Town of Grand Bay-Westfield – Municipal Water System Feasibility Study
Note: The following is an excerpt from the Town of Grand Bay-Westfield Municipal Water System Feasibility Study dated May 2004 as performed by Godfrey Associates Ltd. If you are interested in reviewing the entire extensive document, it is available here.
The Town of Grand Bay-Westfield, with a current population of approximately 5,000, is entirely serviced with potable water by individual private wells. Lot sizes throughout the Town range from less than 0.20 acre to several acres. The current minimum lot areas are 0.17 to 0.23 acre for lots serviced with sanitary sewer and 1 to 3 acres for unserviced lots depending on the respective zones as defined by the Town’s Zoning By-Law. Given the topography of the local area and the predominantly shallow soil cover to fractured bedrock, the universal and effective treatment of sanitary wastewater is crucial to the preservation of groundwater quality. The former Village of Grand Bay, in recognition of this fact, initiated a central sanitary wastewater collection and treatment system in the mid 1970’s. Since that time the system has been extended as funding became available. Presently less than 50 percent of the entire Town of Grand Bay-Westfield is serviced by the wastewater system.
The completion of the wastewater system is considered essential in maintaining the status quo with regard to municipal potable water supply. Even so, many residents have experienced poor water quality due to contamination from sources such as septic tanks, road salt, and high mineral content. In addition, sustained residential growth in some areas may result in a gradual lowering of the water table, particularly in predominantly bedrock areas where recharge of groundwater reserves is limited.
The above issues and other related factors are crucial to long range planning for the protection and preservation of reliable and clean groundwater supplies, particularly if a partial or complete municipal water supply system is not within the long-term planning horizon of the municipality. The provision of clean drinking water is a basic fundamental human need rather than an optional service and therefore the adoption of a long-term strategy by municipal staff and council in this area requires due consideration of the potential long-term ramifications for public health and community growth.
The required maximum day capacity for a municipal water system to service the entire Town of Grand Bay-Westfield has been estimated at 1.2 million gallons per day based on current population and projected growth over a twenty-year planning period. This estimated capacity includes peak user demand and when combined with firefighting demand based on current design standards requires a total water storage capacity of approximately 4 megalitres. The total length of the pipe network required to service the entire Town is approximately 63 km with pipe diameters ranging in size from 150 mm to 300 mm. Largely due to the linear development pattern and low population density, the cost of the supply and distribution network is over 75% of the total cost of the entire system including supply, treatment, pumping, and storage. The extreme variation in topography from east to west across the community will require three pressure zones regulated by at least four booster pumping stations.
The requirements for pumping and water treatment are dependent on the water supply source ultimately selected. Based on the preliminary findings of this study, three options for water supply appear to be feasible as follows:
1. Groundwater Supply
Develop groundwater production wells in the Nerepis Valley area between Sunset Valley and Brittain Road. Based on the findings contained in the attached report by Fundy Engineering and Consulting Ltd., there appears to be good potential for developing high production wells within this general area. Existing water test data available from wells drilled within the area indicates that treatment for iron and manganese removal will probably be required. Based on the assumption that the wells are not under the direct influence of the Nerepis River, filtration avoidance may be possible with a double barrier disinfection system using UV radiation and chlorination. The total construction cost for a complete municipal water system based on the foregoing assumptions was estimated at $31,000,000.
2. Surface Water Supply
The adjacent St. John River was not considered a realistic surface water supply due to the lack of control over the watershed and the high cost of water treatment. A chain of lakes located west of the community offer excellent potential as surface water supplies particularly the largest lake known as Loch Alva. This lake lies within a protected watershed and, subject to receiving adequate water allocation, has a sufficient firm yield to supply the Town. A water transmission main could be constructed from Highland Road to the deeper portion of Loch Alva complete with parallel access road and power extension. Given sufficient water clarity, filtration avoidance may be possible using the same treatment option as described previously for groundwater. The total cost for the Loch Alva option including a deep water intake, pumping, and treatment was estimated at $33,000,000.
A variation of the Loch Alva option is feasible by constructing a transmission main parallel to Route 177 and 7 to the existing City of Saint John raw water lines from Spruce Lake. Based on a pumping and water treatment arrangement similar to Loch Alva, the total estimated cost of this option was estimated at $32,500,000. While very close in cost to the Loch Alva option, this option will probably require a user fee to the City of Saint John for the supply of raw water to the Town pumping station. In addition, the entire raw water capacity of the existing main may be totally allocated to industrial use in which case a further extension of the Town transmission main may be required to Spruce Lake.
At this point, it is important to note that some or all of the supply options described may require a conventional or modified water filtration plant to meet regulatory treatment requirements. This would increase the respective total construction cost by $5,000,000 to $10,000,000 depending on actual water quality and process complexity.
3. Regional Water System
The Water Strategy report for the City of Saint John proposes an eventual extension of water service to the southern Town boundary. The report also identified a potential modification to this proposal whereby the transmission and pumping capacity would be increased to supply the Town of Grand Bay-Westfield. This would reduce the Town water infrastructure to distribution, storage and booster pumping stations, the construction cost for which was estimated at $26,900,000. In addition to capital and operating costs, there would be a user fee to the City of Saint John for treated water which would most likely originate from the Loch Lomond supply with the Spruce Lake supply allocated to raw water for industrial use. This option is dependent on the ultimate implementation schedule adopted by Saint John for the extension of service to the Martinon area and is subject to the development of a mutually satisfactory financial and operating agreement between the municipalities and other funding partners.
In conclusion, there are currently at least three potentially feasible options for a water supply source for a municipal water system. The groundwater option is contingent on finding two or more high yield wells through an exploratory drilling program with suitable water quality. The suitability of all options is subject to Environmental Impact Assessment and the prospect for approval by various regulatory agencies will change as regulations are revised and the continuing development patterns adjacent to potential water sources continue to influence the perceived impacts.