Man-made linear flow paths at catchment scale: Identification, factors and consequences for the efficiency of vegetated filter strips

Author(s)

Rosemarie Hösl, Peter Strauss, Thomas Glade

Abstract

A vegetated filter strip (VFS) gains the best retention potential when surface runoff enters the strip as

sheet runoff. However, surface runoff convergence may take place in linear flow structures long before

approaching the river system. Limited information is available about the extent of these linear flow pathways

and the factors that may influence their occurrence in the landscape. To better understand these

effects, we carried out detailed field surveys in ten small headwater catchments in different climatic

regions in Austria. Ditches and channels directly connected to the stream network were mapped. Surface

flow pathways were calculated either with or without integrating the mapped structures. Effective

placement of retention structures may also be influenced by the accuracy of digital elevation model

(DEM) resolution. We therefore used three different DEMs with varying resolution. The catchment areas

connected directly to the stream network via linear drainage structures were identified. In seven out of

the ten catchments such unprotected areas (UA) were found. Their extent varied between 10% and 38%

of the total catchment area. Factors influencing the extent of UA were length of the road network and

annual precipitation. Without integrating the mapped linear structures, UA could not be detected in the

broad-gridded DEMs. After integration of mapped linear structures, DEM resolution did not influence

the calculated extent of UA. For our environmental setting, GIS-based design of placement of retention

structures leads to considerable errors and should be verified by fieldwork.

Organisation(s)

Department of Geography and Regional Research

Journal

Landscape and Urban Planning

Volume

104

Pages

245-252

No. of pages

8

ISSN

0169-2046

Publication date

2012

Peer reviewed

Yes

Austrian Fields of Science 2012

507001 Applied geography

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