Make lakes/rivers unusable for popular recreational activities

Some harmful, non-native species, particularly plants like hydrilla and water hyacinth are so detrimental that they completely cover the waters they invade. Waters become so choked with these non-native plants that it is practically impossible to get a boat through and there is no open water left for swimmers to enjoy. Other nuisance species such as zebra mussels leave sharp-edged shells along swimming beaches that can be a hazard to unprotected feet.