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→Sediment controls
===Sediment controls===
===Sediment controls===
{| class="wikitable sortable" style="width:100%; text-align:left;"
{| class="wikitable" style="width:100%; text-align:left;"
|+ '''Table 2. Sediment Controls'''
|+Table 2. Sediment Controls
! Practice (click for detailed design requirements – opens appendix PDF)
! Practice (click for detailed design requirements – opens appendix PDF)
! Description
! Description
| Sediment Control Fence
| Sediment Control Fence
| Geotextile material supported by posts and trenched into the ground to support settling of sheet flows.
| Geotextile material supported by posts and trenched into the ground to support settling of sheet flows.
| Site perimeters, up-gradient sides of sensitive areas or streams, around material stockpiles, and parallel to sediment-laden sheet flows.
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*Site perimeter
*up-gradient side of sensitive areas/streams
*Around material stockpiles
*1.5 m away from slope base
*Do not install perpendicular to concentrated flows
*Parallel to areas with sediment laden sheet flow
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| Filter Socks
| Filter Socks
| Tubular mesh socks filled with wood chip or compost that dissipate flow velocities and pond water to promote sediment settling.
| Tubular mesh socks filled with wood chip or compost that dissipate flow velocities and pond water to promote sediment settling.
| Along contours on level or sloped areas, site perimeters, slope bases, as check dams, or around storm drains and stockpiles.
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*applied along contours on level and sloped areas, perpendicular to sheet flows
*1.5 m from slope base
*site perimeter
*as check dams in swales and ditches
*around storm drain inlets and sediment bags
*base of topsoil stockpiles
*in place of sediment fence when frozen
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| Natural Fibre Logs
| Natural Fibre Logs
| Similar to filter socks but made of biodegradable materials such as coir, straw, or wood.
| Similar to filter socks but made of biodegradable materials such as coir, straw, or wood.
| Along contours, at slope bases, perimeters, as check dams, or around storm drains and stockpiles.
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*applied along contours on level and sloped areas, perpendicular to sheet flows
*1.5 m from slope base
*site perimeter
*as check dams in swales and ditches
*Around storm drain inlets and sediment bags
*base of topsoil stockpiles
*in place of sediment fence when frozen
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| Rock Check Dams
| Rock Check Dams
| Weir constructed across channels from granular material and geotextile to reduce flow velocity.
| Weir constructed across channels from granular material and geotextile to reduce flow velocity.
| Perpendicular to concentrated flow paths in long or steep channels; not for natural features.
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*Perpendicular to concentrated flow channels, especially in long/steep channels
*Do not use in natural features
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| Vehicle Tracking Controls
| Vehicle Tracking Controls
| Measures such as mud mats, shaker racks, or wheel washers to prevent vehicles from tracking mud offsite.
| Measures such as mud mats, shaker racks, or wheel washers to prevent vehicles from tracking mud offsite.
| Construction site entrances and exits where soil tracking is likely due to grading, weather, or heavy equipment.
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Vehicle tracking controls:
*site >1 ha
*grading/filling close to entrances
*Weather/site conditions cause mud
Wheel washing:
*Mud tracking ongoing issue and vehicle tracking controls not providing mitigation/cannot be constructed due to site constraints
*contaminated soils
*required by municipality
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| Sediment Dewatering Bags
| Sediment Dewatering Bags
| Large geotextile bags used to filter sediment-laden water from pumped discharge.
| Large geotextile bags used to filter sediment-laden water from pumped discharge.
| Dewatering operations requiring space-efficient sediment removal.
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*anywhere dewatering necessary to create a dry work area, particularly where space limited
*where flow dispersion is needed to prevent erosion
*best used in treatment train
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| Storm Drain Inlet Protection
| Storm Drain Inlet Protection
| Temporary barrier to block sediment entry to inlets while allowing water through.
| Blocks sediment entry to inlets while allowing water through.
| Around or overtop inlets at grade or within storm drains; used for areas draining ≤1 ha.
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*all operational inlets at grade around or overtop the inlet
*below grade inside a storm drain
*treatment train required for drainage areas >1 ha
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| Sediment Traps
| Sediment Traps
| Runoff detention area created by an embankment or depression to allow sediment settling.
| Runoff detention area created by an embankment or depression to allow sediment settling.
| At the end of treatment trains or across small drainage features (≤2 ha).
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*end of a treatment train before discharged offsite
*across drainage/conveyance features
*drainage areas ≤ 2 ha that do not drain to another detention feature
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| Sediment Ponds
| Sediment Ponds
| Larger, excavated depressions that provide temporary or permanent sediment storage and water retention.
| Similar to sediment traps but larger. Excavated depression for [[Wet ponds|permanent water retention]]
| End-of-pipe control for drainage areas >2 ha.
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*Treatment of runoff from drainage areas > 2 ha
*end-of-pipe control
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| Weir Tanks
| Weir Tanks
| Tanks that detain stormwater runoff to promote sediment settling.
| Tanks that detain stormwater runoff to promote sediment settling.
| Used for short-term pumping or dewatering where high sediment removal or large capacity is required.
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*Sediment removal for short-term pumping / dewatering activities
*when more stringent effluent water quality standards required
*Planned pumping rates are high and require large capacity
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| Polymer Flocculants
| Polymer Flocculants
| Chemical agents that bind suspended particles to enhance sediment removal.
| Chemical agents that bind suspended particles to enhance sediment removal.
| Short-term pumping or treatment where high removal efficiency or fine sediment capture is needed.
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*Treatment for short-term pumping activities
*A high sediment removal rate is required but area too small for wet pond
*Water contains contaminants or a large proportion of fine sediments
*more stringent effluent water quality standards required
*Other conventional BMPs cannot achieve removal rates
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| Active Treatment Systems
| Active Treatment Systems
| Systems combining tanks, flocculants, and filters for precise and high-efficiency contaminant removal.
| Systems combining tanks, flocculants, and filters for precise and high-efficiency contaminant removal.
| Pumping or treatment scenarios needing advanced sediment or contaminant control where space or standards limit conventional BMPs.
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*Treatment for short-term pumping activities
*A high sediment removal rate is required but area too small for wet pond
*Water contains contaminants
*more stringent effluent water quality standards required
*Other conventional BMPs cannot achieve removal rates
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