Straw wattles, also commonly known as contour straw wattles, straw tubes and straw worms, are used near construction projects, in ditches and in other areas with a significant slope and inadequate vegetation. They reduce erosion, increase filtration and retain soil for one to two years, making them ideal for temporary protection while permanent vegetation becomes established. Proper installation of straw wattle helps to ensure it remains stable and is able to control erosion at its site for an acceptable length of time.
Mark locations to place straw wattle, using wire flags, small stakes or sticks, while locating and following an imaginary line that remains at the same elevation. Use a hand level to ensure you remain on level ground. The straw wattle should be perpendicular to the slope. Plan for a slight downward angle at the end of each row of wattling to stop water from pooling in the middle of the row. In a sloped area large enough to require multiple lines of straw wattle, spacing depends primarily on the slope's steepness. In an area with a 1-to-1 slope gradient, or a 1-foot vertical change per 1 foot of horizontal distance, for example, plan to space wattle rows no more than 10 feet apart. If an area has a 4-to-1 slope gradient, or 1-foot vertical change per 4 feet of horizontal distance, plan to space rows of wattle about 40 feet apart. Where soil is soft and loamy, plan to space the wattle rows slightly closer together. You can leave more space between wattle rows if the soil is hard and rocky.
Dig a shallow trench along each location you marked. If the soil is hard and rocky, make the trench 2 to 3 inches deep. If the soil is soft and loamy, dig a trench 3 to 5 inches deep.
Lay straw wattle in each prepared trench so that it is solidly in contact with the soil on the trench's bottom. Where more than one wattle is needed to complete a line, ensure that the ends of the two sections of wattle touch each other tightly.
Pound a wooden stake into each end of each wattle and every 4 feet in the middle of each wattle. Each wooden stake should be 18 to 24 inches long and either 2 by 2 inches or 1 by 2 inches wide. Angle the stakes so they are perpendicular to the soil surface, and drive the stakes at least 6 inches into the ground, leaving 2 or 3 inches of each stake visible above the top of straw wattle.
Pack the soil you removed to dig the trenches along the uphill side of straw wattle, tamping it with your foot. The packed soil keeps water from flowing under the straw wattle.
Things You Will Need
- Wire flags, small stakes or sticks
- Hand level
- Measuring tape
- Mattocks, shovel or other trench-digging tool
- Wooden stakes, each 18 to 24 inches long and 2 by 2 inches or 1 by 2 inches wide
- Mallet or hammer
- If you want to install straw wattle next to a sidewalk or behind a curb, dig a trench next to the structure and place the wattle in the trench, or lay it prior to adding topsoil and sodding, seeding or otherwise finishing landscaping at the site. Keep the wattle 1 foot from an inlet and storm drain, and angle the wattle so it directs flowing water toward the drainage structure.
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