Benthic Barrier

Nuisance vegetation around water use areas such as docks and swimming beaches can put a crimp on enjoying a waterway. Invasive species such as hydrilla can choke an area and make it nearly unusable. One solution is a geotextile benthic barrier.

A benthic barrier is basically a blanket attached to a frame that covers the bottom of a lake. It functions to block sunlight and cover over existing vegetation. Use of a geotextile blanket attached to a wooden frame is an effective method for building a benthic barrier. These barriers will effectively control most aquatic plants that are not free floating. Barriers no larger than 12’ x 12’ are the most effective.

Rotting vegetation under the barrier will create gas bubbles and cause it to billow up a little. This is a problem for even very porous materials like window screen. Therefore, it is very important to securely anchor the barrier to the lake bottom with native cobbles or sandbags. Also, rebar ballast will need to be attached to the geotextile since it will float. Securing the barrier is very important to avoid navigation and swimming hazards.

• Geotextile Benthic Barrier
• Greatly Reduce Nuisance Vegetation
• Kill Off Invasive Species
• Can Be Installed By Homeowner

Once installed, monitor the frame to make sure it is staying in place and excessive air bubbles are not forming. This probably needs to be performed 1 to 2 times per month. If air bubbles are an issue, the frame will need to be partially lifted to “burp” it or you will need to cut additional slits in the fabric to release the bubbles.

Benthic barriers can be built and installed by a home owner. It is strongly suggested to install in winter or early spring when plants have died back. If installation must take place in the summer, cut or pull the existing vegetation to reduce the amount of gas produced by the rotting vegetation.

Both woven and nonwoven geotextiles have been used effectively for the blanket of a benthic barrier. US Fabrics suggests US 160NW nonwoven geotextile. Visit the US 160NW product page to download an installation guideline.