Case Study - Crystal Beach, City of Ottawa: Two Watermain Rehabilitation Techniques on One Project - City of Ottawa

The new City of Ottawa, now composed of the Region of Ottawa-Carleton and 11 neighbouring communities has a water distribution system servicing a population base of over 750,000 people. The Region of Ottawa-Carleton had owned and operated the water distribution system in all 11 municipalities since 1969. The potable water systems inventory consists of approximately 2,500 km (1,600 miles) of watermains, 24,000 valves and 14,000 hydrants. The age of the system varies significantly from a very old system, dating back to the 1870s in the core area to relatively new piping in the communities of Kanata, Nepean and Gloucester. The replacement value of the potable system has been estimated to be in excess of $1.5 billion ($1 billion US). The new City's annual budget for conventional watermain replacement is approximately $40 million dollars ($26 million US). Through various methods of investigation, it has been noted that failure due to external corrosion is not as severe on the cast iron pipes. Nevertheless, as the older cast iron mains were unlined, the interior walls of the pipes have been subject to internal build up due to internal corrosion, known as tuberculation, which significantly reduces the hydraulic capacity of the watermains as well as creating "red" problems.