Instream flow protection and restoration: setting a new compass point.

• Author: Mathews, Ruth
• Position: Western Instream Flows: Fifty Years of Progress and Setbacks

1. INTRODUCTION A. Water for Instream Values B. Out-of-Stream Uses C. Legal Protection for Instream Flows II. SURVEY OF STATE INSTREAM FLOW PROGRAMS A. Survey B. Survey Results 1. Capacity 2. Legal and Regulatory Framework 3. Public and Legislature Awareness 4. Science and Technical Tools 5. Monitoring and Enforcement 6. What Most Needs to Be Changed 7. How Will this Change Occur III. THE NEXT FIFTY YEARS I. INTRODUCTION

   Rivers, lakes, and aquifers are the source of freshwater for human needs from drinking water to irrigation for industrial uses, and for many other uses. They also provide water for a wide range of species, including fish and other aquatic plants and animals that live in river, estuarine, groundwater, lake, and wetland ecosystems; terrestrial plants and animals that inhabit floodplain and riparian ecosystems; and the many animals that move to and from these areas during their fives. These freshwater-dependent ecosystems, which support a rich biodiversity with many complex interactions and interdependencies among species, can be hydrologically connected, thereby linking the rise and fall of river flows, lake, and aquifer levels. As humans utilize water, either withdrawing it from rivers, lakes, and aquifers or manipulating the flow regime in rivers, water is no longer available to native species in the manner to which they have adapted. An instream flow, or environmental flow as it is commonly referred to in many countries, is the quantity of water allocated to remain in a river to conserve the biodiversity dependent upon these diverse and interconnected ecosystems.

   At this fifty-year mark commemorating Oregon's 1955 Act establishing the State Water Resources Board, (1) a historic step toward legal protection for instream flows in the West, it is important to step back and take stock of the progress that has been made to date toward securing water in rivers for river-dependent biodiversity and the ecosystems this biodiversity inhabits. In the fall of 2005, The Nature Conservancy (TNC) commissioned a survey of state instream flow programs to assess the status of these programs and identify, if possible, key strategies for making them more successful and effective in protecting and restoring instream flows. (2) Since the advent of legal protection for instream flows, varying amounts of public and private resources have been dedicated to setting, securing, and enforcing instream flows in each state, and each state has developed its own legal and institutional history of instream flow protection and restoration. While each state has a unique context within which instream flow protection and restoration occurs due to the particulars of the legal, institutional, geographical, cultural, and economic histories, and the current political climate, broad themes were expressed repeatedly throughout the interviews. While TNC will use this information to guide its own involvement in instream flow protection and restoration activities, it is offered here to provide the larger community, already actively involved in instream flow issues or considering involvement, with a useful assessment of state instream flow programs. As we compare where we are today to where we need to be in protecting and restoring instream flows, we can see that ensuring the long-term maintenance of healthy river, floodplain, and estuarine ecosystems, and the native species they support, will be a mammoth task. We can also discern the focal areas in which to direct the limited resources available for this work.

   1. Water for Instream Values

      When evaluating the efficacy of instream flow policy implementation, advancements in the scientific understanding of the role river flows play in maintaining the health of river, floodplain, and estuarine ecosystems must be considered. The species that depend upon these ecosystems for their survival have, over millennia, evolved in response to the full range of flows--low flows, high flows, and floods--and their intraannual and interannual variability. (3) Each species has developed life history traits that take advantage of specific flow levels, as well as the timing, duration, frequency, and rate of change of these flow levels) With critical aspects of their survival such as reproduction, feeding, and movement between habitats closely tied to the long-term historical patterns of dynamic variation in flows, maintaining the natural range of variation of the flow regime is necessary to sustain the rich diversity of species found in river, floodplain, and estuarine ecosystems. (5) Reaching far beyond the common practice of establishing a minimum flow level for a single species or even a particular life history trait of that species, river scientists have firmly established that naturally varying river flows are central to ecosystem health and species survival. (6)

      Traditionally thought of as minimum flows, instream flows have primarily maintained a level of flow below which a river will not go. This flow quantity can be considered a critical low flow that provides species protection during periods of drought or high water use. At these times of extreme low flow, instream flows can provide species an essential buffer between life and death. However, instream flows that solely protect the minimum or extreme low flow fall short of the level necessary to ensure the long-term viability of these ecosystems. Furthermore, providing a single flow level for an individual species or a specific life history trait is not sufficient. For ecosystem maintenance and biodiversity conservation, instream flow levels that minimize the departure from all components of the natural flow regime--low flows, high flows, and floods--are the goal. (7)

      In addition to biodiversity conservation, flows that sustain healthy river, floodplain, and estuarine ecosystems provide a wide range of ecosystem services that benefit people. These benefits include: provision of water supplies, provision of food, water purification and treatment, flood mitigation, provision of habitat, soil fertility maintenance, nutrient delivery, maintenance of coastal salinity zones, provision of beauty and life-fulfilling values, and recreational opportunities. (8) Often invisible, ecosystem services and their value to society are frequently ignored when determining the allocation of water to instream flows. If included, ecosystem services would further underline the importance of dedicating water to instream flows beyond just the minimum flow. Degradation of river, floodplain, and estuarine ecosystems through alteration of the flow regime results in lost opportunities for individuals and society, opportunities inherent in healthy ecosystems. Therefore, ecosystem services must be considered in the determination of instream flows ff society is going to have access to the full benefits available from these ecosystems.

   2. Out-of-Stream Uses

      Water use, whether in the water scarce regions of the arid West or in the relatively water rich areas in other parts of the country, has historically developed to serve human purposes that remove water from a river or otherwise alter its flow. Water is diverted or extracted from rivers, lakes, or underground aquifers for a wide variety of purposes, including mining, irrigation, and stock watering, as well as for industrial, municipal, or individual water supply. River flows and lake levels are manipulated for water storage, navigation, flood control, and hydroelectric power generation. Beyond these direct water uses, a variety of other human activities can also alter the flow regime of rivers. For example, building levees to protect low-lying areas from flooding, installing rip rap to stabilize shorelines, and removing native vegetation from riparian and floodplain areas can change river flow dynamics. Conversion of upland areas of watersheds from their natural land cover by human activities, such as logging, mining, or agriculture, or to provide space for human populations and their associated infrastructure, can also fundamentally change the flow regime of a river.

   3. Legal Protection for Instream Flows

      The historical bias toward water and land uses that manipulate the natural environment is represented in the legal protections afforded these uses in both the prior appropriation water rights system of the West and the riparian system of water permitting. Both of these systems, and their hybrid forms developed in some states, initially excluded protections for water remaining in a river for ecosystem needs and did not consider the allocation of water for the provision of ecosystem services as a beneficial use. As river flows have been altered by these out-of-stream or flow-altering water uses, however, there have been significant levels of degradation of river, floodplain, and estuarine ecosystems followed by the attendant loss or diminishment of native species. (9) Recognizing these losses led states across the country to pass laws affording legal protection for instream flows. These state laws ensure varying degrees of legal protection for instream flows.

      Legal protection for instream flows occurs at different points along the continuum of water use from pristine rivers with no flow-altering water uses to hilly, or even over, appropriated river reaches or basins. For example, high elevation tributary rivers on public lands may have no historical water use, while in much of the arid West rivers were already over allocated decades before instream flow laws were passed. Application of instream flow laws thus results in two forms of instream flow activity: protection and restoration. Instream flow protection occurs when there has not been substantial flow alteration through human activities, and the goal is to maintain a healthy river, floodplain, or estuarine ecosystem, or all three. Thus, instream flow protection legally secures the necessary river flows and protects rivers from future water uses impinging upon these...