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Appendix B Newsletter INewspaper Articles TELLURIDE, COLORADO Newslener NO.1 The Watershed Connection, Fall 2001 Volume 13 A Publication of the San Miguel Watershed Coalition Flash Flood Hits Upper River On August 8th a flash flood in the upper San Miguel Canyon between Deep Creek and Leopard Creek was estimated by Grand Junction National Weather Service to have dropped over four inches of rain in forty minutes, more than any historically recorded event. Mud and debris piled up on Highway 145 stranded motorists for hours. A storm of this magnitude, and the required cleanup can alter the river ecosystem and affect local citizens for years to come. Our typical summer weather pattern consists of beautiful warm days, and afternoon thunderstorms. Occasionally thunderheads build up over the desert, collide with the high peaks of the San Miguel Range west of Telluride, and cause torrential downpours. Rainfall rates can exceed two inches per hour, or even up to three times that rate. The river was flowing at about 250 cubic feet per second (cfs) prior to the storm and peaked well over 2000 cfs shortly thereafter, the highest recorded flow for the year, effecting the entire river system for seventy miles downstream. Upper San Miguel side canyons are typically very steep and narrow, fed by both local rains and rainfall on expansive mesas 500 feet above. During rain events, large amounts of water and mud mixed with debris, rocks, boulders and trees cascade down the gullies. The debris flows affect the river ecosystem and local geology by depositing massive amounts of fine red silt in the river bed, sometimes altering its course. Flash flood flows can change the aquatic biology, fishery and indigenous wildlife in the riparian zone. Changes to the river channel may effect recreational uses including fishing, rafting and kayaking. Newly transported boulders and modified gravel bars change flow patterns, altering fish habitat and changing rapids. CDOW biologist Sherman Hebein claims silt flows can directly effect existing and future trout populations. Aquatic insects, their primary food source, can be smothered under stream bottom silt, damaging natural food chain processes. Young fingerling fish can be killed, and adult fish impaired by silt in their gills, abrasion against rocks or even burial in sediment. However, fish often handle silt better than expected. Observations of "good-sized" trout in Leopard Creek the day after the 1999 flash flood event, when the San Miguel reached 2500 cfs, support this. Local fishing guides concur that fish in the impacted area this year were effected, but that fishing upstream improved shortly after the flood. The effects of debris flows in the canyon could continue for years. Another impact to river corridor health is the cleanup by CDOT of the massive amount of debris deposited on the highway. Every drainage and culvert was cleared, and material transported to other locations. Some material was pushed over the edge toward the river disturbing natural vegetation. Other material was stockpiled, creating new level pullouts. The cleanup effort may cause increased siltation of the river in the future. Effects of enlarged and additional vehicular parking areas are unknown. Additional impacts resulted from fiber optic cable installation directly after debris flows. The River road has been closed to vehicles for five years, and riparian vegetation was recovering remarkably. It will take quite a while for the vegetation to recover. Th health of the San Miguel River system will continue to be effected by man made and natural events. We continue to learn how they affect our complex, unique and incredibly beautiful watershed. All watershed citizens must work together to address the impacts and cleanup of maj or flash flood event. By Ascenzo DiGiacomo, SMWC T: \Projects\6844888 _ CWCS _Flood _ Doc_ Rpts\Su b _ 00\6.0 _Proj_ Deliv\Report\Append ix S.doc T: \Projects\6844888 _ CWCS _Flood _ Doc_ Rpts\Su b _ 00\6.0 _Proj_ Deliv\Report\Append ix S.doc