Identifying critical source areas for phosphorus loss in Ireland using field and catchment scale ranking schemes

• Published in: Journal of hydrology (Amsterdam) 2005-03, Vol.304 (1), p.430-445
• Main Authors: Hughes, K.J., Magette, W.L., Kurz, I.
• Format: Article
• Language: English
• Subjects: agricultural runoff; agricultural soils; agricultural watersheds; Catchment management; Diffuse pollution management; environmental management; Freshwater; losses from soil; Multi-criteria analysis; nonpoint source pollution; phosphorus; phosphorus ranking schemes; pollution control; water pollution
• ISSN: 0022-1694; 1879-2707
• DOI: 10.1016/j.jhydrol.2004.07.042

Phosphorus (P) in agricultural runoff is a major pollutant in many of Ireland's surface waters. Identification of areas that are at a high risk for P loss to surface waters is a critical component of river basin management. Two P ranking schemes (PRS's) were developed for Ireland, based on multi-criteria analysis approaches proposed in both the US and Europe, to predict the relative likelihood of P loss at both the field and catchment scales. The Field PRS was evaluated by comparing predicted rankings of potential P loss and transport against measured edge-of-field Dissolved Reactive P (DRP) loss for three fields with varying soil P levels. Qualitatively, results indicated that the Field PRS rankings corresponded to the magnitudes of measured P loss for the field sites, as well as to a reasoned evaluation of the relative likelihood that the fields would lose P that would subsequently make its way to surface water. The Catchment PRS was evaluated on a total of 31 catchments and sub-catchments by comparing predicted rankings of potential P loss and transport against measured in-stream median Molybdate Reactive P (MRP). Rankings of the relative likelihood of P loss and transport predicted by the Catchment PRS were positively correlated with median in-stream MRP ( r=0.51, P