National Strategy for the Assessment of Water Availability and Use in the United States

Transcription

1 Philippine National Workshop Water Availability Enhancement (WAVE) Project March 1-4, 2011 National Strategy for the Assessment of Water Availability and Use in the United States Kevin F. Dennehy Reston, VA USA U.S. Department of the Interior U.S. Geological Survey

2 Does the United States have enough water? We do not know, however.

3 Scientific and Technical Challenges to Meet US Demands for Water Measure and account for the Nation s water resources Develop methods to understand existing water resources while using those supplies more efficiently Develop and improve predictive water management tools

4 What do we know about the Nation s water availability? Build on Previous Work

5 Previous national and regional evaluations have improved our knowledge, however repeated evaluations of the resource are needed: new information on water resources becomes available; new methods and technologies are developed; the places water is used, water demands, and the issues of concern change with time; and the systems change in response to development.

6 Goals for a National Assessment Clarify our understanding of water availability status and trends and improve our ability to forecast the balance between water supply and demand for future economic and environmental uses. Can t effectively manage what don t measure or understand

7 Status Trends Forecast Will there be sufficient freshwater resources in the future to sustain economic growth and quality of life in the United States?

8 Water Availability and Use: Great Lakes Basin Pilot Funded in 2005, five-year project Respond to Great Lakes Issues Develop methods for National Assessment Groundwater, surface water, water use Image from NOAA, Great Lakes Environmental Research Laboratory, AVHRR satellite imagery, 1995

9 What is Water Availability? Water Quantity Water Quality Infrastructure And Existing Water Use Water Availability Ecology, Recreation, and Instream Use Economic Factors Water Law And Regulations

10 To determine water availability need to know Quantify resource (supply) and Information about its use (demand).

11 Framework for a National Assessment Principal Aquifers Water Resources Regions Source: U.S. Geological Survey National Atlas of the United States;

12 Surface Water Analysis What are current streamflows and how have they changed over time? How will new withdrawals affect streamflow?

13 Surface Water Analysis Stream gage data not available everywhere Developed new method to estimate streamflow over time at any stream even where there is no stream gage

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15 Water Use in the Great Lakes How much water is withdrawn and how much water is used? How does water use vary in time and space? Future water availability depends on groundwater, surface water and current water use.

16 Public-supply withdrawals: 3,800 million gallons per day 17.7 million people Groundwater 12% Surface Water 88% Self-supply domestic withdrawals: 410 million gallons per day 5.2 million people Surface Water < 1% Groundwater 99%

17 Groundwater Availability How has development changed groundwater levels and availability? What are potential constraints limiting groundwater availability?

18 Groundwater Availability Groundwater divides move because of pumping

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20 Forecast

21 Detail Look at Approach/Tasks Taken to Assess the Groundwater Component of Water Availability

22 Organize Geospatial Data Library Relation and Flow of Information Source: Faunt, 2009

23 Compile Geospatial Data Sets and Metadata Diversity of Data Types and Categories Detail of One Data Type California s Central Valley Source: Faunt, 2009

24 Assemble 3-D Hydrogeologic Framework Floridan Aquifer System

25 Assemble 3-D Hydrogeologic Framework California s Central Valley aquifer system Based on 8,500 drillers logs Interpolated to one-mile spatial grid at 50 foot depth intervals Coarse near river channels Finer in low energy environments (Corcoran Clay) Source: Faunt, 2009

26 Development of Regional Groundwater Modeling Tool Groundwater modeling is useful for the evaluation of historic changes in water budgets and provides a tool to understand system response to stresses from future human and environmental uses.

27 Pre-development /Engineered Source: Faunt, 2009 Natural Simple 2 million acrefeet/year recharge /discharge Engineered Complex 12 million acrefeet/year recharge /discharge Source: Faunt, 2009

28 Spatial & Temporal Variability in Groundwater Budgets Source: Faunt, 2009 Source: Faunt, 2009

29 Trends in Water Budget Components Groundwater budgets change in response to human and environmental stresses (large-scale pumping and climate variability). Source: Alley and others, 2002 and Johnston, 1999

30 Cumulative Change in Storage Human Effects Climate Effects* Source: Faunt, 2009

31 Middle Claiborne aquifer (Sparta) Tool capable of forecasting system response How long will groundwater supplies last? Clarke and others, 2011

32 Products/Outcomes Water budgets of major aquifers systems Trends in groundwater use, storage, recharge, and discharge Groundwater models that provide Regional context for more local studies Tools to make future projections of groundwater availability Region-wide estimates of key hydrologic variables Assess climate variability effects on future groundwater availability Evaluation of existing networks for monitoring groundwater availability

33 Regional Design Flexibility Scaling Up -- Periodic National Synthesis/ National Assessment Scaling Down -- Regional to Local Scales Scale Area (mi 2 ) Cells per layer Cell size (ft) Regional x 5000 Intermediate x 500 Local x 72 Model Area 107,000 mi 2 277,000 km 2

34 Developing a Sound Approach for a National Assessment Characterize water resources at multiple spatial and temporal scales. Answer questions at scales that are relevant to local, State, tribal, and Federal decisions makers and provide the information and tools used to those stakeholders. Find effective means to deliver national-scale products/water information while recognizing that these same resources are commonly managed on a local scale.

35 Developing a Sound Approach for a National Assessment (cont.) Educate water-resource managers and the public to think of regional water resources in an integrated way. Incorporate understanding of how future changes to a system driven by human uses, climate variability, or landuse change may be accommodated by informed waterresources management.

36 For More Information Kevin Dennehy Program Coordinator