词条 | Closed Basin Project |
释义 |
| USA |relief = 1 | width = 240 | lat = 37.54 | long = -105.67 | caption = Location of Closed Basin Project in the western United States }} The Closed Basin Project is a groundwater extraction project in the San Luis Valley in Colorado, United States, operated by the United States Bureau of Reclamation. LocationA closed basin is a hydrologic basin that has no outlet for the water. Precipitation can only leave through evaporation or seepage. The closed basin of the San Luis Valley covers {{convert|2940|sqmi}} between the San Luis Hills in the south, the San Juan Mountains to the west, Poncha Pass to the north and the Sangre de Cristo Mountains to the east.{{sfn|Alamosa Field Division Staff|1996|p=2}} The basin is separated by a hydraulic divide at the southern end from the Rio Grande watershed.{{sfn|The Closed Basin Project - RGWCD}} It contains the towns of Center, Hooper, Moffat, Mosca and Saguache and the Great Sand Dunes National Park and Preserve.{{sfn|Beck|2012}} Streams that flow into the basin include irrigation diversions from the Rio Grande, the Carnero, La Garita, and Saguache creeks from the west, San Luis Creek from the north, and the North Crestone and Sand creeks from the east. The water spreads over the floor of the valley and either sinks into the underground aquifer or evaporates. The lowest part of the basin extends from the San Luis lakes north to the Blanca Wildlife Habitat Area.{{sfn|Beck|2012}} In this area the water table is very close to the surface. Water can evaporate directly from the soil or be taken up by plants such as salt grass, rabbit brush and greasewood, which release the water through evapotranspiration.{{sfn|Alamosa Field Division Staff|1996|p=2}} ProjectThe Closed Basin Project was authorized by Congress in 1972 to extract groundwater from the lowest part of the basin in an area that covers {{convert|195|sqmi}}. Colorado uses the water as part of its contribution to the Rio Grande Compact of 1939, making more water available for irrigation in Colorado. It also helps the United States meet its 1906 treaty obligations with Mexico for supply of water from the Rio Grande.{{sfn|Beck|2012}} The project, managed and maintained by the Bureau of Reclamation with civil maintenance by the Rio Grande Water Conservation District, extracts groundwater through a network of shallow wells and delivers it through the 42-mile (68 km) Franklin Eddy Canal to the Rio Grande. Some of the water is delivered to the Alamosa National Wildlife Refuge, the Blanca Wildlife Habitat Area and San Luis Lake.{{sfn|Alamosa Field Division Staff|1996|p=2}} 170 salvage wells were built ranging in depth from {{convert|85|to|110|ft}} and delivering {{convert|50|to|1100|gal}} per minute. There are about {{convert|115|mi}} of pipeline laterals that carry water to the conveyance channel.{{sfn|Alamosa Field Division Staff|1996|p=2}} The channel has a PVC lining covered with {{convert|12|to|16|in}} of aggregate and fill, with a capacity that expands from {{convert|45|to|160|ft3}} per second from north to south. Trees have been plated along the channel in the areas that are most susceptible to wind erosion, watered through drip irrigation systems.{{sfn|Alamosa Field Division Staff|1996|p=3}} Water flows along the channel at about {{convert|1|ft}} per second. More than 132 observation wells are used to measure water level or pressure from the aquifers, with the data used to ensure the project stays within the authorized drawdown limits.{{sfn|The Closed Basin Project - RGWCD}} ResultsUnder the law that authorized the project, water levels in wells that existed outside the project boundary before pumping started must not drop more than {{convert|2|ft}}, and water with more than 350 parts per million total dissolved solids cannot be used. About 60 of the 170 wells in the project are closed down because of the drawdown limits, and eleven because of the water quality requirements. The original estimate was that the project would deliver {{convert|100000|acre.ft}} annually. This has never been achieved.{{sfn|Beck|2012}} Since 2000 the average annual output has been around {{convert|17300|acre.ft}} annually.{{sfn|The Closed Basin Project - RGWCD}} ReferencesCitationsSources{{refbegin}}
|ref=harv |url=http://geosurvey.state.co.us/education/Documents/San_Luis_Valley_Project,Closed_Basin_Division,Colorado.PDF |author=Alamosa Field Division Staff |publisher=Bureau of Reclamation |year=1996 |title=SAN LUIS VALLEY PROJECT, CLOSED BASIN DIVISION, Colorado |accessdate=2012-10-08 }}{{dead link|date=November 2016 |bot=InternetArchiveBot |fix-attempted=yes }}
|last=Beck|first=Ken |date=12 April 2012 |title=The Closed Basin Project |publisher=Rio Grande Watershed Conservation and Education Initiative |accessdate=2012-10-08}}
|title=The Closed Basin Project |publisher=Rio Grande Water Conservation District |accessdate=2012-10-08}}{{refend}}{{Rio Grande dams and diversions}} 2 : Economy of Colorado|Water in Colorado |
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