This assessment was conducted from the base of Ruedi dam, at an elevation of 7485’ down to the confluence with the Roaring Fork River where the elevation is 6580’. From the dam to the confluence, the landscape alternates frequently between narrow canyons to wide valleys. Rural development, interspersed with some State and USFS lands, characterizes current land use throughout the valley below the dam. However, home development is rapidly escalating and the Frying Pan Road is now heavily traveled by commuters, recreationists and construction workers, so much so that the road has become a considerable hazard to wildlife. Human-induced impacts to the stream correspond to the landscape. Typically in the narrow canyons the road channelizes the stream, destabilizes uplands and the stream bank, and is an ongoing source of excess sedimentation. In the wider valleys, the road dissects the floodplain isolating portions of the riparian zone from the stream and straightening the stream. Home/ranch development has contributed to channelization by removing riparian vegetation, and building in the floodplain. In the Town of Basalt, the dramatic increase in the amount of impermeable surface alters precipitation infiltration resulting in greater flooding flows and lower base flows. Additionally, water quality is degraded by runoff that is heated by contact with asphalt and laden with road-based pollutants.

Overbanking occurs infrequently and then only to a minimal extent due to dam-controlled hydrology. Controlled flows have allowed extensive home development in the flood plain. That development now prevents dam releases that mimic a natural flooding flow. Throughout the lower Frying Pan, impacts to the stream from the combination of unnaturally controlled flows and channelization include: width/depth ratios that are inappropriately high; excess sedimentation and embeddedness; excessively high abundance of periphyton; and lack of cutbank-pointbar development.