GRACE Guru: Groundwater's Going...Going...

The GRACE Guru himself, Jay Famiglietti, sent me the figure below from a recent paper [J. S. Famiglietti and M. Rodell, Water in the Balance, Science, 340, 1300 (2013)] showing changes in water storage in various parts of the USA. As far as groundwater goes, it's not a pretty picture.

Here is the UCI-UHCCM press release:

Download UCCHM Press Release 1

The photo: View this photo 

The paper: Download Water in the Balance_SciencePerspectives_2013

Here is a story from Science Daily.

Jay and his co-author Matthew Rodell make the point that the GRACE data are critical to monitoring and managing regional (> 200,000 square kilometers or 80,000 square miles) water resource systems, including aquifer systems. Future GRACE missions should be developed to increase apatial resolution to about 50,000 square kilometers (20,000 square miles) and temporal resolution from monthly to weekly or biweekly.

From the Science Daily article [emboldening mine]:

"GRACE data provide new insights into regions in the U.S. and around the world where water issues have already approached the crisis stage. Their potential for game-changing contributions to regional water management is just beginning to be realized," says Famiglietti, who believes that maps like his and Rodell's make a strong case for immediate action, and ultimately, for a comprehensive, national water policy in the United States.

Love that last statement! A US national water policy? Maybe...just maybe....Nahhh!!!

The GRACE data are really something, As Jay, others, and I have noted, it is a game changer with regard to water management and also transnational water issues - the whole conflict issue.

I do have one concern with the enthusiasm over GRACE: people - some water managers, policymakers and decisionmakers - might begin to think that all we need are the GRACE data and no longer will have to collect information on groundwater levels, streamflow (stream gaging), soil moisture, ('ground-truthing') etc. I can hear them [legislators?] now: 'Think of all the money we can save!' Nothing could be further from the truth, especially with respect to groundwater. We need to collect groundwater-level data and monitor groundwater withdrawals; in fact, we need to expand both activities. We also need to assess how much groundwater we have. GRACE data cannot do this; they can only inform us of changes in the amount of groundwater stored.

I know of no substitute for good old-fashioned hydraulic head data to calibrate and validate groundwater management models. GRACE data can help in the modeling process, but as of now, and the foreseeable future, GRACE cannot do it all. It's another tool - albeit a highly sophisticated one - in the toolbox. I know Jay knows this. 

Both Jay and I will be panelists at the upcoming groundwater event at the University of Toronto's Munk School of Global Affairs, Underground Intelligence: The need to map, monitor, and manage Canada’s groundwater resources in an era of drought and climate change, on 25 June 2013: 

Download POWI-GroundwaterAgenda-June10

Should be fun; Zetland will be there, too.

Figure Caption: Groundwater storage trends around the United States as measured by the NASA/German Aerospace Center Gravity Recovery and Climate Experiment (GRACE) satellites between 2003 and 2012. GRACE data show water losses in major U.S. agricultural regions such as (1) California’s Central Valley (-1.5 ± 0.1 centimeters, or -0.59 ± 0.04 inches, per year) and (2) the Southern High Plains Aquifer (-2.5 ± 0.2 centimeters, or -0.98 ± 0.08 inches, per year), caused by overreliance on groundwater to supply irrigation water. Regions where groundwater is being depleted as a result of prolonged drought include (3) Houston (-2.3 ± 0.6 centimeters, or -0.9 inches, per year), (4) Alabama (-2.1 ± 0.8 centimeters, or -0.83 inches, per year) and (5) the Mid-Atlantic (-1.8 ± 0.6 centimeters, or -0.71 inches, per year). Water storage is increasing in (6), the flood-prone Upper Missouri River basin (2.5 ± 0.2 centimeters, or 0.98 inches, per year).

 The graphs surrounding the main image are monthly time series of GRACE-derived anomalies of total water storage (in centimeter-equivalent water height) for the points annotated (1) – (6). Monthly data are displayed as darker blue lines. Trend lines (in centimeters per year), in red, have been added to each time series plot. Monthly errors are shown as light blue shading..

 Data from University of Texas CSR Release-05 and prepared by Caroline de Linage, UC Irvine.

 From J. S. Famiglietti and M. Rodell, Water in the Balance, Science, 340, 1300 (2013). Figure appears as Figure S1 in Supplementary Online Materials, www.sciencemag.org/cgi/content/full/science.1236460/DC1 

"Any sufficiently advanced technology is indistinguishable from magic." - Arthur C. Clarke

Comments

[Account Deleted]

Agreed. GRACE just gets the ball rolling for micro scientists and ANYONE who does water management. I'm available :)

(Oh, and I'll be THERE, with free solutions too :)

[geohydro2011]

The GRACE map suggests that there are some areas of groundwater that spread across currently defined aquifers, e.g., Central Valley appears merged with part of the Great Basin--not saying GRACE is wrong, it could be that our current definition of regional aquifers is incomplete or it could be an artifact of the spatial interpolation scheme used to create the map. This is certainly exciting from a science view--can't wait to see a higher spatial resolution GRACE map. It could redefine what an aquifer is! On the other hand, if GRACE is true here, it is depressing, as regional aquifers are not managed on such a wide regional basis--certainly suggests that federal management framework/rules is/are necessary. Too, we need more ground truth, not less but I can see some politicians gutting our observation programs; bastards.