Aspinall Unit Seasonal Operation Goals Fill Blue Mesa

Aspinall Unit Seasonal Operation Goals • • Fill Blue Mesa Reservoir before end of runoff. Operate to the 2012 Aspinall ROD at the Whitewater Gage. Meet the NPS Black Canyon water right peak flow. Meet all state water right needs on the river downstream. Maximize hydropower production. Meet Blue Mesa Reservoir End of December ice target of 7490. 0 ft Meet flood control needs of storing water in Blue Mesa Reservoir and to avoid flooding down river in the town of Delta. • Adjust river flows for diversion needs through the Gunnison Diversion Tunnel. • Adjust flows for trout spawning needs in the fall and spring months.

Blue Mesa Reservoir, Colorado Historic April-July Unregulated Inflow Volume Ranking (1969 -2012) 1 400 000 2016 Mid March Forecasted Runoff Volume (580, 000 Acre-Feet, 86% exceedance) Wet < 10% 1 200 000 Moderately Wet 1030% Average Wet 30 -50% 800 000 Average Dry 50 -70% 600 000 Moderately Dry 70 -90% 400 000 Dry >90% 200 0 20 0 19 2 7 20 7 1 19 2 8 20 1 1 19 3 9 19 0 8 20 8 04 20 0 19 3 89 19 2 7 19 6 72 20 1 20 0 07 20 0 0 19 1 9 20 4 0 19 6 7 19 4 9 20 8 0 19 5 9 19 1 9 19 9 7 19 1 6 19 9 8 20 2 0 19 9 7 19 3 8 19 7 7 19 8 9 19 6 7 19 5 83 20 1 19 1 7 19 9 70 19 8 19 0 93 20 0 19 8 8 19 6 8 19 5 9 19 7 95 Volume (Arce-Feet) 1 000 Runoff Year

March 15 Forecast 580 KAF 4190 cfs 2006 2007 2015

Peak Flow Target at Whitewater 16000 14000 MOD WET 12000 8, 070 cfs Peak Q (cfs) 10000 AVG WET AVG DRY 8000 2006 6000 2007 4000 Apr-July Forecast Half bank Duration Peak Flow Duration (1000 AF) (days @ 8, 070 cfs) (days @ up to 14, 350 cfs) <381 0 0 381 -516 0 0 516 -709 10 0 709 -831 20 2 831 -1123 40 10 2015 MOD DRY 2000 DRY 0 200 300 400 500 600 700 800 900 1000 Forecast BM Apr-Jul Inflow (thousand af) 1100 1200 1300 1400 1500