Stormwater Management Plan by Expert Engineers
(Engineers Specializing in Stormwater Management / Municipal Engineering)

Stormwater Management Report is required to identify the quality and quantity impacts of the change in stormwater runoff on existing
infrastructure and watercourses due to a proposed development. Stormwater Management Report determines improvements to municipal
servicing infrastructure required to support the proposed level of development, Where applicable Stormwater Management Report also
determines mitigation measures to minimize any negative impacts on the drainage system. Stormwater Management Report will also
identify opportunities for enhancement of stormwater management facilities and features in redevelopment sites.
Stormwater Management Reports are prepared by our expert Professional Engineers well experienced in municipal engineering and
stormwater management, and include all appropriate reports, plans, computer modeling results and design calculations relating to how
stormwater run-off is to be managed. The objective of a Stormwater Management Report is to evaluate the effects of a proposed
development on the stormwater and drainage system, and to recommend how to manage rainwater/snowmelt for the proposed
development, consistent with the Wet Weather Flow Management Policy and while also meeting regional conservation authority, provincial
and federal regulations.

Our Expert Professional Stormwater Management Engineers prepare and submit Site Plan, Site Servicing, Erosion Control & Grading
Plan and Stormwater Management Report to Obtain Site Plan Approval and Municipal Building Permits from City, Town, Township, County,
Region,  and/or Regional Conservation Authorities like, LSRCA -Lake Simcoe Regional Conservation Authority, TRCA - Toronto Regional
Conservation Authority for Proposed Development, Construction, Renovation or Addition of Commercial, Industrial and Residential
Buildings including Retail Shopping Plazas, Office Buildings, Medical Buildings, Restaurants, Banquet Halls, Gas Stations, Retirement
Homes, Multiplex Residential Units and Custom Build Homes in Ontario including Northern Ontario

Having vast experience in unique distinctive stormwater management, our expert stormwater management engineers offer
effective, innovative and cost efficient concept stormwater management reports, designs, and construction drawings to our
clients. Our well experienced expert professional stormwater management engineers' proficiency in conceptualizing
stormwater management designs and plan in accordance with our clients' requirements has made us very successful.

If the property is covered by a site plan control by-law, building permit will not be issued until the stormwater management  
have been approved by the municipality. In addition to the planning approvals and building permit which are required for a
building project, other permits and approvals including Conservation Authority and Ministry of Transportation approvals.

Our stormwater management engineers prepare thorough, detailed, and clear stormwater management reports to suit your
needs while also adhering to design requirements of the municipality and submit to Municipality  for review and approval to
obtain site plan approval and building permits.

Professional and prompt services of our well experienced expert Professional Municipal Engineers specializing in Stormwater
Management at very competitive cost are always an added value to our customer’s projects. Our expert stormwater management
specialists accomplish of all their commitments through highest degree of integrity & professionalism, objective oriented approach and
continuously upgraded skills & techniques to achieve excellence in their work.

All of our engineers are operating under a Certificate of Authorization issued by the Professional Engineers of Ontario. All design drawings
and reports for Grading, Erosion Control, Site Servicing and Storm Water Management will be endorsed by a Professional Civil Engineer,
specializing in Municipal/Hydrology. Any geotechnical analysis will be endorsed by a Professional Engineer, specializing in hydrogeological
studies. All drawings and reports prepared by the professional engineer will be sealed, signed & dated.

As the grading and storm water management designs are inter-related it is recommended that the engineer and/or engineering
firm that designed the site grading also develop the storm water management scheme.

It is very important that the engineer responsible for storm water management coordinate all related drawings, details and specifications
through the prime consultant to ensure they are compatible with the approved site plan, architectural plans, and landscaping plans, etc.
Drawings that are not compatible with the other disciplines may result in undue delays.

Stormwater Management Report
Stormwater Management is a necessary component of urban municipal infrastructure. Stormwater Management Report evaluates the
effects on the stormwater and drainage system,and to recommend how to manage rainwater and snowmelt, consistent with the Municipal
Wet Weather Flow Management Policy and while also meeting regional, provincial and federal regulations. The required stormwater
management report for any Building Permit application will vary depending on the specific and type of proposed construction for the project.
The level of detail for the Stormwater Management Report depends on the type and scope of application, the size of the development and
the types of stormwater management schemes proposed. For example, a Stormwater Management Report for a Plan of Subdivision will
typically be more complex than a Stormwater Management Report in support of a Site Plan Control application. A Stormwater Management
Report is typically required for the following application types:
  •    Zoning By-law Applications
  •    Plans of Subdivision
  •    Plans of Condominium
  •    Consent to Sever
  •    Site Plan Control applications
Under natural conditions, stormwater (rainwater and melted snow that flows over roads, parking lots, lawn and other sites) is intercepted by
vegetation and then absorbed into the ground and filtered and eventually replenishes aquifers or flows into streams and rivers. Later, part of
it is returned to the atmosphere in the form of evapotranspiration. In urbanized areas, however, impervious surfaces such as roofs, asphalt
paved roads and parking lots prevent precipitation from naturally soaking into the ground. Instead, the water runs rapidly into storm drains,
municipal sewers and drainage ditches into streams, rivers and lakes and on its way it picks up pesticides, road salts, heavy metals, oils,
bacteria, and other harmful pollutants and transports them through municipal sewers into streams, rivers and lakes.  The sheer force and
volume of polluted runoff causes:
  •   Increased downstream flooding risks
  •   River bank and bed erosion
  •   Increased turbidity
  •   Aquatic Habitat destruction
  •   Changes in the stream flow regime
  •   Combined sewer overflows
  •   Infrastructure damage
  •   Contaminated streams, creeks, rivers & lakes

In order to mitigate the undesirable impacts of urbanization on watercourses and associated infrastructure stormwater management
practices need to be implemented:
  •   To preserve the natural hydrologic balance in newly developing areas and re-establish it, wherever possible, in already developed
  •   To protect and enhance quality of stormwater discharged to lakes and streams; and
  •   To reduce the volume and frequency of combined sewer overflows in older urban areas.

The Stormwater Management Criteria was developed based on the principle that the establishment of appropriate, effective, and
sustainable Stormwater Management practices requires a solid understanding of the form, function, and interrelation of the water resources
and natural heritage systems.

There are numerous practices that can be incorporated into a proposed development. Stormwater Management practices that take an
integrative treatment train approach are essential ingredients for implementation of successful stormwater management strategies.

A Stormwater Management plan must consider two scales of precipitation events:
  • Stormwater Management of large events is needed to prevent increased flood risk and undue inundation of natural systems; and,
  • Stormwater Management of natural or predevelopment hydrology is needed to minimize the volume of runoff leaving a site, which will
    reduce the dependence of developments on downstream infrastructure, respect the sensitivities of natural receiving systems, and
    continue the replenishment of groundwater resources.

Stormwater Management of water quality is critical to minimize the potential for the contaminants generated by our communities to harm the
surrounding environment. Although separate approaches have been provided for flood protection, water quality, erosion control, and water
balance, it should be emphasized that achieving the required design criteria for all of these categories will be dependent upon minimizing
the impact that urbanization has on the water balance. Urbanization, if not dealt with appropriately, will result in significant alteration of the
natural water balance. This, in turn, can cause watercourses, and other natural features, to experience less water during dry weather
periods. It can also reduce the amount of rainfall available to recharge groundwater, sustain aquifers, and maintain ecological processes
dependent on groundwater discharge. It can also increase surface runoff, degrade water quality, and aggravate erosion. Designing a
Stormwater Management System that manages both peak flows and the volume of runoff through encouraging water to infiltrate into the
ground, evapotranspire, and/or be re-used, is critical to sustaining surface and groundwater inputs to natural features that rely on that
surface and groundwater regime. Managing the stormwater balance will therefore be paramount if appropriate design criteria are to be met
for flood protection, water quality, erosion control, and water balance.

Rapid urban expansion, increased traffic, ageing infrastructure, greater climatic variability, and the need for enhanced sustainability of
urban water resources pose significant challenges to conventional stormwater management. Innovative approaches are needed in order to
mitigate the risk of flooding, pollution, and aquatic ecosystem degradation, and enhance beneficial uses of urban waters.  No single
innovative measure is adequate under all circumstances, and a multibarrier approach is deemed to be most effective. Examples of
innovations at the property level include harvesting roof runoff and reusing water, managing rainwater by infiltration in swales and into soils
in bioretention areas, minimizing impervious surfaces, and using pervious pavement. At the neighbourhood level, runoff impacts are
mitigated by designing roads without curbs, gutters, and drain pipes, and diverting runoff into infiltration channels, swales, and wetlands.
Creating roads and parking lots with pervious pavement and draining runoff from such surfaces into infiltration basins is also discussed.
Among stormwater quality source controls, potential effects of street sweeping on runoff quality enhancement were assessed. New
innovations at the watershed scale include:
  • the creation of wideriparian buffer zones that can detain water, remove sediments, and mitigate nutrient export and other pollutant
  • the minimization of channelization of streams and rivers, and
  • the designation of floodwater storage areas.

Stormwater management should be understood and incorporated into development designs since proper stormwater mamangement
efficiently achieve both development and environmental goals in the most cost effective manner. When unusual circumstances or complex
problems arise, our expert stormwater management specialists identify such conditions and propose alternative solutions consistent with
good planning, engineering practices, and scientific principles. The impacts from development occur both during construction and after the
development is complete. The conversion of pervious land to impervious surfaces results in increased rate and volume of stormwater runoff,
reductions in groundwater recharge and reduction of evapotranspiration. These new impervious surfaces change the hydrologic
characteristics of the landscape by reducing infiltration into the soil and evapotranspiration from vegetation which results in a dramatic
increase in the rate and volume of stormwater runoff. New impervious surfaces, compaction of soils, and loss of native vegetation reduces
the amount of precipitation that infiltrates into the ground. Uncontrolled, the impacts of development on stormwater runoff can lead to
increased flooding, degraded water quality, stream channel erosion, hydrologic modifications, and destruction of sensitive habitats and
landscapes. Properly designed and implemented stormwater mamangement facilities can mitigate these impacts.

Stormwater Management Principles
  • Control and, to the extent practical, eliminate water, soil, noise and air pollution to safeguard the natural and human environment.
  • Protect and improve surface water quality, wherever possible.
  • Protect groundwater quality and quantity.
  • Provide stormwater management facilities that are efficient, and minimize life cycle costs.
  • Maintain the natural hydrologic cycle and function of the watersheds through a range of mechanisms through implementation of Low
    Impact Development (LID) stormwater management practices and principles.
  • Prevent increased risk of flooding and stream erosion.
  • Use the treatment train approach to reduce runoff volume and to treat stormwater runoff on-site through the use of source, conveyance
    and end-of-pipe controls.
  • All newly developing or re-developing areas must assess their potential impacts on local and regional flooding and mitigate
  • All stormwater system designs for water quality treatment shall be in accordance with the most current Ministry of the Environment
    Stormwater Management Planning and Design Manual (MOE SWM Manual) and shall use the treatment train approach.
  • Enhanced water quality treatment shall be provided as defined by the MOE SWM Manual.
  • Design shall consider the entire uncontrolled drainage area and external flows.
  • Minor Systems shall be sized to capture and convey the 5 Year Storm.
  • Major Systems shall be sized to capture and convey the Regulatory Storm to a safe outlet without flooding adjacent properties and
    should provide a minimum of 300 mm of freeboard from the maximum water surface elevation of the major system flow path to the
    minimum opening of structures.
  • Hydraulic Grade Line in the storm sewer for the 100 year storm is a minimum of 300 mm below the basement footing elevation.

The Stormwater Management Report provides details and supporting calculations associated with the detailed design of the minor and
major drainage system and the required source, conveyance and end-of-pipe controls required to achieve the criteria established in the
Neighbourhood Functional Servicing and Stormwater Report. It also provides design details for infrastructure to confirm that the design
conforms to municipal standards. The Stormwater Management Report also includes the Monitoring Plan and the Operations and
Maintenance plan.

The Stormwater Management Reports in accordance with legislation and acts for:
  • Watercourses and Existing Infrastructure (i.e., Culverts and Bridges, Roads)
  • Erosion and Sediment Control
  • Flood Damage Control
  • Pollution Prevention
  • Fisheries

When preparing a stormwater management plan the following key acts and regulations may apply:
Federal Acts and Regulations:
  • Federal Fisheries Act
  • Species at Risk Act (SARA)
  • Navigable Waters Protection Act (NWPA)
  • Canadian Environmental Assessment Act.

Provincial Acts and Regulations:
  • Conservation Authorities Act (incl. Ontario Regulation 166/06)
  • Regulation of Development, Interference with Wetlands and Alterations to Shorelines and Watercourses
  • Endangered Species Act
  • Drainage Act
  • Provincial Policy Statement - Natural Hazard Land Policies, Water Quality and Quantity Policies
  • Lakes and Rivers Improvement Act
  • Environmental Protection Act
  • Ontario Water Resources Act
  • Ontario Environmental Assessment Act
  • Planning Act
  • Public Land Act
  • Municipal Act
  • Greenbelt Act
  • Oak Ridges Moraine Conservation Act
  • Ontario Planning and Development Act (Seaton)
  • Places to Grow Act
  • Provincial Secondary Land Use Policy
  • MTO Drainage Management Policy
  • Elements of Common Law -Natural Watercourses (Riparian Rights and Obligations), Surface or Sheet Flow, Subsurface Flow

Municipal Regulations/By-laws:
  • Municipal Zoning By-law for the area of interest
  • Fill and Topsoil Disturbance By-law
  • Noise By-law
  • Tree Protection By-law

Stormwater Drainage System Design Guidelines
Well-designed stormwater conveyance systems are critical for ensuring that stormwater is safely conveyed away from roads and structures
to appropriate drainage outlets. Municipalities strive to ensure that the drainage systems for new developments are robust and designed to
the highest standards of performance. For greenfield development a dual drainage system analysis shall be completed to demonstrate that
the municipal requirements for major and minor system conveyance and the hydraulic grade line are being met.
For infill/redevelopment sites the proponent shall demonstrate through a dual drainage system analysis that the downstream minor and
major system has sufficient capacity to safely accommodate design flows from point of connection of the development site to an existing

The minor system conveys urban drainage from relatively “minor” storms having a return period of 5 years. These works typically consist of
drainage pipes, catchbasins, roadway gutters and swales, enclosed conduits and roof leaders. Their purpose is to prevent frequent
flooding of road surfaces, parking lots and parks.

Municipalities will not allow development to proceed until adequate provision, in the form of storm sewers, has been made available. Rural
development will also require adequate provision for storm drainage; however it may not require storm sewers.
The minor system, comprised of street gutters, catchbasins and storm sewers, shall be designed to convey the 1 in 5 year flow without
exceeding 80% capacity. Flow in a subcritical condition – supercritical flow in sewers will not be allowed.

Ensure the Hydraulic Grade Line (HGL) during the 100 year storm is a minimum of 300 mm below the basement footing elevation.
If the outlet of the storm sewer system is submerged during the 5 year and 100 year events, the hydraulic analysis used to size the pipes
should account for backwater effects to ensure that the municipal conveyance and HGL requirements are met. For sewersheds larger than
40 hectares, or with complicated hydraulics, a dynamic computer model is used.

In areas where the capacity of the receiving storm sewer system is constrained, the site will still need to provide the required level of service
for the storm sewer system on-site. However, there will be an additional requirement that the capacity of the existing storm sewer system is
assessed to determine the required release rate from the site to ensure that there are no impacts to the receiving system. If the allowable
release rate is less than the 1 in 5 year flow, the site will be required to provide on-site storage to control the minor system flow to the
capacity of the existing, receiving storm sewer system. Notwithstanding, storm sewers designed to convey the 1 in 5 year flow will be
required in all cases.

Hydraulic analysis of the proposed and existing storm sewer system shall provide hydraulic grade lines for the 1 in 5 year standard and 1 in
100 year standard. Sewer capacities are computed using the Manning’s Equation. Storm sewers are designed to convey the 1 in 5 year
flow at 80% capacity flowing in a subcritical condition. The minimum allowable size for a storm sewer is 300 mm diameter. The minimum
full bore velocity permitted in storm sewers is 0.8 m/s. The maximum full bore velocity permitted in storm sewers will be 5 m/s.
Where velocities in excess of 3 m/s are proposed, additional design factors shall be taken to protect against pipe displacement, scouring,
erosion, and hydraulic jumps.

The minimum grade on storm sewers is half a percent (0.5%). The minimum slope of the upstream leg of all storm sewers shall be one
percent, unless future developments upstream cannot accommodate this grade. For replacement of pipe sections of existing storm sewer
systems, a minimum flow velocity of 0.8 m/s shall be achieved.

Both rigid and flexible pipe are permitted in the construction of storm sewer systems including municipal service connections and
catchbasin leads. These materials include reinforced concrete, polyvinyl chloride and high density polyethylene. However, the bedding
design must be compatible with the type of pipe material used. Rigid pipe is recommended in areas of high utility congestion, when
bedding may be undermined in the future. External drop pipes will be provided when the difference in invert elevations is greater than 600
mm. The external drop pipe will be one size smaller than the sewer line – minimum 200 mm diameter.

Our Stormwater Management Engineers adhere to the following guidelines:
  • Endeavor to keep entrance and exit velocities equal. In order to reduce the amount of drop required, the engineer will try to restrict the
    change in velocity from one pipe to another in a maintenance hole to less than 0.6 m/s.
  • No acute interior angles will be allowed.
  • No decrease in pipe diameter from a larger size upstream to a smaller size downstream will be allowed, regardless of an increase in
  • When an increase in pipe size occurs at the downstream side of the storm maintenance hole, match obvert elevations of the incoming
    and outgoing pipes or have incoming pipe obverts higher than outgoing pipe obverts.

The maximum change in direction for pipe sizes 675 mm and larger is 45 degrees. For 675 mm and larger diameter pipes where the
change in direction is greater than 45 degrees, additional maintenance holes 1200 mm in diameter will be required to reduce the angle.
The actual size of the storm service connection required for non-residential, commercial, institutional, and high rise condominiums is
determined by the maximum flow permitted from the development. The minimum diameter and grade of a storm service connection is 150
mm diameter at 2 percent slope. Where the storm service connection is required to be an orifice tube, smaller pipe diameters may be
acceptable. Municipalities require a control maintenance hole located on the subject property, as close to the property line as possible. This
requirement applies to all multi-family, commercial, industrial and institutional blocks. Catchbasins will be provided to collect drainage from
both pervious and impervious areas. The spacing and design of catchbasins shall be as per the Municipal Development Control Design
Standards. In designing the stormwater collection system the engineer will ensure that the number of catchbasins connected to each
section of sewer is appropriate so that the minor system is not overloaded causing issues with the hydraulic grade line in the receiving

New outfalls discharging to watercourses are designed to prevent erosion. They are blended into the natural surroundings, in an
aesthetically pleasing manner to the greatest extent possible. Pipe exit velocities shall not impart additional erosion potential to the
streambed and banks. In addition, the outfall shall be adequately protected from erosive forces in the receiving watercourse to prevent
scouring and undermining. Outfalls shall not discharge at the top of valley walls.

The proponent should position the outlet to minimize the angle at which flow from the outfall ties into the watercourse. Outfall channels
should join a watercourse at no more than 90 degrees, with angles less than 45 degrees preferred. Wherever possible, outfalls should be
located in geomorphically stable locations to protect against impacts from anticipated planform adjustment of the watercourse. Storm
sewer outfalls to regulated watercourses require a permit from the Conservation Authority. Storm sewer outfall design is to be submitted to
the Municipality as part of the full engineering submission.

Outfalls to natural watercourses should discharge at or above the average water elevation of the watercourse. If high water levels cause the
submergence of the outlet, the impact of the submergence on the sewer system must be assessed in the hydraulic design of the storm
sewer. The obvert of the outlet shall be above the 25 year flood elevation of the receiving channel. Storm sewer outfalls discharging directly
to Lake Ontario will need to consider the potential problem of dynamic beaches and the potential obstruction of the outlet .The outfall’s
invert should be located above the 100 year lake elevation of 75.7 m.  An access road with a minimum width of 4 m and cross fall of 2%
should be provided to outfalls . Should the outfall be within a fenced area, gate access shall be provided. Outfalls shall be provided with
safeguards to prevent entry by unauthorized personnel into the outfall. Ontario Provincial Standard Drawings (OPSD), should be followed to
determine what outfall sizes require grates to prevent unauthorized entry. Grates shall be installed with means for locking. Provisions must
be made for opening or removing the grate for cleaning purposes. Grates should be designed to break away or swing open under extreme
hydraulic loads due to blockage. Outfalls should be made as safe as possible by utilizing fencing along the headwalls and wingwalls to
prevent accidental falls. Submerged outfalls need to be specifically designed to withstand freeze-thaw cycles and ice dams.
In order to minimize the flow rate from foundation drains, piezometer tests shall be completed prior to design and construction to determine
the seasonal high water level. Foundation elevations should then be set 500 mm higher than the seasonally high water table.Lots shall be
constructed with a storm sewer extension from the storm sewer system to the surface or subsurface adjacent the building. Flow collecting in
the foundation drain shall be pumped to the surface (or subsurface) using a sump pump and into the storm sewer extension and then
conveyed to the storm sewer. A benefit of this configuration is the ability to discharge flow from foundation drains into the storm sewer while
eliminating the risk of basement flooding and avoid surface discharge and nuisance flooding. Flow collecting in the foundation drain shall
be pumped to the surface using a sump pump and then conveyed overland via lot drainage to the street or surface drain.
Infill development projects will consider direct connection of the roof leaders and foundation drains on a site specific basis, but this
generally will not be permitted. For those projects, there will be no direct connection of foundation drains or roof leaders to the minor system.

Flows in excess of the minor system capacity (i.e., during periods of surcharging or higher intensity events) are referred to as the major
system flow. The major system inherently comprises the minor system, as well as the overland route followed by runoff not captured by the
minor system (i.e., either due to excessive flow or operational failures). Common elements of the major system include roadways, swales,
ponds, dedicated blocks, outfall channels, natural streams and valleys. Major system flow paths shall be in public ownership. In extenuating
circumstances major system flow paths may be allowed on private property provided that an easement in favour of the municipality is
provided at the Owner’s cost.

The major system shall safely convey drainage from the Regulatory Storm, defined as the larger of the 100 year storm or the Regional
Storm, to an appropriate outlet without causing damage to private property and with minimum inconvenience to the public. Calculations and
model results (i.e., OTTSWMM or PCSWMM) must be provided to demonstrate that the overland flow route has sufficient capacity to
convey this flow. Where the major system is receiving flow from a stormwater management facility it must be sized to convey the flow from
the uncontrolled Regulatory storm (i.e., the peak flow into the pond). The extent and top elevation of the major system flow path are to be
shown on the grading plan drawings.

In all cases, the proponent of a development site shall investigate and determine the direction and hydraulic capacity of the conveyance
path for the existing major system flow from the site to a watercourse. The purpose of this investigation is to determine if a suitable overland
flow route of sufficient hydraulic capacities exists, which is acceptable to the Municipality.

If the proposed major system overland flow route is accepted by the Municipality, storm runoff is allowed to discharge off-site. If no
approved or adequate overland flow route exists, then all events up to the Regulatory Storm must be detained on-site and released at the
allowable release rate into the minor system.

The overland flow (major) system within the subject development site shall be designed to accommodate and/or convey the major storm
flow, that is, the rainfall runoff resulting from the subject site and any external tributary areas using the Regulatory Storm without causing
flood damage to proposed and adjacent public and private properties. Overland flow routes discharging to watercourses shall be designed
to ensure the long-term stability of the overland flow path and to prevent erosion to the receiving system. They shall be designed to convey
the uncontrolled Regulatory storm flow, defined as the larger of the 100 year or Regional storm flow, to the watercourse. Prior to entering the
receiving system the overland flow route should incorporate measures to dissipate energy. To the greatest extent possible they shall be
blended into the natural surroundings, in an aesthetically pleasing manner. Exit velocities shall not impart additional erosion potential to the
streambed and banks. Major systems shall not outlet at the top of valley walls.

The proponent should position the outlet to minimize the angle at which the overland flow route ties into the creek. Overland flow routes to
regulated watercourses require a permit from the Conservation Authority. Notwithstanding the MTO’s drainage policy and guidelines, it is
required that new roadway culverts and bridges have sufficient capacity to pass the Regulatory Flood in order to avoid adverse backwater

Allowable Regulatory storm flood depths and velocities on roadways should be determined based on the standards within the current
version of the Ontario Ministry of Natural Resources Natural Hazards Technical Guidelines.

Storm Drainage System Design
It must be shown that the site provides safe conveyance of both the minor storm and regulatory flows from both the subject site and any
external lands, through the development to a sufficient outlet, with no adverse impact to either the upstream or downstream landowners. A
sufficient outlet constitutes: a permanently flowing watercourse or lake; a public right of way (provided the proponent has obtained written
permission to discharge storm flows from the land owner); or in the case of privately owned lands, a legal right of discharge registered on
title.Any interim servicing conditions should be identified.

Stormwater Management Facility Design
Pre-development conditions must be indicated including: hydrologic parameters used for modelling, and pre-development peak flow rate
for the erosion control event (i.e., 25 mm 4 hour Chicago storm or subwatershed specific criteria) and pre-development peak flow rates for
the 2 year, 5 year, 10 year, 25 year, 50 year, and 100 year design storms for the critical storm distribution and duration (i.e., must look at 1
hour and 12 hour AES distributions) for each sub catchment.

Post-development conditions must be provided including: hydrologic parameters used for modelling, and post-development peak flow rate
and detention time for the erosion control event (ie. 25 mm 4 hour Chicago storm or subwatershed specific criteria) and post-development
peak flow rates for the the 2 year, 5 year, 10 year, 25 year, 50 year, and 100 year design storms for the critical storm distribution and
duration (i.e. must look at 1 hour and 12 hour AES distributions) for each sub catchment. A table summarizing the critical storm analysis
must be included in support of the storm selected for Stormwater management  facility.

The WSEL’s adjacent the site and downstream of the SWM facility outlet structure must be indicated to ensure the appropriate hydraulic
calculations should backwater conditions exist. If required, thermal mitigation measures must be clearly identified and described for any
proposed SWM facility. The water balance methodology must be provided along with input parameters, summary of results, proposed
siting, and functioning of any proposed infiltration measures. It must be demonstrated that sufficient measures are provided to meet the
required level of water quality control per the established guidelines. It must be demonstrated that sufficient measures are provided to
achieve the required level of erosion control per the established guidelines.

Fee: For Residential Projects including Custom Build Homes and Additions - $1,295
For Multi Residential, Commercial, Industrial and Institutional Projects - $2,475.

Call us Anytime - 24 Hours a Day - 7 Days a Week
416 332 1743        TOLL FREE 1 866 373 3315
Text Message: 416 727 8336

Our stormwater management engineers provide stormwater management reports/ plans for properties located in the following municipalities:

City of Brant, City of Brantford, Town  of Haldimand, City of Hamilton, City of Kawartha Lakes, Town of Norfolk, City of Prince Edward, City of Toronto

City of Oshawa, City of Pickering, Municipality of Clarington, Town of Ajax, Town of Whitby, Township of Brock, Township of Scugog, Township of

City of Burlington, Town of Halton Hills, Town of Milton, Town of Oakville

City of Niagara Falls, City of Port Colborne, City of St. Catharines, City of Thorold, City of Welland, Town of Fort Erie, Town of Grimsby, Town of Lincoln,
Town of Niagara-on-the-Lake, Town of Pelham, Township of Wainfleet, Township of West Lincoln

City of Brampton, City of Mississauga, Town of Caledon

City of Cambridge, City of Kitchener, City of Waterloo, Township of North Dumfries, Township of Wellesley, Township of Wilmot, Township of Woolwich

City of Vaughan, Town of Aurora, Town of East Gwillimbury, Town of Georgina, City of Markham, Town of Newmarket, Town of Richmond Hill, Town of
Whitchurch-Stouffville, Township of King


Town of Grand Valley, Town of Mono, Town of Orangeville, Town of Shelburne, Township of Amaranth, Township of East Garafraxa, Township of
Melancthon, Township of Mulmur

City of St Thomas, Municipality of Bayham, Municipality of Central Elgin, Municipality of Dutton/Dunwich, Municipality of West Elgin, Town of Aylmer,
Township of Malahide, Township of Southwold

City of Belleville (Separated), City of Quinte West, Municipality of Centre Hastings, Municipality of Hastings Highlands, Municipality of Marmora and
Lake, Municipality of Tweed,  Town of Bancroft, Town of Deseronto, Township of Carlow/Mayo, Township of Faraday, Township of Limerick, Township of
Madoc, Township of Stirling-Rawdon, Township of Tudor & Cashel, Township of Tyendinaga, Township of Wollaston

Lennox and Addington
Town of Greater Napanee, Township of Addington Highlands, Township of Loyalist, Township of Stone Mills

City of London, Municipality of North Middlesex, Municipality of Southwest Middlesex, Municipality of Thames Centre, Township of Adelaide Metcalfe,
Township of Lucan Biddulph, Township of Middlesex Centre, Township of Strathroy - Caradoc, Village of Newbury

Municipality of Brighton, Town of Cobourg, Municipality of Port Hope, Municipality of Trent Hills, Township of Alnwick/Haldimand, Township of Cramahe,
Township of Hamilton

City of Woodstock,  Town of Ingersoll, Town of Tillsonburg, Township of Blandford Blenheim, Township of East Zorra-Tavistock, Township of Norwich,
Township of South-West Oxford, Township of Zorra

City of Stratford, Municipality of North Perth, Town of St. Marys, Township of Perth East, Township of Perth South, Municipality of West Perth

City of Peterborough, Township of Asphodel-Norwood, Township of Cavan Monaghan, Township of Douro-Dummer, Township of Havelock-Belmont-
Methuen, Township of North Kawartha, Township of Otonabee-South Monaghan, Township of Selwyn, Municipality of Trent Lakes

City of Barrie, City of Orillia, Town of Bradford West Gwillimbury,  Town of Collingwood,  Town of Innisfil, Town of Midland, Town of New Tecumseth,
Town of Penetanguishene, Town of Wasaga Beach, Township of Adjala-Tosorontio, Township of Clearview, Township of Essa, Township of Oro-
Medonte, Township of Ramara, Township of Severn, Township of Springwater, Township of Tay, Township of Tiny

City of Guelph, Town of Erin, Town of Minto, Township of Centre Wellington, Township of Guelph-Eramosa, Township of Mapleton, Township of
Puslinch, Township of Wellington North

Conservation Authorities in Ontario
Catfish Creek, Central Lake Ontario, Credit Valley, Crowe Valley, Essex Region, Grand River,  Halton Region, Hamilton, Kawartha Region, Kettle Creek,
Lake Simcoe Region, Long Point Region, Lower Trent, Niagara Peninsula,    Nottawasaga Valley,   Otonabee Region,  Quinte, Raisin Region, Saugeen
Valley, Toronto and Region

As the grading and storm water management designs are inter-related it is recommended that the engineer and/or engineering firm that
designed the site grading also develop the storm water management scheme.

We have recently prepared Stormwater Management Reports for the following construction projects:
Industrial Warehouse Addition in Mississauga
New Construction of an Industrial Building in Mississauga
New Construction of a Commercial Plaza in Markham
Addition to a Commercial Retail Building in Oakville
Medium Size Condominium Office Building in Mississauga
Construction of an Infill Custom Home in Pickering
Construction of Commercial Condominium Building in Richmond Hill
Construction of a Gas Station with a Convenience Store and a Drive-Through Coffee Shop in Brampton
Construction of a Condominium Retail Commercial Building in Ajax
Construction of a Multi Storey Office Building in Burlington
Construction of a Medical Building in Vaughan
Construction of a High-rise Condominium Apartment Building in Toronto
Construction of a Commercial Retail Plaza in Oshawa
Conversion of a Commercial/Industrial Building as a Private School in North York (Toronto)
Construction of an Infill Custom Home in Etobicoke (Toronto)
Construction of a Small Commercial Condominium Building in Aurora
Construction of an Industrial Condominium Building in Toronto
Construction of a Commercial / Retail Building in Brampton
Construction of a Small Commercial Building in Newmarket
Construction of an Industrial Building in Mississauga
Addition to an Existing Industrial Building in Mississauga
Construction of an Infill Custom Home in Markham
Construction of a Commercial Retail Condominium Building in Oakville
Addition to an Existing Medium Size Office Building in Toronto
Construction of a Commercial Condominium Building in Pickering
Construction of a Custom Build Home in Richmond Hill
Construction of a Banquet Hall Building in Toronto
Construction of a Condominium Retail Commercial Building in Mississauga
Construction of a Restaurant Building in Burlington
Construction of a Condominium Industrial Building in Vaughan
Construction of a High-rise Condominium Apartment Building in Toronto
Construction of a Retail Building in Oshawa
Construction of a Mid-rise Condominium Apartment Building in Toronto
Construction of a Medical Building in Brampton
Construction of a Small Commercial Building in Ajax
Addition to an Industrial Building in Aurora
Construction of a Gas Station with a Car Wash and Convenience Store in Newmarket
Addition to a Commercial Building in Brampton