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| Titel |
Landscape predictors of channel wetted width at baseflow using air photos |
| VerfasserIn |
Barry Rawlins, Liam Clark, Doreen Boyd |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250073578
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| Zusammenfassung |
| Evasion of carbon dioxide from the surface of freshwater channels accounts for a substantial
proportion of its flux from the terrestrial biosphere to the atmosphere; accurate estimates of
channel wetted width (WW) are required to improve predictions of this flux. We investigated
which landscape and climate-related data were statistically significant predictors of
WW at baseflow across a large region (2200Â km2) of north Wales and western
England (UK) where habitat surveys suggest the majority of channels are in a near
natural state. We used 25Â cm pixel resolution air photos to measure channel WW at
baseflow, and quantified the magnitude of the errors in these measurements. We used
flow information from local gauging stations to ensure that channels were at or
close to baseflow for the days on which the air photos were captured. The root
mean squared difference between the field-based and air photo measurements of
WW (n=28 sites) was small (0.14Â m) in comparison to the median channel WW
(3.07Â m), and there was very little bias between the two sets of measurements
(0.026Â m).
We created a set of points along those sections of channels which were visible in air
photos and used a digital terrain model to create the drainage catchments for the points and
computed their catchment area (CA). We removed points with CA |
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