How do you calculate the catchment area?

To calculate a catchment area, you typically start by identifying the boundaries of the area that drains into a specific point, such as a river or lake. This can be done using topographic maps, GIS tools, or hydrological models to trace the flow of water. The area can then be measured in square kilometers or acres. Additionally, factors like land use, soil type, and rainfall can be considered for more detailed hydrological assessments.