A changing estuary: Understanding historical patterns in salinity and fecal coliform levels in the May River, SC.

The May River, South Carolina watershed has undergone rapid increases in population and development from 1999 to 2017. This study aimed to understand the factors that influence salinity and fecal coliform levels in this estuary and how these levels changed from 1999 to 2017. This analysis revealed that salinity levels decreased in the headwaters, while variability increased. Additionally, fecal coliform increased from 1999 to 2017 throughout the hydrological network, with drastic changes occurring in the headwaters. Salinity and fecal coliform were influenced by spatial (distance from the mouth of the river), temporal (year, season, and tidal cycles), environmental (El Niño Southern Oscillation and rainfall), and anthropogenic parameters (population). This analysis suggests that the synergistic nature of climate change, resulting in more intense and frequent El Niño events, and watershed development may lead to further decreases in salinity and increases in fecal coliform levels in the May River estuary.