A Decision Support Tool To Help Water Managers In The Colorado River Basin In Utah

As populations in the Western U.S. continue to grow the need for clean and accessible water grows as well. Little can be done to increase water supply from nature, but changes in management decisions and infrastructure may help ensure each drop of water is purposefully used. This paper focuses on the development of the Utah Colorado River Accounting and Forecasting – Decision Support Tool (UCRAF-DST) to help assess both water budgets (supply, consumptive use, losses, etc.) and water rights for the Colorado River Basin (CRB) in Utah. The UCRAF-DST has three main components: data collection and processing, depletion-runoff calculator, and RiverWare Model(s). Using the RiverWare modeling system as the computational hub, the UCRAF-DST implements high-resolution canal, field, and evapotranspiration rates (OpenET) to accurately account for consumptive use calculations. Losses due to conveyance (e.g., lined vs unlined canal), application method (e.g., sprinkler vs flood irrigation), and irrigation efficiency (e.g., overspray, surface runoff, etc.) are calculated at the field-level and then aggregated to the canal-level before inclusion into RiverWare. The overall goal of the UCRAF-DST is to develop a comprehensive understanding of current water rights and water usage at the HUC-8 basin-scale for the CRB in Utah and to create a planning tool to evaluate how changes (e.g., crop types, irrigation methods, water reduction methods, water right transfer, curtailment, etc.) affect water availability and water rights. This knowledge can then be used to make water management decisions that ensure sustainable water resources within the CRB of Utah.

This paper will also detail implementation of UCRAF-DST for the Duchesne River Basin in Utah, which was chosen as the proof of concept for this project for multiple reasons, including the high use of water for both municipal (Strawberry Aqueduct and Collection System) and irrigation purposes.