Scenedesmus.
Good thing is, thats a relatively boring green algae that's not generating the nasty toxins that Cyanobacteria do.
If it was a pool/not draining into the Potomac, you could control it w/ a chlorine shock and some copper sulfate. Watch the concentration, it could damage the sides—oh
cpgrouchy
Gift article on the algae in the Reflecting Pool, with a bonus comment from my chemist husband (who has worked with algae in biofuel research)
"Yeah, it's definitely Scenedesmus, most likely Scenedesmus obliquus (possibly some Scenedesmus quadricauda as well)."
www.theatlantic.com/politics/202...
www.theatlantic.com
Testing reveals that efforts to suppress one algal bloom seem to be fueling another.