The Pong River or Lam Nam Pong is the only main watercourse flowing past this project.  It originates in the Petchaboon mountain range and froms the boundary line between Sibunruang  and Nonsang districts of Nongbualamphu and Sichomphu and Phuwieng District of Khon Kean Province before aiming into the Ubonratana Reservoir.  After this point, Flows thru the Nong Wai Operation and Maintenance project and finally joins the Chi River at the The Phra Sub-District, Muang District, Khon Kean Province. 



          The project area is influenced by the Southwest monsoon originating in the Indian Ocean with average annual rainfall of 1,198.4 mm.