49 Wrangler Road 36-inch Corrugated Metal Pipe Repair Project

Watershed Protection (WP) is proposing to repair a 36-inch Corrugated Metal Pipe (CMP) to correct facility and erosion damage within its 15-foot-wide right of way easement on private property. A sinkhole and erosion damage observed following the 2023/2024 storm season resulted from corrosion leading to structural failure of the CMP, which carries residential street runoff from Wrangler Road to Bus Canyon Drain in Challenger Park in Simi Valley. Approximately 145-feet of the 36-inch CMP from the existing manhole cover in the central area of the property to the downstream concrete collar located 20-feet upstream of the headwall will be repaired by filling damaged sections with a cement sand slurry mixture and then lining it with a cured-in-place pipe (CIPP). The eroded areas would be cleared of all debris and oversized rocks (greater and 3-inch diameter), backfilled with 70-cubic yards of imported earthen fill material from Runkle Stockpile, and recompacted to 90% relative density. The 21-feet of CMP from the concrete collar to the headwall will be removed and replaced with 36-inch Class I Reinforced Concrete Pipe (RCP). The existing concrete headwall will be removed and replaced with grouted 1-ton rock riprap around the 36-inch Class I RCP. This new trapezoidal headwall will be 6-feet high from its footing apparent at ground surface, 25-feet in length at its top elevation, and approximately 4-feet wide, which is a minor increase of about 88 square feet. All work areas are outside of the bed and bank of the Bus Canyon Creek channel that traverses the park. Access to the work area will be from Wrangler Road via the property owner’s driveway and Bridle Path Homeowner’s Association (BPHA) trail. Biological surveys will be performed before and periodically during work to identify and avoid sensitive biological resources, including nesting birds. No mature trees will be removed. A Final Program Environmental Impact Report (EIR) on Environmental Protection Measures for the Ongoing Routine Operations and Maintenance Program was prepared in May 2008 (State Clearinghouse No. 2002091107). All applicable Best Management Practices described in the EIR and subsequent regulatory permits will be used for the proposed project