yandicoogina baseline hydrology

Yandicoogina baseline hydrology of 60

Resource Development Surface Water Management

Baseline hydrology assessment for Yandicoogina

discharge

02 April 2012 (Update to Report – Baseline hydrology assessment for Marillana Creek discharge released 4 May 2010)

Future expansion at RTIO Yandicoogina has the potential to increase the volume of surplus

water generation and discharge into Marillana and Weeli Wolli Creeks. A baseline

hydrological/hydraulic assessment was carried out to access the existing situation and

movement of discharged water along the creek systems and to predict the likely behaviour of

the released water for various discharge scenarios. Surplus water is discharged by BHPBIO

and RTIO Yandicoogina mine operations at several locations along Marillana Creek (BHPBIO

discharge outlet is located 2 km up gradient of the RTIO Oxbow deposit; RTIO discharge

network is located adjacent to the Junction Central mine) and two outlets by RTIO Hope

Downs 1 and Yandicoogina operations in Weeli Wolli Creek (Hope Downs 1 discharge outlet is

located 500 m up gradient of the Weeli Wolli Spring; RTIO Discharge Outlet 6 is positioned

adjacent to the Junction South East mine). In December 2009, the total average discharge

rate to the creek systems from all three mining operations was 116 ML/day or 42 GL/year.

The assessment demonstrated that historically discharged water would not have extended past

the Marillana Creek catchment outlet at the confluence with Weeli Wolli Creek; hence

anecdotally no flow contribution to Weeli Wolli would have been expected. This suggests the

wetting front in Weeli Wolli Creek is likely to have resulted from surplus water discharged

from the Hope Downs 1 mine operation.

The average maximum steady state inundation or discharge footprint produced from the total

average discharge, from 1998 to 2009, was expected to extend approximately 2.5 km down

gradient from the confluence of Weeli Wolli and Marillana Creeks. On the other hand, the

discharge footprint would extend 5.5 km downstream from the confluence if 60 GL/year (peak

discharge from 1998 to 2009) of surplus water was released at a constant rate into the creek

systems.

A discharge footprint of 35.4 km from the BHPBIO discharge outlet and 36.1 km from the

Hope Downs 1 discharge outlet or 16.3 km down gradient from the Weeli Wolli – Marillana

Creek confluence was estimated for the maximum modelled 110 GL/year regional surplus

discharge (based on existing infrastructure). An option to relocate the discharge location in

Marillana Creek down gradient from the mine operations was also investigated. Modelling

indicated that the footprint distance would extend from approximately 6.7 km to 17.3 km

down gradient from the Weeli Wolli – Marillana Creek confluence for modelled volumes 55

GL/year to 110 GL/year.

Due to the dynamic nature of the Weeli Wolli Creek system, the creek channel and in

particular the section that drains the alluvial plain is capable of changing course during large

flood events. This type of event would modify the existing drainage flow path of the

discharged water and alter the course of the discharge footprints.


Contents page

Introduction 3

1. Issue 3

2. Objectives 3

Catchment characteristics 4

3. Hydrology 4

4. Rainfall 5

5. Hydrogeology 7

6. Alluvium characteristics 8

7. Riparian vegetation 11

7.1 Mapped vegetation 11

7.2 Evapotranspiration 14

Discharge modelling 16

8. Modelling approach 16

8.1 Defining the discharge footprint 16

8.2 Surface water – groundwater connectivity 18

9. Discharge water balance calculations 20

9.1 Methodology 20

10. Modelling scenarios 28

10.1 Existing discharge regime 28

10.1.1 Scenario 1: Comparison of observed and predicted wetting fronts 28

10.1.2 Scenario 2: Average discharge between 2007 and 2009 29

10.1.3 Scenario 3: Peak discharge between 1998 and 2009 29

10.2 Proposed discharge scenarios 29

10.2.1 Scenario 4: Discharge rate options – 60 GL/year 29

10.2.2 Scenario 5: Discharge rate options – 90 GL/year 29

10.2.3 Scenario 6: Relocation of Marillana Creek discharge outlets 29

11. Modelling results 30

11.1 Existing discharge footprints 30

11.2 Proposed discharge footprints 33

11.2.1 Scenarios 4 and 5 33

11.2.2 Scenario 6 35

Conclusion 40

Appendix A – Base case output 42

Appendix B – Scenario output 47

Addendums– Scenario 7 to 9 including BHPBIO Jinidi 52

References 60


Introduction

1. Issue Surplus water is generated as a result of mining below the groundwater table. The volume and

rate of surplus water generation will be determined by the difference between the rate at which

site and other parties can use the water and the rate of abstraction. The current total

abstraction rate for Yandicoogina Junction Central (JC) and Junction South East (JSE) is 35

GL/year, with the potential to increase to a maximum 55 GL/year as a result of expansion and

development of the Junction South West (JSW) and Oxbow deposits.

Management of water on Rio Tinto sites follows strict environmental and water use standards

(refer to Rio Tinto Environmental Standards). These standards align with the Western

Australian State Government Department of Water hierarchy of disposal options informal

regulatory guidelines (Bessan Consulting Services, 2007) that recommend (in order of

preference):

Use on site;

Transfer to another site or industrial location;

Re-injection;

Controlled discharge to surface (irrigation); and

Uncontrolled discharge to surface (creek discharge).

Any surplus water not utilised in the first four strategies is currently being discharged into

Marillana and Weeli Wolli Creeks.

Discharge of surplus water from the BHPBIO Yandicoogina mine operation into Marillana

Creek began in May 1992. In 1998 RTIO started releasing surplus water into Marillana Creek

and by December 2006 the combined operations were discharging at an average rate of 34

ML/day. Release of surplus water into Weeli Wolli Creek began in 2007 with expansion of the

JSE mine and development of the Hope Downs 1 operation up gradient of Yandicoogina. By

December 2009, the combined average discharge rate to Marillana and Weeli Wolli Creeks

from all three operations was 116 ML/day.

2. Objectives The purpose of this study was to predict the hydrological reaction of the creek systems to

artificial discharge. The specific objectives of the assessment were:

To characterise the stream morphology of sections of Marillana and Weeli Wolli Creeks

downstream of the discharge outlets. This was accomplished by reviewing the stream

pattern, river/floodplain geometry, soil profile/geological logs, vegetation patterns and

community distribution, and other characteristics of the receiving creeks to establish

representative “reaches”.

To determine the hydraulic characteristics associated with different volumes of water

released into the system. This work was accomplished in order to determine the capacity

and reaction (water movement) of the creeks at different discharge volumes.

To establish the area over which the released water could travel (or discharge footprint).


Catchment characteristics

The dearth of hydrological data in the Pilbara, especially related to small and medium sized

catchments, their stream flow and rainfall distribution patterns, makes it impossible to use

standard hydrology assessment methodologies to determine surface water flow characteristics

in local Pilbara catchments. To overcome this limitation and to provide a methodology for

estimating the potential flow conditions of artificial discharge into ephemeral Pilbara creeks,

hydroecology techniques for evaluating water movement have been adopted.

Hydroecology is the inter-disciplinary study of the interactions between ecological processes

and water movement. For the purpose of this study, information that could be extracted from

the Pilbara landscape to help describe baseline hydrological characteristics, in the absence of

historical stream flow or climate series data, included: vegetation patterns and communities in

the riparian zone, pool location/absence and water quality, geomorphology of the creek bed,

banks and floodplain, and soil/regolith geology properties and patterns (particularly as

recorded in satellite remote sensing imagery). These catchment characteristics are described

below and are subsequently used to define the inputs to the discharge modelling.

3. Hydrology The Weeli Wolli Creek regional catchment covers an area of approximately 4,000 km2. The

upper Weeli Wolli Creek catchment, up gradient of the Hope Downs 1 mine, is characterised

by relatively wide, flat plains of gentle gradient, surrounded by rugged hills of outcropping

Marra Mamba Iron and Brockman Iron Formation. The Creek and its tributaries drain in a

north easterly direction past the Hope Downs 1 mine site, converging at a narrow valley

system. Weeli Wolli Spring is located at the mouth of the valley, approximately 10 km down

gradient from the Hope Downs 1 mine site. The Creek continues its path downstream into the

lower Weeli Wolli Creek catchment, joins with Marillana Creek to the west and drains onto a

wide alluvial floodplain 20 to 30 km across in the Fortescue Valley, producing a meandering

channel that can alter its course following large flood events. The flows terminate at the

Fortescue Marsh, an internally draining basin of the Upper Fortescue River catchment.

Marillana Creek, a major tributary of the Weeli Wolli Creek system, has a total catchment area

of 2,230 km2. The headwaters rise from the high relief areas of Hamersley Range where the

Creek drains in an east and north easterly direction into the Munjina Claypan. The Claypan,

an internally draining basin, has a total area of approximately 274 km2. It is subject to

periodic inundation following rainfall events and has the potential to retain surface water

flows for lower flood events, ≤ 1 in 10 year annual recurrence interval (ARI). Surface water

exceeding the internal holding capacity of the basin spills south east into the lower Marillana

Creek catchment. The lower Marillana Creek drains in an easterly direction through the

existing BHPBIO and RTIO Yandicoogina operations before merging with Weeli Wolli Creek.

The Weeli Wolli regional catchment contains four flow gauging stations: 1) Flat Rocks on

Marillana Creek (WRC number 708001), approximately 27 km up gradient of the current

RTIO Yandicoogina mine operation; 2) Weeli Wolli Spring (WRC number 708016); 3) Tarina

on Weeli Wolli Creek (WRC number 708014), approximately 5 km downstream from Weeli

Wolli Spring and 4) Waterloo Bore on Weeli Wolli Creek (WRC number 708013), 7 km

downstream from the Weeli Wolli/Marillana intersection. Daily flow data for the gauging

stations are available from 1970s to present, with occasional missing data.


The regional hydrology of the Marillana Creek catchment assessed in 2008 (RTIO) estimated

the natural peak flow volumes at Oxbow, the intersection between the BHPBIO and RTIO

Yandicoogina operations, to be 70 m3/s for a 2 year ARI event and greater than 2,000 m3/s for

a 100 year ARI flood. Gauging information from the Tarina and Waterloo Bore gauging

stations on Weeli Wolli Creek were extracted and flood frequency analysis performed (RTIO,

2009). Peak flow volumes for Weeli Wolli Creek at Tarina are expected to exceed 120 m3/s

and 2,200 m3/s for a 2 year and 100 year ARI flood events, while the full Weeli Wolli Creek at

Waterloo Bore (including flow contribution from Marillana Creek) is expected to reach 180

m3/s and 10,000 m3/s for 2 year and 100 year ARI floods.

Figure 1: Weeli Wolli Creek regional catchment

4. Rainfall Using the Köppen climate classification scheme1 based on temperature and rainfall, the Weeli

Wolli Creek regional catchment is described as grassland: hot (persistently dry). Rainfall

records are available from Flat Rocks (1972 – present), Munjina (1969 – present), Tarina

(1985 – present), Waterloo Bore (1985 – present) and Wonmunna (1984 – present); locations

of the gauging stations are illustrated in Figure 1. Average monthly rainfall for the region is

provided in Figure 2. The average annual rainfall for the catchment is estimated to be 402

mm. Rainfall is episodic and highly variable between years (Figure 3), with annual recorded

rainfall for the region between 180 mm and 810 mm.

1 http://www.bom.gov.au/lam/climate/levelthree/ausclim/koeppen2.htm


0

20

40

60

80

100

120

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

Rain

fall (

mm

)

Flat Rocks Munjina Tarina Waterloo Bore Wonmunna

Figure 2: Average monthly rainfall for Weeli Wolli Creek regional catchment.

0

200

400

600

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1200

1964

1968

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1976

1980

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1988

1992

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Rain

fall (

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Flat Rocks Munjina Tarina

Waterloo Bore Wonmunna Average annual rainfall

Figure 3: Annual rainfall data series (1969 – 2008) for gauging stations within the Weeli Wolli Creek regional

catchment.

The majority of rainfall occurs during the hottest months, between December and March,

resulting from cyclonic lows. Winters are dry and mild in comparison with lighter, winter

rainfall expected in June/July each year. Larger than average annual rainfall were recorded in

the Weeli Wolli Creek catchment particularly in 1973, 1975, 1995 - 2000 and in 2006,

potentially under the influence of significant cyclonic activities. Seven major cyclones have

passed in vicinity of the catchment for the period 1970 to present; Kerry in January 1973, Joan

in December 1975, Bobby in January 1995, John in December 1999, Norman in February

2000, Clare in January 2006 and Emma in February 2006.

The annual average evaporation (dry bulb) rate recorded in Yandicoogina is 1791 mm/year,

which exceeds the mean annual rainfall, keeping the landscape typically arid. The average

annual pan evaporation for the region (from Department of Agriculture Western Australia,


2003) is approximately 3500 mm. Due to the low rainfall (brief wet season) and large

evaporation, water courses flow, if at all, for only brief periods.

5. Hydrogeology Hydrogeology of the Yandicoogina region is dominated by three types of aquifer:

Unconfined, superficial/Quaternary formations of alluvial deposits;

Unconfined, fractured Channel Iron Deposits (CID);

Confined, fractured bedrock.

These aquifers are recharged primarily by direct infiltration of rainfall and via creek bed

alluvials as a result of surface water flows during and/or following a storm event. The latest

hydrogeological conceptual model for the Yandicoogina region (Yandicoogina Hydrogeological

Field Program Report, RTIO-PDE-0071209) highlights the hydraulic connection between the

superficial alluvium and the CID.

The natural depth to groundwater table (pre-mining) in the Yandicoogina region varies from 3

to 20 m below ground level with the general flow direction to the east within the Marillana

Creek catchment and to the northeast along Weeli Wolli Creek. The groundwater flow system

has since been modified as a result of abstraction for mine development, reinjection and/or

permanent release of surplus water into the Marillana and Weeli Wolli Creek systems.

The existing surplus water discharge outlets along Marillana and Weeli Wolli Creeks are

illustrated in Figure 4. BHP Billiton originally released surplus water into Marillana Creek at

the discharge outlet at Anniversary Drive, approximately 2 km up gradient of the Oxbow

deposit. This outlet was relocated in May 2007 and is now positioned 500 m downstream

from the BHP railway bridge. Excess water from the Junction Central (JC) mining operation

is discharged into Marillana Creek, via several outlets, adjacent to the mine. With the

expansion of the Junction South East (JSE) deposit in 2006, two additional outlets, DO5 and

DO6, were constructed to release surplus water into Marillana and Weeli Wolli Creeks.

Discharge from the Hope Downs 1 mine into Weeli Wolli Creek is released, approximately

500 m up gradient of the Weeli Wolli Spring, 12 km upstream from the JSE DO6 outlet.

Response of the groundwater table, for the period 1991 to 2010, to natural cyclonic events,

mine dewatering and surplus discharge in the Yandicoogina region are illustrated in Figure 5

and Figure 6. Bore locations of where the water level data were extracted are provided in

Figure 4. It was demonstrated that impacts resulting from surplus water discharge are

minimal compared to the natural fluctuations of the water table in response to storm and/or

cyclonic events in the region.

Weeli Wolli Spring is the only groundwater fed naturally permanent pool identified in the

study area. It provides a baseflow component to Weeli Wolli Creek at a rate of 4.2 ML/day.

Other evidence of pools within the lower Weeli Wolli Creek catchment are transient and

dependent on rainfall and surface water, with some now sustained by the surplus water

discharge.


Figure 4: Existing surplus water discharge outlets along Marillana and Weeli Wolli Creeks. The CID

boundary (brown polygon) highlights the current RTIO Yandicoogina mine areas (Junction Central and

Junction South East) and undeveloped deposits, including Oxbow, Junction South West and Billiard

North/South. Groundwater levels as shown in Figures 5 and 6 were extracted from bores represented as blue

dots in the figure.

6. Alluvium characteristics Alluvial and colluvial regolith characteristics, used as a surrogate for detailed soil information,

govern the infiltration rate and storage capacity of the creek. These characteristics also

influence the type and densities of vegetation communities developed within and adjacent to

the creek, and subsequently influence evapotranspiration within the system. In general, the

creek alluvium is comprised of interbedded layers of clays to sands and gravels to cobbles. The

coarse alluvium at the surface of the creek bed is highly permeable, hence would rapidly

recharge during creek flows (Australian Bore Consultants, 1997).

Based on geological sequences extracted from the Rio Tinto Iron Ore drillhole database,

alluvial depth within the creeks range from approximately 5 m to 30 m along Marillana Creek

and 9 m to 40 m along Weeli Wolli Creek. The alluvium is thin (possibly < 5 m thick) along a

small section of Marillana Creek, adjacent to the JC mine. This indicates shallow CID and/or

basement rocks of the Weeli Wolli Formation in and around the creek bed in this area.

Drilling in the alluvium at Weeli Wolli Creek in 1997 intersected thick sequences of tight

alluvial clay, resulted in premature termination of the monitoring bore at 4 m below ground

level (the bore is located 1.4 km up gradient of the Weeli Wolli/Marillana confluence). If

laterally continuous, the presence of this clay layer may cause perching of the watertable in

particular following significant rainfall or flood events.


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Figure 5: Response of groundwater levels to natural cyclonic events, mine dewatering and surplus water discharge at JSE and JC


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Figure 6: Response of groundwater levels to natural cyclonic events, mine dewatering and surplus water discharge at Billiard North and South along Weeli Wolli Creek


7. Riparian vegetation

7.1 Mapped vegetation

Vegetation type, distribution and density can be related to the water availability, soil depth

and conditions, and the channel morphology of a creek system. Several vegetation and flora

surveys have been conducted in the Yandicoogina region, which include the Junction Central

area by Mattiske in 1995, the Junction South East area by Biota in 2004 and the Oxbow,

Junction South West and Billiard South areas by Biota in 2009. Riparian vegetation in

Marillana Creek is dominated by woodlands of Eucalyptus camaldulensis (River Red Gum), E.

victrix (Coolibah) over low open woodlands of Melaleuca argentea (Cadjeput) and M.

glomerata. M. argentea is a groundwater dependent species, which primarily draws water

from the saturated zone below the water table. Masini (1988) suggested the presence of M.

argentea is indicative of permanent water. E. camaldulensis obtains its water from

groundwater and river flooding, with mature trees more reliant on groundwater than young.

Stands of River Red Gum are intimately associated with the surface flooding regime of the

watercourses and related groundwater flow (CSIRO, 2004). Earlier study conducted by AGC

Woodward-Clyde in 1992 concluded that the depth to groundwater is crucial to the

distribution of M. argentea within the Marillana Creek system and suggested the likely

maximum rooting depths of M. argentea is less than 5 m and that of E. camaldulensis is less

than 10 m.

Riparian vegetation species, such as Eucalyptus victrix and Acacia citrinoviridis (Black

Mulga), are commonly found in Weeli Wolli Creek within the Billiard South area. These tree

species are believed to rely on water available within the vadose zone of the soil profile above

the water table. This suggests these species prefer unsaturated soil conditions with periods of

drought broken by groundwater recharge from surface flows and/or direct infiltration of

rainfall.

Figure 7 illustrates the locations along Marillana and Weeli Wolli Creeks where photos were

taken during the helicopter trip on 22 April 2010; Figures 8 to 15 illustrate the different

vegetation types as observed during the site visit.

Riparian vegetation distribution and density within the study area are likely to vary depending

on the fluctuations of the groundwater table as a result of mining activities. Figure 16

illustrates the change in vegetation pattern in a stretch of Marillana Creek, adjacent to the

current JC mine, between 1994 and 2009. There is photographic evidence of increased

density of riparian vegetation distribution within the creek system as a result of prolonged

release of surplus water. The change in vegetation pattern is generally confined to areas

adjacent to the discharge outlets and pools, identified as local depressions filled by discharged

water.

The increase in riparian vegetation density associated with surplus water discharge could be

exacerbated by increased creek flows and runoff at times where above average annual rainfall

were recorded, in particular during the period 1995 to 2000 and in 2006. 2006 was a cyclone

prone year with four cyclones passing through the region, between January and March,

bringing heavy downpour to the catchment. This would enhance recharge, from rainfall and

surface flows, of the superficial aquifer and would likely sustain the water level in the creek

alluvium.


Figure 7: Photo locations (illustrated as yellow triangles) along Marillana and Weeli Wolli Creeks during the

helicopter trip on 22 April 2010. M1 to M3 illustrate photo locations along Marillana Creek and WW1 to WW5

along Weeli Wolli Creek.

Figure 8 (M1): Marillana Creek adjacent to the

BHPBIO Yandi camp

Figure 9 (M2): Marillana Creek – evidence of surface

water expression on the creek bed (south western

corner) as a result of BHP discharge


Figure 10 (M3): Marillana Creek adjacent to the JSW-

C deposit

Figure 11 (WW1): Weeli Wolli Creek immediately

downstream from the JSE Discharge Outlet 6

Figure 12 (WW2): Weeli Wolli Creek at Grey’s

crossing, approximately 1 km upstream from the

confluence with Marillana Creek. This photo shows

flooding of the access road by Hope Downs 1 and JSE

discharged water.

Figure 13 (WW3): Weeli Wolli Creek/Marillana Creek

confluence – a wide floodplain of Coolibah woodlands

Figure 14 (WW4): Weeli Wolli Creek showing

progression of the wetting front

Figure 15 (WW5): Weeli Wolli Creek at the alluvial

plain


Figure 16: Comparison between 1994 and 2009 aerial imagery showing vegetation change along a section of

Marillana Creek, adjacent to the RTIO Yandicoogina JC mine.

7.2 Evapotranspiration

Little is known of the water uptake and transpiration rate of riparian vegetation in the Pilbara

but they are likely to vary with vegetation types and distribution within the creek system. High

water use (groundwater dependent) species, such as Cadjeput and River Red Gums, are likely

to transpire more than species that are adapted to drought conditions. Hydrological

measurements conducted by Peck et al (1997) on a stretch of Marillana Creek, adjacent to the

JSW deposit, revealed that evapotranspiration from the creek pools and riverine vegetation is

approximately 25 to 35 % of the rate of evaporation from a standard pan. Based on these

findings and the average annual pan evaporation 3500 mm estimated for the Yandicoogina

area, the local evapotranspiration rates would vary between 875 and 1225 mm/year. Using

Peck‟s estimations, information from available vegetation surveys and visual inspection during

the site visit on 22 April 2010, the evapotranspiration rates of vegetation commonly found in

Marillana and Weeli Wolli Creeks were estimated and summarised in Table 1.

Table 1: Estimated evapotranspiration rates of vegetation found in Marillana and Weeli Wolli Creeks

Photo location2 Main vegetation types

Evapotranspiration

(ET) rate (mm/year)

M1 – dense and well

established trees

Eucalyptus camaldulensis (River

Red Gum)

Eucalyptus victrix (Coolibah)

Melaleuca argentea (Cadjeput)

1050

M2 – dense and well

established trees with

evidence of surface water

pools


Red Gum)



1050

2 As of the locations of the photos taken during the helicopter trip on 22 April 2010, as illustrated in Figure 7


M3 – vegetation vigour

evidently declines in this

stretch of Marillana Creek


Red Gum)



700 - despite the same

vegetation types as

above, ET rate was

lowered due to decline in

vegetation vigour

WW1 – narrow riparian

vegetation corridor; larger

trees lined the banks of

Weeli Wolli Creek


Acacia citrinoviridis (Black Mulga) 600

WW2 – wide floodplain with

extensive vegetation growth



WW3 – Weeli

Wolli/Marillana Creek

confluence; wide floodplain

with extensive vegetation

growth



Red Gum)

1050

WW4 – wide floodplain with

extensive vegetation growth



WW5 – alluvial plain

supporting smaller plant

species

Mulga species

Shrublands/grasslands 530


Discharge modelling

8. Modelling approach

8.1 Defining the discharge footprint

How creeks behave and where water moves and pools when water is artificially added to a

creek system are dependent on many interconnected variables, including discharge volume,

creek bed topography, alluvial/colluvial thickness, evaporation, evapotranspiration and recent

rainfall. Thus creek behaviour will vary over time, with season, changes in weather and along

the length of the creek. This makes it difficult to map when and where changes to the system

may occur and when those changes may impact other aspects of the creek ecology.

However, two important characteristics of the artificial discharge that can be quantified for a

specified discharge rate in order to provide a basis for an assessment of the creek ecosystem

reaction are (Figure 17):

the minimum distance surface water will consistently flow along the surface of the creek

bed, where the creek bed will be constantly saturated, and

the maximum possible extent of surface water expression of any artificial discharge

downstream of the outlet (maximum surface water inundation) or “discharge footprint”,

where the creek bed may become saturated after a period of continuous discharge once

steady state conditions are established.

Figure 17: Reactions states to creek discharge.


As illustrated in the creek cross section in Figure 18, water discharged to a creek will flow

along the surface of the creek, losing water via infiltration or evaporation; until the volume of

water dissipates into the creek bed or is dammed by a small change in the creek bed

topography (see Figure 17 – initial conditions).

As the creek bed becomes saturated, there is less room (pore space) for water to infiltrate into

the creek bed. Infiltration rates will subsequently reduce as the wetting front moves through or

around creek bed materials with lower porosity, i.e. clays, calcretes and even roots. When the

volume of water flowing down the creek exceeds the volume of water removed from the creek

via storage, recharge (loss beyond the root zone), evaporation and evapotranspiration, water

will then start to flow across the creek bed again and the distance the surface water is seen to

flow down the creek increases (see Figure 17 – transient conditions).

Evaporation

Recharge

Evapotranspiration

Infiltration

alluvial

bedrock

Water balance equation:

Footprint

length (m)

= discharge volume (m3/s)

evaporation x flow top width (m) + (evapotranspiration+recharge)(m/s) x

riparian zone width (m)

Surface water

expression (m)

= discharge volume (m3/s)

evaporation (m/s) x flow top width (m) + infiltration (m/s) x wetted perimeter (m)

Figure 18: Stylised water balance cross section and equations for estimating discharge impact.

Water will also move obliquely through the creek bed, albeit at a slower rate, if the effort

required for the water to move vertically is greater than the effort to move horizontally. This

can be the case if the pore space rapidly decreases vertically, for example with buried clay

lenses, calcrete or shallow bedrock, or if there is a preferential pathway (micro-scale) of higher

porosity within the alluvial sediments, such as those generated by plant roots, sand seams or

rock fractures. This oblique water movement, also referred to as through-flow or interflow,

enables water to return to the surface as surface water flow when the depth to the buried

barrier decreases or the creek bed slope suddenly increases (break-of-slope); creating streams,

increasing stream flow and/or creating pools.

Thus the degree of creek bed saturation, and the potential for water to be seen to flow over the

creek bed, is influenced by creek bed topography and transient variations in climate, e.g. daily


evaporation rates, seasonal evapotranspiration variations, rainfall and humidity. As a result,

transient flow conditions dominate; such that the discharge may not be seen to continuously

flow over the creek bed, although water may continue to flow through it.

Eventually, given relatively static environmental and atmospheric conditions, the system

reaches equilibrium; when the volume of water entering the system is equal to the volume of

water leaving the system through evaporation, evapotranspiration and losses beyond to root

zone (recharge) (Figure 18). The length of the creek over which the discharged water is lost to

the environment for these generalised “static” environmental and atmospheric conditions is

described as the maximum3 surface water inundation or „discharge footprint‟ (see Figure 17 –

steady state conditions).

8.2 Surface water – groundwater connectivity

“In connected water resources4, the flow of water between the surface water feature and the

aquifer is called the seepage flux. The convention is that positive seepage flux indicates

upwards groundwater flow to the stream.” On a regional or creek system scale, surface water

and ground water interactions are broadly described as (after Winter et. al., 1998):

Gaining groundwater inflow (Figure 19) where seepage flux is positive. In the Pilbara

gaining creek systems are characterised by permanent to semi-permanent water features

such as pools or springs.

Losing water to the underlying aquifer (Figure 20) where seepage flux is negative,

however there is a connection (hyporheic zone) between the surface water and

groundwater systems. In the Pilbara losing creek systems are characterised by semi-

permanent pools, dense riparian vegetation, and shallow groundwater tables.

Indirectly connected (or disconnected) losing stream (Figure 21) where seepage flux is

negative with no hyporheic zone. In the Pilbara indirectly connected creek systems are

characterised by the absence of surface water features and poorly defined riparian

vegetation.

Figure 19: Schematic representation of surface water – groundwater interaction for a gaining system (after

Winter et al., 1998).

3 The minimum distance of surface water expression is differentiated from the distance of maximum surface

water inundation through the use of surface infiltration rates instead of evapotranspiration and recharge rates.

4 Sourced from http://www.connectedwater.gov.au/processes/index.html accessed 5 May 2010, defining a

connected water resource as the combination of surface water feature(s), such as a river, estuary or wetland,

and the groundwater system(s) that can directly interact in terms of movement of water.

http://www.connectedwater.gov.au/processes/index.html


Figure 20: Schematic representation of surface water – groundwater interaction for a losing system with

saturated connection (after Winter et al., 1998).

Figure 21: Schematic representation of surface water – groundwater interaction for an indirectly connected

losing system demonstrating unsaturated connection with the groundwater aquifer (after Winter et al., 1998).

Some creek systems may always gain groundwater, or alternatively always lose water to

groundwater. In most cases the water exchange direction varies significantly along a creek

and water movement can alter in very short timeframes or seasonally in response to flooding

or evapotranspiration (Winter et. al., 1998). Thus the average seepage flux condition is used to

characterise the creek system.

However, in the ephemeral creek systems of the Pilbara, the effect (or impact) of creek

discharge on a creek system is observed on a local scale. Thus it is necessary to characterise

and predict the more complex, local scale behaviour of the water movement in order to

appreciate and subsequently assess the impact of discharge within the discharge footprint.

On a local scale, water movement within a creek can be observed to:

Flow over the creek bed (surface flow);

Move in and out of creek bed and bank alluvial materials (interflow), changing the volume

of surface flow without changing the total volume5 flowing down the reach;

Mix with groundwater in the hyporheic zone, changing water chemistry6 without changing

total flow volume;

Gain volume from confined or unconfined groundwater aquifer discharge, changing water

chemistry7;

5 Total flow volume is the proportion of the original discharge plus any additional groundwater discharge

defined as the input discharge rate for the reach.

6 Applicable when groundwater chemistry is different from surface water chemistry

7 Applicable when groundwater chemistry is different from surface water chemistry


Lose volume to the atmosphere and riparian vegetation; or

Lose volume to recharge into groundwater aquifers.

Within our model it is necessary to establish whether a reach is gaining or generically losing

(losing or indirectly connected), to define the recharge rate. Converse to seepage flux,

recharge is positive when water volume is lost from the reach and negative when water is

gained, due to the mathematical equation employed. Specific gaining or losing behaviour

conditions for the reaches are subsequently established through observation of the local

catchment conditions.

However, by differentiating between surface infiltration rates from the surface water

expression equation and recharge plus evapotranspiration loss rates from the discharge

footprint equation, it is possible to determine whether total flow volume loss is limited by

surface creek bed conditions or from subsurface geological constraints.

Water movement that is limited by surface infiltration is generally associated with indirectly

connected losing reaches. The saturation footprint is generally limited to the area directly

beneath the surface flow. While this water can be accessed by riparian vegetation, unless the

flows flood the riparian vegetation the increased plant available water will result in a general

increase in vegetation vigour and recruitment.

Water movement that is limited by subsurface geological constraints is most likely to

encourage water to move in and out of the creek bed, creating transient pools and associated

saturated bank conditions within the reach. Sustained discharge into ephemeral creek reaches

with subsurface geological constraints is likely to produce the greatest degree of change in the

reach, with saturated bed and bank conditions potentially resulting in bank

degradation/collapse and decreased vegetation vigour or death in plants adverse to saturated

soil conditions.

9. Discharge water balance calculations Definitive spatial data and temporally varying climate, infiltration, evapotranspiration and soil

information is generally not available for Pilbara creek tributaries. This makes it impossible to

use two-dimensional or numerical models to accurately map catchment and creek response.

As an alternative, an empirical methodology was developed employing the simple,

conservative water balance equations from Figure 18 to estimate the length of the creek over

which the discharge is lost to the environment.

9.1 Methodology

Each branch of the creek below the discharge outlet is divided into sections or “reaches” with

similar catchment characteristics. Estimates of evaporation, evapotranspiration and

infiltration beyond the soil root zone (recharge) are then assigned to the reach based on the

catchment characteristics or information inferred from the catchment characteristics (refer to

Sections 4 to 7). A description of how the input values were determined is summarised in

Table 2.

Reach geometry inputs including the wetted perimeter (the cross section of the creek under

water) and top width (the water surface exposed to evaporation) were determined using the

Manning formula, which is an empirical formula for open channel flow. From the reach input

values the potential out flow, or loss to environment, was determined. By subtracting the

outflow from the inflow, the balance of the flows was distributed to the next downstream

reach, until no flow remained. The surface water expression estimate (Figure 18) calculates

the minimum distance downstream from the discharge outlet that will be constantly saturated.


The discharge footprint is defined as the length of creek over which all loss activities could take

place, representing the area where alluvial saturation conditions (increased available water)

will vary. For example, saturation conditions and associated pools, in between the minimum

and maximum lengths will vary with vegetation growth (season) and climate conditions.

A 19 km section of Marillana Creek was modelled from the current BHPBIO discharge location

to the catchment outlet and a 39 km section of Weeli Wolli Creek was modelled from the

existing Hope Downs 1 discharge outlet to Puggs Bore (738293 E; 7492847 N). Both creeks

were subdivided into six reaches with similar creek morphology, soil conditions and vegetation

type and patterns (Figure 22). Average reach characteristics used as input into the water

balance equation are presented in Table 3 and Table 4.

Table 2: Model simulation inputs

Input value Description

Reach geometry Channel dimensions including channel base width and bank (side) slopes,

reach length and bed slope were estimated based on 1:5000 scale spot

height and 1 m contour data, with accuracy of +/- 0.2 m horizontal and +/-

0.17 m vertical. In the most downstream section of Weeli Wolli Creek

regional 1:50,000 scale spot height data was available, suitable for 10 m

contour data only.

Manning’s roughness

coefficient n

Manning’s roughness coefficients were estimated according to the Guide

for selecting Manning’s roughness coefficients for natural channels and

floodplains, (USGS 1990) in consideration of channel irregularities,

variation in cross section, obstructions, vegetation density and

meandering of the reach.

Flow conditions The Manning formula was used to calculate the wetted perimeter, top

width, velocity, and water depth of the flow. The average reach value was

then used in the water balance equation.

Vegetation width Estimated from 1: 10,000 geological mapping, available vegetation and

flora surveys and aerial photographs, the extent of riparian vegetation

growth is averaged for each reach. The vegetation width is used to

estimate both the area of evapotranspiration and recharge as horizontal

movement of water beyond the riparian zone is considered to be minimal.

Evaporation Estimated from average annual pan evaporation for the Yandicoogina

area, 3500 mm/year (from Department of Agriculture Western Australia,

2003).

Evapotranspiration

The local evapotranspiration rate was estimated to range from 530 to

1050 mm/year based on vegetation types and density (Table 1).

Recharge rate The recharge rates represent the estimated loss of water to below the root

zone. Due to the lack of knowledge on the rate of recharge in the area,

regional estimates for the Pilbara, 1 x 10-7

m/s for clay materials and 2 x

10-7

m/s for sandy materials, were used. These estimates are used by the

Bureau of Rural Science for ‘loss’ or ‘recharge’ estimation (Raupach et al.,

2001).

However, loss of water to below the root zone does not necessarily

represent groundwater recharge. If used for groundwater recharge

estimation, these values will overestimate recharge in groundwater fed

creek systems and underestimate recharge rate over deep

alluvial/sedimentary geology.

Surface infiltration rate An estimate of the soil infiltration rate for a typical sandy to loamy Pilbara

floodplain alluvial of 10 mm/h was used for both creeks.


Figure 22: Reach locations along Marillana and Weeli Wolli Creeks


This page has been left intentionally blank.


Table 3: Reach characteristics used to model different discharge volumes at Marillana creek.

Marillana Creek – Reach 1

Reach characteristics Typical cross section Riparian vegetation corridor Summary

Reach length (m) 1,336

Low flow channel – base

width (m) 12

Riparian width (m) 140

Bed slope (m/m) 0.00257

Manning’s roughness 0.065

Infiltration rate (mm/h) 10

Recharge rate (m/s) 2 x 10-7

Evaporation (mm/year) 3500

ET (mm/year) 1050

0 50 100 150 200 250 300 350 400 450 500

Lo

w flo

w c

ha

nn

el

flo

od

pla

in

floodplain

~ 522 mRL

~ 514 mRL

~ 15 m

Marillana Creek Reach 1 starts from the current BHP discharge outlet, 500 m down

gradient from the BHP railway bridge. Water is released into a defined, relatively stable

drainage channel, with minor meandering planform and active floodplain of

approximately 140 m wide. Vegetation is well established within the reach and evenly

distributed across the floodplain. Vegetation is dominated by woodlands of Eucalyptus

camaldulensis (River Red Gum), E. victrix (Coolibah) and Melaleuca argentea

(Cadjeput).

The groundwater table has risen by approximately 8 m along this reach (the 2008

groundwater table is approximately 1 – 2 m below the creek bed), with photographic

evidence of surface water expression as a result of prolonged surplus water discharge.

It is likely that, during a flood event, the alluvium would rapidly saturate, resulting in

groundwater discharging into the creek for weeks or months until the water table

recedes to its preceding level. This reach is recognised as a losing system and

subsurface geological constraints are identified as the likely limiting factor for the

volume of water lost from the system.





width (m) 16







ET (mm/year) 1050 0 50 100 150 200 250 300 350

Lo

w flo

w c

ha

nn

el

flo

od

pla

in

floodplain

~ 518 mRL

~ 513 mRL~ 12 m

The channel within Reach 2 is more incised and braided than Reach 1 with greater

degree of meandering. While the width of the floodplain and riparian zone is slightly

wider than in Reach 1, vegetation appears to be less dense except at locations where

the CID aquifer is intersected (as highlighted in the aerial imagery). The inner section of

the reach where the CID is absent, vegetation vigour declines. Vegetation is mainly

comprised of woodlands of Eucalyptus camaldulensis (River Red Gum), E. victrix

(Coolibah) and Melaleuca argentea (Cadjeput).

The groundwater table has risen by approximately 5 m along this reach (the 2008

groundwater table is approximately 2 m below the creek bed), with photographic

evidence of surface water expression as a result of prolonged surplus water discharge.

It is likely that, during a flood event, the alluvium would rapidly saturate, resulting in

groundwater discharging into the creek for weeks or months until the water table

recedes to its preceding level. This reach is recognised as a losing system and

subsurface geological constraints are identified as the likely limiting factor for the



Reach characteristics Typical cross section (for the lower section of Reach 3) Riparian vegetation corridor



width (m) 17







ET (mm/year) 700

0 50 100 150 200 250 300 350 400 450 500

Lo

w fl

ow

ch

an

ne

l

floo

dp

lain

floodplain

~ 500 mRL

~ 506 mRL

~ 16 m

Reach 3 is characterised by a meandering creek with less defined banks, but wider and

flatter floodplain. Water will be distributed across a wider area during floods in this

reach than Reach 1 or 2, hence reduces the average flood water levels and velocities

and allows deposition of sediments along this reach. Common riparian vegetation

found in this reach includes Eucalyptus camaldulensis (River Red Gum), E. victrix

(Coolibah) and Melaleuca argentea (Cadjeput) but vegetation vigour and density

evidently decline in this reach than Reach 1 or 2.There was a 10 m difference in

groundwater table between the upper and lower section of Reach 3, as observed in

2008. This was likely attributed to the effects of drawdown resulted from groundwater

abstraction at the adjacent JC mine.

There is evidence of surface water expression and pools along the upper section of

Reach 3 while absent in the lower section, indicating the progression of the wetting front

of discharged water from the BHPBIO operation. Reach 3 is recognised as a losing

system and subsurface geological constraints are identified as the likely limiting factor

for the volume of water lost from the system.

Not to scale

Not to scale

Not to scale



Reach characteristics Typical cross section (for the section of Reach 3 where the CID

intersects the creek bed) Riparian vegetation corridor Summary


Low flow channel – base width

(m) 20







ET (mm/year) 600

496

498

500

502

504

506

508

510

0 100 200 300 400 500 600 700 800 900

Lo

w flo

w c

ha

nn

el floodplain

~ 485 mRL

~ 490 mRL

< 5m

Se

co

nd

ary

ch

an

ne

l

Reach 4 characterises a section of Marillana Creek that drains adjacent to the JC

mine. It is defined by a braided creek system with incised banks and recognisable

secondary flow channels. Creek alluvium is notably thinner in this reach.

Surplus water from the mine operations (JC and JSE) are released at several locations

along this reach producing surface flows and pools. Increased riparian vegetation

density and vigour were observed in areas adjacent to the discharge outlets and along

the fringe of surface water pools. Common vegetation includes Eucalyptus

camaldulensis (River Red Gum) and E. victrix (Coolibah).

Reach 4 is located within the cone of depression and influenced by groundwater

abstraction at the JC mine. The groundwater table at this reach is likely to fluctuate

locally depending on the abstraction rate and regime. The 2008 water table was at 485

mRL, approximately 15 m below the pre-mining water level. Reach 4 is recognised as

a losing system and subsurface geological constraints are identified as the likely

limiting factor for the volume of water lost from the system.





width (m) 32







ET (mm/year) 600

0 100 200 300 400 500

Lo

w flo

w c

ha

nn

el

floodplain floodplain

~ 489 mRL

~ 479 mRL

~ 18 m

Reach 5 is differentiated from Reach 4 by a significantly wider floodplain. During

floods water is likely to spread across the floodplain, hence reduces the flood levels

and velocities and allows deposition of sediments along this reach. However the inner

section of the reach (highlighted) is flanked north and south by outcropping Weeli Wolli

Formation, which constricts flow such that water is likely to back up during large flood

events.

Vegetation density increases slightly in this reach than Reach 4; common vegetation

includes Eucalyptus victrix (Coolibah) and Acacia citrinoviridis (Black Mulga).

The groundwater table has risen by approximately 10 m along this reach, with

photographic evidence of surface water expression as a result of prolonged surplus

water discharge. Increased vegetation density was observed along the fringe of

surface water pools. Reach 5 is recognised as a losing system and subsurface

geological constraints are identified as the likely limiting factor for the volume of water

lost from the system.





(m) 28







ET (mm/year) 1050

0 200 400 600 800 1000

~ 471 mRL

~ 485 mRL

~ 30 m

Lo

w flo

w c

ha

nn

el

Se

co

nd

ary

ch

an

ne

l

floodplain

Reach 6 illustrates the mouth of Marillana Creek. This reach is characterised by a

braided creek system within a wide floodplain that extends several hundred metres

across, with multiple, secondary active and inactive flow channels. During floods,

water is likely to distribute across the floodplain, hence reduces the flood water levels

and velocities within the reach.

Vegetation is dense within this reach and dominated by woodlands of Eucalyptus

camaldulensis (River Red Gum) and E. victrix (Coolibah). The dense vegetation assists

to increase the evapotranspiration rates and recharge by increasing plant roots uptake.

These conditions are likely to enable more discharged water to be accommodated in

the system than the channel geometry alone allows.

The groundwater table has risen by approximately 15 m along this reach. There is

evidence of surface water expression and pools along the upper section of Reach 6

while absent in the lower section, indicating the progression of the wetting front of

discharged water from the JC and JSE mine operations. Reach 6 is recognised as

originally indirectly connected now functioning as a losing system and the channel

wetted perimeter is identified as the likely limiting factor for the volume of water lost

from the system.

Not to scale

Not to scale

Not to scale


Table 4: Reach characteristics used to model different discharge volumes at Weeli Wolli Creek.

Weeli Wolli Creek – Reach 1




width (m) 22





Recharge rate (m/s)

(Weeli Wolli Spring Baseflow) -5 x 10

-8


ET (mm/year) 700

? ?

Lo

w flo

w c

ha

nn

elfloodplain floodplain

~ 30 m

Weeli Wolli Creek Reach 1 starts from the existing Hope Downs 1 discharge outlet, 10

km down gradient from the mine operation. Water flows down a relatively stable creek

with minor meandering planform and active floodplain of approximately 200 m wide.

Weeli Wolli Spring is located 500 m down gradient from the discharge outlet. The

groundwater table has intersected the sloping creek bed at the spring and groundwater

discharge is providing a base flow component to the pools located along the reach.

Reach 1 is recognised as a groundwater gaining system with Weeli Wolli Spring

discharging at a rate of approximately 4.2 ML/day.

Riparian vegetation is well established within the reach; increased vegetation density

was observed along the fringe of the permanent/semi-permanent pools. Insufficient

information was available to define the vegetation types within Weeli Wolli Creek Reach

1, but plant species are likely to associate with groundwater, such as Eucalyptus

camaldulensis (River Red Gum) and Melaleuca argentea (Cadjeput).





(m) 22







ET (mm/year) 600

Lo

w flo

w c

ha

nn

el

floodplain floodplain

~ 30 m

? ?

Reach 2 is characterised by a meandering creek with more incised banks and an active

floodplain that varies in width. There are sections along the reach (sections that are

defined by narrow floodplain), that may experience high flow velocity during floods.

Potential scouring and increased sediment loads may be experienced within these

sections. Deposition of these sediments will occur whenever flow velocities reduce.

While Reach 1 is dominated by woodlands of large tree species these trees are

generally absent in Reach 2. This vegetation pattern change may attribute to change in

water availability within the reach. Plant species in Reach 2, which may include

Eucalyptus victrix (Coolibah) and Acacia citrinoviridis (Black Mulga), are likely to source

their water requirements from the soil layer rather than groundwater.Groundwater

elevations are unknown along the reach but are expected to have risen since surplus

water discharge began in 2006 from the Hope Downs 1 operation. Reach 2 is

recognised as a indirectly connected losing system although subsurface geological

constraints are identified as the likely limiting factor for the volume of water lost from the

system.





width (m) 27







ET (mm/year) 600

Lo

w flo

w c

ha

nn

el

floodplain

~495 mRL

~475 mRL

~ 10 m

Weeli Wolli Creek Reach 3 is a relatively short reach, characterised by a stable and

straight channel with well defined banks. This reach is likely to experience high flow

velocity during floods. Potential scouring and increased sediment loads may be

expected within the reach. The riparian vegetation corridor is narrow in this reach but

larger trees were observed to line the creek banks. Common plant species include

Eucalyptus victrix (Coolibah) and Acacia citrinoviridis (Black Mulga).

The JSE reinjection borefield is located east of the creek system. Reinjection and

discharge of surplus water from the JSE mine, as well as discharge from the Hope

Downs 1 operation, have resulted in the rise of the groundwater table by approximately

20 m. It is likely that, during a flood event, the alluvium would rapidly saturate, resulting

in groundwater discharging into the creek for weeks or months until the water table

recedes to its preceding level. Reach 3 is recognised as originally indirectly connected

now functioning as a losing system and subsurface geological constraints are identified

as the likely limiting factor for the volume of water lost from the system.

Not to scale

Not to scale

Not to scale






(m) 26







ET (mm/year) 600

Lo

w flo

w c

ha

nn

el floodplain

~485 mRL

~465 mRL~ 26 m

floodplain

Reach 4 is defined by a meandering creek within a relatively narrow floodplain, but widens

towards the confluence with Marillana Creek.

The riparian vegetation corridor widens slightly in this reach than Reach 3 with larger trees,

such as Eucalyptus victrix (Coolibah) and Acacia citrinoviridis (Black Mulga) lined the banks

of the creek channel.

The groundwater table has risen by approximately 20 m along this reach, with photographic

evidence of surface water expression as a result of reinjection and surplus water discharge

from both the JSE and Hope Downs 1 mining operations. As a result it is likely that, during

a flood event, the alluvium would rapidly saturate, resulting in groundwater discharging into

the creek for weeks or months until the water table recedes to the pre-flood level. This

reach is recognised as originally indirectly connected now functioning as a losing system

and subsurface geological constraints are identified as the likely limiting factor for the






width (m) 40







ET (mm/year) 700

Lo

w flo

w c

ha

nn

el

floodplainfloodplainS

eco

nd

ary

ch

an

ne

l

~470 mRL

~455 mRL

~ 32 m

Weeli Wolli Creek Reach 5 is located immediately downstream from the Marillana Creek

intersection. The reach is characterised by a braided, meandering creek system dominated

by multiple active and inactive flow channels that are capable of changing course during a

large flood event. The floodplain stretches from 300 m at the mouth to over 800 m across

in the central section of the reach. The floodplain narrows again towards the end of Reach

5, where the channel is constrained between outcropping Weeli Wolli and Brockman Iron

Formation. This will constrict flow and cause water to back up during large flood events.

Vegetation is dense in Reach 5, dominated by woodlands of Eucalyptus victrix (Coolibah).

Groundwater level varies from 3 m at the mouth to approximately 23 m (the pre-mining

water level) at the end of the reach. Insufficient information was available to define the soil

and alluvial conditions in Reach 5 to enable characterisation of the mechanisms that

sustain the extensive vegetation growth, in particular in the central section of the reach,

where the groundwater table drops to > 15 m below ground level. The alluvials in Reach 5

may contain more clay and the presence of this clay layer may cause perching of the

watertable thus provide a water source for vegetation growth. Reach 5 is recognised as

originally indirectly connected now functioning as a losing system and subsurface

geological constraints are identified as the likely limiting factor for the volume of water lost

from the system.





(m) 37







ET (mm/year) 530

Lo

w flo

w c

ha

nn

el

floodplain

? ?

~ 30 - 40 m

Reach 6 is located within a wide, flat alluvial fan system that stretches 20 to 30 km across,

characterised by a meandering creek system that is capable of changing its course during

large flood events. Reach 6 terminates at Puggs Bore, approximately 11 km up gradient of

the BHP railway line.

Groundwater elevations are currently unknown but are likely to be deep (20 – 30 m below

ground level), hence riparian vegetation maintained within this reach is unlikely to be

groundwater reliant but sustained by water available within the unsaturated zone of the soil

layer, recharged by surface flows and rainfall infiltration. Reach 6 was observed to support

smaller plant species, including some Mulga species over open shrubland and grassland.

Reach 6 is recognised as an indirectly connected losing system and the channel wetted

perimeter is identified as the likely limiting factor for the volume of water lost from the

system.

Not to scale

Not to scale

Not to scale


10. Modelling scenarios

10.1 Existing discharge regime

The volume and rate of surplus water discharge on site is variable, depending on the mining

schedule, season, occurrences of storm and cyclonic events and rate at which site can use the

surplus water. Figure 23 illustrates the variability in surplus water discharge within the study

area from 1998 t0 2009. The total discharge, from all three mine operations (BHPBIO Yandi,

RTIO Yandicoogina and RTIO Hope Downs 1 operation), varies between 15,000 kL/day (May

2005) and 160,000 kL/day (February 2009). A steady increase in total discharge was

observed from 1998 to 2000, predominantly resulted from water released from the BHPBIO

operation, then a slow decline before a steep rise from 2006 attributed to the development and

release of surplus water from the Hope Downs 1 and JSE operations. Based on the existing

discharge regime of the sites, three scenarios were generated and modelled to assess the

existing situation and movement of water along Marillana and Weeli Wolli Creeks.

0

20000

40000

60000

80000

100000

120000

140000

160000

180000

199

8

199

9

20

00

20

01

20

02

20

03

20

04

20

05

20

06

20

07

20

08

kL/d

DO3 (kL/d) DO4 (kL/d) DO5 (kL/d) HD (kL/d) BHP (kL/d)DO1 (kL/d) DO2 (kL/d) DO6 (kL/d) DO8 (kL/d) Total (kL/d)

Figure 23: Variability in surplus water discharge within the study area from 1998 to 2009

10.1.1 Scenario 1: Comparison of observed and predicted wetting fronts

The wetting front associated with the discharge observed as a series of disconnected pools

along Weeli Wolli Creek was monitored from March 2007 to February 2009. The distance

extended downstream from the Hope Downs 1 discharge outlet was measured in October 2007

(22 km), December 2007 (23.5 km) and August 2008 (24 km). Under this scenario, the

discharge regimes associated with the measured extents were investigated to assess the

accuracy of the discharge footprint methodology:

a) 126 ML/day in October 2007

b) 125 ML/day in December 2007

c) 138 ML/day in August 2008


10.1.2 Scenario 2: Average discharge between 2007 and 2009

Figure 23 revealed that surplus water discharge within the study area peaked during the

period 2007 and 2009. The average discharge rate, 116 ML/day or 42 GL/year, between 2007

and 2009 was investigated in this scenario to assess the average maximum discharge footprint

that could be expected along the creek systems between 1998 and 2009.

10.1.3 Scenario 3: Peak discharge between 1998 and 2009

In this scenario we investigate the response of the creek systems through continual discharge

of 163 ML/day or 60 GL/year, the total peak rate recorded from the mine operations during

the period 1998 and 2009. Discharge footprint was determined based on the assumption that

steady state conditions were established.

10.2 Proposed discharge scenarios

With future expansion and development of the JSW and Oxbow deposits, the total

groundwater abstraction rate for the RTIO Yandicoogina operation may increase from 35

GL/year (currently licensed) to maximum 55 GL/year. This may increase the rate of surplus

water generated and discharged into Marillana and Weeli Wolli Creeks. Hence discharge

scenarios are used to investigate the potential changes to the creek systems resulting from

different discharge rates and varying input locations.

10.2.1 Scenario 4: Discharge rate options – 60 GL/year

Similar to Scenario 3, continual discharge of 60 GL/year is released into the creek systems.

However in order to accommodate additional surplus water that may be generated from JSW

and Oxbow, four options are modelled to investigate the response of the creek systems by

increasing the current total peak discharge by 5, 10, 15 and 20 GL/year. Hence the modelled

options in this scenario include:

a) 60 GL/year – current total peak discharge

b) 65 GL/year – current total peak discharge plus additional 5 GL/year from JSW and

Oxbow

c) 70 GL/year – current total peak discharge plus additional 10 GL/year from JSW and

Oxbow

d) 75 GL/year – current total peak discharge plus additional 15 GL/year from JSW and

Oxbow

e) 80 GL/year – current total peak discharge plus additional 20 GL/year from JSW and

Oxbow

10.2.2 Scenario 5: Discharge rate options – 90 GL/year

In this scenario we assume the worst case where all feasible options for surplus water disposal

have been exhausted and continual discharge to surface drainages becomes the remaining

option for surplus water management. Under this scenario, all abstracted groundwater, 90

GL/year (15 GL/year from BHPBIO Yandi operation, 35 GL/year from RTIO Yandicoogina

operation and 40 GL/year from Hope Downs 1 operation), plus additional 5, 10, 15 and 20

GL/year of surplus water that may be generated from JSW and Oxbow are discharged into the

creek systems.

10.2.3 Scenario 6: Relocation of Marillana Creek discharge outlets

In this scenario we investigate the option of relocating the discharge outlets along Marillana

Creek down gradient form the mine operations, with the exception of the BHPBIO outlet and

DO3 which will remain in their original locations. DO3 will be used for environmental water

provisions to sustain creek ecosystem that may be impacted by dewatering. As shown in Table


5, discharge rate options varying from 55 GL/year, the current average discharge rate from the

mine operations, to 110 GL/year8 were investigated. Surplus water from BHPBIO Yandi outlet

and RTIO Yandi DO39 are released at Reach 1 and 4, respectively, and the remaining RTIO

Yandi water is released at Reach 6 along Marillana Creek. Discharge locations along Weeli

Wolli Creek remain unchanged.

Table 5: Modelled discharge options for Scenario 6

Scenario Discharge rate (GL/year)

BHPBIO Yandi Current RTIO

Yandi

JSW + Oxbow Hope Downs 1 Total

7a - current 5 25 25 55

7b 5 30 5 30 70

7c 10 30 10 30 80

7d 15* 35* 5 35 90

7e 15* 35* 5 40* 95

7f 15* 35* 10 40* 100

7g – peak 15* 35* 15 40* 105

7h 15* 35* 20 40* 110

*Note: current licensed maximum abstraction rate

11. Modelling results

11.1 Existing discharge footprints

The estimated wetting front footprints along Marillana and Weeli Wolli Creeks under existing

discharge condition are summarised in Table 5 and are depicted in Figure 24. The water

balance results are provided in Appendix A. A comparison between the observed and

estimated footprints along Weeli Wolli Creek showed that the differences range from -2.7 % to

2.0 %. This suggested the discharge footprint methodology was able to predict the footprint

distance (steady state) with accuracy better than ±3 %.

8 Results from the current hydrogeological modelling suggests a mean groundwater abstraction rate of 10

GL/year and up to 15 GL/year maybe dewater from JSW and Oxbow. Thus the expected peak is 105 GL/year.

9 DO3 was modelled at a constant discharge rate of 2.5 GL/year, the average rate between 2000 and 2009.


Table 6: Estimated discharge footprints for Marillana and Weeli Wolli Creeks under existing discharge

conditions.

Scenarios

Marillana Creek from BHP

discharge outlet

Weeli Wolli Creek from Hope

Downs 1 discharge outlet Footprint

distance past the

confluence of

Marillana and

Weeli Wolli

Creeks (km)

Steady

state

distance

(km)

Surface

water

expression

(km)

Maximum

discharge

footprint

(km)

Steady

state

distance

(km)

Surface

water

expression

(km)

Maximum

discharge

footprint

(km)

1a: 126 ML/d

in Oct 2007

1b: 125 ML/d

in Dec 2007

1c: 138 ML/d

in Aug 2008

16.3

16.0

11.2*

16.4

16.0

11.8*

16.4

16.0

11.8*

22.4

23.2

23.3

22.2

22.8

23.0

22.4

23.2

23.3

2.7

3.4

3.6

2: 116 ML/d or

42 GL/y 16.3 16.4 16.4 22.3 22.1 22.3 2.5

3: 163 ML/d or

60 GL/y 17.4* 16.7* 17.4* 25.2 24.5 25.2 5.5

Bold: Marillana Creek footprints that did not extend beyond confluence

* Note: no flow contribution from BHPBIO, footprint distances were measured from Junction Central

Table 7: Comparison between the observed and predicted wetting front distances along Weeli Wolli Creek

downstream from the Hope Downs 1 discharge outlet.

Date Discharge

(ML/day)

Estimated

footprint

(km)

Observed

distance

(km)

Error

21/10/2007 126 22.4 22.0 2.0%

16/12/2007 125 23.2 23.5 -1.5%

06/08/2008 138 23.3 24.0 -2.7%

Model results from Table 5 suggest there were periods where discharged water would not have

historically extended the Marillana Creek catchment outlet at the confluence with Weeli Wolli

Creek; hence anecdotally no flow contribution to Weeli Wolli Creek was observed. Thus the

progression of the wetting front along Weeli Wolli Creek was likely to be attributed to water

released from the Hope Downs 1 operation and the volume discharged from DO6, which

ranged from 1 GL/year to 4 GL/year between 1998 and 2009.


Figure 24: The estimated discharge footprints for Marillana and Weeli Wolli Creeks under existing discharge

conditions.


11.2 Proposed discharge footprints

11.2.1 Scenarios 4 and 5

The footprint distances, measured downstream from the discharge locations and downstream

from the confluence of Marillana and Weeli Wolli Creeks, for the modelled discharge scenarios

4 and 5 are presented in Figure 26 and are summarised in Table 7. The water balance results

are provided in Appendix B. Under all scenarios (except Scenarios 4a, 4b and 4c) the discharge

footprint was less than the surface water expression footprint, suggesting under these

discharged water would flow along the surface of the creek bed, with occasional pools forming

in topographical depressions within the creek bed.

Table 8: Estimated discharge footprints for Marillana and Weeli Wolli Creeks for different discharge

scenarios4 and 5

Scenarios

Marillana Creek – existing

discharge locations

Weeli Wolli Creek from Hope

Downs 1 discharge outlet

Fo

otp

rin

t d

ista

nce p

ast

the c

on

flu

en

ce o

f

Mari

llan

a a

nd

Weeli W

olli C

reeks (

km

)

Ste

ady s

tate

dis

tance (

km

)

Surf

ace w

ate

r expre

ssio

n (

km

)

Maxim

um

dis

charg

e footp

rint (k

m)

Ste

ady s

tate

dis

tance (

km

)

Surf

ace w

ate

r expre

ssio

n (

km

)

Maxim

um

dis

charg

e footp

rint (k

m)

4a: 60 GL/y

4b: 65 GL/y

4c: 70 GL/y

4d: 75 GL/y

4e: 80 GL/y

17.4*

18.7*

20.0*

20.3*

20.5*

16.7*

17.7*

18.8*

21.4*

22.6*

17.4*

18.7*

20.0*

21.4*

22.6*

25.2

26.5

27.8

28.1

28.3

24.5

25.5

26.6

29.2

30.4

25.2

26.5

27.8

29.2

30.4

5.5

6.8

8.1

9.4

10.7

5a: 90 GL/y

5b: 95 GL/y

5c: 100 GL/y

5d: 105 GL/y

5e: 110 GL/y

28.0

28.2

28.5

28.8

29.0

31.0

32.1

33.1

34.3

35.4

31.0

32.1

33.1

34.3

35.4

28.6

28.9

29.2

29.4

29.7

31.6

32.8

33.8

35.0

36.1

31.6

32.8

33.8

35.0

36.1

11.9

13.0

14.1

15.2

16.3



Figure 25: Estimated discharge footprints for Marillana and Weeli Wolli Creeks for different discharge rates.


11.2.2 Scenario 6

Results for Scenario 6 are presented in Figure 26 and are summarised in Table 9 and Table 10.

The footprint distances are provided with respect to reference locations, for example

downstream from the discharge locations and downstream from the confluence of Marillana

and Weeli Wolli Creeks. The model results suggested that discharged water from BHPBIO

outlet and DO3 would not reach the proposed outlet at Marillana Creek. Hence their volumes

do not contribute to the footprint distances estimated at Weeli Wolli Creek.

Figure 26: Estimated discharge footprints for Marillana and Weeli Wolli Creeks for Scenario 6.


Table 9: Estimated footprint distances from BHPBIO discharge outlet and DO3. BHPBIO and DO3 water from the modelled options did not reach the new proposed outlet at Marillana Creek and

therefore did not contribute to the footprint distances estimated at Weeli Wolli Creek (as shown in Table 10).

Scenario Total

discharge

volume

Volume from

BHPBIO

Volume from

DO3

Footprint distances from BHPBIO discharge outlet Footprint distances from DO3

(GL/year) (GL/year) (GL/year) Steady state

distance (km)

Surface water

expression (km)

Maximum

footprint (km)

Steady state

distance (km)

Surface water

expression (km)

Maximum

footprint (km)

7a - current 55 5 2.5 4.3 4.3 4.3 2.7 1.3 2.7

7b 70 5 2.5 4.3 4.3 4.3 2.7 1.3 2.7

7c 80 10 2.5 7.9 7.5 7.9 2.7 1.3 2.7

7d to 7h 90 to 110 15 2.5 14.0 13.4 14.0 5.2 4.6 5.2

Table 10: Estimated footprint distances from Marillana Creek proposed discharge outlet and Hope Downs 1 outlet. The modelled volumes exclude BHPBIO and DO3 water.

Scenario Total

discharge

volume

Volume from

RTIO Yandi

(excluding

DO3)

Volume

from Hope

Downs 1

Footprint distances from Marillana Creek

proposed discharge outlet

Footprint distances from Hope Downs 1

discharge outlet

Footprint distance

past the confluence of

Marillana and Weeli

Wolli Creeks

(GL/year) (GL/year) (GL/year) Steady state

distance (km)

Surface water

expression (km)

Maximum

footprint

(km)

Steady state

distance (km)

Surface water

expression (km)

Maximum

footprint (km)

(km)

7a - current 55 22.5 25 9.8 8.9 9.8 26.5 25.5 26.5 6.7

7b 70 32.5 30 11.7 13.7 13.7 28.3 30.4 30.4 10.6

7c 80 37.5 30 12.0 14.9 14.9 28.6 31.6 31.6 11.8

7d 90 37.5 35 12.2 16.1 16.1 28.9 32.7 32.7 12.9

7e 95 37.5 40 12.5 17.2 17.2 29.1 33.9 33.9 14.1

7f 100 42.5 40 12.8 18.3 18.3 29.4 35.0 35.0 15.2

7g – peak 105 47.5 40 13.0 19.4 19.4 29.7 36.0 36.0 16.3

7h 110 52.5 40 13.3 20.4 20.4 29.9 37.0 37.0 17.3


Modelling indicated that the footprint distance would extend from approximately 6.7 km to

17.3 km down gradient from the Weeli Wolli – Marillana Creek confluence for modelled

volumes 55 GL/year to 110 GL/year. Under all scenarios (except Scenario 7a) the steady state

footprint was less than the surface water expression footprint, suggesting there is limited

recharge potential beneath the creek, such that discharged water is expected to flow along the

surface of the creek, with occasional pools forming in topographic depressions within the creek

bed.

Figure 27 and Figure 28 illustrate the relationships between discharge volume and maximum

footprint measured from the proposed Marillana Creek discharge outlet, Hope Downs 1

discharge outlet and from the Weeli Wolli – Marillana Creek confluence. It is likely that the

footprint distance would increase linearly with discharge.

0

5

10

15

20

25

30

35

40

45

40 50 60 70 80 90 100 110

Discharge volume (GL/year)

Max f

oo

tpri

nt

(km

)

Footprints from proposed Marillana Creek outletFootprints from proposed Marillana Creek outlet (+/- 10%)Footprints from HD1 outletFootprints from HD1 outlet (+/- 10%)

Figure 27: A plot of discharge volume versus maximum footprint measured from the proposed Marillana

Creek discharge outlet and Hope Downs 1 discharge outlet (with +/- 10 % error margin). The plot shows a

linear increase in footprint distance with discharge. Please note that volumes discharged from the BHPBIO

outlet and DO3 were not incorporated into the plot as modelling suggested the discharged water would not

reach the proposed outlet at Marillana Creek.


0

2

4

6

8

10

12

14

16

18

20

22

40 50 60 70 80 90 100 110


Max f

oo

tpri

nt

(km

)

Discharge footprints Discharge footprints (+/- 10%)

Figure 28: A plot of discharge volume versus maximum footprint measured from the Weeli Wolli – Marillana

Creek confluence (with +/- 10 % error margin). The plot shows a linear increase in footprint distance with

discharge. Please note that volumes discharged from the BHPBIO outlet and DO3 were not incorporated into

the plot as modelling suggested the discharged water would not reach the proposed outlet at Marillana Creek.


It is important to note that Weeli Wolli Creek, in particular the section that drains the alluvial

fan system, is naturally capable of changing course during large flood events. This may occur

during the mine life of the Yandicoogina operation; modifying the existing drainage flow path

of the discharged water and altering the course of the discharge footprints (Figure 29).

Figure 29: Existing and previous drainage flow paths of Weeli Wolli Creek within the alluvial plain; the creek

system is capable of changing course during large flood events.


Conclusion

Based on the existing discharge regime of the mine sites (BHPBIO Yandi, RTIO Yandicoogina

and RTIO Hope Downs 1), three discharge scenarios (Scenarios 1, 2 and 3) were generated and

modelled to assess the existing situation and movement of discharged water along Marillana

and Weeli Wolli Creeks (model results are shown in the table below). A comparison between

the observed and estimated footprints along Weeli Wolli Creek (Scenario 1) showed that the

discharge footprint methodology was able to predict the footprint distance with accuracy

better than ±3 %. Through the water balance modelling it was determined that between 1998

and 2009 the average maximum discharge footprint along Weeli Wolli Creek, for modelled

volume 42 GL/year (Scenario 2), would extend approximately 2.5 km downstream from the

confluence with Marillana Creek. On the other hand, continual discharge of the current total

peak rate 60 GL/year (Scenario 3) into the creek systems would result in the discharge

footprint extending approximately 5.5 km down gradient from the Weeli Wolli – Marillana

Creek confluence.

Based on the model results of Scenarios 1, 2 and 3, it was determined that historically

discharged water would unlikely have extended past the Marillana Creek catchment outlet at

the confluence with Weeli Wolli Creek; hence anecdotally no flow contribution to Weeli Wolli

would have been observed. Thus progression of wetting front as observed along Weeli Wolli

Creek would primarily attribute to discharged water from Hope Downs 1 operation.

Future expansion of the RTIO Yandicoogina operation may increase the total groundwater

abstraction for the mine, with the potential to increase the volume of surplus water generated

and discharged into Marillana and Weeli Wolli Creeks. Three discharge scenarios (Scenarios

4, 5 and 6) were modelled to determine the potential changes to the creek systems resulting

from different discharge rates and varying input locations. Modelling indicated (results shown

in the table below) the footprint distance would extend from approximately 5.5 km to 16.3 km

down gradient from the Weeli Wolli – Marillana Creek confluence for modelled volumes

60 GL/year to 110 GL/year, the maximum volume modelled. Under all scenarios, with the

exception of Scenarios 4a, 4b and 4c, the steady state footprint was less than the surface water

expression footprint, suggesting there is limited recharge potential beneath the creek, such

that water discharged into the creek systems is expected to be seen to flow across the surface of

the creek bed, with occasional pools forming in topographical depressions within the creek

bed.

Upon relocating the discharge location in Marillana Creek down gradient from the mine

operations, modelling indicated discharged water from BHPBIO outlet and DO3 would not

reach the proposed outlet at Marillana Creek. Hence progression of wetting front as estimated

at Weeli Wolli Creek would be attributed to discharged water from RTIO Yandicoogina

operation at the new outlet location and from Hope Downs 1 operation. Modelling indicated

that the footprint distance would extend from approximately 6.7 km to 17.3 km down gradient

from the Weeli Wolli – Marillana Creek confluence for modelled volumes 55 GL/year to 110

GL/year. It is likely that the footprint distance would increase linearly with discharge.

Weeli Wolli Creek, in particular the section that drain the alluvial fan system, is naturally

capable of changing course during large flood events. This type of event would modify the


existing drainage flow path of the discharged water and alter the course of the discharge

footprints.

Scenarios

Discharge footprint distance (km)

Footprint distance

past the confluence

of Marillana and

Weeli Wolli Creeks

(km) Marillana Creek –

existing discharge

locations

Weeli Wolli Creek – Hope


1a: 126 ML/d in Oct

2007

1b: 125 ML/d in Dec

2007

1c: 138 ML/d in Aug

2008

16.4

16.0

11.8*

22.4

23.2

23.3

2.7

3.4

3.6

2: 42 GL/y average

discharge 2007-2009 16.4 22.3 2.5

3: 60 GL/y Peak

discharge 1998 - 2009 17.4* 25.2 5.5

4a: 60 GL/y

4b: 65 GL/y

4c: 70 GL/y

4d: 75 GL/y

4e: 80 GL/y

17.4*

18.7*

20.0*

21.4*

22.6*

25.2

26.5

27.8

29.2

30.4

5.5

6.8

8.1

9.4

10.7

5a: 90 GL/y

5b: 95 GL/y

5c: 100 GL/y

5d: 105 GL/y

5e: 110 GL/y

31.0

32.1

33.1

34.3

35.4

31.6

32.8

33.8

35.0

36.1

11.9

13.0

14.1

15.2

16.3

Scenario 6

Discharge footprint distance (km) Footprint distance

past the confluence

of Marillana and

Weeli Wolli Creeks

(km) Marillana Creek –

proposed discharge

location

Weeli Wolli Creek – Hope


a: 55 GL/y

b: 70 GL/y

c: 80 GL/y

d: 90 GL/y

b: 95 GL/y

c: 100 GL/y

d: 105 GL/y

e: 110 GL/y

9.8

13.7

14.9

16.1

17.2

18.3

19.4

20.4

26.5

30.4

31.6

32.7

33.9

35.0

36.0

37.0

6.7

10.6

11.8

12.9

14.1

15.2

16.3

17.3

Bold: Marillana Creek footprints that did not extend beyond confluence



Appendix A – Base case output


REACH 1 Yandi discharge - Marillana Reach 1 (BHP discharge)

PHYSICAL CREEK CHARACTERISTICS Riparian zone = 1, No riparian = 0 1

Stream Alluvials Rates m/s

width per

m/s

reach total

m3/s

Base width HECRAS INPUT Riparian veg width (m) 140 Infiltration (mm/h) 10 2.78E-06

Side slopes (1: x) HECRAS INPUT channel length (m) 1336 Evaporation (mm/y) 3500 1.11E-07

Mannings No, n HECRAS INPUT channel depth (m) 18 ET (m/s) ET = 30% evap 3.E-08 5.E-06 6.E-03 1050mm/year

Slope, Sf HECRAS INPUT porosity 0.2 loss past roots (m/s) 2.E-07 3.E-05 4.E-02

Time to saturate alluvials (days) 75

Water Balance

FLOW CONDITIONS Data from HECRAS averages Surfacxe water Groundwater Evaporation loss Infiltration loss SW footprint loss ET loss Past root zone lossGroundwater loss

Scenarios name

Reach

volume GL/y

Reach peak

volume

(GL/d)

Reach peak

m3/s

Ave Velocity

(m/s)

Ave Flow

Area (m2)

Ave Top

Width (m) Froude no

Ave Water

Depth (m)

Wetted

Perimeter

distance to

zero volume

(m)

loss m3 per

second

time peak

volume to

zero (s)

distance to

zero volume

(m)

Surface

water

footprint

Riparian

recharge

influence

steady state

distance (m)

Steady

state

footprint

width per

m/s total m3/s

width per

m/s total m3/s

width per

m/s total m3/s total m3/s total m3/s

width per

m/s total m3/s

SW

footprint

loss per

year per

Groundwat

er loss per

year per

reach (GL)

Limited

loss to

next

reach

Potential

for

ponding

1 Peak max (90 GL/a) 15.00 0.0411 0.476 0.18 2.925 27.000 0.15 0.150 27.003 6097.65 1.38E-05 34405.95 6,098 saturation 140.00 13,339 saturation 3.00E-06 4.00E-03 7.50E-05 1.00E-01 7.80E-05 1.04E-01 6.23E-03 3.74E-02 3.57E-05 4.76E-02 3.29 1.50 0.04765 TRUE

2 Feb 2009 (59.59 GL/a) 4.10 0.0112 0.130 0.12 1.085 19.000 0.14 0.070 19.001 2366.52 6.35E-06 20462.57 2,367 saturation 140.00 3,736 saturation 2.11E-06 2.82E-03 5.28E-05 7.05E-02 5.49E-05 7.33E-02 6.23E-03 3.74E-02 3.48E-05 4.65E-02 2.31 1.47 0.04646 TRUE

3 ave vol 07-09 (42.4 GL/a) 6.19 0.0170 0.196 0.13 1.485 21.000 0.14 0.090 21.002 3234.08 8.09E-06 24250.31 3,234 saturation 140.00 5,607 saturation 2.33E-06 3.11E-03 5.83E-05 7.80E-02 6.07E-05 8.11E-02 6.23E-03 3.74E-02 3.50E-05 4.68E-02 2.56 1.47 0.04676 TRUE

4 31/10/2007 (46.1 GL/a) 12.65 0.0346 0.401 0.16 2.405 25.000 0.14 0.130 25.003 5552.53 1.18E-05 33911.82 5,553 saturation 140.00 11,317 saturation 2.77E-06 3.71E-03 6.95E-05 9.28E-02 7.22E-05 9.65E-02 6.23E-03 3.74E-02 3.54E-05 4.74E-02 3.04 1.49 0.04735 TRUE



7 Feb 2009 (59.59 GL/a) + 5GL/a JSW 4.10 0.0112 0.130 0.12 1.085 19.000 0.14 0.070 19.001 2366.52 6.35E-06 20462.57 2,367 saturation 140.00 3,736 saturation 2.11E-06 2.82E-03 5.28E-05 7.05E-02 5.49E-05 7.33E-02 6.23E-03 3.74E-02 3.48E-05 4.65E-02 2.31 1.47 0.04646 TRUE

8 Feb 2009 (59.59 GL/a) +10GL/a JSW 4.10 0.0112 0.130 0.12 1.085 19.000 0.14 0.070 19.001 2366.52 6.35E-06 20462.57 2,367 saturation 140.00 3,736 saturation 2.11E-06 2.82E-03 5.28E-05 7.05E-02 5.49E-05 7.33E-02 6.23E-03 3.74E-02 3.48E-05 4.65E-02 2.31 1.47 0.04646 TRUE



REACH 2 Yandi discharge - Marillana Reach 2



wdith per

m/s

reach total

m3/s






Water Balance


Scenarios name

Reach

volume GL/y

Reach peak

volume

(GL/d)

Reach peak

m3/s

Ave Velocity

(m/s)

Ave Flow

Area (m2)

Ave Top

Width (m) Froude no

Ave Water

Depth (m)

Wetted

Perimeter

distance to

zero volume

(m)

loss m3 per

second

time peak

volume to

zero (s)

distance to

zero volume

(m)

Surface

water

footprint

Riparian

recharge

influence

steady state

distance (m)

Steady

state

footprint

width per

m/s total m3/s

width per

m/s total m3/s

width per


width per

m/s total m3/s

SW footprint

loss per year

per reach

(GL)

Groundwater

loss per year

per reach

(GL)

Limited loss

to next reach

(m3/s)

Potential for

ponding


2 Feb 2009 (59.59 GL/a) 2.63 0.0072 0.083 0.09 0.925 21.000 0.13 0.050 21.001 1375.32 5.32E-06 15678.71 1,375 2,712 150.00 2,235 3,572 2.33E-06 3.21E-03 5.83E-05 8.02E-02 6.07E-05 8.34E-02 1.12E-02 6.71E-02 3.73E-05 8.14E-02 2.63 2.57 0.08143184 TRUE

3 ave vol 07-09 (42.4 GL/a) 4.71 0.0129 0.149 0.11 1.365 23.000 0.13 0.070 23.001 2249.20 7.11E-06 21019.21 2,249 3,585 150.00 3,980 saturation 2.55E-06 5.74E-03 6.39E-05 1.44E-01 6.64E-05 1.49E-01 1.33E-02 7.98E-02 3.75E-05 9.88E-02 4.71 3.12 0.09881992 TRUE



6 31/08/2008 (50.5 GL/a) 1.76 0.005 0.056 0.09 0.925 21.000 0.13 0.050 21.001 919.37 5.32E-06 10480.82 919 2,256 150.00 1,494 2,831 2.33E-06 2.14E-03 5.83E-05 5.36E-02 6.07E-05 5.58E-02 7.46E-03 4.48E-02 3.73E-05 5.44E-02 1.76 1.72 0.05443514 TRUE

7 Feb 2009 (59.59 GL/a) + 5GL/a JSW 2.63 0.007 0.083 0.09 0.925 21.000 0.13 0.050 21.001 1375.32 5.32E-06 15678.71 1,375 2,712 150.00 2,235 3,572 2.33E-06 3.21E-03 5.83E-05 8.02E-02 6.07E-05 8.34E-02 1.12E-02 6.71E-02 3.73E-05 8.14E-02 2.63 2.57 0.08143184 TRUE

8 Feb 2009 (59.59 GL/a) +10GL/a JSW 2.63 0.007 0.083 0.09 0.925 21.000 0.13 0.050 21.001 1375.32 5.32E-06 15678.71 1,375 2,712 150.00 2,235 3,572 2.33E-06 3.21E-03 5.83E-05 8.02E-02 6.07E-05 8.34E-02 1.12E-02 6.71E-02 3.73E-05 8.14E-02 2.63 2.57 0.08143184 TRUE






wdith per

m/s

reach total

m3/s






Water Balance


Scenarios name

Reach

volume GL/y

Reach peak

volume

(GL/d)

Reach peak

m3/s

Ave Velocity

(m/s)

Ave Flow

Area (m2)

Ave Top

Width (m) Froude no

Ave Water

Depth (m)

Wetted

Perimeter

distance to

zero volume

(m)

loss m3 per

second

time peak

volume to

zero (s)

distance to

zero volume

(m)

Surface

water

footprint

Riparian

recharge

influence

steady state

distance (m)

Steady

state

footprint

width per

m/s total m3/s

width per

m/s total m3/s

width per


width per

m/s total m3/s

SW footprint

loss per year

per reach

(GL)

Groundwater

loss per year

per reach

(GL)

Limited loss

to next reach

(m3/s)

Potential for

ponding


2 Feb 2009 (59.59 GL/a) 0.06 0.0002 0.002 reach dry #DIV/0! #VALUE! #VALUE! #VALUE! #VALUE! 200.00 45 4,041 0.00E+00 #VALUE! 0.00E+00 #VALUE! 0.00E+00 #VALUE! 2.00E-04 1.80E-03 4.44E-05 #VALUE! #VALUE! #VALUE! #VALUE! #VALUE!

3 ave vol 07-09 (42.4 GL/a) 1.60 0.0044 0.051 0.10 0.551 19.700 0.19 0.030 19.701 889.63 5.79E-06 8747.60 890 4,886 200.00 1,086 5,082 2.19E-06 1.95E-03 5.47E-05 4.87E-02 5.69E-05 5.06E-02 4.82E-03 4.34E-02 4.66E-05 5.02E-02 1.60 1.58 0.05020019 TRUE


5 31/12/2007 (45.6 GL/a) 2.79 0.0076 0.088 0.14 0.963 21.500 0.20 0.050 21.501 1422.02 8.65E-06 10212.75 1,422 5,418 200.00 1,886 5,882 2.39E-06 3.39E-03 5.97E-05 8.49E-02 6.21E-05 8.83E-02 8.37E-03 7.54E-02 4.68E-05 8.72E-02 2.79 2.75 0.08721597 TRUE

6 31/08/2008 (50.5 GL/a) 0.04 0.0001 0.001 reach dry #DIV/0! #VALUE! #VALUE! #VALUE! #VALUE! 200.00 30 4,026 0.00E+00 #VALUE! 0.00E+00 #VALUE! 0.00E+00 #VALUE! 1.34E-04 1.21E-03 4.44E-05 #VALUE! #VALUE! #VALUE! #VALUE! #VALUE!

7 Feb 2009 (59.59 GL/a) + 5GL/a JSW 0.06 0.0002 0.002 reach dry #DIV/0! #VALUE! #VALUE! #VALUE! #VALUE! 200.00 45 4,041 0.00E+00 #VALUE! 0.00E+00 #VALUE! 0.00E+00 #VALUE! 2.00E-04 1.80E-03 4.44E-05 #VALUE! #VALUE! #VALUE! #VALUE! #VALUE!

8 Feb 2009 (59.59 GL/a) +10GL/a JSW 0.06 0.0002 0.002 reach dry #DIV/0! #VALUE! #VALUE! #VALUE! #VALUE! 200.00 45 4,041 0.00E+00 #VALUE! 0.00E+00 #VALUE! 0.00E+00 #VALUE! 2.00E-04 1.80E-03 4.44E-05 #VALUE! #VALUE! #VALUE! #VALUE! #VALUE!




REACH 1 Yandi discharge - Marillana Reach 4 (DO3, DO8, DO1/4 and DO5)



width per

m/s

reach total

m3/s






Water Balance


Scenarios name

Reach

volume GL/y

Reach peak

volume

(GL/d)

Reach peak

m3/s

Ave Velocity

(m/s)

Ave Flow

Area (m2)

Ave Top

Width (m) Froude no

Ave Water

Depth (m)

Wetted

Perimeter

distance to

zero volume

(m)

loss m3 per

second

time peak

volume to

zero (s)

distance to

zero volume

(m)

Surface

water

footprint

Riparian

recharge

influence

steady state

distance (m)

Steady

state

footprint

width per

m/s total m3/s

width per

m/s total m3/s

width per


width per

m/s total m3/s

SW

footprint

loss per

year per

Groundwat

er loss per

year per

reach (GL)

Limited

loss to

next

reach

Potential

for

ponding











REACH 1 Yandi discharge - Marillana Reach 5 (DO2)



width per

m/s

reach total

m3/s






Water Balance


Scenarios name

Reach

volume GL/y

Reach peak

volume

(GL/d)

Reach peak

m3/s

Ave Velocity

(m/s)

Ave Flow

Area (m2)

Ave Top

Width (m) Froude no

Ave Water

Depth (m)

Wetted

Perimeter

distance to

zero volume

(m)

loss m3 per

second

time peak

volume to

zero (s)

distance to

zero volume

(m)

Surface

water

footprint

Riparian

recharge

influence

steady state

distance (m)

Steady

state

footprint

width per

m/s total m3/s

width per

m/s total m3/s

width per


width per

m/s total m3/s

SW

footprint

loss per

year per

Groundwat

er loss per

year per

reach (GL)

Limited

loss to

next

reach

Potential

for

ponding




4 31/10/2007 (46.1 GL/a) 8.68 0.0238 0.275 0.14 2.017 35.240 0.18 0.060 35.242 2702.38 1.39E-05 19740.22 2,702 15,000 280.00 4,216 saturation 3.91E-06 1.06E-02 9.79E-05 2.65E-01 1.02E-04 2.75E-01 1.96E-02 2.05E-01 6.53E-05 2.35E-01 8.68 7.42 0.23533 TRUE










wdith per

m/s

reach total

m3/s






Water Balance


Scenarios name

Reach

volume GL/y

Reach peak

volume

(GL/d)

Reach peak

m3/s

Ave Velocity

(m/s)

Ave Flow

Area (m2)

Ave Top

Width (m) Froude no

Ave Water

Depth (m)

Wetted

Perimeter

distance to

zero volume

(m)

loss m3 per

second

time peak

volume to

zero (s)

distance to

zero volume

(m)

Surface

water

footprint

Riparian

recharge

influence

steady state

distance (m)

Steady

state

footprint

width per

m/s total m3/s

width per

m/s total m3/s

width per


width per

m/s total m3/s

SW footprint

loss per year

per reach

(GL)

Groundwater

loss per year

per reach

(GL)

Limited loss

to next reach

(m3/s)

Potential for

ponding

1 Peak max (90 GL/a) 24.67 0.0676 0.782 0.21 4.096 35.025 0.19 0.130 35.025 7730.69 2.14E-05 36597.17 7,731 saturation 460.00 7,034 saturation 3.89E-06 1.21E-02 9.73E-05 3.02E-01 1.01E-04 3.14E-01 4.76E-02 2.86E-01 1.11E-04 3.45E-01 9.91 10.89 0.31421449 FALSE

2 Feb 2009 (59.59 GL/a) 15.38 0.0421 0.488 0.18 3.070 33.400 0.18 0.100 33.404 5055.17 1.74E-05 28102.59 5,055 saturation 460.00 4,394 saturation 3.71E-06 1.15E-02 9.28E-05 2.88E-01 9.65E-05 3.00E-01 4.76E-02 2.86E-01 1.11E-04 3.45E-01 9.45 10.87 0.29966985 FALSE

3 ave vol 07-09 (42.4 GL/a) 1.28 0.0035 0.041 0.12 1.468 30.700 0.17 0.050 30.702 456.93 1.03E-05 3927.80 457 16,418 460.00 366 16,327 3.41E-06 1.56E-03 8.53E-05 3.90E-02 8.87E-05 4.05E-02 5.61E-03 3.37E-02 1.11E-04 4.08E-02 1.28 1.29 0.04052534 FALSE

4 31/10/2007 (46.1 GL/a) 1.25 0.003 0.040 0.12 1.468 30.700 0.17 0.050 30.702 448.57 1.03E-05 3855.94 449 16,410 460.00 359 16,321 3.41E-06 1.53E-03 8.53E-05 3.83E-02 8.87E-05 3.98E-02 5.50E-03 3.31E-02 1.11E-04 4.01E-02 1.25 1.26 0.03978397 FALSE

5 31/12/2007 (45.6 GL/a) 0.16 0.000 0.005 0.04 0.283 28.540 0.13 0.010 28.540 62.17 3.36E-06 1526.01 62 16,023 460.00 46 16,008 3.17E-06 1.97E-04 7.93E-05 4.93E-03 8.24E-05 5.13E-03 7.11E-04 4.27E-03 1.10E-04 5.18E-03 0.16 0.16 0.00512547 FALSE

6 31/08/2008 (50.5 GL/a) 8.33 0.023 0.264 0.12 1.468 30.700 0.17 0.050 30.702 2978.52 1.03E-05 25603.44 2,979 18,940 460.00 2,386 18,347 3.41E-06 1.01E-02 8.53E-05 2.54E-01 8.87E-05 2.64E-01 3.65E-02 2.19E-01 1.11E-04 2.66E-01 8.33 8.39 0.26416542 FALSE

7 Feb 2009 (59.59 GL/a) + 5GL/a JSW 20.38 0.056 0.646 0.20 3.749 34.484 0.19 0.120 34.484 6486.08 2.00E-05 32238.61 6,486 saturation 460.00 5,813 saturation 3.83E-06 1.19E-02 9.58E-05 2.97E-01 9.96E-05 3.09E-01 4.76E-02 2.86E-01 1.11E-04 3.45E-01 9.76 10.88 0.30936651 FALSE

8 Feb 2009 (59.59 GL/a) +10GL/a JSW 25.37 0.070 0.804 0.21 4.096 35.025 0.19 0.130 35.025 7950.86 2.14E-05 37639.46 7,951 saturation 460.00 7,234 saturation 3.89E-06 1.21E-02 9.73E-05 3.02E-01 1.01E-04 3.14E-01 4.76E-02 2.86E-01 1.11E-04 3.45E-01 9.91 10.89 0.31421449 FALSE




REACH 1 HD1 discharge - Weeli Wolli Reach 1



width per

m/s

reach total

m3/s




Slope, Sf HECRAS INPUT porosity 0.2 loss past roots (m/s) -5.E-08 -1.E-05 -5.E-02

Time to saturate alluvials (days) 125 Weeli Wolli Spring Baseflow 4.2 ML/day

Water Balance


Scenarios name

Reach

volume GL/y

Reach peak

volume

(GL/d)

Reach peak

m3/s

Ave Velocity

(m/s)

Ave Flow

Area (m2)

Ave Top

Width (m) Froude no

Ave Water

Depth (m)

Wetted

Perimeter

distance to

zero volume

(m)

loss m3 per

second

time peak

volume to

zero (s)

distance to

zero volume

(m)

Surface

water

footprint

Riparian

recharge

influence

steady state

distance (m)

Steady

state

footprint

width per

m/s total m3/s

width per

m/s total m3/s

width per


width per

m/s total m3/s

SW

footprint

loss per

year per

Groundwat

er loss per

year per

reach (GL)

Limited

loss to

next

reach

Potential

for

ponding

1 Peak max (90 GL/a) 40.00 0.110 1.268 0.13 25.000 25.000 17563.12 9.39E-06 135100.90 17,563 saturation 200.00 175,824 saturation 2.77E-06 1.25E-02 6.94E-05 3.13E-01 7.22E-05 3.25E-01 2.00E-02 -4.86E-02 -3.59E-06 -1.61E-02 10.25 -0.51 -0.0161 TRUE

2 Feb 2009 (59.59 GL/a) 27.77 0.076 0.880 0.13 25.000 25.000 12191.26 9.39E-06 93778.94 12,191 saturation 200.00 122,047 saturation 2.77E-06 1.25E-02 6.94E-05 3.13E-01 7.22E-05 3.25E-01 2.00E-02 -4.86E-02 -3.59E-06 -1.61E-02 10.25 -0.51 -0.0161 TRUE

3 ave vol 07-09 (42.4 GL/a) 21.25 0.058 0.674 0.13 25.000 25.000 9328.94 9.39E-06 71761.07 9,329 saturation 200.00 93,392 saturation 2.77E-06 1.25E-02 6.94E-05 3.13E-01 7.22E-05 3.25E-01 2.00E-02 -4.86E-02 -3.59E-06 -1.61E-02 10.25 -0.51 -0.0161 TRUE

4 31/10/2007 (46.1 GL/a) 19.62 0.054 0.622 0.13 25.000 25.000 8616.14 9.39E-06 66277.98 8,616 saturation 200.00 86,256 saturation 2.77E-06 1.25E-02 6.94E-05 3.13E-01 7.22E-05 3.25E-01 2.00E-02 -4.86E-02 -3.59E-06 -1.61E-02 10.25 -0.51 -0.0161 TRUE



7 Feb 2009 (59.59 GL/a) + 5GL/a JSW 27.77 0.076 0.880 0.13 25.000 25.000 12191.26 9.39E-06 93778.94 12,191 saturation 200.00 122,047 saturation 2.77E-06 1.25E-02 6.94E-05 3.13E-01 7.22E-05 3.25E-01 2.00E-02 -4.86E-02 -3.59E-06 -1.61E-02 10.25 -0.51 -0.0161 TRUE

8 Feb 2009 (59.59 GL/a) +10GL/a JSW 27.77 0.076 0.880 0.13 25.000 25.000 12191.26 9.39E-06 93778.94 12,191 saturation 200.00 122,047 saturation 2.77E-06 1.25E-02 6.94E-05 3.13E-01 7.22E-05 3.25E-01 2.00E-02 -4.86E-02 -3.59E-06 -1.61E-02 10.25 -0.51 -0.0161 TRUE






wdith per

m/s

reach total

m3/s



Mannings No, n HECRAS INPUT channel depth (m) 30 ET (m/s) ET = 20% evap 2.2.E-08 3.E-06 3.E-02 700mm/year



Water Balance


Scenarios name

Reach

volume GL/y

Reach peak

volume

(GL/d)

Reach peak

m3/s

Ave Velocity

(m/s)

Ave Flow

Area (m2)

Ave Top

Width (m) Froude no

Ave Water

Depth (m)

Wetted

Perimeter

distance to

zero volume

(m)

loss m3 per

second

time peak

volume to

zero (s)

distance to

zero volume

(m)

Surface

water

footprint

Riparian

recharge

influence

steady state

distance (m)

Steady

state

footprint

width per

m/s total m3/s

width per

m/s total m3/s

width per


width per

m/s total m3/s

SW footprint

loss per year

per reach

(GL)

Groundwater

loss per year

per reach

(GL)

Limited loss

to next reach

(m3/s)

Potential for

ponding

1 Peak max (90 GL/a) 40.51 0.1110 1.285 0.13 25.000 25.000 17786.72 9.39E-06 136820.91 17,787 saturation 150.00 35,579 saturation 2.77E-06 2.29E-02 6.94E-05 5.74E-01 7.22E-05 5.97E-01 2.75E-02 2.48E-01 3.61E-05 2.99E-01 18.83 9.42 0.2985812 TRUE

2 Feb 2009 (59.59 GL/a) 28.27 0.0775 0.897 0.13 25.000 25.000 12414.86 9.39E-06 95498.94 12,415 saturation 150.00 24,833 saturation 2.77E-06 2.29E-02 6.94E-05 5.74E-01 7.22E-05 5.97E-01 2.75E-02 2.48E-01 3.61E-05 2.99E-01 18.83 9.42 0.2985812 TRUE

3 ave vol 07-09 (42.4 GL/a) 21.76 0.0596 0.690 0.13 25.000 25.000 9552.54 9.39E-06 73481.07 9,553 saturation 150.00 19,108 saturation 2.77E-06 2.29E-02 6.94E-05 5.74E-01 7.22E-05 5.97E-01 2.75E-02 2.48E-01 3.61E-05 2.99E-01 18.83 9.42 0.2985812 TRUE

4 31/10/2007 (46.1 GL/a) 20.13 0.0552 0.638 0.13 25.000 25.000 8839.74 9.39E-06 67997.98 8,840 saturation 150.00 17,682 saturation 2.77E-06 2.29E-02 6.94E-05 5.74E-01 7.22E-05 5.97E-01 2.75E-02 2.48E-01 3.61E-05 2.99E-01 18.83 9.42 0.2985812 TRUE



7 Feb 2009 (59.59 GL/a) + 5GL/a JSW 28.27 0.0775 0.897 0.13 25.000 25.000 12414.86 9.39E-06 95498.94 12,415 saturation 150.00 24,833 saturation 2.77E-06 2.29E-02 6.94E-05 5.74E-01 7.22E-05 5.97E-01 2.75E-02 2.48E-01 3.61E-05 2.99E-01 18.83 9.42 0.2985812 TRUE

8 Feb 2009 (59.59 GL/a) +10GL/a JSW 28.27 0.0775 0.897 0.13 25.000 25.000 12414.86 9.39E-06 95498.94 12,415 saturation 150.00 24,833 saturation 2.77E-06 2.29E-02 6.94E-05 5.74E-01 7.22E-05 5.97E-01 2.75E-02 2.48E-01 3.61E-05 2.99E-01 18.83 9.42 0.2985812 TRUE



REACH 1 HD1 + Yandi discharge - Weeli Wolli Reach 3 (DO6)



width per

m/s

reach total

m3/s






Water Balance


Scenarios name

Reach

volume GL/y

Reach peak

volume

(GL/d)

Reach peak

m3/s

Ave Velocity

(m/s)

Ave Flow

Area (m2)

Ave Top

Width (m) Froude no

Ave Water

Depth (m)

Wetted

Perimeter

distance to

zero volume

(m)

loss m3 per

second

time peak

volume to

zero (s)

distance to

zero volume

(m)

Surface

water

footprint

Riparian

recharge

influence

steady state

distance (m)

Steady

state

footprint

width per

m/s total m3/s

width per

m/s total m3/s

width per


width per

m/s total m3/s

SW

footprint

loss per

year per

Groundwat

er loss per

year per

reach (GL)

Limited

loss to

next

reach

Potential

for

ponding












REACH 2 HD1 + Yandi discharge - Weeli Wolli Reach 4



wdith per

m/s

reach total

m3/s






Water Balance


Scenarios name

Reach

volume GL/y

Reach peak

volume

(GL/d)

Reach peak

m3/s

Ave Velocity

(m/s)

Ave Flow

Area (m2)

Ave Top

Width (m) Froude no

Ave Water

Depth (m)

Wetted

Perimeter

distance to

zero volume

(m)

loss m3 per

second

time peak

volume to

zero (s)

distance to

zero volume

(m)

Surface

water

footprint

Riparian

recharge

influence

steady state

distance (m)

Steady

state

footprint

width per

m/s total m3/s

width per

m/s total m3/s

width per


width per

m/s total m3/s

SW footprint

loss per year

per reach

(GL)

Groundwater

loss per year

per reach

(GL)

Limited loss

to next reach

(m3/s)

Potential for

ponding














width per

m/s

reach total

m3/s






Water Balance


Scenarios name

Reach

volume GL/y

Reach peak

volume

(GL/d)

Reach peak

m3/s

Ave Velocity

(m/s)

Ave Flow

Area (m2)

Ave Top

Width (m) Froude no

Ave Water

Depth (m)

Wetted

Perimeter

distance to

zero volume

(m)

loss m3 per

second

time peak

volume to

zero (s)

distance to

zero volume

(m)

Surface

water

footprint

Riparian

recharge

influence

steady state

distance (m)

Steady

state

footprint

width per

m/s total m3/s

width per

m/s total m3/s

width per


width per

m/s total m3/s

SW

footprint

loss per

year per

Groundwat

er loss per

year per

reach (GL)

Limited

loss to

next

reach

Potential

for

ponding

1 Peak max (90 GL/a) 44.80 0.1227 1.421 0.23 6.788 50.500 0.19 0.150 50.504 9737.63 3.33E-05 42655.69 9,738 saturation 500.00 12,173 saturation 5.60E-06 4.52E-02 1.40E-04 1.13E+00 1.46E-04 1.18E+00 8.96E-02 8.07E-01 1.17E-04 9.42E-01 37.13 29.70 0.94173 TRUE

2 Feb 2009 (59.59 GL/a) 20.18 0.0553 0.640 0.18 4.350 47.003 0.18 0.100 47.000 4713.26 2.42E-05 26476.27 4,713 16,655 500.00 5,502 17,443 5.22E-06 2.46E-02 1.31E-04 6.15E-01 1.36E-04 6.40E-01 6.11E-02 5.50E-01 1.16E-04 6.36E-01 20.18 20.05 0.63582 TRUE

3 ave vol 07-09 (42.4 GL/a) 9.30 0.0255 0.295 0.13 2.526 44.200 0.17 0.060 44.202 2310.30 1.65E-05 17897.12 2,310 22,050 500.00 2,543 22,283 4.91E-06 1.13E-02 1.23E-04 2.84E-01 1.28E-04 2.95E-01 2.82E-02 2.54E-01 1.16E-04 2.94E-01 9.30 9.27 0.29386 TRUE




7 Feb 2009 (59.59 GL/a) + 5GL/a JSW 24.87 0.0681 0.789 0.18 4.350 47.003 0.18 0.100 47.000 5807.97 2.42E-05 32625.69 5,808 17,749 500.00 6,780 18,721 5.22E-06 3.03E-02 1.31E-04 7.58E-01 1.36E-04 7.89E-01 7.52E-02 6.78E-01 1.16E-04 7.83E-01 24.87 24.71 0.78349 TRUE

8 Feb 2009 (59.59 GL/a) +10GL/a JSW 29.71 0.0814 0.942 0.19 4.824 47.703 0.18 0.110 47.703 6836.15 2.60E-05 36200.37 6,836 18,778 500.00 8,094 saturation 5.29E-06 3.62E-02 1.33E-04 9.06E-01 1.38E-04 9.42E-01 8.96E-02 8.07E-01 1.16E-04 9.33E-01 29.71 29.41 0.93269 TRUE

9 Feb 2009 (59.59 GL/a) +15GL/a JSW 34.54 0.0946 1.095 0.19 4.824 47.703 0.18 0.110 47.703 7949.13 2.60E-05 42094.07 7,949 19,891 500.00 9,411 saturation 5.29E-06 4.21E-02 1.33E-04 1.05E+00 1.38E-04 1.10E+00 8.96E-02 8.07E-01 1.16E-04 9.39E-01 34.54 29.60 0.93859 TRUE

10 Feb 2009 (59.59 GL/a) +20GL/a JSW 39.39 0.1079 1.249 0.21 5.792 49.104 0.19 0.130 49.104 8805.18 2.97E-05 42078.99 8,805 saturation 500.00 10,717 saturation 5.45E-06 4.40E-02 1.36E-04 1.10E+00 1.42E-04 1.14E+00 8.96E-02 8.07E-01 1.17E-04 9.40E-01 36.10 29.66 0.94048 TRUE



wdith per

m/s

reach total

m3/s




Slope, Sf HECRAS INPUT porosity 0.2 loss past roots (m/s) 2.E-06 6.E-04 6.E+00


Water Balance


Scenarios name

Reach

volume GL/y

Reach peak

volume

(GL/d)

Reach peak

m3/s

Ave Velocity

(m/s)

Ave Flow

Area (m2)

Ave Top

Width (m) Froude no

Ave Water

Depth (m)

Wetted

Perimeter

distance to

zero volume

(m)

loss m3 per

second

time peak

volume to

zero (s)

distance to

zero volume

(m)

Surface

water

footprint

Riparian

recharge

influence

steady state

distance (m)

Steady

state

footprint

width per

m/s total m3/s

width per

m/s total m3/s

width per


width per

m/s total m3/s

SW footprint

loss per year

per reach

(GL)

Groundwater

loss per year

per reach

(GL)

Limited loss

to next reach

(m3/s)

Potential for

ponding

1 Peak max (90 GL/a) 15.10 0.0414 0.479 0.18 3.614 43.300 0.20 0.090 43.303 3828.72 2.30E-05 20808.65 3,829 30,965 285.00 826 27,963 4.81E-06 1.84E-02 1.20E-04 4.61E-01 1.25E-04 4.79E-01 4.00E-03 4.71E-01 5.80E-04 4.93E-01 15.10 15.56 0.47893617 FALSE

2 #DIV/0! #DIV/0! n/a 285.00 n/a 5.75E-04 FALSE






8 Feb 2009 (59.59 GL/a) +10GL/a JSW 0.29 0.0008 0.009 reach dry #DIV/0! #VALUE! #VALUE! #VALUE! #VALUE! 285.00 16 27,153 #VALUE! #VALUE! #VALUE! 7.87E-05 9.27E-03 5.75E-04 #VALUE! #VALUE! #VALUE! #VALUE! #VALUE!

9 Feb 2009 (59.59 GL/a) +15GL/a JSW 4.95 0.0135 0.157 0.11 1.536 39.801 0.18 0.040 39.801 1363.99 1.27E-05 12396.03 1,364 21,375 285.00 271 20,282 4.42E-06 6.03E-03 1.11E-04 1.51E-01 1.15E-04 1.57E-01 1.31E-03 1.54E-01 5.79E-04 1.62E-01 4.95 5.10 0.15682669 FALSE

10 Feb 2009 (59.59 GL/a) +20GL/a JSW 9.73 0.0267 0.309 0.14 2.346 41.202 0.060 41.202 2592.18 1.70E-05 18177.08 2,592 22,603 285.00 532 20,543 4.57E-06 1.19E-02 1.14E-04 2.97E-01 1.19E-04 3.09E-01 2.58E-03 3.04E-01 5.79E-04 3.18E-01 9.73 10.03 0.30852672 FALSE


Appendix B – Scenario output


REACH 1 Yandi discharge - Marillana Reach 1 (BHP discharge)



width per

m/s

reach total

m3/s






Water Balance


Scenarios name

Reach

volume GL/y

Reach peak

volume

(GL/d)

Reach peak

m3/s

Ave Velocity

(m/s)

Ave Flow

Area (m2)

Ave Top

Width (m) Froude no

Ave Water

Depth (m)

Wetted

Perimeter

distance to

zero volume

(m)

loss m3 per

second

time peak

volume to

zero (s)

distance to

zero volume

(m)

Surface

water

footprint

Riparian

recharge

influence

steady state

distance (m)

Steady

state

footprint

width per

m/s total m3/s

width per

m/s total m3/s

width per


width per

m/s total m3/s

SW

footprint

loss per

year per

Groundwat

er loss per

year per

reach (GL)

Limited

loss to

next

reach

Potential

for

ponding


2 Peak max (90 GL/a) - d/s of operation 0.00 0.0000 0.000 0.00 0.000 0.000 0.00 0.000 0.000 #DIV/0! 0.00E+00 #DIV/0! 0 n/a 140.00 0 n/a 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 3.27E-05 0.00E+00 0.00 0.00 0 FALSE

3 Peak max (90 GL/a) - d/s of operation;BHP in JC 0.00 0.0000 0.000 0.00 0.000 0.000 0.00 0.000 0.000 #DIV/0! 0.00E+00 #DIV/0! 0 n/a 140.00 0 n/a 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 3.27E-05 0.00E+00 0.00 0.00 0 FALSE

4 Peak max (90 GL/a)+JSW (5 GL/a) 15.00 0.0411 0.476 0.18 2.925 27.000 0.15 0.150 27.003 6097.65 1.38E-05 34405.95 6,098 saturation 140.00 13,339 saturation 3.00E-06 4.00E-03 7.50E-05 1.00E-01 7.80E-05 1.04E-01 6.23E-03 3.74E-02 3.57E-05 4.76E-02 3.29 1.50 0.04765 TRUE



7 Peak max (90 GL/a)+JSW(20 GL/a) 15.00 0.041 0.476 0.18 2.925 27.000 0.15 0.150 27.003 6097.65 1.38E-05 34405.95 6,098 saturation 140.00 13,339 saturation 3.00E-06 4.00E-03 7.50E-05 1.00E-01 7.80E-05 1.04E-01 6.23E-03 3.74E-02 3.57E-05 4.76E-02 3.29 1.50 0.04765 TRUE

8 #DIV/0! 0.00E+00 #DIV/0! 0 n/a 140.00 0 n/a 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 3.27E-05 0.00E+00 0.00 0.00 0 FALSE






wdith per

m/s

reach total

m3/s






Water Balance


Scenarios name

Reach

volume GL/y

Reach peak

volume

(GL/d)

Reach peak

m3/s

Ave Velocity

(m/s)

Ave Flow

Area (m2)

Ave Top

Width (m) Froude no

Ave Water

Depth (m)

Wetted

Perimeter

distance to

zero volume

(m)

loss m3 per

second

time peak

volume to

zero (s)

distance to

zero volume

(m)

Surface

water

footprint

Riparian

recharge

influence

steady state

distance (m)

Steady

state

footprint

width per

m/s total m3/s

width per

m/s total m3/s

width per


width per

m/s total m3/s

SW footprint

loss per year

per reach

(GL)

Groundwater

loss per year

per reach

(GL)

Limited loss

to next reach

(m3/s)

Potential for

ponding


2 Peak max (90 GL/a) - d/s of operation #DIV/0! #DIV/0! n/a 150.00 n/a 3.50E-05 FALSE

3 Peak max (90 GL/a) - d/s of operation;BHP in JC #DIV/0! #DIV/0! n/a 150.00 n/a 3.50E-05 FALSE











wdith per

m/s

reach total

m3/s






Water Balance


Scenarios name

Reach

volume GL/y

Reach peak

volume

(GL/d)

Reach peak

m3/s

Ave Velocity

(m/s)

Ave Flow

Area (m2)

Ave Top

Width (m) Froude no

Ave Water

Depth (m)

Wetted

Perimeter

distance to

zero volume

(m)

loss m3 per

second

time peak

volume to

zero (s)

distance to

zero volume

(m)

Surface

water

footprint

Riparian

recharge

influence

steady state

distance (m)

Steady

state

footprint

width per

m/s total m3/s

width per

m/s total m3/s

width per


width per

m/s total m3/s

SW footprint

loss per year

per reach

(GL)

Groundwater

loss per year

per reach

(GL)

Limited loss

to next reach

(m3/s)

Potential for

ponding


2 Peak max (90 GL/a) - d/s of operation 0.00 0.0000 0.000 #DIV/0! 0.00E+00 #DIV/0! 0 n/a 200.00 0 n/a 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 4.44E-05 0.00E+00 0.00 0.00 0 FALSE

3 Peak max (90 GL/a) - d/s of operation;BHP in JC 0.00 0.0000 0.000 #DIV/0! 0.00E+00 #DIV/0! 0 n/a 200.00 0 n/a 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 4.44E-05 0.00E+00 0.00 0.00 0 FALSE








REACH 1 Yandi discharge - Marillana Reach 4 (DO3, DO8, DO1/4 and DO5)



width per

m/s

reach total

m3/s






Water Balance


Scenarios name

Reach

volume GL/y

Reach peak

volume

(GL/d)

Reach peak

m3/s

Ave Velocity

(m/s)

Ave Flow

Area (m2)

Ave Top

Width (m) Froude no

Ave Water

Depth (m)

Wetted

Perimeter

distance to

zero volume

(m)

loss m3 per

second

time peak

volume to

zero (s)

distance to

zero volume

(m)

Surface

water

footprint

Riparian

recharge

influence

steady state

distance (m)

Steady

state

footprint

width per

m/s total m3/s

width per

m/s total m3/s

width per


width per

m/s total m3/s

SW

footprint

loss per

year per

Groundwat

er loss per

year per

reach (GL)

Limited

loss to

next

reach

Potential

for

ponding


2 Peak max (90 GL/a) - d/s of operation 0.00 0.0000 0.000 0.00 0.000 0.000 0.00 0.000 0.000 #DIV/0! 0.00E+00 #DIV/0! 0 n/a 120.00 0 n/a 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 2.63E-05 0.00E+00 0.00 0.00 0 FALSE










REACH 1 Yandi discharge - Marillana Reach 5 (DO2)



width per

m/s

reach total

m3/s






Water Balance


Scenarios name

Reach

volume GL/y

Reach peak

volume

(GL/d)

Reach peak

m3/s

Ave Velocity

(m/s)

Ave Flow

Area (m2)

Ave Top

Width (m) Froude no

Ave Water

Depth (m)

Wetted

Perimeter

distance to

zero volume

(m)

loss m3 per

second

time peak

volume to

zero (s)

distance to

zero volume

(m)

Surface

water

footprint

Riparian

recharge

influence

steady state

distance (m)

Steady

state

footprint

width per

m/s total m3/s

width per

m/s total m3/s

width per


width per

m/s total m3/s

SW

footprint

loss per

year per

Groundwat

er loss per

year per

reach (GL)

Limited

loss to

next

reach

Potential

for

ponding


2 Peak max (90 GL/a) - d/s of operation 0.00 0.0000 0.000 #DIV/0! 0.00E+00 #DIV/0! 0 n/a 280.00 0 n/a 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 6.13E-05 0.00E+00 0.00 0.00 0 FALSE












wdith per

m/s

reach total

m3/s






Water Balance


Scenarios name

Reach

volume GL/y

Reach peak

volume

(GL/d)

Reach peak

m3/s

Ave Velocity

(m/s)

Ave Flow

Area (m2)

Ave Top

Width (m) Froude no

Ave Water

Depth (m)

Wetted

Perimeter

distance to

zero volume

(m)

loss m3 per

second

time peak

volume to

zero (s)

distance to

zero volume

(m)

Surface

water

footprint

Riparian

recharge

influence

steady state

distance (m)

Steady

state

footprint

width per

m/s total m3/s

width per

m/s total m3/s

width per


width per

m/s total m3/s

SW footprint

loss per year

per reach

(GL)

Groundwater

loss per year

per reach

(GL)

Limited loss

to next reach

(m3/s)

Potential for

ponding

1 Peak max (90 GL/a) 24.67 0.0676 0.782 0.21 4.096 35.025 0.19 0.130 35.025 7730.69 2.14E-05 36597.17 7,731 saturation 460.00 7,034 saturation 3.89E-06 1.21E-02 9.73E-05 3.02E-01 1.01E-04 3.14E-01 4.76E-02 2.86E-01 1.11E-04 3.45E-01 9.91 10.89 0.31421449 FALSE

2 Peak max (90 GL/a) - d/s of operation 46.39 0.1271 1.471 0.26 5.915 37.727 0.19 0.180 37.727 13498.30 2.80E-05 52560.32 13,498 saturation 460.00 13,193 saturation 4.19E-06 1.30E-02 1.05E-04 3.25E-01 1.09E-04 3.38E-01 4.76E-02 2.86E-01 1.12E-04 3.46E-01 10.67 10.92 0.33845338 FALSE

3 Peak max (90 GL/a) - d/s of operation;BHP in JC 31.39 0.0860 0.995 0.23 4.628 35.835 0.19 0.145 35.835 9615.97 2.34E-05 42612.06 9,616 saturation 460.00 8,944 saturation 3.98E-06 1.24E-02 9.95E-05 3.09E-01 1.04E-04 3.21E-01 4.76E-02 2.86E-01 1.11E-04 3.46E-01 10.14 10.90 0.32148595 FALSE

4 Peak max (90 GL/a)+JSW (5 GL/a) 29.66 0.081 0.940 0.23 4.628 35.835 0.19 0.145 35.835 9084.23 2.34E-05 40255.72 9,084 saturation 460.00 8,450 saturation 3.98E-06 1.24E-02 9.95E-05 3.09E-01 1.04E-04 3.21E-01 4.76E-02 2.86E-01 1.11E-04 3.46E-01 10.14 10.90 0.32148595 FALSE




8 Peak max (90 GL/a)+JSW (5 GL/a) - d/s of operation 51.39 0.1408 1.630 0.27 6.295 38.267 0.19 0.190 38.267 14741.95 2.93E-05 55594.03 14,742 saturation 460.00 14,607 saturation 4.25E-06 1.32E-02 1.06E-04 3.30E-01 1.11E-04 3.43E-01 4.76E-02 2.86E-01 1.12E-04 3.46E-01 10.83 10.93 0.34330102 FALSE



11 Peak max (90 GL/a)+JSW (20 GL/a) - d/s of operation 66.39 0.1819 2.105 0.29 7.467 39.888 0.20 0.220 39.888 18270.72 3.33E-05 63212.33 18,271 saturation 460.00 18,840 saturation 4.43E-06 1.37E-02 1.11E-04 3.44E-01 1.15E-04 3.58E-01 4.76E-02 2.86E-01 1.12E-04 3.47E-01 11.28 10.94 0.34702281 TRUE




width per

m/s

reach total

m3/s




Slope, Sf HECRAS INPUT porosity 0.2 loss past roots (m/s) -5.E-08 -1.E-05 -5.E-02

Time to saturate alluvials (days) 125 Weeli Wolli Spring Baseflow 4.2 ML/day

Water Balance


Scenarios name

Reach

volume GL/y

Reach peak

volume

(GL/d)

Reach peak

m3/s

Ave Velocity

(m/s)

Ave Flow

Area (m2)

Ave Top

Width (m) Froude no

Ave Water

Depth (m)

Wetted

Perimeter

distance to

zero volume

(m)

loss m3 per

second

time peak

volume to

zero (s)

distance to

zero volume

(m)

Surface

water

footprint

Riparian

recharge

influence

steady state

distance (m)

Steady

state

footprint

width per

m/s total m3/s

width per

m/s total m3/s

width per


width per

m/s total m3/s

SW

footprint

loss per

year per

Groundwat

er loss per

year per

reach (GL)

Limited

loss to

next

reach

Potential

for

ponding

1 Peak max (90 GL/a) 40.00 0.110 1.268 0.13 25.000 25.000 17563.12 9.39E-06 135100.90 17,563 saturation 200.00 175,824 saturation 2.77E-06 1.25E-02 6.94E-05 3.13E-01 7.22E-05 3.25E-01 2.00E-02 -4.86E-02 -3.59E-06 -1.61E-02 10.25 -0.51 -0.0161 TRUE

2 Peak max (90 GL/a) - d/s of operation 40.00 0.110 1.268 0.13 25.000 25.000 17563.12 9.39E-06 135100.90 17,563 saturation 200.00 175,824 saturation 2.77E-06 1.25E-02 6.94E-05 3.13E-01 7.22E-05 3.25E-01 2.00E-02 -4.86E-02 -3.59E-06 -1.61E-02 10.25 -0.51 -0.0161 TRUE

3 Peak max (90 GL/a) - d/s of operation;BHP in JC 40.00 0.110 1.268 0.13 25.000 25.000 17563.12 9.39E-06 135100.90 17,563 saturation 200.00 175,824 saturation 2.77E-06 1.25E-02 6.94E-05 3.13E-01 7.22E-05 3.25E-01 2.00E-02 -4.86E-02 -3.59E-06 -1.61E-02 10.25 -0.51 -0.0161 TRUE

4 Peak max (90 GL/a)+JSW (5 GL/a) 40.00 0.110 1.268 0.13 25.000 25.000 17563.12 9.39E-06 135100.90 17,563 saturation 200.00 175,824 saturation 2.77E-06 1.25E-02 6.94E-05 3.13E-01 7.22E-05 3.25E-01 2.00E-02 -4.86E-02 -3.59E-06 -1.61E-02 10.25 -0.51 -0.0161 TRUE




8 Peak max (90 GL/a)+JSW(5 GL/a) - d/s of operation 40.00 0.110 1.268 0.13 25.000 25.000 17563.12 9.39E-06 135100.90 17,563 saturation 200.00 175,824 saturation 2.77E-06 1.25E-02 6.94E-05 3.13E-01 7.22E-05 3.25E-01 2.00E-02 -4.86E-02 -3.59E-06 -1.61E-02 10.25 -0.51 -0.0161 TRUE








wdith per

m/s

reach total

m3/s






Water Balance


Scenarios name

Reach

volume GL/y

Reach peak

volume

(GL/d)

Reach peak

m3/s

Ave Velocity

(m/s)

Ave Flow

Area (m2)

Ave Top

Width (m) Froude no

Ave Water

Depth (m)

Wetted

Perimeter

distance to

zero volume

(m)

loss m3 per

second

time peak

volume to

zero (s)

distance to

zero volume

(m)

Surface

water

footprint

Riparian

recharge

influence

steady state

distance (m)

Steady

state

footprint

width per

m/s total m3/s

width per

m/s total m3/s

width per


width per

m/s total m3/s

SW footprint

loss per year

per reach

(GL)

Groundwater

loss per year

per reach

(GL)

Limited loss

to next reach

(m3/s)

Potential for

ponding

1 Peak max (90 GL/a) 40.51 0.1110 1.285 0.13 25.000 25.000 17786.72 9.39E-06 136820.91 17,787 saturation 150.00 35,579 saturation 2.77E-06 2.29E-02 6.94E-05 5.74E-01 7.22E-05 5.97E-01 2.75E-02 2.48E-01 3.61E-05 2.99E-01 18.83 9.42 0.2985812 TRUE

2 Peak max (90 GL/a) - d/s of operation 40.51 0.1110 1.285 0.13 25.000 25.000 17786.72 9.39E-06 136820.91 17,787 saturation 150.00 35,579 saturation 2.77E-06 2.29E-02 6.94E-05 5.74E-01 7.22E-05 5.97E-01 2.75E-02 2.48E-01 3.61E-05 2.99E-01 18.83 9.42 0.2985812 TRUE

3 Peak max (90 GL/a) - d/s of operation;BHP in JC 40.51 0.1110 1.285 0.13 25.000 25.000 17786.72 9.39E-06 136820.91 17,787 saturation 150.00 35,579 saturation 2.77E-06 2.29E-02 6.94E-05 5.74E-01 7.22E-05 5.97E-01 2.75E-02 2.48E-01 3.61E-05 2.99E-01 18.83 9.42 0.2985812 TRUE

4 Peak max (90 GL/a)+JSW (5 GL/a) 40.51 0.1110 1.285 0.13 25.000 25.000 17786.72 9.39E-06 136820.91 17,787 saturation 150.00 35,579 saturation 2.77E-06 2.29E-02 6.94E-05 5.74E-01 7.22E-05 5.97E-01 2.75E-02 2.48E-01 3.61E-05 2.99E-01 18.83 9.42 0.2985812 TRUE




8 Peak max (90 GL/a)+JSW(5 GL/a) - d/s of operation 40.51 0.1110 1.285 0.13 25.000 25.000 17786.72 9.39E-06 136820.91 17,787 saturation 150.00 35,579 saturation 2.77E-06 2.29E-02 6.94E-05 5.74E-01 7.22E-05 5.97E-01 2.75E-02 2.48E-01 3.61E-05 2.99E-01 18.83 9.42 0.2985812 TRUE




REACH 1 HD1 + Yandi discharge - Weeli Wolli Reach 3 (DO6)



width per

m/s

reach total

m3/s






Water Balance


Scenarios name

Reach

volume GL/y

Reach peak

volume

(GL/d)

Reach peak

m3/s

Ave Velocity

(m/s)

Ave Flow

Area (m2)

Ave Top

Width (m) Froude no

Ave Water

Depth (m)

Wetted

Perimeter

distance to

zero volume

(m)

loss m3 per

second

time peak

volume to

zero (s)

distance to

zero volume

(m)

Surface

water

footprint

Riparian

recharge

influence

steady state

distance (m)

Steady

state

footprint

width per

m/s total m3/s

width per

m/s total m3/s

width per


width per

m/s total m3/s

SW

footprint

loss per

year per

Groundwat

er loss per

year per

reach (GL)

Limited

loss to

next

reach

Potential

for

ponding


2 Peak max (90 GL/a) - d/s of operation 34.70 0.0951 1.100 0.28 4.293 32.228 0.23 0.145 32.228 11819.20 2.59E-05 42424.14 11,819 saturation 77.00 53,193 saturation 3.58E-06 8.41E-03 8.95E-05 2.10E-01 9.31E-05 2.19E-01 4.02E-03 3.62E-02 2.07E-05 4.86E-02 6.90 1.53 0.04861 TRUE

3 Peak max (90 GL/a) - d/s of operation;BHP in JC 34.70 0.0951 1.100 0.28 4.293 32.228 0.23 0.145 32.228 11819.20 2.59E-05 42424.14 11,819 saturation 77.00 53,193 saturation 3.58E-06 8.41E-03 8.95E-05 2.10E-01 9.31E-05 2.19E-01 4.02E-03 3.62E-02 2.07E-05 4.86E-02 6.90 1.53 0.04861 TRUE





8 Peak max (90 GL/a)+JSW(5 GL/a) - d/s of operation 34.70 0.0951 1.100 0.28 4.293 32.228 0.23 0.145 32.228 11819.20 2.59E-05 42424.14 11,819 saturation 77.00 53,193 saturation 3.58E-06 8.41E-03 8.95E-05 2.10E-01 9.31E-05 2.19E-01 4.02E-03 3.62E-02 2.07E-05 4.86E-02 6.90 1.53 0.04861 TRUE







wdith per

m/s

reach total

m3/s






Water Balance


Scenarios name

Reach

volume GL/y

Reach peak

volume

(GL/d)

Reach peak

m3/s

Ave Velocity

(m/s)

Ave Flow

Area (m2)

Ave Top

Width (m) Froude no

Ave Water

Depth (m)

Wetted

Perimeter

distance to

zero volume

(m)

loss m3 per

second

time peak

volume to

zero (s)

distance to

zero volume

(m)

Surface

water

footprint

Riparian

recharge

influence

steady state

distance (m)

Steady

state

footprint

width per

m/s total m3/s

width per

m/s total m3/s

width per


width per

m/s total m3/s

SW footprint

loss per year

per reach

(GL)

Groundwater

loss per year

per reach

(GL)

Limited loss

to next reach

(m3/s)

Potential for

ponding


2 Peak max (90 GL/a) - d/s of operation 33.17 0.0909 1.052 0.26 4.130 33.000 0.22 0.140 33.006 11030.98 2.50E-05 42117.96 11,031 saturation 80.00 49,059 saturation 3.66E-06 1.69E-02 9.17E-05 4.24E-01 9.53E-05 4.40E-01 8.20E-03 7.39E-02 2.14E-05 9.90E-02 13.89 3.12 0.09904462 TRUE

3 Peak max (90 GL/a) - d/s of operation;BHP in JC 33.17 0.0909 1.052 0.26 4.130 33.000 0.22 0.140 33.006 11030.98 2.50E-05 42117.96 11,031 saturation 80.00 49,059 saturation 3.66E-06 1.69E-02 9.17E-05 4.24E-01 9.53E-05 4.40E-01 8.20E-03 7.39E-02 2.14E-05 9.90E-02 13.89 3.12 0.09904462 TRUE













width per

m/s

reach total

m3/s






Water Balance


Scenarios name

Reach

volume GL/y

Reach peak

volume

(GL/d)

Reach peak

m3/s

Ave Velocity

(m/s)

Ave Flow

Area (m2)

Ave Top

Width (m) Froude no

Ave Water

Depth (m)

Wetted

Perimeter

distance to

zero volume

(m)

loss m3 per

second

time peak

volume to

zero (s)

distance to

zero volume

(m)

Surface

water

footprint

Riparian

recharge

influence

steady state

distance (m)

Steady

state

footprint

width per

m/s total m3/s

width per

m/s total m3/s

width per


width per

m/s total m3/s

SW

footprint

loss per

year per

Groundwat

er loss per

year per

reach (GL)

Limited

loss to

next

reach

Potential

for

ponding

1 Peak max (90 GL/a) 44.80 0.1227 1.421 0.23 6.788 50.500 0.19 0.150 50.504 9737.63 3.33E-05 42655.69 9,738 saturation 500.00 12,173 saturation 5.60E-06 4.52E-02 1.40E-04 1.13E+00 1.46E-04 1.18E+00 8.96E-02 8.07E-01 1.17E-04 9.42E-01 37.13 29.70 0.94173 TRUE

2 Peak max (90 GL/a) - d/s of operation 65.76 0.1802 2.085 0.25 7.812 51.900 0.19 0.170 51.905 13907.80 3.69E-05 56496.17 13,908 saturation 500.00 17,845 saturation 5.76E-06 4.65E-02 1.44E-04 1.16E+00 1.50E-04 1.21E+00 8.96E-02 8.07E-01 1.17E-04 9.43E-01 38.16 29.74 0.94298 TRUE

3 Peak max (90 GL/a) - d/s of operation;BHP in JC 51.30 0.1405 1.627 0.22 6.286 49.804 0.19 0.140 49.804 11306.30 3.15E-05 51644.65 11,306 saturation 500.00 13,948 saturation 5.53E-06 4.46E-02 1.38E-04 1.12E+00 1.44E-04 1.16E+00 8.96E-02 8.07E-01 1.17E-04 9.41E-01 36.61 29.68 0.94111 TRUE

4 Peak max (90 GL/a)+JSW (5 GL/a) 49.56 0.1358 1.572 0.23 7.041 50.854 0.19 0.155 50.854 10698.07 3.42E-05 45942.89 10,698 saturation 500.00 13,462 saturation 5.64E-06 4.55E-02 1.41E-04 1.14E+00 1.47E-04 1.19E+00 8.96E-02 8.07E-01 1.17E-04 9.42E-01 37.38 29.71 0.94205 TRUE




8 Peak max (90 GL/a)+JSW(5 GL/a) - d/s of operation 70.61 0.1935 2.239 0.27 9.400 54.006 0.19 0.200 54.006 14351.93 4.23E-05 52913.08 14,352 saturation 500.00 19,122 saturation 5.99E-06 4.84E-02 1.50E-04 1.21E+00 1.56E-04 1.26E+00 8.96E-02 8.07E-01 1.17E-04 9.45E-01 39.70 29.80 0.94487 TRUE




HD1 + Yandi discharge - Weeli Wolli Reach 6


Alluvials Rates m/s

wdith per

m/s

reach total

m3/s

HECRAS INPUT Riparian veg width (m) 285 Infiltration (mm/h) 10 2.78E-06

HECRAS INPUT channel length (m) 10728 Evaporation (mm/y) 3500 1.11E-07

HECRAS INPUT channel depth (m) 32 ET (m/s) ET = 15% evap 1.70.E-08 5.E-06 5.E-02 536mm/year

HECRAS INPUT porosity 0.2 loss past roots (m/s) 2.E-06 6.E-04 6.E+00


Water Balance

Data from HECRAS averages Surfacxe water Groundwater Evaporation loss Infiltration loss SW footprint loss ET loss Past root zone lossGroundwater loss

name

Reach

volume GL/y

Reach peak

volume

(GL/d)

Reach peak

m3/s

Ave Velocity

(m/s)

Ave Flow

Area (m2)

Ave Top

Width (m) Froude no

Ave Water

Depth (m)

Wetted

Perimeter

distance to

zero volume

(m)

loss m3 per

second

time peak

volume to

zero (s)

distance to

zero volume

(m)

Surface

water

footprint

Riparian

recharge

influence

steady state

distance (m)

Steady

state

footprint

width per

m/s total m3/s

width per

m/s total m3/s

width per


width per

m/s total m3/s

SW footprint

loss per year

per reach

(GL)

Groundwater

loss per year

per reach

(GL)

Limited loss

to next reach

(m3/s)

Potential for

ponding

Peak max (90 GL/a) 15.10 0.0414 0.479 0.18 3.614 43.300 0.20 0.090 43.303 3828.72 2.30E-05 20808.65 3,829 30,965 285.00 826 27,963 4.81E-06 1.84E-02 1.20E-04 4.61E-01 1.25E-04 4.79E-01 4.00E-03 4.71E-01 5.80E-04 4.93E-01 15.10 15.56 0.47893617 FALSE

Peak max (90 GL/a) - d/s of operation 36.03 0.0987 1.142 0.22 4.944 45.403 0.20 0.120 45.403 8709.66 2.88E-05 39640.71 8,710 19,885 285.00 1,970 13,145 5.04E-06 4.39E-02 1.26E-04 1.10E+00 1.31E-04 1.14E+00 9.53E-03 1.12E+00 5.80E-04 1.18E+00 36.03 37.10 1.14235555 FALSE

Peak max (90 GL/a) - d/s of operation;BHP in JC 21.62 0.0592 0.686 0.17 3.184 42.602 0.19 0.080 42.602 5570.53 2.10E-05 32583.93 5,571 16,746 285.00 1,183 12,358 4.73E-06 2.63E-02 1.18E-04 6.59E-01 1.23E-04 6.86E-01 5.72E-03 6.74E-01 5.80E-04 7.06E-01 21.62 22.27 0.68555324 FALSE

Peak max (90 GL/a)+JSW (5 GL/a) 19.85 0.0544 0.630 0.20 4.050 44.003 0.20 0.100 44.003 4952.78 2.50E-05 25215.46 4,953 32,089 285.00 1,086 28,222 4.88E-06 2.42E-02 1.22E-04 6.05E-01 1.27E-04 6.30E-01 5.26E-03 6.19E-01 5.80E-04 6.48E-01 19.85 20.45 0.62956725 FALSE



Peak max (90 GL/a)+JSW (20 GL/a) 34.22 0.0937 1.085 0.22 4.944 45.403 0.20 0.120 45.403 8272.24 2.88E-05 37649.88 8,272 35,408 285.00 1,871 29,007 5.04E-06 4.17E-02 1.26E-04 1.04E+00 1.31E-04 1.08E+00 9.05E-03 1.07E+00 5.80E-04 1.12E+00 34.22 35.23 1.08498426 FALSE

Peak max (90 GL/a)+JSW(5 GL/a) - d/s of operation 40.81 0.1118 1.294 0.24 5.866 46.804 0.21 0.140 46.804 9571.87 3.26E-05 39666.55 9,572 20,747 285.00 2,231 13,406 5.19E-06 4.97E-02 1.30E-04 1.24E+00 1.35E-04 1.29E+00 1.08E-02 1.27E+00 5.80E-04 1.33E+00 40.81 42.02 1.29417078 FALSE

Peak max (90 GL/a)+JSW(10 GL/a) - d/s of operation 45.81 0.1255 1.453 0.24 5.866 46.804 0.21 0.140 46.804 10744.52 3.26E-05 44526.10 10,745 saturation 285.00 2,505 13,680 5.19E-06 5.57E-02 1.30E-04 1.39E+00 1.35E-04 1.45E+00 1.21E-02 1.43E+00 5.80E-04 1.50E+00 45.74 47.16 1.45051155 FALSE




Addendums– Scenario 7 to 9 including BHPBIO

Jinidi


Scenario 7: Comparison of different discharge rate combinations

This scenario investigates the response of the creek systems by changing the combination of

the volume discharged from Hope Downs 1 and RTIO Yandicoogina. The 90, 95, 100 GL/year

discharge rate options were investigated, which are equivalent to existing Scenarios 7d, 7e and

7f but with different discharge rate combinations.

Modelling results

A comparison of the discharge volumes and the subsequent estimated footprint distances for

the existing and additional scenarios are shown in Table 11. The differences between the

estimated discharge footprints for the existing and additional scenarios are less than 0.3 %.

Based on the model results, it was determined that changing the combination of the volume

discharged from Hope Downs 1 or RTIO Yandicoogina would unlikely to have a notable effect

on the footprint distances

Table 11: A comparison of the discharge volumes and estimated footprint distances for the existing and

additional 90, 95 and 100 GL/year discharge rate options

Discharge rate (GL/year) Maximum footprint (km)

Total BHPBIO

Yandi

RTIO

Yandi

Hope

Downs 1

Proposed

Marillana Creek

outlet

Hope Downs

1 outlet

Weeli Wolli –

Marillana Creek

confluence

90 (7d) 15 40 35 16.1 32.7 12.9

95 (7e) 15 40 40 17.2 33.9 14.1

100(7f) 15 45 40 18.3 35.0 15.2

90 15 45 30 16.0 32.7 12.9

95 15 45 35 17.2 33.8 14.1

100 15 50 35 18.3 34.9 15.2

Bold – existing scenarios

Italic – additional scenarios


Scenario 8: Hope Downs 1 discharge rate options

In this scenario we investigate the response of the Weeli Wolli Creek system from Hope Downs

1 discharge alone, at a continual rate of 25 (the current average discharge rate), 30, 35 and 40

(the licensed maximum abstraction rate) GL/year. This scenario investigates the contribution

of Hope Downs 1 water on the progression of the wetting front along Weeli Wolli Creek.

Modelling results

The footprint distances, measured downstream from the Hope Downs 1 discharge location and

the confluence of Marillana and Weeli Wolli Creeks, for the modelled discharge options are

presented in Figure 30 and are summarised in Table 12. Modelling indicated that the

footprint distance would extend from approximately 3.2 km to 7.3 km down gradient from the

Weeli Wolli – Marillana Creek confluence for modelled volumes 25 GL/year to 40 GL/year,

the maximum volume modelled. It is assumed that the creek conditions are uniform for 8 km

downstream from the confluence of Marillana and Weeli Wolli Creeks. As all of the footprints

for the modelled scenarios terminate within this reach, it is expected that the footprint

distance would increase linearly with discharge (Figure 31 and Figure 32).

Table 12: Estimated discharge footprints for Weeli Wolli Creek for different discharge options

Scenario 8 Weeli Wolli Creek from Hope Downs 1 discharge

outlet

Footprint distance past the

confluence of Marillana

and Weeli Wolli Creeks

(km) Steady state

distance (km)

Surface water

expression (km)

Maximum

footprint (km)

a: 25 GL/year 22.9 22.6 22.9 3.2

b: 30 GL/year 24.3 23.8 24.3 4.6

c: 35 GL/year 25.6 24.9 25.6 5.9

d: 40 GL/year 27.0 25.9 27.0 7.3


Figure 30: Estimated discharge footprints for Marillana and Weeli Wolli Creeks for different discharge rates.


From Hope Downs 1 outlet

10

15

20

25

30

35

10 15 20 25 30 35 40 45 50


Max f

oo

tpri

nt

(km

)


Figure 31: A plot of discharge volume versus maximum footprint measured from the Hope Downs 1 discharge

outlet (with +/- 10 % error margin). The plot shows a linear increase in footprint distance with discharge.

From Weeli Wolli - Marillana Creek confluence

0

2

4

6

8

10

10 15 20 25 30 35 40 45 50


Max f

oo

tpri

nt

(km

)


Figure 32: A plot of discharge volume versus maximum footprint measured from the Weeli Wolli – Marillana

Creek confluence (with +/- 10 % error margin). The plot shows a linear increase in footprint distance with

discharge.


Scenario 9: Impacts of dewatering discharge from the BHP Jinidi Iron Ore Project

The BHP Jinidi Project is located approximately 12 km east of the RTIO Hope Downs 1 mine.

Based on the information provided in their referral document (BHPBIO 2011), groundwater

abstraction as required for operation could be up to 7 GL/year. Mine-derived water would be

used for construction and operational purposes but there is the potential for surplus

groundwater to be discharged into local watercourses in the catchment. The proposed location

for disposal of surplus water is to the south of the Project Area, approximately 17 km upstream

of the Hope Downs 1 discharge outlet. For the purpose of this study, a „one-reach‟ discharge

model was developed to assess the contribution of Jinidi water, at a continual rate of 1, 3, 5

and 7 (the maximum predicted abstraction rate) GL/year, on the progression of the wetting

front along Weeli Wolli Creek. (It is important to note that results from the model are

preliminary and that additional survey data and reach breakdowns are recommended if more

comprehensive assessment of the impacts is required.)

Modelling results

Results for the modelled discharge rates are presented in Figure 33 and are summarised in

Table 13. The cumulative effects associated with surplus water discharge from the BHPBIO

Yandi, RTIO Yandi and Hope Downs 1 operations (Scenario 6) and from the proposed

BHPBIO Jinidi mine along Marillana and Weeli Wolli Creek systems are illustrated in Figure

34.

It was demonstrated that surplus water released from the proposed Jinidi outlet would

terminate before the Hope Downs 1 discharge location and therefore would not contribute to

the footprint distances estimated at Weeli Wolli Creek. Based on the preliminary modelling

results, a discharge footprint of 11.3 km was estimated for the maximum modelled 7 GL/year.

Table 13: Estimated discharge footprints for Weeli Wolli Creek from the proposed BHPBIO Jinidi discharge

outlet

Scenario 9 Weeli Wolli Creek from the proposed Jinidi discharge outlet

Steady state distance

(km)

Surface water

expression (km)

Maximum footprint

(km)

a: 1 GL/year 1.6 0.9 1.6

b: 3 GL/year 4.9 2.4 4.9

c: 5 GL/year 8.1 3.9 8.1

d: 7 GL/year 11.3 5.3 11.3


Figure 33: Estimated discharge footprints for Weeli Wolli Creek from the proposed BHPBIO Jinidi -surface

water management area and assumed discharge outlet location


Figure 34: Estimated wetting fronts as a result of surplus water discharge from the BHPBIO Yandi, RTIO

Yandi and Hope Downs 1 operations (Scenario 6) and from the proposed BHP Jinidi mine along Marillana

and Weeli Wolli Creeks.


References

A.J. Peck and Associates Pty Ltd (1997) Yandi (HIY) Mine: Hydrology of Marillana Creek,

report no RTIO-PDE-0069444.

Australian Bore Consultants Pty Ltd (1997) Yandicoogina Monitoring Bores – Bore

Completion Report, report no GDSR 4171.

BHPBilliton Iron Ore (2011) Jinidi Iron Ore Mine – Environmental Referral Document

(Final)

Biota Environmental Sciences Pty Ltd (2004) Yandi Expansion Vegetation and Flora Survey,

report no RTIO-HSE-0057589.

Biota Environmental Sciences Pty Ltd (2009) Vegetation and Flora Surveys of the Oxbow and

Junction South West Deposits, near Yandicoogina, report no RTIO-HSE-0083283.

CSIRO (2004) Water for a Healthy Country,

http://www.anbg.gov.au/cpbr/WfHC/Eucalyptus-camaldulensis/index.html

Ecosystems Research Group, University of Western Australia (2002) Possible impact of

hydrological changes to the Marillana Creek System on associated creek-line vegetation,


E.M. Mattiske and Associates (1995) Flora and Vegetation – Yandicoogina Junction Area,


Reid M., Cheng X., Banks E., Jankowski J., Jolly I., Kumar P., Lovell D., Mitchell M., Mudd G.,

Richardson S., Silburn M. and Werner A. (2009) Catalogue of conceptual models for

groundwater – stream interaction in eastern Australia, eWater Cooperative Research Centre

Technical Report.

Rio Tinto Iron Ore (2009) Guidelines for the assessment of discharge to natural creeks

(Draft), report no RTIO-PDE-0057752.

Rio Tinto Iron Ore (2010) Baseline hydrology assessment for Marillana Creek discharge,

report no RTIO-PDE-0074001

Rio Tinto Iron Ore (2008) Marillana Creek Hydrology Report, report no RTIO-PDE-

0047262.

Winter T.C., Havey J.W., Franke O.L. and Alley W.M. (1998) Groundwater and surface

water; a single resource, USGS Circular 1139, US Geological Survey, Denver, Colorado.

http://www.catchment.crc.org.au/pdfs/technical200305.pdf

http://www.anbg.gov.au/cpbr/WfHC/Eucalyptus-camaldulensis/index.html

http://www.catchment.crc.org.au/pdfs/technical200305.pdf

yandicoogina baseline hydrology

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