Straw wattles, also called fiber rolls or sediment logs, are tubes of straw, coconut fiber, wood excelsior or compost wrapped in netting. Placed along the contour, they slow sheet flow, trap sediment, and break up long slopes so water can't build speed.
Where wattles work
- Slopes: rows across the slope act as slope breaks and short-term sediment barriers.
- Perimeter control: along the downslope edge of small disturbed areas, a common alternative to silt fence. The EPA CGP's perimeter control examples include similar devices such as compost filter socks and filter berms.
- Stockpiles: around the downgradient sides of soil piles.
- Around inlets and on pavement: weighted rolls or compost socks where you can't trench or stake.
- Ditch check dams: in small swales, with care, though rock or manufactured checks are often better for flow.
Not for: large drainage areas, concentrated flow they can't handle, or live streams.
Typical installation
State BMP manuals set exact specs; typical practice:
- Lay out rows on the contour, perpendicular to the flow path.
- Dig a shallow trench, commonly a few inches deep (often 2 to 4 inches), so the roll sits in the soil and water can't flow underneath.
- Place the wattle in the trench and backfill and compact soil against the upslope side.
- Stake through the roll with wooden stakes, commonly every few feet (often 3 to 4 feet) and within a foot of each end, driven firmly so they hold.
- Abut ends tightly or overlap them so there are no gaps, and turn the ends up slope so water can't run around.
Closer row spacing is used on steeper slopes; your BMP manual will list spacing by slope gradient.
On pavement
Where trenching isn't possible, use weighted fiber rolls or compost filter socks designed for pavement, butted tightly with no gaps, and check them after every storm.
Inspection and maintenance
- Remove sediment before it builds up too high. The EPA CGP requires removal from perimeter controls before sediment reaches one-half of the above-ground height.
- Repair undercutting, washouts and gaps between rolls.
- Replace rolls that are crushed, split or degraded.
- Biodegradable rolls can be left in place at final stabilization if your permit and plan allow.
Sources and official references
Last reviewed: October 25, 2026 · Free general education based on the Clean Water Act, EPA NPDES rules and the EPA Construction General Permit. Your governing permit (EPA, state, tribal or local) controls. This is not legal advice, not EPA-approved, and not a California QSP/QSD or other state credential, and it does not issue a certificate. Nothing you enter on this page is saved or sent.