Benthic Barrier

FABRIC SPECIFICATIONS

To the best of our knowledge, the information contained herein is accurate. However, Pro Fabric Supply cannot anticipate all conditions under which the above product information and the products which we distribute or the products of other distributors or manufacturers in combination with the products which we offer, may be used. We accept no responsibility for results obtained by the application of this information or the safety or suitability of the products we distribute either alone or in combination with other products. Final determination of the suitability of any information or material for the used contemplated, or its manner of use, and whether the suggested use infringes any patents is the sole responsibility of the user. Please note: Pro Fabric Supply is a distributor of geotextile fabric, not the manufacturer. We source material from a number of different United States based geotextile manufacturers.

How To Use Benthic Barriers To Maintain Control Over Aquatic Plants

If you don't know what Benthic Barriers are, they help control invasive aquatic plants. They have weighed tarps that operate similarly to black plastic mulch. These barriers are also known as bottom barriers or bottom mats. Benthic Barriers are very effective for controlling invasive aquatic plants such as Milfoil which are found in dense, small to medium-sized patches. Very active areas of invasive plants are found in boat channels, docks, and beaches that are controlled by using Benthic Barriers.

In areas where boating is prominent, it's advised the barriers are below 5 feet in the water. Control infested areas over 500 sq ft with Benthic Barriers are not recommended because of the price tag for installation and maintenance. You might consider using small mats that are around 5 x 5 inches placed strategically to locate and kill the invasive plants while allowing native plants to continue growing.

There is one big problem with Benthic Barriers, they are not selective. They will kill or damage all plants, both invasive and native, and will have a negative impact on fish and bottom-dwelling invertebrates. In general, plants that are not targeted are minimal but not totally eliminated. Eliminating Benthic Barriers when fish are spawning and cutting back in the area chosen to treat will help.

Not more than 10% of a selective area of water or the littoral zone of the water should be covered at one time. For areas that have high infestations, only cover a specific area then move the mats to the next area and repeat this process as needed every 60 days. The materials used for the construction of these barriers include fiberglass screening, geotextile, or another heavy-duty landscape fabric, along with an absorbent pond liner, and burlap.

The weights will be lowered onto the mats in a pattern and its frequency is required to make sure the material remains flat on the bottom. If it's calculated correctly, the weights will be sufficient for holding down the mats. Another option is using rebar rods or rebars enclosed in perforated PVC pipe. The weighting devices are attached directly to the barrier material. In many cases, electronic ties are used to ensure they will stay in the right position on the mats. When using rods, some of them will be running across the width of the mat and can be attached before distribution and then rolled up in the mat to provide the required weight to get the mat to the bottom.

The rods that run along the sides of the mats will be installed later on when the mats are in place. It doesn't matter what material is being used for anchoring as the weight will vary depending on the depth of the water and other conditions including the water currents, the surface activities, the amount of plant material being covered, etc. The mats will be more stable in deeper, calmer waters. Some barrier materials are more porous allowing gases to escape under the barrier. There are other barrier materials such as geotextile and plastic tarps that are less absorbent having a habit of trapping gases. Keep in mind, the accumulation of gas can cause billowing and displacement. Before installing, you must have perforations at regular intervals beforehand. Two-inch-long slits can be created using a sharp knife or holes burned into the material using a wood-burning tool. Show caution when perforating the mats, only allow enough perforation to keep the mats from billowing without losing the mat's light-blocking integrity.

Team Members

One person will feed and guide the mats to the scuba divers who will take the mats to the lake floor. The mats are unpacked and spread out over the treatment area and then weighed down. If you have to perform manual harvesting along with barrier placement, the team might require more divers along with weed handlers, fragment spotters, etc. These barriers vary in size significantly while mats are chosen by various factors such as the size and configuration of the infested area for control. The number of people that will take on the task of installation and removal, the size of the boat to carry the mats to the assigned area, the kind of material and the amount of material, along with the required resources needed, the available storage space, etc. In general, the larger the mat, the more cumbersome it will be to move and maneuver. Most barriers are designed to be removed after the treatment period then cleaned, repaired, and stored for future use. In some circumstances, the barriers are moved from one location and sent to another location. In other cases, they are moved underwater. In some New England states, but not Maine, non-removable barriers made of non-synthetic natural fibers like burlap are installed and then left there becoming biodegradable.

Well-maintained reusable barriers can last for 10 years or longer depending on the material, how it's used, and maintenance.

Removable barriers that are installed during the growing season must be removed within 60 days of installation. The only exception to this rule are barriers that have been installed in the fall and the 60 days extends into the winter months. Mats left over the winter months must be removed at the start of the new growing season.

The cost for Benthic Barrier layering material will depend on the type, quality, and performance rating of the material. The New York State Department of Environmental Conservation estimates the added cost for installation is around $10,000 to $20,000 per acre. With the help of volunteers who are not only creative but energetic and dedicated, the lake groups in Maine are finding new creative ways to lower the cost associated with the installation of Benthic Barriers. Their impressive work is heading toward ways to have more effective methods for controlling invasive aquatic plants and without a doubt moving in the right direction toward the future.