Understanding impacts of flooding
in South East Asia


Thai coastal communities prepare for climate change

Our specialist modelling experts are helping Thai coastal communities prepare for climate change

What's the Challenge?

Ambiental is amongst a group of international researchers helping South East Asian countries to develop resilience to hazards such as floods, droughts, storm surges and landslides.

Hydrometeorological hazards pose a direct threat to lives and livelihoods of people living in South East Asia, from death and injury to damaged or destroyed homes, businesses, transport links, power supplies and agricultural land.

Climate change and population growth are increasing the number of people at risk, and changes in land use and the expansion of urban areas has led to a shift in how floods and droughts impact communities.

The Newton Fund, NERC and the Economic & Social Research Council (ESRC) have established joint programmes with five partner countries in South East Asia to improve understanding of the impacts of these hazards in the region. Over three years a total of 18 projects will be supported in partnership with Indonesia, Malaysia, Philippines, Thailand and Vietnam. Ambiental is providing in-depth analysis and expertise to one of these projects, ‘Thai coast: Coastal vulnerability, resilience and adaptation in Thailand’.

In Thailand coastal communities are understanding and preparing for climate change through Ambiental’s work on the project examining not just flood risk, but also changes in sea level, soil composition, farming and other urban considerations and non-physical geography.


Academics from the University of Sussex conducting the project approached Ambiental for its expertise in flood modelling and previous experience carrying out similar analysis to that already executed in the development of FloodFutures. Ambiental were asked to model six different catchments, covering quite a large area of river, island and concentrated coastal communities, up to one tenth of the size of Thailand. The company has been tasked with two important areas of understanding:

  1. Understanding river flows now and how they might change in the future.
  2. Modelling various different flood plain extents for now and again in the future.
Thai Coastal Flooding

FloodMap extents for the 1 in 50yr severity for 2020 (blue) and predicted in 2090 (red)


FloodMap extents for the 1 in 50yr severity for 2020 (blue) and predicted in 2090 (red)

The Solution

The team at Ambiental, under the guidance of David Martin, CTO and José Tenedor, Technical Consultant are working with the University of Brighton and the University of Sussex to deliver the two components of the project. Brighton University has been working with Ambiental on the hydraulic modelling using Flowroute-i™ and the preparation of the data around that. They will be doing GIS analysis on the results, looking at how many properties and how many people might be affected now at different flood frequencies and in the future and how again that may change over time. Sussex University, meanwhile, has been using super-computers to undertake climate modelling which Ambiental has been using to then drive their understanding of the future flows.

For the present day flood modelling, Ambiental need to use standard hydrological techniques to understand river flows, incorporating local knowledge acquired from recent projects in South-East Asia. In parallel, Sussex University have been running high-powered, high-resolution climate models over the catchment areas in Southern Thailand. The climate modelling is simulating future weather systems, of which we were particularly interested in the major rainfall events across the multi-decadal future epoch. Ambiental were working with data from 15 years’ of time (from 2080 to 2095) so approximately 60-70 years’ into the future.

José said: “Given we are interested in the future climate (as opposed to a specific event), we are keen to understand the averages and frequencies associated with that future epoch, so we are not too interested in any single year in isolation. Instead, we look at the whole period of time and say, “let’s imagine the climate model outputs actually represent gauge measurements from the last fifteen years” – and then apply the same frequency modelling techniques as we would do for today. So, whereas now we might be able to measure the rainfall, in the future, of course, we need to simulate it.”


Increase of the Peakflows due to the Climate Change Factor (CCF) for several Return Periods

The Outcome

David said: “It’s a little tricky, and some assumptions have obviously had to be made, however the project has gone very well. The future model has been simulated and there will be an update to it in the months to come. The model is actually very similar to our FloodFutures product in the UK, where we provide the extent of flooding now, and through various future epochs and emissions scenarios. You can look at the output statistically, or compare visually using GIS – down to the individual building level.”

What's next?

José has developed a method for adjusting up or down the peak river flows depending on how the future rainfall frequencies compared to now. What we will do next is essentially migrate this to other regions of interest around the world.

José commented: “It has been challenging to determine the best local methodology for how we should compare the current and future flows. The model we have developed up with is consistent and robust, and is the foundation for us to further develop our modelling techniques on another similar project in future.”

Ambiental will continue to support this project for the duration of its term of three years.



FloodFutures is our predictive flood model that considers nine possible climate change scenarios between 2020 and 2080.

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