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Linking in-stream nutrient flux to land use and inter-annual hydrological variability at the watershed scale

The significance of nutrient inputs at the watershed scale is best expressed in terms of in-stream processes, compared to evaluating simple field measurements of nutrient inputs. Modeling tools are necessary to consider the complexity of river networks in the determination of the sources and processes by which nutrients are transported at the watershed scale. Mediterranean rivers are potentially vulnerable to climate change (decrease in precipitation and increase of extreme events), and identifying and quantifying nutrient pollution sources and their spatial distribution can improve water resource management at the watershed scale. We apply a hybrid process-based and statistical model (SPARROW, spatially referenced regression on watershed attributes) to a largely disturbed Mediterranean watershed in NE Spain in order to estimate the annual nitrate and phosphate loads reaching the drainage network. The model emphasized the contribution of in-stream processes in nutrient transport and retention, and the inter-annual (7 years) effects of hydrological variability on the export of nutrients from the landscape to water bodies. Although forest and grassland land cover types predominate, agricultural activities and human agglomerations were significant sources of nutrient enrichment. Nutrient flux apportionment was also linked to inter-annual hydrological variability. Exported nutrient load increased in the downstream direction and coincided with decreased in-stream nutrient removal, probably worsened by the significant chemical and geomorphological impairment found in the lower parts of the watershed

Authors would like to thank the Spanish Ministry of Economy and Competitiveness for its financial support through the projects SCARCE (Consolider-Ingenio 2010 CSD2009-00065) and CARBONET (CGL2011-30474-C02-01), as well as two anonymous reviewers for their valuable comments on an earlier version of the manuscript. R.A. benefited from a grant (FI-DGR 2012) from the Catalan Government

© Science of the Total Environment, 2012, vol. 440, p. 72-81

Elsevier

Author: Aguilera Becker, Rosana
Marcé Romero, Rafael
Sabater, Sergi
Date: 2012 December 1
Abstract: The significance of nutrient inputs at the watershed scale is best expressed in terms of in-stream processes, compared to evaluating simple field measurements of nutrient inputs. Modeling tools are necessary to consider the complexity of river networks in the determination of the sources and processes by which nutrients are transported at the watershed scale. Mediterranean rivers are potentially vulnerable to climate change (decrease in precipitation and increase of extreme events), and identifying and quantifying nutrient pollution sources and their spatial distribution can improve water resource management at the watershed scale. We apply a hybrid process-based and statistical model (SPARROW, spatially referenced regression on watershed attributes) to a largely disturbed Mediterranean watershed in NE Spain in order to estimate the annual nitrate and phosphate loads reaching the drainage network. The model emphasized the contribution of in-stream processes in nutrient transport and retention, and the inter-annual (7 years) effects of hydrological variability on the export of nutrients from the landscape to water bodies. Although forest and grassland land cover types predominate, agricultural activities and human agglomerations were significant sources of nutrient enrichment. Nutrient flux apportionment was also linked to inter-annual hydrological variability. Exported nutrient load increased in the downstream direction and coincided with decreased in-stream nutrient removal, probably worsened by the significant chemical and geomorphological impairment found in the lower parts of the watershed
Authors would like to thank the Spanish Ministry of Economy and Competitiveness for its financial support through the projects SCARCE (Consolider-Ingenio 2010 CSD2009-00065) and CARBONET (CGL2011-30474-C02-01), as well as two anonymous reviewers for their valuable comments on an earlier version of the manuscript. R.A. benefited from a grant (FI-DGR 2012) from the Catalan Government
Format: application/pdf
ISSN: 0048-9697
Document access: http://hdl.handle.net/10256/11637
Language: eng
Publisher: Elsevier
Collection: MICINN/PN 2009-2014/CSD2009-00065
MICINN/PN 2011-2013/CGL2011-30474-C02-01
ReproducciĂł digital del document publicat a: http://dx.doi.org/10.1016/j.scitotenv.2012.08.030
Articles publicats (D-CCAA)
Is part of: © Science of the Total Environment, 2012, vol. 440, p. 72-81
Rights: Tots els drets reservats
Subject: Nutrients (Medi ambient)
Nutrients (Environnement)
Ecologia fluvial
Stream ecology
Title: Linking in-stream nutrient flux to land use and inter-annual hydrological variability at the watershed scale
Type: info:eu-repo/semantics/article
Repository: DUGiDocs

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