Uncovering patterns of near-surface saturated hydraulic conductivity in an overland flow-controlled landscape

Geoderma ◽  
2013 ◽  
Vol 195-196 ◽  
pp. 1-11 ◽  
Author(s):  
Alexander Zimmermann ◽  
Dustin S. Schinn ◽  
Till Francke ◽  
Helmut Elsenbeer ◽  
Beate Zimmermann
2021 ◽  
Author(s):  
Sara Rabouli ◽  
Vivien Dubois ◽  
Marc Serre ◽  
Julien Gance ◽  
Hocine Henine ◽  
...  

<p>The soil is considered as a biological reactor or an outlet for treated domestic wastewater, respectively to reduce pollutant concentrations in the flows or because the surface hydraulic medium is too remote. In these cases, the saturated hydraulic conductivity of the soil is a key is a quantitative measure to assess whether the necessary infiltration capacity is available. To our knowledge, there is no satisfactory technique for evaluating the saturated hydraulic conductivity Ks of a heterogeneous soil (and its variability) at the scale of a parcel of soil. The aim of this study is to introduce a methodology that associates geophysical measurements and geotechnical in order to better described the near-surface saturated hydraulic conductivity Ks. Here we demonstrate here the interest of using a geostatistical approach, the BME "Bayesian Maximum Entropy", to obtain a 2D spatialization of Ks in heterogeneous soils. This tool opens up prospects for optimizing the sizing infiltration structures that receive treated wastewater. In our case, we have Electrical Resistivity Tomography (ERT) data (dense but with high uncertainty) and infiltration test data (reliable but sparse). The BME approach provides a flexible methodological framework to process these data. The advantage of BME is that it reduces to kriging as its linear limiting cases when only Gaussian data is used, but can also integrate data of other types as might be considered in future works. Here we use hard and Gaussian soft data to rigorously integrate the different data at hand (ERT, and Ks measurement) and their associated uncertainties. Based on statistical analysis, we compared the estimation performances of 3 methods: kriging interpolation of infiltration test data, the transformation of ERT data, and BME data fusion of geotechnical and geophysical data. We evaluated the 3 methods of estimation on simulated datasets and we then do a validation analysis using real field data. We find that BME data fusion of geotechnical and geophysical data provides better estimates of hydraulic conductivity than using geotechnical or geophysical data alone.</p>


2014 ◽  
Vol 18 (10) ◽  
pp. 4169-4183 ◽  
Author(s):  
T. G. Wilson ◽  
C. Cortis ◽  
N. Montaldo ◽  
J. D. Albertson

Abstract. There is increased interest in the interplay between vegetation conditions and overland flow generation. The literature is unclear on this relationship, and there is little quantitative guidance for modeling efforts. Therefore, experimental efforts are needed, and these call for a lightweight transportable plot-scale (>10 m2) rainfall simulator that can be deployed quickly and quickly redeployed over various vegetation cover conditions. Accordingly, a variable-intensity rainfall simulator and collection system was designed and tested in the laboratory and in the field. The system was tested with three configurations of common pressure washing nozzles producing rainfall intensities of 62, 43, and 32 mm h-1 with uniformity coefficients of 76, 65, and 62%, respectively, over a plot of 15.12 m2. Field tests were carried out on a grassy field with silt–loam soil in Orroli, Sardinia, in July and August 2010, and rainfall, soil moisture, and runoff data were collected. The two-term Philip infiltration model was used to find optimal values for the saturated hydraulic conductivity of the soil surface and bulk soil, soil water retention curve slope, and air entry suction head. Optimized hydraulic conductivity values were similar to both the measured final infiltration rate and literature values for saturated hydraulic conductivity. This inexpensive (less than USD 1000) rainfall simulator can therefore be used to identify field parameters needed for hydrologic modeling.


Soil Research ◽  
2012 ◽  
Vol 50 (4) ◽  
pp. 257 ◽  
Author(s):  
Shun Lei Peng ◽  
Jian Wu ◽  
Wen Hui You

Saturated hydraulic conductivity (Ks) can be used to indicate changes in soil hydrology resulting from vegetation succession. A constant-head permeameter was used to investigate differences in Ks at five soil depths (10, 20, 40, 60, and 80 cm) along a successional sequence of 155 years in evergreen broad-leaved forest at Tiantong National Forest Park, eastern China. The following six forest successional classes were studied: climax evergreen broad-leaved forest (CE), sub-climax evergreen broad-leaved forest (SE), evergreen broad-leaved mixed coniferous forest (MF), coniferous forest (CF), secondary shrub (SS), and abandoned land (AL). Surface Ks (the geometric mean of Ks at 10 and 20 cm soil depths) significantly increased from AL to CE but declined in CF. The surface Ks value under CE was higher than under other successional stages (CE 271 mm h–1, AL 58 mm h–1, SS 124 mm h–1, CF 90 mm h–1, MF 170 mm h–1, SE 231 mm h–1), and was 4.7 times greater than under AL, 2.2 times greater than under SS, and 3.0 times greater than under CF, but showed no significant difference from SE (P > 0.05). Vertical difference of Ks was detected up to a soil depth of 40 cm along forest successional series. Macroporosity was the main determining factor and played an important role in the process of Ks recovery. The likelihood of overland flow generation was inferred by comparing Ks at soil depths of 10, 20, 40, and 60 cm under the various successional stages at prevailing storm intensities. Overland flow was most likely to occur in the early successional stages. This study suggests that Ks could be restored to climax forest levels along forest successional series, but the recovery time could be as long as 95 years.


Water ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2383
Author(s):  
Hatma Suryatmojo ◽  
Ken’ichirou Kosugi

In tropical Indonesia, rainforests are managed by an intensive forest management system (IFMS). The IFMS has promoted selective logging for timber harvesting and intensive line planting to enrich the standing stock. The implementation of the IFMS has reduced the forest canopy cover, disturbed the surface soil, changed the soil hydraulic properties, and increased direct runoff and soil erosion. Investigation of the IFMS impact on soil hydraulic properties and the generation of surface runoff using a saturated hydraulic conductivity model is needed. Soil hydraulic properties were investigated on 11 plots, including one virgin forest plot and 10 plots at different operational periods of the IFMS. A two-dimensional saturated soil water flow simulation was applied to generate surface runoff from different periods of the IFMS. The main parameters of canopy cover, net rainfall, and saturated hydraulic conductivity were used in the simulations. A simulation scenario of a surface runoff hydrograph in different forest operations was used to analyze the river buffer effectiveness. The results showed that fundamental IFMS activities associated with mechanized selective logging and intensive line planting have reduced the soil hydraulic conductivity within the near-surface profile. The recovery time for near-surface Ks on non-skidder tracks was between 10 and 15 years, whereas on the skidder tracks it was more than 20 years. Forest disturbances have altered the typical surface hydrological pathways, thereby creating the conditions for more surface runoff on disturbed surfaces than on undisturbed surfaces. Maintaining the buffer area is an effective means to reduce the peak discharge and surface runoff in the stream channel.


2014 ◽  
Vol 11 (4) ◽  
pp. 4267-4310
Author(s):  
T. G. Wilson ◽  
C. Cortis ◽  
N. Montaldo ◽  
J. D. Albertson

Abstract. There is increased interest in the interplay between vegetation conditions and overland flow generation. The literature is unclear on this relationship and there is little quantitative guidance for modeling efforts. Therefore, experimental efforts are needed and these call for a lightweight transportable plot-scale (>10 m2) rainfall simulator that can be deployed quickly and quickly redeployed over various vegetation cover conditions. Accordingly, a variable intensity rainfall simulator and collection system was designed and tested in the laboratory and in the field. The system was tested with three configurations of common pressure washing nozzles producing rainfall intensities of 62, 43, and 32 mm h−1 with uniformity coefficients of 76, 65, and 62, respectively, over a plot of 15.12 m2. Field tests were carried out in on a grassy field with silt-loam soil in Orroli, Sardinia in July and August 2010, and rainfall, soil moisture, and runoff data were collected. The two-term Philip infiltration model was used to find optimal values for the saturated hydraulic conductivity of the soil surface and bulk soil, soil water retention curve slope, and air entry suction head. Optimized hydraulic conductivity values were comparable to both the measured final infiltration rate and literature values for saturated hydraulic conductivity. This inexpensive rainfall simulator can therefore be used to identify field parameters needed for hydrologic modeling.


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