This satellite image, shot in the spring of 1987, shows agricultural fields in light tan, woodlands in dark green, wetlands in red-brown, and urbanized areas (appropriately) in steel-blue. Ask yourself how much of this land is in the same state it was four hundred years ago. The answer is: not much. Water runs off cleared land very differently from the way it does off old-growth woodland. We have essentially changed the Bay watershed "from filter to funnel" (note the heavy runoff of silt in the lower western shore rivers, coming from previous rains in the Virginia Piedmont region). Much of CBF's work is focused on restoring the watershed's natural water treatment systems, like wetlands, and in helping farmers find ways to reduce nitrogen pollution from agricultural lands.