New in GWRP

• Regional Ground-Water Studies
  • Ground-Water Availability in the United States
• Water Availability Pilot
  • Consumptive water use coefficients for Great Lakes Basin
• Ground Water & the Environment
  • Ground-Water Recharge in Southwestern US
• Methods & Modeling
  • SEAWAT v4--Simulation of 3D variable-density ground--water flow and transport
• Data & Information
  • Water-Level changes in aquifers of the Atlantic Coastal Plain, predevelopment to 2000

USGS in Your State

USGS Water Science Centers are located in each state.

Methods for Estimating Ground-Water Recharge In Humid Regions

Recharge has been defined as the process of addition of water to the saturated zone. Because it is almost impossible to measure directly, recharge is usually estimated by indirect means. The accuracy of the indirect estimates is usually difficult to determine, so a common recommendation is that recharge should be estimated by the use of multiple methods and the results compared.

This site describes the application, data needs, strengths, and weaknesses of widely-used methods for estimating ground-water recharge that have general applicability in humid regions of the U.S. The site is designed to be a quick-reference or resource guide for selecting appropriate methods for estimating recharge in humid areas. Currently, the site provides a comparison of 15 methods. Three methods are described in detail -- Darcy method, water-table fluctuation method, and recession-curve displacement method.

• Methods
• Comparisons of Methods
• Software and Models
• References