CEI provided design, bidding, construction administration and field inspection services to the Town of Merrimac for the implementation of three new pressure zones within its water distribution system. These three distinct areas of Town were historically plagued by low service pressures due to high ground elevations; as a result, the Massachusetts Department of Environmental Protection mandated that the Town implement infrastructure improvements to increase service pressures in these areas. Based on an evaluation of mapped ground elevations and the water distribution system (pipe network and tank location), CEI established the boundaries of the three new pressure zones and locations of the associated booster pump stations and pressure reducing valves.
Each pump station was designed with the following features and considerations in mind: multiple pump arrangement with variable frequency drives to provide the full operating range from minimal domestic water flows up to fire flows, automated PLC based controls to maintain a stable discharge pressure setpoint, radio telemetry to connect these remote facilities into the Town’s SCADA system and integrated emergency generators (LPG fueled) located within the building for ease of maintenance and blending of the facilities within residential areas. Two of the pump stations have a duplex pump system while the third station has a triplex pump system, corresponding to the required fire flows for the respective pressure zone.
CEI designed and located pressure reducing valve vaults for each of the pressure zones, due to the varying terrain within each pressure zone (preventing low elevation areas from becoming over-pressurized) and to maintain hydraulic looping throughout the distribution system to eliminate any concerns with water quality and flows to other areas of the distribution system. Since these pump stations have been placed online, the service pressures and associated flows in these areas have significantly improved to the benefit of existing customers and to the benefit of additional development within previously undevelopable areas of Town.