Wave-Driven Dynamics Simulation and Sea Level Rise Impact on Shoreline Erosion in Chesapeake Bay, USA

Shoreline erosion is a stress to coastal communities, and this is particularly true under climate change and sea level rise conditions. Understanding the mechanisms controlling shoreline erosion and the ability for future projections are critical for mitigation and planning. A parameterization has been developed to model shoreline erosion based on wave power and shoreline characteristics. The present study couples the shoreline erosion model with the Semi-implicit Cross-scale Hydroscience Integrated System Model (SCHISM) and the third-generation Wind Wave Model (WWMIII) and conducts a long-term (1991–2014) simulation constrained by observed long-term shoreline erosion rates. The model revealed that wind waves inside the Bay are mostly locally formed and influence from offshore wave propagation is limited. Shoreline erosion quantity is comparable to sediment loads from the watershed but composed of more coarse material like sand. Interannual variability of shoreline erosion from weather variation was up to 58 percent from 1991 through 2014. Shoreline erosion has a significant influence on sediment distribution away from riverine inputs, but estuarine turbidity maxima dominate the transitional zones between fresh and salt waters in the tributaries as well as in the main stem Bay. A sensitivity analysis run with 53 cm sea level rise resulted in a 28 percent increase in shoreline erosion due to increases in water depth and wave power.