It's a real pretty pond. If it's three feet low, then your depth will be fine when it fills up again. They said they cought a big fish in it already, so it sounds like it's already in ideal condition for fishing.
I'd be very, very careful about making any changes to it. You very well might have the perfect fishing hole already. Draining it and digging it up sounds like a good way to spend tens of thousands of dollars just to set you back ten years in what the pond is already producing.
I wouldn't even think about having any dirt work done to it. If you absolutely feel that sometime down the road you need more depth, then look into building up the dam. Draining and cleaning up the silt is very time consuming and EXTREMLY expensive. That wet silt takes a year to dry and even then, it's still gonna have pockets of muck that will swollow a tractor.
Killing the alge might also kill off a very good source of nutrients for your feeder fish. It's ugly, but some alge is very good to have.
I think you should consider a very mild and controled attack on lowering the amount of alge to a point you can live with it and then start fishing it to see what's in there.
Don't do anything else for at least a few years.
You really need to know for sure what you have there and what you might be destroying if you start working on it.
Contrats and good luck,
Eddie
