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.3 ~ • UTE PASS PRESERVATION S~IETY ManitoutSprings, CO 80$29 ~ R E C E! V E D July 10, 1989 ~ JUl 1~ 1989 '~ MINED L/~-itu Mined Land Reclamation Division REOLAMATION DIVISIf~N 1313 Sherman St, Room 215 Denver, CO 80203-2273 RE: Written testimony sub~gd for Formal Public Hearing, Snyder Quarry Amendment, RD Permit No. M-77-210, AM-03 to be held July 26, 1989 Submitted herewith are my comments on the hydrology, erosion, and sedimentation in the Snyder Quarry area, and the structural integrity of the proposed silt fences and holding pond in the event of a flash flood. The east slope of the Front Range of Colorado is partic~ilarly prone to flash flooding and resulting flood damage. This has been recently documented in a lengthy newspaper article which appeared in the Colorado Springs Gazette-Telegraph, May 26, 1989. A copy of this article with pertinent passages hi-lited is in- cluded with this latter as Exhibit A. Excerpts from this; article state:"Severely sloping watersheds in E1 Paso County acs as giant funnels, quickly collecting and concentrating storm runoff into main stream channels. Steep stream gradients ensure a f:Lood velocity that packs an extra destructive punch and allows scant {:ime for warning and evacuation." The elevation of the Snyder Qu~~rry and amendment area is mostly between 7200' and 7400'.The town of Manitou Springs is mostly between 6200' and 6400' The resulting stream gradients taould be 1000' per mile for Williams Canyon drainage from the amendment area to the north edge of M~initou Springs. Blaclt Canyon, which drains the Snyder Quarry to the soui:heast, has a drop of 1000' in 1.6 miles to its' confluence with Fountain Creek. More than 30 acres of the quarry area have been stripped of soil and vegetation. In the event of a flash flood the quarry area would be one of e:ctremely high water runoff and sediment load, thereby aggravating potential flood problems. A study of the comparision of sediment loads in streams of the Colorado Springs area during 1985 to 1988 was done by Paul Vonguerard of the U.S. Geological Survey, Pueblo. The report, soon to be released, indicates that Black C«nyon Creek has the highest sediment load for the size of its' drainage basin than any other comparable stream. The 30 acres of stripF~ed,unstabili- zed ground of the Snyder Quarry and the haul road down Etlack Canyon are probable contributing factors to the high sedimentation rate. Higher reclamation standards, and reclamation contemporaneous with quarrying would help mitigate the high erosion rate and decrease the potential damage caused by flooding. A Q100 storm event "occurred in this area on May 12, 1941. Included with this letter is a copy of the Gazette-Telegraph article that graphically describes the flood damage. This is Exhibit B.