My 1 acre pond is along the Clackamas River near Oregon City. There are lots of geese & ducks on the pond and trees around the pond. How do I prevent the big algae blooms that cover the pond without using chemicals? It might be 4-6 feet deep.
This is outside my expertise, but some contributing factors to the algal blooms could be warm water and high nutrient load. If the pond can be shaded, and if you can ensure that plant nutrients (fertilizers, manure, etc.) aren't getting into the pond, I expect algae would become less of a problem. Duck and goose manure could be contributing to the problem.
This Washington Department of Ecology site appears to have some good information: http://www.ecy.wa.gov/programs/wq/plants/algae/lakes/ControlOptions.html
I also suggest contacting Derek Godwin at OSU. I think he is more knowledgeable on this topic: email@example.com.