CIMA+ wins a Gold Award of Merit from the Grand River Chapter of ACEC-Ontario for the Paisley Pumping Station Upgrades for the City of Guelph

CIMA+ has won a Gold Award of Merit in the Water & Wastewater category from the Grand River Chapter of ACEC-Ontario for our design and construction services for the Paisley Pumping Station Upgrades, completed for the City of Guelph. The upgrades almost double the capacity of the pumping station and allow much-needed residential development within the city to proceed. A comprehensive, carefully sequenced construction staging plan allowed for the construction and commissioning of the upgrades without any interruption of services to users or any increase in the footprint of the facility.



The City of Guelph currently provides municipal utility services to nearly 136,000 residents. By 2051, in alignment with provincial growth projections, the number of residents using municipal services is expected to climb by close to 50% to over 200,000, and by significantly more not long after when density targets are achieved in strategic growth areas of the city. To accommodate the future service demand, and to maintain the reliability of the supply, the City is investing considerably in its municipal services, including its drinking water system.

Upgrades to the Paisley Pumping Station are an important part of the City’s long-term water-supply plan. The City’s distribution system is divided into two pressure zones. Pressure Zone 1 services most of the city and contains the majority of the groundwater supply wells. Pressure Zone 2, located in the northwest corner of the city, is fed water from Zone 1 by the Paisley Pumping Station, the main pumping station transferring drinking water from Zone 1 to Zone 2. Several of the city’s designated intensification corridors and community mixed-use nodes, which are strategic growth areas with higher residential and employment densities, are located in Zone 2.

The station was originally constructed in 1976 and the pumps, mechanical and electrical equipment had reached the end of their service lives. The City retained CIMA+ to complete the preliminary and detailed design and contract administration and inspection services.



Overhaul of the station following a comprehensive construction staging plan

The project had four main objectives related to increasing the capacity, reliability and flexibility of the system:

  • Buildout of the supply to meet the City’s projected 2051 needs by increasing the station’s firm capacity from 265 L/s to 480 L/s through upgrade of the two pumping systems: vertical turbine (VT) pumps that draw from the reservoir and horizontal inline split-case (HI) pumps that boost pressure directly from Zone 1 to Zone 2
  • Replacement of infrastructure and equipment that is at the end of its service life to improve reliability and protect against obsolescence
  • Installation of a second inlet connection to the station for increased operational flexibility in drawing from Zone 1 and to maintain flows to the station when maintenance is required
  • Ability to install a second outlet from the station to service a future watermain connection in Zone 2

Given the broad scope of the objectives, the project team made two determinations early in the design phase. First, the team concluded that to meet all project objectives, all mechanical and electrical equipment at the station needed replacement and that extensive civil works at the constrained site were necessary to enhance the supply capacity of the station. In addition, significant reconfiguration of the room layout was required to accommodate the increase in size and capacity of the equipment without change to the overall building footprint or loss in functionality and separations needed by Operations staff. The project team also determined that to overhaul the station, a comprehensive, carefully sequenced staging plan was required to coordinate design disciplines and ensure that the upgrades could take place without interrupting the pumping station operations. The plan was updated throughout the preliminary and detailed design phases as new conflicts and constraints were identified, with each stage planned and timed so that it satisfied all of the conditions required for the next phase.



Technical Excellence and Innovation

A fundamental requirement of the project was maintenance of the water supply from the system throughout construction. Insufficient redundancy in the system meant that the station could not be taken offline for the upgrades. Instead, it had to be kept in continuous operation except for limited shutdowns. This made the upgrades considerably more complex than an equivalent greenfield project in which the station could be constructed completely offline with unrestricted construction staging. Adding to the complexity of the design was the congestion of the space to be used for construction. The station was originally designed to maximize use of the interior floorspace for equipment and piping. Because the station’s footprint could not be expanded, all construction for the upgrades—including for the near doubling of the station’s capacity—had to be completed within the existing space, within a tight complex of pumps, piping, process and electrical equipment.

During the design phases, CIMA+ worked closely with the City and contractor, NAC Constructors, to create a twelve-stage construction sequencing plan around an eight-hour maximum shutdown period. At the time of construction, the City conducted a thorough review of the other water facilities and made operational accommodations and modifications to increase the shutdown window to a maximum of 24 hours. Ultimately, the upgrades were completed with no disruption to station operations outside of scheduled shutdowns, and none of the shutdowns exceeded the 24-hour time limit set by the City. In fact, only one full station shutdown was requested by the contractor and the work was completed in approximately 17 hours, ahead of schedule. Prior to a shutdown, the CIMA+ team used a system hydraulic analysis to verify that the supply system had 24 hours of reserve capacity. The general contractor also developed a contingency plan to return the original equipment to service if a problem occurred during an upgrade.

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