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Published: 2010-07-07 00:00:00

Environment Waikato continues to make good progress through its policy development to do more to protect water quality in the region, says policy committee chair Paula Southgate.

"Our review of our Regional Policy Statement has been building on the good collaborative work among the council, farmers, industry, iwi and others to put in place strategies and actions to improve water quality."

Her comments follow a report from the parliamentary Commissioner for the Environment which placed the Waihou and Waipa in the top four of New Zealand’s most contaminated rivers. The report showed similar water quality pressures in other parts of the country.

"A new draft of our Regional Policy Statement – due for public consultation shortly – will specifically propose that we do more to protect water bodies of high quality and improve those which have become degraded like the Waihou and Waipa.

"The community in general places a high value of having good water quality, which supports key industries such as farming and tourism, as well as providing for recreation and protecting aquatic life.

"One possible way of doing more to protect water quality is a requirement to exclude cattle and deer from all water bodies to help stop sediment getting into rivers, a key issue for the Waihou and the Waipa in particular. This sort of riparian fencing also helps keep stock out of waterways, thereby reducing microbial contamination which can make people and stock ill."

Cr Southgate said extra Government funding for cleaning up the Waikato River, being made available through co-management with iwi, would go some way towards remedying water quality problems there.

But she added the new policies under development were also essential for making overall gains in the Waikato River and the region’s waterways in general. "With intensifying farming impacting significantly on water quality in places such as the Waihou and Waipa, another key to improving the situation will be working closely with the agriculture sector to limit how activities like dairying affect the amount of nutrients and sediment in water."

Nutrient leaching or run-off from farming operations can affect water clarity by stimulating the growth of algae, which can sometimes be toxic to humans and stock. EW monitoring shows an increase in the levels of the nutrients nitrogen (N) and phosphorus (P) in the majority of regional waterways, reflecting a national trend. Besides stimulating algae, particularly in the Waikato River, these nutrients can contribute to slimes and weeds. 

In some lakes, dead algae settling to the bottom can use up oxygen in summer causing fish and other animal life to either migrate or die. Water in the lower Waikato River can become green and murky because extra N and P in the stiller water of the hydro-lakes can create good growing conditions for various types of algae that then go down river. This "trapping" effect of the lakes can also result in blooms of both toxic blue-green algae and non-toxic diatom algae. Blooms do not occur in free-flowing rivers but in "impounded" waters such as lakes. In free-flowing waters, the types of algae that cause blooms are generally washed down to the sea.

Sediment from farming operations can also reduce clarity. Reduced clarity in turns affects recreational use of waterways and can impact on aquatic life. Some two thirds of regional river samples have previously failed to meet recreation standards due to reduced clarity because of sediment.

Under national guidelines introduced in 2003 some 31.4 per cent of sites other than the Waikato River were judged to have failed to meet contact recreation standards due to faecal contamination. Faecal contamination as a result of run-off after storms in the Firth of Thames means that shellfish can’t be harvested following the storms.

"These examples of the issues relating to water quality in our region show the problems are many and complex," said Cr Southgate.

"It’s only through the development of sound policies – backed by solid actions – will we make a difference.

"EW wants to work with all its partners in the community to deliver the improved water quality our community clearly wants.

"Farming has a key ongoing economic role in the region and we want to support that, as well as ensure we have a healthy environment, to meet the community’s expectations, and so that our natural resources continue to support our economy."

Cr Southgate said that as EW looked to solutions through the Regional Policy Statement process, there were things councils, industry and farmers could do now. These included ensuring ongoing full compliance with resource consents for discharges to rivers and keeping cattle out of streams.

Riparian planting by farmers was also encouraged to help prevent P run-off, while feed and standoff pads helped reduce the effects of urine and dung when it comes to degrading water, provided that they are properly sealed and the effluent treated.

Cr Southgate pointed to a New Zealand-first project from EW to help protect the very high water quality in the upper Waihou catchment as an example of what can be done. Fencing and tree planting there had helped protect the very clear water there. Another similar project underway is the Kaimai-Mamaku project.

"Over time, we could look to roll out more such schemes," she said.

EW was also continuing to work with farmers in trials in South Waikato aimed at helping cut nutrient leaching and run-off to waterways.

Commenting on the Waihou, which came in at second equal worst on the Parliamentary Commissioner’s list, Cr Southgate said some degree of discolouration of the Waihou as it heads to the sea is natural because of the countryside it passes through.

But she said the degree of decline of its overall water quality as it moved downstream was something the regional community would have to co-operate closely on to make improvements.

She noted the bulk of the nitrogen loading in the Waihou is predicted to come not from "point sources" – such as factories – but from land operations like farming, while a significant percentage of the phosphorus in the river also came from these "non point sources". This included nitrogen leaching and phosphorus run-off from farms, as well as farm effluent discharges to waterways.

The sources of the bacterium e. coli in the Waihou weren’t so clear but an EW e. coli guideline for "contact recreation" is exceeded at sites below about Matamata.

However, overall water quality of the Waihou River is mixed.

· the water is well-oxygenated

· levels of potentially toxic ammonia are low

· water clarity is excellent at and immediately downstream of Blue Spring, but is considerably poorer at Matamata and Te Aroha

· concentrations of the plant nutrients nitrogen and phosphorus progressively increase in a downstream direction - concentrations at Te Aroha are higher than many of those in rivers elsewhere in New Zealand (based on NIWA's national rivers programme)

· concentrations of e. coli also increase, with concentrations exceeding the swimming guidelines at Matamata and Te Aroha.

"Like the challenge presented by lifting regional water quality generally, making gains in the Waihou will require a big effort from all involved, such as councils, farmers and industry," said Cr Southgate.

"The fact that our waterways are a core part of our regional identity makes this sort of effort across the Waikato crucial for our collective future."