2016-03-01 Planning & Organisation Committee Agenda

Page 24 of 79

About this Report                                                                                  “/y

Introduction                                           e    A localised, perched water table may lead to
These notes have been provided to amplify DP's              an erroneous indication of the true water
report in regard to classification methods, field           table;
procedures and the comments section. Not all are       e    Water table levels will vary from time to time
necessarily relevant to all reports.                        with seasons or recent weather changes.
                                                            They may not be the same at the time of
DP's reports are based on information gained from           construction as are indicated in the report;
limited subsurface   excavations   and  sampling,           and
supplemented by knowledge of local geology and         e    The use of water or mud as a drilling fluid will
experience.    For this   reason,  they  must be            mask any groundwater inflow.    Water has to
regarded   as   interpretive rather  than  factual          be blown out of the hole and drilling mud must
documents, limited to some extent by the scope of           first be washed out of the hole if water
information on which they rely.                             measurements are to be made.
                                                        More reliable measurements can be made by
Copyright                                              installing standpipes which are read at intervals
This report is the property of Douglas Partners Pty    over several days, or perhaps weeks for low
Ltd. The report may only be used for the purpose       permeability soils.  Piezometers,    sealed in a
for which it was commissioned and in accordance        particular stratum,  may    be  advisable  in  low
with  the  Conditions   of  Engagement    for  the     permeability   soils or   where   there  may    be
commission supplied at the time of proposal.           interference from a perched water table.
Unauthorised   use  of this report in any form
whatsoever is prohibited.
                                                        Reports
                                                       The   report  has   been   prepared   by  qualified
Borehole and Test Pit Logs                             personnel, is based on the information obtained
The borehole and test pit logs presented in this       from field and laboratory testing,  and has been
report  are  an   engineering   and/or  geological     undertaken to current engineering standards of
interpretation of the subsurface conditions, and       interpretation and analysis. Where the report has
their reliability will depend to some extent on        been prepared for a specific design proposal, the
frequency of sampling and the method of drilling or    information and interpretation may not be relevant
excavation.     Ideally, continuous   undisturbed      if the design proposal is changed. If this happens,
sampling or core drilling will provide the most         DP will be pleased to review the report and the
reliable assessment,    but  this is  not  always      Sufficiency of the investigation work.
practicable or possible to justify on economic                     .         .                .
grounds.  In any case the boreholes and test pits      Every care is taken with the report as it relates to
represent only a very small sample of the total        interpretation of subsurface conditions, discussion
subsurface profile.                                    of geotechnical and environmental aspects, and
                                                       recommendations or suggestions for design and
Interpretation of the information and its application  construction.     However,   DP    cannot   always
to design and construction should therefore take       anticipate or assume responsibility for:
into account the spacing of boreholes or pits, the     *    Unexpected variations in ground conditions.
frequency of sampling, and the possibility of other         The potential for this will depend partly on
than ‘straight line’ variations between the test            borehole   or  pit  spacing   and   sampling
locations.                                                  frequency,
                                                       e    Changes in policy or interpretations of policy
                                                            by statutory authorities; or
Groundwater                                            e    The     ee    of contractors   responding to
a ap moyen              —_    are ‘bg           In     If thane cea BP will be pleased to assist with
samnety — CIS ATF OAR          IPERSRGAE BRCM,         investigations or advice to resolve the matter.
e    In low permeability soils groundwater may
    enter the hole very slowly or perhaps not at all
    during the time the hole is left open;

                                                                                                 July 2010

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