Sensitivity of Ground Water to Contamination in Lawrence County, South Dakota

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Sensitivity of Ground Water to Contamination in Lawrence County, South Dakota

Growth in Lawrence County continues to increase both the demand and the potential for contamination of aquifers from agricultural, urban, suburban, commercial, and industrial land uses in Lawrence County. The U.S. Geological Survey, in cooperation with Lawrence County and the City of Spearfish, documented a study of sensitivity of ground water to contamination in Lawrence County in a Water-Resources Investigations Report (WRIR 00-4103). The report documents the method of analysis, limitations of the method, and results of the analysis.

The study area was subdivided into sensitivity units that describe areas with a group of relative ratings of hydrogeologic characteristics, which can be compared to evaluate the potential for ground water to be contaminated. Sensitivity units were designated and delineated by sequentially evaluating six hydrogeologic characteristics: aquifer media, unsaturated media, hydraulic conductivity, recharge rate, depth to water, and land-surface slope. Plate 1 in the report shows the areal distribution of these sensitivity units with identifying codes.

An additional mechanism of transport of potential contaminants is streamflow loss. Thus, the sensitivity of outcrops within loss zones also can be affected by conditions within drainage areas upstream from potential streamflow-loss zones. Drainage areas upstream from loss zones were delineated and described and are shown along with the associated loss zones on Plate 2 in the report.

Water-Resources Investigations Report 00-4103 can be ordered from:

USGS Information Services
Box 25286
Denver Federal Center
Denver, CO 80225-0046
Tel: 888-ASK-USGS; Fax 303-202-4693

Digital data sets were prepared that represent the spatial and attribute information shown on the two plates in the report. Metadata text files are attached to the digital data sets that document georeferencing information and the process steps used in creating the digital data sets.

Downloadable Digital Data representing Sensitivity of Ground Water to Contamination in Lawrence County, SD and associated metadata can be downloaded by clicking on links to archived data sets below.

sd_lcsens_pol - Polygons Representing Sensitivity of Ground Water to Contamination
sd_lcsens_da - Polygons Representing Drainage Areas Upstream from Potential Streamflow-loss Zones 
sd_lcsens_lz - Arcs Representing Potential Streamflow-loss Zones

Other downloadable U.S. Geological Survey digital data sets are available at this link to the archive list.