New & Noteworthy

Press Release: Study Explores Groundwater and Geothermal Energy in Drought-Stricken Eastern Oregon and Neighboring States

Technical Announcement: USGS Issues Revised Framework for Hydrogeology of Floridan Aquifer

Press Release: High Plains Aquifer Groundwater Levels Continue to Decline

Regional Groundwater Availability Study Geospatial Data

Press Release: USGS Assesses Current Groundwater-Quality Conditions in the Williston Basin Oil Production Area

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USGS Groundwater Watch

USGS maintains a network of active wells to provide basic statistics about groundwater levels.

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Recession-Curve Displacement Method for Estimating Groundwater Recharge In Humid Regions

Groundwater Evapotranspiration

"Because the RORA program is based on the assumption that the entire groundwater discharge hydrograph is described by Rorabaugh’s instantaneous-recharge model, the program does not explicitly allow for the effects of groundwater evapotranspiration (GWET)" (Rutledge 2000).

Tests by Rutledge show that RORA calculates net recharge (actual recharge minus loss to GWET) during periods of GWET. If the positive recharge is small during a period of GWET, then RORA can compute absurd recharge, values of less than zero.

This finding was important, because the initial usage of the method indicated that the results should be interpreted as recharge that was not affected by losses to evapotranspiration from the groundwater system. Instead, results should be characterized as net recharge.