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Significant improvements in lake but rules still needed

Monday, 9 September 2013 12:30 p.m.

Lake Rotorua’s water quality has seen significant improvements in recent times, but Bay of Plenty Regional Council says rules to reduce nitrogen losses from pastoral land use are still needed.

Regional Council General Manager Natural Resource Operations Warwick Murray said there were many positive things happening in the catchment to improve water quality in the lake. 

“Landowners and the community have accepted that substantial reductions in nutrient loss are needed and that much of this will need to come from the pastoral sector. Many farmers have already made significant changes to their farming practices to reduce their nutrient losses, and we are working very constructively with landowners and other stakeholders to develop the rules and an incentive programme needed to make the further reductions.

“We have also implemented some hugely successful in-lake initiatives, like alum dosing, to help give us some shorter terms gains in water quality,” Mr Murray said.

“We have seen significant improvements in water quality in the lake and we have for now at least, hit the water quality target that was set with the community. However, we cannot kid ourselves that we have solved the problem long-term. The science suggests that this improvement has primarily been achieved though in-lake interventions like alum dosing, and helped by climatic conditions,” Mr Murray said.

“The bottom line is that if we stop our in-lake interventions, such as alum dosing, lake water quality will decline again.

“Robust science and modelling has told us that we must get the nitrogen load down from the present 755 tonnes per year to 435 tonnes. It also tells us that the majority of this will need to come from reductions in nitrogen losses from farms in the catchment,” he said.

“There is no doubt that the needed reduction will come at a cost to farmers, but at the moment there are no rules to ensure that this cost is shared equitably and that everyone does their bit.  Rule 11 for Lake Rotorua simply stopped any increases in nitrogen losses from those occurring between 2001 and 2004,” Mr Murray said.

“We acknowledge and applaud those farmers who have changed the way they use or manage their land and have made nutrient reductions on their properties. We know that changes made on individual farms to date are unlikely to be anywhere near the magnitude required to reach the sustainable nitrogen limit and achieve a sustainable long-term improvement in water quality in the lake across the entire catchment,” Mr Murray said.

It would take time to make the changes needed.

“The nutrient reductions needed and the timeframe to reach them were agreed by Federated Farmers Rotorua, Lake Rotorua Primary Producers Collective and Bay of Plenty Regional Council when the Oturoa Agreement was signed in February,” he said. 

“This agreement set out the principles and processes that will be used to reach the nutrient reduction target. It also agreed to on-going reviews of the science to ensure our work is adaptive to any changes in knowledge,” Mr Murray said.

“Rules to reduce nitrogen losses are coming for landowners in the Lake Rotorua catchment. We are conscious of the economic impact our decisions may have on the agricultural sector, and are working to ensure these are minimised,” he said. 

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