Mangroves not only afford natural coastal protection, they also provide resources for various products such as fish and fuel, and provide livelihood to coastal communities. In the Philippines, notwithstanding the country’s vulnerability to typhoons and other ocean hazards, mangrove areas have decreased at an estimated rate of 4.7 ha annually since the turn of the 20th century.

Community-based efforts have recently attempted to reverse this anthropogenic process by engaging peoples’ organizations in rehabilitating coastal mangrove areas. These include inland nursing and subsequent coastal transplanting of young mangrove saplings. Monitoring of recent implementations indicate however that these activities result in low success rate due to the large uncertainty in ensuring the saplings’ survival before they reach the minimum growth stage to withstand the natural environment, particularly when exposed to the high waves of typhoon-frequented coastlines.

This paper aims to present studies, analyses, engineering design and implementation of the protection works for a coastal mangrove rehabilitation program in one of several areas in Central Philippines. The analyses and engineering design are based on numerical simulations of wave and tide loadings, accounting for the magnitude and approach directions of historical storms.

The results indicate that waves and tides characteristic of the site can be quantitatively evaluated before undertaking the design of protection works, to eliminate unfeasible solutions, and adapt the feasible ones to the project objectives. It is concluded that a scientific approach is necessary to evaluate the critical loadings and provide quantitative bases for assessing economic design schemes for the rehabilitation structures.