Devereux Slough, located on California’s South Coast near Santa Barbara, is a small seasonal estuary spanning approximately 0.4 square miles within a 2.5-square-mile watershed. During dry months, a sandbar often forms at the slough’s mouth, blocking tidal exchange and creating a dynamic lagoon environment. Water levels, salinity, and oxygen conditions shift throughout the year, influencing a range of aquatic and terrestrial habitats.

The slough provides important habitat for migratory birds, native fish, amphibians, and coastal vegetation, and is part of the protected Coal Oil Point Reserve. It is recognized as a valuable site for wildlife conservation, education, and research. However, surrounding urban development and recreational activity can affect water quality, sediment dynamics, and the natural flow of freshwater into the system. Seasonal closures also raise the potential for flooding during major rain events, especially when water becomes trapped behind the sandbar.

Water level monitoring at Devereux Slough helps track seasonal patterns, sandbar behavior, and flood risk. These data support restoration and conservation efforts, inform land and water management decisions, and help protect the ecological health of this sensitive coastal system amid ongoing human pressures.