Biofilter bags for erosion control

A water permeable erosion control bag, comprising:

• a flexible plastic tubular container having mesh walls through which water can flow;
• and
• discrete wood fragments within the container that do not have smooth surfaces that tend to stick together when wet, such that the wood fragments resist adherence to other wood fragments within the container and are of a sufficient size to be retained within the container without becoming clogged with sediment that may be carried by the water, wherein the wood fragments are large enough to be retained by a 3/8 inch separator screen, and yet sufficiently small to pass through a 11/2 inch separation screen, so that the wood fragments are larger than 3/8 inch but smaller than 11/2 inch.

A method of controlling erosion in a region of run-off, comprising the steps of:

• providing a flexible container having mesh walls through which water can flow, and discrete wood fragments loose within the container, wherein the wood fragments do not have smooth surfaces that tend to stick together when wet, and the wood fragments resist adherence to other wood fragments within the container, and the wood fragments are sufficiently large to be retained within the container and slow the flow of water through the container to allow silt carried by the water to be trapped by the container, and the container walls are sufficiently flexible to allow the wood fragments to conform to a surface on which the container sits;
• and
• placing the container on a surface in the region of run-off to slow the flow of water and allow the silt carried by the run-off to be retained by the wood fragments as water flows through the container, wherein the step of providing wood fragments within the container further comprises providing hammer milled wood fragments that do not pass through a separation screen that retains fragments having a dimension larger than 3/8 inch, so that the fragments within the container are larger than 3/8 inch.

A water permeable erosion control bag comprising:

• a polyethylene mesh having mesh openings of about 1/2 inch, wherein the mesh is filled with wood fragments to form an elongated tube approximately 12 inches in diameter and at least 30 inches long;
• and
• wherein the wood fragments consist essentially of hammer milled wood fragments that pass through a 11/2 inch separation screen but not through a 3/8 inch separation screen, and the wood fragments do not have smooth surfaces that tend to stick together when wet and form a mass of fragments that prevents flow of water through the bag, and the wood fragments when wet resist adherence to other wood fragments within the container without becoming clogged with sediment carried by the water.