I lived in that area in the 60/70’s and as I remember that river was always a hazard—full of ah, sewage. The river passes through Tijuana then north across the border and along the border out to the sea. So in the 60’s the US, maybe California, build a sewage plant for them.
That was just one of the absurdities of the EPA under Clinton. There also was an instance when a new hospital was proposed in LA. There was a suit claiming that the land proposed for the hospital was a potential habitat for some sand fly. None had been seen on the property but it looked like other property that had sand flies. The hospital had to buy additional land that would be designated as sand fly habitat.
Here’s the funny part. Since there was no sand flies on this property, the EPA wanted to designate a “sand fly flyway” connecting the property were sand flies were present and the new sand fly habitat. The flyway was to be 100 feet wide and extend from ground level to 200 feet altitude and a couple of miles long. The proposed route for the flyway made three right angle turns and crossed the 405. How the sand flies were to be notified of the directional changes was not specified. However, the EPA proposed lowering the speed limit on the 405 where the fly way crossed to 5 MPH.
The fly way was so ludicrous that it was removed from the settlement.