Certified Storm Water Operator Practice Exam

What can be used to line channels when anticipated velocities are too high for grass growth?

1. Street asphalt

2. Erosion control blankets or turf reinforcement mats

3. Gravel or sand

4. Concrete or plastic liners

The correct answer is: Erosion control blankets or turf reinforcement mats

Lining channels with erosion control blankets or turf reinforcement mats is particularly effective when anticipated water velocities are too high for grass growth. These materials are designed to provide stability to the soil and prevent erosion in high-flow situations. They allow vegetation to grow and establish roots while also providing immediate protection against the forces of flowing water. The use of these mats helps facilitate the establishment of grass and other plants that can further enhance channel stability and improve water quality through filtration. In contrast, other materials such as street asphalt, concrete, and plastic liners may completely inhibit plant growth and are not conducive to natural processes that enhance water quality and habitat. While gravel or sand could be used in some cases, they may not provide the same level of erosion control or support for vegetation as erosion control blankets or turf reinforcement mats. The correct choice thus highlights the importance of promoting vegetation while also managing the potential for erosion in channels with high water velocities.