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, -~, IN REPLY REFER TO United States Department of the Interior BUREAU OF LAND MA"IAGEMENT Colorado State Office 2850 Youngfield Street Lakewood. Colorado 80215-7093 www.co.blm.gov CO-932 7250 DEe 1 5 2004 Mr. Dan Merriman Colorado Water Conservation Board 1313 Sherman Street, Room 721 Dcnver, Colorado 80203 Dear Mr. Merriman: The Bureau of Land Management (BLM) is writing this letter to formally communicate its instream flow recommendation for Maggie Gulch, located in Water Division 7. Location and Land Status - Maggie Gulch is tributary to the Animas River approximately five miles northeast of Silverton. The stream reach covered by the surveys conducted on BLM lands runs from the headwaters to the confluence with the Animas River. Of the 4.74 mile reach, approximately 64% is located on federal lands while the remaining 36% is privately owned. Biological Summary - Fishery surveys indicate that the creek supports a cutthroat trout fishery. The stream environment is presently in good condition and provides suitable substrate, channel stability, water quality, and food supplies for salmonids. However, the stream is very steep and high velocity, so pools and other spawning locations are limited. Accordingly, it is important to provide stream flows that maintain the limited amount of physical habitat. 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 cnvironmcnt to a reasonable degree. 2.5 cubic feet per second is recommended from May I to October 31. This recommendation was derived by averaging two R2Cross surveys. The recommendation is driven by the wetted perimeter criteria, because the stream channel has steep banks. In this type of channel, 2.5 cfs is required to provide sufficient physical habitat for the fishery during the summer months.