From email from Reclamation (Dan Crabtree):
The Colorado Basin River Forecast Center (CBRFC) has issued the final May 1st forecast. In the two week period between April 18th and May 2nd the CBRFC forecasts that the runoff into Blue Mesa Reservoir has increased by 145,000 ac-ft to 945,000 ac-ft. This changes the Black Canyon water right one day peak target to 6,800 cfs. Although additionally challenging, Reclamation still plans to operate the Aspinall Unit in a manner which will allow this peak target to be met. Our tentative plans are to implement this peak operation toward the latter part of May or first part of June, depending on the hydrologic behavior of other tributaries. This peak operation will require a spill at Crystal Reservoir of around 3,000 cfs. Normally Reclamation attempts to manage the peak in the mid to late May timeframe, however in some years weather and runoff conditions may dictate the peak occur at a later time.
Also, additional space is required in the Aspinall Unit to accommodate this year’s projected runoff. Consequently, releases from Crystal Reservoir will increase by 100 cfs per day until May 16th when flows in the Black Canyon and Gunnison Gorge will reach about 2,500 cfs. At that time, the mid-May forecast will be evaluated and further increases are likely for the remainder of that week. Further updates will be provided as the time of peak operation approaches.
More Aspinall Unit coverage here.