Kitsap rains: not too much, not too little for salmon and aquifers

The on-and-off rains over the past two weeks are nearly perfect for both spawning salmon and for recharging shallow groundwater supplies, experts say.

Chum salmon in Chico Creek. Kitsap Sun photo
Chum salmon in Chico Creek.
Kitsap Sun photo

For October, total rainfall ranges from about 5 inches at Hansville to 12 inches at Holly, according to rain gauges managed by the Kitsap Public Utility District. Fortunately, those rains have not been delivered to us in only a few days.

The intermittent nature of October rains has allowed the streams to maintain their flows without flooding. They’ve also allowed infiltration into the ground without excessive runoff.

“It is the good kind of rain,” said Bob Hunter, interim manager of Kitsap PUD. “We’ve had a couple of days when we’ve had 2-plus inches, but we haven’t seen the streams flash.”

In other words, the streams have not risen excessively fast. Bob attributes that to how dry the ground was before the rains began. Soils were able to absorb much of the early rainfall before stormwater runoff began to increase. Pauses between the rainstorms allowed more of the water to soak into the ground.

“It just goes to show you the variability that we have around here,” Bob told me.

October marks the beginning of the 2015 “water year.” Although we are just a month into the start of the year, the rainfall has been closely tracking all-time highs at some rain gauges — including Holly, which has been monitored since 1999. (See charts below.)

Meanwhile, the rain pattern in October was nearly perfect for salmon, said Jon Oleyar of the Suquamish Tribe, who walks the East Kitsap streams to count migrating salmon as they arrive.

“It seems like we’ve had storms coming in every couple of days, so they are not right on top of each other,” Jon said. “That gives the streams some time to recede.”

When there is not adequate flow, the salmon often wait for the streams to rise. On the other hand, too much flow can wash salmon eggs out of the streambed.

Last week’s rains got the chum salmon moving into most of the East Kitsap streams, Jon told me.

“I checked Chico Creek on Wednesday, and there were almost 11,000 fish in there and going up about as far as they can get,” he said.

A good escapement for the Chico Creek system is between 12,000 and 15,000 chum, and there is still more than a month left — assuming a typical timing of the run, he said. But things are looking a little different this year, he noted, and the bulk of the run may have arrived already.

One indication that timing could be different this year is that Gorst Creek already has a fair number of chum salmon — perhaps 500 — yet the Gorst Creek run usually comes in later and continues well into December.

Is it possible that all or most of the salmon runs are coming in early? It’s a question that only time will answer.

Jon told me that he’s a bit water-logged at the moment, trying to count fish in the rain with the streams running high.

“I’m pretty happy about it,” Jon said. “I have my fish up where they need to be, but it’s just hard to count them right now. If you’re a fish, this is really working for you.”

In the charts below, found on the Kitsap PUD’s website, you can see that October’s rainfall has been tracking the record high rainfall at these stations. Of course, the “water year” has barely begun, so anything can happen. (Click on images to enlarge.)

Rain-Holly

Rain-CK

Rain-Hansville

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