BMP Supplies Type 1 DOT Turbidity Curtains are manufactured to meet DOT approvals for curtains to be deployed in water with little to no flow rates. Made from 18oz PVC Coated material, BMP Supplies Type 1 DOT Turbidity Curtains are durable and economic option for your project. The Type 1 curtain is recommended for construction sites located in protected areas that are exposed only to light winds and to current velocities of less than one foot per second. This type of site may include ponds, shallow lakes, small streams and marshes. Standard stocking size is 5′ depth, however custom sizes are available