PINDAN PTY LTD Nickol West Karratha · The Civil Group WA Pty Ltd (thecivilgroup) and the Client...

PINDAN PTY LTD

Nickol West Karratha

Urban Water Management Plan

16th December 2011

WAPC ref: 144065, 144516, 144949, 145041

thecivilgroup ref: 7665-0

Contents 1 INTRODUCTION ................................................................................... 1

1.1 Planning Approval ............................................................................................ 1

1.2 Design Objectives ............................................................................................ 1

2 SITE CHARACTERISTICS ................................................................... 2

2.1 Existing site conditions ..................................................................................... 2

2.2 Soil characteristics ........................................................................................... 22.2.1 Geotechnical conditions ........................................................ 22.2.2 Site classification ................................................................... 2

2.3 Pre-development surface water ....................................................................... 2

2.4 Pre-development groundwater ........................................................................ 2

3 WATER SUSTAINABILITY & CONSERVATION ................................. 3

3.1 Waterwise landscaping .................................................................................... 33.1.1 Households ............................................................................ 33.1.2 Public open space ................................................................. 3

3.2 Potable water use ............................................................................................ 3

3.3 Wastewater management and potable water supply ....................................... 3

4 STORMWATER MANAGEMENT ......................................................... 4

4.1 Regional context .............................................................................................. 4

4.2 Stormwater management ................................................................................. 4

4.3 Flood management .......................................................................................... 4

4.4 Surface water quality ....................................................................................... 5

4.5 Nuisance insect management ......................................................................... 5

5 IMPLEMENTATION .............................................................................. 6

5.1 Implementation plan ......................................................................................... 6

5.2 Managing Subdivision Works .......................................................................... 6

6 COMPLIANCE WITH UWMP GUIDELINES CHECKLIST.................... 7

7 REFERENCES ...................................................................................... 9

List of Figures Figure 1.1 – Subdivision layout

Figure 2.1 – Aerial photo and natural surface contours

Figure 2.2 – Geotechnical conditions

Figure 4.1 – Design earthworks levels and overland flow paths

Figure 4.2 – Design earthworks levels and overland flow paths

Figure 4.3 – Open drain long sections

Figure 4.4 – Open drain long sections

List of Appendices Appendix A – Madigan Creek Flood Study extract

Disclaimer: This document is copyright and is published in accordance with and subject to an agreement between The Civil Group WA Pty Ltd (thecivilgroup) and the Client (Pindan Pty Ltd and Otan Karratha Pty Ltd) for whom it has been prepared (“Client”). The Client may rely on and use this document only for the purposes agreed with thecivilgroup. No other person or organisation may rely on or use this document for any purpose without first obtaining the prior written consent of thecivilgroup. If either the Client relies on or uses this document for a purpose not agreed with thecivilgroup; or any other person relies on or uses this document for any purpose without first obtaining the prior written consent of thecivilgroup they do so at their own risk and thecivilgroup will have no liability in tort, contract or otherwise for any loss, damage or injury of any kind whatsoever that may be suffered directly or indirectly as a consequence of relying on or using the estimates or assessments for any other purpose. Thecivilgroup retains the intellectual property in all documents produced in connection with the Services provided to the Client. Thecivilgroup grants the Client a licence to the intellectual property in all documents produced in connection with the Services for any purpose for which the Services were provided. If the Client is in breach of any obligation to make a payment to thecivilgroup, thecivilgroup may at its sole discretion revoke the licence. If thecivilgroup revokes the licence then the Client must return all documents produced by thecivilgroup in connection with the services, including any copies within 21 days of the date of revocation of the licence. Thecivilgroup does not warrant the accuracy of any estimates or assessments of likely development costs that thecivilgroup may prepare. The quantities and assessments of likely costs are only an indicative engineering estimate. The assessments are based on thecivilgroup’s experience on similar projects and they are only valid for the day on which they are published. Any estimates or assessments of likely costs should only be used by the Client and only for indicative budgeting purposes together with an appropriate contingency.

The Civil Group | Pindan – Nickol West Karratha UWMP | page 1

1 Introduction This Urban Water Management Plan (UWMP) has been commissioned by Otan Karratha Pty Ltd to address water management issues in Pindan’s Nickol West residential development in Karratha (the Subject Area).

Pindan’s Nickol West development is located within the Shire of Roebourne (SoR), on Lot 517 Dampier Highway (the Subject Area). The Subject Area is approximately 5km east of the Karratha town centre, immediately east of Madigan Creek.

Lot 517 is 24ha in area, and will yield approximately 300 residential dwellings when completed.

The proposed subdivision layout for the development is included as Figure 1.1.

1.1 Planning Approval The Nickol West development was rezoned from ‘Rural’ to ‘Urban Development’ under the SoR’s Town Planning Scheme No. 8, by the recent Scheme Amendment No. 20. The northern half of the site has conditional subdivision approval (WAPC Ref 144065), while a subdivision application covering the remainder of the site is currently being assessed by WAPC.

Although no Local Water Management Strategy exists for the Nickol West area, this UWMP takes surrounding developments into consideration when assessing their impact on water management within the Subject Area.

1.2 Design Objectives The design objectives for the Subject Area have been developed in consultation with the Department of Water, and are based on water management practices that are specific to the Pilbara region. These design objectives also reflect the requirements of the SoR’s Stormwater Design Guidelines for Residential Development.

No gutters/downpipes are to be installed on houses, and roof runoff will be directed onto roads by grading finished lot levels from back-to-front.

Finished levels of all lots shall be above adjacent road levels, and minimum habitable floor levels shall be 500mm above the 100 year ARI flood level.

Kerbed roads are to convey stormwater to kerb-breaks located at topographic low points, which discharge runoff into large open channels that direct the stormwater away from the urban zone.

The top water levels in the open channels for the 5 year ARI event shall be at least 300mm below the shoulder of the road.

Drainage channels should be constructed with minimum 1:4 side slopes and vegetated where possible to limit erosion of drain sides. The maximum flow velocity in open channels is not to exceed 2 m/s.

Mortared stone pitching or other suitable scour protection shall be provided in open drains at all outlet structures, kerb breaks, kerb returns, open drain junctions and bends greater than 22.5°.


2 Site characteristics

2.1 Existing site conditions The Subject Area is located immediately to the east of Madigan Creek, and north of Dampier Highway. Levels across the site range from 14mAHD to 8mAHD, generally falling from south-east to north-west. Figure 2.1 shows a recent aerial image of the site, with natural surface contours.

2.2 Soil characteristics

2.2.1 Geotechnical conditions

The existing ground conditions in the Nickol area generally consist of clayey sands and sandy clays, overlying weathered granite at depth of approximately 2-3m below existing ground level. The depth to rock beneath the surface tends to decrease as the location nears Dampier Highway.

Parts of the site have Gilgai clay material present – these materials will be ripped to a depth of 0.4m and compacted in order to be suitable for development. Figure 2.2 shows the location of geotechnical test pits and approximate boundaries of the Gilgai clays.

2.2.2 Site classification

Douglas Partners’ geotechnical report provided advice on the expected site classification of the lots in the Subject Area. Currently, the site would be classified as Class M-D, or Class H1-D. The placement of 0.7m of suitable fill material would improve the classification to Class M-D.

2.3 Pre-development surface water Surface water flow is via overland flow across the Subject Area towards Madigan Creek. There are five existing open drains through the Subject Area which convey stormwater from the existing development immediately to the east of the Subject Area.

The 100-year Madigan Creek floodplain currently infringes on the western edge of the Subject Area. A flood study for Madigan Creek has been completed by JDA Consultant Hydrologists which recommends that any approved development within the 100-year ARI flood plain is constructed so that building floor levels are 0.5m above the adjacent 100-year ARI flood level. A figure from the Madigan Creek Flood Study showing the pre- and post-development flood levels along Madigan Creek for the peak 100-year ARI flood event has been included in Appendix A.

2.4 Pre-development groundwater Shallow groundwater is not an issue at this site due to the near-impervious clayey soil conditions at the surface across the Subject Area, and there is no interaction between surface water and groundwater. Surface runoff currently discharges via overland flow to the adjacent creek without infiltrating on site.


3 Water sustainability & conservation Education of new residents is an effective way to promote both in-house and ex-house water efficiency, through appropriate landscaping design and plant selection, and the selection of water efficient appliances and fixtures. Purchasers of lots will be provided with a copy of the DoW’s “Waterwise Rebates” brochure and the Water Corporation’s “Waterwise Ways” brochure to encourage residents to adopt water-efficient practices in the building and landscape design process.

3.1 Waterwise landscaping

3.1.1 Households

Front yard landscaping packages are being offered to purchasers of all new lots within the development, which will be designed to be water- and fertiliser-efficient. The landscaping will also act to slow the flow of roof runoff as it discharges to the road reserve, which will assist in the prevention of scour and erosion from lots.

3.1.2 Public open space

The Shire of Roebourne requires a soccer pitch to be built in the large Public Open Space in the centre of the Subject Area. The design and layout of the soccer pitch has not yet been completed, and irrigation and fertiliser requirements for this area will be defined as the design progresses.

3.2 Potable water use Potable water use will be minimised through the use of waterwise landscaping packages on residential lots, water-efficient irrigation systems in the POS area, and education of residents to encourage the use of waterwise appliances in houses.

The State Government’s 5 Star Plus (Stage 1) program introduced compulsory 4-star efficiency rated tap fittings, garden taps and toilets and 3-star efficiency rated showerheads as a minimum in new buildings, which will further minimise potable water use in households.

3.3 Wastewater management and potable water supply The potable water supply scheme and gravity sewer reticulation network will be operated by the Water Corporation, and will be extended to service the Subject Area from the existing development immediately to the east.


4 Stormwater management

4.1 Regional context Stormwater runoff from the Subject Area currently discharges via overland flow to Madigan Creek. Urban stormwater runoff from the adjacent subdivision – which extends from the eastern boundary of the Subject Area to Balmoral Road – also discharges to Madigan Creek via the open drains that cross the Subject Area. Figure 4.1 shows the extent of the catchment for each of the open drains crossing the site.

The land to the east of Balmoral Road drains to the north via a separate drainage network, and does not contribute flows to Madigan Creek.

Some of the existing open drains grade out to natural surface within the Subject Area. These drains will be extended as required through to the Madigan Creek reserve, and have been sized to convey stormwater runoff from the Subject Area and the upstream catchment. The remaining open drains already extend through to Madigan Creek, and these will be upgraded where necessary to ensure they have sufficient capacity to convey flow originating from both the Subject Area and the upstream catchment.

4.2 Stormwater management The Pilbara region is subject to intense rainfall associated with tropical cyclones. This, together with the high soil clay content, results in extreme flow rates generated by surface runoff during storm events.

Due to the high-intensity storm events that Karratha experiences, specific measures are required to protect property from flood damage. The points below outline the typical requirements for stormwater management in the cyclone-prone north-west of WA:

Finished levels of all lots to be above adjacent road levels.

No gutters to be installed on houses.

All roof runoff to be directed onto roads by grading finished lot levels from back-to-front.

All roads to be graded to convey runoff towards open drains.

To accommodate the high stormwater flows and protect houses from flood damage, individual lots in the Subject Area will be set above road pavement levels, and graded with a fall of approximately 100mm from rear-to-front boundaries to direct stormwater towards adjacent roadways. The roads will in turn convey the runoff via open gutter flow to the open drains which discharge into Madigan Creek. With the exception of large box culverts at road crossings over the open drains, piped drainage systems are not provided because they would not have sufficient capacity to convey the required flows.

Figures 4.2 & 4.3 show design earthworks levels and flow paths throughout the development.

4.3 Flood management Roads and lots through the Subject Area will be graded to direct surface runoff towards the open drains that cross the site or to the Madigan Creek reserve directly.


JDA Consultant Hydrologists have recently completed a Coastal Vulnerability Study for Karratha, which forecasts the impact of climate change on sea levels along the Karratha coastline. JDA has recommended that the 100-year flood levels in the Madigan Creek flood study be increased by 100mm to account for the forecast impact of climate change on sea levels.

The drainage reserves will be sized to contain runoff from events up to 100-year ARI. Fill levels across the Subject Area will be sufficient to ensure that habitable floor levels are at least 0.5m above the 100-year ARI flood levels.

The open drains have been designed to achieve the following:

Peak velocity in all open drains is less than 2m/s.

Depth of flow for events up to 20 year ARI is less than 1.0m.

Flow from all events up to 100 year ARI is contained within the drainage reserves, except in isolated areas where the flows overtop the road crossings.

Long sections of the open drainage channels have been included as Figure 4.4.

Towards the northern end of the site, the finished levels are controlled by sewer catchment planning, with minimum lot levels dictated by the sewer pump station emergency overflow arrangement on Kingfisher Way to the east of the Subject Area. To ensure that the pump station’s emergency overflow system functions correctly, the minimum lot levels at the northern end of the site are up to 1.9m above the 100-year ARI flood level in the adjacent Madigan Creek.

4.4 Surface water quality The open drains crossing the site will be vegetated with grasses, which will help stabilise the drainage channels and assist in trapping sediment in stormwater runoff. Specific species will be determined during the landscape design process, and will consider the recommended species in the Shire of Roebourne’s Stormwater Design Guidelines for Residential Developments.

4.5 Nuisance insect management The stormwater drainage system through the development has been designed to ensure that there are no trapped low points within the development for water to pond in. The open drains crossing the Subject Area are graded towards the Madigan Creek reserve, and will not hold stormwater runoff. This will ensure that there are no areas which water can pond for extended periods, creating habitats for mosquitoes and other nuisance insects.


5 Implementation

5.1 Implementation plan Roles and responsibilities for the management and maintenance of the subdivision are outlined in Table 5.1 below.

Table 5.1- Implementation roles and responsibilities

Item Responsibility for implementation

Initial maintenance (two years from PC unless

otherwise noted)

Long-tern maintenance

Landscaping packages

Developer Residents Residents

Waterwise information

Developer to provide educational information, residents to implement.

Residents Residents

POS & drainage infrastructure

Developer Developer Council

Sediment control

Developer Developer

Council

5.2 Managing Subdivision Works A Construction Environment Management Plan has been submitted to the Shire of Roebourne and will be implemented during civil construction works.


6 Compliance with UWMP Guidelines checklist

UWMP Item Deliverable

Summary

Development of design elements and compliance with design objectives

Table 1: Design elements and compliance

§ 1.2

Key design requirements for detailed design – critical control points and elements

Table 2: Design requirements for critical control points

§ 1.2

Planning approval

Location plan, adjoining lots, key landscape features and roads, local water management strategy

Location plan Fig 1.1

Structure plan, zoning and land use Site context plan Fig 1.1

Subdivision plan and/or approval Subdivision layout plan (OR a combination of the above)

Fig 1.1

Design objectives

Agreed design objectives and demonstration of compliance § 1.2

Site characteristics

Existing information and more detailed assessments (monitoring) of the site; explanation of how the site characteristics affect the design

§ 2

Site conditions – existing topography/contours, aerial photo underlay, major physical features

Site condition plan Fig 2.1

Geotechnical – topography, test pit locations, soil zones and descriptions, site classification zones, proposed earthworks and approximate finished contour levels

Geotechnical plan Fig 2.2

Environmental – sensitive or significant vegetation areas, wetlands and buffers, waterways and buffers, contaminated sites

Environmental plan, plus supporting data where appropriate

N / A

Surface water – topography, 100-year floodways and flood-fringe areas, 100-year proposed flow paths, water quality of flows entering and leaving (if applicable)

Surface water plan App A

Groundwater – topography, test bore locations, groundwater pre- and post-development, water quality, groundwater variation hydrograph

Groundwater plan, plus details of groundwater monitoring and testing

N / A

Landscape – proposed public open spaces, water source, bore(s), lake details (if applicable), approx. watering requirements and water balance, indicative irrigation schedule, demonstrate compliance with Interim position statement: Constructed lakes (if applicable)

Landscape plan § 3.1.2


Water sustainability initiatives

Water supply and efficiency measures § 3

Fit-for-purpose strategy and agreed actions; if non-potable supply, support with water balance

Alternative supply scheme and plan

N/A

Wastewater management § 3.3

Stormwater and groundwater management

Flood protection – peak flow rates, top water levels at control points, 100-year flow paths – floodways and flood-fringe zones and/or along roads and reserves, 100-year inundation areas and volumes

100-year flood plan

Long-section of critical points

Fig 4.1 - 4.4

Stormwater management system – storage areas, flows and hydraulic grade lines for both major and minor events including controlling inverts (critical control points); locations and arrangements for agreed structural and non-structural management practices and treatment trains, supported by sizing criteria, areas of inundation, flow paths and cross-sections, show integration with landscaping

1-year event plan

5-year event plan

Typical cross-sections

N / A

Post-development groundwater levels and fill requirements (including existing and final surface levels), outlet controls, and any subsoils (showing drawdown/effects near sensitive environments); describe modelling assumptions

Groundwater / subsoil plan

Typical cross-section (max and minimum)

N / A

Actions to address acid sulphate soils or contamination N / A

Protection of waterways (and their buffers), remnant vegetation and ecological linkages

N / A

Management of disease vectors and nuisance insects § 4.5

Other issues

Any other issues as explained in Table 2

Managing subdivision works

Management of construction activities including dewatering, acid sulphate soils, constructed best-management practices, and dust, sediment erosion control – timing and possible staging

§ 5.2

Monitoring program

Sampling and assessment plan including duration and arrangements for ongoing actions

N / A

Implementation plan

Roles, responsibilities, funding for implementation § 5.1

Agreed maintenance arrangements § 5.1

Assessment and review § 5.1


7 REFERENCES West Australian Planning Commission (2008), Better Urban Water Management

Department of Water (2004-2007), Stormwater Management Manual for Western Australia

Department of Water (2008), Urban Water Management Plans – guidelines for preparing plans and complying with subdivision conditions

Douglas Partners (2008), Report on Geotechnical Investigation – Proposed residential development, Lot 517 Dampier Road, Nickol West, Karratha, WA

Government of Western Australia (2007), State Water Plan

JDA Consultant Hydrologists (2010), Madigan Creek Flood Study, Karratha

JDA Consultant Hydrologists (2011), Coastal Vulnerability Study, Karratha

Shire of Roebourne (June 2011) Stormwater Design Guidelines for Residential Developments

The Civil Group | Pindan – Nickol West UWMP | Appendix A

Figures

STAGE 1

STAGE 2

STAGE 1

WOO

DSWAL

LOW B

E ND

KING

FISH

ER W

AY

STAGE 3

LEGEND

DRAIN RESERVE

GROUP HOUSING

P.O.S

STAGE BOUNDARY

SUBJECT BOUNDARY

STAGE 3

DAMPIER HIGHWAY

RANKIN ROAD

WEDGETAIL EAGLE AVENUE

SUBDIVISION LAYOUT AND STAGINGFIGURE 1.1

TITLECLIENT

PINDAN - NICKOL WEST UWMPOTAN KARRATHA

TP26

TP17

TP30

TP18

TP27

TP8

TP7

TP6

TP3

TP1

TEST PIT LOCATION

SUBJECT AREA

LEGEND


ROAD

5

WOO

DSWA L

LOW B

END

SANDPIPER TURN

SAND

PIPE

R TU

RN

FANTAIL BEND

BROLGA MEANDERROAD 8

ROAD

8

BROL

GA M

EAND

ER

FANT

AIL

BEND

ROAD 7

ROAD

7

KOOKABURRA PARKWAY

RIDGE ELBOW

KING

FISH

ER WAY

TATT

LER

ROUT

E

FALC

ONPA

RADE

RANKIN ROAD

GOSH

AWK

CIRC

LE

ROAD 6

ROAD 3

ROAD

4

ROAD

ROAD 3

ROAD 2

ROAD 2

ROAD 2

ROAD

5

K ING

FIS H

ER WAYEXTENT OF GILGAI SOILS

TP19

TP16TP15

TP11

TP10

TP12

TP9

TP4

TP2

TP21

TP14

TP5

TP13

TP22

TP23

TP24

TP29TP28TP20

TP25

ROAD 3

8

GEOTECH AND TEST PIT LOCATIONSFIGURE 2.2

TITLECLIENT


KING

FISH

ER W

AY

WOO

DSWAL

LOW

BE

ND

DAMPIER HIGHWAY

RANKIN ROAD


SAND

PIPE

R TU

RN

FAL C

ON

P

ARAD

E

BALM

ORAL

ROA

D

DRAINAGE CATCHMENTSFIGURE 4.1

TITLECLIENT


LEGENDSUBJECT AREA

10.27 9.90 10.27 9.87

9.99

10.77

9.96

9.66

11.28

11.10

11.33

10.9310.45

11.83

12.15

11.98

12.75

10.60

10.6710.90

10.60

10.6010.95

11.18

9.66

10.82

11.70

10.55

11.3610.95

11.1011.26

11.60

11.60

11.75

11.13

11.4911.60

12.10

11.72

11.56

11.90

OVERLAND FLOW PATH

10.27 DESIGN EARTHWORKS LEVEL

IL 9.30 IL 9.55 IL 9.60 IL 9.70 IL 9.75

IL 8.90IL 8.85IL 8.80IL 8.35 IL 8.95 IL 9.00

11.25

11.50

IL 10.6IL 10.7

P.O.S

DRAIN RESERVE

DESIGN EARTHWORKS LEVELS AND OVERLAND FLOW PATHSFIGURE 4.2

TITLECLIENT


11.85

11.79

13.03

12.15

11.98

12.75

13.42

14.36 14.17

12.65

12.45

13.55

13.26

13.97

14.67

14.05

14.04

13.93

11.60LEGEND

SUBJECT AREA

OVERLAND FLOW PATH

10.27 DESIGN EARTHWORKS LEVEL

13.76

IL 13.6 IL 13.8

IL 10.3

IL 10.6IL 10.7

DRAIN RESERVE

IL 12.4IL 12.2

DESIGN EARTHWORKS LEVELS AND OVERLAND FLOW PATHSFIGURE 4.3

TITLECLIENT


60.00

9.05

76.28

9.00

110.00

8.97

145.15

8.95

162.73

8.90

200.00

8.87

230.00

8.85

245.80

8.80

280.00

8.74

360.00

8.60

410.00

8.52

500.00

8.36

CHAINAGE

OPEN DRAIN INVERT

LONGITUDINAL SECTION 1

10.44

10.19

10.34

10.24

9.89

10.13

9.72

ROAD

FIVE

KING

FISH

ER W

AY

GOSH

AWK

CIRC

L E

RANKIN ROAD F.S.L.

ROAD

TWO

0.00

10.99

30.00

9.80

67.78

9.75

88.42

9.70

120.00

9.68

153.86

9.60

171.4

49.55

200.00

9.49

250.00

9.36

CHAINAGE


OPEN DRAIN INVERT

ROAD THREE F.S.L.

11.17

11.32

10.89

10.49

10.13

RANKIN ROAD

OPEN DRAIN

ROAD THREE

WEDGETAIL EAGLE AVENUEOPEN D

RAIN

OPEN DRAIN

ROAD

FIVE

ROAD

FOU

R

1

2

3

4OPEN DRAIN

0.00

10.98

20.00

10.92

60.00

10.79

91.35

10.70

109.63

10.60

150.00

10.59

200.00

10.40

250.00

10.26


12.66

12.73

12.53

11.88

11.63

11.38

ROAD

FIVE

0.00

13.04

30.00

12.28

66.93

12.20

85.18

100.00


13.80

12.10

ROAD

EIGHT

ROAD

EIGHT

TITLECLIENT

PINDAN - NICKOL WEST UWMPOPEN DRAIN LONGITUDINAL SECTIONSOTAN KARRATHA PTY LTD

FIGURE 4.4

ROAD

FIVE

OPEN DRAIN

OPEN DRAIN

ROAD TWO

DAMPIER HIGHWAY

BROL

GA M

EAND

ERWOO

DSWAL

LOW B

END

20 YEAR FLOOD LEVEL

100 YEAR FLOOD LEVEL

8.76

8.76

9.50

9.64

9.63

9.89

9.94

9.73

10.01

9.81

10.14

9.90

10.33

10.00

KING

FIS H

ER WAY

KING

FIS H

ER WAY

ROAD

FIVE

ROAD

FOU

R

ROAD

FIVE

5

20 YEAR FLOOD LEVEL


10.21

10.31

10.32

10.49

10.42

10.57

10.56

10.80

10.64

10.85

0.00

13.87

13.99

70.00

13.78

100.00

13.60

14.23

14.34

14.25

CHAINAGE

OPEN DRAIN INVERT

WEDGETAIL F.S.L.

20 YEAR FLOOD LEVEL

100 YEAR FL00D LEVEL

11.01

11.26

11.75

12.13

11.86

12.19

11.45

11.60

CHAINAGE

OPEN DRAIN INVERT

F.S.L. LOT 706 + 727

20 YEAR FLOOD LEVEL


13.01

13.30

12.99

13.29

12.66

12.85

CHAINAGE

OPEN DRAIN INVERT

ROAD EIGHT F.S.L.

20 YEAR FLOOD LEVEL


14.18

14.25

13.98

14.03


60.00

GOSH

AWK

CIRCL

E

OPEN DRAIN

LEGENDOPEN DRAIN INVERT LEVELS

ADJACENT FINISHED SURFACE LEVELS

100YR FLOOD LEVEL

20YR FLOOD LEVEL

BOX CULVERTS

5x450x1200 RCB

706727

5x450x1200 RCB5x450x1200 RCB

4x450x1200 RCB 4x450x1200 RCB

6x450x1200 RCB

2x450x1200 RCB

The Civil Group | Pindan – Nickol West UWMP | Appendix A

Appendix A – Madigan Creek Flood Study extract

9.5

7.21

7.59

8.05

8.68

9.08

9.93

12.6

13.1

16.7

10.37

10.72

11.04

11.48

11.88

12.21

13.57

14.44

14.67

15.15

15.49

15.79

16.21

17.24

17.73

18.33

18.93

19.53

20.39

8

9

6

7

5

26

23

25

24

22

16

19

20

18

15

17

11

10

27

14

12

28

29

21

31

30

4

3433

13

35

36

32

37

38

4039

44

42

41

46

43

45

4850

47 49

5254

51

53

30

11

35

30

42

15

10

28

9

23

14

9

29

10

98

37

32

10

32

9

7

22

46

10

44

8

3427

7

8

22

7

9

10

24

8

40

26

26

15

7

13

16

31

25

14

15

16

28

6

10

24

35

31

30

7

149

24

9

7

24

22

13

4

17

33

8

29

31

7

12

32

8

48

29

33

36

31

27

16

28

3235

30

8

26

50

9

9

23

27

13

15

16

8

14

8

13

7

9

29

26

38

10

8

23

30

4

26

21

12

27

10

9

13

14

9

37

8

21

9

21

52

39

28

33

4

34

32

16

25

37

25

11

7

8

10

14 13

27

9

9

25

17

29

28

36

24

31

15

27

13

6

7.14

7.45

7.96

8.63

8.99

9.43

9.86

12.5

10.31

10.68

10.99

11.42

11.83

12.11

13.08

13.57

14.43

14.49

14.77

15.31

15.76

16.14

16.62

17.18

17.71

18.34

18.94

19.53

20.39

0 200 400 600 800Meters

Study Area

Proposed Developments

Pre Development 100yr ARI Floodplain

Post Development 100yr ARI Floodplain

Pre Development 100yr ARI Flood Levels

Post Development 100yr ARI Flood Levels

Job No. J4755

Madigan Creek Flood Study

Figure 16: Pre and Post-Development 100 year ARI Floodplains

LandCorp

Data Source: Karratha Aerial Photo (Landgate, 2008)

© COPYRIGHT JIM DAVIES & ASSOCIATES PTY. LTD. 2010

±

Scale 1:15,000

Dampier Highway

Madigan Creek

Pre-Development Post-Development

PINDAN PTY LTD Nickol West Karratha · The Civil Group WA Pty Ltd (thecivilgroup) and the Client...

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