New in GWRP

• Regional Groundwater Studies
  • Ground-Water Availability in the United States
• Water Availability Pilot
  • Consumptive water use coefficients for Great Lakes Basin
• Groundwater & 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.

Selected Methods for Estimating Groundwater Recharge In Humid Regions

• Water Budget
  • Deep Percolation Model
  • HELP3 Model
• Unsaturated Zone Methods
  • Darcian Method
  • Zero-Tension Lysimeters
  • Zero-Flux Plane
• Groundwater Methods
  • Groundwater Modeling
  • Water-Table Fluctuations
• Streamflow Methods
  • Seepage Meters
  • Streamflow Gain/Loss Measurements (Seepage Run)
  • Recession-Curve Displacement Method
  • Watershed Models
• Tracer Methods
  • Chloride
  • Chlorofluorocarbons
  • Temperature
  • Tritium