The MLIT will promote structural measures for crisis management to minimize damage when flooding occurs, in addition to structural measures for outflow prevention



 Structural Measures for Outflow Prevention

Levees will be improved beginning with high-priority sections to prevent overflow and seepage.
The MLIT will continue to work on structural measures for outflow prevention to enhance safety against seepage and erosion and to increase discharge capacity.
For the length of 1,200 km of high-priority sections, the improvement measures are planned to be completed in about 5 years, by 2020.



Example 1
Piping / Slope Slip
-> Leakage Prevention
　　   including seepage
Length = approximately 360 km
  (seepage prevention on the levee)
Length = approximately 330 km
  (piping prevention)
- Risky sections of levee breach due to seepage etc.
- Potential sections of piping such as former riverbed
Example 2
Lack of Flow Capacity
-> Levee Improvement and
 Channel Excavation
Length = approximately 760 km

- Incomplete sections for target capacity due to such reasons as lower levee height (to be improved keeping up-and-downstream balance)

Example 3
Erosion / Scour
-> Erosion Control and
 Scour Prevention
Length = approximately 110 km
- Dangerous sections at risk of riverbank erosion and revetment failure


-> Prioritized sections: approximately 1,200 km
　


 Structural Measures for Crisis Management

The MLIT will promote reinforcements to prolong the time before a levee is breached, even when overflow occurs. 　　　　　　　　　
For the 1,800 km section at high where levee improvement cannot be conducted while keeping an up-and-downstream balance, the MLIT will promote reinforcements to prolong the time before a levee is breached. This will be completed in about 5 years, by 2020.




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