Because tomorrow Friday 2-10-2017 So. Calif. is expecting a large RARE rain storm that will remove signs of people being in high risk "drop" locations, I put in nearly 4 hours of search time along the river averaging 25 feet of eroding banks. I walked every inch from the I-5 freeway crossing to the north/west corner of maintenance property belonging to Magic Mountain 6 flags park including 6 roll-off semi sized containers, all 100+ broken concrete piles. Why? 1 person worked there and another person HAS ALSO WORKED THERE but not sure if currently. I asked a guard where HR was and just prior to walking in, a security car with 3 management types came to talk to me. I gave them all my info. and when asked if they were aware of this case.....of course not, but their people walk where I did for bad water run off to the river. Then how would they know to look for what I am looking for and not leave any shoe impressions where I've been? I drove to just before Valencia Travel Village and previous river access has been fenced off. I drove up Bouquet Cyn. rd. again, but past Vasquez Cyn. turn off where I found lots of trash/furniture and nothing else.