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,. ,; U.& Del'l'\IIlloIENTOFTlE INTEAlOR ElUAEAUOFLIINDo.IANAGEMfNT IN REPLY REFER TO: United States Department of the Interior BUREAU OF LAND MANAGEMENT Colorado State Office 2850 Youngfield Strcct Lakewood, Colorado 80215-7093 CO.932 7250 www.co.blm.gov DEe 15 2004 Mr. Dan Merriman Colorado Water Conservation Board 1313 Sherman Street, Room 721 Denver, Colorado 80203 Dear Mr. Merriman: The Bureau of Land Managemen1 (BLM) is wri1ing 1his leUer 10 fonnally communicate its in stream flow recommendation for Cottonwood Creek, located in Water Division 4. Location and Land Status - Cottonwood Creek is tributary to the San Miguel River approximately nine miles northeas1 ofNaturita. The stream reach covered by the surveys conducted on BLM lands runs from the confluence with Little Cottonwood Creek to the confluence with the San Miguel River. Of the 3.25- mile reach, approximately 59% is located on federal lands while the remaining 41 % is privately owned. Biological Summary - Fishery surveys indicate that the stream environment is presently in stable condition, and supports a self-sustaining speckled dace fishery. In addition, the creek also provides habitat for migratory trout from the San Miguel River during spring runoff'. Channel slabilily, bank stability, and substrate is suitable for the fish population. This slream experiences very low flows during the late summer and fall, which severely limits available habitat and food supplies and confines the speckled dace population to pools. Accordingly, it is important to provide stream flows during snowmelt runoff. This protects the limi1ed time period when habitat and food is readily available and assures the continued existence of the fishery. R2Cross Analysis - BLM's data analysis, coordinated with the Division of Wildlife, indicates that the following flows are needed to protect the fishery and natural environment to a reasonable degree. 3.00 cubic feet per second is recommended for the snowmelt runoff period from April 1 to June 15. This recommendation is driven by the average depth criteria. Maintaining the average dep1h criteria is important for speckled dace spawning and for providing additional physical habitat for trou1 that move up in10 1he creek from 1he San Miguel River during snowmelt runoff. Pro1ecting snowmelt runoff flows is also important for recharging the alluvial aquifer, which discharges water to the slream and maintains flow levels during later summer. BLM is not making an instream flow recommendation for the remainder of the year. Naturally low flows, combined wi1h upstream irrigation diversion, results in extremely low flows during the remainder of the year. Speckled dace are able to survive in pools with this very low flow, but the