To: Environment Canterbury Catchment Subcommittee
From: Ashley-Rakahuri Rivercare Group
Subject: Gravel mining/extraction
Key concern: Retaining the river in its natural state still has lower priority status than the considerations of commercial mining interests.
Applications for gravel mining have not kept up with recent and more informed management ideas and practices. There is a vacuum of expert environmental and mining knowledge being required and applied to the policy, rules, applications, consents and river operations. As a result, the care and protection of the natural river environment is only vaguely mentioned in consents, operations are being inadequately monitored, and adverse environmental outcomes have been overlooked.
While the picture of a loader and truck removing gravel from the riverbed may look benign, gravel mining is acknowledged internationally as a major threat to the existence of braided rivers, along with damming, and constrictions. Consequently, it has been banned in a number of countries.
The main Issues:
1.Gravel removal is not conducted in a sustainable way – how much gravel is there in the river?
To date we have not seen sufficient evidence to justify the extraction of half a million cubic metres of gravel – the sum of applications now before ECan.
The Ashley-Rakahuri is not regularly topped up with large quantities of gravel.
Some is added irregularly by flooding and natural eroding of banks, but this has been reduced significantly by tree planting on the berms.
Crucially, for the health of the river, accurate data on the amount of gravel must be kept for gravel to be removed at a sustainable rate.
Before the May flood of 2021 ECan halted gravel takes, yet these have restarted even while opinions differ on whether there is enough gravel available.
An ECan report states: “The Ashley has a relatively low estimated annual supply of gravel … from the foothills. Volumes extracted are not replenished at the same rate.”
We submit that gravel mining should not proceed until more accurate information is available relative to gravel reserves currently existing in the riverbed
2. The application and consent process
To prevent destruction of the river environment a significant application and consent process around site characteristics and cumulative impacts is required.
All gravel mining consent applications must include an operational manager with the required (and current) Quarry Manager’s qualification.
At present, applications are filled out by consultants who know how to tick the boxes. There is no demonstrated knowledge of appropriate braided river management and history, or of consultation with important stakeholders such as the Ashley-Rakahuri Rivercare Group.
Detailed specifications of each mining site should be required in applications, along with operational intentions for each.
Operational criteria for the protection of the natural river environment should be written in all consents.
We submit that any gravel mining application must involve on-site management with a current Quarry Manager’s qualification, and that indigenous river habitat be safeguarded by best practice intentions which are clearly stated in all applications.
3. What happens during gravel mining?
Removal of gravel often leads to:
- creation of fast-flowing single channels, often with steep banks which prevent young birds from accessing water/shingle interfaces
- shallow braids, essential for bird feeding, are lost
- island height is reduced, making bird nests more vulnerable to any rise in water levels
- flow around islands is cut off allowing access for predators.
- easy vehicle access is created, opening up opportunities for human disturbance
Our studies show there are five to six times the number of birds nesting in braided areas compared with other ‘single channel’ parts of the river.
We submit that consents contain a description of the braided state in which mined areas should be left once mining is completed.
4. Supervision / monitoring
When a consent is granted, there are few restrictions. Companies tend to mine in whatever way likely to prove most cost-effective for them. Environmental consequences are not adequately prioritised and catered for.
As mentioned, this can be remedied by a more in-depth application and consent process, accompanied by regular supervision, monitoring and, if necessary, policing to ensure adherence to consent criteria.
It would be prudent to appoint an on-river gravel ranger, with a background in the environmental sciences/mining to advise and monitor.
We submit that proper compliance procedures be included in all consents, and that these be appropriately implemented.
Large gravel trucks with trailers on public land can be a danger to walkers, cyclists and trappers, particularly along access roads into the river. Points where stopbanks are crossed are notable high hazard sites. More signage and efforts to alert the public to truck movements is essential.
Truck routes to gravel sites should be chosen so that the negative impacts of dust / noise are avoided / minimised, particularly close to housing and recreation areas.
We submit that safety aspects are given greater attention in consent applications.
Any company applying should have a clean record with ECan.
We submit that the operational history of gravel mining applicants be taken into account in any consent approval procedure.
6. Stakeholder consultation creating ‘win-win’ associations
Some gravel companies have worked with us to rehabilitate their mine sites. We are grateful for their consultation and cooperation. The end result has been the maintenance of good habitats for bird feeding and breeding. However, this has not been the case with other gravel miners. As outlined above, the desired environmental outcomes from all gravel mining operations will only be assured by well-informed environmentally aware management plans.
We submit that all gravel mining consents on the Ashley-Rakahuri River require consultation with key river stakeholders such as ARRG.
For the survival of the Ashley-Rakahuri River in its natural form, there is an urgent need for ECan to prioritise environmentally based decision-making when considering gravel mining within the river. In order for this to occur, professionals trained in the environmental sciences and best practice mining should be at the helm and oversee the whole process.
We submit that there is need for a complete overhaul of the gravel mining consenting and operational procedure within the Ashley-Rakahuri River.