Seems they just need to toss some copper sulfate into the pond to clear up the algae then.
The algae will die out when the nitrogen is used up. Algae and duckweed are nature's little sewage treatment plants, so I'm kind of hesitant to say there is actually anything wrong here, other than the ponds may not look pretty.
If there actually is too much algae in Rock Mountain National Park, my first guess would be to look at sources of nitrogen in the park. The park is upstream from everything, it is on the continental divide, and the water flows out of it, not into it. Guess number one would be that there are too many fish in the lakes and rivers.
Fish known to be native to the area that became Rocky Mountain National Park were cutthroat trout, suckers and sculpins. These fish were only historically found in the lower reaches of what would become the park due to waterfalls and cascades which served as fish migration barriers. Cold water temperatures make it probable that many of the waters in the park were originally fishless.
Rocky Mountain National Park - Fish
But what do I know, I just hang on to the "old school science" where people had theories and tested them.