For accurate irrigation evaluation using catchments all catchments need to the same size and the area of the opening needs to accurately calculated. This tool will compute the area for round or square catchments. If using square catchments with rounded corners (ex. freezer containers) then choose this option and 5% will be deducted from the area. If the edge of the catchment is not sharp then measure to the middle of the edge.
Tools on this site are intended for education purposes only and are not intended for commercial use. For more information contact Michael Spiess at California State University, Chico.