re: Hypothetically? Is there a way to muffle or silence a 22 rifle?

no, and now it is too late to deal with prior to season being over.

I tried to find the end of pipe in the lake to no avail. I believe the lake finally filled in enough with sediment that the entire pipe including the intake are now under mud.

I tried to shove a push pipe through to the other end to dislodge the obstruction and allow even a small amount of flow which would then hopefully errode the remaining blockage away. I got 130 ft of 1/2 electrical conduit down the pipe until I hit the obstruction but could not dislodge it.

I will have to try again after season.

Did manage to get the 6 acres planted though and now need it to rain (but not too much) so my polt will come in and not wash away due to lake overflow.