possible contaminated water dumping into Alamo river

On Monday as drove on Orchard noticed a big puddle of green stagnant water on grassy east side of bridge. On Tuesday my son and I walk the trail and observed a box set as a way to make water flow down towards trail then downwards into Alamo river. (Man made diversion) You must have a permit to dump into a waterway! What was dumped into that river, was green and stagnant!