Frequently Asked Questions

A Municipal Class Environmental Assessment is a study that will define the problem / opportunity, identify and evaluate alternative solutions, and determine a preferred solution in consultation with the City of St. Catharines, regulatory agencies, affected stakeholders and the general public.

City sewers collect sewage and discharge from properties and send flows to a Wastewater Treatment Plant where the wastewater contaminants are removed.

Combined sewers collect rainwater runoff and sewage in the same pipe. When it rains heavily, the combined sewers may be overwhelmed with the volume entering the system. 

CSOs are designed to relieve the system at certain points by storing or discharging untreated sewage into the environment. CSOs were historically used to relieve the system and reduce the risk of basement flooding. Modern sewer systems are designed with separate pipes for sewage and stormwater, eliminating the need for CSOs.

A PPCP is a long-term strategy to identify, investigate, and reduce untreated sewer system overflows to the environment. This study will identify actions to help manage the sanitary and combined sewer system to reduce overflows and reduce the risk of basement flooding.

Periodic review and assessment is needed to ensure the long-term sustainability of the City’s wastewater system. The City last undertook a major review of the wastewater system in 2008. As the city continues to change, it is important to check in on long-term plans often, to make adjustments for current needs and to check on progress.

Basement flooding due to sewer surcharging is typically the result of either a blockage in the sewer system causing water to backup or too much rainwater or snowmelt entering and overwhelming the sewer system resulting in sewer backups. Other factors can result in basement flooding such as overland flow or private property issues such as sump pumps or lateral blockages.

An objective of the study is to quantify existing overflows from the wastewater system to the environment and to identify cost-effective and sustainable solutions to manage and / or reduce overflows. Reducing overflows reduces any negative effects from untreated sewage overflows.

The study will assess how climate change may impact the future performance of the wastewater system. Climate change may impact the amount of rainfall runoff that could enter the wastewater system, this Study will consider how rainfall patterns may change in the future. Resiliency against the impacts of climate change will be considered in the development and evaluation of potential solutions.

This study will recommend future construction projects; no construction will be undertaken for this study.

The recommendations of this study will be used to inform the City’s future wastewater capital program and development charges, which are used to determine the City sewer rates.

Reducing the volume of wastewater which gets treated at the wastewater treatment plant also reduces the amount of money the City pays to treat it.  A reduction in the annual cost to treat wastewater will allow the City the opportunity to reallocate these funds towards the completion of replacement or rehabilitation of the City’s aging wastewater infrastructure.