The craws in my pond are the Northern Virile, but they don't burrow. I'm not entirely clear on how they got the reputation for making a pond muddy, but they do. I suspect an over populated stand of them causes them to work the bottom excessively for food. That, and I have aeration which aids in keeping the mud suspended. Wait on them until you have some fish that will keep them in check. On the positive side of too many craws... I'm boiling 200 of them later today.
Add your fhm's now with some floating pallets for them to lay their eggs on.. I would add some foam board to each pallet to keep them floating while your pond fills. Pallets will sink after they saturate. Heck, just some foam board anchored here and there might work by itself.
