Harmful farming practices are being pointed to as a cause of the "disgusting" state of Hawke's Bay's rivers.
Although the Hawke's Bay Regional Council has said the Tukituki River is unlikely to be the source of the bacteria which caused around 5200 people to become sick, Tukituki Labour candidate Anna Lorck argues the gastro outbreak highlighted wider issues around water quality in the region.
Examples of this can be found down a country road near Waipawa, where animal carcasses and feedlots lie near the Tukituki River, and other streams.
Feedlots are an enclosed area where livestock are kept and fed. They are permitted, and only require consents if they do not meet certain conditions.
Although areas like these are "out of sight", Ms Lorck said, practices like these could be harming Hawke's Bay's rivers.
"We had the biggest wake-up call of any community in the country, and we're now dealing with a Third World problem," she said. "It's creeped up, all this intensification is going to come to a head. What's more important than safe drinking water, and swimmable rivers."
Environmental scientist Mike Joy said effluent from feedlots could contribute to waterway pollution.
"In feedlots, cattle compress the soil so much they make it absolutely impermeable ... it makes it like a big pan, so when there's rain the water will run straight off," he said, adding this did not take much rain.
The Massey University ecologist said effluent could also "leech down into the soil" after rainfall events, or it could seep deeper as cracks appeared in the ground after dry winters.
Feedlots close to rivers were more of a concern. In floods, it might take a river four hours "to get in proximity of effluent", but "that's nothing in the life of some pathogens", he said.
And on feedlots located on old riverbeds, effluents can easily move through the "porous" alluvial gravel.
However, Federated Farmers Hawke's Bay president Will Foley said it was a minority of farmers who operated feedlots, and there were policies in place to manage runoff.
Feedlots were run either as a system farmers chose to employ, or because of the way their farms were set up.
"If there is any indication or potential for effluent runoff these need to be dealt with," he said, adding this was being addressed through environmental plans, and the council's Tukituki plan change 6.
Mr Foley said farmers had been working to improve practices since water quality, and environmental impacts became an issue, and they would continue doing so. He said there were a number of different factors which could lead to the pollution of waterways - not just farming practices.
Labour's environment spokesman, David Parker, has also spoken out on the region's waterways.
"The state of Hawke's Bay's rivers is disgusting," he said. "It takes a lot pollution to render a river as big as the Tukituki unswimmable, but, because of the ineptitude by Hawke's Bay Regional Council, that has led to this."
Regional council chairman Fenton Wilson could not be reached for comment last night.
Mr Parker, who had experience as a water lawyer, had visited feedlots in the region and said he had absolutely no doubt they were contributing to the pollution of rivers like the Tukituki.
"They are cesspits, they don't have adequate ponding systems for runoff when you have a rain event, and there can be no doubt they are ruining your rivers."
A spokeswoman from the regional council said feedlots were a permitted activity but must meet the rules outlined in the Regional Resource Management Plan.
If a feedlot does not meet these conditions, a consent is required. The council does not monitor feedlots that do not require a consent.
"However if a consent is required for a feedlot then the feedlot will be monitored to ensure it is meeting the conditions of its consent. This may include the applicant installing monitoring bores above and below the feedlot," she said.
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