The Poyang Lake dilemma
Jonathan Hin Chung Ho (Croucher Scholarship 2015) is a PhD student at Christ’s College, the University of Cambridge. His research topic is the “simulation of pollutant transports in Poyang Lake, China”, under the supervision of Dr Dongfang Liang.
Covering a vast expanse of 4,400 square kilometres in northern Jiangxi Province, Poyang Lake is the largest freshwater lake in China. Connected to the Yangtze river, it is surrounded by a population of 12 million people, boasts the largest concentration of migratory wintering waterbirds in East Asia, and is home to a number of rare animal species, including the only freshwater porpoise in the world.
The lake experiences naturally high water level fluctuations. In a normal year it averages 3,500 square kilometres. During summer months water levels are high, but in winter it looks more like a river than a lake. Since the Three Gorges Dam went into operation in 2003, the lake’s fluctuations have markedly intensified. This has resulted in seriously depleted water levels and worrying repercussions on the lake’s ecosystem. In early 2012, the lake shrank to a record low of just 200 square kilometres.
In 2008, the Chinese government proposed the Poyang Lake Dam (also known as the Poyang Lake Water Conservancy Project) to address these extreme fluctuations. Due to a number of setbacks, including the technical challenges of the lake’s fluctuating water levels and scrutiny from environmentalists, the project has since been postponed - pending further research.
Although in the relatively early stages of his research, Jonathan has a clear idea of what he expects to achieve by the end of his PhD, and the wide-reaching future applications of his research. He breaks down the next few years into two stages:
The first stage will involve modelling using a numerical model based on total variation diminishing and the MacCormack method. Total variation diminishing is a property of certain discretisation schemes used to solve hyperbolic partial differential equations. The MacCormack method is a widely used discretisation scheme for the numerical solution of hyperbolic partial differential equations. These methods will solve the depth-integrated solute transport equation - in short: how water flows around the lake.
The second stage of Jonathan’s research will focus on the movement and distribution of specific pollutants within Poyang Lake. Pollutants are especially dangerous to the lake’s ecosystem during low water levels in winter. Jonathan’s research will involve in tracking (or modelling) indicators such as biochemical oxygen demand, chemical oxygen demand, nitrogen, phosphorus, heavy metals and other physical parameters such as temperature and salinity. This will enable him to measure the effects that pollutants have on the ecology and environment of the lake and will enable scientists to plan the optimal positioning of certain infrastructures and water management systems, such as the stalled Poyang Lake Dam.
Although Jonathan’s PhD research is directly applicable to Poyang Lake, the technology and skills may later be applied across the world in places such as the Netherlands, Norway, and other parts of China, as well as other developing and emerging countries. Some of the dimensions it will be applicable to include master planning, environmental conservations, freshwater resources management and supply, and the impact of infrastructure on water environments. Jonathan expects to complete his PhD in late 2017.
Jonathan completed his MEng (2012) in civil engineering at Imperial College, London. He then undertook an MPhil (2013) in engineering for sustainable development at Clare Hall, the University of Cambridge. The topics he covered were sustainability methods and metrics; sustainable design and implementation concepts, values and change processes; economics, legal and regulation issues; sustainable water engineering and environmental engineering; electricity and the environment, and management of technology.
To view Jonathan’s personal Croucher profile, please click here.