Khao Khen (เขาเขน) belongs to Plai Phraya District, Krabi. The Land Development Department reservoir inventory locates Huai Sak reservoir within this tambon. Original district field research identifies Khao Thong in Khao Khen as the source area of Khlong Phan Ton, which joins Khlong I Pan at Pak Nam in neighbouring Plai Phraya tambon. This distinguishes the upstream administrative area from the downstream village and from a reservoir point alone.
For a reservoir or agricultural appointment, use the actual access road and local host and check whether entry is permitted. Do not route to the downstream Pak Nam village when the destination is in Khao Khen. The administrative centre is separate from the reservoir entrance or authority premises.