Tom, OK, five years it is then.
While the overall depth of 38' may be unusable for most fish, others here have done nice things with making islands and humps on the bottoms of deeper areas that will come up to more shallow depths. These become fish attracting areas.
I think another benefit is that all the earth does not have to be "removed," just moved into piles. This benefit has been stated by others.
There might be some kinds of desireable fish that could utilize that deeper water.
