School of Geography



Tianyang Du graduated with a First Class Honours degree in Environmental Sciences at the University of Nottingham in 2017, followed by a MSc degree in Hydrology and Water Resources Management at Imperial College London in 2018. He is now a third year PhD student based in the School of Geography co-supervised by Dr. Matthew Johnson and Dr. Stephen Dugdale.

Research Summary

Research Title: Thermal pollution in rivers due to cooling water from power plants and implications for system resilience to future change

Research Supervisors: Dr. Matthew Johnson (School of Geography), Dr. Stephen Dugdale (School of Geography)

Anthropogenic climate change is an important driver of thermal regimes over large scales, primarily via warming. The Earth's atmosphere has warmed greatly since the 1950s, mostly due to increased concentrations of carbon dioxide (CO2) and other greenhouse gases, and is expected to warm further as concentrations continue to rise. It has been estimated that the increase in freshwater temperature associated with climate change is 0.1-0.2 °C per decade (IPBES, 2017). Increases in water temperature will be exacerbated by thermal effluent from power plants. As a particularly significant source of thermal pollution, power plants discharge warmer effluent from their cooling systems, potentially leading to abrupt changes in water temperature and imposing thermal stress on aquatic organisms. Due to their rapid and continued expansion globally, the thermal impacts of power plants remain a concern. For example, in India, 40 coal-fired power-plant projects are currently under construction, accounting for 61 GW of capacity (Mint, 2021). Despite the ongoing transition towards renewable energy in developed countries, the USA still has plans to build 10-20 GW of new gas-fired power plants in each of four major regions (i.e. Great Lakes, Northeast, Southwest and West Coast) during 2018-2022 (Burt & Ramey, 2020). In light of continued projected rises in water temperature due to climate change and power-plant expansion, it is of vital importance to understand the current status of thermal pollution in rivers and the likely impacts of the decommissioning and construction of power plants. Despite this significance, the thermal implications of power plants on freshwaters are critically understudied.

This PhD project aims to evaluate the impact of thermal pollution and predict future trends of river temperature across different spatial (global, regional, and local) and temporal (long- and short-term impact) scales. To achieve this ultimate goal, the project is split into three key aims, each representing a linked but distinct area of work, which are:

Aim 1: To map and assess the relative significance of sources of thermal pollution globally and develop an impact index for thermal pollution.

Aim 2: To explore temperature changes upstream and downstream of a power plant's thermal discharge and understand how thermal plumes change as a function of a) the power-plant operating parameters (e.g. generating capacity and time of operation) and b) prevailing hydrometeorological regimes.

Aim 3: To investigate how water temperature due to thermal effluent from power plants affects aquatic organisms.

School of Geography

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