APPROVED Document - Concept Construction Management Plan · OPW11/0116

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International
Coastal

Management

 

Document Control Sheet

Prepared by Aaron Salyer

Title: Coastal Engineer

Company Intemational Coastal Management
Final Review Bobbie Corbett

Title Senior Coastal Engineer
Company Intemational Coastal Management
Approved for release Bobbie Corbett

Title Senior Coastal Engineer
Company International Coastal Management

Version History

 

Version No. Date | Changedby y
RevA 5.4.11 Bobbie Corbett Acid sulphate revised.
| Marine plants revised

 

|

 

|

This document has been produced by International Coastal Management Pty Ltd (ICM) in accordance with the terms and
limitations of the brief by SCRC. In preparing this report, ICM has used information provided by the Client and others
identified herein. ICM does not and shall not assume any responsibility or liability whatsoever to any third party arising out of
any use or reliance by any third party on the content of this document. This document is not to be used without the express
approval of SCRC

International Coastal Management + (CM)
via Arm. SYC Marina Main Be sony
Box 306 Main Beact! LF
vow +f 6A D584 1m +€

wuss wey COastaiman:

 

 

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International
Coastal woe
Management

 

TABLE OF CONTENTS

1, SITELOCATION....

 

2. INTENT OF CONCEPT CONSTRUCTION MANAGEMENT PLAN ........csssccsssesssssessstessssssssecsssrecsssucessunesssnnessinesssaees 2

3% DESCRIPTION AND PURPOSE OF WORKS sesssisssvvcsisiscveccsnssusinsensssvirastossvenesaveonousaciynnedynenunravensiniaieennnncennsienaueien

4, RELEVANT APPROVALG.........scsssessssesssssessssesonsecssssessssesssvscssveenssveessscessvscsssnsesssucsunvessircesaveesssereessseecansesesuneessseseanieee 3

 

5. CONSTRUCTION.. we
54 Equipment 4
5.2 Methodology for Dredging / Nourishment 4
5.3 Methodology for Filling Containers 4

6. SUMMARY OF KEY ENVIRONMENTAL ISSUES. ............cscssssssessseesnsesnesssessneesnscsnessueessesssssunensueessiesnsessseennsesnssenseaseses 4
61 Water Quality 5
6.2 Noise 5
6.3 Flora & Fauna 5
6.4 Acid Sulphate 7
6.5 Cultural Heritage 8
6.6 Waste Management 8
6.7 Air Quality Management 8
6.8 Flammable and Combustible Materials 9
6.9 Greenhouse Gas Emissions 9

7. ENVIRONMENTAL MANAGEMENT MONITORING REQUIREMENTS ........cssccssssssessssesssssesssneesssussssnssarsnsresssnecesneessse 9

8. CONTINGENCY PLANS & EMERGENCY PROCEDURES............:-000000

 

Intemational Coastal Management (CM)

ad 3 A Marna Main Beact

 

 

 

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1. SITE LOCATION

The site is located within the Noosa River entrance [Figure 1] adjacent to the Noosa River Spit. The works are located
outside the Noosa River Fish Habitat Area [Figure 2].

ee Ber sd

josa River
sh Habitat Area

& # if
Figure 2: Extent of Works

 

There is a tidal range of approx 2m [QT tide tables]. The site protected from ocean swell and seas by Noosa Spit and shoals
within the entrance. Spring tidal velocities within the southern channel can be up to 1.5m/s, although this may change with
channel configuration. The channels and shoal configuration is highly variable.

 

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2. INTENT OF CONCEPT CONSTRUCTION MANAGEMENT PLAN

This Concept Construction Management Plan is intended to provide an indication of how works may be undertaken by the
contractor, likely environmental impacts and intended control measures.

The contractor is to prepare a final construction management plan prior to commencing works and a copy is to be provided to
DERM. The contractor's methodology, plant, equipment, scheduling etc may vary from that indicated here. Any changes to

the intended methodology that may increase the impact of the works is not to be implemented without further discussion with

DERM.

3. DESCRIPTION AND PURPOSE OF WORKS

With the exception of those areas already protected by rock works, Noosa River Spit is currently experiencing erosion along
its full length, including the southern end of the Noosa River Spit. While this is reducing amenity along what was once a
popular recreational beach, there is also the potential for continued erosion to breach the Noosa River Spit, which could have
very serious impacts.

A number of options were considered [ICM 2010 report}. The preferred option includes [Figure 3}:
e Submerged curved “closure” [sand-filled geotextile mega-containers] designed to create an enclosed, stable
beach and lagoon area
Dredging for interim navigation and associated foreshore nourishment
Training wall [sand-filled geotextile mega-containers] to provide a control point for the southern channel
Wall [sand-filled geotextile mega-containers] to prevent erosion along southern end of the Noosa River Spit
Two groynes [2.5m3 sand-filled geotextile containers] to stabilize the upstream beach

 

 

Figure 3: Proposed Strategy

 

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A staged approach of construction is being adopted and this construction plan is relevant only for Stage 1 of the works
{Figure 4]. Stage 1 includes:

Retain existing rock wall [maintain / upgrade as required]
Submerged channel closure [partial]

Wall at end of Noosa River Spit

Groyne / Training Wall

Dredging for interim navigation (location to be determined)
Foreshore nourishment

Removal of dead trees (marine plants) as required
Widening of access track

e
°
°
.
.
.
.
.

The submerged channel closure, wall and groyne are to be constructed using sand-filled geotextile mega-containers.

 

 

 

: Proposed Stage 1 Works [preliminary design]

4. RELEVANT APPROVALS

The following approvals are being sought:

o Resource Entitlement

© Prescribed tidal works

o Interfering with Marine Plants
o ERA 16 1(b)

o Registration Certificate

°

Clearing (Nature Conservation Act)

 

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5. CONSTRUCTION

There are a number of ways in which these works could be achieved and the final methodology is at the discretion of the
contractor.

5.1 Equipment
It is anticipated that the works (depending on the methodology) may require the use the following major equipment:

6" or greater cutter suction dredger and pipeline
Jet pump (suspended or hopper-fed)

Barge

Support vessels

Excavator

Bobcat

5.2 Methodology for Dredging / Nourishment

The dredge area is to be located accurately using DGPS or suitable alternative. Dredging is to be undertaken slowly to
minimise turbidity. Dredging is to be undertaken in such a way that it does not block navigation once a suitable channel is
established.

Nourishment is to be achieved generally by relocating the pipeline periodically within the deposition area. Small earthmoving
equipment may be used to redistribute material on the visible beach to achieve final nourished profiles. This may be more
difficult to achieve given the presence of significant dead tree material on the foreshore. As the slopes are the same as
existing, final profiling below low tide will likely be achieved by tidal velocities

5.3 Methodology for Filling Containers

Filling sand-filled geotextile containers can be undertaken in a number of ways. The simplest methodology includes the
following

Dredge along the structure alignment to achieve the design depth

Roll out empty container

Secure in location with anchor blocks

Fill container using dredge (while excavating for the next container, per step 1)
Seal trunks

ArwWrn=

There are a number of potential variations to this generic methodology. These include:

Excavation for containers may source nourishment and container fill may be sourced from the dredging of channel
Containers may be filled using a jet-pump suspended from a barge-mounted excavator.

Containers may be filled from an onshore stockpile using a hopper-fed jet pump.

Material may be double handled in some cases.

A frame may be used to secure the container instead of anchor blocks.

Use of temporary bunds may be considered in some locations to stabilise containers during the initial stages of
filling. These are to be removed upon completion of the works where backfilling isn't necessary

It is noted that the works will require the use of divers.

Works will be tide and weather dependent

6. SUMMARY OF KEY ENVIRONMENTAL ISSUES

The works are adjacent to (but not within) the Noosa River Fish Habitat Area. The areas to be dredged are not within a
Marine Park

 

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The following outlines potential impacts of the works. Works are to be undertaken in such a way that impacts are minimized
wherever possible. Monitoring to ensure that any impacts are within acceptable levels is detailed below.

6.1 Water Quality
The dredge will operate in such a way to minimise turbidity during dredging operations.

To ensure that water quality [pH, DO, Turbidity] remains within acceptable limits, visual monitoring of the plume is to be
undertaken as well as any required water quality testing in accordance with ERA requirements. Visual observations for oil,
grease, floating scum and litter is to be carried out on a regular basis.

6.2 Noise

The works are separated from the businesses and resorts on Hastings St by at least 620m of well-developed vegetation. Itis
not anticipated that works will cause an issue in this area. The dredging, submerged closure and training wall / groyne, the
plant will be over 400m from the residences of Noosa Sound and separated by 60m of well-vegetated area on Noosa River
Spit. When undertaking the wall at the end of Noosa River Spit, the works will be within 350m of the residences on Quamby
Place (Noosa Sound) and noise could potentially be an issue, particularly outside of normal working hours.

The Contractor shall take all reasonable precautions (e.g. the use of mufflers) and undertake works in such a way as to
minimize the potential for noise nuisance to residences and businesses and meet the requirements of the ERA conditions:

Given the nature of the work and the environment, there will be a need to work in conjunction with the tides and so works
may need to be undertaken outside of normal working hours. There is no restriction on working hours provided that the
required noise limits are met.

An aural inspection is to be undertaken daily and if any issues are identified or complaints are made regarding noise levels,
Noise monitoring compared to nominated levels is to be undertaken if works are to continue in this area.

6.3 Flora

 

Due to the mobility of the channels and shoals and the high erosion rate, the area is characterized by a clean sandy seabed
(Figure 5). There are no seagrass beds present within the footprint of the proposed works,

 

   

Figure 5: Sandy shoal

The only mangroves within proximity of the works are at the south-eastern end of the wall at the end of the Noosa River Spit
(Figure 6). The wall terminates adjacent to the mangroves, but works are to be undertaken in such a way that no mangroves
are to be interfered with as part of the works.

 

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Due to the high rate of erosion there are a number of large dead trees along the length of the foreshore (Figure 7). These
are typically well-established trees. The number of trees is unknown, but they cover an area of approximately 7700m?
These trees are classified as marine plants as they are within the tidal zone. It will be necessary to remove these trees to
allow for construction

Where excavation is taking place, the full tree should be removed [although this may need.to be done progressively during
excavation] to prevent blockages of the dredge pipeline and ensure that organics are not used to fill the container or sharp
sections remain where they could potentially result in damage to the containers. In other areas {i.e. where nourishment is
taking place or within work areas], trees may be trimmed at the required depth [approx 0.3m below surface], sufficient to
allow for access without damage to equipment

 

 

  

Figure 7: Dead trees along Noosa River Spit

There is a reasonable access path to site from the carpark. Part of the works will include slight widening of this track as
required to allow access for construction equipment. Given the low-lying nature of the track, the majority of the trees will be
Classified as marine plants, however a small number adjacent to the carpark are above HAT and are not marine plants.

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Figure 8:Existing path to site

Arborists have advised that the following methodology would be most beneficial and is to be followed as much as

practicable:
« Removal of branches >6" diameter and placement within Noosa Spit and Noosa Woods (above HAT) as fauna
habitat

¢ — Heavy trimming of remaining trees, stockpiling and mulching. Mulch to be utilised for rehabilitation along access
track and site perimeter
e Removal of remainder of tree litter unsuitable for mulching for disposal at an appropriate location ashore

Removal of trees and mulching to be undertaken by separate, experienced contractors prior to commencement of other
works

 

An offset programme has been developed to compensate for the loss of habitat as a result of the works and this is provided
as a separate report.

6.4 Acid Sulphate

Sediment testing was undertaken on 4" and 5% January 2011 by Coffey Geotechnics. The sediment is fine-medium grained
sand with low (<5%) fines content

While the surface sediments are clean sand suitable for nourishment, acid sulphate soils (both AASS and PASS) were
identified within some of the deeper areas. Below is the table from the Coffey Report

The dredging for interim navigation and excavation for the construction of the submerged closure does not disturb acid
sulphate soils.

Dredging / excavation for the wall and training wall / groyne at the end of Noosa River Spit does disturb some acid sulphates
below RL-4.75m AHD. As such, all material dredged / excavated from below RL-4.5m AHD is to be placed below LAT (i.e
used for filling deeper containers or as backfill adjacent to the toe).

 

 

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Component of Works Depth Liming Rates (kg/m*}
Above RL 4 75 metres AHD Nil
Wall’ Groyne Below RL 4.75 metres AND 8
(S1-S4)
Below RL -5.5 metres AHD 50
around S4
Submerged Closure Above RL -6 45 metres AHD Nil
(35 - $7) Below RL -6 45 metres AHD 50
Oredging
Above RL -3 25 metres AHD Nil
($8 - S14)

 

 

 

 

 

ffote No disturbance is expected for the Submerged Closure area below RL -6 45 metres AHD or within ite
Dredging area below RL -3 25 metres AHD

6.5 Cultural Heritage

The Noosa River Spit was artificially reclaimed in 1978 and there has been significant dredging within the river over recent
yeats. There are no identified areas or Items of cultural significance within the proposed area of the works, although a
cultural study can be undertaken if required,

\f any potentially culturally significant items are found, the contractor will cease works immediately and advise the
Superintendent. The Superintendent will notify the traditional owners to seek their advice before works in that area can
continue.

6.6 Waste Management

The sandy material from dredging / excavation will be used for filling containers, backfilling and foreshore nourishment within
the vicinity of the works, The sediment type is very consistent across the footprint of the works and is suitable for this
purpose,

Other wastes (rubbish etc) may be temporarily stored on site if adequately contained. The Contractor is responsible for
ensuring that all waste is disposed of at suitable onshore facilities. Every effort is to be made to ensure that liter and other
debris does not enter the waters. Any material or objects dropped onto the bed are to be recovered. Visual monitoring is to
be undertaken,

 

The seabed is to be checked prior to completion of the works. All waste materials (including anchor blocks and ropes used
during construction) are to be removed and not buried or left on the seabed.

The contractor is to implement an oil spill management plan.

Itis not anticipated thal any regulated waste will be generated as part of the works.

6.7 Air Quality Management

Air emissions from plant and equipment are to be monitored visually to ensure air quality is acceptable throughout the works.
Exhaust is to be within the specifications of the equipment and all required maintenance is to be undertaken.

 

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6.8 Social

Any complaints are to be investigated and responded to in a prompt manner. The Superintendent is to be notified of any
complaints as soon as practicable. A suitable complaint register is to be kept

6.9 Flammable and Combustible Materials

A list of all flammable and combustible materials, chemicals or any other potentially hazardous substances is to be noted on
the MSDS register.

6.10 Greenhouse Gas Emissions

All machinery is to be regularly maintained and operated in accordance with specifications to minimise possible greenhouse
gas emissions.

7, ENVIRONMENTAL MANAGEMENT MONITORING REQUIREMENTS

Monitoring requirements are to be as below, in addition to any ERA Licence requirements

 

 

 

 

 

Issue _ Monitoring : Frequency/Timing _| Performance Criteria | Responsibility
Water Quality Visual Inspection Daily during dredging | No visible turbidity Contractor
hours plume from dredging
| >200m from the
dredge site

No visible oil, grease.
| floating scum or litter _

 

 

 

Noise Aural inspection of | Weekly during __| Noise levels in Contractor
equipment for dredging accordance with
excessive noise equipment

specification.
Investigation of noise | As required in | Complaints responded | Contractor
complaints response to any noise | to within 24 hours
ee _ complaints J _

Air Quality Visual inspection for Daily during dredging | No excess machinery | Contractor

excess machinery hours exhaust

 

ee exhaust emissions st pl _
Waste Management Visual inspection of Daily during dredging | No uncontained litter | Contractor
| site for floating debris | hours waste | |

for barge/dredge _

 

 

 

 

 

 

8. CONTINGENCY PLANS & EMERGENCY PROCEDURES

Should any non-confirming results be observed or recorded, works are to suspended immediately and the Superintendent is
to be notified. A procedure for non-conformance is prepared for each Project. This procedure incorporates:

Work Instructions issued

Non Conformance Report Form
Reporting Procedure
Corrective Action

 

A number of specific detailed contingency plans are to be prepared and include an oil spill management plan and a waste
management plan