Several types of erosion control blankets are in the process of being installed on a slope to evaluate their effectiveness.

Soil Stabilization using Erosion Control Blankets

By Mel Mathews, CPESC

Erosion Control Professionals are often faced with the challenge of stabilizing that stubborn slope. A possible solution might include the use of Erosion Control Blankets. Erosion Control Blankets can be effective in minimizing the erosive effect of rainfall when used to cover bare or newly planted soil. Their use stabilizes the soil to protect new plantings and reduces the potential for introducing sediment into storm water run-off, a win-win situation! Erosion Control Blankets can be specified by designers for protection of newly graded slopes, open areas, or drainage swales to allow germination of seed mixes and plantings. Contractors may also choose to use Erosion Control Blankets for temporary erosion control on highly erodible areas.

What are Erosion Control Blankets?
Erosion Control Blankets are biodegradable materials that can be used to protect disturbed slope and channel areas from wind and water erosion. The blanket materials are natural materials such as straw, wood excelsior, coconut, or are geotextile synthetic woven materials such as polypropylene.

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Erosion Control Blankets are effective for soil stabilization on steep to moderate slopes, new landscaped areas, and drainage swales and ditches that are to be planted or seeded. Additional desirable attributes include:

• They increase water infiltration into the soil.
• When used with a seed mix, they protect the mix from being eroded during heavy rainfall or wind.
• They increase the retention of soil moisture to promote seed germination.
• Most importantly, they reduce soil erosion.

There are many types of products available for erosion control. Product selection is based on many factors, such as:

• Duration required (short or long term temporary usage).
• Effectiveness compared to other soil stabilizers.
• Relative cost of purchase, installation and maintenance.
• Visual impact to the public.
• Environmental acceptability. Synthetics may biodegrade more slowly than natural materials.

Getting the Most from Erosion Control Blankets
Erosion Control Blankets provide excellent short and long term temporary erosion control - when properly installed and maintained. Proper soil surface preparation is critical to the effectiveness of the installation:

• All rocks, clods, debris, and vegetation should be removed to ensure full contact between the blanket and the soil surface.
• Follow the manufacturer's recommendations for seed application requirements when used with blanket installation.
• The blanket should be anchored to the soil using metal wire staples as recommended by the manufacturer.
• The staples should be driven through the blanket and into the soil, flush with the soil surface.
• Erosion Control Blankets should not be used where final vegetation will be mowed, because material and staples may be caught in the mowers.

Inspections and Maintenance
As with any erosion control method, the result depends on the product selected, the installation quality, and the commitment to maintenance. The inspection and maintenance of Erosion Control Blankets should be conducted as follows:

• Inspect the site during installation.
• Inspect the installation before, during and after significant rain events.
• Repair or replace all damaged materials.
• Recompact all soil washout areas.

STANDARD TERMINOLOGY FOR ROLLED EROSION CONTROL PRODUCTS

Rolled erosion control product (RECP), A temporary degradable or long-term non-degradable material manufactured or fabricated into rolls designed to reduce soil erosion and assist in the growth, establishment and protection of vegetation.

Temporary degradable, An RECP composed of biologically, photochemically or otherwise degradable materials that temporarily reduces soil erosion and enhances the establishment of vegetation.

Long term non-degradable, An RECP composed of non-degradable materials that furnishes erosion protection and extends the erosion control limits of vegetation for the design life of a project.

Erosion control net (ECN), A planar woven natural fiber or extruded geosynthetic mesh used as a component in the manufacture of RECPs, or separately as a temporary degradable RECP to anchor loose fiber mulches.

Open weave textile (OWT), A temporary degradable RECP composed of processed natural or polymer yarns woven into a matrix, used to provide erosion control and facilitate vegetation establishment.

Erosion control blanket (ECB), A temporary degradable RECP composed of processed natural or polymer fibers mechanically, structurally or chemically bound together to form a continuous matrix.

Turf reinforcement mat (TRM), A long term non-degradable RECP composed of UV stabilized, non-degradable, synthetic fibers, nettings and/or filaments processed into three dimensional reinforcement matrices designed for permanent and critical hydraulic applications where design discharges exert velocities and shear stresses that exceed the limits of mature, natural vegetation. TRMs provide sufficient thickness, strength and void space to permit soil filling and/or retention and the development of vegetation within the matrix.