Sun Yan Evans: spearheading the assessment of flood risks

Sun Yan’s career began in China in the early 1980s with research into water quality, which remains central to the country’s national standards today. Since then, she has worked across the world on some of the most forward-thinking projects involving water quality, flood resilience and water modelling.

This is her story.

Sun Yan is a Fellow of the Institution of Civil Engineers (ICE) and a member of the Chartered Institution of Water & Environmental Management. She’s also a member of the Department for Environment, Food and Rural Affairs (Defra), Environment Agency, and Natural Resources Wales research and development advisory group, informing UK government policy, strategy and standards.

“Everywhere, life needs water,” Sun Yan says. “Water is an incredible resource, but too much, too little, or poor quality water can be damaging.”

In Chad and Cameroon, Sun Yan helped develop better understanding in improving biodiversity along the Waza Lagone river system and its floodplain, a project that called for a large-scale hydraulic model along more than 300km of the river.

In the UK, Sun Yan was the driving force behind a flood resilience programme designed to safeguard more than 100 sites for leading energy company National Grid; the Boston Barrier flood defence system, a £100M project that protects more than 14,000 homes; and the Humber Hull Frontage flood defence improvements, which reduces flood risk for 113,000 properties.

Sun Yan has been called on as an expert witness in public inquiries and court cases. She’s a prolific author, with several books, contributions to the Institution of Civil Engineers’ State of the Nation reports and more than 30 papers to her name. She has received more than 20 industry awards in the past two decades.

Among Sun Yan’s landmark achievements, she developed a methodology to assess flood risk and the potential impact of overtopping for reservoirs. Her work addressed the urgent need to assess more than 2000 reservoirs when available funding would have allowed for assessment of only 100 using conventional methods. Throughout the 1980s, Sun Yan pioneered the use of computer modelling to address engineering challenges more efficiently. In this instance, her use of data, automation and interpolation, linked with a graphic user interface to aid communication, enabled all the reservoirs to be assessed within the available budget. Her system has been continually refined and is used by the Environment Agency nationally.

“Engineering is, in many senses, about turning the seemingly impossible into the possible,” she says.

Sun Yan led the development of similar smart solutions for assessing the risk and impacts of coastal and river flood defences being overtopped, with the insights informing disaster response planning, public communication and investment in defence strengthening.

“Not only does Sun Yan strive for the highest levels of technical excellence, she’s working hard to pass that knowledge on to the next generation,” says James Harris, chair of Mott MacDonald’s executive board. “That’s leadership at its best.”

This is evident through her passion for education outreach initiatives designed to help young people see the value in a career in engineering.

“Water engineering touches so many areas of life – our health, food production, flood protection and diverse ecosystems, and it interacts with transport, buildings and energy systems. As a water engineer you can travel the world, meet great people and do a lot of problem solving. It’s an enormously fulfilling career. I just love it.”

Join trailblazers like Sun Yan by exploring opportunities within our water teams, here.