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Learn the Issues

There are many problems facing the Chesapeake Bay. The major pollutant to the Bay is excess nutrients, which come from agriculture, urban/suburban runoff, vehicle emissions and many other sources. Excess nutrients fuel the growth of algae blooms, which block sunlight that underwater bay grasses need to grow. When algae die, they are decomposed in a process that depletes the water of oxygen, which all aquatic animals need to survive. Learn more about some of the issues facing the Chesapeake Bay:


Livestock manure and poultry litter account for about half of the nutrients entering the Chesapeake Bay. States across the watershed have committed to reducing this nutrient load by working with farmers to properly apply manure to cropland, develop animal waste storage systems and restrict animals from streams.

More than one-quarter of land in the Chesapeake Bay watershed is devoted to agricultural production. Agriculture is essential to all people: farms provide us with food and fiber, natural areas, and aesthetic and environmental benefits. But agriculture is also the single largest source of nutrient and sediment pollution entering the Bay. While conventional tillage, fertilizers and pesticides can be beneficial to crops, their excessive use can pollute rivers and streams, pushing nutrients and sediment into waterways.

Air Pollution

Mobile sources of air pollution—like cars, trucks and off-road vehicles; boats; airplanes; gas-powered lawn tools; and farm and construction equipment—can produce pollutants that can harm our air, land and water. (M.V. Jantzen/Flickr)

Air pollution doesn’t just cloud the air we breathe. It can also harm our land and water. What goes up must come down, and pollution released into the air—by cars, trucks, gas-powered lawn tools, power plants and other sources—will fall back to the earth’s surface, where it could wind up in our waterways. Nitrogen and chemical contaminants are two pollutants that harm both air and water. But maintaining the forests that absorb airborne pollutants and enacting regulations to reduce emissions from our vehicles and power plants are two ways that we can reduce air pollution across the watershed.

Bay Grasses

A volunteer helps the U.S. Fish and Wildlife Service track underwater grass abundance in the Chesapeake Bay.

Underwater grasses—also known as submerged aquatic vegetation or SAV—are plants that grow in the shallow waters of the Chesapeake Bay and its streams, creeks and rivers. Underwater grasses are a critical part of the Bay ecosystem: they provide wildlife with food and habitat, add oxygen to the water, absorb nutrient pollution, trap sediment and reduce erosion. Like all plants, underwater grasses need sunlight to grow, which makes improving water clarity an important step in underwater grass restoration.

Blue Crabs

More than one-third of the nation's blue crab catch comes from the Chesapeake Bay. (Tuaussi/Flickr)

There is nothing more “Chesapeake” than the blue crab. The Bay’s signature crustacean is one of the most recognizable critters in the watershed, and supports commercial and recreational fisheries. But blue crabs are vulnerable to pollution, habitat loss and harvest pressure, and their abundance has fluctuated over time. Water quality improvements, underwater grass restoration and proper harvest management will help maintain this valuable resource into the future.

Chemical Contaminants

From the insecticides that are put on farm fields to the cleaners we use to disinfect our homes, chemical contaminants can enter the Chesapeake Bay in several different ways, affecting the survival, growth and reproduction of fish and wildlife.

Almost three-quarters of the Chesapeake Bay’s tidal waters are considered impaired by chemical contaminants. These contaminants include pesticides, pharmaceuticals, metals and more, and can harm the health of both humans and wildlife. From the insecticides that are put on farm fields to the cleaners we use to disinfect our homes, contaminants can enter the Bay and its tributaries in several different ways. While production bans have lowered the presence of some contaminants in the watershed, others are still widely used today.

Climate Change

As sea levels rise and weather events become more extreme, coastal flooding and erosion will increase across the Chesapeake Bay.

A changing climate will affect the Chesapeake Bay. Some effects—like rising seas, warming water temperatures and prolonged periods of extreme weather—have already been observed in the region. Other impacts include a rise in coastal flooding and shoreline erosion and changes in wildlife abundance and migration patterns. Chesapeake Bay Program partners are working to increase the climate resilience of resources and communities across the watershed.

Conowingo Dam

The Conowingo Dam is located on the lower Susquehanna River. While the reservoir behind the dam has long captured sediment flowing downstream, recent studies have drawn attention to the reservoir’s changing effectiveness as a “pollution gate.”

The Conowingo Hydroelectric Generating Station, or Conowingo Dam, is one of three dams on the lower Susquehanna River. While the reservoir behind the dam has long captured sediment flowing downstream, recent studies have drawn attention to its changing effectiveness as a “pollution gate.” Because the reservoir behind the dam is essentially full, it is only trapping sediment in the short term. During large storms and severe floods, sediment and attached nutrients can “scour” into the Susquehanna, moving over the dam and into the Chesapeake Bay. While it is possible to manage sediment behind the dam, researchers have found that reducing upstream nutrient and sediment pollution would be more beneficial to the Bay.


Development can have a lasting impact on the natural environment, threatening the conservation of forests and farms and creating new pathways that send pollutants into rivers and streams.

As more people move into the Chesapeake Bay watershed, more land is cleared for the development of roads, homes and businesses. Residents have expanded out of traditional urban centers and into bigger houses on larger lots, turning forests, farms and other valuable landscapes into subdivisions, shopping centers and parking lots, and impacting the health of our rivers and streams.


Education and engagement opportunities help educate the public about the importance of Chesapeake Bay restoration.

One of the most important parts of Chesapeake Bay restoration is teaching the public about the Bay and its local waterways. Bay Program partners work to educate and engage residents through formal curriculum-based learned and informal programs at parks and other sites.

Fish Consumption Advisories

Fish consumption advisories are not meant to discourage people from eating fish and shellfish. Instead, they are meant to minimize public exposure to chemical contaminants. (Ben Fertig/IAN Image Library)

Fish consumption advisories are public health notices that warn people about the possible health risks associated with eating fish or shellfish from a certain waterway. States and local governments issue fish consumption advisories for rivers and streams when there is concern that locally caught fish could contain chemical contaminants.

Forest Buffers

Forest buffers provide enormous benefits to the Chesapeake Bay and its tributaries. Forest buffers prevent pollution from entering waterways, stabilize stream banks, provide food and habitat to wildlife and keep streams cool during hot weather.

Forest buffers, or the trees, shrubs and other plants that grow next to streams and rivers, are critical to the health of the Chesapeake Bay. Forest buffers prevent pollution from entering waterways, stabilize stream banks, provide food and habitat to wildlife and keep streams cool during hot weather. Chesapeake Bay Program partners are working to restore 900 miles of forest buffers per year until 70 percent of all stream banks and shorelines in the watershed are buffered.


Roads, homes and other human activities have altered the composition of forests across the Chesapeake Bay watershed, reducing tree cover and fragmenting those forests that still exist. Fragmented forests are less resilient to disturbances and more prone to negative influences like wildfires and invasive species.

Forests are critical to the health of the Chesapeake Bay. Large stands of trees can protect clean water and air, provide habitat to wildlife and support the region’s economy. But human activities have altered the watershed’s forests, reducing tree cover and fragmenting forests that still exist. Conserving and expanding forest cover is a critical, cost-effective way to reduce pollution and restore the Bay.


Pollution from farms, cities and suburbs can seep into underground aquifers, contaminating groundwater that will eventually reach the Chesapeake Bay. (Scott Phillips/U.S. Geological Survey)

Drops of rain or snow that fall onto the land do not always wash straight into rivers or streams. Instead, precipitation can seep through the soil and into groundwater. Groundwater can become contaminated when pollutants on the land seep underground; in the Chesapeake Bay watershed, polluted groundwater often pushes nutrients and chemical contaminants into the Bay. Indeed, the slow movement of polluted groundwater into the Bay is lengthening the “lag-time” between the adoption of pollution-reducing practices and the positive effects of those practices on a particular river or stream.

Invasive Species

Water chestnut is an invasive plant that was first spotted in the region in 1923. Volunteer work to remove the floating plant by hand has been integral in keeping populations in check on Maryland’s Bird and Sassafrass rivers.

Invasive species are plants and animals that have been introduced, whether accidentally or on purpose, into their current habitat. Invasive species can cause harm when they establish themselves at the expense of native plants and animals, encroaching on their food or habitat. Blue catfish, the northern snakehead and zebra mussels are three invasive species that can be found in the Chesapeake Bay watershed.


Atlantic menhaden form an important link in the Chesapeake Bay food web. The small fish is harvested commercially for bait and for an industry that uses them to produce fishmeal and fish oil. (brian.gratwicke/Flickr)

Atlantic menhaden form an important link in the Chesapeake Bay food web. The small fish form large schools and are harvested commercially for bait and for an industry that uses them to produce fishmeal and fish oil. To protect this keystone species, fisheries managers have placed a cap on the amount of menhaden that can be harvested from the Bay.


Nutrient pollution fuels the growth of harmful algae blooms that block sunlight from reaching underwater grasses and lead to

Plants and animals need nutrients to survive. But when too many nutrients enter rivers, streams and the Chesapeake Bay, they fuel the growth of algae blooms and create conditions that are harmful for fish, shellfish and other underwater life. In fact, excess nutrients are the main cause of the Bay’s poor health.


Oysters are natural filter feeders: as they pump water through their gills, they trap particles of food as well as nutrients, suspended sediments and chemical contaminants. In doing so, oysters help keep the water clean and clear for aquatic life.

The eastern oyster is one of the most iconic species in the Chesapeake Bay. For more than a century, oysters have made up one of the region’s most valuable commercial fisheries, and the filter-feeder continues to clean our waters and offer food and habitat to other animals. But over-harvesting, disease and habitat loss have led to a severe drop in oyster populations. Scientists are working to manage harvests, establish sanctuaries, overcome the effects of disease and restore reefs with hatchery-raised seed in an effort to bring back the bivalve.

Population Growth

In 2016, an estimated 18.1 million people lived in the Chesapeake Bay watershed. Experts believe this number will continue to rise, surpassing 20 million by 2030. But the health of our waterways is directly tied to population growth.

With its strong economy, diverse communities and rich natural and historic resources, it’s no wonder that just over 18 million people call the Chesapeake Bay watershed home. But the region’s rapid rate of population growth has raised concern over whether the watershed can continue to sustain the plants, animals and people that live here.

Rivers and Streams

There are hundreds of thousands of creeks, streams and rivers in the Chesapeake Bay watershed.

There are hundreds of thousands of creeks, streams and rivers in the Chesapeake Bay watershed. These tributaries send fresh water into the Bay and offer vital habitat to aquatic plants and animals. These tributaries also provide people with public access points where they can fish, boat and swim. While pollution and the installation of dams, culverts and other structures can affect the health of rivers and streams, local cleanups and reductions in polluted runoff can conserve their health.


(Chesapeake Bay Program)

Sediment is made up of loose particles of sand, silt and clay. It is a natural part of the Chesapeake Bay, created by the weathering of rocks and soil. In excess amounts, sediment can cloud the waters of the Bay and its tributaries, harming underwater grasses, fish and shellfish.


American shad once supported the most valuable finfish fishery in the Chesapeake Bay. Today, commercial and recreational shad harvest is closed across most of the region. (Jim Cummins/Interstate Commission on the Potomac River Basin)

American shad are the most well-known river herring in the Chesapeake Bay. Shad form an important link in the Bay’s food web, and once supported the most valuable finfish fishery in the region. But pollution, historic overfishing and the construction of dams that block the migratory fish from reaching their spawning grounds have lowered shad populations. Commercial shad harvest is now closed across most of the region. To restore shad to the region’s waterways, Chesapeake Bay Program partners are working to remove dams and restock rivers with hatchery-raised fish.

Stormwater Runoff

As stormwater flows across streets, sidewalks, lawns and golf courses, it can pick up harmful pollutants and push them into storm drains, rivers and streams. Increased development across the watershed has made stormwater runoff the fastest growing source of pollution to the Chesapeake Bay.

What happens to a drop of rain when it falls onto the ground? It may land on a tree and evaporate; it may land on a farm field and soak into the soil; or it may land on a rooftop, driveway or road and travel down the street into a storm drain or stream. Precipitation in an urban or suburban area that does not evaporate or soak into the ground but instead runs across the land and into the nearest waterway is considered stormwater runoff. Increased development across the watershed has made stormwater runoff (also called polluted runoff) the fastest growing source of pollution to the Chesapeake Bay.

Striped Bass


Striped bass—also known as rockfish or stripers—have been one of the most sought-after commercial and recreational fish in the Chesapeake Bay since colonial times. After bouncing back from a severe decline in the 1970s and 1980s, the striped bass population is now at its highest level in decades. However, scientists are uncertain about the health of the species because of a high prevalence of disease and possible lack of prey.


(Jane Thomas/IAN Image Library)

Hundreds of wastewater treatment facilities throughout the Chesapeake Bay watershed are being upgraded with advanced technology to reduce the amount of nutrients that are discharged into the Bay's tributaries. Wastewater treatment plant upgrades account for a large portion of overall estimated nutrient reductions to date, and Bay jurisdictions are relying on additional reductions from wastewater to achieve about 15 percent of total overall nutrient reduction goals.


Strong storms, like Hurricane Isabel, which hit the Chesapeake Bay in 2003, can lead to flooding in the watershed. Extremes in rainfall—whether too much or too little—can have varying effects on the Bay ecosystem. (Michael Land Photography)

Rainfall, wind and temperature can have wide-ranging effects on Chesapeake Bay habitat, water quality and fish and shellfish populations. While all plants and animals can adapt to periodic changes in environmental conditions, scientists cannot predict with certainty how the region will respond to the prolonged periods of extreme weather that have been linked to climate change.


Wetlands provide critical habitat for hundreds of critters while also improving the health of the Bay by collecting and storing flood waters, filtering polluted runoff and weakening storm surges.

Wetlands are critical in supporting the healthy waters and diverse wildlife of the Chesapeake Bay watershed. Located where land meets water, wetlands act like a sponge, soaking up storm surges and trapping polluted runoff. Wetlands also provide habitat to hundreds of fish, birds, mammals and invertebrates. But development, invasive species and sea level rise threaten these important areas. Protecting and restoring wetlands is a key way to promote clean water, healthy habitats and a restored Bay.

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