London and the South-East is the economic 'powerhouse' of England contributing 40% of GDP. Currently there is a shortage of housing, particularly affordable homes, and 50,000 new homes per year are planned for London to 2036. The growing population of London and its planned housing require water to be supplied and flooding to be reduced as far as possible. However, the region is vulnerable to water shortages (droughts) and floods. In the spring of 2012 London was facing potentially its worst drought, with concerns whether Affinity Water could provide sufficient water for some Olympic events. By contrast, the prolonged rainfall that then fell over the summer caused localised flooding and the Thames barrier being closed twice. This swing, over half a year, from extreme shortage of water to excess highlights the major challenge London faces to manage the water environment. This challenge is likely to worsen with climate change alongside the expected economic growth of London and associated increase in population. It also shows how droughts and flooding are two ends of a hydrological spectrum, whose political oversight, i.e. governance, needs to be managed was a whole. It is this need for integrated, collaborative and appropriate management that lies at the heart of CAMELLIA. Focusing on London, CAMELLIA will bring together environmental, engineering, urban planning and socio-economic experts with governmental and planning authorities, industry, developers and citizens to provide solutions that will enable required housing growth in London whilst sustainably managing water and environment in the city. CAMELLIA will be led by Imperial College London, working in collaboration with researchers at University College London, the University of Oxford, and the British Geological Survey. The programme is supported by communities, policymakers and industry including: local and national government, environmental regulators, water companies, housing associations and developers, environmental charities and trusts. Ultimately, the programme aims to transform collaborative water management to support the provision of lower cost and better performing water infrastructure in the context of significant housing development, whilst improving people's local environments and their quality of life. The relationships between the natural environment and urban water infrastructure are highly complex, comprised of ecological, hydrological, economic, technical, political and social elements. It is vital that policy and management are informed by the latest scientific understanding of hydrological and ecological systems. However, for this knowledge to make a change and have an impact, it needs to be positioned within wider socio-technical and economic systems. CAMELLIA will provide a systems framework to translate Natural Environmental Research Council-funded science into decision-making. Enabling a range of organisations and people to contribute to, and apply systems-thinking and co-designed tools to create a paradigm shift in integrated water management and governance underpins CAMELLIA. This will achieve the goal of real stakeholder engagement in water management decisions and provide a template, not just for London's growth, but for other cities, regions and communities both nationally and globally. The proposed work programme consists of four work packages which address 4 key questions, namely: How to understand the system?; How to model the integrated system?; How to analyse that system?; How to apply this systems approach to create impact? To help focus these questions, four London based case studies are being used, each reflecting a key issue: Southwark (urban renewal); Thamesmead (housing development); Mogden (water infrastructure regeneration); Enfield (Flood risk and water quality). From these, an integrated systems model will be applied to the entire city in order to help guide policy, planning and water management decisions.