Monitoring and surveillance of embankment dams - Geotechnical Engineering of Dams - page 839

Guide for “in service” embankment dam monitoring frequencies 1 (Adapted from ANCOLD, 2003).

Table 20.11.

Consequences of failure category

Monitoring Very low Low Significant High Extreme

Monthly 5 Daily to twice weekly (TC) 2 Daily to tri weekly (TR) 2 Daily (TR) 2

Rainfall Monthly

Monthly 5 Twice weekly to weekly (TC) 2 Daily to tri weekly (TR) 2 Daily (TR) 2

Storage level Monthly

Monthly 5 Twice weekly to weekly (TC) 2 Daily to tri weekly (TR) 2 Daily (TR) 2

Seepage Monthly

Chemical analysis and pH of seepage Consider Yearly Yearly

Pore pressure 3

Consider 3-monthly Monthly to 3-monthly Monthly

Surface movement, control 4

Consider Consider 5-yearly to10-yearly 5-yearly

Surface movement, normal Consider 2-yearly Yearly

Internal displacement 2-yearly Yearly

Seismological 3

Consider (TC) Consider (TR)

Notes:
1 These frequencies may need to be varied according to the conditions at, and the type and size of dam, and applies to instrumentation already installed at the
dam.
2 The frequencies quoted assume manual reading of the instrumentation. Where automated readings are available more frequent reading would be appropriate.
(TR - telemetry recommended; TC - telemetry to be considered).
3 The frequency of reading and location of the pore pressure instruments and seismic instruments need to be at the discretion of the dams engineer.
4 A control survey uses monuments that are remote from the dam site to check the location of the survey monuments at the dam site.
5 The frequencies listed for very low consequence of failure category dams are suggestions, the dam owner should determine appropriate monitoring.
6 Applicable for concrete dams and construction on potentially soluble materials or where there is concern about seepage in the dam or its foundations.

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