Project 3. Awatarariki Stream and Lagoon
Frequently Asked Questions
That silt traps installed to protect the lagoon in 1993 at a cost of $163,000 were not maintained by DOC, becoming overgrown with raupo and falling into disrepair is a further example of neglect. Sadly, the predictions in that report became a reality even sooner than anticipated by its author.
The small silt traps installed by DOC would have had little/no impact on the debris flows into the lagoon – this was just too large an event. Silt traps of several hectares are being investigated for a like event currently – a maintenance plan is being assessed as part of the Resource Consent process. The new silt traps in front of the lagoon will be rigorously maintained.
Maintenance contracts will be enforced to ensure that the efforts in restoration do not get destroyed. Contract reviews will be conducted to ensure the high standard expected is maintained.
There is no extra cost related to maintenance that has not already been published – all related maintenance costs are included in the LTCCP calculations.
That the Matata Residents Association made submissions relating to the cleaning of all streams which were not actioned.
Even if the steams were in pristine condition, unfortunately the level and significance of the May 2005 event would have seen these streams flooded and compromised.
As part of the resource consent process there is an opportunity to make “conditions” to resource consents. It is expected these conditions will include assessments and maintenance programmes to ensure stream integrity is kept intact.
That subdivision was allowed in an area where there was ample evidence of past events.
It could quite easily be argued that the majority of Matata currently resides on a debris flow fan of one age or another. The geological evidence is now self evident.
The aim of these mitigation works is to ensure that all properties in Matata are protected into the future.
Following perennial lobbying from Matata Residents and Ratepayers Assn., WDC commissioned a report on Matata Stormwater – Stream Investigation in June of 1999. This report documented the “URGENT WORKS” required and the steps necessary for its implementation. The result: inaction. The report shelved – no steam or waterway maintenance undertaken, wasting time, effort and ratepayers’ money – leaving the problems to escalate. Had that work been done, there may have been significantly less damage to Matata properties and homes on 18 May 2005.
Even if the streams were in pristine condition, unfortunately the level and significance of the event in May 2005 would have seen these steams flooded and compromised. The damage to Matata happened in a very short space of time – the steams capacity would have been breached irrespective of the report described above. This is the reason to ensure there is only a Q5 return period flow to be returned through Matata in the Waitepuru Stream. Waimea Stream is being upgraded to suit revised hydrological design flows.
Maintenance contracts will be enforced to ensure that the efforts in restoration do not get destroyed. Contract reviews will be conducted to ensure the high standard expected is maintained.
The Eastern Lagoon is visibly silting up through lack of water flow and fears are held that it, also, will be lost if action is not taken soon.
Work is being done in advance having recognised this issue. There are some workings being completed on a Resource Consent for ‘Preliminary Works’. Timing is yet to be established – but is far in advance of what was planned – as soon as this becomes better established – the Community will be informed.
A forum has been established by DOC that includes representation from the Matata community.
What monitoring and maintenance measures can the Community count on from WDC? The Community needs a transparent maintenance programme which the Community can monitor.
Agreed – see Resource Consent ‘Conditions’ – this will outline the expectations of the authorities in maintaining these streams.
Will WDC or one of their agents accept responsibility for clearing away items/materials capable of forming a blockage in storm conditions?
Per above – Resource Consent ‘Conditions’ – this will outline the expectations of the authorities in maintaining these streams. WDC will be one of the authorities maintaining these assets.
The Lagoons
Silt and debris have choked, or are building up in what were once beautiful lagoons and wildlife sanctuaries.
What protective measures are WDC prepared to instigate to ensure silting from the Awatarariki, Waimea and Waitepuru Streams do not undermine the restoration/rehabilitation work undertaken with the lagoons?
Silt traps per detailed design.
What protections will WDC install to minimise the risk of the lagoons again being swamped with silt and debris?
Debris dams and silt traps per detailed design.
Will provision be made for extreme flows from the Awatarariki to be directed away from the lagoons, either westward and/or out to sea?
No, but extreme flood flows have been modelled and the streams capacities will be designed to accommodate these flows.
Will the causeway be properly formed and sealed, as had been proposed, before May 2005, with parking and toilet facilities to the same standard as those at Ohope?
There is a vesting process currently being undertaken between WDC and DOC. It is envisaged that the upgrade of this causeway will happen in this financial year – there are also some works required to be carried out on the causeway culverts in the Matata Regeneration Project.
View other community questions with a focus on general issues.