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STATE OF COLORADO <br />RicharA D. Lamm, Gorcrnor <br />DEPARTMENT OF NAi URAL RESOURCES <br />OF WILDLIFE <br />'Jack R. Gneb, Director <br />6060 Broadway <br />Denver, Colorado 80216 (825-1142) <br />1983 <br />Mr, Scott Sones <br />Environmental Coordinator <br />Snowmass Coal Company <br />PO Box 980 <br />Carbondale Colorado <br />RECEIVED <br />JUN °!~ 19y j <br />w'~WtMK COAL CO, <br />81623 <br />~o~ARrtoo <br />~~'~~ ~Ov <br />'Y OF'~ <br />Scott, <br />I have reviewed some additional literature concerning fish passage .and structures <br />which may impede fish passage, Some of the information applies to the Thompson <br />~' Creek weirs so 1 thought I would pass the highlights along to you in this letter for <br />Snowmass Coal Company's consideration, The information is from The McGonau~hY <br />Rainbow... Life History and a Management Plan for the North Plakte River Valley <br />by Rodney C, Van Velson (A Contribution of the Federal Aid in Sport Fish Restoration <br />"A pool of quiet yvater <br />pool provides a resting <br />take-off pool below any <br />the barrier is high, " <br />should be located immediately below any instream obstacle. This <br />area and a 'good start' for the fish to bypass the obstacle. A <br />obstacle across the stream should be 1'-i to 2 times deeper than <br />"Any structure which creates a vertical drop over one foot should be avoided if possible." <br />(If not possible several guidelines should be followed 1, "All verticle drops over one foot <br />should be investigated to make sure the water velocities and the water depth both in the <br />pools below and over the structure are within the recommended guidelines, " <br />"A minimum water depth of eight inches is necessary to insure unimpeded rainbow <br />trout migrations, " Notches in the weirs should be designed to maintain the eight inches. <br />"Maximum water velocities caused by any stream alteration should not exceed four <br />feet per second, " I note in your letter of May 20, 1983, that the maximum velocities <br />will be 2, 2 feet per second, <br />"Construction activity should be limited to May through September, No construction <br />should take place from October through April whe1T rainbow trout migrations are <br />under way, Every effort should be made during construction to keep debris and siltation <br />at a minimum level, If a cement apron is necessary in an area immediately below ... <br />it should be placed below the stream grade. " <br />UEPARTMENT OF NATURAL RESOURCES, Harris Sherman, Executive Direuor WILDLIFE COMMISSION, Michael Higbee, Chairman <br />Wilbur Redden, Yke Chairman • Snm Caudill, Secretary • lean K Tool, Member • Vernon C. Williams, Member <br />. ~ ..~ ..-_~.. nnnald Fernandez. Member • Richard Divel bins, Member <br />