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Line 142: − [[File:Screenshot 2025-09-22 113355.png|600px|thumb|right|Peak flow reductions of different LID types during frequent rain events. Top left: Grey and green roof at York University; bottom left: permeable pavement, bioretention and asphalt at Seneca College; right: Kortright permeable pavement and asphalt.]] − Line 272:
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→Case Studies
! Pluvial (surface) flooding
! Pluvial (surface) flooding
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[[File:Reflecting-on-the-devastating-2013-storm-mississauga-takes-lead-in-municipal-flood-resilience-the-pointer-be39ea9b.jpg|350px|frameless|center]] Street flooding in Mississauga (The Pointer, 2023)<ref>The Pointer. 2013. Reflecting on the devastating 2013 storm, Mississauga takes lead in municipal flood resilience. https://thepointer.com/article/2023-07-30/reflecting-on-the-devastating-2013-storm-mississauga-takes-lead-in-municipal-flood-resilience</ref>.
[[File:Reflecting-on-the-devastating-2013-storm-mississauga-takes-lead-in-municipal-flood-resilience-the-pointer-be39ea9b.jpg|400px|frameless|center]] Street flooding in Mississauga (The Pointer, 2023)<ref>The Pointer. 2013. Reflecting on the devastating 2013 storm, Mississauga takes lead in municipal flood resilience. https://thepointer.com/article/2023-07-30/reflecting-on-the-devastating-2013-storm-mississauga-takes-lead-in-municipal-flood-resilience</ref>.
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* Caused by intense rainfall that exceeds soil infiltration and storm sewer capacity, especially in urban areas with impervious surfaces.
* Caused by intense rainfall that exceeds soil infiltration and storm sewer capacity, especially in urban areas with impervious surfaces.
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! Fluvial (riverine) flooding
! Fluvial (riverine) flooding
| [[File:Screenshot 2025-09-22 100405.png|350px|frameless|center]]Don River floods DVP (City News, 2024)<ref>City News. 2024. From the scene: Don Valley River floods section of DVP, stranding drivers. https://www.youtube.com/watch?v=fbyaYZy0d0A&t=68s</ref>.
| [[File:Screenshot 2025-09-22 100405.png|400px|frameless|center]]Don River floods DVP (City News, 2024)<ref>City News. 2024. From the scene: Don Valley River floods section of DVP, stranding drivers. https://www.youtube.com/watch?v=fbyaYZy0d0A&t=68s</ref>.
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* Occurs when rivers exceed their capacity due to heavy rain or snowmelt, resulting in water overtopping the banks and flowing into adjacent areas.
* Occurs when rivers exceed their capacity due to heavy rain or snowmelt, resulting in water overtopping the banks and flowing into adjacent areas.
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! Coastal (shoreline) flooding
! Coastal (shoreline) flooding
|[[File:Screenshot 2025-09-19 115121.png|350px|frameless|center]]Lake Ontario floods Toronto Island (Toronto Life, 2017)<ref>Toronto Life. 2017. Flooding on the Toronto Islands is terrible—but also weirdly beautiful. https://torontolife.com/life/flooding-toronto-islands-terrible-also-weirdly-beautiful/</ref>.
|[[File:Screenshot 2025-09-19 115121.png|400px|frameless|center]]Lake Ontario floods Toronto Island (Toronto Life, 2017)<ref>Toronto Life. 2017. Flooding on the Toronto Islands is terrible—but also weirdly beautiful. https://torontolife.com/life/flooding-toronto-islands-terrible-also-weirdly-beautiful/</ref>.
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* Driven by storm surges and lake-level rise due to storm surges or seiches.
* Driven by storm surges and lake-level rise due to storm surges or seiches.
==Modelling Flood Mitigation Potential of Conventional LIDs==
==Modelling Flood Mitigation Potential of Conventional LIDs==
[[File:Screenshot 2025-09-22 113355.png|700px|thumb|right|Peak flow reductions of different LID types during frequent rain events. Top left: Grey and green roof at York University; bottom left: permeable pavement, bioretention and asphalt at Seneca College; right: Kortright permeable pavement and asphalt.]]
TRCA conducted [[modeling]] to evaluate the capacity of different stormwater management measures (LID and Ponds) to mitigate impacts of development on the peak flow and runoff volume. A sub-catchment in Humber River was selected that has an area of 35.7 ha. The existing land use in the sub-catchment is agriculture and the proposed future land use is employment land with 91% total imperviousness.
TRCA conducted [[modeling]] to evaluate the capacity of different stormwater management measures (LID and Ponds) to mitigate impacts of development on the peak flow and runoff volume. A sub-catchment in Humber River was selected that has an area of 35.7 ha. The existing land use in the sub-catchment is agriculture and the proposed future land use is employment land with 91% total imperviousness.
===Peak Flow===
===Peak Flow===
*The 25 mm on-site retention using LID measures reduced post-development peak flows generated from 2 to 5 year design storms by over 26%,
*The 25 mm on-site retention using LID measures reduced post-development peak flows generated from 2 to 5 year design storms by over 26%,
*For 50 and 100 year design storms it reduces only 4% and 1% respectively.
*For 50 and 100 year design storms it reduces only 4% and 1% respectively.
# Smart blue roof systems can regulate rooftop runoff by storing and controlling the release of rainwater
# Smart blue roof systems can regulate rooftop runoff by storing and controlling the release of rainwater
# In addition to peak flow control, blue roof systems can facilitate runoff reduction through rainwater reuse and evaporative rooftop cooling
# In addition to peak flow control, blue roof systems can facilitate runoff reduction through rainwater reuse and evaporative rooftop cooling
===Example 5: [https://sustainabletechnologies.ca/app/uploads/2020/09/CVC-Glendale-Rain-Garden-Case-Study.pdf Glendale Public School Rain Garden]===
===Example 5: [https://sustainabletechnologies.ca/app/uploads/2020/09/CVC-Glendale-Rain-Garden-Case-Study.pdf Glendale Public School Rain Garden]===