How long after supposedly being hammered, would you give a loch to recover?

Huggy is local to me and apart from the fact that I saw it empty a few years back, TPTB seem to be happier building sandcastles and entertainment centres for birds, than actually managing the loch itself.

Could it be beyond rescue?
Im considering a trip in the inflatable, armed with fish-finder/sonar call it what ye like and live view underwater camera, to have a look at whats happening. Even after it was re-filled I remember seeing carp near the garage, other fish are not so easy to spot, so somebody must have put them there, but what else?

BN