Divergent future drought projections in UK river flows and groundwater levels
<p>Hydrological drought is a serious issue globally, which is likely to be amplified by 21st century climate change. In the UK, the impacts of changes in river flow and groundwater drought severity in a future of climate change and higher water demand are potentially severe. Recent publication...
| Main Authors: | , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2024-02-01
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| Series: | Hydrology and Earth System Sciences |
| Online Access: | https://hess.copernicus.org/articles/28/417/2024/hess-28-417-2024.pdf |
| _version_ | 1827357785469222912 |
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| author | S. Parry J. D. Mackay J. D. Mackay T. Chitson J. Hannaford J. Hannaford E. Magee M. Tanguy V. A. Bell K. Facer-Childs A. Kay R. Lane R. J. Moore S. Turner J. Wallbank |
| author_facet | S. Parry J. D. Mackay J. D. Mackay T. Chitson J. Hannaford J. Hannaford E. Magee M. Tanguy V. A. Bell K. Facer-Childs A. Kay R. Lane R. J. Moore S. Turner J. Wallbank |
| author_sort | S. Parry |
| collection | DOAJ |
| description | <p>Hydrological drought is a serious issue globally, which is likely to be amplified by 21st century climate change. In the UK, the impacts of changes in river flow and groundwater drought severity in a future of climate change and higher water demand are potentially severe. Recent publication of a new nationally consistent set of river flow and groundwater level projections (the eFLaG dataset), based on state-of-the-art UKCP18 climate projections, offers a unique opportunity to quantitatively assess future UK hydrological drought susceptibility. The dataset includes a transient, multi-model ensemble of hydrological projections driven by a single regional climate model (RCM), with a 12-member perturbed-parameter ensemble, for 200 catchments and 54 boreholes spanning a period from 1961 to 2080. Assessment of a baseline period (1989–2018) shows that the RCM-driven projections adequately reproduce observed river flow and groundwater level regimes, improving our confidence in using these models for assessment of future drought. Across all hydrological models and most catchments, future low river flows are projected to decline consistently out to 2080. Drought durations, intensities and severities are all projected to increase in most (over 90 %, pooling across different drought characteristics) UK catchments. However, the trajectory of low groundwater levels and groundwater drought characteristics diverges from that of river flows. Whilst groundwater levels at most (<span class="inline-formula">></span> 85 %) boreholes are projected to decline (consistent with river flows), these declines are relatively modest (<span class="inline-formula"><</span> 10 % reduction) in transient low groundwater levels by 2080, and, in fact, six show moderate increases. Groundwater drought characteristics in the far future (2050–2079) are often similar to those of the baseline (1989–2018), with only 33 % of boreholes showing an increase (towards worsening drought) of more than 10 % for drought severity (48 % of boreholes for drought intensity). Interestingly, for some boreholes, droughts are projected to be more prolonged and severe in the near future (2020–2049) before returning to shorter durations and lower severity in the far future. A number of explanatory factors for this divergence between river flow and groundwater are discussed. The sensitivity to seasonal changes in precipitation and potential evapotranspiration is proposed as a principal driver of divergence because low river flows are more influenced by shorter-term rainfall deficits in the summer half-year, whilst groundwater drought appears to be offset somewhat by the wetter winter signal in the RCM projections. Our results have important implications for water management, demonstrating a widespread increase in river flow drought severity and diminishing low flows that could have profound societal and environmental impacts unless mitigated. Furthermore, the divergence in projections of drought in river flows and groundwater levels brings into question the balance between surface and subsurface water resources. The projected contrast in fortunes of surface and subsurface water resources identified for the UK may be replicated in other parts of the world where climate projections suggest a shift towards drier summers and wetter winters.</p> |
| first_indexed | 2024-03-08T05:52:59Z |
| format | Article |
| id | doaj.art-c293e51f76cf45fda8b4568ca08be7c1 |
| institution | Directory Open Access Journal |
| issn | 1027-5606 1607-7938 |
| language | English |
| last_indexed | 2024-03-08T05:52:59Z |
| publishDate | 2024-02-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Hydrology and Earth System Sciences |
| spelling | doaj.art-c293e51f76cf45fda8b4568ca08be7c12024-02-05T07:43:15ZengCopernicus PublicationsHydrology and Earth System Sciences1027-56061607-79382024-02-012841744010.5194/hess-28-417-2024Divergent future drought projections in UK river flows and groundwater levelsS. Parry0J. D. Mackay1J. D. Mackay2T. Chitson3J. Hannaford4J. Hannaford5E. Magee6M. Tanguy7V. A. Bell8K. Facer-Childs9A. Kay10R. Lane11R. J. Moore12S. Turner13J. Wallbank14UK Centre for Ecology & Hydrology, Wallingford, OX10 8BB, UKBritish Geological Survey, Keyworth, Nottingham, NG12 5GG, UKSchool of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, B15 2TT, UKUK Centre for Ecology & Hydrology, Wallingford, OX10 8BB, UKUK Centre for Ecology & Hydrology, Wallingford, OX10 8BB, UKIrish Climate And Research UnitS (ICARUS), Maynooth, Co. Kildare, IrelandUK Centre for Ecology & Hydrology, Wallingford, OX10 8BB, UKUK Centre for Ecology & Hydrology, Wallingford, OX10 8BB, UKUK Centre for Ecology & Hydrology, Wallingford, OX10 8BB, UKUK Centre for Ecology & Hydrology, Wallingford, OX10 8BB, UKUK Centre for Ecology & Hydrology, Wallingford, OX10 8BB, UKUK Centre for Ecology & Hydrology, Wallingford, OX10 8BB, UKUK Centre for Ecology & Hydrology, Wallingford, OX10 8BB, UKUK Centre for Ecology & Hydrology, Wallingford, OX10 8BB, UKUK Centre for Ecology & Hydrology, Wallingford, OX10 8BB, UK<p>Hydrological drought is a serious issue globally, which is likely to be amplified by 21st century climate change. In the UK, the impacts of changes in river flow and groundwater drought severity in a future of climate change and higher water demand are potentially severe. Recent publication of a new nationally consistent set of river flow and groundwater level projections (the eFLaG dataset), based on state-of-the-art UKCP18 climate projections, offers a unique opportunity to quantitatively assess future UK hydrological drought susceptibility. The dataset includes a transient, multi-model ensemble of hydrological projections driven by a single regional climate model (RCM), with a 12-member perturbed-parameter ensemble, for 200 catchments and 54 boreholes spanning a period from 1961 to 2080. Assessment of a baseline period (1989–2018) shows that the RCM-driven projections adequately reproduce observed river flow and groundwater level regimes, improving our confidence in using these models for assessment of future drought. Across all hydrological models and most catchments, future low river flows are projected to decline consistently out to 2080. Drought durations, intensities and severities are all projected to increase in most (over 90 %, pooling across different drought characteristics) UK catchments. However, the trajectory of low groundwater levels and groundwater drought characteristics diverges from that of river flows. Whilst groundwater levels at most (<span class="inline-formula">></span> 85 %) boreholes are projected to decline (consistent with river flows), these declines are relatively modest (<span class="inline-formula"><</span> 10 % reduction) in transient low groundwater levels by 2080, and, in fact, six show moderate increases. Groundwater drought characteristics in the far future (2050–2079) are often similar to those of the baseline (1989–2018), with only 33 % of boreholes showing an increase (towards worsening drought) of more than 10 % for drought severity (48 % of boreholes for drought intensity). Interestingly, for some boreholes, droughts are projected to be more prolonged and severe in the near future (2020–2049) before returning to shorter durations and lower severity in the far future. A number of explanatory factors for this divergence between river flow and groundwater are discussed. The sensitivity to seasonal changes in precipitation and potential evapotranspiration is proposed as a principal driver of divergence because low river flows are more influenced by shorter-term rainfall deficits in the summer half-year, whilst groundwater drought appears to be offset somewhat by the wetter winter signal in the RCM projections. Our results have important implications for water management, demonstrating a widespread increase in river flow drought severity and diminishing low flows that could have profound societal and environmental impacts unless mitigated. Furthermore, the divergence in projections of drought in river flows and groundwater levels brings into question the balance between surface and subsurface water resources. The projected contrast in fortunes of surface and subsurface water resources identified for the UK may be replicated in other parts of the world where climate projections suggest a shift towards drier summers and wetter winters.</p>https://hess.copernicus.org/articles/28/417/2024/hess-28-417-2024.pdf |
| spellingShingle | S. Parry J. D. Mackay J. D. Mackay T. Chitson J. Hannaford J. Hannaford E. Magee M. Tanguy V. A. Bell K. Facer-Childs A. Kay R. Lane R. J. Moore S. Turner J. Wallbank Divergent future drought projections in UK river flows and groundwater levels Hydrology and Earth System Sciences |
| title | Divergent future drought projections in UK river flows and groundwater levels |
| title_full | Divergent future drought projections in UK river flows and groundwater levels |
| title_fullStr | Divergent future drought projections in UK river flows and groundwater levels |
| title_full_unstemmed | Divergent future drought projections in UK river flows and groundwater levels |
| title_short | Divergent future drought projections in UK river flows and groundwater levels |
| title_sort | divergent future drought projections in uk river flows and groundwater levels |
| url | https://hess.copernicus.org/articles/28/417/2024/hess-28-417-2024.pdf |
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