Hydrologic Conditions: Colorado River Basin, September 2015

Current Conditions

Lake Mead: Lake Mead’s current elevation is now 3.04 feet below the elevation of Lake Mead in September 2014 and 88.12 feet below the historical September elevation of Lake Mead.

Lake Powell: Lake Powell’s current elevation is now 1.56 feet ABOVE the elevation of Lake Powell in September 2014 but is still 31.47 feet below the historical September elevation of Lake Powell.

24-Month Study

Lake Mead: The September 2015 24-Month Study projects that Lake Mead’s January 2016 elevation will be 1,083.16 feet, or 8.16 feet above the trigger elevation for a declaration of a shortage condition for 2016.  Nevertheless, the trend continues toward increased shortage risk accelerated in the Lower Colorado River Basin, perhaps as early as 2017.

Actual Lake Mead elevations in 2013 and 2014 are generally running below forecasted levels in January 2013 and January 2014.  The 24-month study for September 2014 projected even lower Lake Mead elevations than earlier forecasts.  With a recent rebound in inflows, the forecasts prepared this summer are above the August 2014 forecast.

Lake Mead elevation is forecasted to fall below the trigger for shortages in late spring 2016 but rebound towards the trigger for January 2017.  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: The September 2015 24-Month Study projects a continued upward trend in Lake Powell elevations.  Actual Lake Powell elevations in 2013 were generally running below forecasted levels in January 2013.  January 2014 forecasts were significantly lower than January 2013 forecasts.  August 2014 forecasts of Lake Powell Elevation increased significantly in the latter part of the forecast period.   The August and September 2015 forecasts are slightly above the August 2014 forecast.  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 Historical Average

Lake Mead: Monthly elevations in 2015 are lower than in 2014 and even further below historical monthly average elevations.

 

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