Tuesday July 23, 2024
USGS via Maven’s Notebook —
Erosion of marsh boundaries by waves is a major cause of marsh loss, but little research has captured the effect of seasonal differences on marsh-edge retreat. A new study conducted by scientists at the United States Geological Survey (USGS) and the University of California, Berkeley, shows how seasonal climate variations influence the rate of marshland erosion due to wind-driven wave activity.
The study, published in the Journal of Geophysical Research: Earth Surface, focused on Whale’s Tail Marsh South in South San Francisco Bay. The researchers constructed five detailed 3D models of the marsh surface using aerial photos collected with a fixed-wing aircraft and photogrammetry techniques, capturing its state during summer, fall, winter, and spring over a single year. By comparing these models, they observed distinct variations in marsh loss depending on the season:
- Spring and Summer: The rate of marsh loss was notably high during these seasons, characterized by strong daily winds. The constant wave action generated by these winds led to accelerated erosion at the marsh boundaries.
- Fall and Winter: In contrast, during the stormier fall and winter months, the rate of marsh loss was considerably slower. Despite the presence of storms, the absence of persistent daily winds resulted in less erosive wave activity.