Thorn Creek Basin Inserting Linear Material
Thorn Creek Basin Bypass Pumping
Thorn Creek Basin, CMT Staff Conferring with Stakeholders
Regional Trunk Sewer Rehabilitation
CIPP (Cured in Place Pipe) Sewer Rehabilitation
Crawford, Murphy & Tilly (CMT) was asked to provide an independent review of the trunk sewer inspections and offer an opinion about the condition of the sewers. Once the condition was evaluated and deterioration determined to be worse than previously thought, the Thorn Creek Basin Sanitary District asked CMT to prepare construction documents to rehabilitate the most critical sewers. With the District boundaries encompassing multiple jurisdictions and highway authorities, the challenge was to quickly work with the local communities and regulators to minimize traffic inconvenience and service disruptions to residents.
- Establish guidelines for review and assessment of the trunk sewers based on PACP data, as well as the pipe diameter, depth and location.
- Spread the CCTV inspection video and report review among multiple staff engineers to quickly identify the true sewer conditions.
- Determine which sewers require rehabilitation in the near term versus those that could wait until the next 5 year inspection cycle.
- Develop construction documents to install cured-in-place-pipe (CIPP) in the sewer segments in greatest need of rehabilitation.
- Evaluate alternatives for bypass pumping to identify feasible options for contractors to consider during bidding.
- Initiate the permitting process with highway authorities and local governments so contractors could prepare bids to line the sewers.
CMT prepared construction documents and permit applications to rehabilitate 2.7 miles of trunk sewer ranging in diameter from 18” to 48”. Flexibility was incorporated into the construction documents to accommodate the contractor’s bypass pumping plan and finalizing the necessary permits. Construction started in 2017 and finished in 2018, with CMT providing Resident Project Representative services.