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| Titel |
Flow pathways and nutrient transport mechanisms drive hydrochemical sensitivity to climate change across catchments with different geology and topography |
| VerfasserIn |
J. Crossman, M. N. Futter, P. G. Whitehead, E. Stainsby, H. M. Baulch, L. Jin, S. K. Oni, R. L. Wilby, P. J. Dillon |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 18, no. 12 ; Nr. 18, no. 12 (2014-12-12), S.5125-5148 |
| Datensatznummer |
250120561
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| Publikation (Nr.) |
 copernicus.org/hess-18-5125-2014.pdf |
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| Zusammenfassung |
| Hydrological processes determine the transport of nutrients and passage of
diffuse pollution. Consequently, catchments are likely to exhibit individual
hydrochemical responses (sensitivities) to climate change, which are
expected to alter the timing and amount of runoff, and to impact in-stream
water quality. In developing robust catchment management strategies and
quantifying plausible future hydrochemical conditions it is therefore
equally important to consider the potential for spatial variability in, and
causal factors of, catchment sensitivity, as it is to explore future changes in
climatic pressures. This study seeks to identify those factors which
influence hydrochemical sensitivity to climate change. A perturbed physics
ensemble (PPE), derived from a series of global climate model (GCM) variants
with specific climate sensitivities was used to project future climate
change and uncertainty. Using the INtegrated CAtchment model of Phosphorus
dynamics (INCA-P), we quantified potential hydrochemical responses in four
neighbouring catchments (with similar land use but varying topographic and
geological characteristics) in southern Ontario, Canada. Responses were
assessed by comparing a 30 year baseline (1968–1997) to two future periods:
2020–2049 and 2060–2089. Although projected climate change and uncertainties
were similar across these catchments, hydrochemical responses (sensitivities)
were highly varied. Sensitivity was governed by quaternary geology
(influencing flow pathways) and nutrient transport mechanisms. Clay-rich
catchments were most sensitive, with total phosphorus (TP) being rapidly
transported to rivers via overland flow. In these catchments large annual
reductions in TP loads were projected. Sensitivity in the other two
catchments, dominated by sandy loams, was lower due to a larger proportion
of soil matrix flow, longer soil water residence times and seasonal
variability in soil-P saturation. Here smaller changes in TP loads,
predominantly increases, were projected. These results suggest that the clay
content of soils could be a good indicator of the sensitivity of catchments
to climatic input, and reinforces calls for catchment-specific management plans. |
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