The Chesapeake Bay is the largest estuary in the United States. This watershed basin encompasses over 64,000 square miles, is home to over 16.6 million people and crosses over parts of Delaware, Maryland, New York, Pennsylvania, Virginia, West Virginia and the entire District of Colombia. The streams and rivers of these regions all flow into the Bay, making our actions around these tributaries extremely crucial to the health of the Bay. There is a land to water ratio of 14:1, which is the largest ratio of any coastal water around the world, highlighting again the importance of our terrestrial behavior on the preservation of this valuable resource (Chesapeake Bay Program 2009). Most of the threats to the Chesapeake Bay are influenced by human behavior. Air and water pollution, development, invasive species, climate change and over-harvesting are just a few of these threats. In this blog, we are going to focus on the problem of runoff and its harmful effects on the Chesapeake Bay.
Runoff and stormwater are said to be the fastest growing source of pollution to the Bay. As we develop, we create more impermeable surfaces such as roads, parking lots, and sidewalks. When water flows down these impermeable surfaces, it picks up trash, fertilizers, pesticides and nutrients, specifically nitrogen and phosphorus. Impermeable surfaces deny precipitation the opportunity to soak into the soil and absorb some of the nutrients and contaminants. We need these natural buffers in place to help slow down the runoff from rapidly infecting the watershed. Runoff can also cause erosion in stream banks, which leads to higher concentrations of sediments in the Bay. This interferes with organisms ability to photosynthesize and clogs the bedrocks at the bottom of the streams where many fish lay their eggs. Phosphorus makes up about 17% of the stormwater in the Bay, and nitrogen and sediments make up about 11% and 9% respectively (Chesapeake Bay Program 2009). As nutrients like phosphorus and nitrogen from fertilizers run into the Bay, they can potentially lead to extreme and unusually rapid algae growth. As this algae then dies, it decomposes and limits the amount of available oxygen for the other aquatic life in the Bay.
In order to prevent some of this runoff from getting into the Bay, there are several things that we, as part of any watershed community can do to reduce runoff. Instead of asphalt and concrete, we can use other construction materials such as wood and bricks to reduce the amount of impervious surfaces in our areas. Also, directing inevitable runoff to areas of vegetation can absorb some of these contaminants in the ground before they damage the water quality. Natural alternatives can replace fertilizers and pesticides high in nitrogen content. While these simple changes don’t seem like much, they certainly add up to help protect and conserve our Bay and all the resources it provides.
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