Estimates of ground-water recharge to the Yakima River Basin aquifer system, Washington, for predevelopment and current land-use and land-cover conditions

Abstract

Two models were used to estimate groundwater recharge to the Yakima River Basin aquifer system, Washington for predevelopment (estimate of natural conditions) and current (a multi-year, 1995-2004, composite) land-use and landcover conditions. The models were the Precipitation-Runoff Modeling System (PRMS) and the Deep Percolation Model (DPM) that are contained in the U.S. Geological Survey's Modular Modeling System. Daily values of recharge were estimated for water years 1950-98 using previously developed PRMS-watershed models for four mainly forested upland areas, and for water years 1950-2003 using DPM applied to 17 semiarid to arid areas in the basin. The mean annual recharge under predevelopment conditions was estimated to be about 11.9 in. or 5,450 ft 3 /s (about 3.9 million acre-ft) for the 6,207 mi 2 in the modeled area. In the modeled areas, recharge ranged from 0.08 in. (1.2 ft 3 /s) to 34 in. (2,825 ft 3 /s). About 97 percent of the recharge occurred in the 3,667 mi 2 area included in the uplandarea models, but much of this quantity is not available to recharge the bedrock hydrogeologic units. Only about 1.0 in., or 187 ft 3 /s (about 0.14 million acre-ft), was estimated to occur in the 2,540 mi 2 area included in the semiarid to arid lowland modeled areas. The mean annual recharge to the aquifer system under current conditions was estimated to be about 15.6 in., or 7,149 ft 3 /s (about 5.2 million acre-ft). The increase in recharge is due to the application of irrigation water to croplands. The annual quantity of irrigation was more than five times the annual precipitation for some of the modeled areas. Mean annual actual evapotranspiration was estimated to have increased from predevelopment conditions by more than 1,700 ft 3 /s (about 1.2 million acre-ft) due to irrigation.

Implications of water management representations for watershed hydrologic modeling in the Yakima River basin

“…675 mm, with an average snowfall of 550 mm, occurring mainly in December and January. Rangeland, forest, and cropland are the primary land uses in the basin and cover 36 %, 33 %, and 28 % of the study area (Vaccaro and Olsen, 2007), respectively. Dams were built throughout the basin for the irrigated agriculture.…”

When Should Irrigators Invest in More Water‐Efficient Technologies as an Adaptation to Climate Change?

“…The YRB (Figure ) is an intensively irrigated agricultural basin of the western U.S.; agriculture is a significant part of its economy (USBR, ; Vaccaro & Olsen, ). The YRB is located in central Washington and has an area of 16,000 km 2 .…”

Numerical simulation of groundwater flow for the Yakima River basin aquifer system, Washington

“…Two models in the U.S. Geological Survey's Modular Modeling System (Leavesley and others, 1996) were used to estimate recharge: the Precipitation-Runoff Modeling System (PRMS) (Leavesley and others, 1983) and Deep Percolation Model (Bauer and Vaccaro, 1987;Vaccaro, 2007). The two models were used to simulate two different hydrologic regimes of the Yakima River basin (Vaccaro and Olsen, 2007a), and to estimate groundwater recharge for predevelopment and current land-use and land-cover conditions for those regimes ( fig. 14).…”

“…PRMS is designed for mountainous, snow-dominated environments. Four operational, calibrated PRMS models were available for estimating daily recharge (Mastin and Vaccaro, 2002) throughout about 53 percent of the extended study area, and they were used to estimate recharge for 1950-2003 (Vaccaro and Olsen, 2007a). The Deep Percolation Model originally was developed as a tool for estimating daily groundwater recharge over a broad array of landscapes and spatial-temporal scales and is best suited for areas dominated by agricultural irrigation.…”