Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 1 of 70.
POWER AND WATER AUTHORITY
NGUKURR WATER SUPPLY EVALUATION
REPORT 41/92
Andrew Moretti (Ted Warren & Assoc)
Peter Jolly
Patricia Tyson
A Baker
Water Resources Division
May 1992
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 2 of 70.
SYNOPSIS
LIST OF TABLES
LIST OF FIGURES
LIST OF ABBREVIATIONS
1. Introduction
2. Groundwater Source
2.1 Geology
2.1.1 Aquifer Occurrence
2.2 Aquifer Parameters
TABLE OF CONTENTS
2.3 Groundwater Movement and Recharge
2.4 Water Quality
3. Surface Water Source
3.1 Roper River Flow
3.1.1 Flow at GS 9030146 (Wilton River)
3.1.2 Flow at GS 9030102 (Hodgson River)
3.1.3 Flow at GS 9030250 (Roper River) 3.2 Water Quality
4. Comparison of Sources
5. Water Demand
5.1 Water Supply
6. Conclusion
7. Recommendations
8. References
APPENDICES
Appendix A
Appendix B
Appendix C
Ngukurr Groundwater Investigations
Bore Construction
Bore Completion Reports
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 3 of 70.
S"YNOPSIS
Various groundwater investigations have been undertaken at
Ngukurr (formerly Roper River Mission) in an attempt to locate
a suitable groundwater resource. These investigations resulted
in three production bores, RN 5955 and 6035 drilled in 1967, and
21481 drilled in 1982.
Water for the community's domestic needs is supplied from the
groundwater resource and from Roper River in a ratio of
approximately 85% to 15% respectively.
The production bores have been constructed in the Kookaburra
Creek Formation with the aquifer being at the basal contact of
the Yalwarra Volcanic Member and the underlying sediments. Bore
6035 is used in a standby capacity with bores 5955 and 21481
supplying 6.5 L/s and 7.3 L/s (respectively) when pumped in
conjunction. The groundwater is of marginal quality with high
hardness and NaCl levels. The water quality of the river water
is variable due to physical properties (turbidity and
bacteriological quality) and chemical properties (high salinities
at the end of some dry seasons) and will require treatment for
extended periods.
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 4 of 70.
2.1
2.4
3.1
3.2
3.3
3.4
3.5
3.6
3.7
5.1
5.2
5.3
Al
Bl
LIST OF TABLES
Ngukurr Groundwater Investigation - Slliumary of Results
Water Quality Data
Flow History for Wilton River
Flow History for Hodgson River
Flow ;.r· t •• l.S Ory for Roper River
Roper River Water Quality 1980
Roper River Water Quality 1986
Selected Water Quality Parameters
Ngukurr
Salinity at Various Tidal Conditions
Ngukurr Population Data
Current and Projected Water Demands
Pumping Rates and Pump Settings
Lithological Logs
Bore Construction Details
Roper River
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 5 of 70.
1 .
2.l(a)
2.l(b)
2.l(c)
3.1
3.2
3.3
3.4
A2 (a)
A2 (b)
A2(c)
Cl(a)
Cl(b)
C2(a)
C2(b)
C3 (a)
C3 (b)
Location Map
Bore Location Map
Geological Map
Local Geology and Bore Locations
LIST OF FIGURES
Stream Flow Recorder Stations Location Map
Three Year Moving Average Rainfall - Katherine 1873-
1984
Salinity and Tidal Variation 1964
Salinity and Tidal Variation 1966
Constant Discharge Test 21481
Constant Discharge Test 21481 OB 6035
Step Drawdown Test 21481
Composite Log of Bore 5955
Pumping Curve RN 5955
Composite Log of Bore 6035
Pumping Curve RN 6035
Composite Log of Bore 21481
Pumping Curve RN 21481
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 6 of 70.
kPa
L/s
km
m
rmn
ID
kL/d
TDS
R..11J
m2 /d
mg/L
mins
NaCl
co, kL
L
NB
u/m
m3 /s
kilopascal
litres per second
kilometre
metre
millimetre
Internal Diameter
kilolitre per day
Total Dissolved Solids
Registered Number
metres squared per day
milligrams per litre
minutes
Sodium chloride
Carbon dioxide
kilolitre
litre
Nominal Bore
microsiemens per metre
Cubic metres per second
ABBREVIATIONS
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 7 of 70.
1. INTRODUCTION
Ngukurr, formerly known as Roper River Mission, is located on the
northern bank of the Roper River, approximately 100 kms upstream
of the mouth and some 500 kms east south-east of Darwin (refer
Figure 1). The community is located on a prominent ridge within
the Roper River flood plain and is served by a sealed road from
the Stuart Highway at Mataranka to approximately 30km from Roper
Bar and then a formed gravel road. It is also served by a barge
landing on the Roper River and an airstrip. Ngukurr has a
population estimated at 800 persons, however, this figure varies
throughout the year due to population movements between
outstations and the community.
Domestic water for Ngukurr was originally obtained from the Roper
River. However, this was found to be unsuitable in the late dry
season, due to saline intrusion. Bores were drilled in
groundwater investigations in 1961, 1963, 1967, 1972, 1978 and
1982, in attempts to locate a suitable groundwater resource.
These investigations resulted in production bores 5955 and 6035,
drilled in 1967 and 21481, drilled in 1982. The three production
bores are located within 100m of each other about 3.5km north
northwest of Ngukurr. All other bores drilled around Ngukurr
have yielded little or no water, or brackish water.
Ngukurr currently has a combined surface water and groundwater
supply with the majority of domestic water being supplied from
the borefield in a ratio of approximately 85% groundwater to 15%
river water. The quality of the river water is acceptable for
a large part of each year, with salinity levels exceeding
acceptable li..rnits normally only towards the end of the dry
season. Turbidity also creates a significant problem and
treatment is sometimes needed for extended periods throughout
each year. In 1981 a slow sand filter was commissioned to
remove algae and suspended solids from river water. However,
difficulties were experienced due to the filter media clogging.
The plant has rarely been utilised.
This report was undertaken with the following objectives:
(1) Quantify current water usage and supply source capacity.
(2) Determine a management strategy for Ngukurr water supply
source.
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 8 of 70.
Adelaide River <I
i ~
Daly River Pine Creek
Oolloo
' KATHERINE
I;
Willeroo
./ JABIRU
NGUKURR
A THERINE
TENNANT CREEK
ALICE SPRINGS
Matarank
NHULUNBUY
Bulman
Roper Bar
~oes illW
Larrimah
rf:j ~ NGUKURR ~root• Eylandt
Numbulwar
Not To Scale
r-lathaA Rivero
LOCATION MAP
Fig. 1
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 9 of 70.
2. GROUNDWATER SOURCE
The following is an evaluation of the groundwater source based
on the inteLpretation of the results obtained from drilling, test
pumping and field observations conducted as part of the Ngukurr
Groundwater Investigations (1962, 63, 67, 72, 78, 82) Bores are
referred to by their registered numbers (RN) and the bore
locations are shown in Figure 2.l(a).
2.1 Geology
The physiography of the area surrounding Ngukurr consists mainly
of Proterozoic sediments that have been eroded to a mature
surface. Broad, flat-floored valleys have been formed on
incompetent shale, siltstone and carbonate sediments. Thin-
bedded fine-grained sandstone and greywacke form rounded, rubble
covered hills and the competent sandstone beds occur as long
escarpment-fOL;lled ridges.
Figures 2.l(b) and (c) present the geology of the area. The
producing bores around Ngukurr were drilled in the McArthur
Group. The base of the McArthur Group is formed by a
stromatolite-bearing dolomite at the bottom of the Vizard
Formation. The dolomite and siliceous sediments throughout the
rest of the formation contain some fine elastics and are
interbedded with sandstone beds. The overlying Mount Birch
Sandstone (subsequently renamed as the Smythe Sandstone Me..-nber
of the Balbarini Dolomite - refer reference 5) is feldspathic and
the upper white member is distinctive throughout the area. This
formation is the only dominantly sandstone unit in the Group, but
thin sandstone beds are present throughout the Kookaburra Creek
Formation (renamed as the Balbarini Dolomite) . The sediments in
the Kookaburra Creek Formation consist of silicified dolomites
in part oolitic with stromatolites, chert and ferruginous chert
breccia. The Yalwarra Volcanic Me..-nber (mainly basalt) represents
a period of vulcanism in the middle of the Kookaburra Creek
Formation. The presence of boulder conglomerate within this
member suggests that the volcanics also temporarily upset a
fairly stable period in the erosion of the nearest land mass.
The LLTflillen Sandstone forms the main hills to the north of
Ngukurr, while a superficial cover of sand, laterite and soil
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 10 of 70.
0 0
G
'
, /
,
)
\ )
(
'- - -, /
\ , -'. ,- -
\
\ .... ) ---
' '
I
\ -' !'-'-,
\ _ _: '
--r -- ,
- -
l
---~-
km 2 O
I
!
J
I '
I '
I
}
2
f
/ ,
\
PLAIN
11,,fQUNT ST GEORGE
~-'-:'P "' '-"'c. ' ' ~
w 4 km a
~~iiiiii"""~iiiii~~~~"!""~liiiiiiiiiiiiiiiiiiiiiiiiiiiiiil \ g "'1;,~303~0>.o><OmNimir-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~.:...:..::....~~~~~,~,~,,~0~0-0-m.JN~
(!]
• 2741 PRODUCTION BORE BORE WITH REGISTERED NUMBER MINOR ROAD OR TRACK CREEK
BORE LOCATION MAP Fig. 2.1(a}
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 11 of 70.
, __ ;
,
-J--F=/),'
'\ '
, , I
' I
( er1
' \_ ' \
'
,
'
/
\ , ' ,-, !'-"'-- __
/
' I ' I /I
/ / l
/ ,
/ J
r
)
' ' /''\.
, -' _,' .,_
--emu
mw
'
I I
, -
-~ I?mw
"=-?~-'a-"-_ ",~-........ ___,
.J---..-..--- .. - \ ,.. ----:::.'--- ,. - -'" ,,,.. I/' '\
Czs
- -- -
I
GEOLOGICAL
\ \
'
' ' ' 'l
l
er!
\
', Czs \
WALMUDGA PLAIN ------1 ------
\
emu
, f
MAP
---
\
r
\ \
--- ' ' ,_
(
\
Fig. 2.1(b)
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 12 of 70.
0
~{ < 0
~
"' c. 0
a: a:: w a. a. ::i
0 0 N c. 0 ::> a: 0 w ~
f- Cl 0 ~
a: ::> .c
"- -~ a: <
0 w :::;: 5: 0 --'
Mainoru Formation
Ummen Sandstone
Kookaburra Creek Formation
Yalwarra Volcanic Member
Mount Birch Sandstone
Vizard Formation
LEGEND
G Sand. lat.rue. soil. alluvlum. forruglnous gravel
,-edl ·· 1 Dolerite sills
~ G
fvficaceous 5jftstone, blocky chert, pink to cream silicified siltstone
!4assive and ffaggy sf/!cff;"ed quartz sandstone, micaceous quartz grey~vacke; basal quartz pebble congiomera te
Si/lcili~d dolomite in part oolitic, containing stromatofites. chert, ferruginous chert brtJccia, sandstone
Basalt, interbedd"d amygdafoida! b.asic and intermediate volcanics and feldspathfc sandstone: volcanic breccia and agg!omera te
White and brown feldspathic sandston~, calcareous near base
lnterbedded quartz s.andstone and siltstone, dolomitic in places; s/icified dolomite with stom:ato!ites. Chert ~1ith sponge spicJ,Jfes
GEOLOGICAL BOUNDARY FAULi STRJKi'O
-1' DJP <is·
- - - - - - - MINOR ROAD OR TRACK
- - - - - - - CREEK
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 13 of 70.
2mw
-- -- ---Czs
~</;: o~ ~
emh
MOUNT BIRCH
v
-
emh
I E'rl J
emu
' \
\
emw
,,.-~~~~~~~~~~\\ ...... ~,
' \ \
\
• 21507
emu
emh
\ 2738• \ I \
I I
~-L I ' ' I '
I \ \
\ \
\
I I I
I I I ,, I I
215cJ5- - - -< - - - - - -
Czs
I - -21506 I - - - - ~Z870
-
Czs
I I
\
2736 •
//•4098
~ • ~~-L:and/ng ..._ l gr.,und
- ....... \ , __
•2735
•2r39
1•4219 -<4099 \ \ 4100 \
\
\ - •2741 \ \
\
' ltff'EJ?, ---
'
km 2
\ \
(!]
•2741
\
.... -- -- - -,.,,,.,, - ..... Czs ....
' '
/
O 2 km
PRODUCTION BORE BORE WITH REGISTERED NUMBER MINOR ROAD OR TRACK GEOLOGICAL BOUNDARY FAULT STRIKE
emu
+ OlP<~S.,.
- - - - - - - MINOR ROAD OR TRACK
-- -
LOCAL GEOLOGY AND BORE LOCATIONS
;--
\ \
\
-
Fig. 2.1(c)
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 14 of 70.
masks the underlying Kookaburra Creek Formation on the Walmudga
Plain to the east.
The Showell Creek Fault runs north-south through the area. It
is a resultant right lateral fault with most of its activity
occurring after, and possibly during, the deposition of the
Kookaburra Creek Formation and Limmen Sandstone.
2.1.1 Aquifer Occurrence
Stratigraphically the formation of interest is the Kookaburra
Creek Formation. The Yalwarra Volcanic Member represents a
period of vulcanism in the middle of this formation and it is at
the contact between the volcanics and the underlying Kookaburra
Creek sediments where the current production bores struck water.
The formation dips at around 5° north.
Recharge to the aquifer is thought to occur through the weathered
dolomite of the Kookaburra Creek Formation. The Showell Creek
Fault and the fault immediately to the south of the production
bores could be possible sources of enhanced aquifer recharge.
Available data indicates the standing water level in the
borefield is close to the dry season water level in the Roper
River. Under the Walmudga Plain the dolomite is covered by only
a thin alluvial cover.
The Limmen Sandstone forms the main hills to the north of
Ngukurr. It has a very low permeability, therefore no
significant groundwater recharge of the weathered dolomite will
take place through the Limmen Sandstone.
A summary of the results of bore holes drilled in the Ngukurr
area can be seen in Table 2.1.
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 15 of 70.
TABLE 2 . 1 . NGUKURR GROUNDWATER INVESTIGATION - SUMMARY OF RESULTS.
BORE DATE DEPTH YIELD WATER QUALITY RN DRILLED DRILLED (L/s)
(m)
2735 23/09/61 17.4 nil 2736 25/09/61 3.8 nil 2737 28/09/61 31.7 seepage unpotable 2738 29/09/61 10.2 nil 2739 02/10/61 12.8 nil 2740 03/10/61 10.6 nil 2741 04/10/61 16.2 nil 2742 05/10/61 11.7 nil 2743 06/10/61 21.6 0 .25 unpotable
4219 27/09/63 43. 9 0.3 unpotable 4098 10/10/63 85.3 0.5 unpotable 4099 14/10/63 38.1 4.5 unpotable 4100 17/10/63 19.4 0.25 unpotable
5955 16/11/67 57.9 12.5 potable Pn::ducticn bore 6035 11/12/67 50.9 12.5 potable Pn::ducticn bore
7868 01/06/72 106.7 nil 7869 18/05/72 121. 9 nil 7870 05/06/72 48.8 2.5 unpotable
9323 25/09/78 15.0 nil 9324 05/10/78 35.0 nil 9325 11/10/78 31.5 0. 6 potable
21503 12/06/82 80.0 1.5 potable 21504 13/06/82 27.0 nil 21505 14/06/82 54.0 1.3 potable 21507 16/06/82 43.0 nil 21481 15/06/82 49.0 15 potable Pn::ducticn bore
2.2 Aauifer Parameters
The only bore drilled in the Ngukurr area that has been
comprehensively test pumped is 21481. A 24 hour constant
discharge test was carried out on 2 July 1982 at a rate of 33
L/s. At 1400 minutes the bore forked and maintained a constant
discharge of 30 L/s until the completion of the test. Figure
A2(a) shows drawdown against log time for this test. Analysis
of the results gives a value of 446m2 /day for transmissivity.
For the duration of the constant rate test bore 6035, which is
55m from 21481, was monitored. The plot of drawdown against log
time for this can be seen in Figure A2(b). The results of the
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 16 of 70.
test were analysed and a value of 324m'/day was calculated for
transmissivity.
On 5 July 1982, a series of step tests were carried out on bore
21481 at rates of 27 L/s, 30 L/s and 33 L/s. The results can be
seen in Figure A2(c)
2.3 Groundwater Movement and Recharge
Very limited data exists on the recharge mechanism for this
aquifer system. It is expected, however, that recharge will occur
through the weathered fractured basalts and dolomites that occur
in the broken and fractured zone of the east-west trending fault
irrcrnediately to the south of the production bore (refer Figure
2.l(b)). Water levels in the borefield are similar to water
levels in the Roper River during the dry season, indicating that
these two water bodies might be closely interconnected. Seasonal
groundwater water level variations have never been ascertained.
For the purpose of this work, a seasonal variation of 3m a year
has been assumed. Insufficient data exists to estimate the
sustainable yield
equivalent to a
sustainable.
of the borefield.
continuous yield
2.4 Water Quality
However, current extraction
of 11 L/s appears to be
Water quality data available for the bores drilled at Ngukurr is
summarised in Table 2.4.
Bores 4099, 4100 and 7870, are all located on the low-lying
Walmudga flood plain. Their waters are brackish and are unfit
for human consumption. The salinity of these bores is due to
recharge from the Roper River during periods of low flow v1hen it
is subject to saline tidal influences. This occurs at the end
of the dry season.
The water quality for production bores 5955, 6035 and 21481 is
within the drinking water guidelines adopted by the Nt Department
of health (Reference 7) with the exception of the sample taken
on 10 August 1982 from bore 5955, which indicated a total
hardness of 626 mg/L. This sample would have been affected by
drilling and workover activities that took place in the borefield
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 17 of 70.
in June and July 1982. However, the water from the borefield is
generally hard and many chemical parameters marginal. The
hardness of the water is due to the limestones/dolomites of the
Kookaburra Creek Formation. The water will be corrosive due to
the high C02 levels. This can be alleviated by degassing
techniques (once the water has been pumped to storage
facilities), but this may in turn lead to scaling problems.
Further study of these problems is required.
Diesel was spilled down production bore 6035 in 1982. Although
the bore was subsequently cleaned out, there is a possibility
that this was not 100% successful due to the properties of diesel
(ie it floats on water) This being the case, further work
should be undertaken to determine the extent of the
contamination.
Technical R
eport WR
D92041
View
ed at 15:07:57 on 29/07/2010P
age 18 of 70.
TABLE 2.4 WATER QUALITr DATA
QUALITY (mg/L)
BORE DATE pH SPEC TDS Na K Ca Mg TOTA!, TOTAL Fe Si02 Cl so, N03 HCO, F NaCl COND HARDNESS ALKAL
4098 10/10/63 7.3 360 312 2200 310 4950 4098 17/10/63 6.7 2500 330 6500 4099 10/10/63 7.3 1800 340 3000 4099 10/10/63 7.8 1650 260 3000 4099 17/10/63 7.5 1900 410 3000 4100 17/10/63 7.3 5100 350 1600 5955 20/11/67 7.7 1500 1027 95 10 90 82 565 338 1. 3 40 0 184 0 -5955 20/12/67 8.0 535 8 6 4 69 298 282 4 10 0.3 172 0.4 -5955 16/11/68 7.7 1500 840 103 7 66 78 560 332 0.2 300 19 <1 203 0.9 -5955 10/08/82 7.1 1610 920 88 9 106 88 626 340 1.4 24 320 35 1 115 0.3 530 5955 06/06/85 7.6 1330 710 66 5 94 74 538 367 0.1 29 220 22 1 448 0.3 370 6035 12/12/67 7.9 1159 707 82 14 13 101 455 338 0.1 55 0 1.5 206 0.2 -6035 12/12/67 7.7 1008 700 70 11 7 104 450 304 2.6 40 0 0.4 185 0.2 -6035 08/12/67 7.7 1153 705 70 10 12 116 515 352 0.6 55 <.1 <.1 215 0.2 -6035 lQ/08/82 7.0 1230 690 58 8 91 70 515 384 0.3 166 29 1 468 0.2 274 7870 26/05/72 7.5 26490 8000 88 1010 107 1664 7870 26/05/72 7.3 27000 8000 75 1036 92 1697 7870 26/05/72 7.2 26490 8000 85 1020 104 1681 7870 16/01/76 8.0 1200 435 294 189 359 311 7870 12/03/76 8.0 1220 495 361 181 440 298 9325 07/02/79 8.2 870 520 23 13 60 80 478 <.1 52 14 22 1 0.7 -
21503 12/06/82 7.7 1090 610 so 39 38 81 427 372 0.9 20 140 28 2 543 0.3 230 21503 12/06/82 7.5 1150 630 53 9 60 81 482 343 0.3 19 175 24 1 418 0.2 290 21505 14/06/82 7.4 760 430 25 10 59 44 328 290 27 70 14 4 354 0.3 112 21506 14/06/82 7.4 1330 790 78 10 86 79 539 352 4.0 24 224 42 2 429 2.0 368 21481 15/06/82 7.3 1200 670 75 12 81 56 433 281 24 200 34 9 343 0.6 330 21481 02/07/82 7.0 1360 720 70 8 96 74 543 370 1.3 25 230 24 <1 451 0.3 370
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 19 of 70.
3 • SURFACE WATER SOURCE
This section outlines the available surface water data for the
Roper River at Ngukurr. It analyses available data and makes a
preliminary evaluation of the river water source.
3.1 Roper River Flow
The catch.~ent area of the Roper River at Ngukurr is some 75000
km2 and its flow behaviour is influenced by three main streams,
all of which have a streamflow recorder situated on them. These
are the Roper River at Red Rock (GS 9030250), the Wilton River
at Qualari Waterhole (GS 9030146) and the Hodgson River at Wulli
Pulli (GS 9030102) (refer Figure 3.1) Available low flow data
for each station is shown in Tables 3.1, 3.2 and 3.3.
3.1.1 Flow at GS 9030146 (Wilton River)
This station is situated on the Wilton River some 20kiu from its
confluence with the Roper River. A sUiumary of available data at
this site is shown in Table 3.1. According to the flow record
at the gauge, the Wilton River at GS 9030146 ceases to flow
during most years and normally ceases to flow before the Roper
River at GS 9030250. The quality of water in the Wilton is
good and features low salinities and low hardness (refer Tables
3.4 and 3.5).
3.1.2 Flow at GS 9030102 (Hodason River)
This station is situated on a large pool approximately 20km from
the Hodgson River confluence with the Roper River.
available flow data at this site is shown in Table
A summary of
3. 2 .
As can be seen from the flow data, the Hodgson River ceases to
flow for an extended period during every dry season. Therefore
the Hodgson river has little or no bearing on the dry season base
flows in the Roper River.
3.1.3 Flow at GS 9030250 (Roner Riverl
This station is situated on the Roper River upstream of Roper Bar
and hence upstream of the confluences with both the Hodgson and
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 20 of 70.
Wilton Rivers. Wet season flows at this site reflect seasonal
rainfall patterns over a large catchrnent area. Dry season flows
are maintained by groundwater outflow from the Mataranka area in
most years.
The magnitude and length of dry season flows is controlled by the
availability of groundwater. The extent of base flow variability
can be represented by way of correlation to the moving three year
rainfall for the upper catchment as shown in Figure 3.2. As can
be seen from Figure 3. 2 and Table 3 . 3, the cease of flow in
1966/67, 70 and 71 can be related to the low moving average of
rainfall for the same period. The data tabulated in Table 3.3
indicates that no-flow periods of at least four months have
occurred previously.
A study of water quality above and below Roper Bar in 1980 and
1986 highlighted discontinuities in the salinity levels between
the sites (refer Tables 3.4 and 3.5). Decreases in salinity
levels downstream of Roper Bar to a site near Ngukurr suggest
that either a volu.me of low salinity water is being introduced
to the river systa~ in this area or the storage of low TDS flood
water held in pools in this section of the river is extremely
large compared to the base flows.
Whilst some flow may occur into the Roper River downstream of the
GS 9030250 recorder site after ceasing to flow at GS 9030250, it
is doubtful that this would be of sufficient volume to greatly
affect salinity levels in the Roper River.
Storage of low salinity flood waters (refer Table 3.6) in the
river within large pools between Roper Bar and Ngukurr represents
a possible explanation of the lower salinities in this section
of the river. However, further analysis of the flow mechanisms
in this section of the river is required before a complete
understanding of the salinity reduction between Roper Bar and
Ngukurr will be possible.
3.2 Water Quality
The chemical quality of river water adjacent to Ngukurr is
acceptable most years with salinity levels going above acceptable
limits normally only towards the end of some years where the
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 21 of 70.
I I l / Q0
I 1
--J~§§O_Q.QQ!!'lft _____ ~ ~~---- ____ ---- ____ -~--------,~.:...____ _ _ --~ ------ __ L _____ ~:2§9.P_Q.Q1!l!:JJ __
.ei ' ~ l ~ ~1
1§ oi 411Y~ 1 I + l ~ io o, .-: 1 I I ~ 10 g: j / '*-I IO
01 :& 1_,,/ ~~ :2 M: ~ ~ , ..... ~ ~ l ~.-_. I
; ~ /i ~1~~ :, : / : .... '\[~ I t I / I I
- -_ J_ - - - - --- - -- ---~~ - - - ----- - --- - ~ - -Butmet:a - - - - J_ ----- - - --------1---- ------ ------~ --- --------- - _j_ -i : ~"' i // j l l- ffl!o'S: : } : / : l i g¢.la_...," ', ',' ', I I t -......::, ~ -, , I ... , ' , "' , I I ~I I 9si, I
I 1 f ~I J : "$> : : ~ l ' Mountain : / : .s.e : : "i - ' l ' Valley sa .~ : I
' '6 I 'Ci ' • - 11'.1ainoru 1 • ~ 1 ........ 1 I \'!:. - I I 1 , . ..., ! ---:-- --- --- g-----~- --\.~'=G~o3Crf0a-- -------s1 -:- ------ ---------:-- ------- ----- ~ -~~;---- ------: ~--..J'..,.--/~ : : .. 11 l : I f l '-. 1t; I 1 I I -
GS9i030089 / l ", "" : 1 .Ji": : ,,.. ~umbu!wa I ..e.. I \ I <., L 'II I / I 1 / <"'0 _ , I 1 1 .~ ""'~ , .,,.. 1
: ,,. ..... ..,.. : ~~-f" : :"# j/ ~ ,,,. : 1 ,, / ~.,. : : ;.:... - ... ~ GS9030250 Bt;; ~' ' -<:: j 1
__ es~~~GSS~09Qj- ___ ------~·~~- ________ l __ ~_[_ __ti ____ -~ ________ ---- --~--: \_~ I .,. ' : .... ' S4 I GULF ' : ~ : .,.~~ -C'"~1tl' 13 12 _ 1q l ~ ~ ~ : 14 ,- 11 Pb.t::?T Of ~
<1" 1 -:.it-' Roper 1· RdPER : ~ ;01s ROPD 19~ot"· Bar A6pt. , 4 'i I
; i A3 ~1 \~ CARPE1'lTARIA~ ; A4 <J; }-. I
l ~ : A7 Ai5 I ' ~ :
--,;;(lt'ii~~ l GS90301Q2 ~ ' , ~-... :
1 _ • is9oi~;~;t---r~ -------------r-~~----------T~~~f--------~;------- ~~------·-- ------------T-
~ J!--. AS: :r ~Af-1 \ : : Hodgson Downs : ~O : \ 1
\ 1
1 1: : I ~ ., I I I ' I I ;;_, I , l I \, :
~. l - ~ '~ I I -~ I 'to\i ~ ; I\ I i m I i ---t -- -----------1 --- ------------p~ ---~%¢"- ---1------- ---------i--~ --------~ -~a~h;~ -RJ,;;r------~- -i "\. Larrlmati ;J ~ : 1111; \ : I N I I :. \.I I 1 Q)r 1 1 a:; 1: '
UJ4 I I ...... I~ lW
EJ : JI A { •,'oE 01 I l ~ ·~ I
g l : Nutwood Oowhs 1..": :g
--~:e2ooooom01 ~---i- ---------,,.::: / \ _____________ _.: ------- ~~~---f---------- ~ -__ ;\ ___ 825oooom~.Jl~ I ::C I / ! I \ I
j ~ ~ ,// ~ : : I ~ I § l \ : : "<---l- ~/ I \
Dal.} Waters / i '4 ~.a1Jhin1~ Oo\'lns
I I ·- - -..,\
km 50
&BS
~GS9030001
0
SAMPLE WATER
GAUGE
MINOR
50 100 km
POINT 1986 WATER QUALITY SURVEY
STATION
ROAD
STREAMFLOW RECORDER STATIONS LOCATION MAP
Fig. 3.1
Technical R
eport WR
D92041
View
ed at 15:07:57 on 29/07/2010P
age 22 of 70.
E E
_J
1800-
1600
1400
------RAINFALL KATHERINE ------LOWEST FLOW AT GS9030250
ROPER RIVER (m 3 /s)
;;! 1200
LL z <( a:
.,, -· cc . ('..) •
1000 MEDIAN
-1.5 800
1.0
600
0.5
400-l-----~---~---~---~---~---~---~---~---~-~L-'t---L--~---+-o
1870/71 80/81 90/91 1900/01 10/11 20/21 30/31 40/41 50/51 60/61 70/71 80/81 90/91
YEAR
THREE YEAR MOVING AVERAGE RAINFALL KATHERINE 1873 - 1984
Technical R
eport WR
D92041
View
ed at 15:07:57 on 29/07/2010P
age 23 of 70.
-E n n
0 ., z
,, -· (Q • (,) .
------SALINITY LEVELS AT NGUKURR
------TIDAL VARIATION
800
600-
400-
200-
HIGH TIDE
LOW TIDE o+-L---"----'---'L-.--'---"-----'---"o--'---''----'---'--.------'---+----'---'----'----."---'---'-----'-----,--'-----"-'--'---~-..i
9/11/64 11/11/64 13/11/64 15/11/64 17 /11/64 19/11/64
SALINITY AND TIDAL VARIATION 1964
21/11/64 23/11/64
Technical R
eport WR
D92041
View
ed at 15:07:57 on 29/07/2010P
age 24 of 70.
E u u
0 "' z
-· (Q • (.)
.i:a.
------SALINITY LEVELS AT NGUKURR ~----TIDAL VARIATION
- - - - - - - - - SALINITY LEVELS AT WILTON RIVER
800 8
600 6
400 4
,_ Q) Q) -,_ .c: Ol Q) .c:
z 0 f-<(
er: <(
> w 0 f-
o+--------.-------~-------~------~-------.--------t-0"---------J~ 11/11/66 13/11/66 15/11/66 17 /11/66 19/11/66 21/11/66
SALINITY AND TIDAL VARIATION 1966
23/11/66
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 25 of 70.
TABLE 3.1
1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986
FLOW HISTORY FOR WILTON RIVER
SUMMARY OF LOW FLOWS AT GS 9030146
MINIMUM FLOW (m3 /s}
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.13 0.10 0.24 0 .21 0.0 0.0 0.0 0.0 0.0 0.0
PERIOD OF NO FLOW
19/06/64 - 25/11/64 13/10/65 - 14/12/65 16/07/66 - 27/01/67 17/08/67 - 18/01/68 12/09/68 - 21/12/68 20/09/69 - 20/12/69 07/06/70 - 06/12/70 05/08/71 - 07/11/71 28/07/72 - 09/12/72 16/09/73 - 19/11/73 18/11/74 - 13/12/74
11/10/79 - 03/01/80 16/10/80 - 08/12/80 10/11/81 - 21/11/80 22/09/82 - 11/12/82 13/08/83 - 01/12/83 09/10/84 - 26/12/84
approx approx approx approx approx approx approx approx approx approx approx
approx approx approx approx approx approx
5 months 2 months 6 months 5 months 3 months 3 months 6 months 3 months 4.5 months 2 months 1 month
3 months 2 months 11 days 2.5 months 3.5 months 2.5 months
0.0 27/09/85 - 05/11/85 approx 1.5 months 0.0 03/07/86 - Station closed 30/10/86
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 26 of 70.
TABLE 3 .2.
1965 1966 1967 1968 1969 1970 1971 1972 1973
1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986
FLOW HISTORY FOR HODGSON RIVER
SUMMARY OF LOW FLOWS AT GS 9030102
MINIMUM FLOW (m3 /s}
No record 0.0 0.0 0.0 0.0 0.0 No record 0.0 0.0
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
PERIOD OF NO FLOW
No record 27/03/66 - 05/12/66 25/05/67 - 30/12/67 05/07/68 - 26/12/68 09/05/69 - 19/12/69 02/05/70 - 13/11/70 No record 01/06/72 - 15/01/73 09/05/73 - 16/06/73 11/08/73 - 20/11/73 30/07/74 - 06/12/74 01/08/75 - 12/11/75 29/06/76 - 14/01/77 26/06/77 - 11/01/78 No record 01/06/79 - 04/01/80 24/05/80 - 21/11/80 01/06/81 - 20/11/81 14/06/82 - 14/12/82 06/06/83 - 22/11/83 06/06/84 - 16/11/84
approx approx approx approx approx
approx and approx approx approx approx approx
approx approx approx approx approx approx
8 months 7 months 5.5 months 7 months 6.5 months
7.5 months
4.5 months 4.5 months 3.5 months 6.5 months 6.5 months
7 months 6 months 5.5 months 6 months 5.5 months 5 months
0.0 08/07/85 - 04/11/85 approx 4 months 0.0 02/05/86 - Station closed 29/10/86
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 27 of 70.
TABLE 3.3
1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992
FLOW HISTORY FOR ROPER RIVER
SUMrA"..ARY OF LOW FLOW AT GS 9030250
MINIMlJM FLOW (m3 /s)
0.00 0.00 0.29 0.09 0.00 0.00 No record 0.00 0.09 0.70 1.30 1.00 1.00 0.50 0.66 0.79 0. 75 0.60 0.80 0.90 No record 0. 35 0 .25 0.30 0.08 0.40 0.40
PERIOD OF NO FLOW
08/09/66 - 13/01/67 127 days 14/09/67 - 01/12/67 79 days
25/09/70 - 25/11/70 62 days Missing record approx 60 days
Missing record approx 30 days Missing record
Missing record
Missing record
Missing record
Technical R
eport WR
D92041
View
ed at 15:07:57 on 29/07/2010P
age 28 of 70.
T AB L E 3.4
l\Ol'MR RIVER WATER QUALITY 1966 ALL VALUES EXCEPT PHOSPHA'l'E IN mg/L-1
SITE DISTANCE DATE TIME SAl<!P- SPEC pH 00 TURB Na K ca Mg HARD ALK Fe SiO~ Cl so, NO, PO, HCOJ F NaCl UPSTREAM LING COND ~ IN FROM bEPTH NTU MOUTH(km) ( rn)
Ngukurr 106.0 OB/10 1400 0.5 450 8.5 96 11 35 4 34 22 145 0.4 1 54 28 1 177 0.2 89 116. 0 09/10 1430 0.5 566 B.5 96 12 46 5 40 28 174 0.4 6 75 50 1 212 0.2 124 125. 0 08/10 1345 0.5 654 B.5 95 12 52 6 43 29 107 0.6 8 82 60 1 228 0.2 135
Mouth of 134. 0 Hodgeon 137. 0 08/10 1140 0.5 903 8.4 94 3.5 82 9 50 43 219 0.2 15 122 96 1 267 0.3 201 River
l'.iouth of 142. 0 08/10 1100 0.5 1090 8.4 97 0.5 101 11 52 48 230 -<0. 1 17 159 120 1 281 0.3 262 Wilton River
Roper 147.0 08/10 0955 0.5 1440 B.5 117 0.4 157 16 58 63 249 0.1 18 117 180 1 304 0.4 193 Bar
GS9030520 158.5 10/10 1130 0.5 1610 8.4 103 171 18 70 57 261 --:0.1 16 261 212 1 318 0.5 430 at Red Rock
Technical R
eport WR
D92041
View
ed at 15:07:57 on 29/07/2010P
age 29 of 70.
TA B L E 3.5
ROPER RIVER WATER QUALITY 1986 ALL VALUES EXCEPT PHOSPHATE IN mg/L-1
S!'l'E DIS'l'ANCE DATE TIME SAMP- SPEC pH 00 TURB Na K Ca Mg I!ARD ALK >'e SiO.a Cl so, NO, PO, HC03 F NaCl OPSTREAI>l LING COND % IN FROM DEPTH NTU MOUTH(km) (m)
Near 113.5 25/06 1345 0.5 280 8.5 96 54' 15 4 16 11 85 83 2 .2# 3 20 12 1 <5 101 0.1 33 Ngo.kurr 122.5 25/06 1310 0.5 270 8.3 95 41' 16 4 1B 12 94 90 1. 7tt 4 22 13 1 <5 110 0.1 36
133.0 13/06 1330 0.5 3;l0 8.4 120 35' 19 4 23 13 111 107 1.6# 6 25 16 1 <5 131 0.1 41
Mouth of 134. 0 Hodgson 138. 0 13/06 1710 0.5 390 0.4 94 25' 27 4 27 17 138 130 0.9 10 35 22 1 ,5 159 0.1 58 River
Motlth of 142.0 15/06 1545 0.5 520 8.3 16 40 5 32 21 166 157 0.9 13 55 32 1 <5 192 0.2 09 Wilton 145.0 26/06 1030 0.5 690 B.2 3 55 7 ·16 29 217 189 0.2 16 80 49 2 <5 231 0.2 133 River
GS9030520 153.5 20/06 0955 0.5 830 8.3 2.1 78 9 44 35 254 210 0.3 18 110 63 2 -<5 250 0.2 175 at Red Rock
* - DENOTES BXCBBSIVB TURBIDITY LEVELS
# DENOTES EXCESSIVE IRON LEV:BLS
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 30 of 70.
TABLE 3.6
SELECTED WATER QUALITY PARAMETERS - ROPER RIVER NGUK!JRR
D.l\.TE
12/11/74 14/11/74 19/11/74 21/11/74 25/11/74 05/12/74 09/02/75 04/03/75 13/03/75 26/03/75 24/04/75 08/05/75 22/05/75 19/06/75 03/07/75 24/07/75 14/08/75 09/10/75 09/10/75 20/10/75 06/11/75 21/11/75 05/12/75 20/01/76 13/02/76 27/02/76 23/04/76 06/05/76 20/05/76 03/06/76 01/07/76 24/07/76
CONDUCTIVITY us/m
210 290 380 430 450 510
am 570 pm 590
630 600 650 720 180 100
73 360 410 490 550 700 790
SUSPEl'JlJED SOLIDS mg/L
83 23
2 12 16
5 16 26 33 23
8 5 5
46 72 74 11
5 108
8 113
17
TURBIDITY NTU's
0.8 5.2 14 5.4 7.8 5.3 83 66 54 93 57 26 7.7 1.7 0.5 3 6.5 8 9.7 7 1.5 1.5 10 44 77 84 7.6
56 5
3.2 3.8
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 31 of 70.
Roper River ceases to flow relatively early in the dry season.
However, turbidity creates a problem and treatment is needed
sometimes for extended periods throughout each year. (Refer to
Table 3.6 for turbidity data for the period from November 1974
to July 1976). Limited data currently exists on the
bacteriological and liirL~ological quality of water in the Roper
River at Ngukurr.
River water adjacent to Ngukurr settlement has been sampled
continuously at various times, specifically to determine levels
of saline intrusion when river flows cease towards the end of the
dry season.
Salinity level variations with tidal levels are shown for periods
in the 1963 and 1966 (river ceased to flow in September) dry
seasons in Figures 3.3 and 3.4 respectively. As shown, there is
a direct correlation between the level of salinity in the river
water and the height of the tide in the river. Similar analysis
carried out between 30 July 1964 and 17 August 1964 at Ngukurr
displayed no correlation, with salinity levels being maintained
at 50 to 60 ppm irrespective of tidal variation (ie this being
earlier in the dry season when the river was still flowing) .
Laboratory analysis of various samples taken during December 1966
and January 1967 are shown below in Table 3.7.
TABLE 3.7 SALINITY AT VARIOUS TIDAL CONDITIONS
DATE TIME CHLORIDE(ppm) NaCl TIDAL CONDITION
21/12/66 1340 710 1172 High tide 28/12/66 0653 1125 1856 30 mins after high tide 02/01/67 0930 1380 2277 1 hr after record high
tide 03/01/67 1230 1270 2096 1 hr after high tide 24/01/67 0630 198 327 High tide outgoing 24/01/67 1530 328 541 Low tide 24/10/67 2210 298 492 After turn of small tide
* the samoles taken on 24/01/67 are affected by wet season flow beginning in the Roper river on 13 January with a flow of 121m3 /s occurring at GS 9030250 on 24 January. The reasonably high salinities still present may be due to the initial flushing of saline water at the start of the wet from upstream of Roper River.
From available flow data (Table 3.3) it can be seen that the
Roper River ceased to flow for 127 days from 8 September 1966 to
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 32 of 70.
13 January 1976. For the 1964 dry season, whilst there is no
recorded flow data, the three year moving average shown in Figure
3.2, together with gauge board readings at Roper Bar, indicate
a no-flow period of similar magnitude.
The data shown in Figures 3 .3 and 3 .4 indicate that salinity
levels in November 1964 reached a stage (NaCl greater than 400
ppm) where PU!uping of potable water would not have been possible
at even low tide. In the case of the 1966/67 dry season shown
in Figure 3.4, pumping of potable water would only have been
possible at low tides in November. This would be expected to
continue at least intermittently until the wet season flows
occurred in the middle of January. Correspondence from the
mission indicates a requirement to carry water from the Wilton
River for drinking water purposes during this period.
Correspondence also indicates that carrying of water from the
Wilton River was required during the 1962/63 dry season, although
there is no indication of how long a period it was needed.
A study of the data contained in Figure 3. 2 and Table 3. 3
indicates that for the 27 year period from 1966 to 1992, problems
with the che..-nical quality of the river water only occurred during
six of those years and then only for a period of two months per
year at the end of the dry season. This equates to less than 4%
of the 27 year period. It is possible that a detailed study of
the storage characteristics of
Ngukurr may provide a means
identifying the flow dynai-nics
the pools in the Roper River near
of alleviating this problem by
of the salt water and identifying
rock bars that may naturally (or with minor modifications) reduce
the effects of this late dry season intrusion of salt water on
high tides.
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 33 of 70.
4. COMPARISON OF SOURCES
From Sections 2 and 3 it is obvious that accurate analysis of the
two water sources at Ngukurr is difficult due to the lack of
suitable data.
The chemical quality of the groundwater source could best be
described as marginal with high hardness and NaCl levels. The
groundwater is corrosive unless facilities are provided to enable
degassing of the dissolved C02 • There is also a problem which
has resulted from the spilling of diesel down production bore
6035. Further work is required to determine the extent of
pollution and what clean-up work is required.
The physical properties of the groundwater are superior to those
of the river water and require no treatment.
Insufficient data exists to estimate the sustainable yield of the
groundwater resource. However, current extraction equivalent to
a continuous yield of 11 L/s appears to be sustainable.
Available data indicates that the chemical quality of the river
water source is superior to that of the groundwater source for
in excess of 95% of the period of record (1966-1992).
Insufficient data exists to adequately describe the physical
properties - turbidity, limnology and bacteriological quality -
of the river. It would be expected that more detailed studies
of these properties, in combination with the dynai-nics and storage
characteristics of the Roper River upstream and downstream of
Ngukurr, would minimise the problems being encountered with this
source.
The presence of lower salinity water in the Roper River below
Roper Bar suggests that either recharge of the river with low
salinity water may be occurring between Roper Bar and Ngukurr,
or the storage of low TDS flood waters held in pools in this
section of the river is extremely large compared to the input of
water from river base flows.
Section profiling and sampling of the river from Roper Bar to
Ngukurr in October would answer this question, as well as
identifying if more suitable sites exist for location of the pump
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 34 of 70.
intake for Ngukurr.
Quality and depth profiling at the present pump intake site would
provide information as to the possibility of varying pump intake
depth, with a view to avoiding pumping from the saline wedge when
it is present. The provision of a shut-off system for the river
Plli~ps dependent on salinity levels could also be incorporated.
Based on the chemical quality of the two sources, the water
supply should be sourced from the Roper River except for extended
periods of 'no flow' when the groundwater source would need to
be utilised in the latter months of the year.
Insufficient data exists to accurately describe the physical
properties of the river water source. However, problems with the
operation of the slow sand filter (and its low level of usage
since corrnnissioning) have been attributed to these properties.
Until further work has been undertaken to accurately describe the
properties (and hence recommended means of adequately treating
the water), it appears that usage of the groundwater source for
most of the year will be required.
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 35 of 70.
5. WATER DEMAND
Water demand is a function of population and per capita
consumption. The available population data for Ngukurr is listed
below in Table 5.1.
TABLE 5. l. NGUKURR POPUL.l'.TION D.Z\.TA
YEAR POPULATION SOURCE
1976 1981 1983 1985 1986 1991 2000
250 391 391 540 660 794 908
Australian Bureau of Statistics Australian Bureau of Statistics Dept of Community Development .1'.boriginal Development Commission Australian Bureau of Statistics Australian Bureau of Statistics Assumed population (for 1. 5% growth rate)
The present population of Ngukurr is approximately 800. However,
this figure varies due to the nomadic nature of some of the
population and the increasing decentralisation trends to
outstations. The population is likely to be highest during the
wet season when mobility decreases and supply to outstations
becomes more difficult. During this period there tends to be a
shift of population back to the main community at Ngukurr.
Water consu.~ption figures for the 161 day period from 29 August
1991 to 5 February 1992 indicated a total consumption of 179656
kL. This figure consisted of 152624 kL which was supplied from
the borefield and 27032 kL which was pumped from the Roper River.
The average consurr~tion for this period equates to 1390
L/person/day (assuming a population of 800) During this time
the peak 28 day consumption was 34160 kL or 1520 L/person/day.
The current
size. The
consumption at Ngukurr is high
recommended supply to cater
for a community if its
for col!lIIlunities with
populations over 200 (reference 6) is 800 L/person/day and 1200
L/person/day to cater for the peak demand.
From the above data, current and figure demands have been
calculated. This can be seen in Table 5.2.
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 36 of 70.
TABLE 5.2. CURRENT AND PROJECTED WATER DEMANDS
YE.AR
1992 2000
5.1
POPULATION
800 908
Water Supply
AVERAGE DEMAND (kL/d)
640 720
PE..l\.K DEV.LAND (kL/d)
960 1090
Water is supplied to Ngukurr from a borefield to the north
northwest of the corrrrnunity, as well as from the Roper River.
The borefield consists of bores 5955, 6035 and 21481, all located
within 100m of one another, approximately 3.5km north-northwest
of Ngukurr. Production bores 5955 and 21481 are serviced by
electrical reticulation, while 6035 is equipped with a 2 cylinder
diesel Lister motor and used as a standby bore.
Production bore 5955 is equipped with an electrified 720 Mono
pump and is currently supplying 6. 5 L/s (when pumping with
21481). This bore is cased with 140rrrrn NB steel casing and has
a recorrrrnended maximum continuous pumping rate of 12 L/s (pumping
alone). The bore is also fitted with a remote telemetry system.
Bore 21481 is equipped with an electrified submersible pump and
currently pumps at about 7 .3 L/s (together with 5955) with a
borehead pressure of approximately 400 kPa. However, it is
reported that when pumping alone, this pressure drops to
approximately 200 kPa, due to reduced friction losses and its
discharge rate increases to about 11 L/s.
Bore 6035 is equipped with a diesel driven borehole Plli~P unit
which has a rated supply capacity of around 4 L/s. The bore is
cased with 140rrrrn NB steel casing and has a recorrrrnended continuous
pumping rate of 12 L/s (pumping alone) . However, a 115rrrrn ID
perforated liner has been set inside the casing limiting the size
of pu.~p with which the bore can be equipped and thereby limiting
the rate at which the bore can be pu..-nped.
Table 5.3 shows current and recommended Plli~ping rates and pump
settings.
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 37 of 70.
. Tll.BLE 5 . 3 PUMPING Rl\.TES AND PUMP SETTINGS
RN
5955
6035
21481
PUMPING RATE L/s
6.5
4
7.3
CURRENT
PUMP SETTING (m)
48.7
36.6
36. 0
PUMPING RATE L/s
12
4
11
RECOMMENDED
Pu"MP SETTING(m)
!;8.7
36.6
36.0
The only bore comprehensively pump tested was 21481. Bores 5955
and 6035 should be retested using 24 hour constant rate tests and
multirate test to enable confident predictions of performance.
Water is trarcsferred from the borefield to the community storage
tanks by 3900m of lOOmm NB rising main. The main is generally
constructed of PVC below ground, but has several sections of
galvanised steel with victaulic coupling above ground on concrete
plinths along sections where hard rock outcrops occur. It is
thought that by increasing the diameter of the mains, friction
losses would drop thereby increasing the yields from the pu_~ped
bores.
Water is also obtained from the Roper River by way of three
submersible pumps housed in 150mm diameter pipe. River water is
used mainly as a backup supply or to top up the tanks. The river
supplies about 15% of Ngukurr's domestic water, with only one or
two of the river pumps pumping for about twelve hours a day.
The presence of algae during low flows and turbidity during high
flows, decreases the quality of the river water. In 1981 a slow
sand filter was commissioned to remove algae and suspended
solids, however, difficulties were experienced due to filter
clogging and the plant was abandoned. The seasonal variation in
the quality of river water also is a problei""Tl. However, it is
acceptable for most of the year, only rising above acceptable
levels towards the end of the dry season. S~bsequently, it is
considered the best practice to only use river water when the
borefield is unable to meet demand and when turbidity and saline
levels are acceptable (readily determined by sight and taste by
the operator) .
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 38 of 70.
The river pumps discharge to the community distribution storage
tanks by way of a 150mm NB galvanised steel pipeline with screwed
joints above ground on concrete plinths. Water from both the
river and borefield is pumped to a 450 kL ground level tank.
Water is transferred from the ground level storage to a 90 kL
elevated tank by two electric motor driven centrifugal pumps.
A chlorination dosing plant treats water as it is transferred
from ground level to elevated storage.
Water gravitates to the community by way of a 150mm NB PVC main.
Water is reticulated through the community in lOOmm NB and 150mm
NB PVC mains. 54 Millcock type fire hydrants are provided at
approximately 90m centres along the mains.
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 39 of 70.
6 • CONCLUSIONS
Ngukurr's domestic
approximately 85%
water supply is currently co.cr~osed of
groundwater and 15% river water. The
groundwater is supplied from three production bores; these are
RN 5955, 6035 (used as a standby) and 21481. The aquifer is at
the basal contact of the Yalwarra Volcanic Member with the
underlying sediments of the Kookaburra Creek Formation.
Current extraction rates show that a continuous yield of 11 L/s
appears to be sustainable for the borefield. The water quality
of the groundwater is marginal, with the waters having high
hardness and NaCl levels. Water quality from Roper River is
variable, depending on the time of year.
gone above acceptable limits only towards
Salinity levels have
the end of some years.
However, turbidity can be a problem and treatment is sometimes
needed for extended periods throughout each year.
The current supply rates for the production bores are 6.5 L/s for
5955 and 7.3 L/s for 21481 when puzrrping in conjunction with 5955.
The rate for 21481 increases to approximately 11 L/s when it is
pumping by itself (due to reduced friction losses). Bore 6035
is capable of supplying 4 L/s, however, contamination has
occurred due to the spillage of diesel down the borehole.
Therefore, 6035 should not be used until the extent of the
contamination has been determined and any subsequent clean up
work has been undertaken.
Water from Roper River is supplied via three axial flow pumps.
Insufficient data exists to accurately describe the properties
of the river water. Until further work has been undertaken and
adequate means of treating the river water (physical and
chemical J are being utilised, usage of the groundwater source for
most of the year will be required.
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 40 of 70.
7. RECOMMENDATIONS
It is recommended that:
( i) The pumping rate and pumg settings be in accordance
with table 5. 3. However, the regime of borefield
extraction should not exceed 11 L/s until such time
that work leading to an assessment of the sustainable
yield of the resource indicates that this is feasible.
(ii) Production bores 5955 and 6035 be retested to
ascertain the performance characteristics.
(iii) Water quality analysis be taken from bores Rl~'s 5955,
6035, and 21481 biannually.
(iv) Section profiling and sampling of the river from Roper
Bar to Ngukurr in October be undertaken. This will
determine where the low salinity water is coming from
at this time of the year and also identify a more
suitable site for the location of the pump intake.
(v) A provision for a shut-off system for the river pumps
dependent on salinity levels should be incorporated.
(vi) Further work be undertaken to determine the extent of
the contamination due to the spilling of diesel down
RN 6035 and what cleanup work is necessary.
(vii)
(viii)
A rain gauge be set up and daily rainfall readings
taken.
All existing bores be surveyed to a common datum.
(ix) A water use study be undertaken to determine the
causes of the high consumption rate. Efficient water
usage practices should be encouraged and consumption
and wastage reduced where possible.
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 41 of 70.
Water Resources Division
PAWA
B Smith
Kinhill Stearns, 1985
Pietsch, B.A. et al 1991
8. REFERENCES
Roper River 1980 and 1986 Water
Quality Surveys
"Water Supply Investigations,
Roper River, Yugul Cartle Co."
Registry File No 4/68/36, Parts I
and II.
"Badaarka Surface Water Sources",
Water Resources Division, PAWA, NT.
"Bamyili, Bulman, Lajamanu,
Ngukurr, Investigation for Water
and Sewerage Service".
"McArthur River Region 1: 100 000
Geological Map Series" , Northern
Territory
Explanatory
Geological Survey,
Notes. 6065-6165.
National Health and Medical Research Council and Australian Water
Resources Council G . d 1 . f' D . k . '"' . " ui e ines _or rin ing ,,ater in
Australia, 1987". Australian
Publishing Service, Canberra.
Northern Teritory Government, 1991
Wallis, D. 1984
"Interim Guidelines on the level
of Essential Services to
Aboriginal Communities".
"Tecli.nical Report on the Status
of Ngukurr Water Supply", Water
Resources Division, PAWA, NT.
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 42 of 70.
APPENDIX A
NGUKORR GROUNDWATER INVESTIGATIONS
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 43 of 70.
APPENDIX A
1. Drilling
Various groundwater investigations have been conducted around
Ngukurr. Drilling programmes were undertaken in 19 61, 19 63,
1967, 1978 and 1982 and have resulted in a total of 27 bores
being drilled, including three production bores.
The first attempt to locate groundwater supplies around Ngukurr
was carried out in September 1961, in which bores 2725 to 2743
were drilled. All were dry holes, except 2743, which yielded
0.25 L/s, however, the water was high in NaCl and was
unacceptable for drinking purposes.
In September 1962, four bores were drilled in the flood plain to
the east of Ngukurr. The bores, 4219, 4098, 4099 and 4100,
produced yields ranging from 0.25 L/s to 4.5 L/s, however, high
NaCl content made the water unacceptable for conslli~ption.
Further drilling in November 1967, approximately 3.5km north
northwest of Ngukurr, resulted in two bores - 5955 and 6035 - in
close proximity to each other. The bores had estiwated yields
of 12.5 L/s when pu..-rrped separately and produced water suitable
for drinking. Both bores were subsequently constructed as
production bores.
From May to June 1972, bores 7868, 7869 and 7870 were drilled.
Bores 7868 and 7869, which were approximately 12km and 21km north
of Ngukurr respectively, were dry, whilst bore 7870, located on
the flood plain to the east of the community, produced a yield
of 2.5 L/s. However, the water was not suitable for drinking
purposes.
A further drilling programme was undertaken in September 1978.
The drilling resulted in bore 9325 which produced 0.6 L/s of
potable water, as well as two dry bores, 9323 and 9234.
In July 1982 a further drilling programme was conducted in which
bores 21503 to 21507 and bore 21481 were drilled. Bores 21503,
21504, 21505 and 21506 were drilled in the vicinity of the
Showell Creek fault. Bores 21503, 21505 and 21506 produced
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 44 of 70.
yields of potable water of 1.5, 1.3 and 0.8 L/s respectively,
whilst bores 21504 and 21507 were dry holes. Bore 21481, which
was drilled as a replaca~ent for production bore 6035, produced
a yield of 30 L/s when pumping alone and was constructed as a
production bore.
The Ngukurr borefield currently comprises bores 5955, 6035 and
21481, which are all located within lOOm of one another in a
small area 3.5km north-northwest of the community. All other
bores surrounding Ngukurr have either no water, water of an
inferior quality or water of insufficient quantity.
Table A1 provides interpretive logs of all bore holes drilled
around Ngukurr.
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 45 of 70.
TABLE Al LITHOLOGICAL LOGS
REG'D NO
2735
2736
2737
2738
2739
TOTAL DEPTH(m)
17.4
3.8
31.7
10.2
12.8
INTERVAL (m)
0.0 - 3.4 3.4 - 9.1 9.1 - 11.6
11.6 - 12.2
12.2 - 15.5 15.5 - 16.5 16.5 - 16.8 16.8 - 17.3 17.3 - 17.4
0.0 - 0.6 0.6 - 3.7
3.7 - 3.8
0.0 - 2.4 2.4 - 3.7
3.7 - 5.6 5.6 - 31.7
0.0 - 3.7 3.7 - 6.1
6.1 - 7.0 7.0 - 7.6 7.6 - 10.1
10.1 - 10.2
0.0 - 3.7
3.7 - 9.8
9.8 - 10.4
10.4 - 12.4
12.4 - 12.7 12.7 - 12.8
LITHOLOGICAL DESC..."R.IPTION
COMMENTS
Brown clay No water Fine drift clay struck Coarse sand & gravel Grey & yellow clay with gravel Grey clay Sand & silt Grey clay Grey silty clay Fractured quartzite too hard to drill
Sandy top soil No water Ironstone conglom- struck erate Hard conglomerate, unable to drill further
Yellow clay & silt Seepage Conglomerate & boulder water worn gravel Clay Red brown shale with odd pieces of grey shale & yellow mudstone. Drilling became harder with depth.
Yellow clay No water Grey sandy clay struck with ironstone gravel Red brown shale Grey & red brown shale Very hard red brown shale Undrillable strata
Solid red sandy No water clay, soft yellow struck clay with calcareous sandstone pebbles & boulders Fine yellow drift sand & weathered sandstone boulders Coarse sand - white & yellow Coarse sand & gravel, some white & yellow clay Boulders Hard fractured quartzite
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 46 of 70.
REG'D NO
2740
2741
2742
2743
4098
4099
TOTAL DEPTH(m)
10.6
16.1
11.8
21.6
85.3
38.1
INTERVAL (m)
0.0 - 0.9 0.9 - 4.9
4.9 - 10.6
0.0 - 4.9 4.9 - 7.3
7.3 - 8.5 8.5 - 9.1 9.1 - 9.8 9.8 - 16.1
0.0 - 2.7 2.7 - 4.6 4.6 - 9.8
9.8 - 11.8
0.0 - 9.1
9.1 - 10.7 10.7 - 17.4
17.4 - 18.0 18.0 - 19.2 19.2 - 21.6
0.0 - 30.5
30.5 - 32.0 32.0 - 33.5 33.5 - 36.6 36.6 - 41.1
41.1 - 57.9 57.9 - 79.3 79.3 - 85.3
0.0 - 27.4
27.4 - 30.5
30.5 - 32.0 32.0 - 35.1
LITHOLOGICAL DESCRIPTION
COMMENTS
Solid yellow clay No water Grey, yellow & pink clay White & brown rubble basalt quartzite, jasper & clay too hard to drill at 10.6m
Red sandy clay No water Fine yellow drift sand Sand with some clay Coarse sand & gravel Boulders & broken rock Hard & soft bands of porcellanite with odd pieces of quartzite & jasper
Black & grey clay No water struck
& chocolate Red clay Blue grey clay Sand seam at 9.lm Red brown shale, hard at ll.8m no penetration
too
Grey yellow & chocolate 0.25 L/s
clay, some silt at 19 .2m Sand & silt, some clay Grey & chocolate clay, some silt Sand seams Grey clay Boulders & sand, water worn gravel
Reddish brown Dolerite 0.5 L/s Dolerite & brown shale Dolerite Limestone & red shale Reddish brown shale, calcareous shale, limestone & dolerite Dolerite
li:µ:tab le
from 85m uq:otable
Dolerite & fawn limestone Fawn & white limestone
Dolerite with brown grey clays, calcareous clay Pink, cream & fawn limestone Green & brown Dolerite Yellowish-brown limestone
4. 5 & L/s from 33m
unpot able
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 47 of 70.
REG'D NO
TOTAL DEPTH(m)
4099 cont'd
4100 19.4
4219 44.0
5955 57. 9
6035 50.6
INTERVAL (m)
35.1 - 38.1
0.0 - 3.0 3.0 - 9.1
9.1 - 11.0
11.0 - 11.6
11.6 - 12.2 12.2 - 13.7
13.7 - 15.2 15.2 - 19.4
0.0 - 1.5 1.5 - 22.9
22.9 - 36.6 36.6 - 38.1 38.1 - 39. 7 39.7 - 41.2 41.2 - 42.7 42.7 - 44. 0
0.0 - 3.1 3.1 - 12.2
12.2 - 13.7 13.7 - 18.3
18.3 - 21..3 21.3 - 41.. 2 41.2 - 48.8 48.8 - 54.9 54.9 - 57.9
0. 0 - 3.0
3.0 - 12.2
12.2 - 13.7
13.7 - 18.3
LITHOLOGICAL DESCRIPTION
COMMENTS
Yellowish-brown & fawn limestone
Brown clay Fine brown sand Brown sand & grey clay, laterite mudstone Laterite, siliceous oolitic material, black to grey clayey sandstone Pink quartzite Brown siltstone & sandstone, clay Brown sandstone Black & fawn banded siltstone & fine brown sandstone
Yellow clay Feldspathic sandstone with purple siltstone Reddish brown Dolerite Dolerite & limestone Fawn limestone
0.2 L/s
from 17m unp;:table
0 . 2 5 L I s from 37m unp;:table
Green & red calcareous Fawn & grey limestone Reddish brown Dolerite
shale
Soil & basalt Basalt Brown shale Shale with hard basalt ledges No returns Clay & loose basalt Loose basalt
Production yielding 12.5 L/s
Firm to hard basalt Slightly softer basalt
Top soil: red clay- Productey, sandy fragments, ion bore very weathered red yield-basalt ing Basalt: soft, red, 12.5 L/s very weathered. Also present is sandstone (4.5 - 6.lm) fine quartz sand in a 20% clayey ferruginous matrix; claystone (7.6 - 9.lm) white, sandstone (9.1 - 10.7m) red & yellow & chert; claystone (10.6-12.2m) red Silty clay, red, containing red & yellow siltstone Sandy shale - sandstones red
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 48 of 70.
REG'D NO
TOTAL DEPTH(m)
6035 cont'd
7868 106.7
7869 122. 0
7870 48.8
9323 15.0
9324 35.0
9325 31.5
INTERVAL (m)
18.3 - 22.9
22.9 - 27.4
27.4 - 32.0
32.0 - 37.1
37.1 - 38.1 38.1 - 39.6
39.6 - 41.1 41.1 - 44.2
44.2 - 50.6
0.0 - 24.4 24.4 -106.7
0.0 - 0.9 0.9 -109.7
109.7 -122.0
0.0 - 9.1 9.1 - 48.8
0.0 - 1.0 1.0 - 4.0 4.0 - 15.0
0.0 - 9.0
9.0 - 12.0
12.0 - 22.0 22.0 - 30.0 30.0 - 32.0 32.0 - 35.0
0.0 - 8.0 8.0 - 13.0
13.0 - 16.0
16.0 - 19.0
19.0 - 20.0
LITHOLOGICAL DESCRIPTION
CC1YJMEN'TS
Basalt, weathered, has chlorite vesicles, pink, red & grey. Also present - red sandstone & siltstone & quartz Basalt: red/grey, red siltstone & sandstone, also pink-green feldspathic sandstone Basalt: red, red comglomerate sandstone & red siltstone Red weathered basalt & red siltstone Red fresh basalt Blends of impure chalcedonic silica. Also quartz & a yellow sandstone containing dendritic Mn02 No sample available Yellow impure sandstone bands, also some yellow grey banded chalcedonic silica Pale pink & white crystalline limestone. Yellow sandstone & yellow-grey chalcedonic silica
Sandy clay Shale
Sand Shale & sandstone Red shale
Clay Siltstone
Clay & siltstone Red siltstone Grey siltstone
No water struck
No water struck
2.5 L/s from 44m unpotable
No water struck
Brown clay & mud- No water stone siltstone struck Brown clay, siltstone, mudstone & limestone Grey siltstone & clay Grey siltstone & limestone Grey siltstone Grey siltstone & limestone
Brown clay & gravel Brown clay, gravel from mudstone
0.6 L/s from 23m
Clay, gravel, mudstone & limestone Brown siltstone & mud-stone Brown siltstone & limestone
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 49 of 70.
REG'D NO
TOTAL DEPTH(m)
9325 cont'd
21503 80.0
21504 27.0
21505 54.0
21506 43.0
21507 49.0
2148l 49.0
INTERVAL (m)
20.0 - 23.0 23.0 - 26.0
26.0 - 27.0 27.0 - 28.0 28.0 - 3l.O
3l.O - 3l.5
0.0 - 3.0 3.0 - 9.0 9.0 - 30.0
30.0 - 57.0
57.0 - 80.0
0.0 - 3.0 3.0 - 27.0
0.0 - 3.0
3.0 - 54.0
0.0 - 6.0 6.0 - 30.0
30.0 - 43.0
0.0 - 12.0
12.0 - 18.0
18.0 - 49.0
0.0 - 36.0 36.0 - 43.0
43.0 - 49.0
LITHOLOGICAL DESCRIPTION
CCMJJENTS
Grey siltstone & mudstone Grey & brown siltstone & limestone Grey & brown siltstone Mudstone & limestone Grey & brown siltstone & muds tone Brown siltstone
Clay Gravelly clay Grey/greenish silicif ied fine sandstone
l.5 L/s from 76m
Pink silicified sandstone
fine
Black silicified brown silicified
Clay Grey silicified fine to medium sandstone, minor green micaceous siltstone
siltstone, sandstone
No water struck Hole abandoned Drill bit broke off
Clay, sand & chert 1.3 L/s chips from 24m Dark grey massive chert
Clay 0.8 L/s Sandy clay from 24m Weathered intermediate volcanic - andesite
Gravelly clay, siltstone sandstone & limestone Yellow sandstone & pink siltstone/shale Dark grey limestone
Clay & gravel Broken basalt & sandy clay Gravelly quartz
No water struck
Production bore
15 L/s
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 50 of 70.
2. Test Pumping
Bore 21481 was the only bore comprehensively test pumped. This
entailed a 24 hour constant
1982 at a rate of 33 L/s.
discharge test carried out on 2 July
At 1400 minutes the bore forked and
maintained a constant discharge of 30 L/s until completion (1440
minutes). One observation bore (6035, 55m to the east) was
simultaneously monitored. No residual readings were taken.
On 5 July 1982 a step drawdown test consisting of three rates each
of 100 minutes duration was performed on 21481. The rates were 27,
30 and 33 L/s.
Technical R
eport WR
D92041
View
ed at 15:07:57 on 29/07/2010P
age 51 of 70.
,, -· cc • )> I\) -f.\I -
s
6
I/)
~ 7 ~ ., E
z ~ 0 CJ ~ ~ 8 0
9
x
x
x
10 1
PUMPED BORE 21481
DISCHARGE 33l./s
DATE 2/7/82
x
X Xx x
x v ---
10
x x x xx x
x x
"x x x x
x x x
x xx
'X x x ~-PUMPING ON FORK
AT 30 Lis 100 1000 10000
TIME (minutes)
CONSTANT DISCHARGE TEST 21481
Technical R
eport WR
D92041
View
ed at 15:07:57 on 29/07/2010P
age 52 of 70.
,, -· (Q • )> I\) -CT --
z 3 0 0 3 <( a: 0
10
1.0
0. 1
0,0 1
PUMPED BORE 21481
OBSERVATION BORE 6035
DISCllARGE 331./s DATE 2/7 /82
10
;<xx xx '
)(
x
x
--
x
'I':
100 1000 10000 TIME (minutes!
CONST ANT DISCHARGE TEST
Technical R
eport WR
D92041
View
ed at 15:07:57 on 29/07/2010P
age 53 of 70.
,, -· (Q • )> I\) -0 -
z: s 0 0 s
5
6
"/
~ 8 0
9
10
x
x
1
PUMPED BORE 21481
DATE 517/82
x-x-x---x-x I'~ A J< --,; ,.
·-
10
Q - 27 L/s ,. , ,.
> Q - 30 L/s
~
x x
x x ~ ~
Q - 33 L/s
\
' 100
TIME (minutes) 1000 10000
STEP ORA WDOWN TEST 21481
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 54 of 70.
APPENDIX B
BORE CONSTRUCTION
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 55 of 70.
Bore Construction
Details of the construction of the bores drilled in the Ngukurr
area are given in Table Bl.
Three production bores were drilled in two separate investigations
(two in the 1967 investigation and one in the 1982 investigation).
These three bores are within lOOm of one another, approximately
3.5km north-northwest of Ngukurr, and have all been constructed in
the Kookaburra Creek Formation at the contact of the Yalwarra
Volcanic Member with the underlying sediments.
Investigation drilling indicates that this is the only area that
yields potable water in the immediate vicinity.
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 56 of 70.
BORE RN
2735 2736 2737 2738 2739 2740 2741 2742 2743 4098
4099 4100 4219 5955
6035
7868 7869 7870
9323 9324 9325 21503 21504 21505 21506 21507 21481
TABLE B1
COMPLETION DATE
23/09/61 25/09/61 28/09/61 29/09/61 02/10/61 03/10/61 04/10/61 05/10/61 06/10/61 10/10/63
14/10/63 17/10/63 27 /09/63 16/11/67
20/11/67
11/06/72 28/05/72 05/06/72
28/09/78 05/10/78 11/10/78 12/06/82 13/06/82 14/06/82 14/06/82 16/06/82 15/06/82
BORE CONSTRUCTION DETAILS
DEPTH DRILLED (m)
17.4 3.8
31.7 10.2 12. 8 10.6 16.2 11.7 21.6 85.3
38.1 19.4 43. 9 57.9
50.6
106.7 121. 9
48.8
15.0 35.0 31.5 80.0 27.0 54.0 43.0 43.0 49.0
CASING DTAILS
STATUS
None installed " " " " " " " "
0-5.0m 140mm casing & 140mm shoe Casing retrieved
" None installed 0-51.6m 140mm casing Production 140mm casing shoe Bore 0-24. Sm 140mm ID Production casing Bore 24.5-37.6m 140mm ID perforated 0-29.4m 115mm ID liner 29.4-37.6m 115mm ID perforated liner 0-22.9m 203mm casing None installed 0-18.3m 203mm casing 0-44.Sm 152mm casing None installed
" "
0-2m 203mm collar None installed 0-2m 203mm collar None installed
" 0-36m 2 03mm ID Production steel casing Bore 36-49m 203mm ID perforated steel casing
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 57 of 70.
APPENDIX C
BORE COMPLETION REPORTS
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 58 of 70.
BORE COMPLETION REPORT
1. Introduction
A number of groundwater investigations have been undertaken at Ngukurr.
These have resulted in three production bores, 5955, 6035 (drilled in
1967) and 21481 (drilled in 1982).
2. Geology
The production bores have been constructed in the Kookaburra Creek
Formation at the contact of the Yalwarra Volcanic Member and the
underlying sediments.
12 L/s.
3. Water Quality
Individual bores are capable of yielding up to
The water from the groundwater source has high hardness (450-550 mg/L)
and high NaCl (300-500 mg/L) levels. These are considered marginal in
terms of drinking water standards.
The hardness is due to the limestones/dolomites of the Kookaburra Creek
Formation~
4. Barefield Performance
Three main factors contribute to drawdown in all production bores :
( i)
(ii)
(iii)
Well lossess occurring in the first ten minutes of pu.~ping.
Aquifer losses, and
Seasonal water level decline of 3m a year (assumed).
The borefield to date has peformed at a rate equating to 14 L/s.
However, the sustainable yield of the aquifer has not yet been assessed
and this work should be undertaken before the yield from the boref ield
is increased.
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 59 of 70.
WATER RESOURCES DIVISION
TEST REPORT - BORE RN. 59 5 5
Bore Location: NGUKURR. Map: URAPUNGA 1:100,000 Sheet: 5868. Grid Reference: 696 - 740.
Client Purpose
AES. COMMUNITY.
RECOMMENDATION. Pumping Rate: 12 L/s. Pump Setting: 48.7 m. For alternative pumping rates or settings contact Water Resources. General recommendations are on the reverse side. Sasco House, In all correspondence please quote bore RN 5955. Darwin NT.
************************** .. ""**-.':******** .. ':** .. '::*********1:*-.':*-.':-.'::**~':**"i<**-:~*i<********i:*
BORE DATA. Finished depth: 57.9 m. Completion Date: 16.11.67. Standing Water Level: 30.4 m on 9. 10.68. Construction details:
Test Date: Test Rate:
Test Duration:
Interva 1. Description.
0 -51. 8 -
51. 8 m 57.9 m
140 mm ID 140 mm
steel casing. open hole.
Notes: 1. Top of casing as constructed was 0.3 m above ground. 2. All depths are measured from natural ground level.
9.10.68. 12 L/ s.
100 mins.
3. Test rates are not indicative of safe long term pumping rates.
WARNING: MINIMUM INTERNAL BORE DIAMETER IS 140 mm. MINIMUM INTERNAL BORE DIA..'lETER TO RECOMMENDED PUMP SETTING IS 140 mm.
COMMENTS.
1. The above recommendations are based on previous testing and use and assume hydrological conditions remain constant.
2. Provision to monitor water levels and obtain water samples should be incorporated in the headworks.
3. The pumping rate is for bore pumping on its own.
*********************************~'(i<*****1«•'::*******"'-**'k't.:."/.:."'l.:.~'(·k*~':*~'::***"k****'l~*1~**
WATER ANALYSIS. No. 82/1353.
Prepared by: P Tyson. 20/7/93.
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 60 of 70.
RECOMMENDATIONS FOR FINISHING, OPERATING AND PROTECTING GROUNDWATER BORES.
Attention to the following points will ensure a long and safe life for the bore supply and help prevent pollution of the groundwater resource.
1. Construct a concrete apron around the bore head to prevent surface flow, seepage and weste from entering the bore.
2. Seal the space between the casing and pump equipment to prevent entry of vermin, dirt and pollutants.
3. Maintain pumping equipment i~ good order to prevent pollution. Prevent spillage of fuel and oil on the ground around the bore. Store fertilizer and other chemicals at least 50 m. away.
4. Keep stock away from the bore head. bore.
Discourage domestic ac~ivity at the
5. Pumping the bore at higher than recommended rates may fork the bore leading to instability or pum~ mai~~enance problems. Seek the professional advice of an hydrogeologist or groundwater engineer.
6. !f the bore is no longer requi~ed, the casing is to be removed or securely capped and the bore backfilled wi:h clayey material. A cement plug may be required in some instances.
I~ ADDITION, please ensure that ~he BORE IDENTIFICATION TAG is retained securely a~ all times. The registered bore number ia Water Resources Division's only reference to the scientific and engineering data on this bore and hence important to WE.D's further advice to bore owners.
30RE LOCATION ~.A?.
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 61 of 70.
DEPTH BORE GRAPHIC STRATA AQUIFERS (ml CONSTRUCTION LOG DESCRIPTION (WATER STRUCKl
0.3m
0 L,,;:
0 •{.f.i;:!~~ Soil and basalt \~f?-1:(;.~t
- ~R'.!*~;{. I-
-;,-. ..:-: ... -~ ":t..:-~::'.t'<.
5- •{.G.-;"1~~} I- 5 ~i,!~:r~.;,:t :;:? ... :: ... _:;::-\~}},~I!~ Basalt I-- ·~YJ~~ {~"'}~@
10 - ~.t~7C* 1-10 G;'>'l'-{if{. ~fi~k.s; " - "'' - =~ Brown shale I-
15 - ~~ '-15 =~ =~ Shale with hard basalt ledges =~ - :;;:
I-- -=-----=-
20- "" No returns 1-20 :z u:i .. '''.' «'. <.''.' - (.) .. ' .. ' I-
... '' .. -' •••• <.'
LU ..... '
25- LU ..... ' 1-25 ,_ ... '.' u:i .. ' ...
. . . ''. - Cl '. '.' I-
.. ' ... '
E ... ' .. ' ... ' .. ' LL SWL 30.4m 30- E '. ' .. ' Clay and loose basalt 1-30
0 .. '' '.' 9/10/68 :;!: .. '''.' .. '''.' - • <., •• ' I-•• '< ••• . . . . . . . . '.' .. '
35- .. '' ... I- 35 • . <'.'' ..... ' .. ' .. '
- .. ''.' I-... ' .. • • • < •• ' .. ' .. '
40- .. ''.'' I- 40 ... '' .. -fe::::t~.:r::
, ... - ...... -(.:! ... - w -tG~t'l,::~ I-
0 -~!efE'.'.~ :c -:Yd~f1:7J 45-
u:i Loose basalt -45 '0-{:""-{'"'
"" -i ::::t~.r~ ;.-_~ ... -{:--{•
:z -N:::t'1~'J' - u:i -7-?!e~tx -
«'. .!~-(;;{~
(.) .i.-j;':.i, ... 50-
-M' .. t~:M -50 -~"'r~J'.~
I -~}t;;_t.;, - -?frtft~ ... -
-~il~~ Firm to hard basalt 55- -~1~"iZ """ 12.5 L/s -55 ,.._-{;"-{'"
-ffc:LVt_...j\1 ~""-:1--.".'" -"J<';~ci...tr
- ~{~:{~ -
COMPOSITE LOG OF BORE 5955
Fig. C1{a)
Technical R
eport WR
D92041
View
ed at 15:07:57 on 29/07/2010P
age 62 of 70.
,, (Q • () ...... -CT --
0
2
4
6
(/)
~ 8 ~
" E
z ;:;: 10
0 a 5 <( 12 Cl'. 0
14
16
-
DRAWDOWN VITHOUT
--~--"-----·---------------
AVAILABLE Di AWDOWN 20.4m !PUMP ET AT ASS JMED: SEASONAL DRAWD lWN 0.3m 1 MONTH (DRY SEASON ( NL YI
SWL 28.3m 100 1000 10000
TIME (minutes)
' I I I I I I I I
' I I I
SEASONJ.\L...C~G I
-INE-Pl:JM/O/ • ~ I\ I '12 Lis ----- -. , __ I -- I ....
'· DRAWCJOWN ',AT 1_f L/s +
'SE~SONAL ',D CLINE ,,
..,-. -----I I I I
I I I I
I I I I
I I I I
48.7ml I I I I I
100000 1 YEAR 1000000
PUMPING CURVE RN 5955
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 63 of 70.
WATER RESOURCES DIVISION
TEST REPORT - BORE RN. 6 0 3 5
Bore Location~ NGUKURR. Map: URAPUNGA 1:100,000 Sheet: 5868. Grid Reference: 696 - 740.
Client. Purpose
AES. COMMUNITY.
*****************************};:*************t.:;~~**~"*'f.::*i'-J.::*i:**1<*-1<'k*i:****1:*-i:i.:;*'f.::*'i.:;~'(**
RECOMMENDATION. Pumping Ra~e: 4 L/s, Pump Setting: 36. 6 m. For alternative pumping rates or settings contact General recommendations are on the reverse side. In all correspondence please quote bore RN 6035.
Water Resources. Sasco House, Darwin NT.
BORE DATA. Finished depth: 50.6 m Completion Date: Standing Water Level: 29 m on 16.9.68. Construction details:
Interval.
0 - 24.5 m 140 mm
13.12.67. Test Date: Test Rate:
Test Duration:
Description.
ID steel casing.
16.9.68. 9. 4 L/ s.
7 hrs.
24. 5 3 7. 6 m 140 mm ID perforated steel casing. 0 - 29.4 m 115 mm ID steel liner.
29.4 - 37.6 m 115 mm ID perforated liner. 37.6 45.7 m 140 mm open hole. 45.7 50.6 m 120 mm open hole.
Notes: 1. Top of casing as constructed was 0.4 m above ground. 2. All depths are measured from natural ground level. 3. Test rates are not indicative of safe long term pumping rates.
WAR..~ING: MINIMUM INTERNAL BORE DIAMETER IS 115 mm. MINIMUM INTERNAL BORE DIAMETER TO RECOMMENDED PUMP SETTING IS 115 mm.
COMMENTS.
1. The above recommendations assume hydrological conditions remain constant.
2. Bore has been relined with a 115 mm steel liner.
3. Note pump setting is inside the perforated liner.
4. The bore is currently equipped with a pump with a capacity of 4 L/s.
5. The maximum pumping rate is based on the limitation of the liner~s internal diameter.
6. Recommended rate is for bore pumping on its own.
************************************)"'l::*******)':*****}':*****)':**~'::'!::*****~':**-l<l~~':**i::
WATER ANALYSIS. No. 82/1344.
Prepared by: P Tyson. 20.7.93.
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 64 of 70.
RECOMMENDATIONS FOR FINISHING, OPERATING AND ?ROTECT!NG GROUNDWATER 30RES.
At~entior. t:o t.~e :cllowing Pcints will ensure a lo~g and sa:e :i:e SL!;"pl31 .a:ld. hel~ pre,le::t: :;iol~ucion. c:: thf: g:r::n.z.n.C..-;.;a.te!" :-escurce.
fer t:he be:- e
" .
.'.:..
Cccst:=~c= a ==~c=e:el a;ron aroucd :~e bore hea~ t:: see?ag~ an~ ~as~~ ~=km e:::.~ering t:~e bc=e.
a::C. equi:;::ne:::.:
:n gooC crier :o prevent: s~illa&e cf :~el a::d oil or. the grounC arcu::d t:he bore. and other che=~ca:s a: leas: 50 m. awey,
Kee? st:cck away ==o~ t:~e bcre he~d. :icre.
su?."face.
e ,..i""-·· .. ..... -~~
?t~::i.pi.:ig t:!:e ~or~ .a: hig:her :.=ia:i re~cc.menC.ed :-at:es :nay f:::':<. t:ie. bar~
of
:eadi~g t:= i~st:~b::::y er pu~p main:~nance prco~e~s. Seek :~e ;r=::ss~o~a: aCvice of an ~yd=ogeclogist: er gro~nd~a~~r engineer.
::i. !t :::e ~c!"2 is ::c :o:-:.g~r :-equ.i::-ed, :.!"~e c.asi::g :.s !"" .... be :-emcved or sec"..:.:-e:.y ca~;ed ~cc =~~ =c~e backf~lled w~~~ clayey m~:e=ia~. A ce~e~c ~l~g ~ay Ce :e!:.uirec. .:..n sc~e i~s"Ca::.ces.
' . . . . o~ c~~s :c:e ano ne~ce
"·;-· ;-:-~
: .... _;?-.:.:l~~- ~~-:! '
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 65 of 70.
DEPTH BORE GRAPHIC STRATA AQUIFERS (ml CONSTRUCTION LOG DESCRIPTION (WATER STRUCK)
0.4m
0 ~
0 ...... Topsoil, clay and weathered basalt . . . . . . - e'~ml.!'!.. ~
elW~{.
5- e~$77~~ f- 5
c:> e~~.;...;.rer, :z i§!..!.~<tr,~ Basalt, sol! red minor sandstone <Z>
_..:-~.._.::,,._..:-- t.!~~f.~£~ -<: er274~£ (_)
10 - --' er2~~{: -10 UJ tr2~~ UJ I- e~-;J;<tr,
- "' a: -- , .. --- f-LU Siltstone and clay 0 z _, -~ 15 - E ~- f-15
"" =--E z =-- Sandy shale and sandstone red =--0 <: ~~~
- .... _, E -=::; -l co c:> 0
:(,~&!Z~ :z ~!ill~; 20 - (/.; - 20 <: E ~!i?""J~} (_) E Z!eiJY,~ - "' ---~11..f.''r-:'\ -_, - l,~ct~:::. UJ :r!t't]Z; LU ~ ~
1-0 ~f<..!.----1 25- II II l'..'-~ -25 <r.l LU ~a:~? I-
O<: II II w--{., ... - Basalt, weathered siltstone and sandstone -a: ..!t!~fo::.' - EO II II rti,~7?,} -Eu... 1&f.7J} '1- SWL 29.0m oCC II I I I I I II :<l~!..!.>-:1 16/9/68 30- .... L .::.:...:;,:~..:'..::- -30
II I I I I I II ~-'t':''•' .::,.. __ {~..:'..:: ~!---,.,_\
- II I I I I I II .. -,,..?.r..:'..:: -::h:~~'N::.'
II I I I 11 II ~}l~70} 35 - II 11 11 II
0;<z;rJ:-jZ;1 - 35 ---"t{{.'"-.._I~-/.,:>
• N.
I I 11 I ;;'~'<:-7"/!:' Fresh basalt -- ...... '' .... vvv 12.5 L/s . . . ' ..
cc ...... 40- UJ
...... Chalcedonic silica and sandstone - 40 ...... zo ..... '
:J~ ...... . . . . . . . . . . . ' - o< ...... --a: ......
EO ...... Eii:
...... 45- ...... -45 . . . . . . .,., UJ ...... Crystalline limestone, yellow sandstone and ::= "- ...... . . . . . .
- ...... chalcedonic silica -...... . . . . . . . . . . . . . . . . . . 50 -
. . . . . -50
- -
55- -55
- -
COMPOSITE LOG OF BORE 6035 I Fig. C2(a)
Technical R
eport WR
D92041
View
ed at 15:07:57 on 29/07/2010P
age 66 of 70.
.,, -· (Q • () l\) -er -
0
2
4
6
"' ~ 8 -" E
z ;;: 10
0 0 5 <( 12 0: 0
14
16
18
_______ .. ______
' DRAWDOWN Vi ITHOUT
I SEASONAL DECL NE PUMPING I -- AT 4 Lis ------- I ...... I ...
'-..,DRAWD{:JWN ' AT 4 1 L/s +
',,,SE8SONAL ',DIECLINE ,,
~ I ' I I I I I I
,_ ______ 9"1!!!- 8._V.AIL(l~ ].!,; ....QElA ~QQ_WN _ le.LJ.MP _ ~ ';I _llJ_3_6Jl.roL ______ I --- - - - - - - _,_ - --
I ~·-·
I ASS !MED: SEASONAL DRAWD lWN I 0.3m 'MONTH IDRY SEASON C NL Yl I
SWL 27.2m I
' I I I I ' I I I I
----------·. - --------' I I I I
--·~ - I I I I I
100 1000 10000 100000 1 YEAR 1000000
TIME !minutes)
PUMPING CURVE RN 6035
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 67 of 70.
POWER 'I\ --AND-~ WATER RESOURCES DIVISION
WATER~~ AUTHORITY ~
TEST REPORT- BORE RN. 21481
Bore Location: NGUKURR. Map: URAPUNGA 1:100,000 Sheet: 5868. Grid Reference: 696 - 740.
Client Purpose
RECOHMENDATION. Pumping Rate: 11 L/s. Pump Setting: For alternative pumping rates or settings contact General recommendations are on the reverse side. In all correspondence please quote bore RN 21481.
BORE DATA.
AES. COHMUNITY.
36 m. Water Resources. Sasco House, Darwin NT.
Test Date: 2.7.82. Test Rate: 30 L/s.
Finished depth: 49 m. Completion Date: 15.6.82. Standing Water Level: 28.3 m on 2.7.82. Construction details: Test Duration: 24 hrs.
Interval.
0 -36
36 m 49 m
Description.
203 mm ID 203 mm ID
steel casing. perforated steel casing.
Notes: 1. Top of casing as constructed was 0.8 m above ground. 2. All depths are measured from natural ground level. 3. Test rates are not indicative of safe long term pumping rates.
WARNING: MINIMUM INTERNAL BORE DIAMETER IS 203 mm. MINIMUM INTERNAL BORE DIAMETER TO RECOM!1ENDED PUMP SETTING IS 203 mm.
COMMENTS.
1. The above recommendations are based on previous testing and pumping and assume hydrological conditions remain constant.
2. Provision to monitor water levels and obtain water samples should be incorporated in the bore headworks.
3. The pumping rate of 11 L/s is for bore pumping on its own.
4. Finished depth was 49 m but measured depth on 2.7.82 was 47 m.
WATER ANALYSIS. No. 90/91/0329.
Prepared by: R Setchell. 20.7.93.
Checked by: P Tyson. 20.7.93.
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 68 of 70.
RECOMMENDATIONS FOR FINISRING, OPERATING AND PROTECTING GROUNDWATER BORES.
Attention to the following points will ensure a long and safe life for the bore supply and help prevent pollution of the groundwater resource.
1. Construct a concrete apron around the bore head to prevent surface flow, seepage and waste from en~ering the bore.
2. Seal the space between the casing and pump equipment to prevent entry of ver~in, dirt and pollutants.
3. Maintain pumping equipment in good order to prevent pollution. P~event
spillage of fuel and oil on the ground around the bore. Store fertili2er and other chemicals at least 50 m. away.
4, ~eep stock away from the bore head. Discourage domestic activity at the bore.
5. Pumping the bore at higher than recommended rates may leading to instabili~y or pump maintenance problems. advice of an hydrogeologist or groundwater engineer.
fork the bore Seek the professional
6, If the bore is no longer re~uired, the casing is to be removed or securely capped and the bore backfilled with clayey material. A cement plug ~ay be required in some instances.
!~ ADDITION, please ensure that the BORE IDENTIFICATION TAG is retained securely at all times. The =egistered bore number is Water Resources Division's only reference to the scientific and engineering data on this bore and hence important to WRD's further advice to bore owners.
BORE LOCATION MAP.
Technical Report WRD92041
Viewed at 15:07:57 on 29/07/2010 Page 69 of 70.
DEPTH BORE GRAPHIC STRATA AQUIFERS (ml CONSTRUCTION LOG DESCRIPTION (WATER STRUCKJ
0.8m
0 ~
0 ...... '' ' ... '' .... '' ' ... - -'. ' ... '.' .. ' .. ' ...
5- '.'' .. '' ' ... -s '. ' ... . . '' .. ... ' .. - -.. '' .. ' .. ' .. . ' ....
10 - '.' ... -10 . . . ' .. ' ... '' ' ..... .. . ... ' .. - -'' .... . . . . . .
0 '' ....
15 - :z ...... -15 .... '.
"' ...... <C .... '.
Glay and 9ravel - 0 ...... -.. '''. __, ...... LU '.'.'.
20 - w '.'''. -20 I- . ' .. '. "' ...... . ' ....
- a .. ' ... -... ''. E ... '' . . . . . '.
25 - E ...... -25 ""' ...... = "' ...... ''' .. '
- ... ' .. SWL 28.3m -, ..... _y__
0 ...... 2/7/82 :z . ' ....
30- (f) '' .... -30 . . . . . .
<C ...... 0 ... ' ..
- __, . ''.'. -LU . ''.'. LU
...... . ' .... 35- l-o . ' .. '. -35 '-"w ......
1111111 ol- :,j.71,~~·J -<C - 11111111 a: ~~:Yd'i!~ -
EO
11111111 EU.. r~74y~~ Broken basalt and sandy clay .,., a: ~{.\ .. ~I.,;.-~{. 40-
11111111 =w ~~~c~ 'IVY 7.5 L/s - 40 L]a_ ~{.l~:~~ ;~~~ -~
11111111 i}J.f(rfirJ: - ••• -
11111111 ••••••• ••• 11111111 • • • • 45- ••• Gravelly quartz
-45 •••• 11111111 • ••• ••• ••• - 111111 I • • • • -........
50- - 50
- -
55- -55
- -
COMPOSITE LOG OF BORE 21481
Fig. C3(a) -- __ .....--
Technical R
eport WR
D92041
View
ed at 15:07:57 on 29/07/2010P
age 70 of 70.
"Tl -· (Q •
() (..) -C" -
0
2
4
6
"' ~ 8 -" E
z $ 10
0 0 $ <i: 12 a: 0
14
16
18
,_ _____________
-
2~0
' I I I I I I
DRAWDOWN VITHOUT SEASONAL DEC I
/NE PUMPING AT 111 L/s ----- :'!L--------- I
-- ... DRAwoqwN -',AT 11 1 L/s +
'· SEASONAL ' DEjCLINE
'\ ,, ... 1'
9m AVA/LA LE DRAWDOWN !PUMP ET AT 36m) I ........ __. .. ___________
~- --- -- ____ .. ___ ..... ___ .. _ .. _______ - - --- -------1- - - -
I I
ASS IMED: SEASONAL DRAWD WN I
0 3m/MONTH !DRY SEASO ) I I
SWL 27m I ' I I I I
I I I I
-I I I I
-~-
' I I I I
100 1000 10000 100000 1 YEAR 1000000
TIME !minutes)
PUMPING CURVE RN 21481