complexity, 7, 349-358. MEA - Millennium Ecosystem Assessment (2005). Ecosystems and human well-being, Washington, DC: Island Press. Özgüner, H.; Eraslan, S.; Yilmaz, S. (2012). Public perception of landscape restoration along a degraded urban streamside. Land Degradation & Development, 23, 24–33.
Louis Suite: Partnering With Nature WORKING TOGETHER TO RESTORE THE MIDLOTHIAN ESKS C. RODGERS1, T. MCDERMOTT2 Additional authors C. AGNEW1, I. DENNIS1, A.BAKER3 1 Royal HaskoningDHV, 2 River Forth Fisheries Trust & Trex Ecology, 3 River Forth Fisheries Trust
The North Esk and South Esk rivers in the Midlothian region near Edinburgh have a long history of industrial activity. A series of weir structures, formerly used to power mills, now act as barriers to fish movement and sediment transport. In November 2014, the River Forth Fisheries Trust was granted funding to deliver and manage the mitigation of barriers along the Midlothian Esks, through SEPA’s Water Environment Fund (WEF).
The first phase of this work aimed to understand the issues with fish passage and sediment movement, and prioritise the available options for mitigation. Over 40 barriers that severely restrict the distribution of native fish species are recorded on SEPA’s national database for the Esk catchment, with more identified during a systematic walkover of the main river channels and major tributaries carried out by the Trust. The Trust appointed Royal HaskoningDHV to undertake a detailed investigation for thirteen of these barriers, prioritised by their impassability for fish.
The partial collapse of one barrier in December 2014 revealed an unexpectedly large volume of gravel trapped behind this structure. Additional analysis undertaken by Royal HaskoningDHV indicated that a significant volume of sediment was likely to be trapped behind these thirteen barriers. This information was vital in informing how to tackle barriers in this catchment, as the removal of one structure could lead to greater accumulation of sediment and increased bank erosion at the next barrier in place downstream.
Royal HaskoningDHV’s river restoration team worked with the Trust to identify and engage directly with over 50 local residents, anglers and representatives from local organisations at public meetings across the catchment throughout May and July 2015. The combination of barrier management expertise from specialist consultants and local knowledge from Trust staff was particularly effective in ensuring that the full range of stakeholders’ questions and concerns could be addressed at these events.
At the end of this scoping phase, Royal HaskoningDHV provided the Trust and SEPA with a report setting out the preferred list of options for each of the thirteen barriers, along with approximate costs and recommendations to support the next phase of work. Options to remove barriers were preferred where feasible, as this would provide the fullest restoration of ecological and geomorphological processes, with priority given to downstream barriers working up towards the headwaters.
Over the course of this project, collaboration between the River Forth Fisheries Trust, Royal HaskoningDHV and SEPA has demonstrated how working in partnership can provide a cost-effective means of undertaking a thorough catchment-scale appraisal, to deliver site-specific solutions that are robust and sustainable in the long term. This has led to agreement from SEPA for funding for the next phase of work, starting with design of the preferred options for the two most downstream barriers in the system, to enable fish and other species to access the excellent habitat currently available upstream.
References: Rodgers C and McDermott T (2015) Salmon, Stakeholders and Sediment: River Restoration on the Midlothian Esks. Published in CIWEM’s The Environment Magazine, October 2015, Vol 20, p24-26. River Forth Fisheries Trust (2016) Midlothian Esks Restoration Project. [Online]. Accessed from: http://www.fishforth.co.uk/rfft/midlothian-esks-restoration-project/
REMOVING AND RESTORATION OF ROCK ARMOUR, CROYS AND CARS K.A. MACDOUGALL1 Additional authors H. ROBSON1, M. NICHOLS1, L. WILKIE2, J. WEBLEY3 1 EnviroCentre Ltd, 2 Rivers and Fisheries Trusts of Scotland, 3 Scottish Natural Heritage
During the summer of 2015, four river restoration projects were undertaken by the EU LIFE Pearls in Peril project. The works were undertaken on the River Dee and River South Esk in north east Scotland, both designated Special Areas of Conservation for species including Atlantic Salmon (Salmo salar) and freshwater pearl mussel (Margaritifera margaritifera). On the upper River South Esk, nearly 0.9 km of large rock armour bank protection was removed and banks restored, along with reconnection of relict channels. During these works, one of the largest floods in recent memory swept through the works.
There were three projects on the main stem of the River Dee. These included two projects for the removal of 25 croys, bank restoration and stabilisation between Aboyne and Banchory. The works were undertaken in August when more favourable river levels were anticipated, however high flows persisted throughout this period. Some of the pairs of croys at Banchory reduced the river to 30% of the natural width, constructed from several hundreds of tonnes of rock, with some individual rocks up to nearly 20 tonnes. Challenges for removal of these croys included steep river banks, deep, fast flowing water and the presence of freshwater pearl mussels. This required careful planning and optimising suitable working windows when they were available. The third project on the River Dee was in the upper reaches at Mar Lodge, near Braemar, where a 100 metre long river bank breach had been repaired in 1984 using a combination of timber, gravel, concrete, trees and cars. An environmental risk assessment had identified that there was a low risk of residual contamination. This project attracted media attention due to the presence of the old cars within the river bank, with TV and radio coverage over a number of days. A total of 30 cars were removed from the bank along with 200 tonnes of concrete, which was reprocessed as part of the contract. The works were all undertaken from the river bank during ideal weather conditions. Due to the relatively remote location, no additional materials were brought onto the site and the bank was reprofiled and restored using available materials. During the final days on site, a large spate resulted in river levels rising over 1 m within 3 hours and the river coming within 0.3 m of overtopping the newly restored bank.
These projects had been subject to detailed assessment and modelling prior to works commencing on site. Some of the predicted changes have been witnessed within a short time at the South Esk where an extreme flood occurred during the works, while others have seen little change to date.
The projects provide good examples of working in high energy gravel bed rivers within remote, sensitive environments with difficult access, and highlight the skills of the contractors and operators in completing the works.
WORKING WITH WOOD ON THE WENSUM I.P. MOSRRISSEY1, M. HUBAND1 Additional authors M. PHILPOT2, C. LABURN2, J. LOVERING3 1 Atkins Ltd, 2 Norfolk Rivers Internal Drainage Board, 3 Five River Environmental Contracting
Following the award of the inaugural England Riverprize to the River Wensum Restoration Strategy (RWRS), delivery partners have continued to drive forward and implement major improvements in line with the river’s SSSI/SAC designation and WFD objectives. Following a funding award to the Norfolk Rivers Internal Drainage Board (NR IDB), significant progress has been made in the implementation of restoration works to a substantial length (7.2km) of the Upper Wensum for which the NR IDB are the Statutory Authority. Atkins were appointed to provide the design and consultancy services and in September of 2015 the first part of a three phase construction programme was completed.
This presentation describes the design and implementation of restoration measures in this first phase of works. It focuses particularly on how the smart use of woody material has proved an effective “light touch” technique in restoring a 2km length of small headwater stream under the constraints of a modest financial budget. In conjunction with earthworks (such as berms) that immediately impose form on the channel, timber has been used to introduce habitat complexity and kick-start natural river processes that are expected to generate geomorphic forms over time.
An initial detailed design walkover survey confirmed that a “lighter touch” approach could be applied along substantial lengths of the restoration reach and wood was in plentiful supply (over 2/3 of the corridor is wooded). It also allowed identification of reaches in which the river was most likely to respond to “light touch” wood based techniques.
The “smart” use of wood, yielded from advanced tree works, was a key approach used in the design and required the combined knowledge of our on-site delivery team to ensure that the required process based restoration outcomes were achieved. Wood was utilised within the design in varying ways - including placement to encourage berm development, scour and maintain pools, link other features, accentuate vegetated berms in day lit areas, and improve habitat complexity. Significant thought was given as to how woody material should be placed in the channel (its orientation, size and structure) and each feature was assigned a set of objectives against which its performance was measured, initial monitoring results for which are presented.
As with all the RWRS schemes the design philosophy was one of a multi-benefit approach, which in this instance allowed the project to secure wider value such as flood water management and improvement in riparian habitat complexity. The paper briefly sets out how the scheme was developed in close consultation with landowners (Raynham Estate). In particular it outlines approaches taken to ensure that changes to the river needed to secure conservation objectives were carefully balanced with the land drainage / flood risk management requirements of a working estate.
PARTNERING WITH NATURE FOR SUSTAINABLE RIVER RESTORATION M.F. JOHNSON1, C. THORNE1 Additional authors S.P. RICE2 1 University of Nottingham, 2 Loughborough University
This presentation aims to: (1) draw attention to the power of ecosystems to influence physical processes and river channel forms; and, (2) make the case for more effectively harnessing the power of species and ecosystems in river restoration.
Animals adapt over ecological and evolutionary time-scales to better exploit habitats, but also modify habitats over similar time-scales. As a result, rivers have evolved in the context of a particular biome. However, conventional restoration design focuses on treating stable channel form as a function of discharge and sediment transport with, at best, some consideration of the stabilising effects of riparian vegetation or woody debris. While the morphological impacts of other organisms are less well understood, evidence is emerging that the cumulative impacts of communities of invertebrates and fish are highly significant to channel processes and form. For example, a series of laboratory experiments demonstrated that Hydropsychid caddisfly larvae bind sediment grains together with silk, which increased the flow stresses required to mobilise gravel by 33–45% in comparison to identical substrates that remained uncolonised. Given that silk-spinning caddisfly regularly occur at densities in excess of 1000 m-2, they could have substantial and pervasive impacts in many river reaches and be an important component of river biomes.
A river responds to changes in its biome, and morphological responses are distorted when the ecology of the river is substantially altered. For example, the invasive Signal Crayfish destabilises river-beds and banks by burrowing into sediments. Six-hours of crayfish activity was found to substantially alter the arrangement of substrates, resulting in twice as much material being mobilised during high flows from crayfish-disturbed substrates in comparison to those that had not been exposed to crayfish. In addition, crayfish burrowing directly introduces fine sediment into the flow and can accelerate bank collapse. Measurements from a tributary of the River Nene reveal suspended sediment fluxes are partly driven by variations in crayfish activity, with up to 50% of cumulative fine sediment load attributable to crayfish activity. Therefore, river form and function has responded to changes in its biome due to crayfish invasion.
Restored channels need to be resilient to changes in climate, catchment land-use and river management in a highly uncertain future. Rivers that are integrated within a biome can co-evolve with ecological systems, however the future unfolds. Therefore, partnering with nature’s ecological river restorers opens up the possibility of designing systems that are more resilient to disturbance and which have a self-repairing capability unique to living organisms. In addition, the chances that further human interventions will be needed are reduced because nature’s river restorers work continuously as if their life depended on it - because it does.
Princess Suite: Ecological Monitoring AN ECOHYDROLOGICAL APPROACH TO RIVER RESTORATION D. HARPER1 1 Aquatic Ecosystem Services Ltd., University of Leicester
River Restoration has always proceeded at a faster rate than its scientific justification, or generation of evidence for its success. There are many different reasons for this, but almost all of them, in Europe at least, lie in the opportunism of river restoration activities (e.g. end of financial year with money left over..), single sectoral interests (e.g. placing boulders for fish sheltering; removing weirs for fish passage) or political drivers (e.g. WFD).
I argue that the full range of different approaches could more easily be justified and monitored if practitioners used a simple ecohydrological approach. My presentation explains exactly what the ecohydrological approach is and presents a methodology derived from this and elements of the (River Habitat Survey which could help future schemes in design, implementation and monitoring.
The presentation by Al Zankana et al. provides a case study of this approach.
BIOTOPES AS DESIGN FOR RESTORATION AND UNITS FOR MONITORING SUCCESS A. AL ZANKANA1, L. SMALLWOOD1 Additional authors D. HARPER1, 2 1 University of Leicester, 2 Aquatic Ecosystem Services Ltd
The CRF project “Restoration of the Welland at Market Harborough for Wildlife & People”, together with a smaller, rural project to restore a Welland headwater stream previously straightened through a long spinney, were planned, implemented and are being monitored using an ecohydrological approach. In outline, we designed the geomorphological basis for restoration calculating channel size and meander wavelength using the first principles of geomorphology (after Leopold), central to which is the spatial prediction for natural re-establishment of biotopes in appropriate depth/current speeds. Our earlier work (Smith, Harper, Barham, 1999) showed that the integrity of biotopes using macro- invertebrates makes them surrogates for both biodiversity and ecosystem health and recent work showed the functional importance of biotopes largely missing in degraded rivers (Wasiak, 2011).
We have quantified the effects of restoration using biotope mapping and species recording of plant and invertebrate species at 3 replicates per biotope at BACI sites. The results are presented, evaluated and discussed in the context of both restoration success and suitability of the method for more widespread use.
USING BEETLES TO MEASURE RIPARIAN HABITAT QUALITY J. WEBB1, N. MOTT2 Additional authors S. HENSHALL3 1 Natural England, 2 Staffordshire Wildlife Trust, 3 Buglife
Two different databases are introduced in this presentation:
1. PANTHEON (in prep): an online analytical programme that associates invertebrate species with habitats, microhabitats and resources.
2. RIPARIA: A database of records of beetles from riparian habitats
Riparian means the interface between the land and river. Riparian habitats are a valuable conservation resource, especially when associated with unmodified rivers. There are a considerable number of specialist invertebrates found in this habitat and many of these are beetles, occurring in a variety of specific habitats, such as coarse woody debris, riparian sand and shingle, eroding clay banks, splash zones and more. These associations have been typed into PANTHEON and this typology can be used to analyse samples of invertebrates collected from riparian habitats.
28,000 biological records of riparian species have been compiled into the RIPARIA database. These records are drawn from a series of reports focusing on the survey of riparian habitats by the Environment Agency, Natural England and other surveyors. Behind each report is a series of records (mostly beetles) collected in ‘samples’. RIPARIA currently resides as an Excel database and is administered by Jon Webb, Natural England.
Analysing the data
The presence of species associated with habitats in PANTHEON can be used to qualify site interest. This is particularly relevant if used with comparative data in RIPARIA.
Figure 1 below shows a nested typology for riparian habitats (adapted from PANTHEON). This nested hierarchy allows for both specialists and generalists. A generalist riparian beetle will only be typed to the Riparian microhabitat/resource, whereas a specialist could be classed as associated with Exposed Riverine Sediments, or even to a particular sediment type (sand or shingle). Numbers in blue denote numbers of beetles in each microhabitat/resource that are associated with that particular riparian habitat; the number in yellow is a number of other floodplain species that occur in riparian habitats (such as backwaters). Fidelity scores can be attributed to any given sample of beetles by totalling the number of species found in any given microhabitat/resource.
Figure 1:
This data can be used to 1. Initiate the monitoring of riparian habitat quality with regards to river restoration projects 2. Create an alert map of important sites – those with interesting ERS faunas 3. Further inform our knowledge of ERS species; their ecology and distribution
Summary It is possible to assign scores to assemblages of riparian beetles. Such scores can assign quality to be used for monitoring, and notification. As the dataset already consists of 28,000 records we already have ‘scores’ for various rivers. These provide benchmarks and it is easy to ascribe quality to new samples by comparative analysis. Although this dataset focuses on ERS, other species associated with waterfall splash zones, eroding banks, backwaters and woody debris could also be included. Using Riparian invertebrates to monitor river restoration projects should be included in the Practical River Restoration Appraisal Guidance for Monitoring Options
THE LOGIE BURN: RESULTS OF THREE YEARS OF MONITORING S. ADDY1, M. WILKINSON1 1 The James Hutton Institute
Case studies of geomorphic change in response to active reach scale river restoration remain rare even over short (< 5 year) timescales. Field-based knowledge of channel adjustment rates and processes for different types of river are needed to reduce uncertainty and help inform river restoration planning.
Low energy, sand-gravel bed rivers are common in areas used for farming and have a long history of modification. Re-meandering is one method to improve such degraded rivers but where upstream sediment supply issues remain, recovery towards a complex meandering morphology could be impeded by aggradation due to the lower sediment transport capacity of the new channel. This could in turn reduce conveyance and degrade habitats through siltation and nutrification. However, monitoring of these potential responses is lacking.
In 2011, a 160 m reach of the Logie Burn, a degraded agricultural stream in Aberdeenshire, was reconnected to relict meanders. The main aims of the reconnection were to restore its meandering morphology, improve river habitat and enhance riparian habitat diversity. A further aim was to reduce downstream phosphorous and fine sediment transfer by enhancing in-channel storage capacity. Since July 2011, before and after monitoring of channel morphology, habitat, flow, sediment and phosphorous content responses, has been undertaken within the restored reach and an upstream control reach.
Between 2011 and 2014, geomorphically effective floods have occurred over at least a 20 day period. In response the restored reach has gained nearly 50 m3 of sediment and the particle sizes have adjusted to a distribution close to the pre-restoration channel but finer than the control reach. Despite the aggradation response, the channel capacity has increased to a pre-restoration state suggesting that conveyance adjustment can keep pace with the rate of deposition. Morphological complexity has increased and stabilised at a level similar to the pre-restoration state which is higher than the control reach. Complexity has been in part driven by the incorporation of woody material into the channel, which has been initiated by channel adjustment through bank erosion. The input of wood has also created greater diversity of flow types within the restored reach and is attenuating peak flows by forcing floodplain overspill. The diversity of visually assessed benthic habitat types has decreased to a level lower than pre-restoration but higher than the control reach. Phosphorous storage levels in the main active channel are similar to those recorded in the pre-restoration channel but are relatively higher in backwater areas.
Although the monitoring was limited by the short timescale, it shows that rapid adjustment of channel morphology and sediments is possible in low energy channels. Ongoing monitoring will help to understand the long term response of the channel and the full implications for conveyance and habitat.
Session 3: Parallel Sessions Lancastrian Suite: Addressing Multiple Objectives BALANCING FLOW – BALANCING OPINION J.A. MOON1, P. JOSE2 M. PORTER3 Additional authors R. SPENCER3, 1 Black and Vetch, 2 Wessex Chalk Stream and Rivers Trust, 3 Environment Agency
During the 2014 winter floods a breach occurred along on the left bank of the River Avon (leat) upstream of Lake Hatches at Wilsford cum Lake, near Salisbury in Wiltshire. This resulted in a dramatic change in flow apportionment causing the majority of the river to bypass the hatches through the breach into an adjacent side stream. This had major consequences for the local residents, resulting in a significant loss of amenity; the drying up of connected side channels and impacting on local fisheries.
As a result the residents were “up in arms” and wanted the breach infilled…
On the other hand, the breach created a natural bypass channel around the previously degraded and impounded mill leat channel; restoring flow dynamics and improving habitat diversity along a new channel alignment. The breach was therefore helping towards the delivery of Special Area Conservation and Site of Special Scientific Interest objectives (i.e. restoration of the reach to favourable condition) and Water Framework Directive targets. The Statutory Agencies (Natural England and Environment Agency) were therefore keen that the breach and flow along the new side channel should be retained; however, the residents were adamant that the breach should be repaired.
How to progress in the face of such conflicting views…?
The locals set up a residents committee and subsequently commissioned a design to infill the breach, which was granted Flood Defence Consent in November 2014. A condition was attached to the consent that required improvements to be made to help move the designated River Avon towards favourable status (required under the Habitats Directive) and to comply with Water Framework Directive (WFD) targets (i.e. Article 4.1c), to be undertaken within a 3 year timeframe.
The first phase of construction (i.e. infilling of the breach) was due to be undertaken in the autumn 2014; however, it had to be postponed in November 2014 due to unsafe water levels.
The Environment Agency saw an opportunity to deliver the whole project together by working in partnership. As a result a Partnership was been formed between the Wessex Chalk Stream & Rivers Trust (WCS&RT) and the Environment Agency (EA) to deliver the project, designed by Black & Veatch and funded by the Environment Agency and from residents/ stakeholders at Wilsford.
In this presentation we will discuss how these conflicting views were resolved and consensus was reached, which resulted in the project proceeding to construction in the Autumn 2015. Some of the issues we will discuss in this paper include the importance of well defined project objectives/measures of success; designing flow apportionment; and the benefits of the partnership approach to project delivery.
CONFLICT OF INTEREST IN RIVER RESTORATION: A COUNTY COUNCIL PERSPECTIVE J. DIPPIE1 1 Buckinghamshire County Council
Background: In winter 2013/14 Aston Clinton Park flooded due to a blocked culvert. Buckinghamshire County Council (BCC), the landowners, had the culvert surveyed and found it to have collapsed. BCC decided to work together with the EA to create a new strech of open watercourse which would bypass the collapsed culvert. The project was set to benefit the environmnet, reduce flood risk and it was more cost efficient than replacing the culvert.
Summary of site: The site is on the edge of Aston Clinton Park (488026, 211623), SE of Aylesbury in Buckinghamshire. A tenant farmer uses some of the land to graze cattle and the other part of the land is in Aston Clinton Park. A CCTV survey was used to determine the condition of the collapsed culvert and LiDAR data and historic maps were vital in assessing the low points, land use and possible routes of the proposed open channel.
Stakeholders: The different stakeholders are listed below with their priorities; Buckinghamshire County Council – reduced flood risk, protecting/enhancing the special environment and biodiversity on the edge of the Chilterns Environment Agency – reduced flood risk, enhanced biodiversity and meeting the standards of Flood Defence Consent Aston Clinton Parish Council – protect football pitches and fitness trail and maintained access to orchard area Green Park – no particular priority Tenant Farmer – to ensure the area was stock proof, access was maintained and reduce flood risk Natural England – the protection of badgers where there was a potential badger set within 20m of the excavation Aylesbury Vale District Council – ensuring parish and communities are happy about bund placement and dimensions Local County Member – support through community fund contribution
Project changes: Project plans, photos and drawings will show how the project evolved to keep all stakeholders happy. More detail about the project will be discussed to explain how the needs of all the stakeholders were addressed and met including the challenges faced. Arising challenges included: Changes in plan drawings throughout the project Moving the bund to take into account the comments of the farmer and the parish council Changing the layout of the scrapes and the location of the access gate to ensure the EA were satisfied Last minute changes to the type of seed that would be put on the bunds, recommended by BCC ecologist Updating the fencing to the perimeter of the area to ensure that it is not only stock proof but dog proof too so that the biodiversity is enhanced
Ensuring that all the parties are represented on the interpretation board paid for by the Community Trust Fund
Photos and videos of the completed project will demonstrate the effectiveness of the project as it has evolved over time.
RIVER RESTORATION PITFALLS AND SUCCESSES FROM CONCEPT TO MONITORING J. MANT1, M. JANES2 1 Ricardo AEA, 2 River Restoration Centre
River restoration has evolved from a singular organisation’s or individual’s drive to achieve ecological benefit to one that engages multiple stakeholders (nationally and locally) in both the decision making and delivery process. In terms of raising the profile of river restoration this is a positive move forward. However, it brings with it inevitable challenges as different sectors often have varying priorities with local concerns often related to land take or flood risk and even questioning project benefit. This together, with the need for national agencies to comply with EU environmental directives has identified the need to appraise new working practices and ways of cost effectively appraising river restoration outcomes. During 2015 RRC carried out two such assessments for two very different systems, namely: the New Forest streams and the Cumbria River Restoration projects. The key best practice findings will be presented with the aim of supporting best technical, monitoring and delivery practice for future project partnerships.
Louis Suite: Beaver Reintroduction RESTORING BEAVERS TO DEVON: UNDERSTANDING THEIR IMPACTS M. ELLIOTT1 Additional authors R. BRAZIER2, P. BURGESS1, R. CAMPBELL-PALMER3, D. GOW4, H. GRAHAM2, A. PUTTOCK2, C. TURNER 1 Devon Wildlife Trust, 2 University of Exeter, 3 Royal Zoological Society of Scotland, 4 Derek Gow Consultancy
In early 2014, beavers were found to be breeding in the wild on the River Otter in east Devon. Following a campaign by local residents and national experts, Devon Wildlife Trust on behalf of the River Otter Beaver Trial was granted a licence by Natural England to re-release beavers back into the river for a 5 year trial, once they had been tested for diseases and proven to be Eurasian beavers. The trial will seek to examine the impacts on the riparian corridor, its ecology, geomorphology, and the people that live and work in this productive agricultural landscape.
With the licence in place, 5 beavers were captured by ecologists from the Animal and Plant Health Agency in February 2015, and a detailed health screening was carried out by specialist vets from the Royal Zoological Society for Scotland. All the beavers were shown to be healthy and Eurasian beavers, and were then returned to the River Otter in late March 2015. Conditions attached to the licence include that the beavers must remain in the Otter catchment, and that a fully funded exit strategy is in place to remove the animals should their impacts be deemed unacceptable.
The objectives of the trial are to: • Understand the ecology, behaviour and population dynamics of a beaver population in a lowland, productive agricultural landscape, • Identify and assess impacts of beavers on habitats, wildlife, built infrastructure and local communities, • Identify wider public benefits associated with beaver activity in the landscape, • Increase knowledge and awareness with local communities and other key stakeholders of beavers and their interactions in the landscape, • Develop an effective management process for a free-living beaver population, • Provide data and evidence to augment national knowledge base on beaver re- introduction.
Meanwhile Devon Wildlife Trust has been conducting detailed research on the impacts of beavers in a 3ha fenced enclosure in west Devon. Over the past four years, up to five beavers have significantly manipulated their environment, creating 13 ponds by spring 2015 with a surface area in excess of 1000m². The features have been mapped annually in great detail by a team from South West Archaeology. Changes in vegetation communities and structure have been monitored, supported by a series of 160 fixed photography points. Annual frogspawn counts have shown an increase from 10 clumps in 2011, to 521 clumps in spring 2015, and a survey of aquatic water beetles has shown numbers increase from 8 species in 2011 to 26 species in 2015. The hydrological and water quality impacts have been the subject of detailed research by the University of Exeter, and this has revealed very significant changes to the flood hydrograph and water quality indicators between the upstream and downstream monitoring stations.
QUANTIFYING THE MULTIPLE BENEFITS OF BEAVER ACTIVITY ACROSS RIVER CATCHMENT SCALES R. BRAZIER1, A. PUTTOCK1 Additional authors H. GRAHAM1, M. ELLIOTT2, K.A. ANDERSON3 1 University of Exeter, 2 Devon Wildlife Trust, 3 University of Exeter
Beavers are ecological engineers with the ability to modify the structure and flow of fluvial systems and create complex wetland environments with dams, ponds and canals. Consequently, beaver activity has potential for river restoration, management and the provision of multiple environmental ecosystem services including improvements to biodiversity, flood risk mitigation, water quality and sustainable drinking water provision. With the current debate surrounding the reintroduction of beavers into the United Kingdom, it is critical to monitor the impact of beavers upon the environment. We have developed and implemented a monitoring strategy to quantify the impact of the Eurasian Beaver on multiple environmental ecosystem services and river systems at a range of scales.
First, the experimental design and preliminary results will be presented from the Mid-Devon Beaver Project where a family of beavers has been introduced to a 3 ha enclosure situated upon a first order tributary of the River Tamar. The site was instrumented to monitor the flow rate and quality of water entering and leaving the site. Additionally, the impacts of beavers upon riparian vegetation structure, water/carbon storage were investigated. Preliminary results indicate that beaver activity, particularly the building of ponds and dams, increases water storage within the landscape and moderates the river response to rainfall. Baseflow is enhanced during dry periods and storm flow is attenuated, potentially reducing the risk of flooding downstream. Initial analysis of water quality indicates that water entering the site (running off intensively managed grasslands upslope), has higher suspended sediment loads and nitrate levels, than that leaving the site, after moving through the series of beaver ponds. These results suggest beaver activity may also act as a means by which the negative impact of diffuse water pollution from agriculture can be mitigated thus providing cleaner water in rivers downstream.
Secondly, the River Otter Beaver Trial will be discussed. In 2015 Natural England granted a five year licence to monitor beavers living wild upon the River Otter, Devon. The River Otter is a dynamic, spatey system with downstream areas exhibiting poor ecological status, primarily due to sediment and phosphorus loading, which both impact on fish numbers. The impacts of Eurasian Beaver upon English river systems are currently poorly understood, with the outcome of this pilot study having significant implications for river restoration and management. This project, the first of its kind in England, is monitoring the impacts of beavers upon the River Otter catchment with three main scientific objectives: (1) Characterise the existing structure of the River Otter riparian zone and quantify any changes during the 2015-2019 period; (2) Quantify the impact of beaver activity on water flow at a range of scales in the Otter catchment; (3) Evaluate the impact of beaver activity on water quality.
BRINGING BEAVERS BACK – HOW WILL WE MANAGE THIS SPECIES? R. CAMPBELL-PALMER1 Additional authors G. SCHWAB2, H. DICKINSON3, D. GOW4, F. ROSELL5 1 Royal Zoological Society of Scotland, 2 Bund Naturschutz in Bayern e.V, 3 DCP Environmental, 4 Derek Gow Consultancy, 5 Telemark University College
The history of the Eurasian beaver (Castor fiber) represents an important case study for conservation, ecological restoration and reintroduction programmes. By the late 19th century, the once widespread Eurasian beaver was reduced to a handful of relict populations in fragmented refugia across Europe, in which potentially ~1,200 individuals survived. As beaver populations dwindled, so did the understanding of living with this species pass from common knowledge. In the beavers’ absence, landscapes continued to be altered by humans, and riparian environments in particular were engineered to suit agricultural and industrial needs.
Britain represents the very western edge of its native range, and its reintroduction has been subject to much debate and scientific investigation. Contemporary experience of expanding beaver populations demonstrates clearly that beavers can readily modify even heavily engineered landscapes to suit their own ecological requirements. Intensively utilised, cultural landscapes dominated by agricultural production with amenity woodlands, recreational areas and engineered water bodies are relatively unchallenging environments for beavers. Though it has been well demonstrated that environmental factors such as topography, hydrology and vegetation influence beaver distribution, they are clearly a much more adaptive species than was initially believed. The Eurasian beaver is a well-studied species which is perfectly capable of providing biodiversity and economic benefits through its natural activities. Its restoration is broadly considered internationally to be a clear conservation success.
The return of the beaver through a combination of reintroductions and natural re-colonisation has often been viewed as a novel phenomenon. When beaver populations initially re-establish, the physical impact of their activities is often only felt by a small group of land-users such as farmers, foresters or water authorities. As their populations increase, the novelty of their presence can be replaced by hostility from wider elements of society when more visible impacts occur such as the felling of specimen trees in public parks. It is inevitable that a process whereby people ‘rediscover’ what it means to live with beavers will become a critical component of coexistence. Understanding, tolerance and a willingness to manage undesirable aspects of beaver activity competently will also be of fundamental importance.
The impacts of beavers will be generally limited to freshwater and riparian areas, with >95% of all beaver activities occurring within <20m from fresh water. A range of mitigation techniques have been common employed, from individual tree guards, flow devices to control dam levels, to more extensive flood bank protection. Such techniques are presented here.
It is likely that any future programme of beaver-management in Britain would be an evolving process as established populations expand and applications for further releases are approved. This is subject of course to the decisions of the English, Welsh and Scottish Governments regarding the future of beavers.
Princess Suite: Understanding sediments ACHIEVING MEASURES FOR HEAVILY MODIFIED WATER BODIES USING SEDIMENT MANAGEMENT M. BUCKLEY1, K. KEMBLE2 1 United Utilities, 2 Jacobs
Heavily Modified Water Body (HMWB) assessments were carried out by the Environment Agency on a number of watercourses within the Lake District, Peak District, Bowland and around Manchester. This predominantly covered water bodies with reservoirs or intake structures within these catchments. Following the initial assessment a number of sites were identified for further study by United Utilities to establish seven potential sites which required the development of sediment management plans.
Sediment management is a key practice in working towards the improvement of HMWBs under the Water Framework Directive (WFD), acting to implement a number of the assigned mitigation measures. Intake impoundments and, in particular, reservoirs act as large ‘traps’ of sediment that would typically have been transferred down the system to downstream reaches. Below the structures the river is often starved of sediment, particularly coarser gravels and sand, with a stable armoured bed often observed. The lack of particular sizes of sediment within the system is likely to have detrimental impacts on the habitats, ecology and the natural geomorphological processes and functions.
Sediment management can take many forms and the proposals vary depending on a number of key features including catchment characteristics, type/size of sediment within the system, structure maintenance/control and accessibility.
The implementation of sediment management plans is a relatively new concept and water companies are beginning to drive the process forwards to ensure compliance to the legislation. The case study presented within this paper provides an overview of seven sites identified as HMWB where sediment management plans are currently being explored. It looks into the key issues, potential solutions and practicalities of using sediment management to improve the status and morphological capacities of the WFD water bodies.
WEIR POOLS AND HYDROPOWER: METHODS TO ASSESS IMPACTS S. PALMER1 1 APEM Ltd
Weir pools represent hydromorphologically diverse and sometimes extreme environments, whereby the processes of scour and deposition driven by turbulent flows create conditions favoured by rheophilic species such as chub, dace, and barbel. On impounded rivers such as the River Thames and River Severn, gravel below weirs may be the only substrate available for lithophilic spawners.
The recent growth in run of river, low head hydropower in England and Wales has led to concern over the impacts of such schemes on weir pool ecology and hydromorphology by both regulators and angling organisations leading to the publication of the Guidance for run-of-river hydropower: (Geomorphology (including weir pools)), and commissioning of a recent Environment Agency R&D project on the same subject. The hydropower guidance requires characterisation of the changes to sediment dynamics, flow characteristics, and in turn fish habitat as a result of the proposed scheme.
Where changes to the weir pool are deemed to be adverse, river restoration techniques can be planned to prevent, or even improve conditions with the construction of a hydropower scheme.
This presentation details field studies of weir pools on several large rivers in the UK where hydropower schemes are proposed. Our studies employed bespoke equipment to enable field sampling of sediment and hydraulic characteristics in turbulent deep flows, and applied techniques such as 2D modelling, sediment transport calculations and habitat suitability indices to determine likely changes in hydromorphology as a result of the hydropower schemes, and translate these effects into possible impacts on fish.
Using a combination of methods to assess weir pools, it is possible to predict whether any alterations in the flow conditions caused by proposed hydropower schemes will cause adverse impacts on the hydromorphology and ecology of the pool. Subsequently, river restoration techniques, informed by the various survey tools and techniques, can be planned during the design of the hydropower schemes to ensure no adverse impacts occur.
RAPID BIODIVERSITY GAINS TRHOUGH NATURALISATION: PROCESS BASED SUCCESS S. BENTLEY1, K. SHEEHAN2 1 AECOM, 2 JBA Consulting
River and floodplain naturalisation offers a number of advantages over conventional restoration approaches. Encouraging morphological development aligned with contemporary process will generate a sustainable fluvial system promoting an appropriate physical template for the ecology of the system. This presentation details the ecological gains achieved after five years at two naturalisation sites in England.
The River Ribble at Long Preston Deeps is an active wandering channel system which frequently transports gravels, and deposits them in areas with a good connection to the floodplain forming large gravels bars. These bars encourage lateral erosion and channel change where flow is concentrated towards the banks. The system is slowly recovering from a past dredging regime and naturalisation to improve floodplain connectivity is already promoting the development of a diverse channel, riparian and floodplain morphology, particularly in the form of extended transverse and mid-channel bars. The previously disconnected floodplain was characterised by improved grassland, subject to trampling. This typically included Perennial Ryegrass (Lolium perenne) with Greater Plantain (Plantago major) and Pineapple Mayweek (Matricaria discoides) in the trampled areas. Subsequent to the naturalisation measures the biodiversity has increased on the riverbanks and on bars, with several key species being recorded across the site including Reed Canary-grass (Phalaris arundinacea), Creeping Yellow-cress (Rorippa sylvestris) and Dame’s Violet (Hesperis montana). Some of this recovery in the vegetation is due to the removal of grazing, however, it is encouraging to note the presence of R. sylvestris, a species more typical of mobile gravel bars, rather than silt bars. Gravel bars are also in the process of being colonised by woody vegetation, which is developing from tree fragments deposited in the gravels. These, in time, will further increase the diversity and morphology of the riparian system.
The River Trent at Catton has been significantly modified through dredging, over deepening and widening, straightening and river bank protection. This has resulted in a disconnected floodplain in many locations with flood flows concentrated in the channel. Naturalisation through the
encouragement of anastomosis has allowed large gravel bar and stable island features to develop. Ruderal species such as Common Bent, (Agrostis tenuis) and Dandelion (Taraxacum officinale) have been replaced by assemblages more tolerant of flood inundation and disturbance with species typical of pools appearing at the site, such as Horned Pondweed (Zannichellia palustris) and Upright Burr-reed (Sparganium erectum). The growth of Reed Canary-grass along the banks in the absence of grazing is also very pronounced.
It is clear from these rapid biodiversity improvements that naturalisation is working with regard to the ecology and geomorphology and this generic approach should be favoured over conventional stability driven restoration approaches.
Day 2: Wednesday 27th April Session 6: Parallel Sessions Lancastrian Suite: Barrier Removal PROVISION OF FISH PASSAGE IN THE WORFE CATCHMENT I.J. STEWART-RUSSON1 1 APEM Ltd.
More than 70 potential barriers to fish migration were identified by APEM Ltd. on the River Worfe catchment as part of the Severn Rivers Trust’s (SRT) River Worfe Catchment Restoration Project (previously presented by APEM during the River Restoration Centre’s 2015 Annual Network Conference), funded via DEFRA’s Catchment Restoration Funding initiative. To improve ecological status in the catchment, SRT subsequently sought to apply fish passage measures to as many of these barriers as possible, within the constraints of their limited budget and timescale.
To provide the ‘biggest bang for the buck’, a prioritised strategy was conceived in July 2014 by APEM, aiming to deliver fish passage provision at priority locations in the catchment, by the end of March 2015. This involved:
1. Prioritising 20 of the previously identified obstacles for detailed fish passability assessments; 2. Undertaking a coarse resolution fish passage options scoping exercise to identify potential options for full fish passage options appraisals and feasibility studies; 3. Undertaking full fish passage options appraisals and feasibility studies at 10 high priority sites; 4. Producing detailed designs, obtaining all relevant permissions, and arranging delivery of fish passage mitigation at as many of the high priority sites as feasible in the budget.
During the prioritisation process a number of factors were taken into consideration including, but not limited to, the structure’s level of impediment to fish migration, it’s location in the catchment, and the presence of invasive non-native species and protected species (in particular crayfish, where both invasive signal and native white clawed crayfish are present in the catchment).
The final outcome of the project was the provision of fish passage facilities at five structures: the removal of a weir, a multi-species pass on a Crump Weir, a partial weir removal, and two eel ramps. This presentation discusses the theories, challenges, and practicalities involved with undertaking such a project; highlighting that delivery can be achieved in extremely short timescales.
INNOVATIVE FISH PASSAGE DESIGN ON AN EAST LANCASHIRE RIVER A.J. WALMSLEY1, J.W.A. SPEES1 Additional Authors M. FORTY2 1 Ribble Rivers Trust, 2 Durham University
The Colne Water Catchment Restoration Fund Project aimed to restore this failing waterbody through a combination of habitat restoration and fish passage measures. Seven redundant mill weirs were identified along the course of Colne Water, remnants of Colne’s industrial past. The most upstream and largest was a weir on the edge of Ball Grove Local Nature Reserve. A total height of 3.5 m and a complex shape, consisting of a concave concrete crest, a vertical step and a long stone-clad apron with
a varying gradient presented a challenging site. Service checks revealed mains sewer pipes running close, parallel and crossing under the river near to the toe of the weir.
Removal of this weir was not an option, due to geomorphological impacts on the services, nature reserve footpaths and a mill lodge in close proximity. The resulting preferred solution was a rock-ramp fish easement, which have worked well in similar debris-rich rivers around the catchment. However there was a lack of space to accommodate a typical rock-ramp with a suitably shallow gradient to enable fish passage. The ramp would have extended into the lower weir pool, interfering with the sewer pipe and affecting a popular swimming and fishing location. Consequently, we came up with a sinusoidal rock ramp design which allowed us to extend the effective length of the channel within the limited space we had.
The design process was very collaborative and involved the design consultants, Trust staff and construction contractor. It took multiple iterations to arrive at the final design, which everyone was happy with. Due to its complex shape, the construction drawings were difficult for the contractor to visualise, so a 3D model was built from cardboard and aquarium gravel to give them a better understanding of the desired outcome, which further demonstrates the innovative thinking behind the project!
Issues encountered during the construction phase included the discovery of a boulder clay substrate beneath the stone sets of the weir apron, necessitating the excavation of a trench, installation of sheet piling and a concrete foundation for the boulder groynes forming the backbone of the easement. Frequent wet weather events resulting in rapid water-level rises in the flashy river, caused construction delays and problems for access through the public park.
The ecological success of this project was measured through collaboration with a PhD student from Durham University who carried out radio tracking of brown trout in Colne Water, showing the new fish easement to be effective. Monitoring also led to the downstream discovery of salmon fry in Colne Water for the first time, and so it’s hoped that in the near future salmon will utilise this new easement.
LESSONS LEARNT AT A NORFOLK MILL J. WHITMORE1 Additional Authors P. GEORGE2, J. WOOD2 1 JBA Consulting, 2 Environment Agency
How many plates is it possible to keep spinning when planning and delivering barrier removal projects? Trowse Mill on the River Yare in Norwich seems like a relatively simple site: a relic mill converted to flats that now serves to maintain upstream levels for abstraction, whilst also performing a flood risk management function. A channel bypasses the mill on the right bank of the Yare and on the face of it, represented an ideal opportunity to provide fish passage round the mill without too much structural intervention. However, the need to balance meeting stakeholder needs, consider flood risk management, and deliver wider biodiversity gains and an efficient fish easement, meant that the final solution was not that simple.
Phase 1 of the project involved appraising the opportunities for delivering fish passage improvements using the bypass channel. The presence of a significant road culvert and its impact on
hydromorphological processes limited the delivery of a maintenance free option. Similarly, the use of the existing bypass channel could not deliver best practice guidance on the co-location of the fish easement and the barrier to migration. Use of the bypass channel did however present valuable opportunities for delivering wetland and in-channel habitat enhancement at the same time as improved fish passage.
Phase 2 of the project focused on the development and implementation of a design that utilised the existing mill leat. This phase involved assessing the feasibility of removal of one of the Environment Agency sluice gates whilst maintaining upstream water levels by re-grading the approach channel to the mill. Although introducing a difference set of constraints, including structural integrity of the mill itself, this option allows for delivery of the entrance to the fish easement at the point of the barrier to migration, thereby maximising the chances of finding the entrance to the easement.
Points of interest arising from project planning and delivery which will be covered in the presentation include:
- Management of the balance between stakeholder engagement and a starting point of an unconstrained list of options, - Are there efficiencies to be realised beyond the immediate scope of the project objectives? - Successful design and construction of the project will win trust with the local community and stakeholders. This has the potential to open up the possibly for further restoration within the left bank mill leat. This in turn could lead to a scheme being developed with a significant element focused on the reduction in flood risk. Phase two design has had to address these potential future needs.
Louis Suite: Shaping Our Rivers THE IMPORTANCE OF REFERENCE STATE AND THE ASSESSMENT OF POTENTIAL FOR GEOMORPHIC WORK H. MOIR1 1 cbec eco-engineering UK Ltd.
Successful river restoration cannot be applied with a ‘one size fits all’ type of approach. Different types of river environment and degree of constraint of natural processes require the application of different approaches to delivering restoration. Not only must the specific configuration of a river restoration project reflect the imposed physical controls at a site (i.e. reflect the reference condition), but there are different general approaches that are best suited to delivering that configuration. These can be summarised through an increasing degree of intervention of ‘do nothing’ – ‘assisted recovery’ – ‘initial condition design’ – ‘functional design’, associated with gradients of increasing physical constraint and decreasing potential for geomorphic work. However, to date, there have been few attempts to quantitatively define and apply this type of framework. In this presentation we present an application of such an approach on the River Leven catchment, Scotland. Catchment-wide data on the degree of engineering pressure (based on SEPA’s MImAS ‘capacity used’ score) and indicators of the potential for geomorphic work (combining information of specific stream power and unit channel length sediment supply and storage) are integrated to provide a standardised metric that, 1) prioritises restoration for greatest WFD benefit, and, 2) identifies what type of general restoration approach is appropriate for those prioritised areas.
A METHOD FOR DEFINING POTENTIAL LOCATIONS FOR WFD AND FLOOD RISK RESTORATION IN A LARGE CATCHMENT K. KEMBLE1, S. ROBERTS1 1 Jacobs.
Some catchments are so large that traditional methods of identifying areas at potential risk, or that would potentially benefit from restoration, are not viable. High level strategic assessments on a catchment scale using Geographic Information Systems provide an opportunity to potentially gain an insight into the sensitivity of the catchment. By using the findings from this type of assessment tool, key areas at risk or with potential for enhancements can be derived and highlighted for further assessment.
This paper draws on an example from the Republic of Ireland. The River Shannon catchment is located to the west of Ireland and is approximately 18,000km2. Jacobs were tasked with developing a tool to identify areas at risk geomorphologically to inform selection and the design of potential areas for flood risk management and WFD restoration. The approach used has taken into consideration the uncertainties of working at such a strategic level with limited data and information. Two complimentary geomorphological approaches were used independently to increase confidence in the observations made.
The first approach typed the catchment by using variables including the altitude, historic channel activity and geology. Using this information a high level understanding of river channel types and associated potential risks of erosion and deposition were developed. The second approach used
various data and information sources to obtain measurements of slope, stream power, sinuosity, land use, soil type, bedrock, historical change, structures and waterfall locations for the catchment, albeit at a strategic level. From this a series of scenarios were created using the variables to create three outputs highlighting risks of erosion and deposition and a specific output focusing solely on stream power and soil type.
Both approaches identified key parts of the catchment that could potentially be at risk of erosion and/or deposition or more generally of morphological change. It should be noted that both approaches are strategic and that at this level the data/information is not focused on individual channels. Site work would then be proposed at the key locations to ground truth the strategic findings and the analyses drawn.
The two approaches led to similar findings, suggesting some form of validity in the information/data used. The two approaches have allowed the potential for geomorphological change to be assessed across the entire Shannon catchment and specifically for the management units used in the wider supporting hydrological study.
BALANCING RISK AND REWARD: A CALL FOR A (SLIGHTLY) MORE CAVALIER APPROACH TO RESTORATION G.L. HERITAGE1, S.BENTLEY2 Additional Authors N.S. ENTWISTLE3, K. SHEEHAN2 1 AECOM, 2 JBA Consulting, 3 University of Salford
River Restoration practice in the UK has evolved over the last 30 years from the engineer led methodologies of the 70s and 80s designed to create semi-artificial habitats in degraded watercourses, through to the process based naturalisation projects increasingly being conducted today, driven by the requirements of the European Water Framework Directive. This development has, however, been slow, and in many cases isolated due to the perceived degree of risk associated to system stability and flooding.
Fundamental to this is the general lack of cognizance paid to understanding system form and function during restoration design, with the scientific information based on river and floodplain character and dynamics largely remaining unutilised by practitioners in favour of semi-generic approaches to re- engineer. There are numerous case studies that highlight where this engineered approach, moving a system back to a former state or attempting to recreate channel form with little reference to current process, has not worked, such as the River Wharfe, Lark and Holm Burn that will be discussed in this presentation.
From a consultancy perspective this failure to integrate advances in fluvial knowledge into the current restoration process has led to a formulaic approach to channel design. This is effectively encouraged by regulators who remain risk averse, concentrating on minimising the possibility of channel change by continuing to suppress natural processes through over-engineering.
This current restoration culture requires challenging and a number of largely rural schemes are employing science driven, process based approaches that anticipates and accommodates change due to natural processes. Such approaches are also possible in more restricted urban settings but again
require the application of process based knowledge linked to a more adventurous vision from practitioners and regulators regarding change as a necessary component of river restoration where natural processes operate to regulate form and function. Case studies will be presented based on the authors’ experiences of several projects where system stability and flood risk concerns were overcome through a successful science based approach and appropriate consultation and where risk aversion led to a compromised restoration approach. We argue that perceived risks can be identified and potentially mitigated through appropriate audit and interpretation allowing river managers and regulators must take more chances with regard to river restoration and naturalisation particularly where the consequences of failure are low.
Princess Suite: Modelling: Tools and Techniques INTEGRATED DYNAMIC ANALYSIS OF MODIFIED CHANNELS: DEALING WITH CONSTRAINTS IN URBAN AREAS I. BENTLEY1, G.L. HERITAGE1 1 AECOM AECOM have completed a number of integrated analyses of sites across England where modified channels are currently at odds with dynamic river processes creating major challenges to the maintenance of the system. The river systems investigated are characterised by a strong coarse sediment supply and active bedload transport regime moving significant volumes of gravel through the system, some of which is deposited to form bars at various locations along the channel. These gravel deposits are seen as a potential source of flood risk particularly at bridge openings. Our analysis incorporated geomorphology audit, detailed hydraulic modelling combining 1D within the catchment and 2D of the modified section, and river engineering condition assessment.
At one site an existing compound weir located 30m upstream of the bridge is believed to have been originally intended to prevent the gravel deposition by increasing the velocity of flow at the bridge but is now in poor condition. The geomorphic audit suggested a strong sediment supply and high propensity for deposition at the bridge due to the planform configuration. A detailed 2D hydraulic model of the river channel in this location was constructed, using InfoWork ICM modelling software, to aid understanding of the current hydraulic and sediment transport regimes and the effect of the existing weir structure incorporating topographical survey of the channel bed and banks. The 2D channel model was used to improve understanding of the current sediment transport regime at the bridge and to assess potential engineering options to improve flood conveyance, including simulation of an equilibrium bar based on regime theory, high flow bar low, modifications to weir structures and channel bed and the construction of a baffle to increase the velocity of flow at the bar location. The modelling included an assessment of the flow needed to transport gravel from identified sediment sources upstream and considered bar dynamics with regard to the sediment transport potential predicted in the vicinity of the bridge. A 1D hydraulic model of the sub-catchment river channels was also used in the study to assess the impact of the river processes on flood risk, since the 2D model was not able to accurately predict the effect of surcharging of the bridge at very high flows.
The combined results suggest that local engineering alone will not prevent bar deposition at the site and further upstream gravel control options identified in the geomorphic audit are being investigated.
HABITAT MODELLING: A USEFUL DESIGN, INVESTIGATION AND APPRAISAL TOOL D. MOULD1 1 JBA Consulting JBA have used hydraulic habitat modelling (i.e. using hydraulic models to quantify the habitat available in a river for a given species/life stage of interest as a function of depth and velocity) in a range of applications. The basis of hydraulic habitat modelling will be outlined, and its functionality explored using three recent JBA projects as examples:
Design. Used to firstly understand the hydraulics in the reach followed by the modelling of a number of options and the iterative design of the preferred option to optimise the amount of
habitat availability in the new channel. Illustrated using the Dinorwig project, where habitat for Arctic Charr spawning was optimised. Investigation. Used as a key element of the Environment Agency’s Science report (SC120077/R1) into the ecological impacts of hydropower on weir pools. The modelling applied at three case study sites allowed the assessment of some of the impacts of the hydropower schemes across the flow regime. Appraisal. JBA were commissioned by the EA to model a recently completed river restoration study on the Lark. An existing 1D ISIS model, combined with as-built information allowed the success of the restoration scheme to be impartially assessed.
Through these three case studies, the pros and cons of hydraulic habitat mapping will be drawn out. Advantages include, the ability to evaluate hydraulic habitat across the whole flow regime, the spatial nature of the outputs, the ability to produce results in a data-poor situation and the ability to change model topography to optimise or minimise the impact of designs. Disadvantages include, the costs of survey data and the associated scale of the modelling, and the limitations associated with knowledge of the behaviour of many aquatic species.
HYDRAULIC MODELLING REQUIREMENTS FOR RIVER RESTORATION: METHODS FOR MINIMIZING (NOT JUST FLOOD) RISK E. GILLIES1 1 cbec eco-engineering UK Ltd.
Many of the risks in river restoration are dependent on unknown changes to the design hydraulics, such as changes to water surface, depth, velocity and shear stress. These changes to hydraulics in turn can lead to unknown evolution of the river form over time, and so a common restoration design goal is often a stable channel. A change to floodplain inundation is often the design goal in NFM and river restoration; not only must any potential flood risk to property, agriculture and infrastructure be documented, but the efficacy of flood storage or floodplain reconnection measures be calculated. There is no point spending money on construction if the restoration affords little benefit. In other restoration projects, the design goal is to improve habitat, and so details of depth and velocity, and changes to substrate distribution are often required to assess restoration efficacy and potential risk to in-channel species. In another class of restorations it is desired to minimize erosion or restore a natural sediment transport regime.
Typically the only way to predict how the river hydraulics will change after restoration is to use a computer model; however hydraulic models are not all equal: ones designed purely to estimate flood risk are different to those capable of assessing changes to habitat or erosion potential and sediment transport. The multitude of different goals of a river restoration often requires a wide range of river processes to be modelled as accurately as possible. Many of the traditional models used in the UK for hydraulics are simply unsuited to restoration eco-hydraulics as they either cannot accurately model shear stresses nor can they model details at fine enough scales.
Not only are many flood risk models not detailed enough for assessing the multiple goals of river restorations, they are often not capable of assessing any lateral flow process, which is something that occurs in almost all natural channels. In many straightened reaches of appropriate stream power and sediment supply, meandering planforms are the un-impacted reference condition, and restorations
often allow natural recovery to the meandering state or construct design meanders. These turns of the river are a good example of where lateral flow process is important. The effects of lateral process are many and include super-elevation of water levels at bends, and overbank momentum transfer between channel and floodplain flow. Even for flood risk assessment, most restorations are better studied with a model that captures lateral process.
We will discuss the advantages and disadvantages of a range of hydraulic model types (i.e. 1D and 1D/2D models, and fully 2D models) for river restoration and demonstrate, by example, restoration effects that are simply not captured using certain models.
Session 7: Lancastrian Suite DELIVERING SEVERN TRENT WATER’S FAIR SHARE OF THE WFD A. BANHAM1, M. STREETLY2, D. BRADLEY3 Additional Authors M. O’KANE1, Z. REVILLE1, C. YOUNG2 1 Severn Trent Water, 2 ESI, 3 APEM Ltd. The National Environment Plan (NEP) is a list of environmental improvement schemes that ensure that water companies in England and Wales meet European and national targets related to water. In recent years the NEP has been one of the most important mechanisms for delivery of the Water Framework Directive.
This talk provides an insight into how Severn Trent Water has delivered its NEP obligations over the last 5 year spending period (AMP5: 2010-15) and its plans for delivery under its current business plan (AMP6: 2015-2020). In AMP5, Severn Trent Water was required to investigate 31 sites across the Midlands which the Environment Agency had identified as being potentially at risk of failing to meet Good Ecological status under the WFD due to abstraction pressure. The investigations included desk studies, and focussed field investigations including monitoring and testing. Impact assessments and options appraisals were then carried out.
As a result of these assessments, 12 sites were carried forward in Severn Trent Water’s new business plan for implementation in AMP6. Solutions at these sites will include a wide range of actions including abstraction reduction, changes to compensation flows and river restoration/hydromorphology. Severn Trent Water is looking to deliver these in partnership with other stakeholders in the catchment where appropriate. There will also be some synergies with Catchment Management activities being carried out by Severn Trent Water to protect water quality at its public water supplies.
At some of the sites investigated in AMP5, abstraction by Severn Trent Water was clearly not the major cause of any perceived environmental problems whilst at others, it was not clear based on the available data. These latter sites have been carried forward into AMP6 for further investigation together with a long list of new sites identified by the Environment Agency in the meantime.
Going forward, Customer Challenge Groups will be increasingly important for deciding what customers will pay water companies to deliver and it will be essential that water companies can show real value to the public through the measures they are implementing.
HOW WE ACHIEVED GOOD ECOLOGICAL POTENTIAL B. DAVIES1, D. WEBB2 1 South East Rivers Trust, 2 Environment Agency
The River Wandle in South West London is a Heavily Modified Water Body and as such has a target of reaching Good Ecological Potential (GEP) under the Water Framework Directive by 2015. When the first River Basin Management Plan was published in 2009, the Wandle Trust (now the South East Rivers Trust) was keen to meet this target on the Wandle Carshalton waterbody and began working with a variety of partners to enhance the river and reinstate natural processes. It soon became apparent that, whilst Good Ecological Status was clearly defined, there was no such clear definition for
GEP. The Environment Agency (EA) area team worked with the Wandle Trust, the Wandle Catchment Partnership and EA national staff to create a definition of GEP for the river. This involved defining both a process by which the attainment of ‘Good’ could be confirmed and the measures that needed to be implemented to reach GEP.
The process to set the goal of GEP involved:
Defining the wider community benefits that GEP would provide. This involved extensive community workshops using a Ketso toolkit to develop an ecosystem services approach. Confirmation that other elements were at Good. This involved setting objectives for Good for each element and required the fisheries classification for the waterbody to be revised by a technical panel. The identification of ‘no deterioration’ measures; Agreement of the above through a peer reviewed process; and Confirmation that the hydromorphology was at Good status (which on the Wandle required a National Environment Programme investigation by the water company) and the identification of any hydromophological mitigation measures.
The Mitigation Measures that were implemented on the Wandle Carshalton waterbody included a range of weir removal, weir lowering and fish pass measures; a variety of instream habitat and hydromorphological diversity enhancements; the preservation and enhancement of the riparian zone and aquatic habitat; the installation of a range of innovative water quality enhancement measures; and the education of landowners on sensitive land management practices.
With the process complete, the Wandle Carshalton waterbody is thought to be the first urban river in the country to have reached GEP. Early monitoring indicates that the ecology of the river is responding, with the successful recruitment of brown trout for the first time in over 80 years.