What must be demonstrated for proposed developments to prevent increasing peak runoff rates into existing channels?

For proposed developments to prevent increasing peak runoff rates into existing channels, demonstrating site design that reduces the overall runoff is essential. This approach involves incorporating strategies that effectively manage stormwater through design elements such as permeable surfaces, green roofs, rain gardens, and retention basins. By strategically planning and designing the site, developers can reduce the volume and speed of runoff that enters existing channels, which is crucial for maintaining the integrity of those channels and preventing erosion or flooding.

Simply conducting a visual inspection does not provide the detailed analysis needed to ensure that peak runoff rates will not increase. Engineering calculations are important to quantify runoff and assess impacts, but they are part of the broader design considerations. While minimizing construction activities can contribute to managing runoff, it does not directly address the need for a proactive design to manage stormwater effectively. Therefore, focusing on a comprehensive site design is the most effective method to achieve the goal of preventing increases in peak runoff rates into existing channels.