In stormwater systems, what is the intended outcome of lengthening the flow path of stormwater?

Lengthening the flow path of stormwater is primarily intended to limit erosion and promote filtration. When stormwater takes a longer route, it allows for more opportunities for infiltration into the soil, which can filter pollutants and reduce the velocity of the flowing water. This process helps to stabilize the soil, thereby minimizing erosion due to the reduction of concentrated flow, and promotes the natural cleansing of water as it interacts with various substrates.

As stormwater flows over longer distances, it encounters vegetation, soil, and other natural features that enhance filtration and absorption, effectively reducing the amount of sediment and pollutants that can enter water bodies. This practice is a key principle in sustainable stormwater management, as it aligns with the goals of maintaining water quality and ecosystem health.

In contrast, other choices such as increasing runoff velocity, creating more impervious surfaces, or minimizing treatment effectiveness do not support the goal of sustainable stormwater management and would likely lead to poorer water quality and increased environmental degradation.