Investigation of deep sea shelf sandbank dynamics driven by highly energetic tidal flows

- Sand coverage in Inner Sound channel (PF) is described via interrogation of numerous data sources available in this area.
- An overview of the complex 3D tidal flow regime in the Inner Sound channel (PF) is presented.
- The morphodynamic environment of the Inner Sound channel (PF) is modelled in detail.
- Sediment transport mechanisms associated with morphodynamics of deep sea shelf sandbanks are revealed.

In this paper we describe a numerical modelling study carried out to investigate the prevailing sediment dynamics of two large sandbanks located at a site designated for future development of tidal stream energy extraction, in the Inner Sound Channel of Pentland Firth, Scotland, UK. A calibrated and validated 3D Delft3D hydrodynamic model covering Pentland Firth channel was combined with a morphodynamic model. The sea bed changes occurring around the sandbanks during a period of two spring-neap tidal cycles are described and discussed in detail. It was found that both sandbanks, which are located in a deep shelf region (depths > 18 m), are morphodynamically active and their existence and integrity are strongly linked with the existing hydrodynamic regime.