How to Read and Understand River Levels on the Columbia – Part 1

The Columbia River, despite having been “tamed” by the dams is still a dynamic river.  Even those sections that seem more “lake-like” are still very much in a state of constant change.  There is a way to stay on top of those changes and with a little practice, you can get instant access to what the Columbia is doing.  Combine that with some basic note taking or logging and you can begin to make sense of what water levels and river flows are most productive or at least not get caught by surprise when you show up at the ramp.

A Base Line Website

The Army Corps of Engineers (Walla Walla District) is my everyday, base website that I use.  From here, I can access daily (hourly) and/or monthly stats at the various dams.

Making Sense of the Numbers

Now, the next step is interpreting what I’m looking at.  Over time you will be able to determine what “normal” is and what numbers correlate with the river being “high” or “low”.

The two columns I pay the most attention to are “Total Outflow” and “Forebay Elevation”.  At McNary, I know that 338.5 for Forebay Elevation is pretty normal.  Less than that, is low water, more than that I consider on the high side.  In more general terms:




There is a little more to it than this, but you get the idea.  We’ll get into some more details later.  Now, on to “outflow”


If I want to know what the current/water levels/water clarity is like below McNary, then I pay attention to the outflow or “Total Outflow”.  Again it helps to know what “normal” is, so I either have to pay attention to those numbers over time, or compare what I’m seeing on the water to what the website is telling me.

Monthly reports help me understand trends and what the new normal is. I can compare these numbers to those from past years and get a sense for how my outing today will be compared with my trip(s) last year at this time.

You can pull up historical data (below) for comparisons.

2016 was a much different year than 2017. How different? Compare numbers below to current numbers at each of the dams.

I can compare current outflow numbers from above with what other years were like for comparison.

Next time, we’ll look at how to different sections of a pool are impacted by what the upriver and downriver dams are doing.

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