Kiew Kho Ma Dam


         Ban Huai Sanao Village, Pong Don Sub-district, Chae Hom District, Lampang Province



Type Earth dam
Height 43.5 meters
Length 500 meters
Width 8 meters
Storage capacity 170 million cubic meters



Main river Wang River
Branch river Wang River
Rainwater catchment Area 1,275.00 square kilometers
Average rainfall all year 1,039.00 millimeters/year
Annual runoff 265.00 million cubic meters
River length from upstream to project site 150 kilometers
River channel slope at project site 1 : 1,000


Engineering Characteristics

         Uses water 163.80 million cubic meters.

Water storage levelReservoir capacity (million cubic meters)Reservoir area (rai)
Lowest +325.00 meters MSL 6.20 1,063
Normal +350.20 meters MSL 170.00 7,925
Highest +352.90 meters MSL 208.60 9,600


Project Dam and Building Features

 Main DamSaddle Dam
Type Zone Type Homogeneous Type
Crest elevation +355.50 meters MSL +355.50 meters MSL
Crest width 8.00 meters 6.00 meters
Crest length 500.00 meters 300.00 meters
Base width at deepest point 275.00 meters 102 meters
Upstream slope 1 : 2.5 and 1 : 3.0 1 : 3.0
Downstream slope 1 : 2.0 and 1 : 2.5 1 : 2.5



Service Spillway

Location right side of main dam
Type reinforced concrete building with dam crest
Type of radial gate installed on dam crest Radial Gate Spillway
Floodgate dimensions 12.50 x 7.00 meters
Number of floodgates 3 gates
Drainage channel width 42.50 meters
Building length (overall) 800 meters
Soil level (dam crest) of floodgate +346.50 meters MSL
Highest overflow level +352.90 meters MSL
Flood Surcharge 6.40 meters
Maximum drainage 1,209.00 cubic meters/second
Drainage rate of return period 1,000 years


River Outlet

Location right side of main dam
Pipe type steel pipe covered with reinforced concrete
Steel pipe length (main pipe) 205.00 meters
Diameter inside steel pipe 2.50 meters
Steel pipe thickness 18 millimeters
Building structure eco-friendly reinforced concrete
Building soil level 1: +325.000 meters MSL
level 2: +333.676 meters MSL
level 3: +341.176 meters MSL



Total capacity 5.5 MW
Number of units 3 units (2x2.5 MW and 1x0.5 MW)
Transmission system 22 kV
Average generated power per year 69.37 million kWh



  1. Generate power into the system around 50.657 million units per year
  2. Decrease the need to import fuel for power generation 12.66 million liters per year
  3. Reduce carbon dioxide emissions 28,398.75 tons per year which EGAT was able to develop into a Clean Development Mechanism (CDM) project
  4. Mitigate global warming


June 2018