Answers to questions
Will the Dome Valley landfill be the biggest in NZ? How many tonnes of rubbish will be delivered annually to the landfill? What is the tonnage capacity of the 60ha landfill? How high will the walls of this first landfill be?
The proposed landfill will be situated in one of the valleys on the site. The valley itself will form the landfill. The annual tonnes of waste received depends on a number of factors. This includes how much waste is produced by the community that cannot be re-used or recycled.
Auckland Council has forecast in their Waste Management and Minimisation Plan in 2018 that approximately 1.6 million tonnes of waste per year will be produced by the community. We expect the Auckland Regional Landfill (ARL) would receive less than 50% of this as some waste will be disposed at Whitford Landfill and Hampton Downs Landfill in the Waikato.
The landfill's leachate barrier liner will not last longer than 100 years and that's an unacceptable environmental risk - comment?
This is not correct.
In a landfill, there is a lining system installed at the base of the landfill, not a single liner. This system provides a barrier to prevent seepage of any contamination into the surrounding environment and groundwater.
The lining system proposed for ARL has three main components. These are a compacted clay or mudstone liner of 600 mm minimum thickness, overlain by a Geosynthetic Clay Liner (GCL), which then has a fully welded continuous 1.5 mm thick High Density Polyethylene (HDPE) liner on top. The clay liner is a naturally occurring material. The GCL liner is made from bentonite, which
is similarly naturally occurring. Both have been around for thousands of years. The HDPE is a man-made material with an estimated life of 400 – 750 years. By this time, the landfill will no longer be producing leachate that poses an environmental risk.
Above the HDPE liner are two liner protection layers, which would protect the HDPE from any physical damage. These include a geotextile cushion layer and the 300mm thick stone layer (leachate drainage layer).
The landfill discharge leachate - heavy metals/chemicals will run into the Hoteo River and out into Kaipara Harbour bringing a permanent negative environmental impact - comment?
This is not correct.
The waste from the landfill will be fully contained by a purpose designed and constructed landfill lining system. The lining system protects the surrounding environment and groundwater from contamination from leachate.
The leachate is collected in pipes and extracted from the landfill on an ongoing basis and treated. Leachate is not stored in the landfill and leachate will not be discharged into streams.
The selected lining system is designed to provide physical containment for hundreds of years after the landfill stops receiving waste, by which time the landfill will not be producing leachate that poses a risk to the environment.
Developing the landfill will create sediment runoff into the harbour in the same way as .6 - comment?
The area covered by the proposed landfill footprint only represents approximately 0.14% of the catchment for the Hoteo River and 0.0091% of the Kaipara Harbour catchment.
During construction and operation of the landfill, best practice stormwater management techniques will be used to mitigate potential environmental effects on the surrounding environment.
We will constantly monitor the water quality and sediment loadings of stormwater, starting well before any construction and continuing throughout the life of the landfill and aftercare.
We will be required to report the results regularly to Auckland Council.
Any stormwater from areas that we will not disturb upstream of the landfill will be diverted around the waste and areas in which we will need to work.
In addition, downstream of the landfill we will build a series of stormwater management ponds (dams) and wetlands. These will be designed to remove sediment and filter the water before it is released to streams within the site, which will then merge with other streams and eventually flow into the Hoteo River (approximately 3km away from the end of the landfill) and on to the Kaipara Harbour, approximately 30km away.
KDC is strongly against the landfill and says it should not go ahead - comment?
The Auckland Council area currently includes two modern operating landfill facilities for waste disposal – Redvale Landfill and Energy Park in the north and Whitford Landfill in the south-east. Redvale is expected to be full in 2026-2028 and Whitford is consented until 2040, but has restrictions on the amount of waste it can receive.
Auckland Council’s Waste Management and Minimisation Plan projects that the region's annual waste amounts will continue to grow through to 2060. Auckland and the wider region will need an environmentally safe and secure site for disposal of this waste. The proposed landfill, if approved, is designed to meet this need.
What message would you have for Northlanders who are increasingly concerned about the proposed landfill?
We understand that people may have concerns and questions and we have been engaging with the community since October 2018 on this project.
We continue to encourage anyone with concerns to contact us so we can listen to their concerns and discuss the proposal in detail. We will also be reviewing all submissions received through the consent and plan change processes and will be addressing any concerns raised through these processes.
We want to reassure the community that Waste Management has designed, constructed and operated Class 1 landfills throughout New Zealand for more than 25 years, including Redvale and Whitford Landfill and Energy Parks in Auckland and Kate Valley Landfill and Energy Park in Canterbury. These facilities are designed and operated in a manner that protects the environment from potential adverse effects from the waste that is produced by all New Zealanders.
Waste Management operates all three of these landfills to the highest environmental standards and this landfill will be to at least the same or better standard.