Sizing of a sediment trap or basin is based on which area?

The sizing of a sediment trap or basin is based on the total contributory drainage area because this measurement directly influences the amount of water and sediment that will flow into the trap or basin during a rain event. The contributory drainage area represents all the land that drains towards the trap or basin, including impervious and pervious surfaces. This information is crucial for designing a system that can adequately handle the expected runoff and sediment load. Ensuring that the trap or basin is appropriately sized to the total contributory drainage area helps in effectively managing sediment control and preventing erosion, while also promoting the sustainable management of water resources. Thus, the focus on this specific area ensures that the design can accommodate peak flows and mitigate sediment transport efficiently.