Marine Dumping Consent Application and Impact Assessment
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MARINE DUMPING CONSENT APPLICATION AND IMPACT ASSESSMENT Scuttling of Dong Won 701 Fishing Vessel Within an Authorised Location South-east of Otago Harbour Prepared for: DW New Zealand Limited 145 Dawson Street Timaru Port Timaru 7910 SLR Ref: 740.10102.00000-R01 Version No: -v1.0 December 2019 DW New Zealand Limited SLR Ref No: 740.10102.00000-R01-v1.0.docx Marine Dumping Consent Application and Impact Assessment December 2019 Scuttling of Dong Won 701 Fishing Vessel Within an Authorised Location South-east of Otago Harbour PREPARED BY SLR Consulting NZ Limited Company Number 2443058 6/A Cambridge Street Richmond, Nelson 7020 New Zealand (PO Box 3032, Richmond 7050 New Zealand) T: +64 274 898 628 E: [email protected] www.slrconsulting.com BASIS OF REPORT This report has been prepared by SLR Consulting NZ Limited (SLR) with all reasonable skill, care and diligence, and taking account of the timescale and resources allocated to it by agreement with DW New Zealand Limited (the Client). Information reported herein is based on the interpretation of data collected, which has been accepted in good faith as being accurate and valid. This report is for the exclusive use of the Client. No warranties or guarantees are expressed or should be inferred by any third parties. This report may not be relied upon by other parties without written consent from SLR. SLR disclaims any responsibility to the Client and others in respect of any matters outside the agreed scope of the work. DOCUMENT CONTROL Reference Date Prepared Checked Authorised 740.10102.00000-R01-v1.0 18 December 2019 SLR Consulting NZ Limited Rob Lieffering Dan Govier Page 2 DW New Zealand Limited SLR Ref No: 740.10102.00000-R01-v1.0.docx Marine Dumping Consent Application and Impact Assessment December 2019 Scuttling of Dong Won 701 Fishing Vessel Within an Authorised Location South-east of Otago Harbour EXECUTIVE SUMMARY The vessel Dong Won 701 (the vessel) is an 81 m long, New Zealand flagged fishing vessel owned by the New Zealand company DW New Zealand Limited (DWNZ). The home port of the vessel is Timaru and the vessel has fished within various Fisheries Management Areas of New Zealand waters. In April 2018 the vessel suffered a serious fire which caused extensive damage, resulting in around 50 per cent of the vessel being ‘gutted’ thereby rendering it unusable and uneconomic to restore. The vessel is currently berthed at PrimePort, Timaru. Several options have been considered by DWNZ for the vessel. The only viable option is to tow it to one of the five ‘authorised locations’ within the exclusive economic zone (EEZ) and to scuttle (sink) it using explosives. The authorised location (dump site) proposed to be used is located 25 nautical miles (NM) southeast of Otago Harbour. The proposed activity falls under the definition of ‘dumping’ with the Exclusive Economic Zone and Continental Shelf (Environmental Effects) Act 2012 and requires a marine dumping consent from the Environmental Protection Authority (EPA). Considerable cleaning and preparation work will occur on the vessel prior to it being towed the dump site. This work will involve removing much of the salvageable material which will be taken onshore and either recycled or re-used. Material that is unable to be recycled or re-used will be disposed of to landfill or to facilities authorised to accept such material. In addition, contaminated water and fuel will be removed from the vessel and the tanks cleaned using Simple Green (a degreaser without harmful bleach or ammonia). The vessel contains some asbestos and this will be removed by specialist handlers and disposed of at a facility authorised to accept such material. Ash material from the fire will be put into the cleaned lower fuel tanks and encapsulated by cement which will be pumped into the tanks as ballast which is necessary to make the vessel safe for towing to the dump site. DWNZ will engage an independent recognised surveyor as published on the Maritime New Zealand (MNZ) website to approve the tow plan and to confirm the vessel is safe for the voyage to the dump site. This confirmation will be provided to MNZ in advance of the tow. The vessel will be scuttled using explosive charges. DWNZ has engaged explosive handing experts to plan and execute the scuttling plan. Four explosive charges are proposed to be placed at strategic positions on the inside of the hull and two very small charges will be fitted to the seacock valves – all the charges will be placed in the vessel, but not be armed, while the vessel is still at PrimePort, Timaru. A ‘Notice to Mariners’ will be issued by Land Information New Zealand (LINZ) to advise other marine users that the proposed activity will be taking place and this notice will also impose a temporary exclusion zone around the site, restricting other vessels coming near the towing and explosive operations. Page 3 DW New Zealand Limited SLR Ref No: 740.10102.00000-R01-v1.0.docx Marine Dumping Consent Application and Impact Assessment December 2019 Scuttling of Dong Won 701 Fishing Vessel Within an Authorised Location South-east of Otago Harbour EXECUTIVE SUMMARY Once in position at the dump site (being within 1 NM radius of 46°00′S 171°13′E, this being the centre of the dump site), the explosives experts will board the vessel using a small tender from the towing tug and arm the explosives, including fitting the detonator. Once armed, the explosives experts will disembark the vessel using the small tender and board the towing tug which will move 200 m directly off the bow of the vessel (which will still be connected under tension via the tow rope). Once it has been determined that no marine mammals have been detected within the specified mitigation zone (discussed below) the explosive experts will initiate the blast sequence. The first explosives that will detonate are the two very small charges on the seacock valves, followed by the four main charges, all with 25 ms delays. Detonation of the very small charges on the seacock valves will result in water slowly entering the vessel and the four main charges will result in blast holes just above the waterline. The vessel will initially sink slowly as water flows through the seacock valves and the vessel will be continue to be connected to the towing tug via the tow rope until water starts entering the blast holes, after which the tow rope will be released and rapid flooding of the vessel will occur, causing the it to sink rapidly. It is expected that the vessel will sink stern first and disappear under the water within 20 minutes of water entering the blast holes. Calculations have been undertaken to determine underwater noise effects based on the explosive charges that will be detonated. The calculated noise levels have been compared to known thresholds for the specific marine mammal species that could be in the area – these being thresholds that would prevent permanent injury to marine mammals. A 600 m mitigation zone has been established (based on the hearing sensitivities of the marine mammals that may be present) to ensure adverse effects on marine mammals are avoided to the greatest practicable degree. DWNZ will use a qualified marine mammal observer on the towing tug to observe whether there are any marine mammals within the 600 m mitigation zone - if any marine mammals are observed within the mitigation zone, then the detonation will not commence until the marine mammals have moved beyond the mitigation zone or the mitigation zone has been shown to be clear of marine mammals for 30 minutes. Once the vessel has filled with water it will sink very quickly through the water column (stern first) before landing on the seabed. This will result in the crushing of any benthic structures or organisms present in the area where it lands. However, the footprint of the vessel will occupy only a small area of seabed within the authorised dump site and, as such, these effects are assessed as being negligible. The proposed activity will have very short-term effects on any other marine vessels that may otherwise transit through, or close to, the dump site – these effects lasting a matter of hours while the vessel is being set up for scuttling. While the vessel is en-route to the dump site it will be like any other maritime vessel and the towing operations will be carried out in accordance with all maritime requirements (i.e. Maritime Rules Part 22: Collision Prevention). A fisheries assessment has been undertaken which shows that limited fishing occurs in and around the dump site. No trawling has taken place there over the past five years – presumably because the area is identified as an authorised dump site (shown as an Explosives Dumping Ground on the New Zealand Nautical Charts) and trawlers avoid the area. Based on the limited fishing activity over the past five years at the dump site and the fishing methods employed there, no adverse effects on commercial fishing activities due to the presence of the vessel on the seabed will occur. Page 4 DW New Zealand Limited SLR Ref No: 740.10102.00000-R01-v1.0.docx Marine Dumping Consent Application and Impact Assessment December 2019 Scuttling of Dong Won 701 Fishing Vessel Within an Authorised Location South-east of Otago Harbour CONTENTS 1 INTRODUCTION ..................................................................................................... 12 1.1 Background ..................................................................................................................... 12 1.2 Structure of this Application ........................................................................................... 14 2 LEGISLATIVE FRAMEWORK .................................................................................... 15 2.1 Exclusive Economic Zone and Continental Shelf (Environmental Effects) Act 2012 ...... 15 2.1.1 Introduction.................................................................................................................................................. 15 2.1.2 Section 20 Restrictions ................................................................................................................................