Temporary Seeding and Mulching

Temporary seeding and mulching is, without a doubt, the most cost-effective erosion and sediment control measure.  Not only is it the most effective way to treat large areas of unstable soil, it can be used in almost every possible situation.   Stream banks, drainage ways, ditches, road cuts, utility right-of-ways, detention basins, new construction, and timber harvest sites can all be treated with temporary seeding and straw mulching. 

Temporary seeding and mulching can be applied at any time of the year and still be effective.  As long as the ground is not covered with snow, the straw mulching can stabilize the soil until the root systems of the grass can become established.   Hydroseeding has quickest seed germination rates, but seed accompanied with straw mulching provides both instant and long term erosion control. Further information about temporary seeding can be found in the latest edition of the Ohio Department of Natural Resource’s Rainwater and Land Development Manual.

Lake County SWCD Temporary Seeding Technical Bulletin #03-001

Temporary seeding species selection

Click for larger image

Sublot Seeding

Sublot seeding and mulching is an essential element in erosion control.  It prevents rain droplets form detaching soil particles from exposed areas as well as retaining the necessary moisture needed for the germination and growth of seeded areas of a disturbed soil site.  Once wet or packed under snow, straw mulch also locks itself into the soil, thus stabilizing the surface layer and preventing soil detachment from initiating.

Straw is the most common and cost effective mulch and is highly recommended for all sites.  In areas that have steep grades or are prone to high winds and/or concentrated surface water flows, stapled fiber matting and meshes should be used, as they are less prone to blow or wash away.  Wood chips are another cost effective alternative which, when used in conjunction with a silt fence, can be very effective. Wood chips are often readily available on construction sites.

Mulching over the temporary seeding of a sublot shall extend the length of curb at a minimum width of 30 feet from the curb.  Mulching shall remain on site from the time the initial clearing is done on the site to the completion of the landscaping by the homeowner. Note: 1 straw bale per 10 feet of curb is the minimum amount of mulching for a single lot to adequately cover the 30-foot wide temporary seeding area. Example: for 100’ of lot frontage, a minimum of 10 bales is required. Further information about sublot seeding and mulching can be found in the latest edition of the Ohio Department of Natural Resource’s Rainwater and Land Development Manual.

Lake County SWCD Temporary Seeding Technical Bulletin #03-001

 Lake County SWCD Erosion Control On Your Lot Technical Bulletin #98-003

Temporary seeding species selection

Click for larger image

Construction Entrance

Construction entrances for ingress/egress to localized soil disturbances are an essential component of erosion control on all residential and commercial construction sites. They are necessary to keep tires clean and prevent sediment from being tracked onto the roadway.  They are constructed of at least a six-inch bed of stone or clean recycled concrete spread out on a geotextile fabric that prevents the stone from sinking into the soil over the course of their use.

Lake County SWCD Construction Entrance Technical Bulletin #03-002

Construction Entrance Specifications

Click for larger image

Inlet Protection

Storm water inlet protection can be one of the most effective sediment control devices if they are installed properly.  Storm sewer catch basins and yard drains are at high risk to receive sediment during construction.

All catch basins and yard drains should be fitted with a staked-in silt fence box inlet protection.  The reinforced silt fencing should remain in place until all areas that drain to the catch basin or yard drain are stabilized with permanent vegetation. 

The silt fencing around these inlets is intended to pond or pool water temporarily so that sediment drops out of the storm water before it enters the storm sewer system. Regular removal of sediment and repair to the silt fence structure is critical to the effectiveness of this type of BMP. Further information about inlet protection can be found in the latest edition of the Ohio Department of Natural Resource’s Rainwater and Land Development Manual.

Lake County SWCD Inlet Protection Technical Bulletin #03-004

Inlet Protection Specifications

Click for larger image

Silt Fence

Silt fencing is an effective erosion and sediment control tool that can be used in various situations at a construction site.  Its basic premise is to temporarily pond up water behind it to give suspended particles such as silt, sand, and clay time to settle out in a contained area, thus preventing the sediment from leaving the site.

Lake County SWCD Silt Fence Installation Technical Bulletin #03-003

Silt Fence Specifications

Click for larger image

Stream Crossing

 Stream crossings are the most important BMPs on any given construction site.  Because they are located directly on a stream, tributary, or drainage ditch, and they almost always occur at the bottom of a slope, they have the capacity to become the principle erosion area on any given construction site. 

 Culverted stream crossings are constructed entirely of stone, rock, or recycled concrete.  No soil of any type is permitted. They are to be constructed in order to minimize disturbances to the streambed and bank.  Disturbed areas of the surrounding banks are required to be temporarily seeded and mulched.

Lake County SWCD Stream Crossing Technical Bulletin #03-005

Stream Crossing Specifications

Click for larger image

Sediment Trap

Sediment traps are very effective for sediment control and can be installed on almost any construction site.  They are generally constructed by excavating a hole or depression along a concentrated flow area in an attempt to create a pool where the velocity of flowing water can slow or even stop, thus allowing the suspended sediment to settle out.  They can also be constructed by use of an earthen embankment. They are most effective when used in combination with erosion control BMPs, but are often the only alternatives during colder times of the year when vegetation cannot be established.  Sediment traps are never permitted to be installed within the channel of a stream or ditch.

Sediment traps must be installed before earth-disturbing activity begins at the site. They should be located at or near the lowest topographic point of the site.  When possible, several sediment traps should be strategically placed across the site.  They should be sized at 67 cy/ac of total contributing drainage area.   If excavating, the slopes should not exceed 2:1 and a safety fence should be installed around the perimeter.

 Embankments for sediment traps are not to exceed 5 foot in elevation, have a top width of 4 foot and have a 2:1 slope or flatter.  A stone spillway for dewatering constructed on top of a geo-textile fabric is required for dewatering of the trap.  Sediment traps that are long and narrow are generally more effective the round or square configurations.  They should not be used for any contributing drainage area greater than 10 acres as a sediment basin should be considered for these areas.  Further information about sediment traps can be found in the latest edition of the Ohio Department of Natural Resource’s Rainwater and Land Development Manual.

Ohio DNR Sediment Trap Specifications

Click for larger image

Virginia Sediment Trap Specifications

Click for larger image

Check Dam

Check dams can be considered both and erosion and sediment control BMP.  They are typically located in low gradient flow paths such as ditches or swales and are typically small rock or stone berms placed across an area of concentrated flow.  They act as barriers to slow down the velocities of concentrated flows while helping to knock out some larger suspended sediment particles.  By slowing velocities of concentrated flows, checks dams serve as a critical BMP that protects grassed swales and ditches from down cutting and bank erosion.

Check Dam Specifications

Click for larger image

Straw Bale

Straw bales are a sediment control method that can be very effective but have limited applications. A standard bale is roughly 42”(l) x 24”(w) x 18”(h) although sizes vary depending on where they are acquired from.  They are most often used as check dams in low gradient swales to dissipate the flow of water as well as filtering out sediment that passes through them.  They can also be used to reinforce a properly installed silt fence by protecting it from heavy snow or wind.  Straw bales are no longer an acceptable practice for curb or yard drain inlet protection.

When installed, straw bales must be trenched in at least 6”.  Once trenched, they are to be staked twice per bale with 1” x 1” wood stakes that are driven in the soil to a depth of at least 10” below the bottom of the bale.  When aligning more than one bale in a row from end to end, stakes on adjacent ends of the bale should be driven in at an angle so that they cross underneath each bale for added support.  When installed as support for silt fencing, they are always to be installed on the down slope side of the silt fence.   Straw bales should not  be installed across concentrated flow areas such as in channels or streams.

Straw Bale Specifications

Click for larger image