Review of Some Methods of Determining in-Situ Saturated Hydraulic Conductivity of Soil

摘要

In-situ determination of K is important especially when the physical features of the soil system in question is to be characterized as accurately as possible. It gives more reliable values because there is minimal disturbance of the soil. It is more representative of the physical reality than the other methods. The objective of this study is therefore to review some of the in-situ methods of determining permeability, K of a soil, stating the conditions, advantages and disadvantages of each of the methods, thereby helping in proper selection of in-situ method to be adopted for a given soil, land terrain and type of aquifer. There are various methods of determining Saturated Hydraulic Conductivity, K of a soil. Application of each of the methods varies depending on the characteristics of the soil such as land terrain, soil water table and type of aquifer present. In this paper, nine in-situ methods, which include auger hole, two types of well pumping tests, piezometer, two well, tube, four well, tracer test, point dilution and cone permeameter, as well as thirteen types and fifteen formulae were reviewed. The advantages and disadvantages as well as conditions for use of each of the nine in-situ methods were stated. Out of the nine methods studied, the non-equilibrium condition for determination of R for wells penetrating a confined aquifer is found to be the most reliable. It is obvious that cone permeameter is the fastest and simplest of measuring K at different depths in a single push without the removal of soil or water from the hole, K is automatically measured within 10 minutes as the device’s probe is pushed into the desired depth in the ground. In terms of reliability, well pumping test of the non-equilibrium type is the most reliable and produces accurate results. Every other method is more or less related to each other and gives acceptable values of K.