PhD: Climate change impacts on saline-fresh water interactions in coastal areas

Project Description

Coastal zones are hydrologically and hydrogeologically very dynamic systems. Steep salinity gradients develop where rivers flowing towards the sea meet seawater in creek systems and hydraulic gradients vary strongly over tidal cycles. Simultaneously, fresh and saline groundwater interact in coastal areas, both by exchanges through riverbeds and on a larger scale by groundwater movement controlled by water table and tidal dynamics. As a result of these hydrological dynamics characteristically zoned ecosystems develop. These ecologically sensitive systems are likely to be impacted by climatic changes that alter the hydro(geo)logical regime of coastal zones such as changes in sea-level and coastline position, tidal dynamics, and meteorological conditions. This research project seeks to use field observation and numerical modelling to improve our understanding of how, and on what time-scale, the dynamics of coastal hydro(geo)logical systems are likely to change in response to such processes.

Field data need to be collected to characterise, in and below tidal creeks, the interaction of sea water with fresh river water as well as with groundwater through stream bed exchange. For this, fieldwork is planned to be carried out along the north Norfolk coast. During preliminary investigations, temperature has been shown to be a tracer for sea-water which often has a distinctly different temperature from that of river water and groundwater. This will allow for the deployment of Distributed Temperature Sensing (DTS) techniques in order to obtain records of the spatial-temporal dynamics of saline-fresh water interactions in streams in great detail. Such data will be complemented with geophysical surveys and point observations of salinity and temperature in river- and groundwater. The data will be tested against predictions from numerical modelling studies which subsequently will be used to evaluate scenarios of future climate changes.

 

References

i) Knighton, A. D., Mills, K. and Woodroffe, C.D., Tidal-creek extension and saltwater intrusion in northern Australia, doi: 10.1130/0091-7613(1991)​, v. 19 no. 8, p. 831-834

ii) Bense, V.F., and H. Kooi (uner review), Aquitard control on salinization rates of offshore aquifer systems after sea-level rise, Geophysical Research Letters

iii) Bense, V.F. and H. Kooi (2004), Temporal and spatial variations of shallow subsurface temperature as a record of lateral variations in groundwater flow, Journal of Geophysical Research, 109, B04103, doi:10.1029/2003JB002782

 

Start date: October 2015

Programme: PhD

Mode of Study: Full Time

 

How to Apply

Deadline: 31 May 2015. NB Applications are processed as soon as they are received, so early application is encouraged as the project may be filled before the application deadline.

 

More information and apply online.