[Ord. No. 17-0244, 4-24-2017]
|
BMP No.
|
Title
|
Detail No.
|
Environmental Category
|
Use
| |||||
|---|---|---|---|---|---|---|---|---|---|
|
Erosion Control
|
Pollution Prevention
|
Runoff Manage-ment
|
Sediment Capture
|
Tracking Control
|
Tempor-ary
|
Perman-ent
| |||
|
EC-1
|
Bonded fiber matrix
|
—
|
P
|
X
| |||||
|
EC-2
|
Dust Control
|
—
|
P
|
X
| |||||
|
EC-3
|
Erosion control blankets
|
—
|
P
|
X
|
X
| ||||
|
EC-4
|
Mulching
|
—
|
P
|
X
|
X
| ||||
|
EC-5
|
Rock outlet
|
EC-5
|
P
|
A
|
X
| ||||
|
EC-6
|
Seeding
|
—
|
P
|
X
|
X
| ||||
|
EC-7
|
Sodding
|
EC-7
|
P
|
X
| |||||
|
EC-8
|
Soil binders
|
—
|
P
|
X
| |||||
|
EC-9
|
Streambank protection
|
—
|
P
|
X
| |||||
|
EC-10
|
Temporary stream crossing
|
EC-10
|
P
|
X
| |||||
|
PP-1
|
Non-sediment pollution control
|
—
|
P
|
X
| |||||
|
RM-1
|
Check dam
|
RM-1
|
P
|
A
|
X
| ||||
|
RM-2
|
Diversion — ridge and channel
|
RM-2
|
P
|
X
| |||||
|
RM-3
|
Diversion — storm sewer
|
—
|
P
|
X
| |||||
|
RM-4
|
Gradient terrace
|
RM-4
|
A
|
P
|
A
|
X
| |||
|
RM-5
|
Grass lined channel
|
RM-5
|
A
|
P
|
X
|
X
| |||
|
RM-6
|
Gravel bags
|
RM-6
|
A
|
P
|
A
|
X
| |||
|
RM-7
|
Level spreader
|
RM-7
|
P
|
A
|
X
| ||||
|
RM-8
|
Surface roughening
|
RM-8
|
A
|
P
|
A
|
X
| |||
|
RM-9
|
Temporary slope drain
|
RM-9
|
A
|
P
|
X
| ||||
|
SC-1
|
Filter strip
|
SC-1
|
A
|
A
|
P
|
X
| |||
|
SC-2
|
Inlet protection — block and gravel
|
SC-2
|
P
|
X
| |||||
|
SC-3
|
Inlet protection — fabric drop
|
SC-3
|
P
|
X
| |||||
|
SC-4
|
Inlet protection — gravel and wire mesh
|
SC-4
|
P
|
X
| |||||
|
SC-5
|
Inlet protection — sod filter
|
SC-5
|
A
|
A
|
P
|
X
| |||
|
SC-6
|
Sediment basin
|
SC-6
|
A
|
P
|
X
| ||||
|
SC-7
|
Sediment trap
|
SC-7.1 — 7.3
|
A
|
P
|
X
| ||||
|
SC-8
|
Silt fence
|
SC-8
|
A
|
A
|
P
|
X
| |||
|
TC-1
|
Construc-tion entrance
|
TC-1
|
A
|
A
|
P
|
X
| |||
|
TC-2
|
Construc-tion parking
|
—
|
A
|
P
|
X
| ||||
|
TC-3
|
Construc-tion Road
|
TC-3
|
A
|
A
|
P
|
X
| |||
|
TC-4
|
Washdown station
|
TC-4
|
P
|
X
| |||||
|
Note:
|
|
P = Primary BMP function
|
|
A = Additional uses
|
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. A bonded fiber matrix (BFM) is a hydraulically
applied continuous layer of elongated fiber strands held together
by a water-resistant bonding agent designed to protect exposed soil
by eliminating direct impact of precipitation. BFMs adhere directly
to the surface of the soil, eliminating gaps between the product and
the soil; therefore no special treatment is required at the upstream
end of the BFM. BFMs have a high water-holding capacity, but do not
form a water-insensitive crust that would inhibit plant growth. BFMs
biodegrade completely into material known beneficial to plant growth.
B.
Where BMP Is To Be Installed. Typically installed on slopes where
erosion control blankets are impractical and other mulching methods
are inadequate.
C.
Conditions For Effective Use Of BMP.
Type of flow: Sheet flow only.
D.
When BMP Is To Be Installed. Immediately after completion of a phase
of grading.
E.
Installation/Construction Procedures. Follow manufacturer's recommendations
to maximize usefulness.
G.
Site Conditions For Removal. Typically left in place to degrade naturally.
H.
Typical Details. Not applicable.
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. Control measures designed to reduce the transport
of dust, thereby preventing pollutants from infiltrating into stormwater.
Examples for construction activities include, vegetative cover, wind
barriers, minimization of soil disturbance, spray-on adhesives, tilling,
chemical treatment and water sprays.
B.
Where BMP Is To Be Installed. Critical in areas of exposed soil.
C.
Conditions For Effective Use Of BMP. A combination of the following
actions should be used to help reduce the dust and air pollution at
a construction site.
1.
Minimize Concurrent Areas Of Soil Disturbance. Phase work to
the extent practical.
2.
Vegetative Cover. For areas not subjected to traffic, vegetation
provides the most practical method of dust control and should be established
as early as possible. Temporary vegetation should also be used. See
"Seeding" and "Sodding" BMPs for additional information.
3.
Sprinkling. The site can be sprinkled with water until the surface
is moist. This practice is effective for dust control on large areas,
haul routes or other traffic routes, but constant repetition is required
for effective control.
4.
Tilling. Roughen the surface and bring clods to the surface.
This is an emergency measure that should be used before soil blowing
starts. Begin tillage on windward side of the site. Chisel plows with
shanks spaced about twelve (12) inches to eighteen (18) inches apart
and spring toothed harrows are examples of equipment that may produce
the desired effect. See "Surface Roughening BMP" for additional information.
5.
Wind Barriers. Solid board fences, snow fences, burlap fences,
crate walls and similar materials can be used to control air currents
and blowing soil. Barriers placed at right angles to prevailing wind
currents at intervals of about ten (10) times their height are effective
in controlling soil blowing.
6.
Street Cleaning. Paved areas that have soil on them from construction
sites should be cleaned continuously, at least daily, utilizing a
street sweeper or bucket type endloader or scraper.
7.
Mulching. This practice offers a fast and effective means of
controlling dust where properly applied. Binders and tackifiers should
be used on organic mulches. Mulching is not recommended for areas
with heavy traffic. See "Mulching" BMP for additional information.
Note: If calcium chloride or spray-on adhesives are used for
dust control, a permit may be required from the Missouri Department
of Natural Resources.
D.
When BMP Is To Be Installed. Routinely, especially in advance of
and during periods of dry weather.
E.
Installation/Construction Procedures. See conditions for effective
use above.
F.
O&M Procedures. Inspect daily and renew as needed.
G.
Site Conditions For Removal. Maintain practices until all disturbed
areas are vegetated or paved and blowing soil is no longer a concern.
H.
Typical Details. Not applicable.
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. An erosion control blanket is a preformed protective
blanket of plastic fibers, straw or other plant residue designed to
protect soil from the impact of precipitation and overland flow and
retain moisture to facilitate establishment of vegetation. There are
many products on the market designed for a variety of applications.
B.
Where BMP Is To Be Installed. Typically installed on slopes or in
channels prior to establishment of vegetation.
C.
Conditions For Effective Use Of BMP. Several factors, such as soil
conditions, steepness and length of slope, depth of flow, runoff velocities
and time required to establish desired vegetation, influence the choice
of product. Manufacturer's recommendations should be followed. Products
are available for a variety of uses:
1.
Netting. Synthetic or natural fiber mesh installed over disturbed
area to hold organic mulch and/or seed in place.
2.
Biodegradable Erosion Control Blanket. Natural fiber blanket
held together by netting to provide temporary erosion protection on
slopes and channels.
3.
Permanent Erosion Control Blanket. Synthetic blanket material
that provides permanent erosion control on slopes and channels with
increased water flow.
4.
Turf Reinforcement Mat. Three-dimensional permanent synthetic
mat that provides a matrix to greatly reinforce the root system of
the desired vegetation for permanent erosion protection in high flow
channels and on critical slopes.
D.
When BMP Is To Be Installed. Dependent upon intended use —
immediately after completion of a phase of grading or installation
of vegetation.
E.
Installation/Construction Procedures. Follow manufacture's recommendations
and specifications, particularly noting requirements for check slots,
fastening devices and need for firm contact with soil.
F.
O&M Procedures.
1.
Inspect at least every week and after every storm until adequate
vegetation is established.
2.
Repair erosion and/or undermining at top of slope.
3.
Repair undermining beneath blankets — pull back the blanket(s),
fill and compact eroded area, revegetate and then secure blanket(s)
firmly.
4.
Reposition or replace blankets that have moved along the slope
or channel and secure firmly.
5.
Replace damaged blankets.
G.
Site Conditions For Removal. Temporary blankets will generally degrade
naturally; permanent blankets remain in place.
H.
Typical Details. Not applicable.
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. A layer of organic material designed to protect
exposed soil or freshly seeded areas from erosion by eliminating direct
impact of precipitation and slowing overland flow rates. Mulch materials
may include, but are not limited to, such things as grass, hay, straw,
wood chips, wood fibers and shredded bark.
B.
Where BMP Is To Be Installed. Typically installed on seeded areas
for temporary use and in landscaped areas for permanent use.
C.
Conditions For Effective Use Of BMP.
|
Type of flow:
|
Sheet flow only
|
|---|---|
|
Slopes:
|
See attached chart (at end of this Section) for types of mulch
acceptable as a function of slope length and steepness
|
|
Mulching rates:
|
See attached table (at end of this Section)
|
D.
When BMP Is To Be Installed. Immediately after grading landscaped
areas or seeding other areas.
E.
Installation/Construction Procedures.
1.
Install upstream BMPs to protect area to be mulched.
2.
Rough grade area and remove all debris larger than one (1) inch
if area is to be vegetated and mowed in the future, larger than two
(2) inches if area is to be permanently mulched.
3.
If area is to be seeded, follow requirements of seeding BMP.
4.
Spread mulch and anchor by punching it into the ground, using
netting, peg and twine, or tacking with liquid binder.
G.
Site Conditions For Removal. Temporary mulch should be removed when
adequate vegetation is established.
H.
Typical Details. Type of mulch required for various slopes and application
rates attached.
 |
|
General Mulch Recommendations To Protect From Splash And Sheet
Flow
| |||
|---|---|---|---|
|
Material
|
Rate Per Acre
|
Requirements
|
Notes
|
|
Straw
|
2 — 2 1/2 tons
|
Dry, unchopped, unweathered; avoid weeds
|
Spread by hand or machine; must be tacked or tied down
|
|
Wood fiber or wood cellulose
|
1/2 — 1 ton
|
Use with hydroseeder; may be used to tack straw. Do not use
in hot, dry weather
| |
|
Wood chips
|
5 — 6 tons
|
Air dry. Add nitrogen fertilizer at 12 lb/ton
|
Apply with blower, chip handler or by hand. Not for fine turf
areas
|
|
Bark
|
35 yard3
|
Air dry, shredded or hammer milled, or chips
|
Apply with mulch blower, chip handler or by hand. Do not use
asphalt tack
|
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. A rock apron installed over a geotextile fabric
at a point of concentrated discharge, designed to slow the velocity
of flow and protect the receiving area from erosion.
B.
Where BMP Is To Be Installed. Installed at BMP outlets, for example
at the end of pipe slope drains, the emergency overflow or outlet
pipe of a sediment basin.
C.
Conditions For Effective Use Of BMP.
|
Type of flow:
|
Concentrated flow
|
|
Flow at outlet:
|
Maximum velocity of 10 fps
|
D.
When BMP Is To Be Installed. With the construction of the upstream
BMP that creates the concentrated discharge.
G.
Site Conditions For Removal. Removed concurrently with upstream BMP.
H.
Typical Detail. EC-5.
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. Establishment of vegetation by spreading grass
seed designed to protect exposed soil from erosion by eliminating
direct impact of precipitation and slowing overland flow rates. Once
established, the vegetative cover will also filter pollutants from
the runoff.
B.
Where BMP Is To Be Installed. Exposed soil after a phase of rough
or finish grading has been completed or areas where no activity will
occur for thirty (30) days.
C.
Conditions For Effective Use Of BMP.
|
Type of flow:
|
Sheet flow
|
|
Contributing slope length:
|
30 foot maximum for 3:1 slopes
|
|
50 foot maximum for slope between 3:1 and 10:1
| |
|
100 foot maximum for slopes under 10%
| |
|
Minimum rates:
|
See attached chart(s)
|
|
Acceptable dates:
|
See attached chart
|
D.
When BMP Is To Be Installed. Immediately after rough or finished
grading is completed.
E.
Installation/Construction Procedures.
1.
Install upstream BMPs to protect area to be seeded.
2.
Rough grade area and remove all debris larger than one (1) inch
in diameter and concentrated areas of smaller debris.
3.
Install stabilization grids, if needed.
4.
Mix soil amendments (lime, fertilizer, etc.) into top three
(3) inches to six (6) inches of soil as needed.
5.
Plant seed one-fourth (1/4) to one-half (1/2) inch deep.
6.
Roll lightly to firm surface.
7.
Cover seeded area with mulch unless seeding completed during
optimum spring and summer dates.
8.
Install additional stabilization (netting, bonded fiber matrix,
etc.) as required.
9.
Water immediately — enough to soak four (4) inches into
soil without causing runoff.
F.
O&M Procedures.
1.
Inspect at least every week and after every storm.
2.
Protect area from vehicular and foot traffic.
3.
Reseed areas that have not sprouted within twenty-one (21) days
of planting.
4.
Repair damaged or eroded areas and reseed and stabilize as needed.
5.
Do not mow until four (4) inches of growth occurs.
6.
During the first four (4) months, mow no more than one-third
(1/3) the grass height.
7.
Refertilize during second growing season.
G.
Site Conditions For Removal. Does not require removal, but temporary
seeding can be removed immediately prior to work returning to an area.
H.
Typical Details. Minimum seeding rates and acceptable dates for work
attached.
[Ord. No. 17-0244, 4-24-2017]
|
Dates For Seeding
| ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Permanent Seeding
|
Jan
|
Feb
|
Mar
|
Apr
|
May
|
Jun
|
Jul
|
Aug
|
Sep
|
Oct
|
Nov
|
Dec
|
|
Tall Fescue
|
O
|
O
|
O
|
O
|
O
| |||||||
|
Smooth Brome
|
O
|
O
|
O
|
O
|
O
| |||||||
|
Fescue and Brome
|
O
|
O
|
O
|
O
|
O
|
O
| ||||||
|
Fescue, Rye and Bluegrass
|
A
|
A
|
O
|
O
|
O
|
P
|
P
|
O
|
O
|
P
|
P
|
A
|
|
Temporary seeding
|
Jan
|
Feb
|
Mar
|
Apr
|
May
|
Jun
|
Jul
|
Aug
|
Sep
|
Oct
|
Nov
|
Dec
|
|
Rye or Sudan
|
A
|
A
|
O
|
O
|
O
|
O
|
O
|
O
|
O
|
O
|
A
|
A
|
|
Oats
|
A
|
O
|
O
|
O
|
O
|
O
|
O
|
O
| ||||
|
O = Optimum seeding dates
| ||||||||||||
|
A = Acceptable seeding dates
| ||||||||||||
|
P = Permitted seeding dates with reseeding 2 months
later — Initially use 50% of seed and 75% of fertilizer. Reseed
with additional 75% seed and remaining fertilizer.
| ||||||||||||
|
Minimum Fertilizer And Seeding Rates
| ||
|---|---|---|
|
Permanent Seeding*
|
Lb/Acre
|
Lb/1,000 Square Feet
|
|
Tall Fescue
|
300
|
7
|
|
Smooth Brome
|
200
|
4.6
|
|
Mixture #1
|
250
|
5.7
|
|
Mixture #2
|
210
|
4.8
|
|
Mixture #1 — Tall Fescue @ 150 lbs/acre and Brome @ 100
lbs/acre
Mixture #2 — Tall Fescue @ 100 lbs/acre, Perennial Rye
Grass @ 100 lbs/acre and Kentucky Bluegrass @ 10 lbs/acre
*Seeding rate for slopes in excess of 20% (5:1) shall be 10
lb/1,000 square feet
| ||
|
Temporary Seeding
|
Lb/Acre
|
Lb/1,000 Square Feet
|
|---|---|---|
|
Rye or Sudan
|
150
|
3.5
|
|
Oats
|
120
|
2.8
|
|
Fertilizer
|
Permanent Seeding
(Lb/Acre)
|
Temporary Seeding
(Lb/acre)
|
|
Nitrogen
|
45
|
30
|
|
Phosphate
|
65
|
30
|
|
Potassium
|
65
|
30
|
|
Lime-ENM
|
600
|
600
|
|
ENM — Effective neutralizing material per State evaluation
of quarried rock
| ||
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. A three-fourth (3/4) to one (1) inch thick
mat of vigorous turf, free of disease, insects and weeds. Sod prevents
raindrops from disrupting the soil structure and causing erosion.
Sod slows water runoff and acts as a filter when sediment laden runoff
crosses over the sodded area.
B.
Where BMP Is To Be Installed. Typically installed in areas requiring
immediate erosion protection, such as swales or detention ponds and
as filter strips, around inlets and adjacent to curbs. Also installed
in areas requiring immediate aesthetic appearance or function such
as entrances to new subdivision and off-site construction areas.
C.
Conditions For Effective Use Of BMP.
Type of flow: Sheet flow and low concentrated flows with velocities
less than five (5) fps.
D.
When BMP Is To Be Installed. Immediately after flash grading, installation
of area inlets and installation of underground services and foundations
of new homes.
E.
Installation/Construction Procedures.
1.
Rough grade area and remove all debris larger than one-half
(1/2) inch in diameter and concentrated areas of smaller debris.
2.
Soil preparation of area to be sodded shall be determined by
tests to determine lime and fertilizer requirements. Soil amendments
shall be mixed into top three (3) to six (6) inches of soil by disking
or other means.
3.
Level and roll soil lightly to provide an even grade and firm
the surface. Soil should not be excessively wet or dry.
4.
Lay first (1st) row of sod perpendicular to the slope or direction
of flow. Butt subsequent rows tight against previous rows with strips
staggered in brick-like pattern. Fill minor gaps with good soil and
roll entire surface to ensure contact.
5.
Stake, staple and/or net corners and centers of sod strips as
required.
6.
Water immediately after installation enough to soak four (4)
inches into soil without causing runoff.
F.
O&M Procedures.
1.
Water sod daily for three (3) weeks — enough to soak four
(4) inches into soil without causing runoff.
2.
Reposition areas of sod that has moved along the slope.
3.
Remove sediment accumulations — replace sod if necessary.
4.
Repair any eroded areas, replace sod and stabilize as needed.
5.
Do not mow until three (3) inches of new growth occurs. During
the first four (4) months, mow no more than one-third (1/3) the grass
height.
G.
Site Conditions For Removal. Not applicable.
H.
See Detail. Drawing EC-7.
|
DRAWING EC-7 SODDING
 |
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. A material sprayed onto the surface of exposed
soils designed to protect against erosion for wind or runoff. The
useful life of most products is three (3) to six (6) months. Examples
of materials used include vegetable-based adhesives, copolymers, petroleum
oils and resin-emulsions.
B.
Where BMP Is To Be Installed. Typically used in disturbed areas and
in combination with other BMPs such as perimeter controls, seeding
or mulching.
C.
Conditions For Effective Use Of BMP.
Type of flow: Sheet flow
D.
When Bmp Is To Be Installed. Immediately after completion of a phase
of grading.
E.
Installation/Construction Procedures. Follow manufacturer's recommendations
to maximize usefulness and avoid formation of pools or impervious
areas where stormwater cannot infiltrate.
G.
Site Conditions For Removal. Typically left in place to degrade naturally.
H.
Typical Details. Not applicable.
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. A vegetative, structural or combination treatment
of streams designed to stabilize the stream and reduce erosion. It
is important to note that a systemic analysis of the entire reach
of stream must be conducted in order to avoid unintended negative
impacts on a stream as a result of a corrective action at an isolated
location. A wide array of products and methodologies can be used to
stabilize streams: live stakes; cellular confinement matrices; articulated
block pavers; rip-rap; gabion baskets; turf reinforcement mats; fabric
formed revetments; cedar tree revetments; straw wattles; grade control
structures; stilling basins; etc.
B.
Where BMP Is To Be Installed. Open channels downstream from developed
areas.
C.
Conditions For Effective Use Of BMP. Acceptable methods vary widely
due to the unique nature of each reach of channel. Design considerations
include: current and future watershed conditions; discharge; velocity;
sediment load; channel slope; control of bottom scour (incising);
soil conditions; compatibility with other improvements; changes in
channel alignment; and protection and maintenance of fish and wildlife
habitats and existing tree canopy.
D.
When BMP To Be Installed. Well in advance of disturbing any upstream
areas in order to give plant material a relatively long period to
become established and allow ample time for inspection and necessary
repairs during construction of the remainder of the development.
E.
Installation/Construction Procedures. Procedures are specific to
materials used. General construction principles include:
1.
Stabilize the channel bottom first to prevent incising and knick
points from undermining the bank protection.
2.
Start and stop bank protection at stable points along the channel.
3.
Minimize the size of all disturbed areas and stabilize as soon
as each phase of construction is complete.
4.
Use other BMPs to prevent runoff from disturbing the streambank
protection area until it has been completed.
5.
Store all construction materials well away from the stream.
6.
At the end of each workday, move all construction equipment
out of and away from the stream to prevent flooding.
7.
Avoid steep slopes on the streambank.
8.
Fence the construction area and post warning signs if trespassing
or vandalism is likely.
F.
O&M Procedures.
1.
Inspect at least every week and after every storm during construction
and once each season thereafter.
2.
Repair, relocate or add BMPs protecting channel until the streambank
protection is operational.
3.
Remove sediment as needed for proper establishment of protection
measures.
4.
Repair gaps in vegetative cover by replacing plants or designing
alternative methods/materials.
5.
Repair structural systems as needed.
G.
Site Conditions For Removal. Not applicable.
H.
Typical Details. Not applicable.
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. A stabilized stream crossing designed to protect
the stream banks while facilitating access for construction vehicles
and equipment. Use of temporary stream crossings is discouraged —
crossings are a direct source of pollution and should be avoided if
alternatives are feasible. If the work involves construction below
the normal water of a defined channel, permit will need to be obtained
from the U.S. Army Corps of Engineers prior to the County approving
the SWPPP.
B.
Where BMP Is To Be Installed. At locations where work and disruption
in creek can be minimized.
C.
Conditions For Effective Use Of BMP. When no other feasible alternative
exists, crossing streams may be permitted. Design considerations include:
current and proposed watershed conditions; average and peak discharge
(2-year, 24-hour storm); effect on water surface elevation off site;
velocity; sediment removal; and protection of fish and wildlife habits
and existing trees. Criteria for certain types of crossings follow.
Low water crossing. Any constant flow less than three (3) inches
deep; light traffic; bank height less than five (5) feet; perpendicular
to flow or with slight upstream arc.
Culvert. Sized for 2-year, 24-hour storm with one (1) foot freeboard
and no flooding of off-site areas; pipe parallel to flow; embankment
perpendicular to channel or with slight upstream arc; rip-rap on exposed
faces sized for overtopping during a peak storm period.
D.
When BMP Is To Be Installed. During dry periods in advance of need
to cross stream.
E.
Installation/Construction Procedures. Procedures are specific to
type of crossing used. Procedures for low water crossings and culverts
include:
1.
Ensure that all necessary materials are on site before beginning
work.
2.
Provide a stable means to by-pass normal channel flow prior
to disturbing channel.
3.
Scarify and stabilize channel bottom to provide even foundation
for crossing.
4.
Install culvert, if needed — place clayey soil to required
dimensions around pipe.
5.
Grade and compact access ramps.
6.
Place and compact soil embankment for culvert; rip-rap for low
water crossing, if needed.
7.
Install fabric under crossing and to required distance from
creek bank.
8.
Install stone on access ramps and cellular confinement system
for driving surface of crossing.
9.
Place rip-rap on faces of and downstream from culvert embankment.
G.
Site Conditions For Removal. Remove as soon as alternative access
is available. All foreign materials should be removed from creek.
The streambed and banks should be returned to the original contour
and should be stabilized if necessary.
H.
See Detail. Drawing EC-10.
|
DRAWING EC-10 TEMPORARY STREAM CROSSING — TYPICAL
BMP DETAIL
 |
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. Control measures designed to prohibit chemicals,
hazardous materials, solid waste, human waste and construction debris
from polluting stormwater. Pollutants carried in solution or as surface
films on runoff will be carried through most erosion control and sediment
capture BMPs. Keeping substances like fuel, oil, asphalt, paint, solvents,
fertilizer, soil additives, concrete wash water, solid waste, human
waste and construction debris from polluting runoff can be accomplished
to a large extent through good housekeeping on the site and allowing
the manufacturer's recommendations for disposal.
B.
Where BMP Is To Be Installed. Temporary sanitary facilities, collection,
storage and fueling areas should be located on-site in an area that
does not receive a substantial amount of runoff from upland areas
and does not drain directly to lakes, creeks, streams, rivers, sewers,
ground water, wetlands or road ditches.
C.
Conditions For Effective Use Of BMP.
1.
Reduction in pollutants depends heavily on how construction
personnel perform their duties. An effective management system requires
training and signage to promote proper storage, handling and disposal
of materials. Follow up observations of actions and inspection of
storage areas by management personnel is also required.
2.
Plans should contain notes clearly stating requirements for
addressing potential pollutants.
3.
Fueling areas and storage areas for hazardous materials should
be protected by berms or other means of catching leaks or spills.
D.
When BMP Is To Be Installed. Immediately following installation of
construction entrance and wash station.
E.
Installation/Construction Procedures.
1.
Place waste receptacles near area of work.
2.
Construct protective berm or other devices around fueling and
hazardous materials storage areas.
3.
Install appropriate signage.
4.
Post guidelines for proper handling, storage and disposal of
materials and emergency spill cleanup on site.
5.
Provide sufficient temporary toilet facilities to serve the
number of workers on the site.
G.
Site Conditions For Removal. Maintain practices until all construction
on the site has been completed.
H.
Typical Details. General pollution prevention notes attached.
[Ord. No. 17-0244, 4-24-2017]
A.
Pollution prevention procedures are as follows:
2.
Containers shall be provided for collection of all waste material
including construction debris, trash, petroleum products and any hazardous
materials to be used on site. All waste material shall be disposed
of at facilities approved for that material.
3.
No waste materials shall be buried on site.
4.
Mixing, pumping, transferring or otherwise handling construction
chemicals such as fertilizer, lime, asphalt, concrete drying compounds
and all other potentially hazardous materials shall be performed in
an area away from any watercourse, ditch or storm drain.
5.
Equipment fueling and maintenance, oil changing, etc., shall
be performed only in an area designated for that purpose. The designated
area is equipped for recycling oil and catching spills.
6.
Concrete wash water shall not be allowed to flow directly to
storm sewers, streams, ditches, lakes, etc., without being treated.
A sump or pit shall be constructed to contain concrete wash water.
7.
If substances such as oil, diesel fuel, hydraulic fluid, antifreeze,
etc., are spilled, leaked or released onto soil, the soil shall be
dug up and disposed of at a licensed sanitary landfill (not a construction/demolition
debris landfill). Spills on pavement shall be absorbed with sawdust,
kitty litter or a product designed for that purpose and disposed of
at a licensed sanitary landfill. Hazardous or industrial wastes such
as most solvents, gasoline, oil-based paints and cement curing compounds
require special handling. These materials will be removed from the
site and recycled or disposed of in accordance with MoDNR requirements.
8.
State law requires the party responsible for a petroleum product
spill in excess of fifty (50) gallons to report the spill to MoDNR
(537-634-2436) as soon as practical after discovery. Federal law requires
the responsible party to report any release of oil if it reaches or
threatens a sewer, lake, creek, stream, river, ground water, wetland,
or area like a road ditch that drains into one (1) of the above.
9.
Sufficient temporary toilet facilities to serve the number of
workers on the site shall be provided. The facilities shall be serviced
frequently to maintain a sanitary condition.
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. A small dam built within a drainage swale or
temporary diversion channel designed to pond water and cause sediment
to settle out. Dams can be constructed of rock, sand bags or gravel
bags.
B.
Where BMP Is To Be Installed. At intervals along drainage swales
or channels. The top of the downstream check dam should be level with
the base of the upstream check dam.
C.
Conditions For Effective Use Of BMP.
|
Type of flow:
|
Moderate concentrated flow
|
|
Contributing area:
|
Maximum of 2 acres
|
|
Channel slope:
|
Maximum of 2%
|
D.
When BMP Is To Be Installed. Prior to disturbance of natural vegetation
in contributing drainage area; immediately after construction of drainageway.
F.
O&M Procedures.
1.
Inspect at least every week and after every storm.
2.
Remove trash and leaf accumulation.
3.
Remove sediment buildup once it reaches one-half (1/2) depth
of check dam or twelve (12) inch depth, whichever is less.
4.
Restore dam structure to original configuration to protect banks.
5.
Replace rock on upstream face of dam if ponding does not drain
in reasonable timeframe.
G.
Site Conditions For Removal. Remove after contributing drainage areas
have been adequately stabilized and vegetation is adequately established
in drainageway. Regrade and vegetate area of check dam.
H.
Typical Details. Drawing RM-1.
|
DRAWING RM-1 CHECK DAM
 |
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. A compacted earth or gravel ridge, excavated
channel or a combination of ridge and channel designed to direct runoff
away from or around disturbed areas and cause sediment to settle out.
Diversions built on a level contour are used in combination with temporary
slope drains to provide adequate conveyance. Diversions built with
positive drainage slopes release runoff into additional BMPs such
as sediment traps or level spreaders. BMPs such as check dams can
also be used in diversion channels to slow velocities.
B.
Where BMP Is To Be Installed. At top of disturbed slopes and other
sensitive areas to protect them from upstream runoff; intermediate
locations along long slopes to reduce slope length; and perimeter
of construction area.
C.
Conditions For Effective Use Of BMP.
|
Type of flow:
|
Sheet flow and low volume concentrated flows
|
|
Contributing area:
|
Contributing slope length — 300 feet maximum; 100 feet
for slopes greater than 5%
|
|
Channel lining:
|
Diversions of slopes exceeding 5% should be lined with gravel
or other material due to high velocity
|
D.
When BMP Is To Be Installed. Prior to disturbance of natural vegetation
on slopes and at intervals during construction of fill slopes.
E.
Installation/Construction Procedures.
1.
Grade and compact channel and/or ridge.
2.
Install vegetation or protective lining.
3.
Stabilize outfall area as depicted on plan.
4.
Install lathe or post at each end of diversion and at twenty
(20) foot intervals. Mark maximum allowable sediment depth at one-half
(1/2) the depth of the channel.
G.
Site Conditions For Removal. After permanent vegetation of slope
is established.
H.
Typical Detail. Drawing RM-2.
|
DRAWING RM-2 DIVERSIONS — RIDGE AND CHANNEL
 |
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. A stabilized diversion designed to redirect
the flow of a storm sewer system while work that impacts the system
is performed. Diversions can be in the form of pipes or channels and
can handle the flows of creeks or streams or at the outlets of storm
sewer pipes. Diversion channels must be stabilized to prevent erosion.
Diversions can release runoff directly into the storm sewer system
downstream or to additional BMPs such as sediment traps, sediment
basins or rock outlets. BMPs, such as check dams, can also be used
in diversion channels to slow velocities.
B.
Where BMP Is To Be Installed. Around locations that impact the flow
of runoff in storm sewer systems. Diversion route should be located
to minimize impact on other construction activities.
C.
Conditions For Effective Use Of BMP.
|
Type of flow:
|
Concentrated flow
|
|
Capacity of diversion device:
|
Sized for 15-year, 20-minute storm, while minimizing velocity
of flow.
|
D.
When Bmp Is To Be Installed. Prior to disturbance of area impacting
the function of the storm sewer system.
E.
Installation/Construction Procedures.
1.
Excavate diversion area except for area of upstream connection.
2.
Compact as required to place diversion properly.
3.
Install pipe bedding or channel lining as required.
4.
Install pipe and backfill to required dimensions.
5.
Install additional BMPs as designed, both in the diversion and
downstream.
6.
Make final connection to upstream storm sewer system.
G.
Site Conditions For Removal. Remove after work impacting existing
storm sewer has been completed and stabilized.
H.
Typical Details. Not applicable.
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. Defined swales constructed at regular intervals
along the face of a slope designed to reduce erosion by capturing
surface runoff and directing it to an adequate, stable outlet. Due
to the steep slopes needed to create the terrace, swales may only
be created by construction of earth ridges.
B.
Where BMP Is To Be Installed. Typically installed on long steep slopes
on which erosion is a concern. Gradient terraces should not be constructed
in sandy or rocky soil.
C.
Conditions For Effective Use Of BMP.
|
Type of flow:
|
Sheet flow
|
|
Slope characteristics:
|
Maximum of 3:1 slope
|
|
Contributing slope length:
|
Maximum of 30 feet for slopes steeper than 4:1
|
|
Maximum of 50 feet for 4:1 and flatter
| |
|
Outlet:
|
HGL of outlet BMP less than or equal HGL of terrace in 15-year,
20-minute storm.
|
D.
When BMP Is To Be Installed. Installed as fill is constructed. On
existing slopes, terraces should be graded prior to removal of vegetation.
F.
O&M Procedures.
G.
Site Conditions For Removal. Not applicable.
H.
Typical Detail. Drawing RM-4.
|
DRAWING RM-4 GRADIENT TERRACES
 |
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. Trapezoidal or parabolic stormwater conveyance
channel lined with vegetation, designed to direct runoff and reduce
the flow velocity of concentrated runoff. Channels should outlet into
sediment traps, detention/retention basins or other stable outlets.
In areas with seasonally high water tables or seepage problems, subsurface
drains are included under the channel. Grassed channels have a limited
ability to control runoff from large storms and are often used in
combination with other BMPs such as subsurface drains and rip-rap
stabilization.
B.
Where BMP Is To Be Installed. Used in areas where erosion-resistant
conveyances are needed, including areas with highly erodible soils
and moderately steep channel slopes — less than five percent
(5%). Channels should only be installed where space is available for
a relatively large cross section. Channels should not make sharp,
unnatural changes in direction or grade of flow.
C.
Conditions For Effective Use Of BMP.
|
Type of flow:
|
Concentrated flow
|
|
Flow properties:
|
Maximum velocity of 5 fps
|
D.
When BMP Is To Be Installed. Immediately after clearing, prior to
upstream grading activities.
E.
Installation/Construction Procedures.
1.
Excavate and shape channel to required section.
2.
Install subsource drain, if needed.
3.
Install erosion-resistant lining, such as rip-rap or sod, at
concentrated inflow points.
4.
Prepare and fertilize soil.
5.
Install sod, seed with protection such as erosion control blankets
or turf reinforcement mats or hydroseeding.
6.
Sod should be perpendicular to flow with a brick-like joint
pattern. Stake, staple and/or net corners and centers of sod strips
as required.
7.
Install lathe or post at each end of channel and at twenty (20)
foot intervals. Mark maximum allowable sediment depth at six (6) inches.
8.
Water immediately after installation, enough to soak four (4)
inches into soil without causing runoff.
F.
O&M Procedures.
1.
Water sod daily for three (3) weeks — enough to soak four
(4) inches into soil without causing runoff.
2.
Inspect at least every week and after every storm for the duration
of construction or six (6) months, whichever is longer.
3.
Remove any blockage and/or debris from channel, channel outlet
or road crossings.
4.
Reposition areas of sod that have moved.
5.
Remove sediment accumulation once sediment reaches six (6) inches
in depth, as indicated on the monitoring posts — replace vegetation
if necessary.
6.
Repair any eroded areas, revegetate and stabilize as needed.
7.
Do not mow until three (3) inches of new growth occurs. During
the first four (4) months do not mow more than one-third (1/3) the
grass height.
G.
Site Conditions For Removal. Temporary channels can be removed after
permanent storm sewer system is operational.
H.
Typical Detail. Drawing RM-5.
|
DRAWING RM-5 GRASS LINED CHANNEL
 |
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. Open mesh nylon or burlap bags of gravel designed
to pond water and cause sediment to settle out. Gravel bags can be
used alone or as a part of other best management practices.
B.
Where BMP Is To Be Installed. Suitable for multiple uses including
disrupting concentrated flows, redirecting concentrated flows, capturing
sediment by ponding and anchoring other devices. Can be used in place
of silt fence, rock check dams, rock outlet protection, ridge diversions,
inlet protection and level spreader or as part of the structure of
sediment basins, sediment traps, storm drain diversions and structural
stabilization of streams.
C.
Conditions For Effective Use Of BMP.
|
Type of flow:
|
Sheet flow and concentrated flow
|
D.
When BMP Is To Be Used. Dependent upon function it is designed to
perform.
E.
Installation/Construction Procedures.
1.
Fill bags approximately two-thirds (2/3) full.
2.
Grade and stabilize soil on which bags are to be placed.
3.
Install centerline of bags on bottom row.
4.
Place remaining bags on each side of center — minimum
width of bottom row is three (3) bags.
5.
Place upper rows of bags, staggering ends in brick-like pattern.
F.
O&M Procedures.
1.
Inspect at least every week and after every storm.
2.
Replace and stabilize any damaged bags or bags that have moved
out of place.
3.
When silt builds up in front of a row of gravel bags performing
the function of silt fence, move the row of bags in front of the sediment
buildup. This "new row" will capture additional sediment and keep
concentrated flows from reaching the previous sediment deposit.
4.
Remove sediment at rows of bags used as weirs or lips. Bags
may be repositioned to facilitate removal of sediment.
G.
Site Conditions For Removal. Completion of upstream work and vegetation
of contributing runoff areas.
H.
Typical Detail. Drawing RM-6.
|
DRAWING RM-6 GRAVEL BAGS
 |
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. A level graded area designed to slow and spread
runoff and release it as sheet flow to a stabilized area. The level
spreader outlet can be stabilized by vegetation, erosion control blankets
or a combination wood timber and gravel. Undisturbed vegetated areas
with a maximum slope of ten percent (10%) at the outfall do not require
stabilization.
B.
Where BMP Is To Be Installed. At downstream end of diversion devices
and upstream end of filter strips.
C.
Conditions For Effective Use Of BMP.
|
Type of flow:
|
Sheet flow and concentrated flow
|
|
Contributing area:
|
Flow from 15-year, 20-minute storm under 5 cfs for vegetated
lip and up to 30 cfs for rigid lip
|
D.
When BMP Is To Be Installed. Immediately after rough grading —
concurrent with diversion devices prior to completion of filter strips
downstream.
E.
Installation/Construction Procedures.
1.
Excavate to length, width, depth and slopes specified on plan.
2.
For rigid lip, excavate and stabilize a level area for timber
and gravel. Fill remaining excavated area behind timber with gravel.
3.
Seed and net or hydroseed "channel" area of spreader.
4.
For vegetated lip, staple erosion control blanket to protect
lip.
5.
Stabilize outfall area as depicted on plan.
6.
Install lathe or post at each end and center of spreader. Mark
maximum allowable sediment depth at one-half (1/2) the depth of the
spreader.
G.
Site Conditions For Removal. Remove after upstream areas are stabilized
with vegetation subsequent to removal of diversion devices.
H.
Typical Detail. Drawing RM-7.
|
DRAWING RM-7 LEVEL SPREADER
 |
 |
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. Continuous horizontal grooves on the surface
of slopes designed to reduce runoff velocity, increase infiltration,
reduce erosion and trap sediment. Roughening can also be used when
other methods of erosion/siltation control are not immediately available.
In this case surface roughening should be supplemented with other
BMPs as soon as possible.
B.
Where BMP Is To Be Installed. At the top of and at intermediate points
along disturbed slopes to disrupt low-volume, concentrated flows and/or
at the base of disturbed slopes to slow water runoff and capture sediment
laden runoff.
C.
Conditions For Effective Use Of BMP.
|
Type of flow:
|
Sheet flow
|
|
Contributing area:
|
Unlimited on slopes <10%
|
|
Slopes >10% require additional BMPs (such as diversion channel)
|
D.
When BMP Is To Be Installed. Immediately after rough grading prior
to seeding or mulching.
E.
Installation/Construction Procedures.
1.
Using light weight machinery, such as tractors with a harrow,
disk or box grader attachment, drag surface to create series of grooves
and ridges perpendicular to water flow.
2.
Light weight, track driven equipment, such as a skid-steer,
can be used to create the grooves; however, travel direction up and
down the slope is required.
G.
Site Conditions For Removal. The slope should be reworked to the
design grades immediately prior to final stabilization. In some cases,
such as seeding the area, the roughened area could be left as is.
H.
Typical Details. Drawing RM-8.
|
DRAWING RM-8 SURFACE ROUGHENING
 |
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. A flexible tubing or rigid conduit extending
from the top to the bottom of a cut or fill slope designed to protect
exposed slopes from upstream runoff. Slope drains typically extend
beyond the toe of slope to a stable area or outlet.
B.
Where BMP Is To Be Installed. Typically installed on long slopes
where runoff cannot easily be directed to the ends of a section of
cut or fill.
C.
Conditions For Effective Use Of BMP.
|
Type of flow:
|
Sheet flow and concentrated flow
|
|
Contributing area:
|
Maximum 5 acres per slope drain; pipe sized for 15-year, 20-minute
storm.
|
D.
When BMP Is To Be Installed. Concurrently with diversion devices
and at the end of each workday for slopes ten (10) feet or more in
height.
E.
Installation/Construction Procedures. Temporary slope drains must
be installed and maintained properly because failure will usually
result in severe erosion of the slope. Other points of concern are
failure from overtopping due to inadequate pipe inlet capacity or
blockage and lack of maintenance of the upstream diversion device
capacity.
1.
Install slope drain down the slope, extending beyond toe of
slope.
2.
Install flared end or t-section at pipe inlet. Section should
be well entrenched and stable so water can enter freely.
3.
Compact fill over and around pipe in area of diversion device.
4.
Ensure that all pipe connections are secure and water-tight.
5.
Securely anchor the exposed section of the drain with stakes.
6.
Install flared end section at pipe outlet — discharge
into a sediment trap or other stabilized outlet.
G.
Site Conditions For Removal. Remove concurrently with upstream diversion
device; immediately prior to permanent vegetation of slope.
H.
Typical Details. Drawing RM-9.
|
DRAWING RM-9 TEMPORARY SLOPE DRAIN
 |
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. A wide belt of vegetation running along a contour
designed to provide infiltration, intercept sediment and other pollutants
and reduce stormwater flow and velocity. Vegetation may be in the
form of natural wooded strip or proposed mix of erosion-resistant
plants that form a dense mat and effectively bind the soil.
B.
Where BMP Is To Be Installed. Adjacent to low or medium density residential
areas gently sloping ground (less than fifteen percent (15%)).
C.
Conditions For Effective Use Of BMP.
|
Type of flow:
|
Overland sheet flow only — cannot treat high velocity
flows
|
|
Contributing area:
|
Maximum of 5 acres, with less than 15% slope
|
D.
When BMP Is To Be Installed. Immediately after rough grading to trap
sediment during construction and/or immediately after final grading
as a permanent measure to control surface runoff.
E.
Installation/Construction Procedures.
1.
Fence off any undisturbed wooded strips to be preserved. No
activity, including parking vehicles or equipment and storing, clearing,
grubbing or construction debris, shall be permitted in the wooded
strip.
2.
If a grass filter strip is constructed, it must be completed
and vegetated before construction in the impervious area is started.
a.
Clear and grub the filter strip area.
b.
If the adjacent area does not have a level edge, install a level
spreader to distribute runoff evenly. See level spreader BMP for information.
c.
Fertilize and vegetate strip with erosion-resistant plants that
form a dense mat and effectively bind the soil, eg., crown vetch,
sod or seed and mulch.
F.
O&M Procedures.
1.
Inspect at least every week and after every storm during construction
and annually thereafter.
2.
Fill and compact eroded areas and reseed, mulch and fertilize
or establish other vegetation in the affected areas.
3.
After improvements are complete, regrade and reseed the top
edge of the filter strip to remove sediment trapped during construction
and prolong the effective use of the filter strip.
4.
Apply a complete fertilizer annually until the desired density
of vegetation is obtained. Thereafter, apply fertilizer in accordance
with the soil test recommendations.
5.
Protect new plantings from wildlife.
6.
Mow grass strips to a height of six (6) to twelve (12) inches
two (2) to three (3) times a year to suppress weeds and woody vegetation
unless natural, woody vegetation is planned.
7.
Repair foot paths and traffic ruts.
G.
Site Conditions For Removal. Not applicable.
H.
Typical Detail. Drawing SC-1.
|
DRAWING SC-1 FILTER STRIP
 |
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. A temporary sediment control barrier consisting
of a short concrete block wall supporting gravel filter media around
a grated inlet designed to prevent sediment from entering the storm
sewer. Shallow temporary ponding during and after rainfall should
be expected.
B.
Where BMP Is To Be Installed. At inlets where heavy flows are expected
and an overflow capacity is necessary to prevent excessive ponding
around the structure.
C.
Conditions For Effective Use Of BMP.
|
Type of flow:
|
Sheet flow and concentrated flow
|
|
Contributing area:
|
Maximum of 1 acre
|
D.
When BMP Is To Be Installed. Immediately after placement of inlet.
E.
Installation/Construction Procedures.
1.
Backfill, compact and uniformly grade area around inlet.
2.
Install first row of concrete blocks adjacent to the inlet sill,
placing one (1) block on its side on each side of inlet. The blocks
are placed against the sill for lateral support and to avoid washouts
when overflows occur.
3.
If needed for lateral support, install two (2) by four (4) lumber
through vertical block openings.
4.
Fill vertical block openings with gravel for stability.
5.
Place second row of block offsetting one-half (1/2) block from
the first row in a brick-like pattern.
6.
Fill vertical block openings with gravel.
7.
Anchor wire screen over horizontal block openings to support
gravel.
8.
Place gravel around the blocks.
G.
Site Conditions For Removal. Remove after contributing drainage areas
have been adequately stabilized. Restore area to grade and vegetate.
H.
Typical Detail. Drawing SC-2.
|
DRAWING SC-2 INLET PROTECTION — BLOCK AND GRAVEL
 |
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. A woven fabric barrier braced around an area
inlet designed to prevent sediment from entering the storm sewer.
Shallow temporary ponding during and after rainfall should be expected.
B.
Where BMP Is To Be Installed. At inlets designed to drain a small
gently sloping area with maximum grade of five percent (5%). Overflow
capacity is limited on standard area inlets.
C.
Conditions For Effective Use Of BMP.
|
Type of flow:
|
Shallow sheet flow
|
|
Contributing area:
|
Maximum of 2 cfs flowing to inlet
|
D.
When BMP Is To Be Installed. Immediately after placement of inlet.
E.
Installation/Construction Procedures.
1.
Backfill, compact and uniformly grade area around inlet.
2.
Construct downstream berm, if required. Rock bags or sand bags
may be used to construct berm.
3.
Drive posts or wood frame close to inlet sill so over flow will
fall directly in the structure and not on unprotected soil.
4.
Dig trench around inlet for fabric to be buried.
5.
Cut required length of fabric from one (1) roll to eliminate
joints. Fasten fabric tightly around posts/frame to enhance stability.
6.
Backfill and compact trench.
G.
Site Conditions For Removal. Remove after contributing drainage areas
have been adequately stabilized. Restore area to grade and vegetate.
H.
Typical Detail. Drawing SC-3.
|
DRAWING SC-3 INLET PROTECTION — FABRIC DROP
 |
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. An open graded gravel, wire mesh and woven
fabric filter barrier installed along the throat of a curb inlet designed
to prevent sediment from entering the storm sewer. The barrier is
supported by a wooden frame to provide stability and overflow capacity.
B.
Where BMP Is To Be Installed. Typically installed on pavement with
slopes less than two percent (2%) and flows are high.
C.
Conditions For Effective Use Of BMP.
|
Type of flow:
|
Sheet flow and concentrated flow
|
|
Contributing area:
|
Maximum of 2 acres due to reduction in inlet capacity
|
D.
When BMP Is To Be Installed. One (1) day after pavement is placed.
E.
Installation/Construction Procedures.
F.
O&M Procedures.
1.
Inspect at least every week and after every storm.
2.
Remove sediment accumulation once it is within three (3) inches
of the top of the inlet stone.
3.
Remove trash accumulation at inlet.
4.
Reposition/replace elements to original configuration as needed.
5.
Repair inadequate anchoring of frame or fastening of mesh.
G.
Site Conditions For Removal. Remove after contributing drainage areas
have been adequately stabilized.
H.
Typical Detail. Drawing SC-4.
|
DRAWING SC-4 INLET PROTECTION — GRAVEL AND WIRE
MESH
 |
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. A sod barrier installed around an area inlet
after the surrounding area has been stabilized. It is designed to
slow runoff velocities and remove sediments and other pollutants from
the runoff. This final inlet protection measure is an aesthetically
pleasing way to treat stormwater.
B.
Where BMP Is To Be Installed. Around the perimeter of an area inlet.
C.
Conditions For Effective Use Of BMP.
|
Type of flow:
|
Sheet flow and concentrated flow with velocities less than 5
fps
|
D.
When BMP Is To Be Installed. Near end of construction, after the
contributing watershed is stabilized with vegetation.
E.
Installation/Construction Procedures.
1.
Prepare and fertilize soil.
2.
Lay first row of sod adjacent to inlet perpendicular to the
direction of flow. Butt subsequent rows tight against previous rows
with strips staggered in brick-like pattern for a distance of at least
four (4) feet in each direction. Fill minor gaps with good soil and
roll entire surface to ensure surface contact.
3.
Stake, staple and/or net corners and centers of sod strips as
required.
4.
Water immediately after installation — enough to soak
four (4) inches into soil without causing runoff.
F.
O&M Procedures.
1.
Water sod daily for three (3) weeks — enough to soak four
(4) inches into soil without causing runoff.
2.
Inspect sod at least every week and after every storm.
3.
Reposition areas of sod that have moved.
4.
Remove sediment accumulation on sod once it extends within eighteen
(18) inches of inlet — replace sod if necessary.
5.
Repair any eroded areas, replace sod and stabilize as needed.
6.
Do not mow until three (3) inches of new growth occurs. During
the first four (4) months do not mow more than one-third (1/3) the
grass height.
G.
Site Conditions For Removal. Not applicable.
H.
Typical Detail. Drawing SC-5.
|
DRAWING SC-5 INLET PROTECTION — SOD FILTER
 |
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. A temporary settling pond designed to slowly
release runoff, detaining it long enough to allow most of the sediment
to settle out. Sediment basins cannot trap all sediment that enters.
Basins should be used in conjunction with additional BMPs, such as
temporary seeding, to reduce the total amount of sediment washing
into them. Sediment basins may also be designed to be converted to
permanent stormwater detention basins after site construction has
been completed.
B.
Where BMP Is To Be Installed. Should be located as close to the sediment
source as possible. A sediment basin should not be used in areas of
continuously running water (live streams) nor areas where failure
of the embankment will result in loss of life, damage to homes or
structures, or prevent the use of roadways or utilities.
C.
Conditions For Effective Use Of BMP.
|
Type of flow:
|
Sheet flow and concentrated flow
|
|
Contributing area:
|
Maximum ten (10) acres, as secondary or tertiary BMP
|
|
Basin volume:
|
Volume of fifteen-year, twenty-minute storm plus silt load of
one thousand eight hundred (1,800) cf per acre below top of riser
|
|
Surface area to volume ratio:
|
Minimum of 25:1
|
|
Length to width ratio:
|
Minimum of 5:1; can be reduced with use of flocculants
|
|
Runoff entry:
|
Maximize distance from outlet to provide maximum retention time;
minimum of twenty (20) feet
|
|
If needed, install porous baffles to partition the basin into
two (2) to three (3) cells and increase travel distance
| |
|
Outlet pipe:
|
Sized for 15-year, 20-minute storm when being converted to permanent
detention facility
|
D.
When BMP Is To Be Installed. Prior to disturbance of natural vegetation.
E.
Installation/Construction Procedures.
1.
Excavate to length, width, depth and slopes specified on plan.
2.
Place and compact fill to construct dam to elevation at least
one (1) foot about crown of outlet pipe.
3.
Install outlet pipe and compact clayey soil around pipe using
hand tampers.
4.
Install the perforated riser pipe, wrap with fabric and surround
with uniformly graded gravel.
5.
Install BMP at downstream end of outlet pipe.
6.
Complete installation of dam to an elevation ten percent (10%)
above design height to allow for settling.
7.
Grade and stabilize spillway.
8.
Install lathe or post near outlet of basin. Mark maximum allowable
sediment depth as designed.
F.
O&M Procedures.
1.
Inspect at least every week and after every storm.
2.
Remove trash accumulation at outlet.
3.
Remove sediment accumulations once sediment reaches design depth,
as indicated on monitoring posts.
4.
Repair and revegetate any erosion damage on spillway.
5.
Repair settlement, cracking, piping holes, seepage at embankment.
6.
Replace gravel around riser if basin does not drain properly.
G.
Site Conditions For Removal. Remove after upstream areas are stabilized
with vegetation. Regrade as appropriate and vegetate immediately.
H.
Typical Detail. Drawing SC-6.
|
DRAWING SC-6 SEDIMENT BASIN
 |
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. A temporary small area of impoundment designed
to trap water and allow sediment to settle out. A trap usually consists
of an excavated area with a dewatering pipe and spillway outlet stabilized
with fabric and rip-rap. Due to short retention periods, sediment
traps do not typically remove fine particles such as silts and clays.
B.
Where BMP Is To Be Installed. Commonly used at the outlets of BMPs
such as stormwater diversion devices, channels, temporary slope drains,
construction entrances, vehicle wash areas.
C.
Conditions For Effective Use Of BMP.
|
Type of flow:
|
Sheet flow and concentrated flow
|
|
Contributing area:
|
Maximum 5 acres
|
|
Basin volume:
|
Silt load of 1,800 cf per acre
|
|
Length to width ratio.
|
5:1 minimum; can be reduced with use of flocculants
|
D.
When BMP Is To Be Installed. Prior to disturbance of natural vegetation.
E.
Installation/Construction Procedures.
1.
Excavate to length, width, depth and slopes specified on plan.
2.
Install dewatering pipe.
3.
Place and compact fill to construct embankment and spillway.
4.
Place fabric over dewatering pipe and embankment.
5.
Install rip-rap on embankment and gravel over dewatering pipe.
6.
Install lathe or post at each end of basin and at twenty (20)
foot intervals. Mark maximum allowable sediment depth as designed.
F.
O&M Procedures.
1.
Inspect at least every week and after every storm.
2.
Remove trash accumulation.
3.
Remove sediment accumulations once sediment reaches design depth,
as indicated on monitoring posts.
4.
Repair and revegetate any erosion damage.
5.
Repair settlement, cracking, piping holes or seepage at embankment.
G.
Site Conditions For Removal. Remove after upstream areas are stabilized
with vegetation. Regrade as appropriate and vegetate immediately.
H.
Typical Details. Drawings:
1.
SC-7.1 Sediment Trap. For use in open areas.
2.
SC-7.2 Sediment Trap. Single chamber for use in line with swales
and/or channels.
3.
SC-7.3 Sediment Trap. Double chamber for use in line with swales
and/or channels.
|
DRAWING SC-7.1 SEDIMENT TRAP
 |
|
DRAWING SC-7.2 SEDIMENT TRAP — SINGLE CHAMBER
 |
|
DRAWING SC-7.3 SEDIMENT TRAP — DOUBLE CHAMBER
 |
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. A fence constructed of woven filter fabric
and wire mesh stretched between posts and entrenched in the ground
designed to pond stormwater runoff and cause sediment to settle out.
B.
Where BMP Is To Be Installed. Installed along slopes, at base of
slopes and around perimeter of site as final barrier to sediment being
carried off-site. Spacing of fence along slopes is relative to slope.
C.
Conditions For Effective Use Of BMP.
|
Type of flow:
|
Sheet flow only
|
|
Contributing slope length:
|
30 foot maximum for 3:1 slopes
|
|
50 foot maximum for slopes between 3:1 and 10:1
| |
|
100 foot maximum for slopes under 10%
|
D.
When BMP Is To Be Installed. Prior to disturbance of natural vegetation
and at intervals during construction of fill slopes.
E.
Installation/Construction Procedures.
1.
Drive post for fence line.
2.
Dig trench to required dimensions in front of posts for fabric
burial.
3.
Attach wire mesh to posts.
4.
Attach fabric to posts, allowing required length below ground
level to run fabric along bottom of trench.
5.
Backfill and compact soil in trench to protect and anchor fabric.
F.
O&M Procedures.
1.
Inspect at least every week and after every storm.
2.
Remove sediment buildup deeper than one-half (1/2) the fence
height or twelve (12) inches, whichever is less.
3.
Replace torn or clogged fabric; repair loose fabric.
4.
Repair unstable or broken posts.
5.
Stabilize any areas susceptible to undermining.
6.
Extend fence or add additional row(s) of fence if necessary
to provide adequate protection.
G.
Site Conditions For Removal. After permanent vegetation of slope
is established, remove fence, regrade trench area and vegetate.
H.
Typical Detail. Drawing SC-8.
|
DRAWING SC-8 SILT FENCE
 |
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. A stabilized entrance to a construction site
designed to minimize the amount of sediment tracked from the site
on vehicles and equipment. Stabilization generally consists of aggregate
over fabric. Mud and sediment fall off of tires as they travel along
the stabilized entrance; however, additional measures in the form
of a washdown area should also be included on-site. The stabilized
entrance also distributes the axle load of vehicles over a larger
area, thereby mitigating the rutting impact vehicles normally have
on unpaved areas.
B.
Where BMP Is To Be Installed. At locations where it is safe for construction
vehicles and equipment to access existing streets, preferably at location
of future streets or drives.
C.
Conditions For Effective Use Of BMP.
|
Type of flow:
|
Drainage: ditches or pipes if needed, sized for 16-year, 20-minute
storm;
|
|
Contributing slope length:
|
HGL six (6) inches below surface of entrance.
|
D.
When BMP To Be Installed. First order of work, along with washdown
area, prior to vehicles or equipment accessing unpaved areas.
E.
Installation/Construction Procedures.
1.
Grade and compact area of construction entrance.
2.
Install culvert under entrance if needed to maintain positive
drainage.
3.
Place fabric and cover with aggregate, forming diversion across
entrance, if needed, to direct runoff away from roadway.
4.
See washdown station BMP for additional steps.
G.
Site Conditions For Removal. Remove when vehicles and equipment will
no longer access unpaved areas.
H.
Typical Detail. Drawing TC-1.
|
DRAWING TC-1 CONSTRUCTION ENTRANCE
 |
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. A stabilized pad designed to provide off-street
parking for construction-related vehicles, eliminate parking on non-surfaced
areas and minimize the amount of sediment tracked from the site. Stabilization
generally consists of aggregate over woven fabric. The stabilized
pad also distributes the axle load of vehicles over a larger area,
thereby mitigating the rutting impact vehicles normally have on unpaved
areas.
B.
Where BMP Is To Be Installed. At locations close to related work
zones that have access along continuous paved stabilized surfaces.
Parking may be distributed in clusters and/or relocated with different
phases of construction.
C.
Conditions For Effective Use Of BMP.
|
Drainage:
|
Ditches or pipes, if needed, sized for 15-year, 20-minute storm;
HGL below parking surface
|
|
Aggregate size:
|
2 to 3 inch washed sto
|
|
Pad design:
|
Minimum of 12 inches thick and sized to handle anticipated number
of employee and visitor vehicles. Plans shall provide provisions for
relocation and resizing of parking area(s) as construction phasing
requires. See table below for minimum requirements
|
|
Construction Phase
|
Minimum Number Of Parking Spaces
|
|---|---|
|
Rough grading
|
3
|
|
Sewer and street construction
|
10
|
|
Residential home construction
|
10**
|
|
Commercial building construction
|
20
|
|
* Parking space shall be a minimum of nineteen (19) feet long
and nine (9) feet wide.
| |
|
** If multiple home builders involved, additional spaces required
| |
|
Filter fabric: Woven fabric — Mirafi 600X or equal
| |
D.
When BMP Is To Be Installed. Immediately after or concurrently with
installation of construction entrance and washdown station.
F.
O&M Procedures.
1.
Inform drivers of inappropriately parked vehicles that they
need to be moved.
2.
If necessary to ensure compliance on an ongoing basis, contact
employers of violators.
3.
Install no parking signage in areas where vehicles are being
parked inappropriately.
4.
Remove sediment and clods of dirt continuously.
5.
Repair settled areas.
6.
Replace rock if necessary to maintain clean surface.
G.
Site Conditions For Removal. Remove/relocate when vehicles can legally
park on paved areas without impeding non-construction related traffic.
H.
Typical Detail. Not applicable.
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. A stabilized pathway providing vehicular access
to a remote construction area designed to reduce rutting, tracking
of mud in wet weather and creation of dust in dry weather. The "roadway"
can be constructed of aggregate over fabric, asphaltic concrete or
Portland cement concrete based on the longevity of the project, required
performance and site conditions. Roadways should follow the natural
terrain to the extent possible.
B.
Where BMP Is To Be Installed. On long travel paths on unpaved areas,
adjacent to bodies of water and in areas where poor soil is encountered.
C.
Conditions For Effective Use Of BMP.
1.
Drainage. Road ditches or pipes, if needed, sized for 15-year,
20-minute storm; HGL six (6) inches below surface of road.
D.
When BMP Is To Be Installed. First order of work, prior to vehicles
or equipment accessing remote areas.
G.
Site Conditions For Removal. Remove when vehicles and equipment will
no longer access remote areas, regrade area and vegetate.
H.
Typical Detail. Drawing TC-3.
|
DRAWING TC-3 CONSTRUCTION ROAD
 |
[Ord. No. 17-0244, 4-24-2017]
A.
Physical Description. An area located at construction entrances designed
to wash sediment from the tires and undercarriage of exiting vehicles
and prevent sediment from being tracked onto exiting roadways.
B.
Where BMP Is To Be Installed. Across or immediately adjacent to exit
paths from unpaved construction sites.
C.
Conditions For Effective Use Of BMP.
1.
Drainage. Downstream BMP sized to treat dirty runoff from washdown
station.
D.
When BMP Is To Be Installed. First order of work, along with construction
entrance, prior to vehicles or equipment accessing unpaved areas.
E.
Installation/Construction Procedures.
1.
Grade and compact area for drainage under washdown pad.
2.
Install steel-ribbed plate on frame or other support to allow
a two (2) inch drain space.
3.
Grade and vegetate downstream BMP (v-ditch shown on detail).
4.
Install water supply and hose.
5.
Post sign in advance of station indicating that all exiting
vehicles and equipment must use station prior to exiting site.
G.
Site Conditions For Removal. Remove when vehicles and equipment will
no longer access unpaved areas.
H.
Typical Detail. Drawing TC-4.
|
DRAWING TC-4 WASHDOWN STATION
 |
