The standard Lake Bottom Blanket comes to you un-weighted. We recommend that you purchase locally 3/8″ rebar and install it into the blanket. For most applications, this is enough weight ( approx. 40 lbs. ) to hold the blanket in place. Now if you have motorboat traffic in the area and its less then 5 feet deep you may want to use 1/2″ rebar (which doubles the weight). Also, each section of the Lake Bottom Blanket has small vents to allow decomposition gases to escape. This system also comes with a caution buoy to help identify that there are weed control blankets in the water. But, if big boats are still plowing thru the area you’re covering then this is not the product for you, and actually, there are no benthic mats available that are able to handle high boat traffic of this nature.