scholarly journals Determination of Spatial and Temporal Variability of Soil Hydraulic Conductivity for Urban Runoff Modelling

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 941 ◽  
Author(s):  
Matej Radinja ◽  
Ines Vidmar ◽  
Nataša Atanasova ◽  
Matjaž Mikoš ◽  
Mojca Šraj
Keyword(s):  
Hydraulic Conductivity ◽  
Temporal Variability ◽  
Water Repellency ◽  
Infiltration Rate ◽  
Control Measures ◽  
Soil Conditions ◽  
Spatial And Temporal Variability ◽  
Soil Hydraulic Conductivity ◽  
Soil Hydraulic

Soil hydraulic conductivity has a direct influence on infiltration rate, which is of great importance for modelling and design of surface runoff and stormwater control measures. In this study, three measuring techniques for determination of soil hydraulic conductivity were compared in an urban catchment in Ljubljana, Slovenia. Double ring (DRI) and dual head infiltrometer (DHI) were applied to measure saturated hydraulic conductivity (Ks) and mini disk infiltrometer (MDI) was applied to measure unsaturated hydraulic conductivity (K), which was recalculated in Ks in order to compare the results. Results showed significant differences between investigated techniques, namely DHI showed 6.8 times higher values of Ks in comparison to DRI. On the other hand, Ks values obtained by MDI and DRI exhibited the lowest difference. MDI measurements in 12 locations of the small plot pointed to the spatial variability of K ranging between 73%–89% as well as to temporal variability within a single location of 27%–99%. Additionally, a reduction of K caused by the effect of drought-induced water repellency was observed. Moreover, results indicate that hydrological models could be enhanced using different scenarios by employing a range of K values based on soil conditions.

scholarly journals Assessing Water Infiltration and Soil Water Repellency in Brazilian Atlantic Forest Soils

2020 ◽  
Vol 10 (6) ◽  
pp. 1950 ◽  
Author(s):  
Sergio Esteban Lozano-Baez ◽  
Miguel Cooper ◽  
Silvio Frosini de Barros Ferraz ◽  
Ricardo Ribeiro Rodrigues ◽  
Laurent Lassabatere ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Water ◽  
Atlantic Forest ◽  
Water Repellency ◽  
Water Infiltration ◽  
Brazilian Atlantic Forest ◽  
Soil Water Repellency ◽  
Soil Hydraulic Conductivity ◽  
Soil Hydraulic ◽  
Remnant Forest

This study presents the results of the soil hydraulic characterization performed under three land covers, namely pasture, 9-year-old restored forest, and remnant forest, in the Brazilian Atlantic Forest. Two types of infiltration tests were performed, namely tension (Mini-Disk Infiltrometer, MDI) and ponding (Beerkan) tests. MDI and Beerkan tests provided complementary information, highlighting a clear increase of the hydraulic conductivity, especially at the remnant forest plots, when moving from near-saturated to saturated conditions. In addition, measuring the unsaturated soil hydraulic conductivity with different water pressure heads allowed the estimation of the macroscopic capillary length in the field. This approach, in conjunction with Beerkan measurements, allowed the design better estimates of the saturated soil hydraulic conductivity under challenging field conditions, such as soil water repellency (SWR). This research also reports, for the first time, evidence of SWR in the Atlantic Forest, which affected the early stage of the infiltration process with more frequency in the remnant forest.

Critical analysis of the field determination of soil hydraulic conductivity functions using the flux-gradient approach

1998 ◽  
Vol 48 (1-2) ◽  
pp. 81-89 ◽  
Author(s):  
K Reichardt ◽  
O Portezan ◽  
P.L Libardi ◽  
O.O.S Bacchi ◽  
S.O Moraes ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Critical Analysis ◽  
Soil Hydraulic Conductivity ◽  
Flux Gradient ◽  
Soil Hydraulic ◽  
Gradient Approach

The WormEx I Experiment: Effects of biopores and earthworm holes on soil hydraulic conductivity, sorptivity and macroscopic capillary length

2020 ◽  
Author(s):  
Dario Pezzotti ◽  
Marco Peli ◽  
Roberto Ranzi ◽  
Stefano Barontini
Keyword(s):  
Hydraulic Conductivity ◽  
Water Content ◽  
Soil Water ◽  
Soil Conditions ◽  
Pressure Potential ◽  
Capillary Length ◽  
Soil Hydraulic Conductivity ◽  
Adverse Conditions ◽  
Soil Hydraulic ◽  
Infiltration Tests

<p>The WormEx I Experiment was launched on 9 March 2016 to investigate the effects of biopores and earthworms holes on soil-water constitutive laws.<br>Particularly, changes in the soil hydraulic conductivity, in the soil sorptivity and in the macroscopic capillary length were evaluated in different soil conditions, by means of infiltrometric tests performed in a shallow anthropogenic soil of the Central Italian Alps (Cividate Camuno, Italy).<br>About 50 field infiltration tests were performed by means of a tension infiltrometer (TI) and by means of a small single ring infiltrometer, in view of applying the simplified BEST method (Beerkan Estimation of Soil Transfer parameters).<br>The worms presence was accounted for by counting worms' castings in 1 m<sup>2</sup> experimental plots, and it was considered a proxy of the biogenic activity.<br>Various meteorological conditions and various conditions of the presence of worms' castings were sampled during a period of three years.<br>Obtained results highlight how soil hydrological properties change depending on the biopores presence.</p><p>As a result, the hydraulic conductivity greatly increased in presence of soil biopores, both in ponding and in near-saturation conditions.<br>Conductivity at saturation increased on average by 45% (TI method), between great and small presence of earthworms' holes.<br>Considering soil conditions that stimulate the biological activity (e.g. the previous days precipitation and the great water content at the beginning of the infiltration tests), the conductivity at saturation increased more, i.e. by 85% (TI) and by 105% (BEST) on average.<br>The increase is even more relevant passing from adverse conditions (low castings number and small initial soil-water content) to optimal conditions (high castings number and great initial soil-water content).<br>In these cases average increments are more than 200% (TI).</p><p>Also the hydraulic conductivity of the nearly saturated soil, with pressure potential ranging between -5 cm and  0 cm, meaningfully increased in case of biopores presence.<br>The greatest (relative) increase of the soil hydraulic conductivity was observed in most of the cases at a pressure potential of -2 cm.</p><p>Sorptivity meaningfully increased from low to high wormholes number (45% at saturation) and from optimal to adverse conditions (114% at saturation).<br>As for the hydraulic conductivity, this increase was even greater nearby ponding conditions.<br>Field-tests results changed greatly depending on time and space: great standard deviations were observed for both hydraulic conductivity and sorptivity at all the values of pressure potential.</p><p>The macroscopic capillary length λ<sub>c</sub>, which provides concise information about the soil attitude to diffusion, determined by numerically evaluating the subtended area to the experimental hydraulic-conductivity curve, also evidenced the presence of earthworms' burrows, ranging from 16.9 mm to  11.6 mm in optimal and adverse conditions respectively.</p>

Assessing Water Infiltration and Soil Water Repellency in Brazilian Atlantic Forest Soils

2020 ◽  
Author(s):  
Sergio Esteban Lozano-Baez ◽  
Miguel Cooper ◽  
Silvio Frosini de Barros Ferraz ◽  
Ricardo Ribeiro Rodrigues ◽  
Mirko Castellini ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Water ◽  
Atlantic Forest ◽  
Water Repellency ◽  
Water Infiltration ◽  
Brazilian Atlantic Forest ◽  
Soil Water Repellency ◽  
Soil Hydraulic Conductivity ◽  
Soil Hydraulic ◽  
Remnant Forest

<p>This study presents the results of the soil hydraulic characterization performed under three land covers, namely pasture, 9-year-old restored forest, and remnant forest, in the Brazilian Atlantic Forest. Two types of infiltration tests were performed, namely tension (Mini-Disk Infiltrometer, MDI) and ponding (Beerkan) tests. MDI and Beerkan tests provided a complementary information, highlighting a clear increase of the hydraulic conductivity, especially at the remnant forest plots, when moving from near-saturated to saturated conditions. In addition, measuring the unsaturated soil hydraulic conductivity with different water pressure heads also allowed to estimate the macroscopic capillary length in the field. This approach, in conjunction with Beerkan measurements, allowed to generate better estimates of the saturated soil hydraulic conductivity under challenging field conditions, such as soil water repellency (SWR). This research also reports for the first time evidence of SWR in the Atlantic Forest, which affected the early stage of the infiltration process with more frequency in the remnant forest.</p>

scholarly journals Analysis of Land Use Change and Its Impact on the Hydrology of Kakia and Esamburmbur Sub-Watersheds of Narok County, Kenya

Hydrology ◽  
2019 ◽  
Vol 6 (4) ◽  
pp. 86
Author(s):  
Nzitonda Marie Mireille ◽  
Hosea M. Mwangi ◽  
John K. Mwangi ◽  
John Mwangi Gathenya
Keyword(s):  
Land Use ◽  
Hydraulic Conductivity ◽  
Land Use Change ◽  
Land Cover ◽  
Land Cover Change ◽  
Flood Risk ◽  
Infiltration Rate ◽  
Land Use Land Cover ◽  
Soil Hydraulic Conductivity ◽  
Soil Hydraulic

Narok town is one of the places in Kenya which experience catastrophic floods. Many lives have been lost and valuable property destroyed in recent years. Change in land use/land cover upstream of the town area may have contributed significantly to the severity and frequency of flooding events. Runoff, which contributes to floods in Narok town, comes from Kakia and Esamburmbur sub-catchments of Enkare Narok watershed. The objective of this study was to assess the impact of land use/land cover change on the hydrology of Kakia and Esamburmbur sub-watersheds. To detect land use/land cover change, Landsat satellite images from 1985 to 2019 were used. Using supervised classification in Erdas Imagine 2014, land use of the study area was classified into four classes, i.e., forest, rangeland, agriculture and built-up areas. Five land use maps (1985, 1995, 2000, 2010, and 2019) were developed and used to perform land use change analysis. There was rampart conversion of forest to other land uses. Between 1985 and 2019, the forest and rangeland declined by 40.3% and 25.6% of the study area, respectively, while agriculture and built-up areas increased by 55.2% and 10.6% of the study area respectively. Analysis of soil hydrological properties indicate that the infiltration rate and soil hydraulic conductivity were greatest in forest than in other land use types. The basic infiltration rate in forest land was 89.1 cm/h while in rangeland and agricultural land, it was 7.9 cm/h and 15 cm/h respectively. At the top-soil layer, average soil hydraulic conductivity under forest was 46.3 cm/h, under rangeland, 2.6 cm/h and under agriculture, 4.9 cm/h. The low hydraulic conductivity in rangeland and agriculture was attributed to compaction by farm machinery (tractors) and livestock respectively. An interesting observation was made in rangelands where the top layer (0–20 cm) had a higher bulk density and a lower hydraulic conductivity as compared to the next deeper layer (20–40 cm). This was attributed to the combined impact of compaction and localised pressure by hooves of livestock which only have an impact on the top layer. The findings of this study show that land use has a major impact on soil hydrological properties and imply that the observed land use changes negatively affected the soil hydrological properties of the watershed. The decreased infiltration in the increasing areas of degraded land (mainly agriculture and rangeland) and increase in built-up area in Narok town are the possible causes of the increased flood risk in Narok town. It is recommended that flood risk management strategies in Narok town include watershed management to enhance water infiltration.

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