Two main strategies have traditionally been used to control beach erosion, namely hard stabilization such as wave-breakers, groins and seawalls, and soft stabilization such as beach renourishment. Hard stabilization structures are not always the preferred solution because they impact beach aesthetics and interfere with natural ecosystems by inducing more sand erosion and threatening nesting grounds of native shoreline species. Soft stabilization methods typically have a lower environmental impact. Beach renourishment may be used as a stand-alone technology or combined with other soft technologies such as sandtainers, geotubes, artificial reefs and dune restoration.
In the field of geotechnical engineering, natural biopolymers such as polysaccharides have been used for soil stabilization. Although polysaccharides can directly enhance cohesion of soils, they can also enhance microorganism-induced production of extracellular polymeric substances that augment soil cohesion. In addition, certain vegetable proteins may also enhance sediment cohesion. Based on these principles, Dr. Dahmani developed various PPB formulations that can be used for sand cap stabilization on contaminated sediment and for erosion control of natural and renourished beaches. One PPB formulation, SandFirst (SF), was tested in Progreso in the upper Yucatan peninsula of Mexico on a previously renourished beach. Beach profiles and sand accretion/erosion were monitored for a SF-treated beach section (85 m) and compared to two similar untreated beach sections (controls) located on both sides of the SF-treated beach. Beach profiles were measured on a monthly basis to assess the effectiveness of the PPB treatment in controlling beach erosion. The results indicated that beach width increased in the SF-treated section. On the other hand, the control sections displayed continued erosion. Moreover, the erosion/accretion rate in the treated section was +0.06 m3/m, whereas in the non-treated section the rate was -4.04 m3/m, which is consistent with reported erosion data in neighboring coastal areas. Our findings suggest that using PPBs may be a promising eco-friendly method for enhancing renourished beach retention.
Project: Beach Erosion Control
Location: Progreso, Mexico
Services: Environmental Engineering