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Geology topics

Kim L. Wetzel

Publications and source records attributed to Kim L. Wetzel.

4 recordsLinked to original sources
USGS1995

Land use, organochlorine compound concentrations, and trends in benthic-invertebrate communities in selected stream basins in Chester County, Pennsylvania

Land use was analyzed for the drainage areas of 26 stream sites in Chester County, Pa., that cover a total area of 227 square miles or about 30 percent of the country. The most significant land-use changes during 1967-87 were decreased agricultural land use, increased residential land use, and increased commercial and industrial land use. Bulk samples of stream-bottom materials were collected at 42 sites in the study area from October 1985 through November 1987 and analyzed for content of organochlorine pesticides and polychlorinated biphenyls (PCB's). Organochlorine compounds and (or) PCB's were detected in streambed materials collected at 40 of the 42 sites sampled. The most enriched compounds (greater than 15 micrograms per kilogram) were PCB's, chlordane, and DDT plus its breakdown products. Data suggest that chlordane residues are closely associated with residential land use. PCB residues are closely associated with industrial and commercial land use. Cores of labeled sediments from the site of Icedale Lake, a drained reservoir on the West Branch Brandywine Creek, indicate that DDT was the first organochlorine pesticide to enter the Brandywine Creek; concentrations peaked in the late 1940's and early 1950's. As DDT influx subsequently decreased, influxes of chlordane and dieldrin increased and peaked in the mind-1960's, before the Chester County biological monitoring program. Influx of all pesticides appears to have decreased significantly since the 1960's. Contingency analyses showed that the relation between the Kendall slope estimator for trend and the increases in residential land use of 12 percent or greater were significant at the 95-percent confidence level. The contingency tables also showed that the relation between diversity indices of less than 2.25 and organochlorine-compound concentrations greater than 45 micrograms per kilogram was significant at the 95-percent confidence level.

Water-Resources Investigations Report↗
USGS1986

Techniques for estimating streamflow characteristics in the Eastern and Interior coal provinces of the United States

Techniques are presented for estimating various streamflow characteristics, such as peak flows, mean monthly and annual flows, flow durations, and flow volumes, at ungaged sites on unregulated streams in the Eastern Coal region. Streamflow data and basin characteristics for 629 gaging stations were used to develop multiple-linear-regression equations. Separate equations were developed for the Eastern and Interior Coal Provinces. Drainage area is an independent variable common to all equations. Other variables needed, depending on the streamflow characteristic, are mean annual precipitation, mean basin elevation, main channel length, basin storage, main channel slope, and forest cover. A ratio of the observed 50- to 90-percent flow durations was used in the development of relations to estimate low-flow frequencies in the Eastern Coal Province. Relations to estimate low flows in the Interior Coal Province are not presented because the standard errors were greater than 0.7500 log units and were considered to be of poor reliability.

Water Supply Paper↗
USGS1982

Sedimentation in the East Branch Mahoning Creek basin, Clearfield and Jefferson Counties, Pennsylvania, June 1979 to June 1980

Parts of the East Branch Mahoning Creek basin, a forested area of 29.6 square miles in west-central Pennsylvania, are disturbed by farming, surface mining, unpaved haul roads, eroding reclaimed areas, and logging. Streamflow was measured and water samples collected at a site upstream from the mouth from June 1979 to June 1980 during base flow and storm periods to evaluate sediment discharges. An additional site on a tributary draining mostly farmland was sampled from December 1979 to June 1980. Samples were analyzed for suspended sediment, turbidity, and specific conductance. Daily mean suspended-sediment concentrations and discharges were computed. From June 1979 to June 1980, 3,570 tons of suspended sediment was transported from the basin. This was an average yield of 121 tons per square mile per year. From December 1979 to June 1980, a tributary draining 2.21 square miles of a predominantly agricultural area discharged 328 tons of sediment which was 12 percent of the sediment load transported from the entire basin. Monthly sediment discharges averaged 298 tons ranged from 32 tons in July to 1,250 tons in March. The highest daily mean suspended-sediment concentration was 712 milligrams per liter on June 8, 1980. On that date, 267 tons of sediment was discharged from the basin.

Pennsylvania↗