22-12 Dynamic reorganization of coastal catchment boundaries in response to sea level rise

Session: Advances in characterizing groundwater, surface water, and their interactions (Posters)

Presenting Author:

Authors:

Abstract:

Coastal catchments, which drain directly to the sea, mediate material fluxes across the land-sea interface and support species diversity and economic activity in coastal zones. In this study, we explore the evolution of coastal catchment divides at the local to global scale from 2000 to 2120 under multiple SLR scenarios using state-of-the-art digital terrain and hydrographic models. We show that coastal catchment area loss following inundation is partly counteracted by inland migration of coastal catchment boundaries and new coastal catchment formation. Encroaching shorelines intercept runoff from interior watersheds. Runoff within these shoreline runoff capture windows bypasses stream networks and discharges directly to the ocean, resulting in net coastal catchment growth along 14% of the world coastline within a century, even under high sea level rise. Contrary to the notion of static watershed divides, these findings reveal a counterintuitive tendency of geologically rapid expansion and reshaping of coastal catchments in future decades.

Geological Society of America Abstracts with Programs. Vol. 58, No. 2, 2026

© Copyright 2026 The Geological Society of America (GSA), all rights reserved.