Download Specifications for Compost Filter Berms in the City Of Plano

Specifications for Compost Filter Berms in the City Of
Plano
Organic Filter Berms
Description: Organic filter berms are contoured runoff and erosion filtration methods
usually used for steeper slopes with high erosive potential.
Purpose:
$ Allows runoff water to penetrate it and continue to flow while filtering sediment and
pollutants from the water. It also slows the flow down, allowing soil particles to settle
out.
$ Reduces the transport of coarse sediment from a construction site by providing a
temporary physical flow barrier to sediment and reducing velocities of overland flow.
$ Controls and filters runoff, protecting areas sensitive to erosion and sedimentation.
$ Bioremediation and prevents water pollution.
$ Manages soil, amending it organically.
Conditions of Use/Limitations:
$ Organic filter berms may be used downslope of all disturbed areas of less than onequarter acre.
$ Do not place single organic filter berm in runoff channels (single concentrated flow).
$ Organic filter berms are not intended to treat concentrated flows (such as ditches or
streams), nor are they intended to treat substantial amounts of overland flow. Any
concentrated flows must be conveyed through the drainage system to a sediment
pond. The only circumstance in which overland flow can be treated solely by a
organic filter berm rather than by a sediment pond, is when the area draining to the
organic filter berm is small.
$ Organic filter berms should only be installed on contours.
$ Organic filter berms work well in many of the same areas as or in conjunction with
erosion control blankets but are the preferred method if the slope exceeds a 4:1
gradient.
$ Organic filter berm size and construction/mix may vary based on slope severity and
the amount of expected flow; larger/multiple berms are recommended for steeper
slopes.
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$ Organic filter berms are typically contoured to the base of the slope but a second
organic filter berms may be used on the shoulder contour of steeper slopes for
added protection.
$ Organic filter berms may be windrow or trapezoidal (allows maximum water
penetration) in shape and should be placed uncompacted on bare soil as soon as
possible. Organic erosion control blankets may be used in front /above or
behind/below the organic filter berms but never under them.
$ Organic filter berms can be planted and seeded at the time of application for
permanent vegetation establishment. The berm can also be spread out and planted
or seeded at the end of the project. Either way, organic filter berms can be left at the
site with no (very little) waste product or cleaning up. Organic matter will help to
amend on-site soils.
$ Locations where other types of BMPs should be used:
o At low points of concentrated runoff
o Below culvert outlet aprons
o Where a previous stand-alone erosion control mix application has failed, unless
multiple controls are installed
o At the bottom of steep perimeter slopes that are more than 50 feet from top to
bottom (i.e., a large up gradient contributing watershed)
o Around catch basins and closed storm systems
Design & Material Specifications:
$ Flow Rate: avg. flow rate 0.3 (gal/sq ft/min) or not greater than 1cfs
$ Drainage Area: contributing drainage area not to exceed 1/4 acre per 100 ft. of
barrier length; the maximum slope above the barrier is 50 ft; and the maximum
gradient behind the barrier is 50 % (2:1).
$ Height: 1 foot (minimum) to 3 feet (maximum)
$ Width: 2 foot (minimum) to 5 feet (maximum)
$ Material:
o Chipped site vegetation, composted mulch, or wood-based mulch can be used to
construct organic filter berms.
o Particulate sizes should be a mix of fine (1/4 to 1/2 inch) and coarse grades of
compost/mulch with no particulate sizes exceeding 3-1/2 inches in length. The
mixture ratio should be or may include a greater fraction of coarser blend
material (1:2) (fine:coarse), “in some instances (1:3)”, compared to ERC
blankets.
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Installation Specifications:
$ On slopes less than 5% or at the bottom of steeper slopes (<2:1) up to 20 feet long,
the barrier (filter berm) must be a minimum of 12" high and a minimum of two feet
wide as measured on the uphill side of the barrier. On longer or steeper slopes, the
barrier should be larger in both height and width to accommodate the higher flow
rate.
$ Place berm parallel to the base of the slope or other affected areas, construct a 1 to
1-1/2 foot high by 2 to 3 foot wide berm of compost/mulch blend.
$ Maximize water filtration ability by constructing a 1-1/2 - 3 foot high trapezoidal berm
which is 2 - 3 ft wide at the top and 3 - 5 ft wide at the base. In general, the base of
the berm should be twice the height of the berm (rex). In extreme conditions a
second berm shall be constructed at the top of the slope.
$ Windrow shaped berms should be between 1 - 2 ft high and 2 to 4 ft wide with a
maximum of 3 ft high x 5 ft wide.
$ The minimum dimensions of the organic filter berm is 1 ft high by 2 ft wide.
$ On steep or excessively long slopes, a second berm/tube may be placed at the top
of the slope or a series of organic filter berms may be constructed down the profile of
the slope.
$ Organic filter berms may be seeded for a more permanent vegetation. Seed loading
approximately 1 lb per 10 lineal ft [1'x2' berm] or 2.25 lbs per 10 lineal ft [1.5'x3'
berm])
$ The organic filter berm must be placed along a relatively level contour. It may be
necessary to cut tall grasses or woody vegetation to avoid creating voids and
bridges that would enable fines to wash under the barrier through the grass blades
or plant stems.
$ Good locations for stand-alone use without reinforcement by other BMPs are:
o At toe of shallow slopes
o One frozen ground, outcrops of bedrock and very rooted forested areas
o At the edge of gravel parking areas and areas under construction
Maintenance Standards:
$ The contractor shall maintain the organic filter berm in functional conditions at all
times and it shall be routinely inspected.
$ There shall be no signs of erosion or concentrated runoff under or around the
organic filter berm.
$ If concentrated flows are bypassing the berm, it must be expanded or augmented by
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trenching into grade.
$ Dimensions of the barrier must be maintained.
$ Contractor shall immediately correct all deficiencies.
Benefits of using Organic Filter Berms:
$ Acts as an effective physical barrier in sheet flow conditions
$ Slow the flow of water over the surface of the soil
$ Retain large volumes of sediment in its mass (pore spaces)
$ Bind and degrade chemical pollutants
$ Effectively perform at a lower cost than silt/sediment fencing
$ Capture and retain moisture, reducing soil moisture loss, thereby facilitating plant
growth
$ Be left “on-site” after project completion, eliminating removal costs
$ Provide suitable microclimate for seed germination
$ Capture blowing snow to increase the insulating effect of winter protection
$ Waste reduction tool - keeps used silt fences out of the landfill and uses recycle
organic materials
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Organic Filter Tube
Description: Organic filter tubes are temporary erosion and sediment control barriers
consisting of compost and compost/mulch blends that are contained in tubular mesh
material.
Organic filter tubes are mesh bags of various sizes filled with specific blends of organic
materials designed to filter and detain flows and sediments generated from drainage
situations.
Purpose:
$ Allows runoff water to penetrate it and continue to flow while filtering sediment and
pollutants from the water. It also slows the flow down, allowing soil particles to settle
out.
$ Minimizes the transport of sediment from a construction, land disturbance, and other
sites by providing a temporary physical barrier to sediment and reducing runoff
velocity.
$ Reduces the transport of coarse sediment from listed sites by providing a temporary
physical flow barrier to sediment and reducing velocities of overland flow.
$ Controls and filters runoff, protecting areas sensitive to erosion and sedimentation
$ Bioremediation and prevents water pollution
$ Manage soil, amending it organically
Conditions of Use/Limitations:
$ Organic filter tubes may be used downslope of all disturbed areas of less than onequarter acre.
$ Organic filter tubes are not intended to treat concentrated flows, nor are they
intended to treat substantial amounts of overland flow. Any concentrated flows must
be conveyed through the drainage system to a sediment pond. The only
circumstance in which overland flow can be treated solely by a organic filter tube
rather than by a sediment pond, is when the area draining to the organic filter tube is
small.
$ Organic filter tubes should only be installed on contours.
$ Organic filter tubes work well in many of the same areas as or in conjunction with
erosion control blankets but are the preferred method if the slope exceeds a 4:1
gradient.
$ Organic filter tubes size and construction/mix may vary based on slope severity and
the amount of expected flow; larger/multiple tubes are recommended for steeper
slopes. Organic filter tubes are typically contoured to the base of the slope but a
second organic filter tube may be used on the shoulder contour of steeper slopes for
added protection. Organic filter tubes should be placed uncompacted on bare soil as
soon as possible. ERC blankets may be used in front or above the organic filter
tubes.
$ Organic filter tubes can be planted and seeded at the time of application for
permanent vegetation establishment. The tube can also be spread out and planted
or seeded at the end of the project. Either way, organic filter tubes can be left at the
site with no (very little) waste product or cleaning up.
$ It may be necessary to stake organic filter tubes on steeper slopes, generally at 6 - 8
ft intervals.
$ Locations where other types of BMPs should be used:
o At low points of concentrated runoff
o Below culvert outlet aprons
o Where a previous stand-alone erosion control mix application has failed, unless
do multiple controls
o At the bottom of steep perimeter slopes that are more than 50 feet from top to
bottom (i.e., a large up gradient contributing watershed)
o Around catch basins and closed storm systems
Design & Material Specifications:
$ Flow Rate: avg. flow rate 0.3 (gal/sq ft/min) or not greater than 1cfs
$ Drainage Area: contributing drainage area not to exceed 1/4 acre per 100 ft. of
barrier length; the maximum slope above the barrier is 25 ft; and the maximum
gradient behind the barrier is 50 % (2:1).
$ Material:
o Chipped site vegetation, composted mulch, or wood-based mulch can be used to
construct organic filter tubes.
o Particulate sizes should be a mix of fine (1/4 to 1/2 inch) and coarse grades of
compost/mulch with no particulate sizes exceeding 3 inches in length. The
mixture ratio should be or may include a greater fraction of coarser blend
material (1:2) (fine:coarse), “in some instances (1:3)”, compared to erosion
control blankets.
Installation Specifications:
$ On slopes less than 5% or at the bottom of steeper slopes (<2:1) up to 25 feet long,
the barrier (filter tube) should be 10-12" in diameter as measured on the uphill side
of the barrier. On longer or steeper slopes, the barrier should a larger diameter to
accommodate the higher flow rate.
$ Place tube parallel to the base of the slope or other affected areas, use a 10" - 12"
diameter filter tube.
$ Use a filter tube up to 18" to 24" in diameter in areas with greater flows or where
maximum sediment control is desired. In high volume, application or on projects
requiring longer than normal construction periods, maximize water filtration ability by
using a > 12" diameter filter tube.
$ On steep or excessively long slopes, a second tube/tube may be placed at the top of
the slope or a series of organic filter tubes may be constructed down the profile of
the slope.
$ Do not place single organic filter tube in runoff channels (single concentrated flow)
as they are not usually effective.
$ The organic filter tube must be placed along a relatively level contour. It may be
necessary to cut tall grasses or woody vegetation to avoid creating voids and
bridges that would enable fines to wash under the barrier through the grass blades
or plant stems.
$ Good locations for stand-alone use without reinforcement by other BMPs are:
o At toe of shallow slopes
o One frozen ground, outcrops of bedrock and very rooted forested areas
o At the edge of gravel parking areas and areas under construction
Maintenance Standards:
$ There shall be no signs of erosion or concentrated runoff under or around the
organic filter tube. If concentrated flows are bypassing the tube, it must be expanded
or augmented by trenching into grade.
$ Dimensions of the barrier must be maintained.
Benefits of using Organic Filter Tubes:
$
$
$
$
$
$
Acts as an effective physical barrier in sheet flow conditions
Slow the flow of water over the surface of the soil
Retain large volumes of sediment in its mass (pore spaces)
Bind and degrade chemical pollutants
Effectively perform at a lower cost than silt/sediment fencing
Capture and retain moisture, reducing soil moisture loss, thereby facilitating plant
growth
$ Can be left “on-site” after project completion, eliminating removal costs
$ Provide suitable microclimate for seed germination
$ Capture blowing snow to increase the insulating effect of winter protection
Erosion Control (ERC) Blanket
Description: ERC blankets are surface applications (ground cover/blanket) of
designated high quality composts on areas with erosive potential.
Purpose:
$ ERC blankets stablizes the soil, prevents splash, sheet, and rill erosion, and
removes suspended soil particles and contaminants from water moving off the site
and into adjacent waterways or storm water conveyance systems.
$ Control erosion on disturbed areas such as construction sites, state DOT
development and planting projects, exposed stream banks, and any disturbed or
excavated land area with a 4:1 slope or less or greater when used in conjunction
with organic filter berm/tube.
$ Primary purpose of the compost erosion control blanket is to protect the soil surface
until vegetation is established.
Conditions of Use/Limitations:
$ Do not use compost erosion control blankets in ditches, streams, or other areas of
concentrated flow unless used in conjunction with and adequately protected by filter
berms/tubes or check dams.
Design & Material Specifications:
$ Particulate sizes should be a mix of screened fine grade 1/4 - 1/2 in and coarse
grade 2-3 in.
$ A mixture ratio of 3:1 (fine:coarse) has been recommended. On thicker applications
>2" a mix ratio of 2:1 (fine:coarse) may be used.
$ Erosion control blankets may be seeded for temporary or long-term vegetation.
Installation Specifications:
$ Erosion Blankets are most efficiently applied using a pneumatic blower
$ Application rates most generally should be between 1-1/2 - 3 inches in depth (135 to
400 cubic yards per acre) with the higher rates for steeper slopes. Some gradual
slopes may require as little at 3/4 inch (100 cubic yards per acre).
$ Long slopes in excess of 50 ft. may require up to 4 - 5 inches depth.
$ It is best to apply the compost layer on the slope contour or up and down the slope
to prevent water from sheeting between the compost material and soil surface.
$ Always apply compost at least 3 ft over the shoulder of the slope or into existing
vegetation where possible to prevent rill formation and transport of the compost
$ ERC blankets are typically placed on up to 4:1 or 2:1 slopes in conjunction with
organic filter berms/tubes at an application rate of 2 to 4 inches. The lower
application rates are typically used in areas of lower potential water flow and on less
severe slopes.
$ For 2:1 slopes or less application should be at a minimum 2 inch depth and 3 ft over
the top of the slope overlapping any existing vegetation.
$ Application depths may be modified for site specific conditions, such as existing
vegetation, climate, characteristics of soil, etc.
$ ERC blankets may be seeded for at the rate of 500 lbs of fescue blend or 300 lbs of
rye per acre for temporary or long-term vegetation.
Maintenance Standards:
$ Contractor shall make periodic inspections of the ERC blanket and make any
repairs as necessary including additional materials
$ Contractor shall inspect the installation before, during and after significant rain
events.
$ Where deficiencies exist, additional ERC blanket material shall be installed
immediately to the required depth.
Benefits of using ERC Blankets:
$ Acts as a buffer to absorb rainfall energy
$ Reduce wind and water erosion immediately
$ Stimulate microbial activity to increase decomposition of organic materials in the soil,
thereby adding to soil structure
$ Prevent soil compaction and crusting, thereby facilitating percolation
$ Slow the flow of water over the surface of the soil
$ Capture and retain moisture, reducing soil moisture loss, thereby facilitating plant
growth
$ Provide suitable microclimate for seed germination
$ Capture blowing snow to increase the insulating effect of winter protection
$ Improve and stabilize soil texture
$
Organic Check Dam
Description: Organic check dams are small, temporary, or permanent dams
constructed across a swale or channel to lower the speed of concentrated flows for a
certain design range of storm events. Organic check dams may be Organic Filter Tube
Check Dams or Organic Filter Berm Check Dams.
Purpose:
$ To reduce the velocity of the water flowing through a swale or channel thereby
reducing the erosion in the swale or channel.
$ Organic check dams also can be used to catch sediment from the channel itself or
from the contributing drainage area as storm water runoff flows through the
structure.
$ Reduces the velocity of the water in a channel and allows sediments and other
pollutants to settle out and be retained.
Conditions of Use/Limitations:
$ Organic check dams are most effective when used in combination with other storm
water and erosion and sediment control measures.
$ Organic check dams should not be used in live, flowing streams.
$ Mesh Bag Organic Check Dams should be used only in small open channels that
drain 8 - 10 acres or less
$ Freestanding Organic Check Dams should be used only in small open channels that
drain 4 - 5 acres or less.
Design & Material Specifications:
Organic Filter Tube Check Dam
$ Flow velocities: should not exceed 12 fps for a 10 year, 24 hour storm frequency;
velocity of water should not exceed 1.5 fps along a swale of 200 ft in length during
the water quality design storm.
$ Material:
o Chipped site vegetation, composted mulch, or wood-based mulch can be used to
construct organic check dams.
o Particle sizes should be a mix of fine (1/4 to 1/2 inch) and coarse grades of
compost/mulch with no particle sizes exceeding 3 inches in length. The mixture
ratio may include a greater fraction of coarser blend material (1:2) (fine:coarse),
“in some instances (1:3)”, compared to ERC blankets.
Organic Filter Berm Check Dam
$ Height: 1-1/2 foot (minimum) to 3 feet (maximum)
$ Width: 2-1/2 foot (minimum) to 5 feet (maximum)
$ Flow velocities: should not exceed 8 fps for a 10 year, 24 hour storm frequency;
velocity of water should not exceed 1.5 fps along a swale of 150 ft in length during
the water quality design storm
$ Material:
o Chipped site vegetation, composted mulch, or wood-based mulch can be used to
construct organic check dams
o Particulate sizes should be a mix of fine (1/4 to 1/2 inch) and coarse grades of
compost/mulch with no particulate sizes exceeding 3-1/2 inches in length. The
mixture ratio should be or may include a greater fraction of coarser blend
material (1:2) (fine:coarse), “in some instances (1:3)”, compared to erosion
control blankets.
Installation Specifications:
$ The center of the dam should be at least 6 inches lower than the edges. Keep
centers of organic check dams at least 6 - 12 inches lower than the outer edges of
natural ground elevation
$ Maximum height should be 3 ft
$ This design creates a weir effect that helps to channel flows away from the banks
and prevent further erosion.
$ Additional stability can be achieved by trenching the dam material into the sides and
bottom of the channel.
$ Construct a 1 ft deep trench immediately upstream of check dams for storage of
settled sediment to reduce maintenance.
Maintenance Standards:
$ Organic check dams should be monitored for performance and sediment
accumulation
$ Remove accumulated leaves and sediments from behind dam when they reach a
depth of 1/2 the original height of the dam
$ Restore materials as necessary for the organic check dams to maintain their correct
height
Organic Check Inlet
Description: Row of anchored/staked mesh bags or continuous organic filter tubes
placed around a storm drain inlet to reduce sediments from entering the storm drain.
Organic Check Inlets may be Organic Filter Tube Check Inlets or Organic Filter Berm
Check Inlet.
Purpose:
$ Reduces the amount of sediment from entering the storm drain system, reduces the
amount of sediment leaving the site.
$ Prevents coarse sediment from entering storm drainage systems by filtering runoff
and retaining sediment before it reaches a drainage inlet or storm sewer system.
Applications:
$ May be used in front of curb/gutter storm water inlet or placed around area storm
water drain.
$ At the outlet of slope drain
$ To protect inlets along paved streets or area inlets
Conditions of Use/Limitations:
$ Suitable where flow rates are low
$ Drainage area less than 1 acre
Design Parameters
$ Overland flow to the inlet should not be greater than 15 liters/second
$ Slope gradient should be 5% or less
Material Specifications:
$ Chipped site vegetation, composted mulch, or wood-based mulch can be used to
construct compost filter tubes.
$ Organic Filter Tube Check Inlet: Particulate sizes should be a mix of fine (1/4 to
1/2 inch) and coarse grades of compost/mulch with no particulate sizes exceeding 3
inches in length. The mixture ratio should be or may include a greater fraction of
coarser blend material (1:2) (fine:coarse), “in some instances (1:3)”, compared to
erosion control blankets.
$ Organic Filter Berm Check Inlet: Particulate sizes should be a mix of fine (1/4 to
1/2 inch) and coarse grades of compost/mulch with no particulate sizes exceeding
3-1/2 inches in length. The mixture ratio should be or may include a greater fraction
of coarser blend material (1:2) (fine:coarse), “in some instances (1:3)”, compared to
erosion control blankets.
Organic Filter Tube Check Inlet Installation Specifications:
$ Use tubes or mesh bags 10" - 24" in diameter
$ Place inlet protection in areas where water can pond and where ponding will not
have adverse impacts
$ Inlet protection must allow for overflow in a severe storm event
$ Additional measures must be considered depending on soil type or flow rates, such
as 2 x 4 frame in front of curb/gutter inlet for support.
$ Uses same material specifications as the Organic Filter Tube.
Free Standing Installation Specifications:
$ May be freestanding (organic filter berm), 18" high x 24" wide, can be constructed
larger if flow warrants.
$ Uses same material specifications as the Organic Filter Berm.
Maintenance Standards:
$ Inspect once per week at active sites and once every two weeks at inactive sites and
within 24 hours of a .5 inch rain event
$ After each storm, clean and remove sediment from behind inlet protection
$ Repair or replace materials as need to ensure proper functioning