19 10 /:17 c..1 071794 {lLENIDl!NG DEPARTMENT OF NATIONAL RESOURCES NATIONAL DEVELOPMENT BUREAU OF MINERAL RESOURCES, GEOLOGY . AND · GEOPHYSICS BMR Record 1980/29 . GROUNDWATER SUPPLY FOR NATIONAL FITNESS CAMP AT BLOCK 10, PADDYS RIVER DISTRICT, by P.D. Hohnen The informati'on contained in this report has been obtained by the Department of National Resources a .. oart of the policy of the Austr alian Government to assist in the exploration and development of ' al resources . It may not be published in any form or used in a company prospectus or statement ut the permission in writing of the Director •. Bureau of Mineral Resources. Geology and Geophysics. Record 1980/29 c.3
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BUREAU OF MINERAL RESOURCES, GEOLOGY .AND· · Bore PR2 Bore PR3 Bore PR4 Bore PRS AQUIFER TESTS ANALYSIS OF AQUIFER TESTS GROUNDWATER. CHEMIS TRY CONCLUSIONS AND RECOMMENDATIONS
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DEPARTMENT OF NATIONAL RESOURCES NATIONAL DEVELOPMENT
BUREAU OF MINERAL RESOURCES, GEOLOGY .AND · GEOPHYSICS
BMR
Record 1980/29 .
GROUNDWATER SUPPLY FOR NATIONAL FITNESS CAMP
AT BLOCK 10, PADDYS RIVER DISTRICT, ~CT.
by
P.D. Hohnen
The informati'on contained in this report has been obtained by the Department of National Resources a .. oart of the policy of the Australian Government to assist in the exploration and development of
'al resources . It may not be published in any form or used in a company prospectus or statement ut the permission in writing of the Director • . Bureau of Mineral Resources. Geology and Geophysics.
Record 1980/29
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Record 1980/29
GROUNDWATER SUPPLY FOR NATIONAL FITNESS CAMP
AT BLOCK 10, PADDYS RIVER DISTRICT, ACT.
by
P.D. Hohnen
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CONTENTS
ABSTRACT
INTRODUCTION
BORE SITING
CONSTRUCTION OF BORES
Bore PR1
Bore PR2
Bore PR3
Bore PR4
Bore PRS
AQUIFER TESTS
ANALYSIS OF AQUIFER TESTS
GROUNDWATER. CHEMIS TRY
CONCLUSIONS AND RECOMMENDATIONS
REFERENCES
TABLES
1. Logs of water bores
2. Hydraulic parameters of fractured-rock aquifers
FIGURES
1. Location of National Fitness Camp in Paddys River
District (I55/A16/2290).
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Location of water bores at National Fitness Camp
(ISS/ A16/229l).
'Slug' test on bore No. PR1 (I55/A16/2292).
32-hour drawdown test on pumping bore No. PR4
(I55/A16/2293).
Page
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3
3
-4
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5. Residual drawdown test on bore No. PR4 (I55/A16/2294).
time Since purnpli'y started -=- time Since p("/n7j//~ sro;:ped (t.~2) ,c16U~£" 8
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3.
AgUIFER TESTS
While bore PR5 was being drilled, bore PR4 was pumped for 3 48 hours at 13.6 m /h. Drawdown and recovery of PR4 were monitored and
the aquifer constants (see Table 2) were calculated.
After drilling bore PRS, it was pumped for 48 hours at 4.5 m3/h,
and drawdown was monitored in the pumped bore and in PR4 50 m to the south.
Residual drawdown was monitored in PRS on cessation of pumping: the bore
recovered fully in 7 hours.
ANALYSIS OF AQUIFER TESTS
Plots of drawdown and residual drawdown for the pumped bores
are shown in Figures 4 to 10. Two of these plots (Figs 6 & 8) approximate
s·traight lines. The steeper slopes are attributed to casing-storage '
effects and are disregarded in the analyses. The flatter slopes were used
to determine transmissivity by the non-steady-state equation:
T=~ 4'11'liS
where Q=pumping rate (m3/day); and liS = drawdown/
log cycle.
The six aquifer tests done on interconnected fractured-rock
aquifers intersected by bores PR4 and PRS indicated transmissivities ranging 2 from 7 to 32 m /day, and the mean value is 2 16 m /day. Two values of storage
coefficient were calculated 8.4 x 10-4 and 0.5 x 10-4 • , these values confirm
earlier findings that the aquifers are confined.
The plot of drawdown recorded in pumping bore PR4 against log
time, shows a point of inflection about six hours after the start of pumping
(Fig. 4). This may indicate that about six hours after pumping started, the
cone of depression had spread to intersect an aquifer of much higher
transmissivity. producing a recharging effect on the drawdown curve (Fig. 4).
There is no clear evidence of recharge on the drawdown plot of pumping bore
PRS (Fig. 6). Here, the point of inflection occurred about 18 minutes after
the start of pumping, and appears to be the time at which casing storage
has ceased to affect the slope of the drawdown curve. The change of slope
of the drawdown curve could also be attributed to intersection of a ~echarge
4.
boundary close to PRS but distal to PR4 - i.e., just to the north of PRS.
This interpretation is supported by the fact that pumping from PR4 at
13.6 m3/h for 48 hours caused no measurable drawdown in PRS, whereas when
bore PRS was pumped at only 3.6 m3/h, a drawdown of one metre was effected
in PR4. Because a recharge boundary was suspected to have been intersected
by the pumping test on PR4, the aquifer test was analysed by Stallman's
method (Hazel, 1973; Fig. 9). This interpretation shows that a recharge
boundary was intersected at a distance of 50 m from the observation well,
distal to the pumped well. The mechanism used to explain this occurrence
is shown schematically in Fig. 10. Image well theory is used to simulate
the effects of the recharging source, which may be a fault just to the north
of bore PRS (Fig. 2).
GROUNDWATER CHEMISTRY
A full chemical analysis has been made of a sample of water
pumped from bore PRI in 1975. The water is essentially a carbonate water