Science as Inquiry

  • Ability to do scientific inquiry (5-8, 9-12)
  • Understanding of scientific inquiry (5-8, 9-12)

    Life Science

  • Populations and ecosystems (5-8)
  • The interdependence of organisms (9-12)

    Earth and Space Science

  • Structure of the earth system (5-8)

    Science in Personal and Social Perspectives

  • Populations, resources, and environments (5-8)
  • Natural resources (9-12)
  • Environmental quality (9-12)
  • Natural and human-induced hazards (9-12)
  • Science and technology in local, national, and global challenges

  • What's In Your Watershed?
    Image courtesy of the NOAA Photo Library

    When we are age 4 or 5, our parents and teachers begin teaching us our telephone number and address. The importance of knowing these is obvious—to help ensure our safe return when we are lost. But do you know your watershed address? Everybody has one, and it's an important address to know, because we each impact our watershed. Not only do you consume the water in your watershed, but your activities, such as clearing vegetation or fertilizing your lawn, can impact water flow and pollution.

    What Is A Watershed?

    A watershed is an area of land where all the water including rain, snowmelt and groundwater flows into the same stream, lake, river or bay. The boundary of a watershed is not tied to any political boundaries, but to the topography of the land. A ridgeline, or high area, separates one watershed from another. Water flows from the ridgeline down, often to an elevated plain or plateau. A steep slone, called a fall line, often connects the plateau to the low plains. At the water's edge is the riparian buffer, a crucial area because it is the last section of land before the water begins. See a sample cross-section of a watershed.

    The vegetation of the riparian buffer acts as a filter, bank stabilizer, and habitat. As runoff carries sediments, nutrients and debris toward the water, the plants in the buffer zone trap this material and slow down the runoff flow. The roots of the plants help to stabilize the sediment, reducing erosion and streambed scouring. The flora of the riparian buffer not only supplies habitat for the terrestrial animals near the water, but also improves the aquatic habitat. Shade from vegetation helps keep the water cool and oxygenated, providing habitat for fish, crabs and other aquatic animals. The wider the buffer, the better for the environment. It has been estimated that a minimum of 50 feet is necessary for bank stabilization, 100 feet for filtration of runoff and improvement of aquatic habitat conditions, and 300 feet for terrestrial habitats.

    U.S. Watersheds

    The largest watershed in the United States is the Mississippi River Basin watershed. This watershed covers 1,200,000 square miles (about 40% of U.S. land), and is home to approximately 70,000,000 people (about 25% of the U.S. population). Second in size to the Mississippi River Basin, is the Chesapeake Bay watershed. This watershed, which drains into the United States' largest estuary, is comprised of only 64,000 square miles (about 2% of U.S. land) but more than 15,500,000 people (about 5.5% of the U.S. population). This makes the Chesapeake Bay watershed population more than 4 times as dense as that of the Mississippi River Basin, a fact that could greatly impact water quality.

    The Chesapeake Bay watershed is composed of five major geographic areas: Appalachian plateau, ridge and valley, Blue Ridge, piedmont, and coastal plain. It covers parts of New York, Pennsylvania, Delaware, Maryland, Virginia, West Virginia and the District of Columbia. The most densely populated portion of the watershed is the coastal plain region which falls almost entirely within Maryland and Virginia. Water quality issues have plagued the Chesapeake Bay for decades. During the mid- to late-1980s, in an effort to help protect the Chesapeake Bay, both Maryland and Virginia passed laws requiring that any future land development include a 100 foot vegetated buffer between any land use and the water. To better understand the effects of human activity on the Chesapeake Bay watershed, this data activity will look at land cover patterns and evaluate the results of buffer laws on riparian buffers for several areas in the watershed.

    Data Activity

    In this data activity, students will use the Chesapeake Bay Program's Watershed Profile Data and land use data from the Middle Peninsula Planning District Commission's Dragon Run Special Area Management Plan to compare land use and riparian buffers surrounding some of the tributaries of the Chesapeake Bay and to examine a unique environment in the watershed.

    The Chesapeake Bay Watershed is home to several major cities including Washington D.C., Baltimore, Richmond and Norfolk. In this activity we will look at the land use along the rivers that support these cities to see how well these areas are protecting the water with vegetated buffers.

    Divide your class in five groups. Each group will examine a different subwatershed:

    For the first four groups the data can be accessed at CBP Watershed Profiles. Scroll to the bottom, and from the drop down list select the appropriate subwatershed. The James River groups will have a second tier of subwatersheds to select from. Print this page with the land cover and forest fragmentation pie charts. Then under the Landscape Tab at the top of the page, select Forests. Print this page.

    The Dragon Run Swamp data can be accessed in an Excel spreadsheet from the Middle Peninsula Planning District Commission's Dragon Run Special Area Management Plan. There are 438 pieces of land that are categorized by land use type with the acreage listed. Have the students sum the acreage for all the various land types (combine the 3 forest types into one category) and fill in the yellow chart on the right. Have the students calculate for each land type its percentage of the total acreage. Create a pie chart of the percentage of land type for the Dragon Run Swamp.

    The Dragon Run Swamp is a pristine 140 square mile watershed located in the coastal plain of Virginia that has remained largely undeveloped. The Smithsonian Institute has ranked the Dragon Run second in ecological significance out of 232 areas in the Chesapeake Bay. A Special Area Management Plan or SAMP has been established to help maintain the cultural, historic and natural character of this area.

    Discussion Questions

    Special thanks to Dave Fuss and Lewis Lawrence at the Middle Peninsula Planning District Commission for providing Dragon Run information and data for this Data Tip.

    If you have questions about the Data Tip of the Month or have suggestions for a future data tip, contact Lisa Lawrence, Bridge Webkeeper.

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