Flood recovery – FAQs
We are collating responses to the most frequently asked questions on the recent flood recovery work done by us. More FAQs will be added as responses become available – and responses may be modified in light of any new information or advice received.
Updated 9 July 2021
There are a number of farms that have suffered damage to farm infrastructure, preventing them from achieving their normal levels of compliance. This includes damage to effluent ponds and loss of fencing along waterways. We understand that it may take some time for farmers to reinstate this infrastructure, and that this will vary on a case-by-case basis.
Our expectation is that farmers will develop a plan to restore the functionality of damaged infrastructure when practicable to do so and that efforts are made to minimise any environmental damage in the interim. For example, this may involve the use of temporary fencing as an interim measure before permanent fences can be installed. What is considered practical and appropriate mitigation will vary from farm to farm.
With regards to environmental compliance, we always consider these questions on a case-by-case basis.
So, while we don’t offer blanket extensions or exemptions – we would recommend that any farmers struggling to meet compliance requirements due to damaged infrastructure contact our Zone teams. Staff will confirm agreements made around for timeframes for compliance. This will provide some surety to the landowner, and also allows Environment Canterbury to address any questions which might be raised by the public. Your local contacts are:
Canterbury recently experienced extreme flooding in some inland areas that NIWA states might only be expected to happen once in 200 years.
This was an unprecedented weather event with both long and intense periods of rainfall. In the Ashburton River/Hakatere catchment area the weather event was of a magnitude greater than everywhere else in the region. We cannot stress enough that this was potentially the most significant rainfall and river flow event on record in Ashburton since we’ve been recording this data.
The Mount Somers rain gauge recorded the most intense rainfall, with 546 mm recorded for the 72-hour event. This is more than double the previously recorded maximum for 72 hours. Fifteen of our eighty-four water level recorder sites reported their largest flood on record.
Environment Canterbury’s current mandate from Council is to maintain flood protection assets for properties who form a rating district. This includes protection works such as stopbanks, drains, groynes, spurs and other infrastructure such as plantings associated with river erosion, drainage and flood protection as well as ongoing maintenance.
We manage 59 river and drainage rating districts and in the 25 largest areas, we work with the community who voluntarily participate in river rating district liaison committees.
Committee members focus on whether their community has an adequate and appropriate level of safety, security and resilience from flooding and erosion, or an adequate and appropriately resourced drainage network. Each rating district has agreed levels of service, which means that flood protection infrastructure is built and maintained to withstand a specific discharge of flood flow measured in cumecs (cubic metres of water per second) and/or they carry out a particular activity e.g. planting or weed control. Flood protection schemes are designed as holistic systems that may have different levels of service throughout. For example, stopbanks in the upper Ashburton scheme are built to manage about a 1 in 50 year flood and stopbanks closer to the town have higher levels of protection to about a 1 in 200 year standard.
Committee members are advisory to Council who make final decisions. Members can influence the overall direction of flood and erosion protection and drainage works in their area as well as the targeted rates set for each river. The decision about what level of protection can be provided is balanced against a sustainable level of financial contribution from the community for the works required. Targeted rates are the amounts contributed to the total cost of works by the landowners who receive the direct benefit of flood protection infrastructure. They are based on the cost of works to provide the agreed level of service and calculated as a percentage of their property value.
If due to a significant weather event, flood flows exceeded the capacity that the infrastructure is designed for, out-of-river flows are expected. For the upper Ashburton River/Hakatere the event was ‘over design’ meaning it was much larger than the flood protection infrastructure was designed to contain.
Removal of rocks/gravel from any property post flooding is currently not part of our mandate. From time-to-time Environment Canterbury staff might undertake work on private land where this assists in delivering the objectives of the rating district (e.g. where the removal of debris, trees, gravels etc. forms part of work required to meet flood protection objectives within the rating district). However, this work is typically limited in scope.
If the Council wished to undertake or fund significant work outside the agreed work programme for a rating district – such as removal of gravel from a property following a flood, this would require a specific Council decision and appropriation. Given the recent flood event and the expectation of more frequent and higher intensity floods due to climate change, landowners in some areas without any flood protection may now want to talk to us about the options for future flood mitigation.
Due to its geomorphology with a steep grade terminating on a flat plain, the North Branch of the Ashburton River/Hakatere has a very high sediment deposition rate compared to other rivers in the region. Specifically, there is a 14km ‘aggradation zone’ known as Blands Reach, between Flemings Rd and Mt Harding Creek.
Between 1997 and 2008, over 1 million cubic metres of gravel was extracted. Ongoing extraction of around 60,000 cubic metres of gravel per year is required to maintain the flood capacity in the aggradation zone. Gravel extraction averaging 38,000m³/yr in the 2009–2018 period did not keep up with the estimated natural supply rate of 60,000m³/yr.
In July 2019, the Ashburton River/Hakatere liaison committee resolved to put $100,000 per year towards enabling 100,000m³/yr of gravel to be removed from aggrading areas, concentrating initially around Shearers Crossing. This was reinforced in the 2020 meeting. 74,000m³ was extracted in 2020, the only full year since the target was introduced.
It has been very challenging to generate sufficient commercial gravel extraction through Blands Reach to keep up with the aggradation. Additional measures have been put in place to encourage gravel take in the North Branch including waiving the gravel extraction fee. It should be noted however that the primary cost of gravel is for haulage and so other closer sources were often prioritised by contractors.
The cost of simply removing and stockpiling this volume of gravel from the river would be significant – in the order of $300,000 per year plus land costs, or half the budget of the entire Ashburton River/Hakatere rating district. Environment Canterbury is in the process of identifying a suitable location to deposit proactively excavated gravel once it has been taken out of the river.
Prior to the flood (and still current) a total of 102,500 m³ of gravel had been allocated to contractors for take around Shearer’s Crossing (free of charge).
61,000 m³ is allocated for take from Thompsons Track towards downstream to Shearer’s. Further applications are in process but are on hold, awaiting repair works.
We understand that this will be a stressful time heading into winter with expectations of increased rain and snowfall.
In the first instance, keep an eye on the severe weather outlook from MetService.
As always, our flood controllers are on duty 24/7 and remain in close contact with MetService, especially given the vulnerability of our flood protection schemes. Our infrastructure is more vulnerable in certain places, and we’ve also lowered the trigger level at which we will issue alerts on those more vulnerable schemes.
If we are alerted by MetService to the possibility of out-of-river flows, we will post information on our flood warnings page and use our social media channels and the text alert system for proactive messaging into affected communities if required.
Our current focus remains keeping water in the river and ensuring lifeline infrastructure, such as roads can reopen.
Temporary fixes to flood infrastructure are being made where possible to reduce the risk of reoccurrence until permanent repairs are possible.
Some repairs can’t be done until the ground dries out, this might be closer to summer.
In Ashburton in particular, the recovery will take many months, possibly years to complete repairs.
Staff remain out in the field completing damage assessments. We are responsible for more than 2000 km of rivers (including 1601 km of managed river berm and 647 km of stopbanks) and 671 km of drains within flooding and erosion control and land drainage scheme areas, so following a major regionwide flood event like this it’s a big job.
We have mapped the majority of the known damage and are responding on a priority basis, including based on risk to people, property and infrastructure. We are re-prioritising our work on a daily basis based on these assessments.
The recovery to this event will require us to adjust work programmes and budgets. Additional resources will be required to restore critical infrastructure as well as deliver already agreed programmes of work.
We need to analyse the full extent of the damage and develop an appropriate work plan so we can’t quantify a timeline or repair costs just yet.
We are working on the next steps and will keep you updated.
It’s worth noting that we are also considering climate change and potentially modifying our recovery work in response rather than simply reinstating infrastructure as it was. In the Orari floods of 2017, rather than reinstate a stopbank we modified the design by building a new part of a stopbank further back from the river. During the recent flood event the modified design helped prevent breakouts that would otherwise have affected large parts of the community.
Currently, Environment Canterbury has a mandate from Council to maintain flood protection assets for properties who form a rating district and does not have the mandate to remove rocks/gravel from any property post flooding.
From time to time Environment Canterbury staff might undertake work on private land where this assists in delivering to needs of the rating district (e.g. where the removal of debris, trees, gravels etc. forms part of work required to meet wider flood protection objectives within the rating district). However, this work is typically limited in scope.
If the Council wished to undertake or fund significant work outside the agreed work programme for a rating district – such as removal of gravel from a property following a flood, this would require a specific Council decision and appropriation.
If a landowner is not in a designated scheme area, our engineers can assist with advice.
If requested by the community, we can also look at more comprehensive mitigation options through potential new management schemes. We would expect that landowners in some areas may now want to form a river rating district, especially as we expect to see more intense and frequent weather events as a result of climate change.
We are pleased to see that the Ministry for Primary Industries has implemented the Canterbury Flood Recovery Fund as a contribution towards urgent and immediate recovery work that could help to remediate shingle deposited on farms as a result of the recent floods.
We are prioritizing meetings with current River Rating District Liaison Committees first. Wider public meetings can be considered in time if needed. As staff are responding to priority issues on the ground, we can’t give a timeframe for any meetings at this stage. If you aren’t in a designated scheme area, our engineers can assist with advice. There is currently a high demand for advice from our river engineers, so visits are being prioritized with a focus on restoring the functionality of schemes that provide protection to multiple properties. A number of these visits have already taken place.
Environment Canterbury can offer flood protection advice to landowners outside of rating districts where we have staff capacity. Landowners should contact our customer services team in the first instance on 0800 324 636 to lodge their requests for visits. We will keep in touch with you as to when we can arrange a visit.
If requested by the community, we can also discuss the options for more comprehensive flood mitigation options going forward.
We are very mindful of the pressure some in our community are under, and we are keeping in close contact with all agencies involved in the recovery to best support everyone in our communities. The Rural Support Trust is the lead agency supporting households under pressure, and we will continue to work closely with them throughout the recovery.
When we are aware that a household is affected by pressures such as flooding, health or mental wellbeing, we have a range of options to alter our regulatory approach.
Find out more about what support is available for farmers to help respond to the region's flood.
At this time, Environment Canterbury has not made funding available for the removal of rocks/gravel from private property.
Currently, Environment Canterbury has a mandate from Council to maintain flood protection assets for properties who form a rating district. This does not extend to undertaking works on adjoining private land.
From time to time, Environment Canterbury staff might undertake work on private land where this assists in delivering to the needs of the rating district (e.g. where the removal of debris, trees, gravels etc. forms part of the work required to meet wider flood protection objectives within the rating district). However, such work is typically of limited scope.
If the Council wished to undertake or fund significant work outside the agreed work programme for a rating district, this would require a specific Council decision and appropriation.
Each rating district has agreed levels of service and the committees focus on whether their community has an adequate and appropriate level of safety, security and resilience from flooding and erosion, or an adequate and appropriately resourced drainage network, which is balanced against a sustainable level of financial contribution from the community.
We are confident that our flood protection infrastructure did its job based on this criteria, and cannot accept allegations of mismanagement or any responsibility.
This was an unprecedented weather event with both long and intense periods of rainfall. In the Ashburton River/Hakatere catchment area the weather event was of a magnitude greater than everywhere else in the region. We cannot stress enough that this was potentially the most significant rainfall and river flow event on record in Canterbury since we’ve been recording this data.
For the upper Ashburton River/Hakatere the event was ‘over design’ meaning it was much larger than the flood protection infrastructure was designed to contain. In this catchment out-of-river flows would have occurred irrespective of issues such as gravel aggradation.
The stopbanks on either side of the Ashburton River/Hakatere built a decade ago at a cost of a couple of million dollars proved their worth, protecting assets worth hundreds of millions of dollars and prevented many homes from flooding.
The flood protection scheme is designed as a holistic system and has different levels of service throughout it.
For example, stopbanks in the upper scheme are to a 1 in 50 year standard and stopbanks closer to the town are to a 1 in 200 year standard. Braided rivers are dynamic in nature and where water breaks out is not always predictable.
It is likely that water spilling out in the upper reaches took some pressure off in the lower reaches but we have not quantified that yet as our current priority is physical works on the ground to help protect the community from further flooding.
We are prioritizing meetings with current River Rating District Liaison Committees first. Wider public meetings can be considered in time if needed. As staff are busy responding to issues on the ground, we can’t give a timeframe for any meetings at this stage.
If requested by the community, we can look at the potential for mitigation options through new management schemes. We would expect that landowners in some areas may now want to form a river rating district, especially as we expect to see more intense and frequent weather events as a result of climate change.
We understand the flooding has caused significant additional stress to some consent holders who still have consent reviews in process, and that understandably their consent review is not their top priority currently.
We’ve offered a three-month extension to consent holders affected by the floods whose reviews are still in process for them to evaluate their position.
We also understand that some consent holders will require further extensions beyond the 30 November 2021 cutoff date.
We can only offer extensions to those who have requested it. If you would like an initial three-month extension of your consent review, please contact firstname.lastname@example.org.
Testing is the responsibility of private well owners.
For additional information, read more on Canterbury's drinking water, or download our resource on private well safety (PDF File, 172.52KB).
In 2019 we wrote to Ashburton residents who rely on private wells for drinking water (outside of district council water schemes) about the need to test their wells/maintain their wellheads. You can find the letter under Protecting your private drinking water source.
Flood response text alerts indicating likelihood of out-of-river flows.
The free subscription-based text alerts are activated during an emergency flood response. You can sign up to receive alerts for specific rivers by texting a keyword (we use river names) to 3730. We publish a list of the keywords on our website in the lead-up to a flood event. By signing up to this service your number is added to a database that our flood control team will use to send messages to you about river conditions in current and future flood events.
Texts are sent on an as-needed basis. The alerts let you know that river flows on a specific river are approaching levels that could cause out of river flooding so that you can take informed action.
Note that we do not send evacuation notices through this service, as this is a function managed by Civil Defence Emergency Management.
During the recent flood event, text alerts were sent to the Selwyn, Ashburton, Hinds and Waimakariri subscriber lists in response to rising flows on those rivers.
If no alerts are sent to a list that you have signed up to, this means that the river flow information we have does not indicate out-of-river flooding is likely.
When you initially text the keyword (e.g. ASHBURTON) to 3730 and you’ll receive this note:
- Thanks for subscribing to ECan’s Ashburton River flow alert service.
Note that any responses sent to this system are not monitored and you will not receive a reply – they are only for oneway communication. This means that if you return a message to the above text (or send any message that does not correspond exactly to the keyword) to 3730 you will receive this message:
- [NO REPLY] This service is used for outward communication only.
This reply may also have been sent if the system malfunctioned. If you are concerned that the system did not function as designed, please assist us by sending customer services a screenshot of the text that you sent and the text that you received. There is no indication that the system malfunctioned during the recent weather event.
Riverflow text information
Text alerts per the river flow pages send a one-time text with the latest flow data available for that river to your phone.