Beach nourishment impacts on the beach profile
Date
2016
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of Delaware
Abstract
The Delaware coast has been nourished since the early 1960s as a countermeasure for the eroding pattern that is observed on most of Delaware beaches. The beaches that were nourished are Rehoboth, Dewey, Bethany, South Bethany and Fenwick Island. Beach users have reported that nourishment projects affected the beach morphology and resulted in different surf zone characteristics. The available surveys date from the 1960s were analyzed to determine if those observations are justified from bathymetric change. The profile is divided in parts according to morphological characteristics to determine where the profile is most affected and what the consequences are. The long term evolution of the profile is evaluated from annual surveys and is compared with the variation of the profile over a summer season. The relationship of wave conditions, sediment characteristics and the resulting beach slope are investigated to explain the variability of beach profile slope over short time periods. The assessment of the impact of beach nourishment also includes the use of numerical models. Specifically, XBeach is used to simulate the morphological evolution of beach fill during storm conditions. XBeach was calibrated and validated with pre- and post-storm surveys, and different fill scenarios were simulated to determine the most appropriate nourishment practice for the Delaware coast. The fill scenarios include different fill grain size, fill template slopes, berm height, and fill volume as well as the placement of submerged fill.