There are >3000 dams in the UK that provide >75% of national public drinking water supplies (1). These unnaturally transform river flow regimes, where typically fixed ‘compensation flows’ are released for most the year except when reservoir spillovers cause rapid downstream flushes. Excessive compensation flows can reduce water supply availability in the lead-up to and during drier month, which can trigger drought permits restricting public water use. Water supply dams also degrade river ecosystems dependent on natural flow variations where hydrological modifications can disrupt ecological processes like habitats, feeding patterns and migratory cues (2, 3, 4).
This PhD will aim to address these critical environmental and societal challenges by undertaking a multi-scaled approach across England. For this, the hydrological and ecological impacts of dams will first be assessed on a national-scale. This will then feed into regional evaluations, where the successful candidate will examine how dam flow release mechanisms are shaping water security and the ecological health in downstream environments. Optimal scenarios balancing these two demands (see 4, 5) will then be quantified across different climate change forecasts using state-of-the-art statistical analyses. Under supportive supervision, the student will become proficient in both hydrological and statistical modelling in order to achieve these goals.
While there is a national-scale, ‘big data’ focus for this PhD, the successful candidate will have the opportunity to collect field data from targeted study sites. This will not only provide additional evidence that may not be extractable from secondary datasets, but will also enhance the skills being assimilated by the student and allow them to glean greater insights into how river systems regulated by dams operate. More broadly, the successful candidate will draw on the expertise of the interdisciplinary supervisory team, who specialise translating scientific research to management solutions and work closely with water companies (2). These links to industry will help ensure that the outcomes of the PhD will translate to real-world action, where the findings will be shared with the water industry to help support dam flow release operations.
Figure 1: A dam releasing water downstream (Photo credit: Jennifer Jones).
This project is a CENTA Flagship Project.
This project does not offer a CASE studentship
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Long-term hydrological (‘Hydrology Data Explorer’) and ecological (‘Fish and Ecology Data Explorer’; SHEBAM – (3)) national-scale datasets will be leveraged from the Environment Agency. These will be assessed alongside hydrological models (DECIPHeR – (1)) to quantify flow regime controls on ecological properties (‘flow-ecology relationships’). This will feed into regional case studies, where the candidate can collect additional ecohydrological data via bespoke fieldwork monitoring campaigns. For these, flow-ecology relationships will be constructed based on ‘business as usual’ dam flow releases and for hypothetical changes to this as part of environmental improvement plans. These will be explored across different UKCP18 climate change scenarios, and the impacts that all of these dam flow release scenarios have on water security will be quantified using DECIPHeR. Trade offs between ecological health and water security will be assessed to identify optimal solutions. These findings will be shared with water companies to help guide real-world management solutions.
DRs will be awarded CENTA Training Credits (CTCs) for participation in CENTA-provided and ‘free choice’ external training. One CTC can be earned per 3 hours training, and DRs must accrue 100 CTCs across the three and a half years of their PhD.
The supervisory team will equip the candidate with an interdisciplinary knowledgebase and skillset. Training will be provided in skills relating to ‘big data’ processing management, complex statistical analyses (e.g., machine learning techniques), environmental modelling and fieldwork skills centred on ecological and hydrological modelling. The skillset that the student will assimilate during the PhD and the applied research they will deliver will be beneficial for both academic and industrial career pathways. The supervisory team will support activities including writing peer reviewed journals or reports for regional stakeholders that the student can prioritise in accordance with their career aspirations.
The Centre for Ecology and Hydrology will provide invaluable expertise and guidance on obtaining hydrological data and models, and how this could be evaluated alongside ecological data nationally. We will look to work with CEH’s ‘Floods and Drought Research Infrastructure’ programme by identifying catchments being assessed within this programme with major dam influences (e.g., the Severn).
Year 1:
Year 2:
Year 3:
Year 4 (half year):
(1) Salwey, S., Coxon, G., Pianosi, F., Lane, R., Hutton, C., Bliss Singer, M., McMillan, H. and Freer, J. (2024) Developing water supply reservoir operating rules for large-scale hydrological modelling. Hydrology and Earth System Sciences, 28(17), pp.4203-4218.
(2) White, J.C., Hannah, D.M., House, A., Beatson, S.J., Martin, A. and Wood, P.J. (2017) Macroinvertebrate responses to flow and stream temperature variability across regulated and non‐regulated rivers. Ecohydrology, 10(1), p.e1773.
(3) Krajenbrink, H.J., Acreman, M., Dunbar, M.J., Hannah, D.M., Laize, C.L. and Wood, P.J. (2019) Macroinvertebrate community responses to river impoundment at multiple spatial scales. Science of the Total Environment, 650, pp.2648-2656.
(4) Chen, W. and Olden, J.D. (2017) Designing flows to resolve human and environmental water needs in a dam-regulated river. Nature communications, 8(1), p.2158.
(5) Morley, M. and Savić, D. (2020) Water resource systems analysis for water scarcity management: the thames water case study. Water, 12(6), p.1761.
(6) England, J., Naura, M., Mant, J. and Skinner, K. (2020) Seeking river restoration appraisal best practice: Supporting wider national and international environmental goals. Water and Environment Journal, 34, pp.1003-1011.
For any enquiries related to this project please contact Dr James C. White ([email protected]).
To apply to this project:
Applications must be submitted by 23:59 GMT on Wednesday 6th January 2027.