Flooding is a threat to communities in both Malaysia and the UK. Computer modelling is a widely used approach to working out which areas are vulnerable to flooding. This allows government agencies, NGOs and communities to work out how to invest time and resources to protect areas at risk. Understanding of the causes of flooding has increased rapidly in recent years. We now have good data on environmental factors like rain and temperature which can influence where floods will happen. There are now good models of climate change. If we work out where flooding is going to happen, computer models can now be used to work out how flood waters will move around cities and which buildings will flood. One problem that still remains is to include the complexities of real life in these models. We currently assume that the same flood will always lead to the same consequences. This makes models quicker to run, but we know it's not how flooding works. If floods occur just before harvests they can destroy entire crops, but if they occur when fields are empty the costs can be very low. If one flood follows another in quick succession, facilities like hospitals and power stations could remain damaged from the first flood, meaning that the second one has much greater impact on people's lives. With research into how communities are affected by flooding, which takes into account the timing of floods as well as how closely associated they are in time, a genuinely new approach to flood risk could be developed. Malaysia is a very good place to develop these models. Its economy is developing quickly, so new approaches have the opportunity to be tested in a changing environment. Similarly, climate in Malaysia includes monsoons, which are a good test of model ability for environmental modellers. From a development perspective, Malaysia is a success story which is rapidly transitioning towards developed status, but still has large numbers of people at risk and in large areas, development can be set back by severe floods. Lastly, following severe floods in 2014, there is a renewed interest in developing innovative flood risk approaches in Malaysia. Our approach to developing a new flood model in Malaysia would make use of the different experts in our group. Bringing together experts from the UK and Malaysia, both of which have invested significantly in flood research in the last decade, would allow us to combine skills from experts with different specialities. Our economists will use economic modelling to understand how different sectors of the economy might change in future and how they might be exposed to flooding. Our group's environmental scientists will use existing computer models of rivers to show where river levels are likely to become high enough to generate flooding. Our flooding engineers will apply new hydraulics models to show how flood waters move once they have left the rivers. Experts in combining computer model outputs will combine each of these into a new model of flood risks. This new model will be used to find the effects of scenarios (factors we can't control such as climate change and increasing urbanisation) and strategies (factors we can control such as new flood defences and warning systems) which will help to evaluate some of these strategies for their effectiveness and value for money. This will allow future flood planning to be better targeted within Malaysia. We hope that Malaysia will act as a good case study for this research and that it would be taken up by other countries in South East Asia and around the world.

A reliable and acceptable quantity and quality of water, and managing water-related risks for all is considered by the United Nations to be "the critical determinant of success in achieving most other Sustainable Development Goals (SDGs)". Water is essential for human life, but also necessary for food and energy security, health and well-being, and prosperous economies. However, some 80% of the world's population live in areas with threats to water security; the impacts of which cost $500bn a year. Progress in meeting SDG6 (Ensure availability and sustainable management of water and sanitation for all), has been slow and in May 2018 the United Nations reported that "The world is not on track to achieve SDG6". Improvements that increase access to water or sanitation are undone by pollution, extreme weather, urbanization, over-abstraction of groundwater, land degradation etc. This is caused by significant barriers that include: (1) Insufficient data to understand social, cultural, environmental, hydrological processes; (2) Existing service delivery / business models are not fit for purpose - costs are too high, and poor understanding of local priorities leads to inappropriate investments; (3) Water governance is fragmented and communities are engage with, and take responsibility for, water security; (4) Pathways to water security are not adaptable and appropriate to local context and values. These barriers are inherently systemic, and will require a significant international and interdisciplinary endeavour. The GCRF Water Security and Sustainable Development Hub brings together leading researchers from Colombia, Ethiopia, India, Malaysia and the UK. Each international partner will host a Water Collaboratory (collaboration laboratories) which will provide a participatory process, open to all stakeholders, to jointly question, discuss, and construct new ideas to resolve water security issues. Through developing and demonstrating a systems and capacity building approach to better understand water systems; value all aspects of water; and strengthen water governance we will unlock systemic barriers to achieving water security in practice.