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RIO GRANDE BASIN Basinwide Conditions Assessment The SWSI value for the month was +3.1. The Natural Resources Conservation Service reports that April 1 snowpack is 140% of normal. Flow at the gaging station Rio Grande near Del Norte averaged 303 cfs (113% of normal). The Conejos River near Mogote had a mean flow of 110 cfs (140% of normal). Flow to the state line was 144% of normal. Storage in Platoro, Rio Grande, and Santa Maria reservoirs totaled 110% of normal as of the end of March. Weather conditions in the San Luis Valley and surrounding mountains were much drier than normal during March. Alamosa received only 0.13 inches of precipitation during the month, 0.33 inches below normal. The mountains received only one-third of the normal amount. Outlook Recent NRCS stream flow forecasts are calling for a range of about 120% of normal (Sangre de Cristo Range from Culebra Creek northward to Ute Creek near Fort Garland) to 189% (Rio San Antonio drainage) of average runoff this year. Expected runoff at the Rio Grande near Del Norte gaging station is 140 percent of normal and 150 percent of average for the Conejos near Mogote. These estimated runoffs are approximately 10 to 30% lower than the March 1 forecasts. This reflects the below normal snowfall in the mountains surrounding the San Luis Valley during the past 30 days. Based on the 90-day climate forecast (warm and dry) and snowpack summaries available from the Natural Resources Conservation Service, the maximum snow water equivalent accumulation has already been reached during 2008. This usually occurs on April 1 O. But the peak this year was probably reached on March 20. Administrative/Manaqement Concerns Local officials are now less fearful of damaging floods during the 2008 runoff season. Depending on the severity of the melt-out, runoff levels might be just slightly above normal. The 2008 annual meeting of the Costilla Creek Compact Commission will be held at the Clarion Inn of the Rio Grande in Alamosa on May 8, 2008 at 10 a.m. The public is invited to attend. Public Use Impacts Despite the dry March, winter sports enthusiasts reliant on snowcover still enjoyed the deep snowpack. Finally, enough sun and warmth freed the lower elevations from ice and snow cover and temperatures rose to a moderate level. It is anticipated that the irrigation season will begin around April 11. f- W S w ::: <t > 0 x w o Z -.1 >- 0:: o .2 160,000 1l14O,000 LL dJ ~ 120,000 ~ 100,000 -' LL ~ 80,000 >= :s 60,000 ::J ::;; ::J 40,000 U ~ 25,000 Q, " ro 20,000 Q) Ol ro o ii5 15,000 Q) :0 ro <f> ::J 10,000 5 Apr-08 RJO(R.l>J\,[EBA.SN9fIS HSTCRY .3 Jm..OO Jcn-01 Jm-02 Jcn-03 Jen-04 Jcn-05 Jen-OO Jcn-07 Jm-OO M:N1H/\S'R RIO GRANDE NR DElL NORTE FLOW BY WATER YEAR 180,000 20,000 o Cct Nov Dee Jan Feb M3rch --8-V\ET (1987) -+- DRY (2002) ~AVG "*- 2OJ8 REPRESENTATIVE RESERVOIRS 35,000 30,000 5,000 o Rio Grande Platoro Santa Maria IIIIAvg. 3/31 Contents 113/31/08 Contents