Erosion control matting or blanket is a type of protective blanket made from straw, fibers, plant residue, or plastic. The blanket is preformed and used for protecting soil from overland flow and impact of precipitation in any form. It also helps in retaining moisture and facilitating an even establishment of vegetation. Erosion control blanket is also known as Rolled Erosion Control Product (RECPs).
This guide will explain the various methods of installing erosion control blankets and maintaining them.
Factors to Consider Before Installing Erosion Control Matting
Erosion control blankets can be in the form of temporary and permanent preformed matting. Temporary matting is generally installed on seeded areas whereas permanent blankets are used for landscaped areas. Several factors are taken into consideration while choosing an erosion control blanket. These are:
Steepness of slope
Length of slope
Soil conditions
Runoff velocities
Depth of flow
Time to establish vegetation
Good to Know Information before Installation
Erosion blankets work best with vegetation.
Groundcover plants have several natural erosion check benefits, including protecting against strong winds, structuring unstable soil, and soaking up runoffs after rain.
Small Site Installation
What will you need?
Erosion control matting
Pins or staples
Shovel
Tiller or aerator
Installation Method
1. Clear installation site
Inspect the site closely by making a circuit of the site. Look for things like branches, rocks, dirt clods, roots or unwanted vegetation. Use a shovel, tiller, aerator, or pitchfork to break compacted soil once you have cleared the site (if necessary). It is important for the erosion control blanket to lie directly on the topsoil without any obstructions.
2. Dig a trench if installing on a slope
You will need to dig a shallow trench at the top if installing on a slope or a hill. Remove 1/2 ft. (0.15 m) of soil using a shovel or space in a straight line. This slight depression is necessary to anchor your erosion control blanket and prevent it from being dragged downwards by gravity. You can skip this step if installing the erosion control matting on a flat surface.
3. Line the shallow trench
Free 3 feet of the material from its roll and line it over the depression. Smooth it using your hands, ensuring at least 6 inches of material is resting on top of the trench. This step is important to settle the blanket’s hold. Do not unroll the remaining part before securing the loose end properly.
4. Use fasteners to tack the blanket
Your erosion control matting would come with its own specially designed staples or pins for easy installation. Read manufacturer directions and space the fasteners as directed. Sink them deep at the center of the shallow trench using a rubber mallet or a hammer. Generally, fasteners should be placed 6 – 8 inches from the loose edge on each side and the third into the center point.
5. Overlap additional blanket edges
You need to lay additional blanket edges under the vertical edges of the matting beside it. This will help in creating an overlap which will prevent any soil from being left exposed. An average overlap of 4 inches is recommended by most manufacturers. However, you should use your judgment and take a call depending on the unique dimensions of the erosion control blankets you are working with.
6. Refill the trench
Use your spade or shovel to reline the trench with the soil you removed earlier. Make sure the erosion control blankets are firmly staked. Smooth the soil afterwards by patting the surface lightly and tamping it down. The upper end of your blanket should stay secured with the fasteners and compact soil.
You should inspect the anchor trench every week to recompact or replenish the soil if required. This is necessary after rainfall as well.
7. Unroll and fasten remaining blanket
You should wait to unroll the blanket until you have properly secured the loose side by staking it inside the trench. Fasten the remaining erosion control blanket every 2 – 3 feet. Drive a staple into overlapping vertical edges at regular intervals. Make sure you line the fasteners symmetrically and sink them completely in the soil. Improperly spaced fasteners can cause the blanket to pull, twist or bunch which will render it ineffective.
Large Site Installation
What will you need?
Erosion control matting
Compact all-terrain vehicle
Unrollers and clip-on tow lines
Pins or staples (included)
Utility knife
Tiller or aerator
1. Prepare the site
You need to take appropriate measures to prepare the site for erosion control matting installation. This is especially important for large sites because it can get difficult to fix problems later. You may need to aerate and fertilize the soil if you want to speed up vegetation.
Make sure you install the erosion control blankets within 24 – 48 hours of seeding to promote healthy germination. The matting contains loosely woven mesh that allows plants to grow easily.
2. Use twin unroller units to attach the roll
You will need an all-terrain utility vehicle, such as Gator or a four-wheeler to make the installation easy. Use a twin unroller unit to attach the rolled erosion control blanket to the ATV. Slide the long arms into each open cavity on both sides and connect using built-in clips.
Make sure you arrange each roll so that the indicators on the outer packaging are in the direction you will be unrolling. Tractors can also be used to tow and unroll erosion control blankets. However, make sure the vehicle is not heavy enough to result in soil compaction.
3. Get into position at any corner of the installation site
You need to move the rolled blanket to the outer perimeter of the installation site. Cut away the bands or plastic wrap holding the roll and pull a little bit of the free end loose. Lay it down flat on the ground to begin unrolling.
If laying multiple erosion control blankets in the same area set them all neatly besides one another at the starting point. This will prevent you from having to move back and forth between installations.
4. Start unrolling
Start driving slowly to unroll the erosion control matting. Make sure you cruise at a slow, deliberate speed. The wheels on the twin unroller unit move at the same speed as the vehicle. You will also need to take care to move in a straight line to ensure the unrolling happens smoothly. The blanket should lay flat on the surface without tears or drags.
You can use another person to hold the blanket in place using landscape staples or large rocks as anchors. This will ensure the unrolling is done in a smooth and quick fashion. It may not be possible to get the erosion control blankets lined straight at first. You will need to adjust them manually once all blankets are unrolled.
5. Overlap edges of all additional blankets
Make sure you overlap the edges of erosion control blankets while unrolling them. The vertical edge should be a minimum of 2 inches under the first roll’s edge. This helps in providing optimal soil coverage. Make sure you limit the overlapping to 6 inches. Anything further will only result in material wastage.
6. Fasten the soil erosion blankets
You will need to walk the length of the blanket and fasten the edges every 3 – 5 feet. Use the staples and pins provided with the erosion control matting rolls. For erosion control blankets that are laid side by side, you should take care to stake the fasteners on the overlapping edges.
This should make your erosion control blankets secure enough to withstand precipitation, wind and animal activity. You can use a special applicator device that makes the process of sinking fasteners into the soil quick. Make sure you use fasteners as directed or it may result in complications later.
Inspect Erosion Control Blankets Regularly
You should make it a point to inspect the erosion control blankets at least once every seven days or as is reasonable to you. You should immediately inspect the site after a rainfall event (or at least within 48 hours) if adequate vegetation is yet to be established. This will give you a clear picture about storm-water runoff. Precipitation above ½ inch usually warrants a quick inspection within 24 hours.
While inspecting the erosion control blanket installation site after seeding, you should verify the top soil is free of rocks and relatively smooth. It is alright for rocks smaller than 2 inches to be left alone. However, the site should be free of vegetation clumps, protruding roots, sticks, debris, and trash. Check the staking pattern after installation to see if everything is done right and fitted properly.
Look at soil contact, anchor slot backfill, overlaps and shingling as well. Upslope erosion control blankets should be overlapping the downslope blankets. You need to pay particular attention when installing erosion control matting on long steep slopes, especially if they are below waterline in channels and ditches.
Make sure you cordon off the area after installing the blankets to keep vehicles, equipment, and foot traffic away. When installing after a rainfall event you should look for sags or “pulls” on steep slopes. This is where the runoff or weight of precipitation clings to the erosion control blanket to pull it away downhill.
It is possible for firmly anchored staples and slots to give way under heavy deluge. You can do proper damage control after identifying the problem area and fixing it without delay. Look for areas where any overlap may have been flipped up by animals or runoff, or pulled apart.
If you find any signs of protected animal species around, you should look for crawling animals that may be trapped under the blanket.
Maintaining Erosion Control Matting
It is vital for erosion control blankets to be inspected and maintained properly until natural vegetation is established. You may need to irrigate blankets to germinate seedlings quickly or as a helping hand during long dry spells. It is recommended that you irrigate the area in the evening or when it is cloudy to minimize evaporation.
Bulging may appear because of emerging seedlings that push the blanket off the ground. This problem occurs when stapling or staking is done improperly. You should install stakes at least 1.5 feet apart, especially in the bulging areas, as soon as possible. This is to make sure that grass or groundcover plants find their way through the matting.
In the event of sagging, you should consider installing longer anchors in a close matrix pattern. You can use shears or scissors to cut large sags or bulges and stake the area as properly as possible. You may also consider using mulch control netting and hand scattered straw for spot repairs.
Higher longevity blankets are known to trap or hinder animal species. You may consider using short-term blankets in such a situation and replace them every few months. Otherwise, you can spot repair problem areas within the erosion control blanket using straw, sod, or hydromulch.