GROUND-WATER RESOURCES PROGRAM watergs/ogw/gwrp/

1. GROUND-WATER RESOURCES PROGRAMhttp://water.usgs.gov/ogw/gwrp/ IAEA/GEF IW Learn/USGS ExchangeApril 16, 2007Reston, VA

2. Ground water is the source of drinking water for about 50% of the US population, about 96% of water used for rural domestic supplies, and 40% of water used for public supplies Provides 42% of irrigation for Nation’s agriculture Sustains flow of most streams and rivers Maintains a variety of aquatic ecosystems Ground Water in US

3. Principal Aquifers Source: U.S. Geological Survey National Atlas of the United States; http://nationalatlas.gov/atlasftp.html

4. Mission To provide objective scientific information and develop interdisciplinary understanding to help assess and assure the availability of the Nation’s ground-water resources. GROUND-WATER RESOURCES PROGRAM

5. Ground-Water Resources Program RegionalGWEvaluations FieldMethods &Models Data Collection & Water-LevelMonitoring Other Priority GW Issues TechnicalSupport

6. Regional Ground-Water Evaluations GoalTo provide the Nation with an overview of the status and trends in water availability and improve ability to forecast availability for future uses. • How much water do we have? • How is water availability changing? • How does the availability of ground-water relate to demand, recharge, and geographic location?

7. Water budgets of major systems Current estimates and historic trends in ground-water storage, recharge, and discharge Ground-water models that provide Regional context for more local studies Tool to make future projections of water availability Products

8. Region-wide estimates of key hydrologic variables (e.g. aquifer properties, recharge, and withdrawals) for major aquifers. Evaluation of the existing network for monitoring ground-water availability Testing and evaluation of new approaches for analysis of regional aquifers Products (Cont.)

9. Current Regional Ground-Water Availability Studies Plan for National Ground-Water Availability Assessment Studies

10. Priority Ground-Water Issues • Aquifer Management • Aquifer Storage and Recovery • Ground-Water Recharge • GW/SW Interaction • Characterization of subsurface heterogeneity • Flow and transport in karst and fractured aquifers

11. Ground-Water Recharge in the Humid Areas of the US Mapping spatial and temporal variability

12. Southwest Project, Recharge Study Sites Trout Creek Amargosa River Sand Hollow Arroyo Honda Mojave River Abo Arroyo Rillito Creek

13. Field Methods and Models

14. Heat as a Tracer http://pubs.water.usgs.gov/circ1260/

15. Continuous measurement over kilometers Temporal resolution = ~1 min Meter-scale spatial resolution ~0.1 C thermal resolution 25 yr sensor life (in-place) Fiber Optic Sensing Technology

16. Waquoit Bay Study Area Boat house & control unit Fiber-Optic Grid • Additional temperature sensors (Hobos) attached for ground truth; seepage measurements; pore-fluid salinity measurements.

17. Time-Lapse DTS Data • Intermittent cold region near-shore (0-5 m) • Tidal influence diminishes with distance offshore • More stable temperatures beyond 30 or 40 m Low Tide Temp., deg C High Tide

18. MODFLOW Unsaturated-zone flow (UZF1) FARM process Local-grid refinement (LGR) GSFLOW SEAWAT SUTRA Recent Model Development

19. Simulates flow, storage, and ET in the unsaturated zone and recharge to the water table in response to infiltration at land surface Unsaturated-Zone Flow (UZF1) Package(Niswonger, Prudic, and Regan 2006)

20. Farm Process for MODFLOW(Schmid and others, 2006)

21. Local Grid Refinement(Mehl and Hill, 2006) Parent grid Child grid Interface

22. GSFLOW—A basin-scale model for simulation of coupled Ground-water and Surface-water FLOW Precipitation Snow accumulationsnowmelt and runoff Stream Infiltration

23. SEAWAT Documentation Biscayne Aquifer Analysis

24. SUTRA Simulated salinity near Hilton Head Island, South Carolina Documentation

25. Ground Water Model Development-- Applications Software • Web Sitehttp://water.usgs.gov/software/ground_water.html

26. USGS database (GWSI) contains more than 850,000 ground-water records. Annually about 20,000 wells are measured—periodic and continuous. Real-time data are available on about 1,000 wells during the most recent year. Data Collection and Ground-Water Level Monitoring Networks

27. Water-level changes in the High Plains aquifer, predevelopment to 2003. Source McGuire, 2004. No National Network!

28. USGS Ground-WaterClimate Response Network • Goal: Monitor effects of drought and other climate variability on ground-water levels. • Well selection criteria: • Open to a single, known hydrogeologic unit  • Known well construction  • Located in unconfined aquifers or near-surface confined aquifers that respond to climatic fluctuations  • Minimally affected by pumpage • Essentially unaffected by irrigation • Long-term accessibility  • Well has never gone dry

29. USGS Climate Response Network • In 2006, CRN consists of 554 wells (286 RT, 213 tape-down wells and 55 continuous recorders). • About 140 wells are totally supported with Federal funds (GWRP) and the remainder from cooperative arrangements. • In 2006, 51% of wells in network are instrumented for real-time data. • Each of the 50 States and Puerto Rico have at least one well in the network.

30. Current Climate Response Network

31. For More Information http://water.usgs.gov/ogw/gwrp/

32. THE END Contact Info: Kevin DennehyProgram Coordinator, Ground-Water Resources703-648-5018kdennehy@usgs.gov

33. Ground-Water Resources Program Studies2006