Stormwater Management Requirements for Land Development Proposals

Identifying Drainage Issues

Having determined that a SWM report is required by MTO, the proponent should review all of the following drainage issues related to the proposed land development.



Outlining the Status of the Land Development Proposal

A proposed land development requires approvals from the municipality and regulatory agencies. The SWM report should outline the status of the land development proposal by providing documentation on the following areas.

Preliminary or Detail SWM Report

At the preliminary stage the SWM report will typically outline all potential impacts that are caused by the proposed land development, recommend mitigative works, and demonstrate the feasibility of the mitigative works.

At the detailed stage, the SWM report will typically provide the detailed design and demonstrate adherence with all requirements that have been set.

Documentation Required in SWM Report

Clarify whether the report is preliminary or detailed in nature.

Relevance to MTO

  • The types of comments provided by MTO will depend on whether the report is preliminary or detailed.
  • MTO review of the SWM report at the preliminary stage is to set requirements for approval.
  • MTO review of the SWM report at the detailed stage is to issue final approval.

Land Use Designations

The local municipality typically plans and regulates the development of private land by approving areas for development and designating the type of land development (e.g. residential, commercial, industrial) that is permitted. Land use planning designations are documented in municipal planning documents such as:

  • Official Plans;
  • Official Plan Amendments;
  • Secondary Plans;
  • Secondary Plan Amendments; and
  • Zoning By-laws.

Land development proposals must be in conformance with municipal planning documents.

Documentation Required in SWM Report

The SWM report should clearly indicate all land use designations, particularly those associated with land drainage (i.e. hazard land or flood plain designations). Conformance with the hazard land or flood plain designations must be clearly documented in the report. If changes to these designations are required to accommodate the proposed land development, the report should provide information regarding the required zoning changes. Any unresolved issues associated with the proposed changes should be highlighted complete with the steps that are being taken to resolve them.

Relevance to MTO

  • It may be too soon in the municipal approval process for MTO to conduct a review of the SWM report, if the land use designation has not been approved (i.e. by the municipality). Contact the local MTO District Office or MTO Regional Highway Planning and Design Office for clarification.
  • As an agent of the crown, MTO will not approve a SWM report that will contravene the mandate or authority of another regulatory agency.

Conditions of Approval (Draft Plan of Subdivision or Site Plan)

During the circulation process, regulatory agencies, including MTO, may request Conditions of Approval. These conditions could include the requirements for submitting a SWM report.

As the preliminary and detail designs are submitted to the various regulatory agencies, the conditions will have to be cleared. Any drainage conditions set by MTO would be reviewed and clearance will be contingent on satisfying the requirements of MTO, as outlined in this guide.

The MTO may place a reqirement for a Storm Water Management report on a Site Plan or Draft Plan of Subdivision to address issues related to:

  • on site stormwater management detention facilities;
  • temporary sediment and erosion control during construction;
  • provisions for a suitable outlet;
  • limits related to design flow capacity associated with a highway water crossing or the highway surface drainage system, and/or
  • Ownership of SWM facilities.

Documentation Required in SWM Report

The report must clearly indicate the drainage related requirements imposed by MTO and document how they are satisfied by the proposed submission.

The report should also provide all other Conditions of Approval that pertain to land drainage, which regulatory agency is responsible for clearing the condition, and the status of the clearance with that agency.

Relevance to MTO

  • To provide clearance of a Condition of Approval, MTO must ensure that all Conditions of Approval imposed by MTO are addressed satisfactorily.
  • In some cases, MTO may circulate a land development proposal that is beyond the jurisdictional control of the Public Transportation and Highway Improvement Act, and will not require a permit from MTO (e.g. Encroachment Permit, Building and Land Use Permit) to be issued for the proposed land development. In such cases MTO will address any highway drainage concerns by requesting suitable Conditions of Approval during the circulation process.
  • As an agent of the crown MTO will not clear any Condition of Approval until those of all regulatory agencies have been cleared; or an approval in principle is provided. Confirmation of final approval should be forwarded to MTO.
  • MTO can issue an approval in principle for the SWM report if it is required by the proponent to secure clearances from other regulatory agencies.
  • Conditions imposed by other regulatory agencies should not compromise the highway drainage system.
  • Should a Condition of Approval of another regulatory agency conflict with those of MTO, or vice versa, a meeting between the parties may be warranted to resolve the conflict.

Regulatory Approval Process

In addition to the local municipality, the MNR, MOE, and the local conservation authority (where applicable) may also review the SWM report. In some cases the Department of Fisheries and Oceans may also be involved. Refer to Statutory Mandate of the Regulatory Agencies for a summary of regulatory agency mandates.

Documentation Required in SWM Report

The report should indicate all the regulatory agencies involved in the review of the land development proposal and provide an update on the status of approvals with each of the agencies. Copies of documentation (i.e. letters of approval, permits, etc.) from the various regulatory agencies involved should be appended to the proposal as they become available.

Relevance to MTO

  • As an agent of the crown, MTO will not provide an approval that will contravene the mandate or authority of another regulatory agency. As a result, MTO requires the SWM report to be approved by all regulatory agencies; or an approval in principle is provided by the regulatory agency. Confirmation of final approval should be forwarded to MTO.
  • MTO will review the requirements set by the regulatory agencies to ensure that MTO requirements will not conflict with those of another agency, and vice versa.
  • Should the requirements of other regulatory agencies conflict with MTO requirements, or vice versa, a meeting may be warranted to resolve the controversial aspects of the SWM report.
  • MTO can issue an approval in principle for the SWM report if it is required by the proponent to secure clearances from other regulatory agencies.

MTO Permits

As part of MTO's mandate under the Public Transportation and Highway Improvement, certain land development proposals will require that an Encroachment Permit, Building and Land Use Permit, entrance permits, or Signage Permit be obtained from the MTO.

Issuance of these permits will depend on the jurisdictional requirements (i.e. setback distance between the proposed land development and the highway right-of-way) for each type of permit. Contact the local MTO District Office for further clarification.

Documentation Required in SWM Report

The report should indicate which permits are required from MTO.

A background check on the site, with the assistance of the local MTO District Office, would turn up any previous permits that may have been issued in the past for the proposed land development. Clarification on the validity of the previous permit, and any changes to the MTO drainage practice that might affect the required permit can also be obtained. All relevant issues should then be summarised in the SWM report (e.g. partial construction of the proposed land development, validity of permit, expiry dates, conditions of approval of the permit, applicability of the previous conditions on current land development proposals, and ownership of the property, etc.).

Relevance to MTO

  • Where MTO has issued a permit, the status and applicability of that permit for the proponent or the proposed land development must be determined.
  • Should approvals of other regulatory agencies conflict with MTO requirements, or vice versa, a meeting may be warranted to resolve the controversial aspects of the SWM report.
  • MTO can issue an approval in principle if it is required by the proponent to secure clearances from other regulatory agencies.

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Reviewing Previous Drainage Studies

The SWM report should document any previously completed drainage studies that are to be used for the proposed land development by providing documentation on the following areas.

Previous Drainage Studies

Previous drainage studies include the following.

  • Watershed, subwatershed and master drainage plans provide the goals, objectives and criteria for the management of resources in a watershed, subwatershed or area of specific interest.
  • Preliminary SWM reports are typically submitted at the earlier stage of design to outline all potential impacts that are caused by the proposed land development, recommend mitigative works, and demonstrate the feasibility of the mitigative works.
  • Detailed SWM reports are typically submitted at the detailed design stage to provide the detailed design and demonstrate adherence with all requirements that have been set.
  • Other types of drainage studies could include (sources include conservation authorities, MNR, MOE, and municipalities):
    • Flood Damage Reduction Program Studies (FDRP studies);
    • erosion control studies;
    • flood control studies; or
    • combinations of the above.

Documentation required in SWM Report

Where a previous drainage study is in existence and any objectives, goals, design criteria and other elements from that study are intended to be used in the proposed SWM report, the report must clearly indicate if MTO formally endorsed the previous drainage study.

  • If MTO endorsed the previous drainage study documentation of relevant objectives, goals, design criteria and other elements of the referenced study must be included (with clear references to its source). This may include:
    • limits on regulatory flood flows and water levels;
    • water quality objectives;
    • fish habitat restoration or protection objectives;
    • identification of flood or erosion prone areas;
    • the type of drainage system that is required; or
    • requirements for stormwater management controls.

    Adherence of the SWM report to the referenced drainage study must also be clearly documented. When making submissions based on previously completed drainage studies, changes that have occurred to MTO drainage practice must be considered (i.e. MTO continually updates its drainage practice). Other agencies also undertake these types of updates. Contact the MTO Regional Highway Planning and Design Office to determine if changes have occurred to the MTO drainage practice since the previous drainage study was completed. If there has been changes, the proponent must demonstrate how the previously completed drainage study is in conformance with current MTO drainage practice.

  • If MTO did not endorse the previous drainage study, there may be two reasons. The SWM report should document which of the following reasons apply.
    1. MTO may not have endorsed the previous drainage study since MTO was not on the circulation list and had not reviewed it. In this case, the previous drainage study should be reviewed by MTO for conformity to MTO drainage practice. Should the study be acceptable to MTO, an endorsement can be issued. Once complete, the proposed SWM report can be reviewed on the basis of conformity to the previous drainage study.
    2. MTO may not have endorsed the previous drainage study because of a disagreement with certain objectives, goals, design criteria or other elements of the previous drainage study. Determine the aspects of the previously completed drainage study that were not acceptable to MTO. Once this has been established there are two options available.
      • If the proposed SWM report does not encompass any area of disagreement, MTO can review the SWM report in isolation of the previously completed drainage study. The review would be based on conformity with current MTO drainage practice.
      • If the proposed SWM report encompasses an area of disagreement, a meeting between all supporting regulatory agencies is warranted to sort out those controversial aspects of the previously completed drainage study. During this activity, MTO is not in a position to review the proposed SWM report and would be unable to approve the SWM report, issue any permits for the proposed land development, or clear any Conditions of Approval.

Relevance to MTO

  • Any previous drainage study that was endorsed by MTO must be referenced in the SWM report
  • The SWM report must show conformance with the previous drainage study if it was endorsed by MTO.
  • The review of the SWM report may be accelerated if MTO endorsed a previous drainage study.
  • The review of the SWM report can be delayed if a previous drainage study, not endorsed by MTO, will be referenced. Any disputes should be identified before first submission.

Previous Environmental Study Reports, Preliminary Design Reports and Detail Design Reports for Provincial Highways

When proposing to discharge stormwater runoff from a proposed land development into the highway right of way, either in the highway surface drainage system or into a highway water crossing, it may be necessary to obtain design information regarding the highway drainage works. To obtain this information or data, it is prudent to consult with the MTO Regional Highway Planning and Design Office. Information may be available from environmental study reports, preliminary design reports and detail design reports. This information should be used to check the capacity of the existing highway drainage system.

Documentation Required in SWM Report

The SWM report should provide documentation on the relevant objectives, goals, design criteria and other elements of the previous highway design report (with clear references to its source), such as:

  • limits on regulatory flood flows and water levels;
  • water quality objectives;
  • fish habitat restoration or protection objectives;
  • identification of flood or erosion prone areas;
  • drainage system requirements; or
  • requirements for stormwater management controls.

Relevance to MTO

  • Existing or future highway needs should not be compromised by the proposed land development.

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Establishing the Need for Water Quality Treatment

Generally, in land development proposals, the MOE will determine the need for stormwater management quality control. The document titled (“Stormwater Management Planning and Design Manual” (MOE 2003), provides general guidance on the planning and design of stormwater quality control facilities.

The need for stormwater management quality control is based on the sensitivity of the receiving draingae system, and may be a requirement placed on the proposed land development by the regulatory agencies before any impact assessment has been completed.

Documentation Required in SWM Report

Document the requirements, if any, for water quality that has been placed on the proposed land development by the regulatory agencies.

Relevance to MTO

  • As an agent of the crown MTO will not provide an approval that will contravene the mandate or authority of another regulatory agency.
  • MTO reserves the right to input into water quality requirements imposed upon the land development proposal, when drainage from a land development will be entering the highway surface drainage system and will be conveyed to a receiving drainage system. Requirements set by the regulatory agencies should not conflict with the requirements of MTO, and vice versa.
  • The primary concern for MTO is with regards to the riparian rights of upstream or downstream landowners. If the MTO could become unduly exposed to legal action, MTO reserves the right to impose or increase, whichever is applicable, the requirements imposed upon the land development proposal. An MTO drainage representative should be contacted for clarification.
  • Should the requirements of other regulatory agencies conflict with MTO requirements, or vice versa, a meeting may be warranted to resolve the controversial aspects of the SWM report. For stormwater management quality control requirements refer to, Providing Stormwater Management Controls.

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Identifying Fish Habitat Requirements

Generally, in land development proposals, the MNR, DFO, or the local conservation authority will determine fish habitat requirements. Since fish habitat requirements are based on the sensitivity of the receiving drainage system, requirements may be set before any impact assessment has been completed.

Documentation Required in SWM Report

Document the requirements, if any, for fish habitat mitigation that have been placed on the proposed land development by the regulatory agencies. Clarify that the proposed method of mitigation will not impact the highway drainage system. Refer to the appropriate section listed below for more detail.

Relevance to MTO

  • As an agent of the crown MTO will not provide an approval that will contravene the mandate or authority of another regulatory agency.
  • MTO reserves the right to input into fish habitat mitigation requirements imposed upon the land development proposal when the proposed method of mitigation may cause an impact to the highway water crossing. Requirements set by the regulatory agencies should not conflict with the requirements of MTO, and vice versa. Contact the MTO Regional Environmental Section for further guidance.
  • Where any proposed method of fish habitat mitigation is to be placed within the highway right-of way, refer to the following sections. Contact the MTO Regional Environmental Section for further guidance.
  • Should the requirements of other regulatory agencies conflict with MTO requirements, or vice versa, a meeting may be warranted to resolve the controversial aspects of the SWM report.

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