City of Toronto Watermain Rehabilitation Program

The City of Toronto Watermain Rehabilitation Program has been delivering Cured-in-Place-Pipe (CIPP) Watermain Structural Lining and Cathodic Protection of existing watermains for several years. In 2015, WSP was retained by the city to provide engineering design, project management, and contract administration services for the program.

WSP has worked closely with the city, contractors, and the public to ensure the successful delivery of the program each year. During WSP’s first contract with the City (2015-2017 program years), the Watermain Rehabilitation Program renewed approximately 525 km of watermain, making up 9.5% of the city’s 5,550 km watermain distribution network. Under its present assignment, WSP will continue to manage the delivery of this program until 2020.

WSP was also retained by the City of Toronto for the project management, design and construction administration of cast iron transmission watermain rehabilitation.

Learn about trunk watermain lining

Cured-in-Place-Pipe (CIPP) Watermain Lining is a method of watermain renewal achieved through the installation of a lining on the interior of existing aging watermains. First, the interior of the watermain is cleaned using any number of tools, including high-pressure washing and scrapers to remove any existing linings, tuberculation, and buildup to create a smooth surface. The liner, composed of either an unreinforced or glass reinforced felt tube, is impregnated with a thermos-setting resin and inserted into the existing watermain. Following installation, the liner is cured using hot air or hot water until hardened.

Water service connections are robotically re-instated from the interior of the pipe, or by tapping a new service from the exterior. In addition to laboratory testing of liner samples, the liner quality is inspected using CCTV camera and any deficiencies are removed and replaced. All valves, hydrants, and sub-standard water services are replaced as part of the work, resulting in a renovated water system.

The rehabilitated watermain is designed to last 50 years.

Cathodic Protection is used to prevent corrosion of existing Cast Iron watermains. This is achieved through the installation of sacrificial anodes along the watermain, which transforms the watermain from an anodic to a cathodic material. Cathodic Protection is intended to halt the deterioration of the pipe material and extend the life of the watermain by 5-10 years. When the anodes have been consumed, the process can be repeated. The cathodic protection process does not improve an existing watermain but rather keeps an already healthy watermain in a state of good repair. Metallic watermains experiencing low break rates can make suitable candidates for cathodic protection.

Compared to traditional watermain replacement, the use of CIPP and Cathodic Protection are cost-effective and less invasive solutions to watermain renewal due to the minimal excavations and reduced impact on the roadway. Additionally, more efficient design and planning results in a faster turnaround from identification of the watermain to the completion of rehabilitation, making this solution ideal for emergency situations.

The minimal design effort, and reduced $/m allows for a larger quantity of watermains to be renewed through rehabilitation than through replacement annually.

WSP has demonstrated innovation through the following initiatives:

• Development of a comprehensive communications strategy and database to respond, record, and manage all program communications with the public. The Communications Management Dashboard (CMD) is a GIS-based program which allows all enquiries to be geo-tagged and updated as the issue is resolved. This program also provides data to predict trends in community involvement for upcoming works.
• Implementation of digital daily reporting. For a program delivery model with tens of active sites at any given time, the digital daily reports have reduced end-of-month negotiations with contractors regarding payments and the database allows the client to access the most up-to-date financial data for all project sites.
• Continued development of CIPP specifications based on findings from liner test results and information gathered through the Quality Assurance/Quality Control review of the thousands of kilometers of rehabilitated watermain.