Watching streams to see how salmon respond
November 18th, 2009 by cdunaganI often play a guessing game that involves rainfall and streamflows: Are we getting the right amount of rain to help our salmon, or are the rains causing streamflows to be too high or too low?
A coho salmon tries to leap into a culvert against the rushing water in a stream above Wildcat Lake Kitsap Sun photo by Meegan M. Reid
It is easy to come up with an answer when we’ve had hardly any rain. The streams are running low; salmon are ready to swim upstream; and fish in the stream are obviously struggling through shallow water. We’ve seen this kind of condition in early fall during many recent years.
When can we say we’ve had enough rain? Well, certainly when a wide variety of streams and rivers are flooding over their banks. But because of the complexity of natural systems, there may never be a “just right” level for salmon.
I was up above Wildcat Lake in Central Kitsap yesterday, discussing the conditions with Jon Oleyar, a biologist for the Suquamish Tribe. Thanks to recent rains, coho salmon are well distributed throughout the Chico Creek watershed, which includes Wildcat Lake.
Jon was excited to find coho far up in streams where he has rarely if ever seen them. The bad news was, for the stream we were watching, the fish seemed to be blocked by a perched culvert where water was gushing out — a culvert that kept the fish from reaching a beautiful stream with overhanging vegetation and plenty of spawning gravel.
Apparently, few fish have made it upstream of this culvert, Oleyar said, because he has never seen a dead salmon on the other side of the road. And while it was exciting to see large salmon get this far upstream, it was disappointing to find their path blocked.
“I had a smile on my face until I realized they couldn’t get through,” Jon told me, and I quoted him in a story I wrote for today’s Kitsap Sun.
For these coho, heavy rains of the past few days have brought them to new habitat. Yet the flows through the pipe have kept them from going any farther. I will watch as the flows drop over time to see if there is a level that allows them to swim through — although they will need to leap up into the culvert to do so.
Meanwhile, the main channel of Chico Creek, five miles downstream, was flowing high and fast, although it wasn’t flooding. I’m not sure if this is good or bad.
Rocks and log weirs, which can be obstacles at low flow, were now submerged, presenting no obstacle at all. On the other hand, resting pools were gone, and salmon were fighting the current and probably using up their energy. Was the flow high enough to wash salmon eggs out of the gravel? I don’t have a clue.
It is easy to see why biologists talk about the value of “structure” in the streams. Fallen trees normally don’t block the entire stream. Even when they do, it is just a short time before the force of the water creates openings for salmon to swim through. Beneficiallly, extensive “structure” creates pools for salmon to rest and hide, no matter how high the flows may be.
The answer to the question of “too much or too little rain?” seems to vary from stream to stream and even upstream and downstream in the same watershed. It is interesting to observe a stream over time to see how streamflows respond to various rates of rainfall and how salmon respond to various rates of flow.
For Kitsap County residents, we have produced an interactive map on the Kitsap Sun Web site that shows where one may look for salmon. Not all the locations have salmon at the same time, but it may be worth a look.
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Tags: coho salmon, Wildcat Lake
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November 18th, 2009 at 8:53 pm
It is interesting to me to hear that Jon Oleyar (the Suquamish Tribe) is concerned about fish passage at that culvert. It must also take the smile from his face every time he drives down Bond Road in Poulsbo past the dam the the Suquamish Tribe put in and past the two other dams they have used on that property. I believe these three barriers pretty much stop fish from all the spawning grounds above them. I have personaly seen over 100 fish just hanging out below one of them. I am sure that they must be already working on the plan on removing them. “Lets remove the dams from Dog Fish Creek”
November 20th, 2009 at 11:45 am
Emil, I welcome your concern and appreciation of Kitsap salmon. Funny you should mention Dogfish Creek, as a recent stream survey of that stream proved very insightful. As there were not many fish overall (to be expected in a low return year as this one), there were fish in-stream nonetheless (which did put a smile upon my face).
To you specific concern regarding the “dam strucuture” on the Bond Rd fork of Dogfish Cr – it may be a slight slowdown for fish, but definitely not a passage blockage as you seem to illustrate. In fact, fish were observed distributed well upstream of this location. Some years low flows may slow fish passing at this location, as seems to be the case in every stream under those conditions.
If you are looking to “fix” Dogfish Creek passage problems, I could steer you towards many other more impeding locations well downstream. We could start by removing all fencing which crosses the creek, as these are often washed into the channel during high water events and ultimately end up entangling fish and other creatures. Down fences catch much debris and begin to create dam barriers which fish cannot navigate through and tend to cause local flooding if not attended to. So perhaps we should focus first on cleaning up our precious streams of harmful debris and litter left behind by us.