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Science, Management and Conservation
<br />FLOW REGULATION AND RIVER ECOSYSTEM RESTORATION. Louis A. Toth, William A.
<br />Perkins, Jayantha T.B. Obeysekera, and M. Kent Loftin. South Florida Water
<br />Management District, P.O. Box 24680, West Palm Beach, FL. 33416-4680.
<br />Between 1984-89, a Demonstration Project was conducted to evaluate the feasibility of using
<br />dechannelization to restore environmental values of the Kissimmee River, a subtropical river
<br />in central Florida. The principle components of this project were diversion of flow through
<br />remnant river channels, and reflooding of drained floodplain. Monitoring data showed that
<br />these measures led to positive changes in both structural and functional aspects of river
<br />and floodplain ecology. However, results also indicated that more complete restoration of
<br />biological attributes will require reestablishment of more natural river/floodplain
<br />hydrology. Due to flood control regulation schedules of its headwater lakes, current river
<br />discharge regimes are pulse-like, include extended periods of no flow, and have high and
<br />low flow periods which are out of phase, compared to typical seasonal patterns that occurred
<br />prior to channelization. During the Demonstration Project, these unnatural flow character-
<br />istics contributed to fish kills and chronic low dissolved oxygen levels, interfered with
<br />fish reproduction, and limited floodplain inundation. Simulation modelling was used to
<br />develop a mwdified headwater lake regulation schedule, which reestablishes seasonal flow
<br />patterns, smooths discharge peaks, and maintains base flows for a greater portion of the
<br />year. Modelling results indicate that implementation of the new schedule, and extensive
<br />canal backfilling, will lead to discharge and stage characteristics that meet established
<br />criteria for achieving ecosystem restoration goals. This restoration plan is expected to
<br />restore the ecological integrity of 9000 ha of river/floodplain ecosystem.
<br />RESERVOIR SEDIMENTATION: CONSERVATION ALTERNATIVES IN
<br />MANAGING PERTURBED WATERSHEDS AND IMPLICATIONS TO FISH AND
<br />FISH-FOOD ORGANISMS. Merlyn Brusven, Division of Entomology, and David Walker,
<br />Department of Agricultural Economics, University of Idaho, Moscow, Idaho 83843.
<br />Sediment originating from agricultural lands is the primary nonpoint source pollutant from private lands in
<br />North America. The Columbia and Snake Rivers of Oregon, Washington and Idaho are highly regulated
<br />by numerous dams. Effective reservoir life of these dams is finite since they are destined to fill with
<br />sediments. Lower Granite Dam and Reservoir on the upper Snake River in Washington has a projected
<br />effective storage life of approximately 100 yeazs. Alternative conservation practices In upstream
<br />watersheds can be used to reduce sedimentation, hence, extend the life of the reservoir. A systems
<br />approach is advocated to integrate resource components so that managers can balance ecological and
<br />economic pazameters in order to trLnimi~e offsite sediment impacts in downstream reservoirs. Conceptual
<br />models that link land-use practices with water quality and the ecology of receiving waters will be
<br />presented. Additionally, an integrated planningg methodology, currently being developed and tested in a
<br />dryland farming region In northern Idaho, will be discussed. The methodology integrates soil, ecolog~'cal,
<br />hydrological and economic variables in the resource management planning process using a Geographic
<br />Information System (GIS).
<br />Conservation-based Management: from theory to practice in River Murray Valley wetlands
<br />Anne Jensen, formerly Senior Officer, Murray Valley Management, Department of Environment
<br />and Planning; currently Regional Manager Outback, South Australian Department of Lands, GPO
<br />Box 2370, Adelaide, SOUTH AUSTRALIA 5001.
<br />A major stumbling block in modem natural resource management is a lack of precise saentific knowledge of the system
<br />to be managed. In most cases, the original ecosystem was significantly changed before any scientific analysis was undertaken,
<br />and even where studies have been conducted, they are often limited by resources, funding and time in providing the detailed
<br />answers scientists would like to have before embarking on practical management measures to conserve the system.
<br />As a result, science-based managers often have to start managing without rigorous information on which to base
<br />management decisions. The use of field trials can be a useful tool in these situations. Where saence can give a general
<br />direction, field trials can quickly establish the value of that direction in practice. It is often critical to make a stand
<br />alongside the engineers, even though knowledge is limited, in order to have any influence on the outcome and to achieve
<br />any measure of conservation.
<br />Along the River Murray Valley in South Australia, field trials in wetland management are underway, based on scientific
<br />principles derived from available literature and basic inventory data. A series of wetlands have been selected for speafic
<br />management works to improve habitat value. The results will add to scientific understanding of these systems.
<br />Techniques for management of these wetland systems for conservation purposes are being refined and winning acceptance
<br />with engineers and planners. Limited scientific knowledge is successfully being turned into practical management techniques
<br />which allow conservation goals to be met alongside other river management goals. This approach has helped to overcome
<br />the lack of specific krnowledge while still meeting management deadlines and having a say in the way the system is being
<br />managed.
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