Background The ChesapeakeBay is the nations' largest estuary, a place where salt water from the ocean meets fresh water from rivers. The Bay's importance is reflected in the early names that were given to this body of water: " Great waters," "Mother ofWaters" and "Great Shellfish Bay."
Throughout history, the Bay as played an intergral part in the lives of the people around it. To the Susquehannock Indians lliving in the 1600's the Chesapeake waw a source of delightful food as well as a pathway for enemies, the Piscataways. Soldiers in the War of 1812, fought many bloody battles on the waters of the Chesapeake. Coffee merchants in Baltimore in the earyl 1900's depended on the arrival of ocean going vessels for their livelihood.
Geologically speaking, the Chesapeake Bay is very young. It was created some 12-18,000 years ago as the galciers retreated and polar ice caps shrank cause huge volumes of melting ice to raise sea levels. The rising ocean engulfed the coaset and flooded the river vally of the ancient Susquehanna river,creating the Chesapeake Bay. Today the Bay is nearly 200 miles long, drains a 64,0000 mile basin and is fed by 48 major rivers and 100 small tributaries. Not only have the shorelines been redrawn by ocean waves but also by people clearing the land. Over clearing the land and poor land management has increased upland erosion sending tons of sediment downstream.
Saltwater mixes intothe Bay from the Atlantic Ocean. Freshwater flows from the Bay's tributary rivers, with 50 percent coming from the Susquehanna River. Saltwater is heavier than freshwater, so it tends to "creep" up theBay along the bottom while the freshwater flows down fromthe tributaries from the surface. Because of this the Chesapeake ranges from totally freshwater areas in the North and upstream in its rivers, to areas near the Bay's mouth that are about as salty as the ocian. The overall proportion of fresh and salt water in the Bay depends largely on the amount of rainfall that us carried to the Bay from the Chesapeakes'major rivers. During a year with a great deal of rainfall, the entire Bay will be somewhat fresher than normal. In a dry year the Bay will have higher than average salinities.