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Turning the Tide: Saving the Chesapeake Bay

Turning the Tide: Saving the Chesapeake Bay

by Tom Horton, William Eichbaum, Chesapeake Bay Foundation

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Horton (an environmental columnist for The Baltimore Sun) updates his 1991 work describing the ecosystem of the Chesapeake Bay, into which waters from the states of Virginia, Maryland, Pennsylvania, and New York flow, and assessing the state of its environment and efforts to clean it up. He argues that progress on pollution has been uneven and makes


Horton (an environmental columnist for The Baltimore Sun) updates his 1991 work describing the ecosystem of the Chesapeake Bay, into which waters from the states of Virginia, Maryland, Pennsylvania, and New York flow, and assessing the state of its environment and efforts to clean it up. He argues that progress on pollution has been uneven and makes recommendations for programs and policies to be implemented by the federal government and the involved states. Annotation ©2004 Book News, Inc., Portland, OR

Editorial Reviews

President, Worldwatch Institute - Lester R. Brown

"Turning the Tide is an exciting book, rich in information and insights on the Chesapeake Bay ecosystem. One of the world's richest estuaries, the Chesapeake is a 'protein factory.' When healthy, it produces almost as much protein as the Mediterranean Sea. The purpose of this book, and the Chesapeake Bay Foundation which sponsored it, is to build support for restoring the bay's health."
President and Chairman, National Geographic Society - Gilbert M. Grosvenor

"Turning the Tide is a fascinating checkup of the health of our beloved Chesapeake Bay. It gives us reason for hope—and for moving with dispatch to tackle the many ills that still plague this wondrous waterway."
author of Beautiful Swimmers: Watermen, Crabs, and the Chesapeake Bay - William W. Warner

"Make no mistake about it, the clock is running out on the Chesapeake. In Turning the Tide, Tom Horton and William Eichbaum tell us in the clearest possible terms what is happening to the bay and what is to be done about it. More than a status report, what we have here is a thoughtful and well-documented call to action."

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Turning the Tide

Saving The Chesapeake Bay

By Tom Horton, William Eichbaum


Copyright © 2003 Chesapeake Bay Foundation
All rights reserved.
ISBN: 978-1-55963-549-3


The Bay Connects Us, the Bay Reflects Us

The Small, Skinny Bay

The Chesapeake Bay is on our maps and in our minds as a large and dominant body of water, fringed on either side by tidewater Maryland and Virginia, ending at Norfolk to the south and at Havre de Grace to the north. Although the bay is commonly described as 195 miles long and from 4 miles to 30 miles wide, it is a system about twenty times that size. Nearly fifty significant rivers and thousands of streams, creeks, and ditches penetrate deep into the surrounding land. They extend the bay northward to Cooperstown, New York, site of the Baseball Hall of Fame; as far west as Pendleton County, West Virginia; southward in Virginia to Lynchburg and Virginia Beach; and eastward to Seaford, Delaware, and Scranton, Pennsylvania.

All of the land thus encompassed, sprawling 64,000 square miles between upstate New York and southeastern Virginia, slopes toward the Chesapeake Bay. Every drop of rain that runs off these lands flows toward the bay. So does the discharge from every sewage pipe, every industrial outfall and uncontained oil spill, every Styrofoam coffee cup casually tossed into a ditch. When soil erodes from farmland, or from a forest bulldozed for development, the sediment can head only in one direction—bayward. This is the drainage basin, or watershed, of the Chesapeake Bay; and on such a map the bay appears neither dominant nor long and broad—just a smallish pool of water on the receiving end of all our activities, wise and foolish, across the vast lands of the watershed.

Even placing the bay in the context of its watershed may understate the degree to which the land can influence its waters. This is because the bay's considerable length and breadth conceal how skinny it is. There is little water in it—the Chesapeake is very, very shallow. About 1,000,000 feet long from head to mouth, and up to 100,000 feet wide, it averages only 21 feet in depth. Acre for acre across the lands of its watershed, the bay has less than one-tenth the volume of water of most of the world's other coastal bays to absorb and dilute whatever pollutants wash from farms and cities around it. (See Figure 1.1.)

The Great, Green Filter

To understand how watersheds and their waters interact, start by visiting and comparing two kinds of small streams anywhere in the Chesapeake basin—one in a mostly forested area, the other in an urban-suburban setting. Notice how when it rains in the wooded stream valley, the leaves and branches of the forest intercept and deflect the raindrops, softening the impact of those that reach the ground. The rain that falls is literally sponged up by the dense vegetation and the deep leaf duff of the forest floor. Only in very intense storms will the stream's channel receive enough runoff to go rampaging destructively down its course, cutting at its banks and scouring its bed.

By contrast, the paved areas, house roofs, and compacted soils of the urban-suburban stream's more developed watershed will channel as much as 100 times the amount of water from the same rainfall into the stream course; and the runoff will occur several times more quickly, without the rough, spongy surfaces of the forest to slow its passage. Conversely, in dry periods, the forested stream will continue to be fed by seepage through its banks and bottom from all the rain that soaked into the ground. On the developed stream, too much left the watershed too fast and not enough soaked in. The same channel that raged with rainfall will lie nearly empty the rest of the time.

The upshot is that the forested stream has lower peak flows than the developed stream when it rains and higher "base" flows when the weather is dry. The forested stream is more stable. The natural vegetation, which can also include wetlands and meadows, performs other services—such as filtration of pollution from runoff—that maintain a diverse and healthy population of everything from aquatic insects to trout and bass.

This scenario can be extended to the bay. In pre-European times, the Chesapeake's watershed was mostly forest, and estimated peak flows of freshwater into the bay during storms were 25 to 30 percent lower than today. Base flows during droughts were probably 10 to 15 percent higher. Thus, we see that natural landscapes, in relation to the bay, are more than homes for wildlife, sources of wood, filters for pollution, and pleasant settings for outdoor recreation. They also wring order from chaos, impart to the whole system a resilience, a capacity to moderate impacts of both storm and drought. In modern times, development and agriculture have removed some 40 percent of the watershed's original landscape. And much of that loss has been on the lands closest to the bay and its tidal rivers, precisely where it has the greatest impact on water quality.

This book will show how other parts of the Chesapeake system—the shellfish and sea grass communities of the bay's bottom, for example—also buffer the bay against both natural and human disruption. And it will explain how, as we continue to change the original nature of the system's resilience, we risk destabilizing it beyond recovery.

The Amputated Bay

The tributaries, or rivers and streams, of the watershed are much more to the bay than a collector system sending pollution downstream. They are highways and habitat for spawning fish, a vital link in the bay's fabled seafood production. For thousands of years, great schools of herring and shad glutted the bay each spring, extending like living fingers of the ocean to the farthest upstream limits of the drainage basin. Starting far out at sea, these fish ran up Virginia's James River, past Jamestown and Hopewell. Racing through Richmond, pushing ever upward, they turned into the Rivanna, pressing on to Charlottesville and beyond. The shad sought the rivers, while the smaller herring continued up streams no wider than a person's stride. Even larger numbers of both species thronged Pennsylvania's Susquehanna, the bay's biggest river, embarking on the longest migration of any fish in eastern North America. They mounted the watershed as far as Binghamton, Elmira, and Cooperstown in New York State.

Fish that run up rivers from the sea to spawn are called anadromous. The bay has several such species, of which the shad and herring are perhaps the most ambitious voyagers. (See Figure 1.2.) Like the salmon of the West Coast, they appear to be drawn back to the waters where they were born by homing in on a sort of "organic bouquet," or scent that is unique for each river and stream in the vast drainage basin. In navigating from their ocean home, the fish may also be guided by the angle of the sun, the earth's magnetic field, currents, temperature, the amount of salt in the water, or a combination of all these. Exactly how they find their way home remains a mystery.

Come autumn, usually on nights when the moon is dark and a storm has just passed, an even more curious traffic stirs throughout the circulatory system that weaves together the bay and its basin. In the streams of lands as distant as the West Virginia mountains, the rolling farmland of Virginia's Shenandoah Valley, and the swampy river bottoms of Maryland's Eastern Shore, eels are stirring, undergoing physical changes to prepare them for the reverse of the shad's spawning trip. The eels will move downstream through the bay, homing in, along with eels from all over North America and Europe, on the Sargasso Sea, their universal spawning grounds.

Species that run down rivers to the sea to spawn are called catadromous, and eels are the bay's only full-fledged example of this behavior. Migrating eels may reach nearly 4 feet in length and weigh more than 6 pounds. The parent eels all die upon spawning, sinking into the depths of the Bermuda Triangle. Great, slow currents seize the helpless young, which at that stage of life resemble transparent willow leaves, and transport them across the ocean. Months, even years, later, as tiny eel-like forms, or elvers, they arrive near the mouths of Chesapeake Bay and other inlets of the Atlantic coast. There is not even the possibility of a "bouquet" imprinted at birth to explain how they wriggle their way from there to every capillary of a watershed they have never experienced. We only know that what draws them back is a powerful force that has been working for millions of years.

During the last century and a half these living connections, anadromous and catadromous, between the oceans and the bay watershed have weakened considerably. Early settlers in Pennsylvania rejoiced as the shad runs in early spring saved them from winter's near-starvation. Now, no living Pennsylvanian would remember those glad migrations. Overfishing during the spawning runs up the bay was intense. In the mid-nineteenth century, shad were taken by the ton in huge haul seine nets that would sometimes block an entire river.

But the death knell for the great spring runs sounded with erection of insurmountable dams on the James and the Susquehanna, beginning in the 1800s. In effect, these and thousands of smaller dams and stream blockages have cut off thousands of miles of historic spawning waters. The runs of shad, herring, and other species continue, in weakened measure, to this day on some rivers and streams. But it is well to remember, as we try to restore the former vitality of the bay, that its health is linked to the whole scope of the watershed. And with respect to fish migration, we are currently dealing with a partial amputee.

An Unruly Beast—The Estuary

Just as the bay branches upstream throughout a sixth of the Atlantic seaboard, downstream at its mouth it is open to the full scope of the ocean. The resulting collisions of sweet and salt—fresh river water flowing seaward and ocean water pushing inland—make what we call an estuary. The Latin verb aestuare —to heave, boil, surge, be in commotion— gives fair warning that this place is no mere river, running in only one direction for all time. Nor is it a lake, its waters turning over sedately once or twice a year as the surface layers cool and warm. Neither does it feature the predictable currents and constant, salty chemistry of the oceans. Estuaries are among the liveliest natural systems of the planet. They are the aquatic world's three-ring circuses of motion, productivity, and changeableness. There are about 850 such places in North America, from Long Island Sound to San Francisco Bay, but none among them so large and potentially bountiful as Chesapeake Bay.

I say "potentially" because the modern-day Chesapeake is a system in deep trouble, struggling for survival. In these pollution-conscious times, we are always asking, What is the quality of our waters? How are they doing? Do they and the life they hold seem to be coming back or going sour? If we were to observe and monitor the bay for a few days, or even a few years, to try to give it a grade, we might end up exasperated, wanting to flunk it solely for unruliness. That is the essential nature of estuaries—neither ocean nor river, but a transition zone, an edge where both systems overlap and struggle to assert themselves. That nature makes for a complicated and quirky system, one that is taxing both to creatures who would live in it and to those who would understand it, a system that needs all the stabilizing mechanisms (like its forested lands) it can get. But it is also a system capable of sustaining more life, more productivity for its size than virtually any other place on Earth. To see the method in the bay's apparent madness—to develop a frame of reference for asking, "How's the bay doing?"—it helps to begin when the only history was written by wind, river, and rock.

A Rare Flower—The Geologic Bay

The present Chesapeake Bay is just the latest in a long line of bays here. Indeed, there may well have been at least ten bays here during the last 5 million years. For most of the last half-million years, there has not even been an estuary at this point on the coast, just the narrow river valley carved by the mighty Susquehanna across the coastal plain and the continental shelf. A second channel was cut by the James, the two joining around Norfolk. The ancient riverbeds today form the bay's main shipping channels.

Intermittently throughout geologic time, the earth's climate has cooled so that large portions of today's oceans became bound up in the polar ice and glaciers. Sea level then was as much as 100 meters (325 feet) below where it is today, the surf breaking more than a hundred miles east of the current beaches. Only in the relatively short (measured in tens of thousands of years) interglacials, the warmest periods between ice ages, do the ice melt and the heave and surge of the rising seas gorge the coastal river valleys and inlets. During those brief, geologic summers, estuaries such as the Chesapeake swell and blossom like rare flowers within the nooks and crannies of the continental fringes, only to wither away with the onset of the next ice age and the reabsorption of the seas into the polar ice.

Today's Chesapeake began to fill about 10,000 years ago as the rising sea level reached the bay's present mouth and backed up the river flows from the Susquehanna and the James. The slope of the lower river channels was so slight that the flooding proceeded rapidly up their valleys. Around 9,000 years ago, the head of the newborn bay had almost reached Baltimore, though it was much narrower and shallower than today. Some 6,000 years ago, as Sumerians in Asia were inventing writing, the bay had widened and deepened, assuming something like its present form. By 3,000 years ago, as Rameses II ruled Egypt and Troy was sacked, the Chesapeake as we know it today had formed.

Perhaps there were a few seconds of geologic time then when the estuary could be said to have been in equilibrium, neither coming nor going; but ever since, its channels have been filling in with the sediments that continually wash from its shores and from the lands of the watershed. As it fills, its waters eventually will be squeezed upward and outward, to spread in a wide, shallow film across much of today's Eastern Shore. They will also inundate the western shore's low-lying peninsulas from Aberdeen, north of Baltimore, on down to the marshes of Guinea in Gloucester County, Virginia, at the mouth of the York River. This process will take a few thousand years unless human influences—dredging, for example, or the accelerating rise in sea level fueled by global warming—override expected climatic and geologic events. Ten thousand years from now, perhaps only a marsh will commemorate where the Chesapeake dwelled.

The great estuary will be gone. Or will it? Water will still flow from the watershed, will still seek its level in the sea, slowly carving new channels into the sediments left behind, setting the stage for the next coming. And even a quarter-million years hence, as the glaciers lie heaviest on the land and the seas have shrunk back off the continental shelves, who can say that November's eels and April's shad will not continue to come and go in a few, remnant tributaries of the coastline, safekeeping in their genes and instincts the annual rituals of once and future bays?

Slosh and Burp—The Wind's Will

The bay's geologic variability is mirrored on time scales as short as the everyday circulation of water. Tides send a charge of water rippling up and back down the 195-mile basin twice in every twenty-four-hour day. These tides, two highs and two lows every day, stretch as far up the bay's rivers as Washington on the Potomac and Richmond on the James. Many creatures of the estuary synchronize their lives to these periodic movements of water. The abundant periwinkles that scale the stalks of marsh grass to stay above the rising tide will continue their up-and-down migrations far from their native bay. (People who once took Chesapeake periwinkles to Alabama found them on the living room floor the next morning. As the tide rose back on the Chesapeake, the periwinkles had scaled the walls of their aquarium in Birmingham.) Likewise, crabs taken from Tangier Island, Virginia, and put into a tank in Pittsburgh, Pennsylvania, will shed their shells in accordance with the tidal clockwork back on Tangier.

Nothing would seem more regular and predictable than the tides, and that is true as far as when each high and each low occur. But how high and low they go is quite another matter. Because of the Chesapeake's long and shallow shape, movement of water in it is ruled to an unusual extent by the caprice of wind. A northwest blow may literally shove much of the bay's water out the mouth of the estuary and hold it there for days. High tides still come on schedule, but there is not much to them. On the other hand, the succeeding lows are memorable, exposing thousands of acres of normally submerged bottom—just one of the many stresses that life in the estuary must deal with. Conversely, a steady northeast wind may pile water up in sections of the bay several feet above normal, flooding low-lying shorelines with salty water, severely limiting the kinds of plants and animals that can survive there.

Certain winds may also have potentially harmful effects by triggering seiching, or sloshing motions, within the bay's deeper waters, tilting them from the eastern shore to the western shore, much like the motion you can set up by wiggling your hips in the bathtub. This in turn can cause the bay to "burp," or heave up, oxygen-poor waters from its deep channels into shallower areas—another in the long line of unpredictable and stressful phenomena encountered by life in estuaries. On the Chesapeake, local winds tinker as much as 90 percent of the time with the regular cosmic clockwork (like the moon's gravitational pull) that drives the tides. An extreme wind, such as a hurricane, may temporarily increase the volume of water in the bay by more than 30 percent. Winds routinely play the bay like a concertina, pumping and squeezing its normal water volume upward and downward by 10 to 20 percent.


Excerpted from Turning the Tide by Tom Horton, William Eichbaum. Copyright © 2003 Chesapeake Bay Foundation. Excerpted by permission of ISLAND PRESS.
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
Excerpts are provided by Dial-A-Book Inc. solely for the personal use of visitors to this web site.

Meet the Author

Tom Horton is an environmental columnist for The Baltimore Sun, and author of Bay Country (Johns Hopkins, 1994), Island Out of Time (Norton, 1996) and Water’s Way (Johns Hopkins, 2000).
The Chesapeake Bay Foundation, founded in 1967, is the largest nonprofit conservation organization working solely to save the Chesapeake Bay. Based in Annapolis, Maryland, the Foundation is supported by more than 100,000 active members.

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