Leakage monitoring : The experiment was conducted in wet sand with 12% water content for 35 minutes. After 15 minutes from the beginning of the test, a water leakage event was simulated around one of the nodes located at 55 cm from the sender. After the water leakage event , the receivers located behind 55 cm from the sender showed lower received signal strengths due to more attenuation caused by the increase in water content as shown in Figure 2(b). The wireless sensor node located at 95 cm lost the signal from the source due to high attenuation and no data was racorded on the node. With the decreased received signal information ,both the time of the occurrence and location of the event could be detected