Numerical Modelling of Oil Spill Transport in Tide-Dominated Estuaries: A Case Study of Humber Estuary, UK

Chijioke D Eke,Marco J Van De Wiel,Damian Lawler,Babatunde Anifowose,Michiel A F Knaapen

doi:10.3390/jmse9091034

Chijioke D Eke, Marco J Van De Wiel + Show 3 more

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https://doi.org/10.3390/jmse9091034

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Abstract

Oil spills in estuaries are less studied and less understood than their oceanic counterparts. To address this gap, we present a detailed analysis of estuarine oil spill transport. We develop and analyse a range of simulations for the Humber Estuary, using a coupled hydrodynamic and oil spill model. The models were driven by river discharge at the river boundaries and tidal height data at the offshore boundary. Satisfactory model performance was obtained for both model calibration and validation. Some novel findings were made: (a) there is a statistically significant (p < 0.05) difference in the influence of hydrodynamic conditions (tidal range, stage and river discharge) on oil slick transport; and (b) because of seasonal variation in river discharge, winter slicks released at high water did not exhibit any upstream displacement over repeated tidal cycles, while summer slicks travelled upstream into the estuary over repeated tidal cycles. The implications of these findings for operational oil spill response are: (i) the need to take cognisance of time of oil release within a tidal cycle; and (ii) the need to understand how the interaction of river discharge and tidal range influences oil slick dynamics, as this will aid responders in assessing the likely oil trajectories.

Highlights

Accepted: 10 September 2021Estuaries can be defined as semi-enclosed bodies of water in which incoming saline ocean water is diluted by freshwater [1]
We present the first detailed analysis of oil spill dynamics in a large well-mixed macrotidal estuary with some significant contributions to the field
Using the Humber Estuary as a case study, we assessed the influence of tidal cycles and freshwater discharge variability on the dynamics of hypothetical oil spills

Summary

Introduction

Accepted: 10 September 2021Estuaries can be defined as semi-enclosed bodies of water in which incoming saline ocean water is diluted by freshwater [1]. Most estuaries because of the services they can provide, increasingly host shipping vessels of different sizes [6]. These vessels include crude and refined oil carriers, with potential risks of oil spills during routine processes such as engine maintenance, transfer of contents, and tank cleaning [7]. There is the risk of accidents, such as grounding and collision which can be major sources of oil spills [8,9,10] These raise significant concerns as oil is considered one of the most detrimental sources of anthropogenic pollution in estuaries [11,12]

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