Assessment and Monetary Valuation of the Storm Protection Function of Beaches and Foredunes on the Texas Coast

Beaches and dunes dampen wave energy and protect against storm surge. This protection is not uniform and varies according to geomorphic characteristics along the coast. Barrier island communities should identify the protection afforded by beaches and dunes to better assess their vulnerability and inform decision making regarding management alternatives. Our study presents a classification identifying a theoretical level of protection that beaches and foredunes could provide against overwash resulting from a tropical storm or hurricane along Mustang and North Padre Islands, Texas. In addition, a monetary valuation of this protective function is estimated at a site level. The theoretical level of storm protection was determined by assessing the response of representative beach-dune profiles to a set of synthetic storms and identifying the storm level at which profiles were overwashed. A monetary value was then assigned to the storm protection function of beach-dune profiles using a replacement cost approach. The level of protection afforded by beaches and foredunes varies across the islands. Some areas are more vulnerable to overwash and inundation during low-intensity storms. About 50% of the assessed beach-dune profiles provide overwash protection against at least a 100-year storm. Areas with the highest protection levels (100 and 200 y) share the following characteristics: (1) they have high dunes (>4 m in elevation), (2) they are in largely undeveloped areas or where buildings are at least 150 to 200 m landward of the line of vegetation, and (3) they generally have a wider beach-foredune complex width. The total annual value of the storm protection function of beaches and foredunes is estimated to be $141.4 million (USD 2013, replacement cost equivalent).