i IMPACTS OF FLOW REGULATION AND ARTIFICIAL FLOODS IN AN UPLAND STREAM ECOSYSTEM Benjamin Robert Gillespie Submitted in accordance with the requirements for the degree of Doctor of Philosophy The University of Leeds School of Geography November 2014 ii The candidate confirms that the work submitted is his own, except where work which has formed part of jointly authored publications has been included. The contribution of the candidate and the other authors to this work has been explicitly indicated below. The candidate confirms that appropriate credit has been given within the thesis where reference has been made to the work of others. Chapter 3 Publication title: A critical analysis of regulated river ecosystem responses to environmental flows from reservoirs Authors: Gillespie, Ben; University of Leeds, School of Geography/ Water@Leeds DeSmet, Simon; University of Leeds, School of Geography/ Water@Leeds Kay, Paul; University of Leeds, School of Geography/ Water@Leeds Tillotson, Martin; University of Leeds, School of Geography/ Water@Leeds Brown, Lee; University of Leeds, School of Geography/ Water@Leeds Publication: Freshwater Biology [in press] Work attributable to Ben Gillespie: Data collection (shared approximately 3:1 (Gillespie:DeSmet)), data quality control and analysis; project management; manuscript production. Work attributable to other authors: Data collection (shared approximately 3:1 (Gillespie:DeSmet)), advice; suggestions of improvements; proof reading. Chapter 8 Publication title: Effects of impoundment on macroinvertebrate community assemblages in upland streams Authors: Gillespie, Ben; University of Leeds, School of Geography/ Water@Leeds Brown, Lee; University of Leeds, School of Geography/ Water@Leeds Kay, Paul; University of Leeds, School of Geography/ Water@Leeds Publication: River Research and Applications [in press] Work attributable to Ben Gillespie: Data collection, quality control and analysis; project management; manuscript production. Work attributable to other authors: Advice; suggestions of improvements; proof reading. This copy has been supplied on the understanding that it is copyright material and that no quotation from the thesis may be published without proper acknowledgement. © 2014 The University of Leeds and Benjamin Robert Gillespie The right of Benjamin Robert Gillespie to be identified as Author of this work has been asserted by him in accordance with the Copyright, Designs and Patents Act 1988. iii ACKNOWLEDGEMENTS First of all, I would like to express my sincere gratitude to my supervisors, Dr Paul Kay and Dr Lee Brown for giving me the opportunity, inspiration and support to undertake what has been the most rewarding experience of my life. I would also like to thank Dr Martin Tillotson and Dr Jonathan Carrivick for their guidance and insight over the last three years. I would like to express my appreciation to Mark Tinsdeall, James Kitson, Simon Firth and all other staff at Yorkshire Water Ltd who have offered encouragement and support throughout this research. I am also incredible grateful to Yorkshire Water Ltd for funding this work. I would like to thank all staff at the University of Leeds, particularly David Ashley, Rachel Gasior, Chartell Bateman and Jacqui Manton for their support. Additionally, my gratitude goes to Ian Benson, Susan Watson, Andy Newton, Donna Cox, Matt Loewenthal, Matt Dibbs and Kevin Jaundrell for their roles in enabling my research. Thanks is also due to the developers of and contributors to R (r-project.org) and Apache OpenOffice (openoffice.org) who enabled elements of this research to occur without financial restriction. Most importantly, I would like to express my wholehearted thanks to Edgar and Karen Gillespie and Gemma King who gave me unwavering support. iv ABSTRACT Mitigation of ecological impacts associated with stream regulation is now a legislative priority and Artificial Floods have been suggested as a potential tool to achieve this aim. However, understanding of the impacts of stream regulation and Artificial Floods on downstream ecology is currently limited. This thesis provides detailed reviews of both of these topics and identifies key contemporary research priorities. These priorities were subsequently addressed through assessment of the impact of stream regulation and Artificial Floods on downstream hydrology, physical chemistry, coarse sediment transport and benthic macroinvertebrates in an upland sub- catchment of the River Humber, UK. Evidence that regulation was associated with significant impacts on hydrology (e.g. flood frequency, rate of change), physical chemistry (particularly flood pH and diurnal stream temperature range) and macroinvertebrates was identified, but impacts were found to vary spatially and temporally, indicating the importance of site specific and temporal factors. Control of hydrological characteristics was demonstrated during Artificial Floods which generally resulted in reductions of electrical conductivity, dissolved oxygen and pH and no change in stream temperature. Evidence for coarse sediment transport in line with overspill events prior to Artificial Floods was identified, but little evidence for change in macroinvertebrate assemblage was found. Evidence for the use of Artificial Floods as a management tool was greatest for coarse sediment transport and pH but overall, limited potential was demonstrated, bringing into question their validity as management techniques in some regulated streams and provoking requirement for further research. The findings of this thesis, methodological developments, conceptual advances and recommendations are therefore considered to have advanced the science and understanding of regulated stream management. Such progress is vital in this rapidly developing research field. v Table of Contents 1 INTRODUCTION...................................................................................................................1 1.1 Research context..............................................................................................................1 1.2 Research gaps, aims, objectives and hypotheses..............................................................2 1.2.1 Aims..........................................................................................................................2 1.2.2 Research gaps, objectives and hypotheses.................................................................2 2 THE IMPACT OF REGULATION ON DOWNSTREAM ECOSYSTEMS.......................8 2.1 Chapter overview..............................................................................................................8 2.2 Introduction......................................................................................................................8 2.2.1 The history of stream regulation................................................................................8 2.2.2 Contemporary extent of stream regulation...............................................................10 2.3 Impacts of regulation on downstream ecosystems.........................................................13 2.3.1 Hydrology...............................................................................................................13 2.3.2 Physical-chemical impacts......................................................................................17 2.3.3 Morphological impacts............................................................................................20 2.3.4 Biota........................................................................................................................25 2.4 Summary........................................................................................................................27 3 MITIGATION OF IMPACTS OF REGULATION USING ENVIRONMENTAL FLOWS ...................................................................................................................................................28 3.1 Chapter overview............................................................................................................28 3.2 Introduction....................................................................................................................28 3.3 Methods..........................................................................................................................29 3.3.1 Literature search......................................................................................................29 3.3.2 Data extraction and quality assessment...................................................................29 3.4 Results............................................................................................................................33 3.4.1 Qualitative analysis of assembled datasets..............................................................34 3.4.2 Quantitative analysis of assembled datasets............................................................37 3.4.3 Quality assessment..................................................................................................38 3.5 Discussion......................................................................................................................40 3.5.1 Spatial distribution of studies..................................................................................40 3.5.2 Flow and ecosystem response types........................................................................41 3.5.3 Qualitative and quantitative flow-ecosystem response relationships.......................42