Changes

Regular inspections (twice annually, at a minimum) done as part of routine maintenance tasks over the operating phase of the BMP life cycle to determine if maintenance task frequencies are adequate and determine when rehabilitation or further investigations into BMP function are warranted.

Regular inspections (twice annually, at a minimum) done as part of routine maintenance tasks over the operating phase of the BMP life cycle to determine if maintenance task frequencies are adequate and determine when rehabilitation or further investigations into BMP function are warranted.

Table below describes routine maintenance tasks for [[bioretention]] practices, organized by BMP component, along with recommended minimum frequencies. It also suggests higher frequencies for certain tasks that may be warranted for BMPs located in highly visible locations or those receiving flow from high traffic areas (vehicle or pedestrian). Tasks involving removal of trash, debris and sediment and weeding/trimming of [[vegetation]] for BMPs in such contexts may need to be done more frequently (i.e., higher standards may be warranted).

Table below describes routine maintenance tasks for [[permeable pavements]], organized by BMP component, along with recommended minimum frequencies. It also suggests higher frequencies for certain tasks that may be warranted for BMPs located in highly visible locations or those receiving flow from high traffic (vehicle or pedestrian) areas or those designed with higher than recommended impermeable drainage area to permeable BMP footprint area ratios ([[Notation|I:P ratios]]). Tasks involving removal of trash, debris and sediment and weeding/trimming of vegetation for BMPs in such contexts may need to be done more frequently (i.e., higher standards may be warranted).  

Individuals conducting [[vegetation]] maintenance and in particular, weeding (i.e., removal of undesirable vegetation), should be familiar with the species of [[Plant lists|plants]] specified in the planting plan and experienced in plant identification and methods of removing/controlling noxious weeds. Key resources on these topics are provided below at the links provided:

Individuals conducting [[vegetation]] maintenance and in particular, weeding (i.e., removal of undesirable vegetation), should be familiar with the species of [[Plant lists|plants]] specified in the planting plan and experienced in plant identification and methods of removing/controlling noxious weeds. Key resources on these topics are provided below at the links provided:

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|+'''Bioretention/Swales: Key Components, Descriptions and Routine I&M Requirements'''

|+'''Permeable Pavements: Key Components, Descriptions and Routine I&M Requirements'''

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!style="width: 500px"|Comnponent  

!style="width: 500px"|Comnponent  

!style="width: 550px"|<span style="color:red">('''Fail''')</span> Photo Example

!style="width: 550px"|<span style="color:red">('''Fail''')</span> Photo Example

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|'''[[Bioretention: Sizing|Contributing Drainage Area (CDA)]]'''

|'''[[Permeable pavements: Sizing|Contributing Drainage Area (CDA)]]'''

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Area(s) from which runoff directed to the BMP originates; includes both impervious and pervious areas.  

Area(s) from which runoff directed to the BMP originates; includes the pavement itself and any adjacent impermeable pavement or roofs that drain to it.

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*Remove trash, debris and sediment from pavements (biannually to quarterly) and eavestroughs (annually);

*Remove trash, debris and sediment from pavements (biannually to quarterly) and eavestroughs (annually);

*Remove trash, debris and sediment annually to biannually or when the device sump is half full;

*Remove trash, debris and sediment annually to biannually or when the device sump is half full;

*Measure sediment depth or volume during each cleaning, or annually to estimate accumulation rate and optimize frequency of maintenance

*Measure sediment depth or volume during each cleaning, or annually to estimate accumulation rate and optimize frequency of maintenance

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|'''[[Inlets]]'''

|'''[[Inlets]]'''

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Structures that deliver water to the BMP (e.g., [[Curb cuts]], [[inlets|spillways]], pavement edges, [[inlets|catch basins]], [[pipes]]).

Structures that deliver water to the BMP (e.g., impermeable pavement edges, [[pipes]] from roof downspouts or catchbasins).

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*Keep free of obstructions;

*Keep free of obstructions;

*Remove trash, debris and sediment biannually to quarterly;

*Remove trash, debris and sediment biannually to quarterly;

*Measure sediment depth or volume during each cleaning or annually to estimate accumulation rate and optimize frequency of maintenance;

*Make note of sediment depth or volume during each cleaning or annually to estimate accumulation rate and optimize frequency of maintenance

|[[File:Inlets bio pass.PNG|285px|thumb|center|There is no evidence of damage or displacement of the inlet structure that would prevent runoff from freely entering the BMP.]]  

|[[File:Inlets bio pass.PNG|285px|thumb|center|There is no evidence of damage or displacement of the inlet structure that would prevent runoff from freely entering the BMP.]]  

|[[File:Inlets bio fail.PNG|300px|thumb|center|Accumulated sediment and vegetation is preventing stormwater from entering the BMP. Sediment on the pavement surface in front of the inlet indicates ponding is also occurring]]  

|[[File:Inlets bio fail.PNG|300px|thumb|center|Accumulated sediment and vegetation is preventing stormwater from entering the BMP. Sediment on the pavement surface in front of the inlet indicates ponding is also occurring]]  

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|'''Perimeter'''

'''[[Permeable pavements: Specifications|Pavement Surface]]'''

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Side slopes or structures that define the BMP footprint; may be covered by a mixture of [[vegetation]], [[mulch]] and [[stone]] with slopes up to 2:1 (H:V), or concrete or masonry structures with vertical walls.

The surface of the pavement, including pavers/pavement, joints and edge restraints (e.g., curbs, edging); should not allow water to pond on the surface so any observation or evidence of surface ponding (e.g., sediment caking on the pavement) indicates a drainage problem.

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*Check for sediment, surface ponding, deformation, sink holes, damage and loss of joint fill;

*Check for side slope erosion or damage that compromises water storage capacity

*Remove trash regularly (biannually-quarterly);

*Grid systems with soil and grass fill are maintained like lawns;

*Sweep and vacuum interlocking and rigid pavements regularly (annually-biannually) with regenerative air/pure vacuum sweeper;

*Plow snow as needed and spread deicers sparingly during winter;

*Repair ruts or local sinking of 15 mm or greater over a 3 metre length, adjacent pavers or cracks in pervious concrete or porous asphalt are vertically offset by 5 mm or greater and paver joint fill is missing or below 15 mm from the paver surface.

Flat or gently sloping area composed of a 0.5 to 1 m deep layer of [[filter media]] soil covered by a mixture of [[vegetation]], [[mulch]] and [[stone]] where [[Bioretention: TTT|surface ponding]] and filtration of runoff occurs.

*Check for standing water, barren/eroded areas, sinkholes or animal burrows;

*Remove trash biannually to quarterly;

*Rake regularly to redistribute [[mulch]] and prevent sediment crusts;

*Maintain 5 to 10 cm of mulch or stone cover to prevent weed growth and soil [[erosion]];

*Repair sunken areas when ≥ 10 cm deep and barren/eroded areas when ≥ 30 cm long;

*Remove sediment when > 5 cm deep or time to drain water ponded on the surface exceeds 48 hours.

|[[File:Filter bed bio pass.PNG|295px|thumb|center|There are no erosion gullies or bare soil areas on the filter bed surface and mulch cover remains in place.]]

|[[File:Filter bed bio fail.PNG|300px|thumb|center|Erosion gullies and bare soil areas are present on the filter bed surface, indicating that concentrated flow occurs regularly into the BMP feature. (Photo Source: CVC).]]

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|'''[[Vegetation]]'''

|'''[[Vegetation]]'''

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A mixture of deep rooting perennial plants, tolerant to both wet and dry conditions and salt (if receiving pavement runoff); can include grasses, flowers, shrubs and trees; roots uptake water and return it to the atmosphere; provide habitat for organisms that break down trapped pollutants and help maintain soil structure and permeability.

Applies to grid paver systems only; a mixture of deep rooting perennial grasses or low growing ground covers, tolerant to both wet and dry conditions and salt (if receiving impermeable pavement runoff); roots uptake water and return it to the atmosphere, provide habitat for soil organisms that break down pollutants trapped in the soil and help maintain soil structure and permeability.

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*Routine maintenance is the same as a conventional perennial garden bed;

*Grid systems with soil and grass fill are maintained like lawns;

*In the first 2 months water plantings frequently (biweekly in the absence or rain) and as needed (e.g., bimonthly) over the remainder of the first growing season;

*In the first 2 months water frequently (biweekly in the absence or rain) and as needed (e.g., bimonthly) over the remainder of the first growing season;

*Remove weeds and undesirable plants biannually to quarterly;

*Remove weeds and undesirable plants biannually to quarterly;

*Replace dead plantings annually to achieve 80% cover by the third growing season;

*Replace/reseed dead plantings annually to achieve 80% cover by the third growing season;

*Do not apply chemical fertilizers.  

*Do not apply chemical fertilizers.

|[[File:Vegetation bio pass.PNG|315px|thumb|center|The planted portion of the bioretention cell is completely covered with dense, attractive vegetation which helps to maintain its stormwater treatment function and aesthetic value.]]  

|[[File:Vegetation bio pass.PNG|315px|thumb|center|The planted portion of the bioretention cell is completely covered with dense, attractive vegetation which helps to maintain its stormwater treatment function and aesthetic value.]]  

|[[File:Vegetation bio fail .PNG|290px|thumb|center|A larger portion of the bioretention cell has no vegetation cover which reduces its aesthetic value and could be negatively affecting its stormwater treatment function. Much less than 80% of the planting area is covered by living vegetation requiring immediate maintenance and reseeding.]]  

|[[File:Vegetation bio fail .PNG|290px|thumb|center|A larger portion of the bioretention cell has no vegetation cover which reduces its aesthetic value and could be negatively affecting its stormwater treatment function. Much less than 80% of the planting area is covered by living vegetation requiring immediate maintenance and reseeding.]]  

|'''[[Overflow|Overflow Outlet]]'''

|'''[[Overflow|Overflow Outlet]]'''

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Structures that convey overflows to another BMP or municipal storm sewer.

Structures (e.g., catchbasin, curb-cut, [[swale]]) that convey flow that exceeds the storage capacity of the BMP to another drainage system (e.g., municipal storm sewer or other BMP).  

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*Keep free of obstructions;

*Keep free of obstructions;

|'''[[Underdrain|Sub-drain]]'''

|'''[[Underdrain|Sub-drain]]'''

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Optional component; [[Pipes|perforated pipe(s)]] surrounded by [[gravel]] and may be wrapped in [[Geotextile|geotextile filter fabric]]; installed below the [[filter media]] soil layer to collect and convey treated water to an adjacent drainage system; may also include a flow restrictor.  

Optional component; [[Pipes|perforated pipe(s)]] surrounded by [[gravel]] and may be wrapped in [[Geotextile|geotextile filter fabric]]; installed in the base or sub-base gravel layer to collect and convey treated water to an adjacent drainage system or other BMP; may also include a flow restrictor.

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*Keep pipe and flow restrictor free of obstructions by flushing annually;

*Keep pipe and flow restrictor free of obstructions by flushing annually;

*Inspect flow restrictor frequently (e.g., biannually to quarterly).

*Inspect flow restrictor regularly (e.g., biannually to quarterly).

|[[File:Underdrain bio pass.PNG|310px|thumb|center|The perforated sub-drain pipe is not obstructed by sediment, debris or roots and shows no signs of damage.]]  

|[[File:Underdrain bio pass.PNG|310px|thumb|center|The perforated sub-drain pipe is not obstructed by sediment, debris or roots and shows no signs of damage.]]  

|[[File:Underdrain bio fail.PNG|300px|thumb|center|Roots have penetrated the underdrain/sub-drain pipe and are substantially reducing its conveyance capacity. Structural damage, sediment/debris clogs or vegetation roots are visible and are reducing the conveyance capacity of the pipe by one third (33%) or more. (Photo Source: Pipelining Denver)]]  

|[[File:Underdrain bio fail.PNG|300px|thumb|center|Roots have penetrated the underdrain/sub-drain pipe and are substantially reducing its conveyance capacity. Structural damage, sediment/debris clogs or vegetation roots are visible and are reducing the conveyance capacity of the pipe by one third (33%) or more. (Photo Source: Pipelining Denver)]]  

|'''[[Monitoring well]]'''

|'''[[Monitoring well]]'''

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[[Wells|Perforated standpipe]] that extends from the bottom of the BMP to above the invert of the [[Overflow|overflow outlet]]. Allows [[Digital technologies|measurement of subsurface water level]] to track drainage performance over time.

[[Wells|Perforated standpipe]] that extends from the bottom of the excavation to just below the pavement surface and contains perforations or slots to allow [[Digital technologies|measurement of subsurface water level]]; used to track drainage performance over the operating life cycle of the BMP.

Manhole or catchbasin to which the subdrain outlets that provides access to the [[underdrain]] and flow restrictor. Inspect for accessibility, damage and sediment.

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*[[Wells|Standpipes]] should be securely capped on both ends and remain undamaged.

*Remove trash, debris and sediment regularly (biannually/quarterly)..

|[[File:MonitoringWell bio pass.PNG|340px|thumb|center|The well is undamaged and accessible and the cap is in place and secured to prevent unauthorized access.]]  

|[[File:MonitoringWell bio pass.PNG|340px|thumb|center|The well is undamaged and accessible and the cap is in place and secured to prevent unauthorized access.]]  

|[[File:MonitoringWell bio fail.PNG|300px|thumb|center|The well standpipe has been damaged by snow plowing, which impairs its use for monitoring and is a safety hazard. With the cap unable to be secured unauthorized access can also occur.]]  

|[[File:MonitoringWell bio fail.PNG|300px|thumb|center|The well standpipe has been damaged by snow plowing, which impairs its use for monitoring and is a safety hazard. With the cap unable to be secured unauthorized access can also occur.]]  

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