26122 Water Resources and Environment Technical Note C.2 Environmental Flows: Case Studies Series Editors Richard Davis Rafik Hirji WATER RESOURCES AND ENVIRONMENT TECHNICAL NOTE C.2 Environmental Flows: Case Studies SERIES EDITORS RICHARD DAVIS, RAFIK HIRJI The World Bank Washington, D.C. Water Resources and Environment Technical Notes A. Environmental Issues and Lessons Note A.1 Environmental Aspects of Water Resources Management Note A.2 Water Resources Management Policy Implementation: Early Lessons B. Institutional and Regulatory Issues Note B.1 Strategic Environmental Assessment: A Watershed Approach Note B.2 Water Resources Management: Regulatory Dimensions Note B.3 Regulations for Private Sector Utilities C. Environmental Flow Assessment Note C.1 Environmental Flows: Concepts and Methods Note C.2 Environmental Flows: Case Studies Note C.3 Environmental Flows: Flood Flows Note C.4 Environmental Flows: Social Issues D. Water Quality Management Note D.1 Water Quality: Assessment and Protection Note D.2 Water Quality: Wastewater Treatment Note D.3 Water Quality: Nonpoint-Source Pollution E. Irrigation and Drainage Note E.1 Irrigation and Drainage: Development Note E.2 Irrigation and Drainage: Rehabilitation F. Water Conservation and Demand Management Note F.1 Water Conservation: Urban Utilities Note F.2 Water Conservation: Irrigation Note F.3 Wastewater Reuse G. Waterbody Management Note G.1 Groundwater Management Note G.2 Lake Management Note G.3 Wetlands Management Note G.4 Management of Aquatic Plants H. Selected topics Note H.1 Interbasin Transfers Note H.2 Desalination Note H.3 Climate Variability and Climate Change Copyright © 2003 The International Bank for Reconstruction and Development/THE WORLD BANK 1818 H Street, N.W., Washington, D.C. 20433, U.S.A. All rights reserved. Manufactured in the United States of America First printing March 2003 2 CONTENTS Foreword 5 Acknowledgments 7 Introduction 9 River Ecosystems and Environmental Flows 10 Rivers respond to both natural disturbances and man- made disturbances. In general, the more the flows are changed for a specific river, the more the river‘s ecol- ogy will change. The Lesotho Highlands Water Project 12 One of the world’s largest water resource develop- ments, the Lesotho Highlands Water Project will even- Authors tually comprise seven major dams on the headwaters Jacqueline King, Catherine Brown of the Senqu River system. Social and ecological con- cerns about the first dam built led to an environmen- Technical Adviser tal flow assessment for existing and planned parts of Stephen Lintner the development. Editor The Skagit River Hydroelectric Project 17 Robert Livernash An application to renew the operating license for hy- dropower dams on the Skagit River in the northwest- Production Staff ern United States created an opportunity to incorporate Cover Design: Cathe Fadel environmental flows into the license. Design and Production: The Word Express, Inc. The Murray-Darling Cap on Abstractions 20 Rivers of the Murray-Darling Basin in southeastern Aus- Notes tralia are seriously degraded as a result of over-ab- Unless otherwise stated, straction and increasing nutrient and salinity levels. A all dollars = U.S. dollars. “cap” on abstractions will limit further degradation until All tons are metric tons. flow assessments can be completed and environmen- tal flows implemented. The boundaries, colors, denominations, and any other information shown on any Widening Application of the Concept of maps do not imply, Environmental Flows 24 on the part of the World Bank Group, Environmental flow assessments also can be applied any judgment on the legal to wetlands, lakes, deltas, and inland seas. status of any territory, or any endorsement or acceptance of such boundaries. Conclusion 27 Water resources developments that alter the pattern Cover photo by of water movement in aquatic ecosystems need to J. Turpie be assessed for possible ecosystem effects. Waterbirds, Berg River floodplain, South Africa Further Information 28 3 WATER RESOURCES AND ENVIRONMENT • TECHNICAL NOTE C.2 Boxes 1. The main components of a river ecosystem 10 2. Phases of the Lesotho Highlands Water Project 12 3. Benefits and direct monetary costs of Phase 1 of the LHWP 13 4. Specialists involved in the Lesotho Flow Assessment 15 5. Predicted implications of four possible flow scenarios from Phase 1 and 2 dams in Lesotho 16 6. Costs of enhancement measures in the Settlement Agreement. 19 7. Examples of flow regulation protective measures for chinook salmon in the new license for operating the SRP 19 8. The Terror Lake Hydropower Project 20 9. The Central Valley Project, California, U.S.A.Box The Central Valley Project, California, U.S.A. 24 Figures 1. Environmental flow assessments in the decisionmaking process 11 2. The Lesotho Highlands Water Project 12 3. DRIFT Modules 15 4. The Murray-Darling Basin in Southeast Australia 21 5. Growth in water use in Murray-Darling Basin 22 4 ENVIRONMENTAL FLOWS: CASE STUDIES FOREWORD The environmentally sustainable development and priority in Bank lending. Many lessons have been management of water resources is a critical and learned, and these have contributed to changing complex issue for both rich and poor countries. It attitudes and practices in World Bank operations. is technically challenging and often entails difficult trade-offs among social, economic, and political con- Water resources management is also a critical de- siderations. Typically, the environment is treated velopment issue because of its many links to pov- as a marginal issue when it is actually key to sus- erty reduction, including health, agricultural tainable water management. productivity, industrial and energy development, and sustainable growth in downstream communi- According to the World Bank’s recently approved ties. But strategies to reduce poverty should not lead Water Resources Sector Strategy, “the environment to further degradation of water resources␣ or eco- is a special ‘water-using sector’ in that most envi- logical services. Finding a balance between these ronmental concerns are a central part of overall objectives is an important aspect of the Bank’s in- water resources management, and not just a part terest in sustainable development. The 2001 Envi- of a distinct water-using sector” (World Bank 2003: ronment Strategy underscores the linkages among 28). Being integral to overall water resources man- water resources management, environmental agement, the environment is “voiceless” when other sustainability, and poverty, and shows how the 2003 water using sectors have distinct voices. As a con- Water Resources Sector Strategy’s call for using sequence, representatives of these other water us- water as a vehicle for increasing growth and re- ing sectors need to be fully aware of the importance ducing poverty can be carried out in a socially and of environmental aspects of water resources man- environmentally responsible manner. agement for the development of their sectoral in- terests. Over the past few decades, many nations have been subjected to the ravages of either droughts or floods. For us in the World Bank, water resources man- Unsustainable land and water use practices have agement—including the development of surface and contributed to the degradation of the water resources groundwater resources for urban, rural, agriculture, base and are undermining the primary investments energy, mining, and industrial uses, as well as the in water supply, energy and irrigation infrastruc- protection of surface and groundwater sources, pol- ture, often also contributing to loss of biodiversity. lution control, watershed management, control of In response, new policy and institutional reforms water weeds, and restoration of degraded ecosys- are being developed to ensure responsible and sus- tems such as lakes and wetlands—is an important tainable practices are put in place, and new predic- element of our lending, supporting one of the es- tive and forecasting techniques are being developed sential building blocks for sustaining livelihoods and that can help to reduce the impacts and manage for social and economic development in general. the consequences of such events. The Environment Prior to 1993, environmental considerations of such and Water Resources Sector Strategies make it clear investments were addressed reactively and prima- that water must be treated as a resource that spans rily through the Bank’s safeguard policies. The 1993 multiple uses in a river basin, particularly to main- Water Resources Management Policy Paper broad- tain sufficient flows of sufficient quality at the ap- ened the development focus to include the protec- propriate times to offset upstream abstraction and tion and management of water resources in an pollution and sustain the downstream social, eco- environmentally sustainable, socially acceptable, logical, and hydrological functions of watersheds and economically efficient manner as an emerging and wetlands. 5 WATER RESOURCES AND ENVIRONMENT • TECHNICAL NOTE C.2 With the support of the Government of the Nether- The Notes are in eight categories: environmental lands, the Environment Department has prepared issues and lessons; institutional and regulatory is- an initial series of Water Resources and Environ- sues; environmental flow assessment; water qual- ment Technical Notes to improve the knowledge ity management; irrigation and drainage; water base about applying environmental management conservation (demand management); waterbody principles to water resources management. The management; and selected topics. The series may Technical Note series supports the implementation be expanded in the future to include other relevant of the World Bank 1993 Water Resources Manage- categories or topics. Not all topics will be of inter- ment Policy, 2001 Environment Strategy, and 2003 est to all specialists. Some will find the review of Water Resources Sector Strategy, as well as the past environmental practices in the water sector implementation of the Bank’s safeguard policies. useful for learning and improving their perfor- The Notes are also consistent with the Millennium mance; others may find their suggestions for fur- Development Goal objectives related to environmen- ther, more detailed information to be valuable; while tal sustainability of water resources. still others will find them useful as a reference on emerging topics such as environmental flow assess- The Notes are intended for use by those without ment, environmental regulations for private water specific training in water resources management utilities, inter-basin water transfers, and climate such as technical specialists, policymakers and variability and climate change. The latter topics are managers working on water sector related invest- likely to be of increasing importance as the World ments within the Bank; practitioners from bilateral, Bank implements its environment and water re- multilateral, and nongovernmental organizations; sources sector strategies and supports the next gen- and public and private sector specialists interested eration of water resources and environmental policy in environmentally sustainable water resources and institutional reforms. management. These people may have been trained as environmental, municipal, water resources, ir- rigation, power, or mining engineers; or as econo- mists, lawyers, sociologists, natural resources Kristalina Georgieva specialists, urban planners, environmental planners, Director or ecologists. Environment Department 6 ENVIRONMENTAL FLOWS: CASE STUDIES ACKNOWLEDGMENTS The Bank is deeply grateful to the Government of Lesotho; Hossein Sabet, S M EC International, the Netherlands for financing the production of this Lesotho; Mike Sale, Oak Ridge National Laboratory, Technical Note. USA; Dave Pflug and colleagues, Seattle City Light, USA; Bob Milhous and Lee Lamb, US Geological Technical Note C.2 was drafted by Jacqueline King Survey, USA; and Ben Dyer, Murray-Darling Basin and Catherine Brown of the Southern Waters Eco- Commission, Australia. logical Research and Consulting Pty (Ltd) in Cape Town, South Africa. At the World Bank, this Technical Note was reviewed by Hans-Olav Ibrekk, Alessandro Palmieri, Tor The authors thank the following specialists for their Ziegler, Jean-Roger Mercier, and Robert Robelus. assistance and advice: Makase Nyaphisi and Peter The editors appreciate their suggestions. Nuttall, Lesotho Highlands Development Authority, 7 ENVIRONMENTAL FLOWS: CASE STUDIES INTRODUCTION The flows of the world’s rivers are increasingly being decreasing turbidity–the focus in these notes is pri- modified through impoundments such as dams and marily on the direct effects of flow on the ecological weirs, extractions for agriculture and urban supply, functioning of rivers and the management of water maintenance of flows for navigation, inflows of drain- quantity. Note C.1 introduces concepts and methods age waters, and structures for flood control. These in- for determining environmental flow requirements terventions have had significant impacts, reducing the for rivers. Note C.2 reviews some important case his- total flow of many rivers and affecting both the sea- tories, which provide examples of the increasing sonality of flows and the size and frequency of floods. range of situations in which environmental flow as- In many cases, these modifications have adversely af- sessments are becoming a water-management tool, fected the ecological and hydrological services pro- and some of the legal, economic, social, and ecologi- vided by water ecosystems, which in turn has cal implications of pro-active flow management for increased the vulnerability of people–especially the river health. Note C.3 describes the reinstatement of poor–who depend on such services. It is increasingly flood releases from reservoirs for floodplain inunda- recognized that modifications to river flows need to be tion. Note C.4 addresses the downstream social is- balanced with maintenance of essential water-depen- sues arising from changes in flows. dent ecological services. The flows needed to main- tain these services are termed “environmental flows” Environmental flow assessments have evolved from and the process for determining such flows is termed the narrow purpose of describing flows for maintain- “environmental flow assessment” (EFA). ing specific fish species to their present use as a tool in holistic catchment management. The case studies The recognition that modifications to river flows are reflect this evolution. The first case study describes an important source of riverine, floodplain and, in how a flow assessment was completed in the plan- some cases, estuarine degradation is relatively re- ning stage of a water development to aid decisions on cent. The World Bank acknowledged the issue in its which dams should be built and how much water 1993 Water Resources Management Policy, which in- should be allocated to protecting the rivers and sub- cluded as an objective that “the water supply needs of sistence users dependent on those rivers. The second rivers, wetlands, and fisheries will be considered in case study illustrates how flows were set to mitigate decisions concerning the operation of reservoirs and impacts of an existing dam by modifying the down- the allocation of water.” An environmental assess- stream releases of water. Both describe advanced ment (Operational Policy 4.01) is triggered if modifi- forms of traditional environmental flow assessments. cations to river flows lead to adverse environmental The third case study describes another way that reha- risks and impacts. If changes in flow have the poten- bilitation of a seriously degraded river was initiated, tial to cause significant loss through placing a limit on or degradation of natural current levels of water ab- habitats, borrowers must straction. This does not con- comply with the Bank’s natu- stitute an environmental ral habitats policy (Opera- flow assessment itself, but Photo by Chilika Development Authority tional Policy 4.04) in order for provides breathing space for a loan to be approved. flow assessments to be pre- pared. Finally, the report Technical Notes C.1 to C.4 mentions three examples of deal with environmental how the concept of environ- flows. Although changes in mental flows is used in in- flow will affect water quality– creasingly broader ways in for example, by increasing or Fishtrap, Chilika Lake, India water management. 9 WATER RESOURCES AND ENVIRONMENT • TECHNICAL NOTE C.2 RIVER ECOSYSTEMS AND ENVIRONMENTAL FLOWS In this document, the term “river” is used to de- attributes appear. Often, the new attributes are less scribe the complete river ecosystem of many inter- welcome than the old; they could include, for dependent nonliving and living components. Rivers instance, pest flies, unreliable water supply, and are dynamic systems, sculptured by their flows, with algal blooms. The trend is one of increasing deg- dependence on different-sized flows at different radation. times of the year for the inundation of various chan- nel features and the completion of plant and ani- Many developed countries now regularly report on mal life cycles. Rivers respond to both natural river health, using classifications for river reach disturbances (such as drought) and man-made dis- conditions that are defined under national water turbances (such as dams) to flow; changes in the or enviromental policies and legislation. Each class components are shown in Box 1. In general, the summarizes a different level of degradation (such more the flows are changed for a specific river, the as A=near natural or pristine; B=slightly modified; more the river will change. C=moderately modified; D=largely modified; E=seriously modified; F=critically modified). A Man-made flow changes can be caused by direct number of developing countries are also adopting manipulation–such as damming or abstraction of their own classifications for river health. National water–or by activities in the surrounding catchment objectives may be to maintain a specified percent- that affect river flow, such as deforestation and land age of rivers in each category. use changes. The resulting changes to the river do not have to be left to chance, but can be predicted Technical Note C.1 provides more details on the re- and managed so that they stay within acceptable sponses of rivers to different flow events and op- limits. This is possible because rivers can be man- tions for managing flows. Information linking river aged to exist at different levels of condition. flow with environmental assessment is provided through an environmental flow assessment. In the Undisturbed rivers are generally seen as healthy context of a proposed water-related activity, the flow because their channels and species have evolved assessment is a means of describing the potential over long periods of time in harmony with their trade-offs between development gains—such as in- different environments, so that they process re- creased access to water for agriculture or indus- sources most efficiently. Their valued attributes trial use—and environmental losses—such as reduced include reliable, good-quality water supplies, flood- habitat for waterbirds or reductions in the quality plain fisheries, and stable banks. With increasing of life of subsistence users of the river. Environmen- disturbance, rivers lose valued attributes and new tal flows link water- or land-development objectives BOX 1. THE MAIN COMPONENTS OF A RIVER ECOSYSTEM Nonliving Living Channel, source to sea Riparian, fringing and aquatic plants Banks Fish, including marine fish that use estuaries Floodplains Aquatic invertebrates Linked lakes and wetlands Aquatic mammals Estuary Water birds Linked groundwater Amphibians and aquatic reptiles Linked near-coast marine environment Microorganisms Sediments Water chemistry and temperature 10 ENVIRONMENTAL FLOWS: CASE STUDIES with active management of river health. They are F IGURE 1. not just “flows for nature.” ENVIRONMENTAL FLOW ASSESSMENTS IN THE DECISIONMAKING PROCESS Scenarios showing these trade-offs should be as- sessed in terms of their wider macroeconomic im- Client selects scenarios plications—for example, for industry—and their that reflect a range of management options acceptability to all interested parties (Figure 1). Ultimately, society chooses which scenario is most acceptable, and in this way identifies a river’s de- For each scenario, the following are predicted: sired future condition. The flows described in the chosen scenario will maintain that desired condi- tion, and will become the environmental flow for • the impacts on river flow that river. They are unique to each river. • how this will change river condition • how the changing river condition will impact all users, including subsistence users • what the mitigation and compensation costs could be. Scenarios compared and assessed in terms of: • Macroeconomics • Stakeholder Acceptability (Public Participation Process) All Outputs to Decisionmakers 11 WATER RESOURCES AND ENVIRONMENT • TECHNICAL NOTE C.2 THE LESOTHO HIGHLANDS WATER PROJECT The Lesotho Highlands Water Project (LHWP)–one by rural communities, and the rivers flow through of the world’s largest water-resource developments– deep gorges that provide little opportunity for ur- will eventually comprise six major dams and a weir ban or agricultural development. on the headwaters of the Senqu River system. The project has been planned to be developed in 5 phases The river water was considered an important po- (Box 2). Phase 1A (Katse Dam) created social and tential source of revenue for this small developing ecological concerns that led (during phase 1B) to country, with South Africa’s Vaal Region as a po- an environmental flow assessment for all phase 1 tential recipient of the water. The Vaal Region is structures. The assessment produced scenarios of the industrial heart of South Africa, and vital to that how the downstream rivers would be affected by various dam release options, as well as the mitiga- tion and compensation costs for affected subsistence F IGURE 2. groups that use the river. THE LESOTHO HIGHLANDS To Vaal Dam WATER PROJECT Bethlehem BACKGROUND Delivery Tunnels 0 10 20 kilometers ORANGE Clarens F R E E S TAT E Masjaing N ATA L Lesotho is a landlocked country surrounded by Muela R. N go Butha- on e le d Buthe South Africa. The Senqu River system rises in the Ficksburg Hlotse Hl Ca (Leribe) ots PHASE II DR e AK Transfer EN eastern Highlands, becoming the Orange River as PHASE I Tunnel S B R. Transfer U R a ts o Tunnel it flows into South Africa (Figure 2). The Lesotho bam ku so at G M a li Teyateyaneng M Highlands are mountainous and characterized by PHASE I Interconnecting Matsoku Mokhotlong rainfall ranging from 700 to 1,500 mm annually. MASERU Tunnel u R. Katse Senq Dam Roma Mohale Dam Thaba Tseka Lin ak The powerful rivers that drain the region had vir- PHASE II Mashai en g Se nq un Dam tually natural flow until the 1990s, largely because ya ne R. Sehonghong TRANSKEI the Highlands are remote and sparsely inhabited Semonkong PHASE IV Ntoahae PHASE III Dam Tsoelike . Dam q uR Sen BOX 2. CAPE PROVINCE PHASES OF THE LESOTHO HIGHLANDS WATER PROJECT Phase Yield Facilities 1A I 18 m3 s-1 flow I 185 m Katse Dam on the Malibamatso River Completed 1998 I 72-MW hydropower I 55 m Muela Dam on the Nqoe River I Hydropower plant at Muela I Transmission lines to Maseru I Water delivery tunnels I Access roads and other infrastructure 1B I 9 m3 s-1 flow I 145 m Mohale Dam on the Senqunyane River Completed 2002 I 2 m3 s-1 flow I 20 m Matsoku Weir on the Matsoku River I Delivery tunnels to Katse Reservoir I Access roads and other infrastructure 2 Total estimated yield I Mashai Dam on the Senqu River and infrastructure 3 for all phases I Tsoelike Dam on the Senqu River and infrastructure 4 (1-5): 70 m3 s-1 flow I Ntoahae Dam on the Senqu River and infrastructure 5 I Malatsi Dam on the Senqunyane River and infrastructure 12 ENVIRONMENTAL FLOWS: CASE STUDIES country’s national economy. In the 1950s, with few rent government income for the next 50 years (Box natural water resources and increasing industrial 3). Development costs are borne mainly by South and urban demand, the Vaal Region was projected Africa. The LHWP creates jobs and, indirectly, many to be facing a water deficit—that is, a shortfall of other employment and development opportunities. supply compared to demand—of 106.7 m3 s-1 by 2023. Water stored in the scheme within Lesotho could Of the technically viable schemes to meet this short- lead to growth in agro-industry, forestry, fisheries, fall, the least expensive was the gravity-fed trans- and tourism endeavors. Another important benefit fer of water from the Lesotho Highlands. for Lesotho is the generation of electricity using the transfer water at Muela. Feasibility studies began in the 1950s, and in 1986 the LHWP got under way. The treaty between South Management of the LHWP. The Lesotho Highlands Africa and Lesotho signed in 1986 embraced five Water Commission (LHWC), which oversees the Phases (Box 2) in concept, but committed the coun- project, is a bi-national body answerable to both tries only to Phase 1. Although the scheme was con- governments, with monitoring, advisory, and ceived and begun during the apartheid era, the approval powers. Its main responsibility relates to current democratically elected governments of both project implementation in areas such as technical countries fully support the project, and the new acceptability, design of works, tender procedures Government of Namibia (through which the Orange and documents, cash flow forecasts, allocation of River flows to the ocean) has no objection. costs, and financing arrangements. A parastatal body in each country runs the LHWP: the Lesotho High- Benefits and costs. Both countries stand to benefit lands Development Authority (LHDA) in Lesotho from the scheme, essentially through South Africa and the Trans-Caledon Tunnel Authority (TCTA) securing a reliable annual supply of good-quality in South Africa. Identified stakeholders in the LHWP water, and Lesotho acquiring revenue that, from were represented on the steering committee guid- Phase 1 alone, amounts to about 14 percent of cur- ing the environmental flow assessment. BOX 3. BENEFITS AND DIRECT MONETARY COSTS OF PHASE 1 OF THE LHWP Lesotho South Africa Benefits: Benefits: I Annual revenue of $55 million from South Africa for 50 I Secures the cheapest substantial source of high- years quality water I No financial risk for water-transfer component I Lower water prices to consumers I Hydropower from Muela I Augmentation of water supply to newly enfranchised I Infrastucture such as roads and telecommunications poor to increase health, education, and trade services I Industrial growth in a water-scarce area of high I 39,000 person-years of direct employment for local economic importance. people I Additional enhancement of GDP through higher indirect employment, import duties, and tax receipts. Direct costs: Direct costs: I Hydropower component. I Full costs of construction, operation, and mainte- nance of the project except for the hydropower component I Associated debt I Annual royalties payment to Lesotho of $55 million I Compensation and mitigation costs I Social and development programs. 13 WATER RESOURCES AND ENVIRONMENT • TECHNICAL NOTE C.2 Existing and potential water conflicts. There were pacts of the dams, with a balance being sought be- two potential water conflict issues: (1) the popula- tween development of the river’s water resources tion at risk included about 39,000 subsistence us- and protection of river health. ers living along the targeted rivers and downstream of the dam sites; and (2) the scenic beauty of the ENVIRONMENTAL FLOW mountain regions and their rivers suggested a po- METHODOLOGY tential for ecotourism. Increasing the amount of river flow harnessed in The flow assessment study covering Phases 1 and dams increases direct revenue earned and the po- 2, commissioned by LHDA, began in 1997 and was tential for a range of development opportunities, but completed in 2000. It was designed to maximize also causes greater deterioration in the condition understanding of the rivers and human dependence of the rivers, which impacts both the population at upon them. Within a one-year data-collection pe- risk and ecotourism. A declining river condition riod, an international team of 27 scientists (Box 4) also would pose an increased threat to the rare collaborated to predict the changes in river con- and endangered Maloti minnow, Pseudobarbus dition that would occur if various dams were built quathlambae. and operated in specific ways, and the implications of these river changes for subsistence users. In 2001, The 1986 treaty stipulated that minimum compen- with changes in water use and demand in South sation flows of 0.5 m3 s-1 or higher should be re- Africa, it became clear that Phase 2 would not be leased from Katse Dam and 0.3 m3 s-1 or higher from imminent, and a new report was prepared to cover Mohale Dam, representing approximately 3 to 5 per- the environmental flow impacts of Phase 1 only. cent of the total annual flow of the rivers at those The Phase 1 EFA report was issued in July 2002. points. These lower limits, which were the target level LHDA was initially planning to use to operate Approach chosen. A holistic interactive approach— the system, would not support maintenance of the Downstream Response to Imposed Flow Transfor- downstream rivers in their historical condition. mations, or DRIFT—with four modules was developed for use in the study (Figure 3). In Module 1, the changes to the rivers were described in response FUTURE OPTIONS to flow changes. In Module 2, the population at risk was identified and their links to the rivers de- The 1986 treaty had a provision for renegotiating scribed (Box 5). In Module 3, four scenarios of interest the terms after 12 years, i.e. after 1998. The terms to the client were developed. Each predicted a pos- of the renegotiated treaty were delayed pending sible future flow regime; the resulting condition completion of a flow assessment and the resulting of the river; and the impacts on the Population at environmental flow requirement (EFR) policy, Risk (PAR). Module 4 dealt with mitigation and which will be used to optimize flow-release pat- compensation issues. terns from Katse Dam, Mohale Dam, and Matsoku Weir. The new treaty will also be used to help de- cide which other dams should be built, what the A pilot study of the population at risk measured the widths of inhabited corridors on either bank water-release patterns from these dams should be, what design features should be incorporated to fa- and identified the river resources used. A follow- cilitate environmental releases, and what mitiga- up study quantified resource use, estimated the costs of resources, and considered cultural links with tion and compensation measures need to be instituted to offset ecosystem and social impacts and the rivers. Medical and veterinary teams described costs. the health profiles of the population at risk and their domestic stock, and estimated the cost of Terms of the new treaty will be based partly on pre- measures to mitigate potential additional health dictions of the potential ecological and social im- risks. The information was used to describe the 14 ENVIRONMENTAL FLOWS: CASE STUDIES BOX 4. SPECIALISTS INVOLVED IN THE LESOTHO FLOW ASSESSMENT Biophysical Channel form Hydrologist, hydraulic modeler, sedimentologist, fluvial geomorphologist, physical-habitat specialist Water quality Aquatic chemist, microbiologist Biology Botanists for riparian, fringing and aquatic plants; zoologists for fish, invertebrates, frogs, reptiles, water birds, terrestrial wildlife Subsistence use Social Sociologist, anthropologist, public health doctor, animal health veterinarian, water-supply specialist Economic Economist, resource economist Process Flow-assessment facilitators Scenario builders F IGURE 3. links between the riparian people and the rivers, DRIFT MODULES and how flow changes might affect them. MODULE 1 MODULE 2 Biophysical Sociological The biophysical and socioeconomic specialists maintained strong links with each other during data Describe the nature Identify PAR collection. As an example, the botanists helped the and functioning of social team identify river plants used by the popu- the river Describe river use lation at risk, and then allocated each plant species and health profiles to one of six vegetation zones occurring up the Develop predictive banks. All the zones were then studied to define their capacity of flow links with flow. The hydrologist and hydraulic mod- related changes Develop predictive capacity of social eler linked each vegetation zone with flow by deter- impacts of river mining how often it is flooded under current flows. changes Knowing the links between flow and vegetation zones, the botanist could then describe for each pos- MODULE 3 sible future flow regime, how the vegetation zones Scenario development might expand or contract, and thus whether each Identify possible future plant species would increase or decrease in abun- scenarios and describe dance. The social team then used this prediction to biophysical consequences assess, for each scenario, the impact of vegetation of each changes on the population at risk. Describe social Because of the complexity of rivers, any study of this consequences of each MODULE 4 scenario nature—either in developing or developed countries– Economic is necessarily undertaken with only limited knowl- edge. In the Lesotho study, this uncertainty was Calculate compensation managed through the use of severity ratings, which and migration costs for PAR allowed scientists to indicate within a coarse range how great each described change would be (Sever- ity Rating 1 = negligible; Severity Rating 2 = Low; DRIFT output to Decisionmaker Severity Rating 3 = moderate; Severity Rating 4 = 15 WATER RESOURCES AND ENVIRONMENT • TECHNICAL NOTE C.2 Severe; Severity Rating 5 = Critically Severe). A spe- ers for subsistence. The process for deciding be- cialist might predict, for instance, that under a cer- tween these scenarios is expected to include three tain future scenario, fish species A would show a major stages: moderate reduction in abundance (Severity Rating I identifying the range of an acceptable volume 3). If there was uncertainty about which severity rat- of water for environmental maintenance ing to allocate to a predicted change, then a range I finding an optimum balance among flow re- of severity ratings was used–for example, fish spe- gime, economic and social costs, and envi- cies A would show moderate to critically severe re- ronmental impacts duction in abundance (Severity Rating 3-5). The final I making a formal commitment to environmental scenarios were thus illustrated as risk envelopes of flows in the form of an EFR policy. predicted changes, with wider envelopes indicating greater uncertainty. The EFA process and outcome has informed and improved project decisionmaking even though the MANAGEMENT IMPLICATIONS EFA was carried out during project implementation. The design of the Mohale Dam outlet structure was The scenarios in Box 5 illustrate that the more changed in 1998, ahead of the result of the flow as- water harnessed in the dams, the greater the impact sessment, in anticipation of the likely requirement on river health and on the people using the riv- for “greater-than-treaty” flows. The dam outlet works now incorporate a large release pipe as well as a multi-level release facility for smaller flows and a larger low-level facility for flood release. The EF releases from Matsoko Wier, which is not governed by the 1986 treaty, were increased from 0.05 m3 s-1 to 0.6 m3 s-1. The draft final EFR policy has recom- mended the following initial bulk EFRs from (a) Photo by Christian Boehm Katse Dam of 2.12 m3/s, which was increased from 0.5 m3/s and from (b) Mohale Dam of 1.01 m3/s, which was increased from 0.3 m3/s. These flows will be distributed as seasonal releases and as small Boy drinking from river, Lesotho floods. The EFR policy will also describe a specific BOX 5. PREDICTED IMPLICATIONS OF FOUR POSSIBLE FLOW SCENARIOS FROM PHASE 1 AND 2 DAMS IN LESOTHO Scenario Change in river condition Social impact of Costs of compensation Yield from present river change and mitigation of water Minimum change Low Negligible Low Very low Design limitation Moderate Moderate Moderate Low Treaty Critically Severe Severe Very High Medium Fourth Severe Moderately severe High Very High Minimum change = The maximum amount of water that could be removed by the dams before measurable change in river condition occurs. Design Limitation = Highest attainable river condition with current dam structures and moderate water-supply commitments. Treaty = Very low downstream releases from the dams as per the original treaty. Fourth = A fourth position in the range of possible scenarios, between Design Limitation and Treaty. 16 ENVIRONMENTAL FLOWS: CASE STUDIES mitigation and compensation program to offset the the first comprehensive assessment by the World impacts on communities and their resources. Bank in which downstream environmental analy- sis is explicitly linked to social analysis, and has The LHWP Environmental Flow Assessment rep- had significant influence on project decision- resents a major contribution to knowledge. It is making. THE SKAGIT RIVER HYDROELECTRIC PROJECT Hydropower dams on the Skagit River in the United After 15 years of studies, and 10 years of negotia- States provide electricity to the city of Seattle. An ap- tions, a comprehensive Settlement Agreement was plication to renew the operating license for the dams signed in 1991. The Federal Energy Regulatory Com- created an opportunity to incorporate environmen- mission (FERC) then issued a new 30-year operat- tal flows into the license to partially reverse past de- ing license to SCL in 1995. terioration to the river, and negotiate a settlement that maximized benefits for a range of stakeholders. BASIS OF THE ENVIRONMENTAL NEGOTIATIONS BACKGROUND FERC has exclusive authority in the United States The Skagit River rises in Canada and flows 162 miles to license nonfederal hydropower projects on navi- to its mouth in Puget Sound in the State of Washing- gable waterways and federal lands. FERC gave equal ton in the United States. About 70 percent of its drain- consideration to the need for power generation and age basin falls under U.S. federal administration, to issues related to energy conservation, fish and including 550 square miles of U.S. Forest Service wildlife resources, recreational opportunities, and wilderness, 750 square miles of national park, 170 other aspects of environmental quality. FERC square miles of national recreation area, and 60 identified four major resources that could be square miles in the National Wild and Scenic Rivers directly affected: System. I anadromous fish (species that migrate between sea and freshwaters) The Skagit River Project (SRP), which began opera- I sensitive terrestrial ecological resources tion in 1927, consists of three sequential hydropower I recreational and visual resources dams along the main stem of the river in the United I cultural resources. States: the Ross, Diablo, and Gorge Dams. It is the largest of six hydropower projects in the basin, with Additional indirect impacts to these resources could an installed capacity of 689 MW of power. occur through unstable slopes in reservoir draw- down areas, and continued transport of sediments The utility company for Seattle, Seattle City Light to downstream rivers, which would change the (SCL), holds the only water rights in the SRP, and nature of their channels. Only the combined water uses them only to generate hydropower. The origi- and fishery issues are addressed in this case study. nal operating license expired in 1977, and agencies and tribes concerned about fisheries and other en- The Skagit system is one of the few Puget Sound vironmental issues opposed re-licensing. As a re- basins in which salmon are managed on a natural- sult, operation of the SRP continued with annually stock basis. The fish are a major component of the renewed licenses, while intensive investigations and river ecosystem, an important fisheries resource, negotiations about re-licensing ensued among SCL; and attract one of the largest over-wintering popu- local, state, federal, and tribal governments; and en- lations of bald eagles in the United States. vironmental organizations. 17 WATER RESOURCES AND ENVIRONMENT • TECHNICAL NOTE C.2 The Skagit downstream of the lowest dam—Gorge provement of fish habitat and fish production. For Dam—receives migratory runs of all five species example, a 1968 license amendment required a of Pacific salmon and three other anad- minimum flow release from Gorge Dam, but within romous game species. Historically, the upper Skagit this constraint, releases still fluctuated with electric- River had abundant rainbow trout and other resi- ity demand. In 1978, through interim agreements, dent fish species, for which the dam reservoirs flow releases were modified to benefit downstream markedly increased habitat while reducing habi- fish, including reduced flow fluctuations and limi- tat for the flowing-water species. The rapid and large tations on the degree to which floods were con- fluctuations in releases from Gorge Dam also had trolled during the normal flood season. a major negative affect on the anadromous fish lower down the river. Low points in the fluctua- Other interim agreements addressed: tions severely reduced aquatic habitat, dried out I the impacts from fluctuating reservoir levels spawning grounds, left young fish stranded at wa- on fish spawning along shorelines and in tribu- ter edges and in potholes, and created shallow ar- taries eas through which adult fish could not migrate. I the loss of fish habitat through water being di- verted from the river through turbines FLOW AND FISHERIES RESEARCH I the maintenance of favorable water tempera- tures for fish. Research studies were undertaken on the impacts of the dam on the river. For example, a series of field These flow-management measures, carried out studies between 1979 and 1982 were designed to mostly during the 1980s, correlated with an in- determine the effects of flow fluctuations on the creased production of pink and chinook salmon. spawning behavior, egg deposition, incubation, hatching success, and tolerance to stranding of young steelhead trout and chinook and chum salmon. Sup- THE SETTLEMENT AGREEMENT porting laboratory studies focused mainly on deter- mining whether and under what conditions young The SA listed environmental enhancement mea- fish migrate into the riverbed to avoid being stranded. sures totaling about $100 million (Box 6). This in- Results indicated that more young fish survived if cluded a Fish Flow Plan that formalized the down-ramping (reduction) of dam releases occurred flow-management activities already in force and during daytime, and if the riverbed had coarse par- added other flow-related measures to enhance fish ticles with large interstitial spaces for them to move habitat (Box 7). It also included several measures into. These and many other findings led to interim not related to flow management—costing more than agreements on flow management, which were ne- $6 million—that would further reduce impacts of the gotiated without application of a specific flow- SRP on fishery resources. This component focused assessment method. A recommendation was made, on research and production programs and creation however, that the Instream Flow Incremental or improvement of critical fish habitat. Method (IFIM) (see Note C.1) be used to further guide flow management. REISSUE OF LICENSE THE INTERIM AGREEMENTS FERC concluded that the proposed SA struck a rea- sonable balance between the development values The interim agreements between the SCL and re- of the SRP and the values of the natural resources. source agencies, reached before and during the pe- Of the range of options considered, continued op- riod of annual licensing, later formed part of the eration under the terms of the SA was FERC’s pre- Settlement Agreement (SA). These mainly ad- ferred option. Cumulative effects would be no dressed flow requirements for protection and im- greater than under the present interim agreements, 18 ENVIRONMENTAL FLOWS: CASE STUDIES BOX 6. COSTS OF ENHANCEMENT MEASURES IN THE SETTLEMENT AGREEMENT. (ALL COSTS IN MILLIONS OF US DOLLARS AT 1990 VALUE AND MOSTLY SPREAD OVER THE 30-YEAR LICENSE PERIOD.) Category Examples of measures Cost (millions) Geology and Soils Erosion control at more than 50 sites 3 Fisheries I Interagency coordinating committees I Revised management of water levels in Ross reservoir I Flow management to protect spawning and juvenile habitat (Box 7): I flow plans for drought years I advance scheduling of hourly hydropower generation during each calendar day I Monitoring I Nonflow measures such as research and enhancement of fish habitat. 49 Vegetation and Acquisition and preservation of wildlife habitat 20 Wildlife Visual Resources I Revegetation I Redesign, relocation, or removal of several buildings 2.5 Cultural Resources Archaeological, historical, and architectural issues 6 Land-use and Enhanced recreational facilities 17 Recreation BOX 7. EXAMPLES OF FLOW REGULATION PROTECTIVE MEASURES FOR CHINOOK SALMON IN THE NEW LICENSE FOR OPERATING THE SRP. (CFS = CUBIC FEET OF WATER PER SECOND, FLOWING PAST A MEASURED POINT. DOWN-RAMPING = RATE OF CHANGE OF DECREASING POWER-PLANT WATER RELEASES) Protected feature Regulation Spawning period August 20 to October 15 Incubation period August 20 to April 30 Spawning flow During the spawning period, daily flows shall not exceed 4,500 cfs Incubation flows Minimum incubation flows each day of the incubation period as per a pre-agreed schedule. Protection of Fry The Salmon Fry Protection Period is February 1 to May 31. During this period, the City shall restrict down-ramping and adhere to minimum flows to protect fry. and in some cases would have new beneficial ef- tion. SCL received the 1998 Public Service Award fects on resources. With the new environmental from the Nature Conservancy of Washington for its protection measures in place, the SRP would con- environmental stewardship of the Skagit River ba- tinue to be economically viable and provide a sin, and is seen by many as a model for any public dependable and economic source of energy for agency seeking to combine energy production with its customers. protection of the natural environment. The Terror Lake Hydropower Project (Box 8) provides another The new license was a notable example of what example of how pre-licensing negotiations can pro- can be achieved through parties with different in- duce an atmosphere of cooperation and mutual terests being willing to negotiate a win-win solu- compromise, reducing conflict and costly delays. 19 WATER RESOURCES AND ENVIRONMENT • TECHNICAL NOTE C.2 BOX 8. THE TERROR LAKE HYDROPOWER PROJECT The Terror River, on Kodiak Island in Alaska, lies within the Kodiak National Wildlife Refuge. It supports commercially important runs of several species of Pacific Salmon. These fish are a vital food source for the Kodiak brown bear; the bear’s protection is the main purpose of the Refuge. The river is also a prime resource for generating hydropower. Between 1964 and 1981, negotiations took place be- tween the Kodiak Electric Association (KEA), which wished to establish a hydropower plant on the river to meet the entire electrical demand of the city of Kodiak, and a range of government institutions and other interested parties. The project became the first hydropower project for which a license was held up due to concern over environmental flows. KEA initially used a rule-of-thumb approach (The Tennant Method—see Technical Note C.1) to assess flows for fish mainte- nance. The licensing agency, FERC, felt this method was inappropriate outside its area of development, and also was too coarse to assess the impacts of a range of potential changes in flow. This led to a pioneering application of the Instream Flow Incremental Methodology (IFIM), which allowed the impacts of hydropower releases to be predicted and trade-offs to be considered. IFIM has two major features. First, it describes the changes in hydraulic conditions within the river with changing flows. Second, it evaluates these changing conditions in terms of suitable fish habitat. The IFIM assessment described how proposed flow changes could impact fish migration, salmon spawning, egg incubation, and rearing of juveniles. Because these activities took place at different times and required different kinds of flows, a key issue in the negotiations was the scheduling (timing) and volume of flow in the river at any time of the year. Major factors leading to a successful agreement were the early agreement to use IFIM, and the receptiveness of all interested parties to its outputs once they knew what the methodology could do and were regularly updated on emerging results. Using IFIM, minimum stream flows to be released from the project were specified, and the parties agreed to an Instream Flow Mitigation Plan. In June 1981, a compromise agreement incorporating these and other concerns was signed by KEA, the U.S. Department of the Interior, the State of Alaska, the Sierra Club, the National Audobon Society, and the National Wildlife Federation. FERC issued the license to proceed with the project in October 1981, which included specifications for monitoring the fisheries for 9 years. COMMENT inadequate refuge areas, all of which will affect fish numbers. There is a widespread belief, probably Fish are but one component of an interdependent underlying the Skagit River example, that if the flow ecosystem (Box 1). Although productive fisheries is appropriate for fish, it will probably serve most might be the objective, managing without consid- other ecosystem needs. In different projects this may eration for the other ecosystem components could or may not be so. Flow management is best ad- result in, for example, poor food supplies for the dressed for the whole ecosystem and not left fish, inappropriate water quality or temperature, or to chance. THE MURRAY-DARLING CAP ON ABSTRACTIONS The rivers of the Murray-Darling Basin in Austra- consideration of ecosystem functioning, but it lia are seriously degraded as a result of over-ab- represents an important policy decision to limit straction of water and increasing nutrient and further degradation of the river until flow assess- salinity levels. As a first move to halt river degra- ments can be completed and environmental dation, a limit (“cap”) has been placed on abstrac- flows implemented. tions. If this, along with other initiatives, does not achieve the desired level of river health, water al- BACKGROUND locations to offstream users may be reduced and re-allocated for river maintenance. The cap is not Located in southeastern Australia, the Murray- an environmental flow, because it is not based on Darling Basin covers one-seventh (1.06 x 106 km2) 20 ENVIRONMENTAL FLOWS: CASE STUDIES FIGURE 4. from the 1950s onwards, and at present the median THE MURRAY-DARLING BASIN IN SOUTHEAST AUSTRALIA annual flows from the basin to the sea are only 21 Queensland percent of those that occurred naturally. The lower Northern Territory Murray now experiences drought-like flows in more Charleville than 3-in-5 years, compared to 1-in-20 years under natural conditions. BRISBANE Toowoomba South Australia Projected growth in demand. Until 1995, the water Bourke New South Wales allocation system encouraged further development ar li ng R iv er of the water resources of the basin, rationing water D Dubbo Orange during droughts but not during normal or wet years. ADELAIDE Mildura SYDNEY A significant level of under-use of allocations still Mu rra y Riv er Murray Bridge CANBERRA existed. For example, in the period 1991-95, only Albury 63 percent of the permitted abstractions actually occurred. If all existing water entitlements were fully MELBOURNE used, the potential existed for long-term average ab- Victoria stractions from the whole basin to increase by a further 15 percent (Figure 5). This projected increase of the country’s total area (Figure 4). It encom- would have reduced the security of supply for ex- passes parts of four states—New South Wales, isting irrigators and exacerbated an already grave Victoria, South Australia, and Queensland—and the decline in river health. Australian Capital Territory (ACT). Some 2 mil- lion people live in the basin; another 1 million Existing and potential water conflicts. River-flow outside it are dependent on its water. It contains patterns have changed markedly, particularly in the some of the country’s best farmland, and use of lower reaches. The causes include flow regulation its waters has allowed expansion of irrigated ag- by dams and weir pools, and abstractions, primarily riculture into the drier inland areas. The value for irrigation areas. In certain seasons, far less flow of the basin’s agricultural produce exceeds Aus$8.5 than natural is available in these reaches to dilute billion per annum, of which Aus$3 billion is de- and carry away increasing volumes of nutrient-rich rived from irrigated land. Jobs created and for- agricultural runoff and urban wastewater. The con- eign income derived from the food-processing struction of weirs for irrigation off-takes has created industry further enhance the importance of this still, stratified conditions that promote the growth of area. The water is also used for domestic pur- blue-green algae, which sometimes increase to poses in Canberra, Adelaide, and many small problematic proportions as algal blooms. The algae country towns; for plantations, which account for can produce toxins that cause liver damage, stom- 15 percent of Australia’s income from forest prod- ach discomfort, skin and eye irritations, and disor- ucts; and for mining, which produces 6 percent ders of the nervous system. They can also cause of the country’s income from minerals. Hydro- livestock deaths, odorous and distasteful water, clog power produced at the Snowy Mountains Hydro- water-supply equipment and, when they decay, electric Scheme meets 5 percent of the region’s cause mass fish kills. The toxins can only be re- energy needs and diverts water across the catch- moved by advanced water purification systems. In ment divide into basin rivers. 1991, the world’s largest riverine bloom of blue- green algae developed along a 1,000-kilometer Development of the basin over the last 100 years stretch of the Darling River, causing the New South has resulted in increasing abstraction of water from Wales Government to declare a state of emergency. its rivers. Dams and weirs regulate about 80 per- cent of the approximately 17,500 kilometers of river Algal blooms are one very visible symptom of de- length. The rate of abstraction sharply increased clining river health. They occur because the natu- 21 WATER RESOURCES AND ENVIRONMENT • TECHNICAL NOTE C.2 ral checks and balances of a healthy river system F IGURE 5. have been lost. In the Murray-Darling, some of the GROWTH IN WATER USE IN MURRAY-DARLING BASIN imbalance has been caused by the loss of natural communities of aquatic plants and animals and their 14,000 Full development of existing Annual Diversion (GL/Year) replacement by introduced species, but arguably the Total entitlements 12,000 NSW major cause has been over-abstraction of water. Pre- Victoria S.A. dictions that these activities would continue to in- 10,000 Queensland ACT crease indicate that costly problems related to river Average Natural 8,000 Flow to Sea '88 '94 health could also be expected to increase in fre- quency and severity. 6,000 4,000 BALANCING CATCHMENT DEVELOPMENT 2,000 AND PROTECTION OF RIVER HEALTH 0 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 2020 The cap. The Murray-Darling Basin Ministerial Council is the highest-level forum for interstate Year cooperation on management of the basin’s natural resources. The council consists of relevant minis- ters from the five states and the national govern- ment. Being a political forum, the council has the sustainable use of the basin’s waters, the purpose power to recommend decisions for the basin as a of the cap was to restrain abstraction but not nec- whole. However, enactment remains the responsi- essarily development. New development would be bility of each state. In 1993, in response to growing allowed, provided the water was obtained by im- concern over water-use patterns, the Ministerial proving the efficiency of water use or by purchas- Council requested an audit of water use in the ba- ing water from existing developments (water trading sin. The audit indicated that the patterns of exist- for highest-value use). ing and projected water use were unsustainable. The council introduced the cap by unanimous vote, In 1995, in response to the audit, the Ministerial representing a consensus of government opinion Council introduced an interim cap on abstraction and policy across the basin. Impetus was provided of water from the basin for all consumptive uses. by the Council of Australian Governments, which Seen as an essential first step in achieving sus- in 1994 produced a Water Reform Agenda that tainable use of the rivers’ waters, this was con- inter alia redefined water rights and costs, and firmed as a permanent cap in 1997. The cap is stressed the need for water allocations for environ- presently defined as “The volume of water that mental maintenance. would have been diverted under 1993/94 levels of development. In unregulated rivers this Cap may Monitoring achievement. An Independent Audit be expressed as an end-of-valley flow regime.” The Group (IAG) advises on setting, implementing, and limit has no specific ecological significance, be- monitoring the cap. Abstractions are monitored in ing simply the level of abstractions two years be- each of the 23 major sub-catchments of the basin fore the cap was introduced. to determine if the cap is being achieved. The IAG annually reviews cap implementation, and reports The objective was to strike a balance between the to the chairman of the Ministerial Council. significant social and economic benefits of devel- oping the basin’s water resources, and the need for The methods used to determine whether usage in maintaining a healthy river system by safeguard- a sub-catchment has exceeded the cap have been ing adequate river flow. As an initial move toward modified with experience. The current rule is 22 ENVIRONMENTAL FLOWS: CASE STUDIES that if any sub-catchment in any year uses 20 per- contribute to deterioration of water quality and cent more water than its 1993-94 usage, corrected environmental protection for that year’s climate, then that area has breached I water allocations to be made with extreme sen- the cap. As an example, in the 1997-98 review of sitivity to the effects on the environment (Pre- cap implementation, the IAG found that the Barwon- cautionary Principle) Darling sub-catchment within New South Wales had I water to be allocated to the highest-value use breached the cap. Following discussion at the March I statutory and agreed property rights to be rec- 2000 Ministerial Council meeting, New South Wales ognized was requested to report to the August 2000 Minis- I water management processes to be transpar- terial Council meeting on the actions it is under- ent and auditable taking to bring abstractions in the Barwon-Darling I an administrative system that is easily under- within cap limits. stood and that minimizes time and costs. The current monitoring system addresses only volu- Equity issues that may jeopardize management of metric abstractions with no attention to river health, the cap fall into two categories: 1) pre-existing; a limitation recognized by the Ministerial Council. and 2) newly identified. Pre-existing equity issues The current cap may not allow sufficient water to included finalization of the cap limits for remain in the system to halt river degradation; as Queensland and ACT. If some jurisdictions were information about flow needs improves, the level exempt, the cap could be undermined. Newly iden- may have to be re-set. At the March 2000 Council tified equity issues include conflicts between ex- meeting, the Council requested that a sustainable isting users and new developers, and the inclusion rivers audit be prepared, with preliminary results of farm dams and tree plantations in the relevant on river health to be presented at the August 2000 caps. Overall, effective management of these is- meeting. sues requires a total catchment management ap- proach to water management that embraces the In October 2001, a pilot sustainable river audit was whole water cycle. approved to test the feasibility and effectiveness of audit options and procedures in four basins. The DEFINING THE ENVIRONMENTAL pilot audit is expected to report to the Council by FLOW REQUIREMENT mid-2003. With the cap in place, the focus now is on ensur- STAKEHOLDER AND EQUITY ISSUES ing the health of the rivers. The starting point is the assessment of river health that will be provided Implementation of the cap was a policy decision by the year 2000 Sustainable Rivers Audit. But taken by all relevant governments. As such, the key beyond this, there is no basin-wide move to take policy stakeholders were the next step of defining involved, and they in turn and reserving environ- worked with their constitu- mental flows for all the riv- encies. ers. Such flow assessments are being done for many Photo by Willem van Aken, ©CSIRO From the outset, equity was sub-catchments (includ- an important implementa- ing by expert panels of tion issue. The IAG devel- river specialists—see Note oped six principles to assess C.1), but these are not equity: being integrated to deliver I no further change to environmental flows to flow regimes that would River Red Gums,Murray River, Australia maintain all the basin’s 23 WATER RESOURCES AND ENVIRONMENT • TECHNICAL NOTE C.2 rivers—including the Murray and Darling Rivers— A further difficulty is likely to arise. The cap allows in a healthy condition. for irrigation development through improvements in water use efficiency as long as the water extracted There is growing recognition that this next step from the river remains within the cap. These effi- should be taken. However, any change in river man- ciency improvements will come partly from reduced agement that requires more river flow for the envi- leakage in distribution systems and on-farm. The ronment would imply a reduction somewhere else, consequence is that surface and subsurface return and this would be difficult politically. Nevertheless, flows to the rivers of the Basin will decrease. Thus, the process is gradually gaining momentum, follow- the cap could have the perverse effect of decreas- ing precedents in other countries where historical ing river flows and placing greater pressure on the water allocations have led to severe environmental aquatic environment. problems (Box 9). WIDENING APPLICATION OF THE CONCEPT OF ENVIRONMENTAL FLOWS The impact of flow manipulations is not reflected THE CARONI SWAMP OF TRINIDAD only in river channels. Wetlands, lakes, deltas, AND TOBAGO groundwater reserves and inland seas are all becom- ing degraded due to disturbance of their natural pat- The Caroni Swamp is the country’s largest man- terns of water movement. This section provides three grove swamp, supporting 157 bird species, includ- examples—the Caroni Swamp in Trinidad and Tobago, ing migratory waterfowl and the national bird, the the Lower Mekong River, and the Aral Sea—of prob- scarlet ibis. Over the last few decades, various ab- lems that have emerged, and the moves to limit or stractions and other catchment activities have reverse degradation of both the water bodies and the sharply reduced the freshwater inflows from quality of life of the riparian peoples. groundwater, overland flow, and its four rivers. In BOX 9. THE CENTRAL VALLEY PROJECT, CALIFORNIA, U.S.A. In 1937, the Central Valley Project (CVP) was launched to divert water from the Sacramento-San Joaquin River delta to southern California. This was supplemented in 1960 by the State Water Project, with the two schemes providing 10 million acre-feet of water to southern California and enhancing the welfare of rural areas and industrial growth. How- ever, there were massive ecological impacts, including a serious decline of sport and commercial fisheries, loss of 95 percent of the state’s wetlands, decline of migratory bird and waterfowl populations from 60 million to 3 million, and enhanced salinity levels in the donor systems. Policies and laws to mitigate this include the CVP Improvement Act of 1992, which placed environmental restoration and protection on an equal footing with offstream water demands. Operation of CVP facilities is changing to allow re- allocation of an additional 800,000 acre-feet of water yield from offstream users to the environment. An $80 million temperature control device was added to Shasta Dam to aid Sacramento River salmon, and more than $100 million has been spent on environmental rehabilitation. By 1997, debate over major sections of the act continued, including management of the environmental water alloca- tion and the Anadromous Fish Restoration Program. There was dispute over the definition of yield and where it should be measured; whether downstream flows could be re-captured and exported; and how and where the water could best be used for the environment. The amount of water needed at the delta to double fish populations was questioned, as was the adequacy of the underlying science. Renewed contracts for water allocations now cost more and require water conservation plans and payment into a restoration fund. 24 ENVIRONMENTAL FLOWS: CASE STUDIES addition, pollution from various industries and rum The Great Lake, or Tonle Sap, is of exceptional eco- processing plants have increased waste discharges logical, economic, and cultural importance. Situ- into the Caroni River. Flood protection works, em- ated in Cambodia, it is linked to the Mekong River bankments, and canals have prevented floodplains by the Tonle Sap River. In the dry season, the Great from being inundated and allowed increased inflow Lake drains into the Mekong. In the wet season, of marine waters. Increasing salinization and loss the Mekong reverses the flow of the Tonle Sap River, of a range of habitats has resulted in an overall de- which expands the lake from about 3,000 km2 to cline in biodiversity and a falling abundance of 16,000 km2. Gradual drainage of the lake in the dry plants and animals, including the scarlet ibis. season significantly contributes to dry-season low flows in the delta. The annual fish catch of the The World Bank-supported Trinidad and Tobago lower Mekong, some 1.5-2.0 million tons, is largely Water Resources Management Strategy recom- dependent on the annual flooding and draining of mended measures for the rehabilitation of the the Tonle Sap. swamp, including increasing freshwater and sedi- ment inflows, retarding drainage of water from the In 2000, the Mekong River Commission (MRC), swamp, excluding seawater intrusion, and control- which is charged with implementing the Mekong ling point and nonpoint sources of pollution. Two Agreement, received $10.8 million from the Global critical considerations will be 1) restoring flushing Environment Facility to develop “Rules for Water floods and not just increasing base flows; and 2) Utilization,” including rules for cooperation in the ensuring the extra water is of high quality, brought maintenance of flows in the main stream. Article 6 from high in the catchment. A further consideration of the agreement requires that the following flows is that all remedial work should be simple and not be adhered to, except in years of historically severe require highly skilled professionals to maintain it. droughts or floods: The ultimate aim is to reverse the decline in I not less than the acceptable minimum monthly biodiversity and ensure sustainable use of the natural flow during each month of the dry sea- swamp’s valued ecological attributes. son I the natural reversal of flows into the Tonle Sap in THE LOWER MEKONG RIVER the wet season I average daily peak flows that are not greater than would naturally occur on average during the In 1995, the four riparian countries of the lower flood season. Mekong—Cambodia, Laos, Thailand, and Vietnam— signed an “Agreement on Co-operation for the Sus- Agreed flows will be based on a process of tainable Development of the Mekong River Basin.” transboundary analysis, which began in 2000. Mini- Although all parts of the system will be addressed, mum flows for the dry season are due to be set by two critical areas will receive special attention. 2004. The World Bank is providing technical assis- These are the delta in Vietnam and the Tonle Sap tance for the determination of environmental flow Lake in Cambodia. The delta covers about 12 per- requirements for the Mekong River Basin. cent of Vietnam’s land area, supports about 17 mil- lion people, and produces half of the country’s rice. With catchment and other changes, the river’s flow THE ARAL SEA is becoming increasingly subject to floods, with “ex- cessive” floods occurring about every 30 years in- Until the 1960s, the Aral Sea was the fourth largest stead of every 200 years, and consequent lower flow inland body of freshwater in the world, and was in the dry season. As a result, there is increasing vital to life in the Central Asian states of Tajikistan, saltwater intrusion into the delta, which adversely Kyrgyz Republic, Uzbekistan, Kazakhstan, and affects delta residents, domestic water supplies, and Turkmenistan. Irrigated agriculture has been prac- up to 2 million hectares of agricultural land. ticed for thousands of years in the Aral Basin and 25 WATER RESOURCES AND ENVIRONMENT • TECHNICAL NOTE C.2 currently supports 40 million people. Irrigation, It is probably economically, socially, and ecologi- mostly of rice and cotton, has been both the means cally impossible to restore the Aral Sea to its origi- of survival for the people, and the main cause of nal condition. A new balance needs to be struck the decline of the Basin’s water resources. The to maintain the water bodies at agreed levels of irrigated area has more than tripled in the last health that will also address the needs of millions hundred years, to the present 8 million hectares. of poor people. This is being addressed through ef- To support this, more than 90 percent of the river forts of the Global Environment Facility, the World flow into the Aral Sea has been diverted, and its Bank, and many other multilateral, bilateral, and present volume is 70 percent less than histori- national organizations. Efforts will focus on two cal levels. The remaining lake has split into a main objectives. First, the irrigation infrastructure smaller northern section, with some inflow re- will be rehabilitated to increase its efficiency. Sec- maining, and a larger southern portion that is ond, the northern Aral Sea will be isolated and, hypersaline and mostly biologically dead. Increas- through managed environmental flows, an attempt ing salinization is also a major problem in the will be made to restore some of its original ecosys- surrounding irrigated land. tem attributes. 26 ENVIRONMENTAL FLOWS: CASE STUDIES CONCLUSION There is growing awareness that catchment and I Use of best available knowledge from these pro- water resource developments that alter the pattern grams, together with directed short-term re- of water movement in aquatic ecosystems will cause search, to answer management questions the systems to change. These changes do not have (moving ahead with limited knowledge) to be left to chance, but can be anticipated and lim- I Use of structured, transparent processes for ited to a level that society finds acceptable. Many options assessment and decisionmaking that techniques have evolved for environmental flow equally address economic, ecological, social, assessments (see Note C.1). As the examples de- and engineering concerns (assessing the full im- scribed here reveal, these techniques can be used plications of all options and negotiating in different ways to provide advice on development tradeoffs) options . World Bank experience in EFA is evolving I Monitoring the outcome of the chosen option slowly. (learning by doing) I Adjustment of management plans where indi- The availability of these flow assessment techniques cated by monitoring results (employing strate- is a step forward, but in isolation can achieve little. gic adaptive management). All too commonly, and irrespective of the chosen method, there are few relevant data, limited funds, To achieve this strategy, five factors for success few specialists with relevant skills and experience, are apparent in the case studies. First, down- poor understanding of the targeted aquatic system, stream communities have an important role to play and development needs that are so urgent that de- in the decisionmaking process, which is likely to cisions cannot wait until all of the preceding are impact and alter there livelihoods. Second, the wa- fully resolved. ter authorities need to move from being provid- ers of water to becoming holistic managers of If responsible environmental management, and the water resources. Third, scientists and manag- concept of sustainable use, are to succeed, scien- ers need to agree to work together in an envi- tific advisors, water managers, and decisionmakers ronment of limited knowledge. Fourth, emerging could benefit from a working relationship based on legislation on sustainable resource use, either a six-point strategy: from within the country or from outside, needs I Development of appropriate policy and legisla- to be implemented to provide impetus for and tion on resource protection (legitimizing sus- legitimacy to the environmental flow assess- tainable use) ments. Fifth, the move toward sustainable river I Directed national programs of research on the use, though difficult, is typified by negotiation, links between ecosystems and flow (increasing transparent decision making, and attention to the knowledge base) equity and conservation issues. 27 WATER RESOURCES AND ENVIRONMENT • TECHNICAL NOTE C.2 FURTHER READING Lesotho Highlands ommendations from the Terror Lake project.” Washington, D.C.: U.S. Fish and Wildlife Service. Boadu, F.O. 1998. “Relational characteristics of FWS/OBS-84/08. transboundary water treaties: Lesotho’s water Bovee, K.D. 1982. “A guide to stream habitat analysis us- transfer Treaty with the Republic of South Af- ing the Instream Flow Incremental Methodology.” rica.” Natural Resources Journal 38:381-409. Instream Flow Information Paper 12. Washing- Lesotho Highlands Development Authority (LHDA). Un- ton, D.C.: U.S. Fish and Wildlife Service. FWS/ dated. “Environmental and social aspects of the OBS-82/26. Lesotho Highlands Water Project.” Maseru, Lesotho: LHDA. Web site: www.lhwp.org.ls Murray-Darling Basin Blackmore, D.J. 1999. “The Murray-Darling Basin Cap Skagit River on diversions – policy and practice for the new millennium.” Address at National Water Sympo- Stober, Q.J., S.C. Crumley, D.E. Fast, E.S. Killebrew, R.M. sium, Sydney, Australia. Woodin, G. Engman, and G. Tutmark. 1982. “Ef- Murray-Darling Basin Commission. 1999. “Review of Cap fects of hydroelectric discharge fluctuations on implementation 1998/99: Report of the Indepen- salmon and steelhead in the Skagit River, Wash- dent Audit Group.” Canberra, Australia: Murray- ington: Final Report from the Washington De- Darling Basin Commission. partments of Fisheries and Game to the City of Chenoweth, J.L., and H.M. Malano. 2001. “Decision mak- Seattle.” ing in multi-jurisdictional river basins: A case Federal Energy Regulatory Commission. 1996. “Environ- study of the Murray-Darling Basin.” Water Inter- mental assessment for new hydropower license: national 26(3): 301-313. Skagit River Hydroelectric project.” Washington, Web site: www.mdbc.gov.au D.C.: Federal Energy Regulatory Commission. FERC Project No. 553. Web site: http://www.ci.seattle.wa.us The Central Valley Project McCarthy E. 1997. “CVP Improvement Act update.” West- Terror River ern Water: 4-13. Olive, S.W. and B.L. Lamb. 1984. “Conducting a FERC environmental assessment: a case study and rec- 28