Cobourg Drinking Water System Master Plan: Overview

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Background
Lakefront Utility Services Inc. (LUSI) has engaged CIMA+ to prepare a Water Master Plan for the Town of Cobourg’s drinking water system (DWS). In development of the Cobourg DWS Master Plan, existing water treatment, storage, and pumping and distribution system infrastructure was evaluated in terms of its capacity to meet existing and future demands, as well as its condition. Based on analysis of the existing water system elements, the Master Plan presents recommendations for water infrastructure upgrades that will support the current and fully built-out (long-term) water demands of the Town of Cobourg.

Population and Demand
The Cobourg DWS currently services an estimated residential population of approximately 21,000 people and 285 hectares (ha) of developed Institutional, Commercial, and Industrial land. The average daily water demand generated by the current users is typically 9,000 m3/day. Approximately 65% of the demand is generated by residential customers with an average per capita demand of 282 L/day for each person. The balance of the average day demand is associated with institutional, commercial, and industrial users. The figure below illustrates existing population, development, and water demand.


Existing Population, Development and Water Demand

At full build-out of the land within the current urban (Municipal) boundary it is expected to have a total population of approximately 39,000 plus an additional 190.5 ha of developed institutional, commercial, and industrial land. On this basis, the projected average daily water demand at full build-out is 16,200 m3/day.

Most growth in the Town of Cobourg is expected to occur east of Brook Road North and north of the CNR and CPR corridors on lands referred to in the Town of Cobourg Official Plan as the Cobourg East Community.

Existing Infrastructure
The current Cobourg DWS infrastructure is comprised of the Cobourg Water Treatment Plant (WTP), the Victoria Street Zone 1 Elevated Tank (water tower), the Strathy Road Zone 2 Elevated Tank (water tower), and the Ewart Street Booster Pumping Station (BPS) as well as 170.5 km of trunk and local watermains (pipes).

To ensure appropriate water pressures across the community, the Cobourg DWS is divided into two pressure zones (Zone 1 and Zone 2):

  • Zone 1 encompasses the lower elevation areas in the southern portion of the Town. Water is pumped into Zone 1 by the high-lift pumps at the Cobourg WTP. The reservoir at the WTP and the Zone 1 Elevated Tank on Victoria Street store treated water for use in Zone 1.
  • Zone 2 encompasses the higher elevation areas in the northern portion of the Town. Water is pumped into Zone 2 by the booster pumps at the Ewart Street BPS. The Zone 2 Elevated Tank on Strathy Road stores treated water for use in Zone 2.


Existing Town of Cobourg DWS Infrastructure

Infrastructure Needs
Initial conclusions reached through the Master Plan process identified the following needs and recommendations for water infrastructure in the Town of Cobourg to support water demands in the near-term and at full build-out of the current urban (Municipal) boundary.

The Figure below provides a schematic illustration of the future Cobourg DWS at full build-out of the current urban boundary to service a population of 39,000 people.

Schematic of Future Cobourg DWS at Full Build-out

Water Treatment
Based on the Master Plan growth and demand projections, the current rated capacity of the existing Cobourg Water Treatment Plant (WTP) is sufficient to support full build-out of the Town of Cobourg. However, while there is no need for capacity expansion, investments will be required to ensure that the existing WTP (built in the 1970s) can continue to operate reliably up to its full rated capacity of 36,368 m3/d.

The most significant requirement for investment at the WTP is the rehabilitation or replacement of the existing clarifier (part of the treatment process). This is a priority in the next 5-10 years given the age of the clarifier and the fact that operation of the WTP is dependent on only a single clarifier. Based on an evaluation of options, the Master Plan recommends that the existing circular up-flow clarifier be replaced with new clarification process facilities located on the WTP site, with the new clarification facilities consisting of several parallel process units/trains to provide greater redundancy up to the WTPs current rated capacity.

Additionally, the Master Plan identifies a range of other ongoing repairs, improvements, and upgrades at the WTP that include:

  • repair and replacement of existing equipment and systems as they approach the end of their useful life;
  • improvements to equipment and processes to meet changing environmental and regulatory conditions; and
  • upgrades to ensure that there is sufficient redundancy for the WTP to operate effectively to meet increasing demands.

Treated Water Storage

The Master Plan identifies the need for additional floating storage (i.e. water tower capacity) for Zone 1 in the near-term and treated water storage for Zone 2 in the longer term. Recommendations for the provision of additional treated water storage in the Cobourg DWS presented in the Master Plan include:

  • a new Zone 1 Elevated Tank to replace or augment the existing Zone 1 Elevated Tank (within 5 years);
  • two (2) new Zone 2 At-Grade Tanks (in the long-term as growth occurs); and
  • Provision of new treated water storage at the Water Treatment Plant (long-term) or rehabilitation of the existing Zone 1 Elevated Tank (near-term).

Pumping
The capacity of the high lift pumping station at the Water Treatment Plant is adequate to support projected growth to full build-out. However, the expected population growth in Zone 2 of the Cobourg DWS creates a need for additional booster pumping facilities to support increased demand within the next 5 years, as well as a longer-term need for additional booster pumping capacity to support full build-out of Zone 2 and ultimately a new Zone 3. Recommendations for the provision of additional pumping infrastructure in the Cobourg DWS presented in the Master Plan include:

  • a new booster pumping station located on the same site as the new Zone 1 Elevated Tank and providing additional firm rated pumping capacity of 120 L/s as well as additional redundancy in the near-term;
  • expansion of the existing Ewart Street Booster Pumping Station to provide total firm rated pumping capacity of 312 L/s in the long-term; and
  • a new Zone 3 booster pumping station to service the highest elevation areas in the Cobourg East Community.

Distribution System
The Master Plan process evaluated the existing water distribution infrastructure (watermains) to:

  • estimate the short-term and long-term annual funding targets necessary to maintain the distribution piping;
  • identify upgrades necessary to improve redundancy, mitigate areas of problematic high or low pressure and improve fire flows; and
  • recommend locations for the provision of new trunk and sub-trunk watermains to support growth and development.

These recommendations will help to guide LUSI’s capital programs for the renewal and replacement of existing watermains and provide the basis for coordinating the planning and design of new watermains within future residential and non-residential developments.

Further Studies and Next Steps
The findings of the Cobourg DWS Master Plan will help to inform future updates of the capital works programs that form the basis of the Development Charge Background Study & By-laws as well as the Water Rate Study & By-laws.

Certain projects recommended in the Master Plan, such as new water storage facilities and new pumping stations that are not located on existing municipal servicing sites as well as new watermains that are located outside of existing road allowances, will require project specific Schedule B Municipal Class Environmental Assessments (MCEAs) before the projects can be implemented. Future MCEAs will build on the recommendations of the Master Plan to confirm the preferred site locations identified in the Master Plan while establishing in greater detail mitigating measures that may be required to prevent impacts to the surrounding environment.

Public Engagement
A public presentation will be held to present the Master Plan content recommendations on Wednesday, May 26, 2021 at 6:30 p.m. The public presentation is scheduled to be held through the Zoom Web & Conferencing platform and will consist of a 30-minute presentation, followed by a Question and Answer period.

A link to join the online presentation via Zoom Video Communications will be posted at https://engagecobourg.ca/water-master-plan

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