Flynn, Timothy J., authorBannister, Peter S., authorBliesner, Ronald D., authorKeller, Andy A., authorLindstrom, Shane, authorU.S. Committee on Irrigation and Drainage, publisher2020-06-012020-06-012006-10https://hdl.handle.net/10217/207270Presented at Ground water and surface water under stress: competition, interaction, solutions: a USCID water management conference on October 25-28, 2006 in Boise, Idaho.The Gila River Indian Community's Water Resources Decision Support System (WRDSS) provides an operations and planning tool for managing a multi-source water supply to sustain the Community in their tribal homeland. The Gila River Indian Community Water Right Settlement Act of 2003 provides water from nine sources, including imported surface water supplemented with groundwater. These sources are needed to meet multiple water supply needs including agricultural use by the Gila River Indian Community. The expansion of irrigated agriculture, importation of surface water, and increased groundwater withdrawal within the Reservation will change the long-term groundwater balance - in terms of both quantity and quality. Managing and protecting the groundwater resource for multiple purposes within the framework of the Community's water resource management goals, objectives, and economic constraints is a key component for long-term water supply sustainability. The Groundwater Analysis (GWA) is one of three components of the WRDSS. It is linked to an Overall Water Resources Analysis (OWRA) module, which manages the conjunctive use of surface water and groundwater supplies, via an Interface Manager (IM) component. The GWA is a modeling tool based on an analytical model for unsaturated flow and salt transport in the vadose zone, the numerical groundwater flow model (MODFLOW), and a numerical solute transport model (MT3D) for salt transport in groundwater. The GWA is used to evaluate aquifer yield and water quality constraints in response to meeting water supply demand specified by the OWRA. It also provides a management tool to forecast potential impacts and assess management strategies for long term sustainability of the groundwater resource.born digitalCD-ROMsproceedings (reports)engCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.Text