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Line 177: − ===Example 1: Costco Distribution Centre=== − Costco Distribution Centre located within Block 59, Vaughan. The site has 26.4 ha and the land use is commercial site with an average site imperviousness of approximately 90%; − − '''Stormwater Management Criteria''' − *Quantity Control – meet Humber River Unit Release Rates; − *Quality Control – 80% TSS Removal; − *Water Balance – Best Efforts to match post to pre; − *Erosion control, 25mm erosion storm released over 72 hours, on-site retention of the first 5mm of rainfall − − '''Stormwater Management Strategy''' − #A series of sub-surface infiltration chambers providing on-site retention/infiltration of the 5mm storm, water balance to reduce runoff volumes, and storage of the 100-year storm; − #Quality treatment provided using an oil/grit separator immediately upstream of each of the infiltration chambers, filtration through the infiltration chamber, and finally a stormwater management facility provided prior to discharging from the site. − #Final erosion control provided within the stormwater management facility, controlling release rates to maintain the existing condition erosion exceedance values. − #Final design required both LIDs to reduce the overall runoff volumes, but also sub-surface storage chambers to provide quantity control for rare storm events up to the 100-year design storm. Due to large area required for truck parking, limited opportunities for more landscaping to promote [[evapotranspiration]], runoff volumes increased beyond ability of LIDs to negate the need for quantity control. − − − ===Example 2. West Gormley, Town of Richmond Hill=== − Residential development consisting of low and medium density land-use is implemented on the site. Average site imperviousness is approximately 60%; − '''Stormwater Management Criteria'''+ − *Quantity Control – Rouge River – match post development peak flow rates to pre-development; − *Quality Control – 80% TSS Removal; − *Water Balance –Match post development water budget to pre-development; − *Erosion Control – Southern portion of site discharging to a natural dry valley feature. Feature and contributing drainage area consists of very sandy soil, producing no runoff until a greater than 25-year storm event. − :Therefore, development discharging to dry valley needed to match runoff volumes, or have no runoff from development area for storms less than 25-year design storm. − − '''Stormwater Management Strategy''' − #Use a combination of increased topsoil depths, perforated storm sewers, stormwater management facility, and an infiltration facility to provide quality, quantity, and reduce runoff volumes to match pre-development. − #Even with favorable soils and maximum use of infiltration techniques, site still requires quantity control storage for large storm events. − − − − The size of the site is 0.53 ha. The site currently developed as commercial and residential. Proposed high rise (11-storeys) residential building with 3 levels of underground parking Proposed average site imperviousness is 90% (excluding uncontrolled buffer area 0.22 ha) − − '''Stormwater Management Criteria''' − *Quantity Control – not requirement as drains to Lower Humber River − *Quality Control – 80% TSS Removal − *Water balance/Erosion Control – Retention of 5 mm event on-site − − '''Stormwater Strategy''' − #Large portion of the roof proposed as green roof and cistern proposed in underground parking to capture remaining volume to meet 5 mm target. Water to be used for irrigation and carwash stations. − #Quality target achieved as majority of site is ‘clean’ roof water or directed to pervious area. Underground storage tank provided to satisfy municipal release rates to receiving storm sewer system. − #Final design required both LIDs to reduce the overall runoff volumes, but also sub-surface storage chambers to provide quantity control to meet municipal requirements. − #Due to underground parking limited opportunities for infiltration LIDs but used green roof to promote evapotranspiration, and cistern to reduce runoff volumes. − − − ===Example 4: [https://sustainabletechnologies.ca/app/uploads/2015/07/Honda_TechBrief_July2015.pdf Honda Canada Head Office]=== Line 245:
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→Case Studies
Below are examples of where LID practices with quantity control components have been used for achieving flood control.
Below are examples of where LID practices with quantity control components have been used for achieving flood control.
===Example 1: [https://sustainabletechnologies.ca/app/uploads/2015/07/Honda_TechBrief_July2015.pdf Honda Canada Head Office]===
===Example 3: 3775-4005 Dundas St West (includes 2-6 Humber Hill Ave), Toronto===
[[File:Screenshot 2025-09-24 121112.png|400px|thumb|right|Locations of LID features within the Honda Canada Head Office study site in Markham, Ontario. Water levels were monitored at the standpipe locations and flow rates were measured at the outlets to the northeast (NE), southeast (SE) and west (W) catchments (STEP, 2015) <ref name=HONDA>STEP. 2015. Hydrologic Assessment of LID Honda Campus, Markham, ON. https://sustainabletechnologies.ca/app/uploads/2015/07/Honda_TechBrief_July2015.pdf</ref>.]]
[[File:Screenshot 2025-09-24 121112.png|400px|thumb|right|Locations of LID features within the Honda Canada Head Office study site in Markham, Ontario. Water levels were monitored at the standpipe locations and flow rates were measured at the outlets to the northeast (NE), southeast (SE) and west (W) catchments (STEP, 2015) <ref name=HONDA>STEP. 2015. Hydrologic Assessment of LID Honda Campus, Markham, ON. https://sustainabletechnologies.ca/app/uploads/2015/07/Honda_TechBrief_July2015.pdf</ref>.]]
[[File:Screenshot 2025-09-24 121338.png|400px|thumb|right|From left to right: Drainage swale and fitness path, biofilter stone trench, permeable surfaces in outdoor eating areas, rainwater cistern, native plantings, and vegetated biofilter (STEP, 2015) <ref name=HONDA></ref>.]]
[[File:Screenshot 2025-09-24 121338.png|400px|thumb|right|From left to right: Drainage swale and fitness path, biofilter stone trench, permeable surfaces in outdoor eating areas, rainwater cistern, native plantings, and vegetated biofilter (STEP, 2015) <ref name=HONDA></ref>.]]
STEP/TRCA conducted a hydrologic monitoring and modelling study of the site in 2012/13 with researchers from The Metropolitan University to assess runoff volume and peak flow reductions. Results showed that, relative to a conventional stormwater approach without LID, runoff was reduced over the study period by between 30% and 35% for the entire site, and by between 58 and 62% in the catchment with a higher density of LID practices. Peak flows were also reduced by 73 to 78%. In the Northeast catchment, 20% of rainfall harvested from the roof was stored and reused for irrigation during the summer months. This reuse volume represented 6% of total site rainfall over 8 months. A hydrologic model calibrated using monitored data showed that the stormwater management system met the design objective of providing quantity control for the post development 100 year storm.
STEP/TRCA conducted a hydrologic monitoring and modelling study of the site in 2012/13 with researchers from The Metropolitan University to assess runoff volume and peak flow reductions. Results showed that, relative to a conventional stormwater approach without LID, runoff was reduced over the study period by between 30% and 35% for the entire site, and by between 58 and 62% in the catchment with a higher density of LID practices. Peak flows were also reduced by 73 to 78%. In the Northeast catchment, 20% of rainfall harvested from the roof was stored and reused for irrigation during the summer months. This reuse volume represented 6% of total site rainfall over 8 months. A hydrologic model calibrated using monitored data showed that the stormwater management system met the design objective of providing quantity control for the post development 100 year storm.
===Example 5: [https://sustainabletechnologies.ca/app/uploads/2020/06/Wychwood-Report.pdf Wychwood Subdivision in Brampton]===
===Example 2: [https://sustainabletechnologies.ca/app/uploads/2020/06/Wychwood-Report.pdf Wychwood Subdivision in Brampton]===
[[File:Screenshot 2025-09-24 122316.png|400px|thumb|right|Map of LID in Wychwood (STEP, 2020)<ref name=WYCHWOOD>STEP. 2020. Wychwood Subdivision, City of Brampton Low Impact Development Infrastructure Performance and Risk Assessment. https://sustainabletechnologies.ca/app/uploads/2020/06/Wychwood-Report.pdf</ref>.]]
[[File:Screenshot 2025-09-24 122316.png|400px|thumb|right|Map of LID in Wychwood (STEP, 2020)<ref name=WYCHWOOD>STEP. 2020. Wychwood Subdivision, City of Brampton Low Impact Development Infrastructure Performance and Risk Assessment. https://sustainabletechnologies.ca/app/uploads/2020/06/Wychwood-Report.pdf</ref>.]]
*Event greater than 30 mm showed peak flow reductions of 74%, with a total volume reduction of 59%
*Event greater than 30 mm showed peak flow reductions of 74%, with a total volume reduction of 59%
*Modelling pre and post development peak flow rates indicated that peak flow targets were met for the 2 to 50 year storms but post development peak flows were *10% greater than pre development peak flows for the 100 year storm.
*Modelling pre and post development peak flow rates indicated that peak flow targets were met for the 2 to 50 year storms but post development peak flows were *10% greater than pre development peak flows for the 100 year storm.
===Example 3: Costco Distribution Centre===
Costco Distribution Centre located within Block 59, Vaughan. The site has 26.4 ha and the land use is commercial site with an average site imperviousness of approximately 90%;
'''Stormwater Management Criteria'''
*Quantity Control – meet Humber River Unit Release Rates;
*Quality Control – 80% TSS Removal;
*Water Balance – Best Efforts to match post to pre;
*Erosion control, 25mm erosion storm released over 72 hours, on-site retention of the first 5mm of rainfall
'''Stormwater Management Strategy'''
#A series of sub-surface infiltration chambers providing on-site retention/infiltration of the 5mm storm, water balance to reduce runoff volumes, and storage of the 100-year storm;
#Quality treatment provided using an oil/grit separator immediately upstream of each of the infiltration chambers, filtration through the infiltration chamber, and finally a stormwater management facility provided prior to discharging from the site.
#Final erosion control provided within the stormwater management facility, controlling release rates to maintain the existing condition erosion exceedance values.
#Final design required both LIDs to reduce the overall runoff volumes, but also sub-surface storage chambers to provide quantity control for rare storm events up to the 100-year design storm. Due to large area required for truck parking, limited opportunities for more landscaping to promote [[evapotranspiration]], runoff volumes increased beyond ability of LIDs to negate the need for quantity control.
===Example 4. West Gormley, Town of Richmond Hill===
Residential development consisting of low and medium density land-use is implemented on the site. Average site imperviousness is approximately 60%;
'''Stormwater Management Criteria'''
*Quantity Control – Rouge River – match post development peak flow rates to pre-development;
*Quality Control – 80% TSS Removal;
*Water Balance –Match post development water budget to pre-development;
*Erosion Control – Southern portion of site discharging to a natural dry valley feature. Feature and contributing drainage area consists of very sandy soil, producing no runoff until a greater than 25-year storm event.
:Therefore, development discharging to dry valley needed to match runoff volumes, or have no runoff from development area for storms less than 25-year design storm.
'''Stormwater Management Strategy'''
#Use a combination of increased topsoil depths, perforated storm sewers, stormwater management facility, and an infiltration facility to provide quality, quantity, and reduce runoff volumes to match pre-development.
#Even with favorable soils and maximum use of infiltration techniques, site still requires quantity control storage for large storm events.
===Example 5: 3775-4005 Dundas St West (includes 2-6 Humber Hill Ave), Toronto===
The size of the site is 0.53 ha. The site currently developed as commercial and residential. Proposed high rise (11-storeys) residential building with 3 levels of underground parking Proposed average site imperviousness is 90% (excluding uncontrolled buffer area 0.22 ha)
'''Stormwater Management Criteria'''
*Quantity Control – not requirement as drains to Lower Humber River
*Quality Control – 80% TSS Removal
*Water balance/Erosion Control – Retention of 5 mm event on-site
'''Stormwater Strategy'''
#Large portion of the roof proposed as green roof and cistern proposed in underground parking to capture remaining volume to meet 5 mm target. Water to be used for irrigation and carwash stations.
#Quality target achieved as majority of site is ‘clean’ roof water or directed to pervious area. Underground storage tank provided to satisfy municipal release rates to receiving storm sewer system.
#Final design required both LIDs to reduce the overall runoff volumes, but also sub-surface storage chambers to provide quantity control to meet municipal requirements.
#Due to underground parking limited opportunities for infiltration LIDs but used green roof to promote evapotranspiration, and cistern to reduce runoff volumes.
==Data Analysis/Modelling==
==Data Analysis/Modelling==