I'd see if you can pick up 200-400 pounds of bentonite and spread it over the rock that is exposed, making a "cap" of bentonite over the rock, and incorporating it into the soil immediately surrounding the rock. For what bentonite costs, it's cheap insurance if the pond is thinking about leaking at the rock.....
Throw it in the back of the Ranger and see if you can get it spread out over the rock before the rain. You might have more water coming into the pond than you think.....
