Cochichuate Aqueduct Sanitary Sewer Rehabilitation
The City of Newton selected Weston & Sampson to perform an inventory of conditions on the Cochituate Aqueduct. The Cochituate Aqueduct is a 26,036 linear foot sanitary sewer interceptor in service since 1952. The purpose of the project was to document the existing condition of the interceptor and interceptor manholes, perform a hydraulic capacity analysis, and provide recommendations for repairs. We identified hydraulically limiting pipe segments, a section of 48-inch reinforced concrete pipe severely deteriorated by hydrogen sulfide, and several other pipeline and manhole defects.
The city subsequently selected Weston & Sampson to design rehabilitations, prepare plans and specifications, and provide construction engineering services for the rehabilitation of the defects. The design focused on the installation of a 1,015 linear foot, 48-inch, cured-in-place liner. The project included:
- 1,015 linear feet of 48-inch CIPP
- Bypass pumping plan
- Access to work site plan
- Hydrogen sulfide monitoring
- Rehabilitation of three sanitary sewer manholes
- Cutting of one protruding service connection
- Installation of one permanent ultrasonic flow meter
- Design and installation of the 48-inch cured-in-place liner was particularly challenging for the following reasons:
- Weight limits associated with bringing the liner to the site
- Long length between manhole access (approximately 2,000 linear feet)
- “Blind shot” liner installation (i.e., liner installation did not terminate at a manhole)
- A 1,400 linear foot road was constructed to provide access to the installation manhole
- Bypass pumping of up to 6.0 million gallons per day (mgd)