20100312_21667_Response to PAC Q1.docx Page 1 12 March 2010
Blasting Flyrock and Vibration
Question 1
1. The boundary of ‘Glengarry’ and the southern end of the proposed
east pit are in close
proximity.
a) What does BCC propose to do to ensure that flyrock from mine
blasting does not pose a
hazard to persons, livestock or infrastructure on the adjoining
properties?
b) What does BCC propose to do to ensure that blasting vibration
does not pose rockfall
hazards for persons, livestock or infrastructure on the adjoining
properties?
Response
Whilst the southern end of the proposed east pit is in close
proximity to the boundary of
‘Glengarry’, open hole sub-crop exploration drilling indicates that
from the line of the pit lowwall for
a distance of approximately fifty metres, overburden has been heat
affected and will not require
blasting prior to its excavation.
When blasting operations are carried out the major issues to be
considered in the blast design are:
flyrock
vibration levels
overpressure levels
Prior to the commencement of the Bulk Sample operation BCC
commissioned Scott Mine Consulting
Services P/L to prepare a report on the effect of blasting on water
in-flows into the pit and included
in this report were detailed blast design criteria.
Monitoring of all blasts was undertaken during the Bulk Sample
excavation and records show that
both ground vibration and overpressure were well below allowable
limits and flyrock was contained
within the immediate blast area with every blast.
The blasting was carried out within 200 metres of a neighbour’s
property boundary.
Drill and blast data gathered during the Bulk Sample operation was
used by Scott to update the
blasting report which is included in the WRA and Draft WMP as
Appendix 16.
In the development of blasting procedures for the proposed Bickham
Coal Mine, the priority is the
removal of hazards to persons, livestock and infrastructure. In the
case of people and livestock an
exclusion zone of 500 metres around the blast area is the preferred
method of hazard reduction.
To achieve this with neighbouring properties, protocols of
communication will be developed for
advanced warning and securing control of the exclusion zone during
the blast. Bickham will also
fund the cost of additional fencing of sections of neighbouring
properties if required to isolate stock
from the exclusion zones during blasting operations.
Control of flyrock, vibration levels and overpressure will be
achieved by using the Scott report
guidelines and following blasting practices already developed at
Rixs Creek Mine and Bloomfield
Colliery where mining operations have regularly been carried out in
close proximity to major
infrastructure. The practices will be verified for the conditions
at Bickham by the monitoring of
blasting during the initial years and the alteration to procedures
as required.
The mine site blasting personnel will be supported by the preferred
explosives supplier Orica’s
technical services where required.
20100316_21667_Response to PAC Q2.docx Page 1 16 March 2010
No Flow and Low Flow Days
Question 2
2. The predicted reduced flows in Kingdon Ponds and the Pages River
have the potential to impact
downstream extractive users. The PAC requests that BCC provide an
assessment of the change
to the frequency of no flow days and the frequency of small flows
(less than 5 ML/day) at the
locations of the main downstream users.
Response
The responses to Question 2 for the Pages River and Kingdon Ponds
are presented separately below.
1 Pages River
1.1 Scope
One of the principles established in the draft WMP (Section C2.3)
is for supplementary supplies from
interception bore(s) to replace any reduction of groundwater
baseflow to the Pages River as a result
of mine dewatering during the operational life of the mine. This
discharge would be maintained up
to the completion of post-mining rehabilitation works. Therefore,
there would be no effect on
downstream extractive users on the Pages River during the mine
operation period (years 1 to 27).
The WRA (Section B4.11.2) recognises that different sections of the
Pages River can be classified as
„gaining or „losing. Overall, the Pages River adjacent to the mine
is predicted to receive a net
contribution from baseflow of 650 to 850 kilolitres per day
(kL/day). However, even though there
may be a contribution to baseflow from groundwater in some reaches,
in the absence of surface
runoff contribution, all river systems experience progressive net
loss of water downstream through
natural processes such as infiltration and evaporation.
The report prepared in response to submissions (Section 5.5) quotes
an analysis to quantify
transmission losses in a section of the Upper Hunter River which is
the adjacent catchment to the
Isis River which joins the Pages River upstream of Gundy. The
analysis showed that the average
losses over a 75 km reach were 150 kL/day/km.
The WRA (Appendix 6 Table 3.1) identifies 11 surface water licences
on the Pages River between the
Project and the Isis River confluence. Two of these licences
(20SL045186 and 20SL043226) are in
proximity to the Project and could potentially be affected by any
significant change in the flow in the
Pages River in the post-mining period. The other nine surface water
licences are much further
downstream and the Projects post-mining effect on these sections of
the river during periods of low
flow would be negligible once losses resulting from infiltration
and evaporation over this distance are
taken into account.
In conducting the requested assessment, only the expected reduction
in groundwater baseflow to
the Pages River is considered. Any potential reduction in surface
water runoff from the Project area
to Splitters Creek or directly to the Pages River is not considered
as it is unlikely to affect the low
flow regime.
20100316_21667_Response to PAC Q2.docx Page 2 16 March 2010
1.2 Predicted Baseflow Reduction
The WRA (Section B5.6.1) describes the Projects potential effect on
baseflow in the Pages River.
Total predicted baseflow rates for the Pages River at the Project
area at year 0 are 825 kL/day,
reducing to a minimum of 602 kL/day in year 35, 10 years after the
completion of mining, before
starting to recover. Baseflow contributions are fully restabilised
at about 95% of the pre-mining
level by year 95, 70 years after the completion of mining.
1.3 Baseline Data
The WRA (Appendix 18 Section 4.1) uses the stream gauge operated by
the NSW Office of Water at
Blandford (Station 210061) since 1960 to describe the flow regime
in the Pages River. This gauge
station is located about 5 kilometres upstream of the Project area.
The Blandford gauge has a
catchment area of 303 square kilometres and measures the combined
flow from the Upper Pages
River, Warlands Creek and Scotts Creek catchments as shown in
Appendix 18 Figure 3.1. Splitters
Creek joins the Pages River between the Blandford gauge and the
northern boundary of the Project
area.
Continuous flow records have been collected at the Blandford gauge
since 1983. For the WRA, mean
daily flow data for the period 1960 – 2008 was obtained from the
NSW Water Information website
(http://waterinfo.nsw.gov.au accessed 5 January 2009). The WRA
(Appendix 18 Figure 4.2)
included flow duration curves for both the full period of record
and the period from 2000 to 2008.
The flow data used in the WRA was reviewed in Section 5.2 of the
Projects Submissions Report. For
the purposes of providing a definitive basis to some of the
submissions received, a copy of the
NSW Office of Waters data archive for the Blandford gauge from 1
January 1998 onwards was
combined with data from the Pinneena CD from 21 May 1960 to 31
December 1997. This flow data
(21 May 1960 to 31 December 2009) has been used to assess the
potential effects of predicted
reduced flows on surface water licences 20SL045186 and
20SL043226.
1.4 Method
BCC has undertaken a low flow analysis to assess the potential
impacts to surface water licences
20SL045186 and 20SL043226. The analysis was performed using the
following method:
flow data from the Pinneena CD and the NSW Office of Waters data
archive for the Blandford
gauge for the period 21 May 1960 to 31December 2009 were combined
to establish an
estimate of baseline flow at the Project area. It should be noted
that because this data does
not include flows from Splitters Creek or the baseflow contribution
between the Blandford
gauge and “South Bickham” the analysis will tend to over estimate
the impact of the Project;
the „total baseflow reduction shown in Figure B5.14 of the WRA for
years 27 to 100 (i.e. the
73 years following the end of operation of the mine and the ceasing
of replacement flows)
was divided into approximately 20-year periods (years 27-45, 45-65,
65-85, 85-100) and an
average baseflow reduction calculated for each of these periods.
Years 100 to 125 were
excluded from the analysis as the modelling indicated no total
baseflow reduction in these
years (see Figure B5.14 of the WRA);
for each period, the baseline flow data was modified to include the
predicted average
baseflow reduction for that period;
the data was analysed to identify whether there was an increase in
no flow days (less than
1 ML/day) and small flow days (less than 5 ML/day);
a flow duration curve was plotted for each period showing flow
versus the number of days
per year that the flow was equalled or exceeded;
20100316_21667_Response to PAC Q2.docx Page 3 16 March 2010
this method was repeated for a 7.5% mean annual rainfall reduction
to account for potential
climate change effects. This reduction is consistent with the
climate change scenario
adopted for the Bickham area in Section 4.22 of the Submissions
Report for the year 2070.
An elasticity of 3 has been applied to establish the likely
reduction in runoff (20%) resulting
from the predicted climate change. This elasticity value is
consistent with that adopted in
the WRA (Section 7.4). In order to provide a „worst case
assessment, this reduction in
runoff was applied uniformly across the entire 100-year analysis
period. In practice, climate
change effects can be expected to occur progressively over time and
are likely to have more
effect on the middle and high flow range, rather than low flows
that are sustained by
groundwater baseflow.
1.5 Results
Table 1 compares the number of no flow days (less than 1 ML/day)
and small flow days (less than
5 ML/day) for each 20-year period following the completion of
mining. The greatest effect on
surface water licences 20SL045186 and 20SL043226 would occur in the
years following the
completion of mining (years 25-65) when there would be an average
of approximately one additional
low flow day and four additional small flow days per year. The
predicted climate change scenario
would result in an increase in the number of low and small flow
days relative to the baseline. The
relative increase in low flow days would be slightly worse in years
25-45 than the no climate change
scenario. The relative increase in small flow days would be less
than the no climate change
scenario.
Table 1 No flow and small flow days, years 25-100, Pages
River
Baseline flow Years 25-45 Years 45-65 Years 65-85 Years
85-100
Low flow days
Small flow days
Analysis including potential climate change effects
Low flow days
Small flow days
92 94 92 92 92
The flow duration curves for these results are shown in Appendix
A.
2 Kingdon Ponds
2.1 Scope
The WRA (Appendix 6 Table 3.2) included information on 12 surface
water licences on the Kingdon
Ponds between the Project area and Parkville. These licences are
clustered around Wingen and are
predominantly small allocations for domestic purposes. The licences
are the closest licences
downstream of the Project and could potentially be affected by
reduced flow in the Kingdon Ponds
resulting from the Project.
20100316_21667_Response to PAC Q2.docx Page 4 16 March 2010
2.2 Predicted Baseflow Reduction
The WRA (Section B4.11.7) recognises that baseflow contribution to
the upper reaches of the
Kingdon Ponds catchment is small as the streams are
ephemeral.
The WRA (Section B5.6.2) describes the Projects potential effect on
baseflow in the Kingdon Ponds.
Total predicted baseflow rates for the Kingdon Ponds at the Project
area at year 0 are 41 kL/day,
reducing to a minimum of 26 kL/day in year 40, 15 years after
completion of mining, before starting
to recover. Baseflow restabilises at around 83% of the pre-mining
baseflows in year 105, 80 years
after the completion of mining.
2.3 Baseline data
The WRA (Appendix 18 Section 4.2) uses the stream gauge operated by
the NSW Office of Water at
Parkville (Station 210093) to describe the flow regime in the Pages
River. This gauge station is
located about 19 kilometres downstream of the Project area. The
Parkville gauge has a catchment
area of 177 square kilometres. Flow measurement began at Parkville
in 1972, but the record has
over four years of missing data, mainly in the period 1989 to 1993.
The WRA obtained mean daily
flow data for the period 1972 – 2008 from the NSW Water Information
website
(http://waterinfo.nsw.gov.au accessed 5 January 2009). The WRA
(Appendix 18 Figure 4.3)
included a flow duration curve for the period of record. For the
analysis reported below an updated
flow record up to mid December 2009 was obtained from the NSW
Office of Water.
This flow data has been used to assess the potential effects of
predicted reduced flows on the
12 surface water licences on the Kingdon Ponds that are the closest
licences downstream of the
Project area.
2.4 Method
BCC has completed a low flow analysis to assess the potential
impacts to the 12 surface water
licences on the Kingdon Ponds that are the closest licences
downstream of the Project area. The
analysis was performed using the following method:
flow data from the Parkville gauge for the period 1972 - 2009 was
used to estimate baseline
flow at the Project area;
the „total baseflow reduction shown in Figure B5.15 of the WRA for
years 0 to 125 was
divided into approximately 20-year periods (years 0-25, 25-45,
45-65, 65-85, 85-105, 105-
125) and an average baseflow reduction calculated for each of these
periods;
for each period, the baseline flow data was modified to include the
predicted average
baseflow reduction for that period;
the data was analysed to identify whether there was an increase in
no flow days (less than 1
ML/day) and small flow days (less than 5 ML/day);
a flow duration curve was plotted for each period showing flow
versus the number of days
per year that the flow was equalled or exceeded;
this method was repeated for a 7.5% mean annual rainfall reduction
to account for potential
climate change effects. This reduction is consistent with the
climate change scenario
adopted for the Bickham area in Section 4.22 of the Submissions
Report for the year 2070.
An elasticity of 3 has been applied to establish the likely
reduction in runoff (20%) resulting
from the predicted climate change. This elasticity value is
consistent with that adopted in
the WRA (Section 7.4). In order to provide a „worst case
assessment, this reduction in
runoff was applied uniformly across the entire 100-year analysis
period. In practice, climate
change effects can be expected to occur progressively over time and
are likely to have more
20100316_21667_Response to PAC Q2.docx Page 5 16 March 2010
effect on the middle and high flow range, rather than low flows
that are sustained by
groundwater baseflow.
2.5 Results
Table 2 compares the number of no flow days (less than 1 ML/day)
and small flow days (less than
5 ML/day) for each period of the analysis. The expected reduction
in baseflow would result in an
average of one additional low flow day each year following the
commencement of mining that effects
baseflow to Kingdon Ponds. This is a minor increase from the
current average 63 low flow days per
year. The expected reduction in baseflow would not result in any
change to the average number of
small flow days per year in Kingdon Ponds. The results for the
climate change scenario indicate
there would be no change in the number of low and small flow
days.
Table 2 No flow and small flow days, years 0-125, Kingdon
Ponds
Baseline
flow
Years
0-25
Years
25-45
Years
45-65
Years
65-85
Years
85-105
Years
105-125
Small flow days
Analysis including potential climate change effects
Low flow days
Small flow days
209 209 209 209 209 209 209
The flow duration curves for these results are shown in Appendix
B.
Bickham Coal Project
Appendix A Pages River
0.010
0.100
1.000
10.000
100.000
1000.000
10000.000
100000.000
050100150200250300350
No. of Days Flow Equalled or Exceeded (days per year)
Pages River Flow Duration - Baseline
Baseline Flow (ML/day)
No. of Days Flow Equalled or Exceeded (days per year)
Pages River Flow Duration - Baseline and Years 25 - 100
Baseline Flow (ML/day) Flow, Years 25-45 (ML/day)
Flow, Years 45-65 (ML/day)
Flow, Years 65-85 (ML/day)
Flow, Years 85-100 (ML/day)
Bickham Coal Project Response to PAC, Question 2
0.010
0.100
1.000
10.000
010203040506070
No. of Days Flow Equalled or Exceeded (days per year)
Pages River Flow Duration - Low flow and small flow day close up
Baseline Flow (ML/day) Flow,
Years 25-45 (ML/day)
Bickam Coal Project Response to PAC, Question 2
Flow duration curves including 7.5% rainfall reduction due to
climate change
0.010
0.100
1.000
10.000
100.000
1000.000
10000.000
100000.000
050100150200250300350
No. of Days Flow Equalled or Exceeded (days per year)
Pages River Flow Duration - Baseline
Baseline Flow (ML/day)
No. of Days Flow Equalled or Exceeded (days per year)
Pages River Flow Duration - Baseline and Years 25 - 100
Baseline Flow (ML/day) Flow, Years 25-45 (ML/day)
Flow, Years 45-65 (ML/day)
Flow, Years 65-85 (ML/day)
Flow, Years 85-100 (ML/day)
Bickham Coal Project Response to PAC, Question 2
0.010
0.100
1.000
10.000
010203040506070
No. of Days Flow Equalled or Exceeded (days per year)
Pages River Flow Duration - Low flow and small flow day close up
Baseline Flow (ML/day) Flow,
Years 25-45 (ML/day)
Bickham Coal Project
Appendix B Kingdon Ponds
0.001
0.010
0.100
1.000
10.000
100.000
1000.000
10000.000
100000.000
050100150200250300350
No. of Days Flow Equalled or Exceeded (days per year)
Kingdon Ponds Flow Duration - Baseline
Baseline Flow (ML/day)
No. of Days Flow Equalled or Exceeded (days per year)
Kingdon Ponds Flow Duration - Baseline and Years 0 - 125
Baseline Flow (ML/day) Flow, Years 0-25 (ML/day)
Flow, Years 25-45 (ML/day)
Flow, Years 65-85 (ML/day)
Flow, Years 45-65 (ML/day)
Flow, Years 85-105 (ML/day)
Flow, Years 105-125 (ML/day)
Bickham Coul Project Response to PAC, Question 2
0.010
0.100
1.000
10.000
30405060708090100110120
No. of Days Flow Equalled or Exceeded (days per year)
Kingdon Ponds Flow Duration - Low flow and small flow day close
up
Baseline Flow (ML/day) Flow, Years 0-25 (ML/day)
Flow, Years 25-45 (ML/day)
Flow, Years 65-85 (ML/day)
Flow, Years 45-65 (ML/day)
Flow, Years 85-105 (ML/day)
Flow, Years 105-125 (ML/day)
Bickham Coul Project Response to PAC, Question 2
Flow duration curves including 7.5% rainfall reduction due to
climate change
0.001
0.010
0.100
1.000
10.000
100.000
1000.000
10000.000
100000.000
050100150200250300350
No. of Days Flow Equalled or Exceeded (days per year)
Kingdon Ponds Flow Duration - Baseline
Baseline Flow (ML/day)
No. of Days Flow Equalled or Exceeded (days per year)
Kingdon Ponds Flow Duration - Baseline and Years 0 - 125
Baseline Flow (ML/day) Flow, Years 0-25 (ML/day)
Flow, Years 25-45 (ML/day)
Flow, Years 65-85 (ML/day)
Flow, Years 45-65 (ML/day)
Flow, Years 85-105 (ML/day)
Flow, Years 105-125 (ML/day)
Bickham Coul Project Response to PAC, Question 2
0.010
0.100
1.000
10.000
30405060708090100110120
No. of Days Flow Equalled or Exceeded (days per year)
Kingdon Ponds Flow Duration - Low flow and small flow day close
up
Baseline Flow (ML/day) Flow, Years 0-25 (ML/day)
Flow, Years 25-45 (ML/day)
Flow, Years 65-85 (ML/day)
Flow, Years 45-65 (ML/day)
Flow, Years 85-105 (ML/day)
Flow, Years 105-125 (ML/day)
Bickham Coal Project
20100316_21667_Response to PAC_Q3.docx Page 1 16 March 2010
Uncertainty in Streamflow Measurements
Question 3
3. The PAC notes that gauging surveys have been used to derive
estimates of groundwater
contributions to the Pages River from the proposed mine site. These
estimates have been used
as a verification of the groundwater model predictions of
groundwater fed contributions to the
Pages River. What quantitative accuracy does BCC ascribe to the
gauging results and
subsequent estimates of flow contribution given the difficulties of
measuring flows at the
selected sites and the possibility of diurnal fluctuations
affecting the low flow measurements
during the period that the flow measurements were made?
Response
The WRA (Section B4.9) described streamflow monitoring undertaken
for the Project. The purpose
of the monitoring was to use the collected data to benchmark the
groundwater inflows to the
section of the Pages River within the Project area. Use of the
monitoring data for this purpose is
possible as there are no significant tributaries entering this
section of the Pages River.
Five sites (SF1 to SF5) were selected for periodic measurement of
streamflow:
SF1 – downstream of the pool at the upstream boundary fence
SF2 – just upstream of drainage line on southern edge of the
floodplain
SF3 - just downstream of the abandoned underground mine on the
river bank, upstream of
the long pool
SF4 – 25 metres downstream of the long pool
SF5 – approximately 100 metres upstream of the windmill, near the
southern boundary.
The WRA (Figure B4.17) showed the locations of the streamflow
measurement sites. A copy of this
figure is reproduced in Appendix A.
The river flows across rock outcrop at SF2, SF3 and SF5. Streamflow
can be accurately measured
at these sites because it is all aboveground.
Site SF1 near the northern boundary of “South Bickham” is located
on a riffle zone where shallow
flow occurs across an uneven gravel bed and accurate measurement of
the flow area is difficult. In
addition, the relatively shallow flow does not allow multiple
velocity measurements at different
depths. Site SF4 is located just downstream of the long pool where
the channel is defined by
boulders and there is significant opportunity for flow to occur
along pathways other than the main
visible flow. Not withstanding the limitations of sites SF1 and
SF4, gaugings were undertaken in
anticipation that indicative data could be obtained.
Streamflow measurements were made on four dates:
16 August 2006
20 September 2006
22 January 2007
26 July 2007.
Monitoring data collected at each of the streamflow measurement
sites on these dates is presented
in Table B4-5 of the WRA and reproduced Table 1. Streamflow
recorded at the NSW Office of
Bickham Coal Project
20100316_21667_Response to PAC_Q3.docx Page 2 16 March 2010
Water’s Blandford gauge on and immediately prior to the monitoring
dates is also included in Table
B4-5 for comparison purposes. The approximate total groundwater
inflows to the section of the
Pages River within the Project area was estimated by calculating
the increase in streamflow rate
between streamflow measurement sites SF2 and SF5. These sites were
selected for this calculation
as they are the furthest apart sites at which the streamflow can be
measured with a high degree of
accuracy as described above. This calculation showed a reasonably
consistent increase in
streamflow between these two sites in the range of 650-850 kL/d
(8-10 L/s). (The very low flow
measurements on 22 January 2007 were almost certainly adversely
affected by high rates of
evaporation relative to total flow rate.)
Records of the streamflow measurements including photos of the
measurement sites and the
gauging procedure are provided in Appendices B to E.
Section 2 considers the accuracy of the streamflow measurements and
any subsequent effect on
the estimated groundwater inflows to the section of the Pages River
within the Project area.
2 Streamflow Measurement Method
Australian Standard 3778 “Measurement of Water Flow in Open
Channels” provides comprehensive
guidance on streamflow measurement including the selection of
measurement methods and
estimation of uncertainty.
The streamflow measurements undertaken for the Project used the
velocity-area by wading
method which is included in the standard. This method is recognised
as suitable for measuring
streamflow in narrow width, shallow depth and low velocity streams.
The standard recommends
that this method be used at measurement sites that have no
cross-currents, are relatively free
from vegetation, and are fairly straight and uniform in
cross-section. The selected measurement
sites generally complied with these recommendations in that the
flow was well defined, as opposed
to dispersed low velocity flow in a pool.
A stationary rotating-element current meter was used to measure
flow. In accordance with the
standard, the cross-section of the open channel at each of the
measurement sites was divided into
several segments. A sufficient number of segments were defined to
enable the shape of the bed to
be defined at each site. The width of each segment and the depth of
the mean velocity at a
vertical in each segment were measured. The total discharge through
the cross-section was
calculated by summing the products of velocity, width and depth of
each segment.
The one-point method was used to measure the flow velocity in most
of the segments. In
accordance with the standard for this method, velocity observations
were made on each vertical by
exposing the current meter at 0.6 of the depth below the surface.
In some deeper segments,
velocity was observed at either two points (0.2 and 0.8 of the
depth below surface) or three points
(0.2, 0.6 and 0.8 of the depth below surface).
The velocity at each point was observed by exposing the
rotating-element current meter for a
minimum of 30 seconds, in accordance with the standard. The value
observed was taken as the
mean velocity in the vertical. Replicate measurements were made to
check for consistency. The
velocities at the banks of each site were taken to be zero. The
velocity for each site was then
calculated using the arithmetic method, which involves summing the
discharge from each of the
individual segments.
20100316_21667_Response to PAC_Q3.docx Page 3 16 March 2010
3 Accuracy of the Streamflow Measurements
AS3778 identifies the minimum uncertainty of streamflow
measurements taken using the velocity-
area method by wading as being up to 5% where the velocity is
observed at 0.6 times the depth.
The error margin has been calculated for each of the measurements
sites on each measurement
date in accordance with AS3778.3.1-2001 Annex E Uncertainty of a
Velocity-area Measurement.
The critical factors that affect the uncertainty are:
number of verticals;
observation time; and
velocity.
The measurements taken on 22 January 2007 and 26 July 2007 were
undertaken by Ecowise
Environmental. Ecowise has calculated that the measurements taken
on these dates have an error
margin of approximately 10-15% and 5-6% respectively. The higher
error margins on 22 January
2007 reflects the very low flow on this date and the resultant use
of one point flow measurements
of very shallow flows only and the division of the stream into a
smaller number of segments.
The flow measurements taken on 16 August 2006 and 20 September 2006
were taken by Evans &
Peck using the same technique to that followed by Ecowise. These
measurements were not taken
on days when the flow at the Blandford gauge was low (in the 83rd –
96th percentile flow range) but
not as low as on 22 January 2007 (zero flow at the Blandford
gauge). The error margin on these
measurements is therefore expected to be similar to the 5-6% error
margin calculated by Ecowise
for the measurements they took on 26 July 2007.
4 Effects on Flow Contribution Estimates
The effect of the uncertainty in the streamflow measurements on the
estimate of groundwater
inflow to the Pages River in the Project areas has been calculated
by applying the error margin to
each streamflow measurement and then recalculating the change in
streamflow between
measurement sites SF2 and SF5 consistent with the method followed
in the WRA (Section B4.9).
As the error margins are similar for SF2 and SF3 on all dates used
to estimate the contribution of
groundwater to streamflow (i.e. all dates except 22 January 2007),
the total error margin of the
estimate would be similar i.e. approximately 5-6%, particularly as
any error in the measurements
is likely to be common to all the measurements taken on that
day.
5 Diurnal Streamflow Fluctuations
BCC has obtained continuous streamflow data from the NSW Office of
Water’s Blandford gauge for
the days on which streamflow measurements were taken and also the
preceding day. The
continuous streamflow data comprises an hourly record of the stream
height. Plots of the data
have been created and are provided in Appendix F. A visual
inspection of these plots shows that
no diurnal effect is evident in the streamflow measurements taken
at the Blandford gauge on
16 August 2006, 20 September 2006 and 25 July 2007. There is
potentially a diurnal effect on the
streamflow data for 22 January 2007. This is consistent with the
observation in the WRA
(Section B4.9) that the very low flow measurements on 22 January
2007 were almost certainly
affected by high rates of evaporation relative to total flow rate.
The flow measurements on
22 January 2007 were not considered in the estimation of the
groundwater inflow between
streamflow measurement sites SF2 and SF5.
Bickham Coal Project
20100316_21667_Response to PAC_Q3.docx Page 4 16 March 2010
Table 1 - Measured Streamflows in Pages River
Streamflow measurement site 16 Aug 2006 20 Sep2006 22 Jan 2007 26
July 2007
L/s kL/d L/s kL/d L/s kL/d L/s kL/d
NSW Office of Water’s Blandford monitoring gauge
Day before streamflow measurements 24 2,070 53 4,580 0 0 213
18,400
Day of streamflow measurements 23 1,980 58 5,010 0 0 206
17,800
Bickham Project Area
SF1 downstream of the pool at the upstream boundary fence * * 17
1,465 0 0 138 11,900
SF2 just upstream of drainage line on southern edge of the
floodplain
SF3 just downstream of the abandoned underground mine the on
river bank, upstream of the long pool
28 2,410 16 1,380 2.6 220 111 9,570
SF4 25 metres downstream of the long pool * * 18 1,550 2.1 180 123
10,600
SF5 Approximately 100 metres upstream of the windmill, near
the
southern boundary
flow
approx
-240
approx
Bickham Coal Project
20100316_21667_Response to PAC_Q3.docx Page 5 16 March 2010
Table 2 – Uncertainty in streamflow measurements
Flow
(kL/day)
Uncertainty
SF4 - - - -
20 September 2006
22 January 2007
SF5 <50 - <50 <50
Appendix A Figure B4.17 from the WRA
Appendix B Streamflow Monitoring Records
16 August 2006
Summary
Location Section Flow Flow (m3/s) (L/s)
Just upstream of drainage line on southern edge of the floodplain 1
0.021 21 Just downstream of abandoned underground mine on river
bank 2 0.028 28 Approx 100 m upstream of windmill near southern
boundary 3 0.031 31
Site 1 Just upstream of drainage line on southern edge of the
floodplain
Section width (mm) 1,200 + 200 Section F A B C D E H Total Distance
Across (mm) 120 200 400 600 800 1000 Section Width (mm) 160 140 200
200 200 300 200 1,400 Depth at Section (mm) 60 120 210 350 360 240
60 Section Area (m2) 0.0048 0.0168 0.042 0.07 0.072 0.045 0.0078
Depth for Reading 1 (bottom) 60 120 210 320 340 240 9.22 Average
Reading 1 4.58 9.74 7.47 8.04 5.97 6.38 Depth for Reading 2
(middle) 150 190 200 150 Average Reading 2 9.46 10.97 6.37 5.66
Depth for Reading 3 (top) 60 60 60 60 60 Average Reading 3 9.95
11.65 9.73 9.36 6.1 Average Velocity for Section (m/s) 0.0458
0.09845 0.095267 0.0958 0.072333 0.060467 0.0922 Section Discharge
(m3/s) 0.0002 0.0017 0.0040 0.0067 0.0052 0.0027 0.0007 Total
Discharge 0.021
Notes Section H: Separate trickle discharge on right of gauging
site Check on surface flow velocity (time (s) over 1 m) 13, 9, 9,
10, 9 = Average 10s = 0.1 m/s
Bickham Streamgauging 16 August 2006 Site 2a Left hand flow path
just downstream of abandoned underground mine on river bank
Section width (mm) 750 Section A B C D E F G H Total Distance
Across (mm) 50 150 250 500 Section Width (mm) 100 100 175 375 750
Depth at Section (mm) 90 140 150 60 Section Area (m2) 0.009 0.014
0.02625 0.019688 Depth for Reading 1 (bottom) 70 140 150 60 Average
Reading 1 18.37 13.69 15.87 15.75 Depth for Reading 2 (middle) 100
100 190 Average Reading 2 22.86 20.41 10.97 Depth for Reading 3
(top) 60 60 60 Average Reading 3 23.66 21.51 9.73 Average Velocity
for Section (m/s) 0.1837 0.2007 0.192633 0.1575 Section Discharge
(m3/s) 0.0017 0.0028 0.0051 0.0031 Total Discharge 0.0126
Notes Check on surface flow velocity (time (s) over 3 m) 14, 15, 15
= Average 14.6s = 0.2 m/s
Site 2b Right hand flow path just downstream of abandoned
underground mine on river bank
Section width (mm) 650 Section A B C D E F G H Total Distance
Across (mm) 50 100 300 500 600 Section Width (mm) 75 125 200 150
100 650 Depth at Section (mm) 110 120 85 120 90 Section Area (m2)
0.00825 0.015 0.017 0.018 0.0045 Depth for Reading 1 (bottom) 110
120 120 Average Reading 1 23.6 32.22 25 Depth for Reading 2
(middle) Average Reading 2 Depth for Reading 3 (top) 60 60 85 60 80
Average Reading 3 30.72 29.18 18 28.18 13.6 Average Velocity for
Section (m/s) 0.2716 0.307 0.18 0.2659 0.136 Section Discharge
(m3/s) 0.0022 0.0046 0.0031 0.0048 0.0006 Total Discharge
0.0153
Total Section Discharge 0.028
Bickham Streamgauging 16 August 2006
Site 3 Approx 100 m upstream of windmill near southern
boundary
Section width (mm) 1,580 Section A B C D E F G H Total Distance
Across (mm) 100 300 500 700 950 1500 Section Width (mm) 200 200 200
200 250 230 300 1,580 Depth at Section (mm) 60 70 110 105 205 115
Section Area (m2) 0.008 0.014 0.022 0.022 0.049 0.013 0.0065 Depth
for Reading 1 (bottom) 60 60 110 105 205 80 Average Reading 1 15.21
19.65 18.47 18.34 20.78 60.6 Depth for Reading 2 (middle) 130
Average Reading 2 27.07 Depth for Reading 3 (top) 60 60 60 Average
Reading 3 18.53 16.96 28.49 Average Velocity for Section (m/s)
0.1521 0.1965 0.185 0.1765 0.254467 0.606 0.05 Section Discharge
(m3/s) 0.0012 0.0028 0.0041 0.0039 0.010244 0.0080 0.0003 Total
Discharge 0.0305
Notes Section H = shallow section between 1050 and 1350. Velocity
is estimate only
Site 3 Section Detail Distance Depth (mm) (mm)
0 0 100 -60 300 -70 500 -110 700 -105 750 -125 800 -140 850 -170
900 -195 950 -195
1000 -125 1050 -60 1100 -20 1150 -25 1200 -15 1250 0 1300 -10 1350
-20 1400 -50 1450 -90 1500 -115 1550 -30 1580 0
-250
-200
-150
-100
-50
0
D ep
th (m
Bickham Streamgauging 16 August 2006
Site 1 Just upstream of drainage line on southern edge of the
floodplain
Site 2 Just downstream of abandoned underground mine on river
bank
11/03/2010
Site 3 Approx 100 m upstream of windmill near southern
boundary
11/03/2010
20 September 2006
Bickham Streamflow Gauging Site 1
Bickham Streamflow Gauging Site 2
Bickham Streamflow Gauging Site 3
Bickham Streamflow Gauging Site 4
Bickham Streamflow Gauging Site 5
Appendix D Streamflow Monitoring Records
22 January 2007
ECOWISE Environmental Station: SITE 1 A Gauging No: 1.0 Date:
22/01/2007 16:05 VarFrom: 100 - Stream Water Level (metres) VarTo:
141 - Stream Discharge (megalitres per day) Meter: 05-22 0522521
Fan: 05-21 Method: WA - Wading Quality: 150 - Rating table
extrapolated due to inadequate gauging information Party: Adam
& Melissa Comments Gauge Readings Logger Gauge Time Start (m)
0.000 0.000 16:05 End (m) 0.000 0.000 16:10 Mean (m) 0.000 0.000
Results Name Value Units Quality Discharge 0.139 Ml/day 150 Area
0.757 % 150 Velocity 0.212 m/s 150 Maximum Depth 0.000 ? 150
Maximum Velocity 0.000 ? 150 Slope 0.000 mm 150 Mannings N 0.000
min 150 Wetted Perimeter 0.236 m 150 Width 0.180 m 150 Num Sections
7.000 150 Temperature 0.000 øC 150 Sigma AD 0.002 150 Hydraulic
Radius 0.000 ? 150 Total Error 0.147 150 Turbidity 0.000 NTU 150
Rating (not found) Shift (m): 0.00 Without Shift With Shift
Discharge (Ml/day) 0.000 0.000 % Deviation 0.00 0.00 Di stance
Vert. Depth Type % Estimate Obs. Depth Obs. Time Revolutions Obs.
Velocity Vert. Velocity Sect. Vel Sect. Sect. Flow % Flow Comment
0.92 0.00 Left Bank 66.0 0.00 0.153 0.001 0.000 0.083 Section A
0.89 0.05 One Point 100.0 0.03 40.00 146 0.232 0.232 0.232 0.002
0.000 0.270 0.86 0.06 One Point 100.0 0.04 40.00 145 0.231 0.231
0.230 0.002 0.000 0.268 0.83 0.05 One Point 100.0 0.03 40.00 143
0.228 0.228 0.221 0.002 0.000 0.303 0.79 0.05 One Point 100.0 0.03
40.00 133 0.215 0.215 0.211 0.001 0.000 0.194 0.76 0.04 One Point
100.0 0.03 40.00 127 0.206 0.206 0.136 0.000 0.000 0.039 0.74 0.00
Right Bank 66.0 0.00
0.884 0.848 0.812 0.776 distance (m)
0.08
0.06
0.04
0.02
1
2
WELB WERB
ECOWISE Environmental Station: SITE 1B Gauging No: 1.0 Date:
22/02/2007 16:11 VarFrom: 100 - Stream Water Level (metres) VarTo:
141 - Stream Discharge (megalitres per day) Meter: 05-22 0522521
Fan: 05-21 Method: WA - Wading Quality: 150 - Rating table
extrapolated due to inadequate gauging information Party: AM/MR
Comments Not ideal section Gauge Readings Logger Gauge Time Start
(m) 0.000 0.000 16:11 End (m) 0.000 0.000 16:16 Mean (m) 0.000
0.000 Results Name Value Units Quality Discharge 0.158 Ml/day 1
Area 1.500 % 1 Velocity 0.122 m/s 1 Maximum Depth 0.000 ? 1 Maximum
Velocity 0.000 ? 1 Slope 0.000 mm 1 Mannings N 0.000 min 1 Wetted
Perimeter 0.443 m 1 Width 0.400 m 1 Num Sections 9.000 1
Temperature 0.000 øC 1 Sigma AD 0.003 1 Hydraulic Radius 0.000 ? 1
Total Error 0.124 1 Turbidity 0.000 NTU 1 Rating (not found) Shift
(m): 0.00 Without Shift With Shift Discharge (Ml/day) 0.000 0.000 %
Deviation 0.00 0.00 Di stance Vert. Type % Estimate Obs. Depth Obs.
Time Revolutions Obs. V Vert. Velocity Sect. Vel Sect. Sect. Flow %
Flow Comment 1.00 0.00 Right Bank 66.0 0.00 0.077 0.001 0.000 0.055
0.95 0.05 One Point 100.0 0.03 40.00 61 0.117 0.117 0.122 0.002
0.000 0.194 0.90 0.06 One Point 100.0 0.03 40.00 69 0.128 0.128
0.137 0.003 0.000 0.238 0.85 0.06 One Point 100.0 0.03 40.00 82
0.146 0.146 0.143 0.002 0.000 0.216 0.80 0.04 One Point 100.0 0.02
40.00 79 0.141 0.141 0.145 0.002 0.000 0.206 0.75 0.05 One Point
100.0 0.03 40.00 84 0.148 0.148 0.098 0.004 0.000 0.248 0.70 0.02
Sounding 100.0 0.00 40.00 0 Depth only
0.65 0.04 Sounding 100.0 0.00 40.00 0 Depth only 0.60 0.00 Left
Bank 66.0 0.00
0.6 0.7 0.8 0.9 1 distance (m)
0.08
0.06
0.04
0.02
WELB WERB
ECOWISE Environmental Station: D/S Abandoned under ground mine
“RIVERBANK” Gauging No: 1.0 Date: 22/02/2007 14:05 VarFrom: 100 -
Stream Water Level (metres) VarTo: 141 - Stream Discharge
(megalitres per day) Meter: 05-22 0522521 Fan: 05-21 Method: WA -
Wading Quality: 10 - Good reliable gauging Party: AM/MR Comments
Just downstream of abandoned underground mine Gauge Readings Logger
Gauge Time Start (m) 0.000 0.000 14:05 End (m) 0.000 0.000 14:25
Mean (m) 0.000 0.000 Results Name Value Units Quality Discharge
0.226 Ml/day 1 Area 6.295 % 1 Velocity 0.042 m/s 1 Maximum Depth
0.000 ? 1 Maximum Velocity 0.000 ? 1 Slope 0.000 mm 1 Mannings N
0.000 min 1 Wetted Perimeter 0.732 m 1 Width 0.480 m 1 Num Sections
13.000 1 Temperature 0.000 øC 1 Sigma AD 0.024 1 Hydraulic Radius
0.000 ? 1 Total Error 0.092 1 Turbidity 0.000 NTU 1 Rating (not
found) Shift (m): 0.00 Without Shift With Shift Discharge (Ml/day)
0.000 0.000 % Deviation 0.00 0.00 Distance Vert. Type % Estimate
Obs. Depth Obs. Time Revolutions Obs. V Vert. Velocity Sect. Vel
Sect. Sect. Flow % Flow Comment 0.20 0.00 Left Bank 66.0 0.00 0.000
0.004 0.000 0.000 0.25 0.17 One Point 100.0 0.00 40.00 0 0.000
0.000 0.019 0.008 0.000 0.068 0.30 0.16 One Point 100.0 0.10 40.00
10 0.037 0.037 0.040 0.008 0.000 0.137 0.35 0.15 One Point 100.0
0.09 40.00 14 0.043 0.043 0.043 0.008 0.000 0.148 0.40 0.17 One
Point 100.0 0.10 40.00 13 0.042 0.042 0.043 0.008 0.000 0.147 0.45
0.14 One Point 100.0 0.08 40.00 15 0.045 0.045 0.051 0.008 0.000
0.168 0.50 0.16 One Point 100.0 0.10 40.00 22 0.056 0.056 0.057
0.005 0.000 0.116 0.53 0.15 One Point 100.0 0.09 40.00 23 0.058
0.058 0.060 0.004 0.000 0.114 0.56 0.14 One Point 100.0 0.08 40.00
26 0.063 0.063 0.062 0.004 0.000 0.117 0.59 0.15 One Point 100.0
0.09 40.00 25 0.061 0.061 0.060 0.004 0.000 0.114 0.62 0.14 One
Point 100.0 0.08 40.00 24 0.059 0.059 0.030 0.002 0.000 0.030 0.65
0.01 One Point 100.0 0.00 40.00 0 0.000 0.000 0.000 0.000 0.000
0.000 Depth only 0.68 0.00 Right Bank 66.0 0.00
0.2 0.296 0.392 0.488 0.584 0.68 distance (m)
0.16
0.12
0.08
0.04
WELB WERB
ECOWISE Environmental Station: D/S BIG POOL Gauging No: 1.0 Date:
22/02/2007 11:00 VarFrom: 100 - Stream Water Level (metres) VarTo:
141 - Stream Discharge (megalitres per day) Meter: 05-22 0522521
Fan: 05-21 Method: WA - Wading Quality: 10 - Good reliable gauging
Party: AM/MR Comments Approximately 45m d/s of "Big Pool" Gauge
Readings Logger Gauge Time Start (m) 0.000 0.000 11:00 End (m)
0.000 0.000 11:20 Mean (m) 0.000 0.000 Results Name Value Units
Quality Discharge 0.184 Ml/day 1 Area 2.850 % 1 Velocity 0.075 m/s
1 Maximum Depth 0.000 ? 1 Maximum Velocity 0.000 ? 1 Slope 0.000 mm
1 Mannings N 0.000 min 1 Wetted Perimeter 0.550 m 1 Width 0.410 m 1
Num Sections 10.000 1 Temperature 0.000 øC 1 Sigma AD 0.008 1
Hydraulic Radius 0.000 ? 1 Total Error 0.115 1 Turbidity 0.000 NTU
1 Rating (not found) Shift (m): 0.00 Without Shift With Shift
Discharge (Ml/day) 0.000 0.000 % Deviation 0.00 0.00 Distance Vert.
Type % Estimate Obs. Depth Obs. Time Revolutions Obs. V Vert.
Velocity Sect. Vel Sect. Sect. Flow % Flow Comment 1.03 0.00 Left
Bank 66.0 0.00 0.023 0.001 0.000 0.016 1.08 0.05 One Point 100.0
0.03 40.00 9 0.035 0.035 0.164 0.003 0.001 0.312 1.13 0.09 One
Point 100.0 0.05 4.00 19 0.292 0.292 0.172 0.004 0.001 0.411 1.18
0.09 One Point 100.0 0.05 40.00 20 0.053 0.053 0.052 0.003 0.000
0.089 1.23 0.04 One Point 100.0 0.03 40.00 19 0.051 0.051 0.047
0.003 0.000 0.082 1.28 0.09 One Point 100.0 0.05 40.00 13 0.042
0.042 0.044 0.005 0.000 0.108 1.33 0.09 One Point 100.0 0.05 40.00
16 0.047 0.047 0.036 0.004 0.000 0.084 1.38 0.08 One Point 100.0
0.05 40.00 3 0.026 0.026 0.025 0.004 0.000 0.053 1.43 0.08 One
Point 100.0 0.05 40.00 2 0.024 0.024 0.016 0.000 0.000 0.003 1.44
0.00 Right Bank 66.0 0.00
1.03 1.112 1.194 1.276 1.358 1.44 distance (m)
0.08
0.06
0.04
0.02
1
26 July 2007
ECOWISE Environmental
Details (not found) Station: BICKHAM SITE 1 Gauging No: 1.0 Date:
26/07/2007 00:00 VarFrom: 100 - Stream Water Level (metres) VarTo:
141 - Stream Discharge (megalitres per day) Meter: 85-29 85291 Fan:
1 Method: WA - Wading Quality: 150 - Data not yet quality coded -
Hydsys default Party:
Comments
Gauge Readings Logger Gauge Time Start (m) 0.000 0.000 00:00 End
(m) 0.000 0.000 00:00 Mean (m) 0.000 0.000
Results Name Value Units Quality Discharge 11.979 Ml/day 150 Area
0.634 m2 150 Velocity 0.219 m/s 150 Maximum Depth 0.330 m 150
Maximum Velocity 0.419 m/s 150 Slope 0.000 m 150 Mannings N 0.000
l/s 150 Wetted Perimeter 3.688 m 150 Width 0.000 ? 150 Num Sections
0.000 ? 150 Temperature 0.000 øC 150 Sigma AD 0.000 ? 150 Hydraulic
Radius 0.172 m 150 Total Error 0.000 ? 150 Turbidity 0.000 NTU
150
Rating (not found) Shift (m): 0.00 Without Shift With Shift
Discharge (Ml/day) 0.000 0.000 % Deviation 0.00 0.00
Distance Vert. Type % Estimate Obs. Depth Obs. Time Revolutions
Obs. V Vert. Velocity Sect. Vel Sect. Sect. Flow % Flow Comment
4.80 0.00 Left Bank 0.000 0.020 0.000 0.000 4.40 0.10 One Point
50.0 0.06 40.00 17 0.046 0.046 0.108 0.032 0.003 0.028 4.10 0.11
One Point 100.0 0.07 40.00 101 0.170 0.170 0.165 0.040 0.007 0.056
3.80 0.16 One Point 100.0 0.10 40.00 93 0.159 0.159 0.184 0.033
0.006 0.051 3.60 0.17 One Point 100.0 0.10 40.00 128 0.209 0.209
0.240 0.035 0.008 0.070 3.40 0.18 One Point 100.0 0.11 40.00 172
0.271 0.271 0.257 0.039 0.010 0.084 3.20 0.21 One Point 100.0 0.13
40.00 152 0.243 0.243 0.286 0.044 0.013 0.105 3.00 0.23 One Point
100.0 0.14 40.00 213 0.330 0.330 0.319 0.039 0.012 0.104 2.85 0.29
Three Point 100.0 0.06 40.00 125 0.205 0.309 0.322 0.044 0.014
0.119 0.17 40.00 194 0.303 0.23 40.00 276 0.419 2.70 0.30 Two Point
100.0 0.06 40.00 159 0.253 0.335 0.324 0.047 0.015 0.128 0.24 40.00
275 0.418 2.55 0.33 Two Point 100.0 0.07 40.00 152 0.243 0.313
0.280 0.049 0.014 0.114 0.26 40.00 250 0.382 2.40 0.32 Three Point
100.0 0.06 40.00 72 0.129 0.247 0.237 0.047 0.011 0.093 0.19 40.00
138 0.223 0.26 40.00 254 0.388 2.25 0.31 Three Point 100.0 0.06
40.00 103 0.173 0.227 0.224 0.042 0.009 0.078 0.19 40.00 83 0.145
0.25 40.00 236 0.363 2.10 0.25 One Point 100.0 0.15 40.00 136 0.220
0.220 0.194 0.043 0.008 0.070 1.90 0.18 One Point 100.0 0.11 40.00
99 0.168 0.168 0.139 0.049 0.007 0.057 1.60 0.15 One Point 100.0
0.09 40.00 59 0.110 0.110 0.000 0.030 0.000 0.000 1.20 0.00 Right
Bank
4.08 3.36 2.64 1.92 distance (m)
0.4
0.3
0.2
0.1
1 2
13
14 15
WELB WERB
ECOWISE Environmental
Station: BICKHAM SITE 2 Gauging No: 1.0 Date: 10/08/2007 00:00
VarFrom: 100 - Stream Water Level (metres) VarTo: 141 - Stream
Discharge (megalitres per day) Meter: 85-29 85291 Fan: 1 Method: WA
- Wading Quality: 150 - Data not yet quality coded - Hydsys default
Party: AM
Comments Approx 50m u/s gorge
Gauge Readings Logger Gauge Time Start (m) 0.000 0.000 00:00 End
(m) 0.000 0.000 00:00 Mean (m) 0.000 0.000
Results Name Value Units Quality Discharge 11.471 Ml/day 150 Area
0.932 m2 150 Velocity 0.142 m/s 150 Maximum Depth 0.500 m 150
Maximum Velocity 0.182 m/s 150 Slope 0.000 m 150 Mannings N 0.000
l/s 150 Wetted Perimeter 3.788 m 150 Width 0.000 ? 150 Num Sections
0.000 ? 150 Temperature 0.000 øC 150 Sigma AD 0.000 ? 150 Hydraulic
Radius 0.246 m 150 Total Error 0.000 ? 150 Turbidity 0.000 NTU
150
Rating (not found) Shift (m): 0.00 Without Shift With Shift
Discharge (Ml/day) 0.000 0.000 % Deviation 0.00 0.00
Distance Vert. Type % Estimate Obs. Depth Obs. Time Revolutions
Obs. V Vert. Velocity Sect. Vel Sect. Sect. Flow % Flow Comment
3.80 0.00 Left Bank 0.000 0.033 0.000 0.000 3.30 0.13 One Point
50.0 0.08 40.00 11 0.037 0.037 0.061 0.032 0.002 0.017 Weed u/s
3.10 0.20 One Point 100.0 0.12 40.00 42 0.084 0.084 0.122 0.047
0.006 0.050 2.90 0.27 Two Point 100.0 0.05 40.00 93 0.159 0.161
0.156 0.059 0.009 0.080 0.22 40.00 95 0.162 2.70 0.32 Two Point
100.0 0.06 40.00 69 0.125 0.151 0.157 0.070 0.011 0.096 0.26 40.00
105 0.176 2.50 0.38 Two Point 100.0 0.08 40.00 85 0.148 0.164 0.165
0.061 0.010 0.087 0.30 40.00 108 0.180 2.35 0.43 Two Point 100.0
0.09 40.00 88 0.152 0.165 0.170 0.043 0.007 0.064 0.34 40.00 107
0.179 2.25 0.43 Two Point 100.0 0.09 40.00 101 0.170 0.175 0.169
0.046 0.008 0.067 0.34 40.00 107 0.179 2.15 0.48 Two Point 100.0
0.10 40.00 89 0.153 0.164 0.165 0.049 0.008 0.070 0.38 40.00 104
0.175 2.05 0.49 Two Point 100.0 0.10 40.00 94 0.161 0.167 0.167
0.049 0.008 0.072 0.39 40.00 103 0.173 1.95 0.50 Two Point 100.0
0.10 40.00 93 0.159 0.168 0.168 0.075 0.013 0.110 0.40 40.00 105
0.176 1.80 0.50 Two Point 100.0 0.10 40.00 91 0.156 0.169 0.153
0.075 0.011 0.100 0.40 40.00 109 0.182 1.65 0.50 Two Point 100.0
0.10 40.00 54 0.102 0.137 0.145 0.059 0.009 0.074 0.40 40.00 102
0.172 1.50 0.28 Two Point 100.0 0.06 40.00 82 0.143 0.152 0.149
0.059 0.009 0.078 0.23 40.00 94 0.161 1.30 0.31 Two Point 100.0
0.06 40.00 73 0.131 0.147 0.142 0.056 0.008 0.069 0.25 40.00 96
0.163 1.10 0.25 One Point 100.0 0.15 40.00 77 0.136 0.136 0.143
0.064 0.009 0.080 0.80 0.18 One Point 100.0 0.11 40.00 87 0.151
0.151 0.117 0.043 0.005 0.043 0.50 0.11 One Point 100.0 0.07 40.00
41 0.083 0.083 0.000 0.014 0.000 0.000 0.25 0.00 Right Bank
3.09 2.38 1.67 0.96 distance (m)
0.4
0.3
0.2
0.1
1
2
3
4
5
13 14
WELB WERB
ECOWISE Environmental
Details (not found) Station: BICKHAM SITE 3 Gauging No: 1.0 Date:
26/07/2007 00:00 VarFrom: 100 - Stream Water Level (metres) VarTo:
141 - Stream Discharge (megalitres per day) Meter: 85-29 85291 Fan:
1 Method: WA - Wading Quality: 150 - Data not yet quality coded -
Hydsys default Party: am/sb
Comments Poor section, limited choice at this location
Gauge Readings Logger Gauge Time Start (m) 0.000 0.000 00:00 End
(m) 0.000 0.000 00:00 Mean (m) 0.000 0.000
Results Name Value Units Quality Discharge 9.592 Ml/day 150 Area
2.052 m2 150 Velocity 0.054 m/s 150 Maximum Depth 0.460 m 150
Maximum Velocity 0.136 m/s 150 Slope 0.000 m 150 Mannings N 0.000
l/s 150 Wetted Perimeter 6.416 m 150 Width 0.000 ? 150 Num Sections
0.000 ? 150 Temperature 0.000 øC 150 Sigma AD 0.000 ? 150 Hydraulic
Radius 0.320 m 150 Total Error 0.000 ? 150 Turbidity 0.000 NTU
150
Rating (not found) Shift (m): 0.00 Without Shift With Shift
Discharge (Ml/day) 0.000 0.000 % Deviation 0.00 0.00
Distance Vert. Type % Estimate Obs. Depth Obs. Time Revolutions
Obs. V Vert. Velocity Sect. Vel Sect. Sect. Flow % Flow Comment
3.00 0.00 Left Bank 40.00 0.000 0.038 0.000 0.000 3.50 0.15 One
Point 50.0 0.09 40.00 21 0.052 0.052 0.055 0.122 0.007 0.070 3.90
0.46 Three Point 100.0 0.09 40.00 34 0.072 0.058 0.059 0.178 0.010
0.109 0.28 40.00 22 0.054 0.37 40.00 18 0.048 4.30 0.43 Three Point
100.0 0.09 40.00 46 0.090 0.060 0.053 0.129 0.007 0.072 Large roc
0.26 40.00 27 0.061 Large roc 0.34 40.00 5 0.028 Large roc 4.60
0.43 Three Point 100.0 0.09 40.00 27 0.061 0.047 0.030 0.129 0.004
0.040 Large roc 0.26 40.00 20 0.051 Large roc 0.34 40.00 5 0.028
Large roc 4.90 0.43 Three Point 100.0 0.09 40.00 12 0.039 0.013
0.006 0.126 0.001 0.008 Large roc 0.26 40.00 0 0.000 Large roc 0.34
40.00 0 0.000 Large roc 5.20 0.41 Three Point 100.0 0.08 40.00 0
0.000 0.000 0.030 0.385 0.012 0.120 Large roc 0.25 40.00 0 0.000
Large roc 0.33 40.00 0 0.000 Large roc 6.20 0.36 Three Point 100.0
0.07 40.00 33 0.070 0.060 0.069 0.103 0.007 0.074 0.22 40.00 35
0.074 0.29 40.00 10 0.036 6.50 0.33 Two Point 100.0 0.07 40.00 48
0.093 0.078 0.088 0.099 0.009 0.090 0.26 40.00 28 0.063 6.80 0.33
Two Point 100.0 0.07 40.00 51 0.098 0.097 0.099 0.103 0.010 0.107
0.26 40.00 50 0.096 7.10 0.36 Two Point 100.0 0.07 40.00 65 0.119
0.102 0.107 0.113 0.012 0.126 0.29 40.00 42 0.084 7.40 0.39 Three
Point 100.0 0.08 40.00 53 0.101 0.113 0.098 0.168 0.016 0.171 0.23
40.00 53 0.101 0.31 40.00 77 0.136 7.80 0.45 Three Point 100.0 0.09
40.00 53 0.101 0.083 0.070 0.231 0.016 0.170 0.27 40.00 39 0.080
0.36 40.00 31 0.067 8.40 0.32 Two Point 50.0 0.06 40.00 31 0.067
0.058 0.000 0.128 0.000 0.000 0.26 40.00 19 0.049 9.20 0.00 Right
Bank 40.00 0
3 4.24 5.48 6.72 7.96 9.2 distance (m)
0.4
0.3
0.2
0.1
1
WELB WERB
ECOWISE Environmental
Details (not found) Station: BICKHAM SITE 4 Gauging No: 1.0 Date:
26/07/2007 00:00 VarFrom: 100 - Stream Water Level (metres) VarTo:
141 - Stream Discharge (megalitres per day) Meter: 85-29 85291 Fan:
1 Method: WA - Wading Quality: 150 - Data not yet quality coded -
Hydsys default Party: AM
Comments Approx 70m d/s big pool
Gauge Readings Logger Gauge Time Start (m) 0.000 0.000 00:00 End
(m) 0.000 0.000 00:00 Mean (m) 0.000 0.000
Results Name Value Units Quality Discharge 10.627 Ml/day 150 Area
0.554 m2 150 Velocity 0.222 m/s 150 Maximum Depth 0.380 m 150
Maximum Velocity 0.409 m/s 150 Slope 0.000 m 150 Mannings N 0.000
l/s 150 Wetted Perimeter 2.661 m 150 Width 0.000 ? 150 Num Sections
0.000 ? 150 Temperature 0.000 øC 150 Sigma AD 0.000 ? 150 Hydraulic
Radius 0.208 m 150 Total Error 0.000 ? 150 Turbidity 0.000 NTU
150
Rating (not found) Shift (m): 0.00 Without Shift With Shift
Discharge (Ml/day) 0.000 0.000 % Deviation 0.00 0.00
Distance Vert. Type % Estimate Obs. Depth Obs. Time Revolutions
Obs. V Vert. Velocity Sect. Vel Sect. Sect. Flow % Flow Comment
3.90 0.00 Left Bank 0.000 0.015 0.000 0.000 3.80 0.29 Two Point
50.0 0.06 40.00 231 0.355 0.360 0.367 0.029 0.011 0.102 0.23 40.00
237 0.364 3.70 0.30 Two Point 100.0 0.06 40.00 234 0.360 0.375
0.317 0.031 0.010 0.092 0.24 40.00 256 0.391 3.60 0.32 Two Point
100.0 0.06 40.00 159 0.253 0.258 0.247 0.032 0.008 0.074 0.26 40.00
166 0.263 3.50 0.32 Three Point 100.0 0.06 40.00 151 0.242 0.235
0.206 0.035 0.007 0.068 0.19 40.00 147 0.236 0.26 40.00 142 0.229
3.40 0.38 Three Point 100.0 0.08 40.00 50 0.096 0.176 0.226 0.034
0.008 0.071 0.23 40.00 120 0.197 0.30 40.00 146 0.234 3.30 0.29 Two
Point 100.0 0.06 40.00 154 0.246 0.275 0.296 0.028 0.008 0.078 0.23
40.00 195 0.304 3.20 0.27 Two Point 100.0 0.05 40.00 197 0.307
0.316 0.317 0.030 0.009 0.089 0.22 40.00 210 0.326 3.10 0.33 Two
Point 100.0 0.07 40.00 174 0.274 0.317 0.325 0.033 0.011 0.101 0.26
40.00 234 0.360 3.00 0.33 Three Point 100.0 0.07 40.00 119 0.196
0.334 0.272 0.033 0.009 0.083 Rock u/s 0.20 40.00 259 0.395 0.26
40.00 269 0.409 2.90 0.32 Three Point 100.0 0.06 40.00 67 0.122
0.210 0.208 0.031 0.006 0.060 Rock u/s 0.19 40.00 57 0.107 0.26
40.00 264 0.402 2.80 0.29 Three Point 100.0 0.06 40.00 9 0.034
0.205 0.239 0.026 0.006 0.058 0.17 40.00 143 0.230 0.23 40.00 227
0.350 2.70 0.23 One Point 100.0 0.14 40.00 173 0.273 0.273 0.263
0.023 0.006 0.057 2.60 0.23 One Point 100.0 0.14 40.00 159 0.253
0.253 0.239 0.032 0.008 0.073 2.45 0.20 One Point 100.0 0.12 40.00
140 0.226 0.226 0.143 0.030 0.004 0.040 2.30 0.20 One Point 100.0
0.12 40.00 26 0.060 0.060 0.092 0.031 0.003 0.027 Rock u/s 2.15
0.22 One Point 100.0 0.13 40.00 68 0.124 0.124 0.121 0.032 0.004
0.037 2.00 0.21 One Point 100.0 0.13 40.00 65 0.119 0.119 0.141
0.035 0.005 0.047 1.80 0.14 One Point 50.0 0.08 40.00 96 0.163
0.163 0.000 0.014 0.000 0.000 1.60 0.00 Right Bank
3.44 2.98 2.52 2.06 distance (m)
0.4
0.3
0.2
0.1
1 2 3 4
WELB WERB
ECOWISE Environmental
Station: BICKHAM SITE 5 Gauging No: 1.0 Date: 26/07/2007 00:00
VarFrom: 100 - Stream Water Level (metres) VarTo: 141 - Stream
Discharge (megalitres per day) Meter: 85-29 85291 Fan: 1 Method: WA
- Wading Quality: 150 - Data not yet quality coded - Hydsys default
Party: am
Comments Approx 60m u/s rockbank @ bcsw4
Gauge Readings Logger Gauge Time Start (m) 0.000 0.000 00:00 End
(m) 0.000 0.000 00:00 Mean (m) 0.000 0.000
Results Name Value Units Quality Discharge 12.149 Ml/day 150 Area
0.968 m2 150 Velocity 0.145 m/s 150 Maximum Depth 0.500 m 150
Maximum Velocity 0.216 m/s 150 Slope 0.000 m 150 Mannings N 0.000
l/s 150 Wetted Perimeter 3.874 m 150 Width 0.000 ? 150 Num Sections
0.000 ? 150 Temperature 0.000 øC 150 Sigma AD 0.000 ? 150 Hydraulic
Radius 0.250 m 150 Total Error 0.000 ? 150 Turbidity 0.000 NTU
150
Rating (not found) Shift (m): 0.00 Without Shift With Shift
Discharge (Ml/day) 0.000 0.000 % Deviation 0.00 0.00
Distance Vert. Type % Estimate Obs. Depth Obs. Time Revolutions
Obs. V Vert. Velocity Sect. Vel Sect. Sect. Flow % Flow Comment
3.80 0.00 Left Bank 0.000 0.018 0.000 0.000 3.60 0.18 One Point
50.0 0.11 40.00 97 0.165 0.165 0.180 0.048 0.009 0.071 3.30 0.14
One Point 100.0 0.08 40.00 118 0.195 0.195 0.205 0.042 0.009 0.071
3.00 0.14 One Point 100.0 0.08 40.00 133 0.216 0.216 0.208 0.034
0.007 0.058 2.80 0.20 One Point 100.0 0.12 40.00 122 0.200 0.200
0.179 0.014 0.003 0.021 Edge of l 2.75 0.36 Two Point 100.0 0.07
40.00 64 0.118 0.158 0.164 0.060 0.010 0.081 0.29 40.00 121 0.199
2.60 0.44 Two Point 100.0 0.09 40.00 89 0.153 0.169 0.179 0.067
0.012 0.099 0.35 40.00 111 0.185 2.45 0.46 Two Point 100.0 0.09
40.00 106 0.178 0.188 0.185 0.071 0.013 0.107 0.37 40.00 121 0.199
2.30 0.48 Two Point 100.0 0.10 40.00 92 0.158 0.182 0.175 0.073
0.013 0.106 0.38 40.00 126 0.206 2.15 0.50 Two Point 100.0 0.10
40.00 68 0.124 0.169 0.165 0.072 0.012 0.098 0.40 40.00 132 0.215
2.00 0.46 Three Point 100.0 0.09 40.00 54 0.102 0.161 0.156 0.069
0.011 0.088 0.28 40.00 101 0.170 0.37 40.00 128 0.209 1.85 0.46
Three Point 100.0 0.09 40.00 59 0.110 0.151 0.151 0.065 0.010 0.080
0.28 40.00 99 0.168 0.37 40.00 104 0.175 1.70 0.40 Two Point 100.0
0.08 40.00 75 0.133 0.152 0.146 0.079 0.012 0.095 0.32 40.00 101
0.170 1.50 0.39 Two Point 100.0 0.08 40.00 55 0.104 0.140 0.130
0.076 0.010 0.081 0.31 40.00 105 0.176 1.30 0.37 Three Point 100.0
0.07 40.00 31 0.067 0.120 0.100 0.080 0.008 0.065 0.22 40.00 72
0.129 0.30 40.00 97 0.165 1.00 0.16 One Point 100.0 0.10 40.00 39
0.080 0.080 0.064 0.048 0.003 0.025 Weed u/s 0.70 0.16 One Point
100.0 0.10 40.00 18 0.048 0.048 0.024 0.048 0.001 0.009 Weed u/s
0.40 0.16 One Point 50.0 0.10 40.00 0 0.000 0.000 0.000 0.004 0.000
0.000 no flow 0.35 0.00 Right Bank
3.11 2.42 1.73 1.04 distance (m)
0.4
0.3
0.2
0.1
1
the Blandford Gauge for
Dates Corresponding to Flow
Gauging on “South Bickham”
0.7495
0.75
0.7505
0.751
0.7515
0.752
0.7525
0.753
0.7535
0.754
0.7545
0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00
13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00
23:00
H ei
gh t (
m et
re s)
0.7534
0.7536
0.7538
0.754
0.7542
0.7544
0.7546
0.7548
0.755
0.7552
0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00
13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00
23:00
H ei
gh t (
m et
re s)
Assignment No. 21667 Page 1 of 4
Bickham Coal Project Response to the PAC, Question 3
0.769
0.7695
0.77
0.7705
0.771
0.7715
0.772
0.7725
0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00
13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00
23:00
H ei
gh t (
m et
re s)
0.7665
0.767
0.7675
0.768
0.7685
0.769
0.7695
0.77
0.7705
0.771
0.7715
0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00
13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00
23:00
H ei
gh t (
m et
re s)
Assignment No. 21667 Page 2 of 4
Bickham Coal Project Response to the PAC, Question 3
0.565
0.57
0.575
0.58
0.585
0.59
0.595
0.6
0.605
0.61
0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00
13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00
23:00
H ei
gh t (
m et
re s)
0.565
0.57
0.575
0.58
0.585
0.59
0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00
13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00
23:00
H ei
gh t (
m et
re s)
Assignment No. 21667 Page 3 of 4
Bickham Coal Project Response to the PAC, Question 3
0.91
0.915
0.92
0.925
0.93
0.935
0.94
0.945
0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00
13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00
23:00
H ei
gh t (
m et
re s)
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00
13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00
23:00
H ei
gh t (
m et
re s)
Assignment No. 21667 Page 4 of 4
Bickham Coal Project
20100315_21667_Response to PAC Q4.docx Page 1 15 March 2010
Rainfall and Runoff Modelling
Question 4
4. Given the variability inherent in rainfall runoff processes and
the difficulties in measuring yield
from mine catchment areas, such as overburden dumps and mine pits,
the PAC requests rainfall
and resultant runoff sequences from modelled overburden, haul road
and mine pit catchments.
This information could be provided as daily sequences of rainfall
(mm), overburden runoff
(mm), haul road runoff (mm) and mine pit runoff (mm) over the
complete 129 year record.
Given the possible implications of excess pit inflows the PAC
requests further sensitivity
assessment of runoff inflows to the mine pits based on a model
configured to give what BCC
considers to be the upper limit of credible mine pit catchment
yield that could be generated
from the mine pit catchment based on experience with mine pits
under different climatic
conditions in similar mining operations in NSW. Of particular
relevance to the PAC are the
resultant implications for in-pit storage of water and risk of
interruption to the mine schedule.
Response
1 Introduction
The Australian Water Balance Model (AWBM) is used in the WRA to
establish the surface water
runoff from the proposed mine. The AWBM and the climate data and
runoff parameters used to
characterise the mine are described in the WRA (Appendix 19 Section
3).
The surface water runoff predicted by the AWBM is a key input to
the daily water balance model
created for the mine. Therefore, the daily water balance model is
potentially sensitive to runoff
parameters selected for use in the AWBM. The WRA (Appendix 19 Table
3.6) assessed the
sensitivity of the model results to changes in the AWBM parameters
by varying the parameters by
±20% and analysing the effect on runoff as a percentage of
rainfall. This assessment found that
the percentage runoff to not be very sensitive to the adopted
parameters.
In response to Question 7, BCC has undertaken additional AWBM runs
using alternative runoff
parameters to test the sensitivity of the predicted runoff inflows
to the mine pit. The method
followed to undertake these model runs included:
Reviewing a number of sources including surface water assessment
reports accompanying
coal mining applications currently on public exhibition (and
obtainable from the NSW
Department of Planning web site) to identify any additional data
that could be used to
benchmark the runoff characteristics of coal mine pits:
“Water Quality and Discharge Predictions for Final Void and Spoil
Catchments” (ACARP
Project C7007, 2001);
“Surface Water Assessment: Ashton Coal South East Open Cut
Project”;
“Ravensworth Operations Project: Surface Water Assessment”;
“Continued Operations at Baal Bone Colliery: Mine Water
Balance”;
“Water Resource Assessment: Cumnock Wash Plant Mining and
Rehabilitation Project”.
Discussions with other consultants to identify appropriate
alternative runoff parameters for
coal mine pits which are considered to be at the upper limit of
credible mine pit catchment
yield;
20100315_21667_Response to PAC Q4.docx Page 2 15 March 2010
Undertaking additional AWBM runs for the four main land use types
present at each stage
of the project, namely „natural, „recent or „raw overburden,
„established or „rehabilitated
overburden, and haul roads and pits
Plotting runoff versus rainfall for each of the additional AWBM
runs and visually comparing
these plots with those from the original AWBM runs for the
WRA.
Further details on the additional model runs and an analysis of the
results of the sensitivity
assessment are provided in the following sections.
2 Runoff Parameters
The runoff parameters used in the original AWBM runs are provided
in the WRA (Appendix 19
Table 3.5) and are reproduced in Table 1. The sources for these
parameters and a justification for
their selection are also provided in the WRA (Appendix 19 Section
3.2).
The ACARP report (referenced above) only provides runoff parameters
for overburden dumps, not
active mine pits. None of the surface water assessment reports
contained in coal mining
applications currently available on the Department of Planning web
site provides details of the
runoff characteristics assumed for water balance analysis or
sufficient information (catchment area
and volume of runoff) that could be used to back calculate an
inferred runoff percentage.
Alternative runoff parameters appropriate to the Bickham site were
obtained by from JP
Environmental for the Mount Thorley Warkworth project. Mount
Thorley Warkworth is an
integrated operation of two open cut mines located adjacent to each
other 15 kilometres south
west of Singleton in the Hunter Valley. Both mines began operation
in 1981 (Coal & Allied 2010).
The runoff parameters provided by JP Environmental are based on a
calibration run performed for
the 2007 -2008 calendar years using actual storage levels. This
period included a significant storm
event in June 2007. On 1 January 2007, the Mount Thorley Warkworth
mine had been in extreme
drought conditions for about 18 months, all pits were completely
dewatered as were most site
dams, and the site was maintaining production rates only by pumping
from the Hunter River. Most
of the site storages that still contained water had known
stage-storage relationships allowing a
good estimate to be made of a small volume of water. At the end of
2008, the site held very large
volumes of water, which had a reasonably well defined stage storage
curve (JP Environmental
2009).
JP Environmental undertook model calibration against these storage
points and others by adjusting
the soil moisture capacity for the various catchment types in the
AWBM model. Calibration was not
undertaken on individual land uses, but rather total site inventory
(JP Environmental 2009).
The runoff parameters for the Mt Thorley project are set out in
Table 2. These parameters have
been adopted for purposes of re-assessment of the site water
balance for the mine pits at Bickham
(see response to Question 11 for details).
Bickham Coal Project
20100315_21667_Response to PAC Q4.docx Page 3 15 March 2010
Table 1 - Runoff Parameters – Original AWBM Runs
Parameter Land use
Natural Haul roads
Table 2 - Runoff Parameters – from Mt Thorley
Parameter Land use
Natural Haul roads
Bickham Coal Project
20100315_21667_Response to PAC Q4.docx Page 4 15 March 2010
3 Sensitivity Assessment
A simple sensitivity assessment was conducted by visually comparing
the trend lines on the runoff
versus rainfall plots for each pair of original and additional AWBM
runs for the four main land use
types.
The compared runoff versus rainfall plots are provided in Appendix
A. The plots show an almost
doubling of runoff for the natural and road and pit land uses when
the Mt Thorley parameters are
used as compared to the parameters used in the WRA. The plots for
recent and established
overburden land uses indicates less and similar runoff respectively
when compared to the
parameters used in the WRA.
Comparisons of the overall runoff from different land surfaces
expressed as a simple percentage of
rainfall are presented in Table 3.
Table 3 - Runoff as a Percentage of Rainfall
Land Use Original Analysis Mt Thorley Parameters
Natural 7.0% 12.3%
Raw Overburden 21.2% 8.0%
Established Overburden 15.9% 13.1%
The data in Table 3 indicates differences between the runoff
generated with the two sets of
parameters, with the Mt Thorley parameters giving almost double the
runoff for „natural and „roads
and pits, but less than half the runoff for „raw overburden.
However, as noted earlier, the
derivation of the parameters for Mt Thorley was based on total site
inventory of land uses and
areas, rather than individually.
The rainfall versus runoff plots and the data in Table 3 indicate
that for „natural land use, the
parameters derived from Mt Thorley gives runoff percentage of 12.3%
which is considered
unrealistic for the Bickham situation where the runoff for Kingdon
Ponds at Parkville is only 7% of
rainfall.
Any consideration of the effect of different runoff parameters on
the overall water balance must
also take account of the catchment area represented by the
different land uses in Years 13-18
which represent the time when dewatering flow is highest and the
total contributing catchment
area is the largest. For Years 13-18, the average areas (and
percentages) that comprise the pit
catchment are:
Raw overburden 6 ha (4%)
Established overburden 29 ha (16%)
It can be seen that by adopting the Mt Thorley AWBM parameters for
all land uses, an additional
element of conservatism is introduced to the analysis because the
runoff from the „natural land
surfaces, which comprise 30% of the catchment is about double that
which would occur if the
locally calibrated parameters were adopted.
Bickham Coal Project
20100315_21667_Response to PAC Q4.docx Page 5 15 March 2010
For purposes of re-assessment of the mine water management strategy
reported in the response
to Question 11, the runoff values using the Mt Thorley parameters
have been adopted. The runoff
generated using these parameters is considered to represent a
credible upper limit of runoff to
from the catchments draining to the mine pits.
Copies of the electronic output files for each of the land use
types for the original assessment and
the updated assessment are provided separately.
4 References
Coal & Allied 2010, Mount Thorley Warkworth website, accessed
10 March 2010,
http://www.coalandallied.com.au/333_mount_thorley_warkworth.asp
JP Environmental 2009, Appendix A OPSIM Model Calibration and
Operation
Mine Life Model v7 Rainfall v Runoff Plots
y = 0.0033x2 - 0.0364x + 0.092
N at
ur al
ru no
ff (m
ill im
et re
Natural runoff
Trendline (polynomial)
N at
ur al
ru no
ff (m
ill im
et re
s/ da
Natural runoff
trendline (polynomial)
@
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Bickham Coal Project Assignment No. 21667
Mine Life Model v7 Rainfall v Runoff Plots
y = 0.0037x2 + 0.0247x + 0.3755
Ru no
ff fr
om re
ce nt
o ve
rb ur
de n
(m ill
im et
re s)
Runoff from recent overburden
Ru no
ff fr
om re
ce nt
o ve
rb ur
de n
(m ill
im et
re s/
da y)
Daily rainfall (millimetres)
RecOB Runoff v Rainfall, 1878-2006 [2010 Additional] Runoff from
recent overburden
Trendline (polynomial)
@
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1
Bickham Coal Project Assignment No. 21667
Mine Life Model v7 Rainfall v Runoff Plots
y = 0.004x2 - 0.017x + 0.3099
Ru no
ff fr
om e
st ab
lis he
d ov
er bu
rd en
(m ill
im et
re s/
da y)
Daily rainfall (millimetres)
Est O/B Runoff v Rainfall, 1878 - 2006 [2009 Original] Runoff from
established overburden
Trendline (polynomial)
Ru no
ff fr
om e
st ab
lis he
d ov
er bu
rd en
(m ill
im et
re s/
da y)
Runoff from established overburden
Trendline (polynomial)
@
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1
Bickham Coal Project Assignment No. 21667
Mine Life Model v7 Rainfall v Runoff Plots
y = 0.0036x2 + 0.188x - 0.1449
Ru no
ff fr
om th
e pi
t ( m
ill im
et re
s/ da
Runoff from the pit
Ru no
ff fr
om th
e pi
t ( m
ill im
et re
s/ da
Roads & Pits runoff
Trendline (polynomia