On April 21, 2020, the WSWC wrote a letter to Tim Petty, Assistant Secretary, Water and Science, U.S. Department of the Interior, expressing strong support for the current Sustainable Land Imaging (SLI) partnership between NASA and Interior’s USGS. “This involves a long-term commitment that includes the future launch of Landsat 9 and continuing work on ‘Landsat Next’ options and opportunities.”
Water managers are increasingly using Landsat-derived data and maps to monitor and manage water rights, both spatial and temporal data (seasonal and inter-annual), as well as evaluate beneficial consumptive use. Typical applications include mapping irrigated lands (by far the predominant use of water in the West), as well as crop type; measuring, monitoring, and mapping evapotranspiration and consumptive surface and groundwater use; and allocating and administering state water rights, including approval of water rights transfers and consideration of water right “calls” based on seniority.
States also use the data to administer negotiated agreements, monitoring interstate compacts and tribal water rights settlements. The data is also used to monitor agricultural fallowing and conservation reserve programs, outdoor urban uses and conservation measures, to evaluate water and food sustainability and security, and to inform forecasts and moderate agricultural market fluctuations. Environmental monitoring using Landsat data involves water use by invasive species (such as tamarisk or salt cedar) and the effectiveness of control strategies, as well as identify and monitoring wetlands, endangered and threatened aquatic species habitat, water quality parameters and harmful algal blooms.
Some of the state agencies using Landsat data as an element of their water planning and water rights management programs include the California Department of Water Resources (DWR), Colorado Division of Water Resources, Idaho DWR, Montana Department of Natural Resources and Conservation, Nebraska Department of Natural Resources, Nevada DWR, New Mexico Office of the State Engineer (OSE), Wyoming OSE, as well as the North Platte Decree Committee and a growing number of water conservation and irrigation districts.