River GeoDSS for Agroenvironmental Enhancement of Colorado's Lower Arkansas River Basin. II: Evaluation of Strategies

Research conducted at the field and regional scales in the Lower Arkansas River (LAR) Valley of Colorado has identified water management alternatives with potential for enhancing agroenvironmental conditions in the basin by reducing waterlogging and soil salinity, salt loadings to the river, and nonbeneficial evapotranspiration in the irrigated stream-aquifer system. The LAR geospatial decision support system (GeoDSS), presented in a companion paper as a customized version of the generalized River GeoDSS, is applied to the evaluation of the feasibility and performance of water management strategies at the basin scale. The LAR GeoDSS allows comparative evaluation of management options for improving irrigation efficiency, minimizing water shortages, and improving water quality at selected control points by augmenting groundwater return flows through dynamic regulation of reservoir releases to abide by legal and administrative constraints on river operations. Results show that conditions favorable to increased agricultural productivity and water conservation can be accommodated, along with the benefits of improved river water quality through reduction of excess irrigation recharge and canal seepage and augmented subsurface drainage, without violating existing water rights and the Colorado-Kansas Interstate Compact Agreement.