sange siyah dam is located two kilometers down the kabod khani village. the environ of ghorrve city in kurdestan province. this is an clay core dam. in this dam instrumentation is performed in three section and consist of electrical piezometers, total pressure cells, settlement cells and so on. the main objective of instrumentation is to control the behavior of dam body and foundation, end else to control the accuracy of the assumption and subsequently accessing or proper assumptions for designing in the future. along this, during the building of sange siyah dam, instruments are calibrated and tested precisely and then installed with a full control in order to give a documentary about of information. the result of instrumentation has studied in two periods. these are construction and first impounding. in these periods the results are precisely and regularity recorded and after each reading, the essential controls are performed in order to reach enough confidence from the results and incorrect results are omitted. in the next stage, a finite element analysis is performed using the design parameters of soil on the highest section of the dam. the given results from the specific points that are the place for installing the instrumentations, are compared to the measured ones. in this stage a noticeable difference has observed between the calculated data and measured. thus the mentioned difference has dramatically decreased using the back analysis and also changing some of the soil parameters.