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Reference Document - Dewatering Management Plan (For Stamping) MCU25/0053 & OPW25/0074
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NOOSA COUNCIL
REFERENCE DOCUMENT
MCU25/0053 & OPW25/0074 21
NOVEMBER 2025
ADG Consulting Pty Ltd All Correspondence
ACN: 630 555 225 PO Box 6405
ABN: 98 630 555 225 Yatala DC QLD 4207
P 07 3801 1564
E [email protected]
W adgconsulting.com.au
Dewatering Management Plan
Proposed Residential Development:
Lot 0 on BUP10936, 7 Noosa Parade, Noosa Heads, Queensland.
May 2025
Prepared for:
Seymour Group
Acid Sulfate Soil Assessment On‐site Wastewater Management Contaminated Land Assessment & Remediation
Dewatering Management Environmental Management Plans Surface & Groundwater Investigation & Monitoring
Document Set ID: 23735664
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Report details
Project ref: ADG1777.25
ADG Project Manager: Michael Campbell
Report title: Dewatering Management Plan
Proposed Residential Development:
Lot 0 on BUP10936, 7 Noosa Parade, Noosa Heads, Queensland
Version: Rev0
Author: Lilli O’Sullivan
Reviewer: Michael Campbell
Client: Seymour Group
Client contact: Belinda Amble
Distribution date: 1 May 2025
Distributed to: Seymour Leisure Trust
Copies: 1 PDF
ADG Consulting Pty Ltd
Lilli O’Sullivan Michael Campbell BEnvSc, BSc[Hons],
BEnvSc, DipProjMgt, DipOHS, DipBusMgt, DipBus(Quality Auditing)
Environmental Scientist MEIANZ, MALGA, MASSI
Director & Principal Environmental Scientist
Date: 1 May 2025
This document and all its content is copyright. Apart from fair dealing for the purposes of study, research, criticism
and/or review as permitted under the Copyright Act 1968, no part of the content may be reproduced, reused or
redistributed without the prior written permission of ADG Consulting Pty Ltd.
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Table of Contents
1 INTRODUCTION 1
1.1 PROPOSED DEVELOPMENT 1
1.2 RELEVANT GUIDELINES 1
1.3 GENERAL ENVIRONMENTAL DUTY 2
1.4 DMP OBJECTIVES 2
1.5 SCOPE OF WORK 2
2 SITE CHARACTERISTICS 3
2.1 PROPERTY DESCRIPTION 3
2.2 SURROUNDING ENVIRONMENT 3
2.3 TOPOGRAPHY 3
2.4 GEOLOGY & SOILS 3
2.5 HYDROGEOLOGY 3
3 PREVIOUS INVESTIGATIONS 4
3.1 PTG CONSULTING 2025 4
3.1.1 SOILS 4
3.1.2 GROUNDWATER 4
3.2 GROUNDWATER QUALITY 5
4 WATER QUALITY OBJECTIVES 6
4.1 RECEIVING ENVIRONMENT 6
4.2 DEVELOPMENT OF WATER QUALITY OBJECTIVES 6
4.3 PROPOSED WATER QUALITY OBJECTIVES 7
5 DEWATERING METHODOLOGY 10
5.1 BASEMENT EXCAVATION AND SHORING 10
5.2 GROUNDWATER EXTRACTION 10
5.3 EXTRACTION/DISCHARGE RATES AND VOLUME 10
5.3.1 DEWATERING EXTRACTION CALCULATION BASED ON SUBSURFACE SOIL PROFILE 10
5.4 DEWATERING DURATION 11
5.5 GROUNDWATER DRAWDOWN 11
5.6 GROUNDWATER TREATMENT 12
5.7 NOMINATED HOLD POINTS 12
6 WATER QUALITY MANAGEMENT 13
6.1 RESPONSIBILITY 13
6.2 OPERATIONAL POLICY 13
6.3 PERFORMANCE CRITERIA 13
6.4 IMPLEMENTATION STRATEGY 13
6.4.1 GROUNDWATER TREATMENT SYSTEMS 13
6.4.2 DEWATERING STRATEGY 14
6.4.3 INITIAL PUMP‐OUT 14
6.5 MONITORING 14
6.5.1 VISUAL MONITORING 14
6.5.2 WATER QUALITY MONITORING 14
6.5.3 MONITORING RESPONSIBILITIES 15
6.6 MAINTENANCE 16
6.7 REPORTING 16
6.8 CONTINGENCIES 17
7 NOISE & ODOUR MANAGEMENT 18
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7.1 RESPONSIBILITY 18
7.2 OPERATIONAL POLICY 18
7.3 PERFORMANCE CRITERIA 18
7.4 IMPLEMENTATION STRATEGY 18
7.4.1 NOISE 18
7.4.2 ODOUR 18
7.5 MONITORING 18
7.6 REPORTING 19
7.7 CONTINGENCIES 19
8 LIMITATIONS 20
9 REFERENCES 21
APPENDIX A: FIGURES
APPENDIX B: LICENCED GROUNDWATER BORE SEARCH RESULTS
APPENDIX C: DRAWINGS
APPENDIX D: CONE OF DEPRESSION CALCULATIONS
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1 Introduction
ADG Consulting Pty Ltd (ADG) was engaged by Seymour Group to prepare a Dewatering Management
Plan (DMP) for the proposed residential apartment development within property described as Lot 0 on
BUP10936, 7 Noosa Parade, Noosa Heads, Queensland.
1.1 Proposed development
It is understood the proposed development will comprise a two‐storey building over a single‐level in‐
ground basement, extending across the 1,120 m2 site.
Based on information provided by Seymour Group, existing ground levels across the proposed basement
footprint are approximately RL 2.1 m Australian Height Datum (AHD). Excavations to facilitate the
basement construction are proposed to extend to an approximate depth of 2.8 m below existing ground
level (bgl), corresponding to an approximate elevation of RL ‐1.1 mAHD (i.e. finished basement floor level
of RL ‐0.7 mAHD; allowing for 400 mm raft slab and blinding layer). Localised deeper excavations may be
required to facilitate other structural elements (i.e. lift overrun pit, pile caps and footings), where
required.
During a geotechnical and acid sulfate soil investigation on the site in January 2025, no groundwater was
recorded in the drilling of boreholes to the depth of 4.5 mgbl (PTG Consulting, 2025). PTG noted that
groundwater levels are expected to fluctuate in response to variations in rainfall and are likely to rise
close to the ground surface during periods of heavy or prolonged rainfall. No further recent data has been
supplied for review in preparing this DMP, however based on ADG’s experience on nearby sites in the
locality in recent years, it is anticipated that groundwater should be expected at or around 0.5 m AHD +/‐
0.5 m, depending on tidal and seasonal rainfall conditions. Dewatering will therefore be necessary to
allow the basement and other structural elements to be constructed in dry conditions.
1.2 Relevant guidelines
The DMP was prepared with reference to the following documents:
Australian and New Zealand Guidelines for Fresh and Marine Water Quality 2018. Australian and
New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia
(ANZG, 2018), which supersedes Australian and New Zealand Guidelines for Fresh and Marine Water
Quality, Australian and New Zealand Environment and Conservation Council and Agriculture and
Resource Management Council of Australia and New Zealand (ANZECC/ARMCANZ). 2000.
Environmental Protection (Water & Wetland Biodiversity) Policy 2019. Queensland Government.
2019.
Guidelines for Managing Risks in Recreational Water. Australian Government, National Health and
Medical Research Council (NHMRC). 2008.
Monitoring and Sampling Manual 2018, Version 2 June 2018. Department of Environment and
Science (DES). 2018.
Noosa River environmental values and water quality objectives. Department of Environment and
Science (DES). 2022.
National Environment Protection (Assessment of Site Contamination) Measure 1999, (as amended
May 2013). National Environment Protection Council (NEPC). 2013.
Queensland Water Quality Guidelines 2009, Version 3. The Department of Environment and
Heritage Protection (DEHP). 2013.
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1.3 General environmental duty
The Environmental Protection Act 1994 describes that all persons in Queensland have a “General
Environmental Duty” and that “a person must not carry out an activity that causes, or is likely to cause
environmental harm unless the person takes all reasonable and practicable measures to prevent or
minimise the harm”.
The Act requires that appropriate action be taken to report that environmental harm is occurring or has
the potential to occur, unless the harm is authorised under an environmental protection policy, an
environmental management program, a development approval, or an environmental protection order.
This is known as the “Duty to Notify”. Failure to fulfil this duty is an offence and may result in prosecution.
1.4 DMP objectives
The objectives of the DMP are to:
1. Describe the dewatering methodology, groundwater treatment, monitoring and reporting
procedures to be employed at the site during dewatering activities.
2. Provide effective management procedures to prevent environmental harm resulting from the
discharge of extracted groundwater from the site.
1.5 Scope of work
To achieve the investigation objectives, the following scope of work was undertaken:
A desktop study including:
1. Review of the development proposal and proposed shoring/dewatering designs.
2. Review of geology and soil maps for the area.
3. Search of groundwater bores licensed by the Queensland Government within a 200 m radius of
the site.
4. Review of relevant existing reports and groundwater data from the local area.
5. Review of current aerial photographs of the site and surrounds.
The preparation of this Dewatering Management Plan suitable for submission to Noosa Shire
Council (NSC), if required.
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2 Site characteristics
2.1 Property description
The site comprises a single parcel of land described as Lot 0 on BUP10936, situated at 7 Noosa Parade,
Noosa Heads, Queensland. The site is rectangular in shape with an area of 1,120m2 and is shown in Figure
1, Appendix A.
2.2 Surrounding environment
The surrounding environment and land use is described briefly in Table 1.
Table 1 Surrounding land use and environment
Direction Environment
North Noosa Parade, then residential properties, then Noosa River
Noosa Park, then Noosa River, then Noosa Parade, then high‐density properties
East
(hotels).
South Noosa River, then residential properties, then Witta Circuit.
West Residential property, then Witta Circle, then residential/holiday properties.
2.3 Topography
The site is considered to be relatively level based on its existing use as a residential property.
2.4 Geology & soils
The surface geology at the site is mapped as being Anthropocene aged man‐made deposits (‘Qhh‐QLD’)
comprising gravel, sand and silt; man‐made deposits generally associated with land‐fill or mining (tailings,
dumps and rehabilitated areas. The dominant rock type is identified as stratified volcanic and
metamorphic as referenced through detailed surface geology (accessed via Queensland Globe online, 17
April 2025).
The site is mapped within the Atlas of Australian Soils (‘Ca10’, accessed via Queensland Globe online, 17
April 2025) as Podzols soils described as well‐drained, bleached A2 horizon and brown or reddish brown
B horizon. These soils are generally described as undulating to rolling roughly parallel old dune system.
The Acid Sulfate Soils (ASS) 1:100,000 Tweed Heads to Teewah Overlay map categorises the site as ‘SDL’
or ‘Acid Sulfate on Disturbed Land’, indicating that the site is likely to contain acid sulfate soils (and
potential exists that partial or full treatment may have been undertaken), however the type and depth
to ASS is not defined (accessed via Queensland Globe online, 17 April 2025).
2.5 Hydrogeology
A search of groundwater bores licensed by the Queensland Government was conducted on 17 April 2025
via the Queensland Globe online database. The search identified no (0) licensed bores within a 200 m
radius of the site and is shown in Appendix B.
Based on the local geology and topography, and the site’s proximity to the Noosa River, the inferred
groundwater flow is to the south toward the Noosa River. Groundwater beneath the site is expected to
be hydraulically connected to the Noosa River, therefore saline groundwater conditions are anticipated,
and additional saltwater intrusion is likely to occur during dewatering. Any changes to the salinity levels
in the groundwater are anticipated to rapidly return to existing conditions following the completion of
dewatering and subsequent rainfall/alluvial percolation.
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3 Previous investigations
This DMP is based on site specific information sourced from the following documentation provided to
ADG by Seymour Group:
PTG Consulting. February 2025. Geotechnical Investigation Report – Proposed Residential
Development 7 Noosa Parade, Noosa Heads. PTG/01608 – 001 – Rev 0.
PTG Consulting. April 2025. Acid Sulfate Soil Investigation Management Plan – Proposed Residential
Development 7 Noosa Parade, Noosa Heads. PTG/01608 – 002 – Rev 0.
SCG Consulting. May 2025. Operational Works for Residential Development Lot CP on BUP 10936
No. 7 Noosa Pde, Noosa Heads. Rev issued 1 May 2025. (see Appendix C).
Bureau Proberts. April 2025. Drawing. Proposed Residence 7 Noosa Parade. 24048 – AR 00.01 –
Rev 4.
A brief discussion of relevant soil and groundwater conditions is provided below.
3.1 PTG Consulting 2025
A Geotechnical and Acid Sulfate Soil (ASS) Investigation was undertaken on the site by PTG Consulting in
January 2025 (report dated February 2025). The following sections summarise the relevant information
from the report provided.
3.1.1 Soils
During the Geotechnical and ASS investigation four (4) boreholes (BH1 to BH4) were drilled to depths of
4.5 m below ground level (bgl) using solid flight auger with a specialised 4WD truck‐mounted drill rig. The
sub‐surface soil profile comprised a silty sand/ sand to the termination depth of 4.5 mbgl. The sands
were described as generally medium dense to dense, with some loose material encountered near the
surface.
A total of seventy‐two (72) soil samples were recovered from boreholes (BH1 to BH4) at 0.25 m intervals
from between 0.0 m and 4.5 m in depth. Based on field screening results, a total of eighteen (18) samples
were selected for laboratory analysis by the Chromium Reducible Sulfur suite (CRS). The analysed samples
reported the presence of low to high levels of potential acid sulfate soils (PASS) throughout the soil profile
with titratable actual acidity (TAA) concentrations ranging from <10 to 128 moles H+/tonne (9 of 18
samples reporting above the action criteria of 18 moles H+/tonne). Nine (9) samples reported oxidisable
sulfur concentrations ranging from 0.066 to 0.194 %S which were at or above the relevant action criterion
of 0.03 %S, indicating the presence of potential acid sulfate soils (PASS) within the soil profile to
approximately 4.5 m (extent of investigation by PTG Consulting).
PTG Consulting estimated, approximately 800 tonnes of soil will be disturbed below RL 5 m AHD. With
the highest recorded net acidity value of 128 mol H+/t, a ‘Very High Level of Treatment’ is required. The
results indicate soils contain high levels of existing and potential acidity and will therefore require
management of actual acid sulfate soils. A maximum liming rate of 10 kg CaCO3/m3 was calculated for
the site.
It is noted that the ASS investigation did not provide assessment of deeper soils (>4.5 mbgl) or cone of
depression that will be created during dewatering. Given ADG’s previous experience with ASS and
dewatering operations in the local area, ASS conditions are likely to become more significant with
increasing depth and rewetting of the soil structure in the cone of depression following commencement
of dewatering.
3.1.2 Groundwater
During the geotechnical and acid sulfate soil investigation, no groundwater was reported as being
encountered during the drilling of the boreholes (PTG Consulting, 2025). PTG Consulting notes, that
groundwater levels can be perched and fluctuate seasonally and during heavy rainfall events. Due to the
site sites close proximity to the tidal Noosa River and the permeable natural of the soils encountered,
increases the likelihood of groundwater fluctuations. In addition, ADGs recent previous experience in the
locality has generally identified standing groundwater at or around RL 0.5 to 1.0 mAHD, and given the
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sandy subsurface profile and proximity to the tidal canal network associated with Noosa Inlet these
relative groundwater levels should be expected, with higher levels during or following periods of intense
or extended rainfall.
3.2 Groundwater quality
No site specific groundwater investigation was undertaken as part of the Geotechnical and ASS
Investigations undertaken by PTG Consulting. However, ADG is of the opinion that localised monitoring
well data can often be misleading and does not always accurately represent the properties of the
groundwater that will be extracted and treated from the entire site and local surrounds during
dewatering. Therefore, based on numerous groundwater investigations and dewatering monitoring
projects that have been undertaken by ADG throughout the Noosa Coast and nearby sites in recent years.
Our understanding of the groundwater quality in the region is provided below:
Groundwater is generally mildly acidic to neutral, with pH levels ranging from approximately 5.5 to
6.5 and electrical conductivity ranging from brackish to saline between 2,000 µS/cm to
48,000 µS/cm. Groundwater pH has the potential to reduce (become more acidic) following
oxidisation of PASS as dewatering progresses, particularly if re‐wetting of the soils occurs.
Dissolved oxygen levels in static groundwater typically range from approximately 35 – 40 %
saturation.
The groundwater associated with indurated sand strata is moderately to highly turbid as a result of
staining and organic content.
Concentrations of dissolved metals are typically below the available marine water trigger values
(MWTV’s) in ANZG (2018) which supersedes ANZECC/ARMCANZ (2000) for the receiving waters,
however elevated levels of aluminium and particularly iron are expected in the untreated
groundwater and have the potential to increase following oxidisation of PASS as dewatering
progresses or as a result of existing acidic groundwater conditions.
Given the location and previous use of the site, groundwater impacts resulting from site
contamination are not anticipated.
A groundwater investigation will be undertaken at the commencement of dewatering as described in
Section 6.5.2 of this report. This assessment will be representative of the groundwater being extracted
and treated from the entire site, as opposed to localised monitoring well data which is often misleading.
Based on previous experience with dewatering in the area, ADG expects the groundwater to require
treatment to increase pH and dissolved oxygen levels, as well as reduce turbidity, suspended sediments
and dissolved metal concentrations prior to being discharged to the stormwater system.
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4 Water quality objectives
4.1 Receiving environment
It is proposed to discharge extracted groundwater directly over the revetment wall into the adjacent
canal network (Noosa River) immediately south of the site (to be confirmed upon commissioning to site).
The waterway in this location is mapped as a tidal canal, harbour or marina (DES, 2022). The receiving
environment is connected to the Noosa River which ultimately connects to the Pacific Ocean. The
following section establishes water quality objectives (WQOs) to ensure that the environmental values
of the receiving waters are protected and maintained.
4.2 Development of water quality objectives
WQOs have been developed to support and protect the designated environmental values (EVs) for the
receiving environment. The WQOs are based on a moderately disturbed level of protection for estuarine
(marine) waters in tidal canals, constructed estuaries, marinas and boat harbours. The WQOs have been
developed with reference to the following guideline documents:
Australian and New Zealand Guidelines for Fresh and Marine Water Quality 2018 (ANZG, 2018).
Australian and New Zealand Governments and Australian state and territory governments, Canberra
ACT, Australia, which supersedes Australian and New Zealand Guidelines for Fresh and Marine
Water Quality, Australian and New Zealand Environment and Conservation Council and Agriculture
and Resource Management Council of Australia and New Zealand (ANZECC/ARMCANZ). 2000.
Environmental Protection (Water & Wetland Biodiversity) Policy 2019. Queensland Government.
2019.
Guidelines for Managing Risks in Recreational Water. Australian Government, National Health and
Medical Research Council (NHMRC). 2008.
Noosa River environmental values and water quality objectives. Department of Environment and
Science (DES). 2022.
Queensland Water Quality Guidelines, Version 3, September 2009. 2013. DEHP.
The Australian and New Zealand Guidelines for Fresh and Marine Water Quality by the Australian and
New Zealand Environment and Conservation Council and Agriculture and Resource Management Council
of Australia and New Zealand (ANZECC/ARMCANZ, 2000), has undergone review, with the publication of
the 2018 version. The revised Australian and New Zealand Guidelines for Fresh and Marine Water Quality
2018 is a joint initiative between the Australian and New Zealand Governments and Australian state and
territory governments (ANZG, 2018) and supersedes the ANZECC/ARMCANZ 2000 publication. Where
ANZECC/ARMCANZ (2000) is referenced, the relevant sections are still relevant and consistent with the
updated ANZG 2018 publication, as referenced in the ANZG 2018 publication.
The Queensland Water Quality Guidelines 2009 (DEHP, 2013) was made pursuant to the provisions of the
Environmental Protection (Water) Policy 1999 (the EPP(Water)), which is a subordinate legislation under
the Environmental Protection Act 1994 and was developed as the State response to the
ANZECC/ARMCANZ (2000) Guidelines. This has been further superseded by EPP (Water and Wetland
Biodiversity) 2019 which provides a framework for:
Identifying environmental values for Queensland waters, and deciding the water quality objectives
to protect or enhance those environmental values; and
Including the identified environmental values and water quality objectives under Schedule 1 of the
EPP (Water).
WQOs are long term goals for surface water quality management. They are indicators established for
receiving waters to support and protect the designated Environmental Values (EVs) for those waters. DES
(2022) describes that for slightly to moderately disturbed waters, the guideline values should be
compared with the median of values at a test site, whilst ANZG (2018) stresses that the aquatic ecosystem
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guideline values are triggers to further action, are inherently conservative, and that the response to non‐
compliance should match the magnitude and impacts (if any) of the exceedance.
Section 5 (Guidelines for recreational water quality and aesthetics) of the previous ANZECC/ARMCANZ
(2000) Guidelines (per section 5.2 thereof) was superseded by the Guidelines for Managing Risks in
Recreational Water in 2008 (NHMRC, 2008). Therefore, a reference to the ANZECC/ARMCANZ
(2000)/ANZG (2018) Guidelines is by association and extension a reference to the current 2008 NHMRC
Guidelines. The 2008 NHMRC Guidelines contain no criteria for aluminium, and only includes an aesthetic
criterion for iron – noting this is an aesthetic criterion derived from the Australian Drinking Water
Guidelines on the basis of ingesting 2L of the recreational water solution per day. ANZECC/ARMCANZ
(2000) Section 5.2.3.3, notes that as a general guideline, under Toxic Chemicals, ‘Higher concentrations
of toxicants may be tolerated occasionally if it assumed that no person will ingest more than a maximum
of 100 mL water during a normal swimming session (NHMRC 1990) compared with 2L/d for potable
water’, and Section 3.1.1.3, under Risk based approach of the guidelines, ‘The guideline trigger values are
based on bioavailable concentrations, and hence are relatively conservative when compared with total
concentrations in the field, so the use of the decision frameworks will increase guideline concentrations
in most cases’. Therefore, any chemical toxicant trigger values would require reassessment and likely
increase upwards of any ANZECC/ARMCANZ (2000)/ANZG (2018) Guideline trigger values due to the
slightly to moderately disturbed nature (and thereby reduced sensitivity) of the receiving waters.
Regardless of the WQOs adopted in this DMP, the General Environmental Duty set out in the EP Act is
paramount, which requires that “a person must not carry out an activity that causes or is likely to cause
environmental harm unless the person takes all reasonable and practicable measures to prevent or
minimise the harm”.
4.3 Proposed water quality objectives
The proposed water quality objectives that have been developed for the discharge of extracted
groundwater from the site are provided in the Tables below. All water discharged from the site must
comply with the discharge criteria provided in Table 2. Additionally, the receiving water quality within a
20m radius of the discharge point (the receiving waters mixing zone) shall comply with the receiving
water criteria provided in Table 3. Receiving waters data will be assessed against background monitoring
data if non‐compliant results are obtained at the receiving waters monitoring location.
Table 2 Discharge criteria
Parameter Criteria
Physico‐chemical
pH (pH units) 6.5 – 8.51,2
Dissolved oxygen (% saturation) >802
Suspended solids (mg/L) <501,2
Turbidity (NTU) <502
Litter/visible plumes None visible at the point of discharge or in a waterway
Total metals (µg/L)
Aluminium 2003
Iron 3003
Table notes:
1. QWQG 2009 (2013) Refer to Table 8.2.1. Summary of design objectives for management of stormwater quality and flow – construction
phase of development in Queensland.
2. Typical discharge criteria recognised throughout QLD.
3. SCC (2008). Water release criteria as specified in the SCC Manual for Erosion and Sediment Control, Chapter 6.
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Table 3 Receiving waters criteria
Parameter Criteria
Physico‐chemical
pH (pH units) 7.8 – 8.31
Dissolved oxygen (% saturation) 85 – 1051
Suspended solids (mg/L) ≤141
Turbidity (NTU) ≤61
Dissolved metals (µg/L)
Aluminium No relevant ANZG criterion available
Arsenic No relevant ANZG criterion available*
Cadmium 5.52
Chromium 4.42
Copper 1.32
Iron No relevant ANZG criterion available
Lead 4.42
Nickel 702
Zinc 82
Mercury 0.42
Total metals (µg/L)
Aluminium No ANZG criteria / 2003
Iron No ANZG criteria / 3003
Table notes:
1. DES (2022). Noosa River environmental values and water quality objectives (moderately disturbed – Noosa River – canals and marinas).
2. ANZG (2018) – Marine water trigger values for 95% species protection (Supersedes ANZECC/ARMCANZ (2000)).
3. Criteria subject to expected condition in Development Application (DA) notice by Noosa Shire Council.
Although ADG has not been provided a copy of any DA notice or conditions for the proposed development
(not yet available at the time of writing), based on previous dewatering projects in the Noosa Coast
Region it is expected that total iron and aluminium concentrations as listed in Error! Reference source
not found. (above) are likely to be conditioned by Noosa Shire Council for compliance. It should be noted
that these concentrations are considered to be onerous with respect to the risk‐based (worst‐case)
bioavailable trigger value criteria contained in ANZG 2018 & ANZECC/ARMCANZ (2000) for marine water
(moderately disturbed) 95% species protection, and are likely to be difficult to achieve given the
groundwater conditions encountered in the locality on previous dewatering projects on the Noosa Coast.
Prior to discharge to the stormwater system or any waterway, discharges are to be tested to meet the
requirements of the ANZG 2018 & ANZECC/ARMCANZ (2000) Guidelines for Fresh and Marine Water
Quality. There is currently no chemical toxicant trigger value criteria available for total or dissolved (i.e.
bioavailable) concentrations of aluminium or iron for marine or estuarine waters under the Australian
and New Zealand Guidelines for Fresh and Marine Water Quality Guidelines (ANZG 2018 &
ANZECC/ARMCANZ 2000 – i.e. ANZECC Guidelines) or the Guidelines for Managing Risks in Recreational
Waters (NHMRC 2008), with regards to managing environmental impacts to the waterway.
In addition, Section 5 (Guidelines for recreational water quality and aesthetics) of the ANZECC/ARMCANZ
(2000) Guidelines (per section 5.2 thereof) was superseded by the Guidelines for Managing Risks in
Recreational Water in 2008 (NHMRC, 2008). Therefore, a reference to the ANZECC/ARMCANZ (2000)
Guidelines is by association and extension a reference to the current 2008 NHMRC Guidelines. The 2008
NHMRC Guidelines contain no criteria for aluminium, and only includes an aesthetic criterion for iron –
noting this is an aesthetic criterion derived from the Australian Drinking Water Guidelines on the basis of
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ingesting 2L of the recreational water solution per day. ANZECC/ARMCANZ (2000) Section 5.2.3.3, notes
that as a general guideline, under Toxic Chemicals, ‘Higher concentrations of toxicants may be tolerated
occasionally if it assumed that no person will ingest more than a maximum of 100 mL water during a
normal swimming session (NHMRC 1990) compared with 2L/d for potable water’, and Section 3.1.1.3,
under Risk based approach of the guidelines, ‘The guideline trigger values are based on bioavailable
concentrations, and hence are relatively conservative when compared with total concentrations in the
field, so the use of the decision frameworks will increase guideline concentrations in most cases’.
Therefore, any chemical toxicant trigger values would require reassessment and likely increase upwards
of any ANZG 2018 &/or ANZECC/ARMCANZ (2000) Guideline trigger values due to the slightly to
moderately disturbed nature (and thereby reduced sensitivity) of the receiving waters.
In conditioning more onerous criteria, rather than the available marine chemical toxicant trigger value
criteria contained within the ANZG/ANZECC Guidelines, an unachievable constraint may be placed on the
development. This DMP has allowed for contingency measures to be incorporated into the treatment
and discharge system if required, including silt curtains to be installed within the receiving waterway
surrounding the discharge location, or further onsite treatment measures such as filtration, to prevent
and/or minimise as far as reasonably practicable the potential for release of suspended solid loads into
the broader receiving waterway.
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5 Dewatering methodology
5.1 Basement excavation and shoring
Based on preliminary information provided by Seymour Group, existing ground levels within the
proposed basement footprint are approximately RL 2.4 m Australian Height Datum (AHD). Excavations to
facilitate the basement construction are proposed to extend to an approximate depth of 3.5 m below
existing ground level (bgl), corresponding to an approximate elevation of ‐1.1 mAHD. Localised deeper
excavations may also be required for other structural elements (i.e. lift pit and footings) across the site.
It is understood the excavation/basement perimeter will generally be stabilised using a contiguous secant
pile wall, except in proximity of the proposed pool on the northern side (facing the vacant parkland to
the north of the site) and as such will limit the potential for ground movement and instability of
surrounding lands, services and structures (refer to Appendix C).
Groundwater seepage was not encountered at the time of drilling to a depth of 4.5 mbgl during the
Geotechnical Investigations on the site in 205 (PTG Consulting, 2025). However, ADG notes that, typically,
the groundwater levels in the area are encountered at levels of approximately RL 0.5 m to RL 1.0 m.
Fluctuations of +/‐ 0.5 m are typically noted in the area. Groundwater levels are also likely to be subject
to fluctuations associated with the seasonal and climatic conditions, as well as tidal variations and
significant rainfall events.
It is expected that the development will include a ‘tanked’ basement to prevent the requirement for a
permanent dewatering facility at the site.
5.2 Groundwater extraction
Dewatering is anticipated to be undertaken using a series of 40 mm diameter PVC spears installed at
1.5 m intervals around the internal and external perimeter of the excavation. Alternatively, well point
dewatering may be appropriate within the internal face of the shoring wall. The final dewatering method
is subject to engagement of a shoring and dewatering contractor, as different contractors may specialise
in different methods of achieving the required dewatering drawdown. Preference should be given to
dewatering primarily on the internal face of the shoring wall, with preference for minimal dewatering
external to the shoring system to assist in minimising the extent of the cone of depression in the water
table (unless expressly required to limit hydrostatic force on the shoring system) and thereby limit
potential ground movement that may affect surrounding structures and services.
The basement excavation must be dewatered to a minimum of approximately 1.0 m below the deepest
point of excavation to allow construction to be undertaken in dry conditions. The water table (approx.
0.5 mAHD) is therefore expected to be lowered by at least 2.6 m in the locality of the basement
excavation footprint to a maximum of approximately ‐2.1 mAHD throughout the basement footprint.
Deeper localised dewatering may be required for the installation of a lift overrun pit and/or other
structural elements.
It is proposed that the development will include a ‘tanked’ basement to prevent the requirement for a
permanent dewatering facility at the site. Similarly, no permanent groundwater dewatering is proposed
or likely to occur as a result of the development, with all services and pipework proposed to be situated
above standing groundwater elevations (that is, at elevations above 0.5 mAHD) and subject to the
nominated hold points at Section 5.7. Where any deviation is proposed from this arrangement, all
pipework within the saturated zone, that outlets direct to waterways must be fitted with buried
headstocks at suitable intervals to prevent ongoing dewatering of groundwater along pipework bedding.
5.3 Extraction/discharge rates and volume
5.3.1 Dewatering extraction calculation based on subsurface soil profile
The dewatering extraction rate, area of influence and cone of depression has been estimated using the
Western Australian Department of Water and Environmental Regulation Cone of Depression Calculator.
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The calculation results are based on the following parameters and known site‐specific conditions:
Approximate length of excavation = 36 m
Approximate width of excavation = 17 m
Reduction in depth of groundwater across the excavation = 2.6 m (based on an approximate
groundwater depth of 0.5 m AHD)
Approximate depth of saturated thickness of unconfined aquifer = 10 m (conservative standardised
approximation)
A conservative soil profile of fine to medium grained sands, has a hydraulic conductivity of approximately
8.2 m/day, or equivalent 0.0000949 m/sec (WA Calculator). The results of the calculation are shown in
Table 4 below, and provided in Appendix D.
Table 4 Dewatering extraction rate results
Output Result
Effective radius of pumping well (m) 14
Dewatering radius of influence (m) 76
Discharge rate (L/sec) 8
Discharge rate (L/hr) 28,600
Establishment of cone of depression (hours) 102
Based on the above inputs, a groundwater flow rate of approximately 480 L/min or 28,600 L/hr has been
predicted for the development. Flow rates are predicted to be highest during initial drawdown of the
groundwater table within the basement excavation footprint and reducing to approximately 5 – 6 L/sec
following establishment of the cone of depression within the excavation. Flow rates may fluctuate due
to tidal variations, generally approximately ± 0.5 m, and will also be influenced by rainfall and surface
water collection within the basement excavation footprint noting the underlying predominantly sand
profile encountered during geotechnical investigations.
Regardless of the contractor employed, groundwater treatment systems should be installed with
capability for treating flow rates of up to 8 to 10 L/sec, as a contingency against higher than anticipated
flow rates exceeding the estimated 7 L/sec as a result of varying ground conditions across the extent of
excavation.
However, it should be noted that the WA Calculator provides a conservative assessment of inflows to an
excavation footprint based on area and depth but does not take account of the shoring wall, which will
inhibit lateral inflows to some extent. Also note that the cone of depression radius measure includes
water table depressions of 1 mm depth or more, so any significant depression of the water table is limited
to much closer to the dewatering spears or wells (generally within 3 to 10 m from the shoring wall in fine‐
medium grained sands, depending on density of the strata).
5.4 Dewatering duration
Dewatering will be necessary throughout the basement construction phase, which is expected to require
continual dewatering for approximately eight to twelve weeks. To minimise the potential impacts during
construction of short‐term dewatering, periods of active dewatering will be minimised as much as
possible. However, ADG notes that once active dewatering has commenced, dewatering will not be able
to be ceased until both: a) the basement hydrostatic uplift forces have been compensated to the
satisfaction of the consulting RPEQ engineer; and b) potential hydraulic loading on the external face of
the shoring system has been compensated to the satisfaction of the consulting RPEQ engineer and
shoring contractor.
5.5 Groundwater drawdown
Groundwater drawdown caused by dewatering has the potential to create settlement in unconsolidated
sediments and loose sands. It is noted that dilapidation reports for surrounding structures and services
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are proposed to be undertaken which were not supplied to ADG for the purposes of preparing this DMP
and are to be provided to Council separately from this DMP.
Groundwater drawdown may also oxidise potential acid sulfate soils within the cone of depression,
subsequently producing acidic groundwater conditions and mobilising heavy metals. Monitoring of the
extracted untreated groundwater will be undertaken to detect in‐situ oxidation of soils, as required and
at the frequencies stated in Section Error! Reference source not found.. Groundwater monitoring bores
for groundwater level gauging external to the excavation footprint are expected to be unable to be
established and monitored prior to and during construction on the site, due to limited space (SCG
Consulting Engineers).
Civil Engineering plans of the proposed development and basement arrangement are provided at
Appendix C.
5.6 Groundwater treatment
All extracted groundwater will be treated on‐site using available technologies prior to discharge to the
stormwater network. The following treatment measures (or similar depending on final dewatering
contractor selection) will be adopted, and will be installed and operational prior to the commencement
of dewatering:
1. A groundwater pH buffering treatment system (primary treatment)
2. A sedimentation tank to provide additional residence time and sedimentation (secondary
treatment)
3. A fine media filtration system designed for effective removal of heavy metals (tertiary treatment),
tertiar
if required.
Details of the treatment systems and methodologies are provided in Section 6 of this report.
Note: Consideration should be taken regarding placement of treatment gear on site to enable easy
cleaning and maintenance throughout the dewatering phase for the project. Consider the potential
requirement for regular de‐sludging of sedimentation tank/s to suitable area onsite, if available (cost
minimisation).
5.7 Nominated Hold Points
In accordance with anticipated DA Conditions, nominated hold points to be enacted during construction
have been proposed to facilitate for certification by the suitably qualified person experienced with Acid
Sulfate Soils, as well as Council Development Engineer to ensure all possible avenues for continual
dewatering below permanent groundwater level, including around pipework bedding that outlet to
waterways, are appropriately sealed. The nominated hold points regarding dewatering for this project
are:
1. Prior to commencement of dewatering/initial pump out
2. At finished excavation level, prior to blinding layer application
3. External to basement service installation trench opening/s prior to backfilling.
The above nominated hold points are subject to confirmation by the consulting engineer, and liaison with
council representatives and the Site Manager.
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6 Water quality management
6.1 Responsibility
The Site Manager is ultimately responsible for implementing the water quality management procedures
described in this DMP.
6.2 Operational policy
To prevent impacts on the receiving waters by effectively treating all extracted groundwater prior to
discharge from the site.
6.3 Performance criteria
The performance criteria for the discharge of extracted groundwater are the water quality objectives
provided in Table 2 and Table 3 in Section 4 of this report. Both the discharge and receiving waters (within
a 20 m radius of the stormwater discharge point) will be assessed against the WQOs to ensure that the
environmental values of the receiving waterway are maintained. Receiving waters data will also be
assessed against background monitoring data if non‐compliant results are obtained at the receiving
waters monitoring location.
6.4 Implementation strategy
All extracted groundwater will be treated on‐site using available technologies prior to discharge to the
stormwater network/canal. The treatment system described in Section 6.4.1 (below) will be adopted,
installed and operational prior to the commencement of dewatering.
6.4.1 Groundwater treatment systems
Subject to final appointment of shoring and dewatering contractors (who all generally have different
treatment systems), the following treatment systems are generally proposed for dewatered groundwater
treatment prior to discharge. Regardless of the contractor employed, groundwater treatment systems
should be installed with capability for treating flow rates of up to 8 to 10 L/sec, as a contingency against
higher than anticipated flow rates exceeding the estimated 7 L/sec as a result of varying ground conditions
across the extent of excavation or construction during wet weather.
Primary treatment
Groundwater treatment system/s will be installed to provide primary treatment of the extracted
groundwater. The system/s will provide the following capabilities:
1. A pH treatment tank with 5 kL minimum capacity.
2. Automated in‐line chemical dosing systems for the addition of buffering solutions and coagulants.
3. A filtration system to reduce fine particulates and heavy metals (in particular iron and aluminium in
both dissolved and total forms).
4. Emergency response alarms for non‐routine situations.
Based on the estimated extraction rate, this system will provide approximately ten minutes contact time
during the initial chemical dosing, prior to secondary treatment using a sedimentation tank. Primary
treatment tank will be vertically stacked on the secondary treatment tank wherever practicable to
minimise site area required for groundwater treatment equipment.
Secondary treatment
A 23 kL sedimentation tank will be utilised to provide the necessary residence time for secondary
treatment of the groundwater prior to discharge to the stormwater system. Based on the estimated
groundwater extraction rate of approximately 28,600 L/hr (equivalent 480 L/min) from Section 5.3.1 of
this report, one sedimentation tank will provide approximately forty‐seven minutes retention time
following primary treatment of the extracted groundwater. This is considered to be sufficient secondary
settling / retention time based on extensive prior experience on other sites in similar ground conditions.
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Tertiary treatment (if required) – may be required following initial testing of extracted groundwater
A specialised fine media filtration system designed for the effective removal of both total and dissolved
forms of heavy metals, with particular specific retention of iron and aluminium, will be utilised to remove
heavy metals from the secondary treated groundwater prior to discharge to the stormwater system. The
system will be capable of backflushing on manual or automated basis with retained concentrated heavy
metal suspended solids diverted to a backflush tank for further settling/thickening prior to offsite removal
by licenced liquid waste contractor for lawful disposal at a licenced disposal facility. This type of fine
media filtration treatment system is a forced‐flow system under pressure, and generally capable of
treating flow rates of up to 20 L/sec per filtration unit (therefore residence time is inconsequential to
treatment quality achieved).
Tertiary treatment will only be required if the required water quality is unable to be achieved following
primary and secondary stages of treatment. Subject to the results of field and laboratory testing during
the pre‐discharge monitoring event.
6.4.2 Dewatering strategy
The Site Manager, Dewatering Contractor and ADG Consulting will, if practicable, formulate a dewatering
strategy to ensure that the dewatering treatment system is sufficient to meet the requirements of the
project and that the necessary equipment can be accommodated within the site prior to the
commencement of dewatering.
Where the construction of the proposed development requires occupation of the road reserve (verge
area and/or road formation) for either short term or long term, a road reserve permit must be obtained
from Council prior to any occupation of the road reserve.
6.4.3 Initial pump‐out
Prior to, or as soon as practicable following the initial, discharge of any extracted groundwater to the
canal system, the following pre‐dewatering procedure will be undertaken:
1. The basement area will be excavated down to the standing groundwater level.
2. The initial dewatering discharge will be directed (via the treatment systems) into the excavation and
allowed to infiltrate/recharge the aquifer. This process will provide initial clarification of the
extracted groundwater as disturbed sediment loads are typically reduced following the initial pump‐
out.
3. Samples of the treated groundwater will be recovered and analysed for the parameters detailed in
Table 2 and Table 3. Note: ADG must be provided reasonable notice in order for this step to be
undertaken.
4. The extracted groundwater will be directed, or recommended to continue discharge, into the
stormwater system following confirmation that the water quality complies with the discharge
criteria. Or other recommendations will be provided, as required.
6.5 Monitoring
6.5.1 Visual monitoring
Visual inspections of the site and dewatering equipment shall be undertaken daily by the Site Manager
to identify the following:
Quantity of chemical product within the dosing system.
Effective operation of all dewatering treatment equipment.
Short circuiting of water around baffles and filter media in sediment tanks, where required to be
installed.
Visible hydrocarbon sheens and odours.
Green blue or extremely clear water indicating high levels of dissolved aluminium.
6.5.2 Water quality monitoring
Water quality monitoring will be undertaken for the duration of dewatering activities at the site by a
suitably qualified, experienced and independent person. The monitoring will include analysis of the
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extracted groundwater, treated discharge water and off‐site monitoring in the receiving waters (in the
mixing zone within a 20 m radius of the discharge point). The exact location within the receiving waterway
(Noosa River) is to be confirmed. Background water quality monitoring of field parameters will also be
conducted during each sampling event, if applicable. Background samples will be recovered from the
Noosa River, either upstream or downstream from the receiving water location (tide dependant)
approximately 300 m upstream of the discharge point).
The proposed monitoring locations are shown in Figure 1, Appendix A and are subject to confirmation
following mobilisation of dewatering equipment to site.
Monitoring will be undertaken at the following frequencies:
Daily monitoring of field parameters (pH, and turbidity) in the treated discharge water. Daily
monitoring will be undertaken by a suitably trained site employee under the supervision of the Site
Manager.
Weekly monitoring of field parameters (pH, electrical conductivity, dissolved oxygen, temperature
and turbidity) in the treated discharge water, receiving waters and background waters by ADG
Consulting.
Weekly laboratory analysis of treated discharge water and receiving waters for suspended solids,
dissolved 0.45µm filterable metals (aluminium, arsenic, cadmium, chromium, copper, iron, lead,
nickel, zinc and mercury) and total metals (aluminium & iron) by ADG Consulting.
Pre‐discharge/initial monitoring of field parameters (pH, electrical conductivity, dissolved oxygen
and oxidation‐reduction potential) in the extracted groundwater (prior to treatment) to assess
changes in groundwater chemistry associated with PASS oxidation (sampled by ADG Consulting).
Pre‐discharge/initial laboratory analysis of extracted groundwater (prior to treatment) for
suspended solids, dissolved 0.45µm filterable metals (aluminium, arsenic, cadmium, chromium,
copper, iron, lead, nickel, zinc and mercury), total metals (aluminium and iron) and for soluble
sulfate and chloride to assess changes in groundwater chemistry associated with potential acid
sulfate soil (PASS) oxidation (sampled by Environmental Consultant).
Laboratory analysis of untreated groundwater would also be performed periodically (monthly) if
changes in untreated groundwater pH levels are detected that may indicate local acidification, and
to determine any changes in local groundwaters that may require further investigation of potential
environmental impacts.
All samples will be recovered by a suitably qualified Environmental Scientist and submitted to a National
Association of Testing Authorities (NATA) accredited laboratory for analysis.
6.5.3 Monitoring responsibilities
The persons responsible for undertaking the compliance monitoring described in Section 6.5.2 above are
shown in Table 5.
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Table 5 Monitoring responsibilities
Activity Frequency Responsibility Person
Monitoring of field parameters in discharge water Daily Site Manager Site Manager
Monitoring of field parameters in discharge water, Environmental Environmental
Weekly Consultant
receiving waters and background waters Consultant
Laboratory analysis of samples recovered from discharge Environmental Environmental
Weekly Consultant
water and receiving waters Consultant
Monitoring of field parameters in extracted groundwater Initially, then as Environmental Environmental
(pre‐treated) required Consultant Consultant
Laboratory analysis of samples recovered from extracted Initially, then as Environmental Environmental
groundwater (pre‐treated) required Consultant Consultant
6.6 Maintenance
The groundwater treatment systems must be regularly maintained. Maintenance must include:
Regular cleaning and or replacement of the filter media within the filtration unit, where required to
be installed.
Regular removal of sediment from the sedimentation tank and backflush tank. The sediment must
be either returned to the excavation pit for dewatering and bulking out with excavated material, or
removed from the site by a licensed liquid waste contractor.
Regular/required back flushing of fine media filtration treatment system.
Regular check of the dosing system and top‐up of buffering solutions, oxidants and flocculants.
6.7 Reporting
Dewatering management procedures and monitoring results will be reviewed by ADG Consulting weekly
to ensure that the treatment procedures are effective, and that the receiving waters are not being
impacted by the discharge.
The following reporting procedures will be adopted:
A summary report will be prepared upon completion of the initial pre‐discharge monitoring. The
report will be submitted to the Site Manager, Dewatering Contractor and NSC (upon request).
Weekly interim reports will be prepared upon receipt of laboratory data for each round of ongoing
compliance monitoring. The interim reports will display all data obtained during the previous
monitoring event, and provide comments and recommendations based on the results.
A dewatering compliance report will be prepared on completion of the project (upon request).
The above reports will be prepared by the Environmental Consultant and provided to the Site Manager
and Dewatering Contractor as they become available. The reports will include all water quality results
and comparison to the WQOs, corrective actions and recommendations made to the Site Manager and
Dewatering Contractor during the monitoring period.
The Site Manager must keep records of complaints, volumes of chemicals used and treatment methods
employed. These records must be available on‐site at all times and submitted to NSC by the Site Manager
upon request.
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6.8 Contingencies
If water quality monitoring indicates ongoing exceedances of the performance criteria, and the water
quality objectives for the receiving waters cannot be met, then corrective actions will be adopted as
necessary. Possible contingencies may include one or more of the following:
Installation of additional sedimentation tanks to provide increased residence time and assist with
the retention of precipitated iron hydroxides.
Installation of additional flocculant and/or coagulant dosing systems to assist in precipitation of
suspended sediments and/or heavy metals.
Installation of activated carbon filtration or other additional fine media filtration to retain
suspended sediments and/or other specific target contaminants.
Install a floating sediment curtain/s around the stormwater termination point in the receiving
waterway to prevent unsightly plumes and contain sediment and/or heavy metals for periodic
removal (subject to approval by Council).
Preventive and corrective actions shall be taken in the event that groundwater monitoring
observations indicate that unexpected groundwater contamination has been encountered during
dewatering. The most appropriate action(s) shall be dependent on the stage of construction and
risk of adverse impacts to groundwater users and the receiving environment.
Any modification to the dewatering system and pumping rates shall be in consultation with a
suitably qualified scientist/geotechnical/engineer.
Following heavy rainfall all ponded surfaces waters to meet discharge criteria (Table 3) prior to
offsite discharge. Where discharge criteria not met, Site Manager to obtain approval from
Dewatering Contractor regarding treating surface waters with treatment gear before offsite
discharge.
Pumping systems and shoring works to be maintained in fit for purpose state by Dewatering
Contractor. In the event that dewatering equipment has failed and is likely to cause a significant
impact on the environment, or surrounding properties (E.g. flooding) the Dewatering Contractor is
to be contacted immediately. The Principal Contractor, in consultation with the Dewatering
Contractor shall be responsible in rectifying the failure in a practicable time frame to minimise
potential impacts.
Equipment, spare parts, materials and tools necessary to manage aspects of the system/s which
present a high risk of significant impacts in the event of failure (if any) shall be readily available.
Construction vibrations could potentially cause settlement in the loose upper‐level sands, thereby
damaging nearby structures founded in these strata. Prior to commencement of construction on
site (including staged works), it is recommended that a detailed dilapidation survey be undertaken
to establish the condition of all existing adjacent structures, roads and services.
Accumulated sediments and heavy metals within the treatment system can be emptied to available
area onsite and bulked out during earthworks or alternatively removed from site by a licenced waste
removal contractor (sucker truck).
Acid sulfate soils on site are to be managed in accordance with a site based ASSMP.
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7 Noise & odour management
7.1 Responsibility
The Site Manager is responsible for ensuring the appropriate management of noise and odour during
dewatering operations.
7.2 Operational policy
To minimise noise and odour emissions generated from the site during dewatering.
7.3 Performance criteria
The appropriate criteria to measure the performance of dewatering management at the site are provided
below.
1. No noise or odour related complaints received from neighbouring residents or the community.
2. No degradation of air quality due to fumes or odours emanating from the dewatering process.
7.4 Implementation strategy
Noise and odour emissions will be managed as described in the following sections.
7.4.1 Noise
All dewatering equipment must be operated appropriately and maintained in good working order. All
dewatering systems and plant must be fitted with the appropriate noise reduction equipment to comply
with the performance criteria. Non‐complying dewatering plant will be replaced or repaired as necessary.
It is proposed to employ noise mitigation strategies including use of electric pumps and dewatering
systems rather than diesel powered equipment. Noise attenuation blankets and screens may be installed
around noise generating dewatering pumps and equipment where practicable, if required. Noise
monitoring equipment (unattended) will be installed by the site manager prior to commencement and
monitored for the duration of dewatering, if required.
7.4.2 Odour
All dewatering plant must be fitted with the appropriate emission reduction devices. Where practicable,
all dewatering plant will be sealed to prevent the release of odours to the atmosphere. Fine mist odour
control sprays will be applied to reduce offensive odours if complaints are received from neighbouring
residents.
7.5 Monitoring
An inspection of the site and dewatering equipment shall be undertaken daily by the Site Manager to
identify the following:
Excessive noise being generated by the dewatering systems and plant.
Strong or offensive odours being generated by the dewatering equipment and/or extracted
groundwater.
If required by Council, noise monitoring equipment (unattended, continuous logging) may need to be
installed by the Site Manager prior to commencement and monitored for the duration of dewatering.
The Environmental Protection (Noise) Policy 2019 (EPP(Noise)) identifies specific acoustic quality
objectives (noise criteria) to assist in preventing significant impacts on noise sensitive receptors and as a
guide to long‐term acoustic quality for sensitive receptors. The primary EPP(Noise) criteria relevant to
this investigation is outside a dwelling (i.e. adjacent dwellings), which should not have noise at levels in
the daytime or evenings greater than 50dB(A) LAeq, adj,1hr. This means that noise levels in the receiving
environment outside of nearby dwellings (i.e. on balconies) should not exceed an equivalent sound
energy as would be received from a one hour continuous sound of 50 decibels on the A‐weighted scale
(adjusted for tonal character perceptible by the human ear).
While this report has not been generated for the purpose of assessing compliance with the requirements
of workplace health and safety legislation, it is noted that a person conducting a business or undertaking
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must ensure that workers are not exposed to noise that exceeds the exposure standard for noise. The
exposure standard for noise is defined in the Work Health & Safety Regulation 2011 (QLD) as LAeq,8h of
85 dB(A) or an LC,peak of 140 dB(C). As such, it is considered appropriate to adopt these exposure
standards to assess average and peak noise generated at the site with the potential to affect exposure
levels of nearby sensitive receptors (noting there will be some attenuation between source and receptors
and actual noise experienced by receptors would need to be measured at the receptor location).
7.6 Reporting
The Site Manager must keep records of complaints, monitoring records (including continuous noise
monitoring data, where required to be monitored), and corrective and preventive actions/methods
employed for noise abatement. These records must be available on‐site at all times and submitted to NSC
by the Site Manager upon request.
7.7 Contingencies
If noise levels consistently exceed the performance criteria, temporary acoustic barriers will be
constructed around the offending dewatering systems and plant. Odour control sprays will be applied as
necessary to mask odour emissions if complaints are received from neighbouring residents. This may
include the direct injection of deodorisers to the groundwater treatment system.
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8 Limitations
ADG Consulting Pty Ltd (ADG) has prepared this report for Seymour Group in accordance with the agreed
scope of work. The services performed by ADG have been conducted in a manner consistent with the
normal level of care and expertise exercised by members of the environmental consulting profession. No
other warranty or guarantee, expressed or implied, is made as to the professional advice included in this
report.
This report is solely for the use of Seymour Group and ADG accepts no responsibility for the use of any
part of this report for any other purpose or by third parties, as it may not contain sufficient information
for the purposes of other parties or users. This report must only be presented in full, and may not be used
for any other objective, except where prior written approval is obtained from ADG. This report does not
comment on legal obligations, as legal advice can only be given by qualified legal practitioners.
The information contained in this report is provided to minimise potential impacts on the receiving
environment, however implementation of the described management procedures does not guarantee
that the objectives will be achieved.
The information contained in this report is considered to be accurate at the date of issue. Subsurface
conditions, including contaminant concentrations can change in space and time, either through natural
processes or by the accidental or intentional addition of contaminants to a site. Where conditions
encountered subsequently at the site are significantly different from those reported herein, ADG must
be notified and be provided the opportunity to review the conclusions and recommendations of this
report.
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9 References
ANZECC/ARMCANZ. 2000. Australian and New Zealand Guidelines for Fresh and Marine Water Quality.
Australian and New Zealand Environment and Conservation Council and Agriculture and Resource
Management Council of Australia and New Zealand.
ANZG. 2018. Australian and New Zealand Guidelines for Fresh and Marine Water Quality 2018. Australian
and New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia.
Bureau Proberts. April 2025. Drawing. Proposed Residence 7 Noosa Parade. 24048 – AR 00.01 – Rev 3.
Bureau Proberts. 2025.
DEHP. 2013. Queensland Water Quality Guidelines 2009, Version 3. Department of Environment and
Heritage Protection. Brisbane, Queensland, Australia.
DES. 2022. Noosa River environmental values and water quality objectives. Department of Environment
and Science. Brisbane, Queensland, Australia.
DES. 2018. Monitoring and Sampling Manual 2018, Version 2 July 2018. Department of Environment and
Heritage Protection. Brisbane, Queensland, Australia.
Government of Western Australia. 2025. Cone of Depression calculator. Department of Water and
Environmental Regulation. Accessed 29 April 2024, <https://www.wa.gov.au/service/environment/cone‐
of‐depression‐calculator>.
NHMRC. 2008. Guidelines for Managing Risks in Recreational Water. Australian Government, National
Health and Medical Research Council.
PTG Consulting. February 2025. Geotechnical Soils Investigation Report, Proposed Residential
Development, 7 Noosa Parade, Noosa Heads. PTG/01608 – 001 – Rev 0. PTG Consulting. 2025.
PTG Consulting. April 2025. Acid Sulfate Soil Investigation Management Plan, Proposed Residential
Development, 7 Noosa Parade, Noosa Heads. PTG/01608 – 002 – Rev 0. PTG Consulting. 2025.
QLD Government. 2019. Environmental Protection (Water & Wetland Biodiversity) Policy. Queensland
State Government.
SCG Consulting. May 2025. Operational Works for Residential Development Lot CP on BUP 10936 No. 7
Noosa Pde, Noosa Heads. Rev issued 1 May 2025. (see Appendix C).
ADG1777.25 Dewatering Management Plan_Rev0_01.05.25 Page 21
Document Set ID: 23735664
Version: 1, Version Date: 12/05/2025
Page 26
ADG Consulting Pty Ltd
Appendix A: Figures
Figure 1. Site location and proposed monitoring locations
ADG1777.25 Dewatering Management Plan_Rev0_01.05.25
Document Set ID: 23735664
Version: 1, Version Date: 12/05/2025
Page 27
Figure 1 - Site Location and Proposed Monitoring Locations (to be confirmed) A product of
Lot 0 on BUP10936, 7 Noosa Parade, Noosa Heads, Queensland.
26°23'7"S 153°4'60"E 26°23'7"S 153°5'33"E
Legend located on next page
0 50 metres
Scale: 1:3074
Printed at: A3
Print date: 29/4/2025
Not suitable for accurate measurement.
Projection: Web Mercator EPSG 102100 (3857)
For more information, visit https://qldglobe.information.qld.gov.au/help-info/Contact-
us.html
Includes material © State of Queensland 2025. You are responsible for ensuring that
the map is suitable for your purposes. The State of Queensland makes no
representation or warranties in relation to the map contents and disclaims all liability.
If imagery is displayed, imagery includes material © CNES reproduced under license
from Airbus DS, all rights reserved © 21AT © Earth-i, all rights reserved, © Planet Labs
PBC, 2023
Department of Natural Resources and Mines, Manufacturing, and Regional
26°23'30"S 153°4'60"E 26°23'30"S 153°5'33"E and Rural Development
Document Set ID: 23735664
Version: 1, Version Date: 12/05/2025
Page 28
Figure 1 - Site Location and Proposed Monitoring Locations (to be confirmed)
Lot 0 on BUP10936, 7 Noosa Parade, Noosa Heads, Queensland.
Legend Attribution
Includes material © State of Queensland (Department of Resources); ©
Places: My Places(1) Tunnels Commonwealth of Australia (Geoscience Australia); © 21AT, © Earth-i, all rights
reserved, 2025.
My Place 1
© State of Queensland (Department of Resources) 2023
Site Discharge
© State of Queensland (Department of Natural Resources and Mines,
Receiving Water
Manufacturing and Regional and Rural Development) 2025
Background Water (tide
© State of Queensland (Department of Resources) 2024
dependent)
Background Water (tide © State of Queensland (Department of Natural Resources and Mines,
Manufacturing and Regional and Rural Development) 2024
dependent)
Railway stations
Railways
Roads and tracks
Motorway
Highway
Secondary
Connector
Local
Restricted Access Road
Mall
Busway
Bikeway
Restricted Access
Bikeway
Walkway
Restricted Access
Walkway
Non-vehicular Track
Track
Restricted Access Track
Ferry
Proposed Thoroughfare
Green bridges
Bridges
Document Set ID: 23735664
Version: 1, Version Date: 12/05/2025
Page 29
ADG Consulting Pty Ltd
Appendix B: Licenced groundwater bore search results
ADG1777.25 Dewatering Management Plan_Rev0_01.05.25
Document Set ID: 23735664
Version: 1, Version Date: 12/05/2025
Page 30
Licensed DRDMW Bore Search (200 m radius) A product of
Lot 0 on BUP10936, situated at 7 Noosa Parade, Noosa Heads, Queensland.
26°23'1"S 153°4'51"E 26°23'1"S 153°5'36"E
Legend located on next page
0 100 metres
Scale: 1:4211
Printed at: A3
Print date: 17/4/2025
Not suitable for accurate measurement.
Projection: Web Mercator EPSG 102100 (3857)
For more information, visit https://qldglobe.information.qld.gov.au/help-info/Contact-
us.html
Includes material © State of Queensland 2025. You are responsible for ensuring that
the map is suitable for your purposes. The State of Queensland makes no
representation or warranties in relation to the map contents and disclaims all liability.
If imagery is displayed, imagery includes material © CNES reproduced under license
from Airbus DS, all rights reserved © 21AT © Earth-i, all rights reserved, © Planet Labs
PBC, 2023
Department of Natural Resources and Mines, Manufacturing, and Regional
26°23'33"S 153°4'51"E 26°23'33"S 153°5'36"E and Rural Development
Document Set ID: 23735664
Version: 1, Version Date: 12/05/2025
Page 31
Legend Attribution
Includes material © State of Queensland (Department of Resources); ©
Registered water bores Roads and tracks Commonwealth of Australia (Geoscience Australia); © 21AT, © Earth-i, all rights
reserved, 2025.
[RDMW and private] Motorway
Artesian bore © State of Queensland (Department of Natural Resources and Mines,
Highway Manufacturing and Regional and Rural Development) 2024
Artesian bore
Secondary
(abandoned but useable) © State of Queensland (Department of Natural Resources and Mines,
Connector Manufacturing and Regional and Rural Development) 2025
Artesian bore
(abandoned and Local © State of Queensland (Department of Resources) 2024
destroyed)
Restricted Access Road © State of Queensland (Regional Development, Manufacturing and Water) 2022
Artesian bore, ceased to
flow Mall
Artesian bore, ceased to Busway
flow (abandoned but
Bikeway
useable
Restricted Access
Artesian bore, ceased to
Bikeway
flow (abandoned and
destroyed) Walkway
Sub-artesian facility Restricted Access
Walkway
Sub-artesian facility
(abandoned but useable) Non-vehicular Track
Sub-artesian facility Track
(abandoned and
Restricted Access Track
destroyed)
Ferry
Surface water facility
Proposed Thoroughfare
Surface water facility
(abandoned but useable)
Railways
Surface water facility
(abandoned and
destroyed)
Places: My Places(1)
My Place 1
My Place 2
Green bridges
Bridges
Tunnels
Railway stations
Document Set ID: 23735664
Version: 1, Version Date: 12/05/2025
Page 32
ADG Consulting Pty Ltd
Appendix C: Drawings
ADG1777.25 Dewatering Management Plan_Rev0_01.05.25
Document Set ID: 23735664
Version: 1, Version Date: 12/05/2025
Page 33
THE SITE
Issue:
SCG HOLDINGS PTY LTD T/A
Unit 1/11 Project Ave,
Noosa Heads
Ph (07) 5455 5604
email:[email protected]
web:www.scg-engineers.com
ABN 68 669 675 790
Title:
Project
Date: Drawn Design
Checked: Drg No. Rev.
Rev. - 10.06.16
Document Set ID: 23735664
Version: 1, Version Date: 12/05/2025
Page 34
Issue:
Unit 1/11 Project Ave,
Noosa Heads
Ph (07) 5455 5604
DEBUILD T/A
email:[email protected]
web:www.scg-engineers.com
ABN 40 098 481 899
Title:
Project
Date: Drawn Design
Checked: Drg No. Rev.
Rev. - 10.06.16
Document Set ID: 23735664
Version: 1, Version Date: 12/05/2025
Page 35
Issue:
SCG HOLDINGS PTY LTD T/A
Unit 1/11 Project Ave,
Noosa Heads
Ph (07) 5455 5604
email:[email protected]
web:www.scg-engineers.com
ABN 68 669 675 790
Title:
Project
Date: Drawn Design
Checked: Drg No. Rev.
Rev. - 10.06.16
Document Set ID: 23735664
Version: 1, Version Date: 12/05/2025
Page 36
Issue:
SCG HOLDINGS PTY LTD T/A
Unit 1/11 Project Ave,
Noosa Heads
Ph (07) 5455 5604
email:[email protected]
web:www.scg-engineers.com
ABN 68 669 675 790
Title:
Project
Date: Drawn Design
Checked: Drg No. Rev.
Rev. - 10.06.16
Document Set ID: 23735664
Version: 1, Version Date: 12/05/2025
Page 37
Cut/Fill Summary
Name Cut Factor Fill Factor2d Area Cut Fill Net
VOLUME 1.000 1.000 867.32sq.m 2111.08 Cu. M. 43.22 Cu. M. 2067.85 Cu. M.<Cut>
Totals 867.32sq.m 2111.08 Cu. M. 43.22 Cu. M. 2067.85 Cu. M.<Cut>
1.73
1.
Issue:
SCG HOLDINGS PTY LTD T/A
SITE PREPARATION, EARTHWORKS & COMPACTION Unit 1/11 Project Ave,
DILAPIDATION REPORT: Noosa Heads
Ph (07) 5455 5604
email:[email protected]
web:www.scg-engineers.com
ABN 68 669 675 790
Title:
Project
Date: Drawn Design
Checked: Drg No. Rev.
Rev. - 10.06.16
Document Set ID: 23735664
Version: 1, Version Date: 12/05/2025
Page 38
Issue:
SCG HOLDINGS PTY LTD T/A
Unit 1/11 Project Ave,
Noosa Heads
Ph (07) 5455 5604
email:[email protected]
web:www.scg-engineers.com
ABN 68 669 675 790
Title:
Project
Date: Drawn Design
Checked: Drg No. Rev.
Rev. - 10.06.16
Document Set ID: 23735664
Version: 1, Version Date: 12/05/2025
Page 39
Issue:
SCG HOLDINGS PTY LTD T/A
Unit 1/11 Project Ave,
Noosa Heads
Ph (07) 5455 5604
email:[email protected]
web:www.scg-engineers.com
ABN 68 669 675 790
Title:
Project
Date: Drawn Design
Checked: Drg No. Rev.
Rev. - 10.06.16
Document Set ID: 23735664
Version: 1, Version Date: 12/05/2025
Page 40
RESIDENTIAL
DEVELOPMENT
Issue:
SCG HOLDINGS PTY LTD T/A
Unit 1/11 Project Ave,
Noosa Heads
Ph (07) 5455 5604
email:[email protected]
web:www.scg-engineers.com
ABN 68 669 675 790
Title:
Project
Date: Drawn Design
Checked: Drg No. Rev.
Rev. - 10.06.16
Document Set ID: 23735664
Version: 1, Version Date: 12/05/2025
Page 41
Issue:
SCG HOLDINGS PTY LTD T/A
Unit 1/11 Project Ave,
Noosa Heads
Ph (07) 5455 5604
email:[email protected]
web:www.scg-engineers.com
ABN 68 669 675 790
Title:
Project
Date: Drawn Design
Checked: Drg No. Rev.
Rev. - 10.06.16
Document Set ID: 23735664
Version: 1, Version Date: 12/05/2025
Page 42
RESIDENTIAL RESIDENTIAL
DEVELOPMENT DEVELOPMENT
RESIDENTIAL
DEVELOPMENT
Issue:
SCG HOLDINGS PTY LTD T/A
Unit 1/11 Project Ave,
Noosa Heads
Ph (07) 5455 5604
email:[email protected]
web:www.scg-engineers.com
ABN 68 669 675 790
Title:
Project
Date: Drawn Design
Checked: Drg No. Rev.
Rev. - 10.06.16
Document Set ID: 23735664
Version: 1, Version Date: 12/05/2025
Page 43
RESIDENTIAL
DEVELOPMENT
Issue:
SCG HOLDINGS PTY LTD T/A
Unit 1/11 Project Ave,
Noosa Heads
Ph (07) 5455 5604
email:[email protected]
PLUMBING ARTICULATION: web:www.scg-engineers.com
ABN 68 669 675 790
Title:
Project
Date: Drawn Design
Checked: Drg No. Rev.
Rev. - 10.06.16
Document Set ID: 23735664
Version: 1, Version Date: 12/05/2025
Page 44
Issue:
SCG HOLDINGS PTY LTD T/A
Unit 1/11 Project Ave,
Noosa Heads
Ph (07) 5455 5604
email:[email protected]
web:www.scg-engineers.com
ABN 68 669 675 790
Title:
PLUMBING ARTICULATION:
Project
Date: Drawn Design
Checked: Drg No. Rev.
Rev. - 10.06.16
Document Set ID: 23735664
Version: 1, Version Date: 12/05/2025
Page 45
ADG Consulting Pty Ltd
Appendix D: Cone of Depression Calculations
ADG1777.25 Dewatering Management Plan_Rev0_01.05.25
Document Set ID: 23735664
Version: 1, Version Date: 12/05/2025
Page 46
Calculator Input Length of excavation: |36 | Width of excavation: l17 | Drawdown required: |2.6 | Aquifer thickness"): | 10 | Hydraulic conductivity: |0.0000949 Results Effective pumping radius, Re : 14 Cone of depression radius, Rg : 76 Total pumping rate: 8 Pumping time required: 102 Document Set ID: 23735664 Version: 1, Version Date: 12/05/2025 metres metres metres metres metres/second metres metres litres/second hours
Used in these records
Reference Document - Dewatering Management Plan (For Stamping) MCU25/0053 & OPW25/0074Related documentApplication case desk ↗
Reference Document - Dewatering Management Plan (For Stamping) MCU25/0053 & OPW25/0074Related documentApplication case desk ↗
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