On behalf of the Town of…

On behalf of the Town of LaSalle and Town of Kingsville located in the Windsor-Essex Region of Southwestern Ontario, the following comments have been developed upon review of the "Proposed Changes to Environmental Approvals: Linear Infrastructure Approach – ECA Changes for Stormwater Management and Conveyance". The comments below are based on a review of specifically Appendix A - Stormwater Management Criteria.

The Southwestern region of Ontario is known for its flat terrain and existing low soil infiltration capacity. As a result, it has historically been very difficult to account for infiltration within a stormwater design strategy for new developments and retrofits. Receiving watercourses are traditionally sized for a 1:2 year runoff rate based on an existing agricultural land condition, which makes water balance for a site incredibly challenging, as most development sites are required to traditionally overcontrol runoff into the outlet. Meeting water balance for a site in the southwestern Ontario Windsor-Essex region has been proven to be very difficult to achieve and would heavily rely on water reuse for water balance levels during a larger storm event.

The recently released "Windsor/Essex Region Stormwater Management Standards Manual (December 2018)" detailed a thorough review of the Draft MECP LID Stormwater Management Guidance Manual and took into consideration the recommended approaches to incorporate LID in local designs. The document discussed the use of a Runoff Volume Control Target of 32mm for the region which has historically been identified to prove challenging due to underlying soil conditions and low infiltration capacity within the region. In regards to the implementation of lot-level controls through the use of LIDs throughout Windsor/Essex, there is concern by all municipalities as well as the local Conservation Authority (Essex Region Conservation Authority) that the shift to LIDs may prove impractical as a uniformly mandated approach to stormwater management, given the predominance of clay soils, lack of topographic relief, high groundwater in areas and more importantly surface backwater conditions. The region acknowledges the benefits of LID measures for peak attenuation, water quality and volume reduction, but in most instances, there is no significant benefit locally and has potential disadvantages to achieving the goal of maintaining the pre-develoment water balance. With infiltration practices not able to be relied upon, rain harvesting and reuse would be necessary. This is difficult to be monitored by a municipality and/or designer, as they cannot be assured that the homeowner/developer will empty the collected rainfall before the next storm. At this time, municipalities and the local Conservation Authority currently require redundancy which leaves the region to implement traditional on-site retention at a premium.

Additional disadvantages to LID's in the Windsor/Essex region to achieve the required Linear ECA Water Balance include:
- More infiltration could direct water into sewer trenches, thus increasing existing basement flooding risk.
- LIDs require additional pre-treatment to capture oils, debris and suspended solids.
- Inspection and Maintenance over numerous "small scattered" facilities could easily overwhelm local government staff with increasing budgetary constraints and challenges to meet O&M demands.
- LID controls that require pre-treatment can be challenging within road right-of-ways and space can also be limited to avoid existing and future utilities.

The new ECA Stormwater Management Criteria overall appears to fall short of advancing the suggested outcomes highlighted. For example, proposed requirements have the potential to adversely affect municipalities throughout the region through:

Increased regulatory burden and cost by:
- Imposing new development water quality standards to linear infrastructure retrofits (Appendix A - Stormwater Management Criteria, Table 1. Performance Criteria “Works are designed as part of a treatment train in a multi-year retrofit undertaking, in accordance with a rehabilitation study or similar area-wide stormwater study, such that the completed treatment train will achieve the ‘Development’ criteria for Suspended Solids, within 10 years.”);

- Requiring access, operation and maintenance of private works where on-site works are used in a treatment train approach (Schedule D, Clause 5.2/5.2.6 a), “When it is necessary to use privately owned stormwater works in the stormwater treatment train to achieve Appendix A criteria as per condition 5.2.1.d, the following conditions apply: a) The Owner, through legal instruments such as the Drainage Act, has the right to access, operate and maintain the private stormwater works”);

- Requiring a monitoring plan including broad assessment of hydrological, chemical, physical and biological parameters and impacts (Schedule E, Clause 5 “The Monitoring Plan shall be designed to: 5.4.1 Verify that the operational performance of the Municipal Stormwater Management System is as designed/planned”; Clause 5.5.6 c), “Development of a monitoring program for the Works and the receivers identified in conditions 5.5.1 and 5.5.2, that includes: c) Hydrological, chemical, physical and biological parameters, as appropriate, in alignment with the goals identified in 5.5.6 b)”);

- Duplicating reporting on threats and mitigation measures included in existing Clean Water Act reporting (Schedule E, Section 8).

Overdesign of low-risk works that do not recognize:
- “Clear, transparent and consistent design criteria that municipalities and developers can follow for future sewage work” per Appendix A can inadvertently create a generic ‘one-size-fits-all’ approach that does not consider project-specific problems and opportunities, project-specific environmental and community issues, and project-specific solutions;

- “Local site study” and “rehabilitation study” per Appendix A to set appropriate site-level criteria and approaches for water balance and water quality are not practical for small sites, retrofit sites and most development sites within the region where in-situ infiltration rates are low due to the underlying clay soils;

Risks to infrastructure and property:
- Partially-separated area increased private property flood risk liabilities, impacts to pumping and treatment cost, increased risks of structural collapse of sewer and ground systems due to infiltration and the loss of pipe and/or pavement support are not fully recognized as constraints (Appendix A - Stormwater Management Criteria, Table 2. Stormwater Management Practices Site Constraints) and instead must be accepted and “mitigated through design”.

To address these issues identified above and advance the intended outcomes, it is recommended that local pilot studies be required prior to any mandate for regional requirements to the new MECP Linear ECA Stormwater Management Criteria. This would be helpful to i) explore the practicality/feasibility of legal instruments to manage private works, ii) defer the requirement for a monitoring plan, and pilot the development of typical/template plans in order to support municipalities in this broad, new activity, and iii) demonstrate “local site study” and “rehabilitation study” approaches to set site-level criteria for water balance and water quality for small sites or retrofit sites, to avoid potential overdesign.

The current Draft LID Manual is assumed at this time to be read in conjunction with the Linear ECA Stormwater Management Criteria. This Manual addresses cost but does not recognize it as a potential impact. The regional municipalities kindly request that the document state that the expected constraint of project costs have not been considered in the Manual, and should be addressed by a qualified professional considering asset management principles, full lifecycle costs and system-wide impacts.

The Linear ECA Stormwater Management design criteria is also recommended to properly recognize the adverse impacts of infiltration LID measures in flood risk-prone areas.