https://water.usgs.gov/ogw/gwrp/saltwater/salt.html
USGS Ground-Water Resources Program (GWRP): Freshwater-Saltwater Interactions along the Atlantic...
USGS - Freshwater-Saltwater Interactions along the Atlantic Coast; U.S. Geological Survey Ground-Water Resources Program
ground water
https://water.usgs.gov/ogw/gwrp/methods/wtf/fracrock_pa.html
USGS GWRP: Techniques/Methods -Water-Table Fluctuation (WTF) Method
USGS - Recharge to a Fractured Bedrock Aquifer in Pennsylvania - Water-Table Fluctuation (WTF) Method for Estimating Ground-Water Recharge In Humid Regions;...
water tableusgstechniquesmethodsfluctuation