Stream: San Miguel River Executive Summary

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Staff Analysis and Recommendation Summary The information contained in this report and the associated instream flow file folder forms the basis for staff's instream flow recommendation to be considered by the Board. It is staff's opinion that the information contained in this report is sufficient to support the findings required in Rule 5.40. Colorado's Instream Flow Program was created in 1973 when the Colorado State Legislature recognized "the need to correlate the activities of mankind with some reasonable preservation of the natural environment" (see 37 -92 -102 (3) C.R.S.). The statute vests the CWCB with the exclusive authority to appropriate and acquire instream flow and natural lake level water rights. In order to encourage other entities to participate in Colorado's Instream Flow Program, the statute directs the CWCB to request instream flow recommendations from other state and federal agencies. The Bureau of Land Management (BLM) and Colorado Division of Wildlife (CDOW) recommended this segment of the San Miguel River to the CWCB for inclusion into the Instream Flow Program. The San Miguel River is being considered for inclusion into the Instream Flow Program because it has a natural environment that can be preserved to a reasonable degree with an instream flow water right. The San Miguel River is approximately 70 miles long. It begins on the north side of Wasatch Mountain at an elevation of 9,100 feet and terminates at the confluence with the Dolores River at an elevation of 4,900 feet. Of the 17.24 mile segment addressed by this report, approximately 28% of the segment is located on federal lands. This segment of the San Miguel River is located within Montrose County and generally flows in a northwesterly direction. The San Miguel River has a total drainage area of approximately 1,500 square miles. The San Miguel Basin is the largest tributary to the Dolores River and is part of the Upper Colorado System. The one million acre San Miguel Basin is about 60 % semi -arid rangeland and agricultural land, both comprising the lower elevations. The remaining 40% of the basin is in higher elevation, forested subalpine and alpine zones in the San Juan Mountains. Most of the flow in the San Miguel River (240,000 acre -feet per year) is derived from snowmelt at higher elevations. Because of its relatively low human population density and lack of large water storage impoundments, the San Miguel Basin is considered to be one of the few ecologically and hydrologically intact river basins in Colorado. The subject of this report is a segment of the San Miguel River beginning at the confluence with Calamity Draw and extending downstream to the confluence with the Dolores River. The proposed segment is located approximately 3 miles west of the Town of Nucla. The staff has received one joint recommendation for this segment, from the BLM & CDOW. The recommendation for this segment is discussed below. Instream Flow Recommendation The BLM & CDOW are recommending 325 cfs (April 15 — June 14), 170 cfs (June 15 — July 31), 115 cfs (August 1— August 31), 80 cfs (September 1 — February 29) and 115 cfs (March 1 — April 14) based on their data collection efforts and staff's water availability analyses. -2-