Mitigating Road Infrastructure Flooding in Vietnam
Analytics based on mathematics can solve important real world problems. Applied mathematical modelling belongs to a discipline called Operational Research which was developed in Britain at the time of the First World War when planning based on systematic analysis was enlisted in the war effort. Few real world problems are more important than the impact of climate change on people’s lives, especially in those places on the climate change front line. Vietnam — with its long coastline, increasing rainfall and danger of flooding — is one of these hotspots.
A British Academy-funded research project, led by Professor Maria Paola Scaparra[i] at the University of Kent and her collaborators in Hanoi, has developed an app that models the most efficient use of available resources in minimising the impact of flooding on the lives of local people. The intensity and frequency of flooding in cities across Vietnam has increased in recent years. Flooding brings heightened risk of water pollution and a range of health hazards as well as collapsed roads and buildings that are disruptive of people’s lives. Those most effected are the poorest and most marginal communities which are already struggling to survive.
In tune with bottom-up approaches across the British Academy’s Cities and Infrastructure Programme of which this project is a part, the research team began by surveying local people, many of them street traders and shopkeepers living in popular neighbourhoods, to discover which aspects of flood damage were the most difficult to manage and disruptive to their everyday lives.
Perhaps surprisingly it was not water damage to their own homes that most concerned people, but the traffic congestion and circulation difficulties caused by road flooding. Women in particular found it difficult to pursue their responsibilities for working, trading and taking care of family well-being, including getting children to school when roads were flooded. The survival of these marginal populations, it seems depends on their ability to circulate around the city piecing together viable lives. The priorities of the poor are not always built into models. Road flooding points to the importance of drainage and pumping stations, and the project team discovered that local people wanted the government to work with them in improving drainage and pumping away floodwater.
Researchers at the Institute of Geophysics of the Vietnam Academy of Science and Technology (VAST) produced high-resolution rainfall projections for the city of Hanoi. These were then used by the Vietnam Institute of Meteorology, Hydrology and Environment (IMHEN) to create flood maps of the city for different future climate change scenarios. These maps were fed into the app, along with a list of drainage mitigation strategies extracted from the Hanoi City Drainage Master Plan. The Master Plan includes a range of different measures to deal with flooding and drainage, such as repairing lakes, reservoirs and other kinds of excess water capture, together with their associated costs. Maps of traffic flows in the city provided by the Ministry of Transport were fed in too. The app calculates which strategies should be prioritised in order to reduce the impact of future floods in the most vulnerable neighbourhoods. It works as a decision-making tool for city authorities to decide when and where to install flood prevention measures given limited resources.
The research is small in scale and most of the findings apply to the city of Hanoi only. It is nonetheless important as flood damage impacts on the well-being and livelihoods of the city’s poorest and most precarious communities disproportionately. Mitigating flooding with appropriately placed drainage systems will immeasurably improve everyday life.
Meanwhile, people have taken their own precautions too. As we wander some of Hanoi’s narrow alleyways speaking to traders and motorcycle taxi drivers, we come across houses where families have built ad hoc metal barriers across their front doors to prevent floodwater entering their houses. One resident had also installed an under-floor drainage system and pump in his living room. Ingenious improvisation. But stronger measures are also needed and the app provides a systematic steer in planning solutions. It helps the authorities decide where to site manholes and pumps, and which measures, including improvement to the capacity of reservoirs and lakes, best and most cost-effectively reduce damage to roads and traffic congestion.
Despite being based on a case study of Hanoi, the results of this research travel beyond their place of data collection and application. Professor Scaparra is writing a manual which will allow the app to be adapted and used in other places and other scenarios as a climate mitigation-planning tool, at the same time building local authorities’ capacities in flood mitigation. Most importantly, three strategic agencies in flood mitigation — IMHEN, VAST and the Transport Development and Strategy Institute (TDSI) — brought together by the excitement generated by the research project — are collaborating for the first time. Legacies like these are important if research findings are to have lasting value in changing the ways in which local people live with the risks of climate change.
The TDSI, the Vietnam Ministry of Transport’s strategy unit, is taking a lead with municipal authorities in suggesting that the app be used to plan for future flooding and drainage in Hanoi. It also has bigger plans. It wants to develop the app to deal with the pressing issue of flooding in the Mekong Delta, and has convinced the Vietnamese Government to apply for a loan from the World Bank in order to expand this research to the Delta.
The Mekong Delta is in danger of flooding not just from increased rainwater as in Hanoi, but also from rising sea levels associated with global warming. This is Vietnam’s most economically important and populous region — with an official population that exceeds 20 million — containing a number of large and important cities including Ho Chi Minh. The country’s rice, fruit and vegetables are grown there. The Delta is also a most important centre for fishing and fish-farming, and its exports significantly support the Vietnamese economy. As Vietnam provides affordable rice to a number of African nations, the impact of salinisation in the Delta is potentially catastrophic for local and international food supplies to the world’s poorest people.
Caroline Knowles is Professor of Sociology at Goldsmiths University of London and Director of the British Academy’s Cities & Infrastructure Programme. Caroline writes about migration and circulation of material objects — some of the social forces constituting globalisation. She is particularly interested in cities, having done research in London, Hong Kong, Beijing, Fuzhou, Addis Ababa, Kuwait City and Seoul.
[i] Optimal Investment Strategies to Minimise Flood Impact on Road Infrastructure Systems in Vietnam (GCRF-OSIRIS). Dang Thu Phuong is the UN consultant working on the project, liaising with agencies in Vietnam, and Siao-Leu Phouratsamay is a Postdoctoral Assistant contributing to the research. Dr Pham Hoai Chung at TDSI is an important project collaborator and partner. Ngô Công Chính, Director of the Asian Management and Development Institute, coordinates the Vietnamese research teams. GCRF-OSIRIS is one of seventeen projects comprising the British Academy’s Cities and Infrastructure Programme.