Partrac were contracted by Angus Council in the spring of 2015 to evaluate the use of dredge material to trickle recharge the beach at Montrose, North East Scotland. To assess the efficacy of the proposed scheme, a study was conducted to map the sediment transport pathway(s) of a small volume of dredge material (sand) following emplacement in a drop zone offshore of Montrose beach.
To monitor the spatiotemporal distribution of the dredge material following disposal Partrac utilised an active sediment tracing method. This technique utilises geological analogues called ‘tracers’. Partrac’s proprietary dual signature tracers are natural sediments tagged with two unique signatures (fluorescence and ferrimagnetism) which, in this study, were designed to match the hydraulic properties of the dredge material. The applied signatures enable the tracer particles to be tracked through time and across space allowing the sediment transport pathways of these sediments to be mapped.
Partrac’s tracer proved to be an effective tool to elucidate local sediment transport pathways. The year-long study which encompassed an extensive onshore and offshore sampling campaign demonstrated sediment transport at the site was multi-directional. An onshore transport pathway from the dredge disposal zone to the beach face was unequivocally determined and the findings of the study indicated that the disposal of dredge material in this fashion was potentially beneficial as a best practicable environmental option (BPEO) for the disposal of dredge material, contributing to the management of coastal erosion.
Kevin Black, Technical Director at Partrac commented, “In confirming an onshore sediment transport pathway at the site this study provided validation of the potential use of dredged material to trickle feed sediment to the beach. The data and information derived from this study is now available to inform future shoreline management practice, and crucially, stakeholder engagement – a key goal of the study”.
Partrac scientist Dr Jack Poleykett is presenting the study findings at the upcoming Western Dredging Association Dredging Summit and Expo ’18, and a manuscript is to be published in the conference proceedings. For further details regarding the project, and the tools and techniques employed, contact Dr Kevin Black (firstname.lastname@example.org).