Research Trends and Results
Upgrading Maintenance Technology to Support Dam’s Long LifeSAKURAI, Toshiyuki Senior Researcher; OKOSHI Moriyuki , Researcher; SASAKI Takashi(D.Eng.), Head
Large-scale Hydraulic Structure Division, River Department
Keywords: support dam’s long life, maintenance, comprehensive dam inspection, database
1. Introduction
Dams have the functions of flood control, waterutilization, etc. and constitute important social capital.
Many dams have been constructed to date in Japan. The
MLIT controls about 120 dams at present, and started
managing about 10% of them more than 50 years ago andabout 50% more than 30 years ago. For the dams under
the control of the MLIT, a "Comprehensive Dam
Inspection Guidelines" 1) was established in 2013 in orderto promote more effective and efficient maintenance on along-term perspective. Based on this procedure, each dam
is subject to comprehensive inspection at an interval of
about 30 years and the support plan for dam’s long life
are being formulated.
Given the situation, it is desirable to upgrade
maintenance technology in order to maintain the safety
and functions of dams for a long time.
2. Efforts to upgrade dam maintenancetechnology
In order to maintain the required functions of dams
under the direct control of the MLIT, daily inspections
have been conducted by dam administrators and periodic
surveillance have been conducted by professionals inprinciple every 3 years, in accordance with the inspection
and maintenance requirements provided for in operating
rules, etc. of each dam. Based on the results of these
inspections, dams have been maintained in place withrepairs as required. Information concerning maintenanceincluding inspection, measurement, and repair histories
has been accumulated by each dam administrator in theform of paper data or electronic information.
In order to upgrade dam maintenance technology, it isnecessary to detect the age-related deterioration
characteristics of dam structures and establish soundness
evaluation methods. In order to study these issues, it isnecessary to organize the accumulated management dataon each dam into a database of unified format that would
facilitate comparisons of the electronic data. Moreover,sharing the integrated database among dam
administrators will enable the examination of facility
repair and replacement from a broad perspective withreference to cases of other dams. (See figure.)
Therefore, the Large-scale Hydraulic Structure
Division is working to create a dam maintenancedatabase. Data on each dam will be registered in thisdatabase. We have built a prototype system in whichcollected dam data owned by MLIT have been registered.
Registration items are as follows.

Registration data: (i) Basic information (specifications
and basic drawing of the dam), (ii) Observation data
(history of earthquakes, floods, etc.), (iii) Inspection data
(daily inspections, extraordinary inspections, variousmeasurement values, etc.), (iv) Surveillance results, (v)Repair / Replacement information, (vi) Maintenanceplans.
Dam manager

Registration

Utilization

Utilization

DamMaintenanceDatabase

Head Office of MLIT

Utilization

Regional Development Bureau

OtherDB
Conduct inspections, etc. and create data

OtherDB

Example of utilization: Reference to repairs inother dams

Collaboration withother database

Figure: Image of Dam Maintenance Database
Utilization
3. Future schedule
We will take the opinions of dam administrators about
the database, and plan to improve the convenience of thedatabase system. Furthermore, through comparative
studies and trend analyses using various management
data that we have registered in the database, we willcontinue to clarify the age-related deterioration
characteristics and examine soundness evaluation
methods for dam structures.
[Reference]
1) River Environment Division, Water and Disaster
Management Bureau, MLIT: "Comprehensive Dam
Inspection Guidelines / Commentary", October 2013