June Drought Update from CWCB

Arkansas Basin June 11, 2011 – June Drought Update

Information Provided by CWCB-Colorado Water Conservation Board

Basinwide Conditions Assessment

The SWSI value for the month was -1.4. Flow at the gaging station Arkansas River near Portland was 701 cfs, as compared to the long-term average of 1,175 cfs. Storage in Turquoise, Twin Lakes, Pueblo, and John Martin reservoirs totaled 83% of normal as of the end of May. 

Outlook

Unlike May of 2010 when the Arkansas River flows appeared to experience a near peak flow by the end of May (Arkansas River at Portland peaked at just below 4,000 cfs in late May 2010), runoff in 2011 has been lethargic and river calls have stayed very senior. A significant snowpack in the upper basin, and the prospect of potentially large transmountain imports from the Fryingpan-Arkansas Project, cause farmers to have hope of a good year, but current stream flow conditions are alarming to those who are making planting decisions. Irrigation well pumping has been occurring at the highest levels in over a decade for the period March through May.

The river call at the beginning of the month was Fort Lyon Canal’s #1 water right (4/15/1884) with the Lamar Canal’s #2 water right (11/4/1886) below John Martin Reservoir being the call for most of May. The river call became slightly more junior towards the latter part of May with the Catlin Canal (12/3/1884) above John Martin Reservoir and the Amity Canal (2/21/1887) below John Martin Reservoir being the calling rights the last few days of the month.

Administrative/Management Concerns

Supplies have been short and river calls very senior on the southern tributaries (Purgatoire River, Cucharas River, Huerfano River and St. Charles River) as well as on Fountain Creek. Calls on these tributaries are significantly senior to Arkansas River mainstem calls (1866 to 1870).

Reservoir stored water in John Martin Reservoir for irrigation use has been largely exhausted except for a few ditches.  Kansas has not yet called for the release of approximately

10,500 acre-feet of supply they hold in John Martin Reservoir for irrigation and have not called for release of the well augmentation water held in the Offset Account in John Martin Reservoir (approximately 8,500 acre-feet). Release of this pool of nearly 20,000 acre-feet will significantly shrink the John Martin Reservoir pool which contained nearly 36,000 acre-feet at the end of May.