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ADG1304.21 Dewatering Management Plan_Rev1.1_17.12.24
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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
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W adgconsulting.com.au
Dewatering Management Plan
Proposed ‘Palazzesi’ Residential Development:
Lot 145 on N21859, 38 Mossman Court, Noosa Heads, Queensland
December 2024
Prepared for:
Metricon Homes QLD Pty Ltd
Acid Sulfate Soil Assessment On‐site Wastewater Management Contaminated Land Assessment & Remediation
Dewatering Management Environmental Management Plans Surface & Groundwater Investigation & Monitoring
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Report details
Project ref: ADG1304.21
ADG Project Contact: Michael Campbell
Report title: Dewatering Management Plan
Proposed ‘Palazzesi’ Residential Development:
Lot 145 on N21859, 38 Mossman Court, Noosa Heads, Queensland
Version: Rev1.1
Author(s): Michael Campbell
Reviewer: Michael Campbell
Client: Metricon Homes QLD Pty Ltd c/‐ SCG Consulting Engineers
Client contact: Tom Harrington
Distribution date: 17 December 2024
Distributed to: SCG Consulting Engineers
Copies: 1 PDF
ADG Consulting Pty Ltd
Michael Campbell BEnvSc, BSc[Hons],
DipProjMgt, DipOHS, DipBusMgt, DipBus(Quality Auditing)
MEIANZ, MALGA, MASSI
Director & Principal Environmental Scientist
Date: 17 December 2024
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 1
1.4 DMP OBJECTIVES 1
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 DOUGLAS PARTNERS PTY LTD 2021 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 9
5.1 BASEMENT EXCAVATION AND SHORING 9
5.2 GROUNDWATER EXTRACTION 9
5.3 EXTRACTION/DISCHARGE RATES AND VOLUME 9
5.3.1 DEWATERING EXTRACTION CALCULATION BASED ON SUBSURFACE SOIL PROFILE 9
5.3.2 DEWATERING DISCHARGE RATE BASED ON STORMWATER SYSTEM SIZE (ESTIMATION) 10
5.3.3 CONCLUSIONS ON EXPECTED EXTRACTION RATES 10
5.4 DEWATERING DURATION 10
5.5 GROUNDWATER DRAWDOWN 10
5.6 GROUNDWATER TREATMENT 11
6 WATER QUALITY MANAGEMENT 12
6.1 RESPONSIBILITY 12
6.2 OPERATIONAL POLICY 12
6.3 PERFORMANCE CRITERIA 12
6.4 IMPLEMENTATION STRATEGY 12
6.4.1 GROUNDWATER TREATMENT SYSTEMS 12
6.4.2 DEWATERING STRATEGY 13
6.4.3 INITIAL PUMP‐OUT 13
6.5 MONITORING 13
6.5.1 VISUAL MONITORING 13
6.5.2 WATER QUALITY MONITORING 13
6.5.3 MONITORING RESPONSIBILITIES 14
6.6 MAINTENANCE 14
6.7 REPORTING 15
6.8 CONTINGENCIES 15
7 NOISE & ODOUR MANAGEMENT 17
7.1 RESPONSIBILITY 17
7.2 OPERATIONAL POLICY 17
7.3 PERFORMANCE CRITERIA 17
7.4 IMPLEMENTATION STRATEGY 17
7.4.1 NOISE 17
7.4.2 ODOUR 17
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7.5 MONITORING 17
7.6 REPORTING 17
7.7 CONTINGENCIES 17
8 LIMITATIONS 18
9 REFERENCES 19
APPENDIX A: FIGURES
APPENDIX B: DRDMW LICENCED BORE SEARCH
APPENDIX C: DESIGN PLANS
APPENDIX D: DEWATERING CALCULATION OUTPUT
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1 Introduction
ADG Consulting Pty Ltd (ADG) was engaged by Metricon Homes QLD Pty Ltd to prepare a Dewatering
Management Plan (DMP) for the proposed residential development within property described as Lot 145
on N21859, situated at 38 Mossman Court, Noosa Heads, Queensland.
1.1 Proposed development
The proposed development comprises the construction of a two‐storey residential dwelling over a single
storey in‐ground basement carpark. The supplied information indicates that excavations to facilitate the
construction of the basement level will extend to a maximum of approximately 2.7 m below natural
ground levels (approx. 2.2 m AHD) to a maximum excavation elevation of approximately ‐0.5 m Australian
Height Datum (AHD). Localised deeper excavations may be required for the construction of other
structural elements (i.e. footings and pile caps), where required.
Groundwater seepage was recorded at 1.6 m below ground level, during preliminary geotechnical works
(drilling) on the site by Douglas Partners (2021). Given the sites proximity to the Noosa River (adjacent)
and the presence of groundwater, dewatering will be necessary to allow the basement 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 (ANZG), Canberra ACT,
Australia.
Australian and New Zealand Guidelines for Fresh and Marine Water Quality. 2000. Australian and
New Zealand Environment and Conservation Council and Agriculture and Resource Management
Council of Australia and New Zealand (ANZECC/ARMCANZ).
Environmental Protection (Water & Wetland Biodiversity) Policy 2019. Department of Environment
and Science (DES), Queensland Government.
Noosa River environmental values and water quality objectives. 2022. Department of Environment
and Science (DES), Queensland Government.
Guidelines for Managing Risks in Recreational Water. 2018. Australian Government, National Health
and Medical Research Council (NHMRC).
Monitoring and Sampling Manual 2018, Version 2 June 2018. 2018. Department of Environment
and Science (DES).
Queensland Water Quality Guidelines 2009, Version 3. 2013. The Department of Environment and
Heritage Protection (DEHP).
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:
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Describe the dewatering methodology, groundwater treatment, monitoring and reporting
procedures to be employed at the site during dewatering activities.
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 (where
available).
2. Review of geology and soil maps for the area.
3. Search of groundwater bores licensed by the Department of Regional Development,
Manufacturing and Water (DRDMW) within a 500 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.
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2 Site characteristics
2.1 Property description
The site is described as Lot 145 on N21859, and is situated at 38 Mossman Court, Noosa Heads,
Queensland. The site is understood to be currently occupied by a multistorey dwelling (Nearmap Imagery,
10 September 2021) which is planned to be demolished. The site is irregular in shape and has an area of
607 m2. The site locality 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 Mossman Court, then residential development, then Noosa River.
East Residential development.
South Noosa River, then reserve area, then residential development.
West Residential development, then Noosa River.
2.3 Topography
The site and surrounding land is considered to be generally level, with the site gently sloping towards the
Noosa River from the north to the south, southeast. Surface elevations range from 2.20 m to between
1.62 and 1.25 m AHD. Refer to Appendix C (Design Plans).
2.4 Geology & soils
The surface geology at the site is mapped as being Anthropocene aged 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 volcanic and metamorphic as reference through the detailed surface
geology (accessed via Queensland Globe online, 6 October 2021).
The Acid Sulfate Soils (ASS) mapping layer 1:100,000 Redcliffe to Teewah 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 limited field investigation has
been performed in this area (accessed via Queensland Globe online, 6 October 2021).
2.5 Hydrogeology
A search of groundwater bores licensed by DRDMW was conducted by ADG on 6 October 2021. The
search identified no licensed bores within a 500 m radius of the site. A map showing the bore search area
is provided 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. Groundwater beneath the site is likely to be hydraulically connected to
the river, therefore saline groundwater conditions are anticipated, and additional saltwater intrusion is
likely to occur during dewatering.
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3 Previous investigations
This DMP is based on site specific information sourced from the following, provided to ADG by Metricon
Homes QLD Pty Ltd:
Preliminary Geotechnical Investigation, Proposed Residence, 38 Mossman Court, Noosa Heads.
2021. Douglas Partners Pty Ltd. Ref: 206126.00.R.001.
Design Plans, Pallazzesi Residence, Lot 145, 38 Mossman Crt, Noosa Heads. SCG Consulting
Engineers. (December 2024).
A brief discussion of relevant soil and groundwater conditions is provided below.
3.1 Douglas Partners Pty Ltd 2021
A preliminary Geotechnical Investigation was undertaken at the site in July 2021 by Douglas Partners Pty
Ltd (DP).
3.1.1 Soils
A total of one (1) borehole (Bore 1) was drilled within the northern portion of the site (due to limited rig
access) to 6.0 m below ground level (bgl). Two additional dynamic cone penetrometer (DCP) tests were
carried out within the southern portion of the site.
The subsurface profile encountered generally comprised medium dense silty sand fill overlying medium
dense to dense silty sand fill to approximately 0.9 m in depth. Natural medium dense silty sand was
encountered to 3.7 m depth overlying dense silty sand to 4.7 m depth. Very dense silty sands were
encountered to the termination depth of 6.0 m (Bore 1 only). DP reports, that similar conditions were
reported within the DCP holes, with relatively loose conditions encountered to 1.5 m depth.
As part of the Preliminary Geotechnical Investigation (2021), Acid Sulfate Soil (ASS) samples were
collected at 0.25 m intervals in Bore 1 to 4.0 m depth. A total of sixteen (16) samples were collected for
ASS screening and four (4) samples were selected for further analysis by the Chromium Reducible Sulfur
suite (CRS). Titratable actual acidity (TAA) concentrations were reported to be between 9 moles H+/tonne
and 26 Moles H+/tonne, with one exceedance of the relevant QASSIT action criterion of 18 moles
H+/tonne in Bore 1 at 1.0 m depth. Therefore, actual acid sulfate soils (AASS) should be expected to be
present to at least 1.0 m depth bgl. Reported oxidisable sulfur concentrations reported as SCr ranged
from 0.06 %S to 0.18 %S, all above the relevant action criterion of 0.03% S. The results indicate the
presence of potential acid sulfate soils (PASS) to at least 3.25 m bgl.
ADG notes that the testing was limited to one borehole with ASS testing to 4.0 m depth. DP summarised
that within this depth profile both the existing sand fill and natural silty sands are considered to contain
ASS and that neutralisation, using ag lime or similar will be required at a rate of 9.5 kg/m3 for the upper
fill profile and at a rate of 12.5 kg/m3 for the natural silty sands on the site. In addition, to treatment of
the excavated soil, a guard layer of ag lime (rate 4 kg/m3) should be applied to the basement excavation.
It is expected that ASS impacted material will be excavated and removed from site for appropriate
treatment and disposal at a licenced facility due to available area constraints on site – further information
on the liming rate (if required) is available in Section 7.5.3 of the Preliminary Geotechnical Report
prepared by DP. Given that ASS material has been identified within the sub‐soil profile, any leachate
generated on the site must be suitably treated/neutralised before leaving the site and must not be
directly discharged to stormwater.
3.1.2 Groundwater
During drilling activities for the Preliminary Geotechnical Investigation, groundwater seepage/inflow was
encountered at 1.60 m depth below the ground surface, which corresponds to an elevation of
approximately 0.5 m AHD (Douglas Partners, 2021).
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3.2 Groundwater quality
In the absence of any localised monitoring well data, and based on numerous groundwater investigations
and dewatering monitoring projects that have been undertaken by ADG throughout the Noosa Coast
Region 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) provided in 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 Noosa River.
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4 Water quality objectives
4.1 Receiving environment
It is proposed to discharge extracted groundwater directly into the Noosa River adjacent to site.
Based on the stormwater mapping available via the Noosa Council Enterprise Mapping System
(Intramaps) there is a stormwater gully pit located north of 40 Mossman Court. This stormwater pit
terminates within the Noosa River (<60 m) directly north of the gully pit. The exact location of the
receiving waters/environment will be confirmed on commencement of dewatering; however, it is
considered most appropriate that the site will discharge directly to the Noosa River adjacent south.
The receiving environment in this location identifies as a moderately disturbed, middle estuary
environment. 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 enclosed
coastal/lower estuaries. 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) The
selected trigger values apply to moderately disturbed systems to provide a 95% level of species
protection for marine waters.
Environmental Protection (Water & Wetland Biodiversity) Policy 2019. 2019. Noosa River
environmental values and water quality objectives. DES.
Noosa River environmental values and water quality objectives. 2022. DES.
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. The EPP(Water) provides a framework for:
Identifying environmental values for Queensland waters, and deciding the water quality objectives
to protect or enhance those environmental values.
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
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.
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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. In addition, the receiving water quality within a
20 m radius of the discharge point entry to the receiving water 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
Dissolved oxygen (% saturation) ≥802
Suspended solids (mg/L) ≤501,2
Turbidity (NTU) ≤502
Litter None visible
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 Queensland & NSW.
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 criteria available
Arsenic 2.32*
Cadmium 5.52
Chromium 4.42
Copper 1.32
Iron No relevant ANZG criteria available
Lead 4.42
Nickel 702
Zinc 82
Mercury 0.42
Totals metals (µg/L)
Aluminium No ANZG criteria / 2003
Iron No ANZG criteria / 3003
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Table notes:
1. DES (2022). Noosa River environmental values and water quality objectives (canal, harbour or marina).
2. ANZG (2018). Supersedes ANZECC/ARMCANZ (2000) ‐ Marine water trigger values for 95% species protection.
3. Criteria subject to expected condition in Development Application (DA) notice by Noosa Shire Council.
* = Insufficient data to derive a reliable trigger value. Low reliability value adopted (refer ANZECC/ARMCANZ (2000) Section
8.3.7.
Although ADG has not been provided a copy of the DA notice and conditions for the proposed
development, based on previous dewatering projects in the Sunshine/Noosa Coast Region it is expected
that total iron and aluminium concentrations as listed in Table 3 (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 Sunshine/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
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
It is understood that the excavation/basement perimeter will be stabilised along the perimeter of the
basement excavation using interlocking steel sheet piles. Excavations to facilitate the construction of the
basement level will extend to a maximum of approximately 2.70 m below ground level (approx.
2.2 m AHD), which corresponds to a maximum elevation of ‐0.5 m AHD (basement floor level ‐
0.15 m AHD; allow 350 mm for slab). Localised deeper excavations may be required for construction of
other structural elements (i.e. footings & pile caps). Refer to Design Plans, Appendix C.
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 will be undertaken using a series of 40 mm diameter PVC spears installed to below maximum
excavation depth at 1.5 m intervals around the internal and external perimeter of the basement
excavation.
The basement excavation must be dewatered to a minimum of 1.0 m below the deepest point of
excavation to allow construction to be undertaken in dry conditions. The water table (approx. 0.5 m AHD)
is therefore expected to be lowered by minimum of approximately 2.0 m to around ‐1.5 m AHD.
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.
The calculation results are based on the following parameters (as provided by ADS) and known site‐
specific conditions. The following is applicable to the basement excavations spanning across the lot:
Approximate length of excavation = 23 m
Approximate width of excavation = 20 m
Reduction in depth of groundwater across the basement footprint/excavation = 2.1 m
Approximate depth of saturated aquifer = 16 m (standardised conservative value applied)
The soil profile comprised predominantly of fine to medium sands, has a hydraulic conductivity of
8.2 m/day, or equivalent 0.0000949 L/sec (WA Calculator). The results of this calculation are shown in
Table 4 below, and a copy of the output is provided in Appendix D.
Table 4 Dewatering extraction rate results
Output Result
Dewatering radius of influence (m) 61
Discharge rate (L/sec) 12
Discharge rate (L/hr) 43,200
Establishment of cone of depression (hours) 35
Based on the above inputs, a groundwater flow rate of approximately 12 L/sec or 720 L/min or
43,200 L/hr has been predicted for the development.
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 method of perimeter
piling i.e. sheet pile/concrete secant wall, which will inhibit lateral inflows. Also note that the cone of
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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 spear point dewatering spears (generally
within 3 to 10 m from the sheet pile wall in fine‐medium grained sands, depending on density of the
strata).
5.3.2 Dewatering discharge rate based on stormwater system size (estimation)
It is expected that the stormwater network on Mossman Court (designated stormwater discharge
location) has a maximum flow capacity of approximately 81 L/sec (i.e. based on a 300 mm diameter
stormwater network pipe and an unknown install grade, calculated using minimum grade of 0.5 % as per
AS 3500.3, however likely to be greater).
A conservative estimate of 12 L/sec or 43,200 L/hr has been calculated by ADG – refer to Section 5.3.1
above.
5.3.3 Conclusions on expected extraction rates
It is recommended that the conservative estimate of 43,200 L/hour be adopted based on the sand profile
encountered during the sub‐surface investigations onsite. Based on previous dewatering projects
undertaken by ADG and ADS within the area, it is anticipated that initial flow rates will reduce to between
500 – 650 litres/minute following the initial drawdown of the water table.
The estimated discharge rate as determined in the above section 5.3.1, is well below (14.8 %) the Council
stormwater infrastructure capacity estimate (81 L/sec), therefore it is considered unlikely that discharge
of extracted groundwater from the site to the stormwater network on Mossman Court will cause any
disturbance/damage to council infrastructure or risk to the public. The likelihood of overtopping the
stormwater network and/or adjacent gully pits is considered unlikely because any such occurrences
would be limited to instances of extreme rainfall intensity, which are generally of short duration, and in
such a circumstance stormwater runoff would be expected to first utilise the remaining stormwater
network capacity (some approximately 69 L/sec), and any excess flow would then drain via the kerb and
channel to adjacent gully pits.
Any risks to the public associated with the placement of dewatering equipment to enable discharge to
the designated stormwater gully pit, should be mitigated by fencing and signage, have appropriate
lighting in place for after site hours and may need pipe over ramps to the pathway and/or driveways
where header pipe is to be placed in roadside guttering.
5.4 Dewatering duration
Dewatering will be necessary throughout the basement construction phase, which is expected to require
dewatering for approximately 10 to 12 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 sheet pile 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. 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 potential in‐situ
oxidation, as required and at the frequencies stated in Section 6.5.2.
ADG1304.21 Dewatering Management Plan_Rev1.1_17.12.24 Page 10
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ADG Consulting Pty Ltd
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 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. Installation of fine media filtration to retain suspended sediments and/or heavy metals (tertiary
treatment), if required.
Details of the treatment systems and methodologies are provided in Section 0 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).
ADG1304.21 Dewatering Management Plan_Rev1.1_17.12.24 Page 11
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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 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. The treatment system described in Section 6.4.1 will be adopted, installed and
operational prior to the commencement of dewatering.
6.4.1 Groundwater treatment systems
Primary treatment
A groundwater treatment system will be installed to provide primary treatment of the extracted
groundwater. The system will provide the following capabilities:
1. A baffled 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 (if required)
4. Emergency response alarms for non‐routine situations.
Based on the estimated extraction rate, a 5 kL system will provide approximately seven minutes contact
time during the initial chemical dosing, prior to secondary treatment using a sedimentation tank.
Secondary treatment
A sufficiently sized 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 43,200 L/hr (equivalent 720 L/min) from section
5.3.3 of this report, a 23 kL sedimentation tank will provide approximately thirty‐two minutes retention
time following primary treatment of the extracted groundwater.
Tertiary treatment – may be required following initial testing of extracted groundwater.
A filtration treatment system with specialised fine filtration media and chlorine dosing will be utilised to
provide the required heavy metal removal (specifically for total and dissolved iron) where not
precipitated and retained within the sedimentation tank/s (secondary treatment). This treatment system
will provide tertiary treatment of the groundwater prior to offsite discharge.
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.
ADG1304.21 Dewatering Management Plan_Rev1.1_17.12.24 Page 12
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ADG Consulting Pty Ltd
6.4.2 Dewatering strategy
The Site Manager, Dewatering Contractor and ADG Consulting must 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.
6.4.3 Initial pump‐out
Prior to 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.
4. The extracted groundwater will be directed into the stormwater system following confirmation that
the water quality complies with the discharge criteria.
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 and independent person. The monitoring will include analysis of the 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, however it is anticipated to be directly south/adjacent of the site. Background
water quality monitoring of field parameters will also be conducted during each sampling event, if
applicable. Background samples will be recovered from the river, either upstream or downstream from
the receiving water location (tide dependant).
The proposed monitoring locations are shown in Figure 1, Appendix A are a subject to confirmation
following mobilisation of dewatering gear to site.
Monitoring will be undertaken at the following frequencies:
Daily monitoring of field parameters (pH, and turbidity) in the treated discharge water and pH of
the untreated extracted groundwater (to determine potential acidification). 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 untreated extracted groundwater, treated discharge water, receiving waters
and background waters by ADG Consulting.
ADG1304.21 Dewatering Management Plan_Rev1.1_17.12.24 Page 13
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ADG Consulting Pty Ltd
Weekly laboratory analysis of treated discharge water and receiving waters for suspended solids
and dissolved 0.45µm filterable metals (aluminium, arsenic, cadmium, chromium, copper, iron, lead,
nickel, zinc and mercury). Total aluminium and iron will also be analysed for, if required.
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.
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) and for soluble sulfate and chloride to assess changes
in groundwater chemistry associated with PASS oxidation. Total aluminium and iron will also be
analysed for, if required.
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.
Table 5 Monitoring responsibilities
Activity Frequency Responsibility Person
Monitoring of field parameters in discharge water
Daily Site Manager Site Manager
and untreated extracted groundwater
Monitoring of field parameters in untreated
Environmental
extracted groundwater, discharge water, Weekly ADG Consulting
Consultant
receiving waters and background waters
Laboratory analysis of samples recovered from Environmental
Weekly ADG Consulting
discharge water and receiving waters Consultant
Monitoring of field parameters in extracted Environmental
Weekly ADG Consulting
groundwater (pre‐treated) Consultant
Laboratory analysis of samples recovered from Initially, then as Environmental
ADG Consulting
extracted groundwater (pre‐treated) required Consultant
6.6 Maintenance
The groundwater treatment systems must be regularly maintained. Maintenance must include:
Regular cleaning and or replacement of the filters within the filtration unit, where required to be
installed.
Regular removal of sediment from the sedimentation 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 check of the dosing system and top‐up of buffering solutions and flocculants.
ADG1304.21 Dewatering Management Plan_Rev1.1_17.12.24 Page 14
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ADG Consulting Pty Ltd
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 extracted groundwater being discharged.
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 ADG Consulting 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.
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, other heavy metals and/or suspended sediments.
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 fine media filtration to retain suspended
sediments and/or heavy metals.
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 Noose Shire 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 are 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 and/or shoring contractor. In the event that dewatering equipment has failed and is
likely to cause a significant impact on the environment, or surrounding properties (i.e. 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
ADG1304.21 Dewatering Management Plan_Rev1.1_17.12.24 Page 15
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ADG Consulting Pty Ltd
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.
ADG1304.21 Dewatering Management Plan_Rev1.1_17.12.24 Page 16
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ADG Consulting Pty Ltd
7 Noise & odour management
7.1 Responsibility
The Project 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.
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; and
Strong or offensive odours being generated by the dewatering equipment and/or extracted
groundwater.
7.6 Reporting
Reporting will be undertaken as described in Section 6.7 of this report.
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.
ADG1304.21 Dewatering Management Plan_Rev1.1_17.12.24 Page 17
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ADG Consulting Pty Ltd
8 Limitations
ADG Consulting Pty Ltd has prepared this report for Metricon Homes QLD Pty Ltd 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 Metricon Homes QLD Pty Ltd 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.
ADG1304.21 Dewatering Management Plan_Rev1.1_17.12.24 Page 18
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ADG Consulting Pty Ltd
9 References
ANZG 2018. Australian and New Zealand Guidelines for Fresh and Marine Water Quality. Australian and
New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia.
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.
DES. 2019. Environmental Protection (Water & Wetland Biodiversity) Policy 2019. Department of
Environment and Science, Queensland Government. Brisbane, Queensland, Australia.
DEHP. 2013. Queensland Water Quality Guidelines 2009, Version 3. Department of Environment and
Heritage Protection. Brisbane, Queensland, Australia.
DES. 2018. Monitoring and Sampling Manual 2018, Version 2 June 2018. Department of Environment and
Science. Brisbane, Queensland, Australia.
Douglas Partners. 2021. Preliminary Geotechnical Investigation, Proposed Residence, 38 Mossman Court,
Noosa Heads. Ref: 206126.00.R.001.
Government of Western Australia. Cone of Depression. Department of Water and Environmental
Regulation. Accessed 25/01/24, https://www.der.wa.gov.au/your‐environment/acid‐sulfate‐soils/66‐
cone‐of‐depression.
NHMRC. 2018. Guidelines for Managing Risks in Recreational Water. Australian Government, National
Health and Medical Research Council.
Noosa Shire Council. Noosa Council Interactive Mapping, Stormwater Infrastructure. Accessed 6 October
2021
https://enterprise.mapimage.net/intramaps97/?project=Public&module=Noosa%20Plan%202020&conf
igId=64251f07‐9411‐4a61‐930e‐2bd9b45d8fff&startToken=8117c0c9‐fb07‐4d6a‐a629‐b82dc6c64537
ADG1304.21 Dewatering Management Plan_Rev1.1_17.12.24 Page 19
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ADG Consulting Pty Ltd
Appendix A: Figures
Figure 1 Site and proposed monitoring locations
ADG1304.21 Dewatering Management Plan_Rev1.1_17.12.24
Page 25
Figure 1. Site and proposed monitoring locations
Page 26
ADG Consulting Pty Ltd
Appendix B: DRDMW licenced bore search
ADG1304.21 Dewatering Management Plan_Rev1.1_17.12.24
Page 27
Licenced bore locations - 500 m radius A product of
38 Mossman Court, Noosa Heads, Queensland
26°23'15"S 153°4'35"E 26°23'15"S 153°5'24"E
Legend located on next page
0 100 metres
Scale: 1:4513
Printed at: A3
Print date: 6/10/2021
Datum: Geocentric Datum of Australia 1994
Projection: Web Mercator EPSG 102100
For more information, visit https://qldglobe.information.qld.gov.au/help-info/Contact-
us.html
Includes material © State of Queensland 2021. 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, 2019
26°23'49"S 153°4'35"E 26°23'49"S 153°5'24"E Department of Resources
Page 28
Licenced bore locations - 500 m radius
38 Mossman Court, Noosa Heads, Queensland
Legend Attribution
Maxar
Registered water bores [RDMW Road
Includes material © State of Queensland (Department of Resources); ©
and private]
Highway Commonwealth of Australia (Geoscience Australia); © 21AT, © Earth-i, all rights
reserved, 2021.
Artesian bore Main
Artesian bore (abandoned but © State of Queensland (Department of Resources) 2021
Local
useable) © State of Queensland (Regional Development, Manufacturing and Water) 2021
Private
Artesian bore (abandoned and
destroyed) Cities and Towns
Artesian bore, ceased to ow
Artesian bore, ceased to ow
(abandoned but useable
Artesian bore, ceased to ow
(abandoned and destroyed)
Sub-artesian facility
Sub-artesian facility (abandoned
but useable)
Sub-artesian facility (abandoned
and destroyed)
Surface water facility
Surface water facility (abandoned
but useable)
Surface water facility (abandoned
and destroyed)
Road Crossing
Bridge
Tunnel
Railway
Page 29
ADG Consulting Pty Ltd
Appendix C: Design Plans
ADG1304.21 Dewatering Management Plan_Rev1.1_17.12.24
Page 30
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
Page 31
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:
CONSTRUCTION NOTES
Project
Date: Drawn Design
Checked: Drg No. Rev.
Rev. - 10.06.16
CN
Page 32
CANAL TIMBER
JETTY
CONCRETE
BOLLARDS
0.50
0.50 0.75
0.75 1.00
1.00 1.25
1.25 0.500.49
TOP 1.50 OF CONCRETE
L
AL
BANK RAMP
1.5
W
0 EXISTING
0 236°19' 0.75
CK
1.5
RO
CONCRETE
1.38 2.22 230°48' RETAINER 6.212 1.0
NG
26.234 1.60
STEPS 0
TI
1.96 1.04
IS
1.2
WALL
1.74
EX
1.19
1.17 2.20 2.20 5
TIMBER 2.22 PAVERS 2.19
2.72
EXISTING 2.95
L
25
DECK
AL
2.
CONCRETE
W
PATIO 2.22
RETAINER
GATE 2.81
2.23
2.25
2.80
2.80 2.94
28
2.
2.80
POOL
EN
TWO STOREY
RD
PAVERS
03 '
.6 03
RENDERED HOUSE
GA
30 5°
2.80
137°23'
CONCRETE 29.05 IRON ROOFING
35
FL = 2.23 2.94
TE
27
RE
2. 2.84
NC
2.29
CO
2.17 2.83
PAVERS
.25 2.82
2.25 2 2.28
13
3.
2.28
TWO STOREY
BRICK HOUSE
PEBBLE GARDEN
GATE
TILE ROOFING
GARAGE
2.23 2.53
2.22 2.22
2.24
2.22
TWO STOREY
RENDERED HOUSE
2.60 2.23 IRON ROOFING
2.28
2.27
2.28
2.2
2.72
2.86
5
2.25
2.21
65
2.27
2.20
NG 2.
PAVERS 2.22
2.80
2.61
2.70
TI
THIS DRAWING AND ASSOCIATED DETAILS
57
IS
2.26 GARDEN 2.61
2.
2.24
EX
2.25 MUST BE READ IN CONJUNCTION WITH
2.82 2.91
2. 23
2.20 THE NOTES CONTAINED ON 0405-N.
24
2.23 2.83 2.88
2.
2.5.63
2.22
EXISTING
2.1 8
2.23
.50
2.81
9
2.20
2
2.86
2 . 7 9 2.74 2 2.30
2.19 2
.7 1
8° 1 5' 2.25 76°52'
GATE 2.75 2 .598 3.053
2.28 GARDEN 11 PAVED
2.17 2.20 2.19 DRIVEWAY
Issue:
2.22
2.25
2.23
2.10 2.09
2.18 2.07 REF NAIL IN
2.18 R/WATER EDGE/BITUMEN
R/WATER 2.15 OUTLET RL 2.10 AHD
SCG HOLDINGS PTY LTD T/A
OUTLET x2 IL=2.05 Unit 1/11 Project Ave,
2.02 Noosa Heads
IL=1.98 2.13 Ph (07) 5455 5604
2.11 email:[email protected]
1.99 web:www.scg-engineers.com
1.97 ABN 68 669 675 790
REF NAIL IN
EDGE/BITUMEN Title:
RL 1.97 AHD
Project
Date: Drawn Design
Checked: Drg No. Rev.
Rev. - 10.06.16
Page 33
236°19'
230°48' 6.212
26.234
03 '
.6 03
30 5°
137°23'
29.05
35
2.61 THIS DRAWING AND ASSOCIATED DETAILS
2.82 2.91 MUST BE READ IN CONJUNCTION WITH
2.88 2.20 THE NOTES CONTAINED ON 0405-N.
2.83
2.5.63
2.1 8
2.81
9
2
. 7 9 2.86 2.74
2
2.71
8° 1 5' 76°52'
2.75 2 .598 3.053
11
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
Page 34
Cut/Fill Summary
Name Cut Factor Fill Factor2d Area Cut Fill Net
VOLUME 1.000 1.000 449.97sq.m 865.64 Cu. M. 11.45 Cu. M. 854.19 Cu. M.<Cut>
Totals 449.97sq.m 865.64 Cu. M. 11.45 Cu. M. 854.19 Cu. M.<Cut>
1.5 0.75
.50 0 236°19'
1 230°48' 6.212 1.0
26.234 0
1.2
5
2 5
2.
RESIDENTIAL
DEVELOPMENT
03 '
.6 03
30 5°
137°23'
29.05
35
.25
2.25 2
2.2
5
2.25
2 .50
8° 1 5' 2.25 76°52'
2 .598 3.053
11
2.25
Issue:
SCG HOLDINGS PTY LTD T/A
Unit 1/11 Project Ave,
Noosa Heads
SITE PREPARATION, EARTHWORKS & COMPACTION
Ph (07) 5455 5604
email:[email protected]
web:www.scg-engineers.com
ABN 68 669 675 790
1.73
1.
Title:
DILAPIDATION REPORT: Project
Date: Drawn Design
Checked: Drg No. Rev.
Rev. - 10.06.16
Page 35
236°19'
230°48' 6.212
26.234
03 '
.6 03
3055°
137°23'
29.05
3
° 1 5' 76°52'
28 .598 3.053
11
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
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
Page 37
236°19'
230°48' 6.212
26.234
03 '
.6 03
3055°
137°23'
29.05
3
8 °1 5' 76°52'
2 .598 3.053
11
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
PLUMBING ARTICULATION:
Date: Drawn Design
Checked: Drg No. Rev.
Rev. - 10.06.16
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
Page 39
ADG Consulting Pty Ltd
Appendix D: Dewatering calculation output
ADG1304.21 Dewatering Management Plan_Rev1.1_17.12.24
Page 40
Cone of Depression calculator This tool can be used to calculate the groundwater cone of depression in potential acid sulfate soil areas. Last updated: 2 May 2023 Preliminary assessment of the radial extent of the cone of depression and pumping rates and times for all Related page dewatering operations is critical for assessing the risk of disturbing acid sulfate soils in potential acid sulfate soil areas Acid sulfate soils Broad-scale acid sulfate soil risk maps for several coastal regions of WA are accessible via Data WAG Provided by Empirical methods to calculate the radial extent of the groundwater cone of depression and pumping rates Department of Water and Environment and times for dewatering operations are outlined in National Acid Sulfate Soils Guidance: Guidance for the Requistion dewatering of acid sulfate soils in shallow groundwater environments Share Calculator f Xin & Input Length of excavation 23 metres Width of excavation 20 metres Drawdown required 2.1 metres Aquifer thickness") 16 metres Hydraulic conductivity: 0.0000949 metres/second Results Effective pumping radius, Re 12 metres Cone of depression radius, R,, 61 metres Total pumping rate 12. litres/second Pumping time required 35 hours