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RIO GRANDE BASIN Basinwide Conditions Assessment The SWSI value for the month was 2.8. The Natural Resources Conservation Service reports that January 1 snowpack is 137% of normal. Flow at the gaging station Rio Grande near Del Norte averaged 224 cfs (115% of normal) during December. The Conejos River near Mogote had a mean flow of 54 cfs (103% of normal). Hydrologically speaking, 2007 was a very unusual year. Late snowstorms and unexpected monsoonal patterns bolstered the runoff from a poor snowpack. The Conejos system produced about 90% compared to long term averages and the Rio Grande about 110%. But creeks at the northern end of the San Luis Valley, such as Carnero, Saguache, and Kerber had an outstanding year. For the majority of the Division 3 streams, runoff was moderate and lengthy, without any flooding; a real benefit to area farmers and ranchers. Storage in Platoro, Rio Grande, and Santa Maria reservoirs totaled 104% of normal as of the end of December. Alamosa received 1.21 inches of precipitation during December, 0.88 inches above normal. Temperatures ranged from -33 degrees to 53 degrees in Alamosa where the average monthly temperature was only 12 degrees, about 5 degrees below normal. Several weather-related records were broken during December including over one-third of an inch of rain on December 1 and bitter temperatures late in the month. For the year, Alamosa had above average precipitation of 9.74 inches (+2.49 inches) and warmer than average temperatures. Outlook Stream flow in the basin should remain slightly above average for the next few months. Very cold temperatures in the San Luis Valley will continue as long as the snow and ice cover on the valley floor remains. Administrative/Manaqement Concerns Colorado will exceed the delivery obligation to New Mexico and Texas on the Rio Grande Compact for 2007 by about 8000 acre-feet. Approximately 710,000 acre-feet was indexed at the Rio Grande near Del Norte gaging station during 2007. Stream flow in an average year totals 630,000 acre-feet at that site. Indexed flow on the Conejos River near Mogote totaled 204,000 acre-feet compared to an average of 220,000 acre-feet. The Los Pinos and San Antonio Rivers added another 72,000 acre-feet to the index. The required delivery for Colorado on that indexed flow was approximately 304,000 acre-feet. A preliminary estimate of the amount delivered to the state line is 289,000 acre-feet. Paper credit and other standard adjustments will more than make up the difference. Closed Basin Project delivery to the Rio Grande totaled 15,000 acre-feet for 2007. All Project canal deliveries met water quality standards. Public Use Impacts Going into December, snowpack in the upper Rio Grande basin was abysmal - even prompting comparisons to 2001/2002. But three superb snowstorms since then have the basin sitting pretty at over 150% of normal; a remarkable turnaround. f- W S w ::: <{ > 0 x w o Z -.1 >- 0:: o .2 11 14O,CXXJ LL '" ~ 120,CXXJ ~ 1oo,CXXJ -' LL ~ 8O,CXXJ >= :s 60, CXXJ ::J ::;; G 4O,CXXJ Q) ~ 20, CXXJ Q) " ro ai g> 15,CXXJ o Ii) Q) m 10,CCO ::J 5 Jan-08 RJO(R.l>J\,[EBA.SN9fIS HSTCRY .3 Jm..OO Jcn-01 Jm-02 J<n-03 J<n-04 J<n-05 J<n-OO J<n-07 J<n-OO M:N1H/\S'R RIO GRANDE NR DEL NORTE FLOW BY WATER YEAR 180,CXXJ 160,CXXJ 20, CXXJ o ill NCN cec Jan Feb M3rch --8--V\ET (1987) -+-- DRY (2002) ~ AVG ""* 2m8 REPRESENTATIVE RESERVOIRS 30, CXXJ 25, CXXJ 5, CXXJ o Rio Grande Platoro Santa M3ria III Avg. 12/31 Contents III 12/31/07 Contents