Why is Groundwater Important? Drinking water for nearly 50% of US 98% of rural domestic supplies 35% of public supplies 42% of irrigation for agriculture Sustains flow of streams and rivers Maintains aquatic ecosystems

What Is Groundwater?

Contribution to Streamflow 54 Streams Range 14-90% Average 52% Geology Physiography Climate Runoff GW

Groundwater and Drought 6

Groundwater and Drought: Statewide Monitoring

Groundwater and Drought: Increased Pumping

Why Measure Water Levels? “You can’t manage what you don’t measure” Water level in a well is an indirect measure of the amount of water in the aquifer. Principal source of information on the hydrologic stress on the aquifer Provides the data necessary to –evaluate changes in the resource over time –develop models and forecast trends, and –design, implement, and monitor the effectiveness of groundwater management programs

Groundwater Networks

Existing Nationwide Coverage

GWRP Regional GW Availability Quantify current groundwater resources Evaluate how these resources have changed over time Provide tools to forecast system responses to stresses from future human and environmental uses. 11

Regional Groundwater Availability Studies Principal Aquifers of the US Selected Priority Aquifers

Ongoing or Completed Regional Studies