stage 2 construction soil and water management sub plan€¦ · soil and water management sub plan...

Soil and Water Management Sub Plan

Seahampton to Kurri Kurri Section

HEA-PL-GL-SWP-001-00-03

Rev Date Prepared by Reviewed by Approved by Remarks

0 29th

March

2010

M Frankcombe T Doczy P Chatburn

1 13th

May

2010

M Frankcombe T Doczy P Chatburn Includes RTA

comments

2 10th

June

2010

J. Wright H. Chemney P. Chatburn Includes RTA, DI&I,

NSW OoW,

Councils & EMR

review comments

3 14th

July

2010

E. Woodward H. Chemney P. Chatburn Includes DoP

Comments

Hunter Expressway Alliance

SOIL AND WATER MANAGEMENT SUB PLAN

HEA-PL-GL-SWP-001-00-03 Page 2

DOCUMENT CONTROL

Document Type: Environmental Management Sub Plan Document No/Ref:

HEA-PL-GL-SWP-001-00-02

Title: Soil and Water Management Sub Plan

General

Description:

Provides management measures and mitigation strategies to be undertaken to mitigate the

potential impacts as they relate to pre-construction, construction, post-construction and

some elements (design) of the operational phase of the project.

Management of soil & water issues during the operational phase of the project will be

undertaken by RTA

Document Path: S:\HEA\01 Environment\01_08 CEMP\Volume 2\Soil & Water\For Final Submission\HEA-

PL-GL-SWP-001-00-02.doc

Approval Name Position Signed/Approved Date

Document

Editor / Author

John Wright Soil Conservationist /

Scientist

Review Howard Chemney Environment Manager

- Design

Alliance Project

Director

Peter Chatburn Project Director




TABLE OF CONTENTS

1 INTRODUCTION ...........................................................................................................................5

1.1 Purpose and Scope .......................................................................................................................5

1.2 Objectives ......................................................................................................................................7

1.3 Water treatment methodology .......................................................................................................8

1.4 Environmental Constraints.............................................................................................................8

1.4.1 Climatic Conditions ................................................................................................................8

1.5 Rainfall Records and Patterns .......................................................................................................9

1.6 Rainfall Erosivity Factor .................................................................................................................9

1.6.1 Soil Types ........................................................................................................................... 10

1.7 Acid Sulphate Soils ..................................................................................................................... 12

1.8 Endangered Ecological Communities ......................................................................................... 12

1.9 Existing Waterways and/or Drainage Lines ................................................................................ 13

2 LEGISLATIVE REQUIREMENTS AND GUIDELINES .............................................................. 14

3 LIMITATIONS, CONSTRAINTS AND OPPORTUNITIES ......................................................... 16

4 PERFORMANCE CRITERIA...................................................................................................... 18

5 POTENTIAL SOURCES OF POLLUTANTS ............................................................................. 19

6 MANAGEMENT AND MITIGATION MEASURES ..................................................................... 20

6.1 Progressive erosion and sediment control plans ........................................................................ 20

6.2 Work Procedures ........................................................................................................................ 21

6.3 Environmental Construction Method Statement ......................................................................... 21

6.4 Training ....................................................................................................................................... 22

6.5 Soil Conservationist .................................................................................................................... 23

6.6 General Management and Mitigation Measures ........................................................................ 24

6.7 Design ......................................................................................................................................... 27

6.8 Access and Site Set Up .............................................................................................................. 31

6.9 Clearing....................................................................................................................................... 32

6.10 Earthworks .................................................................................................................................. 33

6.11 Drainage and Bridgeworks ......................................................................................................... 36

6.12 Paving and Vehicle Movement ................................................................................................... 40

6.13 Rehabilitation and Landscaping ................................................................................................. 42

7 INSPECTIONS ........................................................................................................................... 44

8 MONITORING AND REPORTING ............................................................................................. 46

9 CORRECTIVE ACTION ............................................................................................................. 48




LIST OF TABLES

Table 1.1: Requirements of MCoA and where these have been addressed in the Sub Plan /other

documentation ......................................................................................................................................... 5

Table 1.2: Summary of Cessnock rainfall records................................................................................... 9

Table 1.3: Monthly % and Annual Rainfall Erosivity (R-factor) values for Newcastle City .................... 10

Table 1.4: Soil Types along the HEA alignment .................................................................................... 10

Table 2.1 : Relevant Legislation ............................................................................................................ 14

Table 3.1: Site constraints and opportunities ........................................................................................ 16

Table 5.1: Summary of potential sources of water pollution ................................................................. 19

Table 6.1 Management and Mitigation Measures ................................................................................ 24

Table 7.1: Inspection Requirements ...................................................................................................... 44

Table 8.1: Monitoring and Reporting Requirements ............................................................................. 46

APPENDICES

APPENDIX A – WATER QUALITY MONITORING WORK PROCEDURE

APPENDIX B – DEWATERING PROCEDURE

APPENDIX C – PROPOSED SEDIMENT BASINS

APPENDIX D – ACID SULFATE SOIL MANAGEMENT STRATEGY

APPENDIX E – AFFLUX PRELIMINARY IMPACT ASSESSMENT

APPENDIX F – LOCATION OF DRAINAGE STRICTURES, WATERWAYS AND WATER QUALITY

MONITORING LOCATIONS




1 INTRODUCTION

1.1 Purpose and Scope

This Soil and Water Management Sub Plan forms part of the Construction Environmental Management Plan (CEMP) for the Hunter Expressway Alliance project (HEA).

This Sub Plan has been developed in response to condition numbers 87, 88, 89 and 93 of the Minister of Planning’s Conditions of Approval (MCoA) for the Hunter Expressway.

MCoA 87, 88, 89 and 93 stipulate the content of the Sub Plan although other MCoA’s also detail with soil and water issues, Refer to Table 1.1 below for details on the requirements of the MCoA and where these have been addressed in the Sub Plan or other documentation.

Table 1.1: Requirements of MCoA and where these have been addressed in the Sub Plan /other documentation

Requirement Where addressed

87. A detailed Soil and Water Management Sub Plan shall be prepared

in consultation with the DLWC, NSW Fisheries, and relevant Councils.

The Sub Plan shall be prepared in accordance with the Department of

Housing’s guideline Managing Urban Stormwater - Soils and Construction

and where appropriate, DLWC’s Constructed Wetlands Manual. The Sub

Plan shall be prepared prior to construction or operation. The section of

the Sub Plan dealing with construction impacts shall be submitted to the

EPA when applying for an Environment Protection Licence for the

construction phase.

This Sub Plan

88 The Soil and Water Management Sub Plan shall contain, but not be

limited to:

i. management of stormwater from the development on the quality of

surface and groundwater;

s.5 and s.6

ii. details of short and long term measures to be employed to minimise soil

erosion and the discharge of sediment to land and/or waters including the

locations of suitably sized sedimentation basins;

s.6 and App B and App. C

iii. management of the impacts of the development on watercourse

crossings including Wallis/Surveyors Creeks, South Maitland

Railway/Swamp Creek, Bishops Creek, and Black Creek;

S. 6.

Swamp Creek, Bishops Creek and

Black Creek are not impacted by the

Hunter Expressway Alliance and are

therefore not addressed in this

SWMP. Any impacts on these creeks

will be detailed in the Design &

Construction project documentation

iv. management of the impacts of Wallis/Surveyors Creeks, South

Maitland Railway/Swamp Creek, Bishops Creek, and Black Creek on the

development;

S. 6.

Swamp Creek, Bishops Creek and

Black Creek are not impacted by the

Hunter Expressway Alliance and are

therefore not addressed in this

SWMP. Any impacts on these creeks

will be detailed in the Design &





Construction project documentation

v. identification of all potential sources of water pollution and a detailed

description of the remedial action to be taken or management systems to

be implemented to minimise discharges of these pollutants from all

sources within the subject site;

s.5 and s.6

App B

vi. detailed description of water quality monitoring to be undertaken during

the pre-construction, construction and operation stages of the proposal

including identification of locations where monitoring would be carried out;

s.7 , S. 8 and App A

vii. contingency plans for fuel and other spills. s.5. s.6 and ‘Refuelling and Liquid

Storage Protocol’ (HEA-WP-GL-

ENV-03-00-00) located in both the

Construction Environmental

Management Plan (HEA-PL-GL-

EMP-001-00-02) and the Hazard and

Risk Management Sub Plan (HEA-

PL-GL-HRP-001-00-02)

viii. a program for reporting on the effectiveness of the sediment and

erosion control system against performance goals.

Reporting shall be undertaken via

standard reporting requirements of

six monthly Construction Compliance

Reports and monthly Environmental

Performance Reports.

89. The Soil and Water Management Sub Plan shall also incorporate

detailed erosion and sedimentation controls including a strategy to

manage the extent of exposed ground surface during construction and

progressive site rehabilitation requirements (in accordance with Conditions

of Approval Nos. 97 and 114). The Sub Plan shall be prepared to the

satisfaction of DLWC and in consultation with the EPA and NSW Fisheries

and sufficient to address the technical requirements

s.6 Landscape Management Plan

(HEA-PL-GL-LP-001-00-00) and

Flora and Fauna Plan (HEA-PL-GL-

FFP-001-00-05)

90. The DLWC, or other appropriately qualified soil conservationist,

shall be consulted on a regular basis to undertake inspections of

temporary and permanent erosion and sedimentation control devices to

ensure that the most appropriate controls are being implemented and that

they are being maintained in an efficient condition at all times and meet

the requirements of any relevant approval/licence condition(s).

Requirement included in s 6.5 –

Table 6.1 and s7.

91. All water collected during construction which is likely to be

contaminated, shall be tested, treated, handled and disposed of so that it

does not pollute waters.

Requirement included in s 6.5 –

Table 6.1 and general principle

applied throughout document

92. Sediment basin(s) must be designed (stability, location, type, and

size), constructed, operated and maintained in accordance with the

guideline Managing Urban Stormwater - Soils and Construction, 3rd

edition, 1998, or its latest edition, produced by the NSW Department of

Housing unless otherwise approved by the EPA.

Sediment basins designed in

accordance with the “Blue Book”

Volume 2d and requirement reflected

in s 6.6-Table 6.1

93. The Soil and Water Management Sub Plan shall identify mitigation

measures proposed to be taken to address any:

i. afflux impacts from the roadway or structures associated with the

App E





proposal eg. the proposed Wallis/Surveyors Creek crossing and impacts

upstream in the Buchanan area; and

ii. adverse impacts from the proposal as a result of losses to the Hunter

River floodplain storage areas for flood events above and including the 1%

Annual Exceedence Probability Event eg. the Wentworth and Dagworth

Swamps;

94. All stormwater drainage, erosion, sedimentation and water pollution

control systems and facilities of the proposal shall be located, designed,

constructed operated and maintained to meet the requirements of the

relevant authorities including the EPA and the DLWC. All facilities

including wetland filters, grass filter strips, gross pollutant traps and

sedimentation basins shall be inspected regularly and maintained in a

functional condition for the life of the project. Construction stage water

quality structures shall be maintained for a minimum of six months after

commissioning of the proposal or until revegetation has provided

groundcover to at least 70% of the exposed surface.

Requirements included in Table 6.1

95. The Proponent shall provide appropriate detention systems for

containment of spills and materials arising from accidents that are

consistent with the Proponent’s Code of Practice for Water Management –

Road Development and Management in consultation with the EPA.

Requirements included in s6.6-Table

6.1

96. The Proponent shall identify the most appropriate measures to

safeguard and/or mitigate impacts on the groundwater, or impacts arising

from any groundwater dewatering operations, in consultation with the

DLWC, prior to the commencement of construction. Measures may

include:

i. evaluation of aquifer characteristics including conductivity and salinity;

ii. identification of suitable sites for the disposal of saline groundwater from

dewatering activities; and

iii. installation of monitoring bores.

A groundwater monitoring and

management plan is currently being

developed for the project in

consultation with NSW OoW to

address the requirements of CoA 96.

This Sub Plan provides practical measures that will be implemented to minimise any detrimental impact on the surrounding environment resulting from soil erosion, sediment transport, and chemical spills during pre-construction, construction and post-construction phases of the project. Management of soil & water issues during the operational phase of the project will be undertaken by RTA

While this Sub Plan provides overall guidance and direction for the management of soil and water related issues a number of Work Method Statements and Environmental Construction Method Statements will be prepared to be used in site specific situations.

Management of soil & water issues during the operational phase of the project will be undertaken by RTA

1.2 Objectives

The objectives of the Soil and Water Management Sub Plan are to:




• Minimise the impact of erosion and sedimentation from construction activities

associated with the Hunter Expressway;

• Ensure all sediment and erosion controls are implemented on site in accordance with

best practice environmental management as outlined in Department of Environment,

Climate Change and Water NSW“ Managing Urban Stormwater - Soils and

Construction, Volume 2D Main road construction” and the RTA’s “Guidelines for the

Control of Erosion and Sedimentation in Roadworks”;

• Ensure no accidental spills into nearby watercourses;

• Ensure necessary controls are implemented in key sensitive sites, such as DECCW

estate and EEC’s;

• Provide an organised, integrated systematic approach to effectively address erosion

and sedimentation and other water pollution issues during the project; and

• Provide staff with an increased level of understanding and awareness and assign

accountability of soil and water management issues.

1.3 Water treatment methodology

The aim of water quality treatment for the Hunter Expressway is to ensure that water quality objectives are achieved with minimum clearing and disruption to the existing environment and that natural habitats can be maintained in order to allow for minimum disruption to existing ecosystems.

Operational water quality treatment measures have been incorporated into the longitudinal drainage design. The preferred approach to operational water quality includes using a combination of treatment methods in the form of a treatment train. Stormwater treatment measures may include operational basins, buffer zones, vegetated swales, natural and constructed wetlands. The combination of treatment measures used will vary dependent on the receiving environment.

The receiving environment may vary between a watercourse or outlet located in an Endangered Ecological Community (EEC), non EEC area, Kurri Kurri Sand Swamp Wetlands (KSSW) or open space areas.

Basins will be be located in order to minimise environmental impacts including the impact of clearing of EEC and non EEC areas and KSSW areas. Therefore, wherever possible basins have been located out of environmentally sensitive areas.

In locations where there are environmental or corridor constraints the use of reduced or alternative solutions will be considered in order to minimise clearing impacts on sensitive areas. All options available shall be consulted on with the relevant Authorities.

It is intended to provide some level of treatment to all stormwater runoff from the main carriageway and F3 and Buchanan interchanges.

1.4 Environmental Constraints

1.4.1 Climatic Conditions

The Hunter Expressway extends approximately west to east over the Sugarloaf range onto the old Hunter river flood plain. The quality and reliability of climatic data for this area is dependent on the position of the weather stations to the Hunter Expressway construction site and length of




time that the records have been collected over time.

1.5 Rainfall Records and Patterns

The climatic data records of Cessnock (Nulkaba) have been chosen to reflect the potential climatic conditions for the project site due to its proximity to the overall site and extent of available data (43 years). A summary of rainfall records is provided in Table 1.2 below.

Table 1.2: Summary of Cessnock rainfall records

Cessnock rainfall records for past 43 years (mm)

Summer - Autumn Winter - Spring

Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Year

Mean 70.2 87.3 102.1 87.0 57.0 53.3 57.3 32.0 37.4 43.5 58.4 69.7 754.3mm

Rain days

Mean 9.5 10.4 10.4 10.7 8.8 8.7 7.3 7.7 7.6 9.5 10.9 9.5 110.4

days

Note the table has been divided into Summer/Autumn & Winter/Spring

Summer /autumn period is the dominant rainfall period and is more reliable due to the dominance of easterly trade winds at this time of the year. It should be noted that summer thunderstorms (Southerly Busters) have an important bearing on rainfall intensity in this area. Their impact will be greater on the easterly side of the Sugarloaf Range affecting the Alliance component of the project more. Numerous storms are reasonably expected to cross over the Sugarloaf range at times impacting on the Alliance component of the project.

Winter /spring rainfall generally occurs during late winter and early spring and is less reliable.

The summer- autumn period has the highest probability for erosion during the thunderstorm season, compounded when areas are left bare of vegetation for prolonged periods.

1.6 Rainfall Erosivity Factor

The Rainfall Erosivity factor is a measure of the ability of “rainfall to cause erosion and is used in determining total potential soil runoff”, (referred as “R” in the Revised Universal Soil Loss Equitation RUSLE). The Rainfall Erosivity factor is used to determine the soil loss in tonnes per hectare over one year, and is used in calculations in relations in sizing sediment basins.

The project has a Rainfall Erosivity factor of 2,500 SI, this is approximately the mid range for the state of New South Wales, as written in the Blue Book.

Newcastle City is the closest location with detailed R-factor data and is detailed below in Table 1.3 below. Newcastle City is located approximately 17.4 Km from the eastern end of the project.




Table 1.3: Monthly % and Annual Rainfall Erosivity (R-factor) values for Newcastle City

Monthly % & Annual Rainfall Erosivity (R-factor) values

Dec Jan Feb Mar Apr May

Jun Jul Aug Sep Oct Nov Yearly

R-value

% 8.8 9.9 12.9 10.7 8.9 7.9 6.0 4.7 5.1 5.6 5.8 8.8 3890

R-Values 342 385 501 536 416 345 307 233 183 198 218 225 3980

Ref IECA- Best Practice Erosion & Sediment control table B6 Nov 2008

This data along with rainfall patterns reinforces that the greatest erosion risk due to storm activity is during the summer/autumn season.

1.6.1 Soil Types

Soil types have been compiled from NSW Department of Land and Water Conservation Soil Landscape Sheets for Newcastle at a 1:100,000 scale and Singleton at a 1:250,000 scale. Soil types have been described in Table 1.4 below.

Table 1.4: Soil Types along the HEA alignment

Ch. Description Soil type Topography Soil characteristics Revegetation

implications

0 – 2600

Newcastle

interchange

to end of

viaducts

Killingworth

Undulating to

rolling hills on

sediments of

Newcastle

Coal

measures,

slopes 3 to

20%, with

steep gullies

and rocky

outcrops.

� Highly erodable podzolic

soils that are sodic and

dispersive (mainly subsoils),

especially when the shallow

topsoil is removed;

� High rates of runoff – soil

hydrologic group C/D;

� Topsoil classified as Fine

type, K-factor 0.027;

� Subsoil – bleached hard

setting sandy clay loam as a

Dispersive type, K-factor

0.036; and

� Subsoil - yellowish clay as a

Dispersive type, K-factor

0.036.

Revegetation on

these soils will

be problematic

due to their very

strong acidity,

low fertility and

hard setting

surfaces.

2600 –

3850

Blue Gum

creek through

to Skyline

Ridge

Stockrington Extremely

steep slopes

15 to 20%

slopes.

� Earthy loams (sandy to clay

sandy loams) sitting on

massive conglomerate and

coal seams;

� Medium rates of runoff –soil

hydrologic group B;

� Topsoil dark sandy loam,

classified as Fine type; K-

factor 0.015;

Revegetation on

these soils will

be problematic

due to its strong

acidity, low

fertility and hard

setting surfaces.





implications

� Subsoil – bleached gravelly

sandy clay loam Cause/Fine

type; K-factor 0.039; and

� Subsoil – bleached gravelly

sandy clay Dispersion type;

K-factor 0.039.

3850 –

7000 Killingworth See above. � See above See above

7000 –

10000

Buchanan

interchange

Beresfield Undulating to

flat country

with slopes 3

to 15% though

in this area

mainly on the

low side.

� Soils are deep with sandy to

silty topsoil on top of highly

erodible subsoils that have

a high foundation hazard

due to shrink- swell potential

as well as areas of

dispersive sodic soils;

� Medium to high rates of

runoff- soil hydrological

group C;

� Topsoil dark loam, classified

as Dispersive type; K-factor

0.028;

� Topsoil hard setting

yellowish brown sandy loam

topsoil classified as a

Dispersive type; K-factor

0.048;

� Subsoil mottled clay

classified as Fine type; K-

factor 0.018; and

� Subsoil dull yellow orange

puggy silty clay classified as

Dispersive type; K-factor

0.048 highly erodible.

Revegetation on

these soils will

be problematic

one the topsoil is

lost due to their

very strong

acidity, low

fertility, potential

high soil salinity

and hard setting

surfaces.

10000 –

11500

Buchanan

floodplain Wallis Creek

Old hunter

river flood

plain with

slopes less

than 3%

� Soils are characterised by

deep alluvial soils made up

of either brownish to black

clay loam topsoils rich in

organic matter loose sandy

loam sitting on a clayey

sandy subsoil;


runoff –soil hydrologic group

B/C;

� Topsoil dark

greasy(organic) clay loam ,

classified as Fine K-factor

0.029;

Unknown





implications

� Topsoil brown loose sandy

loam, classified as Fine; K-

factor 0.042; and

� Subsoil pale loose clayey

sand to loamy sand.

Classified as Fine; K-factor

0.032.

11500 –

13200

Averys Lane

to east of

Stanford

Road

Heddon Greta Gently sloping

land between

2 to 10%

slopes.

� Soils prone to both wind and

water erosion as they are

old shallow wind blown

sands layered over bed

rock;


runoff – soil hydrologic

grouping B/C;

� Topsoil dark loose loamy

sand classified as Fine, K-

factor 0.016 (high wind

erosion potential);

� Topsoil greyish loose to

clayey sand classified as

fine, K- factor 0.031;

� Subsoil yellowish mottled

sandy clay, classified as

Fine; K-factor 0.024; and

� Subsoil radish mottled clay,

classified as Dispersive; K-

factor 0.026.

Revegetation on

these soils will

be problematic

one the topsoil is

lost due to their

very strong

acidity, low

fertility, potential

high soil salinity

and hard setting

surfaces.

1.7 Acid Sulphate Soils

Investigations undertaken to date indicate a low probability of acid sulphate soils being found along the Alliance section of works with only the floodplain west of the Buchanan Interchange (specifically the Wallis Creek area) having a small potential of acid sulphate soils being present or intercepted by the works.

Acid sulphate soil risk areas will be identified on Project area sensitivity mapping and details included within the relevant Environmental Construction Method Statements.

Please refer to Appendix D for the Acid Sulfate Soil Management Strategy.

1.8 Endangered Ecological Communities

The Hunter Expressway runs through a series of Endangered Ecological Communities (EEC) including:

• Coastal Plains Smooth-barked Apple Woodlands;

• Alluvial Tall Moist Forest;




• Coastal Foothill Spotted gum – Iron Bark Forest;

• Kurri Sand Swamp Woodland EEC;

• Lower Hunter Spotted Gum-Ironbark Forest EEC; and

• Hunter Lowlands Redgum Forest EEC.

The HEA allocated vegetation clearing footprint of 63ha (MCoA60) and presence of endangered ecological communities will limit available locations for erosion and sediment controls such as construction sediment basins outside the footprint of the road alignment. Alternative erosion and sediment controls will need to be implemented in some location to reduce the clearing footprint of the project.

1.9 Existing Waterways and/or Drainage Lines

Approximately 37 cross-drainage structures and 9 bridge structures (see Appendix F for details) will be constructed for the Hunter Expressway. There are five main creeks associated with the alignment:

• Minmi Creek;

• Blue Gum Creek;

• Surveyors Creek;

• Wallis Creek; and

• Fishery Creek.

There has been limited water quality monitoring to date. As to be expected due to the soil types along the alignment and existing disturbance associated with past mining activities, fire trails and motorcycle tracks, turbidity and suspended solids are elevated during periods of rainfall causing runoff.

There will be erosion and sediment controls in place at all waterways to maintain the separation of clean and dirty (site) water. All waterways will be flagged as potential sensitive areas of native flora and fauna habitat and will be appropriately managed to minimise impact on the waterways.




2 LEGISLATIVE REQUIREMENTS AND GUIDELINES

Key legislation and guidelines for soil and water are listed in Table 2.1 below.

Table 2.1 : Relevant Legislation

Relevant key legislation and

guidelines Application to project

Protection of the Environment

Operations Act 1997.

This Act provides for the control of polluting activities in NSW in order to

prevent pollution of the environment. Offences exist in relation to activities

that cause water, soil and air pollution. It is administered by the Department

of Environment, Climate Change and Water (DECCW).

The POEO Act contains a core list of activities (Scheduled Activity) that

require a licence. These are listed in Schedule 1 of the Act. Road

construction is a Scheduled Activity (35 Road Construction) and an

application for an Environmental Protection Licence will be submitted to

DECCW. Soil, water and air pollution associated with generation, handling

and disposal of waste are controlled through the CEMP and this Sub Plan.

Fisheries Management Act 1994. The Act provides a comprehensive framework for the sustainable

management of living aquatic resources.

Under the Act, a permit is required for any activity associated with main

roads that involves dredging or reclamation works, or that has the potential

to:

� Block the passage of fish (e.g. road crossings); and

� Harm marine vegetation.

Managing Urban Stormwater – Soils

and Construction Landcom 1998.

Provides guidance on erosion control measures to be implemented during

land development activities.

Managing Urban Stormwater – Soil

and Construction, Volume 2D –

Main road construction. Department

of Environment, Climate Change

and Water 2008.

Provides specific guidance on erosion and sediment control strategies for

main road construction.


and Construction, Volume 2C –

Unsealed Roads. Department of

Environment, Climate Change and

Water 2008.

Provides specific guidance on erosion and sediment control for unsealed

road which will be applied for geotechnical and construction access tracks

along the alignment.

Australia and New Zealand

Environment and Conservation

Council (ANZECC) and Agriculture

and Resource Management Council

of Australia and New Zealand.

(ARMCANZ): Australian and New

Zealand Guidelines for Fresh and

Marine Water Quality, 2000.

Provide objectives and guidelines to protect and improve water resources

and water quality. The guidelines are not mandatory. Applies to any water

that may be affected by construction activities such as sediment laden run-

off and/or chemical spills.




Relevant key legislation and

guidelines Application to project

RTA Code of Practice for Water

Management (Road Development

and Management), 1999.

Provides the principles of water management that the RTA is committed to

following in the planning, construction and maintenance works that are

carried out at various stages of a road’s life.

RTA Erosion and Sedimentation

Risk Assessment Procedure, 2006.

Provides a process to identify RTA projects with a high risk of erosion and

sediment control impact and ensures that appropriate expertise and design

is provided to mitigate the identified risks.


and Construction, Volume 2A –

Instillation of Services, Department

of Environment Climate Change and

Water, 2008

Provides specific guidelines on erosion & sedimentation control strategies

for the instillation of services




3 LIMITATIONS, CONSTRAINTS AND OPPORTUNITIES

The presence of Endangered Regional Ecosystems that need to be protected and highly erosive soils present significant challenges in achieving effective soil and water management on site. A constraints and opportunities analysis of these aspects is provided in Table 3.1 below to identify these issues and assist in the development of mitigation measures provided in section 6.

Table 3.1: Site constraints and opportunities

Issue Sub-issue Constraints Opportunities

Clearing of native

vegetation limited

to 63ha.

Insufficient room to install

sufficient number of

construction sediment basins.

Difficulties in achieving EPL

limits and protect water

quality and creek systems

from impact in locations

where it is not

possible/feasible to install

construction basins.

Use of 2 day basins and

intensive flocculation with

faster acting flocculants .

Improve source control of

erosion and sediment to limit

reliance on basins.

Rapid and progressive

stabilisation of disturbed

areas to reduce the size of

basins including providing

benches in designs to allow

the progressive stabilisation

of benches as they come

down in cuts and as they

come up in fills.

Use of temporary basins that

may be positioned partially

within the construction

footprint for use in the initial

stages of earthworks.

Install diversion/cut-off

drains to divert clean flows

away from all cleared areas

Insufficient room to install

sufficient number of

operational spill and water

quality basins.

Operational water quality

targets for the protection of

creek systems may not be

achieved. Not all creek

catchments will be able to be

protected from spills.

Prioritise operational basin

location based on spill risk.

Insufficient area to construct

basin access tracks to treat

and maintain basins.

Inability to achieve water

quality targets and maintain

basin capacity.

Use automated flocculent

dosing using the “New

Zealand” flocculent sheds or

some other means of

automated dosing to limit

access requirements (during

construction).

Improve source control of

erosion and sediment to limit




Issue Sub-issue Constraints Opportunities

reliance on basins.

Insufficient room to construct

adequate drain inlet and

outlet protection works and to

adequately protect creek

diversions from erosion.

Erosion downstream of

outlets and within creek

diversions.

Utilise bridges, arches etc to

minimise requirement for

creek diversions. Use of

natural channel design

techniques to reduce the

footprint of erosion

protection works.

Insufficient area to stockpiled

stripped site topsoil.

Topsoils stockpiles will be

higher and steeper resulting

in faster decline in the

biological viability of seeds

and soil micro fauna.

Utilise degraded fire trails for

topsoil stockpiles.

Direct place topsoil for

rehabilitation purposes.

Insufficient area to allow the

upgrade of existing fire trails

for geotechnical drilling, mine

grouting and construction

access.

Access may be limited during

periods of wet weather

resulting in construction

delays. The type of

machinery/trucks that can

use the trails may be limited

resulting in construction

delays and increased costs.

Work with NPWS to

determine fire trail upgrading

requirements/planning so

that Hunter Ex access tracks

upgrading achieves NPWS’s

needs and can be removed

from the disturbance

footprint.

Site soils. Soils are highly erosive and

dispersive.

Chemical amendment of soils

necessary to reduce erosion

risk and to allow vegetation

establishment.

Rapid and progressive

stabilisation required.

All drains with flow velocities

greater than 0.3m/s will need

to be lined.

Sediment basins and

flocculation is necessary to

achieve EPL water quality

limits.

Modification of RTA

standard specifications to

address requirements.

The use of aluminium

flocculants to improve basin

and water treatment

performance (risk

assessment of negative

effects to be clarified before

consideration) .

Dedicated trained and

experienced sediment basin

management team.

Topsoil quality and volume. Topsoil likely to be of poor

quality for revegetation

purposes particularly

following stockpiling for more

than 3 months. Topsoil likely

to require chemical and

organic amendment.

Topsoil may be amended or

replaced by compost

generated from site tub

ground mulch or imported

from local suppliers

providing improved

revegetation and erosion

outcomes.




4 PERFORMANCE CRITERIA

The performance criteria for the Soil and Water Management Sub Plan are to:

• Ensure that there are no pollution incidents causing environmental harm;

• Avoid pollution incidents and/or erosion and sedimentation impacts in key sensitive sites

such as Endangered Ecological Communities;

• Maintain background water quality levels in surrounding waterways.

• Control the impact of erosion and sedimentation from earthworks and other construction

activities by implementing effective erosion and sedimentation control measures;

• Prevent pollution by containing all fuel and other chemical spills and by implementing

effective control measure;

• Ensure effective communication is maintained with statutory authorities and all statutory

requirements are carried out to control impacts on the environment and prevent

pollution.




5 POTENTIAL SOURCES OF POLLUTANTS

The potential sources of water pollutants are largely standard for the majority of large scale road construction projects and these are listed in Table 5.1 below. The only non-standard water pollution source considered likely for HEA is the coal mine goaf filling works whereby various mixes of fly-ash grout are pumped into the mining voids to provide structural stability for bridge foundations. The main sources of pollution are fly-ash slurries from the batching and pumping works and mine water if dewatering of the goaf is required. Initial investigations indicate that the mining voids are dry and no dewatering will be required.

Mitigation techniques are provided in Section 6.

Table 5.1: Summary of potential sources of water pollution

Activity Potential Pollution Sources

Geotechnical investigations / drilling

Sediment

Turbidity

Hydrocarbons

Operation of construction compounds and batching plants

Sediment

Turbidity

Concrete slurries

Fly-ash slurries

Clearing

Sediment

Turbidity

Hydrocarbons

Mulching of vegetation Tannins

Hydrocarbons

Soil stripping and stockpiling

Sediment

Turbidity

Hydrocarbons

Construction earthworks Sediment

Turbidity

Hydrocarbons

Bridgeworks and paving

Concrete slurries

Fly-ash slurries

Curing compounds

Hydrocarbons

Acidic mine water

Saline mine water

Operation Hydrocarbons

Heavy metals

Chemicals

Nutrients

Rubber




6 MANAGEMENT AND MITIGATION MEASURES

A range of soil and water management and mitigation measures will be implemented during all phases of the road project with a strong emphasis on the construction phase where land disturbance will be greatest.

As land disturbing activities occur, specific soil and water management measures will be planned and implemented throughout the phases of the project to:

• Divert clean water flows

• Minimise erosion;

• Retain sediment at the source;

• Treat sediment laden run-off; and

• Manage the discharge of run-off from site.

• Rehabilitate disturbed areas as soon as possible

6.1 Progressive erosion and sediment control plans

Erosion and sediment control measures will be designed prior to disturbance, or as site conditions dictate, during a change in site layout, and documented in Progressive Erosion and Sediment Control Plans (PESCP). These may be specific to a site, a sub-site, sub-catchment or individual component of the work. For example:

• Clearing, grubbing and removal of topsoil

• Earthworks

• The installation of a culvert or major drainage structure clearing adjacent to a waterway;

• Bridge sites;

• Compound;

• Environmentally sensitive areas e.g. adjacent to an endangered ecological community;

• Waterway crossings;

• In-stream platforms;

• Creek bank stability works; and

• Work occurring in areas with a high erosion hazard.

PESCPs will include but not be limited to:

• Contours and clean and dirty water drainage paths;

• Limit of disturbance;

• Location and type of control measures;

• Order of works schedule; and

• Specific construction details.

PESCP’s will be developed by construction staff trained and mentored on production of PESCP’s.




Training on the preparation of PESCP’s will be undertaken by the Soil Conservationist.

PESCPs will be presented as a series of drawings (based on construction plans) and will be reviewed and approved by the Environmental Manager (or delegate) and the Alliance Soil Conservationist.

PESCP’s will be prepared prior to any land disturbing activities and will be part of the documentation included on the Ground Disturbance Permit.

6.2 Work Procedures

Work Procedures will be prepared for all activities to ensure sound construction practices are implemented and to minimise the risk of environmental and safety incidents, quality non-conformances or system failures.

The Section Managers, Construction Field Manager and the Environment Manager (or delegates) will develop Work Procedures to ensure suitability and adequacy of meeting specified contract and CEMP requirements. The following work procedure relevant to the prevention of water pollution that are likely to be developed but are not limited to:

• pipe culverts

• drainage structures

• open drains

• kerb and/or gutter

• precast concrete box culverts

• earthworks excavation

• embankment and select

• rock fill embankment

• rock fill gabions and mattresses

• placing concrete in sub base

• placing concrete in base

• excavation and backfill for bridges

• concrete works for bridges

• paving operations, application of curing and bitumen compounds to pavements, saw-

cutting, equipment washout.

• selection of stockpiles

6.3 Environmental Construction Method Statement

In addition to activity specific Work Procedures, Environmental Construction Method Statements (ECMS) shall be prepared for specific activities. These activities shall be determined in conjunction with the EMR. ECMSs shall require the certification of the EMR as being in accordance with the Conditions of Approval and all undertakings made in the EIS and Representations Report.

All ECM’s and Work Procedures will require the development of a PESCP.




Activities that will be covered by ECMS’s are presented in a Matrix in Appendix H of the CEMP Volume 1.

ECMS’s for bridges and works in waterways will be developed in accordance with Alliance Specification G39. Particular issues that will be addressed in the ECMS will include:

• Quick installation of culverts to ensure that transverse drainage is in place during the

early stages of construction;

• Where possible, quick installation of wing walls will be undertaken so that waterway

erosion and sediment impacts are minimised; and

• Working platforms shall be avoided where possible. If a working platform cannot be

avoided then it shall be well designed. Any temporary work platforms constructed within

the creeks for bridge construction purposes will consist of clean rock fill, ensuring that

the potential for erosion is minimised.

6.4 Training

All employees, contractors and utility staff working on site will undergo environmental training in relation to:

• Legal requirements and due diligence;

• Alliance specific erosion and sediment control drivers;

• Erosion;

• Sedimentation;

• Chemical pollution controls;

• Pollution and water quality;

• Emergency response; and

• Spill kits and their use

Key staff will undertake more comprehensive training relevant to their position and/or responsibility including those:

• Responsible for design, installation and maintenance of erosion and sedimentation

controls;

• Involved in the preparation of PESCPs;

• Involved in the treatment and release sediment basins;

• Responsible for the maintenance of chemical and fuel storage areas; and

• Track and trail construction and maintenance.

This training may be provided as ‘toolbox’ training or at a more advanced level by the Environment Manager and/or Alliance Soil Conservationist.

Records will be kept of all personnel undertaking the site induction and training, including the contents of the training, date and name of trainer/s.




6.5 Soil Conservationist

The soil conservationist engaged for the HEA project is John Wright from TREES PTY LTD.

Prior to starting up his own company John was the recognised expert within the D.L.W.C. on soil conservation issues relevant to road construction which is still his area of speciality.

Johns soil conservation advice and services are extensively used by all the main road contractors in NSW.

Johns CV can be found at the following address: http://www.treespl.com/staff_john.htm

In addition Mike Murphy (Certified Professional in Erosion & Sediment Control No. 2389) will be undertaking RTA Peer Review of all soil conservation issues on the HEA project.

This Soil & Water Management Sub Plan was initially prepared by Michael Francombe (Soil Conservationist for Parsons Brinkerhoff and now with KMH Environmental).

Amendments to the Sub Plan as a result of comments received via Agency and Council consultation have been incorporated by John Wright.



HEA-PL-GL-SWP-001-00-03_Soil & Water_Final Page 24

6.6 General Management and Mitigation Measures

Table 6.1 – Management and Mitigation Measures

Management and mitigation measures Responsibility Source of Requirement Timing

General

This Soil and Water Management Sub Plan shall be prepared in

consultation with the DLWC (now DECCW), NSW Fisheries (now

I&I NSW), and relevant Councils. Environmental Manager MCoA87 Prior to construction

This Soil and Water Management Sub Plan shall be certified by the

EMR and approved by the Director General of Planning. Environmental Manager MCoA 21 and MCoA 26 Prior to construction

This Soil and Water Management Sub Plan has been prepared in

accordance with Managing Urban Stormwater and Alliance

Specification G39. Environmental Manager MCoA87 N/A

A Soil Conservationist has been employed on the project to

undertake inspections and provide advice on erosion and sediment

control measures and certify Progressive Erosion and Sediment

Control Plans (PESCP).

The soil conservationist will ensure that the most appropriate

controls are being implemented and that they are being maintained

in an efficient condition at all times and meet the requirements of

any relevant approval/licence condition(s)

Environmental Manager MCoA90 Pre-construction and

construction phases

All stormwater drainage, erosion, sedimentation and water pollution

control systems and facilities will be located, designed, constructed

operated and maintained to meet the requirements of the relevant

authorities including the EPA and the NSW OoW

Design Manager / Senior Project

Engineer/Superintendent MCoA 94

Pre-construction,

construction and post-

construction phases

All water collected during construction which is likely to be

contaminated, shall be tested, treated, handled and disposed of so

that it does not pollute waters.

Senior Project Engineer/Superintendent

MCoA 91 construction phase





Weather forecasts shall be used to guide work activities undertaken

onsite.

Weather forecasts to be checked at the start of each day and prior

to undertaking a new work activity. If rain is imminent, do not

undertake works that may have environmental risk.

Where weather forecasts predict weather conditions which may

pose an environmental risk - site environmental controls will be

checked inspected and secured to reduce erosion and sediment

control impacts as necessary.

Works that may lead to erosion and sedimentation shall not be

scheduled prior to forecasted rainfall events.

Construction Manager / Superintendent

Pre-construction and

construction phases

Bulk hydrocarbons and chemicals will be stored in covered bunded

areas and/or self bunded tanks will be utilised;

Small quantities of hydrocarbons and chemicals will be stored on

bunded pallets;

Refuelling and servicing of plant and equipment will be undertaken

away from sensitive areas;

Hydrocarbon and chemical spill kits will be provided as appropriate

and relevant personnel will be trained in their use;

Maintain spill kits on-site near storage areas and equipment;

Plant and equipped will be maintained in accordance with OEM

requirements to minimise the risk of breakdown and spills; and

All hydrocarbon and chemical spills will be reported, cleaned up and

any contaminated waste will be disposed of lawfully.

Project Manager/ Environment Manager MCoA118 Pre-construction and

construction phases

Sediment basins will be treated with flocculants to facilitate the

settlement of suspended solids as required. The type of flocculent

will be dependent on the soil type, necessary treatment time,

downstream receiving environment and flocculent application

technique.

Flocculent type will also conform to EPL requirement re eco-toxicity

(upon receipt)

Construction Manager & Environment

Manager Construction Phase





Sedimentation basins will be cleaned out on a regular basis as

necessary to ensure the build up of sediment is removed.

No more than 1/3 of the basin capacity in sediment will be allowed

to accumulate before cleaning out is required.

Depth of sediment will be determined either by use of a dip stick or

the installation of a marker post denoting the sediment line

Senior Project Engineer/Superintendent Construction Phase

Rapid stabilisation and rehabilitation of all disturbed areas Senior Project Engineer/Superintendent Construction Phase




6.7 Design


Design

The design team will be briefed on the specific soil and water

management issues for the project and have been included in the risk

assessment process. Environmental Manager

Soils and Construction,

Volume 2d Design phase

Design drawings will show all permanent drainage, erosion and

sediment control measures as well as temporary and permanent water

quality basins.

Highway Lead Design Manager Soils and Construction,

Volume 2d

Design phase

The design will consider the use of bridges and arches instead of

culverts to minimise disturbance to and the diversion of natural

channel and creeks.

Highway Lead Design Manager,

Bridge Lead Design Manager MCoA88 Design phase

The design, construction and operation of construction sediment

basins will comply with the requirements of Managing Urban

Stormwater: Soils and Construction, Volume 1 4th Edition, March

2004, Managing Urban stormwater: Soils and Construction, Volume

2D, Main Road Construction and RTA Specification G38 will be Type

D basins due to the presence of dispersive soils

Design Manager MCoA 92

Blue Book, Volume 2d

RTA Spec G38

Design and construction

phases

Construction sediment basins will be Type D 85th percentile, 5 day

basins except where limited by clearing disturbance limits.

Construction basins will be Type D 80th percentile, 5 day basins when

located away from sensitive areas except where limited by clearing

disturbance limits. The use of smaller basins will be determined with

the DECCW.

Design Manager MCoA 92

Blue Book, Volume 2d

RTA Spec G38


phases

As far as practical, sediment basins will be located in non-vegetated

areas in order to reduce the clearing footprint.

Where possible, sediment basin design shall maximise the distance

between basin outlets and adjacent environmentally sensitive areas.

Design Manager Design and construction

phases

The construction sediment basins and associated equipment will

include: Design Manager RTA App 14 of SWTC Design and construction

phases





• flow control structures (i.e. baffles, bypass weir), at the inlet of

the construction sediment basin, that form an inlet chamber

and limit flows to a maximum velocity to 0.5m/s. The size

and location of the inlet chamber will allow desilting by

conventional earthmoving equipment such as a backhoe;

• internal baffles where the length-to-width ratio of the

construction sediment basin is less than 3:1;

• automatic basin flocculent dosing stations that comply with

the requirements of E.4.2 of Managing Urban Stormwater:

Soils and Construction Volume 1 4th Edition, March 2004 and

use liquid flocculants that comply with the requirements of

Specification G38.

• forebays to trap coarse sediments; and

• floating siphon devices that decant the construction sediment

basin by siphoning water from the top of the water column.

• An emergency outlet or spillway

• Outlet protection to reduce erosion downstream

• Compacted earth embankments or a rock filled wire basked

wall with geofabric lining;

A spill containment system to capture accidental chemical and fuel

spills during operation of the Works will be designed to minimise the

impacts of accidental spills, including those on environmentally

sensitive areas.

Those areas requiring treatment during the operation of the Works will

be identified by a Water Quality and Spills Risk Assessment.

Agreement to the Water Quality and Spills Risk Assessment will be

made with the relevant Authorities.

Design Manager

MCoA 95

RTA App 14, s.14.2.3(b)

RTA Code of Practice for

Water Management (1999)

Design phase

The Alliance will design and construct an operational water quality

system that may include swales, wet/dry basins, bioretention base

ponds and constructed wetlands to control the intensity of and remove

pollutants from stormwater runoff (including from pavements and

Design Manager / Construction

Manager

RTA App 14, s.14.2.2

Design and Construction

phase





bridges) prior to discharge.

The Alliance will design and construct operational water quality

systems in those areas identified by a Water Quality and Spills Risk

Assessment.




Manager

RTA App 14, s.14.2.2


phase

The Alliance will design and construct a spill containment system to

capture accidental chemical and fuel spills during operation of the

Works and minimise the impacts of accidental spills, including those

on environmentally sensitive areas.

Those areas requiring treatment during the operation of the Works will

be identified by a Water Quality and Spills Risk Assessment.




Manager

RTA App 14, s.14.2.3


phase

Operational spill basins shall have a minimum capacity of 20000L. Highway Lead Design Manager

MCoA 95

App 14, s.14.2.3(b)

RTA Code of Practice for

Water Management (1999)

Operational phase

The design will maximise the segregation of clean and dirty water

catchments during both the construction and operational phases of the

project.


Volume 2d


phases

The design of culverts will allow for the temporary stable bypass of

clean cross drainage during construction. Highway Lead Design Manager


Volume 2d


phases

Lined catch drains and berm drains will be provided to protect cut

batters and to divert clean run on water through or away from

disturbed areas.


Volume 2d


phases

Kerbs, gutters or dykes discharging into lined batter drains will be

provided to protect fill batters. Highway Lead Design Manager


Volume 2d


phases





Culvert and drainage structures will be designed and constructed to

minimise impacts on creeks and fish passage, e.g. invert of culverts

and pipes will be 200mm below the bed level of creeks;

Highway Lead Design Manager App 5, Table 4 Design, construction and

operational phases

Bridge piers, scour protection and abutments shall be located to

minimise disturbance to the bed and banks of creeks and flow lines. Bridge Lead Design Manager App 5, Table 4 Construction Phase




6.8 Access and Site Set Up


Access and Site Set Up

Develop plan showing which access tracks are to be used and which

tracks are NO Go areas Construction Manager Construction Phase

Erosion and sedimentation controls will be installed prior to any land

disturbance to ensure that all runoff from the site is managed

appropriately. Construction Manager

Soils and Construction

Volume 2d Construction Phase

Where natural surface levels allow, sediment basins will be

constructed prior to the commencement of top soil stripping and will be

operational when subsoil earthworks commence.

Construction Manager Construction Phase

Sedimentation basins will collect sediment-laden run-off from

disturbed areas of the construction site. Sediment basins will be

located to maximise the collection of turbid runoff.

Construction

Manager/Environment Manager Construction Phase

Construction water sources will include:

• project sedimentation basins;

• local non-potable supplies (e.g. farm dams, local creeks, bore

water);

• local potable supplies;

• constructed dams

A permit to extract water from local creeks will be sought from DECCW

(Office of Water) in accordance with the Water Management Act 2000

if applicable.

Environment Manager Construction Phase




6.9 Clearing

Clearing - Management and mitigation measures Responsibility Source of Requirement Timing

Clearing

Wherever possible during clearing, soil surface cover will be

maintained, including use of the cut stump method to minimise soil

exposure to erosion for clearing near waterways. Construction Manager App 15 s.15.5.1 Construction phase

Develop work procedures and PESCP. Construction Manager Construction phase

PESCP’s to be approved by the Environmental Manager and Soil

Conservationist prior to commencing new works. Construction Manager

Construction phase

Where possible divert all clean water flows away or around the site

prior to clearing commences Construction Manager Construction phase

Where possible install sediment basins prior to clearing Construction Manager

Site vegetation will be either removed from site for re-use/sale, or tub

ground and either stockpiled (& managed to become compost for

revegetation purposes) or windrowed to form sediment retention

berms.

Construction Manager MCoA64 Construction phase

Clearing will not involve the removal of groundcover/grasses and

topsoil in order to retain the runoff infiltration capacity of the

groundcover for as long as possible, and to minimise topsoil runoff. Senior Project Engineer Construction phase

The topsoil will be kept in place in areas not being excavated to

prevent exposure of the subsoil during clearing operations. Senior Project Engineer Construction phase

Where applicable, temporary windrows will be used to keep runoff

from spilling over embankment batters during construction, and used

in combination with temporary batter drains to enable controlled

discharge of runoff down battered slopes without causing erosion.

Senior Project Engineer Construction phase




6.10 Earthworks


Earthworks

Develop Work Method Statements and PESCP’s for all earthworks Senior Project

Engineer/Superintendent Construction phase



Spoil, select material, sub soils, mulch or compost stockpiles will:

• Generally be located within the road reserve, and in areas

identified for future disturbance or at sites identified for

compound and or batching plant location;

• Be located at least 20 metres from any creeks, water bodies

or a flood prone area;

• Be constructed as low, flat elongated mounds where

construction room permits;

• Have sediment fences down slope and earth banks upslope

to divert run-on water

• Stockpiles are not to be located on native vegetation;

• Soil stockpiles to be protected from wind erosion by covering

with geotextile until required.

All site personnel Construction phase

Any stored topsoil stockpiles will be protected from water and wind

erosion by seeding with a sterile cover crop or by covering with geo-

textile fabric until required.

Senior Project

Engineer/Superintendent

App 15, s. 15.6.3(k) Construction phase

No plant or operations will be located within buffer zones (within 20m)

along waterways (to reduce risk of ground disturbance / potential fuel

spillage) unless those waterways are located outside works areas,

and/or all waterways are temporarily diverted during works and/or

other appropriate mitigation measures are employed, where

practicable.

Where not practical, other controls (to be determined on a case by

case basis and detailed in the relevant PESCP) would be employed

Senior Project






between the waterway and works area.

Erosion and sediment control devices to be implemented on site

during construction is likely to include:

• Soft and hard armour lined drains;

• Diversion banks and drains;

• Trafficable inclined diversion banks;

• Soil stabilisers;

• Culvert inlet and outlet protection;

• Amelioration of dispersive, acidic and low nutrient soils;

• Progressive revegetation;

• Hydro-mulching;

• Compost blankets;

• Sediment traps;

• Sediment basins;

• Mulch/compost bunds; and

• Coagulants and/or flocculants.

Project Manager/Environment

Manager/Superintendent

Construction phase

Where areas are identified as being most vulnerable to runoff from the

highway or disturbed areas or where the terrain suits installation of

basins, surface runoff from the road will undergo sufficient treatment

using a system of water quality control ponds incorporating traps to

contain spills of hazardous materials and ensure that runoff meets

relevant guidelines for discharge into wetlands or watercourses.

Construction Manager/Project

Manager App 15, s. 15.4 Construction phase

Diversion banks will be constructed at an appropriate grade to

minimise soil erosion (less than 1%). Project Manager/Environment


IECA(2008) Construction phase

Energy dissipaters will be installed at the end of diversion banks of any

overland flowpaths leading from the disturbed area, to slow flow

velocities to non-erodible levels.



Soils and Construction

Volume 2d

Prior to and during

construction





Designation and marking of transport routes across undisturbed

portions of the site will be undertaken to ensure minimal unnecessary

vegetation disturbance.



Prior to and during

construction

Undertake progressive revegetation of disturbed areas. Project Manager/Environment


Prior to and during

construction

Delineate clearing limits to confine construction activities within the

necessary construction area(s). Project Manager/Environment


Prior to and during

construction

Control measures will be maintained until the site is stable and 70%

soil surface cover has been achieved. Once the project site has been

stabilised, temporary sediment controls will be removed.


Manager/Superintendent MCoA94

Prior to and during

construction

Any permanent water-retaining structures or other erosion and water

management controls will be routinely maintained. Project Manager/Environment


App 15 Prior to and during

construction

Ensure wheels, tracks and body surfaces of plant and vehicles leaving

the site are free of mud or sediment to minimise the potential for mud

tracking on public roads. Superintendent MCoA115

Prior to and during

construction

Road sweepers will be utilised if conventional measures such as

rumble grids to not prevent mud tracking on public roads. Project Manager/Senior Project

Engineer

MCoA115 Prior to and during

construction




6.11 Drainage and Bridgeworks


Drainage and Bridgeworks

Develop Work Method Statements and PESCP’s for drainage and

bridge works. Senior Project




Temporary waterway crossings will be constructed over local

waterways to facilitate access for earthworks activities and the

construction of bridges only if absolutely necessary. The following

mitigation measures and controls would apply to work within

waterways:

• Disturbance of watercourses by construction works will be

avoided wherever possible ;

• Work Procedures will be prepared for work in any natural

waterway;

• Appropriately sized rock will be used for constructing

waterway crossings;

• Personnel and sub-contractors will be made aware of their

environmental responsibilities through induction and

environmental training;

• There will be no temporary stockpiles of materials nor

machinery stored in drainage lines;

Where work in waterways is required (e.g. culvert installation), these

works will be carried out in the shortest possible timeframe and in dry

conditions; Adequate erosion protection controls shall be installed prior

to forecasted rainfall events.

Aquatic habitat in the form of snags, gravel bars, in-stream vegetation

(rushes, sedges), tree roots, logs and similar will be maintained in-situ

where possible or replaced following construction;

Senior Project

Engineer/Superintendent

MCoA68, App 4 s. 4.15.1,

App 5 Table 4

Construction phase





Adequate systems will be developed for liaison with regulatory

authorities and local councils regarding installation of all waterway

structures (e.g. Environmental Review Group Meetings); and

Construction phase

Platforms and temporary crossings will consist of rock containing nil to

minimal fines that are not capped. Some fines may be used at the

surface level for stability requirements , however these shall be capped

to reduce the erosion potential.

Waterway rehabilitation will be instigated immediately following

construction utilising appropriate stabilisation products and species

endemic to the area. Restoration may also involve the provision of in-

stream habitat features such as riffles, pools and snags.

Appropriate erosion and sedimentation control measures, such as

sediment fences, sediment curtains and/or other controls will be

constructed along creeks and where the slope of existing ground

requires to ensure that waterways are separated from active

work/exposed areas.


Manager

Construction phase

Erosion protection will be provided at the inlet/outlets of culverts and

under bridges where appropriate to minimise erosion. RTA, NPWS, II

NSW (Fisheries) and the Blue Book recommendations will be adopted

in the detailed design phase to ensure that erosion protection is

adequate. Erosion protection will be designed in an environmentally

sensitive manner, taking into account aquatic ecology and fish

movement as well as stream issues. Bank and bed protection will be

considered.


Manager MCoA68, App5 Table 4

Construction phase

Depending on the type of works, construction of an impervious bund

(e.g. cofferdam) will be considered to prevent water entering the area

of works.

Should cofferdams be required the process to install/ dewater and

remove coffer dams will be developed prior to the installation of any

coffer dams and best management practice will be implemented in

developing WMS & PESCP’s for their instillation and operation.

Where construction of temporary work platforms is necessary within



Construction phase





creeks for bridge construction purposes, the platform will be designed

to minimise the disturbance to the creek bed.

Should dewatering of coffer dams be required appropriate

methodology such as pumping out to a nearby basin or via watercart

shall be investigated. Release of coffer dam water directly to

waterways shall not be permitted.



Prior to commencement of

construction

Barriers will be constructed on crossings or around working areas of

watercourses during bridge cleaning and repainting and other works to

prevent dust and spray entering the watercourse.


Manager

Construction and operational

phases

The placement of concrete into forms in or close to any watercourse

will be carefully controlled. The use of quick setting mixes may be

appropriate in some cases to minimise the risk of water pollution.

Project Manager/Senior Project

Engineer Construction phase

Concrete pours will not be undertaken during rainfall where there is a

risk of water pollution occurring. Project Manager/Senior Project

Engineer

Construction phase

Steel or concrete piles for bridges will be used where possible to

minimise the potential for groundwater contamination, particularly in

alluvial aquifers.

Project Manager/Senior Project

Engineer Construction phase

Specific work procedures will be prepared for grout filling of the

underground mining voids. The work procedures will include measures

for the management of potentially saline and/or acidic mine water,

minimise the potential for contamination of coal seam groundwater

aquifers and for monitoring of impacts on coal seam groundwater

aquifers.


Manager

MCoA96 Prior to construction

Groundwater will not be discharged to any watercourse or drain

without treatment to ensure it meets necessary water quality discharge

criteria.


Manager MCoA91 Construction phase

Diversion banks/drains will be installed upstream of construction

activities where practicable to ensure run-on water is diverted around

disturbed areas.




Volume 2d

Prior to and during

construction





Catch drains at the downstream boundary of construction activities will

also be created (wherever possible) to ensure any sediment laden

runoff is contained and directed toward treatment areas and not

permitted to flow onto downstream undisturbed areas and will be lined

where the flow velocity exceeds the erosive resistance of the soil.

Where the installation of catch drains is not possible temporary cross-

drains will be scribed in at regular intervals with temporary checks

placed in the drains to lower the velocity within the drains to prevent

erosion.




Volume 2d

Prior to and during

construction




6.12 Paving and Vehicle Movement


Paving and Vehicle Movement

The following water quality controls will be provided for the batch

plants as required:

• Perimeter bunds to divert run-on away from the site;

• Installation of a first flush water pollution management

system;

• Immediate clean up of any spillage of chemicals, fuels or oils .

Water discharge requirements from the batch plant will be as detailed

in the EPL.


Manager Construction phase

Truck wash downs and cement truck washouts conducted in approved

areas only Superintendent

Construction phase

Water recycling will be encouraged (refer to s5.7 of the Waste

Management & Re-Use Sub Plan for further details) Project Manager/Environment

Manager

All excess concrete and waste materials stored in bunded areas prior

to reuse or disposal.

Details of concrete curing compounds and treatments will be outlined

in the work procedure to be prepared for concreting paving operations.

This will contain a description of the procedure used including

equipment, chemicals and primary/secondary controls to capture

curing compound run-off.

Vehicles will use defined access routes and tracks at all times (to be

detailed in the Traffic Management Plan).

All spoil will be covered during transportation on public roads.


Manager

Senior Project Engineer

Superintendent

MCoA115 Prior to construction

All phases

Construction phase

Road sweepers will be utilised as necessary to minimise sediment

being washed into nearby drains and watercourses. Superintendent MCoA115 Construction phase





Concrete mixers and pump trucks will be washed out at designated

wash-out locations on-site. Superintendent Construction phase

Specific concrete washout locations to be installed at batching plant for

major concrete wash outs and along the alignment for minor concrete

washouts Superintendent Construction phase

Training will be provided to personnel authorised to manage and

release the basins;

Waste water captured in storage bunds will be visually assessed for

contamination prior to being released. Hydrocarbon contamination will

be removed using appropriate absorbent materials;

Washdown areas for equipment will be located in bunded areas away

from watercourses and wetlands;

Concrete washout areas and pits will be adequately sized, located

away from drainage lines and maintained regularly; and

Waste water produced by the batch plants will be captured and reused

where possible.


Manager

Construction phase

Slurry from saw cutting and curing compounds will be retained close to

the source as far as possible. Project Manager/Senior Project

Engineer

Construction phase




6.13 Rehabilitation and Landscaping


Rehabilitation and Landscaping

Soil erosion will be minimised by establishing vegetation quickly on

disturbed areas. Permanent vegetation will be established on all

disturbed areas subject to erosion and where no further regarding or

activity is proposed. Works will be undertaken in accordance with

Alliance Specifications R178 and R179.


Manager MCoA 89

Construction phase

The following measures will be adopted to stabilise and restore

disturbed areas of the construction site:

• Revegetation works will be undertaken progressively and in

conjunction with earthworks to minimise the time that an area

is exposed;

• Topsoil will be reused in areas as close as possible to its

source location to maximise the benefits available from the

existing seed bank;

• Batters will be stabilised and revegetated as quickly as

possible to minimise erosion and sedimentation in

accordance with Alliance Specifications R178 and R179;

• Site soils will be tested for agronomic and erosion parameters

and soils will be ameliorated accordingly; and

• Revegetation will be undertaken using direct seeding, hydro-

mulching, compost blankets or direct planting.


Manager / Landscape Manager

MCoA 89

App 15, s. 15.6.3

Construction phase

Construction sediment basins that are retained during the operation

phase will be removed once the vegetation cover in the catchment

area has achieved 70% and water quality has stabilised. Following

removal the disturbed areas will be revegetated.

For permanent water quality basins the modification process following

completion of construction will involve allowing the natural seeding of

aquatic plant species (macrophytes) to assist with sediment settlement

and nutrient removal processes.

Senior Project

Engineer/Superintendent/Environ

ment Manager

MCoA94 Operational phase





All exposed areas to be stabilised (that is, compacted, sealed or

vegetated) as soon as practicable following completion of works. Senior Project Engineer Construction and operational

phase

At the completion of the work, all disturbed areas to be restored as

closely as practicable to their condition prior to completion of works. Senior Project Engineer Construction and operational

phase




7 INSPECTIONS

Inspections will take place on a regular basis to ensure appropriate mitigation measures and controls are being provided and that they are effective. Site monitoring by an appropriately qualified environmental scientist or person with similar expertise in soil and water management will include the following:

Table 7.1: Inspection Requirements

Inspection Requirements When Who

Construction

Informal visual checks of all erosion and sedimentation devices by the Senior Project Engineer and Superintendent (or

delegate) to ensure that controls have been provided where required and/or are functioning correctly. Any deficient controls

will be noted and action will be taken to address.

Inspections by the Environment Staff and/or erosion and sediment control crew.

Rainfall depths/levels.

Daily and after a

rainfall event

Senior Project

Engineer and

Superintendent (or

delegate)

Environment Staff

and Maintenance

Crews

Inspections by the Environment Staff and completion of environmental checklists:

• Check that controls are being maintained in an efficient condition;

• Check that controls meet the requirements of any relevant approval and/or licence conditions; and inspections to

inform the update of PESCPs and to identify where new controls are required.

Weekly and after a

rainfall event

Environment Staff

(and site engineers

periodically as per

site commitment

matrix requirements).

Joint inspections with the Alliance Soil Conservationist , RTA client representatives and Project EMR during clearing and

earthworks phases.

Fortnightly

Superintendent/ Soil

Conservationists,

Project EMR,

Alliance

Environmental Staff

and RTA




Inspection Requirements When Who

Joint inspections with regulatory agencies representatives, project EMR, relevant site staff, RTA client representatives and

Soil Conservationist.

Monthly

Superintendent/ Soil

Conservationists,

Project EMR,

Environmental Staff,

Agency

representatives and

RTA.

Reporting to DECCW on compliance with EPL conditions. Annually

Alliance Environment

Staff

Inspections following significant rainfall (10mm of rainfall within a 24 hour period) by the Project Engineer, Superintendent

and Environmental Officer.

Event based

Project Engineer,

Superintendent and

Alliance

environmental staff.

Inspection to assess whether there have been any discharges to receiving waters for rainfall events up to and including the

design rainfall event for control structures (i.e. basins).

Event based

Project Engineer,

Superintendent and

Alliance

environmental staff.

Post-construction

Ensure sediment and erosion controls are removed on completion of the rehabilitation works. On completion Environment

Manager/

Superintendent




8 MONITORING AND REPORTING

Table 8.1: Monitoring and Reporting Requirements

Pre-construction

Monthly water quality monitoring will be undertaken where disturbance to the creek bed or near the creek line would occur

during construction activities.

Monthly Environment

Manager

Monitoring will be carried out to measure the following parameters and indicators: pH; Electrical conductivity; Turbidity;

Aluminium (if aluminium based flocculants are proposed to be used) and Dissolved Oxygen. Monthly

Environment

Manager

Construction

Water quality monitoring will be undertaken upstream and downstream of the construction areas monthly and following

significant rainfall events greater than or equal to 10mm.

Monitoring will be carried out to measure the following parameters and indicators: pH; Electrical conductivity; Turbidity;

Aluminium (if aluminium based flocculants are used during construction), Dissolved Oxygen and Temperature

Monitoring will be undertaken twice monthly (1 sample during dry weather and 1 sample per month during rainfall events).

Generally where there is a 10% exceedance of downstream samples compared to upstream samples an investigation will be

undertaken to determine whether the elevated downstream results are as a result of construction impacts. Results will also be

compared with the ANZECC Water Guidelines 2000 or update.

An appropriately qualified person will undertake regular inspections and maintenance downstream of construction areas at

locations where water quality samples are taken. Refer to Appendix A for an example Water Quality Monitoring Work

Procedure.

Basins will be monitored for turbidity, pH and oil and grease before being discharged. pH adjustment and flocculation will be

undertaken as required.

Monthly Environment

Manager

Post -Construction

Sampling Sites - Post-construction monitoring sites should be representative of the impact site runoff will have on receiving

waters. The number of sampling sites would likely be less than in the construction phase, dependent on changes in site

hydrological conditions following the installation of the operational stormwater system.

Sampling frequency - Recommended default sampling frequency for post-construction monitoring is once per month. If a

Monthly Environment

manager




number of results demonstrate that the site or parts of the site have stabilised, the sampling frequency and sampling locations

may be reviewed and reduced or discontinued.

Parameters - Post-construction monitoring parameters will be the same as those used during the construction of the project.

Individual parameters may be withdrawn from the program as the site stabilises or the parameter is demonstrated to be no

longer of concern. For example, where erosion has been controlled through re-vegetation and all operational stormwater

controls have been installed.

Interpretation of results - If the results exceed the site criteria for any sample respond in the same way as during the

Construction phase and report to relevant Government agencies as necessary.

If individual parameters or sampling sites are to be withdrawn from the program, it should be demonstrated that there is no

longer an impact over a minimum period of 2 months.




9 CORRECTIVE ACTION

Possible non-conformances may include non-compliance with the management measures and mitigation strategies outlined in Section 6. All incidents and non-conformances are to be reported and investigated and corrected in accordance with Section 4 of the CFEMP

Specific corrective action items for the soil and water management Sub Plan are outlined below:

• Sediment controls not effectively maintained and reinstatement or remedial action

required; and

• Spill or release of sediment laden water occurs, an incident report is submitted and

remedial action required.

This management plan will be reviewed during the construction period based on results from monitoring, observations, non-conformance or complaints. The review will allow adjustments to occur to the plan if they are found to be beneficial, or if measures need adjusting. All project staff will be notified of changes made to this Sub Plan.




APPENDIX A – WATER QUALITY MONITORING WORK PROCEDURE


00 22-3-10 Erran Woodward Tracey Doczy Howard

Chemney




SCOPE

This document describes the procedures for the monitoring of water quality in streams and rivers which intersect the footprint of the Hunter Expressway Alliance Project (the Project).

The objective of the water monitoring is to identify any disturbance to waterways caused by clearing and construction of the Project. By assessing water quality both before and after (temporal replication) and upstream and downstream (spatial replication) of the construction works, changes in water quality will be recognised, causes identified and actions can be taken to immediately rectify and prevent any further environmental damage.

Guidelines for the water quality monitoring and reporting are outlined in the HEA Soil and Water management Sub Plan. These guidelines will be used as the foundations for this Monitoring Procedure. All monitoring will be undertaken in accordance to the Monitoring Job Safety and Environment Analysis (JSEA).

ASSESSMENT

Water quality parameters to be assessed include:

• pH

• Electrical Conductivity

• Turbidity

• Dissolved oxygen

• Temperature

• Salinity

• Aluminium (if aluminium flocculates are used during sediment basin treatment)

Site observations including weather, colour, frothing, odour, flow, surfactants, construction activities and aquatic organisms will be recorded during sampling.

Data will be obtained and stored using the Yeo-Kal Multi purpose water quality analyser (Model 611 or Model 615). This equipment will be regularly serviced and calibrated to manufacturer’s directions to ensure reliable results.

In the case where water samples need to be analysed for heavy metals, oils and organic pollutants, samples will be collected and sent in accordance to laboratory specifications to a NATA accredited laboratory for analysis.

SITE LOCATIONS

Water quality monitoring will occur in waterways both upstream and downstream of the construction and areas of disturbance from construction may occur. These waterways include:




Table 1

Waterway Site Name Location

Minmi Creek MC 0.510km

Blue Gum Creek BGC 2.590km

Surveyors Creek 1st Occurrence SC1OC 4.400km

Surveyors Creek 2nd Occurrence SC2OC 5.600km

Surveyors Creek 3rd Occurrence SC3OC 10.400km

Wallis Creek WC1 10.490km

Maps showing indicative sampling locations are included within the HEA Construction Environmental Management Plan.

MONITORING PROCEDURE

1. Preparing the equipment:

The operator must familiarise themselves with the Yeo-Kal user manual before attempting to undertake water quality monitoring. Monitoring shall only be undertaken by Environmental Officers with relevant training and experience. Ensure the Yeo-Kal equipment is prepared for use by removing the protective seal from the pH sensor and plugging in the probe cord to the connection labelled “Sensor”. The equipment should be regularly calibrated in the field (using standard solutions) and at least annually by the manufacturer (Yeokal) to ensure accuracy.

Calibration logs / certificates to be maintained for auditing purposes.

2. Collecting data:

After reaching the site, remove probe from container and place into the water without disturbing sediment. Readings should settle within a few seconds, but if readings remain inconsistent wait a short period of time until readings stabilise. While waiting, record site data and observations as mentioned above. Store results by pressing STORE on unit and record the number which will flash up. Return probe to case and move to next site.

3. Retrieving the data:

Data from the Yeo-Kal unit can be retrieved by plugging in the cable from the computer port to the COMM connector on the unit. Open the Yeo-Kal software and in the file drop window click ‘Read data from instrument’. Turn the instrument on and in the menu find ‘download data’ and press enter. Once data has downloaded find ‘clear stored data’ and press enter. This will clear all the stored data from the memory.




MONITORING FREQUENCY

Pre Construction:

As defined in the SWMSP, initial pre construction water quality monitoring was undertaken in 2007 and has been continuing on a regular basis since February 2009.

During Construction:

Monitoring will occur twice monthly during Dry and Wet Weather. For the purpose of this monitoring procedure, Wet Weather has been defined as precipitation exceeding 10 millimetres within 24hours. This value has been determined to allow enough precipitation to results in runoff.

Rainfall measurements will be determined by the Weather Station at each Zone’s compound (office locations yet to be determined). Each Zone will determine a wet weather event independently.

There will be three construction zones as follows:

• Zone 1: F3 (ch 0000) – Stockrington Road (ch 1400)

• Zone 2: Stockrington Road (ch 1400) – Rest Area (ch 8100)

• Zone 3: Rest Area (ch 8100) – project end (12900)

Post Construction:

Water quality monitoring will continue in the vein of preconstruction monitoring as determined within the Operational Environmental Management Plan (yet to be finalised).

Trigger Values

Trigger values during construction will be a 20% exceedance of downstream samples compared to upstream samples.

ANZECC Guidelines may not be used for trigger values but may be consulted as a reference in any investigations prompted by discrepancies greater than 20%. Due to the variability of individual creeks and catchments within the construction area, it is believed that the best reference data will be that of the pre construction water quality monitoring.

Actions Triggered

Once identified, an investigation will be undertaken by the Environmental Manager and Environmental Officer to determine the cause of the discrepancy. If the cause is due to Project impacts, the Zone Coordinator will discuss remediation and/or preventative actions with the relevant site manager. If required an Environmental Incident or Non Conformance Report may be initiated.




Reporting

Results of all monitoring, including a description of all exceedances and consequent investigations and alterations to works, will be reported monthly to the Alliance Leadership Team, DECC and the RTA.




APPENDIX B – DEWATERING PROCEDURE


00 22-5-10 Erran Woodward Tracey Doczy Howard

Chemney



HEA - DEWATERING PROCEDURE

Under the Protection of the Environment Operations Act (1997), there is a legal responsibility to ensure that runoff leaving site has an acceptable water quality standard. This procedure must be tool-boxed to all site personnel involved in dewatering activities. Controlled dewatering may occur from sedimentation basins, farm dams and construction excavations. Dirty water must not be allowed to enter any waterway. Consult environment team for further information.

Controlled dewatering may occur from sedimentation basins, farm dams and construction excavations. Any movement of water must be accompanied by a Water Movement Permit (attached) which has been correctly completed by either the operator of water cart or supervisor of the de-watering, and a member of the Environment staff. A Water Movement Permit is required for all movement of water including:

• Dewatering from a farm dam, sediment basin, cuts, trenches or excavated areas, or

• taking water from any extraction point for any purpose.

GENERAL NOTES:

Where possible water should be used for dust suppression activities.

• Water shall not be discharged directly into a drain, creek, river or lake unless it has been

tested and meets our Environmental Protection Licence (EPL) water quality standards.

Consult Environment Team for EPL details.

• Floats and/or other devices must be used on the pump inlet, to ensure that the inlet does

not come into contact with sediment settled at the bottom of the basin or pond.

• When pumping to a grassed area the ground at the pump outlet must be stable and not

erosive. Rock wrapped in geofabric may be used to stabilise the outlet point.

• Visual checks of suspended solids level should be undertaken regularly to determine the

effectiveness of the controls.

• De-watering activities where pumps are in use must be attended by an appropriate site

representative at all times.

PROCEDURES:

Unless otherwise specified by Environment Manager, the only licensed discharge points are sediment basins. Water quality parameters and their exceedance levels are identified in the license (yet to be supplied).

1. In cuts/ large excavated areas:

Methods of dewatering areas in cuts or other large excavated areas include the following: Cut a drain to direct unwanted stored water to an adjacent sediment basin only when it has the capacity to take the volume of stored water with no overflow from the basin. The basin will then be flocculated as necessary and released once tested and the desired water quality standard has



been achieved.

If adjacent sediment basins are full or don’t have the capacity to take the majority of the stored water, the stored water will either be flocculated in situ, tested and released to an appropriate area (eg. grassed area, lined catch drain) once the desired water quality standards has been achieved or, pumped into a water cart and taken to another sediment basin/s which does have the required capacity. The water cart will pump the water into the sediment basin, the basin flocculated, tested and discharged once an acceptable water quality standard has been achieved. Another alternative is to use the water in the water cart for dust suppression purposes on another section of the project where needed. When dewatering, it is important to use a floating inlet to prevent sediment from being extracted from the basin.

2. Trenches, etc. (smaller excavations)

Methods of dewatering in these situations include the following: Water in trenches, etc will be pumped to an adjacent sediment basin if it has adequate capacity with no overflow from the basin. A tail-out drain may be cut directing water from a trench, depending upon its depth and the volume of water, into an adjacent sediment fence or sediment trap.

3. Dewatering of contaminated areas

Where unwanted water is stored in areas that are known to be contaminated or where there is potential for contamination, the water will be tested to determine the contaminant and level of contamination, which will dictate the best method of treatment and disposal. Consult Environment Staff for further information.

4. Sediment basins

All sediment basins to be inspected for capacity and water quality immediately following cessation of a rain period. If water is to be used for construction purposes (e.g. compaction, dust control) no treatment is required. However, the water should be removed to re-secure design capacity within 5 days. Before all de-watering the parameters of pH, T.S.S. and oil and grease are to be tested. Treatment should commence approximately 2 to 4 days before dewatering deadline to allow enough time for settlement of flocculants. Treatment should be undertaken as follows:

pH

• Test basin water with meter

• No action if pH reading between 6.5 and 8.5

• Lime to be added if pH below 6.5

• Hydrochloric Acid (32% Muriatic) or Sulfuric Acid to be added if pH above 8.5

• Determine volume of water in basin.

• Determine percentage of lime or acid required by taking a 10 litre sample of basin water

and adding a known amount of lime or acid (initially 0.004%). If the pH is still not

acceptable, vary the amount of lime or acid until within the limits.

• Once the required percentage has been determined, calculate the actual amount of lime or

acid to be added by multiplying the volume of water in the basin by the determined

percentage.

• Add the required amount of lime or acid to the basin



• Mix the water in the sediment basin well

• Treat for pH prior to T.S.S.

T.S.S

• Test basin water by comparing with water samples contained in jars with representative

readings up to 100mg/l created through laboratory testing. This will enable a relatively

accurate comparison which will be verified by laboratory testing approximately every six (6)

rainfall events.

• No action if T.S.S. reading <50mg/l.

• If basins require flocculation (e.g. T.S.S. >50mg/l), gypsum is to be immediately applied

evenly across the top of the water at the manufacturers recommended dosage initially,

then at an acceptable rate (i.e. trial and error as different for each basin) should more

flocculants be required.

• Basins should be monitored daily after flocculation until desired TSS is achieved and to

assist in determination of optimal dosage levels.

• Methods of application to include:

- broadcast by shovels on small basins (i.e. <200m3); general recommended dosage

is 30kg/100 cubic meters. Spreading powder evenly and thinly (i.e. “dusting”) is

recommended.

- mixing in a drum with water and pumping through a hose on large basins (i.e.

>200m3).

- spraying from a water tanker.

- Use liquid gypsum, recommended dosage of 40L/megalitre

• When spraying flocculants the mixture must hit the water at between 10 to 20 degrees to

increase surface areas exposure to the water column.

• When using liquid gypsum “Hydro-Gyp” the solution must be mixed before use to ensure

gypsum is evenly suspended throughout mixture. This is best achieved using an aeration

device at 3 bars of pressure for approximately 15 minutes.

Oil and Grease

• Examine surface of water for evidence (e.g. sheen, discoloration).

• No action if no visual contamination.

• Oil absorbent material to be spread if there is contamination (e.g. cell-u-sorb). Leave

basins to compensate for 24 to 48 hours.

• After retesting, and once the above field tests indicate, the water quality is acceptable, the

stop valve should be opened by two or three notches, for discharge (ie approximately 10%

to enable emptying within a 24 – 36 hour period to prevent sediment being stirred up by

fast release of water and erosion at the outlet).

• The process above and the retesting may need to be repeated if acceptable water quality

is not achieved initially.

• Once water in the basins has been released the stop valve must be closed for the next

rainfall event.

• Records to be kept of the rainfall events, inspections undertaken, field tests undertaken,

dosage rates and when basin water is released etc. (Refer to the attached checklist).



• The whole process of water quality management in sediment basins must be completed

within 5 days of cessation of a rain period. Notify Environment Manager if this timeframe is

not achieved.

5. Farm Dams

On occasion existing farm dams within the proposed alignment will require dewatering prior to excavation. The following precautions must be undertaken:

• Check with Environment Team prior to dewatering to ensure additional approvals/permits

are not required.

• Environment Team shall check if noxious weeds are observed. Manage noxious weeds

prior to dewatering in consultation with Environment Staff.

• Environment staff shall also check for Mosquitofish. Where Mosquitofish are observed all

water extraction intake pipes shall be fitted inside a mesh or gauze cage (1 mm

mesh/gauze diameter) to prevent the dispersal of the Mosquito Fish into other areas.

Floats and/or other devices must be used on the pump inlet, to ensure that the inlet does not come into contact with sediment settled at the bottom of the basin or pond. When pumping to a grassed area the ground at the pump outlet must be stable and not erosive. Rock wrapped in geofabric may be used to stabilise the outlet point and filter water being pumped. Visual checks of suspended solids level should be undertaken regularly to determine the effectiveness of the controls. De-watering activities are to be attended by a site representative at all times.

Picture of a Mosquitofish – generally 4cm to 7cm in size

6. Management of Sub-Contractors During the site induction, all subcontractors will be made aware of their obligations regarding relevant consent conditions, legislative requirements and any licence requirements. This will include activities such as dewatering that could lead to a breach of any of the consent conditions, license conditions and legislative requirements. Subcontractors will be made aware that there is a work method statement to ensure the appropriate protocol for dewatering is followed. In situations where sub-contractors will require areas of work to be dewatered, they must inform the appropriate Alliance supervisor (foreman, superintendent) of their work that an area of their work requires dewatering. The supervisor will then implement the appropriate dewatering method for the circumstance. Records will be kept by both the Thiess supervisor and the sub-contractor of the area being dewatered, the date, method of dewatering, discharge point, who undertook the work and any test results.



Under no circumstance should the sub-contractor undertake dewatering activities without informing the relevant Alliance supervisor that an area requires dewatering and the supervisor instructing them on how the situation will be managed.



HEA - Water Movement Permit

This Water Movement Permit must be carried by the water cart operator taking water, or site supervisor dewatering from any permanent or temporary basin. Once water movement has been completed, this permit must be returned to the Environment

Team. De-watering must be undertaken in accordance to the De-watering Work Procedure.

Date: Operator/Supervisor: Expected start Date: Time:

Expected completion Date: Time:

MU

ST

BE

CO

MP

LE

TE

D F

OR

AL

L W

AT

ER

MO

VE

ME

NT

Where from Basin ID: Extraction Point Permit Number (see over): Chainage: Other (describe):

What purpose Dewatering Dust suppression Other (describe):

If water is used for dust suppression no testing is required. If basin is being de-watered water must be tested and treated according to the De-watering Work Procedure.

Where to

Discharge point ID (Adjacent basin ID): Chainage:

Environment Officer instructions:

Environment Officer sign-off: Date:




APPENDIX C – PROPOSED SEDIMENT BASINS

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Project C = 0.5 Designed

Road Name I = 747.5 Date Designed

1I24hr = 3.52 Checked

Design 85 Date Checked

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F3 ramp 368828.82 6359953.03 N/A 0.4033 0.036 0.2 1.5 Minmi Creek

F3 ramp 368861.72 6360238.29 576 2.3113 0.036 1.1 8.6 Minmi Creek

F3 ramp 368904.07 6360238.29 487 1.2196 0.036 0.6 4.6 Minmi Creek

300 550 368797.84 6360410.91 392 1.185 0.036 0.6 4.4 Minmi Creek

550 950 368659.93 6360495.38 317 1.2637 0.036 0.6 4.7

950 1500 368318.08 6360680.71 689 1.9667 0.036 1.0 7.4

1500 2050 367312.23 6361007.56 330 1.7936 0.036 0.9 6.7

2050 2350 366954.51 6361207.26 129 1.1555 0.036 0.6 4.3

2350 3200 366723.86 6361257.31 574 2.304 0.036 1.1 8.6

3200 3600 366197.86 6361298.51 608 1.3253 0.036 0.6 5.0

3600 4200 365602.29 6362261.95 1320 2.4956 0.036 1.2 9.3

4200 4700 365555.6 6362639.57 308 0.9067 0.036 0.4 3.4

4700 5250 365226.75 6363031.95 498 1.4951 0.036 0.7 5.6 Surveyors Creek

5250 5550 364958.35 6363248 245 0.76 0.036 0.4 2.8 Surveyors Creek

5250 5550 364909.76 6363201.73 252 0.77 0.036 0.4 2.9 Surveyors Creek

5550 5650 364824 6363267.36 180 0.5885 0.039 0.3 2.2 Surveyors Creek

5650 5750 364759.07 6363324.43 239 0.333 0.039 0.2 1.2

5750 6250 364408.75 6363592.19 447 2.0142 0.039 1.0 7.5

6250 6820 364339.97 6363663.51 918 2.24 0.039 1.1 8.4

6820 7575 363744.24 6364776.34 99 0.204 0.039 0.1 0.8

7575 7750 363770.93 6364805.74 N/A 0.9796 0.039 0.5 3.7W7600

W6250

W5750

W6180

W5650

W7575

W5200

W4200

W600

W1000

W2000

W3200

W2650

W2450

Water Quality Basin

Name

W4700

W5550N

W5550S

W400

W150

W250

W300

Sedimentation Basins 30% Design

Catchment

ChainageDischarge Point

Comments


F11 Hunter Expressway

Annual Discharge Rates

Impervious Area

Mean Annual Rainfall in mm

1 Yr ARI 24 hr Storm in mm

Percentile

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Receiving Water

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Water Quality Basin

Name

Catchment

ChainageDischarge Point

CommentsReceiving Water

7750 363703.49 6365052.44 N/A 0.7932 0.039 0.4 3.0

8010 363442.12 6364981.53 1359 5.1865 0.039 2.5 19.4

8010 8450 363537.57 6365206.17 N/A 1.1173 0.039 0.5 4.2

8450 8600 363413.37 6365559.21 505 1.047 0.039 0.5 3.9

8600 8950 363317.56 6365739.64 343 1.7959 0.039 0.9 6.7

8950 9470 363142.2 6365992.39 660 2.7777 0.039 1.4 10.4

9470 10250 362169.06 6366748.92 2243 8.328 0.039 4.1 31.1 Surveyors Creek

10250 10350 362110.16 6366876.63 N/A 1.04 0.039 0.5 3.9 Surveyors Creek

ramp 362149.08 6366590.7 N/A 0.36 0.039 0.2 1.3 Surveyors Creek

10600 10750 361726.14 6366888.8 N/A 1.0074 0.039 0.5 3.8

10750 11150 361285.7 6367102.9 N/A 1.4619 0.039 0.7 5.5 Averys Creek

11150 11600 361180.94 6367115.17 737 3.0822 0.039 1.5 11.5 Averys Creek

11600 12050 360766.37 6367119.51 356 1.4406 0.039 0.7 5.4

12050 12600 360485.72 6367388.66 834 2.4945 0.039 1.2 9.3

12600 12900 359973.42 6368006.88 333 1.1075 0.048 0.5 4.1

W10200

W7875

W8010

W8450

W8650

W8930

W7870

W11650

W12050

W12900

W10350

RAB W10150

W10700

W11150

W11250

2 of 2




APPENDIX D – ACID SULFATE SOIL MANAGEMENT STRATEGY

Acid Sulfate Soil Management Strategy Seahampton to Kurri Kurri Section


0 23 March 2010

E Woodward T Doczy P Chatburn


ACID SULFATE SOIL MANAGEMENT STRATEGY

Acid Sulfate Soil Management Strategy Page 2

TABLE OF CONTENTS

1 INTRODUCTION ............................................................................................................................... 3

1.1 Potential Acid Sulfate Soils (PASS) ................................................................................................... 3 1.2 Actual Acid Sulfate Soils (AASS) ....................................................................................................... 3

2 POTENTIAL IMPACTS ..................................................................................................................... 4

2.1 Causes ............................................................................................................................................... 4 2.2 Effects ................................................................................................................................................ 4

3 IDENTIFICATION of ACID SULPHATE SOILS ............................................................................... 5

3.1 Step One: Visual Assessment ........................................................................................................... 7 3.2 Step Two: pH Field Test .................................................................................................................... 7 3.3 Step Three: Indicator Test ................................................................................................................. 7

3.3.1 Taking the sample .............................................................................................................. 7 3.3.2 Equipment Set Up .............................................................................................................. 8 3.3.3 The Indicator Test............................................................................................................... 8 3.3.4 Finalising the results ........................................................................................................... 8

4 TREATMENT ................................................................................................................................... 11

4.1 Treatment methodology one: ........................................................................................................... 11 4.2 Treatment methodology two: ........................................................................................................... 11

5 MONITORING .................................................................................................................................. 13

6 CONTINGENCY PROCEDURES .................................................................................................... 14

7 DISPOSAL ....................................................................................................................................... 15

7.1 Disposal of potential acid sulfate soils above the water table ......................................................... 16 7.2 Treatment of actual acid sulfate soils prior to disposal .................................................................... 16

APPENDICES

Appendix A - PASS/AASS Sample Sheet ............................................................................................. 17




1 INTRODUCTION

This management strategy has been developed in compliance with condition 139 of the Representatives Report for the Hunter Expressway Alliance (HEA), which states:

“Detailed soil testing must be undertaken in areas where acid-sulphate soils may occur, and a management strategy for excavation in acid-sulphate soils must be prepared and issued to contractors as part of construction documentation”.

Areas along the HEA route have been identified as containing potentially acid sulphate soils (Wallis and Fishery Creek). This Management Strategy has been prepared to minimise the risk of environmental damage caused by acid leachate. The Management Strategy applies to all construction activities and has been prepared in accordance with RTA Policy (RTA Procedure DEC - P04).The management strategy addresses the following:

• Identification of Acid Sulphate Soils (RTA Procedure DEC - P01)

• Assessment of the likely impacts of acid sulphate soils (RTA Procedure DEC - P02)

• Selection of treatments for acid sulphate soils (RTA Procedure DEC - P03)

Acid Sulfate Soils are the common name given to soils which contain iron sulfides. The process of acidification of the iron sulfides gives rise to two potentially environmentally damaging soil types:

1.1 Potential Acid Sulfate Soils (PASS)

The iron sulfides are contained in a layer of waterlogged soil. This layer can be clay, loam or sand, and is usually dark grey and soft. The water prevents oxygen in the air reacting with the iron sulfides. This layer has the potential to oxidise to sulfuric acid once exposed to air.

1.2 Actual Acid Sulfate Soils (AASS)

When the iron sulfides are exposed to air and produce sulfuric acid, they are known as actual acid sulfate soils. While soil itself can neutralise some of the sulfuric acid, the remaining acid moves through the soil, acidifying soil water, groundwater and surface waters.

Drainage of water and excavation can expose PASS to the air, causing AASS. Therefore, it is important to quickly identify and control both PASS and AASS to prevent significant environmental damage. If you are working in an area of PASS please become familiar with the testing and associated mitigation measures.

.




2 POTENTIAL IMPACTS

2.1 Causes

The following are a list of possible causes of impacts of road construction on sediments containing PASS materials.

1. Excavation of PASS material. Oxidation of this material can result in acid leachate.

2. Discharge of sub-surface water as a result of settlement producing acid leachate where it flows through oxidised AASS.

3. Embankment settlement will depress the underlying material with respect to the water table. In some circumstances heave at the toe of the embankment by displacement may raise PASS material above the water table.

4. Oxidation of pyrite in imported fill material.

2.2 Effects

Should any of the above causes eventuate, the following impacts may result:

• toxifying nearby soil by stripping essential elements and/or dissolving heavy metals

• reducing farm productivity and altering natural vegetation communities

• damage to infrastructure

• death or stunted growth of aquatic flora and fauna

• large scale fish kills and fish disease

• impact on aquaculture

• mass mortalities of microscopic organisms

• increased light penetration due to water clarity

• loss of acid-sensitive crustaceans

• destruction of fish eggs

• loss of habitat

• persistent iron coatings

• alterations to water plant communities

• invasion by acid-tolerant water plants

• reduced spawning success due to stress

• chemical migration barriers

• reduced food resources

• dominance of acid-tolerant plankton species

• changes in food chain and web

• reduced recruitment

• higher water temperatures due to increased light penetration

• increased availability of toxic elements

• reduced availability of nutrients




3 IDENTIFICATION OF ACID SULPHATE SOILS

The following procedures have been developed to determine whether the soils contain pyrite (FeS2) to levels where they could be classed as acid sulfate soil, thus requiring treatment. It has been developed based on information provided in the NSW ASSMAC guidelines (1998), and the draft Identification and Investigation of Acid Sulphate Soils guideline (2006) prepared by the WA Department of Environment.

Use the following flow chart to assist in the identification process.

Please note: information provided by Maitland City Council indicates that potential disturbance to acid sulphate soils may occur within the Alliance section of works when working at Wallis and Fishery Creek.




Visual Assessment:

Reference Environmentally Sensitive Area Maps. Inspect for odour and colour which may indicate

Potential Acid Sulphate Soil

pH Field Test:

Use field pH kit to test pH.

pH > 5.5:

No Actual Acid Sulphate Soil.

pH <5.5:

Potential Acid Sulphate Soil. Take a sample iand keep frozen until Indicator test can be

undertaken.

Conduct Indicator Test:

Environment staff to conduct indicator test to confirm Actual Acid Sulphate Soil

No response to Indicator Test:

No Acid Sulphate Soil. No further action required

Sample responds to Indicator Test:

Send sample to lab for verification of Acid Sulphate Soil




3.1 Step One: Visual Assessment

Visual assessment of PASS or AASS begins using the Environmentally Sensitive Area Maps, which identify all areas of PASS. If working in an area of PASS vigilant visual monitoring should be undertaken during all stockpiling and excavation activities.

It is also important to be able to recognise indicators of actual acid sulfate soils to prevent further acidification of land and waterways. These indicators include:

• cloudy green-blue water

• excessively clear water

• iron stains

• poor pasture

• scalded soil

• yellow jarosite

• ‘rotten egg’ smell

• waterlogged soil

• corrosion of concrete and/or steel structures

• oily-looking surface iron bacterial scum

• dark grey soils (see Figure 2 )

3.2 Step Two: pH Field Test

1. Place a small amount of soil (approx. 5-15 grams) in a beaker

2. Add distilled water to make up a soil :water paste

3. Use either a soil pH test kit or pH meter to ascertain pH value.

Field pH readings of 4 or less, indicate that actual acid sulfate soils are present with sulfides having been oxidised in the past, resulting in acid soils and acidic soil pore water. Readings greater than 4 but less than 5.5 are acid and may be the result of some previous or limited oxidation of sulfides, but is not confirmatory of actual acid sulfate soils; therefore an indicator test is required.

It should be noted that substantial exchangeable/soluble aluminium and hydrogen ions usually exist at these pH values. Other factors such as excessive fertilizer use, organic acids or strong leaching can cause pH values greater than 4 but less than 5.5.

3.3 Step Three: Indicator Test

The Indicator Test measures the existing acidity of a soil/water paste, and is therefore used to help identify AASS.

3.3.1 Taking the sample

1. Visually assess the soil for colour, texture, vegetation, porosity etc. Write down the description along with the soil location, depth, date, time and sample number onto results sheet, and onto the sampling container.




2. If you see a yellow jarosite component aim for that in your sample, otherwise, take a representative samples either in an airtight plastic bag or soil jar.

Note; freezing the sample prevents oxidisation but it is best to use samples which have been thawed; therefore if testing is not to be undertaken immediately, freeze samples.

3.3.2 Equipment Set Up

1. Clean the probe with Methylates Spirits or if it has been left for a long time, clean initially with weak hydrochloric acid (HCl) before repeating with Methylates Spirits.

Note: the equipment used for this test may vary, please follow calibration and maintenance instructions recommended by the equipment manufacturer.

2. Calibrate the temperature probe using a standard thermometer.

3. ‘Wash’ the pH probe with pH 4 wash solution then immerse in pH 4 to calibrate.

4. To calibrate the probe; press CAL button, “not ready” should start flashing, when this stops flashing press CFM button to adjust calibration to pH 4.

5. Follow the previous 2 steps using pH 7 buffer, to calibrate to pH 7.

3.3.3 The Indicator Test

1. Place a small amount of soil (approx. 15 grams) in two heat resistant beakers (one shall be used as a control)

Note: The control and test samples should be subsets of the same sample and be as similar in constitution as possible.

2. Cover the Control sample in distilled water and the Test sample with 50% hydrogen peroxide (H2O2) and observe the reactions, make notes on reaction intensity, speed and temperature changes. To increase reaction, place test sample in the sun/near heat. Note: Please undertake this in a very well ventilated area.

3. The reaction should be observed and rated. Continue to observe the reaction until it is complete; from 20 mins to 24 hours. Greater reaction indicates that the soil sample was more likely to have a lower pH, i.e.; super foamy reaction expects a pH of about 2.

4. While the Test sample is reacting, take the pH reading for the Control sample.

5. When reaction of test sample is complete, take pH of the solution. If required add distilled water to increase volume of solution in order to cover the pH probe.

Note: The handling and storage of H2O2 is an OH&S issue and must be managed in accordance with relevant regulations and the MSDS. Conduct this test is a well ventilated area

3.3.4 Finalising the results

1. Write all observations and results onto Results Sheet (included in Appendix One).

All soil samples taken MUST be recorded on the Results Sheet irrelevant of level of testing undertaken and left with the Environment Team staff for reporting purposes.




Potentially positive reactions include one or more of the following:

• change in colour of the soil from grey tones to brown tones;

• the release of sulphurous odours;

• a substantial depression in pH below that of “actual” acid sulfate soils (pH 4 or less); and

• pH of less than 3.

The strength of the reaction is a useful indicator. The test is most useful and reliable with clays and loams containing low levels of organic matter. It is least useful on coffee rock, sands, or gravels, particularly dredged sands with low levels of sulfidic material (<0.05 percent S). With soils containing high organic matter (e.g. surface soils, peat, mangrove/estuarine mud and marine clays), care must be taken when interpreting the reaction as high levels of organic matter and other soil constituents particularly manganese oxides can also cause a reaction.

The following table provides information for interpretation of Control pH results:

pH value Result Comments

pH Control ≤4

Actual acid sulfate soils

(AASS) indicating oxidation of sulfides

This is generally not conclusive because

highly organic soils such as peats and occasionally heavily fertilised soils may also give pHF ≤4.

pH Control ≤3.7

Expected if jarosite exists in

the sample

This is also an AASS. Jarosite needs a pH of at least 3.7 to form. Horizons containing some jarosite and some other mottling (iron, grey) may have a pH >3.7 if the sample contains a mixture of jarosite and higher pH soil. This depends on the level of oxidation and the ability of the soil to ‘hold’ the acid.

pH Control >7

Expected in waterlogged,

unoxidised, or poorly drained

soils

Marine muds commonly have a pH >7 and this reflects seawater (pH 8.2) influence. May be a

PASS after oxidation with H2O2 .

4 < pH Control ≤5.5 An acid soil Investigate further for possible ASS link, e.g.

AASS with shell presence.

A combination of the following three factors is considered in arriving at a ‘positive’ identification of AASS:

a) A reaction with hydrogen peroxide - the strength of the reaction with peroxide is a useful indicator but cannot be used alone. Organic matter, coffee rock and other soil constituents such as manganese oxides can also cause a reaction. Care should be exercised in interpreting a reaction on surface soils and high organic matter soils such as peat and coffee rock, and some mangrove/estuarine mud and marine clays. This reaction should be rated, e.g.

L = Low reaction,

M = Medium reaction,




H = High reaction,

V = volcanic reaction,

X = Extreme reaction (very vigorous, gas evolution and heat generation)

b) The actual value of pHFOX (i.e. Hydrogen peroxide/soil solution in the Test sample after the reaction has finalised). If pHFOX <3, and a significant reaction occurred, then it strongly indicates a PASS. The more the pHFOX drops below 3, the more positive the presence of inorganic sulfides.

c) A much lower pHFOX than Control sample pH - The lower the final pHFOX value and the greater the difference between the pHFOX compared to the Control pH, the more indicative the presence of PASS. This difference may not be as great if starting with an already very acid pH (close to 4), but if the starting pH is neutral or alkaline then a larger change in pH should be expected. Where fine shell, coral or carbonate is present the change in pH may not be as large due to buffering. The ‘fizz test’ (effervescence with 1 M HCl) should be used to test for carbonates and shell.

Of these three factors, the final pHFOX value is the most conclusive indicator, and the lower the final pHFOX, the more confident one can be that PASS may be present.

2. Send off all samples with a significant pH drop between control and test samples, a very low pH, or a very strong/fast reaction with the Hydrogen peroxide.

All soil samples must remain frozen until Indicator Test, and if required subsequent lab analysis, is performed.

3. Keep probe moist when not in use, store in its cap with a touch of HCl.

Note: follow manufacturer’s maintenance instructions for the equipment you are using.




4 TREATMENT

Estimate the potential amount of soil that may be disturbed and determine a treatment area large enough to contain all excavated PASS or AASS. Treatment areas shall meet the following requirements:

a) Be located at least 50m from waterways

b) Be constructed with impervious clay bunds to prevent leachate runoff.

c) Be lined with agricultural lime on the floor of the treatment area.

The treatment area will require a settlement pond or sump to collect any runoff. The pond or sump must be designed to capture the PASS treatment area runoff a 1 in 10 year (1 hour) storm event.

4.1 Treatment methodology one:

Soil shall be laid in 300mm layers and treated with lime. The soil shall be turned over/ mixed to ensure adequate mixing. Surface applications of lime shall be applied to the treatment area at a rate capable of neutralising all acid waters that might infiltrate through PASS/AASS, prior to placing PASS/AASS in the treatment areas. The minimum application rate should be equivalent to no less than 50t of fine agricultural lime/ha (or 5kg fine agricultural lime/m2, or 20kg/m3). This application may need to be increased depending on stockpile height and actual and potential acidity of the AASS.

Note: Refer to laboratory results and recommendations for final dosing rates.

4.2 Treatment methodology two:

Where the rate required is below 2kg/m3 the material will not be treated but will be stockpiled for later use as topsoil for the works.

Where the dose rates are between 2kg/m3 and 10kg/m3, agricultural lime will spread over the area at the required rate and tyned in prior to excavation and stockpiling of the material. The base of the stockpile site will be lined with lime at 0.5kg/m2 to neutralise any water that may seep into the ground water. A sump hole will be excavated near the stockpile to enable runoff to be captured and tested to confirm the water quality leaving the material. The topsoil material will then be used in topsoiling the works.

Where the dose rates are above 10kg/m3, the material to be excavated will be separated based on its acid potential and stockpiled in a bunded area on a bed of lime at 1.0 kg/m2. This material will then be tested to confirm the appropriate dose rate and treated accordingly. A sump will be provided within the bunded area to allow the runoff to be checked for conformance. This material shall remain bunded until test results available. The stockpile will then have the additional lime added if required. After treatment, this material can then be placed in mounds for landscaping purposes compacted and covered with a minimum of 500mm of non PASS material or used to backfill piles and pile caps.




Figure 3: Example of an AASS treatment area.




5 MONITORING

A programme of regular water quality monitoring will be established involving monitoring of the water within creeks and rivers adjacent to construction. Random checking of the pH of excavated materials will be carried out on site. Additional testing will be arranged if pH levels are below background values.

Where surface water and/or leachate collects within the bunded treatment area, the water shall be tested for pH, turbidity and TSS values prior to discharge or pumped directly to a sedimentation basin. Should pH results be lower than 5, further treatment may be required.

Any runoff or fines collected in the settlement pond/sump will require assessment prior to decommissioning of the stockpile area.

Regular visual monitoring of PASS/AASS areas and surrounds shall be undertaken to identify signs of ASS oxidation. This monitoring should include detecting:

• Unexplained scalding, degradation or death of surrounding vegetation;

• Unexplained death or disease in aquatic organisms

• Formation of the mineral jarosite and other acidic salts in exposed or excavated soils

• Areas of green-blue water or extremely clear water indicating high concentrations of aluminium

• Rust coloured deposits on plants and on the banks of drains, water bodies and watercourses indicating iron precipitates

• Black to very coloured waters indicating de-oxygenation

Final validation sampling of treated soils will be conducted at the completion of treatment to determine if the neutralisation process has been successful. Validation sampling will be conducted in accordance with the Acid Sulfate Soil Manual (ASSMAC, 1998).




6 CONTINGENCY PROCEDURES

If PASS is suspected, appropriate actions must be taken to ensure the PASS is not able to oxidise in the field. For example:

• If PASS is shown to occur in the vicinity of your work area, choose a construction method that avoids the need to disturb PASS.

• If avoidance of PASS is not possible, notify environment staff of upcoming works at least 5 days prior to commencement of activities.

Any material that does not conform to the expected or tested levels and exhibits a high PASS will be either left in place, or if already excavated will be isolated and a suitable treatment method devised. Although experience has shown that any potential pollution does take time to develop close monitoring will be carried out until suitably treated. If a serious situation does develop in the interim immediate treatment with lime will be carried out. If PASS is suspected, appropriate actions must be taken to ensure the PASS is not able to oxidise in the field.




7 DISPOSAL

Once treatment has occurred, onsite re-use and/or disposal of the treated soil shall be undertaken. Testing of soil Ph shall be carried out by the Environment Team prior to reuse onsite. This material can be placed in mounds, extended batters or for landscaping purposes, compacted and covered with a minimum of 500mm of non PASS material or used to backfill piles and pile caps.

If off-site disposal is required, procedures outlined within the document Waste Classification Guidelines, Part 4: Acid Sulphate Soils (DECCW 2008) shall be implemented.

This includes the following:

• Keep potential ASS wet at all times during excavation and subsequent handling, transport and storage until they can be disposed of safely.

• ASS must be received at the proposed disposal point within 16 hours of being dug up.

• Potential ASS may be disposed of in water below the permanent water table, provided:

this occurs before they have had a chance to oxidise, i.e. within 24 hours of excavation

they meet the definition of ‘virgin excavated natural material’ (VENM) under the Protection of the Environment Operations Act 1997, even though they contain sulfidicores or soils.

• Landfills shall be licensed by DECC to dispose of potential ASS below the water table.

• DECC’s Environment Line has details on facilities able to accept this waste: phone 131 555.

• Potential ASS must be disposed of within 8 hours of their receipt at a landfill and kept wet at all times until their burial at least 2 metres below the lowest historical level of the water table at the disposal site.

• Documentation must be provided to the occupier of the landfill for each truckload of potential ASS received, indicating that the soil’s excavation, transport and handling have been in accordance with the Acid Sulfate Soil Manual, thus preventing the generation of acid.

• The occupier of the disposal site must also test the pH of each load of soil received immediately prior to its placement under water using the test method(s) in the Acid Sulfate Soil Manual (Methods 21A and/or 21Af). These details, together with the pH of the soil recorded at the time of its extraction, must be retained by the occupier of the landfill site.

• The disposal site’s licence will outline what documentation needs to be kept and for how long.

• Soil that has dried out, undergone any oxidation of its sulfidic minerals, or which has a pH of less than 5.5 must be treated by neutralisation and disposed of at a landfill that can lawfully accept it (see ‘Disposal of actual acid sulfate soils’ below).

• The pH of the water at the landfill into which the potential ASS is placed must not be less than 6.0 at any time. Landfill licence conditions require the occupiers of potential ASS disposal sites to regularly monitor the pH of ground and surface waters at their premises.




7.1 Disposal of potential acid sulfate soils above the water table

• Where potential ASS cannot be classified as VENM or a suitable underwater disposal site at a landfill is not available, the soil must be treated in accordance with the neutralising techniques in the Acid Sulfate Soil Manual. After treatment the soil should be chemically assessed in accordance with Step 5 in Part 1 of the Waste Classification Guidelines, available at www.environment.nsw.gov.au/waste/envguidlns. This will determine whether any other contaminants are present in the material. When the classification has been established, the soil should be disposed of to a landfill that can lawfully accept that class of waste.

• Actual ASS contain highly acidic soil horizons or layers resulting from the aeration of soil materials that are rich in iron sulfides, primarily sulfide. This oxidation produces more hydrogen ions than the sediment is able to neutralise, resulting in soils with a pH of 5.5 or less when measured in dry season conditions. These soils can usually be identified by the presence of pale yellow mottles and coatings of jarosite.

7.2 Treatment of actual acid sulfate soils prior to disposal

• Actual ASS must be treated by the generator of the waste before they can be considered for disposal. Treatment should be in accordance with the neutralising techniques outlined in the Acid Sulfate Soil Manual.

• Following neutralisation, the generator of the waste must chemically assess the soil in accordance with Step 5 of the Waste Classification Guidelines: Part 1 – Classifying waste

• (available at www.environment.nsw.gov.au/waste/envguidlns). This will determine whether there are any other contaminants that may affect how the waste is classified for disposal.

• Once classified, the waste must be taken to a landfill licensed to accept that class of waste.

• Prior arrangements should be made with the occupier of the landfill to ensure that it is licensed to accept the waste. The landfill should be informed that the actual ASS has been treated in accordance with the neutralising techniques outlined in the Acid Sulfate Soil Manual and that the waste has also been classified in accordance with Part 1 of the Waste Classification Guidelines.

(Source Document: Waste Classification Guidelines, Part 4: Acid Sulphate Soils (DECCW 2008)




Appendix A - PASS/AASS Sample Sheet

Combined field description and ASS data

Sample ID Soil Description (e.g. clay, silt, sand, colour)

pH Control pH Test pH Control - pH Test

Reaction Rate Temp.

Sent for testing

pH units pH units pH units L,M,H,X,V 0C YES/NO

#This reaction should be rated, e.g. L = Low reaction, M = Medium reaction, H = High reaction, X = Extreme reaction, V = volcanic reaction.




APPENDIX E – AFFLUX PRELIMINARY IMPACT ASSESSMENT



Water Input to Soil-Sed-Erosion Plan - CoA 93oA 93 Page 1

APPENDIX D – AFFLUX PRELIMINARY IMPACT ASSESSMENT (LOCAL AND REGIONAL)


00 11-5-10 Terry Swanson Howard Chemney



Water Input to Soil-Sed-Erosion Plan - CoA 93oA 93 Page 2

SCOPE

This appendix reviews the afflux impacts upstream and downstream of cross-drainage culverts and bridges that form part of the Hunter Expressway Alliance Project (the Project). The appendix also considers the impacts of the motorway embankment in a regional flooding context.

This Soil and Water Management Sub Plan forms part of the Construction Environmental Management Plan (CEMP) for the Hunter Expressway, National Highway Link. This appendix has been developed in response to Condition of Approval No. 93 which requires the following::

93 . The Soil and Water Management Sub Plan shall identify mitigation measures proposed to be taken to address any:

i. Afflux impacts from the roadway or structures associated with the proposal eg. The proposed Wallis/Surveyors Creek crossing and impacts upstream in the Buchanan area; and

ii. Adverse impacts from the proposal as a result of losses to the Hunter River floodplain storage area for flood events above and including the 1% Annual Exceedence Probability Event eg. The Wentworth and Dagworth Swamps.

AFFLUX IMPACTS - METHODOLOGY

Calculation Methods

The cross drainage design will include hydraulic calculations for watercourses that are crossed by the HEA works to determine flooding and impacts.

The flows in the watercourses crossing the motorway will be determined and verified using a mixture of hydrological methods as follows:

Existing Flood Studies

XP-RAFTS (Catchment Specific)

Flow Rating Curve (derived from XP-RAFTS)

Rational Method (Rural)

The sizing of the watercourse crossing structures for the motorway will be determined and verified using a mixture of hydraulic methods as follows:

RMA-2 Two Dimensional Flood Model

HEC-RAS One Dimensional Flood Model

Excel Spreadsheet – Waterway Design Guide Methods

Design Events

Culverts will be sized for the design events as set out in Table D1.

Table D1.

Cross Drainage Element Design Events Refer Note

Culvert Crossing the Motorway 50,100 1,2

Bridge Crossing the Motorway 100, 2000, PMF 3,4

Culvert Crossing a Local Road or Motorway Access Ramp

20,50,100 1,2

Bridge Crossing a Local Road or Motorway Access Ramp

20,50,100, 2000,PMF

1,3,4

Culvert Crossing Private Access Track 1 2

Notes:

1. Selected design event will be dependent upon the identified afflux acceptability

2. An overland flowpath review will be undertaken to assess the impacts of a blockage where culverts (pipe or box) form the cross-drainage element.

3. A structural adequacy assessment will be undertaken using the 1 in 2000 year flood event.

4. An overland flowpath review will be undertaken for the probable maximum flood (PMF) event.

In addition to the above design events a number of additional events including the 1, 5, 10 year flood events will also be assessed to demonstrate no detrimental impacts.

In order to provide a hydrological/hydraulic approach that ensures an assessment of the motorway work impacts only, the following catchment scenarios will be modelled:

Baseline – the baseline catchments will be based on the 2010 level of development as determined from the Cessnock/Maitland Council LEP’s and aerial photography.

Post – Development - the post development catchment will be based on the 2010 level of development as determined for the baseline with the addition of any motorway works. Any changes to catchment areas, connectivity or runoff potential will be reflected.

Ultimate - the ultimate development catchment will be determined on the 2115 level of development as set out in the Cessnock/Maitland Council LEP’s and include the motorway works. Any changes to catchment areas, connectivity or runoff potential will be reflected.

Therefore for purposes of assessing the impacts of the motorway a comparison of flood levels and other flood data will be undertaken using the Baseline and Post-Development scenarios.

For purposes of confirming the motorway has 100yr flood immunity during its design life an assessment of flood levels and other flood data will be undertaken using the Ultimate scenario.

Afflux Acceptability Criteria

The cross drainage infrastructure will be designed to prevent damage or not worsen impacts (i.e. where existing impact identified) to existing property and infrastructure.

An afflux acceptability assessment will be undertaken for each culvert and bridge location. The level of sensitivity of the design solution to afflux will be based on a localised risk assessment that considers the following as a minimum:

i. land ownership/usage/zoning

ii. proximity of sensitive property or infrastructure

iii. material and immaterial loss to private or public property and infrastructure

iv. potential for negative environmental impacts

v. impacts on motorway embankment

vi. impacts on local road embankment and road overtopping

vii. overland flowpath potential

viii. public safety

Table D2. summarises the target and absolute afflux limits to be set in the assessment of the impacts of the motorway on waterways crossed.

Table D2.

Assessed Sensitivity

Target (mm)

Absolute (mm)

Comment

High 0 +10mm To be used where any material loss to property/infrastructure potentially occurs. To be used where impacts to the environment, public safety or motorway /local road operation are highly undesirable or cannot be satisfactorily mitigated against.

Medium 0 +50mm To be used where immaterial loss property/infrastructure potentially occurs. To be used where impacts to the environment, public safety or motorway /local road operation are moderately undesirable or where

satisfactory mitigation can be provided.

Low 0 Varies but generally >50mm

To be used where no material or immaterial loss potentially occurs. To be used where impacts to the environment, public safety or motorway /local road operation are minor and where no mitigation is required.

None N/A N/A To be used where afflux impacts are wholly contained with land within the RTA’s ownership

Note:

High Sensitivity – this will generally occur where flooding of a private property (above floor flooding) or key infrastructure (ie substation) is impacted. This will also occur where sensitive environments or key amenity facilities are impacted. Flooding afflux that can result in more local road closure (or more frequent) or unacceptable exposure of the motorway embankments to water surcharge/wetting.

Medium Sensitivity – this will generally occur where flooding of a private property/field outside the habitable areas is impacted and land use or access may be impacted. Localised mitigation treatment may be provided to reduce any impacts of the flooding. Subject to potential negotiation and agreement with some affected landowners this may be reclassified to a low sensitivity.

Low Sensitivity – this will generally occur where flooding of a private property/field outside the habitable areas is impacted. Localised mitigation treatment may be provided to reduce any impacts of the flooding.

None - this will generally represent land located within the HEA boundary or fields/forest owned by the RTA or State Government. Subject to potential negotiation and agreement with some affected landowners (if any), private fields may be reclassified to this sensitivity.

AFFLUX IMPACTS - ASSESSMENT

A preliminary assessment of afflux impacts has been undertaken using the Rural Rational Method hydrology and culvert inlet and outlet control hydraulic calculations. A number of the bridge crossings have been modelled using RMA-2 or HEC-RAS. The afflux acceptability criteria has been applied to the afflux results and upstream and downstream mitigation recommended where required.

Table D3. contains this assessment.

The assessment generally confirms that afflux impacts for the majority of culverts and bridge crossings are generally limited and either restricted to land within RTA ownership or areas of grazing/woodland.

The afflux impacts around the Wallis/Surveyors Creek and nearby Buchannan area are also generally limited to land within the RTA ownership. While a minor increase in flood level of 20mm is currently predicted to an individual habitable property (Mr J R & Mrs. M E & Ms. T M Hooley) this will be reduced at least to the absolute level requirement (+10mm) as part of the detailed design. It is expected that only minor changes to the bridge openings and spill through batters would be required to achieve this.

REGIONAL FLOOD IMPACTS

A preliminary draft report of the “Hunter River: Branxton to Green Rocks Flood Study was provided to the HEA. A full review of this report was undertaken and key points to note are as follows:

Modelling has been undertaken using a 2D flow model (TUFLOW) A 36 hour duration event was used to produce peak design flows The Hunter River has a catchment area of some 15600km2 upstream of Maitland A number of significant flood events have occurred on the Hunter River including the

flood events of 1955, 1971,1977 and 2007 which were used for calibration The timing of flows from a number of tributaries including Wallis Creek can have a

significant impact on flood levels associated with low areas of these creek systems as the flood plain areas can fill in advance of the main Hunter River peak.

The HEA motorway embankment and realigned John Booth Drive and George Booth Drive road embankments will be built out into the Wallis/Surveyors Creek floodplain. The embankment footprint area of some 0.25 km² represents a negligible percentage of the Hunter River regional flood footprint. The impact of the loss of flood storage in a regional context is negligible.

Regional flood events impacting on Wallis Creek will occur as local storage (river-locking) and backwater from the Hunter River as flood flows overtop the existing flood levees. The timescale of such an event is measured in days rather than hours and therefore the flood mechanism is controlled by volumetric constraints (i.e. a big pond) rather than backwater conveyance at particular structures (unless these are particularly constrictive).

The George Booth Drive and John Renshaw Drive bridge/culvert structures are to be reconstructed with a similar waterway area to the existing structures and therefore no impacts to regional backwater conveyance is expected.

The HEA motorway bridge opening of 176m results in a minor local afflux of some 300mm for the 100yr peak local flood event and therefore is not considered to represent a meaningful constriction to flow in a regional context. Therefore no impacts to regional backwater conveyance and flood flow balancing are expected in the Buchannan area.

HW (RL)HW

Depth (m)

AFFLUX (approx)

(M)

Land ownership upstream of Culvert/Bridge Location

Property Impact Type

Environment Impact

Public Safety

Impact Sensitivity Mitigation/Comment

Land ownership downstream of Culvert

LocationDownstream Issues Mitigation/Comment

C0016SRa 46.20 3.39 2.44 RTA Woodland Low Low None No mitigation required from cross drainage RTA None No mitigation required from cross drainage

C0020SR 56.98 0.58 0.39 RTA Woodland Low Low None No mitigation required from cross drainage RTA None No mitigation required from cross drainage

C0025SR 50.60 0.28 0.17 RTA Woodland Low Low None No mitigation required from cross drainage RTA None No mitigation required from cross drainage

BW06, BW07a, BW07b,

N/A N/A 0.00 RTA Woodland, Heritage Low Low None Bridge structures have clear span over Minmi Creek RTA None No mitigation required from cross drainage

C0054 41.48 4.12 3.18 Coal & Allied Woodland Low Low Low

Increased flood level is contained in Bush Land with minimal impact. An alternative arch culvert solution is also being considered here subject to structural and cost review.

Coal & Allied None No mitigation required from cross drainage.

C0082 64.31 1.81 1.75 Coal & Allied Woodland Low Low None No mitigation required from cross drainage Coal & AlliedExisting survey detail suggests no defined channel downstream.

Flow spreader to be utilised to return culvert outlet flow to sheet flow

C0096 72.42 1.37 1.30 Coal & Allied Woodland Low Low None No mitigation required from cross drainage Coal & AlliedExisting survey detail suggests no defined channel downstream.


BW09 (TWIN) N/A N/A 0.00 RTA Woodland Low Low NoneViaduct 1 structure has clear span over local watercourse

RTA None No mitigation required from cross drainage

BW10 (TWIN) N/A N/A Minor RTA Woodland Low Low NoneViaduct 2 structure has clear span over local watercourse with minor pier encroachment for larger events


BW11 (TWIN) N/A N/A Minor RTA Woodland, Heritage Low Low NoneViaduct 3 structure has clear span over local watercourse with minor pier encroachment for larger events. Existing Burrenjim Dam unaffected by afflux


C0282 66.42 2.01 1.83 Coal & Allied Woodland Low Low None No mitigation required from cross drainage Coal & Allied Discharges direct to Bluegum Creek - No issues No mitigation required from cross drainage

C0287 65.98 2.29 2.02 Coal & Allied Woodland Low Low None No mitigation required from cross drainage Coal & Allied Discharges direct to Bluegum Creek - No issues No mitigation required from cross drainage

C0324 79.69 2.39 2.31 Coal & Allied Woodland Low Low None No mitigation required from cross drainage Coal & Allied None No mitigation required from cross drainage


C0388 77.87 1.20 0.97 Coal & Allied Woodland Low Low None No mitigation required from cross drainage Coal & AlliedConcrete channel required downstream to return flow to natural channel

No mitigation required from cross drainage

C0408 61.24 1.53 1.35 Coal & Allied Woodland Low Low None No mitigation required from cross drainage Coal & Allied No mitigation required from cross drainage No mitigation required from cross drainage

C0436SR 56.45 0.56 0.14 Coal & AlliedWoodland and Landowner Access

Low Medium Medium

Culvert designed to pass 1:20 year storm. Detailed design to ensure the current level of flood immunity for the Daracon Access road is maintained. See C0446 also.

Coal & Allied None No mitigation required from cross drainage

C0446 48.74 2.24 1.10 Coal & Allied Woodland Low Low Medium

The 100 year backwater from culvert C0446 does not overtop the Daracon Access road but the backwater may affect the current capacity of the Daracon Access culverts. Detailed design to ensure the current level of flood immunity for the Daracon Access road is maintained.

Coal & Allied None No mitigation required from cross drainage

C0522 44.67 1.49 0.77 Coal & Allied Woodland Low Low None No mitigation required from cross drainage Coal & Allied Existing survey detail suggests no defined channel downstream.


BW13 N/A N/A N/A Coal & Allied Woodland Low Low None No mitigation required from cross drainage Coal & Allied Channel realignment to join to existing channel No mitigation required from cross drainage


C0585 37.08 1.33 1.13 Coal & Allied Woodland Low Low None No mitigation required from cross drainage Coal & Allied Existing survey detail suggests no defined channel downstream.


C0624 35.91 3.41 3.03 Mindaribba LALC Woodland Low Low None No mitigation required from cross drainage Mindaribba LALC Existing survey detail suggests no defined channel downstream.


C0732 25.34 3.34 2.83 Mindaribba LALCGrazing (D/S), Woodland (U/S)

Low Low LowHW located over RTA project boundary but is located in undeveloped bushland. No mitigation required from cross drainage

Mrs. M J HolmesNo defined Channel downstream culvert concentrates flow


C0749 27.56 1.83 1.70Mindaribba LALC/County Property holdings

Grazing Low Low None No mitigation required from cross drainage Tp & Mj Holmes pty Ltd.No defined Channel downstream culvert concentrates flow


C0766 30.18 1.45 1.25 County Property holdings Grazing Low Low None No mitigation required from cross drainage Tp & Mj Holmes pty Ltd.No defined Channel downstream culvert concentrates flow


100YR ARI EVENT UPSTREAM AFFLUX ASSESSMENT 100YR ARI EVENT DOWNSTREAM AFFLUX ASSESSMENT

C0789 24.55 1.68 1.37 Tp & Mj Holmes pty Ltd. Grazing Low Low None No mitigation required from cross drainage Tp & Mj Holmes pty Ltd. None None

C0789SR 22.68 1.95 1.62 Tp & Mj Holmes pty Ltd. Grazing Low Low None No mitigation required from cross drainage Tp & Mj Holmes pty Ltd. No defined Channel downstream culvert concentrates flow


C0806 21.96 1.06 0.88 Tp & Mj Holmes pty Ltd. Grazing Low Low None No mitigation required from cross drainage Tp & Mj Holmes pty Ltd. No defined Channel downstream culvert concentrates flow


C0858 16.46 1.82 1.61 Tp & Mj Holmes pty Ltd. Grazing Low Low Low

HW located over RTA project boundary but is located semi cleared grazing land with minimal impact expected for more frequent flood events. No mitigation required from cross drainage

Tp & Mj Holmes pty Ltd.No defined Channel downstream culvert concentrates flow


C0895 20.35 2.59 2.32 Tp & Mj Holmes pty Ltd. Grazing Low Low Low

HW located over RTA project boundary but is located semi cleared grazing land with minimal impact expected for more frequent flood events. No mitigation required from cross drainage

Tp & Mj Holmes pty Ltd.

No defined Channel downstream culvert concentrates flow. Diverted catchments from U/S of the Buchannon Motorway cut to this location will increase flow.

Flow spreader to be utilised to return culvert outlet flow to sheet flow. Flows will pass through some 150m of grazing land before entering Surveyors Creek. A farm dam low lying marsh areas are located along this route. Increased flow are likely to benefit farm dam with low impact on grazing zone. No mitigation required from cross drainage.

C0978 28.63 2.68 2.38 Tp & Mj Holmes pty Ltd. Woodland Low Low None No mitigation required from cross drainage Tp & Mj Holmes pty Ltd.No defined Channel downstream culvert concentrates flow.

Additional Survey may show defined channel.

C1013SRa N/A N/A Minor Tp & Mj Holmes pty Ltd. Grazing Low Low Low

Existing culvert to be replaced with like to ensure no increase in flow downstream to property access. A minor increase in catchment area draining to this culvert will occur as a result of the road realignment. A minor HW increase may occur and extend beyond the RTA project boundary, however the impact is likely to be mimimal, affecting an existing low area used to store water for grazing. No mitigation required from cross drainage

Mrs. C I & Mr. L L Beveridge

No defined channel downstream and culvert potentially concentrates flow. Flow path currently crosses landowners access track. No existing culvert under landowners track

Confirm that landowner will formalise pipe under their final track (currently temporary). Flow spreader to be utilised to return culvert outlet flow to sheet flow

C1013SRb 15.56 0.76 0.68 RTA Woodland Low Low None No mitigation required from cross drainage RTA None No mitigation required from cross drainage

BW170.2m (Smith), 0.2- 1.0m (RTA)

RTA & Mr M L & Mrs. B M Smith

Grazing Low LowMeduim (Smith), None (RTA)

Afflux impacts on a small area of the Smith property and is considered minimum as the affected area consist of a farm dam and immediate surrounds. The detailed design and flood modelling will review the Wallis/Surveyors Creek motorway bridges and cross-drainage with view to reducing this impact. Afflux impacts contained within RTA land ownership are acceptable.

Mrs. C D ShearmanSlight impact from AFFLUX, but not measurable (<0.01m)


BW19

0.01 -0.03 (0.02 at Hooley House)

Mrs. M M Percival, Mr C R & Mrs. L Parker, Mr J R & Mrs. M E & Ms. T M Hooley

Grazing Low LowHigh (Hooley) Low(Others)

Afflux impacts occur on these upstream properties which are already significantly flood impacted by the existing 100yr flooding. The Hooley property contains a house which is already innundated to a significant depth while the other properties are used for grazing. The detailed design and flood modelling will review the Wallis/Surveyors Creek motorway and local road bridges and cross-drainage with view to reducing this impact.

RTA & Mr M L & Mrs. B M Smith

See BW17 U/S Comment See BW17 U/S Comment

BW18 0.01 -0.03Mrs. M M Percival, Mr C R & Mrs. L Parker, Mr J R & Mrs. M E & Ms. T M Hooley

Grazing Low Low High Same as BW19RTA & Mr M L & Mrs. B M Smith

Same as BW19 Same as BW19

C1074 1.00 RTA Grazing Low Low NoneFlood relief culvert and potential linkage between farm dams. No mitigation required from cross drainage

Mrs. C D ShearmanDischarges into farm dam - no issues predicted from cross drainage catchment.


BW20 0.70 MRS D L & Mr W J Wade Grazing Low Low Low

Increase in upstream flood extents is minimal but beyond the RTA ownership boundary, innundating an area containing several farm ponds. and impact is negligible. No mitigation required from cross drainage.

Mrs. C D Shearman None No mitigation required from cross drainage

C1132SR 7.62 4.10 0 (regional), 1.3 (local)Mrs. C D Shearman Grazing Low Medium Low

The provision of the Shearmans access track across Avery's Creek will result in increased local event flooding behind the road embankment. This access will be utilised for lower flood events while a controlled gated access direct to the motorway will be utilised for larger flood events that cut the access track off. Works are being undertaken in consultation with the landowner and no further mitigation is required from cross drainage.

Mrs. C D Shearman & Mr. Ljg Elliott

Discharges into wet pond area - no issues predicted from cross drainage catchment.


BW23 8.98 4.40 -1.20 Mrs Dc Ferguson Grazing Low Low None None MRS D L & Mr W J Wade See BW20 U/S comment See BW20 comment

C1150SR 19.40 0.78 0.64 RTA Grazing Low Low None None RTA None No

C1163 13.53 1.44 1.35 MR J L & Mrs K A Pyne Grazing Low Low None None RTA None No

C1206 17.76 1.49 0.91 State of NSW Woodland Low Low LowHW located over RTA project boundary within semi cleared land that is state owned. Impact is minimal and no mitigation required from cross drainage

Mr G J & Mrs. P J Field, Mr J L & Mrs. K A Payne

None No mitigation required from cross drainage

C1220 22.67 1.58 1.38 State of NSW Woodland Low Low None No mitigation required from cross drainage State of NSW None No mitigation required from cross drainage

C1290 26.61 1.01 0.86 State of NSW Woodland Low Low None No mitigation required from cross drainage State of NSWCulvert creates concentrated flow at downstream end

Flow spreader on outlet to return outlet to sheet flow

NotesAfflux assessment has been based on 100 yr ARI Storm Event on all culverts crossing the Hunter Expressway. Culvert C0436SR crossing Daracon Access Road has been assessed based on a 20yr ARI event. Culverts C1013SRa and C1013SRb have been assessed based on a 10 yr ARI event

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