PROGRAMS AND PLANS--Frequency of Levels at Streamflow Gaging Stations.

In Response Reply To:
WGS-Mail Stop 415                          February 28, 1990


OFFICE OF SURFACE WATER TECHNICAL MEMORANDUM NO. 90.10

Subject:  PROGRAMS AND PLANS--Frequency of Levels at Streamflow
                              Gaging Stations.

The present recommendation for the frequency of levels at
streamflow gaging stations is that they be run at least every 3
years (Kennedy, 1988, p. 20).  There are many stations that are
located in stable areas for which levels could be run less
frequently.  This memorandum discusses guidelines for when less
frequent levels may be run.

The guidelines for levels frequency given by Kennedy (1988, p. 20)
are to be followed unless it can be shown that the station is
stable.  Stability involves the well and shelter, staff gages,
wire-weight gages, reference points, and reference marks.  If any
of these items is unstable, then Kennedy's recommendations are to
be followed.

If after at least 5 sets of levels over a period of at least 10
years, the gaging station is shown to be stable, a lesser
frequency of levels may be adopted.  Level summary sheets should
be prepared for all gages to provide for easy determination of
gage stability.  A recommended summary sheet format is shown in
Figure 18 of the report by Kennedy (1988) and a form for this
purpose that can be copied for District use is located on the last
page of Kennedy's report.

The OSW recommends that levels at regular gaging stations be run
at least every 5 years if stability is shown to exist.  It is also
recommended that levels at crest-stage gages be run at least every
3 years.  Additional levels may be needed if a major flood, or
other event, occurs that could disturb some part of the gaging
station.

As a matter of practice, it is also recommended that when levels
are run, the station description be reviewed and updated.  This is
not meant to preclude updates of the station description at other
times as needed.

If a variance in frequency from that proposed by Kennedy (1988) is
needed, a plan for frequency of levels is to be prepared by the
District and kept in the District files.  The District policy for
frequency of levels should be made a part of the District's
quality-assurance plan.

REFERENCE

Kennedy, Edward J., 1988, Levels at streamflow gaging stations:
    U.S. Geological Survey open-file report 88-710, 42 p.




                             Charles W. Boning, Chief
                             Office of Surface Water


WRD Distribution: A, B, S, FO, PO

This memorandum does not supersede any previous memorandum.