Assessing dynamic seabed change on the UK continental shelf

Lead Research Organisation: University of the Highlands and Islands
Department Name: Scottish Assoc for Marine Science UHI

Abstract

Understanding the rate and extent of change on a dynamic seafloor is an essential requirement for the offshore construction industry. During the lifetime of any structure placed on the seafloor sediment movement can lead to either burial or scouring that will necessitate an additional engineering solution to ensure the structure's long term integrity. The continental shelf contains sediment in both mobile and static condition. Many recognised mobile bedforms on the shelf could be relict, forming during the isostatic readjustment of the shelf after the last glaciation and present no risk. Conversely the rate of transport of modern, active dunes is difficult to ascertain without costly repeated surveys. The recent availability of publicly accessible, regionally extensive, high-resolution seabed mapping data (e.g. multibeam sonar surveys) from the UK Data Archive Centres provides an opportunity to assess the state of sediment stability across a number of different geographical situations.. The project will adopt a case study approach of sites which might present a risk to the offshore construction industry and will include mobile bedforms (dunes), biogenic reefs (cold water corals) and wrecks. Where data sets have been collected over different time periods rates of change will be calculated in order to estimate the scale, rate and extent of change. Pilot studies exist such as Games & Gordon (2015) Study of sand wave migration over five years as observed in two windfarm development areas, and the implications for building on moving substrates in the North Sea. Earth and Environmental Science Transactions of the Royal Society of Edinburgh, doi:10.1017/S1755691015000110.However no comprehensive broad-scale mapping study has been attempted to quantify the rate and extent of seafloor change on the UK continental shelf. The proposal was first developed by Peter Watson at SSE and numerous cable-route datasets exist which would be extremely valuable to compare to previous national seabed mapping campaigns. The project aims to deliver mapping outputs, a number of seafloor 'change' maps in key regions (mobile bedforms, biogenic reefs, wrecks). Predicted change maps quantifying rate of change at a defined timescale. Thesis, scientific publications as appropriate. Close working with stakeholders (SNH, MSS, SSEN) to develop mitigation plans.

Publications

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