Ranking Rivers
It's high tourist season in Alaska again, and just about every visitor wants facts and tales to take home with more concrete souvenirs. After they've heard the bear stories and memorized Mt. McKinley's height--and maybe even learned why we call it Denali---what can you tell them? Bring on the rivers. After all, tourists like superlatives.
The Water Resources Division of the U.S. Geological Survey has a handy fact sheet (and considerable authority) useful for the purpose. Of their list of the 32 largest rivers in the United States, considering volume of water discharged, size of area drained, or length, Alaska has eight. That's--of course--far more than any other state can claim, and twice as many as Texas has.
To be fair, the USGS list attributes rivers to the states containing the river's mouth. Thus, Alaska rivers get credit for a lot of Canadian water and territory, but then Kentucky gets credited with the Tennessee River, which begins in North Carolina.
So, with understood thanks to Canada, we can begin with our mightiest river in all categories. The Yukon is the nation's third longest river; at 1,980 official miles from its source in the Nisutlin River of the Yukon Territory to its mouth in the Bering Sea, it is outstretched only by the Missouri (2,540 miles) and the Mississippi (2,350 miles). In both average discharge at mouth (225,000 cubic feet of water a second) and drainage area (328,000 square miles), the Yukon River ranks fifth nationally. For comparison, that's right ahead of the Columbia in area drained and right after it in discharge. (The Columbia River also needs Canada to gain its rank; its source is in British Columbia.)
Two Yukon tributaries also make the list. The Porcupine ranks 20th in drainage area, and the Tanana is number 16 for average discharge. The Tanana is one of four rivers on the USGS list that starts where a glacier ends; its official beginning, with the Nabesna River, is in meltwater from the Nabesna Glacier, 659 miles from its mouth. (I'm sorry to say that makes it the third-longest river on the list that starts and ends within one state. Longest is the Colorado River of Texas, which wanders 862 miles in our second-largest state.)
Another listed river starting at a glacier is the Susitna, which gathers enough water from the Susitna Glacier and its tributary streams to achieve 15th rank in discharge---51,000 cubic feet each second on average. Southcentral's other listed river is the Copper, 10th in volume of discharge, which begins in the Copper Glacier. Probably most Alaskan-sounding of all is the Kuskokwim, ninth in discharge, 17th in drainage area, and second-longest river within a single state at 724 miles. Its source is given as "South Fork Kuskokwim River at terminus of unnamed glacier." At least that lets us brag that Alaska has so many glaciers we haven't got around to labeling them all on the map. Texas can't top that one.
The Stikine takes honors in Southeastern. Its 56,000 cubic feet of water discharged to the sea every second gives it 13th rank in the category. The last of Alaska's rivers to make the list is the Nushagak, with 20th place in volume for the 36,000 cubic feet of water it discharges into Bristol Bay each second.
It's a good showing, but if the USGS had been a little more imaginative in its categories, Alaska might have done even better. If there were something called "amount of discharge in solid form," for example, I suspect the Yukon's ability to send ice downstream would put it first. And certainly a "ratio of fish to water, by volume" category would see the Susitna and Nushagak right up there at the top. That's the kind of statistic the tourists would really love.
