evaluation of simplified falling head (sfh) method for measuring saturated hydraulic conductivity

abstract determining saturated hydraulic conductivity (ks) is one of the important soil characteristics that its estimation is important in soil and water studies. there are several methods for estimating ks in unsaturated conditions. these methods include the inversed-auger-hole method, the double-ring infiltrometer and the single-ring pressure infiltrometer. the measurement of ks by these methods requires large volumes of water and long period of time. the simplified falling head (sfh) technique is for rapid determination of ks, using small volumes of water and easily transportable equipments. the sfh technique appears hopeful and suitable for detailed and repeated sampling, also, over large areas. in this study, ks was measured by sfh method, double-ring and single-ring pressure infiltrometers for evaluating sfh method. results showed that in a loam soil, the sfh method estimate higher values for ks, compared with the double-ring and the single-ring pressure infiltrometers (respectively 9.6% and 18.5%). statistical analysis of the results of above methods showed that there is no significant difference between ks values (p<0.05). results of this study showed that the sfh technique yielded reliable ks values in a relatively short period of time without the need for extensive instrumentation or analytical methodology. so, it can be recomended as a suitable method in loam soils.