I have several depressions in my back yard that each year get deeper.
Some of the property was filled so I am assuming that the home builder
(house is about 18 years old) buried stumps. Aside from time or
digging them up, is there anything I can do about this? Is there a way
to accelerate the decomposition of the stumps? How long does it take
stumps to rot?

George

I have that too. I need to order another truck of top soil.

Well, you could get someone to plow and harrow your lawn,
and then re-sod. That would probably do it. Where are
your water, power, gas, and sewage lines?