Delivery and impact bypass in a karst aquifer with high phosphorus source and pathway potential

Per-Erik Mellander, Philip Jordan, David P. Wall, Alice R. Melland, Robert Meehan, Coran Kelly, Ger Shortle

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Conduit and other karstic flows to aquifers, connecting agricultural soils and farming activities, are considered to be the main hydrological mechanisms that transfer phosphorus from the land surface to the groundwater body of a karstified aquifer. In this study, soil source and pathway components of the phosphorus (P) transfer continuum were defined at a high spatial resolution; field-by-field soil P status and mapping of all surface karst features was undertaken in a > 30 km2 spring contributing zone. Additionally, P delivery and water discharge was monitored in the emergent spring at a sub-hourly basis for over 12 months. Despite moderate to intensive agriculture, varying soil P status with a high proportion of elevated soil P concentrations and a high karstic connectivity potential, background P concentrations in the emergent groundwater were low and indicative of being insufficient to increase the surface water P status of receiving surface waters. However, episodic P transfers via the conduit system increased the P concentrations in the spring during storm events (but not > 0.035 mg total reactive P L-1) and this process is similar to other catchments where the predominant transfer is via episodic, surface flow pathways; but with high buffering potential over karst due to delayed and attenuated runoff. These data suggest that the current definitions of risk and vulnerability for P delivery to receiving surface waters should be re-evaluated as high source risk need not necessarily result in a water quality impact. Also, inclusion of conduit flows from sparse water quality data in these systems may over-emphasise their influence on the overall status of the groundwater body.
LanguageEnglish
Pages2225-2236
JournalWater Research
Volume46
Issue number7
DOIs
Publication statusPublished - 9 Feb 2012

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bypass
karst
aquifer
phosphorus
surface water
groundwater
soil
water quality
intensive agriculture
buffering
agricultural soil
connectivity
land surface
vulnerability
spatial resolution
catchment
runoff
water

Keywords

  • Eutrophication
  • karst
  • phosphorus
  • catchments

Cite this

Mellander, P-E., Jordan, P., Wall, D. P., Melland, A. R., Meehan, R., Kelly, C., & Shortle, G. (2012). Delivery and impact bypass in a karst aquifer with high phosphorus source and pathway potential. 46(7), 2225-2236. https://doi.org/10.1016/j.watres.2012.01.048
Mellander, Per-Erik ; Jordan, Philip ; Wall, David P. ; Melland, Alice R. ; Meehan, Robert ; Kelly, Coran ; Shortle, Ger. / Delivery and impact bypass in a karst aquifer with high phosphorus source and pathway potential. 2012 ; Vol. 46, No. 7. pp. 2225-2236.
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Mellander, P-E, Jordan, P, Wall, DP, Melland, AR, Meehan, R, Kelly, C & Shortle, G 2012, 'Delivery and impact bypass in a karst aquifer with high phosphorus source and pathway potential', vol. 46, no. 7, pp. 2225-2236. https://doi.org/10.1016/j.watres.2012.01.048

Delivery and impact bypass in a karst aquifer with high phosphorus source and pathway potential. / Mellander, Per-Erik; Jordan, Philip; Wall, David P.; Melland, Alice R.; Meehan, Robert; Kelly, Coran; Shortle, Ger.

Vol. 46, No. 7, 09.02.2012, p. 2225-2236.

Research output: Contribution to journalArticle

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T1 - Delivery and impact bypass in a karst aquifer with high phosphorus source and pathway potential

AU - Mellander, Per-Erik

AU - Jordan, Philip

AU - Wall, David P.

AU - Melland, Alice R.

AU - Meehan, Robert

AU - Kelly, Coran

AU - Shortle, Ger

PY - 2012/2/9

Y1 - 2012/2/9

N2 - Conduit and other karstic flows to aquifers, connecting agricultural soils and farming activities, are considered to be the main hydrological mechanisms that transfer phosphorus from the land surface to the groundwater body of a karstified aquifer. In this study, soil source and pathway components of the phosphorus (P) transfer continuum were defined at a high spatial resolution; field-by-field soil P status and mapping of all surface karst features was undertaken in a > 30 km2 spring contributing zone. Additionally, P delivery and water discharge was monitored in the emergent spring at a sub-hourly basis for over 12 months. Despite moderate to intensive agriculture, varying soil P status with a high proportion of elevated soil P concentrations and a high karstic connectivity potential, background P concentrations in the emergent groundwater were low and indicative of being insufficient to increase the surface water P status of receiving surface waters. However, episodic P transfers via the conduit system increased the P concentrations in the spring during storm events (but not > 0.035 mg total reactive P L-1) and this process is similar to other catchments where the predominant transfer is via episodic, surface flow pathways; but with high buffering potential over karst due to delayed and attenuated runoff. These data suggest that the current definitions of risk and vulnerability for P delivery to receiving surface waters should be re-evaluated as high source risk need not necessarily result in a water quality impact. Also, inclusion of conduit flows from sparse water quality data in these systems may over-emphasise their influence on the overall status of the groundwater body.

AB - Conduit and other karstic flows to aquifers, connecting agricultural soils and farming activities, are considered to be the main hydrological mechanisms that transfer phosphorus from the land surface to the groundwater body of a karstified aquifer. In this study, soil source and pathway components of the phosphorus (P) transfer continuum were defined at a high spatial resolution; field-by-field soil P status and mapping of all surface karst features was undertaken in a > 30 km2 spring contributing zone. Additionally, P delivery and water discharge was monitored in the emergent spring at a sub-hourly basis for over 12 months. Despite moderate to intensive agriculture, varying soil P status with a high proportion of elevated soil P concentrations and a high karstic connectivity potential, background P concentrations in the emergent groundwater were low and indicative of being insufficient to increase the surface water P status of receiving surface waters. However, episodic P transfers via the conduit system increased the P concentrations in the spring during storm events (but not > 0.035 mg total reactive P L-1) and this process is similar to other catchments where the predominant transfer is via episodic, surface flow pathways; but with high buffering potential over karst due to delayed and attenuated runoff. These data suggest that the current definitions of risk and vulnerability for P delivery to receiving surface waters should be re-evaluated as high source risk need not necessarily result in a water quality impact. Also, inclusion of conduit flows from sparse water quality data in these systems may over-emphasise their influence on the overall status of the groundwater body.

KW - Eutrophication

KW - karst

KW - phosphorus

KW - catchments

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ER -