Hydrologic Conditions: Colorado River Basin, December 2015

Current Conditions

Mead current (12-2015)_FINAL

Lake Mead:Lake Mead’s current elevation is now 7.49 feet below the elevation of Lake Mead in December 2014 and 83.97 feet below the historical November elevation of Lake Mead.

Powell current (12-2015)_FINAL
Lake Powell: 
Lake Powell’s current elevation is now 4.78 feet ABOVE the elevation of Lake Powell in December 2014 but is still 30.31 feet below the historical December elevation of Lake Powell.

 

24-Month Study

Mead 24-Month (12-2015)_FINALLake Mead:
The December 2015 24-Month Study projects that Lake Mead’s January 2016 elevation will be 1,084.86 feet, or 9.86 feet above the trigger elevation for a declaration of a shortage condition for 2016. Nevertheless, the trend continues toward increased shortage risk in the Lower Colorado River Basin, perhaps as early as 2017.

Actual Lake Mead elevations in 2013 through early 2014 followed projections from the January 2013 study, when actual elevations plummeted generally following the projections from the August 2013 study. The August 2014 study projected a slight increase in Lake Mead elevations which was slightly below actual elevations. With a recent rebound in inflows, the forecasts prepared this summer are above the August 2014 forecast.

The August 2015 study forecasts that Lake Mead elevations will fall below the trigger for shortages in late spring 2016 but rebound towards the trigger for January 2017. The December 2015 projections are slightly below the August 2015 projections. Right now, the prospect for a shortage declaration in 2017 for the Colorado River Basin sits on a “knife edge.”

The continuing trend of progressively lower “highs” in successive winter elevations and lower “lows” in successive summer elevations belies a continuing downward trend in Lake Mead elevations. 2017 is looking like the first time shortages may be triggered in the Lower Basin.

Lake Powell:Powell 24-Month (12-2015)_FINAL
The December 2015 24-Month Study reverses a projected upward trend in Lake Powell elevations. The December 2015 projections reach the same levels as the August 2014 projections.  Actual Lake Powell elevations in 2013 were generally running below forecasted levels in January 2013, but above the levels projected in the August 2013 study. Actual elevations have generally tracked the projections in the August 2014 study. The August 2015 study projected elevations above the August 2014 study.

The trend of progressively higher “highs” in successive June elevations and higher “lows” in successive March elevations continues. When will Powell elevations reach their peak?

Monthly Elevations

 

Mead monthly history (12-2015)_FINAL
Lake Mead: Monthly elevations in 2015 remain lower than in 2014 and almost 90 feet below historical monthly average elevations.

Powell monthly history (12-2015)_FINAL

Lake Powell: Monthly elevations in 2015 are higher than in 2014 but remain about 30 feet below historical monthly average elevations.