Alan P. Hall | Geology Reports

USGS2000

Suspended sediment in the St. Francis River at St. Francis, Arkansas, 1986-95

Daily suspended-sediment concentrations were analyzed from the St. Francis River at St. Francis, Arkansas during 1986 through 1995. Suspended-sediment particle size distribution was measured in selected samples from 1978 through 1998. These data are used to assess changes in suspended-sediment concentrations and loads through time. Suspended-sediment concentrations were positively related to discharge. At higher flows, percent silt-clay was negatively related to discharge. Nonparametric trend analysis (Mann-Kendall test) of suspended-sediment concentration over the period of record indicated a slight decrease in concentration. Flow-adjusted residuals of suspended-sediment concentration also decreased slightly through the same period. No change was identified in annual suspended-sediment load or annual flow-weighted concentration. Continued monitorig of daily-suspended-sediment concentrations at this site and others, and similar data analysis at other sites where data are available will provide a better understanding of sediment transport withint the St. Francis River.

Open-File Report↗

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.

Open-File Report↗

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↗