The Omnibus Public Land Management Act of 2009 (Public Law 111-11) was passed into law on March 30, 2009. Sub-title F of the law, also known as the SECURE (Science and Engineering to Comprehensively Understand and Responsibly Enhance) Water Act, calls for the establishment of a “national water availability and use assessment program” in the U.S. Geological Survey (USGS). The recommendation for a national assessment of the available water resources was driven by the lack of such an assessment since 1978. In fulfillment of the Act, the USGS developed the National Water Census (NWC), under the auspices of the USGS Water Availability and Use Program, and as part of that activity, among others, collected water withdrawal and wastewater return data, including instream use at hydroelectric powerplants (water use) for purposes of expanding upon national datasets and providing these data to assist in hydrologic studies of the Colorado River Basin. The NWC uses regional geographic studies, of which the Colorado River Basin was one of three pilot study areas, and topical-themed studies that are designed to improve the understanding of resources such as streamflow at non-streamgaged sites, ecological flows, groundwater/surface-water interactions, and effects of snow sublimation on timing and quantity of runoff. These datasets present instream and offstream water use estimates in 5 year intervals from 1985 to 2010 which are aggregated to the 8-digit (subbasin) hydrologic unit level for the Colorado River Basin.
These digital data accompany Maupin, M.A., Ivahnenko T. and Bruce, B., 2018, Estimates of water use and trends in the Colorado River Basin, southwestern United States, 1985-2010: U.S.Geological Survey Scientific Investigations Report 2018-5049, 61 p., https://doi.org/10.3133/sir20185049 .