Possible PhD Projects (closed)

I currently have a number of possible PhD research projects that could be funded either under the Durham Doctoral Studentship or NERC studentship. The deadline for applications for funding is the 18th Feb 2013. The application details are at: http://www.dur.ac.uk/geography/postgraduate/

Rapid assessment of water quality pressures on water bodies using new tools and techniques

Supervised by Dr Sim Reaney

Currently in 2012, only 28% of the water bodies in England are meeting their WFD target of good ecological status and of those sites that are falling, 67% cite diffuse pollution of nutrients and fine sediment as an important pressure. The complexities of the diffuse pollution problem, the large number of individual sites, the large number of different mitigation options and social and economic implications of the mitigation works mean that it is difficult to develop a robust mitigation plan for a site. There is therefore a need for a decision support tools which will enable the selection and location of mitigation measures within the landscape in a consistent and effective manor based on local environmental evidence. This PhD project will investigate how to rapidly assess the key pressures on a site using a combination of historic data, new high temporal frequency water chemistry data, targeted field measurements and GIS tools, such as SCIMAP. This site characterisation will then be used to inform the development of mitigation plans for the catchment to relive the water quality pressures on the site. This project will be undertaken in collaboration with Natural England.

Temporal patterns of diffuse pollution risk: Monitoring with UAV and modelling approaches
Supervised by Dr Sim Reaney & Professor Tim Burt

The impact of diffuse pollution on water bodies is significant and is cited as a key reason why many rivers and lakes are not meeting the Good Ecological Status level under the Water Framework Directive. Due to the extensive, temporally and spatially variable nature of diffuse pollution, it is difficult to monitor, map or mitigate. A useful framework for understanding diffuse pollution is ‘Source-Mobilisation-Pathway-Impact’ and the spatial configuration of the sources and pathways will lead to the creation of Critical Source Areas. Through understanding how the source and mobilisation risks change in space and time allows for greater targeting of mitigation measures within the catchment and hence the greatest reduction in diffuse pollution risk.

Most approaches to mapping diffuse pollution risk are based on a fixed land cover map to describe the spatial pattern of source and mobilisation risk within a catchment. However, the land cover varies on both annual cycles and sub-annual time scales. Between years, different crops are planted in the same field as part of a crop rotation and during the year, the amount of bare ground changes as the crops grow, hence changing the diffuse pollution risk. The aim of this PhD project would be to explore how information on the annual and sub-annual vegetation cover can be captured and utilised within a diffuse pollution risk mapping approach. Methods that will be explored include simulation modelling of crop growth, low level remote sensing using a quadcopter UAV and fixed location high resolution time-lapse photography. The spatial pattern of risk will then be used within the SCIMAP risk mapping framework to identify key mitigation locations within the catchment. The project will be set within the River Eden catchment in collaboration with the Defra funded River Eden Demonstration Test Catchment project.

Maximising information gain from catchment monitoring and modelling: An integrated, iterative solution
Supervised by Dr Sim Reaney & Dr Jeff Warburton

When trying to understand how complex linkages in natural environment work, the problem is often approached from either an environmental monitoring or simulation modelling perspective. Each of these methods takes a different approach and has different strengths and weaknesses. In environmental monitoring, the critical issue is to determine what, when and where to monitor for the maximum information gain about a system? With simulation modelling, there are important problems centred on predictive uncertainty and the need for data with higher information content than is currently available.

The aim of this PhD project will be to address these two problems through applying an integrated iterative method of monitoring and modelling. The initial model predictions will be used to design the monitoring scheme and the measurements will be used to assess the model performance. The spatial predictive uncertainty of the model will then be used to find the spatial locations with the greatest information content and the monitoring network adjusted to measure in these locations. The value of multiple low cost but low precision sensors as opposed to a limited number of high quality sensors will be assessed. For example, is fine fluvial sediment flux best estimated from a single high-resolution monitoring station, a network of low cost sensors or using a network of low cost mechanical time integrated massflux sediment traps?

The research work will focus on both diffuse (non-point source) pollution within the SCIMAP Framework and catchment hydrological processes within the fully distributed CRUM3 model. Field work will be based within field sites in northern England.

Representing connection in hydrological landscapes (PhD)

Supervised by Dr Louise Bracken & Dr Sim Reaney

Recent years have seen a renewed emphasis upon the importance of hydrological connectivity in landscapes over a wide variety of spatial and temporal scales (e.g. Bracken and Croke, 2007). It has also been subject to mathematical representation, using approaches that vary in sophistication from simple distance weighting through to full evaluation of the effects of topographic structure upon patterns of wetness and hence connectivity (e.g. Lane et al., 2010; http://www.scimap.org.uk/). Thus far, such treatments of hydrological connection have only really begun to capture the range of controls upon the connection process, despite its integral role in the transfer of fine sediment and nutrients from hillslopes to the drainage network. Durham University, with partners at the University of Lancaster, the Environment Agency and the Association of Rivers Trusts, has been pioneering research into hydrological connection using both innovative field instrumentation and mathematical modeling. The latter has included using physically-based distributed hydrological models to explore the information content of simpler determinants of connection. In relation to the latter, there are two particular areas that warrant attention: (1) soil form and function; and (2) controls on connection associated with human artefacts, such as drains and roads. This proposal brings together two Durham scientists to work on these areas to improve representation of connection in hydrological landscapes.

The work will be based upon:

1. parameterisation, including uncertainty estimation, of physically-based distributed models of number of representative agricultural catchments;
2. the use of these catchments to determine the time-dependent and spatial characteristics of hydrological connection for benchmark comparison against simpler treatments;
3. the development of means of combining soil processes into the representation of hydrological connectivity;
4. the development of means of identifying human artefactual controls upon connection and their representation in models of hydrological connectivity; and evaluation of (3) and (4) with respect to (2).

This PhD will be suited to a student who is interested in fieldwork and mathematical representation of an important hydrological phenomenon. No prior modeling experience is required, but applicants must be numerate.