Stormwater Management Requirements for Land Development Proposals

Applying MTO Drainage Policy

The fundamental basis of MTO drainage policy is to ensure that water conveyed through highway drainage works will not infringe upon the riparian rights of landowners located upstream or downstream of the highway right-of-way. Accordingly, the proponent must recognise that MTO will not approve a land development proposal if the riparian rights of any landowner may be infringed upon by the proposed land development.

The primary sources for the above noted policy, and other MTO drainage policies are derived from two principle sources:

For specific information on MTO drainage policy, refer to the following sections.

The MTO Regional Highway Planning and Design Office or the local MTO District Office may alter requirements presented in this document, since an extensive SWM report is not always required. MTO may make provisions to accept a drainage impact analysis that has a lower level of detail associated with it, provided that the proponent submits a plan showing how stormwater runoff from the proposed land development will be conveyed to the receiving drainage system. The proponent must be able to demonstrate that drainage impacts to the highway right-of-way or upstream/downstream riparian landowners will not occur, and that the capacity of the highway drainage system will not be exceeded as a result of stormwater runoff discharging from the proposed land development.


Elements of Common Law

Common law is a matter of precedents that are modified by court rulings. Common law governs unless it is superseded by statute law. Common law is founded on the principle, water flows naturally and should be permitted thus to flow, and can be divided into three main categories:

  • natural watercourses;
  • surface or sheet flow; and
  • subsurface flow.

Refer to the "Drainage Management Manual" (MTO 1997), Chapter 2 Appendix 2B, for more details.

Natural Watercourses

A natural watercourse is:

  • formed by the flowing of water that must be present to the eye on casual examination with the unmistakable evidence of the frequent action of running water; or
  • constituted if there is sufficient natural flow of water to form and maintain a distinct and defined channel.

Therefore, a natural watercourse could be in the form of a stream, a ditch, concrete channel or closed conduit.

Aspects of common law that pertain to natural watercourses include the following.

  • Riparian Rights and Obligations: a riparian owner is one whose land is in actual contact with a natural watercourse. Specific riparian rights include:
    • the right to drain that land into the watercourse;
    • where it traverses that land, the right to benefit from the water flowing through the watercourse in its natural state;
    • obligations to receive it even if it becomes a nuisance due to flooding, erosion or other reasons;
    • the owner has no legal ground to complaint if upstream riparian owners reasonably use the watercourse as an outlet, even though the result could be an increase in the amount of water; and
    • persons not riparian owners who obtain an outlet to the stream are liable to a downstream riparian owner whose land is damaged by the increased amount of water.

     
  • Use of Water: a riparian owner has the right to have the water flow in its natural state with regard to both quantity and quality, subject to certain qualifications, and may put the water from the natural watercourse to any reasonable use. Reasonable use of a stream has been defined as a use up to the capacity of the banks of the stream.
     
  • Interference with Natural Watercourses: anyone who interferes with a natural watercourse, must ensure that the works are adequate to carry the flow of water, even that resulting from an extraordinary rainfall.

Surface or Sheet Flow

An owner who paves the surface of their land and thereby increases the rate of surface runoff is not normally liable under common law, even though his/her action may aggravate previously existing flooding problems.

Such lack of liability does not absolve the owner from assessing the environmental implications of increasing the runoff.

If a ditch, pipe or curb and gutter is constructed to collect surface water, it is then necessary to provide a sufficient outlet for the collected water.

An owner does not have the right to collect surface water in this fashion and discharge it onto the lands of other riparian landowners.

Subsurface Flow

Subterranean flowing streams that have definite courses may be treated for all practical purposes, as natural watercourses on the surface.

An owner is entitled to put an underground stream to any reasonable use.

Top of page   Top of page


Common Law and the MTO

MTO, as a landowner, has common law rights that other landowners (i.e. developers) must recognize.

These rights generally apply to the use of highway drainage works to service stormwater runoff from areas external to the highway right-of-way. MTO, as a landowner, must also recognize the rights of other landowners (i.e. upstream/downstream impacts, right to an outlet, etc.). These issues are addressed through PHY Directive B014. For convenience, this section contains excerpts from PHY Directive B014. This section does not replace PHY Directive B014. PHY Directive B014 (PDF - 367 KB) must be referred to when evaluating matters of MTO drainage policy.

Fundamental Purpose of Highway Right-of-way and Drainage System

MTO reserves the right to reject any land development proposal that will conflict with any of these fundamental purposes.

  • Ensuring that existing transportation needs are met, and that future transportation needs are also met. Future transportation needs include constructing new highways; widening existing highways; constructing roadside ancillary facilities and roadway protective works, etc.
  • Water crossings, (i.e. culvert, bridge) of a highway drainage system located on the flow route of a catchment, are there to convey highway stormwater runoff and stormwater runoff from natural drainage tributary areas.
  • Surface drainage systems, which run parallel to the roadway, are design to convey highway stormwater runoff but not to convey collected stormwater runoff discharging from lands that are external to the highway right-of-way, except through riparian right and only in its natural state for both quantity and quality.

Drainage Works by Outside Parties Constructed within the Highway Right-of-way

This section contains excerpts from PHY Directive B014 (PDF - 367 KB) (Policy Area 2: Drainage of Lands Owned by Others) which has been modified to suit the purposes of this document. This section does not replace PHY Directive B014. PHY Directive B014 must be referred to when evaluating matters of MTO drainage policy.

If a proposal is for use of the highway right-of-way for drainage works that will not be shared by the MTO and the highway right-of-way area is no longer needed by the MTO, the highway right-of-way area will be deemed as surplus. Its use and disposal will be dealt with as such. The discussion below does not apply to this case.

If the MTO approves the SWM report, permission for use of the highway drainage system will be granted only to the municipality that has jurisdiction over the land development area. This would make it practical for the MTO to enforce compliance with the conditions of permission, since the municipality is a statutory body rather than a private party. For a territory without municipal organization, refer to PHY Directive B014 (Policy Area 2-5: Drainage of Lands Owned by Others – Territory without Municipal Organization).

Conditions of Permission to Use:

  1. The proponent's drainage works tributary to a highway drainage system or constructed in a highway right-of-way, shall not be deemed to be works constructed under the Public Transportation and Highway Improvement Act. The proponent shall be responsible for obtaining all necessary approvals from the regulatory agencies for their drainage works.
  2. The proponent agrees to put in place necessary erosion and sediment control works for the proposed land development area prior to removal of soil cover, so that sediment does not accumulate in the highway drainage system. The proponent agrees also to bear any costs associated with the clean out of sediment within the provincial highway drainage system resulting from the construction of the proposed land development.
  3. The proponent obtains a resolution from the municipality addressed to the MTO stating that the municipality agrees to assume ownership and operation/maintenance of the proposed drainage works in the land development area, drainage connections to the highway drainage system, and related costs.
  4. The municipality must enter into an understanding with the MTO as described below.
  5. An Encroachment Permit will be required. As conditions of an Encroachment Permit, the municipality agrees to:
    • use the highway drainage system in accordance with the approved SWM report; and
    • fulfil the undertaking of ownership, operation and maintenance of drainage appurtenances no later than the completion of land transactions associated with the land development.
  6. In addition to an Encroachment Permit, an agreement with the municipality will be required (except for works constructed under the Drainage Act), if the proposed drainage works are more than a simple drainage connection. The municipality shall be responsible for all the engineering and construction costs of the proposed works, all future replacement costs, and also any relocation costs as specified in the agreement. When replacement of the drainage works is required, the municipality shall be responsible for all costs and the securing of the necessary approvals prior to re-issuance of an Encroachment Permit for the replacement works.
  7. Due to safety and practical reasons, the MTO will operate and maintain the permitted drainage works located within the highway right-of-way according to MTO standards and practice. The agreement must clearly define the municipality's responsibilities for maintenance, liabilities, relocation of the permitted drainage works whenever required by the MTO, and compliance with requirements of other regulatory agencies.
  8. The construction of drainage works within the highway right-of-way will require conformity to the MTO engineering standards (e.g. “Highway Drainage Design Standards” (MTO 2008), "Drainage Management Manual" (MTO 1997), PHY Directive B-012 "Drainage Act — MTC Policy and Procedures").

For Territories without Municipal Organization

This section contains excerpts from  PHY Directive B014 (Policy Area 2: Drainage of Lands Owned by Others) which has been modified to suit the purposes of this document. This section does not replace PHY Directive B014. PHY Directive B014 must be referred to when evaluating matters of MTO drainage policy.

The MTO may make special provisions to allow relaxation of Policy Area 2-3 for land developments in a territory without municipal organisation. Since land development in a territory without municipal organization is generally minimal, there usually is no need for the development of an extensive stormwater management plan. Where a highway drainage system is proposed for use by a proposed land development in a territory without municipal organization, a basic plan showing how the drainage from the proposed land development will be conveyed should be shown. If permission to use a highway drainage system is given, it should be covered by an Encroachment Permit. Certain conditions requiring municipal ownership may be waived at the discretion of the District Engineer according to local situations.

Consider a Planned Shared Use of the Highway Drainage System

This section contains excerpts from PHY Directive B014 (Policy Area 3: Planned Shared Use of a Drainage System) which has been modified to suit the purposes of this document. This section does not replace PHY Directive B014. PHY Directive B014 must be referred to when evaluating matters of MTO drainage policy.

Planned shared use of drainage systems will generally involve a drainage system of a provincial highway or a municipality. The drainage works may be part of a proposed land development, however, the municipality will more than likely have assumed ownership of such works. Where the planned shared use of a drainage system is proposed between the proponent and the MTO, an MTO drainage representative should be contacted. MTO agreement to share use requires approval of the Regional Director.

The shared use of a proposed drainage system would normally have been identified in a drainage plan endorsed by the MTO (e.g. Subwatershed Plan, Master Drainage Plan). If the MTO accepts the land development proposal after being satisfied that the proposal is in the MTO's best interests, the MTO will enter into an agreement with the municipality for the shared use on the following conditions.

  1. The shared use is for the conveyance of the agreed rate of stormwater discharge only; the responsibility for regulating stormwater runoff from the land development tributary areas remains with the municipality.
  2. When the proposed shared use involves drainage works that are located outside the highway right-of-way, the MTO will offer to enter into an agreement with the municipality for shared use of the drainage works, provided that an appropriate drainage study (e.g. Subwatershed Plan, Master Drainage Plan, SWM report, etc.) of the tributary area has been completed.
  3. The MTO, through the MTO Regional Highway Planning and Design Office will, under the agreement, contribute to the cost of the drainage works in proportion to shared use. The cost includes those of planning, design, construction and, where applicable, land and operation and maintenance costs. The maintenance costs will also include waste management of the materials accumulated in drainage systems including stormwater management detention facilities.

Top of page   Top of page


Statutory Mandates of the Regulatory Agencies

The statutes governing water management are presented below. Refer to the following sections in Chapter 2 of the "Drainage Management Manual" (MTO 1997) for additional information on:

  • Appendix 2C — Statute Law;
  • Appendix 2D — Agency Mandates; and
  • Appendix 2E — Documents Supporting Statutory Mandates.

Federal Statutes

  • The Federal Fisheries Act (DFO).
  • The Canada Water Act (DOE).
  • Navigable Waters Protection Act (TC).
  • Canadian Environmental Assessment Act (DOE).

Provincial Statutes

  • Ontario Water Resources Act (MOE)
  • Environmental Protection Act (MOE)
  • Environmental Assessment Act (MOE)
  • Conservation Authorities Act (MNR)
  • Lakes and Rivers Improvements Act (MNR)
  • Drainage Act (OMAFRA)
  • Planning Act (MMAH)
  • Municipal Act (MMAH)

Top of page   Top of page


Statutory Mandate of MTO

MTO's regulatory water management role is mandated by the Public Transportation and Highway Improvement Act (PTHIA). Water management approvals are issued through Encroachment Permits or Building and Land Use Permits.

The water management mandate of MTO is defined by the following.

  • MTO Drainage Directives.

    Note: Documents are best viewed when printed.


     
  • "Drainage Management Manual" (MTO 1997).
  • “Highway Drainage Design Standards” (MTO 2008).
  • "Drainage Guidelines for Corridor Management" (MTO 1998)*.

MTO, as an agent of the Crown, will not issue an approval that will contravene another regulatory agency's statutory mandate. For this purpose, and prior to issuing any approvals, MTO requires confirmation that the necessary approvals from other regulatory agencies have been granted, approvals in principle have been provided or no approvals are required. MTO permit approval may be given conditional on such an approval being granted.

MTO will interact with other regulatory agencies to confirm their positions and resolve any legislative conflicts if they arise.

Top of page   Top of page


Design Criteria for Highway Drainage Works

Highway drainage system design criteria are outlined in “Highway Drainage Design Standards” (MTO 2008), or the "Drainage Management Manual" (MTO 1997). Refer to these documents for complete details. For convenience, excerpts from these documents (with noted references) have been included in the following sections. Contact the MTO Regional Highway Planning and Design Office for more details.

  • Regulatory storm passageis discussed in “Highway Drainage Design Standards” (MTO 2008). Where a highway drainage works will increase flooding of buildings or developable land during a regulatory flood, it shall be designed to the regional flood criteria, unless otherwise approved. The highway major system will accommodate the regulatory storm flow that exceeds the capacity of the highway storm sewer system.
     
  • Design flow frequency (refer to “Highway Drainage Design Standards”(MTO 2008) for further details):
     
    Road Classification Highway Bridge or Culvert Highway Storm Sewer or Roadside Ditch Highway Major System Stormwater Management Detention Facilities1
    Total Span up to 6.0 m Total Span over 6.0 m

    Freeway Urban Arterial

    50 yr flow

    100 yr flow

    10 yr flow

    100 yr flow

    • post to pre control of selected peak flow frequencies
    • under control of selected peak flow frequencies
    • over control of selected peak flow frequencies

    Rural Arterial Collector Road

    25 yr flow

    50 yr flow

    10 yr flow

    100 yr flow

    Local Road

    10 yr flow

    25 yr flow

    5 yr flow

    100 yr flow

    Depressed Roadways (e.g. subways)

    25 yr flow

    100 yr flow

    Note 1: Level of control must be selected to completely mitigate drainage impacts to the receiving drainage system. Refer to Assessing Impacts to the Receiving Drainage System for more details.

  • Level of Control for Water Qualityis based on the MNR receiver classification: Level 1, Level 2, Level 3, and Level 4 (refer to “Stormwater Management Planning and Design Manual”, MOE 2003); and % removal of sediment is based on a 24 hour detention time.
     
    MNR Classification % Removal *

    Level 1
    Level 2
    Level 3
    Level 4 (for infilling development)

    80
    70
    60
    50

    * based on 24 hour detention time


  • The major system should be checked as it provides a continuous overland route for the portion of the flow that cannot be conveyed by the minor system. Hazards to the travelling public and damage to property adjacent to the highway must be prevented. The highway must also be checked against major flows to ensure that it can remain accessible to emergency vehicles during major storm events unless such access is not required. For further details refer to page 56 in Chapter 3 of the "Drainage Management Manual" (MTO 1997).
  • Flow along highways should be kept within reasonable limits during major storms, to permit the passage of emergency vehicles and for safety considerations. Suggested guidelines are as follows:
    • crown of freeway to remain unsubmerged;
    • depth of flow at crown of arterial road should not exceed 0.15m; and
    • depth of flow at gutters should not exceed 0.4m.
  • Freeboard requirements for highway roadside ditches or stormwater management detention facilities: as a guide use 0.3m.
  • Freeboard requirements for highway bridges and culverts are are discussed in the “Highway Drainage Design Standards” (MTO 2008), which states that the Freeboard shall be greater than or equal to 1.0m for freeways, arterials and collectors, and 0.3m for local roads. These Freeboard requirements also apply to roadways which are parallel to the watercourse under the bridge. Where walkways, bikeways, or maintenance roads are constructed under a bridge, the elevation of the walkway shall be set 0.5 metres above the average summer water level for bridges that have a span up to 6.0 metres, and 1.0 metres for bridges with a span greater than 6.0 metres. For further details refer to WC-2 on page 27 of the “Highway drainage Design Standards” (MTO 2008).
  • Relief flow may be permittedover the highway during regulatory storm events at bridge or culvert crossings to accommodate flood flows (refer to WC-13 “Highway Drainage Design Standards” (MTO 2008). For further details refer to page 28 in Chapter 3 of the "Drainage Management Manual" (MTO 1997).
  • The design flow criteria may be modified in exceptional cases, such as for unusually large structures, unusually low traffic volumes, or for vital routes which must remain useable during regional flood conditions. Use of regional flood criteria in the latter case shall be justified by a cost-benefit analysis.
  • Other design criteria are presented in the "Drainage Management Manual" (MTO 1997).
    • In Chapter 3: pages 39 to 42 (bridges), 44 to 49 (culverts), page 58 (storm sewers), 60 (roadside ditches), 62 (highway major system), and pages 75 to 86 (stormwater management detention facilities).
    • In Chapter 4: ditch cross section and lining (page 12), profile invert and crest elevations (page 12), roadside safety (page 13), porous soil (page 13), limited availability of right-of-way (page 13), aesthetic considerations (page 14), sewer materials (page 39), sewer elevations (page 40), hydraulic conditions in the sewer (page 40), sewer outlet conditions (page 40), exfiltration to the road subgrade (page 41), safety to people and vehicles (page 41), sewer accessories (page 41), curbs and gutters (page 51), gutter inlets (page 52), longitudinal grades (page 52), cross fall (page 52), hydroplaning (page56), median barriers (page 56), shoulder gutters (page 56), external tributary areas (page 56), gutter flow calculation (page 56), inlet spacing (page 57), and stormwater management detention facilities (79 to 82).
    • In Chapter 5: detailed hydraulic design (page 4), flow conveyance and backwater (page 9), scour (page 43), river ice (page 78) and debris flow (page 93).

Top of page   Top of page


The principal concern for MTO is the responsibility for ownership, operation and maintenance of any proposed drainage works. These responsibilities must be designated through an appropriate legal agreement before MTO will issue any final approval. Legal agreements are presented under two cases.

Case 1: Proposed drainage works to be placed within the highway right-of-way.
Case2:Proposed drainage works to be placed outside the highway right-of-way.

Case 1: Proposed Drainage Works to Be Placed Within the Highway Right-of-way

  • The general intent of PHY Directive B014 is to deter drainage or stormwater management works, associated with land development proposals from being placed within the highway right-of-way.
  • Where this cannot be prevented, the Implementation Guidelines for PHY Directive B014 (PDF - 367 KB) presents conditions pertaining to Policy Area 2, Drainage of Lands Owned By Others which must be fulfilled before the MTO will grant permission to use.
  • MTO will grant permission to use only if the municipality enters into a legal agreement with the MTO regarding operation and maintenance of the drainage works.

Form of Legal Agreement

PHY Directive B014 (PDF - 367 KB) Implementation Guidelines requires the following:

  • an Encroachment Permit to be issued to the municipality, complete with Standard Conditions of Approval appended; or
  • for significant works, a separate legal agreement can be secured, complete with Standard Conditions of Approval.

Standard Conditions of Approval

  1. The municipality will be liable for any maintenance costs that are incurred as a result of damages caused to the highway right-of-way, where the damage can be attributed to the drainage works associated with the proposed land development.
  2. Where a specific drainage works (e.g. stormwater management detention facility, storm sewer restrictor) is located within the proposed land development, the drainage works are to:
    • remain in place;
    • be a requirement that is binding on all future heirs and successors of the land development; and
    • be a requirement that is enforceable through the courts.

  3. Responsibility for the municipality must be clearly defined for the proposed drainage works that will be located within the highway right-of-way, including:
    • all engineering and construction costs;
    • all future replacement costs and any specified relocation costs; and
    • maintenance and liability costs, whenever specified by the MTO.
  4. For safety reasons, MTO will operate and maintain the permitted drainage works located within the highway right-of-way, according to MTO drainage practice.
  5. The proponent shall be responsible for obtaining all necessary approvals from the regulatory agencies for the drainage works associated with the proposed land development.
  6. The proponent agrees to put in place necessary erosion and sediment control works for the proposed land development area prior to removal of soil cover, so that sediment does not accumulate in the highway drainage system. The proponent agrees also to bear any costs associated with the clean out of sediment within the highway drainage system resulting from the construction of the proposed land development.
  7. The construction of drainage works within the highway right-of-way will require conformity to MTO drainage practice.

Case 2: Proposed Drainage Works to Be Placed Outside the Highway Right-of-way

  • A legal agreement is not always required. However, in meeting the general requirements of PHY Directive B014, it is good practice to consider some form of a legally binding agreement that will absolve the MTO from future operation and maintenance liabilities
  • MTO may enter into a legal agreement regarding operation, and maintenance of the drainage works with the owner.
  • The owner may be the municipality; however ownership depends on the type of drainage works and the form of the proposed land development.
    1. For Site Plans, municipal ownership of the drainage works should not be considered because:
      • the proposed land development is contained in a single block;
      • the drainage works (e.g. stormwater management control) cannot be delineated by a property boundary;
      • under Site Plan control drainage works are generally privately owned; and
      • the Site Plan process does not contain mechanisms that facilitate transfer of land (e.g. the land housing a stormwater management control).
    2. For Draft Plans of subdivisions, municipal ownership of the drainage works can be considered because:
      • the proposed land development is subdivided into different blocks;
      • the drainage works (e.g. stormwater management control) can be delineated by a property boundary;
      • under Draft Plan control drainage infrastructure is generally transferred to municipality;
      • the Draft Plan can be modified to include a block which contains the drainage works (e.g. stormwater management control) ; and
      • the block(s) housing the drainage works can be registered, on title, to the municipality.

Form of Agreement

Any form, provided that the agreement includes Standard Conditions of Approval i to iv .

Standard Conditions of Approval

  1. The owner will be liable for any maintenance costs that are incurred as a result of damages caused to the highway right-of-way, where the damage can be attributed to the drainage works associated with the proposed land development.
  2. Where a specific drainage works (e.g. stormwater management detention facility, storm sewer restrictor) is located within the proposed land development, the drainage works are to:
    • remain in place;
    • be a requirement that is binding on all future heirs and successors of the land development; and
    • be a requirement that is enforceable through the courts.
  3. The proponent shall be responsible for obtaining all necessary approvals from the regulatory agencies for the drainage works associated with the proposed land development.
  4. The proponent agrees to put in place necessary erosion and sediment control works for the proposed development area prior to removal of soil cover, so that sediment does not accumulate in the highway drainage system. The proponent agrees also to bear any costs associated with the clean out of sediment within the highway drainage system resulting from the construction of the proposed land development.

For Territories without Municipal Organization

Conditions regarding municipal ownership may be waived at the discretion of the District Engineer according to local situations.

Top of page   Top of page

Back to Top