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INTRODUCTION Anadromous salmonids in the Pacific Northwest are in decline, and several species and stocks have been listed as threatened or endangered. Thus, resource managers are proposing drastic and radical changes to the hydrology and water levels on the Columbia and Snake rivers. Alternatives will be developed which will benefit salmonids but also will have secondary impacts on other fish and wildlife resources in the Columbia River. The USGS Western Fisheries Research Center (WFRC) and the Upper Midwest Environmental Sciences Center (UMESC) are collaborating to build a spatial decision support system (DSS) which planners and managers can use for assessments of salmonid survival and management options for the aquatic and terrestrial resources. The Centers have unique capabilities that will be brought together to provide resource managers with information that can be used to determine the impacts of the proposed water level manipulations if they occur. Staff at the WFRC will provide expertise on hydraulic modeling and fishery impacts of the proposed actions, and staff at the UMESC will provide expertise on terrestrial ecology and wildlife impacts. John Day Reservoir was created on the Columbia River in 1968 for power generation, navigation, flood control, and irrigation. The reservoir is approximately 80 miles in length, and water levels in the forebay of John Day Dam fluctuate about 11 feet under current operating conditions. However, fisheries managers are proposing permanently drawing the reservoir down by as much as 100 ft. in an effort to improve survival of endangered anadromous salmonids. The lowered water levels are expected to increase water velocities within the reservoir, and to restore normative riverine functions to the upper portion of the reservoir under partial drawdown, or to the entire river under a drawdown to natural river levels. The increased water velocities are expected to reduce the time it takes for outmigrating juvenile salmonids to reach the estuary. It has also been suggested that predation on juvenile salmonids will be reduced because encounter rates with predators will be reduced. Water level manipulations will affect upland and wetland habitats bordering the reservoir. Specifically, water level drawdowns will have significant impact on the operation and management of the 23,555 acre Umatilla National Wildlife Refuge (NWR). The Umatilla NWR was established in 1969 as a mitigation project for the impacts of flooding caused by hydropower development. There will be a need to develop a new management plan for this refuge if water levels within the reservoir are lowered. By building a DSS framework for this assessment we will meet many needs of policy-makers and resource managers by providing mapping capability of land and biological resources, a common digital database for information, a suite of spatial analysis tools, display of predictive population and predation models, and basis for land management alternatives. The system would provide for the integration of biological and physical themes so that decisions could be made on the best available science and data. The DSS will provide for the creation of a variety of digital and paper products. PLAN OF STUDY Spatial Data Acquisition This process will begin with communication with Federal and State management entities to determine needs and priorities. The WFRC and UMESC are inventorying all in-house data relevant to the John Day Reservoir at the present time. We will assemble all data with a spatial extent into an ArcView project(s). Additionally, we will add the following: 1) Clipped and edge-mapped Digital Raster Graphics (DRGs) and Digital Orthophoto Quads which are available for the area of the John Day Reservoir and Umatilla National Wildlife Refuge. These would include digital line graphics for roads, streams, etc. (The DRGs have been acquired by the WFRC, and are being processed by the UMESC). 2) Digitally rectified infrared or true color photographs (most recent series, if available) for the John Day Reservoir and Umatilla National Wildlife Refuge. 3) The Centers will initiate contacts with the U.S. Fish and Wildlife Service, U.S. Army Corps of Engineers, the State of Washington, and the State of Oregon to determine if other spatial themes might be available and applicable. Hydraulic & Habitat Modeling The WFRC will conduct two-dimensional hydraulic modeling that will result in estimates of bathymetry and mean column water velocities for four water levels (normal operating pool, minimum operating pool, spillway crest, and natural river) and three discharges (90%, 50%, and 10% exceedence). These modeling efforts will provide information on the physical habitat that may be expected under each scenario. The affects of water level manipulations on biotic habitats (aquatic and terrestrial) will be estimated through a variety of predictive modeling methods. Traditional methods that derive an index of habitat quality such as the Habitat Evaluation Procedures developed by the U.S. Fish and Wildlife Service can be incorporated as well as newer methods that are under development. Fisheries Issues The WFRC is conducting research that can be used to model the distributions of outmigrating juvenile salmonids and their predators and other species of interest such as white sturgeons. The resource selection functions derived from these efforts will be incorporated to provide managers with information on how habitats for these species and interactions among species can be expected to change under each scenario. Other approaches that may be incorporated include the Interaction Assessment (INTASS) methodology also under development at the WFRC. This approach recognizes that one of the major difficulties faced by resource managers when making management decisions is the fact that the ecological consequences of their actions are often almost impossible to predict. For example, an action designed specifically to aid a stream population of fish, by virtue of altering habitat, may more effectively aid a competitor or inadvertently harm a food species, resulting in an adverse affect on the species intended to be benefited by the action (i.e. the introduction of Mysis sp. as food to benefit resident salmonids). INTASS uses a data analytic technique, together with a generalized (non-species specific) class of population models, to predict the outcome of management actions before they are implemented. This ability to conduct what-if scenarios to see how consequences play out through the web of species interactions and thus ultimately affect the target species or community of species of interest will be unique to this DSS. Wildlife Issues The UMESC’s goal is to assist the Umatilla NWR to develop a new management plan that will consider options if reservoir drawdown is undertaken. Currently, the Refuge is a varied mix of open water, slough, shallow marsh, riparian woodlands, seasonal wetlands, cropland, islands, and shrub-steppe upland habitats. The Refuge is vital to migrating waterfowl, bald eagles, colonial nesting birds, and other migratory and resident wildlife. Impoundment of John Day Reservoir stabilized the water table and allowed native plants such as cottonwoods, willows, cattails, and bulrushes to appear in previously desert environments. Manipulating water levels in the reservoir will cause changes to the habitats available for wildlife. These changes may cause the Refuge to alter the current management goals and objectives. The UMESC will assist the Refuge to determine what changes may be expected to occur on Refuge lands affected by water level manipulations. The UMESC will also help to identify actions that may be undertaken, such as the creation of moist soils management units, so the Refuge can continue to function in its mission. Project Contact Michael J. Parsley Email: mike_parsley@usgs.gov Publications
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