Certified Storm Water Operator Practice Exam

How much lower should the center of a check dam be compared to the outside edges?

1. 5 inches

2. 9 inches

3. 12 inches

4. 15 inches

The correct answer is: 9 inches

The recommended depth difference between the center of a check dam and the outside edges is significant for ensuring the structural integrity and functionality of the dam. A drop of 9 inches allows for effective water pooling, which helps to reduce erosion and sediment transport by slowing down the flow of water. When water flows over or through a check dam, the design must accommodate a certain volume of water without undermining the dam structure itself. This difference helps to create a natural barrier that allows sediments to settle behind it, which is crucial in maintaining water quality and controlling stormwater runoff. When the center of the check dam is properly lowered, it enables better water management by creating a pool that can absorb sudden rainfall and reduce the likelihood of downstream flooding. Maintaining this specific height difference ensures that the check dam performs its intended function effectively. In contrast, a different height difference might either lead to insufficient performance, where the water does not pool properly, or could pose a risk of overtopping, ultimately leading to potential failure of the dam. Thus, a 9-inch drop is the optimum choice for effective stormwater management.