Difference between revisions of "Inspection and Maintenance: Permeable Pavement"

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==Inspection and Testing Framework==
==Inspection and Testing Framework==
[[File:Visual indicator bioretention.PNG|thumb|300px|Example of a visual indicator to be used when assessing the condition of a given LID feature. Here we see excessive sediment accumulation at the [[inlet]]/[[curb cut]] of a bioretention cell. Source: (TRCA, 2016).<ref>STEP. 2016. Low Impact Development Stormwater Management Practice Inspection and Maintenance Guide. https://sustainabletechnologies.ca/app/uploads/2016/08/LID-IM-Guide-2016-1.pdf</ref>.]]
{| class="wikitable" style="width: 900px;"
|+'''Visual Indicators Framework - Bioretention/Swales'''
|-
!<br>'''Component'''
!<br>'''Indicators'''
!<br>'''Construction Inspection'''
!<br>'''Assumption Inspection'''
!<br>'''Routine Operation Inspection'''
!<br>'''Verification Inspection'''
|-
|rowspan="2"|'''[[Bioretention: Sizing|Contributing Drainage Area]]'''
|-
|CDA condition
|x
|x
|x
|x
|-
|rowspan="5"|'''[[Inlets|Inlet]]'''
|-
|Inlet/Flow Spreader Structural Integrity
|
|x
|x
|x
|-
|Inlet/Flow Spreader Structural Integrity
|x
|x
|x
|x
|-
|Pretreatment sediment accumulation
|x
|x
|x
|
|-
|Inlet erosion
|
|x
|x
|
|-
|rowspan="4"|'''Perimeter'''
|-
|BMP dimensions
|x
|x
|
|x
|-
|Side slope erosion
|
|x
|x
|
|-
|Surface ponding area 
|x
|x
|
|x
|-
|rowspan="9"|'''[[Bioretention: Filter media|Filter Bed]]'''
|-
|Standing water
|
|x
|x
|x
|-
|Trash
|
|x
|x
|
|-
|Filter bed erosion
|
|x
|x
|
|-
|Mulch depth
|x
|x
|x
|x
|-
|Filter bed sediment accumulation
|
|x
|x
|x
|-
|Surface ponding depth
|x
|x
|
|x
|-
|Filter bed surface sinking
|
|x
|x
|x
|-
|Check dams
|x
|x
|x
|x
|-
|rowspan="4"|'''[[Vegetation|Planting Area]]'''
|-
|Vegetation cover
|x
|x
|x
|x
|-
|Vegetation condition
|
|x
|x
|
|-
|Vegetation composition
|x
|x
|x
|
|-
|rowspan="4"|'''[[Overflow|Outlet]]'''
|-
|Monitoring well condition
|x
|x
|x
|x
|-
|Sub-drain/Perforated pipe obstruction
|
|x
|
|x
|-
|Overflow outlet obstruction
|x
|x
|x
|x
|-
|}<br>
</br>
[[File:Soil testing indicators.PNG|thumb|300px|The image above shows a manual soil corer, a split soil core sampler kit which preserves the soil sample for further testing (i.e., bulk density) and acrylic core sample tubes. All examples of tools to be use for soil characterization testing. Source: (TRCA, 2016).<ref>STEP. 2016. Low Impact Development Stormwater Management Practice Inspection and Maintenance Guide. https://sustainabletechnologies.ca/app/uploads/2016/08/LID-IM-Guide-2016-1.pdf</ref>.]]
{| class="wikitable" style="width: 900px;"
|+'''Testing Indicators Framework - Bioretention/Swales'''
|-
!<br>'''Component'''
!<br>'''Indicators'''
!<br>'''Construction Inspection'''
!<br>'''Assumption Inspection'''
!<br>'''Routine Operation Inspection'''
!<br>'''Verification Inspection'''
|-
|rowspan="6"|'''Testing Indicators'''
|-
|Soil characterization testing
|x
|x
|
|(x)
|-
|Sediment accumulation testing
|x
|x
|x
|x
|-
|Surface infiltration rate testing
|
|x
|
|(x)
|-
|Natural or simulated storm event testing
|
|x
|
|(x)
|-
|Continuous monitoring
|
|x
|
|(x)
|-
|colspan="7" style="text-align: center;" |'''<u><span title=>Note:''' (x) denotes indicators to be used for Performance Verification inspections only (i.e., not for Maintenance Verification inspections) </span></u>
|-
|}

Revision as of 15:58, 18 July 2022

Inspection & Maintenance Guidance of a built vstormwater best management practices that treats the stormwater that falls on them and can be designed to also receive runoff from adjacent impermeable surfaces (e.g., pavements and roofs) as either sheet flow or from a pipe (e.g., roof downspout) connected to the washed gravel base, where captured water is temporarily stored in the base where it later soaks into underlying native soil or sent to a municipal stormsewer/other BMP via underdrains (TRCA, 2016)[1]

Overview[edit]

Permeable Pavement Permeable pavements contain many small openings (i.e., joints or pores) that allow rainfall and snowmelt (i.e., stormwater) to drain through them instead of running off the surface as it does on impervious pavements like conventional asphalt and concrete. An overflow outlet is needed to safely convey flows during flood events. Depending on the permeability of the underlying soil and other constraints, the pavement may be designed with no sub-drain for full infiltration, with a sub-drain for partial infiltration, or with an impermeable liner and sub-drain for a no infiltration practice. The sub-drain pipe may feature a flow restrictor (e.g., orifice cap or valve) for gradually releasing detained water and optimizing the amount drained by infiltration into the underlying soil.

Associated Practices[edit]

  • Permeable Interlocking Pavers (i.e., Block Pavers) – Precast modular units made of concrete, pervious concrete or rubber/plastic composite designed to create open joints between pavers that are filled with fine, washed aggregate and installed on an open graded aggregate (i.e., clear stone) base and sub-base.
  • Permeable Interlocking Grid Systems (i.e., grid pavers) – Precast concrete or manufactured plastic grids with open cells that can be filled with aggregate or a mixture of sand, gravel and topsoil and planted with grass or low-growing ground covers and are installed on an open-graded aggregate base.
  • Pervious Concrete – a rigid pavement installed on an open-graded aggregate base that uses a cementitious binder to adhere aggregate together, similar to conventional concrete, except that the fine aggregate component is minimized or eliminated which results in the formation of connected pores throughout.
  • Porous Asphalt – a flexible pavement installed on an open-graded aggregate base that uses a bituminous binder to adhere aggregate together, similar to conventional asphalt, except that the fine aggregate component is minimized or eliminated which results in the formation of connected pores throughout.

Inspection and Testing Framework[edit]

Example of a visual indicator to be used when assessing the condition of a given LID feature. Here we see excessive sediment accumulation at the inlet/curb cut of a bioretention cell. Source: (TRCA, 2016).[2].
Visual Indicators Framework - Bioretention/Swales

Component

Indicators

Construction Inspection

Assumption Inspection

Routine Operation Inspection

Verification Inspection
Contributing Drainage Area
CDA condition x x x x
Inlet
Inlet/Flow Spreader Structural Integrity x x x
Inlet/Flow Spreader Structural Integrity x x x x
Pretreatment sediment accumulation x x x
Inlet erosion x x
Perimeter
BMP dimensions x x x
Side slope erosion x x
Surface ponding area x x x
Filter Bed
Standing water x x x
Trash x x
Filter bed erosion x x
Mulch depth x x x x
Filter bed sediment accumulation x x x
Surface ponding depth x x x
Filter bed surface sinking x x x
Check dams x x x x
Planting Area
Vegetation cover x x x x
Vegetation condition x x
Vegetation composition x x x
Outlet
Monitoring well condition x x x x
Sub-drain/Perforated pipe obstruction x x
Overflow outlet obstruction x x x x



The image above shows a manual soil corer, a split soil core sampler kit which preserves the soil sample for further testing (i.e., bulk density) and acrylic core sample tubes. All examples of tools to be use for soil characterization testing. Source: (TRCA, 2016).[3].
Testing Indicators Framework - Bioretention/Swales

Component

Indicators

Construction Inspection

Assumption Inspection

Routine Operation Inspection

Verification Inspection
Testing Indicators
Soil characterization testing x x (x)
Sediment accumulation testing x x x x
Surface infiltration rate testing x (x)
Natural or simulated storm event testing x (x)
Continuous monitoring x (x)
Note: (x) denotes indicators to be used for Performance Verification inspections only (i.e., not for Maintenance Verification inspections)
  1. TRCA. 2016. Fact Sheet - Inspection and Maintenance of Stormwater Best Management Practices: Permeable Pavement. https://sustainabletechnologies.ca/app/uploads/2018/02/Permeable-Pavement-Fact-Sheet.pdf
  2. STEP. 2016. Low Impact Development Stormwater Management Practice Inspection and Maintenance Guide. https://sustainabletechnologies.ca/app/uploads/2016/08/LID-IM-Guide-2016-1.pdf
  3. STEP. 2016. Low Impact Development Stormwater Management Practice Inspection and Maintenance Guide. https://sustainabletechnologies.ca/app/uploads/2016/08/LID-IM-Guide-2016-1.pdf