28. appendix o - water quality assessment (1 of 4)

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PACIFIC NATIONAL PTY LTD

Greta Train Servicing Facility

Surface Water Management Assessment

301020-02473

10-Mar-10

Infrastructure & Environment8-14 Telford StreetNewcastle East NSW 2300 AustraliaTel: +61 2 4907 5300Fax: +61 2 4907 5333www.worleyparsons.comWorleyParsons Services Pty LtdABN 61 001 279 812

© Copyright 2010 WorleyParsons Services Pty Ltd




GRETA TRAIN SERVICING FACILITY

SURFACE WATER MANAGEMENT ASSESSMENT

PROJECT 301020-02473 - GRETA TRAIN SERVICING FACILITY

REV DESCRIPTION ORIG REVIEW WORLEY-PARSONSAPPROVAL

DATE CLIENTAPPROVAL

DATE

A Draft for Client Review

ChrisKuczera

BenPatterson

N/A

B Final for Submission

ChrisKuczera

BenPatterson

10 march2010

o:\301020\02473 greta tsf wq assessment (ck)\05_deliverables\final for submission\rp301020-02473 greta tsf wqassessment_rev b.doc

Page ii

This report has been prepared on behalf of and for the exclusive use of Pacific National Pty Ltd,

and is subject to and issued in accordance with the agreement between Pacific National Pty Ltd

and WorleyParsons Services Pty Ltd. WorleyParsons Services Pty Ltd accepts no liability or

responsibility whatsoever for it in respect of any use of or reliance upon this report by any third

party.

Copying this report without the permission of Pacific National Pty Ltd and WorleyParsons

Services Pty Ltd is not permitted.






o:\301020\02473 greta tsf wq assessment (ck)\05_deliverables\final for submission\rp301020-02473 greta tsf wq assessment_rev b.doc

Page iii 301020-02473 : Rev B : 10-Mar-10

CONTENTS

1. INTRODUCTION ................................................................................................................1 1.1 Study Objectives.................................................................................................................1 1.2 Site Locality.........................................................................................................................1 1.3 Development Proposal .......................................................................................................2 1.4 Available Data.....................................................................................................................3

2. STATUTORY REQUIRMENTS ..........................................................................................4 2.1 Director Generals Requirements ........................................................................................4 2.2 Applicable Guidelines .........................................................................................................4

3. EXISTING CONDITIONS ...................................................................................................6 3.1 Site Description...................................................................................................................6 3.2 Receiving Waters................................................................................................................6 3.3 Climatic Conditions .............................................................................................................7 3.4 Local Water Quality.............................................................................................................8

4. SURFACE WATER MANAGEMENT...............................................................................10 4.1 Potential Impacts ..............................................................................................................10 4.2 Surface Water Management Objectives...........................................................................11 4.3 Surface Water Management Plan.....................................................................................11

4.3.1 Preventative Measures ........................................................................................11 4.3.2 Rainwater Harvesting...........................................................................................12 4.3.3 Treatment of Surface Runoff................................................................................13 4.3.4 Surface Water Management during Construction................................................13

5. RAINWATER HARVESTING ...........................................................................................14 5.1 Water Balance Model .......................................................................................................14 5.2 Design Measures..............................................................................................................17

6. SURFACE RUNOFF TREATMENT .................................................................................19 6.1 WQCP Design Concept ....................................................................................................19







Page iv 301020-02473 : Rev B : 10-Mar-10

6.2 Water Quality Modelling....................................................................................................20 6.2.1 Modelling Objectives............................................................................................20 6.2.2 MUSIC Water Quality Model................................................................................21 6.2.3 Model Parameters................................................................................................21

6.3 Model Results ...................................................................................................................23 7. TRADE WASTE MANAGEMENT ....................................................................................25

7.1 Sources of Trade Waste ...................................................................................................25 7.2 Trade Waste Quality .........................................................................................................25

7.2.1 Preventative Measures ........................................................................................26 7.2.2 Treatment Measures............................................................................................26

7.3 Trade Waste Agreement...................................................................................................27 7.4 Wastewater Disposal ........................................................................................................27

8. TREATMENT OF RIPARIAN CORRIDORS ....................................................................28 8.1 Riparian Corridor Setbacks...............................................................................................28 8.2 Farm Dams .......................................................................................................................29

9. MONITORING AND RESPONSE PLAN..........................................................................30 9.1 Surface Water Monitoring Plan.........................................................................................30 9.2 Spill Response Measures .................................................................................................32 9.3 Contingency Measures .....................................................................................................33

10. POTENTIAL IMPACTS ....................................................................................................34 10.1 Water Quality Impacts ..................................................................................................34 10.2 Water Quantity Impacts................................................................................................34

11. CONCLUSION..................................................................................................................36 12. REFERENCES .................................................................................................................39







Page v 301020-02473 : Rev B : 10-Mar-10

LIST OF FIGURES

Figure 1 – Site Survey

Figure 2 – Surface Water Management Plan

Figure 3 – Water Quality Control Pond Concept







Page 1 301020-02473 : Rev B : 10-Mar-10

1. INTRODUCTION

Pacific National Pty Ltd (PN ) proposes to establish a Train Servicing Facility (TSF) on a site that is

located in the Hunter Valley, near the Township of Greta. The TSF is to provide essential operational

services for PN’s Hunter Valley rail coal haulage business. Proposed services include locomotive

provisioning, locomotive and wagon maintenance, crew changes and administration.

WorleyParsons have been engaged by PN to develop a surface water management assessment for

the development proposal. This strategy, which is documented in this report, forms part of the

Environmental Assessment for the development proposal.

1.1 Study Objectives

The following objectives have been adopted for this investigation:

Assessment of existing site water quality and hydrological conditions.

Identification of potential impacts the development proposal may have on the water qualityand environmental functionality of the receiving waters.

Development of mitigation measures to minimise any identified impacts.

Development of measures to manage and dispose of trade waste generated on-site.

Development of a surface water quality monitoring and response plan for the project.

1.2 Site Locality

The site comprises 49.3 ha of land that is located in the Hunter Valley to the west of the Township of

Greta. The site is legally described as Lot 1 DP 1129191 and is located within the Cessnock Local

Government Area (LGA). The site is bound by the Great Northern Railway to the north and east,

existing residential allotments to the south and the proposed Hunter Expressway corridor to the west.

Plate 1-1 locates the site.







Page 2 301020-02473 : Rev B : 10-Mar-10

Plate 1-1 – Site Locality

1.3 Development Proposal

Pacific National proposes to operate the Greta Train Servicing Facility to provide the following key

operational services for their Hunter Valley rail coal haulage business:

Train provisioning;

Locomotive, wagon and vehicle maintenance;

Crew changes; and

Administration.

The proposed TSF is located in the northern portion of the development site and will comprise the

following key elements:

Construction of six rail sidings to accommodate the proposed operations. Substantial

earthworks will be required to achieve the required site grades.

Construction of a range of facilities including a Provisioning Shed, Locomotive Wash and

Maintenance Facilities, a Wagon Maintenance Facility, a Wheel Lathe facility, a Vehicle

Maintenance Facility, a Fuel Storage Area and an Administration Building.







Page 3 301020-02473 : Rev B : 10-Mar-10

Construction of an access road to provide site access from Nelson Street.

Construction of the associated drainage and service infrastructure required to support the

development proposal.

Figure 2 details the development proposal.

1.4 Available Data

The following data was used for this study:

A site survey of the development site provided by PN.

Development masterplans provided by PN.

Aerial photograph of the site sourced from Google EarthTM

.

1 to 25,000 scale topographical map of the site and surrounding area.

Rainfall data and climatic statistics supplied by the Bureau of Meteorology.

Black Creek stream gauge data provided by The Department of Water and Energy .







Page 4 301020-02473 : Rev B : 10-Mar-10

2. STATUTORY REQUIREMENTS

2.1 Director Generals Requirements

In accordance with Section 75F of the EP&A Act, the Director General of the Department of Planning

has issued requirements for the preparation of the Environmental Assessment for the proposed Greta

TSF project. The requirements that have been addressed in this report are detailed in Table 2-1.

Table 2-1 – Director General’s requirements specific to the surface water management aspects of the

project.

Director General’s RequirementApplicable Section of

Report

A description of the existing environment Section 3

An assessment of the potential impacts of both the construction and

operation stages, in accordance with relevant guidelines and policies.Sections 4 and 10

A description of measures that would be implemented to avoid,

minimize, manage, mitigate, offset and/or monitor the impacts of the

project.

Sections 5, 6, 7, 8 and 9

2.2 Applicable Guidelines

G UIDELINES

There are no known guidelines that specifically address water management issues for rail yards.

However, the following guidelines are considered to be applicable to various aspects of this

development proposal.

Australian Rainfall and Runoff

Australian Rainfall and Runoff (AR&R ) is a document published in 1987 by the Institution of

Engineers, Australia (IEAust). This document has been prepared to provide designers with the best

available information on design flood estimation and is widely accepted as a design guideline for all

flood and stormwater related design in Australia.







Page 5 301020-02473 : Rev B : 10-Mar-10

Erosion and Sediment Control Guidelines

Managing Urban Stormwater: Soils and Construction (Blue Book) is guideline that documents best

practice erosion and sediment control measures. The guideline was published by the Department of

Housing in 1998.

Australian Runoff Quality

Australian Runoff Quality (ARQ) is a document published in 2006 by IEAust which provides design

guidelines for all aspect of water sensitive urban design (WSUD ), including preventative measures,

source controls, conveyance controls and end of line controls. Additionally, it provides guidance for

water quality modelling as well as stormwater harvesting and re-use.

Constructed Wetland Manual

The Constructed Wetlands Manual is a document published by the Department of Land and Water

Conservation (DLWC ) in 1998. The manual provides comprehensive technical information regarding

planning, design, construction and operation of constructed wetlands for a range of applications.

Guidelines for Controlled Activities

The NSW Office of Water (DECCW ) has developed guidelines to assist applicants who are

considering carrying out a controlled activity on waterfront land. The guidelines provide information

on the recommended treatment of riparian corridors and design measures for any in-stream

structures such as culverts or crossings.

Water Harvesting Guidelines

Managing Urban Stormwater: Harvesting and Reuse provides guidance on the planning, design and

operation of a range of stormwater harvesting and re-use applications. The document was published

by the Department of Environment and Conservation in 2006.

Australian Guidelines for Water Quality Monitoring and Reporting – ANZECC, 2000

These guidelines are the benchmark document of the National Water Quality Management Strategy

(NWQMS) which is used for comparison of water quality monitoring data throughout Australia.







Page 6 301020-02473 : Rev B : 10-Mar-10

3. EXISTING CONDITIONS

3.1 Site Description

The site comprises 49.6 ha of land that is located to the west of the Township of Greta. The site

fronts approximately 2.4km of the Main Northern Railway corridor, which forms the eastern and

northern site boundary. The site topography is characterised by undulating hills and drainage lines

with grades ranging from 3 to 10%. The steeper topography is located in the western portion of the

site. Figure 1 presents a site survey.

The south-eastern portion of the site comprises cleared grazing land, while the northern and western

portions of the site are vegetated with native vegetation. A number of small farm dams exist

throughout the site. The extent of vegetation and farm dam locations is evident in Figure 1, which

includes an aerial photograph of the site.

There are four ephemeral watercourses that traverse the site. The largest watercourse is Sawyers

Creek, which traverses through the southern portion of the site. Sawyers Creek has a contributingcatchment area of approximately 5km

2that extends approximately six kilometres to the south of the

site, to the Molly Morgan Mountain Range. Sawyers Creek is classified as a second order

watercourse using the Strahler System of ordering watercourses. Two unnamed smaller first order

watercourses and one unnamed second order watercourse traverse the site to the north of Sawyers

Creek. For the purposes of this report, these unnamed watercourses have been numbered 1 to 3 in a

north to south sequence. Refer to Figure 1 for watercourse alignments.

The site is undermined by the workings of the remnant Anvil Creek Colliery, which operated between

1884 and 1912. Geotechnical investigations undertaken by Douglas Partners have identified the

potential for pot hole subsidence to occur in the southern portion of the site, where the underground

workings are less than 40 m below the surface.

3.2 Receiving Waters

All four on-site watercourses are tributaries to Anvil Creek, which has a catchment area of 3,653ha.

The Anvil Creek Catchment is characterised by undulating and flat terrain with slopes ranging from 0

to 10%. Rural land-uses dominate the catchment, with pasture/grazing/cropping making up 48% of

the total area. In addition, there are small areas of intensive agriculture. Approximately 40% of the

catchment is currently forested and 12% is occupied by urban settlement. There are numerous

remnant mining operations located through the catchment (Cessnock City Wide Settlement Strategy,

2003 ). The Cessnock City Wide Settlement Strategy describes Anvil creek has relatively degradedwhen compared to other, less developed, catchments in the Cessnock City Council LGA.







Page 7 301020-02473 : Rev B : 10-Mar-10

Anvil Creek joins Black Creek downstream of the Township of Branxton. Black Creek is a major

tributary of the Hunter River.

3.3 Climatic Conditions

R AINFALL D ATA

Daily rainfall and climatic data is available from Bureau of Meteorology (BoM ) Weather Station 61025

(Greta Post Office ) that was located within 500m of the project area. BoM Station 061025 operated

between 1902 and 1978 providing a comprehensive data set of climatic conditions for the Greta area.

Key statistical rainfall data from BoM Station 61025 is summarised in Table 3-1.

Table 3-1 – Local Rainfall Data

BoM Station 61025

(Greta Post Office)

Annual Rainfall Depth

(mm/year)

Mean 766

10th

Percentile 514

50th

Percentile 761

90th

Percentile 1000

E VAPORATION D ATA

Average monthly evaporation (ET ) and areal potential evapotranspiration (PET ) rates at Greta were

extracted from the monthly climate maps provided by the BoM. The adopted monthly average

evaporation and PET depths are presented in Table 3-2.







Page 8 301020-02473 : Rev B : 10-Mar-10

Table 3-2 – Average evaporation and potential evapotranspiration at the Greta

Month

Average Monthly

Evaporationˆ

(mm/month)

Areal Potential

Evapotranspiration

(mm/month)

January 180 170

February 175 140

March 125 130

April 100 90

May 90 65

June 80 60

July 75 50

August 90 70

September 120 90

October 140 120

November 180 150

December 200 165

^ Evaporation from a Class A evaporation pan.

3.4 Local Water Quality

A desk top search was undertaken to collate publicly available water quality data from both Anvil and

Black Creeks. Water quality information was sourced from the following sources:

The Department of Water and Energy operates a gauging station that is located immediately

downstream of the confluence of Black and Anvil Creeks (Station Number 210131). Salinity

measurements were recorded daily between 1993 and 2002.

In stream Total Phosphorous and Nitrogen measurements collected by Hunter Water

upstream and downstream of the Branxton Wastewater Treatment Plant were published in

the publically available water quality assessment titled Branxton Wastewater Treatment

Works Upgrade: Load-Based Water Quality Assessment (Cardno, February, 2009).

Table 3-3 compares the above water quality data to the default trigger values documented in the

ANZECC guideline for fresh and marine water quality.







Page 9 301020-02473 : Rev B : 10-Mar-10

Table 3-3 – Comparison of known water quality data to ANZECC trigger values

AnalyteTypical Observed Values in

Black and Anvil Creeks

ANZECC Default Trigger values for

lowland rivers

Salinity Average: 1554 µs/cm

10th

Percentile: 909 µs/cm

90th

Percentile: 2162 µs/cm

Trigger values range from 125 to

2200 µs/cm. NSW coastal Rivers are

typically in the 200-300 µs/cm range.

Total Nitrogen Observed concentrations^ range

from 0.5mg/l to >3mg/l. The

average concentration is

approximately 1.5mg/L^^

0.35 mg/L

Total Phosphorus Observed concentrations^ range

from 0 mg/l to >0.3mg/l. The

average concentration is

approximately 0.05mg/L^^

0.025 mg/L

^ Refers to observations recorded upstream of the Branxton WWTP.

^^ Water quality data was only available in graphical form. The estimated average concentrations were estimated from thegraphs and should therefore be considered as indicative rather than absolute.

The water quality observations presented in Table 3-3 indicate that the local water quality in Black

and Anvil Creeks significantly exceeds the ANZECC default trigger values for salinity. In addition, the

observed salinity levels are significantly higher than the median value of 670 µs/cm reported in the

Hunter River at Greta (Department of Land and Water Conservation, 2003 ). Both observed Total

Nitrogen and Total Phosphorus water quality trends were also substantially higher than the ANZECC

default trigger values.

The available data indicates that the water quality in both Anvil and Black Creeks is degraded. This

hypothesis is supported by the Cessnock City Council’s City Wide Settlement Strategy whichdescribes the water quality in both Anvil and Black Creek Catchments as being ‘very highly saline’

and degraded (Cessnock City Council, 2003 ).







Page 10 301020-02473 : Rev B : 10-Mar-10

4. SURFACE WATER MANAGEMENT

This section discusses the potential surface water impacts and proposed management measures.

4.1 Potential Impacts

The following contamination processes and pathways have been identified as potentially occurring

during the construction and operational phases of the development proposal:

Construction Phase: The construction of the TSF is to involve significant earthworks to

achieve the proposed site grading. As a result of the soil disturbances, there is potential for

temporary increases in sediment loads to occur in runoff from the site. Accordingly, erosion

and sediment control measures will be required to minimise the occurrence of sediment

being exported from the site.

Operation Phase: During operational stage of the TSF, the following potential contaminant

sources have been identified:

− Locomotive Wash Facility: Locomotives will be washed in a designated facility.

Runoff from this washing process is likely to comprise poor water quality, with

elevated concentrations of oil and grease, heavy metals, nutrients and Chemical

Oxygen Demand (COD ). Accordingly, all wash down water will be treated on-site to a

suitable quality required for disposal under a trade waste agreement.

− Work Shops and Provisioning Shed: Internal runoff from the onsite workshops and

the provisioning shed is likely to contain similar water quality to runoff from the

locomotive wash facility. As such, all internal runoff will be treated on-site to a suitable

quality required for disposal under a trade waste agreement.

− Rail Yard and Maintenance Areas: It is likely that the rail sidings would generate a

low to moderate particulate load (comprising coal and non coal particulates ). Coal

particulates can contain soluble salts and acid forming materials. However, as no

handling of coal will be undertaken on-site, the coal particulate load is expected to be

low (primarily through coal failing from wagons ) and no significant acid or salinity

issues are expected. In addition to particulate loads, there is potential for low to

moderate levels of hydrocarbon and heavy metal contamination resulting from

machinery operations. All surface runoff from the rail yard would be treated in Water

Quality Control Ponds (WQCPs ) designed to remove suspended sediments and low

to moderate levels of heavy metals and oil and grease prior to discharge. The oil and

grease loads are expected to be higher in runoff from the key infrastructure and

maintenance area (defined as the area between the Administration Building and the







Page 11 301020-02473 : Rev B : 10-Mar-10

fuel storage area ). As such, a Gross Pollutant Trap (GPT) with hydrocarbon removal

capabilities will pre-treat runoff from this area prior to treatment in the WQCPs.

− Accidental Spills: The rail yard operations will involve the handling of large volumes

of liquids such as fuel, oil, radiator fluid and hydraulic fluid. As with any industrial

operation, there is potential for an accidental spill or leakage to occur. In addition,

spills may occur from machinery failure. While management measures will be

implemented to reduce the probability of an accidental spill occurring, contingency

measures will also be implemented to enable any spill to be contained on-site and be

effectively remediated.

4.2 Surface Water Management Objectives

The following surface water management objectives have been established:

Implement best practise surface water management measures.

Separate clean and dirty water streams to increase the effectiveness of treatment

measures.

Provide treatment for all surface runoff from the development area.

Establish a trade waste collection and treatment facility to treat all water generated from

locomotive washing and internal runoff from work shops and provisioning sheds.

Implement stormwater harvesting where practical.

Establish contingency measures that enable any accidental spill to be contained on-site and

be effectively remediated.

4.3 Surface Water Management Plan

A Surface Water Management Plan (SWMP ) has been developed based on the surface water

management objectives discussed in Section 4.2. The SWMP incorporates a range of preventative,

treatment and contingency measures, which are discussed in the following sections. The following

sections should be read in conjunction with Figure 2, which graphically illustrates the SWMP.

4.3.1 Preventative Measures

Preventative measures are the most effective stormwater management methods as they control the

source of any surface water management issue. The following preventative measures are proposed:







Page 12 301020-02473 : Rev B : 10-Mar-10

Isolation of the Clean Water Drainage – As detailed in Figure 2, the natural site

topography grades from the west to the east. It is proposed to construct a clean water

collection system that diverts all arriving flow from up gradient areas into a series of culverts

that pass under the TSF. As indicated in Figure 2, all surface runoff from the TSF will be

treated prior to release into the clean water system.

Isolation of Highly Polluting Areas – All workshops and locomotive washing and

provisioning facilities will be enclosed and covered. As such, any internal surfaces that may

contain pollutants will not be exposed to rainfall and will not contribute to the surface runofffrom the site. All internal runoff will be collected and treated in a separate system and

managed under the trade waste management scheme that is discussed in Section 5.

Operational Procedures – PN will develop operational procedures to ensure that all on-site

activities are undertaken in accordance with best practice environmental management

standards. Operational procedures would be required for the following tasks:

− Transfer and storage of liquids such as fuel and oils.

− Management of liquid and solid waste streams.

As part of the operational procedures, PN will provide training to relevant personal as

required.

Stabilisation of Exposed Soils – Any exposed soils in non-trafficable areas should be

stabilised with vegetation and mulch to prevent soil loss. This is particularly important on

steep slopes such as batters.

4.3.2 Rainwater Harvesting

A rainwater harvesting scheme is proposed to supplement the on-site non-potable water

requirements for both toilet flushing and locomotive washing. The scheme will incorporate the

following features:

Rainwater will be harvested from the roofs of all on-site buildings.

Harvested rainwater from the Administration building, Wheel Lathe facility and the

Provisioning Shed will be re-used for toilet flushing in each respective building. Rainwater

tanks sizes for each building are detailed in Figure 2.

Harvested rainwater from the Locomotive, Road Vehicle and Wagon Maintenance Sheds

and the Locomotive Wash Facility will be reused for toilet flushing in each building as well as

to supplement the water requirements for the Locomotive Wash Facility.

The proposed rainwater harvesting scheme is discussed in detail in Section 5.







Page 13 301020-02473 : Rev B : 10-Mar-10

4.3.3 Treatment of Surface Runoff

As indicated in Figure 2, all surface runoff from the TSF will be treated in Water Quality Control

Ponds (WQCPs ) prior to discharge. WQCPs were selected as the preferred water quality treatment

method as they are suited to flat sites and facilitate relative ease of maintenance. WQCPs are

effective in removing sediment, nutrients and other pollutants such as oils and greases and heavy

metals from runoff through a range of physical, biological and chemical processes. The proposed

WQCP design measures are discussed in detail in Section 6.

As discussed in Section 4.1, there is potential for increased oil and grease concentrations in runoff

from the infrastructure and maintenance area, which is designated in Figure 2. All runoff from this

area will be pre-treated in a GPT with oil and grease removal capabilities (typical proprietary units

include HumeCeptor or SpelCeptor ) prior to treatment in the WQCPs.

4.3.4 Surface Water Management during Construction

During construction, sediment and erosion control measures would be designed and installed in

accordance with the NSW Department of Housing “Managing Urban Stormwater – Soils and

Construction ” (Blue Book ). A detailed soil and water management plan will be prepared at the

detailed design stage of each construction stage. The soil and water management plan will include

the following information:

Areas of disturbance during each stage of construction.

Clean and dirty water management.

The location and size of sediment basins.

The location and specifications of erosion control measures such as silt fences.

The treatment of areas that require temporary stabilisation, such as stockpiles.

.







Page 14 301020-02473 : Rev B : 10-Mar-10

5. RAINWATER HARVESTING

As discussed in Section 4.3.2, a review of possible rainwater harvesting schemes was undertaken

and the following four rainwater harvesting schemes are proposed:

Scheme A – Harvests runoff from the Administration building for internal re-use for toilet

flushing.

Scheme B – Harvests runoff from the Wheel Lathe facility for internal re-use for toilet

flushing.

Scheme C – Harvests runoff from the Provisioning Shed for internal re-use for toilet

flushing.

Scheme D – Harvests runoff from the Locomotive Maintenance Shed, Road Vehicle Centre,

Wagon Maintenance Shed and the Locomotive Wash Facility. Harvested water will be re-

used for toilet flushing in each building as well as supplement the water requirements for the

Locomotive Wash Facility.

This section details water balance modelling undertaken to size each of the above schemes and

discusses the design concepts.

5.1 Water Balance Model

The efficiency of a rainwater harvesting system is dependant on the catchment area and

characteristics, rainfall characteristics (rainfall depths and variability ), the storage capacity of the

tanks and the demand usage and variability. Water balance modelling was undertaken to examine

the above factors. The objective of modelling was to determine appropriate design parameters for the

harvesting schemes.

C ATCHMENT AREAS

Roof areas contributing to each of the proposed harvesting schemes were determined from the

preliminary design plans provided by PN. Table 5-1 details the estimated roof areas for each scheme.







Page 15 301020-02473 : Rev B : 10-Mar-10

Table 5-1 – Estimated Catchment Areas

Harvesting Scheme Available Roof Area (m2)

Scheme A 570

Scheme B 760

Scheme C 2,150

Scheme D 3,130

Total 6,610

An initial loss run-off model was used to determine the harvesting volume. A 5mm per day initial loss

was adopted to account for losses associated with a first flush by-pass system.

D EMAND ANALYSIS

It is proposed to re-use harvested rainwater for toilet flushing and locomotive washing. These

demands are anticipated to be constant, with no seasonal variation. As such, estimated average

daily demands were adopted for water balance calculations. The estimated daily water demands for

each scheme are summarised in Table 5-2.

Table 5-2 – Average Daily Water Demands

Harvesting

Scheme

Toilet Flushing

(KL/day)^

Locomotive Washing

(KL/day)

Total

(KL/day)

Scheme A 0.32 - 0.32

Scheme B 0.05 - 0.05

Scheme C 0.76 - 0.76

Scheme D 0.32 3.00^^ 3.32

Total 1.46 3.00 4.46

^ Toilet flushing demands are based on the predicted staffing levels provided by PN for Stage 3 of the operation. Toilet flushing

volumes were calculated based on 1 full flush (9l) and 4 half flushes (4.5l) per 8hr shift.

^^ Refer to Section 7 for further information regarding the locomotive wash water usage.

S TORAGE V OLUMES

The water balance model was used to assess the efficiency of a range of rainwater tank storage

sizes. The harvesting efficiency (volume of harvested water / total demand ) for each scheme was

assessed by running a continuous water balance simulation using 76 years of local daily rainfall data

(sourced from BoM Station 61025 ). The use of a long continuous simulation period allows for the

effects of both short and long term rainfall variations to be captured in the model results.







Page 16 301020-02473 : Rev B : 10-Mar-10

Rainwater tanks for Schemes A, B and C were sized to achieve a minimum 80% harvesting

efficiency. A 50% harvesting efficiency was selected for Scheme D, which has a smaller demand to

catchment area ratio. Water balance results are presented in Table 5-3.

Table 5-3 – Water Balance Results

Harvesting

Scheme

Tank Size

(KL)

Average

Harvested

Volume

(KL/year)

Harvesting

Efficiency

(% of Total

Demand)

Scheme A 20 100 85%

Scheme B 5 18 97%

Scheme C 30 225 81%

Scheme D 60 615 51%

Total 115 958 59%

As detailed in Table 5-3, water balance modelling indicates that the proposed stormwater harvesting

schemes would facilitate an average 958KL/year reduction in mains water usage, which accounts for

59% of the estimated demand. The most significant contribution arises from Scheme D. Plate 5-1

presents the key model results on a monthly basis, demonstrating that the scheme is more efficient

during higher rainfall months.

Average Rainwater Harvesting Effectivness - Scheme D

0.0

50.0

100.0

150.0

200.0

250.0

1 2 3 4 5 6 7 8 9 10 11 12

Month

V o l u m e o f w a t e r ( k

l )

0

20

40

60

80

100

120

R a i n f a l l D e p t h ( m m

)

Average Rainfall Avg Runoff Avg Demand Avg Mains Supply Avg Harvested

Plate 5-1 Scheme D – Monthly Water Balance Results







Page 17 301020-02473 : Rev B : 10-Mar-10

5.2 Design Measures

W ATER C OLLECTION AND S TORAGE

As rainwater will be harvested from the roofs of all buildings, a guttering system will be required to

collect all roof water and direct it into the rainwater tanks. In order to maintain an acceptable water

quality, it is recommended that the following measures are implemented in the gutter design:

Ideally, there should be no trees overhanging the harvesting roof area. If vegetation does

overhang the roof area then a leaf guard guttering system will be required to prevent organic

matter entering the rainwater tanks.

A first flush by-pass system will be required to discard the initial runoff from the roof, which

generally comprises poorer water quality.

W ATER Q UALITY T REATMENT

The NSW Government Guideline titled Managing Urban Stormwater – Harvesting and Reuse (DECC,

2006 ) provides stormwater quality criteria for managing health risks associated with stormwater

harvesting schemes. As discussed above, harvested water would be used for toilet flushing and

locomotive washing. Locomotive washing will comprise spraying water through a high pressure

nozzle. This process would create airborne droplets that would directly expose employees operating

the wash facility to any waterborne pathogen. As such, the locomotive washing process is

considered primary contact and the following water quality criteria are required:

E. Coli < 1 cfu/100 ml.

Turbidity < 2 NTU.

pH 6.5 – 8.5.

1 mg/L Cl2 residual after 30 minutes or equivalent level of pathogen reduction.

The above water quality criteria could be achieved using a pressurised filtration unit followed by

chlorine dosing. A water quality monitoring plan would be developed to monitor the effectiveness of

this treatment.

Re-use of harvested stormwater for toilet flushing is considered to be secondary contact and no

treatment is required other than a first-flush diversion.







Page 18 301020-02473 : Rev B : 10-Mar-10

M AINTENANCE R EQUIREMENTS

The proposed stormwater harvesting scheme will require the following ongoing maintenance tasks:

Removal of any accumulated debris from the gutter system.

Maintain all pumps and tanks in good working order.

Maintain the treatment system in accordance with manufacturer’s recommendations. This

may include a requirement to back flush water through the filter.

Storage and treatment of chemicals will need to be managed in accordance with relevant

Australian Standards.







Page 19 301020-02473 : Rev B : 10-Mar-10

6. SURFACE RUNOFF TREATMENT

As discussed in Section 4, all surface runoff from the development area will be treated in one of five

Water Quality Control Ponds (WQCPs ). WQCPs were selected as the preferred water quality

treatment method as they are suited to flat sites and facilitate relative ease of maintenance. WQCPs

are effective in removing suspended sediment and other pollutants such as oils and greases and

heavy metals from runoff through a range of physical, biological and chemical processes. Water

quality modelling was undertaken to determine the key design parameters for each of the five WQCP.

This section discusses the modelling assumptions, methodologies and results and presents a design

concept for the WQCPs.

6.1 WQCP Design Concept

The design objectives of the WQCPs are to provide water quality treatment to remove suspended

sediments and low to medium levels of heavy metals and oils and greases as well as facilitate relative

ease of maintenance. As such the WQCPs are proposed to incorporate a two stage treatment

process incorporating the following design measures (Figure 3 details the design concept ):

Inlet Pond:- is the initial treatment zone, which is designed to trap coarse to medium size

sediments and debris. As the majority of incoming sediment will be removed in this zone,

vehicle maintenance will be provided to facilitate the removal of trapped sediment and

debris. A weir will control the overflow from the inlet pond into the wetland zone.

Macrophyte Zone:- provides secondary treatment targeting the removal of finer sediments,

heavy metals and oils and greases. The wetland zone comprises the following three

components:

− Deep Water Zones – serves as an oxidation and photosynthesis zone, enabling

oxidation of organics and metals as well as ultra violet breakdown of oils and greases

and organic compounds. Deep water zones also provide permanent pools that increase

the retention volume of the WQCP and provide important refuge for wetland biota during

dry periods. Deep water zones should not exceed a depth of 2.0m to avoid stratification.

− Macrophyte Benches – are shallow benches constructed 200 to 400mm below the

permanent water level. These benches would be vegetated with macrophyte species

that provide effective removal of finer particulates and soluble pollutants such as soluble

metals and nutrients.

− Extended Detention – refers to a temporary detention volume that is located above the

permanent water level. Extended detention moderates the outflows from the WQCP and

allows for a greater volume of runoff to be treated.







Page 20 301020-02473 : Rev B : 10-Mar-10

Outlet Control – It is proposed to construct a grated inlet pit to control outflow from the

WQCP. The outflow structure will have a small orifice control set at the permanent water

level and a higher capacity weir control set at the extended detention level. All overflows

would be conveyed into the downstream receiving water through piped drainage.

M AINTENANCE R EQUIREMENTS

The proposed WQCPs will require the following ongoing maintenance tasks:

Removal of accumulated sediment and debris from the inlet pond. As indicated in Figure 3,

an access road will be provided to facilitate access for a small front-end-loader or bobcat.

The inlet pond should be cleaned on an annual basis or if accumulated sediment exceeds

30% of the pond volume.

Over an extended period of time, accumulated sediment in the macrophyte zone may

require removal. The frequency of this can be minimised by effective maintenance of the

inlet pond.

A detailed maintenance plan shall be prepared as part of the detailed design of the WQCPs.

6.2 Water Quality Modelling

Water quality modelling was undertaken to determine the key design parameters for each WQCP.

This section discusses the modelling methodologies, assumptions and results.

6.2.1 Modelling Objectives

There are no known water quality guidelines for rail yard facilities. As discussed in Section 4.1,

surface runoff from the TSF is expected to generate moderate levels of suspended sediments with

the potential for minor to moderate levels of heavy metals and oils and greases to also occur. Thekey adopted design objective for the WQCPs is to achieve an 80% reduction in Total Suspended

Sediment (TSS) concentrations. This is consistent with the water quality guidelines Australian Runoff

Quality (IEAust, 2006 ) which has been developed as urban stormwater management guidelines.

It is noted that the removal of heavy metals is correlated with removal of finer colloidal particulates

and biological process associated with wetlands. (Constructed Wetlands Manual, DLWC, 1998 ). It

has therefore been assumed that a WQCP sized to remove 80% of suspended sediments will also

provide sufficient hydraulic residence time to facilitate the removal of heavy metals (which are

typically bound to particulates ) and low to moderate levels of oil and greases which are

biodegradable and will break down over time when exposed to biological and photosynthetic process

(Australian Runoff Quality, 2006 ). It is noted that a GPT, with oil and grease removal capabilities will







Page 21 301020-02473 : Rev B : 10-Mar-10

pre-treat runoff from the key infrastructure and maintenance area (area defined in Figure 2 ), which is

considered to have the potential for elevated oil and grease concentrations in the surface runoff.

6.2.2 MUSIC Water Quality Model

MUSIC is a conceptual water quality assessment model developed by the Cooperative Research

Centre for Catchment Hydrology (CRCCH ). MUSIC can be used to estimate the long-term annual

average runoff volume generated by a catchment as well as the expected pollutant loads. MUSIC is

able to conceptually simulate the performance of a series of stormwater treatment measures(treatment train ) to assess whether a proposed water quality strategy is able to meet specified water

quality objectives.

To undertake this water quality assessment, a MUSIC model was established for each of the five

catchments within the subject site. The model was used to estimate the pollutant load generated

from the development and estimate the indicative size of the WQCPs required to meet the water

quality targets defined above.

6.2.3 Model Parameters

This section details to adopted model parameters,

R AINFALL

In order to develop a model that could comprehensively assess the performance of the proposed

SWMP, the use of 6 minute pluviograph data was considered necessary. 6 minute rainfall records

obtained from BoM Station 061174, located at Millfield, were used for MUSIC water quality

simulations. The rainfall records at BoM Station 061174 extend between 1959 to 1980 and were

reviewed to determine that the average annual rainfall depth is approximately 800mm, which is similar

to the long term average observed at BoM Station 61025 (766mm). Observed rainfall between 1969

and 1973 was used for all MUSIC water quality simulations. This period was selected as it represents5 consecutive years of approximate average rainfall.

E VAPORATION

Monthly areal potential evapotranspiration (PET ) rates for the site were estimated from PET data

provided by the Climate Atlas of Australia (BoM). These values have been previously reported in

Table 3-2.







Page 22 301020-02473 : Rev B : 10-Mar-10

C ATCHMENT AREAS

As detailed in Figure 2, it is proposed to divide the development area into five sub-catchments. In

order to accurately determine the expected runoff volumes and suspended sediment concentrations,

the areas of the following land-surfaces were estimated for each catchment:

Rail yard area;

Roof area;

Paved area; and

Vegetated area.

The resulting areas are presented in Table 6-1.

Table 6-1 – Catchment Areas

Catchment

Rail Yard

Area

(ha)

Roof Area

(ha)

Paved Area

(ha)

Vegetated

Area

(ha)

Total Area

(ha)

SC - 1 1.35 0.22 0.19 0.54 2.3

SC - 2 1.85 - 0.14 1.31 3.3

SC - 3 3.50 0.45 1.60 3.15 8.7

SC - 4 1.45 - 0.22 0.43 2.1

SC - 5 1.80 - 0.35 1.45 3.6

Total 9.95 0.67 2.50 6.88 20.00

C ATCHMENT P ARAMETERS

Rainfall runoff parameters were established for each of the above land-surfaces that have the

following catchment characteristics:

Paved and roof areas were assumed to be 100% impervious. A 1 mm initial loss was

applied to the rainfall runoff model.

Rail yard areas will comprise ballast placed on a compacted foundation that grades towards

a piped drainage system. It is expected that the ballast would attenuate runoff and

moderate losses would occur through evaporation of any retained runoff in the ballast.

However, as the ballast would be well drained the volumetric runoff is likely to be higher

than that from a vegetated surface.

All areas of the catchment outside of the indentified rail yard, roof and pavement areas wereassumed to comprise predominately (90%) vegetated surfaces. A 10% impervious







Page 23 301020-02473 : Rev B : 10-Mar-10

percentage adopted for modelling purposes to account for any potential additional

impervious or compacted pervious surfaces that were not identified on the concept design

drawings.

Table 6-2 presents the adopted modelling parameters and resulting average annual volumetric runoff

coefficient for each land surface. In addition, the TSS Event Mean Concentrations (EMCs ) for each of

land-surface was derived from ‘Urban Stormwater Quality: A Statistical Overview ’ (Duncan, February

1999 ) and ‘Australian Runoff Quality ’ (Engineers Australia, 2005 ). Adopted EMCs are presented in

Table 6-2.

Table 6-2 – MUSIC Parameters

MUSIC Parameters

Land-SurfacePercentage

Impervious

Average

Annual

Runoff

Coefficient

Field

Capacity /

Soil Storage

(mm)

Infiltration

coefficient

and exponent

TSS - Event

Mean

Concentration

(mg/l)

Rail yard

Areas0% 0.30

FC = 25mm

SS = 25mm

Coeff a = 500

Exp b = 1158 mg/l

Roof Areas 100% 0.88 NA NA 32 mg/l

Paved Areas 100% 0.88 NA NA 158 mg/l

Vegetated

Areas10% 0.15

FC = 120mm

SS = 80mm

Coeff a = 200

Exp b = 180 mg/l

6.3 Model Results

The MUSIC water quality model was used to determine key design parameters for each of the

proposed WQCPs. The proposed rainwater harvesting system was also included to account for the

reduced volume of runoff from roof areas. Key design parameters for each WQCP are presented in

Table 6-3. Figure 3 details the WQCP design concept.

Table 6-3 – WQCP Properties

Catchment

Catchment

Area

(ha)

Inlet Pond

Volume

(m3)

Macrophyte

Zone Area

(m2)

Macorphyte

Zone Volume

(m3)

Extended

Detention

Volume

(m3)

SC - 1 2.3 150 380 340 114

SC - 2 3.3 180 495 450 149

SC - 3 8.7 430 1305 1200 392

SC - 4 2.1 120 315 290 95

SC - 5 3.6 180 540 490 162Total 20.00 1060 3035 2770 1821







Page 24 301020-02473 : Rev B : 10-Mar-10

The WQCP design parameters detailed in Table 6-3 have been determined as the minimum

requirement to meet the water quality treatment targets outlined in Section 6.2. Accordingly, these

design parameters will be applied at the detailed design stage.

The introduction of impervious surfaces and the rail yard formation are likely to increase the

volumetric runoff from the site. Table 6-4 presents the estimated average annual runoff volumes and

associated run-off coefficients for each sub catchment under existing and developed conditions. The

volumetric runoff coefficient under existing conditions was estimated to be 0.1, which is approximately

mid-range in the values recommended in Table 10-5 of the Constructed Wetlands Manual (DLWC,1998) for a site containing elastic clay soils and mean annual rainfall ranging between 500-900mm.

Table 6-4 – Estimated Volumetric Runoff

Developed State Existing State

Catchment

Catchment

Area

(ha)

Average

Volumetric

Runoff

(ML)

Average

Volumetric

Runoff

Coefficient

Average

Volumetric

Runoff

(ML)

Average

Volumetric

Runoff

Coefficient

Increase in

Average

Annual

Runoff

Volume

(ML)

SC - 1 2.3 6.0 0.32 1.84 0.10 4.1

SC - 2 3.3 6.1 0.23 2.64 0.10 3.5

SC - 3 8.7 23.2 0.33 6.96 0.10 16.2

SC - 4 2.1 5.0 0.30 1.68 0.10 3.3

SC - 5 3.6 7.5 0.26 2.88 0.10 4.7

Total 20.00 47.8 0.30 16 0.10 31.8

The modelling results presented in Table 6-4 indicate that average annual runoff from the 20ha

development area would increase from approximately 16 ML/year to 48 ML/year. This increase in

runoff volume is unavoidable as it is attributed to the removal of vegetated surfaces which absorb the

majority of rainfall. Significant attenuation would be provided within the rail yard ballast and WCQPs

which would moderate peak flows leaving the site to sustainable rates.

The potential impact of the increased runoff volume on the receiving waters is discussed in Section

10.2.






7. TRADE WASTE MANAGEMENT

Trade waste will be generated from the locomotive wash down bay as well as the various work shops.

All trade waste will be treated on-site to remove the majority of oils and greases and disposed under a

trade waste agreement. This section discusses the proposed trade waste management measures.

7.1 Sources of Trade Waste

Trade waste would be generated from the following sources:

Runoff from the locomotive wash facility:- PN have advised that approximately 1 to 2

locomotives will be washed per day. Information provided by EDI Downer indicates that

their locomotive wash facility at Kooragang Island washes 1 locomotive per day and

generates approximately 10KL of trade waste per week. Hence, the estimated volume of

water generated by washing 2 locomotives per day would be expected to be in the order of

20 KL per week or 3 KL per day.

Workshop Runoff:- Internal runoff from the locomotive maintenance facility, road vehicle

service centre, fuel storage area, wheel lathe facility and the provisioning shed would be

collected as trade waste. The majority of runoff would be generated from washing down

workshop floors and equipment. It is expected that approximately 1 KL/day of water would

be generated from these sources.

The collective volume of trade waste generated on-site would be approximately 4KL/day.

7.2 Trade Waste Quality

Runoff from the locomotive wash bay and other trade waste sources is expected to contain elevatedlevels of oils and greases, suspended solids, heavy metals, nutrients and chemical oxygen demand.

Management and treatment measures will be required to maintain a water quality that is acceptable

for disposal as trade waste. The following sections discuss these measures.

Water quality samples were collected at a similar train servicing facility to determine indicative water

quality parameters. The samples were collected from a holding tank that stored treated water for

collection by a liquid waste contractor. The sampled water had been treated through an on-site

treatment system that comprised a gravity separation tank with an oil skimmer and a coalescing plate

oil and grease separator. Laboratory analysis of the samples indicated that the sampled water can be

treated to a suitable standard for discharge under a trade waste agreement provided that the

preventative and treatment measures detailed in the following sections are implemented.

28. appendix o - water quality assessment (1 of 4)

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