Which of the following is a reason for having a rooftop disconnection to an alternative practice?

Rooftop disconnection is a stormwater management practice where runoff from rooftops is diverted to an alternative treatment practice, rather than being directed to the conventional storm drain system. This approach aims to enhance the quality of stormwater by allowing for better infiltration and treatment before the water reaches receiving waters.

The rationale behind the need for a rooftop disconnection specifically relates to the narrow filter width. When green infrastructure practices, such as bioretention areas or infiltration trenches, are designed, they often have specific physical dimensions that must be adhered to in order to ensure adequate performance. A narrow filter width can lead to limitations in the treatment process, as it may not provide sufficient space for effective filtering and infiltration of pollutants before the runoff is released into the environment. By disconnecting rooftops and directing runoff to an alternative practice with an appropriate width, the stormwater management system can achieve its intended purification goals more effectively.

Other factors like excessive lot size, high water quality credit requirements, and increased sediment discharge could influence stormwater practices but do not directly reason for implementing a rooftop disconnection in the context of filter width limitations. Thus, focusing on the dimensions and design specifications in terms of managing runoff effectively highlights why a narrow filter width solidifies the need for this strategy.