Guidance for the preparation, approval, and archiving of aquifer-test results


In Reply Refer To:                          June 2, 1994
Mail Stop 411



OFFICE OF GROUND WATER TECHNICAL MEMORANDUM 94.02


Subject:  Guidance for the preparation, approval, and archiving
          of aquifer-test results

Analyses of aquifer tests to define the hydraulic characteris-
tics of a specific aquifer or aquifer system are an integral
part of our interpretive ground-water investigations.  The
results of these analyses are critical components of flow-system
or solute-transport analyses and important to conclusions
published in U.S. Geological Survey (USGS) reports.  Conse-
quently, reported aquifer characteristics such as hydraulic
conductivity, transmissivity, storativity and other hydraulic
characteristics derived from aquifer-test analyses must be
clearly documented and technically defensible.  The purpose of
this memorandum is to describe guidelines and procedures
necessary to obtain approval for the results of aquifer tests
analyzed by employees of the Water Resources Division (WRD) and
to provide guidelines for archival of the test results.


BACKGROUND

According to WRD Publications Guide (Article 11.01.2) "....calcu-
lated hydraulic characteristics such as transmissivity, hydrau-
lic conductivity, and storage coefficient, are interpretive and
must be approved by the Director, unless cited from a Director-
approved report."  In a memorandum dated March 11, 1992, the
Assistant Chief Hydrologist, Scientific Information Management,
delegated authority to approve aquifer-test results to the
Regional Hydrologists.  Approval is required for all calcula-
tions of aquifer-hydraulic characteristics to be released to the
general public, to cooperators, or published in or otherwise
used to support the results of investigations reported in
USGS-approved reports.

Estimates of aquifer-hydraulic characteristics commonly are
obtained from "textbook" or published values for various
lithologies.  These are not considered calculations of aquifer
characteristics and do not require approval under the terms of
this memorandum.  In addition, estimates of transmissivity
determined on the basis of specific-capacity measurements do not
require approval.


DOCUMENTATION, APPROVAL, AND ARCHIVAL OF AQUIFER-TEST RESULTS

While the USGS encourages the publication of aquifer-test
results, it is not feasible to publish the data and graphical results
for every test conducted.  In all cases, either as part
of a formal report or as a separate packet, aquifer-test results
should be submitted to the Regional Ground-Water Specialist for
review and subsequent approval by the Regional Hydrologist.  The
Regional Ground-Water Specialist reviews the report manuscript
or aquifer-test packet to assess (1) that the report or packet
contains the necessary data and related information to properly
analyze the subject test(s), and (2) that the analyses and
results are technically defensible.

Elements that typically should be submitted for review are
listed below.  These elements assume an aquifer test comprising
a pumping well and one or more observation wells and should be
modified as appropriate for other types of tests such as a
single-well slug test. The eight elements are as follows.



1.  A brief description of the test (this can be neatly
    hand written) which includes the purpose, date, test
    procedures, and methods of analysis of the results.
    Any unique or unusual features or problems related to
    the test or to the collection and analysis of test
    data should be described.  A brief description of the
    assumptions used in analyzing the test results also
    should be included, as needed to clarify the test.

2.  A sketch of the test site showing the distances from
    the pumped well to all observation wells and the
    location of any boundaries, streams, springs, ditches,
    pumping or flowing wells, or other features that
    possibly could influence test results.  Where the test
    includes multiple wells, the sketch of the test site
    should be drawn to scale.

3.  Description of test and observation well construction,
    including screened and open interval(s), casing and
    screen diameters, and location of filter pack and
    grouted intervals.

4.  A description of the site hydrogeologic characteris-
    tics, including sections that show the major water-
    bearing and confining zones or units.  The intervals
    of the pumping and observation wells that are screened
    or open should be depicted on the logs or sections.

5.  Time-discharge records of the pumped well (all
    measurements, not just average discharge).

6.  Water-level records and hydrographs showing pre-test
    trends and water levels during the pumping and
    recovery phases.

7.  Description of methods and computations showing
    adjustments to drawdown for pre-test trends,
    adjustments of recovery for projected drawdown, or
    adjustments to account for extraneous effects not
    related to pumping or recovery, such as barometric and
    tidal effects or other interferences.

8.  All plots of observed or adjusted drawdown or recovery
    data used to determine hydraulic characteristics,
    showing match points, when used, and computations.

It is recognized that in some cases it is not possible to
provide a complete description of these eight elements.
Investigators are encouraged to discuss their plans with the
Regional Ground-Water Specialist to determine the requirements
for a particular test packet or report before they forward it
for review and approval.

A transmittal memorandum, indicating that the test results have
been reviewed by the District or Area ground-water specialist or
his or her designee, should be included with the test packet or
report.  This review should include at least some checking of
the field data and a verification that the test results are
appropriate, given the site hydrogeology, well construction, and
test conditions and that the test results have been reviewed
independently before being submitted for regional review and
approval.

Following approval by the Regional Hydrologist, the packet or
report will be returned to the originating District or Office
where the hydraulic characteristics and related site and well
data should be entered into the Ground-Water Site Inventory
System or National Water Information System (NWIS) and the
packet and associated information appropriately archived in a
District "aquifer-test file."  These archived aquifer-test files
should include the draft-report routing sheet or packet-review
transmittal memorandum.  Districts also are encouraged to
archive test analyses and results completed prior to this
memorandum.  The aquifer-test files will be reviewed as a
routine part of District ground-water discipline reviews.

If computer software is used in the aquifer-test analysis,
the policy outlined in Office of Ground Water Technical
Memorandum 91.04, dated August 14, 1991, must be followed.  This
policy requires that the theoretical basis of the software be
documented and that it be demonstrated that a test-data set can
be correctly analyzed using the software.  Submittal of a
computer-software analysis does not eliminate the need for the
information described in item element 8, above.

This memorandum discusses information needs in the context of
single- or multiple-well aquifer tests. Aquifer characteristics
also may be calculated by other methods, such as, determination
of aquifer diffusivity from attenuation of a tidal pulse or
flood wave through an aquifer, or using hydrograph-recession
characteristics.  The same review procedures should be followed
for these types of analyses, and information in the report
manuscript or packet must be adequate to enable reviewers to
visualize the physical system, evaluate all data, verify all
calculations, and assess that the methods and results are
defensible.

                                   Sincerely,




                                   /s/ William M. Alley
                                   Chief, Office of
                                   Ground Water

Attachment

Distribution:  A, B, S, FO, PO