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Abstract Floodplain inundation has been viewed as a type of binary process set by the relative elevation between river stage and levee crest. However, recent reports in the literature show that this perception may have limited applicability. In particular, through‐bank channels, conduits that cross the main river levees or banks, facilitate conditions for an “inundation continuum,” or inundation for a range of sub‐bankfull flows. Moreover, through‐bank channels and their networks provide a direct hydraulic connection between the main river and the floodplain interior. We analyzed through‐bank channel structure and floodplain topography and compared them to river surface elevation to provide greater insight on floodplain inundation processes. Results show that well‐developed levees with through‐bank channels facilitate frequent through‐bank inundation. Where levees are poorly developed, floodplain inundation occurs by overbank flow. Therefore, for a given discharge through‐bank and overbank inundation may occur simultaneously. For the Congaree River floodplain, we infer that this dichotomy of inundation processes leads to temporally and spatially complex inundation flow paths for a given river stage. Further, our analyses reveal that the inundation continuum concept should be considered in the context of having vertical, longitudinal, lateral, and temporal components.
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This content will become publicly available on December 1, 2025
Flood teleconnections from levees undermine disaster resilience
Inland levees can amplify flood risk in unprotected communities by altering floodwater levels away from their location. While these nonlocal effects of levees, which we term flood teleconnections, have been studied for specific river segments, their impact on flood risks along a river network remains underexplored. By combining data-driven, hydrodynamic, and economic models, we quantify the magnitude, spatial distribution, and economic damages associated with flood teleconnections for a large river network system with extensive levees. We find that due to levees, the 100-year flood inundation extent grows by 25% of the total levee-protected area regionally, and the flood inundation depth increases by up to 2 m at specific locations. Levees also increase the vulnerability of unprotected, marginalized communities to flooding. Our results demonstrate that flood teleconnections are spatially widespread, involve unaccounted costs, and can lead to flood inequities. These findings will be critical to climate adaptation efforts in flood-prone regions.
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- Award ID(s):
- 2332169
- PAR ID:
- 10525558
- Publisher / Repository:
- Springer Nature
- Date Published:
- Journal Name:
- npj Natural Hazards
- Volume:
- 1
- Issue:
- 1
- ISSN:
- 2948-2100
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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