What is the maximum total contributing drainage area to any individual grass channel?

The maximum total contributing drainage area to any individual grass channel is set at 5 acres because grass channels are designed to manage and treat stormwater runoff effectively while also maintaining the integrity of the channel itself and the surrounding environment.

Grass channels are intended to slow down runoff, allowing for sedimentation and infiltration, which helps filter out pollutants. If the drainage area is too large, it can lead to excessive flow velocities and increased erosion, undermining the channel's effectiveness in managing stormwater. A 5-acre limit allows for optimal performance of the grass channel while ensuring that the flow can be adequately handled without causing damage to the vegetation or leading to sediment loss or overtopping.

This maximum is established based on research and guidelines that balance the channel’s design with practical land-use considerations, i.e., not overwhelming the channel with too much water, which can occur if the drainage area exceeds this threshold. This ensures that the intended functions of the grass channel—such as sediment removal and pollutant filtration—can still be achieved within a manageable size.