Colorado ground-water quality
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Geology topics
Publications and source records attributed to Doug Cain.
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Irrigation-return flows in the lower Arkansas River valley of Colorado were investigated using one-time data at 59 sites, monthly data at 4 sites, and intensive data in a small irrigated area. Specific conductance of return flows increased downstream, paralleling specific conductance of irrigation water. During July 1977, Arkansas River streamflow below Manzanola was mostly irrigation-return flow. A similar situation existed during periods of little precipitation in the early and late irrigation seasons during 1974 to 1978. Irrigation-return flows had a large effect on Arkansas River water quality during these times. (USGS)
The Widefield aquifer near Colorado Springs, Colorado, is recharged primarily by Fountain Creek and, to a lesser extent, by infiltration and percolation of water from the land surface and from groundwater inflow. During the past 20 to 30 years, concentrations of nitrate (as nitrogen) in the Widefield aquifer have increased from 0.5 to 3.0 milligrams/L to nearly 10 milligrams/L, and occasionally exceed the drinking-water standard of 10 milligrams/L as nitrogen. During the summer of 1982, the concentrations of nitrite plus nitrate as nitrogen in water in the aquifer ranged from 3.2 to 15 milligrams/L with a mean concentration of 6.9 milligrams/L. In general, the nitrite-plus-nitrate concentrations are greatest near the north end of the aquifer, probably resulting from effluent from Colorado Springs Sewage Treatment Plant being discharged to Fountain Creek. During 1982, 93% of the total estimated 160 tons of nitrogen available to enter the Widefield aquifer was from the Colorado Springs Sewage Treatment Plant. However, a significant proportion of this nitrogen may have been lost through denitrification. (USGS)
Water used for agriculture and stock and municipal supplies in the upper Arkansas River basin is derived mostly from the Arkansas River and its tributaries. The flow regime of the river has been altered by increased reservoir capacities and importation of 69,200 acre-feet per year from the Colorado River drainage through transmountain diversions. An estimated 10.2 million acre-feet of hydrologically recoverable water is present in the first 200 feet of basin-fill alluvium. Well yields of 300 gallons per minute have been reported for the Dakota-Purgatoire aquifer aquifer located east of Canon City. Water quality of ground- and surface-water resources are generally acceptable for agriculture and stock watering, but concentrations of iron, manganese, sulfate, pH, and hardness may exceed recommended drinking-water criteria during periods of river low flow. Concentrations of mercury, selenium, and select radiochemical constituents also were high in the Dakota-Purgatoire aquifer. Dissolved solids increased downstream and in local areas as a result of water use and in the Leadville area because of mine drainage. (USGS)
Area 61 is located on the Colorado-New Mexico boundary in Huerfano and Las Animas Counties, Colorado, and Colfax County, New Mexico, and includes the Raton Mesa coal region. The 5 ,900-square-mile area is an asymmetrical structural trough bounded by the Rocky Mountains on the west and the Great Plains on the east. The area is drained by the Huerfano, Apishapa, Purgatoire, and Canadian Rivers (and their tributaries), all tributary to the Arkansas River. The principal coal-bearing formations are the Vermejo Formation of Late Cretaceous age and the Raton Formation of Late Cretaceous and Paleocene age. Much of the coal in the area is of coking quality, important to the metallurgical industry. Topographic relief in the area is greater than 8,700 feet, and this influences the climate which in turn affects the runoff pattern of area streams. Summer thunderstorms often result in flash floods. Virtually all geologic units in the region yield water. Depth to ground water ranges from land surface to 400 feet. Surface and ground water in the area contain mostly bicarbonate and sulfate ions; locally in the ground water, chloride ions predominate. Potential hydrologic problems associated with surface coal mining in the area are water-quality degradation, water-table decline, and increased erosion and sedimentation.
Area 61 is located on the Colorado-New Mexico boundary in Huerfano and Las Animas Counties, Colorado, and Colfax County, New Mexico, and includes the Raton Mesa coal region. The 5 ,900-square-mile area is an asymmetrical structural trough bounded by the Rocky Mountains on the west and the Great Plains on the east. The area is drained by the Huerfano, Apishapa, Purgatoire, and Canadian Rivers (and their tributaries), all tributary to the Arkansas River. The principal coal-bearing formations are the Vermejo Formation of Late Cretaceous age and the Raton Formation of Late Cretaceous and Paleocene age. Much of the coal in the area is of coking quality, important to the metallurgical industry. Topographic relief in the area is greater than 8,700 feet, and this influences the climate which in turn affects the runoff pattern of area streams. Summer thunderstorms often result in flash floods. Virtually all geologic units in the region yield water. Depth to ground water ranges from land surface to 400 feet. Surface and ground water in the area contain mostly bicarbonate and sulfate ions; locally in the ground water, chloride ions predominate. Potential hydrologic problems associated with surface coal mining in the area are water-quality degradation, water-table decline, and increased erosion and sedimentation. (USGS)
Selected hydrologic data collected in 1975-80 as part of water-quality investigations by the U.S. Geological Survey in Pueblo and southeastern Fremont Counties, Colo., are presented in this report. The data, in tabular form, consist of streamflow-discharge measurements for 33 sites, channel-geometry measurements for 97 sites, traveltime data for 12 sites, and field and laboratory water-quality analyses for 194 sites. Federal, state, and local officials may find these data useful in making decisions relating to the management of water resources of the area.
The waste-assimilation capacity of a 42-mile reach of the Arkansas River in Pueblo County, Colo., was evaluated using a one-dimensional steady-state water-quality model. The model was calibrated and verified using hydraulic and water-quality data collected in 1976 and 1979. The water-quality con-stituents modeled were 5-day carbonaceous biochemical oxygen demand, total organic nitrogen, total ammonia, total nitrite, total nitrate, and dissolved oxygen. Model calibration was acceptable for all constituents except total organic nitrogen, and verification was acceptable for all constituents except total organic nitrogen and total nitrite. A relationship between nonionized and total ammonia was defined to provide simulation capability for nonionized ammonia. The model was used to simulate the water-quality effects of 63 combinations of wastewater treatment. The water-quality effects were evaluated with respect to water-quality guidelines that may be applied based on possible stream-use classifications. Model simulations were based on a 7-day low flow with a 10-year recurrence interval that occurs between August 15 and October 15 and on a winter low-flow period that occurs as a result of upstream storage of water. The mixing zone downstream from the Pueblo Wastewater Treatment Plant outfall was evaluated to determine where the water-quality guidelines should apply for the model simulations. Complete lateral mixing of the effluent from the Pueblo Wastewater Treatment Plant occurred 2.7 river miles downstream from the outfall. Model simulations indicated a water-quality guideline of 0.06 milligram per liter nonionized ammonia nitrogen would be exceeded at the end of the mixing zone for Q7,10 conditions with secondary treatment at the Pueblo Wastewater Treatment Plant and a projected effluent discharge for the year 2000, and that a water-quality guideline of 0.5 milligram per liter total nitrite nitrogen would be exceeded for winter conditions and the same waste-water-treatment possibility. Wastewater-treatment possibilities with a pro-jected discharge for the year 2000 which would result in both water-quality guidelines being met include land application of treated effluent and advanced secondary treatment at the Pueblo Wastewater Treatment Plant with conversion of ammonia to nitrate to result in an effluent total ammonia nitrogen concentration of 5.4 to 10.6 milligrams per liter, depending on the quality of effluent from the downstream discharge from the CF&I Steel Corp. Model simulations also included an evaluation of flow augmentation necessary to meet a water-quality guideline of 0.06 milligram per liter non-ionized ammonia nitrogen. The evaluation was made for the n,7,10 period, secondary treatment at the Pueblo Wastewater Treatment Plant with a projected discharge for the year 2000, and effluent water quality at a downstream discharge which could contain twice the estimated ammonia concentration allowable for best available technology treatment for the iron and steel industry. The flow augmentation necessary to meet the water-quality guideline, based on the model simulations, is approximately 140 cubic feet per second.
Hydrologic data collected in 1975-77 as part of a comprehensive water-resources investigation of Boulder County, Colo., by the U.S. Geological Survey in cooperation with the Boulder County Health Department and the Colorado Geological Survey are presented in this report. The data, in tabular and graphic form, consist of water-quality analyses of selected constituents and geohydrologic-site, water-treatment, and sewage-treatment data for 609 wells and 48 springs; water-quality analyses for 102 of the wells and 9 of the springs; water-quality analyses of streamflow from 34 sites; and specific conductance and water-temperature measurements of streamflow from 3 sites. State and local officials in Boulder County may find these data useful in planning for residential, commercial, and industrial development. (Kosco-USGS)