Proceedings of the 2023 Mississippi Water Resources Conference

Year: 2023 Authors: Peterson D., Jones C.N., Wolford M., Zarek K., Speir S.

Non-perennial streams (i.e., streams that dry regularly) comprise over 50% of the global river network and play an important role in influencing the physical, chemical, and biological characteristics of downstream waters. In the Southeastern United States, non-perennial streams occur in the headwaters of river networks, and their unique patterns of drying have not been well-characterized. In these systems, heterogeneity of watershed physical features, including stream slope, subsurface architecture, and preferential flowpaths, play a key role in spatial and temporal variation in streamflow and drying. Our goal is to develop a predictive understanding of spatiotemporal patterns of stream drying across watersheds representative of three distinct physiographic regions in Alabama: the Coastal Plain, Piedmont, and Appalachian Plateau. We characterized longitudinal network connectivity over an annual drying cycle with empirical water presence data collected using Stream Temperature Intermittency and Conductivity (STIC) loggers dispersed throughout the watersheds. We also characterized watershed structural features, including elevation, slope, soil depth, and valley shape, using publicly available data. Combining these data sources allowed us to compare spatial and temporal patterns of network drying to identify potential drivers. Our initial results suggest that each physiographic region may have a unique drying regime, and that drying occurs hierarchically within watersheds. Our work provides insight into the drivers of stream drying in the Southeast, better informing our understanding of the structure and function of these important stream networks.