Purpose and Need

The primary purpose of the URGWOM is to facilitate more efficient and effective accounting and management of water in the Upper Rio Grande Basin. Historically, water of the Rio Grande has been used primarily for crop irrigation; however, rapid population growth in the Basin and urbanization in many areas has resulted in increasing and diversifying demands on the hydrologic system. Water management decisions are becoming increasingly complex and difficult because of the broad range of interests and issues that must now be addressed including flood control, irrigation demands, transmountain diversions, the Rio Grande Compact, municipal and industrial demands, Native American water rights, Endangered Species Act compliance, and recreational uses. As water supply is limited, higher levels of precision and reliability in water accounting and forecasting are required.

A fundamental need to be addressed through continued computational modeling with URGWOM is assisting managers in delivering supplies to all entitled water users on time, in the desired quantities, and with minimum conflict between users with specific focus on deliveries, exchanges, and leases of water allocated to contractors for San Juan-Chama Project water. Accurate and up-to-date water accounting is essential to meeting this need which is done efficiently through computerized data collection, accounting in URGWOM, and reporting. URGWOM is used to provide the community of water managers and water users with a clear, consistent, and common set of data to formulate, evaluate, and support decisions.

Water accounting with URGWOM is used to track the status of water for Compact deliveries, international treaty obligations, Native American water rights, contracts, etc. Additional water accounting procedures are required to adjust the Compact index river gage data so that the imported San Juan-Chama Project water is taken out of the flow record for an accurate determination of native water for Compact purposes.

Water is stored annually in El Vado Reservoir to ensure the prior and paramount water rights of 8,847 acres of the Six Middle Rio Grande Pueblos. This amount of water is provided under Section 11 of the March 17, 1980 agreement between the Secretary of the Interior and the Middle Rio Grande Conservancy District (MRGCD). Accounting procedures are needed in the model to differentiate this water from other native water and the San Juan-Chama Project water in the system.

Several of the major metropolitan areas in the Rio Grande Basin are shifting to conjunctive use of their available water resources. This water use strategy allows municipal water managers to meet increasing water demand by using both groundwater and surface water supplies. These conjunctive use strategies require detailed and reliable accounting to ensure that groundwater pumping effects are offset by reservoir releases that keep the river whole for downstream users. These changes impact the needs for modeling with URGWOM.