To Pool or Not to Pool - Sediment Control Techniques

Sediment control solutions in the best management practice (BMP) toolbox are plentiful today. Both natural and manufactured options exist. Selecting the proper solution for a project can be challenging at times because there are so many choices. In addition, two sediment control techniques are commonly used interchangeable, but they are far from being the same. Some methods are designed to pool water and use gravity as the main force to encourage sedimentation. Others are designed to allow flow through the structure or device to encourage filtration of contaminated runoff. Velocity dissipation is provided by both techniques at various levels.
One key factor of sediment control products is whether or not they allow stormwater through them. Sediment control products can be separated as damming, or those that are intended to pool runoff, and filtering products, or those that are designed to allow flow through them. Filtering products are defined as those with a flow rate of ≥35 GPM/ft2 according to ASTM D5141. Damming products are designed with a flow rate of <35 GPM/ft2. Matrix density is also an important factor to consider that is related to the flow rate of the sediment control solutions.
Damming and filtering products react and perform differently during hydraulic events. Hydraulic forces are affected accordingly depending on the sediment control technique targeted. As a result, the products and techniques have their limitations and are not interchangeable. Benefits of each type of sediment control products and techniques will be discussed along with performance differences in various applications.