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Wetlands are combinations of land and water. They may be covered by water most of the time or only on occasion. Plants and animals living here must be specially adapted to survive the twice daily changes of incoming and outgoing tides, resulting mainly from the gravitational pull of the moon on the water as the earth turns. Virginia's tidal wetlands include salt marshes, brackish and freshwater marshes, and swamps.
Wetlands along the water's edge provide the following valuable services:
- Absorb excess flood water
- Protect uplands from the storm damage of wind and waves
- Provide constant, ideal habitat-including food and shelter for many animals and essential nursery habitat for others
- Filter out pollution
- Mix oxygen into the water.
Tributaries & Watershed
When it rains in the Chesapeake's drainage basin, or watershed, most of that water flows across the land surface into streams and rivers, then into the Bay and, eventually, on to the Atlantic Ocean. More than half of Virginia's land base rests in the Chesapeake Bay watershed, as do portions of New York, Pennsylvania, West Virginia, Delaware, Maryland, and the District of Columbia. The whole watershed, in fact, drains 64,000 square miles!
A tributary is a stream or river that contributes its water to another stream, river, or body of water. Everyone in Virginia lives fairly close to one. The main tributaries of the Chesapeake Bay flowing through Virginia are the James, York, Rappahannock, and Potomac rivers.
The names of the rivers in the basin reflect the early settlement of the Commonwealth. The Potomac, Rappahannock, Pamunkey, Mattaponi, and Chickahominy are tributaries with names originating from Algonquin, a Native American language spoken by the many tribes of the Powhatan Confederacy who first settled in the region. The Susquehanna River carries the largest amount of fresh water into the Bay; again, its name comes from Native American origins. Two other rivers, the James and the York, have English names given by European settlers. "Chesapeake" is yet another example of Native American influence, said to have meant "great shellfish bay."
The Chesapeake Bay is an estuary, a partly enclosed water body where fresh water from rivers meets ocean salt water, and the two mix. It is the largest estuary in our nation. Chesapeake Bay water is saltiest near the Bay's mouth and gradually becomes fresher to the north. This variation supports a wide array of plants and, as a result, the Bay is an essential nesting and nursery site for migratory waterfowl, small aquatic creatures, and fish.
This vast living resource base provides many recreational and commercial benefits to the Commonwealth. Virginia's commercial fisheries industry primarily includes finfish-menhaden, striped bass, croaker, and flounder; and shellfish-oysters, clams, scallops, and blue crabs from the Bay and ocean. The economic value of this annual commercial harvest is about $500 million. But the mix of the catch is changing. Several valuable commercial species of the Bay have declined over the years. Causes are attributed to pollution, disease, over-fishing, loss of habitat, or a combination of these factors.
For example, in the 1970s roughly 6 million pounds of oysters were harvested each year in Virginia. By 1997 the oyster harvest had dropped to a mere 300,000 pounds. The population of oysters in the Bay is now estimated to be only one percent of what it was prior to the Civil War. In 1998, the National Oceanic and Atmospheric Administration's stock assessment committee considered the blue crab stock "fully exploited" but not overfished. In its report, the committee found that the number of crabs three inches and greater in size has decreased since 1995. Other studies show that the average size of female crabs is also decreasing. Scientists attribute the declines to environmental conditions and increased fishing pressure.
The striped bass is an example of a resource whose fishery nearly collapsed but has recovered. Their numbers declined rapidly in the late 1970s through the 1980s, most likely because of over-harvesting and subsequent reproductive failure. Now, after several years of cooperative coastwide controls on striped bass fishing, their populations are rebounding.
The Atlantic Ocean and Barrier Islands
Virginia is fortunate to front the Atlantic Ocean. From Virginia Beach and the Eastern Shore, people can thrill at the sight of shorebirds, migratory birds, dolphins, or whales breaching. A wide assortment of marine mammal species swim off Virginia's shores. These include the Atlantic bottlenose dolphin, striped dolphin, harbor porpoise, humpback whale, and harbor seal, to name a few. Occasionally, Risso's dolphin and manatee will travel this far north as well. Five types of sea turtles join them: Kemp's ridley, Atlantic hawksbill, loggerhead, Atlantic green, and leatherback. Marine mammals, sea turtles, and pelagic (ocean) fish, then, are some of the important animals depending upon a clean ocean filled with species of plants and animals lower in their food chain to survive.
Once across the Bay and on the Eastern Shore, Virginians set foot on one of the most unique coastal ecosystems in the world. The southern part of the Delmarva Peninsula (named for Delaware, Maryland, and Virginia, the three states that make it up) is dotted on the seaside by a unique chain of barrier islands and lagoons. This pristine island ecosystem provides critical habitat for a wide variety of songbirds, shorebirds, waterfowl, finfish, and shellfish.
Along Virginia's Atlantic coast and crossing the 17.6-mile Chesapeake Bay Bridge-Tunnel, fishing boats, container cargo ships, barges, and oil tankers are evidence of the commercial importance of our ports. The Hampton Roads complex, including Portsmouth, Norfolk, Hampton, and Newport News, is one of the nation's major North Atlantic ports for commerce, ship-building, and military presence.
Sources of Pollution Threatening Coastal Waters
Pollution from an identifiable point, or "point source," comes from pipes, ditches, sewers, channels, tunnels, sewage treatment plants, factories, and containers of various types. While much of this pollution is treated, the wastewater still contains contaminants.
Non-point source pollution, by contrast, is difficult to identify since it is a mix of many things draining off the land. Muddy water flowing off of recently plowed farm fields or eroding construction sites blocks sunlight from reaching submerged plants that provide essential habitat for many young animals. It also is full of nutrients that lead to algae blooms, that later sink and die. During decomposition, oxygen is used and less remains available for other marine life. Sediment smothers fish eggs and clogs and tears the gills of young fishes. It settles on top of oysters and other bivalve mollusks, often killing them in the process.
Especially harmful to coastal wildlife is motor oil that leaks from cars and boats and, eventually, reaches the Bay and ocean. Oil improperly discarded from one car engine during an oil change (about one gallon) can produce an oil slick the size of six football fields! Motor oil is poisonous and likely to kill animals who ingest it. And oil that sticks to the feathers of ducks and birds prohibits them from flying.
Other toxics, or poisonous substances, may contaminate coastal waters, sediments, and body tissues in animals, especially near urban, industrial areas. These substances range from organic compounds produced during industrial processes to common household products, such as paint, battery acid, nail polish remover, and pesticides.
Since the 1972 ban on the pesticide, DDT, there is good news about bald eagles and pelicans. In the 1970s there were so few of these birds they were in danger of disappearing. The pesticide had run off land where it was used to control insects. It had gotten into rivers, bays, and the ocean, then into fish that bald eagles, pelicans, and other birds eat. Consequently, shells of eggs laid by these birds were not thick enough and broke before the young could completely develop and hatch. In 1970 there were about 50 bald eagle nests, but success in producing fledgling eaglets was very limited. By 1990 the number of "successful" nests in the Chesapeake Bay area had risen to 225.
- Has a drainage basin covering 64,000 square miles, extending into six states
- Is the largest estuary in the contiguous United States and one of the most productive in the world
- Has a main stem more than 195 miles long, which ranges from 3.4 miles near Aberdeen, Maryland, to 35 miles near the mouth of the Potomac River
- Receives 90 percent of its fresh water from five major tributaries: the Susquehanna, Potomac, James, Rappahannock, and York rivers, with the balance supplied by 150 smaller rivers and creeks
- Has 7,000 miles of shoreline and a surface area of more than 2,200 square miles
- Has a volume of some 18 trillion gallons of water and an average depth of less than 30 feet
- Is the home for 267 fish species and 2,700 plant and animal species, and is a major stop along the Atlantic Migratory Bird Flyway for songbirds and birds of prey
- Is a commercial and recreational resource for more than 13 million people living in its basin
- Receives 1.5 billion gallons of treated sewage effluent per day and waste from 3,000 point source dischargers in its upper drainage basin
- Hosts a commercial fishing industry that generates $269.4 million in annual income to the state
and about Virginia's Coast:
- Home to the Southern Watershed, located in southeastern Virginia and making up the southern portions of the cities of Chesapeake and Virginia Beach, which is one of the most biologically diverse regions of the state and supports more than 40 rare plant species and 10 terrestrial, estuarine, and palustrine wetland communities
- Also home to Back Bay National Wildlife Refuge and False Cape State Park, in the Southern Watershed, which attract tens of thousands of visitors each year
- Site of Northampton County, the southernmost county on the Eastern Shore, which has been designated a World Biosphere Reserve by the United Nationas due to the rich habitat it provides for over 260 species of birds and countless other fish and wildlife.
Underwater grass restoration is very important, but is still considered relatively experimental. The Virginia Institute of Marine Science has been transplanting submerged aquatic vegetation, or SAV, into the Chesapeake and Magothy bays since 1978. Transplanting techniques have been perfected, but light is essential to SAV growth. Success depends on our ability to reduce hindrances like sediments and nutrients which can cloud these waters.
Coastal waters used to be filtered and cleaned courtesy of a thriving oyster population, and for years people across the country enjoyed eating oysters harvested from the Bay. Oyster reefs used to protrude above coastal waters and were so prevalent they were considered navigational hazards! Oyster reefs have always been home to many valuable sport fish and other aquatic animals such as blue crabs, grass shrimp, mussels, sponges, and barnacles. Because of their important ecological contribution, oysters are now being transplanted onto sanctuary reefs in the Great Wicomico and Piankatank rivers, and in Pungoteague Creek on Virginia's Eastern Shore, under a program launched by the Virginia Marine Resources Commission. Recently, the Virginia Coastal Program [unmapped link]
at DEQ and the Chesapeake Bay Foundation
have joined in this effort. Many citizens are growing "oyster gardens" alongside their docks to supply more oysters to transplant, and students are helping to establish reefs in the Elizabeth River through school-sponsored programs. (See Water Resources
chapter for volunteer opportunities.)
All of these projects offer hope for the future of the Bay and its marine life. As people become more aware of the direct links between actions at home and impacts on the waters of the Bay and ocean, we have a better chance of preserving the many treasures found along Virginia's shores.
- Blankenship, Karl (editor). Bay Journal, Seven Valleys, PA: Alliance for the Chesapeake Bay.
- Horton, Tom and W. E. Eichbaum. 1991. Turning the Tide - Saving the Chesapeake Bay. Annapolis, MD: Chesapeake Bay Foundation, 328 pp.
- Reshetiloff, Kathryn (editor). September, 1997. Chesapeake Bay Introduction to an Ecosystem. EPA 903-R-97-024 & CBP/TRS 184/97, 30 pp.
- Barnes, Brooks Miles and Barry R. Truitt (editors). 1997. Seashore Chronicles - Three Centuries of the Virginia Barrier Islands. Charlottesville: University Press of Virginia.
- WOW!: The Wonders of Wetlands (latest ed.)
- Project WET, Curriculum & Activity Guide, 1995.
- The Coastal Connection: Migratory Birds of Virginia, A Curriculum Supplement for Virginia Educators, 1999. Richmond, VA - Virginia Department of Environmental Quality
Fundamental Learnings Related to Bay & Coastal Resources
- Virginia's coastal resources are extremely valuable to the state's economy and environment.
- Coastal resources include wetlands, rivers, dunes, the Chesapeake Bay, the Atlantic Ocean, the Barrier Islands, Back Bay Dismal Swamp, and all of their natural components such as soil, water, plants, and animals.
- All Virginians live in a watershed and can have a major impact on water quality in the Chesapeake Bay and upon all of our coastal resources, the Atlantic Ocean, and the Gulf of Mexico.
- The sun provides light and warmth to land, air, and water. When muddy water blocks light to green plants, such as eelgrass, they die.
- Blue crabs and fish need the protection and oxygen that underwater plants in their habitat provide.
- Oyster reefs are important to ocean ecology by providing habitat (shelter, food) and filtering capacity.