SWSIReportJuly2007 - Laserfiche WebLink

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RIO GRANDE BASIN Basinwide Conditions Assessment The SWSI value for the month was 0.5. Flow at the gaging station Rio Grande near Del Norte averaged 3327 cfs (1070/0 of normal). The Conejos River near Mogote had a mean flow of 835 cfs (660/0 of normal, due partly to direct flow storage in Platoro Reservoir). Stream flow in most areas of the upper Rio Grande Basin was near normal during June. Storage in Platoro, Rio Grande, and Santa Maria reservoirs totaled 1000/0 of normal as of the end of June. June precipitation in Alamosa was only 0.25 inches, 0.34 inches below normal. While Alamosa received significantly less precipitation than normal, precipitation in other areas of the Rio Grande basin, including the mountains, received close to a normal amount. The mean temperature at Alamosa for the month of June was 60.7 degrees, which is 1.3 degrees above normal. Outlook Both the Rio Grande and Conejos Rivers are producing much more water than was expected earlier in the year. The current forecast for the Rio Grande is an April- September total flow of 590,000 acre-feet, which is 210,000 acre-feet higher than the May 1st NRCS forecast for the same time period. Similarly, the Conejos system forecast has increased by over 43,000 acre-feet since May 1. This incredibly large change in forecast numbers has caused quite a stir in the water user community since the curtailments on both rivers have been increased substantially to account for the increased flows. By the end of June, many streams had dropped to slightly below average flows. For those drainages with storage reservoirs, releases began during the latter part of the month. Without substantial rainfall, stream flow in the upper Rio Grande basin will be significantly below normal levels after the reservoir releases are completed in July. Administrative/Manaqement Concerns Administrators have placed curtailments on indexed stream flows in order to meet water delivery requirements to the state line pursuant to the Rio Grande Compact. The current delivery targets are set at 250/0 for the Rio Grande and 160/0 for the Conejos River system. These percentages of available native flow are routed downstream past the ditches to the state line. Public Use Impacts The warm, relatively dry weather has benefited those farmers and ranchers with native grass and alfalfa crops. Most reservoirs reached peak storage levels near the end of Mayor early June and have already begun to decline as releases are made for irrigation needs. As the summer progresses, recreational opportunities may be hampered by low water levels in both reservoirs and streams in the basin. Jul-07 RIO GRANDE BASIN SNSI HISTORY 4.0 I- W S 3.0 2.0 1.0 w :3 <( > 0.0 >< w o z - -1.0 >- a:: o -2.0 -3.0 Jan-99 Jan-OO Jan-01 Jan-02 Jan-03 Jan-04 Jan-OS Jan-06 Jan-07 rvDNTH / YEAR RIO GRANDE NR DEL NORTE, FLOW BY WATER YEAR 1,200,000 Q) 1,000,000 Q) LL ill ~ 800,000 s- o Li 600,000 w > i= :5 400,000 ::J ~ ::J u 200,000 5