Evaporation is a highly uncertain component of water budgeting and modeling efforts at lake powell

The Bureau of Reclamation awarded a $292,760 Cooperative Agreement under the SECURE Water Act – Research Agreements program (CFDA 15.560) to the Desert Research Institute (DRI), operating under the Nevada System of Higher Education, for continuation of in-situ evaporation monitoring at Lake Powell. The award, effective June 20, 2025, through June 30, 2028, funds real-time data collection activities that build upon a seven-year evaporation study (2017-2024) conducted at the reservoir. DRI will collaborate with the U.S. Bureau of Reclamation's Technical Service Center and Upper Colorado Basin Regional Office to maintain over-water meteorological observation equipment, replace aging sensors, and generate evaporation estimates supporting water resource operations and management models across the Colorado River Basin.

The primary deliverables include continuous evaporation data collection and processing, sensor equipment replacement and maintenance, and evaporation estimates for incorporation into the Colorado River Simulation System (CRSS), Colorado River Mid-Term Modeling System (CRMMS), and Lake Powell CE-QUAL-W2 water quality model. Additionally, the project will provide in-situ benchmark data to support remote sensing and evaporation modeling validation efforts conducted by the Bureau of Reclamation throughout the western United States. The work involves coordination across multiple technical teams, including the Research and Modeling Group, River Operations Group, and Water Quality Group, leveraging existing tools and infrastructure established during the initial seven-year study.

To improve estimates from the reservoir, the upper colorado basin regional office funded a targeted in-situ evaporation study from 2017 to 2024. The project has generated the longest continuous record of over water meteorological observations and evaporation estimates ever collected at lake powell and established standard methods and processing routines for future data collection and estimation (reclamation 2022). These observations are being used by engineers in the upper basin to update evaporative loss coefficients in the colorado river simulation system (crss) and colorado river mid-term modeling system (crmms) and to improve the lake powell CE-qual-W2 water quality model. The intent of the proposed facilitated adoption project is to continue over water data collection at lake powell, leveraging tools, team, and equipment already in-place, to support in-situ evaporation monitoring on the reservoir over the next three years. The project team will include members from the technical service center, desert research institute (DRI), and upper colorado basin regional office, including members from the research and modeling group, river operations group, and water quality group. Specifically, DRI will collaborate with researchers from the united states bureau of reclamations (usbr) technical service center (TSC) to continue real-time data collection, replace aging sensors and equipment, and produce evaporation estimates for incorporation in water operations, water quality, and water accounting modeling in the upper colorado basin regional office. Data collected by this effort will also provide benchmark in-situ estimates for ground validation of ancillary reservoir evaporation remote sensing and modeling efforts being performed by reclamation throughout the western U.S.