Quantification of phosphorus transport from a karstic agricultural watershed to emerging spring water

Mellander, Per-Erik and Jordan, Philip and Melland, Alice R. and Murphy, Paul N. C. and Wall, David P. and Mechan, Sarah and Meehan, Robert and Kelly, Coran and Shine, Oliver and Shortle, Ger (2013) Quantification of phosphorus transport from a karstic agricultural watershed to emerging spring water. Environmental Science and Technology, 47 (12). pp. 6111-6119. ISSN 0013-936X


The degree to which waters in a given watershed will be affected by nutrient export can be defined as that watershed's nutrient vulnerability. This study applied concepts of specific phosphorus (P) vulnerability to develop intrinsic groundwater vulnerability risk assessments in a 32 km2 karst watershed (spring zone of contribution) in a relatively intensive agricultural landscape. To explain why emergent spring water was below an ecological impairment threshold, concepts of P attenuation potential were investigated along the nutrient transfer continuum based on soil P buffering, depth to bedrock, and retention within the aquifer. Surface karst features, such as enclosed depressions, were reclassified based on P attenuation potential in soil at the base. New techniques of high temporal resolution monitoring of P loads in the emergent spring made it possible to estimate P transfer pathways and retention within the aquifer and indicated small–medium fissure flows to be the dominant pathway, delivering 52–90% of P loads during storm events. Annual total P delivery to the main emerging spring was 92.7 and 138.4 kg total P (and 52.4 and 91.3 kg as total reactive P) for two monitored years, respectively. A revised groundwater vulnerability assessment was used to produce a specific P vulnerability map that used the soil and hydrogeological P buffering potential of the watershed as key assumptions in moderating P export to the emergent spring. Using this map and soil P data, the definition of critical source areas in karst landscapes was demonstrated.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: © 2013 American Chemical Society. Permanent restricted access to published version in accordance with the copyright policy of the publisher.
Faculty / Department / School: Historic - Faculty of Engineering and Surveying - Department of Agricultural, Civil and Environmental Engineering
Date Deposited: 17 Aug 2014 23:57
Last Modified: 07 Mar 2017 04:28
Uncontrolled Keywords: agricultural landscapes; agricultural watersheds; critical source areas; groundwater vulnerability assessments; high temporal resolution; phosphorus transport; vulnerability maps
Fields of Research : 04 Earth Sciences > 0406 Physical Geography and Environmental Geoscience > 040608 Surfacewater Hydrology
07 Agricultural and Veterinary Sciences > 0701 Agriculture, Land and Farm Management > 070107 Farming Systems Research
07 Agricultural and Veterinary Sciences > 0799 Other Agricultural and Veterinary Sciences > 079901 Agricultural Hydrology (Drainage, Flooding, Irrigation, Quality, etc.)
Socio-Economic Objective: D Environment > 96 Environment > 9611 Physical and Chemical Conditions of Water > 961103 Physical and Chemical Conditions of Water in Fresh, Ground and Surface Water Environments (excl. Urban and Industrial Use)
Identification Number or DOI: 10.1021/es304909y
URI: http://eprints.usq.edu.au/id/eprint/25781

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