Hydrologic implications of GRACE satellite data in the Colorado River Basin

Abstract

Use of GRACE (Gravity Recovery and Climate Experiment) satellites for assessing global water resources is rapidly expanding. Here we advance application of GRACE satellites by reconstructing longterm total water storage (TWS) changes from ground-based monitoring and modeling data. We applied the approach to the Colorado River Basin which has experienced multiyear intense droughts at decadal intervals. Estimated TWS declined by 94 km 3 during 1986-1990 and by 102 km 3 during 1998-2004, similar to the TWS depletion recorded by GRACE (47 km 3 ) during 2010-2013. Our analysis indicates that TWS depletion is dominated by reductions in surface reservoir and soil moisture storage in the upper Colorado basin with additional reductions in groundwater storage in the lower basin. Groundwater storage changes are controlled mostly by natural responses to wet and dry cycles and irrigation pumping outside of Colorado River delivery zones based on ground-based water level and gravity data. Water storage changes are controlled primarily by variable water inputs in response to wet and dry cycles rather than increasing water use. Surface reservoir storage buffers supply variability with current reservoir storage representing 2.5 years of available water use. This study can be used as a template showing how to extend short-term GRACE TWS records and using all available data on storage components of TWS to interpret GRACE data, especially within the context of droughts.

Recent changes in terrestrial water storage in the Upper Nile Basin: an evaluation of commonly used gridded GRACE products

“…Another source of uncertainty that contributes toward TWS anomalies in GRACE analysis is the choice of simulated SMS from various global-scale LSMs (e.g. Shamsudduha et al, 2012;Scanlon et al, 2015). For example, the mean annual (2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012) amplitudes in simulated SMS in GLDAS LSMs (CLM, NOAH, VIC) vary substantially in the LVB (3.5, 10.2, and 10.5 cm) and LKB (3.7, 10.6, and 7.7 cm) respectively.…”

“…Further, analyses of GRACE-derived GWS often assume SWS is limited (Kim et al, 2009), yet studies in the humid tropics and engineered systems challenge this assumption, showing that it can overestimate GWS (Shamsudduha et al, 2012;Longuevergne et al, 2013). Robust estimates of GWS from GRACE gravity signals have, to date, been developed in locations where SWS is well constrained by in situ observations and groundwater is used intensively for irrigation so that GWS comprises a significant (> 10 %) proportion of TWS (Leblanc et al, 2009;Shamsudduha et al, 2012;Scanlon et al, 2015). In sub-Saharan Africa, intensive groundwater withdrawals are restricted to a limited number of locations (e.g.…”

Groundwater Development Stress: Global‐Scale Indices Compared to Regional Modeling

“…The GDS depl index reflects net storage changes as the integrated result of pumping, climate, and altered groundwater recharge due to irrigation and land-use changes. Several studies illustrate the challenges of separating soil moisture storage from GRACE estimates of total water storage in calculating groundwater storage changes (Long et al 2013;Breña-Naranjo et al 2014;Scanlon et al 2015). The shorter period (post 2002) for which GRACE data are available, however, makes it more difficult to distinguish climate vs. pumping effects (Alley and Konikow 2015;Döll et al 2015).…”

“…Scanlon et al (2015) illustrate the utility of multiple types of data in distinguishing between human and climatic effects on groundwater storage in the Colorado River Basin. Scanlon et al (2015) illustrate the utility of multiple types of data in distinguishing between human and climatic effects on groundwater storage in the Colorado River Basin.…”

Large-Scale Total Water Storage and Water Flux Changes over the Arid and Semiarid Parts of the Middle East from GRACE and Reanalysis Products

“…By combining various remote sensing data and LSM outputs in a hydrological model, Mulder et al (2015) indicate that the GRACE TWS depletion within northern Iraq during 2007-2009 is mainly explained by a lake mass exploitation. In fact, hydrological processes such as surface and groundwater (lateral) flow might significantly change TWS patterns as has been discussed, e.g., in Scanlon et al (2015). This impact is expected to be strong within the Tigris-Euphrates river basin and to a less extent within Iran's river basins, e.g., Urmia and Persian basins, see, e.g., Hosseini and Ashraf (2015) for more details, and Fig.…”