The free-flowing Mattole River, running 62 miles from its headwaters in Northern Mendocino County to its mouth, five miles past Petrolia in Humboldt County, defines the wettest place in California. Lauren Schmitt of KMUD radio went to Whitethorn, near the headwaters, to check in with the Sanctuary Forest land trust to find out how the river and the fish that spawn there, were affected by last month’s deluge.