Effects of spatial variability on the rainfall runoff process in a small loess catchment

Citation
B. Merz et A. Bardossy, Effects of spatial variability on the rainfall runoff process in a small loess catchment, J HYDROL, 213(1-4), 1998, pp. 304-317
Citations number
42
Categorie Soggetti
Environment/Ecology,"Civil Engineering
Journal title
JOURNAL OF HYDROLOGY
ISSN journal
00221694 → ACNP
Volume
213
Issue
1-4
Year of publication
1998
Pages
304 - 317
Database
ISI
SICI code
0022-1694(199812)213:1-4<304:EOSVOT>2.0.ZU;2-2
Abstract
Numerous field experiments have revealed that hydrological processes and pa rameters can show considerable spatial variability. When modelling the rain fall runoff process, the influence of this variability on the runoff should be assessed. For regionalization purposes, it is an important question if and how this variability is reflected in the behaviour on a larger scale. A quasi-three-dimensional, process-oriented model is used to understand the influence of spatial variability on the runoff behaviour. The study area, " Neuenburger Pfad", is a small loess catchment in southwestern Germany. Beca use of low infiltration capacity of the loess soil, runoff is produced by i nfiltration excess overland flow. Three examples are presented which elabor ate on the effects of different types of spatial variability. The first exa mple shows that an agricultural road plays a crucial role in the runoff beh aviour of the investigated catchment. The second example studies the role o f the spatial distribution of soil parameters. It demonstrates the importan ce of structured variability in heterogeneous fields. Purely random fields result in hydrographs similar to the homogeneous case, whereas fields with structured variability yield very different runoff. The third example is co ncerned with the effects of different soil moisture interpolations, which s erve as initial state for the runoff model. The examples presented show tha t spatial variability can have a dominant influence on the rainfall runoff behaviour. For sound modelling, a close inspection of the particular catchm ent characteristics is necessary. Structured variability should be included in hydrological models because of the larger influence compared to stochas tic variability. To understand the extent and the significance of catchment variability, an interdiciplinary teamwork should be fruitful. (C) 1998 Pub lished by Elsevier Science B.V. All rights reserved.