Dissolved selenium concentrations were higher during nonirrigation season than during irrigation season at tributary sites. coli, the lack of concurrent total recoverable iron and streamflow information represents a data gap, which needs to be addressed to compute annual loads.ĭissolved selenium concentrations and loads were evaluated at 20 tributary sites using discrete water-quality data collected 1991–2018. None of the sites had enough concurrent total recoverable iron and streamflow data to compute annual loads. Concentrations were often an order of magnitude higher in samples collected during irrigation season than in samples collected during nonirrigation season.
The chronic aquatic-life water-quality standard (1,000 µg/L) was exceeded in most irrigation season (April through October) samples but was rarely exceeded in nonirrigation season (November through March) samples. Median total recoverable iron concentrations ranged from 211 to 4,670 micrograms per liter (µg/L). Total recoverable iron concentrations and loads were evaluated at 15 tributary sites for samples collected from August 1993 to February 2018. coli concentrations were measured at the most upstream site, Leach Creek at Summer Hill Drive. coli concentrations showed no consistent downgradient increase in Leach Creek. coli in samples ranged from 25.9 to more than 2,420 CFU/100 mL, and geometric mean concentrations at sites ranged from 160 to 259 CFU/100 mL. coli concentration was measured between the two most upstream sites. coli concentrations generally increased in the downstream direction in Adobe Creek however, increases were not seen between all sites.
coli concentrations in samples ranged from 45.7 to more than 2,420 CFU/100 mL (method upper reporting limit for undiluted samples), and geometric mean concentrations at sites ranged from 301 to 1,180 CFU/100 mL. coli concentrations at sites along Adobe Creek and Leach Creek exceeded the State recreational use standard of 126 colony forming units per 100 milliliters (CFU/100 mL). Sample data were available at five sites along Adobe Creek and at six sites along Leach Creek, the two tributaries in the study area that are impaired for E. This study analyzed water-quality and streamflow data for 3 main-stem sites (2 sites along the Colorado River and 1 site along the Gunnison River) and 29 selected sites on tributaries to the Colorado River. coli, total recoverable iron, and dissolved selenium using existing data and (2) identify water-quality data gaps to inform future monitoring strategies. Geological Survey, in cooperation with the Grand Valley Drainage District and Colorado Water Conservation Board, conducted a study to (1) characterize concentrations, loads, and load reductions for E. The Colorado Department of Public Health and Environment Water Quality Control Division is required to develop total maximum daily loads for these constituents in these tributaries. coli), total recoverable iron, and dissolved selenium. The GVDD service area includes the lands from Palisade to Loma on the North side of the Colorado River.Tributaries to the Colorado River in the Grand Valley in western Colorado (segment COLCLC13b) have been placed on the State of Colorado 303(d) list as impaired for Escherichia coli (E. Today, this drainage system consists of over 260 miles of open and piped drains and over 14 miles of tailpipes throughout Mesa County and is maintained by Grand Valley Drainage District.
Grand valley drainage diatrict gj sentinel series#
In the early 1900’s, The Bureau of Reclamation began funding the construction of a series of open drains to handle the abundant irrigation tail water and subsurface seep conditions caused by new canals and irrigation laterals. Grand Valley Drainage District is vital because: Formed on September 7, 1915, the district is responsible for safely returning ground water, irrigation water and storm water to the Colorado River. The Grand Valley Drainage District is a Special District that is a division of local government. For more than a century, the Grand Valley Drainage District has worked for the residents of the grand valley to make sure that people’s land, crops, and homes were safe from drainage problems. The movement of this water as it returns across property can sometimes cause problems. The portion that is not consumed is returned to the Colorado River. Some of this water is diverted for irrigation and landscaping. This renewable resource is delivered to the Grand Valley by a system of canals every year.
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