Just adding a note on eutrophication from one of my ponds.

We had a hundred year old groundwater pond at our farm that had been slowly filling with sediment and leaves. The 2-year drought in our area had dropped the groundwater level in the area BELOW the bottom of the pond. The pond essentially looked like a marsh with zero standing water, but heavy plant cover in the damp mud.

I dug the pond about 8' deeper this fall and got the bottom back below the groundwater level. The pond then re-filled with beautiful, clear groundwater for our wildlife to utilize this winter.

I went by the pond on March 5th to see how it was doing. Still had beautiful clear water, but it was a fairyland of filamentous algae! There was lots of algae that had started on the bottom and had even established a few floating mats, with tendrils of algae connecting the two.

When I dug out the pond with the excavator, I certainly went deep enough to remove all of the rooted plants. I don't know where the initial algae starter cells came from, but the FA is essentially the only thing in the pond that is currently utilizing all of the accumulated nutrients. The pond is partially shaded, and we haven't yet had that many warm days, but the FA has already kicked into high gear!

(I just added this off topic note, because the pond was kind of an unusual "experiment" compared to the more typical ponds on the forum.)