Over the past 50 years changes in UK land-use have been considerable and substantial change is likely to continue. The UK population is projected to increase by 16% to 2035 which will bring about change to the size and structure of urban areas and increased pressure on land management, especially in the south-east. This project, by calling upon a range of tested modelling approaches and associated expertise will advance understanding of the fine-scale impacts of urbanisation on water resources and pollution, which are currently poorly understood. The focus will be on water security in the Thames river basin where projections of future population and climate indicate serious water stress. Detailed case studies at a local scale (including Bracknell and Swindon), where the impacts of past land-use changes on river hydrological and ecological regimes are likely to be large, will be undertaken and a novel integrated modelling approach developed and tested. The approach will then be rationalised and up-scaled for testing across the entire Thames, and, in conjunction with projections of urban development and land management change, used to quantify future effects. These findings will be set in the context of effects indicated to be a direct consequence of climate drivers.