Shallow interflow – an overriding factor in flood formation during persistent rainfall
Flooding and damage caused by long term precipitation (persistent rainfall) has grown in importance since the end of the 20th century. Whereas during heavy convective rainfall the surface runoff contributes especially to floodwater formation, the proportion of near surface interflow and return flow in the area runoff increases with increasing precipitation duration. |
Academy of Sciences – ProjectTherefore within the framework of the from the Austrian Academy of Sciences and Austrian National Hydrology Committee (IHP) supported project “Shallow Interflow”, in a cooperation between the BFW’s Institute for Natural Hazards, the Geological Survey of Austria (Technical Department of Geophysics) and the Technical Office for Geology of Dr. Pirkl, extensive methodical tests and studies were carried out in five test areas : Bromberg, Bucklige Welt (Lower Austria), Brixenbach (Tyrol), Truppenübungsplatz Wattener Lizum (Tyrol), Längental (Tyrol), and Ruggbach (Vorarlberg). These tests had the following aims:
The punctual measurements and measurements at hillslope-scale respectively on selected regionally representative sites encompass:
These results, obtained on small slope segments (points) or on slopes, shall be extrapolated on the drainage basin using available basic maps and basic maps obtained in the course of the project (substrate maps, geomorphological maps, surface-runoff-coefficient maps, maps of the dominant runoff processes) and will be used to derive maps of the relevant areas during persistent rainfall (Figure 3).
The regionalised approaches shall be tested in sub-basins, in order to derive and better understand total reaction patterns of the catchment areas. These approaches enabled for the first time an implementation of the measurement data for analogue terrain-situations (Regionalisation).
The results of the field measurements obtained in Brixenbach and Ruggbach and the hydrological modelling are included in the revision of the present Hazard zone plans through the WLV and the office of the Vorarlberg provincial government.
Markart G., B. Kohl, B. Sotier, K. Klebinder, T. Schauer, G. Bunza, H. Pirkl and R. Stern (2011): A Simple Code of Practice for the Assessment of Surface Runoff Coefficients for Alpine Soil-/Vegetation Units in Torrential Rain (Version 2.0). Report in the frame of the Interreg-SEE-Project CC-WaterS (WP7 - Water Supply Management Measures, Act 7.1).
Markart G., A. Römer, G. Bieber, H. Pirkl, K. Klebinder, C. Hörfarter, A. Ahl, A. Ita, B. Jochum, B. Kohl, G. Meissl, K. Motschka, D. Ottowitz, I. Schattauer, B. Sotier, M. Strasser, K. Suntinger und E. Winkler (2013): Abschätzung der Bandbreiten von Fließgeschwindigkeiten des oberflächennahen Zwischenabflusses in alpinen Einzugsgebieten. Endbericht - 3. Projektjahr an die Österreichische Akademie der Wissenschaften (ÖAW), Nationalkomitee Hydrologie Österreichs (IHP), ISBN-Online: 978-3-7001-7392-2; doi:10.1553/Shallow
Federal Research and Training Centre for Forests, Natural Hazards and Landscape (BFW)
Austria, 1131 Vienna, Seckendorff-Gudent-Weg 8 | Tel.: +43 1 878 38-0
Autor: Markart G.