Millions of beaver ponds and dams once sponsored a lush mosaic of wetlands throughout the Chesapeake region. These slowed and spread and retained water flowing to the Bay from every creek and river, letting it soak in and percolate through the ground. Because beavers have been gone so long — they were trapped out of the Chesapeake watershed by 1750 — there is almost an ‘ecological amnesia’ as to the benefits they conferred, the world they created…how the watershed ‘thought’ for thousands of years.