Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6432994 | Geomorphology | 2011 | 20 Pages |
Our understanding about the regional variation of Sediment Yield (SY) in Europe and its scale dependency currently relies on a limited number of data for mainly larger river systems. SY is the integrated result of all erosion and sediment transporting processes operating in a catchment and is therefore of high value for environmental studies and monitoring purposes. Most global assessments of SY consider catchment area (A), climate and topography as the main explanatory variables. However, it is still unclear if these factors also control regional variations of SY within Europe. This paper aims at bridging this gap. Therefore, we i) present a large database of SY-values which was constructed through an extensive literature review; ii) describe the spatial patterns of SY across Europe; and iii) explore its relation with A, climate, and topography.In total, sediment yield data from 1794 different locations throughout Europe were collected (507 reservoirs and 1287 gauging stations), representing a minimum of 29,203 catchment-year data. Only SY-data measured at gauging stations or derived from reservoir siltation rates over a period of a minimum of one year were included in the database. This database comprises a large range of catchment areas (A): i.e from small upland catchments (â¥Â 0.01 km²) to major European river basins (â¤1,360,000 km²). An overview of the collected SY-data is provided and sources of uncertainty on the available data are discussed.Despite potentially large uncertainties on several of the individual SY-values, analysis of this database indicates clear spatial patterns of SY in Europe. The temperate and relatively flat regions of Western, Northern and Central Europe generally have relatively low SY-values (with ca. 50% of the SY < 40 t kmâ2 yrâ1 and ca. 80% of the data < 200 t kmâ2 yrâ1), while Mediterranean and Mountainous regions generally have higher SY-values (with around 85% of the SY-data > 40 t kmâ2 yrâ1 and more than 50% of the data > 200 t kmâ2 yrâ1). These differences are attributed to a combination of factors, such as differences in climate, topography, lithology and land use. Although larger differences in SY were found between the climatic regions than between topographic zones, it is currently difficult to identify the individual importance of the various controlling factors of SY.SY-A relationships were calculated for the entire dataset and for subgroups stratified according to the measurement method (gauging stations or reservoir surveys), range of the catchment area, climatic region, topographic zone of the river outlet, and major European river system. Although typically a negative relationship between SY and A is expected due to a decrease in topsoil erosion rates on more gentle slopes and an increase in sediment deposition with an increase in catchment size, this relationship was found to be generally very weak and subject to a lot of scatter. Furthermore, results illustrate important differences in scale dependency: whereas a weak but significant negative trend is generally observed for the temperate and relatively flat regions, no significant or even positive trends were observed in mountain regions and Mediterranean Europe. When only larger river catchments (i.e. > 100 km² and especially >10,000 km²) are considered, catchment area exerted a larger control on SY. These findings confirm previous studies and indicate that the relationship between SY, spatial scale and other controlling factors is often complex and non-linear.
Research highlights⺠A sediment yield (SY) database from 1794 European catchments was compiled. ⺠Overall, highest SY-values occur in Mediterranean and mountain regions. ⺠Catchment area (A) poorly explains observed variation in SY. ⺠Scale dependency of SY varies between regions and the considered range of A. ⺠Climate, topography and A do not completely explain regional variation in SY.