THE UNIVERSITY of HULL Outcomes of River Rehabilitation On
Total Page:16
File Type:pdf, Size:1020Kb
THE UNIVERSITY OF HULL Outcomes of river rehabilitation on instream hydraulics and fish communities being a Thesis submitted for the Degree of Doctor of Philosophy in the University of Hull by Michelle Anne Smith B.Sc. (Hons.) (Hull), M.Sc. (Hull) October 2013 LIST OF CONTENTS LIST OF FIGURES V LIST OF TABLES IX LIST OF PLATES XIII ACKNOWLEDGMENTS XIV ABSTRACT XV 1 CHAPTER ONE: GENERAL INTRODUCTION 16 1.1 Aims and objectives 19 2 CHAPTER TWO: A REVIEW OF THE ROLE OF RIVER PROCESSES AND FISH PHYSICAL HABITAT IN RIVER REHABILITATION TO ACHIEVE E.U. WATER FRAMEWORK DIRECTIVES 21 2.1 River form and function 22 2.2 Scale 26 2.3 Fish species requirements 30 2.3.1 Brown trout 32 2.3.2 Community composition 36 2.3.3 Eel 36 2.3.4 Stone loach 38 2.3.5 Bullhead 39 2.3.6 Lamprey 39 2.4 Habitat assessment 40 2.4.1 HABSCORE 41 2.5 Pressures 44 2.5.1 Channelisation and river engineering 45 2.5.2 Weirs and dams 46 2.5.3 Climate change 48 2.6 The Water Framework Directive 48 2.7 River rehabilitation 49 2.8 Measures 52 2.8.1 Installation of gravels to the channel bed 52 2.8.2 Weir removal 53 2.8.3 Channel narrowing 56 2.9 River rehabilitation goals 56 2.10 Monitoring and evaluation 57 2.11 Conclusions 59 3 CHAPTER THREE: GENERAL MATERIALS AND METHODS 61 3.1 Sites selected 61 3.2 Details of sites and river rehabilitation projects surveyed 63 3.2.1 Small-scale weir removal in the River Dove, Derbyshire 63 3.2.2 Installation of gravels in the River Stiffkey, North Norfolk 82 3.3 General Methodology 88 3.3.1 Data processing 97 3.3.2 Data analysis 98 ii 4 CHAPTER FOUR: DETERMINING THE PHYSICAL OUTCOMES OF RIVER REHABILITATION IN TERMS OF INSTREAM HYDRAULICS 103 4.1 Results 103 4.1.1 Small-scale weir removal from the River Dove at Dovedale 103 4.1.2 Small-scale weir removal from the River Dove at Hartington 110 4.1.3 Channel narrowing at Lowthorpe Beck, East Yorkshire 116 4.1.4 Installation of gravel riffles in the River Stiffkey, North Norfolk 120 4.2 Discussion 131 4.3 Conclusions 136 5 CHAPTER 5: DETERMINING THE RESPONSE OF FISH COMMUNITY COMPOSITION TO RIVER REHABILITATION 138 5.1 Results 138 5.1.1 Small-scale weir removal at Dovedale on the River Dove 138 5.1.2 Small scale weir removal from the River Dove at Hartington 141 5.1.3 Channel narrowing in Lowthorpe Beck at Harpham 144 5.1.4 Installation of gravel riffles in the River Stiffkey, North Norfolk 147 5.2 Discussion 151 5.3 Conclusions 157 6 CHAPTER SIX: ASSESSING FISH COMMUNITY STRUCTURE AND LINKAGES WITH INSTREAM HYDRAULICS AND PHYSICAL HABITAT. 159 6.1 Results 159 6.1.1 Habitat availability for all life stages of brown trout 159 6.1.2 Influence of environmental parameters on fish species captured 161 6.1.3 Relationships between descriptors of community composition and environmental parameters 161 6.1.4 Habitat Use 166 6.2 Discussion 167 6.3 Conclusions 183 7 CHAPTER 7: GENERAL DISCUSSION 184 7.1 Weir removal from the River Dove at Dovedale 185 7.2 Weir removal from the River Dove at Hartington 186 7.3 Channel narrowing at Lowthorpe Beck, East Yorkshire 187 7.4 Gravel installation at the River Stiffkey 187 7.5 The influence of hydraulic conditions on fish community composition 188 7.6 The importance of monitoring 189 7.7 Conclusion and Recommendations 193 iii REFERENCES 196 APPENDIX 1. HABFORM 210 APPENDIX 2. FLOW DURATION CURVES (1990-2011) (DATA SOURCE: ENVIRONMENT AGENCY) 213 APPENDIX 3. HISTORICAL FISH CATCH DATA FROM ENVIRONMENT AGENCY RECORDS 216 iv LIST OF FIGURES Figure 2.1: An example of a hydrograph showing natural flow variation for maintaining river channel form and function (Cowx, unpublished). 23 Figure 2.2: Functional Units in fish ecology (Cowx and Welcomme, 1998). 24 Figure 2.3: Physical biotopes and functional (meso) habitats. (From Newson and Newson, 2000). 28 Figure 2.4: Complexity of abiotic interactions affecting salmon and trout parr (from Armstrong 2003) 31 Figure 2.5: Diagram showing the lifecycle of Salmo. Trutta (Brown Trout) (after: http://www.wildtrout.org/content/trout-lifecycle on 18/07/2013). 32 Figure 2.6: A diagrammatic description of the most successful river rehabilitation projects modified from Palmer et al. (2005). 57 Figure 3.1: Location and description of surveyed river rehabilitation sites. 62 Figure 3.2: Long-term hydrograph of the River Dove. (Data source: Environment Agency). 65 Figure 3.3: Hydrograph of the River Dove throughout the survey period. Arrows indicate survey dates (Data source: Environment Agency). 65 Figure 3.4: Location of weir removal site on River Dove, Dovedale. Red markers indicate the location of the weir. Map created and modified using Digimap, January 2012. 67 Figure 3.5: Spatial arrangement of sampled sites at River Dove, Dovedale (not to scale). 69 Figure 3.6: Location of weir removal site on River Dove, Hartington. The red marker indicates weir location. Map created and modified using Digimap, January 2012. 73 Figure 3.7: Spatial arrangement of surveys sites at River Dove, Hartington (not to scale). 74 Figure 3.8: River Hull Headwaters SSSI 75 Figure 3.9: Hydrograph of Foston Beck at Foston Mill throughout 1990-2011 (Data source: Environment Agency). 76 Figure 3.10: Hydrograph of Foston Beck at Foston Mill throughout the survey period. Arrows indicate survey dates (Data source: Environment Agency). 77 Figure 3.11: Location of survey sites on Lowthorpe beck at Harpham. Red markers indicate site location; Site three is the site of channel narrowing. Map created and modified using Digimap, January 2012. 80 v Figure 3.12: Spatial arrangement of surveyed sites at Lowthorpe Beck, Harpham (not to scale). 81 Figure 3.13: Hydrograph of the River Stiffkey, 1990-2011 (Data source: Environment Agency). 83 Figure 3.14: Hydrograph of the River Stiffkey throughout the survey period. Arrows indicate survey dates. 84 Figure 3.15: Location of survey sites on River Stiffkey. Red circles indicate site location; site four shows the only area of naturally occurring gravels in the reach. Map created and modified using Digimap, January 2012. 86 Figure 3.16: Schematic representation of spatial location of surveyed sites at River Stiffkey, North Norfolk (not to scale) 87 Figure 4.1: Mean depth at each site in the River Dove at Dovedale. 104 Figure 4.2: Mean flow velocity at each site in the River Dove at Dovedale. 105 Figure 4.3: Mean flow velocity at each site in the River Dove at Dovedale. 106 Figure 4.4: Mean width at each site in the River Dove at Dovedale. 107 Figure 4.5: MDS plot of similarity between sites in the River Dove at Dovedale. 110 Figure 4.6: PCA plot of hydraulic variables within sites in the River Dove at Dovedale. 111 Figure 4.7: Mean depth at each site in the River Dove at Hartington. 112 Figure 4.8: Mean flow velocity at each site in the River Dove at Hartington 113 Figure 4.9: Mean Froude numberat each site in the River Dove at Hartington. 114 Figure 4.10: Mean width at each site in the River Dove at Hartington. 115 Figure 4.11: Similarity of sites in the River Dove at Hartington. 116 Figure 4.12: PCA plot of hydraulic variables within sites in the River Dove at Hartington 116 Figure 4.13: Mean depth at each site in Lowthorpe Beck, East Yorkshire. 117 Figure 4.14: Mean flow velocity at each site in Lowthorpe Beck, East Yorkshire. 118 Figure 4.15: Mean Froude number at each site in Lowthorpe Beck, East Yorkshire. 119 Figure 4.16: Mean width at each site in Lowthorpe Beck, East Yorkshire. 120 Figure 4.17: Similarity of sites in Lowthorpe Beck, East Yorkshire. 121 Figure 4.18: PCA plot of hydraulic variables within sites in Lowthorpe Beck, East Yorkshire. 121 Figure 4.19: Mean depth at each site in the River Stiffkey, North Norfolk. 123 Figure 4.20: Mean flow velocity at each site in the River Stiffkey, North Norfolk 124 Figure 4.21: Mean Froude number at each site in the River Stiffkey, North Norfolk. 125 vi Figure 4.22: Mean width at each site in the River Stiffkey, North Norfolk. 126 Figure 4.23: Similarity of sites in River Stiffkey, North Norfolk 130 Figure 4.24: PCA plot of hydraulic variables within sites in River Stiffkey, North Norfolk 131 Figure 5.1: Percentage species composition at Dovedale before, after and one year after weir removal weir removal. 139 Figure 5.2: Shannon Weiner diversity index (black bars) and species evenness (broken line) at Dovedale before, after and one year after weir removal. 139 Figure 5.3: Total fish density (black bars) and species richness (broken line) at Dovedale before, after and one year after weir removal. 140 Figure 5.4: MDS plot of similarity of fish species between sites. 141 Figure 5.5: Percentage species composition at Hartington before, after and one year after weir removal. 142 Figure 5.6: Shannon Weiner diversity index (black bars) and species evenness (broken line) at Hartington before, after and one year after weir removal. 143 Figure 5.7: Total fish density (black bars) and species richness (broken line) at Hartington before, after and one year after weir removal. 143 Figure 5.8: MDS plot of similarity of fish species between sites.