River Flow Disagreements

I was running the Sauk River and got into a conversation about the river flow. I had been watching the river flow, and I knew that the flow was dropping, but one person was sure it had come up since the day before. He had convincing evidence - when he ran it the day before, there were rocks that were not covered that were covered the next day. The only problem was that he was wrong. Both of the gauges showed that the river had come down somewhat significantly, and there was no reason to think that the river had come up. It wasn't hotter and the rain had stopped the day before.

I realized that this wasn't an uncommon situation. Many times I've heard people say that a river was higher or lower, and then checking the gauge showed that the flow was unchanged or had changed in the opposite direction. In most cases I can recall, people said that the flow had come up when it had in fact gone down.

A similar discussion came a couple of weeks later, when someone claimed that the Wenatchee had been lower a year earlier. The estimate was that this year the flow was very high, while it had been about 3000 cfs lower the year before. In fact, just the opposite was true.

I believe that this phenomenon is caused by people associating high water with difficulty, while some rivers can actually get easier at some higher flows. Rapids will "wash out" - holes turn into waves, waves stop breaking, and new routes open up that aren't as hard. Another factor is the "fractal" nature of rivers - rivers have similar characteristics as they get larger and smaller.

I've gotten to the point where I no longer argue about it. I just gather the opinions people have and then check out the information available when I get home.