Midshore Creekwatchers, a volunteer organization of over 50 members, assists MRC scientists in monitoring nine of our rivers and Eastern Bay. MRC produces a River Report Card annually analyzing the results from over 100 testing sites monitored at least monthly. Additionally, the United States Geological Survey (USGS) has been testing water quality on the Choptank River near Greensboro since 1965, and the EPA Chesapeake Bay Program and Maryland Department of Natural Resources have measured water quality near the Choptank River Bridge since 1984. The results of these important efforts reveal a dramatic, frightening, and steady decline in water quality:
- Water Clarity: Very Poor and Continues to Decline
Turbidity testing measures the ability of light to pass through water. Excess turbidity, or poor water clarity, indicates that light cannot penetrate deeply enough below the surface to support growth of underwater grasses. Light should be able to penetrate at least six feet in a healthy estuary. Over 90% of recent measurements show poor water clarity.
- Nitrogen Pollution: Levels are too high
Excess nitrogen promotes excessive algae growth, which turns water cloudy and dark. Algae decomposes when it dies, sucking oxygen out of the water and creating dead zones. Certain forms of algae are toxic to fish and humans. The amount of nitrogen flowing into the Choptank was twice as high in 2005 as it was in 1985.
- Phosphorus Pollution: Levels are too high
Phosphorus binds to sediment and leads to excess nutrient enrichment of our rivers. As with nitrogen, this causes unhealthy algae growth, poor water clarity, and oxygen-dead zones, a process called eutrophication.
- Oxygen Levels: Occasional Inadequate Oxygen Levels
Dissolved oxygen is essential to all aquatic life. As a result of the above-described problems, over the past decade there has been a consistent decline in oxygen content in our tributaries. We are nearing a crisis where the rivers we cherish may no longer support aquatic life. In 1985 the Choptank supported 3,561 acres of underwater grasses – key habitat for crabs, small fish, and worms. In 2006 the river had just 1,092 acres, about a 70% loss. Underwater grass beds only covered 5% of the area needed to meet the restoration goal.