We get used to seeing rivers and creeks within the confines of their banks. In the peak of our bone-dry summers, it’s hard to picture Camp Polk Meadow under water. On a tour I took this summer, I stared at a dry side channel thinking, “when is there ever enough water in Whychus Creek to spill into this spur?”
That answer came last month, when Whychus Creek swelled to 1500 cubic feet per second (cfs), one of the highest flows we’ve seen in years. On December 23, 2014 there was more than 10 times as much water flowing through Whychus Creek than there would be on a typical winter day.
I turned to our resident amateur meteorologist and associate director, Zak Boone, for a look at what caused the flood. A December rainstorm, originally forecasted to hit north of us, brought heavy rainfall over a short period of time between Mt. Jefferson and Mt. Bachelor. The rain came so quickly that the ground was not able to absorb it, particularly in areas affected by the Pole Creek fire of 2012. Much of this area drains into Whychus Creek, causing exceptionally high flows downstream. Had there been significant snow in these areas, or had the rainfall lasted for multiple days, the overall flood could have been much more dramatic.
Nonetheless, it was one of the biggest floods at Camp Polk Meadow that we’ve seen since Whychus Creek was reunited with its meandering historic channel in 2012.
On Whychus Creek, meadows like the one at Camp Polk are rare. They provide much needed opportunities for Whychus Creek to overflow its channel, slow down, spread out, and seep into the soil. Camp Polk Meadow acts as a sponge, absorbing and slowing the creek, while allowing bits of dirt and rock caught in the current to settle. This benefits the overall water quality of Whychus Creek.
In the popular media, we often hear about the destructive forces of flooding. But to see the big picture, we also need to think about the benefits of natural floods. Floods create some of the most fertile land and rich habitat in the world. In our high desert, lush meadows like Camp Polk Meadow are uncommon habitat hotspots for a diversity of wildlife. Floods benefit soils, add moisture to creekside plants, and bring more of the gravels that native fish need to spawn and reproduce.
In short, we were excited to watch Camp Polk Meadow flood. Those who worked on the project were thrilled with the way the stream channel allowed Whychus Creek to spill onto the floodplain and move around the meadow as it should.
According to the experts, Whychus Creek at Camp Polk Meadow keeps getting better with each flood. And that’s encouraging to see as we continue our work to chart a better future for Whychus Creek.
See more images of the flood and Camp Polk Meadow Preserve in the slideshow below (click here if the images don't appear). You can also see video footage of the flood on our Facebook page.