HEC

Project location:Ngan Truoi river - Vu Quang district, Ha Tinh province

Construction time:2009 - 2014

Commencement time:14/06/2009

Project manager:Vu Phuong Minh

Major technical parameters:- Work grade: II

- Normal water level (NWL): 52.00 m

- Design maximum water level (DMWL) (P=0.5%): 54.56 m

- Check maximum water level (CMWL) (P=0.1%): 55.52 m

- Dead water level: 25 m

- Total storage capacity: 932.70 million m³

- Effective storage capacity: 704.00 million m³

- Flood control storage capacity: 157.00 million m³

- Dead storage capacity: 71.70 million m³

- Reservoir surface area at NWL: 43.10 km²

- Reservoir surface area at DMWL: 45.10 km²

- Reservoir surface area at CMWL: 46.70 km²

Scale and structure of project works

Project tasks

a. Completing irrigation system to supply water to:

- Exploitation of Thach Khe iron mine with discharge Q=6.0 m³/s and other industrial zones

- Irrigation of 32,585 ha of cultivated land

- 5,991 ha of aquaculture (fresh water: 3,500 ha and brackish water: 2,491ha)

b. Power generation N = 15 MW

c. Other industries and domestic uses; flood control and improvement of downstream ecological environment (with Q=4.0 m³/s); tourism development.

+ Main dam:

-Type: Zoned rock and earth dam

- Dam crest elevation: 57.8 m

Elevation of parapet crest: 59,0 m

Crest length: 342,0 m

Crest width: 12 m

- Hmax = 53.90 m

- Upstream slope ratio (m) : 3.0; 3.5; 4.0 and 2.0

Upstream berm elevation: 44.0 m and 29.0 m

Width of upstream berm: 5.0 m

Upstream slope protection: reinforced concrete

- Downstream slope ratio (m): 2.5; 3.0; 3.5 and 2.0

Downstream berm elevation: 44.0 m and 29.0 m

Width of downstream berm: 5.0 m

Downstream slope protection: grass planting and hand placed riprap

- Upstream and downstream toe drain: rockfill

Crest elevation: 19.0 m and 16.5 m, respectively

Crest width: 5.0 m

Upstreamand downstream slope ratios: 2.0

- Foundation seepage treatment: cement mortar grouting

+ Auxiliarydam:

-Type: Zoned earth and rock dam

- Dam crest elevation: 57.8 m

Parapet crest elevation: 59.0 m

Dam crest length: 222.0 m

Dam crest width: 8.0 m

- Hmax = 24.3 m

- Upstream slope ratio (m) : 2.75; 3.0

Upstream berm elevation: 44.0 m

Upstream berm width: 5.0 m

Upstream slope protection: reinforced concrete

- Downstream slope ratio (m): 2.5

Downstream slope protection: Grass planting

+ Spillway

-Type: Ophiserov spillway, bottom energy dissipator

- Check relief discharge p=0.1%: 2,237.0 m³/s

Design relief discharge p=0.5%: 1,937.0 m³/s

- Width of spillway: 40.0 m

- Spillway sill elevation: 45.0 m

- Gate type: Steel, segment gate, operated by hydraulic cylinder

n x (BxH) : 05 x (8x7)

- Elevation of energy dissipator basin bottom: 36.0 m

Length of energy dissipator basin: 36.0 m

Width of energy dissipator basin: 53,0 m

- Apron: Rectangle section

Length: 60.0 m

Width: 53.0 m

- Canal behind spillway: Trapezoidal section

Length: 1,000.0 m

Bottom width: 53.0 m

Slope ratio: 1.5

- Connection to the canal: extension of Khe Tri

+ Intake No.1:

- Operation regime: Pressure

- In construction diversion stage:

Maximum diversion discharge: 610.0 m³/s

Elevation of tunnel inlet: 10.0 m

Length of tunnel: 286.5m

Tunnel diameter: 7.0 m

- In exploitation management stage:

Design irrigation discharge: 56.8 m³/s

Environment flow discharge: 4.0 m³/s

Elevation of inlet: 19.0 m

nx(BxH) of gate: 02 x (2.6x4.0)

Length of penstock: 320.0 m

Diameter of penstock: 4.0 m

Diameter of inspection gallery: 7.0 m

Diameter of conical valve at downstream of penstock: 3.0 m

+ Powerhouse:

- Type:Powerhouse behind dam

- Installed capacity: 15 MW

- Number of unit: 03

- Operation regime: Generation according to irrigation

+ Intake No.1:

- Operation regime: Pressure

- Designirrigation discharge: 8.86 m³/s

- Elevationof inlet: 20.00 m

- Tunnel diameter: 2.0m

- Length oftunnel: 104.5m

- Operation gate: Conical valve

+ Newly constructed Khe Tri bridge:

- Number of span x length of one span (m): 03 x 33.0 = 99.0

- Bridge dimension: 9.0 m