If those guys have been swimming there that long, I have guarded them before.
i'm not saying runoff upstream isn't a problem. It is. But mishatex is correct with his comments about regulations regarding draining, algae, cleaning, etc. Guards clean the pool. They have much less freedom in the manner in which they clean it than when I guarded there. And it's due to new environmental regulations.
And for the record, call the City of Austin Aquatics Dept. The pool is clean and clear. If, in your opinion, it is not as clear as it was 10-15 years ago, I suggest you do more research before labeling the reason "pollution".