Much of Fairfield’s coastal neighborhoods consist geologically of sand, unlike other bedrock land areas along the Connecticut shoreline. Fairfield’s low-lying areas are made up of sediments carried south from nearby rivers and washed ashore by the ocean’s movements, creating sandy river deltas and beaches.
Fresh and salt waters intermingle in Fairfield's coastal marshes and wetlands. This creates a unique environment, where 75% of local marine life spends at least a portion of their lives. The salt marsh is a marine nursery, a source of food, and a fulltime home for many species. These wetlands absorb floodwaters and also protect coastal water qualityfiltering nutrients and trapping sediments in the sponge-like peat formed by many years of decaying plant material.