WSP12894 - Laserfiche WebLink

Home Browse Search

III. Introduction: Water Issues in the Lower South Platte Basin 1.0 Water Issues in the Lower South Platte Basin The South Platte Basin accounts for nearly 70% of Colorado's total population containing 2.7 million people. Colorado is one of the fastest growing states in the country, 23% growth from 1990 to 1998. Some 9 ditches and tunnels transport over 400,000 acre-ft of water from the North Platte, the Colorado, and the Arkansas River Basins to the South Platte River Basin (CWCB,2001a). The South Platte basin in Colorado has an unconsolidated alluvial aquifer that contains about 8 million acre- ft of storage. The lower portion of the basin in Colorado uses wells to obtain irrigation water from the aquifer. Annual groundwater pumping averages 418,000 acre-ft (Hurr et aI., 1975). The primary direct surface water delivery in the South Platte and Republican River Basins is agriculture, delivering over 2.2 million acre- ft annually. An additional 630,000 acre-ft per year are delivered to meet municipal and other uses, and 1.25 million acre-ft are delivered for storage, augmentation and recharge activities. Total surface water delivery in 1998 was over 4 million acre-ft (CWCB, 2001a). Flows in the Platte River have been fully appropriated at certain times of the year since the late 1800s. The historical use of water has been primarily for agricultural development. According to the United States census of 1910, Colorado had more land under irrigation than any other State of the Union. Currently, the irrigated acreage in the South Platte River basin totals between 1.1 and 1.4 million acres. Com (57%), hay (26%), dry beans (7%), winter wheat (6%) and barley (3%) represent the major irrigated crops in the basin. At least four federally listed endangered bird species may be found on the Platte at different times of the year:. whooping crane, interior least tern, piping plover, and peregrine falcon. There are also several native fish species that are listed as threaten or endangered species by Colorado and one fish (pallid sturgeon) is federally listed in Nebraska. Water management on the South Platte River may affect both groups of animals. In Kuhnhardt and Fontane, (1995) the authors point out that the South Platte River system is operating closer and closer to its absolute capacity (because of growing urban population and new mandates for instream flows). The authors believe that partial solutions may lie in better coordination of reservoir operations, further development of conjunctive use potential, and more innovative trading and cooperation between decreed water users. The focus of this project is to develop tools for conjunctive management of ground and surface water to improve tools for water resources management. The SPMAP project provides valuable tools for water managers in the South Platte basin who protect and provide water to agricultural and municipal users. It is especially important to accurately determine the timing and amounts of groundwater withdrawals and the subsequent river depletion effects and augmentation requirements on the South Platte River. Also, the consumptive use of water rights needs to be accurately calculated for water transfers. Good data and tools also help manage recharge efforts to benefit streamflow critical for threatened and endangered species and to ensure a stable water supply for the diverse uses along the South Platte River. Completion Report: South Platte Mapping and Analysis Program 3