By ECE student Ben Flett (2016-2017)
The ECE students as well as a cohort of Oceanography MSc students have recently begun the intensive short course in Modelling Coastal Processes. Within this course the use of extremely powerful modelling software has been utilised to propose a dredging channel in the Southampton Solent through an area known as Bramble Bank. The models have been run using Pyxis and Telemac software so that predictions can be made and examined if the dredged channel were to go ahead. Within these models, tidal velocities, shear stress and even dispersion of sediments can be examined. In order to validate and calibrate these models extensive field measurements were required.
The ECE MSc enables the students to access to University of Southampton’s research vessels, the RV Bill Conway and the RV Callista, therefore a boat work campaign and plan was designed and implemented so that the models which had been created could be calibrated and validated. This started on Tuesday the 28th of February which 6 students embarking on the first day of surveying on board the RV Bill Conway. The students were tasked with obtaining sediment grabs and deploying sediment traps around the bramble bank area in order to obtain sediment characteristics and mobility data. As well as this the Bill Conway is also fitted with an Acoustic Doppler Current Profiler (ADCP) which allowed large amounts of data on the hydrodynamics of the area around Bramble Bank to be collected, helping to further validate our models.
The second group of 14 students went out on the Thursday the 2nd of March onboard the larger research vessel Callista. The emphasis of this boat work was to collect further data in the harder to reach channels as well as obtain data on sediments and hydrodynamics which had not yet been surveyed. Sediment grabs and ADCP data were deployed regularly as well as a CTD and Nisken samples which allowed the assessment of temperature, salinity, conductivity and the concentration of sediments in the water collumn; all of which helped to validate and calibrate the models being run.
As well as deploying these high tech surveying methods a simpler method was used to test dispersion of particulates in the area. By dropping oranges off the boat and tracking their path as well as dispersion for a set amount of time with the vessel’s GPS we could determine their path and the dispersion in the area.
The data collected was then collated and analysed by the students in order to help validate and calibrate the models. This enabled a better understanding of how the system worked and what processed would affect the proposed dredge channel. The successful boat campaign also gave the students a taste of what some work as a Coastal Engineer could entail all be it with some rather fantastic weather making the second day extremely enjoyable!