COMPONENTS FOR SILT FENCES

meters feet apart] [as shown on the drawings].

e. Perpendicular to the flow in the bottom of new drainage ditches,

channels, and swales. Rows shall be spaced [a maximum of [_____] m feet

apart] [as shown on the drawings].

f. At the entrance to culverts that receive runoff from disturbed

areas.

g.

[_____].]

1.4.2.3

[Diversion Dikes

Diversion dikes shall have a maximum channel slope of 2 percent and shall

be adequately compacted to prevent failure. The minimum height measured

from the top of the dike to the bottom of the channel shall be 0.5 m 18

inches. The minimum base width shall be 1.8 m 6 feet and the minimum top

width shall be 0.6 m 2 feet. The Contractor shall ensure that the

diversion dikes are not damaged by construction operations or traffic.

Diversion dikes shall be located as shown on the drawings.]

PART 2

PRODUCTS

2.1

COMPONENTS FOR SILT FENCES

2.1.1

Filter Fabric

The geotextile shall comply with the requirements of ASTM D 4439, and

shall consist of polymeric filaments which are formed into a stable network

such that filaments retain their relative positions. The filament shall

consist of a long-chain synthetic polymer composed of at least 85 percent

by weight of ester, propylene, or amide, and shall contain stabilizers

and/or inhibitors added to the base plastic to make the filaments

resistance to deterioration due to ultraviolet and heat exposure.

Synthetic filter fabric shall contain ultraviolet ray inhibitors and

stabilizers to provide a minimum of six months of expected usable

construction life at a temperature range of -18 to 49 degrees C 0 to 120

degrees F. The filter fabric shall meet the following requirements:

FILTER FABRIC FOR SILT SCREEN FENCE

PHYSICAL PROPERTY

TEST PROCEDURE

STRENGTH REQUIREMENT

Grab Tensile

ASTM D 4632

445 N min.

Elongation (%)

30 % max.

Trapezoid Tear

ASTM D 4533

245 N min.

Permittivity

ASTM D 4491

0.2 sec-1

AOS (U.S. Std Sieve)

ASTM D 4751

20-100