Climate and landuse changes are having significant global impacts on the quantity as well as quality of water resources. Despite a large body of published research on the impacts of climate and landuse changes on water quantity, systematic assessment of the implications for water quality has received much less attention. This PhD project aims to assess the impacts and associated uncertainties of climate and landuse changes on water quality in the upper Huai river basin. It is a semi-humid basin of 31,000 km2 located in central-east China, a very important agricultural region with associated problems of water pollution by agrichemicals.

A multi-model ensemble (MME) approach will be implemented with the aim of enhancing simulation performance through reduction of overall model bias, and assessing the model uncertainties. Because no single model can be regarded as the best model that can perfectly describe one or more hydrological and bio-chemical processes in a basin, MME improves simulation outcome through member models compensating for each other's shortcomings. At least three different water quality models with different model structures and complexities will be selected in this research.

The objective of the PhD project is to quantify regional impacts of climate and landuse changes on water quality using the MME approach. The PhD project is expected to be implemented in the following steps:

• Selection of a catchment within the upper Huai river basin as the study area and collation of existing climate, hydrological, water quality and GIS data;
• Select, set up, calibrate and validate at least three different water quality models with different model structures and complexities;
• Use different MME combination methods and compare model simulation performance with that of each individual model;
• Review current land use management practices and relevant policies, and develop plausible landuse change scenarios;
• Select a suitable weather generator and downscale future regional climate projections;
• Use the best three combination methods to simulate water quality under various landuse change, climate change and combined change scenarios;
• Quantify impacts on water quality and analyse the uncertainties.

This research will evaluate the capabilities of agricultural diffuse pollution load reduction by representative mitigation measures under current and future climate and landuse scenarios and also provide essential scientific evidence to develop both near- and long-term adaptation strategies to improve water quality while sustaining regional economic growth in the upper Huai river basin. The PhD will offer the successful candidate international experience of water resource modelling appropriate to a high-level career in river basin management.

This studentship is open on a UK/EU competition funded basis and also on a self funded basis.

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(iv) Viney, Neil R., H. Bormann, L. Breuer, A. Bronstert, B.F.W. Croke, H. Frede, T. Gräff, L. Hubrechts, J.A. Huisman, A.J. Jakeman, G.W. Kite, J. Lanini, G. Leavesley, D.P. Lettenmaier, G. Lindström, J. Seibert, M. Sivapalan, P. Willems: Assessing the impact of land use change on hydrology by ensemble modelling (LUCHEM) II: Ensemble combinations and predictions, Advances in Water Resources, 32(2), 147–158, doi: http://dx.doi.org/10.1016/j.advwatres.2008.05.006, 2009.