EROSION CONTROL WHAT IS AVAILABLE & HOW TO PROPERLY INSTALL IT Presented by : Patricia A. Daniel, CPESC Red River Hydro-Seeding, Inc. August 4, 2010 [email protected]
EROSION CONTROL WHAT IS IT ?
“Erosion Control is any practice that
protects the soil surface and prevents the soil particles from being detached by rainfall or wind.” John McCullah 2002
SEDIMENT CONTROL WHAT IS IT?
Sediment control is the practice used to keep sediment, (soil particles left unprotected from wind and rain), from leaving the site.
RUNOFF Runoff is the stormwater increased in volume and velocity during a rain event because vegetation has been removed. Examples:
Channels Ditches Slopes
BEST MANAGEMENT PRACTICES (BMP’S)
“Methods that have been determined to be the most effective, practical means of preventing or reducing pollution from a non-point source. “ °
SWPPP Stormwater Preventive Pollution Plan: A plan for storm water discharge that includes erosion control and sediment control prevention measures and controls.
EROSION CONTROL BMP’S
The most effective, efficient, and economical method of controlling erosion is to use: ¾
Established vegetation – buffers
Vegetation can reduce erosion by 90% Schedule dirt work for the driest parts of the year ¾ Stage dirt operations. ¾
EROSION CONTROL BMP’S
SURFACE ROUGHENING PERMANENT SEEDING TEMPORARY SEEDING MULCH COVER SOLID SOD EROSION CONTROL BLANKETS TRM’S (TURF REINFORCEMENT MATS)
SEDIMENT CONTROL BMP’S
Silt Fence Sand Bag Ditch Checks Hay Bale Ditch Checks Drop Inlet Protection Sediment Logs
RUNOFF CONTROL BMP’S
Grass Lined Channels Turf reinforcement mats and blankets Slope drains Waddles Sediment Logs
INSTALLING EROSION CONTROL BMP’S
Properly track a slope. “Tracking with machinery such as a dozer up and down the slope places grooves on the slope that allows a place for seed, fertilizer, and water to be trapped and also serves as a runoff control as it slow water going down the slope.
RE-ESTABLISHMENT OF VEGETATION:
Ph Soil testing is needed to apply lime at the correct rate. Always measure the area for correct application of seed, fertilizer, and lime.
METHODS OF SEEDING
Hydro-Seeding - Seed, fertilizer, lime can be applied in a slurry Broadcast Seeding- Seed, fertilizer, lime is spread with mechanical spreaders Hand Broadcast Seeding – Seed and fertilizer spread by hand
CHOOSE THE RIGHT SEEDS Temporary Seeds Examples: Warm Season:
Brown Top Millet 50# per Ac
Cool Season: Annual Rye Grass or Wheat or other Cereal Grass 100# per Ac AHTD Standard Spec
PERMANENT SEEDS Examples: WARM SEASON
BERMUDA GRASS COMMON - HULLED SEEED 5# Acre Bermuda Grass Common – Unhulled Seed 10# Acre Wildflower Mix 2.5# Acre
Examples: COOL SEASON Annual Rye Grass or Cereals (Wheat, Oats, )
Crimson Clover (Dixie)
Bermuda Grass Common unhulled Wildflower Mix
20# Acre 2.5# Acre AHTD Standard Spec
MULCH COVER FLAT AREAS TO 3:1 SLOPES HAY
4,000# per Acre
STRAW 4,000# per Acre Hydro-Mulch Paper ( As recommended by Mfr.) Hydro-Mulch Wood Fiber (As recommended by Mfr.) STEEPER THAN 3:1 Slopes Hydro-Mulch Wood Fiber Mulch Erosion Control Blankets 2:1 SLOPES AND STEEPER EROSION CONTROL BLANKETS/TRM’s Bonded Fiber Matrix
Install year around Prepare dirt as for seed bed Fertilize the area with approx. l# per l9sy Roll with a lawn roller or tamper Water thoroughly
EROSION CONTROL BLANKETS SLOPES Erosion Control blankets can be used on 2H:1V slopes - 1.5H:1V slopes. Always install according to manufacturers recommendation. Prepare the soil just as you would for seeding, grading and shaping the area. Be sure all clots , rocks, and other vegetation is removed. Lime, fertilize, seed and add all other amendments to the soil before the blanket is installed. Blankets need to fit snug to the ground . Trench in and staple according to manufacturers recommendations.
TURF REINFORCEMENT MATS TRM’S
Designed for Channels - Large flows of water Most of the TRM’s can replace concrete ( about 25% of the cost for concrete ) Can be used on slopes than exceed blanket capabilities Seed and Fertilizer is installed before TRM is installed (unless recommended after installation by Manufacturer)
INSTALLING SEDIMENT CONTROL BMP’’S Silt Fence Concentrated runoff can cause failure of the silt fence. Install silt fence with J-hooks which are smaller segments of silt fence that can hold and retain smaller quantities of run off.
J HOOKS Up hill turn should be in the Direction of water flow.
Sediment Should Pond Behind Silt fence
SILT FENCE WHAT IT IS NOT
It is not a filter fabric It is not for direct flow of water. Do not put it across the stream. Do not put is across a channel.
SILT FENCE WHAT IT IS AND WHAT IT DOES
It is designed for sheet flow Should be on the contour of a slope Toe of the slope Around stockpiles Any where it can hold and pond water It allows sediment to fall out of suspension be fore it leaves the area.
INSTALLING SILT FENCE
Be sure and install the fence with the stakes away from the flow of water. On the back side. When you finish installing silt fence turn the end uphill. Post should be driven into the ground __2’ min. The fabric must be keyed in at least 6” at the beginning and the end with the fabric trenched, sliced, or dug in at least 6”. Compact the dirt on both sides of the fence to prevent erosion.
SLICING TOMMY SILT MACHINE No compacting Needed after installation
HOW TO ATTACH TWO ROLLS TOGETHER
When attaching two rolls place the end of Second roll inside the end post of the first roll. Rotate both post l80 degrees in a clockwise direction to create a tight seal. Drive both post in the ground ___2’ . Key fabric in 6”.
Go behind the first roll of fabric installed about 3 LF and start the second roll of fabric.
FAILURE OF SILT FENCE Improper use of the silt fence Improper installation Improper maintenance Not enough silt fence used for the area of runoff.
MAINTENANCE OF SILT FENCE
Silt fence should be maintained when sediment is l/3 the height of the fence
Silt fence is torn or sagging
Silt fence has been damaged by equipment
Remove silt fence when vegetation has been established.
HAY BALE DITCH CHECKS
Hay bales should weight at least 50# each Should measure 30”, or longer Should be bound with wire, or poly string Install 2 stakes per bale 36” 1l/2 x l l/2 wood stakes
HOW TO INSTALL A HAY BALE DITCH CHECK Each hay bale should be keyed into the ground at least 4”. Drive in wooden stakes through each bale, one at an angle, so that it goes into the bale laid before it to ensure a tight fit. The stakes should be driven into the ground at least 18”. Maintenance should be done regularly to keep sediment removed from hay bales. Binding should be around the sides rather around the top and bottom to maintain the integrity of the hay bale.
SAND BAG DITCH CHECKS
Can be used in ditches with a more direct flow They can be stacked to meet the needs of the flow Sand bags can be filled with gravel for a filter bag. Bags should be filled to within 6” of top for proper tying. One Sand Bag should be removed from the middle and top to form a dam for water to flow over.
DROP INLET SEDIMENT BARRIERS
It is a barrier put around a drop inlet to prevent sediment from going into a storm drain.
They can be build of gravel and stone, sandbags filled with gravel, cinder blocks, or silt fence structures sediment logs
SEDIMENT LOGS Sediment logs can filter water Can be used as a continuous berm
Can be used in ditch bottoms Perimeter controls In place of rock ditch checks Replace silt fence Replace hay bale Replace sand bags Used in areas where water leaves and enters a project
SEDIMENT LOGS AS INLET PROTECTION
TRIANGULAR SILT FENCE DIKE
This product can replace rock filter dams, silt fence, hay bale ditch checks, and sandbag ditch checks. Can be used as a continuous berm They are reusable The have a protective apron on both sides
TRIANGULAR SILT FENCE
The purpose of a continuous berm is to divert and capture sheet runoff. They can be used at the perimeter of property to pond water until the sediment in suspension has had time to fall out of the water. They can be used as a filter if they are filled with aggregate and permeable filter fabric. Continuous Berms can replace straw ditch checks and silt fence. Some do require a machine to install.
RUNOFF BMP’S Grass Lines Channels.
Reduce erosion by slowing the water Best used in wide shallow drainage areas Used to look like a natural setting Must be installed after sediment traps are installed to insure sediment is not deposited on sod.
Primary use is on hillslopes to break up slope lengths and slow runoff.
May be placed across channels
Construction exits must be used by all entering and exiting the project site. They must be maintained regularly They may require a wash out area
INSTALLING A CONSTRUCTION EXIT
The exit should be long enough for at least 4-5 wheel rotations of the largest vehicle or equipment on site. A min of 50’. The pad should be at least 3-4” deep. Fabric installed under riprap 4-5” Landscape Riprap placed on top of fabric.
McCullah, J (2002). How to Put the Best Back into your Erosion Control BMP’s.(2002) Manual Environmental Protection Agency Epa.gov/OCEPAterms/bterms.html Arkansass Highways and Transportation Standard Specifications for Roadway and Bridges (2003) Little Rock, Ar Arkansas Highways and Transporations Construction Plans (2009),Little Rock, Ar American Excelsior Company Americanexclesior company.com/erosion control products/sediment logs. php Americanexcelsior company.com/erosion control products/waddles.php Acfenvironmental.com/PDFs/TriangularSiltDike/Bro-Triangular20%silt%20Dike.pdf International Erosion Control Association. Practical Approaches for Effective Erosion and Sediment Control – Manual
RESOURCES Caltran storm water quality handbooks section 6. (2003). Construction Site Best Management Practices Manual Stabilizied Construction Entrances/Exit Tc-1, TC-3 Texas Department of Transportation www.dot.state.us/business/specifications.htm Hildebrand, J (2010). ELG’s and Construction Industry: What does this new rule mean to my project (2010) Webinar