Geology topics

R.A. Darner

Publications and source records attributed to R.A. Darner.

4 recordsLinked to original sources

USGS2002

Lag times of bank filtration at a well field, Cincinnati, Ohio, USA

Wells placed next to surface-water bodies to induce infiltration have come under scrutiny because of the presence of the potential pathogens in surface water. Removal of pathogens and other contaminants by bank filtration is assumed, but regulatory agencies question the effectiveness of this process. To investigate transport processes of biological constituents, advective groundwater traveltimes to production wells under the influence of surface water need to be established first to determine appropriate water-quality sampling schedules. This paper presents the results of a study of bank filtration at a well field in southwestern Ohio. Field parameters such as water level, specific conductance, and water temperature were measured at least hourly at a streamflow gaging station and at five monitoring wells each at two separate sites, corresponding to two nearby production wells. Water-quality samples also were collected in all wells and the streamflow gaging station. Specific conductance is directly related to concentration of chloride, a chemically conservative constituent. Cross-correlation methods were used to determine the average traveltime from the river to the monitoring wells. Traveltimes based on specific conductance ranged from approximately 20 h to 10 days at one site and 5 days to 3 months at the other site. Calculated groundwater flow velocities ranged from 2.1 ?? 10-3 to 6.0 ?? 10-3 cm/s and 3.5 ?? 10-4 to 7.1 ?? 10-4 cm/s at the two sites. Data collected when a production well is continuously pumping reveal shorter and more consistent traveltimes than when the same well is pumped intermittently. ?? 2002 Elsevier Science B.V. All rights reserved.

Journal of Hydrology↗

USGS2000

Comparison of methods for determining Escherichia coli concentrations in recreational waters

Seventy water samples were collected from three Lake Erie beaches to compare recoveries of Escherichia coli (E. coli) using the USEPA-recommended method for recreational waters (mTEC) to recoveries using three alternative methods (MI, modified mTEC, and Colilert). Statistical tests showed no differences in recoveries of E. coli between MI and mTEC; however, statistically-significant differences were found between modified mTEC or Colilert and mTEC. The MI agar method provided the most similar assessment of recreational water quality to mTEC among the three alternative methods tested. The range of differences between Colilert and mTEC was widest among the three alternative methods. In a sample group with a range of values near the single-sample bathing-water standard, recoveries of E. coli were statistically lower using modified mTEC than mTEC; however, MI and Colilert compared well to mTEC in this range. Because samples were collected in a small geographic area, more work is necessary to test within-method variability of the modified mTEC, MI, and Colilert methods and to evaluate these methods as substitutes for the mTEC method in a variety of recreational waters. Copyright (C) 2000.

Water Research↗

USGS1999

Identification of potential wetlands in training areas on Ravenna Army Ammunition Plant, Ohio, and guidelines for their management

Potential wetlands in training areas on Ravenna Army Ammunition Plant, Ohio, were mapped by use of geographic information system (GIS) data layers and field inspection. The GIS data layers were compiled from existing sources and interpretation of aerial photography. Data layers used in the GIS analysis were wetland-plant communities, hydric soils, National Wetlands Inventory designated areas, and wet areas based on photogrammetry. According to review of these data layers, potential wetlands constitute almost one-third of the land in the training areas. A composite map of these four data layers was compiled for use during inspection of the training areas. Field inspection focused on the presence of hydrophytic vegetation and macroscopic evidences of wetland hydrology. Results of the field inspection were in general agreement with those predicted by the GIS analysis, except that some wet areas were more extensive than predicted because of high amounts of precipitation during critical periods of 1995 and 1996. Guidelines for managing wetlands in the training areas are presented.

Open-File Report↗

USGS1998

Descriptions of selected digital spatial data for Ravenna Army Ammunition Plant, Ohio

Digital spatial data of Ravenna Army Ammunition Plant (RVAAP), in northeastern Ohio, were compiled or generated from existing maps for U.S. Army Industrial Operations Command. The data are in the Ohio north state-plane coordinate system (North American Datum of 1983) in an ARC/INFO geographic information system format. The data comprise 15 layers, which include boundaries, topography, and natural and cultural features. An additional layer comprises scanned and rectified aerial photographs of RVAAP.

Open-File Report↗