Economics of Beach Nourishment Under Scenario of Rising Sea Level

Abstract

The economics of using coastal structures to retain sand on a beach in conjunction with beach nourishment is presented. As the cost of suitable beach sand increases it becomes more economical to include structures in a project if those structures increase the residence time of the sand on the beach. Expenditures that can be justified to provide structures depend on how long the structures extend the sand's residence time and on the prevailing interest rate. Results are presented graphically for perpetual nourishment projects for the case of a constant erosion rate (a constant rate of sea‐level rise). A correction factor to consider finite lifetime projects is also presented. For the, case where the rate of sea‐level rise continues to increase (as has been projected by several recent studies) perpetual nourishment becomes impossible since the time between successive renourishments decreases. However, nourishment projects with finite lifetimes can be evaluated to establish justifiable structure costs.