Breakwater technologies, thoroughly studied by the Army and the Navy, are designed to attenuate wave height and dissipate wave energy to prevent or limit wave run-up or shoreline erosion. Breakwaters can be submerged or floating and can be grey (man-made) or green (nature-based). Breakwater design does not currently account for sea spray aerosolization as an impact of implementation. Aerosol deposition modeling is a robust field capable of theoretical and experimental validation. The effect of structures such as grass, trees, and buildings on aerosol transport and deposition is well studied. Mutually beneficial effects can be wrought from the design and implementation of these structures for coastal and corrosion engineering. This project effort will implement technologies to reduce corrosion severity at coastal sites and harmonize previously siloed fields to arrive at engineered solutions which will benefit all disciplines.

To mitigate corrosion, the project will reduce the production, transport, and deposition of sea spray aerosols (SSA). Successful corrosion mitigation will be verified through environmental monitoring and validated with physics-based modeling. Corrosion severity will be monitored with corrosion coupon and sensor technology. Aerosol concentration and deposition will be monitored with airfoil deposition plates and optical particle sizer and corrosion sensor instrumentation. The generation, transport, and deposition of salt-laden SSA at a shoreline will be modeled with computational fluid dynamics. The wave action at the coastal environment will be modeled with the Shallow Water Environmental Database platform. Meteorology (temperature, relative humidity, wind, etc.), oceanography (wave height/length, salinity, etc.), salt deposition, and corrosion severity will all be measured. Sea-based engineering solutions (e.g., submerged or floating breakwaters) will be implemented to attenuate wave energy and reduce the production of SSA. Land-based engineering solutions (e.g., natural or artificial vegetation) will be implemented to increase the surface roughness, thereby decreasing the surf-accelerated corrosion zone.

Successful corrosion mitigation will be gauged by the ability for land-based and/or sea-based technologies to reduce the corrosion severity by a value of at least 1.0 using the Naval aviation enterprise internal environmental severity indexing (ESI) framework. The framework was developed to characterize the corrosion severity of different air stations around the world. The framework will be improved with the addition of salt deposition measurements and integration of coastal processes into the consideration of ESI.

The corrosion strategy of the Department of Defense (DoD) currently considers the baseline severity of a site as a given and focuses on altering the material selection and design of assets (to be more corrosion resistant) and/or altering the maintenance and sustainment practices (to offset the effect of corrosion). Instead, this technology has the potential to alter the baseline corrosivity on a site-by-site basis and save time, money, and resources across multiple platforms and services. The solutions also offer benefits to increase the resiliency of DoD installations by protecting shorelines against erosion and improving the ecological value of the land and water through natural means (living shorelines, tree planting, etc.). Corrosion engineering should be considered for future implementation of coastal technologies on coast-adjacent DoD installations. Other potential benefits include training use, recreational use, energy production/resilience, and aesthetic appeal.