THE UNIVERSITY of HULL Identifying Limitations of Monitoring
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THE UNIVERSITY OF HULL Identifying limitations of monitoring the success of river rehabilitation schemes for freshwater fish being a Thesis submitted for the Degree of Doctor of Philosophy in the University of Hull by Natalie Vivee Angelopoulos B.Sc. (Hons) (Hull 2007) M.Sc. (Hull 2008) October 2013 ii ACKNOWLEDGMENTS Firstly, I would like to thank the University of Hull for funding this study through the 80th Anniversary PhD Scholarship. I am also especially grateful to my supervisor Professor Ian Cowx for his guidance and encouragement during this study. Many thanks are also due to the following members of HIFI, Dr Jon Harvey, Dr Richard Noble, Dr Andy Nunn, Dr Jon Bolland, Dr Ryan Taylor, Dr Lauren Tewson, Michelle Smith, Sam Walton, Karen Twine, Andrea Robson, Marcela Portocarrero Aya, Marie Taylor and Sam Bartlett for their assistance in data collection. In addition, I would like to express my appreciation to the Environment Agency, Wild Trout Trust, East Yorkshire Chalk Rivers Trust, Trent Rivers Trust, National Trust, land and fishery owners for their cooperation throughout the course of this study. Finally, I would like to thank my parents Alex and Ann Angelopoulos and my sister Tania Angelopoulos who have helped me stay positive throughout the course of this study and to Tom Anderton for his understanding and patience over the years. iii ABSTRACT IDENTIFYING LIMITATIONS OF MONITORING THE SUCCESS OF RIVER REHABILITATION SCHEMES FOR FRESHWATER FISH Hydromorphological degradation impacts on habitat availability for biota in rivers. Degradation occurs as a consequence of multiple pressures driven by anthropogenic actions such as agriculture, urbanisation, industry, water supply, flood protection, navigation and transportation, fisheries and recreation. Rehabilitation of rivers is a tool that underpins the Water Framework Directive (WFD) by means of addressing river degradation by re-introducing habitat heterogeneity to impacted river systems. Many past and recent papers have highlighted a lack of information on the success of rehabilitation projects leading to a paucity of information and validation of the efficacy of such schemes. A review of 49 UK rehabilitation case studies found only 59% of these projects were monitored and worryingly only 24% of the 49 projects recorded any degree of success in the outcomes of the project. Clearly, there are limitations in monitoring the success of river rehabilitation schemes and it is this ‘key’ issue that is addressed in this thesis, to move from decisions based largely on subjective judgements to those supported by scientific evidence. A literature review was carried out to identify best practise knowledge of the key steps for designing effective project planning for river rehabilitation and identifying existing limitations, focusing specifically on monitoring design and impact assessment. In addition to the literature review, a number of small scale rehabilitation case studies were monitored and evaluated to give a practical insight into the limitations and constraints that arise, when measuring projects success. Fish were selected as the chosen biological indicator and were monitored in addition to a number of habitat variables to identify rehabilitation success. The following array of case studies were evaluated, listed in order of complexity: - Instream remediation of Driffield Beck, a small urban stream - Channel narrowing of Lowthorpe Beck, a Yorkshire chalk stream - Brash revetment to prevent bank erosion on the River Manifold - Small weir removals on the River Dove - Artificial riffle reinstatement on the River Stiffkey As climate change pressures become more frequent on river systems, it also becomes an important driver for river rehabilitation mitigation and adaptation strategies. The EU Floods Directive and UK Flood and Water Management Act need to be integrated with the EU WFD and Habitats Directive, to work towards flood risk management (FRM) whilst still considering river heath. This approach is still in its early stages and there are no examples in the literature that report successful FRM that has incorporated river rehabilitation. Two case studies from an urban river setting on the River Don in Sheffield provide a practical insight into the limitations of monitoring and evaluating case studies where FRM is combined with river rehabilitation on the local habitat and fisheries. Overall, monitoring was limited spatially and temporally for all case studies, this can be overcome by planning a suitable monitoring design before any rehabilitation takes place so long- term (pre and post), spatial monitoring can overcome natural variability. Furthermore, fish were a poor indicator for rehabilitation success over such a short monitoring timeframe; it is therefore advised that multiple biological quality elements are monitored to strengthen the evaluation of project success. Stocking of fish by the Environment Agency became a large hindrance when evaluating fisheries data for some of the case studies, because it masked changes that could have occurred as a result of rehabilitation. This is where the importance of communication between different stakeholders is vital, to reduce conflicting actions. Collaboration between FRM and conservation specialists is also necessary to achieve a win-win scenario and to endeavour to integrate these two conflicting objectives. There is much uncertainty when identifying rehabilitation success; current concepts in literature consider the application of endpoints and benchmarks against which to measure performance however, there are no definite criteria to date. Limitations, in monitoring and evaluating need to be overcome to establish appropriate targets for benchmarking and endpoints to reach project success. Furthermore, river restoration programme goals often only address problems on single rivers at a small scale and therefore have limited impact on catchment-scale processes. Potential benefits of implementing river rehabilitation and conservation at a catchment-scale are subsequently addressed. iv Table of Contents ACKNOWLEDGMENTS III CHAPTER 1. INTRODUCTION 1 1.1. Degradation of rivers 1 1.1.1. Key drivers of rehabilitation for rivers 4 1.2. Conservation of inland waters 5 1.2.1. Geomorphology of rivers & Ecosystem dynamics 6 1.3. Thesis Scope 10 CHAPTER 2. ASSESSING THE IMPACT OF RIVER REHABILITATION SCHEMES – A MISSING DIMENSION OR UNNECESSARY PROCEDURE? 12 2.1. Monitoring 20 2.2 Importance of monitoring within a project framework 21 2.1.1. Fish monitoring and habitat assessment methods 22 2.2.1 Spatial & temporal replication 22 2.3 Planning an impact assessment 25 2.3.1 Monitoring design 26 2.4 Importance of evaluation and transfer of knowledge 28 CHAPTER 3. IDENTIFYING LIMITATIONS FOR REHABILITATION SUCCESS 30 3.1. Introduction 30 3.2. Materials and methods 37 3.2.1. Fisheries and habitat survey methods 37 3.2.2. Data analysis 38 3.2.3. HABSCORE data collection and outputs 41 3.2.4. Impact assessment 42 3.3. Casestudy introduction 47 3.4. Instream remediation of Driffield Beck 49 3.4.1. Introduction 49 3.4.2. Methods 51 3.4.3. Results 51 3.4.4. Discussion 55 v 3.5. Channel narrowing of Lowthorpe Beck 58 3.5.1. Introduction 58 3.5.2. Methods 60 3.5.3. Results 60 3.5.4. Discussion 69 3.6. Brash revetment to prevent bank erosion on the River Manifold 71 3.6.1. Introduction 71 3.6.2. Methods 74 3.6.3. Results 74 3.6.4. Discussion 86 3.7. Effect of small weir removals on freshwater rivers 88 3.7.1. Introduction 88 3.7.2. Methods 89 3.7.3. Results 92 3.7.4. Discussion 106 3.8. Artificial riffle as a rehabilitation technique to improve spawning habitat for brown/sea trout 111 3.8.1. Introduction 111 3.8.2. Methods 113 3.8.3. Results 113 3.8.4. Discussion 125 3.9. General discussion 131 CHAPTER 4. FLOOD RISK MANAGEMENT OF AN URBAN RIVER – RIVERINE MITIGATION METHODS AND IMPLICATIONS FOR FISHERIES 133 4.1. Introduction 133 4.1.1. Policy 134 4.1.2. Integrating flood mitigation directives with conservation and rehabilitation 135 4.1.3. Aims and objectives 137 4.2. River Don Catchment 138 4.3. Malin Bridge case study 138 vi 4.3.1. Introduction 138 4.3.2. Background 139 4.3.3. Aims and objectives 140 4.3.4. Fish survey methodology 141 4.4. Results 142 4.4.1. HABSCORE 142 4.4.2. status of fish populations 143 4.4.3. Length frequency distributions 144 4.4.4. Impact assessment and resource calculation 156 4.5. Discussion 156 4.5.1. Recommendations 160 4.5.2. Nursery Street 163 4.5.3. Blonk Street 163 4.5.4. Effingham Street 163 4.5.5. Brightside 164 4.6. Materials and methods 167 4.6.1. Fisheries survey methodology 167 4.7. Data analysis 170 4.8. Results 171 4.8.1. Status of fish populations 171 4.8.2. Fish species length distribution 172 4.8.3. MDS and cluster analysis 193 4.9. Discussion 195 4.9.1. Importance of the availability for fish life stages within an urban river system 197 4.10. Rehabilitation in an urban river 200 4.11. Planning Monitoring & Assessment 201 4.12. Future works 202 CHAPTER 5. DISCUSSION 203 5.1. Limitations in monitoring river rehabilitation success 203 5.2. Benchmarking, endpoints and success 206 vii 5.3. Catchment planning rehabilitation 210 5.4. Urban river rehabilitation 216 5.5. Conclusion and recommendations 219 REFERENCES 222 APPENDIX 1. WFD HYDROMORPHOLOGY MITIGATION MEASURES: GROUPED BY PRESSURE (ROYAL HASKONING) 247 APPENDIX 2 – EFI+ DATABASE INFORMATION 254 viii TABLE OF FIGURES Figure 1.1 The four main ecological components that constitute river form and function (adapted from Mainstone & Holmes 2010) 6 Figure 1.2. Functional units for fish (taken from Cowx & Welcomme 1998). 8 Figure 2.1. An adaptive management framework flow diagram for river rehabilitation project planning. 16 Figure 2.2. Publication trends for evaluating stream rehabilitation containing the key words Topic=(river* OR floodplain OR stream OR riparian) AND Topic=(restor* OR rehab* OR mitig* OR conserv*), Topic=(river* OR floodplain OR stream OR riparian) AND Topic=(restor* OR rehab* OR mitig* OR conserv*) AND Topic=(evaluat* OR effectiv* OR assess* OR monitor*)(Web of knowledge completed April 2013).