Gila River Indian Community water resources decision support system - a modeling system for managing a multi-source conjunctive use water supply for long-term sustainability
Date
2006-10
Authors
Westfall, Brian D., author
Keller, Andrew A., author
Bliesner, Ronald D., author
Flynn, Tim, author
Lindstrom, Shane, author
U.S. Committee on Irrigation and Drainage, publisher
Journal Title
Journal ISSN
Volume Title
Abstract
The Gila River water rights settlement will restore to the Gila River Indian Community (GRIC) a water supply necessary to meet present and future demands on their tribal homeland. The settlement provides water from nine water sources, including delivery from four irrigation districts, treated municipal effluent, irrigation return flow and supplemental groundwater. The Gila River Indian Community Water Resources Decision Support System (WRDSS) was developed to effectively manage this complex water supply and protect the underlying aquifer. The WRDSS consists of three model components: Overall Water Resource Analysis (OWRA); Interface Manager (IM); and the Ground Water Analysis (GWA). The OWRA model component tracks water delivery and the salt load from a water source to any delivery point through a branching flow network. Water supply preferences and priorities can be specified for each user for each water source. Water is delivered based on supply preference when water is abundant and by priority when water is short. Seepage and evaporation losses in the delivery and drainage systems, deep percolation from agricultural nodes, and costs and returns are also computed by the OWRA. The OWRA is tied to the GWA via the Interface Manager. The Interface Manager is the tool used to convert output from the OWRA to a format that is compatible with the input requirements of the GWA. The OWRA estimates deep percolation and seepage from the conveyance network and irrigated areas. The IF spatially maps these groundwater recharge inputs to the grid cell network used in the GWA model. Any groundwater demand expressed by the OWRA is also specified as an input to the GWA on an established timestep. The Ground Water Analysis component is a modeling tool based on MODFLOW (MacDonald and Harbaugh, 1988), to simulate surface/groundwater interactions and groundwater flow conditions, and MT3D (Zheng, 1990) to evaluate changes in groundwater quality over time. The GWA is used to evaluate the groundwater demand, in terms of yield and water quality, specified by the OWRA. As the groundwater demand changes so do the economics of pumping and water quality. This requires iterations between the OWRA and the GWA.
Description
Presented at Ground water and surface water under stress: competition, interaction, solutions: a USCID water management conference on October 25-28, 2006 in Boise, Idaho.