Development and Use of Fisheries Models in Water Resource Planning: Assessing Impacts of Alternative Operations
* Can fisheries based models be developed and used by Reclamation to evaluate the biological merits of alternative river operations while simultaneously considering the impacts to irrigation and power delivery?
Need and Benefit
Fisheries based models can be used as tools to help water managers evaluate impacts of hypothetical changes in river operations. This proposal outlines the development of potential uses of two models in the Yakima River basin, Washington. Research will focus on the efficacy of using models for evaluating impacts of hydrologic regime changes especially those most critical to fisheries production. Ultimately, models will be used to identify and test which flow regimes have the greatest potential to:
* Avoid federal listing of any further fishes
* Meet life history requirements of native fish species
* Contribute to the delisting of threatened and endangered fishes.
In the Yakima River, we are developing modeling techniques to address each of these three needs. Simultaneously, using RiverWare, we'll track and evaluate impacts to irrigation, power, and other users.
The first of these modeling needs is to identify reaches and flow regimes that have the greatest chance of ecosystem recovery. In so doing, we provide water managers with information that they require to make decisions that may result in avoidance of future listing of fish. To accomplish this, the modeling approach we have deployed is called Range of Variability Analysis (RVA) (Richter, et al. 1997). We developed RVA in the Yakima River. RVA identified components of the discharge regime that had been altered by the irrigation project or other human development. We have begun deployment by supplying RVA results to the Systems Operation Advisory Committee (SOAC). SOAC is responsible for advising Reclamation on fish issues related to the Yakima Project. SOAC has communicated to Reclamation that they intend to use RVA as a means of assessing impacts of various dam release targets.
The second need for modeling is to identify and evaluate how different flow regimes can potentially meet life history requirements of fishes. To accomplish this, the modeling approach we will employ is called Ecosystem Diagnosis and Treatment (EDT) (Mobrand and Associates, http://www.mobrand.com/edt.html). We propose to apply EDT at selected locations within the Yakima River basin. EDT will help determine how life history requirements of fishes can be met and to predict anadromous salmonid production over a range of alternative river operations. These predictions can determine which range of alternatives may be the most beneficial for improving salmonid production if that flow regime were implemented.
The third need is to contribute to the delisting of threatened and endangered fish. In the Yakima, mid-Columbia steelhead are listed as threatened (1999, 64 FR 14517). We propose to identify how to contribute to steelhead delisting by running EDT in the Naches River (the largest tributary to the Yakima River). We will use EDT to predict production in the Naches River under different discharge regimes. The EDT analysis will provide water managers with rankings of benefits for each discharge regime. Water managers use this information in future water delivery decision processes. The EDT modeling process is intended to provide managers with information that will lead to the highest likelihood of success which should lead to recovery of listed fish populations.
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