Identification of facies models in alluvial soil formation: The case of a Swiss alpine floodplain

Abstract

This paper describes different conceptual facies models intervening in alluvial soil formation in the case of the Sarine River floodplain, a partially embanked floodplain situated in the northwest of the Swiss Alps. Alluvial soils are submitted to processes of deposition and erosion and exhibit various characteristics reflecting the composition and properties of the material transported. Moreover, these processes of sedimentation and erosion vary in space and time and contribute thus to the heterogeneity of the whole floodplain system. Detailed analyses of the different soil layers permit a precise description of the variability and complexity of soil formation. In addition, the vertical succession of the horizons is useful to reconstruct the different natural or artificial events that occurred in this alluvial valley since the nineteenth century. On a larger scale, this study aims to contribute to floodplain management by identifying zones for restoration. The investigation was undertaken using data from 109 auger borings carried out in the Sarine River valley. Several morphological attributes of the different horizons and of the different profiles were first reduced in number and then grouped by a hierarchical agglomerative clustering. Profile factors were analysed by means of correlation analyses as well as other data summaries. The results showed positive correlations between several factors, particularly between the total profile thickness and the number of horizons found in the profile. Four facies models of alluvial soil formation are then proposed to illustrate and explain the variability of alluvial soil formation in the Sarine floodplain. Finally, these facies models are placed into the context of the Sarine floodplain scale case, according to the levels of organization of the alluvial system.

Influence of some physicochemical and biological parameters on soil structure formation in alluvial soils

“…It is a part of the floodplain of the Sarine River, tributary of the Aare River. The Sarine River is strongly confined between embankments except for the study area situated at 750 m above the sea level [9,23].…”

Spatio-temporal heterogeneity of riparian soil morphology in a restored floodplain

“…In turn, the vegetation influences soil properties such as organic matter content (Quideau et al, 2001). Through their morphology, soils also provide information on ecosystem structure, and record past and present fluvial dynamics (Gerrard, 1992;Daniels, 2003;Bullinger-Weber and Gobat, 2006). This information may be especially useful when a site has been ditched, drained, and stripped of its vegetation (Cole and Kentula, 2011).…”

Are urban soils similar to natural soils of river valleys?

“…Conversely, (2) young perturbed soils, mainly located in meadows and lawns, were shallower and were essentially formed by recent ex situ materials of different origins (e.g . Few studies reported similar trends in natural alluvial (Gerrard 1992;Bullinger-Weber and Gobat 2006;Salomé et al 2011) and urban soils (Bullock and Gregory 1991;Baumgartl 1998;Lefort et al 2007). For example, Lefort et al (2007) found higher sand, lower CEC and C org contents in human-made soils compared to natural or near natural urban soils.…”

“…Their formation is conditioned by river transport, fluvial sedimentation and by the dynamics of sur-face and groundwater (Bertrand et al 2012). The functioning of the fluvial sedimentation is a dynamic and irregular process in space and time, which results in sudden changes of textural compositions in the vertical and horizontal sections of the soil profile (Bullinger-Weber and Gobat 2006;Mendonça Santos et al 2000). Alluvial soils often accommodate genetically young deposits of baserich weathering material.…”

“…In the literature, there is nevertheless a paucity of knowledge concerning the comparison of urban and near natural alluvial soils in terms of soil evolution and its physical and chemical properties. Most of the studies refer to the direct or the indirect impacts of human activities on natural soils (Bullinger-Weber and Gobat 2006;Prokofyevaetal. 2010;Jordanova et al 2013) using soil disturbance gradients (Craul 1992;McDonnell et al 1997).…”