An Environment Canterbury-commissioned report, conducted by the Institute of Environmental Science and Research Ltd (ESR), released today highlights two main sources of faecal contaminants in Christchurch’s Avon River/ Otakaro.
The report, a joint project of Environment Canterbury, Christchurch City Council and the Avon-Heathcote Estuary Ihutai Trust, used innovative faecal source tracking technology to look at the sources of elevated concentrations of Escherichia coli (E.coli) in the Avon River. E. coli bacteria are found in human, animal and bird faeces and high concentrations in waterways indicate an increased risk of disease in humans.
Environment Canterbury’s Director of Investigation and Monitoring, Ken Taylor, says the report provides valuable information about the sources of these contaminants in our waterways, and will assist Environment Canterbury, Christchurch City Council and the Christchurch public in the future management of Christchurch’s water quality.
“The report shows at low flows or after rain, the primary contributors of E. coli to the Avon River are wildfowl and dogs,” he says.
“When it’s dry, the main source of faecal contaminants in the Avon River appears to be wildfowl. When it’s wet, dog faeces appear to be a much more significant factor,” he says.
“Ministry of Health guidelines recommend that freshwater recreational areas should have less than 260 E. coli/100ml. Water measurements in the Avon River regularly exceed 260 E.coli/100ml and in many cases reach levels of 550 E.coli/100ml and above.
“Before rain, E. coli levels of up to 540 E.coli/100ml were measured in the Avon River. Immediately after rain, E. coli counts in the Avon River increased up to 3600 E. coli/100ml,” he says.
Monitoring was conducted during the period of March to May 2009, with water samples being taken at two locations – Kerrs Reach and the Antigua Boat Sheds. There were no sewage overflows during the study and human faecal pollution was only detected at the Kerrs Reach site during very heavy rainfall.
Mr Taylor says knowing the source of contamination in the Avon River will help us to manage those sources and implement measures to safeguard Christchurch residents and the environment.
“What this report means is that dogs and wildfowl pose a significant problem to the health of our waterways,” says Mr Taylor, “and a potential health risk to people who use the rivers for recreation.”
“Dog owners need to be encouraged to pick up dog faeces, especially along river banks, and home owners could consider implementing measures to reduce or eliminate contaminants at the source, which could be achieved by designing and installing stormwater systems to treat stormwater at the source.
Mr Taylor says Environment Canterbury in conjunction with Christchurch City Council, ran a two month public awareness campaign in June to help make Christchurch’s waterways healthier.
“Let’s change our ways to change our waterways” was a campaign to raise public awareness around the role the community could play to make the city’s rivers and streams healthier - simple actions like washing your car on the grass, not the driveway, or picking up your litter and dog droppings, would all have a positive impact.
Mr Taylor says research tells us people want to be involved, they value clean streams and rivers and want to take actions to improve the health of Christchurch’s urban waterways. The Avon is one of Christchurch’s greatest natural assets and the ESR report confirms that what we do in our backyards and parks certainly impacts upon the health of Christchurch waterways.
Christchurch City Council City Environment General Manager Jane Parfitt says "this research is one of a number of initiatives where CCC and Environment Canterbury are working together to improve the quality of the city's waterways. By understanding what is causing this contamination we are better placed to look at how it might be managed."
The report is available at www.cleanwaterways.org.nz/research.html or
http://ecan.govt.nz/get-involved/local-projects-community-groups/avon-heathcote-estuary-ihutai-trust/Pages/faecal-source-tracking-avon-river.aspx
For more information contact:
Environment Canterbury
Ken Taylor, Director Investigation and Monitoring
Phone: 03 371 7109
Mobile: 027 295 4359
Christchurch City Council
Jenny Ridgen
Programme Manager Healthy Environment
Phone: 9418407
ESR
Dr Brent Gilpin
Phone: 03 351 0044