The permit is for the upkeep of the dam. That's not cheap. There are far more trails around the park that are free. Go park at PetSmart and walk to the trail head.
This facility has been around for decades. I'm glad it isn't that developed and as easily accessed. Humans tend to destroy things. Parts of the trail are free. This part is not. Feel free to use the free parts. Not unfair if you see how beautiful it is and peaceful. No kids. A quiet escape from the rat race.
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