Changes

Fill from Section 4.0 of the 2016 Guide!!

[[File:The key elements of LID.gif|thumb|600px|A graphic showing the key benefits for effective LID BMP implementation. These elements along with others should be considered during the planning and design phases of LID implementation (Source: Wikimedia Commons, 2012<ref>Wikimedia Commons. 2012. File:The key elements of LID.gif. http://zoe-s-wiki.wikispaces.com/Low+Impact+Development. https://commons.wikimedia.org/wiki/File:The_key_elements_of_LID.gif</ref>).]]

==Overview==

==Overview==

Designing LID BMPs with ease of inspection and maintenance in mind is critical to the affordability of municipal stormwater infrastructure asset management programs and must be considered early on in the overall activity. Generally this occurs during the design and an early stage in the plan review and approval process. The following sections provide tips on tailoring the design of LID BMPs to help reduce the frequency of structural repairs and make inspection and maintenance tasks easier and cheaper to perform by either municipal staff or hired external consultants.

Designing LID BMPs with ease of inspection and maintenance in mind is critical to the affordability of municipal stormwater infrastructure asset management programs and must be considered early on in the overall activity. Generally this occurs during the design and an early stage in the plan review and approval process. The following sections provide tips on tailoring the design of LID BMPs to help reduce the frequency of structural repairs and make inspection and maintenance tasks easier and cheaper to perform by either municipal staff or hired external consultants.

==Provide Runoff Pretreatment==

==Provide Runoff Pretreatment==

[[Pretreatment]] refers to techniques or devices used to retain coarse materials suspended in stormwater runoff, either through filtration or settling, before it enters the BMP rendering it inefficient over time. Proper pretreatment extends the operating phase of the BMP’s life cycle by reducing the rate of accumulation of coarse sediment, thus delaying the need for at times expensive structural repairs like unclogging filter beds, pipes and orifices. Common pretreatment devices include [[vegetated filter strips]], [[grass swales]], [[geotextile]]-lined inlet filters/liners, [[check dams]], [[forebays]], eavestrough screens or filters, [[Oil and grit separators]] (i.e., hydrodynamic separators) and manholes containing baffles, filters and sumps. One important consideration for pretreatment is that these devices require frequent (i.e., at minimal, annual) sediment and trash removal maintenance and should be easy to access by inspection personnel.

[[Pretreatment]] refers to techniques or devices used to retain coarse materials suspended in stormwater runoff, either through filtration or settling, before it enters the BMP rendering it inefficient over time. Proper pretreatment extends the operating phase of the BMP’s life cycle by reducing the rate of accumulation of coarse sediment, thus delaying the need for at times expensive structural repairs like unclogging filter beds, pipes and orifices. Common pretreatment devices include [[vegetated filter strips]], [[Enhanced swales|grass swales]], [[geotextile]]-lined inlet filters/liners, [[check dams]], [[forebays]], eavestrough screens or filters, [[Oil and grit separators| oil and grit separators]] (i.e., hydrodynamic separators) and catch basins or manholes containing baffles, filters and sumps. One important consideration for pretreatment is that these devices require frequent (e.g., annual) sediment and trash removal maintenance and should be easy to access by personnel, vehicles and equipment needed to perform inspection and maintenance tasks.

 

[[File:Oil-grit separator USGS 2002.png|thumb|350px|Example oil-grit separator USGS 2002 (Wikimedia commons)]]

==Design Low Maintenance Conveyance Systems==

==Design Low Maintenance Conveyance Systems==

==Inclusion of Planting Plans==

==Inclusion of Planting Plans==

All vegetated BMP designs should include planting plans that specify [[Plant selection|species]] that can tolerate both wet and dry conditions and, for BMPs that will receive de-icing salt laden runoff during winter, species

All vegetated BMP designs should include planting plans that specify [[Plant selection|species]] that can tolerate both wet and dry conditions and, for BMPs that will receive de-icing salt laden runoff during winter, species

==Inclusion of Sediment Removal Plans==

==Inclusion of Sediment Removal Plans==

As mentioned previously, it is recommended that, where possible, [[pretreatment]] devices be included in BMP designs that help retain coarse sediment and debris in an easily accessible location before it enters the BMP itself. However even with pretreatment devices in place, fine sediment will inevitably reach the BMP and accumulate over time. LID BMP designs need to consider how sediment can be removed from associated manhole sumps, pretreatment devices, inlets and pipes, and include adequate features and routes for access by necessary equipment.  

As mentioned previously, it is recommended that, where possible, [[pretreatment]] devices be included in BMP designs that help retain coarse sediment and debris in an easily accessible location before it enters the BMP itself. However even with pretreatment devices in place, fine sediment will inevitably reach the BMP and accumulate over time. LID BMP designs need to consider how sediment can be removed from associated manhole sumps, pretreatment devices, inlets and pipes, and include adequate features and routes for access by necessary equipment.  

 

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{|class="wikitable" style="width:750px;"

|+'''Sediment Removal Equipment per BMP Type'''

|+'''Sediment Removal Equipment per BMP Type'''

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For underground conveyances (i.e., catchbasins, manholes, [[pipes]]), BMPs, [[pretreatment]] devices, and in-line [[Media filters|filters]], sediment removal often requires crews performing the work to enter confined spaces. Contractors or staff performing the work must have confined space entry training to satisfy occupational health and safety requirements ([https://www.ontario.ca/laws/regulation/050632#:~:text=(1)%20Every%20worker%20who%20enters,632%2F05%2C%20s. Ont. Reg. 632/05 – Confined Spaces Regulation]). <br>

For underground conveyances (i.e., catchbasins, manholes, [[pipes]]), BMPs, [[pretreatment]] devices, and in-line [[Media filters|filters]], sediment removal often requires crews performing the work to enter confined spaces. Contractors or staff performing the work must have confined space entry training to satisfy occupational health and safety requirements ([https://www.ontario.ca/laws/regulation/050632#:~:text=(1)%20Every%20worker%20who%20enters,632%2F05%2C%20s. Ont. Reg. 632/05 – Confined Spaces Regulation]). <br>

How the material removed from conveyances, LID BMPs, [[pretreatment]] devices and in-line filters will be safely and sustainably managed also needs consideration. Due to the small drainage area of most LID BMPs, the rate at which they accumulate sediment and associated contaminants tends to be low in comparison to centralized stormwater treatment facilities like [[SWM ponds|stormwater ponds]] or detention chambers/tanks that receive drainage from much larger areas. As a result, the potential for sediment accumulated in LID BMPs to qualify as contaminated according to [https://www.ontario.ca/page/soil-ground-water-and-sediment-standards-use-under-part-xv1-environmental-protection-act Ontario Brownfields Regulation 153/04 standards for soil and sediment (OMOE, 2011)] is low. <br>

How the material removed from conveyances, LID BMPs, [[pretreatment]] devices and in-line filters will be safely and sustainably managed also needs consideration. Due to the small drainage area of most LID BMPs, the rate at which they accumulate sediment and associated contaminants tends to be low in comparison to centralized stormwater treatment facilities like [[SWM ponds|stormwater ponds]] or detention chambers/tanks that receive drainage from much larger areas. As a result, the potential for sediment accumulated in LID BMPs to qualify as contaminated according to [https://www.ontario.ca/page/soil-ground-water-and-sediment-standards-use-under-part-xv1-environmental-protection-act Ontario Brownfields Regulation 153/04 standards for soil and sediment (Ministry of the Environment, 2011)<ref>Ministry of the Environment. 2011. Soil, ground water and sediment standards for use under Part XV.1 of the Environmental Protection Act. This document provides Ontario’s soil, ground water and sediment standards effective July 1, 2011. PIBS # 7382e01. https://www.ontario.ca/page/soil-ground-water-and-sediment-standards-use-under-part-xv1-environmental-protection-act</ref>] is low. <br>

Most often, contractors or staff performing sediment removal maintenance procedures will be cleaning multiple BMPs and pretreatment devices at multiple sites on any given day. At the end of the day, the mixture of material collected either manually, or by vacuum equipment (e.g., regenerative air or vacuum sweeper, vacuum/soil blower truck, hydro-vac truck) will include a mixture of re-usable, recyclable and non-recyclable constituents. In order to recover reusable and recyclable materials and minimize the volume of material needing to be managed otherwise, the mixture should be screened to isolate trash (for recycling or disposal), natural debris and [[mulch]] (for composting), and [[gravel]] - to pebble-sized [[aggregates]] (for washing and re-use) from finer (i.e., [[sand]] - to [[Texture|clay-sized]]) material. The sand- to clay-sized material (i.e., material passing a 2 mm diameter ([https://www.endecotts.com/faq/sieves-and-calibration/american-standard-test-sieve-series-astm/ ASTM No. 10]) sieve) should then be assessed and managed in accordance with [https://www.ontario.ca/laws/regulation/900347 provincial regulations (O.Reg. 347)].

Most often, contractors or staff performing sediment removal maintenance procedures will be cleaning multiple BMPs and pretreatment devices at multiple sites on any given day. At the end of the day, the mixture of material collected either manually, or by vacuum equipment (e.g., regenerative air or vacuum sweeper, vacuum/soil blower truck, hydro-vac truck) will include a mixture of re-usable, recyclable and non-recyclable constituents. In order to recover reusable and recyclable materials and minimize the volume of material needing to be managed otherwise, the mixture should be screened to isolate trash (for recycling or disposal), natural debris and [[mulch]] (for composting), and [[gravel]] - to pebble-sized [[aggregates]] (for washing and re-use) from finer (i.e., [[sand]] - to [[Texture|clay-sized]]) material. The sand- to clay-sized material (i.e., material passing a 2 mm diameter ([https://www.endecotts.com/faq/sieves-and-calibration/american-standard-test-sieve-series-astm/ ASTM No. 10]) sieve) should then be assessed and managed in accordance with [https://www.ontario.ca/laws/regulation/900347 provincial regulations (O.Reg. 347)].