supplies over half of the drinking water in the United States supplies over 60% of the water used for irrigation in the United States

Transcription

1 Groundwater accounts for 96% of unfrozen freshwater globally...is the major source of water for over 2 billion people globally supplies roughly 45% of water for irrigation globally supplies over half of the drinking water in the United States supplies over 60% of the water used for irrigation in the United States is THE strategic water reserve in times of extreme drought However, groundwater withdrawals go unmonitored and unmanaged in most places around the world, including most states in the United States, and the lack of management is becoming apparent. This poses a considerable threat to our nation s water security

2 Groundwater the water stored under the ground in soils or rock layers called aquifers surface water groundwater

3 Estimating water storage changes from space The GRACE time-variable signal on land is dominated by changes in terrestrial water storage, i.e. GRACE monitors changes in all of the water stored on land, the change in total water storage (all of the snow, surface waters, soil moisture and groundwater), at monthly and longer timescales Given the extremely high precision of GRACE, the resulting errors are ~1.5 cm for monthly storage anomalies at the 150,000 km 2 scale (~2.25 km 3 ) Colorado River Basin, Changes in Total Water Storage ( )

4 Groundwater depletion in California s Central Valley, October, 2003-March, 2009 Central Valley (blue) River Basin boundary Central Valley Sacramento River Basin San Joaquin River Basin Tulare Lake Basin California s Central Valley Is one of the most productive agricultural regions in the world Produces more than 250 different crops worth $17 billion per year (2002), or 8% of the food produced in the U. S. by value Accounts for 1/6 of irrigated land in the U.S. Supplies 1/5 of the demand for groundwater in the U.S. Is the second most pumped aquifer in the U. S. Groundwater depletion and subisdence have been documented there for decades (e.g. Faunt, 2009)

5

6 Storage Anomaly (cu km) Change in Total Water Storage in the Sacramento-San Joquin River Basins from GRACE /15/03 10/15/04 10/15/05 10/15/06 10/15/07 10/15/08 10/15/09 10/15/10 10/15/11 10/15/12 10/15/13 Date

7 Storage Anomaly (cu km) Change in Total Water Storage in the Sacramento-San Joquin River Basins from GRACE /15/03 10/15/04 10/15/05 10/15/06 10/15/07 10/15/08 10/15/09 10/15/10 10/15/11 10/15/12 10/15/13 Date

8 GRACE Water storage deficits Thomas, Reager, Famiglietti, GRL 2014

9 Estimating groundwater storage changes with GRACE S Total = S Snow + S Surface Water + S Soil Moisture + S Groundwater S Groundwater S Total - S Snow - S Surface Water - S Soil Moisture surface water Remove this ( S snow + S Surface Water + S Soil Moisture ) S Total from S Total To isolate this ( S Groundwater )

10 Storage Anomaly (cu km) Storage Anomaly (cu km) Storage Anomaly (cu km) Storage Anomaly (cu km) Storage Anomaly (cu km) 30 Estimating groundwater storage changes with GRACE California s Central Valley, TWSA Total Water Storage SWE SWE /15/03 10/15/04 10/15/05 10/15/06 10/15/07 10/15/08 10/15/09 10/15/10 10/15/11 10/15/12 10/15/13 Date 60 SW 40 Surface Water /15/03 10/15/04 10/15/05 10/15/06 10/15/07 10/15/08 10/15/09 10/15/10 10/15/11 10/15/12 10/15/13 Date 60 SM 40 Soil Moisture /15/03 10/15/04 10/15/05 10/15/06 10/15/07 10/15/08 10/15/09 10/15/10 10/15/11 10/15/12 10/15/13 Date /15/03 10/15/04 10/15/05 10/15/06 10/15/07 10/15/08 10/15/09 10/15/10 10/15/11 10/15/12 10/15/13 Date Trend in total water storage from GRACE /15/03 10/15/04 10/15/05 10/15/06 10/15/07 10/15/08 10/15/09 10/15/10 10/15/11 10/15/12 10/15/13 Date

11 --- Percent SWP Allocation --- Percent CVP Allocation Central Valley groundwater depletion from GRACE( ) Surface water allocations and groundwater use are closely connected? UCCHM, 2014

12 Cumulative Groundwater Loss (km 3 ) Cumulative Groundwater Depletion in California s Central Valley from USGS and GRACE 10 8 USGS Year GRACE Wet Wet Variable to Wet Variable to Wet Variable to Wet Cumulative Groundwater Loss (MAF) -90 Variable to Dry Variable to Dry -73 Dry Dry Dry Dry -110 UCCHM,

13 end

14 U.S. Drought Monitor September 23, 2014 (Released Thursday, Sep. 25, 2014) Valid 8 a.m. EDT S L S S L L Drought Impact Types: Delineates dominant impacts Author: Richard Heim NCDC/NOAA L S L S S S S S L L L S S S = Short-Term, typically less than 6 months (e.g. agriculture, grasslands) L = Long-Term, typically greater than 6 months (e.g. hydrology, ecology) Intensity: D0 Abnormally Dry D1 Moderate Drought D2 Severe Drought D3 Extreme Drought D4 Exceptional Drought The Drought Monitor focuses on broadscale conditions. Local conditions may vary. See accompanying text summary for forecast statements.

15 GRACE-Based Shallow Groundwater Drought Indicator September 29, 2014 GRACE-Based Surface Soil Moisture Drought Indicator September 29, 2014 Wetness percentiles are relative to the period Cell Resolution 0.25 degrees Projection of this document is Lambert Azimuthal Equal Area Wetness percentiles are relative to the period The surface layer is defined as the top 2 centimeters of soil Cell Resolution 0.25 degrees Projection of this document is Lambert Azimuthal Equal Area

16 Estimating groundwater storage changes with GRACE Colorado River Basin ( ) Total water storage anomalies Accessible water storage anomalies GW SW Castle et al., 2014, in review

17 Estimating groundwater storage changes with GRACE Colorado River Basin ( ) Surface and ground Total water storage anomalies GW SW Castle et al., 2014

18 Trends in Freshwater Storage from GRACE, Famiglietti and Rodell, 2013

19 Famiglietti et al., 2011 ~3 km 3 /yr Voss et al., 2013 ~13 km 3 /yr Rodell et al., 2009 ~18 km 3 /yr Bourzac, 2013; after Rodell et al., 2009; Famiglietti et al. 2011; Voss et al., 2013

20 Trend in Total Water Storage from GRACE, mm/yr equivalent water height

21 Interannual Variations in Dry Season (Fall) Total Water Storage from GRACE mm equivalent water height

22 Water storage changes in the United States ( ) Trend map courtesy of Felix Landerer, NASA JPL

23 Western US