Our Bay: This Week's Take: Conowingo Dam: Disaster in waiting

The Susquehanna is arguably the most important river in the Chesapeake Bay's watershed. Its two branches drain 27,500 square miles of the bay's entire 64,000 square mile watershed.

By the time the river reaches the bay at Havre de Grace, Md., it has traveled 448 miles and will deliver 25 billion gallons of water to the bay on an average day.

But there are no average days.

Water flow ranges from a record 650 billion gallons in a single day to less than 2 billion during a drought. Over the course of a year, half of the fresh water that's so vital to an estuary such as the Chesapeake comes down the...