Changes

==LID Design for Flood Control==

==LID Design for Flood Control==

[[File:Screenshot 2025-09-22 114031.png|600px|thumb|right|Wet pond: The permanent pool provides water quality control, while the ‘active storage’ above the permanent pool provides temporary storage and slow release to reduce peak flows, stream channel erosion control, and flooding. Wet ponds do not provide runoff reduction or thermal mitigation benefits (MOE, 2003)<ref>Ontario Ministry of Environment. 2003. Stormwater Management Planning and Design Manual. https://www.ontario.ca/document/stormwater-management-planning-and-design-manual/stormwater-management-plan-and-swmp-design</ref>.]]

[[File:Screenshot 2025-09-22 114031.png|600px|thumb|right|Wet pond: The permanent pool provides water quality control, while the ‘active storage’ above the permanent pool provides temporary storage and slow release to reduce peak flows, stream channel erosion control, and flooding. Wet ponds do not provide runoff reduction or thermal mitigation benefits (MOE, 2003)<ref>Ontario Ministry of Environment. 2003. Stormwater Management Planning and Design Manual. https://www.ontario.ca/document/stormwater-management-planning-and-design-manual/stormwater-management-plan-and-swmp-design</ref>.]]

Kim & Han (2008)<ref>Kim, Y., & Han, M. (2008). Rainwater storage tank as a remedy for a local urban flood control. Water Science and Technology: Water Supply, 8(1), 31-36.</ref> and Han & Mun (2011)<ref>Han, M. Y., & Mun, J. S. (2011). Operational data of the Star City rainwater harvesting system and its role as a climate change adaptation and a social influence. Water Science and Technology, 63(12), 2796-2801.</ref> conducted studies in Seoul, South Korea, to assess the extent to which the installation of rainwater harvesting cisterns could help mitigate existing urban flooding problems without expanding the capacity of the existing urban drainage system. System operational data showed that 29 mm of rainwater storage per square meter of impervious area (3000 m3 cistern in this instance) provided sufficient storage for a one in 50 year period storm without the need to upgrade downstream sewers designed to 10 year storm capacity. Stormwater chambers, [[infiltration chambers]], [[bioretention]] and other LID systems designed with large volumes of temporary storage could have similar benefits, while also reducing runoff volumes and providing other co-benefits.

Kim & Han (2008)<ref>Kim, Y., & Han, M. (2008). Rainwater storage tank as a remedy for a local urban flood control. Water Science and Technology: Water Supply, 8(1), 31-36.</ref> and Han & Mun (2011)<ref>Han, M. Y., & Mun, J. S. (2011). Operational data of the Star City rainwater harvesting system and its role as a climate change adaptation and a social influence. Water Science and Technology, 63(12), 2796-2801.</ref> conducted studies in Seoul, South Korea, to assess the extent to which the installation of rainwater harvesting cisterns could help mitigate existing urban flooding problems without expanding the capacity of the existing urban drainage system. System operational data showed that 29 mm of rainwater storage per square meter of impervious area (3000 m3 cistern in this instance) provided sufficient storage for a one in 50 year period storm without the need to upgrade downstream sewers designed to 10 year storm capacity. Stormwater chambers, [[infiltration chambers]], [[bioretention]] and other LID systems designed with large volumes of temporary storage could have similar benefits, while also reducing runoff volumes and providing other co-benefits.

When designing LID for flood control it is important to consider the need to not only provide extended detention storage but also a means for water to enter the storage reservoir quickly.  Incoming flows should also be pre-treated to avoid clogging of media and drainage pipes.  Such [[pre-treatment]] can be achieved through [[Ogs|OGS]], catchbasin inserts or high flow cobble [[inlets]], among others.  The storage media in the LID facility should have a high void ratio to reduce the potential for [[clogging]] with fine sediment that may bypass the inlet pre-treatment controls.

When designing LID for flood control it is important to consider the need to not only provide extended detention storage but also a means for water to enter the storage reservoir quickly.  Incoming flows should also be pre-treated to avoid clogging of media and drainage pipes.  Such [[pre-treatment]] can be achieved through [[Ogs|OGS]], catchbasin inserts or high flow cobble [[inlets]], among others.  The storage media in the LID facility should have a high void ratio to reduce the potential for [[clogging]] with fine sediment that may bypass the inlet pre-treatment controls.

[[File:Illicit-discharge.png|250px|thumb|center|Keeping inlets clear via pre-treatment and maintenance helps take advantage of the full storage capacity of the LID feature (City of Clearwater, 2025)<ref>City of Clearwater. 2025. Help Keep Clearwater's Stormwater Clean. https://www.myclearwater.com/My-Government/0-City-Departments/Public-Works/Help-Keep-Clearwaters-Stormwater-Clean</ref>.]]<br clear="all" />

[[File:Illicit-discharge.png|250px|thumb|center|Keeping inlets clear via pre-treatment and maintenance helps take advantage of the full storage capacity of the LID feature (City of Clearwater, 2025)<ref>City of Clearwater. 2025. Help Keep Clearwater's Stormwater Clean. https://www.myclearwater.com/My-Government/0-City-Departments/Public-Works/Help-Keep-Clearwaters-Stormwater-Clean</ref>.]]<br clear="all" />

==Case Studies==

==Case Studies==