Southeastern Section - 50th Annual Meeting (April 5-6, 2001)

Paper No. 0
Presentation Time: 8:00 AM

BEACH NOURISHMENT: TWO SIDES TO EVERY STORY


PILKEY, Orrin H., Division of Earth and Ocean Sciences, Duke Univ, Durham, NC 27708, opilkey@geo.duke.edu

Beach nourishment is now the preferred erosion control alternative for most U.S. open shorelines. The popularity of beach nourishment stems from the wide recognition that construction of seawalls leads to beach loss. The immediate reason for most nourishment projects is erosion-endangered beachfront property. The actual justification stated for public consumption is the need to provide a wide recreational beach. In fact, if the buildings are either moved or demolished, a wide beach will always be present as the shoreline retreats. A typical major nourishment project amounts to a cost of around $10,000 per beachfront building per year. The proposed North Carolina Outer Bank nourishment project is predicted to cost in excess of $30,000 per property per year. The point is that the erosion problem and the resulting need for nourishment is caused by imprudently sited buildings. No threatened buildings-no erosion problems, an important consideration in determining who should pay.

There are many other considerations. Prediction of beach durability for first time beaches has proven to be unsuccessful because of, among other things, the random occurrence of storms. Mathematical models have been particularly unsuccessful in prediction, and have proven to be vulnerable to political manipulation to justify favorable cost ratios of projects. Ecological damage caused by beach nourishment is poorly understood - long term studies on sandy coasts are lacking. Eventually, sea level rise can be expected to increase the rates of nourished beach loss. By 2050, it may well be that the huge costs of beach nourishment will cause societal priorities to shift from open ocean recreational property to the protection of major coastal cities, such as Manhattan and Miami.