Basins

Below normal

Colorado (Lower) basin

Reservoir storage across Arizona / California / Nevada

Data through Aug 25, 2026 · source last checked Aug 27, 2026 · page revised Aug 27, 2026

Cite
acre-feet
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About this data
Source
US Bureau of Reclamation RISE; California reservoirs via CA DWR CDEC
Series
Reservoir storage summed across the basin
Geography
Colorado (Lower) basin
Unit
acre-feet
Calculation
Daily reading
Last observation
Aug 25, 2026
Update frequency
Daily

Now 9.21M af, 16% below the 5-yr median.

Lower Colorado basin storage stands at 9.21M af, down 10.8% year-over-year and 16% below the 5-year median. Storage fell 0.4% on the week and 1.8% on the month.

The numbers
PeriodCurrentPriorChange
Week over week9.21M af9.24M af-0.4%
Month over month9.21M af9.37M af-1.8%
Year over year9.21M af10.32M af-10.8%
vs 5-yr median9.21M af10.90M af-15.5%

Previous weeks

Week of Aug 19, 2026

Colorado (Lower) basin storage stands at 9.23M af, down 10.3% year over year. The basin sits 15% below the 5-year median and shed 1.9% over the past month.

An earlier week

Lower Colorado basin storage stands at 9.25M af, down 10% year over year. The aggregate is 15% below the 5-year median.

Week of Aug 13, 2026

Lower Colorado basin storage at 9.28M af, down 9.7% from last year and 14% below the 5-year median. Storage has declined 2.3% this month.