Chesapeake Bay Program - A Watershed Partnership

Bay Pressures

The Chesapeake Bay and its many tributaries endure an array of assaults from the air, water and land. The watershed's worst problem is nutrient pollution, which fuels the growth of algae blooms that impact water quality and aquatic life. Chemical contaminants, air pollution, landscape changes, erosion and over-harvesting of fish and shellfish also stress the Bay and its wildlife.

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Land & People

Everything we do on the land—from driving our cars to spreading fertilizers on farms and suburban lawns—has an impact on the Bay and our local waterways.
Population Growth | Development | Impervious Surfaces | Stormwater | Land Use | Transportation

Air & Water Pollution

Nutrients, sediment and chemical contaminants that make their way to the Bay worsen water quality and stress aquatic life. Airborne nitrogen that falls onto the land can also add to pollution loads to local waterways.
Nutrients | Sediments | Chemical Contaminants | Air Pollution

Fisheries Harvest

The Bay and its tributaries provide rich grounds for commercial and recreational catches. Overfishing, pollution and disease now threaten many fish and shellfish.
Blue Crab Harvest | Oyster Harvest | American Shad Harvest | Atlantic Menhaden Harvest | Striped Bass Harvest

Natural Factors

There are many natural, uncontrollable pressures on the Bay. High temperatures, strong storms and inconsistent freshwater flows from rivers can all impact water quality and aquatic life.
Weather | River Flow | Groundwater

Invasive Species

Learn what invasive species are and why they have a negative effect on the Chesapeake Bay ecosystem, plus get links to more information on six invasive species: mute swans, nutria, phragmites, purple loosestrife, water chestnut and zebra mussels.
Mute Swan | Nutria | Phragmites | Purple Loosestrife | Water Chestnut | Zebra Mussel

Climate Change

Like countless other parts of the world, the Chesapeake has begun to feel some of the effects of a changing climate, such as sea level rise and increased temperatures. Other possible impacts may include lower dissolved oxygen levels, more precipitation, and changes in some species’ abundance and migration patterns.

Bay Pressures Assessment:

Pressures on the Bay ecosystem, as assessed in March 2009:

• Natural Factors: Annual rain and snowfall influence the amount of water that flows in rivers. Pollution entering the Bay each year generally corresponds with the volume of water that flows from its tributaries and the concentration of pollutants in that water.
• Pollutants: The Chesapeake Bay and its rivers are unhealthy primarily because of pollution from excess nitrogen, phosphorus and sediment. The main sources of these pollutants are agriculture, urban and suburban runoff, wastewater, and air pollution.
• Land Use: The Bay’s decline is directly linked to the rise in population and corresponding development in the watershed.
• Other Pressures: Climate change, invasive species and fisheries harvest are additional factors that impact the health of the Bay ecosystem.

To learn more about Bay pressures, visit our factors impacting Bay health assessment section.