I want to generate a flood plain for a river in ArcMap. Basically, this means that I want to create polygons with certain elevations above the drainage point elevation (870 m).

For instance, I would like to make a polygon that has an elevation of 872 m, intersect that polygon with the surface tin which would give me an idea of the flood plain if the water level was two meters above the drainage point.

1 Answer 1


Worked it out, I just drew a polygon around the catchment, added a field called HEIGHT, and then used the field calculator to give me the height I wanted (872m). I then generated a tin from that polygon and then used the surface difference function with the reference surface being the tin I created from the contours to find out where the new tin was above, below or equal.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.