Stormwater Management Requirements for Land Development Proposals

MTO SWM Requirements Checklist

The checklists presented below provide a comprehensive list of potential documentation requirements to be included in a SWM report submitted to MTO. It is the responsibility of the drainage practitioner to determine the applicability of the potential documentation requirements. Selection should be based on the suitability to each particular land development proposal, and will depend on the scale and nature of the proposed land development.

These checklists should be used to check that:

  • the various tasks presented in the subsequent sections of this document (refer to Figure 1: Organization and Sequence of Tasks), have been recognised in the SWM report;
  • the documentation in the SWM report is adequate; and
  • all drainage issues and impacts have been identified and mitigated to the satisfaction of MTO.

Checklist 1: Background Information Required to Identify Drainage Issues

Download Checklist 1 for printing (PDF - 44 KB)

Category Items or Elements Discussed in SWM Report Applicable Documented
Status of Land Development Proposal Preliminary Stormwater Management Report?
Detail Stormwater Management Report?
Zoning Status of Land Development Proposal:
  • Current Designation
  • Amendments
Existence of MTO Conditions of Approval on:
  • Draft Plan of Subdivision
  • Site Plan
Status of Regulatory Agencies Approvals/Permits
  • MNR
  • MOE
  • Conservation Authority
  • Municipality
  • Others _____________________________
Referenced Drainage Studies Watershed, subwatershed or master drainage studies
Approved SWM reports for same site
Approved detailed SWM reports for same site
MTO environmental study reports
MTO preliminary design reports
MTO detail design reports
Other drainage studies
  • Flood Damage Reduction Program Study (FDRP)
  • Erosion Control Study
  • Flood Control Study
  • Others ___________________________
Water Quality Treatment Requirements:
  • MOE
  • MNR
  • MTO
  • Others ______________________________
Fish Habitat Requirements:
  • MOE
  • MNR
  • MTO
  • Others ______________________________

Checklist 2: Receiving Drainage System Information

Download Checklist 2 for printing (PDF - 133 KB)

Category Items or Elements Discussed in SWM Report Applicable Documented
Receiving Drainage System Information Components (other than highway drainage system):
  • stream channel
  • storm sewers
  • roadside ditches
  • bridges, culverts
  • stormwater management facilities
  • other ______________________________
Operation and Maintenance Responsibilities for Components (other than highway drainage system)
  • agency
  • organisation
  • person
  • other ______________________________
Highway Drainage System
  • bridge
  • culvert
  • storm sewer
  • roadside ditch
  • major system
  • stormwater management facility
  • other _______________________________
Right to Outlet
  • alternative outlets
  • into highway drainage system
  • into receiving drainage system upstream of highway
  • into receiving drainage system downstream of highway
Future Highway Works
  • new highway, expansions, rehabilitation
  • maintenance works
  • drainage works
  • identified conflicts with outlet from the proposed development
Criteria Regulating Receiving Drainage System
  • highway design criteria
  • policy of regulatory agencies
  • MTO policy
  • manuals and guidelines
  • conflicts between MTO and Regulatory Agencies
Known Drainage Problem
  • Upstream or Downstream Riparian Property
  • Lack of sufficient drainage outlet
  • Highway Right-of-way
  • flooding or overtopping of highway bridge or culvert
  • erosion on highway right-of-way
  • erosion at highway bridge or culvert
  • silt in culvert
  • flooding of riparian property
  • erosion on riparian property
  • water quality

Checklist 3: Assessing Impacts to the Receiving Drainage System

Download Checklist 3 for printing (PDF - 47 KB)

Category Items or Elements Discussed in SWM Report Applicable Documented
Reference Points Upstream of proposed land development
Downstream of proposed land development
Upstream of highway drainage system
Downstream of highway drainage system
Along highway drainage system
Control point
Known drainage problems
Parameters to be Calculated Peak Flows
Water surface elevations
Flow Velocities
Runoff Volume
Calculations Range of Frequencies to be Analyzed
  • low flow events (water quality or fisheries)
  • 2 year
  • 5 year
  • 10 year
  • 25 year
  • 50 year
  • 100 year
  • regulatory storm
Design Storm Events
  • type and duration
  • rainfall records and station
  • rainfall discretization
  • input parameters
Watershed/ Catchment area Data
  • discretization and areas
  • land use, soil types, vegetation cover slope and infiltration parameters (CN)
  • pervious and impervious areas, directly connected areas
  • travel length, slope and time to peak or time of concentration
  • recession constants
  • computational time step
  • rational method runoff coefficient
Capacity of Highway Drainage System Bridges and culverts
Storm sewer, roadside ditches and major system
  • design flow frequency
  • freeboard requirements
  • allowable depth of flow on highway surface
  • regulatory storm
Stormwater Management Detention Facilities
Computational Methods
  • culvert analysis
  • bridge analysis
  • flow in open channels
  • assessing channel erosion (including roadside ditches)
  • flow in storm sewers
  • roadway surface flooding
  • flow in stormwater management detention facilities
  • scour potential
  • computer models
Documentation of Impacts Post-development to Pre-Development Scenario Comparison
  • suitability of reference points
  • peak flow rates
  • water surface elevations
  • flow velocities
  • runoff volumes
  • increased peak flows at references points
  • increased water surface elevations at reference points
  • increased flow velocities at reference points
  • capacity of highway drainage system
Recommendation for Mitigative Works
  • Level of mitigation required at references points
  • level of peak flow reduction
  • level of water surface elevation reduction
  • level of erosion protection required (due to flow velocities)
Mitigative Works Proposed Stormwater Management Controls
  • water quality and/or water quantity facilities
  • type
  • size
  • location (setback from highway)
  • roof top or parking lot controls
  • device used
  • location and layout
  • volume controlled
  • operation and maintenance responsibilities
Modifications to the Receiving Drainage System
  • modifications to highway drainage works
  • modification to other components of receiving drainage system
  • erosion protection
Results of Modifications
  • peak flows at references points restored
  • water surface elevations at reference points restored
  • level of erosion protection/ flow velocities at reference points
  • capacity of highway drainage system

Checklist 4: Construction Operation and Maintenance Issues

Download Checklist 4 for printing (PDF - 19 KB)

Category Items or Elements Discussed in SWM Report Applicable Documented
Interim and Final Drainage Systems Drainage Plan
  • interim drainage system layout, components and timeframe of use
  • final drainage system layout and components
Erosion and Sediment Control Plan During Construction
  • temporary erosion control works, layout, location and timeframe of use
  • maintenance scheduling of temporary erosion control works
  • maintenance schedule of permanent erosion works
  • maintenance on highway drainage system during construction
Ownership, Operational and Maintenance Responsibilities
  • Legal Agreements
  • Party Responsibilities for:
  • owner of site drainage system
  • maintenance of site drainage system
  • maintenance of permanent erosion control works
  • maintenance on highway drainage system after construction
  • MTO maintenance responsibilities

Checklist 5: Supplemental Drainage Information

Download Checklist 5 for printing (PDF - 12 KB)

Category Items or Elements Discussed in SWM Report Applicable Documented
Rationale and Justification Documentation to Support Selection of:
  • level of detail used in analysis
  • hydrologic and hydraulic computer models
  • selection of computational methods
Figures, Maps and Plans Documentation
  • location/site map
  • land use map
  • soils map
  • natural resources map
  • proposed land development and grading plan
  • drainage plans
  • catchment discretization schematic
  • drainage system connectivity flowchart
  • stormwater management plan
  • In-stream works plan
  • temporary sediment and erosion control
  • location of stream cross-sections
tables and Graphs Input and Output Parameters
  • soil types and CN numbers
  • stormwater management works
  • design storm events
  • hydrologic computational parameters
  • stage-storage-discharge curves
  • hydrologic analysis results
  • hydraulic computation
  • water surface elevations
  • flow velocities
Letters, Permits and Supporting Computer Files SWM report prepared and signed by a Professional Engineer
Copies of correspondence
  • letters of approval
  • copies of permits
  • municipality acceptance of ownership of site drainage system
  • other
Hydrologic modelling input and output
  • disk copy; or
  • computer printout
Hydraulic modelling input and output
  • disk copy; or
  • computer printout

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