California has always had cycles of drought, fires and then flood. Many native plants need that cycle to reproduce. That's also how the streams and rivers get reclassified with gold. Gold panning should be good for a couple years, not like the gold rush though because the streams had numerous cycles to build up deposits before it was discovered. Most of the mountain west is quite the same. Just look where the biggest placer mines were and that will show you where that cycle dominates