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{{:Sub-base reservoir}}
{{:Base course}}
{{:Construction: stone choker layer}}
{{:Construction: curbing}}
{{:Construction: pretreatment and inlet}}
no edit summary
===Sub-base reservoir===
===Sub-base reservoir===
In permeable pavement systems, the sub-base is the layer of granular material that is laid on the sub-grade. The granular sub-base should be clear, crushed 50 mm stone. See the Permeable pavements: Specifications page for detailed sub-base material specifications. The construction steps, key inspection points, and mistakes to avoid for sub-base reservoir are the same as / similar to the guidance given in the storage reservoir section.
However, depending on the municipality and the design, compaction of the sub-base reservoir may be required. For example, the City of Toronto’s Construction Specification for Permeable Interlocking Concrete Pavers (TS 861) details the following steps for sub-base installation:
#Place sub-base aggregate in 200 mm lifts (maximum)
#Compact each lift with a 9-ton vibratory roller, with two passes in vibratory mode and two passes in static mode, or until there is no visible movement of the aggregate.
#Use a plate compactor for smaller areas that the vibratory roller cannot reach.
===Base course===
===Base course===
In permeable pavement systems, the base course lies on top of the sub-base reservoir. See the Permeable pavements: Specifications page for base material specifications. The construction steps, key inspection points, and mistakes to avoid for the base course are the same as the guidance given in the storage reservoir section.
However, depending on the municipality and the design, compaction of the base course may be required. For example, the City of Toronto’s Construction Specification for Permeable Interlocking Concrete Pavers (TS 861) details the following steps for base course installation:
#Place base course aggregate in 100 mm lifts (maximum)
#Compact each lift with a 9 ton vibratory roller, with two passes in vibratory mode and two passes in static mode, or until there is no visible movement of the aggregate.
#Use a plate compactor for smaller areas that the vibratory roller cannot reach.
==Stone choker layer==
==Stone choker layer==
''INSERT VIDEO: K:\Watershed Management\Integrated Water Management Implementation\Fletchers Creek SNAP\Haggert Ave Road Retrofit\3 - Photos\Construction Overview Presentation\Video--> HaggertAve_Final.MP4''
In LID facilities, a choker layer of ≥ 100 mm depth is recommended to prevent migration of finer filter media into the underlying storage reservoir aggregate. Similar to the storage reservoir material, this aggregate layer should be a washed 5 – 10 mm stone not containing any debris. Installation of aggregate choker layer should not be done when frozen.
Follow the construction guidance shown above in the section “Storage reservoir”
For more information on the choker layer, see the page: [[Choker layer]] and [[OPSS aggregates]].
==Curbing==
==Curbing==
"'INSERT VIDEO FROM HAGGERT AVE: \\Hqcvcfs01\cvc2\Watershed Management\Integrated Water Management Implementation\Fletchers Creek SNAP\Haggert Ave Road Retrofit\3 - Photos\Construction Photos\Site Visit_20201120\Riverstone Construction Haggert Ave Inlet_F.mp4''
It is very important to make sure that the contractor responsible for curb construction understands curb cut designs and elevations. This is often a new technique for contractors, and they may not understand the overall concept of water in the gutter line being directed behind the gutter.<br>
'''Construction Steps:'''
#Place the right forms (rolled curve vs standard) in the inlet location.
#Pour concrete.
#Shape the inlet
#Add the river stone on top of the fresh concrete (if applicable)
#Provide sufficient curing time, according to CSA standard A23.1-09.
[[File:20150618 114542.jpg|thumb|500px|right|Caption]]
[[File:P1160129.JPG|thumb|400px|right|Caption]]
'''Key Inspection Points:'''
*Use of proper curb form by sub-contractor.
*Curb type aligns with design.
*Curb cut location, type and dimension aligns with design.
*Designated concrete wash out is in place and away from LID facility.
'''Mistakes to Avoid:<br>'''
*Elevated curb cuts and reverse slopes (sloping from back of curb towards instead of depressing from gutter line towards the back).
*Wrong curb cut width size.
*Use of wrong curb form.
*Concrete wash out within or upstream of LID facility.
*Ensure curb granular base (granular A) does not spill over into LID infiltration area. If material spills over, remove as best as possible while still maintaining the 2:1 slope for curbing
*Lack of communication to concrete contractor or ready-mix driver explaining the function and importance of protecting the LID feature.
For more information on curb cuts, see these pages: [[Curb cuts]], [[Curb cuts: Gallery]] and [[Bioretention: Streetscapes]]<br>
==Pretreatment and inlet==
==Pretreatment and inlet==
Pre-treatment structures are most cost effective when they slow down incoming flows, collect sediment for easy clean out, and slowly release water to the bioretention facility mitigating erosion. [[Pretreatment]] structures/strategies can include [[curb cuts]], [[Aggregates]], proprietary devices like filters or hydrodynamic separators, vegetation, concrete sumps, membrane filters, overland flow sumps, etc.
'''Construction Steps:'''
*Installation of pre-treatment features will vary based upon type. Similarly, installation timeline will range with type and could occur at excavation and mass grading, curb work or at finishing grade. Given pre-treatment features are typically integrated with the LID inlet coordination amongst multiple sub-contractors is sometime needed. The following details steps for various pre-treatment types:
*Vegetation: Follow the guidance shown below in the section “Plant Material Verification and Installation”
*Curbing: Follow the guidance shown above in the section “Curbing”.
*Aggregate: Follow the guidance shown above in the section “Stone reservoir”.
<gallery mode="packed" widths=300px heights=300px>
IMG_0891.JPG|Aggregate material (rock) installed as the inlet and pre-treatment device in the rain garden at Glendale P.S. in Brampton, ON. The runoff comes from a vegetated swale into the inlet, conveying it into the rain garden.
IMG_0744.JPG|Aggregate material (rock) installed as the inlet and pre-treatment device in the rain garden at Glendale P.S. in Brampton, ON. The runoff comes from a vegetated swale into the inlet, conveying it into the rain garden.
IMG_0788-1.JPG|Aggregate material (rock) installed as the inlet and pre-treatment device in the rain garden at Glendale P.S. in Brampton, ON. The runoff comes from a vegetated swale into the inlet, conveying it into the rain garden.
</gallery>
[[Category:Gallery]]
*Proprietary pre-treatment device:
#Excavate and prepare base for proprietary pre-treatment device according to design.
#Install proprietary pre-treatment device according manufacturer directions.
#Manufacturer representative may need to confirm proper installation and functioning through approved testing and inspection. <br>
<gallery mode="packed" widths=275px heights=275px>
P1160102.JPG|Installation of Jellyfish filter and sorbtive media vault at the IMAX bioswale project in Mississauga, ON.
P1160117.JPG|Installation of Jellyfish filter and sorbtive media vault at the IMAX bioswale project in Mississauga, ON.
P1160121.JPG|Installation of Jellyfish filter and sorbtive media vault at the IMAX bioswale project in Mississauga, ON.
</gallery>
[[Category:Gallery]]
'''Key Inspection Points:'''
*Verify that the correct pre-treatment device (jellyfish filter, vegetation, curbing, etc.) is being installed.
*Verify that all components of the pre-treatment device are installed
*Verify correct size and location of pre-treatment device.
*Verify correct elevation, slope, and footing according to design
*Is it tied into the curb, downspout, or other inlet? Or could happen before the curbing?
*Wet weather performance check:
**Does it work?
**Is water entering the LID facility properly?
**Is sediment and debris accumulating?
**Is it dissipating erosive forces?
'''Mistakes to Avoid:'''
*Pre-treatment component parts are missing
*Grading/elevation errors that deviates from design
**Incorrect pipe inverts causing short circuiting
**Insufficient grade drop or slope into pre-treatment to ensure positive flow of water
**Improper grading from pre-treatment to LID feature inhibiting positive flow
**Insufficient sump depth to account for sediment and debris accumulation
*Using wrong concrete forms if concrete curbs are part of pre-treatment.
For more information about pre-treatment strategies and their design, visit these page: [[Pretreatment]] and [[Pretreatment features]].