Sri Lanka, like many other developing countries in South Asia, experiences severe heatwaves that affect the health and livelihoods of hundreds of thousands of residents. The risk to heat exposure will be further exacerbated when 1) the heatwave coincides with urban heat island in the urban area in a non-linear manner; 2) there exists a 'cascading/concurrent' heat hazard indoors as the majority of the households in Sri Lanka have no access to air conditioning and people spend the majority of their time indoors. Living in such hot-humid climate for many generations, Sri Lankan people have established the unique and remarkable climatic, historical, cultural and architectural values and knowledge to be resilient to the extreme climate, reflected in the unique vernacular architectural and urban design. However, with rapid urbanization and economic development, the traditional Sri Lankan vernacular villages and dwellings are being replaced by fast-built, western-style brick-concrete structures. The indigenous Sri Lankan climate-sensitive design knowledge is being forgotten and disappearing. In the developed countries, it has been proved that new data streams, improved forecasts and better visualization techniques have the potential to improve the utility of predictions for early warning of adverse conditions. However, for the countries in the global south (e.g. Sri Lanka), it is vital to provide such climate services with embedded indigenous design knowledge and use of local resources to improve the resilience to extreme humanitarian disaster. COSMA is a multidisciplinary study that will bring together a group of experts in urban meteorology, building environmental engineering, architecture, urban planning and social science, to work with local stakeholders to deliver SHEAR programme objectives. At the heart of the project are the studies of: 1) how the heatwave overheating risk prediction and assessment could be improved at finer urban and building scales; 2) what are the useful indigenous design knowledge in Sri Lanka to mitigate heatwaves, and how they could be regenerated and re-incorporated into the heatwave action plan and future design practice? COSMA aims to develop an integrated modeling approach by taking into account the urban heat island, building characteristics and vulnerable population to build effective early warning system and city-scale heat action plan. By closely working with local community, government and professionals, one important goal of COSMA project is to harvest and regenerate traditional design knowledge (both building and urban scales) from indigenous craftsmen embedded within local culture and traditions, and feed into the heat-exposure risk mitigation plan. The final outputs of the project will be a series of hierarchical overheating risk and mitigation potential maps across different scales for Colombo, Sri Lanka. COSMA, led by the University of Reading (UoR), involves collaborations with Glasgow Caledonian University (GCU), and carried out in partnership with a group of well-established Sri Lankan partners-Department of Meteorology (DoM) and the Institute of Town Planners Sri Lanka(ITPSL) as well as researchers at University of Moratuwa (UoM).

Coastal communities in the north and east of Sri Lanka (SL) face significantly greater risk of coastal flooding from storm surges associated with seasonal cyclones than those in the rest of the country. These storm surges are essentially local elevations in sea level caused by the weather system which subsequently inundate the land. Storm surges are caused by a combination of: (1) low atmospheric pressure 'lifting' the sea surface (barometric tide) (2) frictional drag of the wind blowing over the sea causing a slope in the water surface (wind stress) and (3) breaking waves transferring their momentum into the water column (wave setup). Hazard maps, to indicate predicted storm surge inundations around the Sri Lankan coastline, were produced by Prof Wijetunge in association with the Disaster Management Centre. The computer models on which these hazard maps were based, were limited to describing only the barometric tide and the wind stress. Subsequent advancements in understanding mean that wave setup can now be included. It is critical to do so, because the wave setup effect may contribute 40% of the surge in some locations i.e. some communities may face a more grave risk than hitherto realised. The situation is potentially much worse than this however, as scientists are beginning to understand the interaction of storm surges with severe rainfall events which almost always accompany the cyclones in the Indian Ocean region. The mechanism for this so-called compound flooding is that rivers swollen from heavy rainfall are prevented from effectively discharging to the sea due to storm surges coming inland. To protect against flooding events in the west we are familiar with flood defence structures; Sri Lanka has no such hard-engineered structures. However, they do have natural protective features such as mangrove forests and salt marshes. The potential benefits of mangroves in particular have received some attention since the devastating Boxing Day tsunami of 2004, though the intentional implementation in formal coastal schemes is still in its infancy. Prof Taylor recently received funding from the Global Challenge Research Fund to investigate how design codes might incorporate their effects. Against this backdrop, the C-FLOOD project will produce a new generation of compound flood hazard maps, based upon state-of-the-art computer modelling that will consider all the storm surge components and the rainfall effect. It will also consider a variety of climate change scenarios which will influence flooding due to predicted rising sea levels. This will be done by Prof Wijetunge at the University of Peradeniya in SL, and Dr Jayaratne at the University of East London, with their related expertise. Furthermore, the protective effects of the natural vegetation will be included in the modelling and maps, by conducting experiments at the University of Plymouth's COAST Laboratory. This will be undertaken by Dr Raby (Plymouth) and Prof. Taylor (University of Western Australia). The C-FLOOD project will focus on three communities that are deemed most vulnerable due to their geography and levels of poverty (associated with the past military conflict). The project team will work with community members in addition to local and regional leaders/administrators to maximise the benefits and uptake of the new hazard maps. Individual localised hazards will also be captured in comprehensive multi-hazard maps for the communities. Dr Kitagawa from the University of East London and Mr Ranawaka of the Coast Conservation & Coastal Resource Management Department have past experience of such activities and will be overseeing these critical aspects. The final outcome will be improved predictions of flooding inundation, with engagement of the selected communities, leading to improved resilience to compound flooding. The hazard map production techniques and flood impact mitigation methods could then be implemented across other vulnerable communities.