Table 2 Groundwater change rates and total groundwater volume changes in the three sub-basins in the study region
From: Groundwater depletion in California’s Central Valley accelerates during megadrought
Sacramento (72,015 km3) | San Joaquin (40,986 km3) | Tulare (42,512 km3) | |||||||
|---|---|---|---|---|---|---|---|---|---|
Change rate (mm/yr) | Change rate (km3/yr) | Volume change (km3) | Change rate (mm/yr) | Change rate (km3/yr) | Volume change (km3) | Change rate (mm/yr) | Change rate (km3/yr) | Volume change (km3) | |
Oct. 2003–Jul. 2006 (1st recharge, Fig. 6a–c) | +39.0 ± 20.0 | +2.81 ± 1.44 | +8.0 ± 2.4 | −6.4 ± 29.6 | −0.26 ± 1.21 | −0.7 ± 2.0 | +27.5 ± 15.8 | +1.17 ± 0.67 | +3.3 ± 1.1 |
Aug. 2006–Feb. 2011 (1st drought, Fig. 6a–c) | −43.7 ± 8.7 | −3.15 ± 0.63 | −14.4 ± 1.3 | −44.7 ± 12.9 | −1.83 ± 0.53 | −8.4 ± 1.1 | −40.1 ± 6.3 | −1.70 ± 0.27 | −7.8 ± 0.6 |
Mar. 2011–Jul. 2011 (2nd recharge, Fig. 6a–c) | +570.6 ± 117.2 | +41.09 ± 8.44 | +17.1 ± 5.4 | +627.4 ± 135.1 | +25.71 ± 5.54 | +10.7 ± 3.6 | +439.2 ± 68.7 | +18.67 ± 2.92 | +7.8 ± 1.9 |
Aug. 2011–Mar. 2017 (2nd drought, Fig. 6a–c) | −34.0 ± 8.0 | −2.45 ± 0.58 | −13.9 ± 1.4 | −40.4 ± 9.9 | −1.66 ± 0.41 | −9.4 ± 1.0 | −62.9 ± 4.4 | −2.67 ± 0.19 | −15.1 ± 0.4 |
Oct. 2018–Aug. 2019 (3rd recharge, Fig. 6a–c) | +309.0 ± 123.6 | +22.25 ± 8.90 | +20.4 ± 8.5 | +225.0 ± 123.7 | +9.22 ± 5.07 | +8.5 ± 4.9 | +125.3 ± 64.3 | +5.33 ± 2.73 | +4.9 ± 2.6 |
Sep. 2019–Dec. 2021 (Present drought, Fig. 6a–c) | −76.1 ± 28.1 | −5.48 ± 2.02 | −12.8 ± 3.1 | −38.1 ± 25.2 | −1.56 ± 1.03 | −3.6 ± 1.6 | −60.1 ± 14.0 | −2.55 ± 0.60 | −6.0 ± 0.9 |
Sep. 2003–Aug. 2017 (Lifetime of GRACE) | −16.9 ± 2.6 | −1.22 ± 0.18 | −17.1 ± 0.7 | −17.7 ± 3.2 | −0.73 ± 0.13 | −10.2 ± 0.5 | −25.9 ± 2.3 | −1.10 ± 0.10 | −15.4 ± 0.4 |
Sep. 2003–Dec. 2021 (Megadrought, Fig. 6a–c) | −12.9 ± 1.8 | −0.93 ± 0.13 | −17.0 ± 0.5 | −16.2 ± 1.9 | −0.67 ± 0.08 | -12.2 ± 0.3 | −20.6 ± 1.5 | -0.88 ± 0.06 | −16.1 ± 0.3 |
