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Swimming-water quality
Introduction
Surf's up. What about e.coli counts?
Over 340 swimming sites recorded unsafe bacteria levels during the 2010/11 summer. Before you head to the beach, find out if your favourite spot is monitored. Our database contains water-sample compliance rates for the last 2 summers.
Plus find out which sites have a water quality grade.
Monitoring results
Waihi Beach has been lucky. The Bay of Plenty holiday spot escaped the oil slick that coated much of the coastline after the Rena disaster. But holiday makers would still be wise to watch where they bathe. Three Mile Creek flows into the sea at Waihi and has a permanent health warning to avoid swimming.
Treated effluent from the Waihi Beach Wastewater Treatment Plant flows into Three Mile Creek. But the local council says testing shows far more contaminants enter the waterway from farmland upstream of the plant. Last summer, e.coli counts in the creek jumped to 4700 per 100mls of water – over 8 times the level considered "safe" to swim.
It's a scenario being played out around the country. Our water quality is considered good by international standards; yet pollution from sewage, stormwater and agricultural run-off is threatening many of our rivers and beaches. Unlike the oil slick from the Rena, the immediate effects can be much harder to see.
Results worse
Monitoring results indicate swimming water quality was worse last summer than in the previous year. 58 percent of all bathing sites monitored in 2010/11 exceeded bacteria levels considered "safe" for swimming on at least one occasion (see Testing and grading). That's up from 46 percent in 2009/10.
The Ministry for the Environment reckons the wet weather suffered by many regions last year is partly to blame for the poorer result. Rainfall causes more faecal matter to be washed from the land into the sea. As a result, bacteria levels in our swimming waters can skyrocket.
Tidal flows at coastal sites mean high bacteria counts are more likely to be short-term events. But that's not always the case. For the last 5 years, monitoring of water quality at Auckland's Laingholm Beach, French Bay and Wood Bay has found unsafe bacteria levels more than 30 percent of the time.
Freshwater spots are also more likely to return poor results. 64 percent of the 237 freshwater sites monitored last year had unsafe e.coli levels on one or more occasions. Many sites are on rivers and streams that run through catchments where dairy farming has been expanding.
Time bomb
Wet weather may be to blame for the poorer results seen last summer but other clouds are looming. Dr Kevin Parris of the OECD Trade and Agriculture Directorate made headlines in September when he predicted the full impact of our current farming practices on water quality may not be seen for another 30 to 40 years.
In the same month, Auditor-General Lyn Provost issued a report critical of freshwater management by some regional councils and warned "changes are needed sooner rather than later". In Waikato and Southland, where there's been major intensification of dairy farming, the report found councils were not doing enough to reduce "known risks" to water quality.
One of the most well-known risks is effluent from dairy farms. According to a Ministry of Agriculture and Forestry report, 16 percent of dairy farms nationwide have "significant non-compliance" with effluent-discharge rules. Waikato recorded the highest rate of non-compliance: 27 percent of dairy farmers in the region are failing to meet regional rules.
Water quality on the lower Waikato River has been found to be consistently "unsatisfactory" for recreation. The same goes for other waterways in the region – including those in Hauraki and upland Waikato. Monitoring by Waikato Regional Council also shows e.coli levels in the Waipa River are unsafe for swimming most of the time.
On target?
In May 2011 the government finally released a national policy statement (NPS) on freshwater. The NPS is a statutory document prepared under the Resource Management Act and sets high-level goals for freshwater management.
Regional councils have been given much of the job of achieving these goals. They’re required to set "water quality limits" for all water bodies in their regions and to specify targets to improve water quality. But they've got a generous amount of time to do it: 31 December 2030 is the date when the NPS has to be fully implemented.
The government acknowledges councils will need "guidance" and says further work is being done to support NPS implementation. There's hope the process will get a push from the Land and Water Forum (a grouping of environment, industry and iwi interests), which has been asked to provide advice on water quality.
Set up in 2008 by Minister for the Environment Nick Smith and Minister of Agriculture David Carter, the Land and Water Forum has previously recommended the development of binding national standards to tighten controls on contaminants entering our waterways. But the Government has yet to sign up officially to the idea.
Meanwhile, back in Waihi Beach the district council is applying to renew – for another 35 years – the resource consent that allows it to discharge wastewater from its treatment plant into Three Mile Creek.
Our view
- Poor water quality presents a very real health risk, particularly to young children and those with compromised immunity. It's also telling evidence of lax environmental management.
- The national policy statement on freshwater management is a positive step – but the timeline for implementation is generous. We agree with the Auditor-General that action needs to be sooner rather than later.
Testing and grading
Regional councils – and district councils in some areas – are responsible for monitoring swimming-water quality.
Coastal sites are tested for enterococci (levels above 280 enterococci per 100mls of water are considered “unsafe” to swim). Freshwater sites are tested for e.coli (levels above 550 e.coli per 100mls of water are considered “unsafe”).
Enterococci and e.coli thresholds are set in national guidelines and are based on an “acceptable risk” of getting sick. For coastal sites, the acceptable level of risk is set at 19 in every 1000 bathers falling ill; for freshwater sites, it’s 8 in every 1000.
Not every swimming spot around the country is monitored. Councils may also stop monitoring a site if testing shows water quality is either consistently poor or consistently good. Sites permanently unsafe for swimming should have a warning sign. Any spot may also be unsafe for swimming if it’s been raining. The risk of getting ill can remain high for several days after rainfall.
Swimming in polluted water can cause skin, eye and ear infections as well as cold- and flu-like symptoms. It can also cause nasty gastrointestinal diseases such as the one caused by campylobacter. Campylobacter has been found consistently in river-water samples.
Beach grades
National water-quality guidelines recommend that councils grade each of the swimming spots they monitor. These "beach grades" are based on long-term faecal-indicator counts and an assessment of a site’s susceptibility to contamination. They range from “very good” to “very poor”.
However, only some councils use the grading system. We've collected data from those that do (see Graded swimming sites). Grades were correct as at December 2010.
Only 20 percent of the 445 graded sites get the top mark of “very good”. Another 31 percent rate “good” and just over a fifth (23 percent) manage a “fair” grade. 26 percent rate either “poor” or “very poor” – most of these are freshwater sites on rivers and streams where water quality is compromised by agricultural and other land uses.
The 5 grades
- Very good: Satisfactory for swimming at all times and may not require monitoring on a regular basis.
- Good: Satisfactory for swimming most of the time. These sites are monitored throughout the summer; councils are meant to put up warning signs if water quality deteriorates.
- Fair: Generally satisfactory for swimming but have many potential sources of faecal material. Be cautious about swimming during periods of high rainfall - and don't swim if the water is discoloured.
- Poor: Avoid swimming. This applies especially to the very young, the very old and those with compromised immune systems. These sites are likely to have permanent warning signs, but the council may instead monitor the sites once a week and put up temporary warnings.
- Very poor: Avoid swimming - there are direct discharges of faecal material. The council is meant to put up a permanent sign that says swimming is not recommended.