A new and more accurate overfill ratio for beach nourishments and its comparison with James' RA

Abstract

Pranzini et al. (2018) designed a method, for borrowed sediment selection in beach nourishment projects, that solved the problems inherent to James' abacus (1975). However, it suffered in turn from the lack of an overfill ratio. A new and more accurate methodology is presented here to calculate the mentioned ratio. To demonstrate the implications of the new proposed method, the overfill ratios calculated are compared with those obtained using the method of James (RA) for nine beaches and nourished sands with different granulometries. The comparison showed that the method of James (1975) predicted a much larger fraction of the borrow sediment to be unstable, thus requiring higher nourishment volumes to achieve a certain beach width and implying increased economic costs.