Stormwater Management Report
Our Licensed Professional Engineers specializing in Stormwater Management offer Stormwater Management Reports to obtain site plan approval and building permits in Ontario including City of Toronto, Durham Region, Halton Region, Peel Region and York Region (Ajax, Aurora, Bolton, Brampton, Clarington, Burlington, Etobicoke, Maple, Markham, Milton, Mississauga, Newmarket, North York, Oakville, Oshawa, Pickering, Richmond Hill, Scarborough, Stouffville, Toronto, Vaughan, Uxbridge, Whitby, Barrie, Bowmanville, Hamilton, Georgetown, Guelph, Stoneycreek, and Woodbridge) and Conservation Authorities including Toronto and Region Conservation Authority, Central Lake Ontario Conservation Authority, Credit Valley Conservation Authority, Conservation Halton, Lake Simcoe Region Conservation Authority, and Hamilton Conservation Authority.
Stormwater refers to rainwater and melted snow that flows over roads, parking lots, lawn and other sites. Under natural conditions, stormwater 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. When an area is converted from a natural area to an urbanized area, the volume of water that runs off the land increases due to the addition of hard (impervious) surfaces. In urbanized areas impervious surfaces such as asphalt pavements and roofs 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. Stormwater runoff is different from wastewater, which flows into sanitary sewers from household drains.
The sheer force and volume of polluted runoff causes:
In order to mitigate the undesirable impacts of urbanization on watercourses and associated infrastructure stormwater management practices need to be implemented:
Rapid urban expansion and associated construction activities are a significant source of stress to the natural environment. Construction activities accelerate natural processes of erosion and sedimentation as vegetation is stripped away and soils are left exposed. Consequently, stormwater runoff from these sites contains high levels of sediment and associated contaminants. Implementation of adequate water quality controls at construction sites is crucial to ensuring downstream receiving waters and aquatic habitats are adequately protected.
Stormwater management involves storing and directing stormwater runoff in urbanized areas to control flooding, erosion and water quality. This practice protects communities, municipal infrastructure (like roads, sidewalks and trails) and local waterways. The objective of stormwater management is to slow the release of stormwater runoff into natural systems.
Soak-away pits/infiltration trenches are to be incorporated into the storm water management design where the geotechnical report indicates the subsurface soils have a minimum percolation rate of 15 mm/hr. The volume of the gallery will be designed to hold the 25 mm storm over the entire proposed roof area. In order to assess feasibility of infiltrating roof runoff, boreholes or test pits must be drilled/excavated (minimum of 5 m below grade). All soak-away pits/infiltration galleries are to have a minimum of two observation wells (for inspection/maintenance purposes). A minimum cover of 1.2 m is required for all infiltration facilities to protect against frost penetration. A minimum of 1 m is required for separation from the bottom of the infiltration facility to the high ground water level. The high ground water level must be identified on the detail. All soak-away pits/infiltration galleries must have an overflow system.
One way of managing stormwater runoff is through the use of stormwater ponds. Stormwater ponds can be ‘dry’- filling up during a storm, or ‘wet’- having a permanent pool of water. These ponds are designed to hold back stormwater and release it slowly to natural waterways. Wet ponds also allow sediment to settle to the bottom of the pond instead of traveling to a local stream. Stormwater management ponds are so well integrated into the landscape that too many people they appear to be natural ponds. However, they do require maintenance to keep them working properly, such as sediment removal or cleaning of catch basins. Sometimes older ponds need to be replaced with newer, more efficient designs.
Without stormwater management, runoff from urbanized areas would flood communities and roads, cause stream erosion and destroy aquatic habitat. In August of 2005, the City of Toronto experienced a major storm event which resulted in the collapse of part of Finch Avenue. The storm was so intense that the Black Creek culvert under Finch Avenue was unable to handle the amount of runoff flowing through it.
More recently, the south end of Don Valley Parkway was flooded in May of 2013. The Don River overflowed its banks and spilled onto the Don Valley Parkway. This caused major delays for the morning commute. Runoff from this storm also caused basement flooding in many homes.
On July 8, 2013, a record breaking 126 mm of rainfall was recorded at Pearson International Airport within a 24 hour period. This was more rainfall than Hurricane Hazel in 1954. This extreme rainfall event cause the closure of highway ramps, parks, and offices, it flooded streets and basements and caused major electrical outages in certain parts of Toronto.
Lakes and local streams also suffer from runoff. Stormwater that rushes uncontrolled from urban pavements causes streams to rise faster and more dangerously than those in rural areas. The force of the water during rain events scours stream bottoms, erodes banks, harms fish habitat and increases pollutants such as phosphorus and heavy metals. Stormwater picks up dirt, oil, grease, road salt, fertilizers, pesticides and bacteria from urbanized areas. During its journey over pavements, stormwater also becomes warmer which is harmful to fish
Stormwater management is required to release runoff into natural waterways slowly, imitating the water cycle before urbanization. Stormwater ponds are also important because they provide an opportunity for sediment (and pollutants attached to the sediment) to become trapped in the pond bottom, rather than moving into the local streams.
Low Impact Development is a stormwater management strategy that seeks to mitigate the impacts of increased runoff and stormwater pollution. Low Impact Development comprises a set of site design strategies and distributed structural best management practices that harvest, filter, evapo-transpire, detain and infiltrate stormwater
Low Impact Development Principles
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 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:
Our price for typical Stormwater Management Report for Multi Residential, Commercial, Industrial and Institutional projects in Ontario including including Toronto (City of Toronto), Hamilton (City of Hamilton), Oshawa (City of Oshawa), Pickering (City of Pickering), Clarington (Municipality of Clarington), Ajax (Town of Ajax), Whitby (Town of Whitby), Brock (Township of Brock), Scugog (Township of Scugog), Uxbridge (Township of Uxbridge), Burlington (City of Burlington), Halton Hills (Town of Halton Hills), Milton (Town of Milton), Oakville (Town of Oakville), Brampton (City of Brampton), Mississauga (City of Mississauga), Caledon (Town of Caledon), Vaughan (City of Vaughan), Aurora (Town of Aurora), East Gwillimbury (Town of East Gwillimbury), Georgina (Town of Georgina), Markham (City of Markham), Newmarket (Town of Newmarket), Richmond Hill (Town of Richmond Hill), Whitchurch - Stouffville (Town of Whitchurch-Stouffville), King (Township of King) is $2,475.
Upon receiving all required documents and information, the stormwater management reports will be ready in 10 business days. Upon receiving all required documents and information, expedited stormwater management reports which can be prepared within 5 business days will be subjected to a 35% surcharge.
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.
As the site grading, erosion control 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.
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We offer Site Grading and Erosion Control Plans and Stormwater Management Reports to obtain site plan approval and building permits in Ontario including including Toronto (City of Toronto), Hamilton (City of Hamilton), Oshawa (City of Oshawa), Pickering (City of Pickering), Clarington (Municipality of Clarington), Ajax (Town of Ajax), Whitby (Town of Whitby), Brock (Township of Brock), Scugog (Township of Scugog), Uxbridge (Township of Uxbridge), Burlington (City of Burlington), Halton Hills (Town of Halton Hills), Milton (Town of Milton), Oakville (Town of Oakville), Brampton (City of Brampton), Mississauga (City of Mississauga), Caledon (Town of Caledon), Vaughan (City of Vaughan), Aurora (Town of Aurora), East Gwillimbury (Town of East Gwillimbury), Georgina (Town of Georgina), Markham (City of Markham), Newmarket (Town of Newmarket), Richmond Hill (Town of Richmond Hill), Whitchurch - Stouffville (Town of Whitchurch-Stouffville), King (Township of King).
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