USGS Science⌕ Search

Geology topics

G.M. Ferrell

Publications and source records attributed to G.M. Ferrell.

7 recordsLinked to original sources
USGS2011

A study of the effects of implementing agricultural best management practices and in-stream restoration on suspended sediment, stream habitat, and benthic macroinvertebrates at three stream sites in Surry County, North Carolina, 2004-2007-Lessons learned

The effects of agricultural best management practices and in-stream restoration on suspended-sediment concentrations, stream habitat, and benthic macroinvertebrate assemblages were examined in a comparative study of three small, rural stream basins in the Piedmont and Blue Ridge Physiographic Provinces of North Carolina and Virginia between 2004 and 2007. The study was designed to assess changes in stream quality associated with stream-improvement efforts at two sites in comparison to a control site (Hogan Creek), for which no improvements were planned. In the drainage basin of one of the stream-improvement sites (Bull Creek), several agricultural best management practices, primarily designed to limit cattle access to streams, were implemented during this study. In the drainage basin of the second stream-improvement site (Pauls Creek), a 1,600-foot reach of the stream channel was restored and several agricultural best management practices were implemented. Streamflow conditions in the vicinity of the study area were similar to or less than the long-term annual mean streamflows during the study. Precipitation during the study period also was less than normal, and the geographic distribution of precipitation indicated drier conditions in the southern part of the study area than in the northern part. Dry conditions during much of the study limited opportunities for acquiring high-flow sediment samples and streamflow measurements. Suspended-sediment yields for the three basins were compared to yield estimates for streams in the southeastern United States. Concentrations of suspended sediment and nutrients in samples from Bull Creek, the site where best management practices were implemented, were high compared to the other two sites. No statistically significant change in suspended-sediment concentrations occurred at the Bull Creek site following implementation of best management practices. However, data collected before and after channel stabilization at the Pauls Creek site indicated a statistically significant (p<0.05) decrease in suspended-sediment discharge following in-stream restoration. Stream habitat characteristics were similar at the Bull Creek and Hogan Creek reaches. However, the Pauls Creek reach was distinguished from the other two sites by a lack of pools, greater bankfull widths, greater streamflow and velocity, and larger basin size. Historical changes in the stream channel in the vicinity of the Pauls Creek streamgage are evident in aerial photographs dating from 1936 to 2005 and could have contributed to stream-channel instability. The duration of this study likely was inadequate for detecting changes in stream habitat characteristics. Benthic macroinvertebrate assemblages differed by site and changed during the course of the study. Bull Creek, the best management practices site, stood out as the site having the poorest overall conditions and the greatest improvement in benthic macroinvertebrate communities during the study period. Richness and diversity metrics indicated that benthic macroinvertebrate community conditions at the Hogan Creek and Pauls Creek sites declined during the study, although the status was excellent based on the North Carolina Index of Biotic Integrity. Experiences encountered during this study exemplify the difficulties of attempting to assess the short-term effects of stream-improvement efforts on a watershed scale and, in particular, the difficulty of finding similar basins for a comparative study. Data interpretation was complicated by dry climatic conditions and unanticipated land disturbances that occurred during the study in each of the three study basins. For example, agricultural best management practices were implemented in the drainage basin of the control site prior to and during the study. An impoundment on Bull Creek upstream from the streamgaging station probably influenced water-quality conditions and streamflow. Road construction in the vicinity of the Pauls Creek site potentially masked changes related to stream-improvement efforts. In addition, stream-improvement activities occurred in each of the three study basins over a period of several years prior to and during the study so that there were no discrete before and after periods available for meaningful comparisons. Historical and current land-use activities in each of the three study basins likely affected observed stream conditions. The duration of this study probably was insufficient to detect changes associated with agricultural best management practices and stream-channel restoration.

North Carolina↗
USGS2009

Occurrence of Selected Pharmaceutical and Organic Wastewater Compounds in Effluent and Water Samples from Municipal Wastewater and Drinking-Water Treatment Facilities in the Tar and Cape Fear River Basins, North Carolina, 2003-2005

Samples of treated effluent and treated and untreated water were collected at 20 municipal wastewater and drinkingwater treatment facilities in the Tar and Cape Fear River basins of North Carolina during 2003 and 2005. The samples were analyzed for a variety of prescription and nonprescription pharmaceutical compounds and a suite of organic compounds considered indicative of wastewater. Concentrations of these compounds generally were less than or near the detection limits of the analytical methods used during this investigation. None of these compounds were detected at concentrations that exceeded drinking-water standards established by the U.S. Environmental Protection Agency. Bromoform, a disinfection byproduct, was the only compound detected at a concentration that exceeded regulatory guidelines. The concentration of bromoform in one finished drinking-water sample, 26 micrograms per liter, exceeded North Carolina water-quality criteria. Drinking-water treatment practices were effective at removing many of the compounds detected in untreated water. Disinfection processes used in wastewater treatment - chlorination or irradiation with ultraviolet light - did not seem to substantially degrade the organic compounds evaluated during this study.

North Carolina↗
USGS2007

Evaluation of tandem offline and online solid-phase extraction with liquid chromatography/electrospray ionization-mass spectrometry for the analysis of antibiotics in ambient water and comparision to an independent method

This report describes the performance of an offline tandem solid-phase extraction (SPE) method and an online SPE method that use liquid chromatography/mass spectrometry for the analysis of 23 and 35 antibiotics, respectively, as used in several water-quality surveys conducted since 1999. In the offline tandem SPE method, normalized concentrations for the quinolone, macrolide, and sulfonamide antibiotics in spiked environmental samples averaged from 81 to 139 percent of the expected spiked concentrations. A modified standard-addition technique was developed to improve the quantitation of the tetracycline antibiotics, which had 'apparent' concentrations that ranged from 185 to 1,200 percent of their expected spiked concentrations in matrix-spiked samples. In the online SPE method, normalized concentrations for the quinolone, macrolide, sulfonamide, and tetracycline antibiotics in matrix-spiked samples averaged from 51 to 142 percent of their expected spiked concentrations, and the beta-lactam antibiotics in matrix-spiked samples averaged from 22 to 76 percent of their expected spiked concentration. Comparison of 44 samples analyzed by both the offline tandem SPE and online SPE methods showed 50 to 100 percent agreement in sample detection for overlapping analytes and 68 to 100 percent agreement in a presence-absence comparison for all analytes. The offline tandem and online SPE methods were compared to an independent method that contains two overlapping antibiotic compounds, sulfamethoxazole and trimethoprim, for 96 and 44 environmental samples, respectively. The offline tandem SPE showed 86 and 92 percent agreement in sample detection and 96 and 98 percent agreement in a presence-absence comparison for sulfamethoxazole and trimethoprim, respectively. The online SPE method showed 57 and 56 percent agreement in sample detection and 72 and 91 percent agreement in presence-absence comparison for sulfamethoxazole and trimethoprim, respectively. A linear regression with an R2 of 0.91 was obtained for trimethoprim concentrations, and an R2 of 0.35 was obtained for sulfamethoxazole concentrations determined from samples analyzed by the offline tandem SPE and online SPE methods. Linear regressions of trimethoprim and sulfamethoxazole concentrations determined from samples analyzed by the offline tandem SPE method and the independent M3 pharmaceutical method yielded R2 of 0.95 and 0.87, respectively. Regressed comparison of the offline tandem SPE method to the online SPE and M3 methods showed that the online SPE method gave higher concentrations for sulfamethoxazole and trimethoprim than were obtained from the offline tandem SPE or M3 methods.

Scientific Investigations Report↗
USGS1995

Water-quality conditions at selected landfills in Mecklenburg County, North Carolina, 1986-92

Water-quality conditions at five municipal landfills in Mecklenburg County, North Carolina, were studied during 1986-92. Analytical results of water samples from monitoring wells and streams at and near the landfills were used to evaluate effects of leachate on surface and ground water. Ground-water levels at monitoring wells were used to determine directions of ground-water flow at the landfills. Data from previous studies were used for analysis of temporal trends in selected water-quality properties and chemical constituents. Effects of leachate, such as large biochemical- and chemical-oxygen demands, generally were evident in small streams originating within the landfills, whereas effects of leachate generally were not evident in most of the larger streams. In larger streams, surface-water quality upstream and downstream from most of the landfills was similar. However, the chemical quality of water in Irwin Creek appears to have been affected by the Statesville Road landfill. Concentrations of several constituents indicative of leachate were larger in samples collected from Irwin Creek downstream from the Statesville Road landfill than in samples collected from Irwin Creek upstream from the landfill. The effect of leachate on ground-water quality generally was largest in water from wells adjacent to waste-disposal cells. Concentrations of most constituents considered indicative of leachate generally were smaller with increasing distance from waste-disposal cells. Water samples from offsite wells generally indicated no effect or very small effects of leachate. Action levels designated by the Mecklenburg County Engineering Department and maximum contaminant levels established by the U.S. Environmental Protection Agency were exceeded in some samples from the landfills. Ground-water samples exceeded action levels and maximum contaminant levels more commonly than surface-water samples. Iron and manganese were the constituents that most commonly exceeded action levels in water samples from the landfills. Synthetic organic compounds were detected more commonly and in larger concentrations in ground-water samples than in surface-water samples. Concentrations of synthetic organic compounds detected in water samples from monitoring sites at the landfills generally were much less than maximum contaminant levels. However, concentrations of some chlorinated organic compounds exceeded maximum contaminant levels in samples from several monitoring wells at the Harrisburg Road and York Road landfills. Trend analysis indicated statistically significant temporal changes in concentrations of selected water-quality constituents and properties at some of the monitoring sites. Trends detected for the Holbrooks Road and Statesville Road landfills generally indicated an improvement in water quality and a decrease in effects of leachate at most monitoring sites at these landfills from 1979 to 1992. Water-quality trends detected for monitoring sites at the Harrisburg Road and York Road landfills, the largest landfills in the study, differed in magnitude and direction. Upward trends generally were detected for sites near recently closed waste-disposal cells, whereas downward trends generally were detected for sites near older waste-disposal cells. Temporal trends in water quality generally reflected changes in degradation processes associated with the aging of landfill wastes.

North Carolina↗
USGS1990

Water resources data, West Virginia, water year 1989

Water-resources data for the 1989 water year for West Virginia consist of records of stage, discharge, and water quality of streams; contents of reservoirs; and water levels of observation wells. This report contains discharge records for 81 streamflow-gaging stations; stage only records for 7 gaging stations; annual maximum discharge at 2 crest-stage partial-record stations; change in contents for 1 reservoir; water-quality records for 14 streamflow-gaging stations; and water-level records for 31 observation wells. Locations of these sites are shown on figures 4 and 5. Additional water data were collected at various sites, not involved in the systematic data collection program, and are published as miscellaneous measurements. These data represent that part of the National Water Data System collected by the U.S. Geological Survey and cooperating State and Federal agencies in West Virginia.

West Virginia↗
USGS1989

Water resources data for West Virginia, water year 1987

Water-resources data for the 1987 water year for West Virginia consist of records of stage, discharge, and water quality of streams; contents of reservoirs; and water levels of observation wells. This report contains discharge records for 83 streamflow-gaging stations; stage only records for 7 gaging stations, and 2 crest-stage partial-record stations; (2) contents for 1 reservoir, and change in contents for 1 reservoir; (3) water-quality records for 20 streamflow-gaging stations; and (4) water-level records for 34 observation wells. Locations of these sites are shown on figures 4 and 5. Additional water data were collected at various sites, not involved in the systematic data collection program, and are published as miscellaneous measurements. These data represent that part of the National Water Data System collected by the U.S. Geological Survey and cooperating State and Federal agencies in West Virginia.

West Virginia↗