Hydrologic Cycle in Coastal Zones

Precipitation either evaporates into the atmosphere, gets taken up by plants, flows into streams, or infiltrates the ground and recharges aquifers. Groundwater flows from inland locations to lakes, streams, or coastal waters. On the seaward side, denser salt water enters sediments and establishes equilibrium with fresh groundwater. Tides and mixing along the freshwater-saltwater interface results in seawater circulation through the sediments. (Illustration by Jack Cook, Woods Hole Oceanographic Institution)