Difference between revisions of "Construction: pretreatment and inlet"
Jump to navigation
Jump to search
Line 3: | Line 3: | ||
'''Construction Steps:''' | '''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: | *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” | *[[Vegetation]]: Follow the guidance shown below in the section “Plant Material Verification and Installation” | ||
*Curbing: Follow the guidance shown above in the section “Curbing”. | *[[curb cuts|Curbing]]: Follow the guidance shown above in the section “Curbing”. | ||
*Aggregate: Follow the guidance shown above in the section “Stone reservoir”. | *[[Aggregates|Aggregate]]: Follow the guidance shown above in the section “Stone reservoir”. | ||
<gallery mode="packed" widths=300px heights=300px> | <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. (Photo Source: CVC, 2021) | 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) |
Revision as of 22:13, 22 September 2022
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”.
Proprietary pre-treatment device[edit]
- 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.
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(s): Pretreatment and Pretreatment features.