Publications

Understanding the interaction of ground water and surface water is fundamental to solving many of the water resource problems facing the Nation. To facilitate efficient management of the Nation's water resources, a program of study and evaluation of the interaction of ground water and surface water is proposed that would emphasize intersite comparison between 24 environments throughout the Nation.

Contraction scour at the State Highway 14 bridge over Wolf Creek in south-central Iowa was caused by a large flood on September 14 and 15, 1992. The bridge is a 30.5-m, single-span steel structure supported by vertical-wall concrete abutments with wingwalls. Approximately 6 meters of scour resulted from the flood. The peak discharge was estimated by water-surface profile analysis to be 2,200 cubic

An investigation to determine the relation between stream water quality and geohydrology in the Roberts Creek watershed, Clayton County, Iowa, was conducted during selected base-flow periods in 1988-90. Discharge measurements were made and water samples collected for analyses of nutrients and selected herbicides in 19 subbasins along the main stem and tributaries of Roberts Creek. The areal extent

The transport and biological effects of dormant spray pesticides were examined in the San Francisco Estuary, California, by measuring dissolved- pesticide concentrations and estimating toxicity using bioassays at a series of sites in January and February 1993. Distinct pulses of pesticides, including diazinon, methidathion, and chlorpyrifos, were detected in the San Joaquin River in January and Fe

The record flood on the upper Mississippi River basin during the summer of 1993 provided a rare opportunity for collection of data on streambed scour at bridges and for testing of scour data collection equipment under extreme hydraulic conditions. Real-time scour measurements at bridges are categorized into one of three classes according to their objective: inspection measurements, limited-detail

The objective of this study was to investigate the occurrence of herbicide active and inactive ingredients (primarily volatile organic compounds) at four selected sites in Iowa representing drain tiles, observation wells, or lysimeters. Water samples were collected monthly and bi-monthly before and after herbicide applications in 1991, respectively. They were analyzed for seven herbicides and 32 v

The magnitude and frequency of the 1993 peak discharges in the upper Mississippi River Basin are characterized by applying Bulletin 17B and L-moment methods to annual peak discharges at 115 unregulated watersheds in the basin. The analysis indicated that the 1993 flood was primarily a 50-year or less event on unregulated watersheds less than about 50,000 km2 (20,000 mi2). Of the 115 stations analy

Mammoth Mountain, in the western United States, is a large dacitic volcano with a long history of volcanism that began 200 kyr ago and produced phreatic eruptions as recently as 500 ± 200 yr BP. Seismicity, ground deformation and changes in fumarole gas composition suggested an episode of shallow dyke intrusion in 1989–90. Areas of dying forest and incidents of near asphyxia in confined spaces, fi

The KTB pilot borehole in northeast Bavaria, Germany, penetrates 4000 m of gneiss, amphibolite, and subordinate calc-silicate, lamprophyre and metagabbro. There are three types of calcite in the drilled section: 1) metamorphic calcite in calc-silicate and marble; 2) crack-filling calcite in all lithologies; and 3) replacement calcite in altered minerals. Crack-filling and replacement calcite postd

The most common image of the interaction of groundwater and surface water is that of the interaction of streams with a contiguous alluvial aquifer. This type of system has been the focus of study for more than 100 years, from the work of Boussinesq (1877) to the present, and stream-aquifer interaction continues to be the most common topic of papers discussing the interaction of groundwater and sur

No abstract available.

A method has been developed to measure nanogram per liter amounts of selected volatile organic compounds (VOCs) including dichlorodifluoromethane, trichlorofluoromethane, cis-1,2-dichloroethene, trichloroethene, tetrachloroethene, and the isomers of dichlorobenzene in water. The method uses purge-and-trap techniques on a 100 mL sample, gas chromatography with a megabore capillary column, and elect