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Characterization of recession behaviour for ungauged catchments in the United Kingdom based on catchment properties.

Wilbrink, Geert-Jan (2014) Characterization of recession behaviour for ungauged catchments in the United Kingdom based on catchment properties.

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Abstract:Recession analysis is about analyzing receding stream flow under dry conditions, i.e., when stream flow is due to groundwater drainage and other subsurface flows instead of directly related to precipitation. At the moment no general or global approach exist for recession analysis in ungauged catchments, i.e., catchments where stream flow is not measured, nor are there much data yet on recession behaviour in gauged catchments in the United Kingdom. The objective of this study is to characterize recession behaviour for ungauged catchments in the United Kingdom by relating recession behaviour to catchment properties. Multiple recession analysis methods, which are based on a relation between stream flow Q and its time derivative dQ/dt, and extraction procedures, i.e., how recession period are extracted from a stream flow time series, are compared for a data set of 1194 gauged catchments. Large variations between different recession analysis methods and between individual recessions are found. This research suggest that most reliable results can be obtained when analyzing individual recessions instead of analyzing all recessions together in a cloud. A better understanding of the physical background of recession behaviour can be helpful in both validating the different recession analysis methods and explaining the variations between individual recessions of the same catchment. The most reliable method, looking at the median of individual recessions, is selected. Recession behaviour is determined for 987 catchments in the United Kingdom using this method. Clear variations in recession behaviour are found between Wales, Scotland and the different regions of England. Differences in results between the different catchments are tried to explain by relating recession behaviour to catchment characteristics as geology, land use, topography and climate. Relations between recession behaviour and catchment characteristics are found, most strongly with geology and BFIHOST, a catchment descriptor based on soil characteristics. The correlations between recession behaviour and catchment characteristics are not strong enough to reliable characterize recession behaviour in ungauged catchments. It might be possible to find stronger correlations using more quantitative data for geology and land use. That could make reliable characterization of recession behaviour in ungauged catchments possible in future research.
Item Type:Essay (Bachelor)
Faculty:ET: Engineering Technology
Subject:56 civil engineering
Programme:Civil Engineering BSc (56952)
Link to this item:http://purl.utwente.nl/essays/66665
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