Dr. M. Kamiar is a Professor Emeritus of geography at Florida State College at Jacksonville and for decades he found himself continually correcting his students when they parroted the phrase, "the St. Johns River and the Nile River are the only two rivers in the world that flow north." In this editorial he explains that there are hundreds of rivers that flow north and; in fact, the St. Johns River flows south as well.
The orientation of the St. Johns River is not an exception to natural laws. It is rather an illustration of nature’s efficiency. More than 100,000 years ago, most of the land that now is occupied by the St. Johns River basin was an arm of the Atlantic Ocean. The river itself was a part of an extended system of bays, inlets, lagoons, lakes, and tributaries. The separation started during the last ice age, about 15,000-20,000 years ago, when Florida was almost 2.5 times larger than today.
The St. Johns River has a very gentle slope. The elevation near its origin in the marshes of central Florida is about 30 feet. St. Johns River’s gradient is one inch per mile. This drop over the river’s 310-mile course makes it one of the slowest moving rivers in the world. This, coupled with Florida’s Karst system of sinkholes and other geomorphological factors, has made a river that has many lakes along its course.
The St. Johns is a non-alluvial river. It does not erode its banks and channels, due to its gentle slope. And because Florida is mostly flat, the St. Johns River is very wide. For a good part of its length, the river is about 3 kilometers wide, far wider than the lower Mississippi River.
Many large rivers in the world, when they empty their waters in the oceans, change the temperature, salinity, and the color of these bodies of water. The fresh water of the Amazon penetrates into the Atlantic Ocean up to 200 miles. Yet, in the delta of the St. Johns River, especially in periods of low rainfall, tides may cause a reverse flow as far south as Lake Monroe, nearly 160 miles upstream.
The St. Johns, far from being the only U.S. river to flow north, isn’t even the only Florida river to do so. The Withlacoochee River flows north. But determining the precise number of north-flowing rivers isn’t a simple task. A researcher for the allexperts.com website named Thomas Baglin, using Mapquest and Mappoint, found 48 rivers in 16 states that flow north, most in Alaska (9), Washington (8), and New York (6). For some reason, he did not list Florida’s two northerly running rivers. But if included, the U.S. total increases to 50.
Matt Rosenberg, a geography “guide” at About.com, pointed out that “there are countless examples of rivers flowing northward.” He provides a list that includes those above along with Russia's Ob, Lena, and Yenisey Rivers, Canada’s Mackenzie River, and California's San Joaquin River.
Michael Onken, a Washington University graduate student who has researched north-flowing rivers, offers eight more: from Europe, the Rhine, Elba, Oder, and Vistula flow mostly northward through Germany and Poland; from Canada, the Athabasca; from South America, the Araguaia, Xingu, and Tapajos. More importantly, he argues that “over two thirds [almost 70%] of the rivers of Brazil and Bolivia flow North through the Amazon rainforest.”
L.A. Fundis, a reference librarian in West Virginia who runs a website called “Rivers that Flow North,” identified a total 117 rivers that flow north in the world -- 51 in the U.S. Using the National Geographic Society’s and Wikipedia’s online excellent color-maps, I came up with a rough estimate of the number of rivers that flow north. That tally of 245 rivers is a conservative and rough estimate.
The world’s largest north-flowing rivers are found in the remote regions of Siberia and the Amazon and Congo Basins. For example, the Yenisey, the largest river that flows north in Siberia, is even longer and more voluminous than the Mississippi. I have no doubt that most people will be surprised to learn that there are more rivers in the world running north than in any other direction.
Dr. M. Kamiar is a Professor Emeritus of geography at Florida State College at Jacksonville. He can be reached at firstname.lastname@example.org.