Water News May 2014
River water could cause price rises for fruit and veges
5 May 2014 – Waikato Times
Prices for fruit and vegetables and the resilience of the country's food supply will be affected if Auckland Council's application for more water from the Waikato River is successful, New Zealand's horticulture industry body says. Horticulture New Zealand, which represents the country's fruit and vegetable growers, is worried growers in the Pukekohe and Pukekawa regions could feel the effect of Watercare's application to take 200,000 cubic metres of water a day from the river.
Auckland's population is expected to grow by at least 800,000 people by 2049 - exceeding the city's current supply capabilities - and the Waikato River has been identified as the preferred source of water to meet demand.
Farmers have already voiced concern about the application and the proposal has highlighted the pressures on Waikato's finite water supply.
Chris Keenan, the natural resources and environment manager at Horticulture New Zealand said if approved the proposal would cause some smaller operators to "go to the wall".
"I think it would definitely affect supply and affect the resilience of food security."
Watercare already takes 150,000 cubic metres of water a day from the river, but the additional take would mean the "allocable flow" of the lower river catchment would be exceeded.
At low flow times users get asked to draw back on water to ensure the minimum flow is maintained.
But under the variation 6 of the regional plan, supply to Auckland would be prioritised during periods of low summer flow and, as a public supplier, when applications are made.
Keenan said security of supply for growers would be compromised.
"If you don't have the reliability of around nine years in 10, that will significantly affect your gross margins or your profits."
The Government has set targets to phase out over-allocation of water in catchments by 2030.
If Waikato Regional Council approved the application, Keenan said, it could mean growers in Pukekohe and Pukekawa would have to cut back surface water takes by as much as 60 per cent.
"Water is being allocated for the domestic and municipal needs of an additional 800,000 Aucklanders.
"They will also need food, but no provision has been made for growth in food production."
Council spokesperson Stephen Ward said if there was over-allocation in any catchment in the future, it would need to be addressed.
However, he said the council's consenting team had made no mention of 60 per cent cutback to growers.
"We would hope efficiency of use gains could best address this over allocation before cutbacks to existing users."
The Pukekohe Vegetable Growers Association, which represents north Waikato growers, estimated there were between 2500 to 3000 people directly employed by horticulture in the Pukekohe/Pukekawa region.
Keenan said the two areas were inseparable when it came to production and relied on each other for "critical mass".
"The loss of our ability to water this land will never be recovered elsewhere.
"The regions of Pukekohe and Pukekawa are unique across the country."
Ward said Watercare's application was still being processed it would be premature to speculate on its outcomes.
Plan for water shortage
14 May 2014 – Waikato Times
Increasing demand for water will force us to change how we use the resource.
However, steps need to be put in place to manage it better, according to Waikato University environmental planning professor Iain White.
White attended a forum on water use in Hamilton called Water Sensitive Cities and said a long-term strategy needed to be put in place before it was too late.
"The need for some more strategic thinking about the resources in Hamilton, not just over five years but over 20 years," he said.
A panel of experts attended the forum at Te Runanga O Kirikiriroa offices yesterday.
White said there was a healthy debate among about 30 people who were there, as well as a broad consensus.
White said public and private organisations tended to work in silos but needed to come together on water management to get the best outcome.
"We've got a very unsophisticated view of how we manage water," he said.
Floods still threaten Nelson farms
14 May 2014 – Nelson Mail
Frustrated farmers on low-lying land near Nelson city fear that their livelihoods are at risk from bureaucratic delays to flood protection work.
Several farmers from the Glen and Wakapuaka made a plea for help at the Nelson City Council annual plan hearings yesterday, outlining the extensive damage to their properties from the 2011 floods and their fears of further damage if drainage work is not done.
Water from the Glen, Wakapuaka's Hillwood Stream and Todd Valley catchment areas flows through drains across the farmers' land out to sea, but the drains need to be cleaned regularly to keep the water flowing.
Warwick King, Les Hollyman, Jan Gillanders and Andrew Newton told councillors their farms were hit hard by the December 2011 floods. King and Hollyman said they lost around $250,000.
Newton said that although the flood was an exceptional event, having the drains cleaned out would have helped to limit the damage.
King and Hollyman spoke of the "massive amount of trauma" they faced in the floods' aftermath. Hollyman had to move his grazing stock to Canterbury, eventually selling it at a loss.
Gillanders said the drains had been neglected before the floods and were still not up to standard.
She said farmers were worried that if something was not done to clear the drains and create better infrastructure, they could face more flooding and further stress.
A 40-year-old fund set up under the former Wakapuaka Drainage Board paid for drainage work in the area, with contributions from rates in the Glen area. Farmers previously used the money to hire a contractor to clean the drains.
The council later took over the fund's administration and allocated about $5000 to $6000 for a contractor to carry out the cleaning work.
Last year the farmers said they were sanctioned by council staff to contract someone to do the maintenance work. Once it was under way, however, they were visited by a council officer who threatened them with prosecution unless they stopped the work, as the hand-dug drains were now considered natural waterways and needed resource consent.
The farmers said nothing had been done since then.
"[The council] took over responsibility of the drains, and they were going to issue themselves a resource consent to do the job, and then they have not done it," Hollyman said.
Hollyman told council chief executive Clare Hadley yesterday that there were problems with how council staff communicated.
He asked if the council was going to foot the bill if his land suffered more flood damage because of the poor infrastructure.
The farmers asked what they were getting for their rates. Hollyman said he paid approximately $30,000 a year for two rural properties, but on his and Gillanders' land in the Wakapuaka area there were no dwellings, sewerage, rubbish collection, or household water connections.
Gillanders said the farmers felt marginalised by the council, as the rates had not come back to them by supporting infrastructure running into their land.
The farmers said that when their land was healthy and green, it was a beautiful asset to the region, but it needed the infrastructure to support it.
Nelson Mayor Rachel Reese said she understood the trauma the farmers had been through with the December 2011 floods.
"What their submission highlights is that good flood protection is really important not just for people living in residential areas, but also our people running businesses on rural land and for our farming community."
Reese said investments had been made in the Wakapuaka area by the Cawthron Institute and other organisations as part of the Glen agriculture development, so it was important to ensure that there was appropriate flood protection for the area.
A council spokeswoman said today the council recognised the special nature of the Wakapuaka flats and the area's historical issues.
She said there had been a misunderstanding with a landowner last year about which sections of a drain were to be cleaned, "resulting in work being carried out on council property without a resource consent. We are now in the process of obtaining the necessary consents for clearing all drains on these flats".
The council also had spending identified in the next Long Term Plan for an investigation into a more enduring option for stormwater disposal from the whole Wakapuaka flats area, she said.
Flooding bill facing wave of objections
15 May 2014 – Waikato Times
Tairua residents are baulking at regional council plans to spend $600,000 on flood protection work and directly charge them for 75 per cent of the cost.
They want the work, at Grahams Creek in Ocean Beach Rd, to be done but they don't like the way the council proposes to fund it.
A tenth of the cost would come from the general rate, 15 per cent from a targeted Coromandel Peninsula rate and the rest from the properties that benefit from the works.
The area has flooded many times over the years, the last time in December.
Tairua residents were out in force during the regional council's hearing on its Draft Annual Plan for 2014/15.
The plan confirms a commitment in the 2012-2022 Long Term Plan to the $600,000 floodway improvement, conditional on Thames-Coromandel District Council upgrading Manaia Rd causeway bridge and a landowner giving access where flood improvements will take place.
Gerald Ruys of Tairua thought those in the affected area should not be expected to pay extra rates as they were the ones at a disadvantage.
"I do not think it is right for WRC to class this as ‘user-pays policy', classing these ratepayers as living in the area of benefit, instead we consider these residents to be living in the area of disadvantage.
"As flood victims they have suffered damage to their properties, and most likely a devaluation of their properties through no fault of their own."
This was a case of disadvantaging the disadvantaged, he said.
"I do not think it is fair for them to be expected to pay $600,000 of a target rate as a condition for getting the essential services that they need.
"Ratepayers have a right to expect these services to be provided by the council in return of the annual rates and levies."
Ken Tanner of Tairua was also against the targeted rate.
"Property owners should not be considered beneficiaries when they receive no benefit."
Derek Boyd had no objection to the targeted rate but thought every ratepayer in Tairua should pay, rather than just the surrounding property owners.
He said sharing the cost would make it fair for all, as he believed all property owners would benefit from the improvement.
Joyce Birdsall, who owns a property in Tairua that is not included in the targeted rate, said she would be happy to contribute to the cost and thought all of Tairua should be included in paying for the upgrade.
Brownlee: Quakes didn't cause floods
15 May 2014 – The Press
Earthquake Recovery Minister Gerry Brownlee has asked for the addresses of flood-prone homes in Christchurch, but says he is still waiting to receive them.
The request comes at a time when he is casting doubt on whether it is up to the Government to fork out for those affected by the floods.
The city council has told residents to prepare themselves for a bleak winter after a flooding task force said solutions were unlikely to be in place this year.
Brownlee has now questioned whether the many recent flooding events are linked to the earthquakes, adding that the responsibility for repairing the damage, lies with the city council.
"The flooding is perhaps exacerbated by the earthquakes but not entirely caused by the earthquakes and so the responsibility lies with the council," Brownlee said on Radio New Zealand this morning.
Brownlee said the Government wanted to help Christchurch. The prime minister was in the city on March 5 and "said to the mayor, 'We will do what we can to help you. Tell us what you need'."
"We're still waiting. It's very frustrating."
EQC CONSULTANT: QUAKES INCREASED NUMBER OF FLOOD-PRONE HOMES
Earthquake Commission consultants say the quakes have increased vulnerability to flooding as a result of the .
Tonkin and Taylor, speaking yesterday at the three-day Stormwater 2014 conference, said modelling had identified thousands of properties where the land had dropped or risen up.
Each property would be visited.
The modelling had been peer reviewed but was subject to potential legal challenges.
Flood-prone home number already doubled
15 May 2014 – The Press
The number of flood-prone homes known to the council has doubled since Monday.
On Monday the Christchurch City Council released flooding ''vulnerability categories'' which identified:
- 56 homes had flooded above floor levels twice or more.
- 451 homes had suffered flooding below floor level more than twice.
- 487 homes had access compromised by flooding more than twice.
However the head of the council flooding taskforce today admitted the data was already "significantly" out of date.
Land drainage operations manager Mike Gillooly told the Stormwater 2014 conference that more homeowners had contacted the council to say "hey, you left me out".
Not only had the flood-prone numbers doubled, it was doubling "in areas where I didn't realise we had flooding".
"One of the key things about flooding is not everyone rings up and says I'm flooded you better come and have a look. They deal with it themselves,'' said Gillooly.
When assessing the ''vulnerability categories'', the taskforce visited areas which had reported flooding, he said.
''We couldn't look everywhere so we had to look at certain places where we knew flooding was most prevalent."
In particular, these were the places which flooded in March, April and May this year, but also in August 2012 and June 2013.
''We've had a lot of flooding but we have also had a lot of rain,'' he said.
Gillooly said the situation was unacceptable in a ''first-world'' country.
''Being flooded once is an insult. But it is an absolute travesty to be flooded more than once in a first-world country,'' he said.
He told the conference that ''complacency'' had played a part in the flooding.
'' . . .one of the things about Christchurch in the past 10 or 15 years, is that land drainage and surface water has been the poor orphan to the other two waters - water supply and waste water - and we led ourselves down a path of complacent thinking where everything would be OK when clearly it is not,'' Gillooly said.
Solutions were needed quickly, with reports of increased respiratory problems and mental illness, he told the conference.
Christchurch flood action in legal limbo
17 May 2014 – The Press
The Earthquake Commission (EQC) wants to determine how much flood-prone Christchurch properties have dropped in value and settle claims for that amount.
However, whether the money is given to homeowners or used to help pay for area-wide mitigation will be decided by Earthquake Recovery Minister Gerry Brownlee and the outcome of a High Court judgment.
Computer-generated modelling of land and river systems across the city has identified about 9000 properties that may fall into the increased flooding vulnerability (IFV) land damage category.
EQC head of land settlement Zac Berry said there were two options for settling these claims - one would leave the homeowner out of pocket and with uninsured land, and the other would compensate homeowners for the loss of value to their properties because of increased flood risk.
The preferred option is using a loss of value system but because this form of settlement has never been tested, EQC has asked the High Court to rule on whether it is legal.
Berry said the next phase would involve "ground truthing", where engineers would physically inspect the damage. Once this was completed, EQC was expecting closer to 7000 properties to be in the IFV category.
Land could not be remediated on a property-to-property basis because raising one person's land would only create more trouble for surrounding homeowners, he said.
The preferred settlement option being explored would result in homeowners being compensated for the loss in value of both their land and dwellings.
Berry said that if a house was worth $400,000 before the earthquakes and was now valued at $350,000, the claim would be settled for $50,000.
He hoped the court case would deliver a "favourable outcome" by the end of August but admitted claims could not be resolved if there were any delays.
"This is where we get to the point where . . . we will look to central and local government for direction.
"I don't want to use terms like ‘lap of the gods' but ultimately there are some external factors that will give us direction of just how that will play out."
Engineers have been told to prioritise the Flockton Basin for physical inspection and all claimants in the IFV category will receive letters detailing the next steps by early June.
Repairs to 309 homes now in the IFV category are on hold and customers have been given the option of having their property repaired ahead of confirmation of their land damage, receiving a cash settlement or remaining on hold until land damage is confirmed.
EQC did not have figures on how many properties in the IFV category had already been repaired.
"Without doubt there will be properties that have been repaired that are now going to find themselves in this category," Berry said.
Brownlee said EQC would contribute to an area-wide fix in areas such as the Flockton Basin but said the total amount might not be "anywhere near as significant as some would like".
"But that court case is important because it sets the precedent going forward," he said.
Brownlee was angry the council had still not approached the Government with a mitigation proposal.
"I can't believe it's been eight or nine weeks since they said they would come to us with a proposal," he said.
"I'm sick of it, to be honest."
A council spokesman said yesterday the proposals would be discussed with the Government after being considered at a council committee meeting on June 5.
Carrick St homeowner and spokeswoman for the Flockton Cluster Residents Group Jo Byrne said the loss of value option meant homeowners were not left with uninsured land.
"But we're still stuck between a rock and a hard place because there's no way of remediating our land on a property-by-property basis but we don't even know if this [form of settlement] is legal and we don't know what is happening with area-wide mitigation," she said.
$270m Ruataniwha dam scheme at risk of being 'put on ice'
21 May 2014 – Dominion Post
The proposed Ruataniwha dam is resting on a knife-edge, with big investors pulling out and a draft resource consent that makes the $270 million project unworkable, according to the company behind it.
Many strands need to come together if the scheme is to go ahead, a crowd of 60 people were told at a public meeting in Havelock North yesterday.
First, there must be what the Hawke's Bay Regional Council deems a "viable" resource consent.
The draft consent issued by a board of inquiry last month includes a limit for nitrogen leaching that would make the scheme unlikely to proceed, as it would not allow for intensive farming operations.
In a frank and "personal" talk yesterday, Andrew Newman, chief executive of the council's investment company, said he felt "the pendulum has swung slightly too far" in favour of the environment in the board's decision.
He said the boom in dairying over the past 15 years meant "the regulatory system has lagged behind the environmental impacts of that intensification".
"The regulatory system is trying to catch up, but I just think maybe in this case the pendulum might have swung slightly too far the other way."
The council has submitted to the board that the proposed limit of 0.8 micrograms of nitrogen per litre of water in the Tukituki catchment be altered to a figure that "more closely reflects existing water quality and provides for reasonable land use intensification to occur".
The submission is one of 28 received on the draft. The board must make its final decision by June 28.
If a viable consent was not issued, the scheme would be "put on ice", Newman said, as it would probably mean insufficient demand for water.
And if there was insufficient demand, it was unlikely investors would be found.
Ngai Tahu Holdings Corporation and Trustpower had pulled out of their possible $100m investment in the scheme, but two other large investors were interested, he said.
One of those institutional investors was capable of putting in the entire amount on their own, or possibly more, "subject to a couple of key issues being sorted out".
He would not divulge who the potential investors were but said they involved "New Zealand-based money".
"We've put it [the investment process] in a bit of a holding pattern while we understand what the final impact of the board of inquiry decision is," he said.
Yesterday's meeting was part of the council's consultation on whether it should invest up to $80m in the scheme.
It will make its decision by June 25
Help for Christchurch flood-prone areas
21 May 2014 – The Press
Mayor Lianne Dalziel has announced the publication of taskforce flood reports and flood defence tools proposed to help with flood mitigation.
The Avondale area
Significant slumping of the banks of the lower Avon River caused by liquefaction and lateral spread has increased the area's vulnerability to flooding. Temporary stopbanks have been constructed along the river's edge but bank slumping and fill consolidation are still happening, which means the stopbanks are lower than the river flood level. They cannot be removed until an alternative alignment for permanent stopbanks has been determined. Temporary fixes include checking, repairing and replacing the flap gates along Avonside and Hulverstone drives and installing pumps during major events to keep ponded run-off from reaching low-lying property. Longer term, holding basins could be formed in the residential red zone, away from the residential green zone properties. Run-off could be directed to these basins.
The Lower Heathcote catchment (riverside properties)
River flooding has been seen along the lower reaches of the Heathcote River and the streets next to it, with water depths of up to one metre. Ground levels in the area have changed since the quakes and the capacity of the river has reduced due to bed heave and sediment deposition. Stormwater pipes next to the river have also been damaged. For the 13 most vulnerable homes, solutions such as house raising or house wrapping will be the only option that will protect them from major flooding. It says temporary bunding (using large and small sandbags) and relocatable pumps could reduce the flood risk for up to 168 properties in the area while longer-term solutions are investigated. The taskforce is also recommending that the existing tidebank heights are increased beyond current design level to incorporate flood level protection, sea-level rise and climate-change considerations.
The Dudley Creek catchment
This area has a long history of flooding but has experienced five big floods since the earthquakes. Significant settlement has occurred in the catchment, and lateral spreading and bed heave have affected Dudley Creek and its tributaries, reducing their capacity. Long-term options for easing the flooding risk are expected within three years. In the meantime temporary protection measures could include lower catchment capacity enhancement works, street bunding, local drain improvements, house raising, house tanking, and temporary buy-outs.
Slips, rather than flooding, have been the problem in Lyttelton. To reduce the risk of further slips, the taskforce says street sumps should be regularly cleaned and where possible protected from blockage from gravel and floating debris. It is also recommending the stormwater drainage network on hillsides susceptible to slipping should be increased in capacity and that work should be done to locate and repair water supply leaks.
Little River has a long history of flooding, with no evidence of a difference in flooding before or after the earthquakes. The main cause of recent flooding is inadequate channel capacity of the Okana River corridor and the effect of the Wairewa Pa Rd bridge. The task force is looking at clearing the river and stream channels throughout the area and creating secondary flow channels to contain spill from the main channel. It also wants to increase the capacity of the Wairewa Pa Rd bridge and investigate options for re-routing drainage from the Christchurch Akaroa Highway.
Nitrate limit 'tougher than for drinking water'
23 May 2014 - Stuff
The draft decision of the Ruataniwha Board of Inquiry has set a "nonsensical" nitrate limit in the Tukituki River that is 14 times more stringent than the international drinking water standard, according to HortNZ.
HortNZ president Julian Raine said he used the comparison to show how difficult it would be for growers and orchardists to work to the nutrient limits set down by the board.
"I queried the figure of 0.8 milligrams of dissolved nitrate per litre that has been quoted as the limit. I then asked a technical expert who calculated what it would mean in terms of the international standard for drinking water," Raine said.
Asked why the board would set such a limit, Raine said "it doesn't make sense to me".
His drinking standard calculation is supported by a water quality specialist who did not want to be named. He added that the board of inquiry investigated other standards besides drinking water.
Raine said the suggested nitrate nutrient limits would have an impact on vegetable growers whose products were processed by companies such as Heinz Wattie's.
"The vegetable industry is investing in extensive research on the measurement and management of nutrients within complex rotational farming systems but we do not have all the answers today," Raine said.
"Our initial assessment is that limits set in the draft are likely to have a big impact on what crops can be grown and potentially the investments that large food companies may make in the region."
Crops that would be affected include potatoes, onions and green vegetables.
Besides the issue of nutrient levels, HortNZ is also concerned about the river flows regime, which it says will not support low impact horticulture unless the dam proceeds. Growers and orchardists would have to find other water sources, most likely deep bores, he said.
Meanwhile, Federated Farmers Hawke's Bay provincial president Will Foley said it was not certain whether the 0.8mg figure was an "absolute or aspirational target".
"If it's aspirational with a timeline of 25 years to meet it, then I believe that in time technology will solve this - just in the way sewage treatment has been improved," Foley said.
He called on the board to re-evaluate the evidence of experts like Niwa and the Cawthron Institute, which had been ignored "perhaps not intentionally".
Foley said the board's draft decision "means existing sheep and beef farmers and horticulturists will need a consent as our current farming methods will be deemed to be against the law under this draft decision. That is whether the dam proceeds or not.
"Sheep and beef farmers like me will likely need a consent just to do what we do now."
Rockfall shuts Arthur's Pass
23 May 2014 - The Press
Arthur's Pass has been closed because of a massive slip and is expected to remain closed for two or three days. The NZ Transport Agency's senior network manager Mark Pinner said a significant amount of rock and material was brought down on the highway by heavy rain over the past 24 hours. The 100-metre-long slip happened about 1km west of Otira this morning, closing State Highway 73. A second slip, about 20 metres long, happened further west at Aitkens, and flooding had been reported at Kelly's Creek.
Motorists were advised to take SH7 through Lewis Pass instead. Rail services have not been affected. "As the rock and material are still falling onto the highway, our contractors are unable to get to the slip to begin clearing it," Pinner said. Given the volume of material that had slipped, he estimated it would take two to three days to clear.
SH6 through Haast Pass, from Haast to Makarora, also remained closed today after the heavy rain caused more rock and material to fall at Diana Falls. Pinner said the slip "proves the need" for the work NZTA was doing to clear the Haast slips and put barriers in place. It also reinforced the need for the overnight closures of Haast Pass that have been in place since late last year.
He said the new slips could hold up the clearance work, but in the long run it would be helpful to be more aware of the vulnerable land so NZTA knew what needed to be cleared and stabilised.
Residents fight to protect creek
26 May 2014 – Marlborough Express
Springlands residents are ready to kick up a fuss to ensure the Marlborough District Council hears their concerns about stormwater being drained into Murphy's Creek.
About 40 people, mainly residents who live near the creek, gathered at Springlands Tavern in Blenheim on Saturday to discuss how they could get the council to listen to their concerns about the creek being damaged by stormwater from the Westwood Retail Development and planned housing subdivisions.
They wanted the council to stop piping excess water into Murphy's Creek because it had caused flooding, poor water quality and killed off aquatic life.
Friends of Murphy's Creek chairman Fergus Murray said he had met with Blenheim councillor Terry Sloan to discuss the issue.
"I had a frank discussion with him and asked why no-one was taking any notice and he said we haven't jumped up and done enough.
"[So] we are going to tell them what we should be doing because they are not doing anything fast enough."
Murray said they had sent emails to each new councillor in the region asking for their support but had not received one reply.
"It is important to keep the pressure on council else they will ride over us and do what they want." The issue was not only of concern to the residents living near the creek, it affected everyone living in the region, he said.
"We've got a beautiful, pristine creek - well, we do at this stage - and we are the guardians of the creek."
Resident Ross Inder expressed his concerns about the pollution of the creek.
"Murphy's Creek delivers 55 per cent of the water the Taylor [River] relies on coming into town. It delivers more than all the other spring-feed streams put together, so if they are going to pollute this one, it's a big step towards total pollution of the Taylor [River].
"It's a very stable stream bed and it's got a very stable flow and you're going to upset an aquatic infrastructure if you are going to treble the flow at any stage."
Inder said he wanted to focus on getting the message through to the council, not just pressuring them.
"I think it's time we made things a little bit more voluble, because if one person can change the design of a roundabout, surely 40 people can change the thinking of council on this.
"We want to get the message across that it is not just something affecting us personally and our property, it's part of the larger picture of responsible management of the waterways of the town," he said. "For the manager of the assets and services committee to say that storm water run off doesn't incur flooding is absolute bollocks."
Another resident Lindsay Dahlberg said he was one of the 23 people to make a submission to council about the issue of water flooding onto private property. He said he felt the council was not paying any attention to them.
"We sent a letter to every new councillor. We have not received a response from one of them about our concerns . . . they have ignored us ... It shows we have to continue to be more vocal."
Resident Tom Miller said the council was "pretty hard to try and get through to". He said this was not a short-term plan for the creek, he wanted it to be solved long-term. "We've got to . . . look to the next 40 to 50 years."
Murray said the next step for Friends of Murphy's Creek was to focus on gathering a strong support base.
Citizens fouling waterways
29 May 2014 – The Press
Household and vehicle contaminants pouring into stormwater systems and polluting Christchurch waterways could take generations to clean up, new research shows. Data collected by the city council for the Avon Stormwater Management Plan shows the waterway contains harmful contaminants affecting the river and human health.
Experts say it is a wake-up call to city residents that the finger should not just be pointed at farmers for polluting waterways - anyone who drives a car or lives in a house has responsibilities.
The "worst sites" in the city with indicators showing human waste exceeding safe levels are Dudley Creek, Riccarton Stream and the Avon at Manchester St.
Sites exceeding safe levels for water quality, with nitrates, phosphorous, dissolved oxygen, zinc, copper and ammonia were Dudley Creek, Riccarton Stream, the Avon at Mona Vale, Waimairi Stream, Horseshoe Lake and Addington Brook. Maps of the catchment showed the Addington area scored high in petroleum hydrocarbons, copper and zinc.
City council unit manager, natural environment and heritage, Helen Beaumont, said E. coli from human waste was entering waterways as a result of the earthquakes rupturing pipes.
Freshwater ecologist Professor Ian Hawes said the source of many contaminants was from everyday sources, which few people realised.
"Everyone who drives a car has zinc from brakes which then go on to the road. That is washed off the road into the stormwater drains, which goes into the estuary.
"It is the same for everyone who lives in a house. If you have a galvanised roof or copper pipes, contaminants slowly wash off through rain and go into the stormwater," said Hawes.
The Christchurch-West Melton Zone Committee, which requested the information, said the results would shock householders.
Chairman Ian Fox said: "Focus has been on what dairy farmers contribute to water quality but people in urban areas are also harming waterways . . . which could take generations to repair.
"Is it possible to get it clean? Yes it is. Is it going to be easy? No, and that is because we have 350,000 people living here.
"We have had 160 years of messing up our waterways. Now we all have a part to play in cleaning them up."
Beaumont said the focus was now on reducing contaminants, then treatment of stormwater.
The sites that were cleaner include the airport catchment, Wairarapa Stream and Waimairi Stream.
"Urban waterways are a challenge - there is an intense duck population, cats and dogs and all the road runoff.
"But we can do good housework by not putting paint down the drain and thinking, where is this water going to end up," she said.