Brian Benham Virginia 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

Photo by Tom McCarty In all things, moderation…

Karst Topography/Geology – SINKHOLES Especially susceptible to land use-related contamination Provide a direct connection to groundwater contamination Living on Karst, Cave Conservancy of the Virginias

Sinkhole Clean-up Before After clean-up Bull Creek Cave Lee County west of Jonesville Courtesy Wil Orndorff VaDCR

Land use also affects water quantity Development 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 Over draft or “groundwater mining” occurs where more water is withdrawn than recharges.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?