ADMINISTRATIVE REPORT

Date: February 16, 1998

Author/Local: B.Crowe/7368

CC File: 3206

TO:		Vancouver City Council
FROM:		General Manager of Engineering Services
SUBJECT:		Proposed Transfer of Rechlorination Stations to the Greater Vancouver Water District

RECOMMENDATIONS

A.THAT the General Manager of Engineering Services be authorized to negotiate and enter into an agreement, to the satisfaction of the Director of Legal Services, with the Greater Vancouver Water District to transfer the ownership, operation and maintenance of the Chilco & Alberni and the Boundary & Eton rechlorination stations to the Greater Vancouver Water District.

B.THAT, subject to the above agreement and appropriate City of Vancouver permits, the Greater Vancouver Water District modify the Chilco & Alberni and the Boundary & Eton rechlorination stations so that they will feed into District mains, upstream of their present feed points.

C.THAT the City decommission its Bridgeway & Skeena rechlorination station after the District begins operation of the modified Boundary & Eton station.

D.THAT Engineering Services reduce its Waterworks Operating Budget by $144,000 per year when the City of Vancouver stops operating the stations.

COUNCIL POLICY

There is no Council policy applicable to this report.

PURPOSE

This report explains changes to the City of Vancouver’s rechlorination program which will result from the Greater Vancouver Water District’s (GVWD’s) Drinking Water Treatment Program, and recommends transferring responsibility for two of Vancouver’s stations to the GVWD. The report precedes a similar report which will be presented to the GVWD Water Committee on March 13, 1998.

BACKGROUND

The City of Vancouver owns and operates three rechlorination stations which increase the chlorine concentration in portions of the City’s water distribution system. These stations are located at Chilco & Alberni, the main transmission feed into Vancouver’s downtown core, and at Bridgeway & Skeena and Boundary & Eton, two major feed locations from the District’s Second Narrows crossings (Figure 1). Together, these stations provide improved chlorine residuals to about one quarter of the City.

The Chilco & Alberni station was constructed in 1986. Boundary & Eton and Bridgeway & Skeena were constructed in 1988 and 1989 respectively. All three stations treat water from the District’s Capilano source, which typically exhibits the most frequent turbidity problems and associated water quality concerns.

At the time of construction, it was envisioned that several more stations would be constructed to serve the remainder of Vancouver. Vancouver’s chlorination station construction program was subsequently put on hold while the District’s Drinking Water Treatment Program (DWTP) was under development. This postponement was necessary because it was unclear what form of secondary disinfection the District would implement, and where their stations would be located.

After extensive public consultation and design reviews, the District selected chlorination for its secondary disinfection program. They began construction of their first five rechlorination stations in 1997. One of those stations is located in Vancouver, at Kersland Reservoir in Queen Elizabeth Park, and became operational on February 9, 1998. As part of the design of the first five regional stations, the District reviewed which portions of their system would still require supplemental chlorination. For two of those areas, existing City of Vancouver stations could be modified to function as District facilities, rather than constructing additional District stations.

DISCUSSION

City staff have worked closely with the District to develop this proposal, investigating the pros and cons for both organizations and comparing the proposal with the alternative of the District building new facilities of their own. We believe that the best option for both organizations is to transfer and modify two existing Vancouver stations, and to shut down Vancouver’s third station at Bridgeway & Skeena. The rationale for each station is as follows:

Chilco & Alberni:

The Chilco & Alberni rechlorination station presently feeds the City’s downtown distribution grid, through a pressure regulating valve (PRV) station at the same location. These PRV’s reduce the pressure from the GVWD’s First Narrows Crossing (Capilano No. 4 Main), which is located immediately outside the station and carries on to feed much of the west side of Vancouver and the University Endowment Lands. GVWD engineering investigations indicated that the western portions of Vancouver and the UEL which are fed by this main will require additional chlorination, and this could be provided at Chilco & Alberni if the station is modified to feed into the District transmission main rather than Vancouver’s PRV station.

This proposal has the following benefits:

·Lower cost - The construction cost to convert the existing station would be less than half the cost to construct a new station further downstream. In addition, property acquisition at other suitable locations in Vancouver would be difficult and expensive, and may face public opposition. Operating and maintenance costs would also be assumed by the GVWD.

·Improved service to Vancouver - By injecting into the District mains, upstream of Vancouver’s present injection location, Vancouver would receive secondary disinfection benefits throughout a much greater area. An estimate of the additional area which would receive adequate chlorine residuals is shown in Figure 2.

·Best use of existing facilities - This proposal would make greater use of the existing station, rather than the District building another station to achieve similar effect. Also, any alternative location for the District station would serve less of Vancouver, and could require the City to construct an additional station of its own to provide the coverage which the modified Chilco & Alberni station will provide.

Boundary & Eton:

Vancouver’s second rechlorination station is located above Hastings Park at Boundary & Eton. This station treats water from the District’s Capilano Main No. 7, which crosses at Second Narrows. The District has identified the need to improve its disinfection in this main, to serve portions of Vancouver and Burnaby. Similar to the Chilco & Alberni station, the District proposes to relocate the chlorine injection location onto the District main upstream of the station.

This proposal has the following benefits:

·Lower cost - The proposal results in a capital cost saving of about $60,000 compared to building a new station (the construction cost savings are less dramatic at this location because the modifications to the station are more expensive than at Chilco & Alberni). The District would also assume the operating and maintenance costs.

·Best use of existing facilities - If the District constructs a new station elsewhere, it will be upstream of the Boundary & Eton station and render the existing station redundant.

The resulting coverage area in Vancouver (also shown on Figure 2) will not change, although the Bridgeway & Skeena station would no longer operate, as described below. A comparable area in Burnaby, which was not previously treated, would be downstream of the new District injection location and receive treatment.

Bridgeway & Skeena:

Vancouver’s third rechlorination station is located at the south end of the Second Narrows Bridge, at Bridgeway & Skeena. This station, like Boundary & Eton, treats Capilano water that is supplied to Vancouver from the District’s Second Narrows crossings, but it feeds into different City transmission mains than the Boundary & Eton station does. However, whether the District modifies the Boundary & Eton station or builds a new station, the new District chlorination points will be upstream of both transmission mains fed by the existing stations. As a result, the Bridgeway & Skeena station will no longer be required, and it will be decommissioned. City staff will explore salvage opportunities for the existing equipment, or the equipment will be stored for use in future City or District facilities.

Financial Impact:

The total operating and maintenance (O&M) costs for the three City rechlorination stations are $144,000 per year. Once the modified stations are operational, the City would shut down its Bridgeway & Skeena station, and our O&M funding would no longer be required. These savings would be realized in 1999 or 2000 (and thereafter), depending on implementation schedules.

Through our water purchases from the District, the City would contribute to the capital improvements at each station. However, if the District did not modify Vancouver’s stations, they would need to construct new stations for an estimated cost of approximately $600,000 more than the proposed station modifications, or an additional City cost of approximately $180,000. Also, the City would have to continue operating Chilco & Alberni, and could have to build additional stations which would not be required with the proposed transfer. Therefore, the cost savings for both the City and the District are substantial if the two existing stations are modified and transferred to the GVWD.

The District proposal is contingent upon the City transferring the rechlorination stations to them for the sum of one dollar. Their reasons for this condition are as follows:

·At Chilco & Alberni, they believe that the financial (operating cost) and functional (service area) benefits are greater for Vancouver than for the District.

· At Boundary & Eton, the capital cost benefit of modifying the existing station, rather than building a new one, is relatively small (6%), and the modified station will be more difficult to operate because it is further from the injection location than a new station would be. Therefore, if the District must pay an acquisition cost for the existing station, the proposal is not economically viable.

City staff are willing to accept this condition because we recognize that the District would otherwise need to build stations in locations that are less beneficial to Vancouver and would be more costly for Vancouver and regional taxpayers. As a result, staff recommend that we proceed with transferring and modifying the stations as described in this report.

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(c) 1997 City of Vancouver