Fifty Years from Earth Day One in the Chesapeake Bay

Fifty Years from Earth Day One in the Chesapeake Bay

By Joel Dunn, President & CEO

Earth Day “One”, April 22, 1970 was a critical inflection point in human history. The first Earth Day event that took place fifty years ago marked a collective realization – for perhaps the first time in all of human history – that the scale and spectrum of humanity’s impact on the environment has had devastating consequences for nature. Earth Day 1970 was a universal call to action for every person to stand up for their environment and for their world. This call to action certainly reverberated strongly here in the Chesapeake Bay.

Where we were in 1970

By April 22, 1970, there was a growing awareness that human waste and pollution inputs into the Chesapeake Bay and its waterways were negatively impacting the Bay and its fisheries. However, the origins of pollution and how it affected water quality, underwater grasses, and wildlife was largely unknown. In addition, the science and tools needed to investigate and understand these problems were limited. Policy measures to address pollution were also exceedingly limited, as the bedrock laws that guide environmental protection today were just starting to be considered by Congress.


What was known and seen by scientists, watermen, and everyday citizens was that the Chesapeake Bay was in trouble. Underwater grasses which were once in abundance throughout the Chesapeake Bay began to disappear. Crystal clear waters of the Bay’s tributaries and shores were becoming noticeably murky. Algal blooms and red tides were increasing in size and occurrence, causing big fishkills. By 1970, poor water quality and the disappearance of underwater grasses was having an impact on the Bay’s fisheries.


Oyster populations, already been devastated by overfishing during the oyster boom of the 19th and early 20th century, were further ravaged by a new parasite, MSX, which affected up to 90 percent or more of all oysters in the lower Bay.

Blue crab landings from the late 1960s through the early 1980s experienced a period of relative decline. The rockfish population began the 1970s at a high point, but would soon plummet in the mid-1970s and early 1980s due to poor water quality and overfishing.

Pollutants into the Bay, which include agricultural pesticides, were deeply affecting wildlife above the water. The iconic bird species found in the Chesapeake Bay – ospreys, peregrine falcons, and bald eagles – were disappearing due to the widespread use of pesticides DDT and PCB.


The landscape of the Chesapeake Bay watershed had also begun to change significantly after World War II. An increase in car ownership among families allowed for easier travel to urban centers. Thousands upon thousands of acres of forest land and farm land were converted into housing and roadways. For example, suburban sprawl combined with large population growth in the region led to approximately one million acres in Maryland being developed between 1973 and 2010.[1]

Science and tools

By 1970, the Chesapeake Bay had already been the subject of considerable scientific research. Pollution from urban centers, agriculture, and industry had had significant negative impacts on the Chesapeake’s fisheries in the 20th century, and this inspired the first studies of sanitation and water quality impacts on the Bay. However, the idea of considering the Chesapeake Bay and the watershed as a whole, singular system was still a relatively new concept. Additionally, the means by which scientists could examine such an enormous and complex ecosystem were severely limited.

One of the most emblematic examples of this limitation was the miniature replica of the Chesapeake Bay watershed called the “Chesapeake Bay Hydraulic Model,” which was authorized by Congress in 1965 and completed in 1978.[2] The physical replica extended nine acres and was, compared to the computer models of today, a crude and extremely costly method for scientists to try and model the impacts of water use, flooding, pollution, and dredging on the Chesapeake Bay. The advent and rapid development of computers quickly eclipsed the need for physical models and have subsequently allowed for improved modeling at a lower cost.


Federal and state government action to restore and protect the Chesapeake Bay have their origins in the decade leading up to Earth Day, but the regulations that largely guide environmental protection today – the Clean Water Act, the Clean Air Act, the Endangered Species Act, the National Environmental Policy Act – had either not been passed in the form we know today or were only recently passed by Congress in the years leading up to Earth Day One in 1970.

Senator Joseph Tydings of Maryland began introducing legislation in the 1960s to require the study of pollution in estuaries and advocating for funding to complete studies like the Chesapeake Bay Hydraulic Model.

States were also beginning to coordinate policy efforts internally, but it would be another decade before Virginia and Maryland came together to create the Chesapeake Bay Commission, the multi-state legislative policy entity that now leads in informing and enacting state level policy concerning the Chesapeake Bay.

Earth Day 2020

The spirit of Earth Day One – a belief that by speaking up and acting together, we can change the state of our world – has only strengthened over time in the Chesapeake Bay region.

Fifty years later, the Chesapeake Bay is home to one of the largest, most coordinated, and most dedicated conservation and restoration efforts in the entire world. Citizens, scientists, non-profits, for-profits, and governments at every level are working together to reduce pollution into the Chesapeake Bay and its waterways, and to protect the iconic species of the Bay along with nature and wildlife throughout the Bay’s watershed. Our knowledge of the causes of environmental degradation, and our approaches to solving these problems, has improved beyond measure.

The Chesapeake Bay and the watershed still face daunting challenges that must be addressed, but we have made remarkable progress since Earth Day One. Currently, just over 22 percent (more than 9 million acres) of lands have been protected from development across the watershed.

Coordinated and collective action among all partners has led to significantly improved water quality in many tributaries and areas of the Chesapeake Bay. Underwater grasses have rebounded in recent years to as much or more than a 316% increase over a forty year period.[3] Water clarity has improved in some areas. After being nearly wiped out, the osprey, falcons, and bald eagles have made a remarkable comeback.

Fisheries have continued to hit high and low points over time, but the scientific link has now been well established between habitat quality, fisheries management, and the population of crabs, oysters, and striped bass among the Chesapeake’s other important aquatic species.

The connection between our land use and the health of the Chesapeake Bay itself and its wildlife is also well understood, and the protection of natural lands is incorporated in the effort to restore and protect the Bay.

Our ability to study the Chesapeake Bay and understand how our actions impact its health has also improved dramatically. Data collected and organized by water quality and air quality instruments, satellite imagery, geographic information systems (GIS), and artificial intelligence now guide the computer models that help scientists track the health of our watershed. Research that may have taken a decade to complete in 1970 can be done in a matter of months or faster.

All this progress would not have been achieved without federal, state, and local policies and cooperation to reduce pollution and limit our impact on the Chesapeake Bay, its species, and its many ecosystems. The multi-jurisdictional Chesapeake Bay Watershed Agreement and the partnership between federal and state agencies, local governments, non-profits, businesses, and everyday citizens has allowed for extraordinary advances in the science and governing to protect the Chesapeake Bay.

Where we are going

The rich ecosystem of partners committed to the health and restoration of the Chesapeake Bay, the policy framework and governing structure that guides these efforts, and the science and tools available will enable even greater progress. However, the pollution problems identified and studied fifty years ago are now compounded by the new reality faced here in the Chesapeake Bay and across the world, which is global climate change. Climate change has already begun to alter species and ecosystems, and it will have a fundamental and profound impact over the coming years.

Just as Earth Day One was an ambitious and spirited call to action, partners in the Chesapeake Bay must answer the threat of climate change with an equally ambitious goal to protect our region’s greatest natural treasure.


[1] “A Summary of Land Use Trends in Maryland.” The Maryland Department of Planning, 2010,, Accessed 21 April 2020.

[2] Daniel Pendick. “The Rise and Fall of the Metapeake Monster.” Chesapeake Quarterly., Accessed 21 April 2020.

[3] Jonathan S. Lefcheck et al. “Long-term nutrient reductions lead to the unprecedented recovery of a temperate coastal region.” Proceedings of the National Academy of Sciences of the United States of America. 115, 14, 2018, pp. 3658-3662