FLOOD10420 - Laserfiche WebLink

Home Browse Search

- 11 II 11 11 il il il ;1 :1 :1 :1 :1 :1 ]1 II II 11 II II Lower Big Dry Creek Hydrologic Study For the most part, key findings from these reports relevant to this study were condensed and summarized in the Big Dry Creek Watershed Management Plan (WWE 2002), which was developed to provide a comprehensive framework for the activities of the BDCW A. The Plan condensed the findings of over five years of work by the BDCW A and was developed in conformity with the U.S. Environmental Protection Agency's (EPA's) Watershed Restoration Action Strategy (WRAS) guidelines. The Plan covers a broad range of topics including targeting (characterizing) current watershed conditions, identifying measures to protect and restore the watershed, and identifying the methods used to evaluate the watershed and activities of the BDCW A. Five out of the ten conclusions in the Plan addressed hydrologic concerns as key priorities for the wllltershed, including hydrologic effects of erosion, sedimentation and streambank stability in the lower portion of the watershed. Several key excerpts from the Watershed Plan are repeated below because they provide good background information for this project. A key excerpt from the Big Dry Creek Stream Survey (WWE 2000), which covered the entire length of Big Dry Creek at a "macro" level, follows as quoted in the Big Dry Creek Watershed Management Plan: During 1998-1999, non-point sources of pollution, particularly erosion and sedimentation, were identified as an area in need of more study with regard to developing an overall understanding of water quality conditions in Big Dry Creek. In response to this need, an engineering stream survey of Big Dry Creek, including both field and office research, was conducted by Wright Water Engineers (WWE) under a 319 grant to identify key areas subject to erosion and sedimentation and other non- point sources of pollution. Aerial photography, videography and interviews with watershed residents and city staff were used to focus on portions of Big Dry Creek that were believed to be of highest priority with regard to erosion and sedimentation. Based on field surveys and evaluation of available data, some of the key conclusions regarding the geomorphology of Big Dry Creek in the WWE (2000) report included: . As a whole, the main stem of Big Dry Creek is not experiencing excessive sedimentation and erosion; however, there are localized areas in both the urban and agricultural areas where erosion is occurring and where improvements can be made. . Big Dry Creek is now a perennial stream that is subject to erosion of outside bends of the channel. The creek has some extreme bends with several oxbow type 971-179.092 June 2005 Wright Water Engineers, Inc. Page 21