Seasonality of Retreat Rate of a Wave-Exposed Marsh Edge

ariela — Tue, 10 Sep 2024 22:59:06 +0000

Seasonality of Retreat Rate of a Wave-Exposed Marsh Edge ariela Tue, 09/10/2024 - 15:59

Document Category

Scientific Reports

Author(s)

Date

2024-07

Summary

Abstract

Wave-driven erosion of marsh boundaries is a major cause of marsh loss, but little research has captured the effect of seasonal differences on marsh-edge retreat rates to illuminate temporal patterns of when the majority of this erosion is occurring. Using five surface models captured over a study year of a marsh with a steep escarped boundary in South San Francisco Bay, we find a pronounced seasonal signal, where rapid marsh retreat in the spring and summer is driven by a strong sea breeze but little change is found in the marsh-edge position in the fall and winter. We found accretion in the mudflat transition region close to the marsh boundary in the calmer seasons however, suggesting intertwined morphodynamics of mudflats and the eroding marsh-scarp. We observed large spatial heterogeneity in retreat rates within seasons, but less on longer (annual and decadal) timescales. The relationship between marsh-edge retreat rates and properties of the wave field nearby is explored and contextualized against extant relationships, but our results speak to the difficulty in addressing spatial erosion/accretion variability on short (seasonal) timescales with simple models.

Key Points

A unique seasonal data set exposes strong seasonality in marsh-edge retreat, with rapid retreat during warm periods with strong sea breeze
There is large variation in retreat rates across the marsh seasonally but more uniform retreat rates on annual and decadal timescales
Digital surface models provide insight into erosion and accretion simultaneously across the marsh-mudflat system

Keywords

Pond Complex