5. Environmental Site Management Practices

5.1 Overview

This section details the procedures for the management of potentially contaminated soil and groundwater during land disturbance activities. It includes control measures for management and mitigation of potentially adverse human health effects associated with exposure to contaminated media, and the control of discharges to air, land, and water.

5.2 Surface Water and Sediment Control

Erosion and sediment control shall be implemented by the Link Alliance as described in the Project Erosion and Sediment Control Plan (ESCP) (Appendix H of the CEMP). All surface water and sediment control and monitoring will be managed by the Link Alliance through the ESCP.

5.3 Soil Excavation and Disposal

5.3.1. General

Investigations of soil contaminant concentrations completed in support of this project (AECOM, 2012 and Golder 2014) identified that significant soil contamination was unlikely to be encountered during land disturbance works. There is however, the potential to encounter gravel like fill materials for which soil contaminant concentrations (of metals and heavy end hydrocarbons) are above applicable standards defined by the NES CS and AUP Permitted Activity Criteria. At that stage, there is no requirement for a remedial action plan to be produced for works within the project area. It is however possible that unexpected soil contamination or hazardous materials could be discovered during the land disturbance works. If unexpected soil contamination is identified the management practices outlined in Section 7 should be implemented.

5.3.2. Oversight/Supervision

The CLS will undertake regular inspection and/or supervise soil disturbance activities associated with the construction works.

5.3.3. General Disposal Requirements

Most of the spoil material generated as part of the Aotea Station main works will likely be removed from the works area and disposed off-site. Any natural soil materials, including Tauranga Group sediments and East Coast Bays Formation materials, have been assessed as suitable for disposal as cleanfill. Any fill material required to be removed from the works area will be removed from the site (to off-site disposal) immediately, or temporarily stockpiled in covered and/or bunded areas onsite (depending on the requirement for additional testing, if requested by the disposal facility). A summary of preliminary soil classifications for the project is provided in the following sub-sections

5.3.2.1 Cleanfill

Cleanfill is defined in the AUP (2019):

“Means natural material such as clay, gravel, sand, soil and rock which has been excavated or quarried from areas that are not contaminated with manufactured chemicals or chemical residues as a result of industrial, commercial, mining or agricultural activities. Excludes:

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Hazardous substances and material (such as municipal solid waste) likely to create leachate by means of biological breakdown;

Product and materials derived from hazardous waste treatment, stabilisation and disposal practices;

Materials such as medical and veterinary waste, asbestos, and radioactive substances;

Soil and fill material which contain any trace element specified in Table E30.6.1.4.2 at a concentration greater than the background concentration in Auckland soils specified;

Sulfidic ores and soils;

Combustible components;

More than 5% by volume of inert manufactured materials (e.g. concrete, brick, tiles); and

More than 2% by volume of attached biodegradable material (e.g. vegetation)”

A facility where cleanfill material is accepted for deposit, excludes:

Storage and use of cleanfill material within an earthworks site for the purpose of engineering contours for specific activities,

Placement of cleanfill material associated with road construction and maintenance activities, and

Onsite storage and use of overburden or aggregate by-product that is cleanfill material associated with mineral extraction activities.

Natural soil materials including Tauranga Group sediments and ECBF would be suitable for disposal as cleanfill and may be disposed at a consented disposal facility such as the Ridge Road Cleanfill (Pukekohe, Auckland), or to other project sites in the region (depending on their resource consent requirements). Please note that classification of cleanfill may vary in regions outside of Auckland.

5.3.2.2 Managed Fill

Managed fill is defined in the AUP as follows:

“Cleanfill type materialbutwhere the material may include soils which exceed permitted activity contaminant concentrations that will not result in any significant adverse effect on human health, surface water, or groundwater quality, including potable water sources.”

Disposal of managed fill must be to a facility authorised (by regulatory bodies such as Auckland Council or Waikato Regional Council) to receive the material. Fill materials within the works area are likely to be suitable for disposal as managed fill pending pre-approval before disposal at a particular facility.

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5.3.2.3 Contaminated Fill

For the purposes of this CDWP contaminated fill 3 comprises:

Hazardous materials in the form of household and industrial waste, organic waste or asbestos containing material.

Soil with contamination present above managed fill criteria.

It is proposed that all contaminated fill disturbed as part of the earthworks will be removed from site to a licenced facility. Disposal of contaminated fill must be to a landfill authorised to receive the material. Landfill acceptance criteria vary between waste facilities and these should be confirmed prior to the removal of soil from site.

Any spoil materials generated within the project area which cannot be accepted at a managed fill (due to site specific restriction) must be removed to a contaminated fill facility. Examples include Hampton Downs (Hampton Downs, Waikato) and Redvale Landfill (Silverdale, Auckland) facilities. Pre-approval will be required for these disposal locations.

5.3.2.4 Disposal Related Validation Sampling

The disposal facility will nominate the validation sampling required (each disposal facility holds individual requirements i.e. 1 sample per 1,000m 3 ). The CLS or appropriately qualified person (as

nominated and or agreed with the CLS) will validate the fill material by collecting soil samples and submitting them for laboratory analysis. The laboratory results will be used to determine the soil disposal locations.

5.3.4. Record Keeping

The following off-site soil disposal management and record keeping measures will be implemented by the Link Alliance:

A record of the soil location, depth, and volume of the material removed shall be kept for the purpose of being included in the Works Summary Report (WSR) to be prepared by the CLS, refer Section 8.

Records will also indicate whether the material was removed as cleanfill, managed fill or contaminated fill.

Irrespective of the disposal facility nominated, all vehicle movements including registration, estimated weight, and disposal location will be recorded.

Tracking documentation is to be signed prior to leaving the project area and checked at the waste disposal facility to track all material leaving the project area.

Transporting subcontractors are required to cover loads and take appropriate measures to control dust.

Trucks will be inspected prior to departing the site to ensure the load is adequately covered and any spillage is contained.

Receipts summarising soil disposal will be collated and provided to the CLS at the completion of the land disturbance activities for the main works.

3 For the purpose of this Contamination Delivery Works Plan the term ‘Contaminated Fill’ is interchangeable with the terms ‘Contaminated Soil’ and ‘Contaminated Material’.

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A record of any contaminated soil left in-situ including the soil location, depth and estimated volume shall also be recorded for the purpose of being included in the WSR.

5.4 Groundwater and Perched Water

Clean stormwater will be separated and diverted away from areas of ground disturbance. The ESCP for Aotea Main Works (Appendix H of the CEMP) details the erosion and sediment controls that are to be implemented to minimise the potential for clean stormwater to encounter contaminated soil.

Site water, including surface water that has been in contact with fill material, groundwater and perched water requiring removal is to be managed via the following methods:

Piped or pumped to a sediment control system or settlement tank(s) before being discharged to the stormwater system; Further treatment (i.e. flocculent additives, pH adjustment) in accordance with the procedures detailed in the Flocculation Treatment Management Plan (FTMP) for the works; and Testing in accordance with the Water Quality Discharge Monitoring Programme (WQDMP) included in the FTMP to confirm compliance with the criteria for discharge to stormwater.

Alternatively, site water shall either be disposed by licensed liquid waste contractor to a licenced facility or discharge to sewer (subject to approval by Watercare Service Limited). For discharges to sewer, monitoring shall be conducted in accordance with the applicable permit conditions, e.g. trade waste agreement requirements.

5.5 Dust Control and Monitoring

Dust control shall be implemented by the Link Alliance as described in the main works Air Quality Delivery Work Plan (AQDWP) (Appendix I of the CEMP).

5.6 Materials Importation

5.6.1. General

Materials will be required to be imported to the works area to complete the subgrade. Two sources of material are proposed, clean quarry materials and recycled crushed concrete aggregate. Material sourced from a consented facility quarry or supplier does not require testing. This material is considered to meet the definition of a cleanfill.

5.6.2. Crushed Concrete

Prior to materials acceptance the contractor will request the following information from the supplier:

Address of source site.

Copies of pre-demolition asbestos surveys.

Copies of asbestos clearance certificates prepared prior to demolition.

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This information will be reviewed by the CLS who will advise the Link Alliance regarding suitability. Additional testing of crushed concrete materials may be required to be undertaken to approve suitability. This will be agreed between the CLS and Link Alliance on a case by case basis.

The following verification and testing regime will be completed by the CLS in support of the acceptance of recycled crushed concrete aggregate.

The CLS (or appropriately qualified person) will complete daily site walkovers.

Visual observations will be made for the presence of plastic, metal, or other waste fragments such as potential asbestos sheeting.

Testing will be completed from stockpiled materials at the site at rate of one sample per 500m 3 .

Bulk samples of suspect asbestos-containing materials will be analysed via an appropriatelyaccredited laboratory.

Soil samples will be analysed via New Zealand Guidelines for Assessing and Managing Asbestos in Soil (BRANZ 2017) methodology.

Samples may be analysed for asbestos presence/absence as a screening measure, at the discretion of the CLS.

The Link Alliance and the CLS will retain records pertaining to materials importation completed. The CLS will use these records to complete the WSR (refer Section 8).

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