I have had some questions as to the relationship between flows and returning salmon which is different in tidewater than flowing streams. The flow thing is complicated yet simple. Flows are about cubic feet per second (CFS) which is 7.48 gallons in a cubic foot per second. So the difference between 100 cfs and 200 cfs for Chehalis Basin flows is not that huge. What is hidden in that number is water temperature and dissolved oxygen (DO) which are rather important. Warm water and low DO stress the heck out of returning salmon especially above tidewater.

Tidewater is not about flows as tidewater is measured in acre feet and an acre foot one foot deep is 326,000 gallons. So in tidewater the flows are important but seldom a driver for salmon behavior and health until a real bump in flows or the fall rains water up spawning streams. In times such as the present it is not unusual to see the same log float up and down the river with the tide day after day. I have always thought of it as a bubble of fresh water moving back and forth. Think of it this way if you put a barrier across the bay and drained the bay how long would it take to fill the bay and tidewater. Looking at tidewater and bay acre feet and summer cfs flows coming into this area many months or even years.

Salmon always do the same thing each fall but differently. They come out of the ocean to be sure and that is the only thing that remains constant. They will hold in the bay, swim right through tidewater, or stop in tidewater, move out of tidewater into tributaries, and in the Chehalis itself move above tidewater but seldom above Porter minus substantial rain. The combinations of these factors are many and coupled with behavior such as last year simply move in mass upstream way early makes predicting what salmon runs are doing is next to impossible before it rains.

The one constant behavior always present is after leaving the ocean and entering the bay the vast majority of salmon will stop and wait for rain someplace out of tidewater, which is known as staging up. The best example I can provide folks is the East Fork Satsop Coho. Many years broodstocking Chinook the hatchery Coho were stacked below and well above Schaffer Park yet Bingham hatchery a few miles away had very few Coho if any to the trap. Yes you have the outlier years such as last year but those years are few and far between. In the hatchery returns in the 80s and 90s we had as many staged Coho red fish return as anything silver looking with the Humptulips Hatchery being almost the opposite.

The one thing that we learned on the East Fork Satsop was Coho stay staged (mostly) until it rains but most importantly spawning areas water up. On the East Fork it takes a descent amount of rain to water up but when it does the first thing that happens is brackish black water comes down stream and it is almost a golden black color. The fish would crowd into areas out of the main current and as soon as the brownish water arrived off they went like it was a race, which in terms of spawning I think it is!

So for the harvest managers freshwater fisheries are always a bit of crap shoot. Often they get it right and sometimes like last year they get it wrong. With the predicted weather pattern being dry and salmon behavior almost completely unpredictable, who knows what the next few weeks have in store for us. My thought is fish when you can as planning ahead is likely not going work out well.