2. Comparison :
Upgrading the dam (ongoing) v/s Building a new dam ( reconstruction )
Almost no impact on the local society. Necessity to reconstruct the local
society.
No Substitute roads reconstruction. Substitute roads reconstruction.
Environmental assessment is not
required.
Environmental assessment is
required.
Almost no impact on animals and
plant.
Necessity to mitigate impacts on
animal and plant.
3. MILT:
Ministry of Land, Infrastructure, Transport and
Tourism.
MLIT, is a ministry of the Japanese Govt. It is responsible for one-third of all the laws and
orders in Japan, and is the largest Japanese ministry in terms of employees, as well as the
second-largest executive agency of the Japanese government after the Ministry of
Defense.
MLIT executes comprehensive water management -
Planning
Coordinating
Implementing
Accumulating
4. Technologies to upgrade dams under
operation. :
1. Technologies to increase reservoir volume.
- Raising the dam body.
- Constructing a new dam just downstream from the operating dam without stream
diversion.
- Under water structural engineering work to construct in deep reservoir.
New Katsurazawa Dam in Hokkaido Kasabori Dam in Niigata
5. 2.Technology to increase discharge capacity.
- Constructing additional crest gate.
- Drilling the existing dam body from downstream.
- Constructing new spillways.
- Upgrading existing spillways.
Nagayasuguchi Dam in Tokushima
7. 3. Technology to improve structural stability.
- Improving an existing dam’s structure stability to resist earthquakes damage.
- Controlling seepage through dam bodies or their foundations.
- Improving structural stability of downstream.
- Inspecting structural stability to resist earthquake.
Tsuruda Dam in Kagoshima
8. 4.Technologies to improve operation.
- Maximizing its functions through coordination with several other dams.
- Implementing flexible operation well timed with the flood discharge.
- Converting to a new system while continuing operation.
- Construction or upgrading power plants.
5. Technologies to improve operation.
- Controlling sediment by bypass tunnels.
- Excavating and transporting sediment.
- Constructing a check dam to control sediment.
- Combining several sediment removal methods.
12. Conclusion:
• Upgrading dam is more reasonable and short-term.
• In comparison of building a new dam, upgradation is more
ecological.
• With the help of latest technology available, it requires less
manpower and less time for the work.
• It improves the serviceability of the existing dam after the
upgradation process.
• It increases the capacity of the energy production of dam.
Crest gate : Crest Gates are bottom hinged gates used where precise water level control is needed. They are typically hydraulically operated to allow for
opening during power outages in flood events.