Episode 47
Copyright © John Page Williams, Jr. all rights reserved.
This is John Page Williams with another reading from my Chesapeake Almanac. This entry is from the month of March and it's titled "Some River Geography."
March is a good time of year to think about rivers. They warm up faster than the main Bay. Animals in them are already stirring around. By the end of the month the first of the river herring will be coming up from the Bay and the ocean.
This is also generally a wet month. Spring rains begin. The rivers and the rainwater they carry off are the lifeblood of the Chesapeake. At the same time, however, research over the past 30 years has diagnosed the problems that rivers bring to the estuary, especially overenrichment from the nutrients nitrogen and phosphorus, which cause excessive algae growth and a host of related problems.
It's important to remember that the problems are serious precisely because the rivers are so valuable in the first place. There's no other estuary in the world with a network of rivers like the one that feeds the Chesapeake. Nutrients cause problems only at excessive concentrations. They're the essential building blocks of the biological community and the rivers are where they come from.
The Chesapeake itself is a river, after all. It is the drowned valley of the Susquehanna. During the last ice age, or 20,000 years ago, sea level was about 100 meters (328 feet) lower than it is today, because much of the earth's water was tied up in the polar ice caps. One glacier extended, in fact, all the way down to what is tidal today, north-central Pennsylvania. The Susquehanna began at the edge of that glacier and ran southeast of the Atlantic, gathering tributaries as it flowed to its mouth on the edge of the continental shelf, well to the east to where the Virginia Capes are today.
As the earth began to warm up, sea level rose and the Atlantic's dense salty water flooded into the river's mouth, flowing in on the tides underneath the freshwater coming downstream. Eventually, the tidal water worked its way up the Susquehanna to Smith's Falls, just above Port Deposit, creating a 200-mile-long tidal river mouth which the Indians named Chesapeake.
The point here is that the Chesapeake has its origins in the Susquehanna and its tributaries. Thus every square inch in the drainage basins of those rivers is connected directly to the Bay. It is worth looking at their geography.
The Susquehanna is the largest river on the Atlantic Coast of the United States. It stretches all the way up through central Pennsylvania and into south-central New York, where it cradles the southern end of the Finger Lakes watershed. Those lakes flow north into Lake Ontario, but the land immediately to the east and south of them drains to the Chesapeake. Binghamton, Corning, and Elmira are all in the Susquehanna and so belong to the Chesapeake. In fact, until the river was dammed in the 1840s, spawning herring ran far enough up the Susquehanna from the Bay and the ocean that Binghamton had a commercial fishery in the spring. That distance is a full 500 miles (that's 200 miles of Bay and 300 miles of river above the Atlantic.
The Susquehanna's average discharge of fresh water is about 35,000 cubic feet per second, larger than the Connecticut at 16,500 cubic feet per second and the Hudson, 14,500 cubic feet per second combined. In fact, the Susquehanna contributes half the fresh water that enters the Chesapeake.
That statistic looks grossly inaccurate if one examines a map of the Bay. The Susquehanna's mouth between Havre de Grace and Perryville is only a half mile across, much smaller than the mouths of the Potomac (over five miles), the James (nearly four miles), and a dozen others. Even the relatively small Chester River has a mouth wider than the Susquehanna's. But look at the map again. The Potomac's mouth is the mouth of its hundred-mile-long tidal section. The Susquehanna's mouth, as maps define it, is just below the point where it becomes tidal.
In fact, the tidal section of the Susquehanna has a different name. It's called Chesapeake Bay. Now look at the map again and compare the upper Bay with the lower Potomac. That comparison will give you a sense of how big the Susquehanna really is.
Mind, though, that the Potomac is no small river either. It is, in fact, the eighth-largest river on the Atlantic Coast with an average of 11,200 cubic feet per second. Its branches come down all the way from West Virginia, the Shenandoah Valley of Virginia, western Maryland, and even south-central Pennsylvania. The James is also a major coastal river, with about 7,000 cubic feet per second coming out. It rises in Highland County, Virginia, out of the eastern slopes of the Appalachian mountains. Together, these three rivers contribute just over 75 percent of the Bay's fresh water.
The next three rivers, the Rappahannock, the York, and the Patuxent, are grouped together but are much smaller, at 1,500 to 3,000 cubic feet per second, remember, on average. But all three, and even the smaller ones, too, are important to the system. Ask anyone who lives on the Choptank or the Pocomoke or the Piankatank, the Sassafras, the Severn, or any of the others how valuable their rivers are. Ask any Bay scientist. Yes, the Chesapeake is rich in rivers, a happy fact for all of us who live by it.
For more happenings around the Bay in March see our other Chesapeake Almanac podcasts and read our blog posts "Tiny, Timid, Timberdoodle Dancers," March's Lion Has Lost His Teeth," and "Watching Northern Water Snakes in March."
