Utah Colorado River Accounting and Forecast Decision Support Tool (UCRAF-DST)

Precision has teamed up with Follum Hydrologic Solutions (FHS) in developing the Utah Colorado River Accounting and Forecast Decision Support Tool (UCRAF-DST). The UCRAF-DST is being developed for the Colorado River Authority of Utah (Authority) as part their effort to support drought mitigation strategies. The UCRAF-DST analyzes agricultural water use in the Duchesne, Price, and San Rafael River Basins at a field scale level enabling CRAU to improve drought resiliency by assessing different drought mitigation planning methods.

The UCRAF-DST integrates a Diversion-Runoff Calculator (DRC) developed by FHS, and a water rights and accounting model built in RiverWare® by Precision. The DRC has been built to determine Net Irrigation Water Requirement (NIWR) at the field scale, which is aggregated to the canal- and basin-scale. It is a geospatial tool, incorporating irrigated land use data, water rights information, and canal connectivity data. The DRC is capable of estimating NIWR by incorporating field and canal attributes such as crop type, irrigation type, acreage, water rights, canal length, canal type, and location. This data is incorporated with historic data to estimate Evapotranspiration (ET). Alternatively an estimate of ET from OpenET can be used to determine the NIWR. Lastly, the DRC estimates return flows to each adjacent field, canal, and stream reaches.

The RiverWare model ingests data from the DRC including estimates of NIWR, Canal Losses, and return flows. The RiverWare model uses this information to estimate stream flows, diversions, and water rights administration in the basin over the historical period. The tool then allows for perturbations at the field level in the form of fallowing, changing of crop type, or changes in conveyance characteristics to determine a changed NIWR. That new requirement is passed to the RiverWare model and a drought mitigation strategy can be compared to the baseline characterization. The comparison of the baseline simulation to the changed allows the Authority to analyze potential drought mitigation strategies.

The UCRAF-DST is a state-of-the-art model that estimates Natural Inflows to a basin, characterizes the mass balance of the basin physically. The UCRAF-DST characterizes physical and administrative changes to the system, enabling estimates conserved water. Estimates of conserved water is crucial to the CRAU to assess different drought mitigation strategies that have been proposed through new programs and legislation within the Stat of Utah.