Prepared by: Joel Cayford
For: Watercare Shareholder
Representatives to Consider
Dated: 1st November 2002
1. Introduction
This paper has been prepared in response to the need for the Watercare SRG to consider its policy in regard to Greater Auckland’s water supply. Four of the six Councils which are represented on the Watercare SRG have resolved to support the use by Watercare of the “best raw water sources first”. These resolutions arose as a consequence of the completion of the Waikato Pipeline water source, and Watercare’s intention that this source should be used at all times – even when other existing sources could meet demand. The two largest users of water – namely Auckland City Council and Manukau City Council – support continuous, and non discriminatory use of the Waikato River source for drinking water supplies.
2. Why
“Best Raw Water First”?
The reasons for advocating “best raw water first” include:
2.1
Health risk management
This practice has been misinterpreted by many as meaning how to minimise the health risks from individual sources of supply. For example – how to minimise the health risks while using the Onehunga Bore supply, as part of the region’s supply. However health risk management is about minimising health risks for the whole water supply – and only choosing those sources which present the least health risk.
The arguments are best put by Michael Taylor – Ministry of Health’s senior adviser on health of water supplies. In his 2002 paper: Complementing drinking-water standards with risk management – he writes:
“The Drinking-water Standards for New Zealand:1995 and 2000 set out clearly the monitoring required to demonstrate
compliance with the Standards. They also provided a statistical basis for
the frequency at which monitoring samples should be taken.
Monitoring is an important tool in water supply
management. Adequate monitoring of
drinking-water quality provides the water supplier with the information
necessary for making decisions about the management of the supply. Water quality data may show the need for
improved catchment management, treatment process performance, or the
effectiveness of measures to avoid contamination of the water in the
distribution system.
Despite the importance of monitoring in water
supply management, alone it is of limited value. The detection of contaminants in a water during monitoring indicates
that something has already gone wrong, and that consumers may already have been
exposed to a microbiological or chemical hazard. A more effective way of protecting public health is to stop
contamination in the first place.
The use of risk management
principles provides a greater certainty that the water being provided to the
public is safe than is given by merely monitoring compliance with
standards. This approach to water
supply management leads water suppliers to look at what can possibly go wrong
in a water supply, pinpoint what the causes of this event may be and having
identified the possible causes, take actions to reduce the likelihood of the
event occurring.
Action plans to address the public
health risks associated with water supplies are termed Public Health Risk Management Plans. These should show how risks to public health that may arise from
the drinking water provided by the supply will be reduced….” (underlining emphasis added)
In other words, compliance with NZ drinking
water standards – which include MAV standards for a range of chemicals, and a
monitoring regime – DO NOT represent a
complete health risk management approach. By themselves, as they stand,
NZ drinking water standards do not work to minimise health risks.
It is perhaps understandable that NZ is not
adopting best practice when it comes to drinking water supply health risk
management. We are a new country, and most communities have been able to draw
water supplies from relatively pristine raw water supplies. However Greater
Auckland has begun to stretch the capacity of its existing sources, and for a
variety of reasons which won’t be explored in this paper, has chosen to draw
water from a relatively contaminated river which drains a developed catchment.
Other countries have not been so fortunate.
They have been forced to draw drinking water from many sources for some time,
and have been forced to develop health risk management plans some time ago. We
can learn from their experience. The following is an extract from Melbourne
Water’s Annual Plan – 2001:
“ Melbourne is
widely regarded as having high quality drinking water. There are a number of
reasons for this, the main one being the purity of the source. In Melbourne,
more than 140,000 hectares of natural forest has been allocated for harvesting
water. Approximately 90 per cent of our water supply comes from these
uninhabited catchment areas. As a result, Melbourne has a predominantly
unfiltered water supply. Melbourne is one of only about five cities in the world
that have such catchments.
It is then stored for up to five
years to help purify it through a natural settling process. The result is water so
pure, it requires only minimal treatment to meet standards set by the National
Health and Medical Research Council.
Closed catchments minimise the risk of human-borne
disease entering the water supply system. They provide the best protection
against contamination of the water supply by Cryptosporidium, Giardia and other parasites.
In Melbourne the microbiological safety of the water
supply is achieved through a series of barriers to the entry and transmission
of pathogens throughout the system. These are:
§
Uninhabited catchments for the harvesting of water
§
Long retention times in major catchment reservoirs
§
Additional retention time in seasonal storage systems
§
Conventional treatment or microfiltration of water that is not harvested
from protected catchments
§
(approximately 10 per cent of water requires full treatment)
§
Disinfection of the water before it enters the distribution system
(chlorination is predominantly used)
§
Closed distribution systems to avoid any possible recontamination
As a result the greater
metropolitan area enjoys a consistently high standard of drinking water….” (underline emphasis added)
Of note is the repeated reference to “protected
catchments”. Also of note is the reference to “long retention times in
catchment reservoirs”. These are all referenced as “barriers” to the entry of
contaminants to the raw water supply. However Melbourne Water is not making up
these arguments themselves. There are powerful regulatory bodies in Australia
which require this sort of attention to health risk minimisation. This is in
sharp contrast to New Zealand – where even the NZDWS are not mandatory. In
Greater Auckland the only regulatory body which has legislatively enshrined
control over Watercare is the SRG.
Part of Australia’s regulatory environment for
water health quality is described in the Australian Drinking Water
Guidelines. These are described as follows:
“ …According to the Australian Drinking Water Guidelines, ensuring the microbiological safety of a water supply entails a wide-ranging program of protection, treatment and monitoring, with barriers to the entry and transmission of pathogens throughout the system.
The barriers should include most of the following:
·
The water sources selected should
be protected from contamination by human or animal faeces and an active
catchment management program maintained.
·
Water should be pre-treated, for
example by detention and settling in reservoirs for long enough to allow
bacteria to die off (at least several weeks but preferably longer).
· Water storages should be protected from public access, malicious or accidental contamination and vandalism.
· Some form of treatment (such as coagulation, settling and filtration) should be carried out.
· The water should be disinfected before it enters the distribution system.
· An adequate concentration of disinfectant should be maintained throughout the distribution system. This is referred to as the disinfectant residual.
· The distribution system should be secure against possible re-contamination.
In addition, the Guidelines discuss monitoring for microbiological
quality as a check that the barriers to contamination are working….” (underline
emphasis added)
Again, it is clear that the use of protected
catchments is a priority for health risk minimisation. Also note the explicit
reference to raw water detention and settling prior to use as a raw water
source for drinking. River sources –such as the Waikato - do not offer the
settling and detention characteristics of reservoirs and lake storage systems –
such as the Hunua and Waitakere Lakes.
Health risk management and risk minimisation is
clearly at least as much about choosing uncontaminated raw water sources, as it
is about treating raw water. The above extracts are primarily drawn from
Australia, however the international literature is abundant in references to
cities such as New York where best raw water sources are chosen over and above
highly treated contaminated raw water sources.
2.2
Catchment Management
With the best will in the world, neither Watercare nor Greater Auckland for that matter, can manage the discharges which occur in the Waikato Region and which inevitably end up in the Waikato River.
Despite commitments made between Watercare and Manukau City Council at the time of the Environment Court scrutiny of Watercare’s application to take Waikato River water, very little of any substance has been achieved by the Greater Auckland Region in terms of controlling what happens in the Waikato Region.
The Greater Auckland region has no catchment management control over the Waikato catchment. In fact the Resource Management Act explicitly separates the jurisdictional control over natural waters between respective regional councils at the Bombay Hills. This is the line between Auckland and Waikato regions. Consideration of the effects of the Waikato Pipeline project were explicitly separated by agreement between the TAs and Regional Authorities involved. Waikato Region considered the effects on the Waikato River of taking water into the pipeline. Auckland Region could not consider the effects of the water once it was inside the pipeline because the RMA has no juridiction over water inside a pipe. There was no RMA linkage between Waikato Region catchment management and Greater Auckland drinking water supply.
Information readily available on MfE’s and Environment Waikato’s websites clearly indicate Waikato region has major problems with non-point agricultural runoff. EW’s site catalogues some of the 2000+ point source discharges which are permitted. Most months the NZ Herald notifies further applications to discharge into the Waikato River, as inevitable industrial development and expansion continues in that fast-growing region. While some older discharges are being slowly cleaned up, the fact remains that Waikato River water is heavily contaminated.
The recent toxic spill which forced the closure of the Waikato Pipeline source is the most recent and visible example of the extent to which contaminant levels in the Waikato River can vary. That coloured spill is perhaps the tip of the iceberg of other less visible acts of disposal.
Of relevance also is the recent press coverage of the bottled water plant which is reporting elevated levels of suspended solids in drinking water. In the press reports Watercare conceded that the level of suspended solids in treated Waikato water is about double that from existing supplies. Elevated suspended solid levels are characteristic of raw water supplies which have not been detained in lakes and reservoirs prior to use. It is relevant to note that certain chemical pollutants and pathogens attach themselves to suspended solid particles for transport in water.
2.3 Endocrine
disruptors
The human gut produces a huge quantity of bacteria which are excreted as part of faeces on a daily basis. The most common and easily measured organism is E.Coli, which is referred to by wastewater engineers and scientists as faecal coliform. It is the presence of these faecal coliforms that the drinking water standards and recreation standards are concerned about. Many of the bacteria occuring in human waste are harmless – however there are some disease organisms – or ‘pathogens’ – that can bring harm.
Wastewater – such as is discharged into the Waikato from the various wastewater treatment plants, especially Hamilton’s WWTP – contains metals, chemicals and hormones from households (via food and household products) and business processes. There are two issues: if large quantities are discharged into small amounts of water, there may be direct pollution problems. The other issue is ‘bioaccumulation’ of various of these chemicals in the food chain. This can bring unacceptable concentrations in humans and aquatic life, which can lead to health problems.
The endocrine system in the human body is a complex network of glands and hormones that regulate many of the body’s functions, including growth, development and maturation, as well as the way various organs operate. The endocrine glands – including the pituitary, thyroid, adrenal, thymus, pancreas,ovaries and testes – release carefully measured amounts of hormones into the bloodstream, which act as natural chemical messengers. They travel to different parts of the body to control and adjust many life functions.
An endocrine disruptor is a synthetic chemical which, when absorbed into the body, either mimics or blocks hormones and disrupts the body’s normal functions. This disruption can happen through altering normal hormone levels, halting or stimulating the production of hormones, or changing the way hormones travel though the body. There are concerns that, for example, the decline in fertility levels in some countries is a result of this.
The issue is relevant to wastewater amd drinking water issues because many of these substances will enter the foodchain – either on land or in waterways – from wastewater discharges. Some of the chemicals – eg pesticides and others – will enter the Waikato River via runoff from farms and roadways. Water treatment systems will screen some of these chemicals, but generally treatment processes are not designed to deal with this problem because often DWS do not list such chemicals.
There are currently no central government guidelines within NZDWS on what levels these chemicals can exist in drinking water. This may change. In Europe especially there is considerable focus on synthetic chemicals entering drinking water supplies. Many common pharmaceuticals such as birth control drugs are measureable in tap water in Belgium, Germany and Britain.
2.4 Non-compliance with
existing NZDWS
The present Waikato drinking water source does not comply with NZDWS 2000. To comply the source needs to be operated and monitored continuously for a period of twelve months. Watercare has previously indicated the source did fully comply with NZDWS 2000, and this untruth has also been replicated by TLAs and communicated to their customers. In recent weeks Watercare has corrected this information, and now notes that it “maintains” the NZ Drinking Water Standards. Though what this means I am unsure.
It was always an option to operate the source for a year – without adding it to Auckland’s water supply and subjecting the community to risks associated with an unproven treatment plant and source.
New regulation waiting to be passed into legislation includes Ministry of Health proposals that Health Risk Management Plans be mandatory. In addition, the Local Government Bill includes requirements for TLAs to produce Water and Wastewater Assessment plans which envisage comprehensive economic analysis. It is unclear whether these changes apply to LATEs such as Watercare.
The Waikato source does not comply with existing NZDWS. In my opinion, any health risk management plan would put the Waikato source near the bottom of the list of Auckland’s existing sources. Best practice would be to only use it when necessary.
2.5 Cost minimisation
Because of costs of treatment and pumping, treated water from the Waikato River source is significantly more expensive than supplying treated water from the Hunua Lake sources which presently make up around 70% of Greater Auckland’s storage.
Watercare is required by its SCI to minimise operating costs. Insisting on running the Waikato source while dams are full conflicts with the SCI.
Watercare has consistently argued that intermittent use of the Waikato source is not feasible, whereas mothballing is technically feasible. At present Watercare has indicated that the minimum operating capacity of the Waikato source is around 15,000 – 20,000 cubic metres/day. I am advised this limit appears to be caused by the time it takes water to get from the plant to Auckland. Three days is regarded as the maximum allowable time before residual chlorine levels decline to an unacceptable level. However if the small amount of water reaching Auckland was not used for potable purposes – unless explicitly required, then less could be pumped, still keeping the plant operating but at a very low “tick over” rate.
2.6 Agreements with
tangata whenua
When the Waikato Pipeline was proposed in 1994, Tainui offered a clear agreement for water to be taken “in emergencies”. Tainui also wanted the catchment cleaned up. During the hearings conducted as part of the Auckland Regional Water Review, submissions from tangata whenua across the region – and outside – were consistent in their view that using Waikato water in Auckland was problematic. The collective view appeared to be that Waikato water should only be used in emergency.
These submissions have not been given effect to by Watercare SRG.
2.7 Drought standard
maintainance
The region has adopted a 1:200 year drought standard. The Watercare SRG officers group have indicated this needs to be revised and have proposed the consdiration of a 1:75 or 1:100 standard.
It is clear that the sheer existence of the Waikato Pipeline source significantly drought proofs the region – even without continuous use. A balance needs to be struck between using the source all the time for drinking water supplies – even at a low level – and at explicit times when an agreed level of risk is reached.
3.
Best Practice
International drinking water supply best practice is clearly about minimising human health. Evidence is clear that protected catchments and long detention times in reservoirs and lakes play a significant part in health risk minimisation.
In Auckland, we have the natural resources to draw drinking water supplies from protected catchments and lakes with long detention times. We should do this. Not only are these sources safer, they are also cheaper to run – requiring less electricity (and therefore more ‘sustainable”). They require fewer chemicals to treat, and produce less toxic filtrate for disposal.
Tangata whenua have expressed their desires. We can give effect to those without compromising the water needs of the region.
We have built a less safe supply which can be used as a backup in times of drought. It should be used for that purpose. ‘Best raw water first’ is best practice. The SRG has the power and the responsibility to require Watercare to adopt this practice. ENDS