Mobilisation or dilution? Nitrate response of karst springs to high rainfall events

M. Huebsch, O. Fenton, B. Horan, D. Hennessy, K. G. Richards, P. Jordan, N. Goldscheider, C. Butscher, P. Blum

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

Nitrate (NO3−) contamination of groundwater associated with agronomic activity is of major concern in many countries. Where agriculture, thin free draining soils and karst aquifers coincide, groundwater is highly vulnerable to nitrate contamination. As residence times and denitrification potential in such systems are typically low, nitrate can discharge to surface waters unabated. However, such systems also react quickest to agricultural management changes that aim to improve water quality. In response to storm events, nitrate concentrations can alter significantly, i.e. rapidly decreasing or increasing concentrations. The current study examines the response of a specific karst spring situated on a grassland farm in South Ireland to rainfall events utilising high-resolution nitrate and discharge data together with on-farm borehole groundwater fluctuation data. Specifically, the objectives of the study are to formulate a scientific hypothesis of possible scenarios relating to nitrate responses during storm events, and to verify this hypothesis using additional case studies from the literature. This elucidates the controlling key factors that lead to mobilisation and/or dilution of nitrate concentrations during storm events. These were land use, hydrological condition and karstification, which in combination can lead to differential responses of mobilised and/or diluted nitrate concentrations. Furthermore, the results indicate that nitrate response in karst is strongly dependent on nutrient source, whether mobilisation and/or dilution occur and on the pathway taken. This will have consequences for the delivery of nitrate to a surface water receptor. The current study improves our understanding of nitrate responses in karst systems and therefore can guide environmental modellers, policy makers and drinking water managers with respect to the regulations of the European Union (EU) Water Framework Directive (WFD). In future, more research should focus on the high-resolution monitoring of karst aquifers to capture the high variability of hydrochemical processes, which occur at time intervals of hours to days.
LanguageEnglish
Pages4423-4435
JournalHydrology and Earth System Sciences
Volume18
Issue number11
DOIs
Publication statusPublished - 2014

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mobilization
karst
dilution
nitrate
rainfall
groundwater
farm
aquifer
surface water
karstification
agricultural management
environmental policy
denitrification
residence time
European Union
borehole
grassland
drinking water
agriculture
water quality

Cite this

Huebsch, M. ; Fenton, O. ; Horan, B. ; Hennessy, D. ; Richards, K. G. ; Jordan, P. ; Goldscheider, N. ; Butscher, C. ; Blum, P. / Mobilisation or dilution? Nitrate response of karst springs to high rainfall events. In: Hydrology and Earth System Sciences. 2014 ; Vol. 18, No. 11. pp. 4423-4435.
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Huebsch, M, Fenton, O, Horan, B, Hennessy, D, Richards, KG, Jordan, P, Goldscheider, N, Butscher, C & Blum, P 2014, 'Mobilisation or dilution? Nitrate response of karst springs to high rainfall events', Hydrology and Earth System Sciences, vol. 18, no. 11, pp. 4423-4435. https://doi.org/10.5194/hess-18-4423-2014

Mobilisation or dilution? Nitrate response of karst springs to high rainfall events. / Huebsch, M.; Fenton, O.; Horan, B.; Hennessy, D.; Richards, K. G.; Jordan, P.; Goldscheider, N.; Butscher, C.; Blum, P.

In: Hydrology and Earth System Sciences, Vol. 18, No. 11, 2014, p. 4423-4435.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Mobilisation or dilution? Nitrate response of karst springs to high rainfall events

AU - Huebsch, M.

AU - Fenton, O.

AU - Horan, B.

AU - Hennessy, D.

AU - Richards, K. G.

AU - Jordan, P.

AU - Goldscheider, N.

AU - Butscher, C.

AU - Blum, P.

PY - 2014

Y1 - 2014

N2 - Nitrate (NO3−) contamination of groundwater associated with agronomic activity is of major concern in many countries. Where agriculture, thin free draining soils and karst aquifers coincide, groundwater is highly vulnerable to nitrate contamination. As residence times and denitrification potential in such systems are typically low, nitrate can discharge to surface waters unabated. However, such systems also react quickest to agricultural management changes that aim to improve water quality. In response to storm events, nitrate concentrations can alter significantly, i.e. rapidly decreasing or increasing concentrations. The current study examines the response of a specific karst spring situated on a grassland farm in South Ireland to rainfall events utilising high-resolution nitrate and discharge data together with on-farm borehole groundwater fluctuation data. Specifically, the objectives of the study are to formulate a scientific hypothesis of possible scenarios relating to nitrate responses during storm events, and to verify this hypothesis using additional case studies from the literature. This elucidates the controlling key factors that lead to mobilisation and/or dilution of nitrate concentrations during storm events. These were land use, hydrological condition and karstification, which in combination can lead to differential responses of mobilised and/or diluted nitrate concentrations. Furthermore, the results indicate that nitrate response in karst is strongly dependent on nutrient source, whether mobilisation and/or dilution occur and on the pathway taken. This will have consequences for the delivery of nitrate to a surface water receptor. The current study improves our understanding of nitrate responses in karst systems and therefore can guide environmental modellers, policy makers and drinking water managers with respect to the regulations of the European Union (EU) Water Framework Directive (WFD). In future, more research should focus on the high-resolution monitoring of karst aquifers to capture the high variability of hydrochemical processes, which occur at time intervals of hours to days.

AB - Nitrate (NO3−) contamination of groundwater associated with agronomic activity is of major concern in many countries. Where agriculture, thin free draining soils and karst aquifers coincide, groundwater is highly vulnerable to nitrate contamination. As residence times and denitrification potential in such systems are typically low, nitrate can discharge to surface waters unabated. However, such systems also react quickest to agricultural management changes that aim to improve water quality. In response to storm events, nitrate concentrations can alter significantly, i.e. rapidly decreasing or increasing concentrations. The current study examines the response of a specific karst spring situated on a grassland farm in South Ireland to rainfall events utilising high-resolution nitrate and discharge data together with on-farm borehole groundwater fluctuation data. Specifically, the objectives of the study are to formulate a scientific hypothesis of possible scenarios relating to nitrate responses during storm events, and to verify this hypothesis using additional case studies from the literature. This elucidates the controlling key factors that lead to mobilisation and/or dilution of nitrate concentrations during storm events. These were land use, hydrological condition and karstification, which in combination can lead to differential responses of mobilised and/or diluted nitrate concentrations. Furthermore, the results indicate that nitrate response in karst is strongly dependent on nutrient source, whether mobilisation and/or dilution occur and on the pathway taken. This will have consequences for the delivery of nitrate to a surface water receptor. The current study improves our understanding of nitrate responses in karst systems and therefore can guide environmental modellers, policy makers and drinking water managers with respect to the regulations of the European Union (EU) Water Framework Directive (WFD). In future, more research should focus on the high-resolution monitoring of karst aquifers to capture the high variability of hydrochemical processes, which occur at time intervals of hours to days.

U2 - 10.5194/hess-18-4423-2014

DO - 10.5194/hess-18-4423-2014

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JO - Hydrology and Earth System Sciences

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JF - Hydrology and Earth System Sciences

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