my family farms the ground above the dam. manure was applied to the field a year or two prior to the winterkill problems.that is the most likely source of the nutrient problem even though the water must flow through about 100 yards of grass before reaching the water.

About the same time prior to the winterkills we had a lot of muskrats inhabiting the area. They completely eliminated the cattails that surrounded our shore line could that have contributed to a release of nutrients?

We probably do need to take more steps to filter the water that runs in. But I am wondering how to take care of the nutrients that have already made it in.

We have not tested our water. We are assuming that it is nutrient problem due to the type of dam (very little topsoil was removed during construction) and the watershed coming from agricultural ground.

Likewise we have done no clarity tests. All we have had is our local watershed manager use a meter to test DO oxygen levels After we thought we had done avoid job of keeping the ice clear. He found DO under under 1 at about 12 ft if I remember correctly. The pH at that time was above neutral. I can't remember what it was for certain.

There I quite a bit of weed growth in the shallow areas. All submergent. I trapped most all of the muskrats but cattails are slow to recover.

Clarity has seemed to gone down considerably since the problem started. But as I said we have not tested it to give a score.