OChum Hydropower Project

Project location: Ochum river - Retanakiri - Cambodia

Construction time: 1991-1993

Project manager: Phan Nhu Hai

Project tasks: Supplying power for Ochum and Ban Lung towns in Retanakiri province.

Major technical parameters:

Headworks grade: III (QPVN-08-76)

Basin area :

- To the reservoir: 23.1 km²

- To the weir: 44.7 km²

Cascade exploitation is as follows:

- Yearly reservoir at upstream of Ochum 1 waterfall, a canal of 900m long connected with Ochum 1 hydropower plant.

- Construction of weir and Ochum 2 hydropower plant.

Ochum hydropower project was carried out by 3 companies:

Investigation and design: Hydraulic Design and Investigation Company No.1 (now HEC)

Construction: Hydraulic Union No.4

Equipment: Dumont (French)

Scale and structure of project works:

OChum 1 headworks group:

- Main dam: homogeneous earth dam, dam length: 800m, Hmax=20m

- Ungated, surface spillway, B=30m, Qmax=78m³/s.

- Dam crest elevation: +295.0m

- Maximum water level: +293m

- Normal water level: +291.5 m

- Dead water level: +279.0m

- Total storage capacity: 12.9 million m³

- Effective storage capacity: 12.63 million m³

- Hydropower plant:

. Number of unit: 1

. Hmax: 22.07 m

. Hmin: 21.59 m

. Hcp: 28.83 m

. Q_design: 1.7 m³/s

. N_installed: 300 kw

Ochum 2 headworks group:

Weir consists of 2 parts:

Non-overflow part:: earthfill, length: 107.5 m; height: 10m.

Overflow part:: concrete, width B = 20m, height: 6m

Maximum water level: 257.65m

Normal water level: +254.0m

Dead water level: +252.0m

Hydropower plant: width: 7m, length: 25.2m

Number of unit: 2

Hmax: 34.26m

Hmin: 30.96m

Design head (H_design): 32.50m

Design discharge (Qtk): 3,76m3/s

Design capacity (N_design): 1000 kw

Average power output (Eo): 4.395 million kwh