Course Highlights

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• Course Highlights
• Introduction
• Planning for Erosion and Sediment Control
• Selection of BMPs For Erosion Control
• Selection of BMPs For Sediment Control
• Field Demonstration of BMPs

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SEDIMENT CONTROL BMPs

• SC-1 SILT FENCE
• SC-2 Sediment/Desilting Basin
• SC-3 Sediment Trap
• SC-4 CHECK DAMS
• SC-5 FIBER ROLLS
• SC-6 GRAVEL BAG BERM
• SC-8 SAND BAG BARRIER
• SC-9 STRAW BALE BARRIER
• SC-10 STORM DRAIN INLET PROTECTION

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TEMPORARY SEDIMENT CONTROLS

• These practices can consist of
• temporary linear sediment barriers (silt fences
  etc.),
• fiber rolls, gravel bag berms, or
• check dams to break up slope length or flow
• or temporary sediment/desilting basin or sediment
  trap.
• Sediment control generally involves intercepting
  sediment laden runoff, slow the flow, and allow
  the suspended sediment particles to drop out of
  suspension.

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SEDIMENT CONTROL BMPs

• SC-1 Silt Fence
• Silt fences allow sediment to settle from runoff.

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SC-1 SILT FENCE
Permeable fabric designed to intercept and slow
flow of sediment-laden sheet flow runoff

• Material Requirements
• Silt fence shall be woven polypropylene fabric
• Minimum width of 900 mm (36 inches)
• The fabric shall conform to the requirements in
  ASTM (American Society for Testing and Materials)
  designation D4632 and have an integral
  reinforcement layer

• The permitivity of the fabric shall be between
  0.1 sec -1 and 0.15 -1 in conformance with ASTM
  designation D4491

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SC-1 SILT FENCE

• Silt fence looses its permeability when it comes
  in contact with sediment-laden runoff
• Runoff is ponded

The geotextile is no longer passing 20 gal/min.
The forces exerted are great - proper staking and
keying-in of silt fence is critical
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SC-1 SILT FENCE

• Stakes Requirements
• Wood stakes shall be commercial quality lumber
• Stake dimensions 50 x 50 mm (2 x 2 inches) by
  1200 mm (48 inches) in length
• Stakes shall be free from decay, splits or cracks
  longer than the thickness of the stakes
• 2.5 m (8 ft) maximum stake spacing

• Bar reinforcement may be used, greater than or
  equal to (4) with end protection.

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SC-1 SILT FENCE

• Design and layout
• Maximum length of slope draining to any point
  shall be 61 m (200 ft)
• Slope of area draining to the silt fence shall be
  less than 11 VH
• For slopes steeper than 12 that contain large
  numbers of rocks or dirt clods that tend to
  dislodge additional protection may be necessary

61 m (200 ft) max
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SC-1 SILT FENCE
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SC-1 SILT FENCE

• Key-in bottom of silt fence a minimum of 300 mm
  (12 inches)

• Construct silt fence with a set-back of at least
  1 m (3 ft) from the toe of the slope

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SC-1 SILT FENCE

• Installation Requirements
• Reach of silt fence shall not be longer than 150
  m (490 ft)
• Construct each reach so that the base elevation
  does not exceed 1/3 the height of the
  barrierexample (1/3 of 24 8)

lt 150 m (490 ft)
Base elev. Not to Exceed 8
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SC-1 SILT FENCE
Improper silt fence application can cause erosion
Incorrect application across concentrated flow
Incorrect - up and down slopes
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SC-1 SILT FENCE

• 2000 to 2003 Manual Changes
• Added limitations for
• Not implementing on slope subject to creeping,
  slumping and landslides
• Not implementing in areas of concentrated flow
• Do not use silt fences for diverting flow
• Added specification for silt fence to meet
  Standard Specification Section 6-1.07
• Added specification to key silt fence a minimum
  of 300 mm (12)

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SC-2 Sediment/Desilting Basins

• DSAs between 2 and 4 ha (5 to 10 acres)
• 100 m3/ha (1,430 ft3/acre) storage
• Length ? 2x Width
• Depth 1 to 1.5 m (3 to 5 ft)
• Features to accommodate bypass or overflows
• Drain within 72 hours

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SC-2 Sediment/Desilting Basins

• A major obstacle to desilting basin effectiveness
  is the outlet design

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SC-2 Sediment/Desilting Basins

• A desilting basin must have an emergency spillway
  for overflow

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SC-3 Sediment Trap

• Size limited by availability of right-of-way
• Not appropriate for drainage areas greater than 2
  ha (5 acres)
• Sediment storage 65 m3/ha (929 ft3/acre)
• Length ? 3x Width
• Depth 1 to 1.5 m (3 to 5 ft)
• If captured runoff has not completely infiltrated
  within 72 hours dewater trap
• Safety fencing may be required

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SEDIMENT CONTROL BMPs

• SC-4 Check Dams
• Are small devices constructed of rock, gravel
  bags, fiber roll, of other proprietary devices
  placed across natural or man-made channels or
  ditches

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SC-4 CHECK DAMS

• Material Requirements
• Bags shall be either polypropylene, polyethylene,
  or polyamide woven fabric
• Minimum unit weight of 135 g/m2 (four ounces per
  square yard)
• Burst strength exceeding 2,070 kPa (300 psi) in
  conformance with ASTM designation D3786
• Ultraviolet stability exceeding 70 in
  conformance with ASTM designation D4355

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SC-4 CHECK DAMS

• Bag size Requirements
• Each gravel-filled bag shall have a length of 450
  mm (18 inches), width of 300 mm (12 inches),
  thickness of 75 mm (3 inches), and mass of
  approximately 15 kg (33 lbs)
• Alternate bags sizes need approval by the
  Resident Engineer
• Fill material
• Fill material shall be between 10 mm and 20 mm
  (0.4 and 0.8 inches) in diameter
• Be free from clay balls, organic matter and other
  deleterious material
• Filled bag shall be between 13 kg and 22 kg (28
  and 48 lbs) in mass

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SC-4 CHECK DAMS

• Installation Requirements
• Limit area draining to check dams to 4 ha (10 ac)
  or less
• Install along a level contour
• Tightly abut bag and stack in a pyramid fashion
• Place at a distance and height to allow small
  pools to form behind them
• Install the first check dam 5 m (16 ft) from the
  outfall
• Space bags based on slope gradient and soil type
• Gravel bags shall not be stacked higher than 1 m
  (3.2 ft)

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SC-4 CHECK DAMS

• 2000 to 2003 Manual Changes
• Gravel bags, fiber roll and other proprietary
  products add as construction material
• Fiber rolls need RE or NPDES Coordinators
  approval
• Gravel bags may be used with new specifications
• Gravel diameter between 10-20 mm (0.4-0.8 inch)
• Bag size and material added
• Installation specification for stacking

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SEDIMENT CONTROL BMPs

• SC-Fiber Rolls
• Consist of wood excelsior, rice or wheat straw,
  or coconut fibers that are rolled and bound into
  a tight tubular roll and placed on slopes to
  intercept runoff

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SC-5 FIBER ROLLS

• Material Requirements
• Fiber roll shall be either (1) prefabricated
  rolls or (2) rolled tubes of erosion control
  blankets
• For field rolled fiber rolls roll into a minimum
  of 200 mm (8 in) diameter, and bond every 1.2 m
  (4 ft) along the length of the roll

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SC-5 FIBER ROLLS

• Installation Requirements
• For breaking-up slope length fiber roll spacing
  is based on slope inclination
• 14 or flatter spacing shall be placed 6.0 m
  (20 ft) apart
• 14 to 12 spacing shall be 4.5 m (15 ft) apart
• 12 or greater spacing shall be 3.0 m (10 ft)
  apart
• Place fiber rolls into a 50 to 100 mm (2 to 4
  inches) trench

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SC-5 Fiber Rolls

• Stake or tie fiber rolls into place
• Tied fiber rolls staking is spaced at 600 mm (2
  ft) apart
• Stake spacing at 1.2 m (4 ft) apart

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SC-5 FIBER ROLLS

• Fiber rolls may be used for inlet protection if
  properly anchored

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SC-5 FIBER ROLLS

• 2000 to 2003 Manual Changes
• Fiber roll materials change
• Specifications that rolls be placed at grade
  breaks, toe and face of slopes
• Specifies that they can be used for drain inlet
  protection
• Specifies that they can be used as check dams
• Larger size may be needed at toes of slopes
• Restricts use on slopes subject to creep,
  slumping or landslides
• Spacing intervals on slopes reduced
• Overlapping of ends and new detail
• Maintenance features added with sediment build-up
  removal

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SEDIMENT CONTROL BMPs

• SC-6 Gravel Bag Berms
• Are woven fabric type of bags placed across
  slopes to intercept runoff, reduce its flow
  velocity, and release it as sheet flow

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SC-6 GRAVEL BAG BERMS

• Material (bags) Requirements
• Bags shall be either polypropylene, polyethylene,
  or polyamide woven fabric
• Minimum unit weight of 135 g/m2 (four ounces per
  square yard)
• Burst strength exceeding 2,070 kPa (300 psi) in
  conformance with ASTM designation D3786
• Ultraviolet stability exceeding 70 in
  conformance with ASTM designation D4355

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SC-6 GRAVEL BAG BERMS

• Bag size Requirements
• Each gravel-filled bag shall have a length of 450
  mm (18 inches), width of 300 mm (12 inches),
  thickness of 75 mm (3 inches), and mass of
  approximately 15 kg (33 lbs)
• Alternate bags sizes need approval by the
  Resident Engineer
• Fill material
• Fill material shall be between 10 mm and 20 mm
  (0.4 and 0.8 inches) in diameter
• Be free from clay balls, organic matter and other
  deleterious material
• Filled bag shall be between 13 kg and 22 kg (28
  and 48 lbs) in mass

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SC-6 GRAVEL BAG BERMS

• Installation requirements
• Install along a level contour
• Turn ends of bags up slope to prevent flow around
  ends
• Use in conjunction with temporary soil
  stabilization
• Construct barriers with a set-back of a least 1 m
  (3 ft) from toe of slope
• For concentrated flows stack bags using a
  pyramid approach, overlap upper joints from lower
  rows

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SC-6 GRAVEL BAG BERMS

• 2000 to 2003 Manual Changes
• Added language for application where flows are
  moderately concentrated
• Revised specifications for fill materials
• Burlap bags are no longer allowed
• Added application and installation for linear
  sediment control, on slopes, toe of slopes,
  stockpiles, concentrated flows and perimeter
  barriers
• Add Certification of Compliance per Standard
  Specs 6-1.07

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SEDIMENT CONTROL BMPs

• SC-8 Sandbag Barrier
• Are a woven fabric type of bag designed to
  intercept and slow flow of sediment-laden sheet
  flow runoff

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SC-8 SANDBAG BARRIER

• Material (bags) Requirements
• Bags shall be either polypropylene, polyethylene,
  or polyamide woven fabric
• Minimum unit weight of 135 g/m2 (four ounces per
  square yard)
• Burst strength exceeding 2,070 kPa (300 psi) in
  conformance with ASTM designation D3786
• Ultraviolet stability exceeding 70 in
  conformance with ASTM designation D4355

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SC-8 SANDBAG BARRIER

• Bag size Requirements
• Each gravel-filled bag shall have a length of 450
  mm (18 inches), width of 300 mm (12 inches),
  thickness of 75 mm (3 inches), and mass of
  approximately 15 kg (33 lbs)
• Alternate bags sizes need approval by the
  Resident Engineer
• Fill material
• All sandbag fill material shall be non-cohesive,
  Class 1 or Class2 permeable material free from
  clay and deleterious material
• Conform to section 68-1.025 of the Standard
  Specifications
• Fill Material is subject to approval of the RE

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SC-8 SANDBAG BARRIER

• Installation requirements
• Install along a level contour
• Turn ends of bags up slope to prevent flow around
  ends
• Use in conjunction with temporary soil
  stabilization
• Construct barriers with a set-back of a least 1 m
  (3 ft) from toe of slope

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SC-8 SANDBAG BARRIER

• 2000 to 2003 Manual Changes
• Burlap bags are no longer allowed
• Category changed from linear sediment removal
  to Linear sediment control

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SEDIMENT CONTROL BMPs

• SC-9 Straw Bale Barrier
• Are temporary linear sediment barriers consisting
  of straw bales, designed to intercept and slow
  sediment-laden sheet flow runoff

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SC-9 STRAW BALE BARRIER

• Material (bales) Requirements
• Material shall conform to the provisions in
  Standard Specifications Section 20-2.06 straw
• Straw shall be derived from wheat, rice, or
  barley
• The contractor shall furnish evidence that
  clearance has been obtained from the County
  Agriculture Commissioner, as required by law, if
  straw is obtained from outside the county

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SC-9 STRAW BALE BARRIER

• Straw Bale size Requirements
• Each bale shall be a minimum of 360 mm (14 in)
  wide, 450 mm (18 in) in height, 900 mm (36 in) in
  length and shall have a minimum mass of 23 kg (51
  lbs)
• Bales shall be composed entirely of vegetative
  matter, except binding material

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SC-9 STRAW BALE BARRIER

• Stakes
• Wood stakes shall be commercial quality lumber
• Stake dimensions 50 x 50 mm (2 x 2 inches) by
  1200 mm (48 inches) in length
• Stakes shall be free from decay, splits or cracks
  longer than the thickness of the stakes
• Bar reinforcement may be used, and its size shall
  equal to or greater than (4) and end protection
  is require

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SC-9 STRAW BALE BARRIER

• Installation Requirements
• Limit upstream drainage area to 0.3 ha/100 m
  (0.25 ac/100 ft)
• Limit length of slope draining to barrier to 30 m
  (100 ft)
• Slopes of 2100 (2) VH or flatter are preferred
• If slope exceeds 110 VH slope length must be
  less than 15 m (50 ft)
• Install along level contours
• Bales must be trenched in and tightly abutted
  together
• Construct barriers with a set-back of a least 1 m
  (3 ft) from toe of slope

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SC-9 STRAW BALE BARRIER
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SC-9 STRAW BALE BARRIER

• 2000 to 2003 Manual Changes
• Added limitations verbiage that bales can invite
  undesirable non-native plants and be an
  attractive animal food source
• Added option to allow use of 4 steel bars as
  stakes

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SEDIMENT CONTROL BMPs

• SC-10 Storm Drain Inlet Protection
• Device used at storm drain inlets to detain of
  filter sediment-laden runoff

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SC-10 INLET PROTECTION

• DI Protection Types
• Filter fabric fence
• Excavated drop inlet sediment trap
• Gravel bag
• Foam barrier and fiber rolls

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SC-10 INLET PROTECTION

• General requirements
• Requires adequate area for ponding without
  encroaching upon the traveled way
• Frequent maintenance is required
• Draining areas greater than 0.4 ha (1 ac) shall
  be routed to a sediment trapping device
• May require other methods of temporary protection
  to prevent sediment-laden storm water and
  non-storm water flow from entering inlets
• If high flows are expected use other sediment
  trapping devices in conjunction with inlet
  protection

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SC-10 INLET PROTECTION

• Type -1 Filter Fabric Fence
• Appropriate in open areas subject to sheet flows
• Flows should not exceed 0.014 m3/s (0.5 cfs)
• Do not place fabric underneath grate inlet

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SC-10 INLET PROTECTION

• Type-2 Excavated Drop Inlet Sediment Trap

• Appropriate where relatively high heavy flows are
  expected and over flow capacity is needed
• Size excavated trap to provide a minimum storage
  capacity of 130 m3/ha (11,340 ft3/ac) of drainage
  area

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SC-10 INLET PROTECTION

• Type-3 Gravel Bag
• Appropriate where flows exceed 0.014 m3/s (0.5
  cfs) and it is necessary to allow overtopping to
  prevent flooding
• Flows shall not overtop curb
• Construct in accordance with BMP SC-6
• In areas with high silts and clayey soils use
  additional media for protection

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SC-10 INLET PROTECTION

• Type-4 Foam Barriers and Fiber Rolls
• Not appropriate for locations where they can not
  be properly anchored
• Intended for use in areas around inlets are
  unpaved
• Requires RE or DSWC approval

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SC-10 INLET PROTECTION

• 2000 to 2003 Manual Changes
• Sandbags are no longer allowed (gravel bags)
• Added option of using foam barriers of fiber
  rolls if they can be properly anchored (RE/DCSWC
  approval)
• Type 1 - use of filter fabric fence added to spec
  when grade is established and erosion control
  seeding is installed or pending
• Type 2 excavated drop inlet specified in areas
  of exposed soils
• Type 3 gravel bag barriers are specified in
  areas of paved surfaces
• Added specification on removing built-up sediment
  from foam barriers and silt fences

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Questions ?