Dialogue: No more Russian roulette with city's water supply

By BRUCE HUCKER*

In 1994, when the Auckland region was in the grip of a severe drought and water shortage, an emergency pipeline was proposed to take water from the Waikato River to the Ardmore treatment station.

It was, at best, a stop-gap measure and fortunately it rained before the pipeline was built.

It would not have added to Auckland's water supply, but would merely have replaced raw water from the Hunua dams with water from the Waikato River.

There is nothing stop-gap or emergency about the Waikato River project that is scheduled to begin construction at the end of next month. Auckland needs the new water supply to cater for the growth in population since 1994 and the increase that is expected to lift it beyond two million people within the next 25 years.

At present, Auckland relies on regular rainfall to replenish the dams. We are fortunate that since 1994 it has rained sufficiently for Watercare to maintain a normal supply.

However, in May we had evidence of our precarious position when the lakes were down to around 70 per cent full, very similar to the levels pre-1994.

Without normal winter rainfall since May, we would have needed major restrictions next summer.

Last month was wet and the dams are now nearly 90 per cent full. But we cannot go on playing Russian roulette with our water supply. Water restrictions place hardship on all sectors of the community, from both health and economic standpoints.

What is even more concerning is that the Auckland water demand is increasing at a rate which will exceed Watercare's average yield of 331,000 cubic metres a day by the end of 2002. And that is without having any provision for the loss of storage availability through natural phenomena such as algal blooms or the decommissioning of Cosseys Dam for planned maintenance.

Soon after the 1994 incident, the Auckland territorial local authorities requested Watercare to meet the international 1-in-200 year drought standard. This translates into a normal supply 99.5 per cent of the time. Today, Watercare doesn't even meet the old 1-in-50 year standard.

Watercare has a legislated responsibility to ensure we have a safe, secure water supply and it has taken appropriate steps to achieve that goal. The Waikato River is the only scheme that will meet the required drought standard and has the significant advantage of not being reliant on rainfall. Every day the Waikato River pours 17 million cu m of fresh water into the Tasman Sea.

Opponents of the Waikato River project wish to reopen the debate.

North Shore city councillor Joel Cayford argues that incremental, less capital-intensive projects, such as the Lower Mangatawhiri Dam or the Wairoa River, are a better way to go.

This may sound attractive in theory, but is dangerous in practice. Apart from the difficulty and the time associated obtaining resource consents, his proposal takes no account of Auckland's situation. It would simply reinforce the likelihood of serious water shortages, a situation the Waikato project is designed to avoid.

Opponents have also attacked the quality of the water to be delivered to the people by the pipeline. They seem to be encouraging the belief that the catchment lakes are pristine and do not require treatment, whereas the river is sub-standard. This is untrue.

Watercare must treat all of its supply to meet or better New Zealand drinking-water standards. These are based on the World Health Organisation recommendations and Watercare has upheld them to the degree of being rated A grade by the Ministry of Health.

The Waikato River's treated water will also meet or better those standards. It is beyond comprehension that the councillors and staff of the territorial local authorities that own Watercare, or Watercare's directors, management and staff, plus international and local advisers, would conspire to put sub-standard drinking water into the Auckland distribution system.

Watercare and its owners are extremely jealous of the company's quality rating and throughout all of the examination of alternative water sources, the delivery of top-quality treated water was the paramount criteria.

That is why Watercare has erred on the side of caution by accepting a tender to build a treatment plant incorporating cutting edge technology.

The Zenon membrane system, which forms the heart of the ultrafiltration technology, guarantees against contamination from pathogens such as giardia and cryptosporidium. Combined with the other treatment components, such as granular activated carbon, coagulation and chlorine, the process also filters harmful minerals and chemicals.

An advantage of this system is that the membrane technology allows for the amounts of chemicals in the treatment process to be reduced markedly.

The treated water entering the Redoubt Rd reservoir in Manurewa from the Waikato pipeline will be the same as or better than that coming from the Ardmore treatment station.

For the five years before awarding the construction contract last October, Watercare worked through the procedures to make the scheme a reality. Rigorous evaluation was followed by an extensive communications programme involving all sectors of the community.

Then came the consent process, from the examination by commissioners appointed by the Waikato Regional Council to the dismissal of appeals to the Environment Court.

Aucklanders are meagre water users by international standards. The average daily consumption is 195 litres, compared with Wellington (250), Christchurch (284), Sydney (351) and Adelaide (364). A great deal has already been achieved in reducing water demand in Auckland and, therefore, the opportunity for additional savings is relatively small.

In 20 to 25 years, Auckland may be looking for another water source. This is the inevitability of a growing region. Where that source will be has yet to be determined. The only certainty is that we all need high-quality water to survive, and Watercare, with the support of its owners, has accepted the challenge to deliver.

* Dr Bruce Hucker is the deputy mayor of Auckland City and chairman of the Watercare Shareholders Representative Group.