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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 and Shortle, Ger (2012) Delivery and impact bypass in a karst aquifer with high phosphorus source and pathway potential. Water Research, 46 (7). pp. 2225-2236. [Journal article]

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URL: http://www.sciencedirect.com/science/article/pii/S0043135412000802

DOI: 10.1016/j.watres.2012.01.048


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.

Item Type:Journal article
Keywords:Eutrophication, karst, phosphorus, catchments
Faculties and Schools:Faculty of Life and Health Sciences > School of Geography and Environmental Sciences
Faculty of Life and Health Sciences
Research Institutes and Groups:Environmental Sciences Research Institute
Environmental Sciences Research Institute > Freshwater Sciences
ID Code:21407
Deposited By: Professor Phil Jordan
Deposited On:22 Apr 2012 11:14
Last Modified:19 Sep 2016 10:51

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