A3 ADMINISTRATIVE REPORT Date: January 17, 1997 Dept. File No. 1.40.97.01 C.C. File: 5809-1 TO: Vancouver City Council FROM: General Manager of Engineering Services SUBJECT: Watermain Flushing Program RECOMMENDATION A. THAT the water main flushing program be significantly increased with a goal of flushing all water mains of less than 16 inch diameter annually. B. THAT the 1997 waterworks operations budget be increased by $210,000 to accommodate the new program and that an additional $24,000 be allocated for equipment expenditures in the first year, all of which will be funded through water rates. C. THAT Council request to the GVWD Board that the City receive a credit for the water used in this program. D. That Engineering Services report back to Council after completion of the 1997 program with results and proposed refinements. COUNCIL POLICY In October 1990, Council approved in principle the GVRD Drinking Water Quality Improvement Plan. On Sept 24, 1996, Council approved the 1997-1999 Waterworks Capital Plan, which includes the strategy that Drinking water quality is addressed through a combination of City and District programs, with the City cooperating in the implementation of the GVWD Water Quality Improvement Program . - 2 - PURPOSE This report proposes that the City increase its current flushing program to improve water quality by reducing bacterial regrowth, as part of City and Regional water quality improvement initiatives. BACKGROUND The waterworks distribution system of the City of Vancouver operates on a utility basis, with the City purchasing water from the Greater Vancouver Water District (GVWD) supply system and distributing it to water consumers within the City on a cost-recovery basis, including debt charges. Cost recovery is through metered and flat rate water fees. A June 1996 consultant report prepared for the GVWD urges member municipalities to give increased funding priority to flushing and cleaning of the water mains on an annual basis to aid the effectiveness of secondary disinfection . Cleaning watermains through flushing is a key element to maintaining good water quality in the distribution system. Flushing consists of isolating a watermain from the distribution grid and flushing water through it by opening one or more fire hydrants. By flushing the mains, most sediment and some tuberculation (corrosion buildup) is removed, removing bacteria and reducing the surface area where bacteria regrow. This allows the disinfectant (chlorine) to work more effectively and last longer, improving water quality. DISCUSSION The existing City flushing program sees flushing conducted in areas where water quality becomes a concern. These areas are identified each year through our water quality monitoring program. Flushing is also done in response to dirty water complaints, and on dead-end mains as crew time permits. The 1996 annual flushing budget was $110,600. This program results in approximately 2 percent of the water system being flushed annually. With the implementation of its Drinking Water Treatment Program, the District is now strongly urging all member municipalities to regularly flush their entire water distribution systems. The District feels that the success of their treatment improvements depends upon clean municipal distribution systems. Without watermain cleaning, bacterial regrowth is expected to be an ongoing problem. - 3 - In Vancouver, widespread watermain cleaning will require a significant increase in the resources allocated to this task, adjustments in methods so that larger areas can be flushed more quickly, reallocation of existing funding from other programs, and increased overall operating budget funding. In an attempt to develop a comprehensive proposal, staff have carried out a pilot program in the fall of 1996. The proposed 1997 program is based on our knowledge and experience gained through the fall pilot program. We will report back to Council after completion of the 1997 program with the results and any proposed refinements. The flushing program would be conducted at night to minimize water quality impacts as well as disruptions to neighbourhood areas due to large volumes of water in the street. Due to possible freezing temperatures in the winter, and water conservation initiatives in the summer, the proposed annual flushing program would be conducted in March, April, May, October and November. The flushing program will include all watermains in the City distribution system 16 inches in diameter and smaller. Larger diameter watermains are not included in this program as the quantity of water required for an effective flush is prohibitive. These mains would typically be pigged (mechanically cleaned), although much less frequently. Six two person crews would be required to conduct the program, along with one Foreman to organize and supervise. In addition, one person chlorine crews would be used to add chlorine on a trial basis in some areas of the City with little or no chlorine residual. Water from each flush is disposed of through the City s combined sewer system, which is generally treated at the Iona Island Sewage Treatment Plant. In those areas where the storm sewers drain into local waterways, the water will be either dechlorinated before disposal, trucked to areas where the storm sewer leads to the City sewage treatment facility, or disposed through the sanitary sewer system. FINANCIAL IMPLICATIONS Equipment Costs One time costs for the acquisition of chlorine equipment and metering kits, turbidity kits, hose and appurtenances for this program are estimated at $24,000. These costs are to be recovered from the 1997 water operating budget. - 4 - Program Annual Costs The total estimated cost of the proposed program is $402,000 for 1997. The General Manager of Engineering Services recommends that this be funded through a combination of existing watermain flushing funds, reallocating portions of other existing waterworks operational funding, and some increased funding. Although the cost estimate is based on the pilot program implemented in the fall of 1996, we have not previously carried out a flushing program on the scale proposed. Our ability to complete the program at the estimated cost will be dependent on a number of factors including the productivity we are able to achieve on a program of this size, and the need for chlorination and dechlorination as a part of the flushing process. We will report on the success of this program and the need for any budget adjustments to meet the goals of the program after completion of the 1997 program. Many water main valves and some fire hydrants will be operated during the flushing procedure. The City currently inspects and repairs all main valves, and fire hydrants regularly. By combining the two processes, inspecting and noting deficiencies on any hydrants and valves operated while flushing, some efficiencies can be realized. It is therefore proposed that the following operating budgets be reduced and the resulting available funds be added to the flushing program: Waterworks Budget Item 1996 Budget Reduce By Repair and Maintenance Hydrants 299,800 20,000 Valve Inspection Routine Maintenance 541,800 60,000 Total 80,000 In 1996, our watermain flushing budget was $110,600. When combined with the above reallocations, the resulting net increase required in the 1997 Waterworks Operations Budget would be $210,000. On November 26, 1996, Council reviewed and approved the proposed water rates for 1997. These rates included an allowance for a $200,000 funding increase to accommodate increased watermain flushing, subject to Council s review of today s report. The slightly higher proposed increase would not alter the 1997 water rates. - 5 - This funding is probably not adequate to flush the whole system annually, but frequency will improve as secondary disinfection is implemented throughout the rest of the City (decreasing the need for chlorination during flushing) and as the condition of the system improves with repeated cleaning and better source water treatment. RELATED ISSUES Water Cost In addition to the program operating funds, a significant amount of water will be consumed for this flushing program, which must be purchased from the GVWD. The estimated water cost is $225,000 at 1997 rates. This cost is not reflected in the estimated program costs. It will be reflected in increased water purchase billings from the GVWD. It is proposed that Council request to the GVWD Board that the City receive a credit for the water used in this program. If the credit is not received, these water costs will be reflected in an increased water purchase from the GVWD, which can be funded from the Water Rates Stabilization Reserve for 1997, and from the water rates in future years. The GVWD is asking municipalities to cooperate in their Water Quality Improvement programs by increasing their flushing programs. It would be reasonable for them to support the efforts of those municipalities that participate in this effort by not charging for the water used. Sewage Treatment Costs Most of the flushed water will be treated at the sewage treatment facility at Iona Island. Because the flushing program does not run during the driest months when the lowest sewage flows are usually recorded (the City pays for sewage treatment based on the lowest 25th percentile of flows), there is little chance of a significant impact on sewage treatment costs. ENVIRONMENTAL IMPLICATIONS Flushed water will be disposed of via the existing street stormwater or sanitary sewer system. For the vast majority of the City, this water will be treated at the Iona Island Sewage Treatment Plant. In those areas where chlorinated water would be discharged directly to marine habitat, flushed water will be dechlorinated before entering the stormwater system, discharged to the Sanitary Sewer, or trucked to an area that receives treatment. There should be no negative effects on the environment. * * * * *