Lakes and rivers often suffer a "tragedy of the commons" problem. Being these water bodies are typically public property, they don't obtain the care which they would receive if privately owned.
A good group to follow on this topic is PERC, go to http://www.perc.org
I started this section here for the benefit of other Libertarian candidates in New York state. See also the section on DEP (Department of Environmental Police) for similar discussions.
Here is a report on a lake management strategy for Chautauqua Lake in western NY: