ENVIRONMENT AGENCY North East Region SECOND INTERIM REPORT ON THE ENVIRONMENTAL IMPACTS OF THE DROUGHT ON YORKSHIRE’S RIVERS 1995-1996 December 1997 Frontispiece The Drought in Yorkshire River Wharfe in Langstrothdale, summer 1996 TABLE OF CONTENTS page EXECUTIVE SUMMARY.............................................................................................. 4 1.0 CATCHMENT SUMMARIES................................ ........................................................ 7 1.1 RiverAire................................................................................................................7 1.2 River Calder........................................................................................................... 9 1.3 River Don..............................................................................................................11 1.4 RiverHull..............................................................................................................14 1.5 RiverOuse.............................................................................................................16 1.6 RiverUre...............................................................................................................18 1.7 River Wharfe........................................................................................................20 2.0 PURPOSE....................................................................................................................... 23 3.0 BACKGROUND AND ISSUES....................................................................................24 4.0 METHODS AND ANALYSIS.......................................................................................30 4.1 General.................................................................................................................30 4.2 Hydrology and water resources........................................................................ 30 4.3 Water quality....................................................................................................... 31 4.4 River habitat surveys..........................................................................................32 4.5 Aquatic macro-invertebrates............................ .................................................32 4.6 Fisheries................................................................................ .....................:.......34 5.0 RIVER AIRE CATCHMENT........................................................................................36 5.1 Background and issues.......................................................................................36 5.2 Purpose.................................................................................................................36 5.3 Hydrology and water resources........................................................................37 5.4 Water quality.......................................................................................................38 5.5 Ecology................................................................................................................. 39 5.5.1 Aquatic macro-invertebrates................................................................39 5.5.2 Fisheries...................................................................................................40 6.0 RIVER CALDER CATCHMENT......... ...................................................................... 41 6.1 Background and issues.......................................................................................41 6.2 Purpose.................................................................................................................42 6.3 Hydrology and water resources........................................................................42 6.4 Water quality.......................................................................................................43 6.5 Ecology................................................................................................................. 46 6.5.1 Aquatic macro-invertebrates................................................................47 6.5.2 Fisheries...................................................................................................49 6.5.3 Agency fisheries actions.........................................................................51 f 1 7.0 RIVER DON CATCHMENT........................................................................................53 7.1 Background and issues.......................................................................................53 7.2 Purpose.................................................................................................................. 53 7.3 Hydrology and water resources........................................................................53 7.4 . Water quality........................................................................................................54 7.4.1 Changes and state of water quality........................................................ 54 7.4.2 Other water quality actions......................................................................55 7.5 Ecology.................................................................................................................. 57 7.5.1 Aquatic macro-invertebrates...............................................................58 7.5.2 Fisheries................................................................................................... 60 8.0 RIVERHULL CATCHMENT....................................................................................... 64 8.1 Background and issues.......................................................................................64 8.2 Purpose.................................................................................................................. 65 8.3 Hydrology and water resources........................................................................65 8.4 Water quality........................................................................................................66 8.5 Ecology...................................................................................................................68 8.5.1 Aquatic macro-invertebrates...............................................................68 8.5.2 Fisheries................................................................................................... 70 9.0 RIVER OUSE CATCHMENT.......................................................................................71 9.1 Background and issues.......................................................................................71 9.2 Purpose.................................................................................................................. 71 9.3 Hydrology and water resources........................................................................71 9.4 Water quality.................................................................... ...................................73 9.5 Ecology.................................................................................................................. 74 9.5.1 Macrophytes................................................................................................74 9.5.2 Aquatic macro-invertebrates...............................................................74 9.5.3 Fisheries................................................................................................... 79 10.0 RIVER URE CATCHMENT.........................................................................................82 10.1 Background and issues.......................................................................................82 10.2 Purpose.................................................................................................................. 82 10.3 Hydrology and water resources........................................................................83 10.4 Water quality....................................................................................................... 84 10.5 River habitat survey............................................................................................85 10.6 Ecology.................................................................................................................. 86 10.6.1 Macrophytes...............................................................................v...........86 10.6.2 Aquatic macro-invertebrates.............................................................. 87 10.6.3 Fisheries................................................................................................... 89 10.6.4 Birds......................................................................................................... 94 10.6.5 Mammals..................................................................................................96 2 RIVER WHARFE CATCHMENT................. ...98 11.1 Background and issues........................ .98 11.2 Purpose.................................................. ...98 11.3 Hydrology and water resources......... .99 11.4 Water quality:....................................... 101 11.5 Ecology................................................... 103 11.5.1 River habitat survey................ 103 11.5.2 Macrophytes............................. 103 11.5.3 Aquatic macro-invertebrates.. 105 11.5.4 Fisheries.................................... 110 10.6.5 Mammals................................... 119 KEY ISSUES & IMPACTS............................