Preface

Ken J. Gregory

Visiting Professor University of Southampton and, Emeritus Professor University of London, London, UK

When I was appointed to the Chair of Physical Geography in the University of Southampton in 1976 I asked my Exeter research students if they wished to move with me or preferred to stay at the University of Exeter. The one research student who decided to move was Geoff Petts - surprising in some ways because he had already completed two years research so the move would be for his final writing-up year. Although I thought that it was a good idea to get experience of two universities, I had not influenced Geoff's decision, but later realised that this was typical of his subsequent career - the ability to see the potential as opportunities became available.

A foundation

Geoff had graduated from the University of Liverpool in 1974 with a joint honours degree in Physical Geography and Geology. The NERC studentship at the University of Exeter that we had obtained for research on river channel adjustments downstream from reservoirs was the second of a series awarded for investigations of river channel adjustments arising from a range of different causes. The empirical approach employed used field measurements of channel capacities downstream from dams in 13 areas throughout England and Wales to compare with the dimensions of unregulated channels. At that time there had been comparatively few such investigations, and indeed the effects of human activity on river channels had not been explicitly explored until classic papers by Wolman (1967a,b; see Gregory, 2011), although scour below dams had been surveyed by engineers as a necessary input to dam construction. The Tone had been investigated (Gregory and Park, 1974) but the results obtained by Geoff from a range of UK areas greatly extended understanding of changes that could occur. Areas studied included the Derbyshire Derwent where, in addition to comparing the size of channels downstream from reservoirs with channel size along unregulated rivers showing that capacities were reduced to c. 40% of the expected size, Geoff also demonstrated how a bench formed within the channel had produced the reduction in capacity and that dendrochronology could be used to date trees that had grown on the benches. This allowed confirmation that the reductions in capacity had occurred at dates corresponding to reservoir construction.

This research (Petts, 1978) was one of a series of NERC studentship investigations which deliberately focused on the national picture so that instead of concentrating on a single field area, then very popular with the growth of process-based investigations, the intention was to address large-scale problems by employing empirical measurements from several different areas of Britain. Such an approach was demanding for a research student, but Geoff demonstrated his ability to apply himself to the opportunity, assembling the literature context from the international publications, undertaking field surveys upstream and downstream from reservoirs in different areas of the country, then proceeding to identify the significance of event effectiveness, of sediment availability, of vegetation indicators, culminating in establishing the appropriate elements of a general model including relaxation paths of complex response. This resulted in an impressive array of papers dealing with the channel change effects downstream of the Derwent dams (Petts, 1977), with the application of complex response to channel morphology adjustments (Petts, 1979), with the range of channel changes in regulated rivers (Petts, 1982) and with implications for stream habitats (Petts, 1980a) introducing a link with aquatic ecology that was subsequently to feature throughout Geoff's later research. At a time when specific applications of research results were not often considered, he appreciated the potential significance of the research results for management (Petts, 1980b) which were considered in relation to long-term consequences (Petts, 1980c).

Having established his publication record so effectively, Geoff then had the vision to produce a book Impounded Rivers (Petts, 1984a) - which he described as the 'outcome of seven years of research and discussion with friends and professional colleagues'. This book was notable in that it contained hydrology, water quality, morphological effects, ecological aspects including vegetation and macroinvertebrates as well as fisheries, thus providing a truly multi-disciplinary approach to management problems and prospects that were the subject for the final chapter. This book demonstrated the value of providing a context and approach, which we would now refer to as holistic, to succeed the preceding engineering emphasis. In the final part of the preface to his book, Geoff made a plea for a long-term perspective in river management (Petts, 1984a, xv), a theme which he has pursued in much of his later work.

Explanation of the detail of his early research is necessary because it shows how these foundations were fundamental for the way in which he has been able to develop his career. After gaining his PhD he was first appointed in 1977 to the Dorset Institute of Higher Education (later to become part of the University of Bournemouth), but then in 1979 was appointed as lecturer in geography University of Loughborough where he remained until 1994, being senior lecturer (1986-89), Professor of Physical Geography (1989-94) and head of Geography (1991-94). In 1994 he was appointed Professor of Physical Geography University of Birmingham becoming Director of Environmental Science and Management (1994-97), he founded the University's Centre for Environmental Research and Training (CERT) in 1996, became Director of Environmental Science and Training in 1997, Head of the School of Geography and Environmental Science from 1998-2001, and then Pro-Vice Chancellor from 2001-07. With this background and progression it was perhaps inevitable that a move to lead an institution would follow, and in 2007 Geoff became Vice Chancellor and Rector of the University of Westminster. On taking up his post he said 'I am particularly looking forward to working in partnership with staff, students and other stakeholders to grow the University's contributions to the emerging economic, social and environmental demands of urban life in London and other cities across the globe'.

Research development and impacts

A career involving progressively greater amounts of administration, at Loughborough, Birmingham and Westminster, could have led to a decline of further research, publication and scientific impact, but Geoff has proved to be one of those individuals who maintains his academic contacts. His contributions can be encapsulated in terms of his developing research on flow regulation, the books and contributions in edited volumes that he has produced, and the establishment of the journal Regulated Rivers. Furthermore, by pursuing these three themes he has produced enlightening general perspectives, has established collaboration with many other scientists, including many international colleagues, especially European.

Research on flow regulation continued with investigations of a number of other areas leading to the context of flow regulation impacts, progressing research towards other themes. Further investigations of morphological change included the lowland English river Ter, Essex (Petts and Pratts, 1983) and the Rheidol in Wales (Petts and Greenwood, 1985). Whereas ecological changes had previously often been analysed independently from morphological changes, Geoff was involved in research combining the two (e.g., Petts and Greenwood, 1985) and also provided important dimensions such as timescales for ecological change (Petts, 1987). Although changes in water quality and reduced sediment transport downstream of dams had previously been investigated, Geoff was involved with analysis of monitored results from a controlled release from Kielder reservoir on the North Tyne (Petts et al., 1985), analysed sedimentation along the Rheidol (Petts, 1984) and bar development along the North Tyne (Petts and Thoms,1987). Although ecology and its relation to morphological changes had been major sections of his book (Petts, 1984) other aspects were subsequently explored including invertebrate faunas (Petts and Greenwood, 1985), the macroinvertebrate response and physical habitat change to river regulation on the River Rede (Petts, Armitage and Castella, 1993), and the effects of water abstractions on invertebrate communities in UK streams (Castella et al., 1995). Such specific investigations allowed elaboration of more general ecological concerns such as a perspective on the abiotic processes sustaining the ecological integrity of running waters (Petts, 2000), dams and geomorphology (Petts and Gurnell, 2005), a scientific basis for setting minimum ecological flows (Petts et al., 1995), and reservoir operating rules to sustain environmental flows in regulated rivers (Yin, Xin'an et al., 2011).

Flow regulation research led to evaluations of water resources such as the case of Lake Biwa, Japan (Petts, 1988), in turn leading naturally to concern for management problems such as the management of fish populations in Canada (Petts et al., 1989), advancing science for water resources management (Petts et al., 2006), linking hydrology and biology for assessing water needs for riverine ecosystems (Petts et al., 2006), the role of ecotones in aquatic landscape management (Petts, 1990), and sustaining the ecological integrity of large floodplain rivers (Petts,...