Introducing and applying a two-dimensional electrical tomography method in detection of water movement and evaluating the effects of watershed management measures, case study: Vardij Catchment

The objective of this paper is introducing and applying a two-dimensional electrical tomography method in detection of water movement and evaluating the effects of watershed management measures. For these, four Dipole–Dipole profiles were designed operated and the data were recorded. These profiles included; profile A in the east-west direction, profile B and C in the north- south on the right bank upstream and downstream of the dam site and the D and E profiles, perpendicular to the river, on the right bank of the river valley. The RES2DINV software was used for two dimensional modeling. The results checked and calibrated using geological survey. Two water leakage path of a buried river channels and other stalagmites along the right bank of the river were detected. Results from profiles A indicated that fault damage zone North-South and seepage from the right abutment. The recorded resistivity of dam embankment was high; so the clay, which is used for construction of dam, is dry and shows a stable condition. The profile B was recorded at the distance of 50 meters from dam axis. A zone of low resistivity (with a dimension of 20*15 meters) was detected. This zone represents a pore space containing a high percentage of recharged water. The stored water flow slowly into other fracture zones down gradient along the watercourse. The D profile indicates the presence of buried river is the path that hydraulic gradient and direction with corresponding points A and B is consistent in the profiles. In conclusion, application of a two-dimensional electrical tomography method showed promise as a low cost and relatively quick methodology in evaluation of water movement in catchments. All in all, the effectiveness of the implemented watershed management activities was quantitatively approved by applying the aforesaid technique.