Detecting surface runoff location in a small catchment using distributed and simple observation method

Abstract

Surface runoff is one of the hydrological processes involved in floods, pollution transfer, soil erosion and mudslide. Many models allow the simulation and the mapping of surface runoff and erosion hazards. Field observations of this hydrological process are not common although they are crucial to evaluate surface runoff models and to investigate or assess different kinds of hazards linked to this process. In this study, a simple field monitoring network is implemented to assess the relevance of a surface runoff susceptibility mapping method. The network is based on spatially distributed observations (nine different locations in the catchment) of soil water content and rainfall events. These data are analyzed to determine if surface runoff occurs. Two surface runoff mechanisms are considered: surface runoff by saturation of the soil surface horizon and surface runoff by infiltration excess (also called hortonian runoff). The monitoring strategy includes continuous records of soil surface water content and rainfall with a 5 minutes time step. Soil infiltration capacity time series are calculated using field soil water content and in situ measurements of soil hydraulic conductivity. Comparison of soil infiltration capacity and rainfall intensity time series allows detecting the occurrence of surface runoff by infiltration-excess. Comparison of surface soil water content with saturated water content values allows detecting the occurrence of surface runoff by saturation of the soil surface horizon. Automatic records were complemented with direct field observations of surface runoff in the experimental catchment after each significant rainfall event. The presented observation method allows the identification of fast and short-lived surface runoff processes at a small spatial and temporal resolution in natural conditions. The results also highlight the relationship between surface runoff and factors usually integrated in surface runoff mapping such as topography, rainfall parameters, soil or land cover. This study opens interesting prospects for the use of spatially distributed measurement for surface runoff detection, spatially distributed hydrological models implementation and validation at a reasonable cost.

Use of post-event surveys of impacts on railways for the evaluation of the IRIP method for surface runoff mapping

“…Spatially distributed observations in a small catchment allowed confirming the IRIP method concept of representing different steps of surface runoff (generation, transfer, accumulation) with different maps using different factors [11]. The IRIP method has been compared with others model outputs such as SHYREG [24], CINECAR and EXZECO [25] showing the complementarity of these models.…”

“…Several methods allow the mapping of surface runoff, such as STREAM [6], SCALES [7], RuiCells [8], EXZECO [9] or Erruisoll [10]. In this paper, we focus on the IRIP method [11]- [14] -Indicator of Intense Pluvial Runoff (French Acronym) -. It is a geomatics method which produces maps of the spatial susceptibility of a territory to generate, to transfer and to accumulate surface runoff.…”

“…Concerning surface runoff maps, the evaluation is particularly complex because of the lack of surface runoff observations. Instrumentation and measurements are complex at large scale [11], [15]. Proxy data are an alternative to evaluate models.…”

Description and evaluation of a surface runoff susceptibility mapping method

“…They may be classified into various approaches: naturalistic, topographic, a combination of criteria or hydrological modeling. Naturalistic approaches often provide results consistent with the reality but they require a very good understanding of the study area, can be applied to rather small areas, and are difficult to replicate (Abudi et al, 2012;Dehotin et al, 2015a;Holzmann and Sereinig, 1997;Tetzlaff et al, 2007). Topographical approaches using information from Digital Elevation Models Langlois and Delahaye, 2002;Pons et al, 2010) have the advantage of being simple and can be automated but the mapping of surface runoff needs to take into account many other parameters such as land use or soil type.…”

Vertical and lateral soil moisture patterns on a Mediterranean karst hillslope

“…Soil moisture (θ) is an essential element of the water balance and it affects different linked processes: infiltration (Albertson and Montaldo, 2003;Cerdà, 1997;Rivera et al, 2014), runoff (Ceballos et al, 2002;Dehotin et al, 2015), subsurface flow (Gish et al, 2005), deep drainage (Eilers et al, 2007) and evapotranspiration (Chamizo et al, 2013;Rodriguez-Iturbe and Porporato, 2004;Tromp-van Meerveld and McDonnell, 2006) acting at different spatial and temporal scales (Canton et al, 2004;Entin et al, 2000;Martinez-Fernandez and Ceballos, 2003). At the same time, all those processes exert a fundamental control on θ patterns (Entekhabi et al, 1996;Tromp-van Meerveld and McDonnell, 2006;Western et al, 2004).…”