Fiber Rolls (e.g., Wattles)

What – Fiber rolls, commonly called wattles, are prefabricated rolls manufactured from rice straw and wrapped in degradable netting.  In some cases, on-site woody debris can be rolled in netting to reduce costs.  Rolls are ~ 9 inches in diameter and up to 25 feet long. 

Purpose – Intended for low-surface flows not to exceed 1 cubic foot per second. They are not for stream channels or gullies.  They are intended to reduce erosion by shortening the slope length to slow overland flow velocity as well as trap sediment and provide a seedbed for vegetative recovery.

Effectiveness – Studies indicated that erosion barriers may reduce runoff and sediment yields for low intensity rain events (< 1.8” per hour), but are unlikely to have a significant effect for high intensity rain events.  Wattles reduced total runoff and peak flow rates (Robichaud et al. 2008 and 2010).

Where

• Areas of high- and moderate-burn severity.
• Slopes with < 40% ground cover.

Cost – $1100–4000 per acre.  Additional factors include:

• Location and terrain
• Access
• Experience of crews

How to Links – See USDA BAER Catalog page 51 (PDF page 59); and NRCS Contour Wattles Fact Sheet.