Allan Water Natural Flood Management Techniques and Scoping Study
Document: R01 Version: 2
Scottish Environment Protection Agency
September 2011
Allan Water Natural Flood Management Techniques and Scoping Study
Scoping Report
Scottish Environment Protection Agency
September 2011
Halcrow Group Limited 16 Abercromby Place, Edinburgh EH3 6LB tel 0131 272 3300 fax 0131 272 3301 halcrow.com
Halcrow Group Limited and CRESS have prepared this report in accordance with the instructions of client Scottish Environment Protection Agency for the client’s sole and specific use. Any other persons who use any information contained herein do so at their own risk.
© Halcrow Group Limited 2011
Allan Water Natural Flood Management Techniques and Scoping Study
Document history
Allan Water Natural Flood Management Techniques and Scoping Study Scottish Environment Protection Agency
This document has been issued and amended as follows:
Version Date Description Created by Verified by Approved by
0.1 09/05/11 Interim draft to inform steering Neil Nutt J Drake J Drake group and assist pilot project Charles Perfect selection process.
0.9 23/06/11 Interim draft of first issue ahead Neil Nutt J Drake J Drake of June steering group meeting Charles Perfect
1.0 29/06/11 First issue, for steering group Neil Nutt J Drake J Drake comment Charles Perfect
2.0 06/09/11 Final issue Neil Nutt J Drake J Drake Charles Perfect
Allan Water Natural Flood Management Techniques and Scoping Study
Executive Summary
The Allan Water is a tributary of the River Forth and has a catchment area of approximately 216km 2. The catchment is predominately upland with notable areas of improved agricultural land, moorland and forestry. In the lower reaches the Allan Water passes through the towns of Dunblane, Bridge of Allan and a number of villages. Parts of these towns and villages are thought to be at flood risk as highlighted by flooding in 2006.
As part of this study which has been led by SEPA, Halcrow-CRESS have investigated the factors which would influence the implementation of natural flood management measures within the Allan Water catchment with a view to the development of a natural flood management strategy for the catchment. The development of the project has been overseen by a Steering Group with representatives from:
• Forestry Commission Scotland & Forest Research
• Perth & Kinross Council
• RSPB
• Scottish Government
• SEPA
• SNH
• Stirling Council
A comprehensive catchment reconnaissance survey has been undertaken to provide a detailed baseline of the ecological and geomorphological conditions within the catchment. This initial data collection has also included meetings with land managers to gather their experiences of how the catchment operates in flood events but also to get insights into how they manage the land and what they would like to see in an eventual natural flood management strategy. The consultation process has also been extended to include a website and mail drop to the identified landowners.
A broad scale catchment restoration strategy has been developed for the Allan Water catchment based on the findings of the catchment reconnaissance and a desk based GIS analysis. This strategy identifies priority areas for catchment restoration activities such as landuse change, reach restoration and flood plain reconnection. The strategy is intended to form the basis of guidance which can be provided to land managers, Local Authorities, community groups and charities.
A detailed option appraisal process has been undertaken to identify which natural flood management measures will be most effective within the Allan Water catchment. This option appraisal has been conducted following the principles of Flood and Coastal Erosion Risk Management – Appraisal Guidance (Environment Agency, 2010) which forms current flood risk management best practice. The option appraisal was divided into three phases starting with a broad scale judgement based
Allan Water Natural Flood Management Techniques and Scoping Study
assessment of 19 options across the catchment and culminating in a detailed quantitative assessment of the four most favourable options.
The hydrological benefits of each option have been tested using a specially developed methodology based on the Soil Conservation Service’s Runoff Curve Number hydrological method as presented in TR-55 (USDA, 1986). This methodology has allowed a detailed insight into how the catchment operates in flood events and includes provision to assess the benefits of typical natural flood management measures such as landuse changes and channel restoration.
The final stage of the option appraisal process identified that, as could be anticipated, none of the considered measures have a robust case if only the economics of flood mitigation are considered. However on consideration of the wider social, environmental and economic context in which the measures would sit, the case for the implementation of natural flood management is much improved. A summary of the ranking process undertaken in the final phase of the option appraisal process is shown in Table 1.
Option Environmental and Economic Overall ranking social benefits ranking ranking
1. Muckle 3 4 4 Burn headwaters
2. Danny 4 1 3 Burn headwaters
8. River 2 2 2 Knaik riparian corridor
17. Allan 1 3 1 reduced maintenance
Table 1: Summary of the social, environmental and economic benefits and disbenefits of the considered options. Ranking, 1 is highest and 4 is lowest.
It was decided by the Steering Group that the restoration of the River Knaik riparian corridor should be adopted as the pilot project for the following reasons:
• Local perception is that the River Knaik is the dominating contributor to flood risk within the Allan Water catchment. This perception has been supported by the hydrological analysis undertaken as part of this study;
• Early consultation with the main landowners has identified that the landowners are amenable to improvements to the riparian corridor;
Allan Water Natural Flood Management Techniques and Scoping Study
• The riparian planting would be consistent with Local Biodiveristy Action Plans and the Forestry Commissions Potential Native Woodland Network. These consistencies would improve the prospect of securing funding;
• It is a sub-catchment scale project;
• The River Knaik and its riparian corridor is visible from the B827 therefore offering increased public exposure;
• The River Knaik contains good riparian reaches alongside poor reaches that will be valuable for demonstrating what is being proposed to land managers and other stakeholders. It will also demonstrate that what is being proposed is feasible;
• There are a number of similar sub-catchment reaches within the wider Allan Water that could benefit from similar riparian improvement projects such as the Danny Burn, Ogilvie Burn, Muckle Burn, Keir Burn, Millstone Burn and Wharry Burn. The restoration of the River Knaik would be a good demonstration site to these land managers; and
• The presence of cultural heritage sites in the lower catchment and the scenic Braco Falls all within walking distance of Braco offers the opportunity for significant amenity improvements through the extension of the existing path network.
The restoration of the Allan Water between Greenloaning and Blackford was highlighted by the Steering Group as a secondary pilot or flagship project. Additional scoping has been undertaken to further quantify the key constraints in regards to progressing this option. At this time the primary constraints are understood to be:
• The proximity of the reach to the Shelforkie Moss SAC, South Tayside Goose Roosts SPA and the Carsebreck & Rhynd Lochs SSSI is likely to trigger the need for an Appropriate Assessment;
• The proximity of the reach to the Stirling – Perth railway line;
• The watercourse presents a boundary between two landowners. Modifying the planform of the watercourse will have legal implications for landownership; and
• The interest of local fisheries as the reach is understood to be utilised by salmon for spawning.
It is proposed that a concept design for the restoration of this reach will be prepared by Halcrow-CRESS in August 2011 to assist in consultation.
In conjunction with the Steering Group it has been identified that the preferred pilot demonstration site for the Allan Water Natural Flood Management Programme is the restoration of the River Knaik’s riparian corridor. This can be divided into two main elements:
Allan Water Natural Flood Management Techniques and Scoping Study
i) Extensive riparian planting in the upper catchment in the vicinity of the confluence of the Corriebeagh Burn and Arrevore Burn with the River Knaik. ii) Improvements in riparian fencing with scattered infill riparian planting opportunities.
To facilitate the rapid progression of this programme additional design work has been undertaken. This design work is such that focused and meaningful consultation can take place with landowners, funding bodies, regulators and other stakeholders. The following activities have been undertaken:
• Identification of riparian planting opportunities by;
- Flood mapping of the upper River Knaik
- Site based catchment reconnaissance
• Preparation of a range of tree planting specifications (using species of local provenance);
• Identification of riparian planting opportunities by site based reconnaissance;
• Preparation of fencing specifications to protect the proposed tree planting and allow existing vegetation to increase its extent; and
• Identification of physical constraints to implementation including the location of utilities within the catchment.
To permit the concepts of the Allan Water natural flood management strategy as detailed in Section 4 of this report to transcend from a plan on paper to physical restoration projects consideration has been given to the future governance structure. To give the strategy the best opportunity it is recommended that it is implemented as series of discrete projects linked together to form a programme. Following the principles of the PRINCE2 project management approach it is recommended that a Programme Board is created to oversee the programme, this board could be based on the current Steering Group. In addition to the Board it will be necessary to appoint a Programme Manager who will have day-to-day responsibility for the success of the programme. This individual will be responsible for instilling local enthusiasm for implementing natural flood management, supporting bodies undertaking projects and facilitate the flow of information between the various bodies.
The monitoring strategy for the Allan Water has been developed following guidelines recently established as best practice and presented by the European Centre for River Restoration (Mant and Janes, 2008)
A range of biotic and abiotic elements of the river ecosystem have been considered. These are prioritised in respect to their relevance to the various purposes of monitoring. The ‘relevance’ tables can be revisited at any point during the development of a restoration or NFM project and adapted for alternative proposals.
The next stage in the development process was to consider the amount of detail required from the monitoring, i.e. how intensive surveys should be. Decisions have
Allan Water Natural Flood Management Techniques and Scoping Study
been based on a matrix of increasing project scale and levels of associated risk. Project proposals and survey recommendations can be placed on the same axes allowing recommendations to be linked to proposals.
Existing monitoring and surveys were then compared to the level of monitoring desirable for large catchment scale restoration. Gaps in the existing monitoring and opportunities for research have been identified. Following from this, schedules for implementing monitoring were drawn up. These are accompanied by a flow diagram indicating the points on the schedule at which it is important that information gathered is fed back into the project management.
Consideration has been given to how the implementation of the programme will be funded. It is proposed that the overhead costs associated with the running of the Allan Water Natural Flood Management Programme would be covered, at least in part, by a multi-year award by the Restoration Fund. With relatively secure funding in place for the Programme team it would be then feasible for this team to promote discrete restoration projects by matching funding opportunities with interested landowners and the identified natural flood management themes. In this way it would be possible for a grassroots up approach to be adopted allowing local charities, community groups, landowners and the Local Authorities to each play a role in the implementation of natural flood management. Through the adoption of this approach it is hoped that a wider range of funding streams can be accessed including donations in kind such as time, land and knowledge. To support these projects a large number of potential funding streams have been identified.
It would be desirable to implement at least one flagship project in relatively short succession after the River Knaik pilot project. The most appropriate such project is the restoration of the River Allan between Greenloaning and Blackford. The relative expense that may be associated with this project linked to the social and ecological benefits suggests a strong case for Heritage Lottery Fund or EU Life funding.
Allan Water Natural Flood Management Techniques and Scoping Study
Contents
Executive Summary ii
Abbreviations xi
1 Background 1 1.1 The Allan Water 1 1.2 Context: legislative and policy drivers 2
2 Assessment of catchment characteristics 4 2.1 Environmental context 4 2.1.1 Catchment situation 4 2.1.2 Precipitation 4 2.1.3 Soil types 4 2.1.4 Land cover 4 2.1.5 Designated sites 4 2.1.6 Water Framework Status 8 2.1.7 Water pollution levels 11 2.2 Fisheries 12 2.3 Hydrology and flood risk 15 2.3.1 Hydrometric data 15 2.3.2 Hydrological assessment 15 2.3.3 Flood mapping 19 2.3.4 Aerial photographs of 2006 flood event 21 2.4 Historic mapping 27 2.5 Strathallan wader surveys 29 2.6 Integrated Habitat Network 32 2.7 Catchment reconnaissance survey 34 2.7.1 Summary of survey extent and detail 34 2.7.2 Summary of each surveyed section 35 2.8 Summary of catchment characteristics 40
3 Landowner and community engagement 41 3.1 Introduction 41 3.1.1 Profile of interviewees 41 3.2 Views and opinions 41 3.2.1 Land-use past and present 41 3.2.2 Views on fluvial processes and flooding 42 3.2.3 Positions on flood management 42 3.2.4 Positions on river restoration 43 3.2.5 Interest in a project on the Allan Water 44 3.2.6 SRDP rural priority funding 44
Allan Water Natural Flood Management Techniques and Scoping Study
3.3 Summary 45 3.3.1 Constraints and opportunities identified 45
4 Natural flood management strategy 47 4.1 Introduction 47 4.2 Identification of opportunities to manage flood risk 47 4.2.1 Reduction of runoff 47 4.2.2 Channel & riparian corridor restoration 48 4.2.3 Floodplain reconnection 49 4.3 Conclusion 51
5 Selection of pilot project 55 5.1 Introduction 55 5.2 Initial screening of options – “long listing” 55 5.3 Qualitative consideration of options – “short listing” 58 5.4 Quantitative assessment of options – “ranking” 63 5.4.1 Introduction 63 5.4.2 Description of options 63 5.4.3 Estimation of reduction in flood risk 70 5.4.4 Estimation of baseline (existing) flood damages 72 5.4.5 Estimation of economic flood damages avoided 77 5.4.6 Estimation of capital and maintenance costs 79 5.4.7 Estimation of other benefits and disbenefits 82 5.4.8 Additional opportunities 88 5.4.9 Comparison of benefits and costs 89 5.5 Final selection of pilot projects 91
6 Monitoring strategy 93 6.1 Introduction 93 6.1.1 Purpose of document 93 6.1.2 Rational of monitoring 93 6.1.3 Approach to study design 93 6.1.4 Important considerations 94 6.2 Development of monitoring objectives 95 6.2.1 Development 95 6.2.2 Areas to be covered 95 6.3 Identifying monitoring priorities 97 6.3.1 Prioritising disciplines 97 6.4 Level of monitoring detail 100 6.5 Existing monitoring 102 6.5.1 Hydrology – SEPA Hydrometric network 102 6.5.2 Water quality – SEPA Biological and Chemical Monitoring 102 6.5.3 Fish – Forth Fisheries Trust salmonid surveys 103
Allan Water Natural Flood Management Techniques and Scoping Study
6.5.4 Morphology 104 6.6 Future monitoring 105 6.6.1 Structure 105 6.6.2 Recommended methods for monitoring a riparian restoration (River Knaik) 107 6.6.3 Schedules for monitoring 109 6.6.4 Feedback from monitoring 111 6.7 Further considerations 112 6.7.1 Integrated monitoring 112 6.7.2 Other indicators 112
7 Design and specification for pilot project 113 7.1 Introduction 113 7.2 Generation of flood maps for the River Knaik 114 7.3 Identification of riparian planting opportunities 116 7.3.1 Desk based GIS analysis of riparian opportunities 116 7.3.2 Site based reconnaissance identification of riparian improvement opportunities 117 7.3.3 Minimising impact on wading birds 118 7.4 Design of riparian restoration strategy 118 7.5 Utilities 119 7.6 Landownership 120 7.7 Progression of restoration on the Allan Water between Greenloaning and Blackford 121
8 Future structure and funding opportunities 122 8.1 Introduction 122 8.2 Progression 122 8.3 Leadership of the implementation 123 8.4 Future management structure 125 8.4.1 Programme Board 125 8.4.2 Programme Executive 125 8.4.3 Senior User 125 8.4.4 Programme Manager 126 8.4.5 Project Boards 126 8.4.6 Project Managers 126 8.4.7 Task delivery teams 127 8.4.8 Example Project Delivery Structures 127 8.5 Potential funding opportunities 128 8.5.1 Funding of the River Knaik riparian restoration pilot project 134 8.5.2 Funding of the wider Allan Water programme 136
9 References 138
Allan Water Natural Flood Management Techniques and Scoping Study
Appendix
Appendix A – Catchment characteristics
Appendix B – Catchment reconnaissance survey
Appendix C – Consultation
Appendix D – Option appraisal
Drawings – Allan Water Natural Flood Management
Allan Water Natural Flood Management Techniques and Scoping Study
Abbreviations
AAD – Average annual damage
ASPT – Average score per taxon
AST – Appraisal summary table
BMWP – Biological Monitoring Working Party (Score based on macroinvertebrates)
CAR – Controlled Activities (Scotland) Regulations
FCS – Forestry Commission Scotland
FEH – Flood Estimation Handbook
FRM – Flood risk management
HOST – Hydrology of soil types data set
HS – Historic Scotland
LCM2000 – Land cover map 2000
MCM – Multi-coloured manual, The Benefits of Flood And Coastal Risk Management: A Manual of Assessment Techniques
NFM – Natural flood management
PV – Present day value
QBar – Mean annual maximum flood
QMed – Median annual maximum flood
RSPB – Royal Society for the Protection of Birds
SAAR – Standard average annual average rainfall
SAC – Special Area of Conservation
SCS – United States Soil Conservation Service
SEPA – Scottish Environment Protection Agency
SNH – Scottish Natural Heritage
SOP – Standard of protection
SPA – Special Protection Area
SRDP – Scottish Rural Development Programme
SSSI – Site of Special Scientific Interest
Allan Water Natural Flood Management Techniques and Scoping Study
1 Background
1.1 The Allan Water catchment
The Allan Water is a tributary of the River Forth and has a catchment area of approximately 216km 2. The catchment comprises predominately upland with notable areas of improved agricultural land, upland and forestry. In the lower reaches the Allan Water passes through Dunblane, Bridge of Allan and a number of villages, parts of which are thought to be at flood risk as highlighted by flooding in 2006.
In the 19 th century the Allan Water was subject to a number of heavy modifications as a consequence of the drive to increase land availability for agriculture, abstractions for hydropower and to permit the construction of transport links, these modifications still result in the ecological status of the watercourse being poor today.
1.2 Scope of this study
The overall aim of this project is to undertake a scoping study in the Allan Water catchment to assess the potential for using natural flood management techniques to reduce flood risk to communities downstream. The project also aims to improve the status of the water bodies under the Water Framework Directive (WFD) and where possible, provide additional benefits to biodiversity, recreation and amenity.
It envisaged that this project will lead to recommendations for, and phased delivery of, practical restoration works that will potentially reduce the impact of flooding on downstream communities and improve the status of the water bodies under the WFD, as well as under the Habitats Directive. This work aims to demonstrate the contribution natural flood management techniques can make to reducing flood risk.
The project has been divided into six tasks as detailed in the following sub- sections.
1.2.1 Assessment of catchment characteristics
A detailed assessment of the catchment characteristics using a catchment wide desk based GIS analysis supplemented ground based catchment reconnaissance surveying. The assessment focused on the hydrological and geomorphological conditions but also took account of environmental, social, infrastructure and land use issues.
1.2.2 Catchment restoration strategy
A detailed appraisal of the possible restoration options based on the findings of the previous task that could help reduce flood risk and contribute to achieving the secondary aims and objectives. The appraisal includes a benefit-cost assessment of the identified options and the identification of potential barriers to implementation.
1.2.3 Landowner and community engagement
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An essential element of the project is to consult with landowners and other stakeholders to ascertain the potential and interest for implementing natural flood management measures within the catchment.
1.2.4 Monitoring requirements
This task concerns the design of a monitoring plan to assess the effectiveness of restoration measures identified in Task 2. This includes the recommendation for baseline monitoring together with a post project appraisal of the restoration success.
1.2.5 Design and specification for trial research
Based on the output of Task 2, a design and specification for a natural flood management trial site should be prepared.
1.2.6 Future structures and funding opportunities
The final task of the project should include recommendations for organisational structures to take forward the implantation of the natural flood management strategy within the catchment. This includes recommendations on potential funding mechanisms.
1.3 Context: legislative and policy drivers
In June 2009, the Scottish Parliament enacted the Flood Risk Management (Scotland) Act 2009 to implement the European Directive 2007/60/EC (the Flood Directive) and modernise flood risk management in Scotland. The Act replaces in particular the Flood Prevention (Scotland) Act of 1961, which is the basis of over 85 Flood Prevention Schemes promoted by Local Authorities, but has also restricted the opportunity to take a holistic and truly catchment scale approach to flood risk management. The new Act provides a framework to manage flood risk in a more sustainable and co-ordinated way both nationally and locally.
The Act is the result of a rapidly evolving landscape in terms of flood risk management in Scotland. This can be attributed, in part, to increased public concern following major floods in Perth (1993), Strathclyde (1994), Elgin (1997 and 2002), Edinburgh (2000), Glasgow-Shettleston (2002) and Hawick (2005), growing awareness of the threats posed by climate change (Werritty with Chatterton, 2004) and the statutory duty to promote “sustainable flood management” in the Water Environment and Water Services (Scotland) Act, 2003.
After a spate of wet summers and even wetter winters a new legislation providing the responsible authorities better ways to manage and mitigate the risk of flooding is very timely.
The Act places new duties on the Scottish Environment Agency (SEPA), and among them is the requirement to consider what contribution natural flood management techniques can make to managing flood risk.
Natural flood management (NFM) is one element of a sustainable approach to flood management and is a set of techniques seeking to work with natural catchment processes to restore or enhance the capacity of the landscape to store water, attenuate peak flows and channel flood water to where it will cause the
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least harm. Although there is growing evidence that NFM works at a local scale, the effect of NFM on the scale of large catchments during extreme events is still the subject of academic research.
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2 Assessment of catchment characteristics
2.1 Environmental context
2.1.1 Catchment situation
The Allan Water is a tributary of the River Forth, rising in the western Ochil Hills and draining 216km 2. At its downstream limit the Allan Water joins a tidally influenced reach of the River Forth close to Stirling. The NextMap based catchment delineation has been summarised in drawing WBAWPP000.The catchment rises to a maximum altitude of 631m at Blairdenon Hill in the Ochil Hills in the east of the catchment with other notable high ground to west around Ben Clach.
Drawing WBAWPP009 shows the variation in ground surface slopes across the catchment that suggests a relatively steep mean slope of 0.1m/m across the entire catchment. This compares with the FEH Mean Drainage Path Slope (DPSBAR) of 92.3m/km which is more heavily influenced by the relatively slack slope of the main Allan Water.
2.1.2 Precipitation
The variation in standardised average annual rainfall runoff for the catchment is presented in drawing WBAWPP007. This indicates that there is a notable variation in rainfall across the catchment with a mean of approximately 1326mm/yr rising to 1529mm/yr around Ben Clach while low lying areas such as Bridge of Allan are thought to experience only 540mm/yr.
2.1.3 Soil types
The Hydrology of Soil Types (HOST) is shown on drawing WBAWPP008. From this it can be summarised that the low-lying areas of the catchment are predominantly mineral soils underlain by relatively impervious substrates leading to common overland bypass flow. The HOST data also indicates that the highland areas are predominately HOST class 29, which are classified as raw peat with no significant groundwater.
2.1.4 Land cover
The Land Capability Map 2000 data, as reproduced in drawing WBAWPP004, identifies 18 land cover types across the catchment. As could be anticipated more intensive agricultural land uses follow the occurrence of mineral soils in the more low lying areas of the catchment with improved grassland followed by horticulture being predominant in these area. In the higher areas, which are underlain by peats, the dominant land cover is acid grasslands however there are significant areas of shrub heath and bog with increasing prevalence in the wetter western areas of the catchment. In the low lying south of the catchment, near its confluence with the River Forth, there is notable urbanisation at Dunblane and Bridge of Allan.
2.1.5 Designated sites
The designated sites within the catchment are shown on drawing WBAWPP005.
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2.1.5.1 Special Areas of Conservation (SAC)
There are two Special Areas of Conservation within the Allan Water catchment:
iii) Kippenrait Glen – designated for mixed woodland on base-rich soils associated with rocky slopes
iv) Shelforkie Moss – designated for its raised bog
The Allan Water discharges to the River Forth which forms part of the River Teith SAC. Therefore activities affecting the watercourse of the Allan Water could indirectly have an impact on the SAC. The qualifying features of the River Teith SAC are:
• Atlantic Salmon
• River Lamprey
• Brook Lamprey
• Sea Lamprey
• Otter
• Freshwater pearl mussel
• Transition mires and quaking bogs
• Oligotrophic to mesotrophic standing waters with vegetation of the Littorelletea uniflorae and/or of the Isoëto-Nanojuncetea
• Alluvial forests with Alnus glutinosa and Fraxinus excelsior 2.1.5.2 Special Protection Area (SPA)
The South Tayside Goose Roosts Special Protection Area is located within the Allan Water catchment in the area of Carsebreck and Rhynd Lochs. The area is an internationally important roost for both Greylag Goose Anser anser and Pink- footed Goose Anser brachyrhynchus. It should be noted that the geese protected by this designation feed in surrounding areas of agricultural land outside the SPA. 2.1.5.3 Sites of Special Scientific Interest (SSSI)
There are five Sites of Special Scientific Interest within the catchment:
i) Carsebreck and Rhynd Lochs
ii) Gleneagles Mire
iii) Kippenrait Glen
iv) Quoigs Meadow
v) Wolf’s Hole Quarry 2.1.5.4 Scheduled Monuments
The Allan Water catchment has a long history of occupation by people for thousands of years. As a result there is a significant amount of archaeology and historic monuments located across the catchment. There is a high potential that
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there are further unrecorded or undiscovered archaeological remains located within the catchment. There are 32 Scheduled Monuments situated within the catchment:
i) Airthrey Castle, standing stone
ii) Ardock, Roman militarty complex
v) Banheath, farmstead and cultivation remains
vi) Cecilmount, fort
vii) Cromlix Lodge, hut circle
viii) Cromlix Lodge, long cairn
ix) Dunblane Cathedral
x) Dunblane, Bishop’s Palace
xi) East Biggs, hut cicles
xii) Fairy Knowe, cairn
xiii) Grinnan Hill Fort
xiv) Kaims Castle Roman Fortlet
xv) Kaims Cottage Roman Road
xvi) Kippenross House, burial mound
xvii) Knock Hill, fort
xviii) Lairhill, standing stone alignment
xix) Loaninghead, fort
xx) Loaninghead, symbol stone
xxi) Orchill Fort
xxii) Pendreich, cairn
xxiii) Pendreich, cairn
xxiv) Pendreich, standing stone
xxv) Pendreich, pair of cairns
xxvi) Peterhead, enclosure
xxvii) Peterhead, standing stone
xxviii) Rhynd, enclosed settlement
xxix) Sheridd Muir, Whitestone Range
xxx) Shielhill, Roman signal station
xxxi) Roundel, burial mound
xxxii) The White Stone, standing stone
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xxxiii) Topfauld, enclosure
xxxiv) Waterside, palisaded enclosure 2.1.5.5 Listed Buildings
There are 302 listed buildings within the Allan Water catchment, of these 9 are grade A and 120 grade B listed structures. The grade A listed structures are listed below:
i) Queen Victoria School, Dunblane (3986)
ii) Principal’s House, Stirling University (51322)
iii) Cathedral Museum, The Cross, Dunblane (26372)
iv) Memorial Chapel, Dunblane (3987)
v) Pathfoot Building, Stirling University (51327)
vi) Cromlix House (3997)
vii) Ault Wharrie, Leewood Road (26365)
viii) Dunblane Cathedral (26361)
ix) Leighton Library, The Cross, Dunblane (26371) 2.1.5.6 Gardens and Designed Landscapes
There are five gardens and designed landscapes within the catchment:
i) Braco – “a good example of a small 19 th century landscape showing different elements, now much reduced, with park, walled garden, and woodland walks.” (HS website)
ii) Gleneagles Hotel – “A 20th century designed landscape most noted for its golf courses designed by James Braid, and the loch, moorland and woodland habitats that are of outstanding nature conservation value.” (HS website)
iii) Kippenross – “The designed landscape is set on gently sloping ground with the present house lying towards the south-western part of the 18th century landscaped park.” (HS website)
iv) Airthrey Castle – “The designed landscape at Airthley Castle has been developed as a university campus since 1967 and incorporates features of the late 18th- and early 19th-century designed landscape. These include the artificial lake laid out by Thomas White, wooded areas and some parkland trees. Late 19th-century conifer plantings also survive.” (HS website)
v) Keir House – “An outstanding rare example of an intact designed landscape exhibiting different styles of garden and landscape design. The parkland designed by Thomas White and the formal gardens by James Niven provide an important setting for the category A listed Keir House.” (HS website)
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2.1.6 Water Framework Status
The existing water quality status of the Allan Water and its tributaries are summarised in Table 2 and drawing WBAWPP-003. A summary of the proposed timeline for achieving a status of “good” is also presented on Table 2 along with the identified activities for achieving this improvement. In all cases the proposed period for achieving a status of “good” is 2027 with all activities yet to be progressed beyond the identification of need.
All of the watercourses have a chemical status of “Pass” with the reduction in overall status due to morphological pressures, fish barriers and water abstractions. Drawing WBAWPP002 shows SEPA’s Morphological Pressures Database within the catchment. A summary of the morphological pressures for each of the WFD waterbodies is presented in Table 3. Although the Danny Burn is not a recognised WFD waterbody, the identified morphological pressures have been appended to the table.
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Name Water Overall Abstraction Flow Morphological Pollution Proposed Proposed measures body status regulation alterations source date for id good status
Allan Water - Improve modified habitat (Source to - Remove barriers to fish passage Greenloaning) 4601 Bad Y N Y N 2027 - Reduce abstractions
Wharry Burn 4602 High N N N N na none
Lodge Burn 4603 Poor N N Y N 2027 - Remove barriers to fish passage
Muckle Burn 4604 Poor N N Y N 2027 - Remove barriers to fish passage
Bullie/Keir - Remove barriers to fish passage Burn 4605 Poor N N Y N 2027
River Knaik 4606 Poor N N Y N 2027 - Improve modified habitat
Orchill Burn 4607 Poor N N Y N 2027 - Remove barrie rs to fish passage
Allan Water - Improve modified habitat d/s of - Control abstractions Dunblane 6832 Bad Y N Y N 2027
Allan Water - Improve modified habitat (Greenloaning - Remove barriers to fish passage to Dunblane) 6833 Moderate Y N Y N 2027 - Control abstractions
Table 2: Summary of the status of the watercourses within the Allan Water catchment. Table contents based on the RBMP catchment summaries
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Watercourse Muckle Keir Burn River Lodge Wharry Orchill River Allan Allan Water Allan Water Danny Burn Knaik Burn Burn Burn (source to (Greenloaning (DS of Burn (not Greenloaning) to Dunblane) Dunblane) WFD)
WFD Status Poor Poor Poor Poor High Poor Bad Moderate Bad NA
Bridges 8 6 4 2 3 9 9 6 12 1+
Fords 0 1 0 0 0 0 0 0 0
Culverts 0 0 0 2 0 11 1 0 0 3+
Impoundments 1 0 1* 0 3 3 0 3 4 1+
Cable/pipe crossing 0 0 0 0 0 0 1 0 1 -
Bed reinforcement 0 0 0 0 0 0 0 0 0 1 / ~20m
Embankment 0 0 0 0 0 0 0 0 5 / 431m - (reinforced)
Embankment 2 / 2 / 937m 1 / 0 0 0 5 / 13 / 5598m 2 / 842m - (unreinforced) 1403m 1538m 3807m
Set back 0 0 0 0 0 15 / 0 25 / 8700m 5 / 1086m - embankments 5452m
Green reinforcing 1 / 114m 1 / 114m 0 0 0 2 / 220m 2 / 232m 3 / 449m -
Grey reinforcing 0 0 0 3nr 180m 6 / 908m -
High impact 1 / 670m 1 / 860m 0 0 0 0 2 / 6460m 0 0 - realignment
Low impact 0 0 1 / 992m 0 0 1/1044m 1 / 1850m 0 0 - realignment
Table 3: Summary of the morphological pressures within the Allan Water catchment. Figures represent the number of structures within the catchment & combined length of structure where available. Contents of table is based on SEPA’s Morphological Pressures Database. *The validity of the impoundment on the Knaik is uncertain.
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2.1.7 Water pollution levels
River pollution monitoring data has been supplied by SEPA for the Allan Water catchment. The collected data has been scored using the Biological Monitoring Work Party (BMWP) scoring system and the Average Score Per Taxon (ASPT) have also been calculated. The scoring systems are founded on the principle that the level of pollution in a river is inversely proportional to the variation of macroinvertebrates found at the survey site. A summary of the interpretations commonly accepted for BMWP scores are supplied in Table 4.
BMWP Score Category Interpretation
0 – 10 Very poor Heavily polluted
11 – 40 Poor Polluted / impacted
41 – 70 Moderate Moderately impacted
71 - 100 Good Clean but slightly impacted
> 100 Very good Unpolluted / unimpacted
Table 4: Summary of the BMWP classification system. Courtesy of Origin and development of the Biological Monitoring Working Party score system (Hawkes, 1997)
A summary of the available ASPT and BMWP scores has been generated for each sampling site within the catchment using the mean score, this summary is presented in Table 5. The ASPT and BMWP scores suggest that the Allan Water is in a very good unpolluted condition with a wide variation in macroinvertebrates throughout the catchment.
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Sampling point Mean ASPT Mean BMWP
Scouring U/S Allan confluence 6.0 132
Allan @ Milton of Panholes 6.7 149
Allan @ S Ashfield 6.6 179
Allan @ Kippenross House 6.4 160
Millstone U/S Allan confluence 6.6 157
Muckle Burn @ B8033 6.6 149
River Knaik @ Greenloaning 6.8 179
Allan U/S Knaik 6.2 179
Allan @ Blackford 6.1 112
Wharry @ Drumdruills 6.8 148
Rhynd @ Millhill Road 6.3 145
Rhynd @ Rhynd Farm 5.7 134
Allan @ Bridge of Allan 6.3 150
Allan @ Kinbuck 6.5 157
Danny U/S Allan confluence 6.9 150
Allan U/S Highland Spring 6.3 168
Allan Water U/S Blackford STW 6.6 139
Table 5: Summary of the ASPT and BMWP scores for the Allan Water catchment based on water quality monitoring data supplied by SEPA
2.2 Fisheries
The Allan Water is classified as Salmonid Waters under Directive 78/659/EEC. A Fisheries Management Plan was published in 2009 by the recently formed River Forth Fisheries Trust in Association with the Forth District Salmon Fishery Board. This plan presents the starting point from which the charitable Trust plans to proceed.
The Fisheries Management Plan provides the following description of the Allan Water:
“The River Allan has always had the potential to be a salmon and sea trout river of some note. It has however suffered greatly at the hands of man over the last 120 years and at one time had 12 mill dams on the main river between Kinbuck and Bridge of Allan to feed the textile and paper mills, with numerous others on the smaller tributaries such as the Millstane, Burnside, and Keir Burns for local meal mills.
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The Allan flows in a generally south easterly direction with its headwaters above Blackford. Much of the substrate, particularly in the feeder burns such as the Danny, Buttergask, and Ogilvy Burns, is alluvial gravel and as such is ideal habitat for salmonids. Unfortunately, the A9 between Blackford and Greenloaning was upgraded and almost every burn on the left bank of the Allan has been culverted. Access to prime spawning and nursery areas, particularly for sea trout, have thus been lost and much of the benefit of opening up Braco Falls has thus been negated. Between Blackford and Greenloaning the substrate continues to be alluvial in nature, although gravel is less obvious as the river nears Greenloaning.
Downstream of Greenloaning the river has been engineered by successive works carried out under the 1941 Land Drainage Act. These have severely degraded the habitat between Greenloaning and Ashfield as engineers sought to straighten the river channel to improve runoff; erosion is significant in this section. The four main streams which enter in this section are all significant contributors of juvenile salmon.
In 2005 an electricity generating turbine was installed at Ashfield the effects of which have not yet been quantified. Downstream of Ashfield the river assumes a completely different character as it flows over a sandstone bedrock shelf down as far as Bridge of Allan. There are only two streams which enter this section both on the left bank. The first, the Scouring Burn, is barred approximately 300m upstream from its confluence with the main river. The second, the Wharry Burn, which is a very valuable spawning burn, is barred by a natural waterfall about 1km upstream. As an aside, it is also in the headwaters of this stream at Waltersmuir Reservoir that there is a smolt facility which produces approximately 250,000 smolts per annum.
Downstream of Bridge of Allan the substrate is gravel and this forms ideal juvenile salmonids habitat right down to the point where the tidal section of the river is reached”
Table 6 summaries the pressures on fisheries on the River Allan, the table originates from the River Forth Fisheries Management Plan.
The Fisheries Management Plan identifies that the main salmonids fish run on the Allan Water is in the Autumn, however it is noted that there is a small salmon run in the summer.
Locally, the Allan Water is managed by the Allan Water Angling Improvements Association which was formed in 1911 to improve the quality of fisheries within the Allan catchment. It is reported that at the time of preparation of the Fisheries Management Plan that the Allan Water Improvement Association was preparing its own local fisheries management plan however it is understood that this plan has not yet been finalised. Nationally, the River Forth Fisheries Trust is a member of Rivers and Fisheries Trusts of Scotland (RAFTS).
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Table 6: Summary of the pressures affecting fisheries on the River Allan, the table has been lifted directly from the River Allan Fisheries Management Plan (River Forth Fisheries Trust, 2009)
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2.3 Hydrology and flood risk
2.3.1 Hydrometric data
There are two flow gauging stations operated by SEPA on the Allan Water as presented in Table 7. The locations of these gauges are shown on drawing WBAWPP001.
Gauge Record Median annual Maximum length flood gauged flow
Kinbuck 1951 – present 69.2m3/s observed 144.9m3/s (18001) 72.5m 3/s descriptors (Dec 2006)
Bridge of Allan 1971 – present 88.5m3/s observed 182.3m 3/s (18005) 83.6m3/s descriptors (Dec 2006)
Table 7: Summary of the flow gauging stations within the catchment
2.3.2 Hydrological assessment 2.3.2.1 Whole catchment analysis of median annual maximum flow and time to peak
The median annual maximum flow (QMed) and time to peak were estimated for all watercourses within the study area with a catchment area greater than 0.25km 2 using the revised QMed by catchment descriptors methodology. The results of the QMed analysis are shown in WBAWPP010. Some key findings of this analysis are presented in Table 8.
Catchment Time to peak QMed (hrs) (cumecs)
Allan at confluence with Knaik 5.2 18
Knaik at confluence with Allan 4.4 42
Keir at confluence with Allan 4.6 16
Muckle at confluence with Allan 4.0 20
Lodge at confluence with Allan 3.8 7.0
Allan at Kinbuck 6.4 73
Allan at Bridge of Allan 8.3 84
Allan at confluence with Forth 8.7 84
Table 8: Summary of findings of the whole catchment QMed and time to peak analysis at key locations within the catchment
The whole catchment analysis of the median maximum annual flow and time to peak based on catchment descriptors suggests that at their confluence near Greenloaning the River Knaik is considerably more flashy than the Allan Water. Of note, the Keir Burn at Greenloaning produces flood flows almost as big as those on the apparently larger Allan Water, while the Muckle Burn, which meets the Allan Water a short distance downstream, produces larger flood flows.
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Further details of the method used to derive QMed and time to peak for the whole catchment is provided in Appendix A. 2.3.2.2 Single site analysis of gauged sites
A hydrological analysis of the Allan Water at Bridge of Allan was undertaken as part of the Allan Water Flood Mapping Study by Halcrow for Stirling Council and is reported in Allan Water Flood Mapping Stage 3 (Halcrow, 2009). This study was based on an earlier hydrological assessment undertaken in 2006 and used flow data between 1971 and 2006. It is should be noted that the relatively large flood in 2008 was not included within the assessment as it was an incomplete water year at the time of the revised study. The 2007 water year was not included in the revision of the study as it had an annual maximum of marginally less than the calculated median annual maximum flow and hence would have a small impact on the outcome of the analysis. During this previous study it was identified that a pooled analysis produced a flatter flood growth curve, hence it is proposed not to undertake a pooled analysis as part of this study.
A revised single site analysis has been undertaken for the Kinbuck and Bridge of Allan flow gauges. The results of the analysis are presented in Table 9.
Flood Allan Water Allan Water Allan Water Allan Water return Bridge of at Bridge of at Kinbuck at Kinbuck period Allan growth Allan growth (cumecs) (yrs) factor (cumecs) factor
2 0.940 83 0.992 69
10 1.505 132 1.443 100
50 2.156 190 2.013 139
100 2.486 219 2.320 161
200 2.852 251 2.674 185
1000 4.117 362 3.720 257
Table 9: Summary of the single site hydrological analysis
The Kinbuck gauge has a longer flow record than the Bridge of Allan gauge and therefore the analysis at Kinbuck is less influenced by the relatively large floods which were experienced on the Allan Water in 2006 and 2008. Hence the analysis of the Kinbuck gauge indicates a shallower growth curve than that identified for the Bridge of Allan. 2.3.2.3 Baseline assessment using the Soil Conservation Service Runoff Curve Number methodology
To develop a better understanding of how flood flows are generated across the catchment an alternative hydrological assessment has been undertaken using the Runoff Curve Number methodology which is reported in Urban Hydrology for Small Watersheds TR-55 (USDA, 1986). This methodology was developed by the Soil Conservation Service (SCS) in order to facilitate the hydrological assessment of catchments in North America which were undergoing land use change, principally urbanisation. In this study it is planned to use the principles of the
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methodology to quantify the effects of natural flood management. Given that the method was not developed for use in Scotland it is necessary to introduce some variations, namely:
• The derivation of input precipitation - estimated using the Flood Estimation Handbook’s Depth Duration Frequency model
• Classification of soil types – estimated using Hydrology of Soil Types data
To keep the findings of the study in context the results of the alternative analysis using the Soil Conservation Service Runoff Curve Number assessment will be used to scale flows generated using the generally accepted Flood Estimation Handbook methods.
In this study the methodology has been applied using a 25m grid across the entire catchment using GIS, this approach has effectively divided the catchment into a large number (345,600) 25m by 25m sub-catchments. The runoff from each sub-catchment has been calculated based on the SCS Runoff Curve Number methodology taking account of precipitation, ground cover, soil type and ground slope. A flow routing model, developed using the methodology presented in TR-55, was constructed using GIS. This flow routing model assessed flow velocities of the generated runoff on its journey from the sub-catchment to the catchment outlet by assessing sheet flow, shallow concentrated flow and channel flow (including allowances for floodplain flow). The results of the flow routing analysis enabled the time to outlet to be calculated for each grid cell (or sub- catchment) thus facilitating the identification of gird cells (or sub-catchments) which contribute most to the flood hydrograph peak.
Full details of the application of the Soil Conservation Service Runoff Curve Number methodology have been provided in Appendix A.
A comparison of the results generated using the SCS Runoff Curve Number hydrological method against the FEH Single Site, IH124, FEH Rainfall-Runoff and Revitalised Flood Hydrograph Method for the Bridge of Allan and Kinbuck gauges are presented in Figure 1 and Figure 2.
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Flood growth curve Allan Water @ Bridge of Allan 450 FEH single site 400
350 SCS baseline catchment 16hr storm 300 FEH single site using Kinbuck growth curve 250 ReFH-RR 200 IH124 150
100 FEH-RR Peak discharge Peak (cumecs) discharge
50
0 1 10 100 1000 Return period (years)
Figure 1: Comparison of the FEH Single Site analysis and the SCS Runoff Curve based analysis for the Bridge of Allan gauge
Flood growth curve Allan Water @ Kinbuck 400 FEH single site 350 SCS baseline 300 catchment 16hr storm 250 FEH single site using BOA growth 200 curve ReFH 150 IH124 100 Peak discharge (cumecs) Peak discharge
50 FEH-RR
0 1 10 100 1000 Return period (years)
Figure 2: Comparison of the FEH Single Site analysis and the SCS Runoff Curve based analysis for the Kinbuck gauge
A comparison of the flood growth curves generated using the SCS Runoff Curve Number (TR55) methodology for the Allan Water indicates that the method underpredicts the smaller flood events such as the 1 in 2 year and overpredicts the larger less frequent flood events. In the region of the 1 in 50 year flood event, which is the frequency which is thought to be responsible for most flood damages within the catchment and is approximately the onset of flooding for the more affected properties, the SCS TR55 methodology predicts similar flood magnitudes.
The variations in flood growth curve between the SCS TR55 methodology and the more accepted FEH methods is thought to be due to the following factors:
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• The assignment of a runoff curve number to peat bogs and moorland is based on a generalised approximation developed as part of this study. It is noted that the assigned runoff curve number is thought to underpredict runoff for less intense rainfall events. Future studies should review the TR55 assumption of the catchment being dry at the start of flood events with the initial precipitation being intercepted prior to the generation of runoff. This could serve to increase the magnitude of the smaller more frequent flood events.
• It is accepted that there is limited experience of the application of the SCS TR55 method in Scotland and in the UK generally. Its application to the Allan Water catchment has involved a learning process and as a consequence inappropriate runoff curve numbers may have been assigned to some land use types within the catchment. Further work to calibrate the generation of runoff through calibration of the runoff curve numbers could be undertaken.
• The SCS TR55 methodology identified that a 16 hour storm was critical for the generation of flood events on the Allan Water catchment. This was found to show good correlation with the predictions of the FEH Rainfall- Runoff Methodology which identified a 16.5 hour critical storm and slightly shorter than that predicted by the Revitalised Flood Hydrograph Methodology of 20.5 hours. The recalibration of the flow routing model to reduce the time of peak for the catchment would serve to increase the magnitude of the more frequent events while reducing the magnitude of the less frequent events.
• Soil types within the SCS model have been estimated based on the HOST 1km data set. The 1km grid is relatively coarse resulting in some large discontinuities of runoff conditions and can frequently result in narrow pockets of soil types being lost, such as the relatively free draining alluvial soils. The omission of these soils will result in a tendency to overestimate the volume of runoff from the catchment for all events.
• Finally, the applied rainfall depths did not include an allowance for the Areal Reduction Factor which could reduce flows by approximately 7% for a catchment of this size.
2.3.3 Flood mapping
A range of flood maps within the catchment have been made available to this study as detailed below:
• Second Generation Indicative Flood Map for the 1 in 100yr, 1 in 200yr and 1 in 1000yr (SEPA, 2006) covering the entire extent of the catchment
• Flood mapping in Bridge of Allan for a range of flood events (Halcrow/Stirling Council, 2008)
• Flood mapping in Greenloaning for a range of flood events (Halcrow/Perth and Kinross Council, 2010)
These flood maps have been amalgamated to form a single flood map across the catchment. The combined flood extent map for the catchment for the 100yr,
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200yr and 1000yr flood events are shown on drawing WBAWPP012, where available the 50yr flood event is also shown.
A spatial database of properties at risk of flooding (up to 1 in 1000yr flood event) was created using Ordnance Survey Master Map data. These properties were manually classified as either residential or commercial using Google Street View. Where the only source of flood mapping was the Indicative Flood Map the inclusion of properties within the flooding database was reality checked so as to remove properties which are unlikely to be at flood risk due to being situated on locally raised ground.
The flood mapping exercise identified that 356 properties are at risk during the 1 in 200yr flood event, a full summary of the estimated number of properties at risk of flooding within the catchment has been provided in Table 10. A breakdown of the property types has been provided in Table 11.
Location Properties Properties Properties Properties flooded in flooded in flooded in flooded in 50yr event 100yr 200yr 1000yr event event event
Blackford (unknown) 20 29 31
Braco (unknown) 69 76 83
Greenloaning 0 11 17 22
Kinbuck (unknown) 4 4 5
Ashfield (unknown) 3 8 10
Dunblane (unknown) 27 32 41
Bridge of Allan 96 124 190 710
Total 96 258 356 902
Table 10: Breakdown summary of the properties at risk of flooding within the Allan Water catchment by town for a range of flood return periods
Location Number of properties
Residential 879
Industrial/commercial 25
School 1
Total 902
Table 11: Breakdown of flood risk properties within the Allan Water catchment by type
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2.3.4 Aerial photographs of 2006 flood event
The 2006 flood event is the largest recorded flood event on Allan Water at both the Kinbuck and Bridge of Allan flow gauging stations. The flood peak at both gauges occurred in the early hours of 13 December 2006 with the Kinbuck gauge suggesting flows in the region of 144cumecs and the Bridge of Allan in the region of 182cumecs suggesting a flood return period of approximately 1 in 50 year. SEPA undertook an aerial photographic survey the morning after the flooding to record the extents of flood inundation, it should be noted that this was a number of hours after the flood peak. A selection of the available photographs are provided below, it is recommended that these are viewed in conjunction with drawing WBAWPP012 which shows the available flood mapping for the catchment. In many areas of the catchment the smallest flood event that has been mapped is the 1 in 100yr flood, therefore in conjunction with the photographs not being taken at the time of the flood peak it is not possible to make a direct comparison between the maps and the photographs.
Figure 3: Aerial photograph taken by SEPA of the Upper and Lower Rhynd during the receding limb of the 2006 flood hydrograph. The photograph suggests significant areas of ponding in the relatively flat areas to the north.
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Figure 4: Aerial photograph taken by SEPA of the confluence of the Knaik and Allan during the receding limb of the 2006 flood hydrograph. The photograph shows floodwater being impounded by the flood embankments and road.
Figure 5: Aerial photograph taken by SEPA of the Allan Water downstream of Greenloaning during the receding limb of the 2006 flood hydrograph. The photograph shows that large areas of the flood plain were flooded despite the presence of flood embankments and that the patterns are similar, but less extensive, to the available 1 in 100yr flood map.
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Figure 6: Aerial photograph taken by SEPA of the Allan Water at the confluence of the Muckle Burn during the receding limb of the 2006 flood hydrograph. The photograph shows that large areas of the flood plain were flooded despite the presence of flood embankments and that the patterns are similar, but less extensive, to the available 1 in 100yr flood map. It is noted that the embankments along the Muckle Burn are serving to create an obstruction to flow on the Allan thus serving to increase upstream storage but protect land, and reduce flood storage, downstream.
Figure 7: Aerial photograph taken by SEPA of the Allan Water downstream of the Muckle Burn during the receding limb of the 2006 flood hydrograph. The photograph shows that large areas of the floodplain were flooded despite the presence of flood embankments and that the patterns are similar, but less extensive, to the available 1 in 100yr flood map.
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Figure 8: Aerial photograph taken by SEPA of the Allan Water upstream of Kinbuck during the receding limb of the 2006 flood hydrograph. The photograph shows that large areas of the floodplain were flooded despite the presence of flood embankments and that the patterns are similar, but less extensive, to the available 1 in 100yr flood map.
Figure 9: Aerial photograph taken by SEPA of the Allan Water in the vicinity of the Kinbuck gauge during the receding limb of the 2006 flood hydrograph. The photograph shows that large areas of the floodplain were flooded despite the presence of flood embankments and that the patterns are similar, but less extensive, to the available 1 in 100yr flood map.
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Figure 10: Aerial photograph taken by SEPA of the Allan Water at Kinbuck during the receding limb of the 2006 flood hydrograph. The photograph shows that large areas of the floodplain were flooded and that the patterns are similar, but less extensive, to the available 1 in 100yr flood map. The photograph does not show any evidence of flooding to properties.
Figure 11: Aerial photograph taken by SEPA of the Allan Water at Ashfield during the receding limb of the 2006 flood hydrograph. The photograph does not show any evidence of flooding to properties.
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Figure 12: Aerial photograph taken by SEPA of the Allan Water at Bride of Allan during the receding limb of the 2006 flood hydrograph. The photograph shows that large areas of the floodplain were flooded despite the presence of flood embankments and that the patterns are similar, but less extensive, to the available 1 in 50yr flood map.
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2.4 Historic mapping
a) Roy Military Map
The Roy Military Survey Map 1747-1755 shows a small amount of development within the catchment. An extract of the Roy map has been provided in Figure 13. The following items are of note:
• The former Roman Road, at the time known as the Kings Road, is an important route through the catchment
• The Stirling-Perth railway line has not been constructed (understood to have been constructed in1848)
• There is no equivalent route to the modern A9 north of Greenloaning
• There is limited evidence of the construction of flood embankments anywhere along the Allan Water
• Upstream of Greenloaning the Allan Water is shown as having a meandering plan form
• Downstream of Braco the River Knaik is shown as being braided
• The lochs at Carsebreck are not shown
Figure 13: Extract of Roy Military Survey Map 1747-1755, courtesy of the National Library of Scotland
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b) Ordnance Survey Six-Inch First Edition 1863
By the time of the First Edition Ordnance Survey in 1863 the catchment has taken on many similarities to today. An extract of the first edition Ordnance Survey map has been supplied in Figure 14. The following items are of note:
• The Allan Water upstream of Greenloaning has been straightened
• The Stirling-Perth railway line has been constructed (understood to have been constructed in1848)
• The Allan Water between Kinbuck and Greenloaning is shown as having embankments along its length
• The Keir Burn has been straightened downstream of Braco
• The River Knaik is shown as being straightened with no braiding downstream of Braco
• A number of water powered mills with associated weirs are shown along the length of the Allan Water
• There is only one loch at Carsebreck
Figure 14: Extract of the Ordnance Survey 1863 First Edition, courtesy of the National Library of Scotland
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2.5 Strathallan wader surveys
RSPB has supplied the project with population data during the period of 1990 to 2009 for five species of wader within the Strathallan area:
• Lapwing (Figure 16)
• Oystercatcher (Figure 17)
• Redshank (Figure 18)
• Curelew (Figure 19)
• Snipe (Figure 20)
All these species rely, to a varying degree, on a high water table in pasture which has appropriate grazing.
The data is for fields covered in every year of the survey and represents densities of each species for the whole Strathallan area relative to the densities elsewhere in Scotland. Due to foot and mouth restrictions survey data is not available for 2001. At this time more specific data for regions or fields is not available. The data show large declines which are anecdotally thought to be as a consequence of changes in the management of grazing land. As yet there has been no formal work done to identify reasons for the alarming trends. The data was collected by Dr Mike Bell, formerly from Stirling University, and has been reproduced with his kind permission.
Figure 15: Field surveys of wading birds during the period of 1990 to 2009 by Professor Mike Bell
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40
35 )
-2 30
25
20
15
10 Density of lapwing (pairs lapwing ofkm (pairs Density
5
0 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 Year
Figure 16: Density of lapwing in Strathallan (comprising Mid Cambushinnie, Nether Cambushinnie, Naggyfold, Loig, Greenloaning, Ardoch Carsebreck, Kinpauch, Bardrill and Tigh na Blair), 1990-2009. The horizontal lines (from top to bottom) represent the density at which the site would qualify among the top 1%, 2%, 5%, 10% and 20% of Scottish lowland farmland site for this species.
12
10
8
6
4
2
0 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 Y ear
Figure 17: Density of oystercatcher in Strathallan (comprising Mid Cambushinnie, Nether Cambushinnie, Naggyfold, Loig, Greenloaning, Ardoch Carsebreck, Kinpauch, Bardrill and Tigh na Blair), 1990-2009. The horizontal lines (from top to bottom) represent the density at which the site would qualify among the top 1%, 2%, 5%, 10% and 20% of Scottish lowland farmland site for this species.
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5
4
3
2
1
0 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 Year
Figure 18: Density of redshank in Strathallan (comprising Mid Cambushinnie, Nether Cambushinnie, Naggyfold, Loig, Greenloaning, Ardoch Carsebreck, Kinpauch, Bardrill and Tigh na Blair), 1990-2009. The horizontal lines (from top to bottom) represent the density at which the site would qualify among the top 1%, 2%, 5% and 10% of Scottish lowland farmland site for this species.
8
7 )
-2 6
5
4
3
2 Density of curlew curlew of(pairs km Density
1
0 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 Year
Figure 19: Density of curlew in Strathallan (comprising Mid Cambushinnie, Nether Cambushinnie, Naggyfold, Loig, Greenloaning, Ardoch Carsebreck, Kinpauch, Bardrill and Tigh na Blair), 1990-2009. The horizontal lines (from top to bottom) represent the density at which the site would qualify among the top 1%, 2%, 5%, 10% and 20% of Scottish lowland farmland site for this species.
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7
6
5
4
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1
0 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 Year
Figure 20: Density of snipe in Strathallan (comprising Mid Cambushinnie, Nether Cambushinnie, Naggyfold, Loig, Greenloaning, Ardoch Carsebreck, Kinpauch, Bardrill and Tigh na Blair), 1990-2009. The horizontal lines (from top to bottom) represent the density at which the site would qualify among the top 1%, 2%, 5%, 10% and 20% of Scottish lowland farmland site for this species.
2.6 Integrated Habitat Network
Draft Integrated Habitat Network data has been made available to the project for the Central Scotland Green Network region by Forestry Commission Scotland via Scottish Natural Heritage. Unfortunately this region does not cover the entire of the Allan Water catchment, with the Perth and Kinross area of the catchment being outside this region. The network identities three broad categories of Priority Enhancement Areas:
• Woodland
• Wetland
• Grassland
As the data is currently in a draft state it has been supplied in low resolution raster format which is not of sufficient quality to allow the specifics of the data to be realised. Figure 21 shows an extract of the available Integrated Habitat Network Data. Despite the relatively low resolution it is still possible to identify the general trends within the data.
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Figure 21: Draft Integrated Habitat Network data supplied by SNH
When this data set is released it will form a valuable tool for matching natural flood management measures with habitat creation by enabling measures to form part of a larger regional habitat network. Through the alignment of projects with the Priority Enhancement Areas identified in the Integrated Habitat Network data it may be possible to make better use of environmental enhancement funding streams such as the Scottish Rural Development Programme (SRDP).
It should be noted that the Project does have access to the Potential Native Woodland Network (Forestry Commission Scotland). This data has been produced in a similar fashion to the Integrated Habitat Network however it identifies different native forest generation potential. The Potential Native Woodland Network for the Allan Water catchment is shown on drawings WBAWPP016 to WBAWPP019. Alignment of restoration activities with the opportunities within this dataset will help deliver greater biological benefits and will improve funding prospects.
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2.7 Catchment reconnaissance survey
Extensive proportions of the streams and rivers within the Allan water catchment have been impacted by management activities. Principally these include straightening and/or canalisation of the mainstems of the river on the floodplain, and deforestation and heavy grazing of the riparian zone across the catchment. As such significant potential exists for river natural flood management projects to be undertaken.
2.7.1 Summary of survey extent and detail
A reconnaissance level survey of approximately 30km of river channel was completed for reaches across the Allan Water catchment, in late March and April 2011. The survey covered key sections of the Allan Water, Muckle Burn, Keir Burn, River Knaik, Danny Burn, Ogilvie Burn and Wharry Burn. Details of the survey including the 9 survey reaches are shown in Table 12.
Survey Water Downstream Upstream Stream course extent extent length
Section 1 Allan Mid-Cambushinnie Road bridge at 6.5km Water Farm Greenloaning 280581 705978 283508 707882
Section 2 Allan Road bridge at Milton of Panholes 6km Water Greenloaning near Blackford 283508 707882 289017 709491
Section 3 Wharry Kippenrait Glen Road Bridge on 3km burn 279304 699553 Sherrif Muir 282655 70536
Section 4 Muckle Confluence with Knoxfauld farm 1.5km Burn the Allan Water 280589 707505 281847 706635
Section 5 Muckle Knoxfauld Farm Cambushinne 2km burn 280589 707505 278965 707668
Section 6 Kier Confluence with Nether Braco 2.5km Burn the Allan Water 283195 710371 283478
Section 7 River Road bridge at Braco Bridge 2.3km Knaik Greenloaning 283786 709900 283508 707882
Section 8 Ogilvie A9 Culvert at Easter 3km Burn 289048 708439 Biggs 287319 706606
Section 9 Allan Mid-Cambushinnie Road bridge at 6.5km Water Farm Greenloaning 280581 705978 283508 707882
Table 12: Summary details for each section of the river reconnaissance survey
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The survey identified important geomorphological features and fluvial processes that have helped guide the development of NFM proposals. Specifically, focus of the survey included:
i) Geomorphic character and ‘reach type’
ii) Sediment transport processes
iii) Riparian status
iv) Status of instream habitats
v) Evidence of instream engineering
vi) Barriers to restoration activity
Survey methods and rationale together with a more detailed discussion of the results are presented in Appendix B of this report.
2.7.2 Summary of each surveyed section 2.7.2.1 Section 1: The Allan Water from Mid Cambushinnie to Greenloaning.
The Allan water through this section has been extensively re-profiled and embanked. The channel can be described as ‘passive meandering’ in character. It is clear following the cessation of dredging, that the relatively low gradient and cohesive floodplain material results in limited development of hydromorphological features (e.g. point bars, gravel islands). A few, more active, locations associated with confluences or tight meanders are exceptions, but do introduce some habitat diversity. The capacity for process driven development of both instream and riparian physical habitat diversity is likely to be limited. The simplified morphology of the riverbanks and floodplain margins, and significant absence of riverbank woodland has reduced fluvial-terrestrial interactions that can result in erosion and deposition processes. The erosion, transport and deposition of sediments, both instream and within the riparian zone, are key to the natural recovery of river channels.
Twentieth century management of the channel, including dredging and embankment construction, was evident throughout the reach. Together with the earlier geomorphological history of the valley, this is thought to have contributed to the relatively entrenched morphology of the river through this section. The resulting reduced connection with the floodplain has limited natural riparian development. However, given the entrenched cross-sectional profile, lateral connections would prove difficult to restore. It is also expected that attempts to restore floodplain connection and associated processes by raising bed levels and removing embankments would be met with considerable resistance from stakeholders. Objections include significant disturbance to instream salmonid habitat and constraints that it would impose on land management, which has developed in accordance with the reduced level of flooding (e.g. recent reductions in farm size have been possible in part due to the productivity of the land). 2.7.2.2 Section 2: The Allan Water from Greenloaning to Milton of Panholes
The Allan water though this section has been extensively modified and managed. Both cross-sectional morphology and planform have been altered significantly
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affecting both hydrological and fluvial processes. Sediment erosion and deposition is evident from the geomorphic features present in the upstream reach of the section where there is more space within the channel for adjustment. However, the fluvial processes along the majority of the section length have been significantly constrained by the channel geometry and historic management. The absence of any riparian vegetation structure further simplifies the hydraulics and consequently, the fluvial processes. The river in this section, although higher in gradient than section 1, is considerably smaller and natural development of a diverse geomorphic habitat will be limited by both low stream power and low sediment supply. A return to a highly sinuous planform, as is discernable on aerial photographs, would require management interventions in the form of instream structures or large-scale planform restoration.
Currently the homogeneous instream habitat provides extensive niche space for spawning and juvenile salmonids rather than supporting a range of ecological functions. In addition to limiting its ecological value the lack of physical diversity makes the habitat more resistant to development and less resilient to habitat deterioration.
The floodplain varies along the length of the section with implications for the type of restoration and natural flood management projects that will be possible. Floodplain for the first 1000m downstream from Blackford is relatively well- drained land. The Subsequent ~500m is very marshy, partly because of the raised elevation of Carsebreck Loch and partly due to embankments along the Allan Water preventing drainage. Standing water is present for much of the year and remeandering through this section may significantly alter the wetland habitat present. The section of river past Carsebreck Loch provides the first real opportunity for the restoration of natural processes and increasing floodplain connectivity, although valley floor width is constricted by the raised level of the Loch which may present an unacceptable risk. Downstream from this point the Allan Water flows through a wider section of floodplain where reinstatement of a meandering planform would increase connectivity. This section provides perhaps the greatest opportunity for river and floodplain restoration at the ecosystem level. 2.7.2.3 Section 3: The Wharry Burn
Sections of the Wharry Burn were surveyed above and below the fish farm (approximately 3km in total). Where the river flows through Kippenrait glen the riparian zone has a complex vegetation structure with woodland cover along both banks. The lateral extent of the zone is limited by the steep valley sides. A high density of complex large woody debris structures indicates the potential for instream wood to slow the flow of water. This section has some potential to serve as a reference site for natural flood management activities on other tributaries of the Allan Water, with regard to the density and complexity of the riparian woodland and the function of woody debris.
Upstream of the reservoir the Wharry Burn is has been impacted by the removal of riparian woodland. The restoration of natural river processes through these reaches is unlikely to have much flood management value because of the expected flow attenuation within the reservoir.
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2.7.2.4 Section 4: The Muckle Burn from the Allan Water to Knoxfauld
The Muckle Burn changes in character round 1.5km from the confluence with the Allan Water and is considered here in two sections. Section 4, below this point and the section 5 above.
From the Allan Water to the Bridge of the B8033, both the planform and cross- sectional profile of the river have been modified. As with other sections, fluvial processes are limited, especially in the straightened reaches where sediment deposition is restricted to very small patches. Attempts to prevent channel adjustment are evident at a number of locations. These include wooden stakes, and reinforcement of the bank toe with boulders. Instream engineering was observed in this section in the form of a moderate size weir. Recent repairs to the embankment have prevented the river from bypassing this structure. A smaller concrete weir, apparently constructed to protect a utility pipe, was also present.
Planted trees on the margins of the floodplain remain disconnected, as the channel is very entrenched, through the reaches below the road bridge. The stream is confined with steep banks that would complicate efforts to plant trees at the waters edge. Above the bridge there are relicts of a masonry structure and a crossing point for a high pressure gas pipeline (under the bed of the channel). NFM projects aimed at this section would have to be carefully considered as the infrastructure present would complicate planning and design considerably. 2.7.2.5 Section 5: The Muckle Burn from Knoxfauld to Cambushinnie
This Section has a riffle-pool morphology with sections of bedrock. Approximately a third of the surveyed length has relatively dense riparian woodland along at least one bank. There are extensive aquatic-terrestrial interactions including tree roots creating habitat along the channel margins and significant input of large woody debris. Fluvial processes are evident in the form of multiple channel sections and sediment deposition creating physically diverse gravel point and side bars. The riparian reaches demonstrate the potential of a complex riparian structure to introduce physical habitat diversity, although channel slope and bedrock are additionally important factors. Upstream of the woodland section livestock grazing to the channel edge limits the potential for the natural development of a complex riparian zone. The riffle-pool morphology continues although morphological units are more widely spaced. There is evidently potential for natural flood management measures. The cross-sectional profile of these upper reaches is relatively natural and the frequency of connection to the floodplain could easily be increased with the addition of woody debris. Additionally, floodplain roughness could be increased by planting riparian woodland on the relatively constrained but low lying valley floor. 2.7.2.6 Section 6: Keir Burn from the River Allan to Nether Braco
The lowermost reaches of the surveyed Section of Keir Burn have been heavily modified. The channel has been reprofiled and straightened for approximately 1km along the edge of the A822 from Greenloaning to Braco. Habitat is presently limited by the high embankments and heavy grazing, along much of the reach. Although flow appears relatively diverse at the mesoscale, the lack of a diversity of geomorphic features makes habitat relatively homogeneous at the reach scale. Opportunities for sediment deposition are highly limited and it is expected that
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high water velocities across the full channel width, during floods, are likely to convey sediment straight through the reach. Evidence of channel adjustment and attempts at maintenance were clear in the survey although multiple breach points in the embankment suggest efforts have been reduced more recently. Restoration of a more natural morphology may provide the opportunity to reduce risk to infrastructure and the need for ongoing management but may take up a significant proportion of Keirallan Farm land. Although the natural course is not clear, design could be informed through hydromorphological modelling or through further investigations into historic maps and the existing LiDAR. The presence of electricity transmission lines in the vicinity would complicate the design process.
Modification of the river continues behind Keirallan House, although reduced grazing pressure and riparian trees provide some habitat diversity. Riparian fencing, additional riparian planting and mature trees around Grinnan Hill are also present although instream habitat remains constrained by the lack room to adjust within the riparian corridor. Upstream of the B8033 road bridge extensive woodland cover and a relative absence of grazing pressure have allowed a relatively diverse habitat to be maintained. A clear riffle-pool morphology and additional habitat complexity introduced by outcrops of bedrock means this section is distinct from the morphology that would be appropriate for a natural flood management project o the lower reaches. 2.7.2.7 Section 7: River Knaik from Greenloaning to Braco Bridge
The River Knaik through this section has been heavily modified and canalised. As with sections surveyed on the Allan Water, modifications to the cross- sectional profile have severely reduced habitat diversity and limited fluvial processes. The river is showing some signs of process driven recovery with the erosion and deposition of sediment introducing habitat heterogeneity. This development is supported by the combination of hydrology and slope that produce higher stream power relative to the Allan Water in Section 2. However habitat diversity remains low relative to the potential levels, but conditions are particularly suitable for salmon spawning, providing some of the best habitat in the Allan Water system. Gravel bars present are generally small and relatively simple with regard to both structure and substrate. Likewise, the limited geomorphic activity within the riparian zone means this habitat remains simple, limiting ecological processes.
Existing infrastructure requires careful consideration for this Section. The course of the roman road crosses the river south of Braco and potential archaeological remains were evident on the riverbank. Modifications to the riverbank, including a stretch of stone filled gabion baskets designed to protect underground utilities were also present. Consultation with Scottish Water in June identified that a large diameter water main runs along much of the left bank of this reach. A sewage treatment works has also been constructed on former floodplain land. Electricity pylons have been erected along 500m of riverbank as it passes behind Braco. The same stretch has residential properties with gardens up to the waters edge. The lower 500m of this section reportedly floods already with the embankments serving to retain floodwaters. Combined, these factors present a significant barrier to planform restoration and floodplain reconnection.
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The relatively dynamic nature of the River Knaik has the potential to create management challenges in the future as its current character is inconsistent with the ongoing fluvial processes. Although restoration may, in the long term, be the only sustainable solution, efforts might be better directed at locations where greater habitat and flood management benefits can be achieved under less complex and economically constraining circumstances. 2.7.2.8 Section 8: The Ogilvie Burn from the A9 to Easter Biggs
A number of tributaries to the Allan Water flowing in from the Ochils are similar in character and condition. The Ogilvie Burn was one of two chosen for survey. The morphology of the stream is only moderately impacted, however heavy grazing and removal of the riparian zone have reduce habitat quality and present NFM opportunities. In the lower reaches the river is heavily grazed to the waters edge resulting in a very simple riparian structure for much of the length. Instream morphology is more diverse and has a riffle-pool morphology. Planform adjustment has resulted in occasional island features and introduced an element of diversity to sections of floodplain. The river has a constrained floodplain with the river valley having eroded below the level of the wider landscape. The steepness of the channel slope and relatively small valley width reduce options for floodplain storage. However, it is evident that the stream frequently overtops its banks indicating potential for increasing floodplain roughness through riparian and valley floor planting.
Sections of wooded valley upstream indicated the importance of riparian fencing. Although woodland exists to the channel edge, grazing has limited the development of an understorey and there appears to be limited woody debris on the forest floor and few mature trees. Riparian planting as an NFM measure and as a sustainable source of instream wood, will require an appropriate management strategy if maximum flood management potential is to be realised. 2.7.2.9 Section 9: The Danny Burn from the A9 to Whaick
The Danny Burn catchment is managed on behalf of Highland Spring who are vary conservative in their approach to ensure the protection of their bottle water sources. As with the Ogilvie burn, much of the Burn flows within a river valley that has eroded below the level of the wider landscape providing a constrained floodplain with limited storage potential. Again natural flood management may be possible by increasing the roughness and reducing flow across the valley floor which is well connected to the river. The potential increase in channel habitat complexity that riparian woodland can provide is demonstrated in a conifer plantation near Burnside where large woody debris and extensive gravel deposition have resulted in multiple channels and instream flow complexity.
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2.8 Summary of catchment characteristics
The desk based analysis and catchment reconnaissance survey has identified that the Allan Water is exposed to a wide range of pressures that result in the catchment being in an unfavourable condition both hydrologically and environmentally. These unfavourable conditions are having a noticeable impact on the lives of people. From an initial overview the catchment is in a comparable condition to many other typical catchments in the lowlands of Scotland. Further to this strong ASPT and BMWP scores together with the knowledge of the comparatively low intensity land uses would lead to an assumption that the catchment would be in a good condition both ecologically and hydrologically however this is not case.
The pressure for increased land for agricultural production has resulted in many reaches in the lower catchment being canalised, realigned or embanked. This has resulted in reduction in connectivity between the watercourses and the floodplain with resultant detrimental impacts to the attenuation of flood flows and reduced morphological activity, leading to subsequent knock-on impacts to both terrestrial and aquatic biota.
The land use pressures extend into the catchment headwaters with muirburn and drainage grips being commonplace to facilitate the raising of game birds and a relatively high density of sheep. In many instances upland watercourses are devoid of riparian vegetation due to the absence of riparian fencing. Together these pressures in the upper catchment are anticipated to result in an acceleration of runoff from the catchment’s headwaters.
Further pressures have been introduced because of key items of transport infrastructure that pass through the catchment including the A9 trunk road, the Stirling-Perth railway line and numerous utility lines. The disproportionate density of national infrastructure is likely to be a consequence of the catchment presenting the easiest route between the developed floodplains of the Tay and the Forth. Finally, the catchment has historically been heavily exploited for hydropower thanks to its reliable large flow of water with a comparatively steep bed slope even in its lower reaches. Together these multiple pressures all have the unfortunate effect of creating barriers to morphological processes and wildlife movement on nearly all the main tributaries of the Allan Water. These barriers have the combined effect of seriously reducing the extent of habitat available for fish spawning despite most tributaries upstream of the barriers being in favourable condition.
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3 Landowner and community engagement
3.1 Introduction
3.1.1 Profile of interviewees
Views and opinions were canvassed from a total of 11 Allan Water stakeholders representing a spectrum of land-owner categories. Included in the survey were interviews of two upland estate owners, an estate factor, a farming manager, one small part-time farmer, one tenant farmer and a farm-based artist. Information from telephone conversations with additional farmers and businesses has also been included. Most interviewees were between 40 and 60 years old and have lived in the catchment for a number of decades. Most areas of the catchment were represented including upland areas on both sides of the Allan Water valley and sections of the valley floor.
For those surveyed, both agriculture and livestock farming, specifically sheep grazing, are important income streams, and significantly shape current land- management practices. However, few of those interviewed rely on farming production as their sole source of income. Other important income sources include European subsidies, property rental, game shooting, forestry, and commercial farming related activities.
Whilst the 10 land-managers canvassed represent a fraction of the landowners in the catchment, four represent the interests of large estates, such that the survey covered a large proportion of the catchment area. The range of views expressed during interviews and presented below, are expected to reflect the views held by other land managers who operate similar businesses within the Allan Water Catchment and face similar land management challenges.
3.2 Views and opinions
3.2.1 Land-use past and present
Information on the historical changes in land-use was provided by a number of interviewees.
Local folklore describes the area of valley floor from Kinbuck to at least as far as Greenloaning as a shallow loch or marshland. This was drained by excavating a plug of rock near Kinbuck, so that a tenth century King could recover the body of his Queen, lost whilst trying to cross a ford in bad weather. The period as a loch, is, in the opinion of one interviewee, the reason why the floodplain is so fertile, allowing a number of small farms to prosper on the Allan Water floodplain. Many of these were previously tenant farms of either the Cromlix Estate or Braco Castle Estate, that have since been sold to private owners.
Construction of the Central Scotland Railway occurred in the 1850s and is widely thought to be the reason that so much of the Allan Water has been straightened, although land drainage is likely to have been an additional goal.
A diversity of land-use types, within the Allan Water catchment, was identified during the survey. Economic interests in the upland areas of the Allan Water catchment include sheep grazing, forestry, spring-water abstraction and game
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shooting. Key lowland land-management includes grazing (predominantly sheep), arable and forestry.
Installation of drainage is extensive throughout the catchment. Tile drains, widely installed across the catchment at the beginning of the last century, still function. The majority of the valley flood is drained through a network of ditches as are typical across Lowland Scotland. The effectiveness of these historical efforts to drain the land and increase productivity was mixed and areas of wetland and bog still exist. Efforts continue with the insertion of shallow hillside surface drains to improve growing conditions for heather, maintenance of field ditches and use of mole drainage in fields.
3.2.2 Views on fluvial processes and flooding
The management of the river has a long history on the Allan water catchment and some interviewees had been involved in some form for 60 or more years. As such, they expressed strongly held opinions about the Allan Water and tributaries, developed from extensive experience of land and river management practices through the twentieth century.
Erosion and deposition, although recognized as natural processes, were considered as a problem that required management, by some interviewees. One land manager expressed concern that if left unmanaged, the river would rapidly become uncontrollable. Others recognised the importance of fluvial processes to the wider ecosystem but were concerned about loss of land having lost as much as 5m width of field margin in as many years.
An increase in the frequency of large floods on the Allan Water was widely observed by interviewees who managed lowland areas of the catchment. This was attributed to a range of factors including climate change, climate fluctuations and extensive tree planting. It is worth noting that, when discussed, interviewees referred to human induced global warming almost apologetically, and no firm belief of its validity was expressed.
Both flooding and river channel ecology were recognized as a natural process by all participants, especially those in lowland areas who were well aware that the land they farmed was an intrinsic part of the river system. However, views differed considerably on whether or not attempts should be made to control floods, and on the value of the trade-off between farming, floodplain function and biodiversity. Whilst most recognised space for all three, it was often felt that priority should be afforded to productivity.
There was a general feeling held by a number of participants that building of residential on the floodplain is unwise activity, and to some degree unethical, that should be more tightly controlled by Stirling Council.
3.2.3 Positions on flood management
Views on natural flood management varied considerably. All were aware of flooding issues in Stirling but knowledge of flood risk in villages and towns of the Allan Water Catchment was more varied. None expressed any sense of obligation to the residents of properties at flood risk. Nor did they feel natural flood management options would fit in seamlessly with existing commercial activities. In one case this was because of a strongly held belief that food
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production and local employment are more valuable land uses, especially in the current political climate.
Landowners less reliant on the land for income, mainly because of access to alternative income streams, were the most open to natural flood management suggestions. Unfortunately other constraints, identified during the interview and reconnaissance surveys, may make NFM less attractive for those locations. Constraints include increasing flood-risk to neighbouring properties and disrupting existing habitat.
Many participants were sceptical of how beneficial the implementation of natural flood management proposals would be for downstream communities. The reasons behind this widely held belief were ranged from the scale of the proposals to the characteristics of the catchment. Some felt that given the topography of the catchment measures to slow runoff from the steep hill-slopes would not result in a significant change downstream. While some were willing to consider planting woodland, they felt the area of land they could make available would be insignificant given the total area of the catchment. The lack of a strong scientific evidence base for many of the NFM measures was considered a problem by some interviewees but they appreciated the need for landscape scale trials.
The majority of participants were unaware of the Flood Risk Management (Scotland) Act.
3.2.4 Positions on river restoration
The majority of participants are of the opinion that biodiversity is a valuable component of the countryside that is worth supporting and protecting. The concept of guardianship of the environment concisely sums up the attitudes expressed by most. However, for most it was important to emphasize the point that the land still has to provide an income. Many feel they have significant biodiversity features on their farms already, for which they receive no financial support and little credit.
The concept of river restoration was well understood by most participants in the study. Some had undertaken restoration activities in the past, for example wetland habitat. However, an in-depth understanding of restoration at the ‘ecosystem-processes’ level was rare. For example, an interviewee may understand the value of restoring spawning habitat for salmon but not link this to a requirement for the reinstatement of geomorphic processes.
For some, restoring the river to a good condition was interpreted as a need for extensive management. This included mowing the banks to form a ‘protective turf’, controlling rabbit populations, grazing to keep down weeds, herbicide spraying. In some cases this was undertaken for ‘habitat conservation’ purposes. Grazing of the riverbanks by sheep is currently used by some land-managers as an effective control measure, in addition to spraying, of giant hogweed.
Participants were generally aware of the Water Framework Directive, but not necessarily of its requirements.
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3.2.5 Interest in a project on the Allan Water
The majority of participants appreciated being consulted early on in the lifespan of the project and most were interested in remaining informed of developments. All were provided with literature relating to the project, made aware of the website and supplied contact details for requesting further information. However, only a few could be considered enthusiastic in being actively involved in a project. One recognised an opportunity to be seen in a positive light by offering NFM opportunities on his land. A few were genuinely interested in helping reduce flood risk downstream suggested proposals be presented to them. There is definite interest amongst many interviewees in the possibility of receiving income for providing flood management services.
Interviewees were, on the whole, commercially astute and seemed experienced in diversifying business interests. Compensation for lost production and the cost of implementing proposed methods were frequently discussed topics.
Some participants were aware of, or had been approached previously, about a flood storage scheme on the upper reaches of the River Knaik. One interviewee suggested that this would be the only effective project for realistically achieving a significant reduction in flood risk downstream.
Many could see the value of having a trial project to test the effectiveness of Natural Flood Management although they expressed concern that returns may not be seen for many decades and that flood risk in the short term may increase, for example, if drainage was put in to support the early years of tree growth, or to allow trees to be planted in wet upland areas with very peaty soils.
Some gave the impression that they felt priorities of public funding sources were transient and that investing in natural flood management services now might not provide them with the security to plan management over the longer term.
3.2.6 SRDP rural priority funding
There is potential for Natural Flood Management to increase the number of points contributing to an SRDP. It is identified as a Regional Funding priority for both the Tayside and Forth regions (TAY19 and FOR19 respectively). By highlighting that a SRDP will have natural flood management it should improve the chances of a successful application. This was not generally known and the fund is not currently a source of income for any of the participants surveyed. One farm applied for the funding but was unsuccessful in their application. Although the application did not include reference to NFM, it is not clear how much difference this would have made. Other farms did not take part in the application process for a variety of reasons. Those offered during the interviews included:
i) Not being able to afford the consultancy fees to put together an application. Contracting a farming consultant was seen as necessary for a successful application, partly because of excessive complexity in the system. Private consultants were seen as the only option, now that support from FWAG officers is no longer made available.
ii) Failure of previous applications was taken as an indication that they would be unlikely to get the required level of points in future applications.
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Especially considering, in their experience, the fund is becoming increasingly competitive, with more points needed each year.
iii) Objection to the level of risk inherent in the scheme. The application system is widely perceived as a lottery with excessive risk of not receiving financial support making the investment of time and resources in the application process not worthwhile.
iv) Some expressed a desire to remain a farmer that farms the land, objecting to the concept of being paid to do nothing.
v) A number of interviewees were not eligible to apply for SRDP priority catchment grants. This was felt to be the case by non-farmers and by one large estate that claimed they were not eligible because they have always managed land sensitively to biodiversity and so there was not the opportunity to achieve improvements they believed to be required by the scheme.
vi) Some were concerned that taking land out of production would result in a reduction SRDP single farm payments, which are paid in proportion to the land in production.
3.3 Summary
3.3.1 Constraints and opportunities identified
It is clear from the interview processes that a vast range of factors will affect the success of developing the Allan Water as a demonstration catchment for river restoration and natural flood management. In some cases the barriers identified should be interpreted as both a need, and an opportunity, for further engagement and promotion of river restoration and natural flood management.
The lack of a simple, well-structured funding stream will be important. Promoting SRDP as a mechanism for funding projects is likely to discourage farmers from getting involved as many consider the application process to be complex and unreliable.
i) In a number of cases Natural Flood Management objectives conflict with, and hence would be in direct competition with, alternative development plans for the land. This would reduce the opportunity for getting value for money on the project.
ii) Compensation for lost production is likely to be an area of contention given the negative experiences that some land owners in the area have had of compensation offers for the Beauly-Denny transmission lines.
iii) After many years of feeling that they have been underpaid, recent improvements in the outlook for farming may make farmers less interested in alternative sources of funding whilst they capitalize on improved farming profit margins.
iv) The impression that Stirling Council is in part to blame for the flood risk to properties may make it more difficult to convince landowners to undertake measures without significant support from Stirling Council.
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v) Managers do not necessarily agree with the modern approaches to river management that would be required for NFM and river restoration. It will take time and effort to convince some farmers of the value of alternatives to the long established management practices.
vi) Managers may be less likely to get involved if they do not believe in the value of the undertaking. This could be an opportunity to ensure a catchment scale network of coordinated projects and a clear plan for developing an evidence base.
vii) The increasing importance of food security and UK based production puts additional pressure on productive areas. Robust arguments for the value of NFM may be required for proposals that will result in reduced production.
viii) Some projects will require co-operation and collaboration between farmers. This may require efforts to foster new healthy relationships.
ix) The administration that may be needed for a project may in itself discourage participation. Avoiding situations that may result in overly complex planning or legal requirements would reduce the likelihood of this presenting a barrier.
x) The desire for rapid delivery of an NFM project may limit the choice of projects available as farm plans adopted by land managers tend to be developed over the long term. Conflicts with existing land-use plans would mean rapid introduction may not be achievable.
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4 Natural flood management strategy
4.1 Introduction
Based on the findings of the assessment of catchment characteristics a broad scale catchment restoration strategy has been developed to facilitate the direction of future natural flood management works within the catchment. This broad scale strategy is later developed in Section 5 as part of the identification of a suitable pilot project to commence the Allan Water natural flood management strategy.
The restoration options presented in this section are identified on the basis that all related barriers have been removed and focus on measures that will bring benefits to flood risk management.
4.2 Identification of opportunities to manage flood risk
4.2.1 Reduction of runoff
Drawing WBAWPP024 shows the anticipated key areas of runoff that contribute most to the downstream flood hydrograph peak in Bridge of Allan and Dunblane. An extract of drawing WBAWPP024 is provided in Figure 22.
Figure 22: Summary of the generation of runoff that contributes to the flood peak
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The analysis shows that the majority of runoff contributing to downstream flooding is generated in the upper Muckle, Keir and Knaik sub-catchments in the west of the catchment. The upper reaches of the Danny and Allan Water also contributing a notable amount to runoff generation. From this it can be summarised that the greatest opportunity for reducing downstream flood risk via land use change lie in these areas. Hence opportunities to reduce runoff in these areas should be most actively pursued. It should be noted that land outwith this area does have a role to play in the generation of floods and opportunities for land use changes which will reduce runoff which is remote from the identified dominant areas should not be overlooked.
4.2.2 Channel & riparian corridor restoration
Drawing WBAWPP022 shows the anticipated time to outlet for the entire catchment. In effect this shows how long it takes precipitation to travel to the catchment outlet from the point where it lands within the catchment. The results of this analysis can be used to develop an understanding of the timings of flood peaks generated by each of the sub-catchments. An extract of drawing WBAWPP022 is shown in Figure 23.
Figure 23: Summary of the estimated time to outlet for the Allan Water. Areas shown in green have a time to outlet approximately equal to the catchment mean.
The time to outlet analysis indicates that the headwaters of the Muckle Burn, a majority of the River Knaik and the upper Allan Water all have a time to peak
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that is longer than the catchment average. These areas are denoted on Figure 23 via the use of a dashed line. Based on the principles of the applied hydrological analysis it can be concluded that these area will have a significant contribution to the peak and trailing limb of the flood hydrograph at the catchment outlet. Delaying the progression of floodwater from these areas will assist in desynchronising the contributing sub-catchment flood peaks with a net effect of reducing flood risk at the catchment outlet.
Based on the results of the time to outlet analysis it can be summarised that channel restoration works which might result in the slowing of flood waters in the lower tributaries of the Allan Water, for example the Wharry and Lodge Burns, is likely to result in an increased coincidence of flood peaks. This increased coincidence of flood peaks could results in an increase in flow rates downstream and hence are likely to be counterproductive to the primary objective of reducing flood risk.
4.2.3 Floodplain reconnection
Drawing WBAWPP026 show the areas of the catchment which have the greatest potential for the attenuation of floodwater as it moves through the catchment. The potential for the attenuation of floodwater on the floodplain has been estimated through the assessment of floodplain slope. The 1 in 200yr flood extents as shown on the Second Generation Indicative Flood Map has been used to define the floodplain extent and areas with slopes of less than 1 in 200 being defined as having a good potential for flood attenuation, while those with 1 in 200 to 1 in 100 have a medium and 1 in 100 to 1 in 20 have a low potential.
As identified during the catchment reconnaissance survey, Morphological Pressures Database and landowner consultation many of the identified areas are currently disconnected due to flood embankments and incised channels. In the areas where flood embankments are present it is frequently the case that large areas of the floodplain are inundated via embankment breaches. Although flooded these inundated areas do not contribute to the conveyance of the channel therefore increasing velocities within the main channel. This concentration of flow within the channel can lead to increased channel capacity that further serves to reduce floodplain connection and accelerate the movement of floodwater through the catchment.
Before considering floodplain restoration it should be noted that increasing the provision of floodplain storage can, at least for a time in some circumstances, have a detrimental impact on flood risk via one of two mechanisms:
i) It is foreseeable that properties downstream of embankment protected areas are experiencing marginally reduced flood flows due to the constriction created by flood embankments. In effect the presence of the flood embankments causes the backing up of water upstream of the defended area. Should the flow obstructions created by the flood embankments be removed then the ability of the floodplain to convey floodwater will be increased thus removing this backwater effect storage. Without this increase in conveyance being addressed, either through a reduction in main channel capacity or roughening of the floodplain using vegetation, there is likely to be a downstream increase in flood risk.
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ii) Where attenuation is increased on a floodplain that presently floods, via roughening using vegetation or reducing the capacity of the channel to increase floodplain flow this will have a net impact of increasing local water levels during flood events. Care must be taken to ensure that the increase in water levels in the backwater generated by floodplain roughening activities does not exacerbate upstream flood risk. The shallow slopes, which offer the greatest benefits for floodplain attenuation, can also cause a backwater effect to extend a significant distance upstream.
Figure 24: Summary of areas of floodplain with greatest potential to attenuate flood flows. Green areas represent areas with good potential, light green those with medium and orange those with low.
Without any limitations the floodplain analysis has identified approximately 1.7km 2 of floodplain with good potential and 2.4km 2 of floodplain with medium potential. These areas are predominately along the main stem of the Allan Water between Ashfield and Blackford, areas that were observed to be flooded during the December 2006 flood event despite much of the area being protected by flood embankments. Away from the main area of potential floodplain restoration there are only a few pockets of medium potential with the most significant being at the top of the River Knaik.
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As discussed earlier in this section the introduction of floodplain roughening can cause backwater effects that can cause a marginal increase in upstream water levels. Great care must be taken to ensure that these backwater effects do not exacerbate upstream flood risk. As an initial screening, areas which are more than 1km downstream of potential flood risk areas, have been highlighted as being more realistic floodplain restoration opportunities, these areas are shown on Figure 24. Before progressing a specific floodplain restoration project it is important that considered hydraulic modelling is undertaken for a range of timescales so that the full impact of the works can be assessed both upstream and downstream of the site. Due to the changes in channel morphology which floodplain restoration can initiate it may also be necessary to consider changes to the channel dimensions.
4.3 Conclusion
The priorities for the Allan Water natural flood management strategy are summarised in Table 13. The level of priority has been broken down into three bands; high, medium and low, depending on the judged correlation of the measure with the assessed criteria presented in Section 4.2. The identified strategic natural flood management measures have been generalised and in many cases require considerable additional work to enable them to be progressed. Where constraints have been identified these have been presented in the table. The notable constraint of uncertain funding is present for all options however this has not been presented due to space limitations. An assessment of the WFD priority has also been assessed based on the consistency of the measures with the activities identified within the River Basin Management Plan.
As all options are at a strategic level it is not possible to provide an indication of cost. This uncertainty is due to insufficient knowledge of what the measure might actually entail, who will undertake the works, how the works would be phased, the compliance of the landowner and the conditions on site.
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Opportunity NFM WFD Type Key constraints Priority Priority
Restoration of the Allan High High Channel -Railway Water between source restoration -Multiple landowners and Greenloaning -Landowner/user interests -Environmental designations
Improved riparian High Low Channel -Wading bird population corridor on the River restoration -Landowner/user interests Knaik
Runoff reduction in High Low Runoff -Multiple land users Knaik headwaters reduction -Landowner/user interests
Runoff reduction in High Low Runoff -Access Corriebeagh headwaters reduction -Landowner/user interests
Runoff reduction in High Low Runoff -Access Arrevore headwaters reduction -Landowner/user interests
Runoff reduction in High Low Runoff -Access Muckle Burn reduction -Landowner/user interests headwaters
Runoff reduction in High Medium Runoff -Multiple land interests Danny Burn headwaters non-WFD reduction -Water abstractions -Landowner/user interests
Restoration of the Allan High Medium Channel -Multiple landowners Water downstream of restoration -High land value Dunblane including the and retreat -Landowner/user interests eventual retreat from the -Existing infrastructure floodplain -Fisheries
Control of invasive Medium Medium Channel -Sustained funding weeds on the Allan restoration
Runoff reduction in Kier Medium Low Runoff -Access Burn headwaters reduction -Landowner/user interests
Runoff reduction Meall Medium Low Runoff -Letting agreements a’ Choire Odhair reduction -Landowner/user interests
Restoration of the Knaik Medium Medium Channel -Flood risk to properties in Braco restoration -High land value -Utilities -Cultural heritage -Designed landscapes -Fisheries
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Opportunity NFM WFD Type Key constraints Priority Priority
Restoration of the lower Medium Medium Channel -Landowner interest Knaik restoration -High land value -Utilities -Landowner/user interests -Wading bird population -Fisheries
Restoration of the Allan Medium High Channel -Multiple landowners Water between restoration -Railway Greenloaning and -Wading bird population Dunblane -High land value -Potential increase in upstream flood risk -Fisheries
Restoration of the lower Medium High Channel -Landowner/user interest Keir Burn restoration -High land value -Utilities -Potential increase in upstream flood risk -Wading bird population -Fisheries
Restoration of the lower Low High Channel -Removal of flood embankments would reduce Muckle Burn restoration flow constriction on Allan -High land value -Multiple landowners & Landowner interests -Utilities -Fisheries
Improved fishpass Low High Fishpass -Land users provision for tributaries -Water user interest passing under A9
Improved fishpass Low Medium- Fishpass -Land users provision at the ‘weir’ low -Water user interest on the lower River Knaik
Runoff reductions in Low Low Runoff -Landowner/user interests Lodge and Wharry reduction headwaters
Modifications/ semi Low Low Channel -Natura2000 designations naturalisation of the restoration -Landowner/user interests outlets of the Rhynd and Carsebreck Lochs
Improved riparian Low Low Channel -Landowner/user interests corridor on the Wharry restoration Burn
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Opportunity NFM WFD Type Key constraints Priority Priority
Removal/improved Low Low Fishpass -Land users fishpass provision on the -Water user interest main limb of the Allan Water
Table 13: Summary of the generalised priorities for the Allan Water natural flood management strategy
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5 Selection of pilot project
5.1 Introduction
The pilot project selection process has been divided into three phases:
i) Initial screening of options – “long listing”
ii) Qualitative consideration of options – “short listing”
iii) Quantitative assessment of options – “ranking”
This three stage process allows an open decision making process with a clear trail of the decision made during the selection process. By using a three stage process it is possible to quickly and coherently screen off weak options prior to assessing stronger options in more detail. The screening process is founded on the findings of the broad scale strategy outlined in Section 4.
5.2 Initial screening of options – “long listing”
The initial screening of options has been undertaken through a “long listing” exercise by Halcrow-CRESS. As part of the long listing process 19 hydrologically beneficial river restoration options were identified based on the specialist judgement of the various members of the project team following the completion of the catchment reconnaissance and baseline hydrological assessment. Drawing WBAWPP014 provides an indication of the location and extent of each of the considered options. These options were then reviewed subjectively and any unviable options were rejected and the reason for the reject was recorded. A summary of the long listing process has been provided in Table 14. The options which have not been eliminated at this phase have been progressed to the short listing process for a more detailed subject appraisal.
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ID Option Progress
Moorland improvements to Muckle headwaters by reduction of stocking densities, blocking of drains and encouragement of upland 1 woodland Yes
Reduction of sheep/deer from Danny Burn catchment (aligned with water abstraction) by installation of fences. Blocking of drains and 2 encouragement of upland woodland. Yes
Naturalise lower Keir Burn plan form by manually moving channel 3 away from road Yes
No - Large number of buried services, remains of Roman Road, could increase flood risk in Braco, currently good salmon spawning habitat, close proximity to WwTW, could increase the coincidence of Allan & Knaik flood 4 Naturalise River Knaik plan form by manually creating new channel peaks
Naturalise plan form of Muckle Burn by manually creating new 5 channel Yes
Moorland improvements in Keir headwaters by reduction of stocking densities, blocking of drains and encouragement of upland 6 woodland Yes
Moorland improvements on Meall a' Choire Odhair by reduction of stocking densities, blocking of drains and encouragement of upland 7 woodland Yes
Improved riparian corridor on Knaik by installing riparian fencing, riparian/floodplain planting and reducing management of riparian 8 woodland in lower reaches Yes
Moorland improvements in Knaik headwater by reduction of stocking densities, blocking of drains and encouragement of upland 9 woodland Yes
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ID Option Progress
Moorland improvements in MOD area by reduction of stocking densities, blocking of drains and encouragement of upland 10 woodland Yes
Improvements to Allan headwaters by reduction of stocking densities, blocking of drains and encouragement of upland 11 woodland Yes
12 Floodplain planting near Ashfield and Kinbuck No -Theoretical increase in flood risk to properties upstream
Improve riparian corridor of Wharry Burn by installing riparian No - Would bring few hydrological benefits and reservoir current limits 13 fencing and riparian planting. connection to downstream
No - Floodplain is currently relatively unconnected hence option would be 14 Floodplain planting near Mid Cambushinnie of limited hydrological benefit
No - Channel is currently very incised and removing embankments would Remove flood embankments on Allan and improve riparian margin not reconnect the floodplain. Once a supply of sediments is reintroduced 15 by reinstating fences and tree planting this option would become more viable.
No - Given the proximity to the railway line, confluence with Knaik and Naturalise plan form of Allan Water near Greenloaning by manually Greenloaning WwTW it would be prudent to complete a reach further 16 creating a new channel upstream first prior to this more challenging reach.
Naturalise plan form of Allan Water near Carsebreck by manually 17 creating a new channel Yes
No – The land is very wet in this area making access potentially difficult. Naturalise plan form of Allan Water near Blackford by manually Changing the channel form could have an impact on flood risk to upstream 18 creating a new channel properties. More desirable to address Carsebreck reach first.
Cease maintenance of straightened Allan Water channel between Greenloaning and Blackford. Use strategic roughening in form of large woody debris, boulder placements and tree planting to 19 encourage change in plan form. Yes
Table 14: Summary of the long listed options considered at the outset of the option appraisal process
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5.3 Qualitative consideration of options – “short listing”
A total of 12 options have been progressed from the initial option screening process for qualitative consideration prior to the identification of a preferred pilot option. These options are listed below:
• Moorland improvements to Muckle headwaters
• Moorland improvements to Danny Burn catchment
• Restore lower reaches of Keir Burn plan form
• Restore lower reaches of Muckle Burn
• Moorland improvements in Keir headwaters
• Moorland improvements on Meall a' Choire Odhair
• Improved riparian corridor on Knaik
• Moorland improvements in Knaik headwater
• Moorland improvements in MOD area
• Improvements to Allan headwaters
• Restore Allan Water near Carsebreck
• Cease maintenance of straightened Allan Water channel between Greenloaning and Blackford
The qualitative assessment has been undertaken following the principles of Flood and Coastal Erosion Risk Management Appraisal Guidance (Environment Agency, 2010). As recommended in the above guidance appraisal summary tables (AST) have been used to record the pertinent issues associated with each of the options being considered. The AST have been included in Appendix D and Table 15, Table 16, Table 17 and Table 18 provide summaries of the qualitative assessment process.
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Option Type Number of Baseline downstream contribution to the properties 50yr flood peak at flooded Bridge of Allan during 200yr (proportion of flow event originating from or passing through area)
Moorland Land ~234 ~7% improvements to the management Muckle headwater
Moorland Land ~263 ~4% improvements to the management Danny catchment
Restore lower reaches Channel ~234 ~10% of Keir Burn restoration
Restore lower reaches Channel ~234 ~13% of Muckle Burn restoration
Moorland Land ~310 ~5% improvements to Keir management headwaters
Moorland Land ~310 ~2% improvements on Meall management a’ Choire Odhair
Improved riparian Channel ~310 ~23% corridor on Knaik restoration
Moorland Land ~310 ~10% improvements in Knaik management headwater
Moorland Land ~310 ~7% improvements in MOD management area
Improvements to Allan Land ~263 ~3% headwaters management
Restore Allan Water Channel ~234 ~21% near Carsebreck restoration
Cease maintenance of Channel ~234 ~27% straightened Allan restoration Water channel between Greenloaning and Blackford
Table 15: Summary of the flood risk management related information available at the time of the qualitative assessment options during the “short listing” process
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Option Land stakeholder benefits Land stakeholder disbenefits
Moorland Improved drought resistance for planned Reduction in grazing land improvements to the run-of-river hydro scheme Muckle headwater
Moorland Improved drought resistance and Reduction in grazing land improvements to the reduced treatment requirements for Danny catchment existing water abstractions by Highland Springs and Tullibardine Distillery
Restore lower reaches Reduced maintenance commitment Reduction in land available for farming of Keir Burn
Restore lower reaches Reduced maintenance commitment Reduction in land available for farming of Muckle Burn
Moorland Reduction in land available for farming improvements to Keir May impact viability of game shooting headwaters
Moorland Reduction in land available for farming improvements on Meall a’ Choire Odhair
Improved riparian Reduced maintenance commitment Marginal reduction in land available for corridor on Knaik farming
Moorland Reduction in land available for farming improvements in Knaik May impact viability of game shooting headwater
Moorland Reduction in land available for farming improvements in MOD May impact viability of game shooting area
Improvements to Allan Reduction in land available for farming headwaters May impact viability of game shooting
Restore Allan Water Reduced maintenance commitment Long term commitment to the reduction near Carsebreck in available farmland (albeit not currently used)
Cease maintenance of Reduced maintenance commitment Long term commitment to the reduction straightened Allan in available farmland (albeit not Water channel between currently used) Greenloaning and Blackford
Table 16: Summary of the land stakeholder related information relating to each option available at the time of the qualitative assessment options during the “short listing” process
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Option Environmental or social benefits Environmental or social disbenefits
Moorland Improved habitat for ground nesting None improvements to the birds Muckle headwater Restoration of natural landscape
Moorland Improved habitat for ground nesting Fencing may form blot on landscape and improvements to the birds reduce access for walkers Danny catchment Restoration of natural landscape
Restore lower reaches Improved aquatic habitat None of Keir Burn Restoration of natural landscape
Restore lower reaches Improved aquatic habitat None of Muckle Burn Restoration of natural landscape
Moorland Improved habitat for ground nesting None improvements to Keir birds headwaters Restoration of natural landscape
Moorland Improved habitat for ground nesting None improvements on Meall birds a’ Choire Odhair Restoration of natural landscape
Improved riparian Improved aquatic habitat None corridor on Knaik Restoration of natural landscape
Moorland Improved habitat for ground nesting None improvements in Knaik birds headwater Restoration of natural landscape
Moorland Improved habitat for ground nesting None improvements in MOD birds area Restoration of natural landscape
Improvements to Allan Improved habitat for ground nesting None headwaters birds Restoration of natural landscape
Restore Allan Water Improved aquatic habitat None near Carsebreck Restoration of natural landscape
Cease maintenance of Improved aquatic habitat None straightened Allan Restoration of natural landscape Water channel between Greenloaning and Blackford
Table 17: Summary of the environmental and social issues relating to each option available at the time of the qualitative assessment options during the “short listing” process
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Option Probable land Long term Assessed Progression to stakeholder impact on benefit-cost pilot project short acceptance flooding strength list (judgement (judgemen (judgement based) t based) based)
Moorland Reasonable Small Good Progress improvements to the Muckle headwater
Moorland Reasonable Very small Marginal Progress improvements to the Danny catchment
Restore lower reaches Marginal Small Poor Not suitable for pilot of Keir Burn (implement if opportunity arises)
Restore lower reaches Marginal Very small Poor Not suitable for pilot of Muckle Burn (implement if opportunity arises)
Moorland Marginal Very small Poor Not suitable for pilot improvements to Keir (implement if headwaters opportunity arises)
Moorland Reasonable Negligible Marginal Not suitable for pilot improvements on (implement if Meall a’ Choire opportunity arises) Odhair
Improved riparian Reasonable Small Good Progress corridor on Knaik
Moorland Marginal Very small Poor Not suitable for pilot improvements in (implement if Knaik headwater opportunity arises)
Moorland Marginal Very small Poor Not suitable for pilot improvements in MOD (implement if area opportunity arises)
Improvements to Marginal Negligible Poor Not suitable for pilot Allan headwaters (implement if opportunity arises)
Restore Allan Water Reasonable Small Marginal Not suitable for pilot near Carsebreck (implement if opportunity arises)
Cease maintenance of Marginal Small Good Progress straightened Allan Water channel between Greenloaning and Blackford
Table 18: Summary of the decision making process in selecting options to be assessed quantitatively as part of the pilot project selection process
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5.4 Quantitative assessment of options – “ranking”
5.4.1 Introduction
A total of four options have been progressed to the full quantitative assessment:
• Moorland improvements to the Muckle Burn headwaters (long listed option 1)
• Moorland improvements to the Danny Burn headwaters (long listed option 2)
• Improved riparian corridor on the River Knaik (long listed option 8)
• Cease maintenance of the straightened reach of the Allan Water between Greenloaning and Blackford (long listed option 19)
In line with the qualitative appraisal process conducted as part of the short listing process appraisal summary tables (AST) have been prepared for each of the options. The AST records all the identified factors relating to each of the options and provides a summary of the decision making process. The AST have been included in Appendix D.
5.4.2 Description of options 5.4.2.1 Moorland improvements to the Muckle Burn headwaters
This option proposes to reduce the generation of runoff within the Muckle Burn by improving the thickness of ground cover within the subcatchment’s headwaters by a reduction in stocking density. It is proposed to undertake this reduction in stocking within an area of approximately 330Ha. Overtime it is envisaged that the reduced stocking may permit the gradual recolonisation of upland woodland, which provides opportunities of ecological improvement. If desired, there is the option to accelerate the colonisation of upland woodland by the localised planting of selected whips of local provenance to provide a future supply of seed for the recolonisation of the rest of the area. In addition to a reduction in stocking it is also proposed that existing man-made drains may be blocked to reduce runoff rates from the area, this may also serve to improve shallow groundwater recharge and thus improve drought resilience.
The area of reduced stocking has not been extended to the upper area of the subcatchment to avoid interfering with the existing neighbouring wind farm. For this same reason a complete forestation of the proposed reduced stocking area has not been considered. It is envisaged that the relatively high altitude (350m), high exposure and poor soils will result in only scrubby tree species being successful in this area should the reduced stocking permit upland woodland regeneration. The poor growth of commercial timber species can be observed in the neighbouring commercial plantation to the north east which appears to suffer almost identical conditions.
It is also proposed to include approximately 2,850m (15Ha) of riparian planting as a component of this option. The inclusion of this riparian planting is thought to be partly counter productive as the headwaters of the Muckle Burn are thought to contribute to the leading limb (and peak) of the flood hydrograph at
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the downstream end of the Allan Water catchment. Thus delaying runoff from this subcatchment may serve to partially synchronise it with the hydrograph peak.
Figure 25: An example of natural woodland generation on moorland with reduced stocking
A summary of this option is shown in drawing WBAWPP016.
5.4.2.2 Moorland improvements to the Danny Burn headwaters
This option proposes to reduce the generation of runoff within the Danny Burn by improving the thickness of ground cover within the subcatchment by a reduction in stocking density over an area of approximately 780Ha. Over time it is envisaged that the reduced stocking may permit the gradual recolonisation of upland woodland, which provides opportunities of ecological improvement. If desired, there is the option to accelerate the colonisation of upland woodland by the localised planting of selected whips of appropriate local provenance to provide a future supply of seed for the recolonisation of the rest of the area. In addition to a reduction in stocking it is also proposed that existing man-made drains may be blocked to reduce runoff rates from the area, this may also serve to improve shallow groundwater recharge and thus improve drought resilience for the two water abstractions within the catchment.
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Figure 26: An example of the natural regeneration of upland woodland in an area of reduced stocking
As runoff from the subcatchment is thought to predominantly arrive after the flood peak at the downstream end of the Allan Water there is benefit to delaying runoff where possible to help desynchronise the runoff from this subcatchment with the rest of the Allan Water. The introduction of approximately 3,500m native riparian planting along the watercourses and thicker ground cover vegetation will both serve to slow runoff rates and hence assist in desynchronisation.
A summary of this option is shown in drawing WBAWPP017.
This option is aligned with the interests of local water users Highland Springs (groundwater) and Tullibardine Distillery (abstraction from Danny Water). Both these water users may be interested in the naturalisation of the Danny Water catchment through not only the improved drought resilience and improved quality of the abstracted water but also for the improvement of their brands’ images which are both centred on the untouched and pristine beauties of the Scottish highlands. A tertiary benefit for these businesses is that the implementation of natural flood management on the Danny Water may also serve to reduce flood risk to their production assets which are located in Blackford, although it should be accepted that the level of flood risk to these properties is thought to be relative low with no evidence of a previous flood history.
The improvement of access for migratory fish to the Danny Water is somewhat challenging due to a number of obstructions to fish movement including a culvert under the A9, a weir just upstream of the A9 and a number of natural barriers further upstream created by bedrock outcrops.
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Figure 27: An example of natural upland gully woodland 5.4.2.3 Improve riparian corridor on the River Knaik
This option proposes to attenuate the movement of floodwater down the River Knaik by improving the extent and quality of the existing riparian corridor. Through the increase of riparian planting and a minor modification of the maintenance regime of the existing riparian vegetation it is intended to increase the quantity of large woody debris which will serve to slow flow velocities both in channel and in the narrow out of bank floodplain zone. The option comprises approximately 18Ha of new riparian planting which will be protected for livestock in conjunction with improvements to a further 5km of existing riparian corridor.
Figure 28: Photograph showing how the upper Knaik is currently devoid of riparian woodland
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Figure 29: Photograph showing the reduced quality riparian woodland present in the middle reaches of the River Knaik
As runoff from the River Knaik subcatchment is thought to predominantly arrive in Dunblane and Bridge of Allan in the receding limb of the flood hydrograph there is benefit to delaying runoff where possible to help desynchronise flood peaks. The proposed improvements to the riparian corridor should serve to assist in improving this desynchronisation.
A summary of this option is shown in drawing WBAWPP018.
The option of improving the riparian corridor shows a strong correlation with the Potential Native Woodland Network (Forestry Commission Scotland, 2010) in extent and location. This good correlation supports the case that native woodland planting and woodland regeneration as proposed in this option would be of good ecological value to the wider locality. 5.4.2.4 Cease maintenance of the straightened reach of the Alan Water between Greenloaning and Blackford
An initial overview of the channel plan form has been assessed using the guidance contained within NRCS Stream Restoration Design Handbook (United States Department of Agriculture, 2007). A naturalised meander length was estimated to be approximately 110m and the meander wavelength was estimated to be in the region of 120m both based on a bankful channel width of 10m which was previously calculated as part of the stream power analysis. This would suggest a channel sinuosity of approximately 1.8 to 1.9 and compares favourably to the observed channel sinuosity between Greenloaning and Kinbuck of approximately 1.87 as shown in Figure 30.
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Figure 30: Figure showing a comparison of the channel length and valley length between Kinbuck and Greenloaning (data courtesy of InfoTerra via Perth and Kinross Council)
Conversely, Figure 31 shows a comparison of the channel length and valley length for an existing reach of the Allan Water alongside a suspected remnant channel. The existing reach which has been highlighted in the figure shows evidence of the development of a sinuous plan form with a measured sinuosity of approximately 1.03 while the suspected remnant channel displays a sinuosity of around 1.6.
Figure 31: Figure showing a comparison of the channel length and valley length between of an existing reach and an apparent remnant channel of the Allan Water near Blackford (data courtesy of InfoTerra via Perth and Kinross Council)
The whole catchment stream power analysis, as reported in Section 2 and presented in drawing WBAWPP011, suggest a relatively low stream power in the
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range of 10 to 50W/m 2 during an event 50% larger than median annual flood. This low energy dissipation rate may not be sufficient to re-form the channel naturally within an acceptable timeframe as a stream power of greater than approximately 100W/m 2 is required for a channel to recover its sinuosity after straightening as presented in Guidebook of applied fluvial geomorphology (Thomas Telford, 2010). However, generally channels with a power dissipation of approximately 35W/m 2 and greater are described as unstable and prone to erosion so there may be a gradual naturalisation of the channel planform.
Given the uncertainty to what extent the channel might restore itself to within a reasonable timescale once maintenance has been withdrawn it has been assumed for conservatism that the channel will reach a sinuosity of approximately 1.2.
To assist the channel in returning to a more natural form it is proposed that strategic roughening as presented in Bennett et al (2002) could be adopted. This approach is based on the considered placement of riparian planting and other roughening techniques such as the placement of boulders and large woody debris.
A summary of this option is shown in drawing WBAWPP019.
Given that the option concerns the reach of the Allan Water which is in close proximity to both the railway line and the Carsebreck Loch SSSI/ Shelforkie Moss SAC and the reliance on natural processes to shape the new channel form there are risks associated with this option should the Allan Water create a new channel in an unfavourable location. For this reason it would be prudent to employ an intensive monitoring programme in an attempt to secure a reasonable future insight into the changes going on within the watercourse and whether any of these changes may have the potential to compromise the SAC/SSSI or railway line. It may also be prudent if this option is to be progressed for a contingency plan to be in place so that heavy protection can quickly be installed if undesirable changes do take place.
Should the cessation of maintenance not be acceptable to stakeholders then option 18, the manual creation of a restored river channel reach on the Allan Water near Carsebreck Loch remains an option. It is reasonable to assume that this alternative fallback option would deliver approximately a third of the reduction in flood risk presented by the full naturalisation of the Allan Water although the benefits in flood reduction would be realised within a much shorter time frame when compared to the multi decade scale that would be required for the cessation of maintenance approach to channel restoration.
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5.4.3 Estimation of reduction in flood risk
As presented in Section 2.3 the SCS TR55 Runoff Curve Number hydrological methodology presents a means of quantifying the impact of diffuse land use and watercourse changes. Within the context of a hydrological assessment undertaken using accepted British hydrological assessment methods the results of the alternative SCS approach can be used to evaluate the scale of any changes which might be inferred for a given natural flood management measure.
The changes made to the baseline SCS TR55 hydrological model for each of the four cases are presented in Table 19, Table 20, Table 21, and Table 22.
Activity Effect Schematisation
2,850m (15Ha) of Reduced flow velocity thus - floodplain Mannings riparian planting attenuating flood flows roughness increased using appropriate passing through reach from 0.04 to 0.08 native species and - channel Mannings fenced from livestock roughness increased by 10%
328Ha of reduced Improved ground cover - reduced stocking area stocking increasing available runoff curve number interception storage and reduced to reflect thick increasing sheet flow brush roughness - reduced stocking area sheet flow Mannings roughness increased to reflect thick brush
Blocking of moorland Increasing runoff length and -Not included within drains and grips reducing areas of model (drains not concentrated flow hence represented in baseline slowing runoff rates model)
Table 19: Summary of the changes made to the hydrological model to investigate the impact of option 1 – moorland improvements to Muckle Burn headwaters
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Activity Effect Schematisation
3,500m of riparian Reduced flow velocity thus - floodplain Mannings planting using attenuating flood flows roughness increased appropriate native passing through reach from 0.04 to 0.08 species and fenced - channel Mannings from livestock roughness increased by 10%
780Ha reduced Improved ground cover - reduced stocking area stocking increasing available runoff curve number interception storage and reduced to reflect thick increasing sheet flow brush roughness - reduced stocking area sheet flow Mannings roughness increased to reflect thick brush
Table 20: Summary of the changes made to the hydrological model to investigate the impact of option 2 – moorland improvements to Danny Burn headwaters
Activity Effect Schematisation
3100m of riparian Reduced flow velocity thus - floodplain Mannings planting using attenuating flood flows roughness increased appropriate native passing through reach from 0.04 to 0.08 species and fenced - channel Mannings from livestock roughness increased by 10%
5300m of reduced Reduced flow velocity thus - channel Mannings maintenance of attenuating flood flows roughness increased by riparian margin. passing through reach 10% Localised fencing where required.
19Ha of new riparian Reduced runoff through - Not included in planting increased interception quantification storage
Table 21: Summary of the changes made to the hydrological model to investigate the impact of option 8 – improvement of the river Knaik riparian corridor
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Activity Effect Schematisation
Cease maintenance of Channel returns to more - Estimation of new 5.2km reach and natural form, resulting in channel sinuosity employ strategic longer flow path with made using NRCS roughening to subsequently reduced Stream Restoration encourage channel slope. Reduction in Design Handbook naturalisation channel size and increase in (United States channel roughness Department of Agriculture, 2007) -Channel roughness increased by 10%
Table 22: Summary of the changes made to the hydrological model to investigate the impact of option 19 – cease maintenance of straightened reach of Allan Water upstream of Greenloaning
The identified percentage change to flood flows on the River Allan at Bridge of Allan are presented in Table 23. A more detailed breakdown of the reduced flood flows and modified flood return periods at a range of locations is presented in Appendix D.
Option 2yr 10yr 50yr 100yr 200yr 500yr
Muckle Burn headwaters 98.4% 98.9% 99.2% 99.3% 99.4% 99.5%
Danny Burn headwaters 98.4% 98.5% 98.7% 98.8% 98.9% 99.0%
River Knaik riparian corridor 99.4% 99.4% 99.4% 99.4% 99.4% 99.5%
Allan Water decanalisation 99.6% 99.6% 99.5% 99.5% 99.5% 99.5%
Table 23: Identified changes in the flood flows for each of the quantitatively assessed natural flood management options
5.4.4 Estimation of baseline (existing) flood damages
In the absence of flood water levels at each property a donor flood depth curve was generated for each flood protection standard to facilitate the damage assessment as summarised in Table 24. On this basis a property which has been identified as having an onset of flooding at for example the 50yr flood event has been estimated to have a flood depth of approximately 200mm in a 100yr event and 300mm in a 200yr event.
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Onset of 25yr 50yr 100yr 200yr 500yr flooding flood flood flood flood flood depth depth depth depth depth
25yr 0mm 200mm 300mm 350mm 375mm
50yr - 0mm 200mm 300mm 350mm
100yr - - 0mm 200mm 300mm
200yr - - - 0mm 200mm
500yr - - - - 0mm
Table 24: Assumed flood depth growth curve for a range of property protection standards over a range of flood return periods
Following the estimation of flood depths at the identified flood risk properties across the catchment an assessment of flood damages was undertaken using the guidance provided within the “The Benefits of Flood and Coastal Risk Management: A Manual of Assessment Techniques” (Flood Hazard Research Centre, 2010), often referred to as the Multi Coloured Manual or MCM.
The MCM method provides the user with mechanisms to estimate the likely damages caused by flooding. The manual includes methods to assess the following types of damages:
• Damage to residential properties and the expense of clear up;
• Damage to non-residential properties and the expense of clear up;
• Intangible damage caused by flooding;
• Damage to agricultural land;
• Damage as a consequence of the closure of transport links;
• Expense incurred by emergency services;
• Damage caused by the loss of energy supply.
As reported in Section 2.3.3 flood risk within the Allan Water catchment is primarily associated with residential properties. Hence a single depth damage curve for the MCM’s generic residential property was adopted for all properties at risk of flooding within the catchment.
The base date for the assessment to which all damages are reference was 1 January 2011. To account for price inflation since the publishing of data the Retail Price Inflation Index (RPI) has been used to update to the base date.
As part of the damage assessment and inline with the MCM guidance, house rental prices within the catchment have been estimated using the average rental cost for a three bedroom house. This has been estimated using data published at www.findaproperty.com from properties in the Dunblane area. Similarly, electricity prices have been updated using the standard tariff for Scottish Hydro Electric.
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The resulting calculated average annual damages for a range of property protection standards has been provided in Table 25. The results are also shown graphically in Figure 32 along with a fitted damages function which was used to estimate the damages at each property.
Onset of flooding Annual average damages for donor residential property, adopted depth curve
25yr £911.40/yr
50yr £449.30/yr
100yr £224.00/yr
200yr £103.41/yr
500yr £53.34/yr
Table 25: Average annual damages for a range of flood protection standards developed using a donor flood depth growth function for a donor property classification (MCM standard residential)
£10,000
£1,000
AAD = 19418 x RP^(-0.9644) £100
£10 Averagedamages (£/yr) annual
£1 10 100 1000 Onset of flooding return period (yr)
Flood damages: Adopted grow th Line of best fit Adopted grow th
Figure 32: Average annual damages for a range of flood protection standards developed using a donor flood depth growth function for a donor property classification (MCM standard residential)
In developing the donor flood damage function flood damages have not been capped. Based on the data published at www.findaproperty.com the estimated value of a three bedroom house in the Dunblane area is £218,063. Adopting the developed donor damage curve it would be necessary for a property to suffer a very low standard of protection of approximately 1 in 3yr before the estimated flood damages would exceed the property value. This project has not identified any properties with a standard of protection close to the 1 in 3yr, hence the omission of capping is thought to have no impact.
Agricultural flood damages have not been assessed as part of the damage assessment as the damage functions reported in the MCM normally generate relatively insignificant flood damages to agricultural land. Table 9.10 in the
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MCM indicates flood damages of £94/ha/year (PVd = £30,827) reducing to £23/ha/year (PVd = £7,543) when the land is protected up to a 20 year event for low grade arable land. With approximately 400Ha of land at this level of flood risk within the catchment this is a relatively significant value of flood damages, potentially generating an average annual damage of approximately £9,200/yr.
The donor flood damage curve does not include any allowance for intangible damages. This decision has been made based on the relatively low value attributed to intangible damages in conjunction with the complexities of applying the assessment methodology to a catchment wide study such as this.
The estimated Annual Average Damages generated by flooding within the Allan Water catchment are presented in Table 26 and graphically in Figure 33.
Location Properties Properties Properties Properties with a with with with <50yr <100yr <200yr <1000yr SOP SOP SOP SOP AAD £/yr AAD £/yr AAD £/yr AAD £/yr
Blackford (no flood mapping) £4,580 £5,640 £5,690
Braco (no flood mapping) £15,790 £16,610 £16,780
Greenloaning £0 £2,520 £3,220 £3,340
Kinbuck (no flood mapping) £920 £920 £940
Ashfield (no flood mapping) £690 £1,280 £1,330
Dunblane (no flood mapping) £6,180 £6,770 £6,990
Bridge of Allan £42,850 £49,260 £57,000 £69,910
Total £42,850 £79,940 £91,440 £104,980
Table 26: Annual Average Damages caused by flooding within the Allan Water catchment subdivided into towns
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Estimated annual average flood damages in Allan Water catchment (baseline period) £120
£100 Thousands
£80
£60
£40
£20 Average Annual Average Flood damages (AAD)
£- 10 100 1000 Flood return period (yrs)
Figure 33: Annual Average Damages caused by flooding within the Allan Water catchment
It is noted that the previous flood damages assessment undertaken for Bridge of Allan and reported in River Forth and Allan Water Flood Study, Damage Assessment, Bridge of Allan (Halcrow, 2009) reported annual average damages of in excess of £400,000/yr for flooding in Bridge of Allan. It is accepted that this is a notable variation to the flood damages presented here. This variation is due to the following factors:
• The flood depth return curve assumed in this study is conservative (thought to be lower than actually experience).
• This study does not include intangible flood damages.
• This study has adopted a minimum onset of flooding in Bridge of Allan of the 1 in 50yr flood event, however the previous assessment in Bridge of Allan undertook a more complex analysis which incorporated the deterioration of the existing flood defence assets and the consequent flooding of properties at much more frequent return periods.
• This study has adopted a single depth-damage curve for all properties identified as flooding. Through this simplification it has been assumed that all flood risk properties experience the same flood damages as the standardised MCM residential property. It is anticipated that some of the very large industrial and commercial properties within Bridge of Allan which are thought to be at flood risk will generate significantly more flood damages than suggested by the adopted depth-damage curve.
• There are minor differences between the MCM2006 depth-damage curves which were applied to the previous damage assessment was completed using and the MCM2010 depth-damage curves which were used for this study. These minor changes have resulted in slightly smaller depth- damage curves for residential properties with a net overall impact of reducing estimated damages.
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• The damage assessment undertaken as part of this study does not take account of social deprivation factors which can be applied to account for the increased impact that flooding can have on less affluent people.
In summary it is believed that the adopted damage assessment technique is conservative, however it is not thought the factor of five observed in Bridge of Allan is repeated across the rest of the catchment. To develop a better understanding of the conservatism of the damage assessment a sensitivity analysis was conducted with the following modifications:
• Inclusion of a 1.12 DEFRA social class weighting factor to more closely represent the moderate level of wealth in the region
• A 25% deeper flood growth curve
• Where the lowest flood return period was the 1 in 100yr it was assumed that 10% of the properties which were identified as being at risk during the 100yr event had a standard of protection of 1 in 50yr.
The effect of these changes identified approximately a 20 to 25% increase in flood damages. Further discussion on this sensitivity test is presented in Appendix D.
5.4.5 Estimation of economic flood damages avoided
The estimation of economic flood damages avoided for each of the four short listed options has been calculated for each property based on the reduction in the probability of the available flood mapped events as presented in Section 5.4.2 using the same methodology as presented in Section 5.4.4 to assess flood damages. In this way it has been possible to develop an understanding of the magnitude of flood damages avoided (or economic benefits) by subtracting the present day value of the flood damages experienced from the baseline flood damages as presented in Section 5.4.4. Figure 34 summarises the methodology.
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Figure 34: A graphical representation of the calculation of the economic damages avoided used to estimate the economic benefits of the natural flood management measures
The results of the estimated average annual economic damages and benefits for each of the considered options are presented in Table 27.
Option Average Average Average annual annual annual economic damages in damages benefits baseline (after full (damages realisation) avoided)
1. Muckle Burn £104,963/yr £103,534/yr £1,429/yr headwaters
2. Danny Burn £104,963/yr £102,389/yr £2,574/yr headwaters
8. River Knaik £104,963/yr £102,854/yr £2,109/yr riparian corridor
17. Allan reduced £104,963/yr £103,991/yr £972/yr maintenance
Table 27: Summary of the calculated average annual damages and average annual economic benefits for the considered natural flood management measures
5.4.5.1 Discount factors and the conversion of average annual damages to present day values
As stated in the DEFRA Supplementary Guidance note to operating Authorities “Revisions to Economic Appraisal Procedures Arising from the New HM treasury ‘Green Book’” (and adopted by the Scottish Government) an appraisal period of 100 years should be used for a conventional infrastructure development such as flood protection schemes. It is accepted that the application of natural flood management is outside the realms of conventional infrastructure however it has been deemed that the sound principles of economic assessment as presented in the Green Book are still relevant to this type of development and therefore the procedures should still be adopted.
Discount rates have been included within the assessment to allow for the gradual reduction in significance of future benefits and costs that may occur further down the project timeline. The Green Book identifies suitable discount rates as 3.5% for the first 30 years, 3.0% for years 31 - 75, and 2.5% thereafter, these rates have been adopted in this assessment. The inclusion of discount rates enables costs and benefits that occur during the appraisal period to be translated into a present day value (PV).
As it will take anything up to a number of decades for the full benefits of the natural flood management measures considered as part of this study to be realised after the initial implementation a bedding in period has been allowed for in the calculation of discount factors. It has been assumed that the benefits presented by each option will grow linearly from the initial implementation in year zero to the full rate after a defined period. A summary of the calculation of
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discount factors and the conversion of average annual benefits into a present day value is presented in Table 28 and Figure 35.
Option Full benefit Benefits Sum of Average Present realisation in first discount annual day value period year factors economic of benefits benefits
1. Muckle Burn 25 years 20% 21.64 £1,429/yr £30,924 headwaters
2. Danny Burn 25 years 20% 21.64 £2,574/yr £55,701 headwaters
8. River Knaik riparian 25 years 0% 19.62 £2,109/yr £41,379 corridor
17. Allan reduced 25 years 0% 19.62 £972/yr £19,071 maintenance
Table 28: Summary of the calculation of discount factors and the conversion of annual average benefits into a present day value
Discount factors for a range of benefit realisation periods
1.0
0.9
0.8
0.7
0.6
0.5
0.4 Discount factor Discount
0.3
0.2
0.1
0.0 0 10 20 30 40 50 60 70 80 90 100 Year Full benefits year 0 (used for costs) Full benefits in 25 years, yr0 20% Full benefit in 25 years, yr0 0%
Figure 35: Graph showing the discount factors used for a range of benefit realisation periods
5.4.6 Estimation of capital and maintenance costs 5.4.6.1 Optimism bias
It is widely recognised that there is a tendency for appraisers of all kinds of projects to be overly optimistic in their early assessment of project costs, time scales and benefits, when these are compared with final outturn values. This is termed ‘Optimism Bias’.
To counter this HM Treasury issues guidance in the form of a percentage to increase the costs by depending on the uncertainty surrounding the estimates. An optimism bias of 60% is typically used for projects at an early stage of
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consideration with 30% normally adopted at a detailed design stage. This percentage is added to the best estimate and should be used for the purpose of budget allocation. Given the preliminary nature of the options considered as part of the option appraisal an optimism bias of 60% is deemed appropriate. 5.4.6.2 Capital costs
The construction cost for the options considered was estimated using the unit- rate method outlined in “SPONS’s Civil Engineering and Highways Price Book” (SPON Press, 2010), commonly referred to as SPONS. This method is based on the use of unit-rates for each component of each element required to construct the scheme. Where available, more specific cost data has been included in the cost assessment. This data originates from other British river engineering and flood management contracts in which Halcrow has had recent involvement, including costs used on Selkirk Flood Protection Scheme, Long Philip Burn flood management works, and the White Cart Flood Prevention Scheme.
The total construction cost or expected tender sum for each option was based on an uplifted direct cost, the direct cost representing the cost to the contractor to construct the works. The uplifting process was calculated following the guidance contained within SPONS. The following items were allowed for in this process:
• Contractor’s preliminaries: 15% of direct cost
• Contractor’s head office overheads: 6% of direct cost
• Contractor’s profit: 5% of total costs
• Maintenance of loans: 2% of total costs
Although cost figures are based on recommended unit rates and experience from previous projects they are estimated and indicative only. All estimated tender sums are relevant to 1 January 2011 prices.
It should be noted that the cost estimates make no allowance for the diversion or protection of services that could be significant when compared to other costs. Effort has been made to locate measures away from visible services however the financial risk to the project of conflict with services will remain high until utility providers have been consulted.
A summary of the capital cost estimates for the quantitatively considered options are presented in Table 29. Further details of the estimation of these costs have been provided in Appendix D.
Option Estimated Estimated Estimated direct cost tender cost tender cost (without OB) (without (with OB) OB)
1. Muckle Burn headwaters £75k £97k £142k
2. Danny Burn headwaters £97k £125k £183k
8. River Knaik riparian £73k £94k £138k corridor
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Option Estimated Estimated Estimated direct cost tender cost tender cost (without OB) (without (with OB) OB)
17. Allan reduced £14k £18k £26k maintenance
Table 29: Summary of estimated capital costs exclusive of land access costs, provision for services and other contingencies 5.4.6.3 Maintenance costs
The flood mitigation measures proposed within this report require sustained maintenance in order to have a chance at achieving the assessed benefits. Should maintenance not be undertaken it is unlikely that the value of benefits calculated will not be realised resulting in an impact on the benefit-cost ratio of the adopted measures. Maintenance items included within the economic assessment of the scheme include:
• Routine maintenance; and
• Routine post implementation monitoring.
It is assumed that routine maintenance and monitoring would be undertaken by local authority personnel, SEPA staff or the existing land manager on a part-time basis and that the staff would available to undertake other worthwhile work when not maintaining the measures. The routine monitoring makes allowance for post implementation monitoring inline with industry best practice but does not extend to cover scientific monitoring which may be undertaken to assess the effectiveness of the implemented pilot option.
The following assumptions have been applied to develop the maintenance and post implementation costs:
• All fencing will be maintained at a cost equivalent to a complete replacement every 30 years
• All stiles and gates will be maintained at a cost equivalent to a complete replacement every 20 years
• All tree planting will be maintained at a cost of £250/Ha/year for the first five years to facilitate establishment. No allowance for maintenance after this initial establishment period has been included.
• An allowance for an annual walkover survey by a “competent person” of the Allan Water for the cessation of maintenance option has been included for the first 25 years after implementation. Provision has been made for the walkover surveys to be supplemented with a more detailed 5 year inspection by a specialist geomorphologist.
No allowance has been made for emergency maintenance which is assumed will remain comparable with the baseline existing conditions within the study area.
Maintenance and monitoring costs for the options are outlined in Table 30. A more detailed breakdown of the cost estimates for the options has been included in Appendix D.
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Option Estimated Estimated maintenance and maintenance and monitoring cost monitoring cost (without OB) (with OB) (Present day value) (Present day value)
1. Muckle Burn £45k £72k headwaters
2. Danny Burn £56k £90k headwaters
8. River Knaik riparian £46k £74k corridor
17. Allan reduced £71k £114k maintenance
Table 30: Summary of estimated maintenance and post implementation monitoring costs for each of the options considered
The assessment does not quantify the value of maintenance avoided although it should be accepted that options such as the cessation of maintenance along the straightened reach of the Allan Water and the reduced management of large woody debris on the River Knaik are likely to present notable savings in maintenance costs. A preliminary estimate of the present day value of maintaining the straightened reach of the Allan Water is in the region of £29k based on two weeks of a 21T excavator at 10 year maintenance intervals.
5.4.7 Estimation of other benefits and disbenefits
The non-economic benefits and disbenefits of the options have been assessed in compliance with the methodology presented in Supporting Guidance (WAT-SG- 67) Assessing the Significance of Impacts – Social, Economic and Environmental (SEPA, 2009).
The qualitative option appraisal process identified that the four options progressed from the short listing process offer environmental benefits and at worst have been assessed to be environmentally neutral. For this reason Supporting Guidance (WAT-RM-34) Derogation Determination – Adverse Impacts on the Water Environment (SEPA, 2009) has not been applied.
A majority of the identified impacts of the considered natural flood management options will have a duration of longer than six years, hence the scale of impacts will not be reduced due to a short lived duration as presented in Table 31.
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Table 31: Indicative guide to ranking the magnitude of an identified impact, extracted from WAT-SG-67 (SEPA, 2009)
Using the methodology within WAT-SG-67 the significance of an impact, both positive and negative, can be assessed using the methodology outlined in Table 32. This methodology combines the magnitude of an impact with the importance of a factored impact to determine an overall significance.
Table 32: Indicative guide to assessing the significance of an impact, extracted from WAT- SG-67 (SEPA, 2009)
The main social and environmental factors for each of the options to be progressed from the short list have been assessed following the principles of WAT-SG-67. The outcomes of these assessments are presented in Table 33, Table 34, Table 35 and Table 36. The assessed significance of each of these factors are then compared alongside the economic benefits in Section 5.4.8.
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Factor Description Assessed Assessed Assessed scale importance significance
Flora and fauna The modified stocking would Small Low Very low (+ve) provide additional variation of available habitats
Water The riparian planting would Negligible Negligible Negligible (+ve) improve the quality of habitats along the Muckle Burn however the poor status is due to a barrier to fish passage which would remain
Landscape The naturalisation of the Small Medium Low (+ve) hillside would be an improvement to landscape and visible from the A9
Way of life Reduced stock and land take Small Medium- Low (-ve) for riparian planting would high (WAT- impact on farm incomes SG-67 suggests negligible)
Community New fences could form a Small Low Very low (-ve) barrier to access for hill walkers and other users. Propose to mitigate using gates & stiles
Table 33: Summary of the main non-economic benefits and disbenefits for option 1, improvement of the Muckle Burn headwaters
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Factor Description Assessed Assessed Assessed scale importance significance
Flora and fauna The modified stocking would Small Low Very low (+ve) provide additional variation of available habitats
Water The riparian planting would Negligible Negligible Negligible (+ve) improve the quality of habitats along the Danny Burn however the poor status is due to a barrier to fish passage which would remain
Landscape New fence may be an Small Very low Negligible (-ve) unsightly intervention on the landscape particularly if it is along the catchment boundary. (Regeneration of woodland will only be visible from within the localised area)
Way of life Would reduce the area of land Small Medium- Low (-ve) available for farming, hence high (WAT- reducing local income. (Note SG-67 existing un-intensive landuse suggests within Highland Springs negligible) area)
Community New fences could form a Small Low Very low (-ve) barrier to access for hill walkers and other users. Propose to mitigate using gates & stiles
Table 34: Summary of the main non-economic benefits and disbenefits for option 2, improvement of the Danny Burn headwaters
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Factor Description Assessed Assessed Assessed scale importance significance
Flora and fauna The riparian planting would Small Low Very low (+ve) provide additional habitat variation both aquatic and land
Water The riparian planting would Negligible Negligible Negligible (+ve) improve the quality of habitats along the River Knaik however the poor status is due to a barrier to fish passage which would remain
Landscape The increased naturalisation Small Medium Low (+ve) would an improvement to the local landscape but would only be visible from a relatively minor local road
Way of life Would reduce the area of land Small Medium- Low (-ve) available for farming, hence high (WAT- reducing local income. (Note SG-67 existing un-intensive landuse suggests within Highland Springs negligible) area)
Community No impact No impact
Table 35: Summary of the main non-economic benefits and disbenefits for option 8, improvement of the River Knaik riparian corridor
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Factor Description Assessed Assessed Assessed scale importance significance
Flora and fauna Could improve variation and Small Medium Low (+ve) extent of good aquatic habitats. Could improve quality of floodplain habitats (and neighbouring protected sites) by improving linkage with watercourse
Water The 5.3km reach is currently Medium(- Medium Medium (+ve) classified as bad due to being large) canalised. Potentially it could become moderate but more likely to be poor due to fish barriers which may remain
Landscape The restored reach would be a Medium Medium Medium (+ve) significant improvement over the existing case and would be highly visible from the railway line and partly visible from trunk road
Way of life Could result in improved Medium Low Low (+ve) sport fishing in the area by improving fish stocks.
Community Could offer improved Very small Very low Negligible recreational facility for walkers (without improved path network impact is limited)
Table 36: Summary of the main non-economic benefits and disbenefits for option 19, cease maintenance of the straightened reach of the Allan Water
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5.4.8 Additional opportunities
With the implementation of the natural flood management measures there is an opportunity to include parallel projects or minor works to bring additional benefits which are not core to the principles of natural flood management. Through economies of scale and other synergies these additional activities may assist in bringing additional benefits at a relatively small increase in cost. However it should be noted that in order to realise these additional benefits it would be necessary to access additional funding streams beyond those which might be applicable to natural flood management measures. A summary of some identified additional opportunity projects which could be implemented in parallel to the considered natural flood management measures are presented in Table 37.
Option Social opportunities Environmental opportunities
1. Muckle Burn - (remote, therefore limited - Improvement of fish passage at headwaters opportunities) downstream weir through the provision of a fish pass or removal of the weir
2. Danny Burn - Extension/improvement of - Improvement of fish passage at headwaters local path network to downstream weir and culvert improve amenity value for through the provision of a fish pass local residents and increase or removal of weir. number of visitors to region
8. River Knaik - Extension/improvement of - Improvement of fish passage at riparian local path network to downstream weir and culvert corridor improve amenity value for through the provision of a fish pass local residents and increase or removal of weir. number of visitors to region - Provision of roosting/nesting boxes within areas of existing mature trees to improve wildlife provision
17. Allan - Creation of a footpath along - Improvement of fish and reduced reach to improve amenity mammal passage at A9 culverts maintenance value for local residents and increase number of visitors to region. Path could interlink with existing Carsebreck network and provide walking route between Braco, Greenloaning and Blackford.
Table 37: The potential opportunities for the accrual of additional benefits associated with each of the considered options
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5.4.9 Comparison of benefits and costs
As presented within the previous sections of this chapter the benefits and costs of each of the natural flood management measures have been assessed for the four options progressed from the short listing stage. The environmental, social and economic credentials of each of the options have been assessed following standard procedures.
• Social and environmental, benefits and disbenefits, assessed using WAT- SG-67 (SEPA, 2009);
• Economic benefits (flood damages avoided) assessed using simplified MCM procedure; and
• Economic costs, capital and maintenance, assessed using published unit price data.
The results of the quantification of the identified factors are presented in Table 38 and Table 39. As might be anticipated on the basis of pure economics none of the considered natural flood management options present a compelling case for progression with benefit-cost ratios of significantly less than unity. However on consideration of all factors, the viability of the considered projects is understandably much stronger. Following the procedures laid out in WAT-SG- 67 (SEPA, 2009) the option of ceasing maintenance along the straightened reach becomes very attractive as the options accrues two positive impacts of medium significance.
Option Estimated Estimated Estimated Estimated Indicative capital maintenance economic economic economic costs costs costs benefits benefit – including including OB, including including cost ratio OB, PV PV OB, PV OB, PV
1. Muckle £142k £72k £214k £31k 0.14 Burn headwaters
2. Danny Burn £183k £90k £273k £56k 0.21 headwaters
8. River Knaik £148k £74k £222k £41k 0.18 riparian corridor
17. Allan £26k £114k £140k £19k 0.14 reduced maintenance
Table 38: Summary of the economic assessment of the considered options
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Option Environmental and Environmental Economic Overall social benefits & and social ranking ranking disbenefits summary benefits ranking
1. Muckle Burn Very low (+ve) 3 4 4 headwaters Negligible (+ve) Low (+ve) Low (-ve) Very low (-ve)
2. Danny Burn Very low (+ve) 4 1 3 headwaters Negligible (+ve) Negligible (-ve) Low (-ve) Very low (-ve)
8. River Knaik Very low (+ve) 2 2 2 riparian corridor Negligible (+ve) Low (+ve) Low (-ve)
17. Allan reduced Low (+ve) 1 3 1 maintenance Medium (+ve) Medium (+ve) Low (+ve)
Table 39: Summary of the social, environmental and economic benefits and disbenefits of the considered options. Ranking, 1 is highest and 4 is lowest.
Given that all the considered options offer a relatively weak pure economic case the option of reducing maintenance on the straightened reach of the Allan Water has been identified as the strongest option for progression as the pilot project on the grounds of its good environmental and social credentials. As further considerations the reduced maintenance option of the Allan Water option offers;
• A significant reduction of maintenance costs;
• Is situated in currently non-productive land; and
• Offers a good opportunity to provide significant amenity value should an improved path network be put in place.
Conversely, it should be noted that the implementation of the Controlled Activities (Scotland) Regulations is likely to significantly reduce the quantity of maintenance that will be undertaken along this reach without it being progressed as a formal natural flood management project.
It may also be more desirable to consider a pilot site that on a sub-catchment scale which have been identified during previous restoration projects as more effective than reach scale interventions. If a sub-catchment based approach is preferred then the Danny Burn catchment headwaters option might be considered as it offers the strongest hydrological benefits and good restoration
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potential provided some minor additional works are undertaken to improve fish access. As further considerations the option;
• Is aligned with the interests of current land use;
• A sub-catchment scale project; and
• Offers a good opportunity to provide significant amenity value should an improved path network be put in place.
5.5 Final selection of pilot projects
At the third steering group meeting (16 May 2011) it was decided by the steering group to not progress the sub-catchment scale restoration options as the demonstration project for the following reasons:
Option 1 – Muckle Burn headwaters
• The site would be difficult to access therefore reducing the opportunities to inspire other projects in the catchment
Option 2 – Danny Burn headwaters
• The mix of current land stakeholders in the sub-catchment would present a significant risk to the project. The non-cooperation of any of the water users, landowners or tenants could potentially prevent the pilot from progressing.
Initially it was proposed that two pilot projects might be progressed into the next phase of the project, assisted naturalisation of the Allan Water and restoration of the riparian corridor on the River Knaik. However initial scoping into the assisted naturalisation of the Allan Water presented a number of issues that are presented in Section 7.7.
Hence the restoration of the riparian corridor along the River Knaik has been selected as the preferred pilot site. This selection is based on the following:
• Local perception is that the River Knaik is the dominating contributor to flood risk within the Allan Water catchment. This perception has been supported by the hydrological analysis undertaken as part of this study;
• Early consultation with the main landowners has identified that the landowners are amenable to improvements to the riparian corridor;
• The riparian planting would be consistent with Local Biodiveristy Action Plans and the Forestry Commissions Potential Native Woodland Network. These consistencies would improve the prospect of securing funding;
• It is a sub-catchment scale project;
• The River Knaik and its riparian corridor is visible from the B827 therefore offering increased public exposure;
• The River Knaik contains good riparian reaches alongside poor reaches that will be valuable for demonstrating what is being proposed to land managers and other stakeholders. It will also demonstrate that what is being proposed is feasible;
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• There are a number of similar sub-catchments within the wider Allan Water that could benefit from similar riparian improvement projects such as the Danny Burn, Ogilvie Burn, Muckle Burn, Keir Burn, Millstone Burn and Wharry Burn. The restoration of the River Knaik would be a good demonstration site to these land managers; and
• The presence of cultural heritage sites in the lower catchment and the scenic Braco Falls all within walking distance of Braco offers the opportunity for significant amenity improvements through the extension of the existing path network.
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6 Monitoring strategy
6.1 Introduction
6.1.1 Purpose of document
This document provides a detailed and justified monitoring strategy that should be applied along side the implementation of a River Restoration / Natural Flood Management project on the Allan Water. The strategy will allow the effective evaluation and appraisal of works undertaken. The approach used to develop the strategy follows best practice and each step has been presented so that recommendations can be easily adapted in the case of alternative projects being implemented on the Alan Water. The plan includes both pre-project and post- project phases.
Some flexibility is possible in the implementation of the strategy, allowing for budgetary and time constraints. However, monitoring such projects is a fundamental element of ‘best practice’ and Water Framework Directive guidelines. Cutting back on the proposed strategy is strongly cautioned against and, where attempted, should be clearly justified.
6.1.2 Rational of monitoring
Monitoring is, and should be, an important component of restoration projects (Bruce-Burges and Skinner, 2002). However, although their importance has been recognised for some time (Boon, 1998), monitoring schemes have typically been ad hoc and are generally dictated by time and money, and are poorly targeted (England et al., 2008). For this reason, the development process has been formalised into key stages for this project. The results of each step are presented in the following sections.
6.1.3 Approach to study design
The approach used to develop a monitoring strategy for the Allan Water has been based on expertise from a number of sources. These include RRC workshops specifically targeted at the river restoration monitoring, textbooks, journal articles and conference proceedings, as well as expertise held within the Centre for River Ecosystem Science and Halcrow. Published recommendations generally focus on the importance of tying monitoring to project objectives and developing specific hypotheses with consideration of the scale and complexity of the project (e.g. Roni, 2010).
The decision process behind the selection of methodologies has been clearly documented allowing the monitoring strategy to be as flexible as possible for further development. However, the importance of comprehensive monitoring should not be underestimated. Failure to monitor a project carefully may lead to added expense or missed opportunities in the project’s future.
Perhaps most importantly, the approach allows for adaptive assessment. “Modification of monitoring and analysis methods as a dynamic system evolves following restoration activities” (Florsheim et al., In press).
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6.1.4 Important considerations 6.1.4.1 Spatial and temporal scale
Rivers are hierarchical systems; important ecosystem processes that occur at small scales cumulatively shape larger reach and catchment scale processes. Likewise catchment characteristics link the landscape scale to the functioning of individual organisms. Connections to the landscape occur in three dimensions and have an influence through time (Roni, 2010). Geomorphological and ecological attributes therefore operate at multiple spatial and temporal scales. Although scales are continuous, monitoring strategies are generally focused at three levels; habitat, reach and catchment. Temporal scales are more variable but, in general, monitoring should be more intense at early stages of the project, with longer term monitoring continuing at a lower level for 15 to 20 years after the completion of restoration work. 6.1.4.2 Risk
Larger scales are likely to include a greater range of habitats and more complex ecosystem processes relative to small site-level projects. Implementation of novel techniques implicitly has higher levels of uncertainty. Restoration in sensitive locations requires a greater level of certainty in the results of monitoring. These all introduce risk to the project that has to be managed with the support of data collected as part of the monitoring. 6.1.4.3 Habitats
Much of the monitoring will be focuses on the habitats present or restored. These will partly determine the choice of monitoring methods available. 6.1.4.4 Control sites and baseline data
Where monitoring is undertaken without sound scientific reasoning, projects risk producing meaningless or misleading data (England et al., 2008). The use of Before-After-Control-Impact (BACI) designs allow changes attributable to the restoration project, to be distinguished from those associated with natural environmental trends and variability (Roni, 2010). These rigorous approaches also provide the opportunity for ‘investigative elements’ to the post- implementation surveys (England et al., 2008).
Baseline data greatly enhances the ability to interpret biological and physical responses to environment projects (Roni, 2010). Where possible replication adds to the investigative power and clear, testable hypotheses will aid both project appraisal and the dissemination of the knowledge gathered. 6.1.4.5 Effectiveness of indicator groups
Understanding the sensitivity and response times of indicators is an important step in the selection process, often missed during the development of monitoring strategies. The effectiveness of indicators can be affected by both the temporal and spatial scale of the project as well as the type of restoration work undertake.
A summary of results from a survey of river restoration practitioners undertaken by Matthews et al. (2010) provides the following insights. Indicator groups that have been demonstrated to provide evidence of progress towards restoration goals within the initial 5 years of monitoring include mainly non-ecological
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indicators, with one exception. Groups included the following indicator types; hydrological, terrestrial flora and fauna, morphological, habitat structure and indicators of ecosystem function. Ecological indicators including fish, macrophytes and macroinvertebrates perform relatively poorly within the 5 year timeframe. However, their effectiveness, as a monitoring tool, improved in larger rivers, urban rehabilitation projects and projects that restored lateral connectivity.
6.2 Development of monitoring objectives
6.2.1 Development
These have been developed from best practice and are based on ‘SMART’ and ‘WAFA’ guidelines, produced through workshop discussions (RRC, 2007) for identifying appropriate objectives for monitoring strategies. They require that consideration is given to whether the objectives are sufficiently Specific, Measurable, Achievable, Realistic and Time-bound. Furthermore, how worthwhile undertaking monitoring is and the future applications for the data should also be questioned.
6.2.2 Areas to be covered
Monitoring will need to fulfil a number of purposes. Information may be needed to support five key areas:
• Managing risk
• Guiding the implementation of adaptive management strategies
• Evaluating the ecosystem health that develops
• Appraisal of project objectives
• Increasing the scientific knowledge base
Monitoring options are discussed with reference to these five elements. A range of recommended monitoring methodologies and tools have been scored according to their relevance in each category for both riparian restoration on the Knaik and floodplain restoration on the Allan Water. Recommendations for monitoring objectives are presented below. The implication of any changes to these objectives for the proposed monitoring strategy should be considered before implementation. 6.2.2.1 Managing risk
Monitoring should aim to provide information allowing risk to be quantified in the following areas.
• Infrastructure damage
• Ecosystem damage during and post restoration works
• Development towards an undesirable endpoint
• Failure to meet project objectives
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6.2.2.2 Guiding the implementation of adaptive management strategies
Monitoring should aim to provide sufficiently detailed information to guide adaptive management. Adaptive management requires the continual, systematic collection of data, allowing management to improve and adapt over time. This approach acknowledges the uncertainty inherent when working with natural systems and is now well established in the environmental sciences (Florsheim et al., In press) 6.2.2.3 Evaluating the ecosystem health that develops
Although not the only focus, ecological objectives of a restoration or NFM project will be a significant part of the monitoring strategy. The details will depend on specific project being advanced.
Riparian restoration on the river Knaik
• Hydrology – Reduce discharge by increasing path length, flow complexity and instream roughness. Increase the riparian roughness, slowing bankfull and out of bank flows.
• Ecology – improve ecological condition of the stream by increasing habitat diversity, providing cover and refugia, and restoring natural processes including the input of coarse organic matter and woody debris into the channel.
• Geomorphology – retain fine sediments.
Remeandering/naturalisation of the Allan Water
• Hydrology – Natural hydraulic regime, increased frequency of out of bank flow, increased flood storage, increased flow path length.
• Ecology – Increased biodiversity and amenity value, increased habitat area and niche diversity, development of floodplain habitats, reduced management requirements for invasive species.
• Hydromorphology – Improved ecological status, geomorphological improvements, reduced channel maintenance requirements. 6.2.2.4 Appraisal of project objectives
A requirement of the monitoring will be to assess whether objectives of the restoration or natural flood management project have been met. In addition to ecological objectives, Natural flood management and restoration both have socio economic objectives. These include:
• Public access and amenity value
• Dissemination of information
• Increased opportunities for education
• Answering scientific hypotheses
• Increased management experience
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This section of the monitoring strategy may not be fully addressed for many years after completion of restoration works. For example, the natural flood management and ecological benefits of riparian restoration on the River Knaik are contingent on the maturing of the riparian vegetation including trees. This may be a slow process and objectives are likely to be realised in the long term. Changes are unlikely to be seen in within the period traditionally recommended for monitoring restoration projects. Very long-term monitoring will be required to detect changes to stream and catchment hydrology.
6.3 Identifying monitoring priorities
6.3.1 Prioritising disciplines
An expansive range of biotic and abiotic disciplines have the potential to provide data suitable for monitoring restoration and NFM projects. The following tables have been drawn up to provide an indication of which areas may be most informative with regard to the different purposes outlined above (Section 6.2.2). These have been completed for riparian restoration on the River Knaik (Table 39 Error! Reference source not found. ) and floodplain restoration options on the Allan Water (Table 41) from the shortlist. They differ depending on the project being implemented, but would be easily modified for further projects within the catchment.
The strategy was then further developed for monitoring riparian restoration on the River Knaik by choosing methodologies within the prioritised areas that are appropriate to the scale and risk associated with the project.
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Table 40: Scientific disciplines that should be considered in the development of a monitoring strategy for riparian restoration on the River Knaik. The importance of each discipline within each of the areas covered by the monitoring has been considered at each hierarchical level. The table provides a clear indication of methods that should be prioritised and has been used to guide the development of the monitoring strategy monitoring strategy
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Table 41: Scientific disciplines that should be considered in the development of a monitoring strategy for a remeandering project if it were taken forward on the Allan Water. The importance of each discipline within each of the areas covered by the monitoring has been considered at each hierarchical level. The table provides a clear indication of methods that should be prioritised for monitoring and has been used to guide the development of the monitoring strategy monitoring strategy.
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6.4 Level of monitoring detail
In addition to the five purposes variously addressed by the different biotic and abiotic elements, in relation to the project goals, the levels of project scale and risk affect the level (or intensity) at which monitoring should be considered. A range of habitat elements can potentially be monitored at different detail, following restoration works. The level of monitoring detail desirable is higher for larger scale projects and for projects with less predictable outcomes.
• Larger scales are likely to include a greater range of habitats and more complex ecosystem processes relative to small site-level projects.
• Implementation of novel techniques or restoration in sensitive locations requires a greater level of certainty in the results of monitoring.
Matrices have been developed for a range of disciplines, providing expert guidance on the intensity of monitoring that is considered appropriate. This has been summarised in Figure 36 and interpreted with regard to the range of shortlisted options agreed earlier in the project.
Figure 36: Diagram summarising the information on recommended levels of sampling across different scientific disciplines from four separate matrices produced during a workshop. Recommendations for monitoring were made by a Monitoring Working Group of river restoration experts (RRC, 2007) for different scales of project size and risk and represent ‘best practice’ in river restoration. Starting with small low risk projects, each consecutive cell lists the additional detail of monitoring required to comprehensively appraise river restoration projects. Credit: The Centre for River Ecosystem Science.
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In order to match the projects to expert guidance, the shortlisted options have been presented below (Figure 37) on the same axes, developed for indicating the intensity of monitoring that is considered appropriate (RRC, 2007).
Figure 37: Matrix showing the position of the shortly sted options with regard to project size. This can be used to determine the recommended level of detail that should be undertaken when monitoring projects.
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6.5 Existing monitoring
6.5.1 Hydrology – SEPA Hydrometric network
The Allan Water catchment is gauged at two locations, both velocity-area stations.
• Bridge of Allan from 1971 (NGR NS 78591 97984, catchment area 210km 2).
• Kinbuck from 1957 (NGR NN 79225 05376, catchment area 161km 2).
6.5.2 Water quality – SEPA Biological and Chemical Monitoring
Routine monitoring is undertaken by SEPA at a number of locations throughout the Allan Water catchment. These sites will form an important part of a data gathering network that will help appraise the catchment level effects of restoration on the Allan Water and its tributaries. Monitoring extends to a number of disciplines. 6.5.2.1 Chemistry
Water physiochemistry: Temperature, conductivity, suspended solids, dissolved oxgygen % saturation, Biochemical Oxygen Demand, pH, Alkalinity, Ammoniacal-N,NH4, Non-ionised Ammonia NH3, Total Organic Nitrogen, Nitrite, Nitrate, Ortho-P, Chloride, Total P and Silicate. 6.5.2.2 Macroinvertebrates
SEPA macroinvertebrate sites currently extend to 17sites across the Allan Water catchment. Most have been surveyed twice annually since 2005. The site locations are presented in the table below.
Location River National Grid Reference
U/S of Allan Confluence Scouring Burn
Milton of Panholes Allan Water
D/S Ashfield Allan Water
Kippenross House Allan Water
U/S of Allan Confluence Millstone Burn
B8033 Road Bridge Muckle burn
Greenloaning River Knaik
Greenloaning u/s of Allan Water Knaik Confluence
Blackford Allan Water NN 89937 09178
Drumdruills Wharry Burn
Millhill Road Bridge Rhynd Burn
Rhynd Farm Rhynd Burn
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Location River National Grid Reference
Bridge of Allan Allan Water NS 78911 97368
Kinbuck Allan Water NN 79070 05011
U/S of Allan Confluence Danny Burn NN 89554 09273
U/S Highland Spring Allan Water
U/S of Blackford STW Allan Water
Table 42: Table showing the locations of macroinvertebrate surveying in the Allan Water catchment 6.5.2.3 Macrophytes
SEPA Macrophyte survey sites are currently limited to one location surveyed in September 2007. Site information is presented in the table below.
Location River Site code
u/s A9 road bridge, Bridge of Allan Water 350395 Allan
Fishers Green Allan Water 350394
U/S Wharry Burn Allan Water 350398
u/s railway line, Cornton Allan Water 350396
Table 43: Table showing the locations of the macrophyte survey surveys in the Allan Water catchment 6.5.2.4 Diatoms
Detailed data from diatom analysis has been collected from one site since 2007. An additional site was surveyed in 2007 and 2008. Site information is presented in the table below.
Location River Site code National Grid Reference
Bridge of Allan Allan Water 3609 NS 78911 97368
U/S of Blackford STW Allan Water 337301 NN 89554 09273
Table 44: Summary of the diatom survey data for the Allan Water
6.5.3 Fish – Forth Fisheries Trust salmonid surveys
A limited numbed of fish surveys has been carried out in the past by the Forth Fisheries Trust and the Allan Water Angling Association.
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6.5.4 Morphology
Habitat Quality Assessment and Habitat Modification Scores have been generated from River Habitat Surveys carried out by SEPA at the following locations. Site information is presented in the table below.
Location River Survey National Grid code Reference
U/S Highland Spring Allan Water 13823 NN 91600 09200
Blackford Allan Water 13824 NN 89600 09400
Deaf knowle Allan Water 13825 NN 87900 09400
D/S Brick house Allan Water 13826 NN 85900 08800
U/S Knaik Confluence Allan Water 13827 NN 84100 07900
Gallowston Plantation Allan Water 13828 NN 82300 07600
D/S Muckle Confluence Allan Water 13829 NN 81700 06600
Cut off meander Loop Allan Water 13830 NN 80700 06300
Mid Cambushinnie Allan Water 13831 NN 79800 05900
D/S Ashfield Allan Water 31646 NN 78354 03177
Mill of Ardoch River Knaik 13823 NN 83300 11100
Table 45: Summary of the morphology survey information for the Allan Water
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6.6 Future monitoring
6.6.1 Structure
The monitoring network proposed for the Allan Water Catchment follows a nested design reflecting the hierarchical nature of river ecosystems. The means that a network of monitoring sites across the catchment will be complemented by more detailed reach and site level monitoring ‘nested’ within the broader network. This is discussed below at four levels; catchment, tributary (sub- catchment), reach, and site. In some cases changes to existing monitoring practices, such as the frequency or rigor of sampling, may be required. 6.6.1.1 Catchment level
The range of data collected by SEPA across a number of monitoring sites will provide the basis for the higher level of the monitoring network.
Relatively good coverage is currently provided for benthic macroinvertebrates and habitat quality/modification (RHS). However, there is a need to extend the network to areas that have been identified as potential restoration options but where there is currently a lack of monitoring sites. This will require additional sites on the River Knaik, the Muckle Burn and the Danny Burn. Consideration should be given to which of the other shortlisted options might be taken forward in the future and sites added accordingly.
Less coverage is provided in other areas include macrophytes and diatoms. These are not so important for appraisal of those projects currently proposed. However, effort should be made to increase the regularity of collection. Providing an element of baseline data for future projects within the Allan Water catchment.
Water chemistry sites will also be important for projects expected to help reduce nutrient and sediment runoff such as with riparian restoration. Data collected is extensive but additional sites may be required downstream of restored sections and at know point sources.
Extensive hydrological datasets are maintained by SEPA for two locations on the Allan Water providing an excellent baseline against which changes can be compared. However, comparisons will have to be made with reference to the climatic variation. The network should be extended to include rainfall data with gauges being located in each of the major Allan Water sub-catchments. This could include installation of an automatic gauge at Knoxfauld Farm, where a rainfall data set is thought to cover the last 20+ years. 6.6.1.2 Tributary catchment level
There will be a need for research driven ‘demonstration catchments’ if the Allan Water is to serve as a demonstration of restoration/NFM at the catchment scale. Future NFM projects on the hill slopes of the Knaik, Muckle and Danny Burn all have potential in this regard. Gauging the most likely catchments to build up a baseline data set would be recommended.
Where projects aim to increase precipitation inception or infiltration rates, monitoring can be undertaken in the form of long term research projects. A
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network of dip wells, rain gauges and stage recorders would need to be designed to suit the specific project. 6.6.1.3 Reach level
Gauging stations upstream and downstream of restored reaches provide the opportunity to investigate the hydrological effects of different techniques e.g. remeandering and floodplain restoration.
There is the potential for this type of monitoring on the River Knaik, However, changes are likely to be difficult to detect, especially in the short term and on the scale proposed. Reach scale monitoring in this instant may be better focused on hydromorphology and biodiversity elements.
Fluvial audits and habitat surveys at the reach scale have the potential to detect changes in sediment processes and stream morphology, and the development and dynamic nature of instream habitats. This detail of monitoring is not routinely undertaken by SEPA but will be important for both guiding adaptive management choices (including identify changes in risk) and for appraising project objectives Surveys typically include assessment of instream LWD which in the long term may provide the Natural Flood Management benefits by increasing path length and channel bed roughness.
Fixed-point photography is an effective method of rapidly documenting riparian habitats and hydromorphic changes providing a survey method for years where reduced detail surveys are proposed.
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6.6.1.4 Site level
Site level monitoring should be rapid and easy to undertake making it available to a range of possible groups. Locations should be targeted at areas of expected change to document rates and patterns of change and clearly tie in to the project objectives.
Hierarchical Survey Value Recommended level co-ordination or purpose approach
Catchment Broad network of sites across Important for detecting catchment Follow established SEPA the Allan Water catchment level changes Hydrology/Ecology survey protocols for co-ordinated and monitored and for assessing NFM project comparison with existing by SEPA staff. objectives to at risk properties. baseline data sets allowing robust project appraisal.
Tributary Demonstration sub- Provide an opportunity evaluating Follow scientific protocols catchment catchments within the wider the effectiveness of techniques for including BACI design. Allan Water catchment evaluation and demonstration Collection of baseline coordinated by SEPA, Allan purposes. datasets where possible. Water NFM group or other Sites co-ordinated with research body. Potential PhD SEPA locations where research. appropriate.
Reach More detailed survey Provides information on specific Use of SEPA and Fisheries element to be incorporated restoration and NFM actions for survey techniques/protocols into SEPA routine evaluating risk, adaptive with replication. Data monitoring, Fisheries Board management and assessment of collected at a greater spatial or contracted out to biodiversity objectives. and temporal resolution consultant compared to catchment level sites
Site Mini research projects carried May provide additional scientific Rapid assessment out by university students, insights whilst enthusing community techniques local fisheries trusts or citizen participation. science.
Table 46: Summary table showing the relative detail of different levels in the proposed monitoring and research network
6.6.2 Recommended methods for monitoring a riparian restoration (River Knaik)
The influence of restoration works on macroinvertebrate populations is likely to be relatively localised on the River Knaik which has relatively extensive riparian margins on downstream sections. Additional sites will be required.
Catchment level
• Additional sampling sites to augment the broad network of existing sites. One should be located immediately downstream of the section of restored riparian zone.
• Gauging station on the Knaik.
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Reach level
• Fixed point photography of hydromorphology and riparian habitats. 50m intervals at fixed locations and in fixed upstream, downstream cross channel and in channel directions.
• River Habitat Survey during reduced detail years.
• Ecological surveys (Lamprey, Salmonids), RCS, GeoRHS Fluvial audits during high detail years.
• Vegetation surveys incorporating transects at several per kilometre.
• Macroinvertebrate surveys during high detail years.
• Co-ordination of survey timing to increase integration (see proposed monitoring schedules).
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6.6.3 Schedules for monitoring
Table 47: Table showing recommended frequency of monitoring work for the different disciplines if a project is taken forward to restore the riparian zone along the River Knaik. The schedule has been designed to provide the right level of detail for each of the areas that the monitoring information will support.
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Table 48: Table showing recommended frequency of monitoring work for the different disciplines, if a remeandering project was taken forward on the Allan Water. The schedule has been designed to provide the right level of detail for each of the areas that the monitoring information will support.
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6.6.4 Feedback from monitoring
Monitoring should be a reiterative process i.e. results should be used to reassess and reshape both project management and the on-going monitoring program. This allows objectives to be constantly reviewed in the light of ecosystem development, important for successful adaptive management. Figure 38 presents a flow chart showing the steps that should be followed.
Figure 38: Flow diagram showing how feedback from monitoring should be applied to the management considerations for the restoration project. The process represents best practice and is recommended by experts in the field of river restoration. Credit: The Centre for River Ecosystem Science.
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6.7 Further considerations
6.7.1 Integrated monitoring
The monitoring strategy involves integration of the many elements. Suggestions to use existing monitoring locations have been made where any reduced integration, which result in an anticipated acceptable standard of output, is considered acceptable. Surveys should be co-ordinated in terms of location, timing and scale.
6.7.2 Other indicators
An emphasis is generally placed on ecological, hydrological and morphological indicators in monitoring schemes, whilst the socio-economic has frequently been neglected (Matthews, 2010). Careful consideration should be given to the socio- economic objectives of the project and how best to monitor them. They are likely to include Amenity value, countryside access, tourism and fishing. Numerous methods exist that can be implemented towards the end of the project. An additional aspect of the Allan Water project will be its demonstration value and the successful communication of results. As a clear project objective, some level of assessment, possibly via a project review by line management, should be implemented.
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7 Design and specification for pilot project
7.1 Introduction
In conjunction with the Steering Group it has been identified that the preferred pilot demonstration site for the Allan Water Natural Flood Management Programme is the restoration of the River Knaik’s riparian corridor. This can be divided into two main elements:
i) Extensive riparian planting in the upper catchment in the vicinity of the confluence of the Corriebeagh Burn and Arrevore Burn with the River Knaik.
ii) Improvements in riparian fencing with scattered infill riparian planting opportunities.
To facilitate the rapid progression of this project additional design work has been undertaken. This additional design work is such that focused and meaningful consultation can take place with landowners, funding bodies, regulators and other stakeholders.
The following activities have been undertaken:
• Identification of riparian planting opportunities by;
- Flood mapping of the upper River Knaik
- Site based catchment reconnaissance
• Preparation of a range of tree planting specifications (using species of local provenance);
• Identification of riparian planting opportunities by site based reconnaissance;
• Preparation of fencing specifications to protect the proposed tree planting and allow existing vegetation to increase its extent; and
• Identification of physical constraints to implementation including the location of utilities within the catchment.
These activities are presented in the following sections.
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7.2 Generation of flood maps for the River Knaik
An 1D ISIS model has been constructed for the River Knaik and its tributaries to help assess and identify potentially suitable areas for riparian planting. The model cross sections have been developed from Nextmap DTM using ISIS Mapper. The models cross sections are typically spaced at 75m with a normal depth downstream boundary condition based on a typical slope of 1 in 100.
The model has been run in steady state for the 1 in 2, 50 and 200 year return periods. The flows for each return period are included in Table 49. The flows have been assessed using the Revitalised Flood Hydrograph methodology with catchment descriptors being extracted from the Flood Estimation Handbook CD V3.
Water course Return Period Flow
River Knaik 1 in 2 17.1
1 in 50 25.3
1 in 200 33.3
Corriebeagh Burn 1 in 2 13.2
1 in 50 19.5
1 in 200 23.7
Arrevore Burn 1 in 2 16.8
1 in 50 24.8
1 in 200 32.7
Table 49: Hydrological inflows for the model based in the ReFH methodology
Flood maps have been generated using NextMap DTM on a 5m grid. Generally NextMap has a vertical accuracy of approximately 1m. ISIS software (ISIS Mapper) was used to generate flood maps for the three return periods as presented in Figure 39, Figure 40 and Figure 41.
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Figure 39: Estimated1 in2yr flood extent on the River Knaik
Figure 40: Estimated 1 in 50yr flood extent on the River Knaik
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Figure 41: Estimated 1 in 200yr flood extent on the River Knaik
7.3 Identification of riparian planting opportunities
A parallel approach was taken to identify riparian planting opportunities within the River Knaik catchment:
i) GIS based analysis of ground surface slopes within the identified floodplain
ii) Site based reconnaissance
7.3.1 Desk based GIS analysis of riparian opportunities
In order to identify suitable areas for riparian planting a GIS analysis has been used. The criteria for the identification were as follows:
• Areas of land that have been identified as frequently flooded, i.e. 1 in 2 year return period
• Land with a typical slope of flatter than 1 in 50, ideally and with little vegetation, in order to facilitate an increase in roughness on the floodplain
Four main areas have been highlighted as strong riparian planting opportunities as shown in Figure 42:
• The Corriebeagh Burn, approximately 100m upstream of the confluence with the Allt an-t Seilich
• The River Knaik adjacent to Langside
• Allt an-t Seilich approximately 100m upstream of the confluence with the Corriebeagh Burn.
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• The Arrevore Burn approximately 200m upstream of the confluence with the River Knaik
Figure 42: Potential riparian planting areas identified using the 1 in 2 year flood extent. Flooded areas with a slope flatter than 1 in 30 have a medium potential while areas with a slope of flatter than 1 in 50 have a good potential.
7.3.2 Site based reconnaissance identification of riparian improvement opportunities
A site walkover survey was undertaken to identify potential opportunities for improving the River Knaik riparian corridor. The observations made on this site walkover survey are recorded on drawing WBAWPP029. In summary it was identified that:
• There are good pockets of riparian planting particularly in lower reaches of the River Knaik (Beanie Farm to Braco)
• Most reaches are not fenced on both sides of the watercourse and as a result livestock typically have access to both banks
• There is a notable absence of riparian vegetation in the upper catchment
• Where riparian vegetation is present the predominant riparian species are willow, birch and hazel
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• There was evidence that the existing riparian vegetation is managed such that large woody debris is removed from the watercourse, probably to reduce the probability of damage to local farm bridges
7.3.3 Minimising impact on wading birds
As presented in Section 2.5 much of the land surrounding the River Knaik riparian corridor is a good habitat for wading birds. Therefore, the riparian planting will need to leave areas / pockets of habitat for nesting birds. It has been assumed that at least a 100m buffer is required between the riparian planting and wading bird nesting areas to ensure that nesting birds are not overlooked by potential raptor roosts. It is recommended that short scrubby species are adopted for the riparian planting to reduce the impact on ground nesting birds.
7.4 Design of riparian restoration strategy
A riparian woodland planting strategy has been developed for the River Knaik by an experienced landscape architect. The concept design is presented in drawings WBAWPP-AL9001 to WBAWPP-AL005. These have been developed sufficiently to permit detailed consultation with stakeholders and potential funding bodies.
In developing the design the following aspects have been considered:
• The retention or improvement of existing views and landscape character;
• The likely ground conditions and the suitability of species within those ground conditions;
• The maintenance of access routes; and
• The minimisation of the impact on good agricultural land in the area.
The design proposes the use of four planting types:
• Birch Woodland/Scrub – predominately Downy Birch and Grey Sallow
• Alder Ash Woodland – predominately Alder, Ash, Downy Birch, Common Hawthorne, Grey Sallow and Hazel
• Oak-Birch Woodland with Blaeberry – predominately Common Oak and Silver Birch with Bilberry ground cover
• Hedgerow and hedgerow trees – predominately Hawthorne with Beech, Blackthorn and Elder.
The planting strategy has been developed to focus on the use of shorter scrubby woodland species to minimise the risk of blockage of downstream bridges and to reduce the impact on ground nesting birds. The selection of these scrubby woodland species is in keeping with the pioneer species found.
The riparian woodland planting strategy extends to the bridge serving Glenlichorn. Downstream of Glenlichorn potential infill pockets of riparian planting and poor riparian fencing has been identified during site based reconnaissance. These observations have been recorded in drawing WBAWPP029. The opportunities for the generation of flood risk management
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benefits and other benefits such as environmental service is significantly less in this area than upstream of Glenlichorn.
It is proposed that all planting will be to BS3936 and will be in accordance with the National Plant Specification. Where feasible all planting should be completed using stock of local provenance.
As observed during site visits, there is a high prevalence of deer in the area. This high density did not appear to have a detrimental impact on the natural regeneration of trees where agricultural land practices permitted woodland regeneration. Throughout the catchment there are few deer fences to protect commercial woodland or crops. It may be appropriate to install deer fencing around the proposed riparian planting however this may be unacceptable due to costs, visual impact or be overly restrictive for access. Therefore it may be more appropriate to use ordinary stock proof fencing and protect trees individually using guards. All fencing should be to BS 1722.
7.5 Utilities
Utility records have been secured from a number of local utility providers in the River Knaik area:
• Scotland Gas Networks has reported that Scotland Gas Networks have no apparatus within the River Knaik catchment (note presence of other gas pipelines)
• Scottish and Southern Energy has reported that there is a wide range of electricity transmission lines within the catchment. The principle risk is an overhead 11kV line that runs along the southern side of the B823 between Braco and Langside, all plant accessing the River Knaik would need to pass beneath this line. A spur of this 11kV line also crosses the River Knaik to serve Glenlichorn. A 33kV line crosses the River Knaik close to Ardoch Mill and high voltage pylons crossing the catchment close to Braco. It is understood that the proposed Denny-Beauly Interconnector crosses the catchment between Beannie and Langside.
• BT indicated that there is a buried service line along the B823 between Braco and Langside. It is not envisaged that this line will be affected by the works but its presence should be highlighted to contractors undertaking future works.
• Scottish Water reports that there are no Scottish Water assets, drainage or supply, in the River Knaik catchment. All properties along the B823 have private water supplies and septic tanks.
• National Transmission System has reported that a buried high-pressure gas main crosses through the lower catchment close to Over Ardoch. This is a significant pipeline and it is pertinent that any earthworks near this pipeline are managed accordingly.
• Virgin Media has responded that there is no Virgin Media plant in the area of service enquiry (effectively the entire catchment at Greenloaning).
Drawing WBAWPP031 shows the location of all identified utility plant within the River Knaik catchment.
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7.6 Landownership
The River Knaik riparian corridor is primarily owned by two estates:
• Braco Castle Farm
• Drummond Estate
Previous consultation with these landowners identified that they were in principle open to improvements to the riparian corridor provided the correct financial incentives were in place. The specific extents of ownership are currently unknown however it is understood that the Braco Castle Estate owns the southern bank of the Knaik to the confluence of the Corriebeagh Burn and the Drummond Estate owns the upper catchment and the northern bank to beyond Greensares.
The land ownership of the northern bank of the Knaik in the area of Beannie Farm is unknown. Site based reconnaissance has identified that this area of unknown ownership is in a relatively good condition already and therefore it is not a priority.
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7.7 Progression of restoration on the Allan Water between Greenloaning and Blackford
There are a number of potential barriers and constraints to the progression of this option as a pilot or flagship project at this time:
• The Shelforkie Moss Special Area of Conservation is in close proximity to the Allan Water in places. Changes to the Allan Water are likely to lead to changes in the groundwater within the designated area. It is anticipated that these changes would be positive and assist in restoring the currently degraded designated habitats.
• The South Tayside Goose Roosts Special Protection Area and RAMSAR is in relatively close proximity to the Allan Water however it is anticipated that the restoration of the Allan Water would have no impact on the designation.
• The Carsebreck and Rhynd Lochs Site of Special Scientific Interest is in close proximity to the Allan Water. This designation covers the goose population in the lochs, the surrounding grazing habitats and the Shelforkie Mosses.
• The close proximity of the Allan Water to the Stirling – Perth railway line
• The interests of landowners. Currently the Allan Water forms a boundary between two landowners.
• The interests of local fisheries. Despite its relatively poor condition of this reach of the Allan Water it is understood that the reach is used as spawning habitat by salmon.
To assist in the removal of the potential environmental designation barriers and constraints a screening consultation has been commenced with Scottish Natural Heritage (SNH). An initial response from SNH has been provided in Appendix C. In summary, provided key mitigation measures are undertaken and the opportunity to include enhancement works to the Shelforkie Moss SAC is taken, the restoration of this reach of the Allan Water could have a positive net benefit to the existing designations.
To facilitate consultation with the local landowners it is proposed to develop a conceptual design of the restoration of the Allan Water. This would provide a non-technical overview of the techniques that could be employed and an insight into what the reach might look like following restoration.
A similar consultation process has been entered into with Network Rail regarding the restoration of the Allan Water in this area. However at the time of writing there has been no formal response. It may be easier to progress this consultation with Network Rail once the conceptual design is in place.
Once these barriers are removed it is hoped that the restoration of the Allan Water between Greenloaning and Blackford, or a proportion of it, would form an excellent demonstration or flagship natural flood management project for the wider catchment strategy.
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8 Future structure and funding opportunities
8.1 Introduction
In order to ensure the implementation of the Allan Water natural flood management strategy it is necessary to address the following key areas:
• Scope of the future NFM programme;
• Which body will lead the NFM programme; and
• How the NFM programme will be funded.
These key areas are discussed in the following sections.
8.2 Progression
In developing the strategy it is important that the best elements of previous natural flood management projects are adopted:
• Pickering Forest – A strong communications strategy that has enthused locals to become involved
• Pontbren – A community lead initiative that has benefited greatly from donations in kind such as time, materials, skills, and land
• Eddleston Water – A catchment focused initiative with clear objectives and a good means of working with all stakeholders
It is recommended that the natural flood management strategy for the Allan Water is delivered by a range of initiatives and projects grouped together to form a programme. In some cases these may be formal projects that are centrally planned and implemented. Conversely, other projects may be relatively informal community group or land manager led initiatives. The large formal projects are likely to entail flagship activities such as restoration reaches on the main stem of the Allan Water. Large flagship projects will present good opportunities to increase awareness of the strategy to local people, but ultimately the cost associated with a top down approach is likely to curtail achievements. Instead it is preferable to instigate local enthusiasm through high quality demonstration projects and clear communication of objectives. A grassroots up approach will enable a much larger number of smaller projects to be pushed forward in keeping with the diffuse principles of effective catchment restoration and natural flood management. These low-level community projects will be able to benefit from much wider streams of funding including donations in kind such as the provision of labour, land and materials.
It will be necessary to have a strong heart to the programme that will be responsible for providing direction and enthusing locals to get involved. This central body will also be responsible for overseeing the implementation of pilot projects and may have a leading role in the implementation of the larger projects. To facilitate grassroots projects it will be necessary for the central body to, where possible, minimise the burdens on these smaller projects be that assisting in applying for funding, applying for statutory consents, undertaking monitoring or providing technical guidance.
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8.3 Leadership of the implementation
It is recommended that responsibility for the implementation is passed to a body whose objectives and remit are aligned with the benefits generated by the strategy. It is also important to give due consideration to the powers which the body might already hold such as the Permitted Development Rights held by Local Authorities. Consideration should also be given to the body’s ability to generate funding, its reputation and its capacity to generate enthusiasm. A summary of the identified bodies that could lead the programme are summarised in Table 50.
In summary there is no ideal body to take forward the progression of the project. It is recommended that the following organisations are consulted to ascertain interest in taking on the central programme leadership role:
i) Stirling Council
ii) Perth & Kinross Council
iii) Allan Water Angling Association and River Forth Fisheries Trust
The development of a body with a similar remit to the Tweed Form is potentially the most progressive means of implementing natural flood management measures within the catchment. This could represent a good model for the application to other catchments or areas across Scotland. It would be desirable to align the geographic extent (and remit) of this new body with either the existing WFD sub-districts or the Local Plan Districts setup to implement the Flood Risk Management Act. The Scottish Government should also be consulted prior to the formation of a new body to assist in aligning the structure with future policy.
It is envisaged that the remit of the lead organisation in implementation of the natural flood management programme will contain the following core items:
• The identification and promotion, or assisting in the promotion, of natural flood management opportunities within the catchment;
• Undertaking the proposed monitoring; and
• Providing advice to landowners and developers in the catchment.
It may be desirable to set measurable targets at the time of agreeing the lead organisation’s remit.
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Leadership option Benefits Disbenefits
SEPA -Current project leader - If SEPA is involved in the implementation of the project -Has the technical knowledge then there will be expectations for it to be involved in similar future projects. Desirable to promote a model that will work in future scenarios - Likely to form a difficult starting position with many of the landowners who view SEPA as a regulator - SEPA has no statutory responsibilities for undertaking project on the ground and is hence outside SEPA’s funding remit
Stirling Council -Has duties to manage flood risk in the - Doesn’t have influence, or permitted development lower catchment where the majority of rights, in the upper catchment where most of the flood benefits are accrued measures would be implemented -Access to central government funds -Other benefits such as environmental and social benefits are probably a lower priority to council flood protection unit
Perth & Kinross Council -Other than flood benefits the largest - No driving interest to reduce flood damages in the lower potential to generate other benefits is in the catchment. upper catchment -Other benefits such as environmental and social benefits - Permitted Development rights are probably a lower priority to council flood protection -Access to central government funds unit
Local fisheries - An existing catchment focused group -Risk of pursing sport fishing in preference for more (Possibly AWAIA or - Interests of group are consistent with general ecological, WFD or NFM improvements RFFT) NFM and WFD objectives -Has limited links to non-riparian land managers -Loss of accountability to central government
Creation of new body -Remit of new body could be aligned with - Would require the formation of a new body (similar to Tweed Forum) the objectives of NFM and WFD -Issue of how this body would be funded
National Farmers Union - Existing well respected body with good - May heighten the belief that farmers will pay the price of Scotland links to farmers NFM - Unlikely that the NFUS will want to take on the role - Loss of accountability to central government
Forestry Commission - Interests are aligned with NFM -If FCS has a central role in this project there may be Scotland (e.g. Pickering) anticipation that it has a similar role in future projects -Limited extent of land controlled by FCS in catchment
Community group -Well placed to make use of volunteers and -The Allan Water catchment is a large area with a number (similar to Pontbren) donations in kind of discrete communities associated with the various towns and villages -Loss of accountability to central government
National charity -A number of Natura2000 designations are -Loss of accountability to central government (RSPB or National Trust in a degraded state -Unlikely that these bodies will be interested in taking for Scotland) -Significant opportunities for landscape ownership of the implementation of the strategy scale environment improvements -Well placed to make use of volunteers and donations in kind
Table 50: Summary of the potential future project leaders
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8.4 Future management structure
It is recommended that a robust governance structure with a clear mandate is put in place to give the implementation of natural flood management in the Allan Water the best chance of success. To give implementation structure and direction it is recommended that it is treated as an ongoing programme made up of a series of discrete projects. Although the PRINCE2 project management system can often be seen as bureaucratic and laden with jargon it presents a clear and widely accepted mechanism for managing projects and in this case a challenging programme. It is used by many UK government departments and represents a de facto standard for government projects in the UK; hence it is advisable that the principles of PRINCE2 are applied to this programme.
PRINCE2 recommends the appointment and formation of a number of roles and groups when forming a project or programme, these are discussed in the following sections. By giving those involved in the project clear roles it is hoped that a more efficient structure can be put in place avoid ambiguities, duplication and omissions. It is not proposed to place an increased bureaucratic burden on projects; rather it is proposed to adopt best practice by ensuring that the correct structure is in place from the start.
8.4.1 Programme Board
A Programme Board has already been created for the Allan Water Natural Flood Management programme in the form of the Steering Group. This existing board could be retained or modified as the programme moves into the next phase. If the programme leadership is passed to a new forum style body then this body’s board could form the Programme Board. Assuming it is acceptable to the current members of the Steering Group the group’s members could form the Board.
8.4.2 Programme Executive
The Executive will have overall responsibility for ensuring that a project meets its objectives and delivers the project benefits. This individual will ensure that the focus, that it has clear authority, and that the work is actively managed. As chair of the Programme Board it is important that they hold sufficient influence with all the key stakeholders. It is recommended that the Programme Executive belongs to the Lead Organisation and it would be advantageous for them to be the line manger or equivalent of the Programme Manager.
8.4.3 Senior User
The Senior User will sit on the Programme Board and will be accountable for ensuring that the Users’ needs are specified correctly and that solution meets those needs correctly. The wide range of beneficiaries to the programme will result in a wide range of bodies that might be considered as Users. Hence, with the exception of the Programme Manager this is potentially one of the most challenging roles to fill. The Senior User might be appointed from one of the following organisations:
• Perth & Kinross Council
• Stirling Council
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• SEPA
• Scottish Government
In order to best represent the interests of the Users it is recommended that the Senior User does not come from the Lead Organisation.
8.4.4 Programme Manager
The Programme Manager will have the most significant role to play in the implementation of the programme. To many they will be the public face of the programme and its success will be dependent on the enthusiasm and abilities of this individual. This role will need to be undertaken by someone within the Lead Organisation.
The Programme Manager will have three primary functions:
• Facilitating and promoting natural flood management projects;
• Overseeing the monitoring programme; and
• Facilitating the flow of information not only between the Programme Board and Project Teams but also in the dissemination of information to the wider public and other stakeholders.
This individual will need to have a broad understanding of all of the environmental, hydrological and morphological specialities involved in natural flood management but strong communication skills and financial acumen will be their most important facets.
8.4.5 Project Boards
In some cases it is appropriate for the Programme Board to undertake the role of Project Board particularly for the larger flagship projects that are likely to be managed by the Programme Manager. There will be a need that a scaleable approach is adopted when setting up Project Boards and it should be recognised that some projects will be outside the direct control of the Programme Board. It is important that these projects outside the direct control of the programme are well run so that the project is able to meet its objectives and be a success. It is not essential for these projects to be overtly PRINCE2 compliant and it will be the responsibility of the Programme Manager to provide guidance if it becomes apparent that a project might fail to meet its objectives due to a lack of organisation. A project will not be excluded from the programme for simply differing substantially from the norm or for not overtly complying with PRINCE2.
Some examples of Project Boards are provided in Section 8.4.8.
8.4.6 Project Managers
In some cases it is anticipated that the Programme Manager will undertake the role of Project Manager, particularly for the implementation of the pilot demonstration projects but possibly also for larger flagship projects. It is envisaged that many projects will be managed by individuals other than the Programme Manager. These could include activities such as a farmer planting a riparian margin using SRDP funding, local fisheries improving fish passage or a
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Local Authority breaching flood embankments. As with the Project Board it will be the Programme Manager’s responsibility to intervene if it is evident that a project might fail to meet its objectives due to a lack of organisation. A project will not be excluded from the programme for simply differing substantially from the norm or for not overtly complying with PRINCE2.
Some examples of project managers are provided in Section 8.4.8.
8.4.7 Task delivery teams
It is envisaged that the natural flood management programme will consist of a large number of projects of varying sizes. These projects could vary between a land manager creating an improved riparian margin, a Local Authority undertaking a large-scale reach restoration project or the formation of community woodland by a local community group.
It is recommended that consideration is given to how technical guidance is supplied to inexperienced teams or organisations that become involved in the programme. It may be desirable to appoint specialists within the Lead Organisation to provide this guidance or appoint an appropriate consultant.
Some examples of task delivery teams are provided in Section 8.4.8.
8.4.8 Example Project Delivery Structures
The diverse nature of the projects which might form part of the wider Allan Water natural flood management programme will lead to large variation in the project structure. Some examples are provided below:
• Planting of 4Ha of native woodland by a small farmer – the farmer could fulfil all the roles of the Project Board in addition to managing the project and undertaking the work. Some informal guidance on funding could be provided by the Programme Manager. The farmer need not be aware of the formal names for the roles he is undertaking.
• Planting of 4Ha of native woodland by a small community group – ideally the community group’s own committee would undertake the role of the Project Board or a sub-committee might be formed. A member of the community group would be appointed to oversee or manage the project. The community group may then assign individual tasks such as securing funding, agreeing land agreements and tree planting to willing members of the community. The community group need not be aware that they are complying with the PRINCE2. If it becomes apparent that the group is failing to meet its project objectives then the Programme Manager may need to offer guidance on how to structure the group to give the best possible chance of success. Throughout the project the Programme Manager will be on hand to provide support and guidance.
• Changes to upland land management practices for a 200Ha site by a large estate – the estate board may undertake the role of Project Board with the implementation of the project being formally delegated to the estate manager and the estate’s own labour force undertaking the necessary tasks.
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• Floodplain restoration by a Local Authority – the Local Authority could treat it as an ordinary council-led flood risk management project. Specific tasks could be undertaken by consultants appointed under existing term commissions, council staff or appointed contractors. There would be no need for any deviations in procedure.
• Channel restoration of a 3km reach lead by the lead body – it is likely that a large flagship project will be managed by the Programme Manager and overseen by the Programme Board. Selected tasks of the project may be undertaken by the organisations that make up the Programme Board including the Programme Manager. It may be necessary to appoint a consultant to lead the design, assist in securing consents and assist in the procurement and supervision of a contractor to undertake the works.
8.5 Potential funding opportunities
The issue of funding is probably one of the largest and most significant factors for the successful implementation of the strategy. To increase the range of funding streams which can be employed it is recommended that the strategy is progressed as a programme made up of a wide range of discrete projects. The funding for each project will be dependent on not only the nature of the project but also the body that is promoting it. For example the funding mechanisms open to Local Authorities will be very different to those available to a local charity or action group. It should be noted that successful natural flood management and river restoration are dependent on diffuse works at a catchment scale as much as high profile reach scale intervention.
Care is required when arranging matched funding as many of the funds place restrictions on which funds they can be matched with. For example an EU fund cannot be matched against another EU fund, similarly Scottish Government funds cannot be paired. It may be feasible to work around the matching limitations through careful definition of each of the projects going into the wider restoration programme. A summary of the identified funding sources are presented in Table 51.
The funding mechanisms for the next phase of the Allan Water natural flood management programme are presented in the following sections:
• Funding of the River Knaik riparian restoration pilot project – Section 8.5.1
• Funding of the wider Allan Water programme - Section 8.5.2
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Fund Eligibility Nature of projects Award criteria Other information Value
EU LIFE+ Government Bodies & LIFE+ Nature and Biodiversity strand is Projects must help implement Next deadline for £0.5m-£5m NGOs probably most applicable. It focuses on European Policies and proposals is July 2011. the implementation of the EU directives Directives. on the conservation of habitats and of wild birds, as well as further strengthening the knowledge needed for developing, assessing, monitoring and evaluating EU nature and biodiversity policy and legislation.
Local Authority Local Authority projects Flood risk management, social, At the discretion of the Local Variable capital funding environment & economic projects Authority
Water Any project which can At the discretion of the body who owns At the discretion of the body This is not a formal Currently £0 abstractors in attract the attention of a or operates the abstraction. Principally who owns or operates the fund and only catchment water user in the projects which improve the quality or abstraction represents money catchment reliability of the water abstraction which might be available
Carbon offset Any project which can Projects which involve the creation of At the discretion of the carbon There are a range of Variable companies attract the attention of a carbon sinks offset company companies out there carbon offset company
Scottish Rural Public Sector, Improve Business viability Projects must fulfil criteria laid NB. SRDP is partly Variable Development Landowners, voluntary Enhance Biodiversity and Landscape out in the SRDP and meet local funded by the EU. Typically 70% for Programme & charities Improve Water Quality priorities set out by Regional It cannot therefore be woodland creation (including Project Assessment Committees Tackle Climate change matched to other EU packages LEADER) (RPAC) funds. Support Rural Communities LEADER is managed through LAGs (Local Action Groups)
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Fund Eligibility Nature of projects Award criteria Other information Value
Heritage Due to size of the Usually larger scale applications that Project must satisfy the Two stage process. £50,000 or more Lottery Fund monies available, more address nature conservation, historic following Strategic Aims: Project development for main grant Heritage Grants suitable to large building restoration, museum 1. Enable people to learn about grants, and mentor Up to 95% grant charitable organisations, collections, and objects or sites relating to their own and others’ heritage, support available rate government bodies etc. the UK’s industrial, transport or (Learning) between stages one maritime history. 2. Conserve the UK’s diverse and two. heritage. (Conservation) To find out if you 3. Enable more people to take project is suitable you part in and make decisions can complete a pre about their heritage application form and send it to your local
office who will then contact you.
Heritage Partnerships Aims to promote heritage conservation Requires a balance of Natural, To find out if you £250k to £2m Lottery Fund representing a range of as an integral part of rural regeneration cultural and built heritage. project is suitable you Landscape heritage and community can complete a pre Partnership interests. application form and send it to your local office who will then contact you.
Heritage Mainly Local Restoration and regeneration of historic Projects should also enhance To find out if you £250k to £5m Lottery Fund Authorities, although parks and gardens public access and may involve project is suitable you Parks for non-profit organisations improving facilities can complete a pre People that own public park application form and can apply send it to your local office who will then contact you.
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Fund Eligibility Nature of projects Award criteria Other information Value
Central Any organisations or The fund is intended to support the Projects will be judged Fund is able to support Total grant fund is Scotland Green individuals that can development and implementation of competitively against each other up to 100% of eligible £750k Network demonstrate they are early projects delivering the Green and only those projects that are capital and revenue (CSGN) delivering CSGN Network on the ground. judged to be of highest priority costs. Development priorities within the will be supported. Fund proposed CSGN activity Only open to projects located in area the Stirling Council area
SEPA Water Application would be • restoring natural processes in rivers or Projects must deliver Rolling deadlines for Total fund value Environment strengthened if the lochs improvements to wetlands, applications, last in of £1m Restoration application included • removal or modification of man-made rivers, lochs/ponds, estuaries or November for 2011/12. Fund activities which would barriers to improve fish passage and coasts; contribute towards Money must be spent improve the WFD status sediment transport achieving Water Framework before end of March in of a degraded • restoration of flood plains, coastal Directive (WFD) objectives; and the same financial year. watercourse, i.e. intertidal zones and wetlands where possible, deliver a wider removal of barriers to range of environmental, social • scoping studies to assess costed fish passage and economic benefits. options for restoration works
Scottish Community groups, Supports projects that get more people Projects must meet one or more Applicants are advised Small grants up to Natural voluntary groups and communities actively involved in of the following priorities: to contact their local £10,000 Heritage NGOs, other caring for Scotland’s nature and • Supporting opportunities for SNH office or e-mail Larger grants over organisations and landscapes. people to appreciate and enjoy [email protected] £10,000 private individuals. Under £10,000 grants – for projects the outdoors to discuss any projects looking for between £1,000 and £9,999. • Encouraging volunteering seeking 2011-12 funding. These projects should be no longer than • Supporting opportunities to 12 months. learn about the natural heritage £10,000 and over grants – for projects • Supporting community looking for £10,000 or more. development
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Fund Eligibility Nature of projects Award criteria Other information Value
Landfill Varies between funds Varies between funds. Typically focus Criteria varies between funds. The LCF is a collection Some funds up to Communities on the regeneration of contaminated sites Typically projects within 5- of funds administered £500k Fund (range of and the restoration of habitats. 10miles of an active landfill site by landfill site funds) operators. www.entrust.org.uk
Ardoch “Groups which are Environment and community At the judgment of the Ardoch Further information Total fund value Development active in the involvement projects Trust available at of £12,000 Trust community” (Braco and www.ardochtrust.org. Greenloaning) uk
Esmée Registered charity or Supports work that focuses on the UK’s Criteria is very flexible, as long Grants towards project Unknown Fairbairn properly constituted cultural life, education, the natural as project fits into current and core costs. These Foundation organisation environment and enabling people who priorities include running costs are disadvantaged to participate more such as staff salaries fully in society. and overheads. Funding split between Main Grants and Strands (Currently Biodiversity, Museum & Heritage collections and New Approaches to Learning.) Includes potential funding for research.
Tubney UK Registered charities Environmental conservation of benefit to Currently unidentified Unknown Charitable the whole community. Conservation of Trust the natural environment through achievement of UK BAP Targets for practical action.
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Fund Eligibility Nature of projects Award criteria Other information Value
Gannochy Charitable organisations Projects promoting access to the Currently unidentified Scotland Only, with Unknown Trust countryside and natural environment, Preference to Perth and including paths, cycleways and environs. waterways. Educational projects connected with countryside and heritage-related activities. Projects promoting training and volunteering in conservation, restoration and preservation work. Green spaces in urban areas and community woodlands.
Dulverton Charitable organisations The Trust is keen to support the general Currently unidentified Major Grants Trust conservation and protection of wildlife average £25k habitats within the United Kingdom. They also encourage projects concerning the sympathetic management of trees and native woodlands. Projects concerned with single species are rarely considered.
Waterloo Charitable organisations Current priorities are: Currently unidentified No upper or lower Unknown Foundation • Forests and links to CO2. limit but unlikely to • Marine protection fund >£100k
Table 51: Potential funding streams for the implementation of natural flood management measures in the Allan Water. This table is largely based on information supplied by Jason Watts, SNH External Funding Advisor, and has been produced with his kind permission.
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8.5.1 Funding of the River Knaik riparian restoration pilot project
In conjunction with the steering group it has been identified that the most applicable pilot project is the improvement of the riparian corridor on the River Knaik. This project comprises of two main elements:
i) Extensive riparian planting in the upper catchment near the confluence of the Corriebeagh Burn and Arrevore Burn with the River Knaik.
ii) Improvements in riparian fencing with scattered infill riparian planting opportunities.
It is envisaged that the most appropriate means of funding these activities is SRDP funding either led by the landowner or via the use of the LEADER option. A summary of the funding priorities consistent with the restoration of the River Knaik riparian corridor identified by Tayside area are presented in Table 52. In summary it is believed that the riparian restoration on the Knaik shows good correlations with the fund’s priorities. It may be feasible to supplement this funding via local fisheries or RAFTS for the installation and renewal of riparian fencing.
An alternative approach of using SEPA Restoration Fund could be considered, however it is unclear whether the restoration of the River Knaik’s riparian corridor would improve it WFD status.
There is a second alternative of applying for Heritage Lottery Funding for the restoration of the River Knaik’s riparian corridor between Braco and Beanie/the Falls of Braco. This reach of the watercourse is an unused recreational asset in the area. The extension of the existing path network along the river to the Falls of Braco could provide a valuable public amenity for the area in addition to increasing the local awareness of the water environment while also providing biodiversity improvements through riparian planting, riparian fencing and the installation of roosting boxes. In addition to providing opportunities to inform visitors on flooding and biodiversity the trail could link in with the area’s cultural heritage at the former Ardoch Mill and the Roman Fort to the north of Braco. When viewed together these components may present a relatively strong Heritage Lottery Fund application.
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Region Description Priority Code
TAY08 "A halt in the loss of biodiversity and reverse previous losses through targeted action". Activities that restores, conserves or enhances Biodiversity Action Plan (BAP) for example: through maintenance and enhancement of ancient, long established and semi-natural woodlands, restoration of Plantations on Ancient Woodland Sites (PAWS), particularly where ancient plant communities are most at risk; organic conversion or organic maintenance; and, actions in Local Biodiversity Action Plans. -restore or enhance habitats and species for which Tayside is a significant stronghold and also identified as being of priority in the BAPs
TAY10 Viable populations of rare and/or endangered species, through improved conservation of the 32 species listed for priority action in the Species Action Framework for Scotland, and through targeted action identified in priority Species Action Plans. Particularly proposals that: -maintain or improve viable populations of the 14 species listed for priority action in the Species Action Framework and which occur in Tayside - Red Squirrel, Capercaillie, Black Grouse, Great Crested Newt, Wildcat, Water Vole, Freshwater Pearl Mussel, Lesser Butterfly Orchid, Small Cow-Wheat, Pearl Bordered Fritillary, Intermediate Wintergreen, Hen Harrier, Native Deer, and Woolly Willow.
TAY12 Increase in the area of connected natural habitats and ecological features, through collaboration between land managers to adopt a landscape scale, whole ecosystem approach to helping biodiversity, particularly where the threat from climate change is most acute, or, offering desirable species the opportunity to increase their range by taking advantage of changing climatic factors. For example, by expanding the area of native woodland in preferred locations. Particularly proposals that: -follow the principles of Forest Habitat Networks for woodland expansion and recovery in line with the existing plans for Forest Habitat Networks in Tayside including montane scrub and riparian woods -apply the principles used for FHN to other types of habitat networks to deliver specific and regional benefits -river basin management plans via collaborative cross-unit management of priority riparian habitats -support wider habitat links such as hedgerows and high-altitude tree lines -contribute to the connectivity of habitats in the Tayside LBAP, including hedgerows and treelines.
TAY13a The safeguarding and enhancement of the diverse character of rural landscapes. -encourage collaboration that enhances landscape character in recognised landscape partnerships areas.
TAY13b Enhanced experience, understanding and enjoyment of the landscape. Particularly proposals that: -enhance key views from public roads, access routes and public open spaces
TAY13c High quality design in both new build and natural elements that enhance and strengthen the landscape character of an area. Particularly proposals that: -enhance the landscape character in recognised landscape partnerships areas with collaborative projects that will deliver landscape-scale benefits.
TAY14 An increased contribution to the diversity and character of landscape form Scotland's woods and forests, through restructuring planted woodlands, particularly through the use of Low Intervention Silvicultural Systems, and diversification of a range of well designed woodland types in the preferred areas, as identified in regional Indicative Forestry or Woodland Strategies or in line with Forest Habitat Networks, particularly the improvement of degraded or unsightly local environments. Particularly proposals that:: -support woodland management and expansion along the lines of the Forest Habitat Network potential for Tayside previously undertaken by FCS and SNH
Allan Water Natural Flood Management Techniques and Scoping Study
TAY16 Reduced diffuse pollution from rural land uses. Particularly proposals that: -support actions where applicants are proposing water quality improvements with appropriate water and soils, plans and nutrient budgets demonstrating how the options proposed address identified risks and opportunities. Such proposals should take account of priorities for action identified in the Tay and other River Basin Management Plans
TAY17 Improved water quality of surface water and ground water bodies supported by a 'Soils and Water Plan', with priority given to actions in Nitrate Vulnerable Zones, Bathing Water Catchments and Drinking Water Protected Areas.
TAY18 Achieve good ecological status for water bodies which are currently classified as being at less than good ecological status. This can be achieved through priorities identified in River Basin Management Plans, particularly proposals that: -support actions identified as priorities by the Tay and other associated River Basin Management Plans in Tayside, which will help water bodies which are currently classified as being at less than good ecological status, to achieve that status by 2015
TAY19 Sustainable flood management and reduced flood risk (including adaptation to climate change), through appropriate land management, particularly actions identified in River Basin Management Plans. -seek support for actions to manage and mitigate against flood risk across Tayside by adopting appropriate land and river flow management practices which demonstrably reduce flood risk in flood prone areas including 'managed retreat' on flood plains.
TAY21 Improved carbon sequestration, through conservation of soil organic matter, e.g. through organic conversion or maintenance, and, expansion of woodlands (in preferred areas identified in regional Indicative Forestry Strategies or Woodland Strategies) where such contribute towards meeting targets in Scotland's Climate Change Programme contribute towards meeting targets in Scotland's Climate. Particularly proposals that: -support the creation of new well-designed multi-purpose woodlands in Tayside optimising carbon sequestration in line with the draft P&K IFS and proposed Local Woods and Forestry Framework for Angus -support the expansion of native woodlands in line with the Forest Habitat Network for Tayside as identified by FCS and SNH as well as the draft P&K IFS and proposed Angus Local Woods and Forestry Framework
Table 52: Summary of the SRDP funding priorities in the Tayside area that are applicable to the restoration and improvement of the riparian corridor on the River Knaik
8.5.2 Funding of the wider Allan Water programme
It is recommended that a stable source of funding is identified to cover the costs associated with setting up and managing the implementation of the Allan Water natural flood management programme. There are a number of potential funding mechanisms to achieve this but the most effective is likely to be a multi-year award via SEPA’s Restoration Fund. This fund could be used to cover the salaries and overhead costs of the team responsible for running the programme. It would be the responsibility of the team to secure suitable funding for each of the projects or to assist the bodies promoting the projects to secure funding. It is feasible that the restoration funding could be supplemented by funding from the Esmée Fairbairn Foundation and/or the Ardoch Development Trust.
As the programme progresses it may be feasible to access EU Life funding or Heritage Lottery Funding for a collection of projects. The value of funding available by these streams could permit large flagship projects such as the restoration of the main stem of the Allan Water between Greenloaning and Braco and/or the restoration of the lower River Knaik.
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In progressing the programme it should be remembered that its success is not dependent on point interventions within the catchment. Therefore it is essential that the funding for diffuse land management changes and the restoration of minor tributaries is given consideration alongside the funding of high profile flagship projects.
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9 References
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iii) Bennett S.J. et al Using simulated emergent vegetation to alter stream flow direction within a straight experimental channel. Geomorphology, Elsevier 2002
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v) Faulkner D., Flood Estimation Handbook Vol2: Rainfall frequency estimation. Institute of Hydrology, 1999.
vi) Forestry Commission Scotland, Developing native woodland habitat networks. Natural Scotland.
vii) Forth District Salmon Fishery Board & River Forth Fisheries Trust, A Fisheries Management Plan for the Forth Catchment. June 2009.
viii) Hawkes H.A., Origin and development of the Biological Monitoring Working Party score system. Water Research, Vol 32, No.3, pps 964-968
ix) Houghton-Carr H., Flood Estimation Handbook Vol 4: Restatement and application of the Flood Studies Report rainfall-runoff method. Institute of Hydrology, 1999.
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xi) Natural Resources Conservation Service, Stream Restoration Design National Engineering Handbook, Chpt 12. United States Department of Agriculture, 2007.
xii) Penning-Rowsell et al. The Benefits of Flood And Coastal Risk Management: A Manual of Assessment Techniques. Flood Hazard Research Centre, 2010.
xiii) Revisions to Economic Appraisal Procedures Arising from the New HM treasury ‘Green Book’.
xiv) Robson A. & Reed D, Flood Estimation Handbook Vol 3: Statistical procedures for flood frequency estimation. Institute of Hydrology, 1999.
xv) Scottish Environment Protection Agency, Supporting Guidance (WAT-SG-34) Assessing the significance of impacts – Social, Economic and Environmental. October 2009.
xvi) Scottish Government, Flood Risk Management (Scotland) Act. 2009.
xvii) Soil Conservation Service. Urban Hydrology for Small Watersheds TR-55. USDA, 1986.
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xviii) SPON’s Civil Engineering and Highways Price Book” (SPON Press, 2010). xix) Thorne CR, Soar P, Skinner K, Sear D, Newson M. (2010) Driving processes II. Investigating, characterising and managing river sediment dynamics. In Sear D, Newson MD, Thorne CR (Eds) Guidebook of applied fluvial geomorphology. Tomas Telford Limited, London.
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