Geology topics
G. N. Paulachok
Publications and source records attributed to G. N. Paulachok.
Storm and flood of July 5, 1989, in northern New Castle County, Delaware
On July 5, 1989, intense rainfall from the remnants of Tropical Storm Allison caused severe flooding in northern New Castle County, Delaware. The flooding claimed three lives, and damage was estimated to be $5 million. Flood conditions were aggravated locally by rapid runoff from expansive urban areas. Record- breaking floods occurred on many streams in northern New Castle County. Peak discharges at three active, continuous-record streamflow-gaging stations, one active crest-stage station, and at two discontinued streamflow-gaging stations exceeded previously recorded maximums. Estimated recurrence intervals for peak flow at the three active, continuous-record streamflow stations exceeded 100 years. The U.S. Geological Survey conducted comprehensive post-flood surveys to determine peak water-surface elevations that occurred on affected streams and their tributaries during the flood of July 5, 1989. Detailed surveys were performed near bridge crossings to provide additional information on the extent and severity of the flooding and the effects of hydraulic constrictions on floodwaters.
Records of wells, exploratory boreholes, and ground-water quality, Atlantic County and vicinity, New Jersey
No abstract available.
Water resources of Oley Township, Berks County, Pennsylvania
Oley Township covers an area of 24 square miles, about half of which is underlain by highly permeable carbonate rocks. Nondomestic wells in these rocks typically have yields of 200 gallons per minute, and some wells yield more than 1,000 gallons per minute. Ground-water yield for Oley Township is about 0.5 million gallons per day per square mile. Thus, about 12 million gallons per day could be pumped from wells on a sustained basis. However, pumping this amount would adversely affect streamflow. A series of discharge measurements on Manatawny Creek in January 1983 showed that the creek was gaining approximately 12 cubic feet per second where it crosses the more- permeable carbonate rocks. Thus, the streams are directly connected to these aquifers. The northern and western parts of the township are mostly underlain by shale, quartzite, granite, gneiss, and carbonate rocks of low permeability, and some wells do not yield enough water for domestic supplies. A water-table map shows that two active quarries in low-permeability rocks have had little effect on the hydrologic system. Specific yields are about 4.5 percent for the carbonate rocks; 5 percent for quartzite, granite, and gneiss; 1 percent for the noncarbonate sedimentary rocks; and 1.5 percent for the Jacksonburg Limestone, which consists of argillaceous limestone. In 1982--a year of average precipitation--the ground-water contribution to total streamflow ranged from 56 to 88 percent. Basins with the highest percentage of carbonate rock contribute the largest amount of ground water to streamflow. Evapotranspiration averaged about 26 inches in 1982. Water loss was 32 inches in the Limekiln Creek basin; this suggests that about 6 inches of precipitation bypassed the Limekiln Creek gaging station as ground-water underflow. The most serious water-quality problems are excessive nitrate concentrations and bacterial contamination. Water from 3 of 19 wells in carbonate rocks had nitrate concentrations in excess of the U.S. Environmental Protection Agency maximum contaminant level of 10 milligrams per liter. Water from 5 of the 19 wells had fecal streptococci counts of more than 20 colonies per 100 milliliters. Although most agencies concerned with the protection of public health have not set limits for fecal streptococci, they are pathogenic, and their presence in drinking water is undesirable.