Nam Song Diversion Dam info by Hobo Maps - Go to Hydropower Projects Page - - Home
The Nam Song Diversion project is owned by EDL GEN and has a 6 MW power station located on a diversion canal.
The Nam Song river is a rather short river that runs southward through Vang Vieng and joins the Nam Lik river west of Nam Ngum reservoir. The diversion channel now directs most of the flow into the upper area of Nam Ngum reservoir.
The project is located in Vang Vieng District of Vientiane Province, Lao PDR and has an installed capacity of 6 MW from 3 Kaplan turbines of 2 MW each which can generate 13.2 GWh of electricity annually. The energy generated is transmitted to the 22 kV EDL system.
Nam Song Diversion powerhouse image below at coordinates - 18°48'16.0"N 102°27'26.8"E (18.804452, 102.457448):
The project is a run-of-river style hydroelectric project without a reservoir. It has a 21 meter high weir dam that creates a head pond. A small power station generates electricity further down the diversion canal. From there the water flows under Highway 13 into the far northwest part of Nam Ngum Reservoir.
Nam Song Diversion weir/dam image below at coordinates - 18°47'55.4"N 102°25'37.9"E (18.798712, 102.427183)
Satellite image below shows the Nam Song river weir on upper left side while the powerhouse is upper center. The diversion canal continues on the right side until crossing underneath Highway 13 where the waters enter the upper part of Nam Ngum Reservoir.
The project was completed in two phases. The first phase which just diverted water into Nam Ngum reservoir began in 1993 and was finished in 1996 at a cost of US$ 17 million.
The second phase which added a power plant, switchyard and transmission system began in 2010 and was finished in Jan. 2012 at a cost of US$ 13.3 million. Opening ceremony for the second phase was held on 18 February 2013. was a main contractor for Phase two of the project.
Total cost for both phases came to about US$ 31.3 million. Phase 1 received major financing of US$ 17 million from Asian Development Bank (ADB). For the second phase, Export Import Bank of India loaned US$ 11 million and EDL contributed the remainder.
Nam Song Diversion project map below:
Nam Song Diversion view image below:
Nam Song power plant image below.
The catchment area for the project covers an area of 1,330 square kilometers.
Nam Song power plant control images below:
Nam Song generator images below:
Phase 2 image below:
Transmission line image below:
Nam Song Dam weir image below. A minimum flow of 2 cubic meters per second is continuously allowed to spill over the weir dam so the original Nam Song river channel always has a flow downstream of the weir.
Nam Song Diversion project statistics below:
Nam Song Diversion works summary below from 1997 ADB report after completion of the first phase.
The diversion scheme consists of :
(i) a 2.5 kilometer canal across the low ridge between the Nam Song valley and the Nam Ngum reservoir;
(ii) 3 regulating/control/drop structures along the canal;
(iii) a concrete and earthfill dam, 21 meters high, on the Nam Song to raise the headpond water level to that of the canal;
(iv) power supplies to the dam and gate control structure; and
(v) access roads to all the structures.
The diversion is designed for a maximum flow of 210 cubic meters per second with an estimated average flow of 65 cubic meters per second.
A minimum flow of 2 cubic meters per second is designed to be maintained on the existing riverbed past the Nam Song dam for downstream users. The Nam Ken river, a significant tributary, enters the Nam Song about 800 meters downstream of the dam.
Nam Song diversion shown in central area of basin map below:
Nam Song Diversion project location shown on middle left side of map below:
Access road to Nam Song Hydropower Plant starts from Highway 13 near the km 122 marker as shown below. The road is paved at first but not sure if the entire distance is paved.
Hin Heup substation in image below receives output from Nam Song Diversion power plant but is not otherwise related to the Nam Song project.
