Using hysteresis analysis of high-resolution water quality monitoring data, including uncertainty, to infer controls on nutrient and sediment transfer in catchments.

Autor: Lloyd CEM; School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK; School of Geographical Sciences, University of Bristol, University Road, Bristol BS8 1SS, UK. Electronic address: charlotte.lloyd@bristol.ac.uk., Freer JE; School of Geographical Sciences, University of Bristol, University Road, Bristol BS8 1SS, UK., Johnes PJ; School of Geographical Sciences, University of Bristol, University Road, Bristol BS8 1SS, UK., Collins AL; Sustainable Soils and Grassland Systems Department, Rothamsted Research, North Wyke, Okehampton EX20 2SB, UK.
Jazyk: angličtina
Zdroj: The Science of the total environment [Sci Total Environ] 2016 Feb 01; Vol. 543 (Pt A), pp. 388-404. Date of Electronic Publication: 2015 Nov 18.
DOI: 10.1016/j.scitotenv.2015.11.028
Abstrakt: A large proportion of nutrients and sediment is mobilised in catchments during storm events. Therefore understanding a catchment's hydrological behaviour during storms and how this acts to mobilise and transport nutrients and sediment to nearby watercourses is extremely important for effective catchment management. The expansion of available in-situ sensors is allowing a wider range of water quality parameters to be monitored and at higher temporal resolution, meaning that the investigation of hydrochemical behaviours during storms is increasingly feasible. Studying the relationship between discharge and water quality parameters in storm events can provide a valuable research tool to infer the likely source areas and flow pathways contributing to nutrient and sediment transport. Therefore, this paper uses 2 years of high temporal resolution (15/30 min) discharge and water quality (nitrate-N, total phosphorus (TP) and turbidity) data to examine hysteretic behaviour during storm events in two contrasting catchments, in the Hampshire Avon catchment, UK. This paper provides one of the first examples of a study which comprehensively examines storm behaviours for up to 76 storm events and three water quality parameters. It also examines the observational uncertainties using a non-parametric approach. A range of metrics was used, such as loop direction, loop area and a hysteresis index (HI) to characterise and quantify the storm behaviour. With two years of high resolution information it was possible to see how transport mechanisms varied between parameters and through time. This study has also clearly shown the different transport regimes operating between a groundwater dominated chalk catchment versus a surface-water dominated clay catchment. This information, set within an uncertainty framework, means that confidence can be derived that the patterns and relationships thus identified are statistically robust. These insights can thus be used to provide information regarding transport processes and biogeochemical processing within river catchments.
(Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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