Maryland Department of Natural Resources

MGS presented research at the 2019 Maryland Water Monitoring Council Annual Conference, December 6, 2019

Changes in Groundwater and Surface Water in the Maryland Piedmont as a Result of Road-Deicing Salt Application

Tiffany VanDerwerker


Road-deicing salt has been applied to roads during winter storm events since the 1940’s. As a result, chloride concentrations in Maryland streams and groundwater have increased over time. In the Maryland Piedmont, unconfined aquifers are the primary water source for people on private water wells, and these aquifers are very susceptible to surface-based contamination. Water with elevated chloride concentrations can damage plumbing fixtures, appliances, and pipes. Chloride is unreactive and therefore it does not degrade in the environment and is easily mobilized in groundwater and surface water. Chloride transport between surface water and groundwater in Maryland has not been adequately evaluated. To investigate this relationship, the Maryland Geological Survey (MGS) performed a review of the literature for road-deicing salt impacts to both groundwater and surface water. As part of a multi-year study (conducted by MGS) to evaluate road-deicing salt contamination in groundwater, chloride data were compiled from various sources. These data were mapped in ArcGIS to evaluate spatial distribution of available data and changes in chloride concentrations over time.

Why Does Maryland Need a Regional Groundwater-Flow Model?

Dr. Emelia Furlong


The Maryland Geological Survey has developed numerical groundwater-flow models to assist local and county governments with estimating the water-supply potential of aquifers in Maryland’s coastal plain, mapping areas contributing recharge to wells, and monitoring saltwater intrusion. However, an up-to-date and comprehensive groundwater-flow model of the entire coastal plain aquifer system is needed to assess the cumulative effects of withdrawals across the region. Such a model was envisioned as part of a science plan developed to address the recommendations of the Advisory Committee on the State’s water resources (Wolman Commission). Groundwater resource managers need more comprehensive, robust, and interactive tools than are currently available to assess overall sustainability of groundwater resources. Water managers and planners also need to understand where and when groundwater withdrawals might reduce streamflow (baseflow), induce changes in groundwater quality (saltwater intrusion), or create other issues (well interference, excessive pumping levels, land subsidence) that could constrain the use of water. A regional groundwater-flow model that is accessible, regularly updated and calibrated could assist water resource planners to better insure a sustainable future for our critical groundwater resource and to address potential impacts of climate change.