It is, of course, not algae, but duckweed, and the East Valley Tribute reports that:
An aquatic weed carried downstream by the recent monsoon storms is invading Tempe Town Lake and turning it green. The plant, known as duckweed, does not pose a public health threat. But unless the flow of water from the northern part of the state slows down, the green plant could become an enduring fixture on the lake, city officials said.The article also notes that
Duckweed is a small plant that floats on the water's surface, feeding off nitrogen and phosphorous and can double its biomass within 10 days, according to some reports.So, it is not algae. It still looks like a swamp. My, my, what a mess. Duckweed comes to the lake naturally. It actually kills off algae, which is probably a good thing, but since it also consumes most of the oxygen in the lake, it will eventually kill of the fish.
So unless something is done, the taxpayers of Tempe will have subsidized a large artificial body of water, that is oxygen free and full of rotting fish.
Sure sounds like a swamp to me.
Or, they can apply chemicals (Gasp! The horror of it all!) and end up with a chemically enhanced artificial body of water that may or may not have fish, may or may not have duckweed, and may or may not have algae.
Sounds like a great place for a swim meet. California has the "X" games, maybe Tempe could host the Tempe Toxic Swimfest.