U.S. Department of the Interior U.S. Geological Survey Water Resources Jack Eggleston and Verne Schneider June 22-23, 2013 Groundwater Science Potential Activities in the Mountain Aquifer of the Eastern Basin

A Safe and Sustainable Groundwater Supply Depends on: Scientific understanding of ground water Water use planning and practices based on science Monitoring

Groundwater Science Approach Monitor – collect data to build a foundation Map – display the data Model – develop mass balance models to understand and predict groundwater processes Assess and Predict – understand how management policies will affect water resources Connect Science to Management - publish study results, present to regulators Continue Monitoring – to reassess and modify management practices

Examples of Groundwater Science in Other Stressed Aquifer Basins California Central Valley Middle Rio Grand Basin Columbia River Plateau

California Central Valley Semi-Arid – 300 mm/yr precip Population increasing, from population doubled Large groundwater withdrawals Water level declines and salinization are problems Water restrictions cause debate Complex management options Better understanding and tools were needed

California Central Valley- Groundwater Science Program Monitoring – Water levels Water use Water quality Land Use and Climate GIS Database Construction and Data Analysis Compartmentalized Model– Groundwater Surface Water Land Use Water Use and Management

Real-time Monitoring Online

California Central Valley – Groundwater Budget Outflow mostly to agricultural wells pumping Inflow mostly from recharge 1000’s of MCM

California Central Valley – Groundwater Model

California Central Valley Groundwater – Study Report Study is the basis for planning and regulation Model used as tool by regional water managers Monitoring continues to measure changing conditions and effects of management actions

Examples of Groundwater Science in Other Stressed Aquifer Basins California Central Valley Middle Rio Grand Basin Columbia River Plateau

Middle Rio Grand Basin Water use regulated by both state and federal agencies Groundwater is primary drinking water supply Semi-arid, 275 mm/yr precip Competition for scarce water Groundwater levels declining Better understanding needed for water supply planning

Middle Rio Grand Basin – Study Data compiled Natural tracers used to measure groundwater flowpaths and ages Existing MODFLOW models updated

Aquifer not being replenished as quickly as had been assumed Less ground water available in storage than previously believed Results provide basis for comprehensive local water policy Middle Rio Grand Basin – Study Results Public Reports:

Examples of Groundwater Science in Other Stressed Aquifer Basins California Central Valley Middle Rio Grand Basin Columbia River Plateau

U.S. Department of the Interior U.S. Geological Survey Water Resources Online Geologic Model

Geology is Known

Borehole Logs Used to Build 3D Geologic Model

Elevation surfaces generated to represent each hydrogeologic unit

Model provides 3D geology representation of layers and faults

Model is available online

Groundwater Science Approach Monitor – collect data to build a foundation Map – display the data Model – develop mass balance models to understand and predict groundwater processes Assess and Predict – understand how management policies will affect water resources Connect Science to Management - publish study results, present to regulators Continue Monitoring – to reassess and modify management practices

Applications to the Eastern Basin Monitor – Map – Model – Assess and Predict – Connect Science to Management - Continue Monitoring -