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| Titel |
Hydrochemical processes in lowland rivers: insights from in situ, high-resolution monitoring |
| VerfasserIn |
A. J. Wade, E. J. Palmer-Felgate, S. J. Halliday, R. A. Skeffington, M. Loewenthal, H. P. Jarvie, M. J. Bowes, G. M. Greenway, S. J. Haswell, I. M. Bell, E. Joly, A. Fallatah, C. Neal, R. J. Williams, E. Gozzard, J. R. Newman |
| 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 ; 16, no. 11 ; Nr. 16, no. 11 (2012-11-22), S.4323-4342 |
| Datensatznummer |
250013577
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| Publikation (Nr.) |
 copernicus.org/hess-16-4323-2012.pdf |
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| Zusammenfassung |
| This paper introduces new insights into the hydrochemical functioning of
lowland river systems using field-based spectrophotometric and electrode
technologies. The streamwater concentrations of nitrogen species and
phosphorus fractions were measured at hourly intervals on a continuous basis
at two contrasting sites on tributaries of the River Thames – one draining a
rural catchment, the River Enborne, and one draining a more urban system,
The Cut. The measurements complement those from an existing network of
multi-parameter water quality sondes maintained across the Thames catchment
and weekly monitoring based on grab samples. The results of the sub-daily
monitoring show that streamwater phosphorus concentrations display highly
complex dynamics under storm conditions dependent on the antecedent
catchment wetness, and that diurnal phosphorus and nitrogen cycles occur
under low flow conditions. The diurnal patterns highlight the dominance of
sewage inputs in controlling the streamwater phosphorus and nitrogen
concentrations at low flows, even at a distance of 7 km from the nearest
sewage treatment works in the rural River Enborne. The time of sample
collection is important when judging water quality against ecological
thresholds or standards. An exhaustion of the supply of phosphorus from
diffuse and multiple septic tank sources during storm events was evident and
load estimation was not improved by sub-daily monitoring beyond that
achieved by daily sampling because of the eventual reduction in the
phosphorus mass entering the stream during events. The results highlight the
utility of sub-daily water quality measurements and the discussion considers
the practicalities and challenges of in situ, sub-daily monitoring. |
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