Thanks to all of you for your helpful replies. My goals for the pond are: 1) clearer water for swimming, 2) less rooted plant growth in the middle of the pond (I don't mind cattails or water lilies around the edges). I am happy to provide a fish habitat, but I don't fish. So, fish production is not a priority. (I understand this may be considered sacreligious by many readers.)
Let me add more detail on the pond. It was created about 60 years ago when a causeway was built across the creek, flooding the valley to a depth of 20 feet. I doubt anyone other than mother nature has done anything to this pond until now. There is about 6 inches of muck on the bottom around the edges. I couldn't guess how deep the muck is on the very bottom. Lots of leaves, pine needles and wild apples fall in the pond, plus the pondweed and cattails add to the mix.
My desire for balance between water clarity and natural conditions comes for several reasons: 1) I visit this pond on weekends--I don't want to become a slave to it nor can I entertain a constant labor intensive program, 2) I enjoy the nature it attracts (heron, muskrat, cormorant, etc.) and 3) the pond is within the UNESCO recognized Niagara Escarpment Biosphere Reserve, which means I am limited in the range of solutions I can consider (e.g., I cannot significantly disturb the condition of the water downstream--no chemicals, I cannot drain it and scrape out the muck without a permit, etc.).
I suspect from the replies above, I may already be as close to my goals as I can get.
If some form of rooted plant growth is inevitable (and desirable) then I would prefer vegetation around the edges, rather than in the middle where during the summer it makes the pond look like it has stagnated (at least to the untrained eye). If I could encourage mother nature in this direction, I would consider this a small success.
I would be interested in the options I have, given my limitations, to increase the water clarity.
