Geophysical Self-Potential Investigation to Detect Buried Water Supply Pipe Location in Kirkuk City-Northern Iraq

The newly established Seikanian suburban area is located about 5 km north of Kirkuk City. The area has a civil engineering problem concerning the unknown location of the water supply buried pipe in a road which might destructed during excavation works for maintenance operations. The geophysical surface self-potential method is chosen to find the pipe's location and depth. For acquiring data grid self-potential 20 and 22 points measurements were taken around the suspected location of the pipe within non-streaming water and streaming water in the pipe conditions respectively. Additional two survey lines of gradient configuration of 28 m length away of 3.5 m from the suspected buried pipeline carried out in the two conditions also. The grid self-potential points are rendered into observed, regional, and residual contour maps using surfer software 8. The interpreted self-potential gridded points in non-streaming water pipe conditions yielded positive anomalies in the observed map but the streaming water produced dominantly negative anomalies map. The residual self-potential maps in the two conditions showed positive and negative anomalies, all anomalies in the self-potential maps were spread along the center line of the maps where the suspected buried water supply pipe is extended, the residual maps showed it more clearly. To constrain the location of the buried water supply pipe second horizontal derivative technique upon the residual self-potential maps was applied and the constructed maps revealed accurately the anomalies aroused from the buried pipe spread over the center line. The gradient surveyed line profiles indicated that the self-potential signals submit to potential field theory formulations. The curve anomaly analysis of the survey line across the suspected buried pipe in the streaming water condition determined the depth of the buried pipe as 1.4 m.