Leachate Management Plan - epa.wa.gov.auepa.wa.gov.au/sites/default/files/Referral_Documentation/14 - Leacha… · 1 Introduction Talis Consultants Pty Ltd (Talis) was commissioned

Leachate Management Plan Pilbara Regional Waste Management Facility Shire of Ashburton

TW18004 - Leachate Management Plan.1a July 2018 | Page 1

Assets | Engineering | Environment | Noise | Spatial | Waste

Leachate Management Plan

Pilbara Regional Waste Management Facility

Prepared for Shire of Ashburton

July 2018

Project Number: TW18004


TW18004 - Leachate Management Plan.1a July 2018 | Page i

DOCUMENT CONTROL

Version Description Date Author Reviewer

0a Internal Review 13/07/18 LW + CP LM

1a Finalised 25/07/18 LW + CP LM

Approval for Release

Name Position File Reference

Ronan Cullen Director and Waste Management

Section Leader TW18004 - Leachate Management Plan.1a

Signature

Copyright of this document or any part of this document remains with Talis Consultants Pty Ltd and cannot be used,

transferred or reproduced in any manner or form without prior written consent from Talis Consultants Pty Ltd.


TW18004 - Leachate Management Plan.1a July 2018 | Page ii

Table of Contents 1 Introduction ......................................................................................................................... 1

1.1 Background ............................................................................................................................. 1

1.2 Purpose ................................................................................................................................... 1

2 Site Description .................................................................................................................... 3

2.1 Topography ............................................................................................................................. 3

2.2 Groundwater ........................................................................................................................... 3

3 Local Climate Data ................................................................................................................ 4

3.1 Temperature ........................................................................................................................... 4

3.2 Rainfall .................................................................................................................................... 4

3.3 Pan Evaporation ...................................................................................................................... 5

3.4 Other Key Climate Data .......................................................................................................... 5

4 Landfill Leachate Management Strategy ................................................................................ 7

4.1 Key Infrastructure ................................................................................................................... 7

4.1.1 Leachate Collection and Extraction System .............................................................. 7

4.1.2 Leachate Evaporation Ponds ..................................................................................... 8

4.2 Leachate Generation Modelling ............................................................................................. 8

4.2.1 Input Data.................................................................................................................. 9

4.2.2 Results ..................................................................................................................... 12

4.3 Water Balance Assessment ................................................................................................... 13

4.3.1 System Inputs .......................................................................................................... 13

4.3.2 System Outputs ....................................................................................................... 13

4.3.3 Assessment Results ................................................................................................. 14

4.4 Operational Management and Monitoring Strategy ............................................................ 14

5 Green Waste Leachate Management Strategy ..................................................................... 16

5.1 Key Infrastructure ................................................................................................................. 16


TW18004 - Leachate Management Plan.1a July 2018 | Page iii

5.2 Water Balance Assessment ................................................................................................... 16

5.2.1 System Inputs .......................................................................................................... 16

5.2.2 System Outputs ....................................................................................................... 17

5.2.3 Assessment Results ................................................................................................. 17

5.3 Operational Management and Monitoring Strategy ............................................................ 17

6 References ......................................................................................................................... 18

Figures ....................................................................................................................................... 19

Tables Table 2-1: Groundwater Bore Characteristics

Table 3-1: Average Maximum and Minimum Temperatures (°C) at Onslow Airport

Table 3-2: Rainfall Depth at Onslow Airport in Millimetres (mm)

Table 3-3: Pan Evaporation Data for Onslow Area in Millimetres (mm)

Table 3-4: Relative Humidity Data at Onslow Airport

Table 3-5: Annual Wind Speed and Direction Data at Onslow Airport

Table 4-1: Summary of Soil & Material Characteristics

Table 4-2: Summary of Installation Quality Parameters

Table 4-3: HELP Model Results

Table 4-4: Leachate Evaporation Pond Design Characteristics

Table 5-1: Green Waste Drainage Pond Design Characteristics

Figures Figure 1: Locality Plan

Figure 2: Topography

Figure 3: Groundwater Monitoring Bore Locations


TW18004 - Leachate Management Plan.1a July 2018 | Page iv

Appendices : Drawings

: HELP Model

: Water Balance Model



1 Introduction

Talis Consultants Pty Ltd (Talis) was commissioned by the Shire of Ashburton (the Shire) to prepare a

Leachate Management Plan (LMP) for the Pilbara Regional Waste Management Facility (the Site)

that summarises the strategy for managing leachate during the operational and post-closure phases

of the project. The LMP is also provided to support the approval documentation.

1.1 Background

The Shire is progressing with the development of a new regional waste management facility located

at 150 Onslow Road, Thalandji, Western Australia as shown in Figure 1. With the rapid increase in

industrial development and its associated growth within the Shire and Pilbara Region, there will be a

significant increase in the volume of waste generated. Therefore, the Shire identified the need for

the establishment of a new facility that can meet the waste management needs of Onslow and the

wider Pilbara region.

The Site will provide a range of waste management services including sustainable initiatives such as

reuse, recycling and recovery as well as treatment and disposal. The proposed Class IV facility and its

associated infrastructure will be designed and constructed in accordance with the Environmental

Protection Authority (EPA) Victoria Best Practice Environmental Management Guidelines for the

Siting, Design, Operation and Rehabilitation of Landfills (August 2015) (Best Practice Landfill

Guidelines). It will consist of a double composite lined landfill with a leachate collection system that

will accept up to Class IV waste types. The proposed Green Waste Processing Area will be designed

and constructed in accordance with the Department of Water (DOW) Water Quality Protection Note

90: Organic Material – Storage and Recycling (June 2011) (WQPN90) and will cater for the treatment

of green waste through mulching. This Area will consist of a low permeability hardstand for the

mulching operations. The hardstand will slope towards a green waste drainage pond, which will

capture any surface water that comes into contact with the stockpiled green waste.

1.2 Purpose

The LMP summarises the application of best practice leachate management systems in the design of

the Site. A key aspect of this document is to provide engineering information regarding assumptions,

calculations and models implemented as part of the design works. The plan also outlines the

leachate management requirements as well as necessary infrastructure and justification of

implemented best practice design principles. The LMP contains the following elements:

Site Description;

Local Climate Data;

Landfill Leachate Management Strategy;

o Key Infrastructure;

o Leachate Generation Modelling;

o Water Balance Assessment;

o Operational Management and Monitoring Strategy

Green Waste Leachate Management Strategy;



o Key Infrastructure; and

o Operation Management and Monitoring Strategy.



2 Site Description

2.1 Topography

The Site is relatively flat, with a gentle slope across the sand plain towards the north-west and the

Indian Ocean. The Site topography ranges from 17 to 13 metres (m) Australian Height Datum (AHD)

on the lower sand plain to 40mAHD along the crest of the sand ridge. A number of surface

depressions of various sizes are distributed across the sand ridge. The Site topography is provided in

Figure 1.

2.2 Groundwater

A Phase 1 Hydrogeological Investigation was undertaken in December 2017 to assess both the

groundwater regime beneath the Site and the risk to environmental values and adjacent properties

in relation to the proposed development of a waste management facility at the Site. A total of

thirteen soil bores were drilled into the regional groundwater aquifer, with some converted into

groundwater monitoring wells and the rest converted into combined groundwater monitoring wells

and landfill gas wells. The location of these monitoring bores is provided in Figure 2.

The details of the monitoring bores around the landfill, including the groundwater depth in metres

below ground level (mbgl), are summarised in Table 2-1.

Table 2-1: Groundwater Bore Characteristics

Bore ID Average Groundwater

Depth (mbgl)

Ground Level Elevation

(mAHD)

Average Groundwater

Depth (mAHD)

BH01 6.84 18.74 11.90

BH02 9.33 20.94 11.60

BH03 5.43 16.73 11.30

BH04 6.15 12.76 6.60

BH05 6.02 12.52 6.50

BH10 20.73 31.54 10.81

BH11 17.42 26.71 9.29

BH12 6.16 17.15 10.99

BH13 6.27 15.78 9.52

BH14 7.18 16.26 9.08

BH15 5.61 14.38 8.76

BH16 6.06 15.63 9.57

BH17 6.33 16.82 10.49

Note: The Average Groundwater Depth is based on monthly static water level measurements from January through July (excluding

February) 2018.



3 Local Climate Data

The local and regional climate data sources utilised in designing the leachate management system at

the Site include the following:

Rainfall;

Temperature;

Pan Evaporation;

Other key climate data including:

o Solar Radiation;

o Relative Humidity; and

o Wind Speed.

Historic weather data was sourced from the Bureau of Meteorology (BOM) website utilising the

Onslow Airport weather station data (Station ID: 005017): http://www.bom.gov.au/climate/data/.

The station is approximately 4 kilometres (km) from the coast and about 30km from the Site.

3.1 Temperature

The climate of the Onslow area is considered to be a grassland climate and arid with a hot, humid

summer zone. Table 3-1 shows the mean minimum and maximum temperature at the Onslow

Airport from 1940 to 2017.

Table 3-1: Average Maximum and Minimum Temperatures (°C) at Onslow Airport

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

Minimum 24.4 25.0 24.2 21.4 17.4 14.3 13.0 13.6 15.4 17.9 20.1 22.4 19.1

Maximum 36.4 36.3 36.1 33.9 29.3 26.0 25.4 27.3 30.1 32.9 34.4 35.9 32.0

As shown above, the lowest minimum mean temperature for Onslow is 13.0°C during the winter

months and highest maximum mean temperature is 36.4°C during the summer months.

3.2 Rainfall

Being an arid zone, the wet season for the Pilbara region occurs from December to April each year.

Table 3-2 presents the summary of rainfall records observed at Onslow Airport from 1940 to 2017.

Table 3-2: Rainfall Depth at Onslow Airport in Millimetres (mm)

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

Average 38.6 61.0 72.0 11.4 48.6 45.5 20.3 8.6 1.4 0.8 2.8 3.4 314.4

90th

Percentile* 112.4 179.2 248.6 28.9 111.8 111.6 51.3 30.0 2.2 1.6 4.7 6.7 540.5

Recorded

Highest† 84.8 284.2 68.8 32 16.8 90 46.4 0.8 0.2 0.2 0 0 624.2

Note: *The year 1942 represents the 90th percentile rainfall.

†The year 2011 had the highest recorded rainfall in recent history, within the past 10 years.

http://www.bom.gov.au/climate/data/



The mean annual rainfall for Onslow is reported as 314.4 millimetres (mm). Regionally, the

Ashburton River Catchment mean annual rainfall varies from 230mm to 400mm. Larger rainfall

events are typically associated with tropical cyclones and large low pressure systems that most

frequently affect the region between January and March.

3.3 Pan Evaporation

The Onslow Airport weather station does not record mean daily evaporation. Therefore, monthly

evaporation rates were interpolated from BOM’s 1975-2005 Average Pan Evaporation Map

(http://www.bom.gov.au/jsp/ncc/climate_averages/evaporation/index.jsp?#maps).

The approximate average daily pan evaporation rates were calculated from the monthly rates. The

pan evaporation data for the Onslow has been provided in Table 3-3.

Table 3-3: Pan Evaporation Data for Onslow Area in Millimetres (mm)

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

Monthly 350 300 300 300 175 125 125 175 250 300 350 400 3,150

Daily Average 11.3 10.7 9.7 10.0 5.6 4.2 4.0 5.6 8.3 9.7 11.7 12.9 8.6

The daily average pan evaporation ranges from 4.0mm to 12.9mm and monthly from 125mm to

400mm. The total annual pan evaporation for Onslow is reported as 3,150mm.

3.4 Other Key Climate Data

The other key climate data that will be required for the design of the leachate management system

is solar radiation, relative humidity and wind speed.

Solar radiation is the measure of radiant energy emitting from the sun and falling on a horizontal

surface. It can range from 1.5 mega joules per square metre (MJ/m2) to 32.1 MJ/m2 in Onslow.

Annual average solar radiation is in the order of 22.5 MJ/m2.

Relative humidity is an indicator of the likelihood of rainfall and a key factor in determining the rate

of evapotranspiration. Table 3-4 provides a summary of the relative humidity observed at Onslow

Airport.

Table 3-4: Relative Humidity Data at Onslow Airport

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

Average 9am

relative humidity (%) 54 59 58 55 58 63 61 54 46 42 44 47

Average 3pm

relative humidity (%) 51 53 49 44 45 45 44 39 38 38 43 46

Monthly

Average (%) 53 56 54 50 52 54 53 47 42 40 44 47

http://www.bom.gov.au/jsp/ncc/climate_averages/evaporation/index.jsp?#maps



According to BOM, wind speed is the average speed of the wind over a ten minute period at

approximately ten metres above the surface. It is another key factor in determining the rate of

evapotranspiration. Table 3-5 outlines a summary of the average wind speed and direction for a

given year at Onslow Airport from 1940 to 2017.

Table 3-5: Annual Wind Speed and Direction Data at Onslow Airport

Description Wind Speed (km/h) Prevailing Wind Direction

Mean 9am Conditions 17 S-SE

Mean 3pm Conditions 23 W-NW

Mean Daily Conditions 20



4 Landfill Leachate Management Strategy

Leachate may be generated through waste decomposition in the landfill, liquids within in the waste

deposited, surface water inflow, groundwater intrusion, and the percolation of rainfall through

waste. To limit leachate production, the operational procedures of the landfill will closely align with

Best Practice Landfill Guidelines. The exposed operational area of the landfill will be kept to a

minimum and the landfill will be progressively capped as each landfill cell reaches its final fill profile.

Further measures to reduce the generation of leachates will include:

An effective surface water management plan intended to control and divert surface water

away from the landfill, particularly the active operational areas; and

A progressive capping plan.

The following sections discuss the key infrastructure that will manage the leachate generated at the

Site and how it was designed through modelling the estimated volume of leachate that will be

produced.

4.1 Key Infrastructure

4.1.1 Leachate Collection and Extraction System

Due to the nature of hazardous materials, a Class IV landfill lining system is required to provide a

high level of protection to the environment. Therefore, a double composite lining system is

proposed with a leachate collection layer above the primary lining system and a leak detection layer

above the secondary lining system. In accordance with Best Practice Landfill Guidelines, the leachate

collection and extraction system has been designed for the diversion of leachate, which has soaked

through the waste layers of the landfill, out of each landfill cell and into the leachate pond system

for treatment through evaporation.

As part of the primary basal lining system of each landfill cell, a layer of permeable gravel will collect

and guide the leachate towards a network of perforated high density polyethylene (HDPE) pipes. The

leachate collection system will consist of a 225mm primary collection pipe and a series of 160mm

secondary pipes spaced approximately 25m apart directing leachate towards a collection sump and

extraction point. The sump contains a 450mm side riser pipe to assist in the removal of leachate

from the cell and transfer to the evaporation pond system. The leachate will be transferred via a

solid HDPE pipe rising main to the evaporation ponds.

In the event the integrity of the primary layer is compromised, a secondary leachate

detection/collection system will direct potential leakage/seepage to a secondary extraction sump.

The proposed secondary leachate detection/collection system consists of a drainage geocomposite

sandwiched between the primary and secondary composite lining systems to direct leachate

seepage towards a secondary extraction sump.

The leachate collection system will be installed in a manner that does not damage the proposed

composite lining system with grades on all slopes and surfaces constructed as per Best Practice

Landfill Guidelines.



The hydraulic head of leachate over the landfill liner surface will be managed during the landfill

operation in accordance with Best Practice Landfill Guidelines requirements through extraction of

leachate from the sump. Working together, the leachate collection layer using a combination of

gravel and collection pipes offers an effective long-term solution for the extraction of leachate from

the base of the landfill.

Leachate levels on the landfill base will be maintained as low as reasonably practicable, to heights as

modelled / identified in the Phase 2 Hydrogeological Risk assessment.

4.1.2 Leachate Evaporation Ponds

To manage leachate, evaporation ponds will be constructed southwest of the landfill development

footprint. To prevent leachate stored in the evaporation ponds from percolating into the

groundwater system, the ponds will be lined according to Best Practice Landfill Guidelines:

2mm HDPE Geomembrane;

Secondary 2mm HDPE Geomembrane; and

300mm Engineered Subgrade.

The evaporation ponds must be able to manage the maximum leachate volumes potentially

generated and extracted from the landfill as well as any rainfall into the ponds during consecutive

wet years. A 0.5m freeboard must also be maintained as per the Best Practice Landfill Guidelines.

During particularly wet weather periods, leachate can be recirculated back through the waste of the

operational landfill.

The pond crest will be engineered to be a minimum of 0.5m above the natural topographic ground

levels to prevent surface water runoff from the Site entering the ponds. The pond system will also be

securely fenced to prevent unauthorised access, and as a health and safety precaution, safety

netting will be installed on the interior face of each evaporation pond to provide an egress point.

4.2 Leachate Generation Modelling

To determine the volume of leachate generated, the Hydrologic Evaluation of Landfill Performance

(HELP 3.95D) software package was utilised. The HELP program is a quasi-two-dimensional

hydrologic model of water movement across, into, through and out of landfills. It requires weather,

soil and design data and uses solution techniques that account for the effects of surface storage,

runoff, infiltration, evapotranspiration, vegetative growth, soil moisture storage, and seepage

through soil, geomembrane or composite liners.

The maximum potential area for the active generation of leachate is when the three largest landfill

cells adjacent to each other are considered operational (i.e. contain waste and final capping works

have not commenced).

The following sections outline the details for the modelling in the HELP program.



4.2.1 Input Data

The data required for the HELP model includes rainfall, temperature, relative humidity and solar

radiation. Although Onslow Airport weather records date back to 1940, solar radiation data has only

been recorded since 2007. Therefore, the climate records from years 2007 to 2018 (11 years) were

used in the HELP model to determine leachate generation.

4.2.1.1 Evapotranspiration

Evapotranspiration was calculated in the HELP model based on the transfer and balance of energy in

the environment which included relative humidity and average daily wind speed. Soil evaporative

zone depth, maximum leaf area index and growing season data were also included in the model.

The evaporative zone depth was defined as 2.5 centimetres (cm). In reality, the evaporative zone

depth would vary due to changes in compaction rates, exposure to the weather, type of waste and

initial moisture content. The operational evaporative zone depth was elected conservatively as to

determine the upper limit of leachate which would require management.

The HELP model applies a maximum leaf area index to define the ratio of the leaf area of actively

transpiring vegetation. The operational phase of the landfill was modelled with zero (0) representing

bare ground leaf area index.

In the HELP model user guidelines, the growing season for grasses is defined as when the normal

mean daily temperature rises above 10°C to 12.8°C. According to the climate data for Onslow, the

normal mean daily temperature is always above 12.8°C. The wet season for the Pilbara region

occurs from December to April each year, but due to arid-desert like conditions there is no reliable

growing season.

Fire, grazing and weather interact in complex ways to affect land condition. Controlled burning of

spinifex pastures provides the most benefit to areas with an average annual rainfall of at least 200

millimetres (mm). Spinifex germination and re-establishment can reach 6-8cm in diameter about

three months after germinating rains, if soil moisture levels are sufficient to sustain continuing

growth (Department of Primary Industries and Regional Development - DPIRD, 2018). Therefore for

the purpose of modelling, the growing season was defined as occurring between December and July.

4.2.1.2 Curve Number

HELP modelling requires a user-defined Curve Number (CN) which is an empirical parameter for

predicting runoff, the HELP user guide provides a table for typical runoff curves based on the stand

of grass and soil texture. The lowest runoff curve number accepted in the HELP model, 0.1, was

assigned to represent little to no runoff occurring during storm events.

4.2.1.3 Landfill Design

The landfill footprint covers a total area of 13.88 hectares (ha). The three largest adjacent cells cover

a combined area of 4.4ha. These cells represent the maximum potential area for active generation of

leachate if they were simultaneously operational with no final cap.



Due to the nature of hazardous materials, a Class IV landfill lining system is required to provide a

high level of protection to the environment. Therefore, a double composite lining system is

proposed with a leachate collection layer above the primary lining system, and a leak detection layer

above the secondary lining system. The silty/clayey ‘Pindan Sand’ as identified in the geotechnical

investigation at the Site will be utilised as an engineered attenuation layer as part of the basal lining

design below the geosynthetic lining system.

The proposed lining system to meet the requirements of the Best Practice Landfill Guidelines is

outlined below:

Primary Lining System:

o Best Practice Landfill Guidelines infers that the top of the leachate collection layer

should have a geotextile layer to prevent fine particles from the waste mass filtering into

the gravel and blocking the pore space and adversely affecting the permeability.

o Above the composite lining system, a 300mm thick layer of permeable gravel with an

associated network of perforated collection pipes will act as the leachate collection

system. The composite lining system will be protected from the leachate collection

system and overlying materials with a non-woven protection/cushion geotextile. The

protection/cushion geotextile will be specified to account for the grading of the gravel

and long term loading from waste disposal operations;

o 2mm High Density Polyethylene (HDPE) geomembrane will act as an artificial sealing

liner to form the upper part of the primary lining system; and

o A low permeability Geosynthetic Clay Liner (GCL) consisting of layer of bentonite needle

punched between two layers of geotextiles.

Secondary Lining System:

o A Leak Detection Layer consisting of a drainage geocomposite to direct potential

seepage to a secondary extraction/monitoring sump;

o 2mm HDPE geomembrane will overlie the lower GCL as an artificial sealing liner to form

the upper part of the secondary lining system;

o A low permeability GCL consisting of layer of bentonite needle punched between two

layers of geotextiles, will be installed in direct contact with the engineered attenuation

liner as part of the secondary composite lining system; and

o A minimum 500mm thick engineered attenuation layer sourced from onsite ‘Pindan

Sand’ will be constructed on the base and side slopes of the landfill to form an

engineered attenuation layer above the naturally occurring in situ attenuation soils.

The double composite basal containment liner as previously described was utilised to define the soil

and material characteristics within the model. The default soil data/manual inputs and material

characteristics for the layer properties utilised in the simulations are shown in Table 4-1.



Table 4-1: Summary of Soil & Material Characteristics

Layer No. Layer Type Description Thickness

Total Pore

Volume

Field

Capacity

Wilting

Point

Sat. Hydraulic

Conductivity

(cm) (Vol/Vol) (Vol/Vol) (Vol/Vol) (cm/s)

1 Vertical Percolation Layer Waste 250 0.671 0.292 0.077 0.001

2 Vertical Percolation Layer Separation Geotextile 0.3 0.85 0.01 0.005 10

3 Lateral Drainage Layer Leachate Drainage/Gravel 30 0.397 0.032 0.013 0.1

4 Geomembrane HDPE Geomembrane 0.2 - - - 2.0 × 10-13

5 Vertical Percolation Layer Geosynthetic Clay Liner (GCL) 0.6 0.75 0.747 0.4 3.0 × 10-9

6 Lateral Drainage Layer Drainage Geocomposite 0.6 0.85 0.01 0.005 2.6

7 Geomembrane HDPE Geomembrane 0.2 - - - 2.0 × 10-13

8 Vertical Percolation Layer Geosynthetic Clay Liner (GCL) 0.6 0.75 0.747 0.4 3.0 × 10-9

9 Vertical Percolation Layer Engineered Attenuation Layer 50 0.501 0.284 0.135 1.9 × 10-4

10 Vertical Percolation Layer In situ Pindan Sand 250 0.463 0.232 0.116 3.7 × 10-4

Note: Liner sloped at 3% into collection pipe as per minimum Best Practice Landfill Guidelines.

Maximum drainage length is 135m.

No recirculation of leachate simulated.

Leachate from lateral drainage layer assumed extracted to evaporation pond.



The HELP model also requires additional user inputs corresponding to the installation quality,

pinhole density, and installation defect density.

Pinhole density is defined as the number of defects with a diameter less than or equal to the

geomembrane thickness. Installation defect density is described as the number of defects with 1cm2

diameter holes, possibly resulting from seaming faults and punctures while the placement quality

represents the closeness of contact between the geomembrane and the drainage limiting soil.

Table 4-2: Summary of Installation Quality Parameters

Placement Quality Pinhole Density

(no. per hectare)

Installation Defects

(no. per hectare)

Excellent 2 2

Good 5 5

Poor 15 15

The assumptions for placement and installation quality as defined by the HELP 3.95D modelling

software is as follows:

Excellent - Assumes exceptional contact between the geomembrane and the adjacent soil

that limits drainage rate;

Good - Assumes good field installation with well-prepared, smooth soil surface and

geomembrane wrinkle control to ensure good contact between the geomembrane and the

adjacent soil that limits drainage rate; and

Poor - Assumes poor field installation with less well-prepared, smooth soil surface and/or

geomembrane wrinkling providing poor contact between the geomembrane and the

adjacent soil that limits drainage rate, resulting in a larger gap for spreading and greater

leakage.

While the placement quality will not have an overall effect on the amount of leachate that is

generated, a ‘Good’ placement quality was adopted for the purposes of this model.

4.2.2 Results

The HELP model assumes Darcian flow by gravity influences through homogeneous soil and waste

layers. It does not consider preferential flow through channels, cracks, root holes or animal burrows.

Geomembranes are assumed to leak primarily through holes in the liner. The model assumes the

holes are uniformly distributed and the head is distributed across the liner. The HELP model does not

consider aging of the liner, and therefore the number and size of the holes do not vary as a function

of time.

Table 4-3 summarises the potential monthly leachate volumes calculated in the HELP model. The

complete model results are provided in Appendix B.



Table 4-3: HELP Model Results

Note: The area assumed to determine the Monthly Volume was 4.4ha or 44,000m2.

The maximum annual volume of leachate that the leachate pond system will be required to manage

is 9,080m3. The highest rates of leachate generation occur during the months when significant

rainfall events from tropical cyclones and large low pressure systems are most likely to arise in the

region.

4.3 Water Balance Assessment

A water balance assessment was utilised to determine the appropriate size of the leachate

evaporation ponds and to assess its subsequent performance. Using a Microsoft Excel algorithm, the

assessment presented a simplified input and output system based on the following:

Inputs: o Leachate inflow o Monthly rainfall

Outputs: o Evaporation

4.3.1 System Inputs

The HELP model leachate input values presented in Table 4-3 were utilised with the monthly rainfall

as part of the water balance assessment for the ponds.

As the region is prone to cyclonic events, it is critical that the evaporation ponds had the capacity to

manage the storm events. The most significant weather events for consideration in the sizing of the

evaporation ponds were the following:

90th percentile annual rainfall; and

Highest annual rainfall within 10 years.

The meteorological data is detailed in Section 3.2. For the 90th percentile rainfall scenario, the

monthly figures observed in 1942 were utilised for the pond catchment volumes, which had an

annual rainfall of 540.6mm. The highest rainfall within the last ten years was 624.2mm and was

observed in 2011 when a major rainfall event occurred in February.

4.3.2 System Outputs

To quantify the amount of leachate evaporated each year, the following parameters were assumed:

The freeboard was set at 0.5m to determine the available operational volume of each pond;

No rainfall within an evaporation pond’s catchment area was lost to run-off;

Leachate

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

Depth

(mm) 23.2 37.0 50.9 29.9 14.4 25.1 17.6 0.4 0.6 0.8 1.0 5.3 206.4

Volume

(m3) 1,019 1,628 2,240 1,317 634 1,106 773 17 28 37 45 235 9,080



No leachate is recirculated into the landfill, all leachate is required to be extracted and

treated in the evaporation ponds;

The actual evaporation rate was assumed to be 80% of the potential pan evaporation rate;

and

For the purpose of the calculations, the evaporation area was set 1.0m from the top of each

pond.

The volumes within the evaporation ponds for a given month included the initial leachate inputs

transferred from the operational landfill cell, the remaining leachate from the previous month (if

any), any further leachate inputs for the month, and the rainfall within the catchment area based on

the rainfall scenario. Once the excess leachate has been evaporated, the evaporation ponds have

been designed to theoretically be empty by the end of spring/beginning of summer for both rainfall

scenarios to allow for inspection, maintenance and cleaning works as necessary.

4.3.3 Assessment Results

It was determined that two evaporation ponds constructed according to Best Practice Landfill

Guidelines were required, to allow for continued operation and staged maintenance to either pond.

Drawing C-120 shows the layout of the evaporation ponds at the Site and has been provided in

Appendix A. The design characteristics of the evaporation ponds are provided in Table 4-4.

Table 4-4: Leachate Evaporation Pond Design Characteristics

Length

(m)

Width

(m)

Height

(m)

Catchment

Area (m2)

Total

Volume (m3)

Maximum

Evaporation Area (m2)

Operational

Volume (m3)

80 56 1.5 4,480 5,843 3,700 4,754

The two evaporation ponds have a combined operational volume of 9,507m3. Modelling verified that

the leachate management system is capable of evaporating the accumulated leachate every

calendar year. During either rainfall scenario, there is an annual two to three month period in which

the leachate ponds are empty and maintenance can occur. The results of the modelling are

provided in Appendix C.

4.4 Operational Management and Monitoring Strategy

The filling of landfill cells will be undertaken in a phased approached, which will ensure leachate

generation is minimised.

As part of the management procedures leachate recirculation back into the waste mass can be

undertaken to aid removal of leachate if pond volumes necessitate. Recirculation is the process of

circulating the leachate from the evaporation pond back into the waste mass and active cells. This

process has several advantages including:

Leachate storage within the waste;

Increased landfill gas generation rate;

Increased waste settlement, leading to more efficient use of landfill void space; and

Accelerated waste degradation and stabilisation.



However, no recirculation has been assumed during the sizing of the evaporation ponds, to ensure

the model was developed with a further element of conservatism.

The leachate collection system will be regularly inspected, maintained and repaired when necessary.

Leachate monitoring will be undertaken on a regular basis to ensure the leachate collection and

extraction system is operating effectively, to determine the head and quality of leachate, and to

ensure compliance with assessment criteria and compliance limits.

To ensure environmental impacts are mitigated and the facility meets licence requirements, regular

environmental monitoring, including leachate, will be undertaken. The details of the monitoring

required are prescribed in the Site’s Operational and Environmental Management Plan (OEMP).



5 Green Waste Leachate Management Strategy

Leachate may be generated through the processing of green waste and by surface water inflow,

which becomes contaminated after contact with the green waste. To limit leachate production, the

operational area of the Green Waste Processing Area will be kept to a minimum, and surface water

inflow will be directed away from this operational area.

The following sections discuss the key infrastructure that will manage the leachate from the Green

Waste Processing Area at the Site and its monitoring and operational management.

5.1 Key Infrastructure

To manage the green waste leachate, a drainage pond will be constructed along the southern

boundary of the Green Waste Processing Area. The processing area will be graded northeast to

southwest with a 1:200 slope gradient to divert surface water run-off into the drainage pond.

The drainage pond will consist of a low permeability compacted subgrade with to prevent leachate

stored in the pond from percolating into the groundwater system. The northern edge of the pond

will be level with the natural topographic ground levels to divert surface water run-off directly into

the pond with minimum associated infrastructure requirements (i.e. surface water swales, pipework,

etc.).

5.2 Water Balance Assessment

According to WQPN90, the drainage pond should be designed to manage a 72hr, 1-in-10 year storm

event and to maintain a sufficient freeboard (considered to be 0.4m) for a 90th percentile rainfall

year. A water balance assessment was utilised to determine the appropriate size of the drainage

pond and to assess its subsequent performance. Using a Microsoft Excel algorithm, the assessment

presented a simplified input and output system based on the following:

Inputs: o Monthly rainfall into the pond o Surface water run-off from the Green

Waste Processing Area

Outputs: o Evaporation

5.2.1 System Inputs

As the region is prone to cyclonic events, it is critical that the drainage pond has the capacity to

manage the storm events. The same rainfall events that were considered for the landfill leachate

pond system, were utilised for the drainage pond (as discussed in Section 4.3.1).

The full allocated area for Green Waste Processing (to allow for future expansion) is 5,000m2, while

it is anticipated that initial operations would encompass only a small percentage of the allocated

area, approximately. 1,500m2. The drainage pond has been sized for the 1,500m2 initial area for the

green waste activities, with a run-off coefficient of 0.5, which is typical for a gravel hardstand.



5.2.2 System Outputs

To quantify the amount of leachate evaporated each year, the following parameters were assumed:

The freeboard was set at 0.4m to determine the available operational volume of each pond;

No rainfall within an evaporation pond’s catchment area was lost to run-off;

The actual evaporation rate was assumed to be 80% of the potential pan evaporation rate;

and

The evaporation area was set at the level representing 75% operational capacity.

The volumes within the drainage pond for a given month included the initial leachate inputs from

the Green Waste Processing Area, the remaining leachate from the previous month (if any), any

further leachate inputs for the month, and the rainfall within the catchment area based on the

rainfall scenario. Once the excess leachate has been evaporated, the drainage pond has been

designed to theoretically be empty by the end of spring/beginning of summer to allow for

inspection, maintenance and cleaning works as necessary.

5.2.3 Assessment Results

The drainage pond for the Green Waste Processing Area is shown on Drawing C-120, and has been

provided in Appendix A. The design characteristics of the drainage pond are provided in Table 5-1.

Table 5-1: Green Waste Drainage Pond Design Characteristics

Length

(m)

Width

(m)

Height

(m)

Side Slope

(V:H)

Catchment

Area (m2)

Total

Volume (m3)

Maximum

Evaporation

Area (m2)

Operational

Volume (m3)

64 19 1.4 1:6 1,310 962 740 481

Modelling verified that the leachate management system is capable of evaporating the accumulated

leachate every calendar year. During the 90th percentile rainfall scenario, there is an annual two to

three month period in which the leachate ponds are empty and maintenance can occur. During a

72hr, 1-in-10 year storm event, approximately 307m3 of rainfall would fall into the drainage pond,

which is less than the operational volume, ensuring no overtopping. If the Green Waste Processing

Area drainage pond was likely to breach freeboard, excess leachate will be pumped into the landfill

leachate evaporation pond system. The results of the modelling are provided in Appendix C.

5.3 Operational Management and Monitoring Strategy

The green waste drainage pond will be regularly inspected, maintained and repaired when

necessary. Consistent monitoring of the leachate level, particularly after a significant rainfall event,

will be undertaken by Site staff. To ensure the sufficient freeboard is maintained, any excess

leachate will be pumped into the landfill leachate evaporation pond system. As green waste

processing operations become more developed, the water balance for the drainage pond will be

reviewed, and if required, the drainage pond will be expanded to accommodate additional volumes

of leachate/run-off.



6 References

Bureau of Meteorology (BOM), Average annual, monthly and seasonal evaporation, ‘Evaporation

Maps’, Australian Government, November 2016, (accessed July 2018).


Bureau of Meteorology (BOM), Climate statistics for Australian locations, ‘Onslow Airport weather

station data (Station ID: 005017)’, 5 July 2018, (accessed July 2018).


Department of Primary Industries and Regional Development (BPIRD), ‘Spinifex rangeland pastures

and fire’, 13 April 2018, (accessed July 2018). https://www.agric.wa.gov.au/rangelands/spinifex-

rangeland-pastures-and-fire

Department of Water (DOW), ‘Water quality protection note 90: Organic material - storage and

recycling’, June 2011. https://www.water.wa.gov.au/__data/assets/pdf_file/0020/4088/99456.pdf

The Hydrologic Evaluation of Landfill Performance (HELP) Model (HELP-D), HELP3.95D, University of

Hamburg.



https://www.agric.wa.gov.au/rangelands/spinifex-rangeland-pastures-and-fire

https://www.agric.wa.gov.au/rangelands/spinifex-rangeland-pastures-and-fire

https://www.water.wa.gov.au/__data/assets/pdf_file/0020/4088/99456.pdf



Figures

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LEGEND

© Talis Co nsu ltan ts P ty Ltd ("Talis") Copyright i n the drawi ngs, i nform at ion a nd data

recorded in th is docum ent ("th e in form ati on") is the property of Talis. T his docum ent and

the i nform ati on are solel y for the use of th e auth orised recipient and

this docu ment m ay not be used, transferred or reprodu ced in whole o r part

for any purpose other than that which it i s supp lied by Talis without

wri tten consent. Talis m akes no representat ion, undertakes no duty an d

accepts no responsibili ty to a ny th ird party who may use or rel y upon thi s

docu ment or the in form ati on.

Yanrey

PannawonnicaOnslow

Red Hill

Cane River

0 40 80 120 16020

km

LOCALITY

LOCALITY PLANLeachate Management Plan

Pilbara Regional Waste

Management Facility

Lot 150 Onslow Road

Talandji, WA 6710

0 4 81 2 3Km

¤ Coor dinate S y stem : GDA 1994 MG A Zone 50

Pro jection: Trans vers e Mer cator, Datum : GDA 1994

Reviewed:

Checked:

Prepared: Date:

Revision:

Sc ale @ A 3:1:200,000

Project No:

Data s our ce: Im ager y - Landgate, 2017. Roads - M ain Roads WA , 2017

Fig

ure

01

Site Boundary

P: PO Box 454, Leederville WA 6903 | A: Level 1 660 Newcastle St, Leederville WA 6007 | T: 1300 251 070 | W: www.ta lisconsultants.com.au

C. Panizza

N King

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,500 LEGEND

© Tal is Co ns ul tants P ty L td ("Ta l is " ) C opy righ t in the d raw ings , in for m ation and d ata

rec ord ed in th is doc um e nt (" the in fo rm atio n") is t he pr opert y o f Ta l is . Th is d oc um en t and

the in fo rm at io n ar e s o le ly for the u s e of the a uthor ise d r ec ip ient a nd

th is doc um ent m a y not be us ed, tr ans fer red or re produ c ed in w hole or pa rt

for a ny pur pos e o ther than t hat w hic h i t is s uppl ied by Tal is w i thout

wr i tten c o ns ent. Ta l is m ak es no r epres e ntation, unde rtak es no du ty and

ac c epts no res po ns ib i l it y to an y th i rd p arty w ho m ay u se or r e ly upo n th is

doc um e nt o r t he in form a tion.

Yanrey

PannawonnicaOnslow

Red Hill

Cane River

0 40 80 120 16020

km

LOCALITY

TOPOGRAPHYLeachate Management Plan


Management Facility

Lot 150 Onslow Road

Talandji, WA 6710

0 125 250 375 500metres

¤ Co o rd in at e Sy st em : G D A 1 99 4 M G A Zon e 5 0

Pro je ct io n: T r an sv e rs e M e rc a to r, Da tu m : G DA 1 99 4

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Fig

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02

Site Boundary

Elevation (mAHD)

P: PO Box 454, Leederv il le WA 6903 | A : Level 1 660 Newcastle St, Leederv il le W A 6007 | T: 1300 251 070 | W : www.ta lisc ons ultants.c om .au

C. P aniz za

N K in g

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TW 18 004

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LEGEND

© Talis Co nsu ltan ts P ty Ltd ("Talis") Copyright i n the drawi ngs, i nform at ion a nd data

recorded in th is docum ent ("th e in form ati on") is the property of Talis. T his docum ent and

the i nform ati on are solel y for the use of th e auth orised recipient and

this docu ment m ay not be used, transferred or reprodu ced in whole o r part

for any purpose other than that which it i s supp lied by Talis without

wri tten consent. Talis m akes no representat ion, undertakes no duty an d

accepts no responsibili ty to a ny th ird party who may use or rel y upon thi s

docu ment or the in form ati on.

Yanrey

PannawonnicaOnslow

Red Hill

Cane River

0 40 80 120 16020

km

LOCALITY

GROUNDWATER MONITORINGBORE LOCATIONS

Leachate Management Plan


Management Facility

Lot 150 Onslow Road

Talandji, WA 6710

0 100 200 300 400 50050metres

¤ Coor dinate S y stem : GDA 1994 MG A Zone 50

Pro jection: Trans vers e Mer cator, Datum : GDA 1994

Reviewed:

Checked:

Prepared: Date:

Revision:

Sc ale @ A 3:1:13,000

Project No:

Data s our ce: Im ager y - Landgate, 2017.

Fig

ure

03

Site Boundary

@AGroundwater Monitoring

Well

P: PO Box 454, Leederville WA 6903 | A: Level 1 660 Newcastle St, Leederville WA 6007 | T: 1300 251 070 | W: www.ta lisconsultants.com.au

C. Panizza

N King

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Level 1 660 Newcastle Street,

Leederville WA 6007

PO Box 454, Leederville WA 6903

T: 1 3 0 0 2 5 1 0 7 0w w w . t a l i s c o n s u l t a n t s . c o m . au

ASSET MANAGEMENT

CIVIL ENGINEERING

ENVIRONMENTAL SERVICES

SPATIAL INTELLIGENCE

WASTE MANAGEMENT



: HELP Model

Good Installation Operational HELP Model Results

****************************************************************************** ****************************************************************************** ** ** ** ** ** HYDROLOGIC EVALUATION OF LANDFILL PERFORMANCE ** ** ** ** HELP Version 3.95 D (10 August 2012) ** ** developed at ** ** Institute of Soil Science, University of Hamburg, Germany ** ** based on ** ** US HELP MODEL VERSION 3.07 (1 NOVEMBER 1997) ** ** DEVELOPED BY ENVIRONMENTAL LABORATORY ** ** USAE WATERWAYS EXPERIMENT STATION ** ** FOR USEPA RISK REDUCTION ENGINEERING LABORATORY ** ** ** ** ** ****************************************************************************** ******************************************************************************

TIME: 11.13 DATE: 24.07.2018

PRECIPITATION DATA FILE: \\server\talis\SECTIONS\Waste\PROJECTS\TW2018\TW18036 - Onslow HRA 2\Data\HELP Simulation\Precipitation\P - 2007 - 2018 (11 years).d4 TEMPERATURE DATA FILE: \\server\talis\SECTIONS\Waste\PROJECTS\TW2018\TW18036 - Onslow HRA 2\Data\HELP Simulation\Temperature\T- 2007 - 2018 (11 years).d7 SOLAR RADIATION DATA FILE: \\server\talis\SECTIONS\Waste\PROJECTS\TW2018\TW18036 - Onslow HRA 2\Data\HELP Simulation\Solar Radiation\SR - 2007 - 2018 (11 years).d13 EVAPOTRANSPIRATION DATA F. 1: \\server\talis\SECTIONS\Waste\PROJECTS\TW2018\TW18036 - Onslow HRA 2\Data\HELP Simulation\Evapotranspiration\Evapotranspiration - Operational Updated.d11 SOIL AND DESIGN DATA FILE 1: \\server\talis\SECTIONS\Waste\PROJECTS\TW2018\TW18036 - Onslow HRA 2\Data\HELP Simulation\Layers\Layers - 5 5 Good - Operational Updated.d10 OUTPUT DATA FILE: \\server\talis\SECTIONS\Waste\PROJECTS\TW2018\TW18036 - Onslow HRA 2\Data\HELP Simulation\Simulation Results\Good Installation Operational Updated.out DAILY OUTPUT DATA FILE: \\server\talis\SECTIONS\Waste\PROJECTS\TW2018\TW18036 - Onslow HRA 2\Data\HELP Simulation\Simulation Results\Good Installation Operational Updated.DAY MONTHLY OUTPUT DATA FILE: \\server\talis\SECTIONS\Waste\PROJECTS\TW2018\TW18036 - Onslow HRA 2\Data\HELP Simulation\Simulation Results\Good Installation Operational Updated.MON YEARLY OUTPUT DATA FILE: \\server\talis\SECTIONS\Waste\PROJECTS\TW2018\TW18036 - Onslow HRA 2\Data\HELP Simulation\Simulation Results\Good Installation Operational Updated.YR

COLUMNS OF DAILY OUTPUT DATA FILE:

1 DATE (yyyymmdd) 2 AIR TEMPERATURE (* INDICATES FREEZING TEMPERATURES) 3 FROZEN SOIL STATE (* INDICATES FROZEN SOIL) 4 PRECIPITATION (MM) 5 RUNOFF (MM) 6 POTENTIAL EVAPOTRANSPIRATION (MM) 7 ACTUAL EVAPOTRANSPIRATION (MM) 8 WATER CONTENT OF THE EVAPORATIVE ZONE (MM) 9 HEAD #1: AVERAGE HEAD ON TOP OF LAYER 4 (CM) 10 DRAIN #1: LATERAL DRAINAGE FROM LAYER 3 (RECIRC. + COLLECT.) (MM) 11 LEAK #1: PERCOLATION/LEAKAGE THROUGH LAYER 4 (MM) 12 HEAD #2: AVERAGE HEAD ON TOP OF LAYER 7 (CM) 13 DRAIN #2: LATERAL DRAINAGE FROM LAYER 6 (RECIRC. + COLLECT.) (MM) 14 LEAK #2: PERCOLATION/LEAKAGE THROUGH LAYER 7 (MM) 15 LEAK #3: PERCOLATION/LEAKAGE THROUGH LAYER 10 (MM)

COLUMNS OF MONTHLY OUTPUT DATA FILE:

1 DATE OF ULTIMO (yyyymmdd) 2 PRECIPITATION (MM) 3 RUNOFF (MM) 4 POTENTIAL EVAPOTRANSPIRATION (MM) 5 ACTUAL EVAPOTRANSPIRATION (MM) 6 HEAD #1: AVERAGE HEAD ON TOP OF LAYER 4 (CM) 7 DRAIN #1: LATERAL DRAINAGE FROM LAYER 3 (WITHOUT RECIRC.) (MM) 8 RECIRC#1: LAT. DRAINAGE RECIRCULATED FROM LAYER 3 INTO L. 1 (MM)

Page 1

Good Installation Operational HELP Model Results 9 LEAK #1: PERCOLATION/LEAKAGE THROUGH LAYER 4 (MM) 10 HEAD #2: AVERAGE HEAD ON TOP OF LAYER 7 (CM) 11 DRAIN #2: LATERAL DRAINAGE FROM LAYER 6 (WITHOUT RECIRC.) (MM) 12 RECIRC#2: LAT. DRAINAGE RECIRCULATED FROM LAYER 6 INTO L. 1 (MM) 13 LEAK #2: PERCOLATION/LEAKAGE THROUGH LAYER 7 (MM) 14 LEAK #3: PERCOLATION/LEAKAGE THROUGH LAYER 10 (MM)

COLUMNS OF YEARLY OUTPUT DATA FILE:

1 DATE OF ULTIMO (yyyy1231) 2 PRECIPITATION (MM) 3 RUNOFF (MM) 4 POTENTIAL EVAPOTRANSPIRATION (MM) 5 ACTUAL EVAPOTRANSPIRATION (MM) 6 DRAIN #1: LATERAL DRAINAGE FROM LAYER 3 (WITHOUT RECIRC.) (MM) 7 RECIRC#1: LAT. DRAINAGE RECIRCULATED FROM LAYER 3 INTO L. 1 (MM) 8 LEAK #1: PERCOLATION/LEAKAGE THROUGH LAYER 4 (MM) 9 DRAIN #2: LATERAL DRAINAGE FROM LAYER 6 (WITHOUT RECIRC.) (MM) 10 RECIRC#2: LAT. DRAINAGE RECIRCULATED FROM LAYER 6 INTO L. 1 (MM) 11 LEAK #2: PERCOLATION/LEAKAGE THROUGH LAYER 7 (MM) 12 LEAK #3: PERCOLATION/LEAKAGE THROUGH LAYER 10 (MM) 13 CHANGE IN TOTAL WATER STORAGE (MM) 14 CHANGE IN SOIL WATER STORAGE (MM) 15 CHANGE IN INTERCEPTION WATER STORAGE (MM) 16 CHANGE IN SNOW WATER STORAGE (MM) 17 ANNUAL WATER BUDGET BALANCE (MM)

******************************************************************************

TITLE: Onslow Landfill Good Operational

******************************************************************************

WEATHER DATA SOURCES ------------------------------------------------------------------------------

NOTE: PRECIPITATION DATA FOR Onslow Western Australia WAS ENTERED FROM A TEXT FILE.

NOTE: TEMPERATURE DATA FOR Onslow Western Australia WAS ENTERED FROM A TEXT FILE.

NOTE: SOLAR RADIATION DATA FOR Onslow Western Australia WAS ENTERED FROM A TEXT FILE.

******************************************************************************

LAYER DATA 1 ------------------------------------------------------------------------------

VALID FOR 11 YEARS

NOTE: INITIAL MOISTURE CONTENT OF THE LAYERS AND SNOW WATER WERE COMPUTED AS NEARLY STEADY-STATE VALUES BY THE PROGRAM.

LAYER 1 --------

TYPE 1 - VERTICAL PERCOLATION LAYER MATERIAL TEXTURE NUMBER 18 THICKNESS = 250.00 CM POROSITY = 0.6710 VOL/VOL FIELD CAPACITY = 0.2920 VOL/VOL

Page 2

Good Installation Operational HELP Model Results WILTING POINT = 0.0770 VOL/VOL INITIAL SOIL WATER CONTENT = 0.2898 VOL/VOL EFFECTIVE SAT. HYD. CONDUCT.= 0.1000E-02 CM/SEC NOTE: SATURATED HYDRAULIC CONDUCTIVITY IS MULTIPLIED BY 1.80 FOR ROOT CHANNELS IN TOP HALF OF EVAPORATIVE ZONE.

LAYER 2 --------

TYPE 1 - VERTICAL PERCOLATION LAYER MATERIAL TEXTURE NUMBER 20 THICKNESS = 0.30 CM POROSITY = 0.8500 VOL/VOL FIELD CAPACITY = 0.0100 VOL/VOL WILTING POINT = 0.0050 VOL/VOL INITIAL SOIL WATER CONTENT = 0.0234 VOL/VOL EFFECTIVE SAT. HYD. CONDUCT.= 10.00 CM/SEC

LAYER 3 --------

TYPE 2 - LATERAL DRAINAGE LAYER MATERIAL TEXTURE NUMBER 21 THICKNESS = 30.00 CM POROSITY = 0.3970 VOL/VOL FIELD CAPACITY = 0.0320 VOL/VOL WILTING POINT = 0.0130 VOL/VOL INITIAL SOIL WATER CONTENT = 0.0320 VOL/VOL EFFECTIVE SAT. HYD. CONDUCT.= 0.3000 CM/SEC SLOPE = 3.00 PERCENT DRAINAGE LENGTH = 135.0 METERS

LAYER 4 --------

TYPE 4 - FLEXIBLE MEMBRANE LINER MATERIAL TEXTURE NUMBER 35 THICKNESS = 0.20 CM EFFECTIVE SAT. HYD. CONDUCT.= 0.2000E-12 CM/SEC FML PINHOLE DENSITY = 5.00 HOLES/HECTARE FML INSTALLATION DEFECTS = 5.00 HOLES/HECTARE FML PLACEMENT QUALITY = 3 - GOOD

LAYER 5 --------

TYPE 1 - VERTICAL PERCOLATION LAYER MATERIAL TEXTURE NUMBER 17 THICKNESS = 0.60 CM POROSITY = 0.7500 VOL/VOL FIELD CAPACITY = 0.7470 VOL/VOL WILTING POINT = 0.4000 VOL/VOL INITIAL SOIL WATER CONTENT = 0.7470 VOL/VOL EFFECTIVE SAT. HYD. CONDUCT.= 0.3000E-08 CM/SEC

LAYER 6 --------

TYPE 2 - LATERAL DRAINAGE LAYER MATERIAL TEXTURE NUMBER 34 THICKNESS = 0.60 CM POROSITY = 0.8500 VOL/VOL FIELD CAPACITY = 0.0100 VOL/VOL WILTING POINT = 0.0050 VOL/VOL INITIAL SOIL WATER CONTENT = 0.0100 VOL/VOL EFFECTIVE SAT. HYD. CONDUCT.= 33.00 CM/SEC

Page 3

Good Installation Operational HELP Model Results SLOPE = 3.00 PERCENT DRAINAGE LENGTH = 135.0 METERS

LAYER 7 --------

TYPE 4 - FLEXIBLE MEMBRANE LINER MATERIAL TEXTURE NUMBER 35 THICKNESS = 0.20 CM EFFECTIVE SAT. HYD. CONDUCT.= 0.2000E-12 CM/SEC FML PINHOLE DENSITY = 5.00 HOLES/HECTARE FML INSTALLATION DEFECTS = 5.00 HOLES/HECTARE FML PLACEMENT QUALITY = 3 - GOOD

LAYER 8 --------


LAYER 9 --------


LAYER 10 --------


******************************************************************************

GENERAL DESIGN AND EVAPORATIVE ZONE DATA 1 ------------------------------------------------------------------------------

VALID FOR 11 YEARS

NOTE: SCS RUNOFF CURVE NUMBER WAS USER-SPECIFIED.

SCS RUNOFF CURVE NUMBER = 0.10 FRACTION OF AREA ALLOWING RUNOFF = 0.0 PERCENT AREA PROJECTED ON HORIZONTAL PLANE = 4.4000 HECTARES EVAPORATIVE ZONE DEPTH = 2.5 CM INITIAL WATER IN EVAPORATIVE ZONE = 0.193 CM UPPER LIMIT OF EVAPORATIVE STORAGE = 1.678 CM

Page 4

Good Installation Operational HELP Model Results FIELD CAPACITY OF EVAPORATIVE ZONE = 0.730 CM LOWER LIMIT OF EVAPORATIVE STORAGE = 0.193 CM SOIL EVAPORATION ZONE DEPTH = 2.5 CM INITIAL SNOW WATER = 0.000 CM INITIAL INTERCEPTION WATER = 0.000 CM INITIAL WATER IN LAYER MATERIALS = 146.532 CM TOTAL INITIAL WATER = 146.532 CM TOTAL SUBSURFACE INFLOW = 0.00 MM/YR

******************************************************************************

EVAPOTRANSPIRATION DATA 1 ------------------------------------------------------------------------------

VALID FOR 11 YEARS

NOTE: EVAPOTRANSPIRATION DATA WAS OBTAINED FROM Onslow Western Australia STATION LATITUDE = -21.67 DEGREES MAXIMUM LEAF AREA INDEX = 1.00 START OF GROWING SEASON (JULIAN DATE) = 335 END OF GROWING SEASON (JULIAN DATE) = 212 EVAPORATIVE ZONE DEPTH = 2.5 CM AVERAGE ANNUAL WIND SPEED = 20.32 KPH AVERAGE 1ST QUARTER RELATIVE HUMIDITY = 54.0 % AVERAGE 2ND QUARTER RELATIVE HUMIDITY = 52.0 % AVERAGE 3RD QUARTER RELATIVE HUMIDITY = 47.0 % AVERAGE 4TH QUARTER RELATIVE HUMIDITY = 43.0 %

******************************************************************************

*******************************************************************************

MONTHLY TOTALS (MM) FOR YEAR 2007 -------------------------------------------------------------------------------

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

PRECIPITATION 0.4 0.0 19.6 15.2 3.2 0.0 43.4 0.6 0.0 0.2 0.0 0.0

RUNOFF 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

POTENTIAL EVAPOTRANSPIRATION 354.11 311.12 306.67 267.42 230.92 192.66 208.29 255.15 289.85 338.56 363.91 357.59

ACTUAL EVAPOTRANSPIRATION 0.40 0.00 2.74 3.72 4.33 3.62 17.69 4.06 0.00 0.20 0.00 0.00

LATERAL DRAINAGE COLLECTED 0.000 0.000 0.637 11.884 10.884 0.015 FROM LAYER 3 19.138 3.291 0.000 0.000 0.000 0.000

LATERAL DRAINAGE RECIRCULATED 0.000 0.000 0.000 0.000 0.000 0.000 FROM LAYER 3 INTO L. 1 0.000 0.000 0.000 0.000 0.000 0.000

PERCOLATION/LEAKAGE THROUGH 0.000 0.000 0.000 0.000 0.000 0.000 LAYER 4 0.000 0.000 0.000 0.000 0.000 0.000




PERCOLATION/LEAKAGE THROUGH 0.000 0.000 0.000 0.000 0.000 0.000

Page 5

Good Installation Operational HELP Model Results LAYER 10 0.000 0.000 0.000 0.000 0.000 0.000

------------------------------------------------------------------------------- MONTHLY SUMMARIES FOR DAILY HEADS (CM) -------------------------------------------------------------------------------

AVERAGE DAILY HEAD ON 0.000 0.000 0.018 0.344 0.305 0.000 TOP OF LAYER 4 0.536 0.092 0.000 0.000 0.000 0.000

STD. DEVIATION OF DAILY 0.000 0.000 0.036 0.465 0.457 0.000 HEAD ON TOP OF LAYER 4 0.510 0.170 0.000 0.000 0.000 0.000



*******************************************************************************

*******************************************************************************

ANNUAL TOTALS FOR YEAR 2007 -------------------------------------------------------------------------------

MM CU. METERS PERCENT ---------- ---------- ------- PRECIPITATION 82.60 3634.400 100.00

RUNOFF 0.000 0.000 0.00

POTENTIAL EVAPOTRANSPIRATION 3476.242 152954.641

ACTUAL EVAPOTRANSPIRATION 36.758 1617.335 44.50

DRAINAGE COLLECTED FROM LAYER 3 45.8499 2017.397 55.51

RECIRC. FROM LAYER 3 INTO L. 1 0.000000 0.000 0.00

PERC./LEAKAGE THROUGH LAYER 4 0.000158 0.007 0.00

AVG. HEAD ON TOP OF LAYER 4 1.0802






CHANGE IN WATER STORAGE -0.008 -0.341 -0.01

SOIL WATER AT START OF YEAR 1474.282 64868.391

SOIL WATER AT END OF YEAR 1474.274 64868.047

INTERCEPTION WATER AT START OF YEAR 0.000 0.000

INTERCEPTION WATER AT END OF YEAR 0.000 0.000

SNOW WATER AT START OF YEAR 0.000 0.000 0.00

SNOW WATER AT END OF YEAR 0.000 0.000 0.00

ANNUAL WATER BUDGET BALANCE 0.0000 0.002 0.00

*******************************************************************************

Page 6


*******************************************************************************



PRECIPITATION 0.2 65.8 201.2 21.2 0.0 47.2 1.0 7.0 0.0 15.0 23.6 3.2

RUNOFF 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00















*******************************************************************************

*******************************************************************************



Page 7

Good Installation Operational HELP Model Results RUNOFF 0.000 0.000 0.00












CHANGE IN WATER STORAGE 2.137 94.049 0.55








*******************************************************************************

*******************************************************************************



PRECIPITATION 275.6 110.0 16.0 0.0 2.8 42.6 5.2 6.2 0.0 0.0 1.4 0.0

RUNOFF 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00







Page 8










*******************************************************************************

*******************************************************************************



RUNOFF 0.000 0.000 0.00

















Page 9

Good Installation Operational HELP Model Results SNOW WATER AT START OF YEAR 0.000 0.000 0.00



*******************************************************************************

*******************************************************************************



PRECIPITATION 13.6 0.0 0.0 0.0 3.6 9.6 0.6 3.4 10.8 0.0 4.8 37.2

RUNOFF 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00















*******************************************************************************

*******************************************************************************

Page 10




RUNOFF 0.000 0.000 0.00




















*******************************************************************************

*******************************************************************************



PRECIPITATION 81.6 285.0 68.0 32.0 17.2 111.2 24.8 0.8 0.2 0.2 0.0 0.0

RUNOFF 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00




Page 11

Good Installation Operational HELP Model Results LATERAL DRAINAGE RECIRCULATED 0.000 0.000 0.000 0.000 0.000 0.000 FROM LAYER 3 INTO L. 1 0.000 0.000 0.000 0.000 0.000 0.000











*******************************************************************************

*******************************************************************************



RUNOFF 0.000 0.000 0.00













Page 12

Good Installation Operational HELP Model Results SOIL WATER AT START OF YEAR 1484.672 65325.578






ANNUAL WATER BUDGET BALANCE -0.0006 -0.025 0.00

*******************************************************************************

*******************************************************************************



PRECIPITATION 66.8 1.2 5.8 0.2 0.2 43.2 1.2 0.8 0.2 1.4 0.0 11.0

RUNOFF 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00














STD. DEVIATION OF DAILY 0.000 0.000 0.000 0.000 0.000 0.000

Page 13

Good Installation Operational HELP Model Results HEAD ON TOP OF LAYER 7 0.000 0.000 0.000 0.000 0.000 0.000

*******************************************************************************

*******************************************************************************



RUNOFF 0.000 0.000 0.00



















ANNUAL WATER BUDGET BALANCE -0.0001 -0.005 0.00

*******************************************************************************

*******************************************************************************



PRECIPITATION 48.4 67.2 0.0 5.0 28.0 118.4 0.0 0.4 0.0 1.4 0.0 0.4

RUNOFF 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

POTENTIAL EVAPOTRANSPIRATION 355.54 299.43 300.51 260.76 200.61 185.66

Page 14

Good Installation Operational HELP Model Results 218.62 254.64 283.27 352.51 341.10 370.61














*******************************************************************************

*******************************************************************************



RUNOFF 0.000 0.000 0.00









Page 15

Good Installation Operational HELP Model Results PERC./LEAKAGE THROUGH LAYER 7 0.000014 0.001 0.00











*******************************************************************************

*******************************************************************************



PRECIPITATION 9.6 4.4 0.4 19.6 53.8 9.8 0.0 0.8 1.6 0.2 4.6 2.6

RUNOFF 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00












Page 16





*******************************************************************************

*******************************************************************************



RUNOFF 0.000 0.000 0.00




















*******************************************************************************

*******************************************************************************



Page 17


PRECIPITATION 2.6 153.4 150.4 49.4 9.8 13.0 0.0 0.4 0.0 0.0 0.0 8.2

RUNOFF 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00















*******************************************************************************

*******************************************************************************



RUNOFF 0.000 0.000 0.00





Page 18

Good Installation Operational HELP Model Results PERC./LEAKAGE THROUGH LAYER 4 0.000846 0.037 0.00















*******************************************************************************

*******************************************************************************



PRECIPITATION 2.2 0.0 17.0 20.4 182.2 4.0 1.6 1.0 0.2 0.0 2.2 191.8

RUNOFF 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00










Page 19







*******************************************************************************

*******************************************************************************



RUNOFF 0.000 0.000 0.00




















*******************************************************************************

Page 20


*******************************************************************************



PRECIPITATION 44.0 35.0 0.6 1.2 0.0 1.6 0.6 0.0 0.0 3.2 18.8 0.0

RUNOFF 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00















*******************************************************************************

*******************************************************************************



RUNOFF 0.000 0.000 0.00

Page 21

Good Installation Operational HELP Model Results POTENTIAL EVAPOTRANSPIRATION 3429.427 150894.781



















*******************************************************************************

******************************************************************************

FINAL WATER STORAGE AT END OF YEAR 2017 ------------------------------------------------------------------------------

LAYER (CM) (VOL/VOL) ----- ------ --------- 1 72.4623 0.2898

2 0.0120 0.0401

3 0.9602 0.0320

4 0.0000 0.0000

5 0.4482 0.7470

6 0.0060 0.0100

7 0.0000 0.0000

8 0.4482 0.7470

9 14.2000 0.2840

10 58.0000 0.2320

TOTAL WATER IN LAYERS 146.537

SNOW WATER 0.000

INTERCEPTION WATER 0.000

Page 22

Good Installation Operational HELP Model Results TOTAL FINAL WATER 146.537

******************************************************************************

******************************************************************************

PEAK DAILY VALUES FOR YEARS 2007 THROUGH 2017 ------------------------------------------------------------------------------

(MM) (CU. METERS) ---------- ------------ PRECIPITATION 238.40 10489.600

RUNOFF 0.000 0.0000

DRAINAGE COLLECTED FROM LAYER 3 15.84375 697.12506

PERCOLATION/LEAKAGE THROUGH LAYER 4 0.000058 0.00253

AVERAGE HEAD ON TOP OF LAYER 4 137.665

MAXIMUM HEAD ON TOP OF LAYER 4 238.925

LOCATION OF MAXIMUM HEAD IN LAYER 3 (DISTANCE FROM DRAIN) 17.7 METERS

DRAINAGE COLLECTED FROM LAYER 6 0.00006 0.00253


AVERAGE HEAD ON TOP OF LAYER 7 0.000

MAXIMUM HEAD ON TOP OF LAYER 7 0.000

LOCATION OF MAXIMUM HEAD IN LAYER 6 (DISTANCE FROM DRAIN) 0.0 METERS


SNOW WATER 0.00 0.0000

MAXIMUM VEG. SOIL WATER (VOL/VOL) 0.6255

MINIMUM VEG. SOIL WATER (VOL/VOL) 0.0770

*** Maximum heads are computed using McEnroe's equations. ***

Reference: Maximum Saturated Depth over Landfill Liner by Bruce M. McEnroe, University of Kansas ASCE Journal of Environmental Engineering Vol. 119, No. 2, March 1993, pp. 262-270.

******************************************************************************

*******************************************************************************

AVERAGE MONTHLY VALUES (MM) FOR YEARS 2007 THROUGH 2017 -------------------------------------------------------------------------------

JAN/JUL FEB/AUG MAR/SEP APR/OCT MAY/NOV JUN/DEC ------- ------- ------- ------- ------- ------- PRECIPITATION ------------- TOTALS 49.55 65.64 43.55 14.93 27.35 36.42 7.13 1.95 1.18 1.96 5.04 23.13

STD. DEVIATIONS 80.40 89.20 69.16 15.88 53.92 42.52 14.04 2.47 3.22 4.44 8.26 57.00

Page 23

Good Installation Operational HELP Model Results RUNOFF ------ TOTALS 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

STD. DEVIATIONS 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

POTENTIAL EVAPOTRANSPIRATION ---------------------------- TOTALS 336.567 294.789 297.861 251.911 217.929 188.011 214.599 253.434 287.047 348.445 347.715 369.800

STD. DEVIATIONS 18.055 12.875 11.732 14.823 11.107 6.249 5.639 10.687 8.015 8.872 11.030 10.759

ACTUAL EVAPOTRANSPIRATION ------------------------- TOTALS 10.713 16.978 7.416 4.789 8.547 6.517 5.693 1.549 1.123 1.175 1.586 5.347

STD. DEVIATIONS 11.778 24.609 10.058 6.121 13.867 4.155 6.352 1.689 1.641 1.551 2.289 10.826

LATERAL DRAINAGE COLLECTED FROM LAYER 3 ---------------------------------------- TOTALS 23.1593 36.9890 50.9174 29.9387 14.4088 25.1378 17.5656 0.3974 0.6474 0.8383 1.0296 5.3323

STD. DEVIATIONS 42.4992 69.1840 76.8525 53.5840 20.2459 33.5187 28.8124 0.9715 1.7635 2.7495 3.2127 8.4988

LATERAL DRAINAGE RECIRCULATED FROM LAYER 3 INTO L. 1 ------------------------------------------------------ TOTALS 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000

STD. DEVIATIONS 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000

PERCOLATION/LEAKAGE THROUGH LAYER 4 ------------------------------------ TOTALS 0.0001 0.0001 0.0001 0.0001 0.0000 0.0001 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000

STD. DEVIATIONS 0.0001 0.0002 0.0002 0.0001 0.0000 0.0001 0.0001 0.0000 0.0000 0.0000 0.0000 0.0000

LATERAL DRAINAGE COLLECTED FROM LAYER 6 ---------------------------------------- TOTALS 0.0001 0.0001 0.0001 0.0001 0.0000 0.0001 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000

STD. DEVIATIONS 0.0001 0.0002 0.0002 0.0001 0.0000 0.0001 0.0001 0.0000 0.0000 0.0000 0.0000 0.0000

LATERAL DRAINAGE RECIRCULATED FROM LAYER 6 INTO L. 1 ------------------------------------------------------ TOTALS 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000

STD. DEVIATIONS 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000


STD. DEVIATIONS 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000


Page 24


STD. DEVIATIONS 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000

------------------------------------------------------------------------------- AVERAGES OF MONTHLY AVERAGED DAILY HEADS (CM) -------------------------------------------------------------------------------

DAILY AVERAGE HEAD ON TOP OF LAYER 4 ------------------------------------- AVERAGES 0.6491 1.1439 1.4272 0.8671 0.4039 0.7281 0.4923 0.0111 0.0188 0.0235 0.0298 0.1495

STD. DEVIATIONS 1.1912 2.1478 2.1541 1.5520 0.5675 0.9708 0.8076 0.0272 0.0511 0.0771 0.0930 0.2382

DAILY AVERAGE HEAD ON TOP OF LAYER 7 ------------------------------------- AVERAGES 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000

STD. DEVIATIONS 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000

*******************************************************************************

*******************************************************************************

AVERAGE ANNUAL TOTALS & (STD. DEVIATIONS) FOR YEARS 2007 THROUGH 2017 -------------------------------------------------------------------------------

MM CU. METERS PERCENT -------------------- ----------- --------- PRECIPITATION 277.80 ( 187.475) 12223.2 100.00

RUNOFF 0.000 ( 0.0000) 0.00 0.000

POTENTIAL EVAPOTRANSPIRATION 3408.108 ( 52.4596) 149956.77

ACTUAL EVAPOTRANSPIRATION 71.433 ( 43.3038) 3143.06 25.714

LATERAL DRAINAGE COLLECTED 206.36140 (141.50063) 9079.901 74.28415 FROM LAYER 3

DRAINAGE RECIRCULATED 0.00000 ( 0.00000) 0.000 0.00000 FROM LAYER 3 INTO L. 1

PERCOLATION/LEAKAGE THROUGH 0.00058 ( 0.00039) 0.026 0.00021 LAYER 4

AVERAGE HEAD ON TOP 4.954 ( 3.432) OF LAYER 4

LATERAL DRAINAGE COLLECTED 0.00057 ( 0.00039) 0.025 0.00020 FROM LAYER 6

DRAINAGE RECIRCULATED 0.00000 ( 0.00000) 0.000 0.00000 FROM LAYER 6 INTO L. 1


AVERAGE HEAD ON TOP 0.000 ( 0.000) OF LAYER 7


CHANGE IN WATER STORAGE 0.005 ( 2.3623) 0.21 0.002

******************************************************************************* *******************************************************************************

Page 25



: Water Balance Model


Shire of Ashburton

Leachate Evaporation Pond Design

Input Values =

Evaporative Zone Depth =

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

90th Percentile 180.1 7.7 24.5 4.3 236.7 76.8 7.4 1.3 1.5 0 0 0.3 540.6 mm

0.1801 0.0077 0.0245 0.0043 0.2367 0.0768 0.0074 0.0013 0.0015 0 0 0.0003 0.5406 m

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

Onslow 350 300 300 300 175 125 125 175 250 300 350 400 3150 mm

0.35 0.3 0.3 0.3 0.175 0.125 0.125 0.175 0.25 0.3 0.35 0.4 3.15 m

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total (m3) Total Evap (m2) Rainfall (m2)

Leachate Generation 1,019 1,628 2,240 1,317 634 1,106 773 17 28 37 45 235 9,080 23,310.00 4,843.78

Evaporation Pond Sizes L W h Evaporation Pond L W h

Catchment Area 80 56 1.5 1: 3 Catchment Area 80 56 1.5 1: 3

Evaporation Area 74 50 74 50

Evaporation Depth 1 m

Runoff Coefficient 1 a 47 a 47

Evap Coefficient 0.8 b 71 b 71

Total Capacity 11,685 m3

Total Operational Capacity 9,507 m3 Catchment Area 4,480 m2 4,480 m2

Factor of Safety 2.63 Evaporation Area 3,700 m2 3,700 m2

Total Pond Volume 5,843 m3 5,843 m3

Operational Pond Volume 4,754 m3 4,754 m3

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

Year 1 561 481 1,165 745 2,464 3,518 3,617 2,610 1,172 0 0 0

Year 2 561 481 1,165 745 2,464 3,518 3,617 2,610 1,172 0 0 0

Year 3 561 481 1,165 745 2,464 3,518 3,617 2,610 1,172 0 0 0

Year 4 561 481 1,165 745 2,464 3,518 3,617 2,610 1,172 0 0 0

Year 5 561 481 1,165 745 2,464 3,518 3,617 2,610 1,172 0 0 0

Year 6 561 481 1,165 745 2,464 3,518 3,617 2,610 1,172 0 0 0

Year 7 561 481 1,165 745 2,464 3,518 3,617 2,610 1,172 0 0 0

Year 8 561 481 1,165 745 2,464 3,518 3,617 2,610 1,172 0 0 0

Year 9 561 481 1,165 745 2,464 3,518 3,617 2,610 1,172 0 0 0

Year 10 561 481 1,165 745 2,464 3,518 3,617 2,610 1,172 0 0 0

To be completed

2.5cm

Above Capacity - Potential BreachWithin Operational Capacity

Evaporation Area

Catchment Area

Evaporation Area

Pond Side Slope

Remaining Volumes Post Evaporation

Pond Side Slope

Cu

mu

lati

ve R

esi

du

al V

olu

me

s

Total Pond Volume

Annual

Annual

Operational Pond Volume

TW18004


Shire of Ashburton

Leachate Evaporation Pond Design

Input Values =

Evaporative Zone Depth =

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

Highest within 10 years 84.8 284.2 68.8 32 16.8 90 46.4 0.8 0.2 0.2 0 0 624.2 mm

0.0848 0.2842 0.0688 0.032 0.0168 0.09 0.0464 0.0008 0.0002 0.0002 0 0 0.6242 m

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

Onslow 350 300 300 300 175 125 125 175 250 300 350 400 3150 mm

0.35 0.3 0.3 0.3 0.175 0.125 0.125 0.175 0.25 0.3 0.35 0.4 3.15 m

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total (m3) Total Evap (m2) Rainfall (m2)

Leachate Generation 1,019 1,628 2,240 1,317 634 1,106 773 17 28 37 45 235 9,080 23,310.00 5,592.83

Evaporation Pond Sizes L W h Evaporation Pond L W h

Catchment Area 80 56 1.5 1: 3 Catchment Area 80 56 1.5 1: 3

Evaporation Area 74 50 74 50

Evaporation Depth 1 m

Runoff Coefficient 1 a 47 a 47

Evap Coefficient 0.8 b 71 b 71

Total Capacity 11,685 m3

Total Operational Capacity 9,507 m3 Catchment Area 4,480 m2 4,480 m2

Factor of Safety 2.03 Evaporation Area 3,700 m2 3,700 m2

Total Pond Volume 5,843 m3 5,843 m3

Operational Pond Volume 4,754 m3 4,754 m3

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

Year 1 0 2,398 3,479 3,307 3,055 4,228 4,676 3,665 2,215 478 0 0

Year 2 0 2,398 3,479 3,307 3,055 4,228 4,676 3,665 2,215 478 0 0

Year 3 0 2,398 3,479 3,307 3,055 4,228 4,676 3,665 2,215 478 0 0

Year 4 0 2,398 3,479 3,307 3,055 4,228 4,676 3,665 2,215 478 0 0

Year 5 0 2,398 3,479 3,307 3,055 4,228 4,676 3,665 2,215 478 0 0

Year 6 0 2,398 3,479 3,307 3,055 4,228 4,676 3,665 2,215 478 0 0

Year 7 0 2,398 3,479 3,307 3,055 4,228 4,676 3,665 2,215 478 0 0

Year 8 0 2,398 3,479 3,307 3,055 4,228 4,676 3,665 2,215 478 0 0

Year 9 0 2,398 3,479 3,307 3,055 4,228 4,676 3,665 2,215 478 0 0

Year 10 0 2,398 3,479 3,307 3,055 4,228 4,676 3,665 2,215 478 0 0

Pond Side Slope

Cu

mu

lati

ve R

esi

du

al V

olu

me

s

Total Pond Volume

Annual

Annual

Operational Pond Volume

To be completed

2.5cm

Above Capacity - Potential BreachWithin Operational Capacity

Evaporation Area

Catchment Area

Evaporation Area

Pond Side Slope


TW18004

Shire of Ashburton

Pilbara Regional Waste Management FacilityWater Balance Model - Green Waste Drainage Pond September 2018

Rainfall Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual Rainfall (m2)

90th Percentile 180.10 7.70 24.50 4.30 236.70 76.80 7.40 1.30 1.50 0.00 0.00 0.30 541 mm 708

0.1801 0.0077 0.0245 0.0043 0.2367 0.0768 0.0074 0.0013 0.0015 0.0000 0.0000 0.0003 0.5406 m

Pan Evaporation Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual Total Evap (m2)

Onslow Evaporation 350.0 300.0 300.0 300.0 175.0 125.0 125.0 175.0 250.0 300.0 350.0 400.0 3,150 mm 2,331

0.3500 0.3000 0.3000 0.3000 0.1750 0.1250 0.1250 0.1750 0.2500 0.3000 0.3500 0.4000 3.15 m

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total (m3)

Inputs - From Green Waste Pad 135 6 18 3 178 58 6 1 1 0 0 0 405 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Outputs 0 0 0 0 0 0 0 0 0 0 0 0 - Year 1 2019 164 2 0 0 384 468 409 309 164 0 0 0

Number of weeks each month 4.4 4.0 4.4 4.3 4.4 4.3 4.4 4.4 4.3 4.4 4.3 4.4 52 Year 2 2020 164 2 0 0 384 468 409 309 164 0 0 0

Year 3 2021 164 2 0 0 384 468 409 309 164 0 0 0

Key Parameters Year 4 2022 164 2 0 0 384 468 409 309 164 0 0 0

Runoff Coefficient (Drainage Pond) 1 Year 5 2023 164 2 0 0 384 468 409 309 164 0 0 0

Evaporation Coefficient 0.8

Evaporation Area: Distance from top of pond to liquor level 0.42 m

Processing Area Surface Area 1,500 m2

Runoff Coefficient (Processing Area) 0.5

Leachate Holding Pond

L W h

Catchment Area 64 19 1.4 1: 6

a 3

b 46

Catchment Area 1,310 m2

Evaporation Area 740 m2 *Assuming pond is at 75% capacity from freeboard

Max. Operational Pond Volume 481 m3 *Assuming 0.4m freeboard

Total Capacity 962 m3

72hr, 1-in-10 year storm event 307 m3

NOTES:

During significant rainfall events, any overflow from the green waste drainage pond will be pumped into the Site's leachate pond systemIt is assumed that only a fraction of the Green Waste Processing Area will be used during initial operations. The pond has been designed to include the rainfall catchment from 1,500m2 of the Green Waste Processing Area. The design of pond should be reviewed if operations increase over more surface area.

Pond Side Slope

Leachate Holding Pond


Date

Cumulative

Residual

Volumes

Above Operational Capacity - Potential Breach

Within Operational Capacity

Above Capacity - Breach

TW18004

Documents

Leachate Management Plan - epa.wa.gov.auepa.wa.gov.au/sites/default/files/Referral_Documentation/14 - Leacha… · 1 Introduction Talis Consultants Pty Ltd (Talis) was commissioned