Difference between revisions of "Construction: pretreatment and inlet"
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'''Key Inspection Points:''' | '''Key Inspection Points:''' | ||
*Verify that the correct pre-treatment device (jellyfish filter, vegetation, curbing, etc.) is being installed. | *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 that all components of the pre-treatment device are installed | ||
*Verify correct size and location of pre-treatment device. | *Verify correct size and location of pre-treatment device. | ||
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*Using wrong concrete forms if concrete curbs are part of pre-treatment. | *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]]. | For more information about pre-treatment strategies and their design, visit these page(s): [[Pretreatment]] and [[Pretreatment features]]. |
Revision as of 15:22, 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.