Your Dam Your Responsibility (PDF~1.2MB)

Appendix A
A
• probe – a ten-millimetre diameter by one metre long blunt end metal rod with right
angle ‘T’ handle at one end. The probe can provide information on conditions below
the surface such as depth and softness of a saturated area. Soft areas indicate poor
compaction or saturated material; and
• hammer – to test soundness of concrete structures.
(c) Observations to be Recorded
All measurements and descriptive details that are required to portray an accurate picture
of the dam’s current condition must be recorded. This information falls into three
categories:
• location – the location of any questionable area or condition must be accurately
described to allow it to be properly evaluated. The location along the length of the
dam should be noted, as well as the height above the toe or distance down from the
dam’s crest should also be measured and recorded. The same applies to conditions
associated with the outlet or spillway;
• extent of area – record the length, width and depth or height of any area where a
suspected problem is found.
• descriptive detail – a description of a condition or observation must be given which is
brief but yet containing all relevant details. Some factors to include are:
– quantity of seepage from point and area sources;
– colour or quantity of sediment in water;
– location, length, displacement, and depth of cracks;
– is area moist, wet or saturated?
– is protective cover adequate (topsoil/grass)?
– is surface drainage satisfactory?
– do batter slopes look too steep?
– are there bulges or depressions on the slopes?
– does deterioration appear to be rapid or slow? and
– have conditions changed? (note in what way etc).
Note: A sketch plan of the dam is a helpful aid to recording observations(see
Preliminaries). It should preferably be approximately to scale and the locations of all
observations should be indicated on it.
This is not a complete list but serves as an initial guide. If a condition has changed
since the last inspection, it must be noted; a photograph should also be taken and put
in the diary, noting the date and a description of the scene shown in the photograph.
Remember, a primary purpose of the inspection is to pick up changes which have
occurred since the previous inspection, and that if a situation looks as if it is worsening or
otherwise causes concern the owner should not hesitate to get professional help.
Table A1 is a typical form of checklist for noting defects and keeping long term records of
behaviour.
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