The significance of groundwater contributions to New Zealand rivers
Groundwater and surface water are highly interconnected systems, with the connections varying spatially, temporally and by catchment. Representing this connectivity is of key importance for future effective water management, and to address the global decline of surface water flows. Previous studies...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2025-07-01
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| Series: | Frontiers in Water |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/frwa.2025.1584947/full |
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| author | Catherine Moore Paul Oluwunmi Brioch Hemmings Stewart Cameron Jing Yang Mike Taves Channa Rajanayaka Simon J. R. Woodward Magali Moreau |
| author_facet | Catherine Moore Paul Oluwunmi Brioch Hemmings Stewart Cameron Jing Yang Mike Taves Channa Rajanayaka Simon J. R. Woodward Magali Moreau |
| author_sort | Catherine Moore |
| collection | DOAJ |
| description | Groundwater and surface water are highly interconnected systems, with the connections varying spatially, temporally and by catchment. Representing this connectivity is of key importance for future effective water management, and to address the global decline of surface water flows. Previous studies have used baseflow separation methods to quantify the groundwater contribution to surface flow volumes. However, few studies have analysed the different dynamics of deep and shallower groundwater contributions to surface water flow rates across the flow regime and attempted to quantify this changing contribution. We analysed the distribution of fast (near-surface event flow), medium (seasonal shallow groundwater discharge) and slow (deeper groundwater) pathways into surface water flows for a case study involving 58 river water quality and flow monitoring sites across New Zealand. This involved a novel application of the chemistry assisted baseflow separation method (BACH). We found that shallow and deep groundwater pathways were the most significant contributor (>80% of the daily flow rate) to river flow at most sites at the 75th flow percentile, and for many sites even at the 95th flow percentile. These findings emphasise the need to better integrate groundwater into surface water management strategies, particularly as droughts intensify, floods become more frequent and severe, and legacy nutrient input increases under changing climate and land-use. |
| format | Article |
| id | doaj-art-da13c2124e1e4e80b32f55e012d7b638 |
| institution | Kabale University |
| issn | 2624-9375 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Water |
| spelling | doaj-art-da13c2124e1e4e80b32f55e012d7b6382025-08-20T03:27:43ZengFrontiers Media S.A.Frontiers in Water2624-93752025-07-01710.3389/frwa.2025.15849471584947The significance of groundwater contributions to New Zealand riversCatherine Moore0Paul Oluwunmi1Brioch Hemmings2Stewart Cameron3Jing Yang4Mike Taves5Channa Rajanayaka6Simon J. R. Woodward7Magali Moreau8GNS Science, Lower Hutt, New ZealandGNS Science, Lower Hutt, New ZealandINTERA Incorporated, Austin, TX, United StatesGNS Science, Lower Hutt, New ZealandNational Institute of Water and Atmospheric Research (NIWA), Auckland, New ZealandGNS Science, Lower Hutt, New ZealandNational Institute of Water and Atmospheric Research (NIWA), Auckland, New ZealandDairyNZ, Hamilton, New ZealandGNS Science, Lower Hutt, New ZealandGroundwater and surface water are highly interconnected systems, with the connections varying spatially, temporally and by catchment. Representing this connectivity is of key importance for future effective water management, and to address the global decline of surface water flows. Previous studies have used baseflow separation methods to quantify the groundwater contribution to surface flow volumes. However, few studies have analysed the different dynamics of deep and shallower groundwater contributions to surface water flow rates across the flow regime and attempted to quantify this changing contribution. We analysed the distribution of fast (near-surface event flow), medium (seasonal shallow groundwater discharge) and slow (deeper groundwater) pathways into surface water flows for a case study involving 58 river water quality and flow monitoring sites across New Zealand. This involved a novel application of the chemistry assisted baseflow separation method (BACH). We found that shallow and deep groundwater pathways were the most significant contributor (>80% of the daily flow rate) to river flow at most sites at the 75th flow percentile, and for many sites even at the 95th flow percentile. These findings emphasise the need to better integrate groundwater into surface water management strategies, particularly as droughts intensify, floods become more frequent and severe, and legacy nutrient input increases under changing climate and land-use.https://www.frontiersin.org/articles/10.3389/frwa.2025.1584947/fullbaseflow separationBayesianchemistry-assisted hydrograph separationgroundwatersurface water-groundwater exchange |
| spellingShingle | Catherine Moore Paul Oluwunmi Brioch Hemmings Stewart Cameron Jing Yang Mike Taves Channa Rajanayaka Simon J. R. Woodward Magali Moreau The significance of groundwater contributions to New Zealand rivers Frontiers in Water baseflow separation Bayesian chemistry-assisted hydrograph separation groundwater surface water-groundwater exchange |
| title | The significance of groundwater contributions to New Zealand rivers |
| title_full | The significance of groundwater contributions to New Zealand rivers |
| title_fullStr | The significance of groundwater contributions to New Zealand rivers |
| title_full_unstemmed | The significance of groundwater contributions to New Zealand rivers |
| title_short | The significance of groundwater contributions to New Zealand rivers |
| title_sort | significance of groundwater contributions to new zealand rivers |
| topic | baseflow separation Bayesian chemistry-assisted hydrograph separation groundwater surface water-groundwater exchange |
| url | https://www.frontiersin.org/articles/10.3389/frwa.2025.1584947/full |
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