Visually, the pink box is the basin, the light pink polygon is the pond, and the green is the flooding area. What I am trying to calculate is the area of green that is on the white background over the total area of white.
Using the toolbox I currently have
"Intersect" (to cut the flooding polygons within the basin so its not double counted),
then "Union" (to determine flooding within the ponds),
then "Select" (which removes the flooding within the pond).
From here I was just going to use a "Calculate Field" Tool since each step has determined the area of the new polygon. Except every time I run the same files it provides a different answer or changes the name which means I have to change my calculate field tool.
I'm trying to automate the process since I need to move onto another project and this needs to be done for twelve flooding events every year.
I've tried using "Add Geometry Attributes" But it always seems to break the model string and keeps giving me the following error "ERROR 000229: The data is not accessible. It is likely either invalid or not available." I usually add this action after "Select" then "Spatial Join" to be able to add a extra fields before "Calculate Field". Sometimes the add geometry works but 90% of the time it doesn't.
I only have access to basic ArcMap which means many of the answers provided for finding area that are similar I don't have access to, (ex, "Difference", or "Raster")