The Chesapeake Bay is the largest estuary in the United States. To nature lovers, the bay is a national treasure. Its waters are perhaps best known for blue crabs and oysters. For many years, the Chesapeake Bay area benefited from the Conowingo Dam on the Susquehanna River. When the dam opened nearly 100 years ago, it began controlling the power of water to create electricity for northern Maryland. It also trapped sediments before they reached the bay’s waters. While the old dam is still making electricity, it no longer helps the Chesapeake. It cannot. Behind its heavy walls lie 181 million metric tons of black muck pollutants it has collected since the day the dam opened. Now some people fear that the black muck may be a threat to the bay. Recent heavy rains have shown that muck runoff can move along the sides of the dam and pollute the water.
