Wednesday, October 16, 2013

Let’s talk science: Columbia River holds strong as 2nd largest river in the U.S., if you measure right

By Brook Beeler, communication manager

I think those of us in the Northwest are pretty darn proud of our mighty Columbia River. We boast about many of its facts. At its mouth on the Pacific Ocean the river is known as “the graveyard of the Pacific.” Its scenic gorge was scoured by the Great Missoula Floods. Famed Lewis and Clark explorers camped along its banks among the region’s native peoples. Its drainage basin touches seven states and two provinces, encompassing 258,000 square miles of land -- roughly the size of France.

But is it the second-largest river in the U.S.? An Ecology webpage on coastal erosion touted this claim.

A recent Twitter conversation challenged that fact and prompted an investigation.

As a recovering science major in college, I figured it was simply a matter of metrics. Wikipedia, of course, was my first stop. There the Columbia River ranked out at fourth by volume. Our river was not to be seen second in line for anything!

If the Columbia River was number two, what were the Ecology scientists actually measuring? Was it length, volume, drainage area? I had to find out.

A few emails later I had an answer. Ecology Coastal Monitoring & Analysis Program environmental specialist Diana McCandless shared the following insight:

By volume, inside the U.S., the Columbia River’s mean annual discharge is outranked by:
  • The Mississippi River - 593,000 cubic feet per second.
  • The St. Lawrence River - 348,000 cubic feet per second.
  • The Ohio River - 281,000 cubic feet per second.
  • The Columbia River -265,000 cubic feet per second.
However, our focus at the Southwest Washington Coastal Erosion study is on rivers supplying sediment to ocean beaches, so the statistics we reported on our website is focused on river— mouths. The St. Lawrence River drains northward and its mouth is in Canada, so we nix that from the list. Furthermore, the Ohio River drains into the Mississippi River so that 2-river system has only 1 mouth that outflows an ocean beach. This brings the Columbia up on the list to spot #2 in terms of average annual discharge supplying sediment to ocean beaches in the U.S.

Sometimes science is also art. Rivers don’t necessarily follow our jurisdictional lines. So although it seems to be a technicality, the Columbia River remains at number two with some artistic line drawing.

At any rate, we are still proud of our status and in the words of Woody Guthrie, “Roll On Columbia!”

For more fun like this follow us on Twitter @EcologyWA and more.

Big hat tip to @RachelAronson for inspiration.

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