CLAIM TO FAME: Motorists driving through Potter County might see a little dribble of water in a field, and a nearby marker proclaiming it as the headwaters of the Allegheny River. But now we have an even bigger question: Is that rivlet in Potter County the start of the largest river in North America?

      Network Notes, the newsletter of the Pennsylvania Environmental Council's Allegheny Watershed Network, asks: "Does the Allegheny flow past New Orleans? (Or does the Mississippi flow through Pittsburgh?)"

      Here's what Gary Fleeger of the Pennsylvania Department of Conservation and Natural Resources has to say:

      "Look at a map of the United States and you will see the Mississippi River flowing from Lake Itasca in northern Minnesota to the Gulf of Mexico below New Orleans.

      "The Ohio River starts at the confluence of the Monongahela and Allegheny rivers in Pittsburgh and flows into the Mississippi River at Cairo, Illinois. But, is that correct?

      "Is the Ohio a tributary of the Mississippi, or vice versa?

      "Where two rivers join, how is it determined which is the trunk, and which is the tributary?

      "As mentioned in the PBS series, 'On the Waterway,' many people from Pittsburgh to Cairo believe the Ohio River makes a bend to the south at Cairo and continues on to New Orleans. Which river, the Ohio or the Mississippi, is the trunk at Cairo and which is the tributary?

      "Webster's Ninth New Collegiate Dictionary defines tributary as 'a stream feeding a larger stream or lake.' At Cairo, the flow in the Mississippi River at 228,490 cubic feet per second is only about two thirds the flow of the Ohio River at 322,461 cubic feet per second. The Ohio is clearly the main river and the upper Mississippi is the tributary.

      "It appears that the river that empties into the Gulf of Mexico below New Orleans is not the Mississippi, but is it the Ohio River?

      "The same maps that show the Mississippi River passing New Orleans will also show the Ohio beginning at Point State Park in Pittsburgh, at the confluence of the Allegheny and Monongahela rivers.

      "Why is neither the Allegheny nor Monongahela considered the upstream extension of the Ohio?

      "The Indians and the French considered the Allegheny and Ohio to be the same river, with the Monongahela a tributary. The French applied a single name, 'LaBelle Riviere' to the combined Allegheny-Ohio.

      "Applying Webster's definition for determining trunk and tributary at a confluence, as we did for the Ohio-Mississippi at Cairo, the French appear to be correct.

      "The Allegheny is the larger of the two rivers at the Point, with a mean discharge of 20,000 cubic feet per second versus 12,000 cubic feet per second for the Monongahela.

      The Allegheny-Ohio-lower Mississippi river is a single 2,266-mile-long river!

      "...The general southwestern orientation of the Allegheny and Ohio rivers also suggests that they are the same stream. The Monongahela, on the other hand, flows north to its confluence with the Allegheny-Ohio.

      "Why the three segments of the river were given different names is unclear. What is clear, is that the largest river in North America starts as a tiny rivlet in Potter County, Pa."