Brian BenhamVirginia Tech Biological Systems Engineering

Virginia Master Well Owner Network Training

Wellhead Protection and Land Use Impacts on Groundwater Quality

Land use-related Contaminant Sources

Contaminant Source Proximity – How close is too close?

Be concerned about land uses and potential contaminate sources visible from home

In situations where groundwater travel-times are shorter, activities further away may impact water quality Fractured bedrock

Limestone geology (karst)

Gravel aquifers that transmit water easily

Septic System – Potential Contaminant Source

Water Supply Protection Starts at Home!Keep potentially

contaminating activities at least 50 feet or more from wellhead or spring box

50 ft minimum

X

Photo by Tom McCarty

In all things, moderation…

Karst Topography/Geology – SINKHOLESEspecially susceptible to land use-related contaminationProvide a direct connection to groundwater contamination

http://pubs.usgs.gov/circ/circ1139

Living on Karst, Cave Conservancy of the Virginias

Sinkhole Clean-up

Before

After clean-up

Bull Creek CaveLee County west of Jonesville

Courtesy Wil Orndorff VaDCR

Land use also affects water quantityDevelopment reduces infiltration

through compaction (yards) and by increasing impermeable surfaces (roads, sidewalks, driveways, roof tops). Resulting less groundwater recharge.

Over draft or “groundwater mining” occurs where more water is withdrawn than recharges. Increased pumping depth, lower well

yields – Texas Panhandle (agriculture)

Land surface subsidence – Houston

Salt water intrusion – Mid-Atlantic

Questions?

http://www.waterencyclopedia.com/