Simulation of selected reservoir operations in the upper Truckee River Basin, California

Abstract

After decades of litigation and negotiation, the Truckee Carson-Pyramid Lake Water Rights Settlement Act was passed in 1990. The law provides a foundation for developing operating criteria for interstate allocation of water to meet demands for municipal, irrigation, fisheries and wildlife, and recreational uses, as well as to meet water-quality standards, in the approximately 7.000square-mile Truckee River and Carson River Basins of western Nevada and eastern California (fig. 1). The Truckee-Carson Program of the U.S. Geological Survey (USGS) is assisting the U.S. Department of the Interior in implementing the act. The program has the following objectives: Consolidate streamflow and water-quality data from several agencies into a single data base; Establish new streamflow and water-quality gaging stations for more complete water-resources information and more-consistent support of river operations; and Build, calibrate, test, and apply interbasin hydrologic computer models to support efficient water-resources planning, management, and allocation. Hydrological Simulation Program-Fortran A computer model simulating storage, flow, and quality of the water in the Truckee River and Carson River Basins and in the Truckee Canal is being developed to help meet the third objective of the Truckee Carson Program. The model, based on the Hydrological Simulation Program-Fortran (HSPF; see Bicknell and others, 1993), simulates reservoir and diversion operations to analyze alternative water-management scenarios. This fact sheet summarizes some of the capabilities that were added to HSPF to simulate complex reservoir operations in the upper Truckee River Basin in eastern California. Examples of such operations include releases based on water-storage and floodcontrol criteria; releases to meet agricultural, municipal and industrial, and hydropower demands; and exchanges of water categories' between reservoirs. In this summary, simplified or isolated examples are used to illustrate specific reservoir operations that can be represented by HSPF. Actual day-today system management or simulation is more complex. It requires consideration of present and forecast flow conditions and of reservoir stages and volumes at various locations in the river basin as well as compliance with numerous legal agreements, legal decrees, and demands. A category of water is any block of water that is individually accounted for in an observed or simulated water budget. A single river, reservoir, lake, or diversion ditch may contain several categories. Water within a category may have specific ownership, such as "privately owned stored water." or have a designated use, such as "pooled water" (used to meet a minimum-flow requirement known as Floriston rates).

River and Reservoir Operations Model, Truckee River basin, California and Nevada, 1998

“…2). The boundaries of these subunits generally conform to published hydrographic boundaries for consistency with previous work (Berris, 1996, andBrown andothers, 1986).…”

“…1). This subunit is a combination of subunits previously described in Brown and others (1986) and Berris (1996) fig. 2 and pl.…”

“…101-618. Berris (1996) developed a physically based flow-routing model of the Truckee River. The model routed daily mean streamflow along 114 miles (mi) of the mainstem Truckee River from just downstream from Lake Tahoe, Calif., to just upstream from Pyramid Lake, Nev. Hess (1996) developed a similar flow-routing model for the Carson River from the gaging station at East Fork Carson River near Markleeville, Calif., (italicized words are formal names for data-collection sites) and the gaging station at West Fork Carson River at Woodfords, Calif., to the gaging station Carson River at Fort Churchill, Nev., just upstream from Lahontan Reservoir.…”

“…This subunit includes the drainage area and surface of the lake, and the drainage area of the Truckee River between the outlet of the lake and the Farad gaging station. It is a combination of subunits previously described in Brown and others (1986) and Berris (1996): the 506-mi 2 Lake Tahoe subunit, which includes the drainage area and 192-mi 2 surface of the lake, and the 426-mi 2 upper Truckee River subunit, which includes the drainage area of the Truckee River between the outlet of the lake and the Farad gaging station. Mean annual runoff at the Farad gaging station for water years 1909-97 is 554,500 acre-ft (U.S.…”

“…This interface has shifted several miles during this century because of the varying lake levels. To provide a stable reference point for modeling and measurements, Marble Bluff Dam was chosen as the boundary between the lower Truckee River and Pyramid Lake subunits previously described in Brown and others (1986) and Berris (1996).…”