Material and system for minimizing erosion

Claim 1

A material for use as a silt fence, one marginal edge of which is adapted to be buried into the ground and the other marginal on which is adapted to be supported by uprights or the like, above the ground comprising an elongated first strip of material having a relatively uniform porosity which strip of material is fabricated from filaments of less than about 5 denier, an elongated second strip of material fabricated from yarns in a grid pattern, such yarns being in the aggregate of about 3,000 to 7,000 denier per linear inch in each direction and having from 2 to about 8 yarns per inch in each direction, said first and second strips being fabricated from material which does not readily deteriorate, and said first and second strips being attached together to provide a composite strip, the composite strip having a Frazier air permeability of 100 to 1,000 cubic feet per square foot at a pressure of 1/2 inch or water.

Claim 8

A system for retarding the flow of silt and the like along the ground in ground water comprising trench generally transverse to the anticipated line of ground water flow, providing supporting posts in the ground at spaced intervals on the downstream side of said trench, a composite strip of material disposed along said line of posts, said material comprising an elongated first strip of material having a relatively uniform porosity which strip of material is fabricated from filaments of relatively small diameter, an elongated second strip of material fabricated from filaments in a grid pattern, such filaments being of relatively large diameter relative to the filaments into said first strip of material and having from two to about eight filaments per inch in each direction, said first and second strips being fabricated from material which does not readily deteriorate, and said first and second strips being attached together to provide said composite strip, said composite strip having a Frazier air permeability of 100 to 1000 cubic feet per square foot at a pressure of 1/2 inch of water, one marginal edge of said material being folded over to provide a hem, the edge being attached to the body of the sheet to provide an elongated pocket running along that edge of the sheet and an elongated flexible tensioning member disposed in said pocket, means attaching the longitudinal tensioning member to said ports above the ground level, the other marginal edge of said material being disposed in said trench, said trench backfilled on top of said last mentioned marginal edge to anchor that edge in the ground, and the first strip of material being disposed on the upstream side of said composite strip of material.

Claim 9

A system for retarding the flow of silt and the like along the ground in ground water comprising trench generally transverse to the anticipated line of ground water flow, providing supporting posts in the ground at spaced intervals on the downstream side of said trench, a composite strip of material disposed along said line of posts, said material comprising an elongated first strip of material having a relatively uniform porosity which strip of material is fabricated from filaments of relatively small diameter, an elongated second strip of material fabricated from filaments in a grid pattern, such filaments being of relatively large diameter relative to the filaments into said first strip of material and having from two to about eight filaments per inch in each direction, said first and second strips being fabricated from material which does not readily deteriorate, and said first and second strips being attached together to provide said composite strip, said composite strip having a Frazier air permeability of 100 to 1000 cubic feet per square foot at a pressure of 1/2 inch of water, one marginal edge of said material being folded over to provide a hem, the edge being attached to the body of the sheet to provide an elongated pocket running along that edge of the sheet and an elongated flexible tensioning member disposed in said pocket, means attaching the longitudinal tensioning member to said ports above the ground level, the other marginal edge of said material being disposed in said trench, said trench backfilled on top of said last mentioned marginal edge to anchor that edge in the ground, and the first strip of material being disposed on the upstream side of said composite strip of material.