Patrick Edelmann — Page 2

USGS1983

Hydrology of Area 61, Northern Great Plains and Rocky Mountain Coal Provinces, Colorado and New Mexico

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)

Water-Resources Investigations Report↗

USGS1980

Selected hydrologic data, Arkansas River basin, Pueblo and southeastern Fremont Counties, Colorado, 1975-80

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.

Colorado↗

USGS1980

Waste-assimilation capacity of the Arkansas River in Pueblo County, Colorado, as it relates to water-quality guidelines and stream classification

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.

Colorado↗