Document Type

Article

Publication Date

2023

DOI

10.1007/s12237-023-01245-3

Publication Title

Estuaries and Coasts

Volume

Article in Press

Pages

1-21

Abstract

Due to sea level rise, tidal flooding is now common in low-lying coastal systems around the world. Yet, the contribution of tidal flooding to non-point source nutrient loads and their impact on the quality of adjacent waters remains poorly constrained. Here, we quantified dissolved nutrient loading and Enterococcus abundance during annual autumnal king tides (i.e., perigean spring tides), between 2017 and 2021, in a sub-watershed of the lower Chesapeake Bay. To calculate nutrient loading from tidal flooding, we used geospatial inundation depths from a street-level hydrodynamic model to estimate floodwater volumes during each of the five sampling events and the difference between nutrient concentrations in floodwater and pre-flood measurements. Results showed that dissolved nutrient concentrations were higher in floodwaters than in estuarine waters and resulted in dissolved nitrogen and phosphorus loads that reached 58.4 × 103 kg and 14.4 × 103 kg, respectively. We compared our load estimates to the tributary-specific total and land-based federal allocations (i.e., total maximum daily loads (TMDL)) for total nitrogen (TN) and total phosphorus (TP). Even the more conservative calculations indicate that inputs of dissolved nutrients during a single tidal flooding event can exceed 100% of the annual load allocation. Additionally, more than 80% of the floodwater samples collected each year showed Enterococcus abundance that exceeded the threshold for recreational water use in Virginia (104 MPN 100 ml−1). Failing to account for non-point source loading of nutrients and contaminants from tidal flooding as sea level rises could result in worsening eutrophication and deterioration of coastal economies and the health of coastal communities around the world.

Rights

© 2023 The Authors.

This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third-party material in this article are included in the article's Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.

Original Publication Citation

Macías-Tapia, A., Mulholland, M. R., Selden, C. R., Loftis, J. D., & Bernhardt, P. W. (2023). Five years measuring the muck: Evaluating interannual variability of nutrient loads from tidal flooding. Estuaries and Coasts. Advance online publication. https://doi.org/10.1007/s12237-023-01245-3

ORCID

0000-0001-8819-189X (Mulholland)

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