Review of the paper: How does initial soil moisture influence the hydrological response? A case study from southern France of Magdalena Uber et al.

2018 ◽  
Author(s):  
Anonymous
Keyword(s):  
Soil Moisture ◽  
Hydrological Response ◽  
Southern France ◽  
Initial Soil Moisture ◽  
Initial Soil ◽  
Moisture Influence

scholarly journals How does initial soil moisture influence the hydrological response? A case study from southern France

2018 ◽  
Vol 22 (12) ◽  
pp. 6127-6146 ◽  
Author(s):  
Magdalena Uber ◽  
Jean-Pierre Vandervaere ◽  
Isabella Zin ◽  
Isabelle Braud ◽  
Maik Heistermann ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Hydrological Response ◽  
Hydrograph Separation ◽  
Catchment Scale ◽  
Southern France ◽  
Initial Soil Moisture ◽  
Wide Range ◽  
Initial Soil ◽  
Rain Events ◽  
The Impact

Abstract. The Cévennes–Vivarais region in southern France is prone to heavy rainfall that can lead to flash floods which are one of the most hazardous natural risks in Europe. The results of numerous studies show that besides rainfall and physical catchment characteristics the catchment's initial soil moisture also impacts the hydrological response to rain events. The aim of this paper is to analyze the relationship between catchment mean initial soil moisture θ̃ini and the hydrological response that is quantified using the event-based runoff coefficient ϕev in the two nested catchments of the Gazel (3.4 km2) and the Claduègne (43 km2). Thus, the objectives are twofold: (1) obtaining meaningful estimates of soil moisture at catchment scale from a dense network of in situ measurements and (2) using this estimate of θ̃ini to analyze its relation with ϕev calculated for many runoff events. A sampling setup including 45 permanently installed frequency domain reflectancy probes that continuously measure soil moisture at three depths is applied. Additionally, on-alert surface measurements at ≈10 locations in each one of 11 plots are conducted. Thus, catchment mean soil moisture can be confidently assessed with a standard error of the mean of ≤1.7 vol % over a wide range of soil moisture conditions. The ϕev is calculated from high-resolution discharge and precipitation data for several rain events with a cumulative precipitation Pcum ranging from less than 5 mm to more than 80 mm. Because of the high uncertainty of ϕev associated with the hydrograph separation method, ϕev is calculated with several methods, including graphical methods, digital filters and a tracer-based method. The results indicate that the hydrological response depends on θ̃ini: during dry conditions ϕev is consistently below 0.1, even for events with high and intense precipitation. Above a threshold of θ̃ini=34 vol % ϕev can reach values up to 0.99 but there is a high scatter. Some variability can be explained with a weak correlation of ϕev with Pcum and rain intensity, but a considerable part of the variability remains unexplained. It is concluded that threshold-based methods can be helpful to prevent overestimation of the hydrological response during dry catchment conditions. The impact of soil moisture on the hydrological response during wet catchment conditions, however, is still insufficiently understood and cannot be generalized based on the present results.

scholarly journals How does initial soil moisture influence the hydrological response? A case study from southern France

2018 ◽  
Author(s):  
Magdalena Uber ◽  
Jean-Pierre Vandervaere ◽  
Isabella Zin ◽  
Isabelle Braud ◽  
Maik Heistermann ◽  
...  
Keyword(s):  
Land Use ◽  
Soil Moisture ◽  
Spatial And Temporal Variability ◽  
Hydrological Response ◽  
Southern France ◽  
Initial Soil Moisture ◽  
Wide Range ◽  
Initial Soil ◽  
Rain Events ◽  
The Impact

Abstract. The Cévennes-Vivarais region in southern France is prone to high intensity and long lasting rainfalls that can lead to flash floods which are one of the most hazardous natural risks in Europe. The results of numerous studies show that besides rainfall depth and intensity and catchment characteristics such as topography, geology, land use and hydraulic routing, the catchment's initial soil moisture also impacts the hydrological response to rain events. The aim of this paper is to analyze the relationship between catchment mean initial soil moisture θ~ini and the hydrological response that is quantified using the event-based runoff coefficient ϕev in the two nested catchments of the Gazel (3.4 km2) and the Claduègne (43 km2). To this end, two research questions are addressed: (1) How heterogeneous are soil moisture patterns in space and time and do they correlate with land use? (2) How does soil moisture at the event onset affect the hydrological response? The estimation of soil moisture at catchment scale is hindered by high spatial and temporal variability. A sampling setup including 45 permanently installed frequency domain reflectancy probes that continuously measure volumetric soil moisture at three depths is applied. Additionally, on-alert measurements of soil moisture in the topsoil at ≈ 10 locations in each one of 11 plots are conducted. Thus, catchment mean soil moisture can be confidently assessed with a standard error of the mean of ≤ 1.7 vol% over a wide range of soil moisture conditions. ϕev is calculated from high-resolution discharge and precipitation data for several rain events with a cumulative precipitation Pcum ranging from less than 5 mm to more than 80 mm. Because of the high uncertainty of ϕev associated to the hydrograph separation method, ϕev is calculated with several methods, including graphical methods, digital filters and a tracer based method. The results indicate that the hydrological response depends on θ~ini : the seasonal as well as the within-event discharge dynamics follow that of soil moisture. During dry conditions ϕev is consistently close to zero, even for events with high and intense precipitation. Above a threshold of θ~ini = 34 vol% ϕev can reach values up to 0.99 but there is a high scatter. Some variability can be explained with a weak correlation of ϕev with Pcum and rain intensity, but a considerable part of the variability remains unexplained. It is concluded that threshold-based methods can be helpful to prevent overestimation of the hydrological response during dry catchment conditions. The impact of soil moisture on the hydrological response during wet catchment conditions, however, is still insufficiently understood and cannot be generalized based on the present results.

Initial soil moisture retrievals from the METOP-A Advanced Scatterometer (ASCAT)

2007 ◽  
Vol 34 (20) ◽  
Author(s):  
Zoltan Bartalis ◽  
Wolfgang Wagner ◽  
Vahid Naeimi ◽  
Stefan Hasenauer ◽  
Klaus Scipal ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Initial Soil Moisture ◽  
Initial Soil

Exploring the potential of soil moisture reanalysis data for improving the identification of regional landslide triggering thresholds

2021 ◽  
Author(s):  
Nunziarita Palazzolo ◽  
David J. Peres ◽  
Enrico Creaco ◽  
Antonino Cancelliere
Keyword(s):  
Soil Moisture ◽  
Rainfall Event ◽  
Rainfall Thresholds ◽  
Rainfall Duration ◽  
Soil Moisture Data ◽  
Initial Soil Moisture ◽  
Initial Soil ◽  
Different Depths ◽  
Moisture Conditions ◽  
Landslide Triggering

<p>Landslide triggering thresholds provide the rainfall conditions that are likely to trigger landslides, therefore their derivation is key for prediction purposes. Different variables can be considered for the identification of thresholds, which commonly are in the form of a power-law relationship linking rainfall event duration and intensity or cumulated event rainfall. The assessment of such rainfall thresholds generally neglects initial soil moisture conditions at each rainfall event, which are indeed a predisposing factor that can be crucial for the proper definition of the triggering scenario. Thus, more studies are needed to understand whether and the extent to which the integration of the initial soil moisture conditions with rainfall thresholds could improve the conventional precipitation-based approach. Although soil moisture data availability has hindered such type of studies, yet now this information is increasingly becoming available at the large scale, for instance as an output of meteorological reanalysis initiatives. In particular, in this study, we focus on the use of the ERA5-Land reanalysis soil moisture dataset. Climate reanalysis combines past observations with models in order to generate consistent time series and the ERA5-Land data actually provides the volume of water in soil layer at different depths and at global scale. Era5-Land project is, indeed, a global dataset at 9 km horizontal resolution in which atmospheric data are at an hourly scale from 1981 to present. Volumetric soil water data are available at four depths ranging from the surface level to 289 cm, namely 0-7 cm, 7-28 cm, 28-100 cm, and 100-289 cm. After collecting the rainfall and soil moisture data at the desired spatio-temporal resolution, together with the target data discriminating landslide and no-landslide events, we develop automatic triggering/non-triggering classifiers and test their performances via confusion matrix statistics. In particular, we compare the performances associated with the following set of precursors: a) event rainfall duration and depth (traditional approach), b) initial soil moisture at several soil depths, and c) event rainfall duration and depth and initial soil moisture at different depths. The approach is applied to the Oltrepò Pavese region (northern Italy), for which the historical observed landslides have been provided by the IFFI project (Italian landslides inventory). Results show that soil moisture may allow an improvement in the performances of the classifier, but that the quality of the landslide inventory is crucial.</p>

Soil Type, Soil Moisture, and Field Slope Influence the Horizontal Movement of Salmonella enterica and Citrobacter freundii from Floodwater through Soil

2016 ◽  
Vol 80 (1) ◽  
pp. 189-197 ◽  
Author(s):  
MARY THERESA CALLAHAN ◽  
SHIRLEY A. MICALLEF ◽  
ROBERT L. BUCHANAN
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Type ◽  
Soil Moisture Content ◽  
Clay Content ◽  
Horizontal Movement ◽  
Initial Soil Moisture ◽  
Salmonella Newport ◽  
Initial Soil ◽  
Rate Of Decline

ABSTRACT Pathogens in soil are readily mobilized by infiltrating water to travel downward through the soil. However, limited data are available on the horizontal movement of pathogens across a field. This study used a model system to evaluate the influence of soil type, initial soil moisture content, and field slope on the movement of Salmonella enterica serovar Newport across a horizontal plane of soil under flooding conditions. Three soil types of varying clay content were moistened to 40, 60, or 80% of their maximum water-holding capacities and flooded with water containing 6 log CFU/ml Salmonella Newport and Citrobacter freundii, the latter being evaluated as a potential surrogate for S. enterica in future field trials. A two-phase linear regression was used to analyze the microbial populations recovered from soil with increasing distance from the flood. This model reflected the presence of lag distances followed by a quantifiable linear decrease in the population of bacteria as a function of the distance from the site of flooding. The magnitude of the lag distance was significantly affected by the soil type, but this was not attributable to the soil clay content. The rate of the linear decline with distance from the flood zone was affected by soil type, initial soil moisture content, and soil incline. As the initial soil moisture content increased, the rate of decline in recovery decreased, indicating greater bacterial transport through soils. When flooding was simulated at the bottom of the soil incline, the rate of decline in recovery was much greater than when flooding was simulated at the top of the incline. There was no significant difference in recovery between Salmonella Newport and C. freundii, indicating that C. freundii may be a suitable surrogate for Salmonella Newport in future field studies.

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