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*For [[Absorbent landscapes|soil amendment areas]], inspection involves confirming that topsoil depth and degree of compaction are acceptable in the specified areas;
*For [[Absorbent landscapes|soil amendment areas]], inspection involves confirming that topsoil depth and degree of compaction are acceptable in the specified areas;
*Check for side slope erosion/damage from vehicular/foot traffic.
*Check for side slope erosion/damage from vehicular/foot traffic.
|[[File:Perimeter Pass swale.PNG|315px|thumb|center|The footprint area of the BMP does not significantly deviate from the final design and should not negatively affect its stormwater management treatment performance.]]  
|[[File:Perimeter grass pass.JPG|315px|thumb|center|The footprint area where soil amendments have been implemented does not significantly deviate from the final design and should not negatively affect its stormwater management treatment performance.]]  
|[[File:Perimeter Fail swale.PNG|310px|thumb|center|The footprint area of the BMP is significantly smaller than what was specified in the final design of this example and differ greater than the recommended SWM criteria requirements (>10%), due to half the width having been paved over.]]  
|[[File:Perimeter grass fail.JPG|310px|thumb|center|The footprint area where soil amendments have been implemented is significantly smaller than what was specified in the final design.]]  
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|'''[[Filter strips: Performance|Filter Bed]]'''
|'''[[Filter strips: Performance|Filter Bed]]'''
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*Re-grade and restore cover over any animal burrows, sunken areas when ≥ 10 cm in depth and erosion rills when ≥ 30 cm in length;
*Re-grade and restore cover over any animal burrows, sunken areas when ≥ 10 cm in depth and erosion rills when ≥ 30 cm in length;
*Add stone cover to maintain 5 to 10 cm depth where specified in the planting plan
*Add stone cover to maintain 5 to 10 cm depth where specified in the planting plan
|[[File:Filter Bed Pass swale.PNG|315px|thumb|center|The filter bed has retained its original grading without any sharp depressions that would indicate surface bed sinking.]]
|[[File:Filter bed grass pass.png|315px|thumb|center|There are no erosion rills, gullies or bare soil areas on the filter strip surface. (Photo Source: Washington State Department of Transportation, 2018)<ref>Washington State Department of Transportation. 2018. Vegetated Filter Strips: Low-impact development fact sheet. Authored by: Maria Cahill, Derek Godwin, and Jenna Tilt. Published June 2018. Accessed: 14 July 2022. https://catalog.extension.oregonstate.edu/em9208/html</ref>]]
[[File:Surface ponding Pass Swale.PNG|315px|thumb|center|TThe maximum surface ponding depth behind check dams matches what was specified in the final design. (Source:
|[[File:Filter bed grass fail.JPG|300px|thumb|center|Scour erosion along the inlet edge is visible. Bare soil areas and bright green biofilm on the filter strip surface indicate that concentrated flow and surface ponding occurs regularly.]]  
Mark M. Holeman, Inc., 2015)<ref>Mark M. Holeman, Inc. 2015. What is a Bio-Swale? Authored by Rick Blankenship. 25 September 2015. Accessed 5 July 2022. http://www.holemanlandscape.com/2015/09/25/what-is-a-bio-swale/</ref>]]
[[File:Filter bed depression grass fail.JPG|300px|thumb|center|Clear evidence of bed sinking on the lawn, creating preferential ponding areas which could cause vegetation to die off (Source: The Anxious Gardener<ref>The Anxious Gardner. n.d. Gallery. Accessed 14 July 2022. https://theanxiousgardener.com/</ref>)]].
|[[File:Filter Bed Fail swale.PNG|300px|thumb|center|Clear evidence of bed sinking is visible, creating a preferential ponding area where vegetation has died off.]]  
[[File:Surface ponding Fail Swale.PNG|300px|thumb|center|The maximum ponding depth of the swale is significantly deeper than intended as the elevation of the check dam or overflow outlet is too high. (Source: Stiffler, 2012<ref>Stiffler, L. 2012.RAIN GARDEN REALITY CHECK: Comparing LID to conventional system failures. Authored by: Eric De Place. 18 April 2012. Sightline Institute. Sustainable Living Series. Accessed 5 July 2022. https://www.sightline.org/2012/04/18/rain-garden-reality-check/</ref>)]]
|-
|-
|'''[[Vegetation]]'''
|'''[[Vegetation]]'''
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*Cut back spent plants
*Cut back spent plants
*Divide or thin out overcrowded plants
*Divide or thin out overcrowded plants
|[[File:Veg Cover Pass swale.PNG|315px|thumb|center|The planted portion of the swale is well covered with dense, attractive vegetation which helps to maintain its stormwater treatment function and aesthetic value.]]  
|[[File:Vegetation grass pass.JPG|315px|thumb|center|The vegetated filter strip is evenly covered with dense turf grass which helps to maintain its stormwater treatment function and aesthetic value. (Photo Source: Trinkaus Engineering))]]  
|[[File:Veg Cover Fail swale.PNG|315px|thumb|center|Major portions of the swale surface contains dead or dying vegetation which reduces its aesthetic value and could be negatively affecting its stormwater treatment function.]]  
|[[File:Vegetation grass fail.JPG|315px|thumb|center| Major portions of the filter strip contain bare soil or dead vegetation which reduces its aesthetic value and could be negatively affecting its stormwater treatment function]]  
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==Tips to Preserve Basic BMP Function==
*Because the risk of compaction is higher when topsoil is saturated, any maintenance tasks involving vehicle (e.g., ride mower) or foot traffic on the filter bed should not be performed during wet weather.
*Use push mower to maintain enhanced swales with [[grasses]] as [[vegetation]] cover or the lightest ride mower equipment available to minimize compaction of the filter bed.
*Use a mulching mower to maintain enhanced swales with grass as vegetation cover or leave clippings on the surface to help replenish organic matter and nutrients in the topsoil.
*Pruning of mature [[trees]] should be performed under the guidance of a Certified Arborist.
*Woody vegetation should not be planted or allowed to become established where snow will be piled/stored during winter.
*Removal of sediment accumulated on the filter bed surface should be performed by hand with rake and shovel, or vacuum equipment where feasible. If a small excavator is the chosen method, keep the excavator off the BMP footprint to avoid damage to side slopes/embankments and compaction of the [[topsoil]].
==Rehabilitation & Repair==
Table below provides guidance on rehabilitation and repair work specific to vegetated/grass filter strips and soil amendments organized according to BMP component.
[[File:Levelspread.jpg|thumb|440px|This clever design incorporates a level spreading device after a [[curb cut]] has narrowed the flow path. This kind of treatment train approach would provide an opportunity to provide [[pretreatment]] at the point of concentration. This repair helps to limit the potential of erosion occurring within the feature. Photo credit: [https://www.pca.state.mn.us/featured/when-it-rains-it-flows (MPCA, 204)]<ref>Minnesota Pollution Control Agency. 2014. When it rains, it flows. 6 May 2014. Accessed 156 July 2022. https://www.pca.state.mn.us/featured/when-it-rains-it-flows</ref>]] 
{|{| class="wikitable" style="width:900px;"
|+'''Vegetated Filter Strips and Soil Amendments Key Components, Typical Issues and Rehabilitation Requirements'''
|-
!Component
!Problem
!Rehabilitation Tasks
|-
|'''[[Inlets]]'''
|
Inlet or flow spreading device is producing concentrated flow and causing filter bed erosion.
|
*Add [[Level spreaders|flow spreading device]] or re-grade existing device back to level to promote sheet flow to the filter bed. Regrade damaged portion of the filter bed and replant. If problem persists, consider adding [[turf grasses|turf]] reinforcement devices or replace filter bed [[vegetation]] cover with stone at inlets.
|-
|rowspan="7"|'''[[Vegetated filter strips#Design|Filter Bed]]'''
|Topsoil is overly compacted.
|
*Core aerate; or remove [[stone]], [[mulch]] and [[vegetation]] cover and till topsoil to a depth of 20 cm; or remove and replace with uncompacted topsoil that meets design specifications. Replace stone, mulch and vegetation cover (reuse/transplant where possible).
|-
|[[Topsoil]] organic matter or [[phosphorus]] content too low and [[vegetation]] not thriving.
|
*Top dress with [[compost]]
|-
|[[Topsoil]] [[pH]] is out of specification range (6.0 to 7.8) and [[vegetation]] not thriving.
|
*If soil [[pH]] is lower than 6.0, amend with ground [[Phosphorus testing in media|limestone]] to raise the pH back to neutrality. If soil pH is higher than 7.8, amend with [[compost]] or [[Test pit|sulphur]] to lower the pH back to neutrality.
|-
|Topsoil [[soluble salts]] content exceeds 2.0 mS/cm .
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*Flush affected area with fresh water.
|-
|Surface ponding remains for > 24 hours or surface infiltration rate is out of acceptable range.
|
*Remove any [[Clogging|accumulated sediment]] and core aerate. If problem persists, remove [[vegetation]], till the [[topsoil]] to a depth of 20 cm to reduce compaction, or remove and replace the uppermost 15 cm of material with topsoil that meets design specifications. Replace [[vegetation]] cover (transplant where possible).
|-
|Damage to filter bed is present (e.g., erosion rills, animal burrows, local sinking, ruts)
|
*Re-grade damaged portion and restore [[vegetation]] cover. Animal burrows, local sinking and compacted areas should be tilled to 20 cm depth prior to re-grading and planting.
|-
|}
==Inspection Time Commitments and Costs==
Estimates of the life cycle costs of inspection and maintenance have been produced using the latest version of the [[Cost analysis resources|LID Life Cycle Costing Tool]] (LCCT) to assist stormwater infrastructure planners, designers and asset managers with planning and preparing budgets. <br>
For [[vegetated filter strips]] and [[Absorbent landscapes|soil amendment areas]], life cycle cost estimates have been calculated for two level-of-service scenarios: the minimum recommended frequency of inspection and maintenance tasks , and a high frequency scenario to provide an indication of the potential range. The LCCT has assumptions for [[vegetated filter strips]] and [[Absorbent landscapes|soil amendment areas]] based on an impervious to pervious area (I:P) ratio of 2.5:1 and inspection and maintenance recommendations for enhanced swales, for relevant components.
</br>
[[File:Veg filter LCCT.JPG|thumb|center|1000px|The life cycle cost estimates for vegetated filter strips and soil amendments are presented in the above table. No design variations scenarios were examined, therefore the Minimum Recommended and High Frequency maintenance scenarios  are the only two scenarios examined for this BMP. It is assumed that no rehabilitation work will be needed to maintain acceptable drainage performance over a 50 year time period (TRCA, 2016)<ref>Toronto and Region Conservation Authority (TRCA). 2016. Low Impact Development Stormwater Management Practice Inspection and Maintenance Guide. Prepared by the Sustainable Technologies Evaluation Program. Vaughan, Ontario. https://sustainabletechnologies.ca/app/uploads/2016/08/LID-IM-Guide-2016-1.pdf</ref>]]<br>
</br>
Assumptions for the above costs are based on the following:
*The annual average maintenance cost represents an average of routine maintenance tasks, as outlined above in [[Inspection and Maintenance: Vegetated Filter Strips#Routine Maintenance - Key Components and I&M Tasks|Routine Maintenance - Key Components and I&M Tasks]] All cost value estimates represent the NPV as the calculation takes into account average annual interest (2%) and discount (3%) rates over the evaluation time periods.
*The CDA has been defined as 2,000 m<sup>2</sup> of impermeable pavement (e.g., road or parking area) which drains by sheet flow to a vegetated filter strip that is approximately 800 m<sup>2</sup> in area (I:P ratio of 2.5:1), 70 m long, 11.4 m wide and situated along the long edge of the paved area. The side slope is defined as 12.5:1 (8%). Water enters the BMP as sheet flow from a gravel diaphragm flow spreading device along the edge adjacent to the pavement. The BMP surface is planted with grass and does not include check dams, nor any pipes or culverts.
*Estimates of the life cycle costs of vegetated filter strips and soil amendment areas in Canadian dollars per unit CDA ($/m<sup>2</sup>) are presented above. The [[Cost analysis resources|LCCT) allows users to select what BMP type and design variation applies, and to use the default assumptions to generate planning level cost estimates. Users can also input their own values relating to a site or area, design, unit costs, and inspection and maintenance task frequencies to generate customized cost estimates, specific to a certain project, context or stormwater infrastructure program. <br>
</br>
'''Notes:'''
<small>
#Estimated life cycle costs represent NPV of associated costs in Canadian dollars per square metre of CDA ($/m<sup>2</sup>).
#Average annual maintenance cost estimates represent NPV of all costs incurred over the time period and do not include rehabilitation costs.
#Rehabilitation cost estimates represent NPV of all costs related to repair work assumed to occur every 25 years including those associated with inspection and maintenance over a two (2) year establishment period for the plantings.
#Life cycle costs are very similar but slightly lower for BMPs constructed with filter sock or rock check dams, than concrete ones due to differences in material and labor unit costs.
#Rehabilitation costs are estimated to be between 24.4 to 28.1% of the original construction costs for High Frequency and Minimum Recommended maintenance program scenarios, respectively.
#It is assumed that no rehabilitation is needed to maintain acceptable drainage performance over a 50 year evaluation period.
#Maintenance and rehabilitation costs over a 25 year time period are estimated to be 3.52 to 5.42 times the original construction cost, for the Minimum Recommended and High Frequency maintenance scenarios respectively.
#Maintenance and rehabilitation costs over a 50 year time period are estimated to be 6.16 and 9.57 times  the original construction cost for the Minimum Recommended and High Frequency maintenance scenarios respectively.</small>
==Inspection Field Data Sheet==
Feel free to '''download''' (downward facing arrow on the top righthand side) and '''print''' (Pinter emoticon on top right hand side) the following [[Vegetated filter strips]] and [[Absorbent landscapes|Soil amendments]] Inspection Field Data Form developed by TRCA, STEP and its partners for the [https://sustainabletechnologies.ca/app/uploads/2016/08/LID-IM-Guide-2016-1.pdf Low Impact Development Stormwater Management Practice Inspection and Maintenance Guide]<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>.
The 6 page document prompts users to fill out details previously mentioned above on this page in other sections about various zones associated with [[[Vegetated Filter strips]] and [[Absorbent landscapes|Soil amendments]]  features (i.e. inlets, perimeter of the feature, filter bed, outlets, etc.) and describe why each area is a pass or fail, and if remediate action is required and under what timeframe it would be completed by. Furthermore, the forms prompt the reviewer to determine what type of inspection is being conducted for the feature in question: Construction (C), Routine Operation (RO), Maintenance Verification (MV), or Performance Verification (PV). <br>
<br>
[[File:Filterstrip toronto 2021.JPG|thumb|340px|Example of a plan drawing and appropriate construction specifications for [[Vegetated filter strips]] designed and implemented within Toronto's, municipal bounds (City of Toronto, 2021)<ref>City of Toronto. 2021. Construction Specifications and Drawings for Green Infrastructure. T-850.151 Vegetated Filter Strip – Section. Developed by: Engineering and Construction Services. https://www.toronto.ca/wp-content/uploads/2021/08/9646-ecs-specs-gi-dwgs-T-850.151-Rev0-Sep2021.pdf</ref>]]
<pdf width="900" height="800">File:Fitler strips inspection sheet.pdf</pdf>
==References==

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