Are there carp just below the dam? Smallmouth stream habitat as I know it (might be different farther north) is typically relatively fast-moving water with a gravel or cobble substrate. No doubt that Asians can invade lake habitats that are frequented by smallmouth, but I don't worry much about the smallmouth streams in Missouri. Not that the odd bighead aor silver carp may not make it up there, or that juveniles won't move into the area. But I don't see them doing much in the way of habitat modification in the smallmouth streams I know. I don't think that the amount of filterable material in the water is that good of an indicator of where the fish will show up - they can eat other things if they need to, including detritus, and during periods when plankton populations are up, they will switch back to plankton. But they don't like to live in places where they can't get out of the current most of the time. Put it this way - bighead and silver carp are MOSTLY big water fish. I have seena fewsubadult bighead carp 50 km from any big water, in habitats that are more suited to smallmouth bass. I have, rarely,heard reports of large numbers offingerling carp in similar situations. Ithink, but cannot guarantee, that they are not likely to have substantial environmental impacts in that kind of environment. If your system is haslarge amounts ofdeep slowmoving water, all bets are off.