PUBLICATIONS--Open file report, "Definitions of Selected Ground-Water Terms," by S. W. Lohman and others.

                          GEOLOGICAL SURVEY
                      WATER RESOURCES DIVISION
                       WASHINGTON, D.C. 20242

                                              September 16, 1970
                                                       4300 5016


To:       Regional Hydrologists and District Chiefs, WRD

Through:  Assistant Chief, Research and Technical Coordination

From:     Chief, Ground Water Branch, WRD
          Washington, D.C.

Subject:  PUBLICATIONS--Open file report, "Definitions of Selected
                        Ground-Water Terms," by S. W. Lohman and

The subject report, the product of an ad hoc committee proposed in
1965 by J. T. Callahan, then Associate Chief of the Ground Water
Branch, and activated in 1966 under the chairmanship of A. N.
Piper, has been approved for publication as a Water-Supply Paper
and is now being processed.  It was approved also for release to
the open file, and copies are now available for use within the
Division.  A standard distribution is being made.

In addition, it is the intention that each ground-water
specialist, plus each other person responsible for working with
reports relating mainly to ground water, have a desk copy of the
open-file report pending publication as a Water-Supply Paper.
These additional copies will be furnished upon request to S. W.
Lohman, WRD, Denver, Colorado, who succeeded A. N. Piper as
chairman of the committee and was responsible for final
coordination, assembly, and reproduction of the report.  Please
let Mr. Lohman know how many additional copies you require.
Requests should not include a cushion for future needs, for
cooperators, or for the general public.  Such special needs should
be justified in writing to the Chief, Ground Water Branch.

The definitions are standard and are to be used in manuscripts
prepared from now on; manuscripts already completed need not be
changed unless it is convenient to do so.  In accordance with the
statement on page 3 of the report, an author may express a
preference for and use a different definition once the standard
definition has been made clear, so that the reader will be in no
doubt as to what the standard usage is.

Use of consistent units (for example, all measurements of length
in the same units, all measurements of time in the same units) is
preferred and is to be adopted as rapidly as possible.  It is
recognized, however, that for an indefinite period it will be
necessary to use inconsistent units (such as gallons per day per
square foot) in reports prepared for particular audiences.  In
such manuscripts both consistent and inconsistent units should be
given for the reader's information and to aid in the eventual
transition to near-exclusive use of consistent units, along the
same lines as using English measurements and giving their metric
equivalents in parenthesis.

The definitions were prepared and meticulously reviewed by members
of the committee who include some of the leading ground-water
authorities, and it is believed that they will not be found to
include any significant errors.  Should anyone spot a point he
considers questionable, he is asked to communicate with this
office in order that it can be checked out.

                                   (s) C. L. McGuinness