Fawn Ridge

In the summer of 2015, McAdams conducted a stream condition assessment and provided a feasibility report for the Town of Knightdale to restore an impaired stream. The impaired stream was highly eroded with a four-foot localized headcut that had progressed upstream through engineered fill and exposed a saprolite subgrade layer where the channel incision was most significant. Stream erosion had caused trees located on the stream banks to fall and was threatening the back porch of a local residence. The stream assessment / feasibility report was completed to analyze the current impaired condition of the stream, provide recommendations for stabilizing and/or restoring the stream and develop a strategy to mitigate future property damage. Three recommendations were presented within the feasibility report. Ultimately, the option chosen by the Town involved relocating the stream back into the public drainage easement and designing a new adequately sized channel with appropriate stabilization. The project area was surveyed and final designs were completed for the project. The channel cross-sectional dimension and longitudinal profile were developed utilizing Rosgen-based natural channel design principles. The stream alignment was determined by the existing drainage easement. The restoration design resulted in a riffle-pool channel profile, reinforced by in-stream structures such as brush toe and rock / wood cluster riffles, raised to re-establish floodplain connectivity and stop further channel incision. The new channel, floodplain and any disturbed areas within the project area were proposed to be vegetated with transplants, bare-root seedlings and live stakes and seeded with temporary and permanent ground cover. Erosion control matting, temporary / permanent seeding and live stakes were proposed on the channel banks immediately following completion of each channel segment, providing stabilization for the new stream banks.