The Lower Xepain HHP is expected to locate on Nam Xepian river at location of HinLat village, Sanamsai district Sekong province. Dam sitewill be constructed at location where is about 40 Km from Attapeu provincial centerto the west and about 80 Km  far from PaKse District, Champasack province.Normal water level is 102 m and dead water level  is 101m. It is geographicalcoordinates are within: 14°44'56" Northern Latitude and 106°27'04" longitude

Nam Pagnou river is the 1st  graded branch on the right bank of Sekaman rivre and is the 2nd graded branch of Sekong river. It  is expected to locate on Nam PaGnou river in the vicinity of Dakchung District, Sekong province. Dam site will beconstructed at location where is about 7 Km far from Vietnam- Laos border into the west, 65 Km from Sekong Province into the northeast by Air line or about 100 Km in the route. And 20 Km far from Sekaman 3 Damsite on the upstream side by waterway.It is geographical coordinates are within: 15°32'12" Northern Latitude and 107°18'26" longitude The catchment area of Nam Pagnou  at dam site is 446.5 Km2. Normal water level is 1064 m and dead water level  is 1053 m. Area of reservoir surface confirming to NWL is 2.53  Km2.