CONSUMPTIVE-LOSS MITIGATION USING CONNECTOR WELLS AND ALLUVIAL DAMS

Pennsylvania has favorable precipitation, the highest stream density in the continental U.S., about 85,000 miles of waterways, and few flood control dams. A third of the rivers are so polluted to harm, wildlife propagation and recreation. Treatment costs discourage development.

It is feasible to acquire municipal groundwater supplies in sandstone aquifers along the crests and flanks of anticlines in close proximity to legacy, clay and bituminous coal mines without inducing AMD into public water supplies, depleting baseflows, wetlands and springs within high-quality watersheds selected for investigation.

Our Susquehanna River Basin Commission (SRBC), approved project will afford new mitigation options favoring less obtrusive development in high and exceptional quality watersheds. Stormwater will be diverted by gravity, spread and filtered within 15 to 31 feet of seasonally dewatered alluvium.

Applied water will be captured by connector wells screened in alluvium and open to semi-confined sandstone aquifers under lower hydraulic heads. Water not intercepted will be stored in alluvium behind cutoff walls allowing protracted release of colder water to enhance baseflows. Thicker occurrences of unsaturated alluvium and glacial outwash are widespread in PA as are unconfined and semi-confined aquifers with available storage potential. An infiltration gallery, water line and additional connector wells are planned pending positive results from this project and SRBC's storm-water recharge allocation. The determined number and efficiency of connector wells is dependent on precipitates from mixing reactions to be evaluated.

We have constructed connector wells to abate AMD from subsurface coal mines, neutralize atmospheric deposition within Linn Run, Laurel Highlands, PA, maximize well yields and to reduce thieving interferences.

Climate-induced thermal stresses will impact PA watersheds. Daily temperatures from 1895 thru 2017 have risen by + 0.132°F/Decade and precipitation by +0.267 in./Decade. Frequency and magnitude of flooding are predicted to be greater for smaller basins that lack flood control structures. With climate change and growing water demands connector wells and alluvial dams have the potential to mitigate consumptive loss while sustaining high and exceptional quality watersheds.