In 1980, my 10th season on a tree planting crew in Oregon, a buddy and I were camped on the Elk River at a USFS campground, while our crew was working on units in the Sixes River drainage.
In the middle of our contract we had a “Pineapple Express” weather event — rain so heavy that we didn’t go out for 3 days! When we went back to work, the Sixes was so high that it came within a foot of the bridge we had to cross on our way in and it looked like coffee with cream.
On our way out that evening the river had dropped about 3 feet — still dark. At our campsite the Elk was still rising and we had to move a sweat lodge that we had on a flat rock near the river.
The next morning the Sixes was still dark, but nearly back to “normal,” where it had been when we had started working 10 days earlier. And on the way out that evening it was a little cloudy, but looked like it was back to its original flow.
Back at our camp, the Elk had risen above the flat rock, but was still running clear and it didn’t drop below that rock for the next 8 days!
This rain event was pretty uniform, from the Cali border to Coos Bay. When I looked at a map it showed the 2 rivers had about equal size drainage areas. The biggest difference was in the degree of development: the Sixes has more ag in the lower stretches and less than 40% unlogged timberlands at that time. The Elk was mostly inside the national forest and still had above 75% of its forests intact.
When it rains on a clear-cut, the needle sponge soil gets hammered down until the rain begins to run off, or soak through to the soil layer and run off there.
In the standing forest, the canopy keeps the rain from hitting the ground and when it gets there, it gets soaked into that spongy "needle/duff” soil, and slowly bleeds into the downslope streams.
What this means to the fish, especially those big-bodied chinook, is that they have a much longer “window” to get upstream and into the places that they intend to spawn. That means larger fish have the water volume — and time — to get back to their stream so the advantage for spawning doesn’t begin to favor the smaller fish and restrict the big fish to the bigger streams and rivers only.
Predation on eggs and baby salmon is much heavier in the bigger streams. Chinook babies head downstream after they hatch but coho babies run upstream after hatching out and get bigger before they head downstream. When there were more wetlands and beaver ponds it was better for those little silvers to have places to grow.
Anyhow, chinook salmon are not coming back anytime soon, until there’s enough forest cover to keep the rivers clean and higher, longer, after the rains.