Changes in Water Flow

In many parts of the country, freshwater is a scarce resource because so many people need it—for their homes, schools, farms, factories, and other uses. Because it is in such high demand, state and local governments continue to search for new, inexpensive supplies of freshwater.

Options include building dams to trap water from rivers, pumping water from the ground, and dredging for new sources of water. Each of these activities can change the timing and amount of freshwater that enters our estuaries, and natural drought cycles only make their effects worse. Reducing the amount of freshwater flowing into estuaries can cause erosion and sedimentation and interfere with fish reproduction, shellfish survival, bird nesting, and seed distribution because the water becomes too salty.