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

Abstract

Abstract. Water management substantially alters natural regimes of streamflow through modifying retention time and water exchanges among different components of the terrestrial water cycle. Accurate simulation of water cycling in intensively managed watersheds, such as the Yakima River Basin (YRB) in the Pacific Northwest of the U.S., faces challenges in reliably characterizing influences of management practices (e.g., reservoir operation and cropland irrigation) on the watershed hydrology. Using the Soil and Water Assessment Tool (SWAT) model, we evaluated streamflow simulations in the YRB based on different reservoir operation and irrigation schemes. Simulated streamflow with the reservoir operation scheme optimized by the RiverWare model better reproduced measured streamflow than the simulation using default SWAT reservoir operation scheme. Scenarios with irrigation practices demonstrated higher water losses through evapotranspiration (ET), and matched benchmark data better than the scenario that only considered reservoir operations. Results of this study highlight the importance of reliably representing reservoir operations and irrigation management for credible modeling of watershed hydrology. Both SWAT and RiverWare are community-based and have been widely tested and applied for reservoir operations and agricultural watershed modeling in regions across the globe. As such, the methods and findings presented here hold the promise to apply to other intensively managed watersheds to enhance water resources assessment.

Reduction of sediment yield by riparian vegetation recovery at distinct levels of soil erosion in a tropical watershed

“…The Soil and Water Assessment Tool (SWAT) hydrological model (Arnold et al, 2012) is a semi-distributed, time-continuous, and process-based river watershed model that allows assessment of the impact of land use and management on soil and streams in small to large watersheds. SWAT has been applied in several studies worldwide for watershed planning and management (Betrie et al, 2011;Gassman;Sadeghi;Srinivasan, 2014;Bressiani et al, 2015;Vigiak et al, 2016;Khelifa et al, 2017;Kaffas;Hrissanthou;Sevastas, 2018;Gharibdousti;Kharel;Stoecker, 2019;Qiu et al, 2019;Rafee et al, 2019).…”

Effects of Irrigation on Water, Carbon, and Nitrogen Budgets in a Semiarid Watershed in the Pacific Northwest: A Modeling Study

“…Such perturbations in surface energy and water fluxes not only lead to surface cooling and decreases in Bowen ratios that modulate boundary layer evolution and convective processes in the atmosphere (DeAngelis et al, 2010; Harding & Snyder, 2012; Pei et al, 2016) but also influence the hydrologic budget. For example, previous studies (Leng et al, 2015; Qiu et al, 2019; Xu et al, 2019) have demonstrated that the hydrologic budget terms such as infiltration, percolation to deep soil layers, recharge to aquifers, and in turn baseflow at field, watershed, and large basin scales can be altered by irrigation.…”

“…Consequently, the carbon and nitrogen fluxes and stocks in irrigated lands are expected to differ significantly from those in unirrigated lands (Follett, 2001). Irrigation is therefore an indispensable component of the water budget that can strongly modulate agro‐ecosystem dynamics and biogeochemical cycling in semiarid watersheds, although its contribution to watershed functioning has not been sufficiently studied (Brown, 2011; Qiu et al, 2019).…”