Sources of Farm Pollution and Impact on River Quality
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Sources of Farm Pollution and Impact on River Quality Volume I WRc pic NRA National Rivers Authority Project Record 0 0 1 / 1 3/W Souces of farm pollution and impact on river quality G.P Rutt*, T Pickering*, D Woodrow, C Turner0 and C P Mainstone * Now with NRA Welsh Region + Now with NRA North West Region ° Now with NRA Northumbrian Region Research Contractor: WRc pic Henley Rd Medmenham Marlow SL7 2HD National Rivers Authority Rivers House Waterside Drive Almondsbury Bristol BS12 4UD NRA Project Record 001/13/W j I ENVIRONMENT AGENCY 010205 National Rivers Authority Rivers House Waterside Drive Almondsbury Bristol BS12 4UD Tel: 0454 624400 Fax: 0454 624409 © National Rivers Authority 1992 All rights reserved. No part of this document may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise without the prior permission of the National Rivers Authority. This report is the result of work jointly funded by the National Rivers Authority and the Scotland and Northern Ireland Forum for Enviornmental Research. Dissemination status Internal: Limited External: Restricted Research contractor This document was produced under R&D Contract 001 by: WRc plC Henley Rd Medmenham Marlow SL7 2HD Tel: 0491 571531 Fax: 0491 579094 WRc Report Na NR 3177/4206 NRA Project Leader The NRA's Project Leader for R&D Contract 001: F Jones - Welsh Region Additional copies Further copies of this document may be obtained from Regional R&D Co-ordinators or the R&D Section of NRA Head Office. Statement of use This document is intended as a comprehensive record of the field investigations and literature reviews undertaken within the project. It is intended for circulation to members of the NRA's Rural Land Use Group only. CONTENTS Page LIST OF TABLES iv LIST OF FIGURES x EXECUTIVE SUMMARY 1 KEY WORDS 1 1. INTRODUCTION 3 2. PROJECT DESCRIPTION 5 2.1 Objectives 5 2.2 Work programme 5 3. LITERATURE REVIEW OF THE IMPACT AND CONTROL OF FARM POLLUTION 9 3.1 Introduction 9 3.2 Nature of farm wastes 10 3.3 Sources of water pollution 18 3.4 Impacts of wastes on surface water quality 24. 3.5 Preventative strategies and remedial measures 28 3.6 Legislation and incentive schemes 42 3.7 International approaches to farm pollution control 44 3.8 Regional attitudes to farm pollution control in the U.K. 68 3.9 Discussion 75 4. NATIONAL ASSESSMENT OF FARM POLLUTION 81 4.1 Introduction 81 4.2 Methods 81 4.3 Results and discussion 90 i CONTENTS Cont'd Page 5. DEVELOPMENT OF RAPID APPRAISAL METHODS 119 5.1 An indicator system for West Wales (Spring) 119 5.2 An indicator system for Devon (Spring): 'Family' level 141 5.3 An indicator system for Devon (Spring): 'Species' level 156 5.4 An indicator key for West Wales (Summer) 170 6. TESTING AND RAPID APPRAISAL METHOD 179 6.1 Evaluation exercise in West Wales 179 6.2 Evaluation exercise in Devon 199 6.3 Evaluation exercise in Yorkshire 200 6.4 Evaluation exercise in Cheshire (NRA North-West Region) 213 7. INVESTIGATION OF POLLUTION PROCESSES 227 7.1 Pontfaen Brook: A chronic discharge of silage effluent 227 7.2 Study of the Nant Rhydw; silage effluent and parlour dairy washings 247 7.3 Nant Pibwr: yard run-off and parlour/dairy washings 275 7.4 Slurry transport studies 290 8. SALMONID RECOLONIZATION STUDIES 299 8.1 Introduction 299 8.2 Methods 302 8.3 Results 304 8.4 Discussion 315 ii CONTENTS Cont'd Page 9. RECOVERY OF STREAM COMMUNITIES FOLLOWING STIMULATED INCIDENTS 323 9.1 Introduction 323 9.2 Methods 325 9.3 Field investigations 332 9.4 Conclusions 353 REFERENCES 359 The following Appendices will be found in Volume II APPENDICES APPENDIX A LIST OF PARTICIPANTS IN THE NATIONAL ASSESSMENT EXERCISE APPENDIX B FARM POLLUTION QUESTIONNAIRE USED IN THE NATIONAL ASSESSMENT EXERCISE APPENDIX C EXPLANATORY NOTES ON THE FORM OF POLLUTION INCIDENT DATA REQUESTED FOR THE NATIONAL ASSESSMENT EXERCISE APPENDIX D ESTIMATION OF WASTE LOADINGS AND POLLUTION RISK FROM LIVESTOCK APPENDIX E RECENT NWC DOWNGRADINGS DUE WHOLLY OR PARTIALLY TO FARM POLLUTION APPENDIX F DEVELOPMENT OF RAPID APPRAISAL METHODS i n CONTENTS Cont'd APPENDIX G TESTING OF RAPID APPRAISAL METHOD APPENDIX H INVESTIGATION OF POLLUTION PROCESSES APPENDIX I SALMONID RECOLONIZATION STUDIES iv LIST OF TABLES Page 3.1 Mean chemical content of cattle slurry (Suss 1989a) 12 3.2 Copper, zinc and cadmium levels in slurry (from van Erp and Smilde 1989) 18 3.3 Problems of incorrect applications of slurry (Hojovec 1989) 34 3.4 Percentage nitrogen lost to leaching from slurry applied to crops and grassland (Archer personal communication) 35 3.5 Maximum livestock numbers per hectare of land available for slurry spreading, as proposed by EC Directive COM(88)708 46 3.6 Maximum application rates of slurry/manure to land in the Netherlands (Dutch Commodity Board for Feeding Stuffs (DCBFS) 1989) 48 3.7 Prohibitions on land application of slurry/manure in the Netherlands (Baset et al. 1990) 48 3.8 Maximum numbers of livestock allowed on a single farm in Switzerland (Swiss Government 1987, Strauch 1989) 56 3.9 Guidelines on land characteristics for the disposal of slurry in Switzerland 58 3.10 Restrictions on the land application of slurry in four German states 60 v LIST OF TABLES Cont'd Page 5.1 Data sets classified using TWINSPAN. Number of taxa includes percentage cover of sewage fungus entered as a separate variable 125 5.2 Relationships between TWINSPAN groups from the four analyses and biotic and environmental variables 128 5.3 Relationships between TWINSPAN groups from data set SPP1 and biotic and environmental variables 129 5.4 Biological characteristics of stream sites in West Wales arranged by TWINSPAN group 134 5.5 Frequency of occurrence of selected invertebrate taxa in the three TWINSPAN groups generated by analysis of the SPP1 data set 138 5.6 Relationships between TWINSPAN groups at first level of division and environmental and biotic variables 147 5.7 Product-moment correlation coefficients between first axes derived from DECORANA and biotic and environmental variables 151 5.8 Relationships between TWINSPAN groups at the second level of division and environmental and biotic variables 152 5.9 Biological characteristics of stream sites in Devon arranged by pollution group 153 5.10 Relationships between TWINSPAN groups and environmental and biotic variables for the Devon Spring data set 162 vi LIST OF TABLES Cont'd 5.11 Frequency of occurrence of selected invertebrate taxa in the three TWINSPAN groups 5.12 Biological characteristics of stream sites in Devon arranged by pollution group 5.13 Relationships between TWINSPAN groups and environmental and biotic variables for the Welsh Summer Indicator Key 5.14 Biological characteristics of stream sites sampled in West Wales in July 1991, giving possible pollution sources 6.1 Characteristics of the study catchments grouped by Pollution Control Area 6.2 Pollution groups and polluting farms grouped by catchment and pollution control area 6.3 Relationship between pollution groups indicated by original indicator key (three groups) and biotic indices 6.4 Relationship between pollution groups indicated by revised indicator key (five groups) and biotic indices and environmental variables - West Wales, Spring 1991 6.5 Progress with programme of farm visits as of 30 August 1991 6.6 Progress with programme of farm visits as of 12 February 1992 6.7 Breakdown of sites surveyed in West Wales by catchment and indicator key group LIST OF TABLES Cont'd Page 6.8 Relationship between pollution groups indicated by revised indicator key (five groups) and biotic indices and environmental variable - West Wales, Spring 1992 196 6.9 Sites where biological quality clearly reflected success or otherwise of remedial measures taken on farms upstream 197 6.10 Relationship between pollution groups indicated by the West Wales indicator key (five groups) and biotic indices and environmental variable - Devon, Spring 1992 201 6.11 Relationship between indicator key group and biotic indices and environmental variable across the three catchments in Yorkshire 204 6.12 Characteristics of sites sampled on 10/3/92 in the Sutton/Willow Beck catchment grouped by indicator key group 205 6.13 Macroinvertebrate families recorded on 10/3/92 at sites on Sutton Beck grouped by indicator key group 207 6.14 Characteristics of sites sampled on 10/3/92 in the Danby Beck catchment grouped by indicator key group 208 6.15 Macroinvertebrate families recorded on 10/3/92 at sites on Danby Beck grouped by indicator key group 211 6.16 Characteristics of sites sampled on 11/3/92 in the Earby Beck catchment grouped by indicator key group 213 6.17 Macroinvertebrate familes recorded in 11/3/92 at sites on Earby Beck grouped by indicator key group 214 viii LIST OF TABLES Cont'd Page 6.18 Relationships between indicator key group and biotic indices across the three catchments in Cheshire 219 6.19 Characteristics of sites sampled on 17/3/92 in the Upper Weaver catchment grouped by indicator key group 220 6.20 Macroinvertebrate families recorded at sites on 17/3/92 in the Upper Weaver grouped by indicator key group. Logarithmic abundance categories are shown (1=1-9, 2=10-99, 3=100-999 etc.) 220 6.21 Characteristics of sites sampled on 17/3/92 in the River Duckow catchment grouped by indicator key group 221 6.22 Macroinvertebrate families recorded on 17/3/92 at sites on the River Duckow grouped by indictor key group. Logarithmic abundance categories are shown (1=1-9, 2=10-99, etc.) 223 6.23 Characteristics of