Monitoring and Maintenance of Stabilization Works
11.2 MONITORING
11.2.1 PURPOSES
An effective monitoring program accomplishes three things:
Detects the need for maintenance or repair in a timely fashion.
Provides a basis for designing repairs, if required.
Provides valuable insight into stream behavior and performance of
stabilization work, which can be applied to future projects.
11.2.2 CONCEPTS
Ideally, the critical elements of river characteristics and their impact on the design of
the protection work will have been considered and documented when the work was planned
and designed. The most vulnerable aspects of the work will also have been identified as part
of the planning and design process. Also, the as-built condition of the work will have been
documented as part of the construction operation. If some of this information is missing or
was never considered, monitoring activities will be compromised, but will still be worthwhile.
It is essential that monitoring detect any events or changes in stream characteristics
or the condition of the work that exceed design assumptions. Although the stream itself is
now the judge of whether the work is adequate, the fallacy in total reliance upon short-term
observations of the performance of the work is that, in the absence of a rare event, design
conditions will not be experienced until some future time. Therefore, all conclusions based
on monitoring should be tempered by consideration of the actual conditions that the
protection work has experienced.
Monitoring should include upstream and downstream conditions that may have future
impacts upon the project. Examples are:
Changes in upstream channel alignment may threaten bank stabilization works
downstream.
Channelization work may induce degradation upstream and may change
hydraulic and geomorphic conditions downstream.
Significant changes in operating procedures of reservoirs upstream of the
project site, or significant land use changes may change hydraulic and
geotechnical parameters at the site.
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