Experimental and numerical investigation of the effects of muddy water on seepage reduction in earthen channels and dry zone of qanat

The ancient Iranians have used the underground water resources by excavating Qanats. If the Qanat is excavated in soils with high permeability coefficient, seepage in dry zone is the determinant part. One of the methods which is used for reduction of water-loss in dry zones is getting the water muddy. This study is about the investigation of the effects of muddy water on seepage reduction in trapezoid earthen channels which has the most resemblance to dry zones of qanats. In order to achieve this purpose an earthen channel with determined characteristics was excavated. In two stages fresh water and muddy water are conveyed into the channel and finally seepage was measured by using pondage test. The results have revealed that: 1- With moving the muddy water in a small period of time with forming sedimentary layer the seepage can be reduced more than forty-six percent (46%). 2- Numerical analysis indicated that the most significant factor in seepage reduction is sedimentary layer. 3- The achieved results from investigation showed in both conditions the Bouwer method indicates good correspondence with experimental results.