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| Titel |
High-quality observation of surface imperviousness for urban runoff modelling using UAV imagery |
| VerfasserIn |
P. Tokarczyk, J. P. Leitao, J. Rieckermann, K. Schindler, F. Blumensaat |
| 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 ; 19, no. 10 ; Nr. 19, no. 10 (2015-10-21), S.4215-4228 |
| Datensatznummer |
250120829
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| Publikation (Nr.) |
 copernicus.org/hess-19-4215-2015.pdf |
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| Zusammenfassung |
Modelling rainfall–runoff in urban areas is increasingly applied to support
flood risk assessment, particularly against the background of a changing
climate and an increasing urbanization. These models typically rely on
high-quality data for rainfall and surface characteristics of the catchment
area as model input.
While recent research in urban drainage has been focusing on providing
spatially detailed rainfall data, the technological advances in remote
sensing that ease the acquisition of detailed land-use information are less
prominently discussed within the community. The relevance of such methods
increases as in many parts of the globe, accurate land-use information is
generally lacking, because detailed image data are often unavailable. Modern unmanned aerial vehicles (UAVs) allow
one to acquire high-resolution images on a local level at comparably lower
cost, performing on-demand repetitive measurements and obtaining a degree of
detail tailored for the purpose of the study.
In this study, we investigate for the first time the possibility of deriving
high-resolution imperviousness maps for urban areas from UAV imagery and of
using this information as input for urban drainage models. To do so, an
automatic processing pipeline with a modern classification method is proposed
and evaluated in a state-of-the-art urban drainage modelling exercise. In a
real-life case study (Lucerne, Switzerland), we compare imperviousness maps
generated using a fixed-wing consumer micro-UAV and standard large-format
aerial images acquired by the Swiss national mapping agency
(swisstopo). After assessing their overall accuracy, we perform an
end-to-end comparison, in which they are used as an input for an urban
drainage model. Then, we evaluate the influence which different image data
sources and their processing methods have on hydrological and hydraulic model
performance. We analyse the surface runoff of the 307 individual
subcatchments regarding relevant attributes, such as peak runoff and runoff
volume. Finally, we evaluate the model's channel flow prediction performance
through a cross-comparison with reference flow measured at the catchment
outlet.
We show that imperviousness maps generated from UAV images processed with
modern classification methods achieve an accuracy comparable to standard,
off-the-shelf aerial imagery. In the examined case study, we find that the
different imperviousness maps only have a limited influence on predicted
surface runoff and pipe flows, when traditional workflows are used. We expect
that they will have a substantial influence when more detailed modelling
approaches are employed to characterize land use and to predict surface
runoff. We conclude that UAV imagery represents a valuable alternative data
source for urban drainage model applications due to the possibility of
flexibly acquiring up-to-date aerial images at a quality compared with
off-the-shelf image products and a competitive price at the same time. We
believe that in the future, urban drainage models representing a higher
degree of spatial detail will fully benefit from the strengths of UAV
imagery. |
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