Saanich sold on water distribution system renewal planning
As defined in Developing a Water Distribution System Renewal Plan—a best management practice created for the Ministry of Health by the BCWWA—water distribution system renewal planning (often called asset management) optimizes the life-cycle value of a utility’s physical (infrastructure) assets through effective maintenance, rehabilitation, and replacement programs.”
Developing a Water Distribution System Renewal Plan outlines two complementary approaches—top-down and bottom-up. “The top-down approach is used for strategic long-term planning of policies and programs whereas the bottom-up approach is used for short-term capital planning of projects.”
The National Water and Wastewater Benchmarking Initiative’s Issue Paper on Infrastructure Reinvestment recommends that utility managers answer the following six questions before making asset reinvestment decisions:
- What do you own?
- What is it worth?
- What is the deferred maintenance?
- What is its condition?
- What is the remaining service life?
- What do you fix first?
The answers, when reflected in an appropriate performance management model, will ensure an effective and affordable water distribution system.
Developing a Water Distribution System Renewal Plan recommends “renewal plans be reviewed every five to ten years to reflect the current condition of the system as well as the effectiveness of various renewal technologies. Municipalities should track water main break rates, water quality problems, fire flow rates, and leakage rates to establish deterioration rates and the adequacy of the program.”
The District of Saanich is among the 30 percent of utilities surveyed that have developed and implemented water distribution system renewal plans. Of the remaining utilities, 44 percent are considering one for the future.
The District of Saanich services almost 30,000 connections, with a distribution system that dates back to 1875. It was ripe for renewal planning given the aging infrastructure, premature failure of asbestos cement mains, and high operations costs associated with repair of ruptured mains. The district needed to develop a proactive approach to system renewal.
A formal planning strategy was initiated in 1997; a ten-year capital works program was developed for 1998 to 2007 to address the highest priority replacements. The prioritized replacement strategy considers the following:
- existing system deficiencies (e.g. fire flows, residual pressures, water quality);maintenance and break history;
- coordination with other infrastructure improvements;
- premature failure of asbestos cement pipe (100 to 200mm diameter);
- environmental vulnerability due to water main breaks (e.g. risk of chlorinated water entering a natural water course).
Given that Saanich has more 541 km of water main, the cost to replace the entire system is estimated at $260 million. The current plan focuses on replacement of the highest priority projects utilizing available funding of about $2.2 million per year. Funding for water system replacement is increased by about two percent per year.
Challenges faced by Saanich included lack of data in digital format (e.g. pipe inventory, pipe network drawings and a distribution system computer model), and lack of funding to address needs. The advantages, however, far outweigh the challenges. A systematic approach to main replacement will allow coordination with replacement of other infrastructure, reduced maintenance costs, and improved water quality.
District staff certainly learned a thing or two about renewal planning along the way. Here’s what they recommend to utilities embarking on a renewal planning process.
- Develop a computer model of the water distribution system, and use that model to determine system deficiencies and model replacement facilities.
- Conduct field-testing of your system to calibrate the model and provide data for a condition assessment.
- Use GIS tools to analyze condition, age, break history, environmental risk and coordination with other infrastructure work.
- Develop a spreadsheet-style pipe inventory and costs analysis system.
- Use an integrated approach with road, sewer, drain, and water system renewal.
For more information contact Jas Paul at 250-475-1775 or PaulJ@saanich.ca