It is the technical review study, survey and detailed design of diversion tunnel, beginning from the Mae Ngat Sombunchon, to augment inflow in Mae Kuang Udomthara Dam. The project components comprise diversion tunnel with a length of approximately 22 km, a diameter of 5 m with the maximum discharge capacity of 26 m3/sec, and an annual diversion capacity of 43.91 MCM.