Does anyone have a rainwater/drain Tunnel Legend for the valley?

As the title says I’m looking to find a legend/map for the tunnel systems in the valley. I’ve gotten a little bit into urban exploration in the area and know a handful of spots, but I specifically enjoy checking out the tunnels! I mostly just want to see what’s underneath us and have a better idea of what all/how far they go! My normal searches have few results (except purchasing a map for $40 if your a government entity or utility worker haha) so anything helps :)