What are long cylinders filled with natural materials used to control erosion and sediment called?

The correct answer is that long cylinders filled with natural materials used to control erosion and sediment are called wattles. Wattles are typically made from natural fibers, such as straw or coconut coir, and are used as an erosion control measure in landscaping and construction sites. Their cylindrical shape allows them to be placed in rows to create barriers that slow down water flow, helping to capture sediment and reduce erosion as well as improve water quality.

Wattles function effectively by dissipating energy from flowing water and providing a physical barrier that allows sediments to settle out. They are an environmentally friendly option as they often decompose over time, contributing nutrients back to the soil. This aligns with sustainable practices in erosion control.

Other options listed, like biofilters, silt socks, and fiber rolls, serve related purposes in erosion control and sediment management but are structured or formulated differently. For example, biofilters are typically designed for filtering water rather than specifically controlling erosion, silt socks are tubular containers filled with a filter material used for sediment control but are not as versatile as wattles in some applications, and fiber rolls are similar but often larger and used for different specific applications in managing runoff and erosion.