Relation between floodplain land use and river hydromorphology on different spatial scales a case study from two lower-mountain catchments in Germany

Abstract

The influence of land use on the hydromorphological state of streams has rarely been investigated and most of the studies focused on catchment land use. Moreover, contrasting results were reported. The objective of our study was to investigate the relation between local hydromorphology and land use on different spatial scales, to identify spatial scales of special importance, and to test, if it is possible to predict hydromorphology using land use data. We differentiated between two lateral spatial scales (buffer and floodplain) and three longitudinal scales (site, reach, catchment). The results indicate that the hydromorphological state of streams is significantly related to the land use on all spatial scales investigated. Differences are small, but there is some evidence that land use on the floodplain and on the reach scale is of special importance. Considering different spatial scales simultaneously distinctly increases model predictability. But even the variance of the hydromorphological data explained by these statistical models (20-41 %) is too low to use land use as a predictor for specific channel characteristics. Land use data are better suited to predict the overall hydromorphological state of the study streams. Moreover, it is possible to derive statistically significant relations between single land use categories and single hydromorphological parameters.