Monofilament filter fabric placed on a shoreline

The combination of high strength and excellent hydraulic characteristics make monofilaments the filter fabric of choice for bulkhead and erosion control. Monofilament filter fabrics have a high percent open area (POA). Percent open area is the area of distinct, uniform and measurable openings in a filter fabric. A high POA assures that both water and soil particles have direct paths through the fabric. Nonwoven, woven slit film and combination fabrics have little or no percent open area and often trap soil particles, clogging the geotextile.

To determine when a fabric becomes clogged, a gradient ratio test is performed. Gradient ratio is defined as the ratio of the average hydraulic gradient across the fabric and the 1" of soil immediately next to the fabric, to the average hydraulic gradient across the 2" of soil between 1" and 3" above the fabric.

The US Army Corp of Engineers determined that if a gradient value exceeded 3, the fabric is considered clogged. Tests were conducted to determine what geotextiles resisted clogging, based on the gradient ratio of the geotextiles. The results of 6 types of geotextiles are presented in the graph below:

Manufactured in 6' and 12' widths. US Fabrics also provides custom widths and lengths, eliminating waste and reducing expensive overlaps. By using an over edge J Seam with a 401 lock stitch, seam strength approaches 90% of the geotextile strength.

• Bulkhead, seawall and shoreline erosion control