View source for Construction: 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”.
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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. (Photo Source: CVC, 2021)
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. (Photo Source: CVC, 2021)
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. (Photo Source: CVC, 2021)
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[[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>

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P1160102.JPG|Installation of Jellyfish filter and sorbtive media vault at the IMAX bioswale project in Mississauga, ON. (Photo Source: CVC, 2012)
P1160117.JPG|Installation of Jellyfish filter and sorbtive media vault at the IMAX bioswale project in Mississauga, ON. (Photo Source: CVC, 2012)
P1160121.JPG|Installation of Jellyfish filter and sorbtive media vault at the IMAX bioswale project in Mississauga, ON. (Photo Source: CVC, 2012)

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[[Category:Gallery]]

'''Key Inspection Points:'''
*Verify that the correct pre-treatment device ([[pretreatment|jellyfish filter]], [[vegetation]], [[curb cuts|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(s): [[Pretreatment]] and [[Pretreatment features]].