Episodic Saltwater Intrusion: Characteristics and Ecological Implications.

Saltwater intrusion (SWI) is a hydrologic phenomenon that jeopardizes freshwater resources in coastal areas. Although SWI can occur naturally, human interactions with the hydroscape may exacerbate SWI through modification of natural flow paths (i.e. ditching and draining) which allows salt water to flow farther into landscapes than it would under unaltered conditions. Studies on SWI in surface waters have approached this phenomenon from two different temporal scales: as a chronic symptom of sea level rise, or an episodic event driven by wind tides, storm surge, or drought. Our work focuses primarily on episodic events which can act as pulse disturbances to coastal wetlands and neighboring managed landscapes, often resulting in vegetation stress, or in severe cases, mortality. We seek to characterize the differences between wind, storm surge, and drought driven saltwater intrusion events with regards to their hydrologic behaviors. Using 3+ years of hydrometeorological data, we extract individual episodic SWI events, evaluate their characteristics, and discuss their ecological significance in the context of the surrounding landscape. Understanding the differences among these types of SWI events will better aid land managers and residents of coastal landscapes in decision making processes that regard restoring and protecting the land or retreating from it as sea level continues to rise, and storms and droughts become more severe and frequent with climate change.