Stephen Kalkhoff (Former Employee)

A study was conducted during 1990 through an 11.2-km reach of Roberts Creek in northeastern Iowa to determine the fate of atrazine in a surface water environment Water samples were collected at ~1-month intervals from April through November during stable low to medium flow conditions and analyzed for atrazine and two of its initial biotic degradation products, desethylatrazine and

A hydrologic investigation to define the extent of brine contamination in ground water and streams in the Baxterville oil field area was conducted from October 1984 through November 1985. The 260-square-mile study area includes the Baxterville oil field (approximately 12.5 square miles) in southwestern Lamar and southeastern Marion Counties, Mississippi. Since 1944, disposal of more than...

A hydrologic investigation to determine vertical and seasonal variation of atrazine, alachlor, cyanazine, and nitrate at one location and to relate the variation to ground-water movement in the Iowa River alluvium was conducted in Iowa County, Iowa, from March 1986 to December 1987. Water samples were collected at discrete intervals through the alluvial sequence from the soil zone to the...

Time of travel and dispersion were determined in a 9.4-river-mile reach of Roberts Creek in northwestern Clayton County, Iowa, in the spring of 1990. Time of travel was determined so that a discrete parcel of water could be sampled through the study area during medium to low streamflow conditions. Dispersion characteristics were determined to identify solute-transport differences under...

Hydrologic data were collected in the Big Spring basin located in Clayton County, Iowa, during the 1990 water year. The data were collected by the U.S. Geological Survey in cooperation with the Iowa Department of Natural Resources, Geological Survey Bureau, to provide information on variation and movement of agricultural chemicals in the hydrologic cycle in the basin. Precipitation...

Hydrologic data were collected in the Big Spring Basin located in Clayton County, Iowa, during the 1989 water year. The data were collected in cooperation with the Iowa Department of Natural Resources, Geological Survey Bureau, to provide information on variation and movement of agricultural chemicals in the hydrologic cycle in the Big Spring Basin. Precipitation, stream, and ground...

No abstract available.

Hydrologic data was collected during the 1988 water year in cooperation with the Iowa Department of Natural Resources Geological Survey Bureau in the Big Spring ground-water basin located in Clayton County, Iowa. Information on precipitation, streams, and ground water was collected in the basin. Total rainfall at Big Spring was 24.08 inches. The greatest monthly rainfall was in September...

Intense development of the Miocene aquifer system for water supplies along the Mississippi Gulf Coast has resulted in large water level declines that have altered the groundwater flow pattern in the area. Water levels in some Miocene aquifers have declined about 2 ft/year since 1940; declines exceed 100 ft (80 ft sea level) in large areas along the coast. Water levels in the surficial...

The U.S. Geological Survey, in cooperation with the Mississippi Department of Natural Resources, Bureau of Geology, is conducting a hydrologic data collection program in potential lignite-producing areas in the outcrops of the Wilcox Group in Mississippi. During August 1985, hydrologic data were collected at a total of 15 stream sites in Benton, Lafayette, Marshall, and Union Counties...

A hydrologic investigation to define areas of brine contamination in shallow freshwater aquifers commonly used for streams that drain the Brookhaven Oil Field, was conducted from October 1983 to September 1984. The Brookhaven Oil Field covers approximately 15 sq mi in northwestern Lincoln County, Mississippi. Since 1943, disposal of approximately 544.2 million barrels of brine pumped...

No abstract available.