REGULATED RIVERS: RESEARCH zyxwvuts & MANAGEMENT, VOL. zyxwvu 12, 347-351 (1996) REMEDIAL STRATEGIES IN REGULATED RIVERS: INTRODUCTORY REMARKS CHRISTER NILSSON zyxwv Riparian Ecology Group, Department zyxwvut of Ecological Botany, Umed University, S-901 87 Umed, Sweden AND JOHN E. BRITTAIN Freshwater Ecology and Inland Fisheries Laboratory (LFI), Zoological Museum, University of Oslo, Sars gate zy 1. N-0562 Oslo, Norway ABSTRACT This paper summarizes recent examples of measures to remediate the ecology of regulated and fragmented rivers in boreal and temperate regions. The catchment area is suggested as the most appropriate scale and framework for such measures. Suitable measures may include reinstatement of flooding and productivity levels, management of nuisance growth of aquatic macrophytes, rehabilitation of depauperate riparian zones, increased habitat diversity, stocking of fish and construction of bypass channels for fish migration. Finally, an overall approach zyxw to remedial measures is pro- posed in which they form part of an integrated catchment management for regulated rivers. KEY zyxwvutsrqponml WORDS: regulated rivers; remedial measures INTRODUCTION The purpose of these proceedings is twofold. Firstly, we wish to document current work on remedial measures in regulated rivers, presented during the workshop ‘Remedial Strategies in Regulated Rivers’ in Lycksele, Sweden, 25-28 September 1995. Secondly, we wish to provide a basis for developing an integrated programme for remedial strategies in regulated rivers. Although many ideas could be generally applicable, the primary focus will be on boreal and temperate regions. The general idea of remedial approaches to rivers that are fragmented and regulated by dams has not received general acceptance until quite recently. The majority of the world’s rivers are regulated (Dynesius and Nilsson, 1994), and these developments have considerably changed landscape structure and processes, and led to an impoverishment of natural diversity (Ward and Stanford, 1995). When these developments were made, little attention was paid to the ecological changes in rivers and their surroundings. However, an increasing environmental awareness, expressed in general goals such as ‘sustainable develop- ment’ and ‘biodiversity’, has created a will to rehabilitate damaged rivers. Nevertheless, this is not an easy task. There are two major problems: firstly, although remedial approaches are likely to favour interests such as fishing and nature conservation, many may also cause problems for major current water uses such as elec- tricity production and navigation. It is primarily a political question which way to choose. Secondly, the his- tory of hydrological disruption has engendered much indignation about the negative effects on river ecology, and fostered an irreconcilability towards hydropower exploitation. An opinion quite commonly expressed among environmentalists is that hydroelectric rivers shouZd be severely damaged, not least as a warning against further exploitation. The rationale of this reasoning is that measures to rehabilitate damaged rivers might be used as an argument to proceed with new, ‘environmentally friendly’ hydropower development in yet unexploited rivers. Given that few major rivers still remain free flowing throughout their entire length (Dynesius and Nilsson, 1994), this would be a very controversial scenario. Irrespective of the different feelings that are generated by remedial measures in regulated rivers, we CCC 0886-9375/96/040347-05 zyxwvutsr 0 1996 by John Wiley & Sons, Ltd. Received 13 April 1996 Accepted 23 April 1996