Hydraulic Conductivity of Soil Using Guelph Permeameter

The hydraulic conductivity (Ks) of soils is an important soil parameter that is essentially required for various fields of civil engineering where there is interaction between the soil and water. Its accurate determination is important in order to address various issues related with soil and water interaction in various fields of Civil engineering. It can be resoluted either by direct method (In situ or laboratory method) or by indirect method in which it is estimated by using some other properties of soil. Both field and laboratory procedures are difficult, cumbersome, time-consuming and expensive. In addition, the results may not be accurate due to spatial and temporal variability in soil physical and hydraulic properties. This has led to the development and general use of indirect methods that estimated K from more easily, widely available, routinely measured basic soil properties. The objective of this study is to develop empirical relation between saturated hydraulic conductivity and particle size distribution data by using regression analysis.

This section gives the overview of the study conducted on hydraulic conductivity by other researchers. Boadu (2000) Developed a regression model to estimate saturated hydraulic conductivity of compacted soil by using grain size distribution data wherein author has considered fractal dimensions and lack of predictability of the distributions, as well as porosity, soil density, and fines content the predictive capability of the model is in worthy agreement with the measured value of hydraulic conductivity. Holden and Burt (2003) have carried out experimental work to assess the variability of hydraulic conductivity of peat and they found that compressibility of soil generally decline with depth and also vary significantly between sampling sites. Chen et al. (2009) performed study of various factors on hydraulic conductivity such as land use

depth bulk density was increased and hydraulic conductivity decreased i.e. 2.9cm/min in upper 15 cm to 0.8cm/min in the 30 cm below in the Dongija (DJ) mountains. Forest soils were found to have the lowest average bulk density; pasture and cultivated soils as expected have higher densities average root volume in case of forest area is 29.5% and that in bare land is 5.1% measured value of KS at depth of 30 cm are 0.01, 0.6 and 0.8cm/min in the bare soil, agricultural and forest areas respectively. Wei Hu et al. (2009) carried out the study for understanding the effect of land usage and land cover on hydraulic conductivity and they found transformations in the magnitude of diminution in hydraulic conductivity existed for the four land uses. The numerical value of KS cannot be the largest or smallest for all the measurement sets. This may also reflect that the land use effect was time-dependent. Xi Chen et al. (2010) investigated the effect of vegetation cover on hydraulic permeability and found that the saturated hydraulic conductivity for the surface soil are very large as compared to those of deep soil for the soil under consideration saturated hydraulic conductivity depend on type of vegetation , age of vegetation and soil density. i.e. for forest its value is quite large due to large amount of roots and humus. To understand the effect of sloping terrain on the hydraulic conductivity. Majeedraoof et al. (2011) carried out study in the Gonbad research station, Hamadan, Iran. For study purpose four different slope from flat to 400 were selected and they found that there is diminution in the hydraulic conductivity with slope gradient Duan et al. (2012) carried out investigation to check the trustworthiness of the models proposed by Campbell, Smetten and Bristow and Sexton et al. compute saturated hydraulic conductivity in Texas soil with grass. They found that these models failed to predict the true representative value of saturated hydraulic conductivity if the constants and coefficients proposed by them were used directly without doing any modification to account for type of vegetation. The Saxton et al. and Campbell models were found to be more robust than the Smetten and Bristow model because the former two models contain two independent variables rather than the one included in the Smetten and Bristow model. Kameníčková et al. (2012) studied the impact of different cultivation treatment on hydraulic conductivity of loamy soil in Horqin. The KS value increased approximately six times for reduced cultivation and more than three times for conventional cultivation. conductivity of compacted clayey soil. They found that Kozenycarman equation can envisage the hydraulic conductivity of compressed clayey soil very close to the actual value of hydraulic conductivity.

1. In situ hydraulic conductivity by using Guelph Permeameter and to study its spatial variation, 2. Devise a model to determine hydraulic conductivity from simple index properties of soil. 3.1 Practical Relevance

In agriculture, ecology, hydrology, global change, and related sciences, there is a pressing need for improved instrumentation to augment the general understanding of water flow, nutrient/chemical transport, and heat transport processes in rooting zones, the vadose zone, and ground water Seasonal transitions in arid climates control the form and mobility of nitrogen and can in turn impact terrestrial and aquatic ecology. Soil hydraulic properties are key to quantitatively describing soil water flow and chemical transport. The hydraulic conductivity KS of soils is of great importance in relation to some geotechnical problems, including the determination of seepage losses, settlement computations, and stability analyses. The development, management, and protection of ground-water resources also demand reliable estimates of hydraulic conductivity. Accurate estimation of streambed vertical hydraulic conductivity (KS) is of great importance in the analysis of water quantity exchange and solute transfer between a stream and its sediments. Modelling of water transport and waste contaminant migration through soil, management of soil organic matter and management of water resources.

Following agencies will get benefitted from this  Agriculture

• Irrigation

• Environment and ecology

• Water resource management etc.

Saturated hydraulic conductivity of soil were measured in the field by using Guelph Permeameter at a depth of 15cm, 30cm, and 45cm; and soil samples were collected from the site at these depth. Index properties of the soil samples collected from field were determined in the laboratory. Empirical relation between the saturated hydraulic conductivity and index properties measured in the laboratory were developed by using regression analysis.

Figure 5.1 Guelph Permeameter Depth operation may rise by 80 cm. The maximum practical operating depth is 315 cm. 5.2 Determination of Field Hydraulic Conductivity of Soil Field hydraulic conductivity (permeability) of soil (Ks) can be determined by any of following method

Saturated hydraulic conductivity by using one head method can be found by using an equation as given below

Or

NOTE: or , depending on whether the combine reservoir was used (X) or inner reservoir was used (Y)

Saturated hydraulic conductivity by using two head method can be found by using an equation as given below. ) Where,

inner reservoir was used (Y)

In this project, the in-situ hydraulic conductivity is estimated by using Guelph Permeameter and the soil sample is collected from field to carry out laboratory tests such as Grain Size Analysis, Liquid Limit, Plastic Limit, and Shrinkage Limit.

7. CONCULSION

In this we projected the in-situ hydraulic conductivity of soil by using Guelph Permeameter and the soil is collected from field and laboratory test are carried out such as Grain Size Analysis, Liquid Limit, Plastic Limit, Shrinkage Limit. In this study described equations to estimate Ks, saturated hydraulic conductivity, from D10, D20, D30, D40, D50, and D60 data. The results showed approximately success in predicting hydraulic conductivity from particle diameters data.

In this project only grain size record were used to correlate permeability with the various % finer sizes such as D10, D20, D30, D40, D50, and D60. Other index properties can be correlated with the permeability such as liquid limit, plastic limit, shrinkage limit, mineralogical composition of soil, organic content, cation exchange capacity, density of soil etc.

B. P. Mohanty, R. S. Kanwar, and C. J. Everts (1994) ,‖ Comparison Of Saturated Hydraulic Conductivity Measurement Methods For A Glacial-Till Soil‖ Soil Sci. Soc. Am. J. 58 pp. 672-677. Chen , Zhicai Zhang , Xunhong Chen and Pen Shi (2009),” The Impact Of Land Use And Land Cover Changes On Soil Moisture And Hydraulic Conductivity Along The Karst Hillslope Of Southwest China” Environmental Earth Sci. pp. :811–820. Chen, Qinbo Cheng & Zhicai Zhang (2010),‖Measurement Of Soil Hydraulic Conductivity In Relation To Vegetation‖ Bhs Third International Symposium , Managing Consequence Of A Changing Global Environment, Newcastle pp.1-4. Emmanouil Steiakakis, Christos Gamvroudis and Georgios Alevizos (2012),‖ Kozeny-Carman Equation and Hydraulic Conductivity of Fred Kofi Boadu (2000),‖Hydraulic Conductivity of Soils from Grain-Size Distribution: New Models” J. Geotech. Geoenviron. Eng. 2000.pp. 126:739-746. I. Kameníčková, L. Larišová, A. Stoklásková, A. (2012),” The Impact Of Different Tillage Treatments On Hydraulic Conductivity Of Loamy Soil‖ Acta Universitatis Agriculturae Et SilviculturaeMendelianaeBrunensis pp.. 109-114. J. Holden1 and T.P. Burt (2003),”Variability of Hydraulic Conductivity in Upland Blanket Peat.‖ Hydrological Processes, 17 (6). pp. 1227-1237. M. Bonsu & B. A. Masopeh (1996),‖ Saturated Hydraulic Conductivity Values Of Some Forest Soils Of Ghana Determined By A ,Simple Method‖ I Ghana Jnl agric. Sci. 29, pp.75-80. R. K. Gupta , R.P. Rudra , W.T. Dickinson & G.J. Wall (1994),‖ Spatial And Seasonal Variations In Hydraulic Conductivity In Relation To Four Determination Techniques‖, Canadian Water Resources Journal pp.103-113. Runbin Duan; Clifford B. Fedler, and John Borrelli (2012),‖ Comparison Of Methods To Estimate Saturated Hydraulic Conductivity In Texas Soils With Grass‖ Journal Of Irrigation And Drainage Engineering pp.322-327. Wei Hu; Ming An Shao; QuanJiu Wang; Jun Fan; Klaus Reichardt (2009),” Temporal Changes Of Soil Hydraulic Properties Under Different Land Uses” Geoderma 149 (2009) pp..355–366.

Assistant Professor, Civil Engineering Department, JSPM‘s ICOER, Wagholi, Pune, Maharashtra, India