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

Manual Determination of K

The recession index can be determined by manual compilation of a master recession curve composed of numerous recession segments during periods when groundwater was the dominant component of flow for each streamflow-gaging station. An example of manual construction of a master recession curve is shown in the figure from Bevans (1986). The extrapolated base-flow recession on the semi-log plot defines a straight line that declines one log cycle in 32 days. Thus, recession index is 32 days for this watershed.

Determination of the slope of the base-flow recession curve (from Bevans, 1986).