Abstract
During summer, reservoir stratification can negatively impact source water quality. Mixing via bubble plumes (i.e., destratification) aims to minimise this. Within Blagdon Lake, a UK drinking water reservoir, a bubble plume system was found to be insufficient for maintaining homogeneity during a 2017 heatwave based on two in situ temperature chains. Air temperature will increase under future climate change which will affect stratification; this raises questions over the future applicability of these plumes. To evaluate bubble-plume performance now and in the future, AEM3D was used to simulate reservoir mixing. Calibration and validation were done on in situ measurements. The model performed well with a root mean squared error of 0.53◦ C. Twelve future meteorological scenarios from the UK Climate Projection 2018 were taken and down-scaled to sub-daily values to simulate lake response to future summer periods. The down-scaling methods, based on diurnal patterns, showed mixed results. Future model runs covered five-year intervals from 2030 to 2080. Mixing events, mean water temperatures, and Schmidt stability were evaluated. Eight scenarios showed a significant increase in water temperature, with two of these scenarios showing significant decrease in mixing events. None showed a significant increase in energy requirements. Results suggest that future climate scenarios may not alter the stratification regime; however, the warmer water may favour growth conditions for certain species of cyanobacteria and accelerate sedimentary oxygen consumption. There is some evidence of the lake changing from polymictic to a more monomictic nature. The results demonstrate bubble plumes are unlikely to maintain water column homogeneity under future climates. Modelling artificial mixing systems under future climates is a powerful tool to inform system design and reservoir management including requirements to prevent future source water quality degradation.
Original language | English |
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Article number | 2467 |
Journal | Water (Switzerland) |
Volume | 13 |
Issue number | 18 |
DOIs | |
Publication status | Published - 8 Sept 2021 |
Bibliographical note
Funding Information:Funding: This study and D.B. was supported by the Engineering and Physical Sciences Research Council in the UK via grant EP/L016214/1 awarded for the Water Informatics: Science and Engineering (WISE) Centre for Doctoral Training, which is gratefully acknowledged. E.S. was supported by a NERC GW4+ Doctoral Training Partnership studentship from the Natural Environment Research Council via grant NE/L002434/1.
Funding
Funding: This study and D.B. was supported by the Engineering and Physical Sciences Research Council in the UK via grant EP/L016214/1 awarded for the Water Informatics: Science and Engineering (WISE) Centre for Doctoral Training, which is gratefully acknowledged. E.S. was supported by a NERC GW4+ Doctoral Training Partnership studentship from the Natural Environment Research Council via grant NE/L002434/1.
Keywords
- 3D modelling
- Bubble plumes
- Stratification
ASJC Scopus subject areas
- Geography, Planning and Development
- Biochemistry
- Aquatic Science
- Water Science and Technology
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Dataset for "Stratification in a Reservoir Mixed by Bubble Plumes under Future Climate Scenarios"
Birt, D. (Creator), Zang, J. (Supervisor), Bryant, L. (Supervisor) & Slavin, E. (Data Collector), University of Bath, 8 Sept 2021
DOI: 10.15125/BATH-01036
Dataset