Factors Impacting Bay and Watershed Health
The Chesapeake Bay is affected by multiple factors, ranging from population growth to climate variability, which will challenge the recovery of this important ecosystem.
- Natural Factors: Total river flow to the Bay during the 2007 water year (October 2006-September 2007) was very close to the long-term average despite several months of extremes. Climate change and variability have caused water temperatures in the Bay to exhibit greater extremes during the 20th century than the previous 2,000 years. Sea-level rise related to climate change is contributing to the loss of vital coastal wetlands.
- Pollutants: Pollutant loads continue to exceed target levels established to restore the Bay's water quality.
- Land Use: The human population in the Bay watershed is now growing by about 130,000 residents annually. The cumulative impact of centuries of population growth (currently nearly 17 million) and landscape changes has taken its toll.
- Fisheries Harvest and Pressures: Historic over-harvest, compounded by the impacts of poor water quality, disease and blocked access to historic spawning grounds, has resulted in low abundances of oysters, crabs and shad.
- The Bay's watershed covers an enormous 64,000-square-mile area that includes parts of six states – Delaware, Maryland, New York, Pennsylvania, Virginia and West Virginia – and all of the District of Columbia. The way nearly 17 million watershed residents live and use natural resources greatly influences Bay and watershed health, which includes hundreds of local creeks, streams and rivers.
- Population growth and agricultural lands have contributed to an overabundance of nutrients, sediment and contaminants entering the Bay, and loss of habitats that can retain these pollutants.
- Climate change and variability have caused water temperatures in the Bay to exhibit greater extremes during the 20th century than the previous 2,000 years. Sea level rise related to climate change is contributing to the loss of vital coastal wetlands.
- Historic over-harvest, compounded by the impacts of poor water quality, disease and blocked access to historic spawning grounds, has resulted in low abundances of oysters, crabs and shad. The cumulative impact of pollutants, habitat loss, over-harvesting, invasive species, climate change and disease has affected the health of fish and bird populations in the Bay and its watershed.
- In Factors Impacting Bay and Watershed Health, the most current monitoring data available are used to provide an assessment of various factors impacting the health of the Bay and its watershed.
- Factors impacting Bay and watershed heath are tracked with 14 “reporting-level” indicators grouped in four priority areas that represent major stressors to the Bay ecosystem.