The following monitoring and reporting requirements are
applicable to all instrumented dams under normal, long term operating
conditions, unless otherwise approved by the State Engineer. Under unusual
conditions, the State Engineer may require additional criteria. Instrumentation
requirements for new dams should be outlined in the Initial Filling Plan as per
R655-12-3A. The type of
instrumentation required is presented in
R655-11-10.
1. Seepage in the vicinity of any dam shall
be monitored, typically including lateral extent, turbidity and flow rate.
Collection in a properly designed drainage system as outlined in
R655-11-6E may be
required.
2. All piezometers and
drains shall be monitored at least monthly when the reservoir exceeds 50% of
the hydraulic height. Where reservoir elevations vary substantially over an
irrigation season, readings shall be obtained on a weekly basis when the
reservoir exceeds 90% of the hydraulic height. Readings can return to a monthly
frequency four weeks after the reservoir level peaks, provided measurements are
stable and within anticipated ranges. In all cases, instrumentation should be
monitored at the beginning of the reservoir filling season, at the peak
reservoir elevation, and at the maximum reservoir drawdown.
3. The elevation of the reservoir shall be
recorded at the time of all readings as described in 2. above.
4. All dam instrumentation (including
piezometers, drains, reservoir gage, survey monuments, and any other dam
instrumentation) shall be monitored immediately following an earthquake where
ground motions are felt in the area or the owner is informed of seismic
activity in the vicinity. Results of the inspection and instrumentation
readings should be immediately sent to the State Engineer.
5. Copies of all instrumentation monitoring
data should be forwarded to the State Engineer, on a monthly basis, following
collection of the data. It is the responsibility of those obtaining the data to
know if readings are within normal historical and/or design operating
parameters. Emergency conditions should be assumed if readings exceed normal
historical and/or design operating parameters and immediate notification of the
State Engineer is required.
6. All
instrumentation shall be documented by plotting locations on a plan view of the
dam and by assigning a unique, identifiable name. A table for all instruments
which provides base line data shall also be prepared. Piezometer data should
include the name, location, monitoring location (e.g., zone 1, zone 2,
foundation), top elevation, total depth, and depth of porous interval. Drain
data should include the name, location, collection interval, and flow rate
monitoring methods. Survey monuments should include the name, location, and
vertical and horizontal coordinates. The reservoir storage gage should be
marked in at least one foot intervals and an elevation datum provided that is
consistent with all other dam instrumentation.
7. The data required for any other dam
instrumentation (inclinometers, temperature probes, chemical composition), will
depend on the type and purpose of the instrumentation.
