Forging sustainability

Sandtrack - Beach nourishment: an integrated methodology for coastal management support
Coordinator - Paulo A. Silva
Programme - Projetos de Investigação Científica e Desenvolvimento Tecnológico (02/SAICT/2017)
Execution dates - 2018-08-10 - 2021-08-10 (36 Months)
Funding Entity - FCT - Fundação para a Ciência e a Tecnologia
Funding for CESAM - 174402 €
Total Funding - 239314 €
Proponent Institution - Universidade de Aveiro
Participating Institutions
Instituto Hidrográfico

Artificial beach nourishment constitutes an effective and environmental friendly protection that guarantees existing standards of coastal defence and management against coastal erosion while preserving beach recreational values. To improve the design and performance of such operations, a comprehensive understanding of the processes governing nourished beach evolution is needed. The quantification of morpho-sedimentary changes involving artificial sand nourishments has several constraints, namely, the poor temporal resolution of traditional topobathymetric surveys [1]. The complementary use of sedimentary tracers (e.g, fluorescent tracers) to evaluate sediment transport directions can be considered a valuable tool [2], [3] but there are drawbacks related to global logistics and sampling methods [4]. On the other hand, the complexity of the physical processes in the nearshore (wave transformation) and the morphological changes occurring at short-time scales, determining the beach profile, and in long-term, determining the shoreline evolution, make it difficult to accurately predict the morphodynamics using existing numerical models. Here we propose to develop an innovative multidisciplinary approach combining the use of fluorescent and magnetic sand tracers, as well as numerical modelling, to monitor and quantify the sediment transport and to improve the efficiency of artificial nourishments of submerged beaches. This approach is applied to the case study of the Costa Nova-Aveiro where shots of several million cubic meters are foreseen [5]. The methodology consists in: (i) Spatial and temporal monitoring and quantification of sediment transport rates by using fluorescent and magnetic tracers. Contrarily to conventional studies that use paramagnetic (weakly magnetic) sands, the innovative and promising aspect of this approach is to manufacture ferromagnetic (strongly magnetic) tracers by using natural sands previously painted with a magnetic ink. Coupling it with traditional fluorescent tracers, for which the research team has extensive experience [6,7,8], one ensures the validation of the magnetic method. (ii) A well-known morphodynamic model DELFT3D [9] and a new forecasting tool for shoreline evolution LTC [10,11,12] will be applied to describe the motion of nourished sands in different conceptual scenarios. The calibration/validation of the numerical results with the data acquired during the project will allow to improve several processes in the models, namely, the coupling between the cross-shore beach profile CS-model [13] with shoreline evolution longterm in LTC and to address the transport of heterometric sediments and lagrangian sand particle tracking modelling [14] in DELFT3D model. The project results will contribute to evaluate the effectiveness of beach nourishment interventions towards a more efficient management of public financial resources and they will also have important implications for risk and natural hazard management.

Members on this project
Paulo A. Silva
Tiago Abreu

CESAM Funding: