EP 1110-2-13
28 Jun 96
Chapter 4
embankment seepage, and foundation underseepage
and displacement of major elements of the structure.
Operation and Maintenance
Strong motion accelerometers are installed in
structures located in seismic regions. In the case of
older structures, which were designed using criteria
4-1. General
that have been revised due to changes in the state-of-
the-art, instrumentation provides most of the data
Problems may occur following many years of trouble-
necessary to evaluate the safety of the structure with
free operation of a dam. This is particularly so for flood
respect to current standards and criteria. After a
control dams which may not be tested by a significant
project has been operational for several years,
percentage of the maximum head for many years. Also,
scheduled maintenance, repair, and replacement of
any period of prolonged severe storming or severe opera-
instrumentation are included in the normal plan of
tion such as rapid drawdown warrants additional
operation (ER 1110-2-110). Detailed information on
attention during and immediately after the operation.
instrumentation for earth and rockfill dams is given in
This is particularly true for control structures such as
EM 1110-2-2300 and EM 1110-2-1908. Information
spillways, conduits, channels, and associated machinery.
on instrumentation for concrete dams is given in
Another category of higher risk involves those dams of
EM 1110-2-2200 and EM 1110-2-4300 (see also
advanced age which may be progressively deteriorating.
Lindsey et al. 1986, Keeter et al. 1986, Currier and
Rigorous and continuous vigilance, checking, and
Fenn 1986, and O'Neil 1989). Full reliance is not
inspection, for as long as the dam is operational, are
placed on instrumentation to forecast unsatisfactory
necessary for dam safety (James 1990, International
performance, since it is impractical to install enough
Commission on Large Dams 1987, Morrison-Knudsen
instrumentation to monitor every possible problem
Engineers 1986, Schurer 1988). Dam operations
area. An extremely important adjunct to an adequate
management policy is covered in ER 1130-2-419.
instrumentation program is visual observation to
determine evidence of distress (Duscha 1982). Project
personnel receive extensive training in basic
4-2. Operation and Maintenance Manual
engineering considerations pertaining to major
structures, with procedures for surveillance,
The O&M manual is prepared during the construction
monitoring, and reporting of potential problems, and
phase. The purpose of the O&M manual is to provide
with emergency operations (discussed in Chapter 7).
guidance and instructions to project personnel for proper
operation and maintenance of the facility. A general
outline for the O&M manual is given in Appendix I to
4-4. Initial Reservoir Filling
ER 1130-2-304. The O&M manual contains a narrative
summary of the critical features of the dam including
a. General. The "initial reservoir filling" is
design features with safety limits, the more probable
defined as a deliberate impoundment to meet project
failure modes that could lead to structure failure, and a
purposes and is a continuing process as successively
history of problems and how they could adversely affect
higher pools are attained for flood control projects.
the structure under stress (ER 1130-2-419).
The initial reservoir filling is the first test of the dam to
perform the function for which it was designed. In
order to monitor this performance, the rate of filling
4-3. Instrumentation and Monitoring
should be controlled to the extent feasible, to allow as
much time as needed for a predetermined surveillance
All Corps of Engineers dams are required to have an
program including the observation and analysis of
adequate level of instrumentation to enable the designers
instrumentation data (Duscha and Jansen 1988). A
to monitor and evaluate the safety of the structure during
DM on initial reservoir filling has been required for all
the construction period and under all operating
new Corps of Engineers reservoir projects since
conditions and furnish data on behavior for application
1979.
to future designs. Eachstructureisprovided with minimum
instrumentation to measure hydrostatic pressure,
4-1
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