Description: Aquifer Pump Testing, Impact Analysis, Hydrogeologic Assessment Report for Property Rezoning, Long Term Monitoring Loudoun County, Virginia  2005-2008

Analytical Services, Inc. (ASI) personnel assisted our client, a large Virginia aggregate mining company, in meeting local County Ordinance requirements for rezoning of a 300 acre property for resource extraction (quarry operation). A workplan was prepared to identify suspect transmissive zones in the bedrock underlying the site, target potential high-yield well sites, oversee well installation, conduct aquifer testing to characterize aquifer parameters underlying the site, simulate dewatered conditions, and to determine the potential for off site impact.

Our workscope included a review of available geologic information, field reconnaissance to verify geologic mapping, fracture trace analysis of aerial photographs, and completion of geophysical surveys at select locations to determine the location of suspect transmissive zones within the bedrock aquifer underlying the site. Target locations for pumping wells and observation wells were staked in the field. Our staff oversaw drilling of the wells and prepared accurate well logs with the location of observed water bearing fractures and their respective blown yields.

Simultaneous 48-hour constant drawdown testing was completed on 5 “pumping” wells. During the Pump test, the groundwater level measurements were recorded with automated down well level loggers in 14 observation well locations. A detailed hydrogeologic report was prepared for the subject property that included an analysis of the potential for off site impact. ASI personnel represented the client on several occasions during meetings with the County Staff to discuss both the planned project approach and the findings of our hydrogeological report. The hydrogeologic assessment met the County’s criteria and the project’s rezoning application was approved. ASI designed and implemented a long term groundwater monitoring program at the site.