Water and Waste

At our September meeting, we welcomed Mike Bourke from Christchurch City Council to our Monthly Connections Meeting. Mike answered questions about the water issues/solutions in the Halswell ward and the three waters reform. Mike is the Senior Technician, Water & Waste Planning at CCC.\nHe described what the 3 waters reform meant for Christchurch \n and for Halswell as well as issues around chlorination, water shortages, metering and charging for water.\nMike outlined the progress CCC is making on upgrading the infrastructure to try and keep chlorine out of the water and how waste and storm water are managed. As part of the discussion we also discovered that water can be dated! and that this is a crucial piece of information in the fight to keep Christchurch water free of Chlorine.

Questions.

What does the 3 waters reform mean for Halswell?

The 3 waters reform is a government initiative to ensure safe water to all New Zealanders and came into being after the Havelock North e coli incident. It amalgamates all water providers into 4 distinct entities which takes control out of the hands of elected members and effectively puts it in the hands of a company.

One issue not yet clear is who then owns the assets. Current and future citizens of a city will be paying for the assets but how will that be recognised?

What happens if the government does take this over?

This is one of the key things to work out going forward. Mike outlined that the current system was unfair as it stands as water rates are based on CV of the house not the amount of water used. The new entities and the assets will be regulated but the costs in doing this are as yet unknown. It is however unlikely to save any money.

The council have started charging for excessive water use ovr 700l a day. Its a start to make people value water but currently a single person can be paying the same for their water as a large family if the house value is the same.

How do the council charge for wastewater?

This is based on the proportion of the water used by the house.

Is Christchurch short of water?

Not currently. Christchurch draws its water from huge underground resources which have an estimated capacity of 75 million m3 . Currently we draw around 55 million m3 which is well within capacity but with continued growth we could get there.

Mike agrees with the idea that we should be paying for water in some shape or form simply so that people value it more as a resource - like they do internet, phone etc.  There are different options in this. For example households could pay for every cubic metre used or households could opt in to pay for every m3 if they think they use less than the average designated by the council in the rates. Perth has this as an option for residents.

The problem will always be the societal extremes. Some people who can’t afford it could end up with big bills.

One suggestion would be including water consumption on the rates bill so people could see how much water they actually used.

Do all the new subdivisions have water metres?

Yes. All properties have a metre. Even the older ones.

Will Christchurch water continue to be chlorinated?

Mike said he would like to think not. The problem is the national system compares apples and oranges.  Christchurch is compared to other areas who draw their water from underground, however our water comes from a very different source than Havelock North where the e. coli outbreak was down to extreme conditions and poor infrastructure.  By comparison, Christchurch water comes from deep aquifers and CCC have invested in upgrading the infrastructure to prevent this occurring. For example, bringing the well heads above ground to prevent backflow.

Some wells cant get very deep so are UV disinfected. CCC has never confirmed e. coli from the wells
Having a non return valve on every property prevents backflow into the system.
The concrete roofs on reservoirs need sealing and fixing as the concrete is porous and allows runoff into the water stored inside.
Once these upgrades are finished CCC will put forward their case to the government for no chlorine in Christchurch water. 

What about nitrates? How is CCC working with the regional council on that?

Nitrate levels are a point of discussion. Christchurch levels are currently well within guideline levels but there is research suggesting those levels are still too high. The groundwater that feeds the aquifers comes from water flowing from Halkett/West Melton and North Canterbury flowing under the Waimakiriri river

ECAN are currently looking into rising NItrate levels that could be coming from North of the Waimakiriri as high levels have been detected north of the Waimak and that water flows under the river into the Christchurch groundwater

The underground water is filtered by both abiotic and biotic systems. Natural filtration removes most suspended matter from groundwater as the water passes through porous layers of soil and rock into the aquifers. Biotic factors are affected by high levels of nitrates which is why it is so important to monitor and reduce these levels.

Snow melt does end up in the Waimakiriri but not much recharges the aquifer as once it passes Halkett the water surfaces and runs off to the sea.

Water monitoring / dating.

Mike explained that water can be dated! In order to draw from the underground water, monitoring has to show that the water in the wells is at least 2 years old. Thi sis done through carbon and tritium dating and modelling can tell where the water entered the system and when. Some of the water in the wells is 175 years old.

Water Reform Costs? The government say the reforms will save us billions. Where do the savings come from?

How will the government do the same thing as the councils and do it cheaper?

The reforms will improve water for smaller, rural centres, not for the bigger centres like cities. The reforms aim to reduce the huge gap in NZ betweenthe top and bottom of water quality and access.

The savings would presumably come from the reduced levels of management. Whether this is a good or bad thing is up for discussion.

There is so much work to do in some regions and communities that it cant possibly save money.

Ross raised concerns that Christchurch water assets are worth $6.9 Billion with $1.1 Billion in debt meaning a net worth of $5.8 billion yet the government are offering Christchurch $122 million. There is a clear inequity in the argument when other communities who have not invested in their infrastructure are being offered similar amounts of money for assets worth far far less.

Ross also questioned whether the costs paid by developers would remain in the local area as if water is no longer controlled by the local council these fees would end up elsewhere in the country. Whilst he was certain most people would not have an issue subsidising the infrastructure upgrades in rural areas for example, he though people would have an issue with selling $6.9 billion of assets for $122 million!

Another issue raised was that of stormwater. Especially in Christchurch where swales and retention basins are an integral part of the landscape, parks and green spaces. How will they be managed if the council no longer control them.

Mike agreed that there were a number of issues the government had yet to address:

Stormwater
Ownership of assets

What's going on with Stormwater in the area?

New developments are responsible for managing the stormwater that development will generate. The idea is that they develop systems to mitigate the runoff so that it would be no more that that generated by the site in its undeveloped state.

The big storm in May 2021 suggests that the mitigation works. Flooding was far less than in previous events before the retention basins and wetlands had been developed.

When developing a site the developer needs to tak into account the wider basin and the impact any building may have on that, particularly since the earthquakes raised the groundwater levels in the area..
This is why long term land use plans are so important and cant just be changed as any change of use can impact another area.

Mike suggested that every household should have a stormwater system to collect the rain off the roof and reuse it.

Any truth to the rumour that the Sutherlands retention basins are over allocated?

Mike wasn't sure about this but probably not.

 

Can you use Pressure sewage tanks to collect and pump out storm water?

No. Definitely not. This is a myth. People see the tanks and think they are for stormwater but they are only for wastewater

In TC1 areas sewers have been replaced by pressure sewage tanks which are more robust and can be pumped out if needed