USGS - science for a changing world

USGS Groundwater Information

Groundwater Resources Program

*  Home *  Regional GW Studies *  GW & Environment * Methods & Modeling *  Publications *  Data & Information
 [Photo: Groundwater flowing out of well.]

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

Past listings...

USGS Groundwater Watch

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

 [Image: USGS active water level wells location map.]

Other Water Topics

*  Water Resources

*  Groundwater

*  Surface Water

*  Water Quality

*  Water Use

USGS in Your State

USGS Water Science Centers are located in each state.

 [Map: There is a USGS Water Science Center office in each State.] Washington Oregon California Idaho Nevada Montana Wyoming Utah Colorado Arizona New Mexico North Dakota South Dakota Nebraska Kansas Oklahoma Texas Minnesota Iowa Missouri Arkansas Louisiana Wisconsin Illinois Mississippi Michigan Indiana Ohio Kentucky Tennessee Alabama Pennsylvania West Virginia Georgia Florida Caribbean Alaska Hawaii and Pacific Islands New York Vermont New Hampshire Maine Massachusetts South Carolina North Carolina Rhode Island Virginia Connecticut New Jersey Maryland-Delaware-D.C.

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

Key Assumptions and Critical Issues

The recession-curve displacement method assumes streamflow recessions represent groundwater discharge originating as spatially diffuse recharge and that the timing of recharge coincides generally with peaks in streamflow. Recharge is assumed to cause an instantaneous, uniform rise in groundwater levels throughout the basin as illustrated, where q = the groundwater discharge per unit of stream length (one side); ho = instantaneous water-table rise; and a = the distance from the stream to the hydrologic divide.

Figure 1. – Example application of the recession-curve displacement method.
Definition sketch for Rorabaugh's equation (from Rorabaugh, 1964).

Snowmelt runoff, streamflow regulation, and release of water from wetlands or bank storage are sources of water other than groundwater discharge that could affect the shape of the recession curve and recharge estimates. It is incumbent on the user to evaluate how these sources could affect recharge estimates. Rutledge (2000 and 2004) provided guidance for evaluating the significance of many of the simplifying assumptions and sensitivity of the RORA model to key parameters.

Because of the simplifying assumptions inherent in the equations, Halford and Mayer (2000) warned that RORA may not provide reasonable estimates of recharge. They concluded that "When used alone, the recession-curve-displacement method and other hydrograph-separation techniques are poor tools for estimating groundwater discharge or recharge because the major assumptions of the methods are commonly and grossly violated." Sun (2004) stated that recharge estimates from RORA are too large compared to water-budget estimates and base-flow separation.

USGS Home Water Climate and Land Use Change Core Science Systems Ecosystems Energy and Minerals Environmental Health Natural Hazards

Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo logo U.S. Department of the Interior | U.S. Geological Survey
Page Contact Information: Contact the Groundwater Resources Program
Page Last Modified: Tuesday, 03-Jan-2017 20:46:33 EST