Negitive total volume calculation

Hi, can anyone tell me what is going on here, I am trying to do a volume calculation on a gypsum dune in a lake system that has water all around the area that I am trying to calculate.
I have split the dune into 4 sections 3 of the areas have a positive volume total and 1 is a negative total volume, I don’t understand what is going on here can anybody help?

The Green area is 7400 cube meters and
the red area is saying -10726 cubic meters

Hi @trags - negative volume means that the area has a higher cut than fill. We have some more explanation of this here;

Please check that out and send us an email to with further questions as well as the name of the map if you’re looking for further information.