Even if agriculture was removed and catchments returned to their natural state, 38% of the country’s rivers would still not meet national sediment standards, an independent review of freshwater quality standards has found.
The review by independent consultants Torlesse Environmental for Beef + Lamb New Zealand also found also found an estimated 44% of all sheep and beef farmland would need to be retired, along with other extensive mitigations, if the national bottom lines (NBL) for fine sediment were enforced.
And “even if these measures were taken, around 50% of the catchments currently below the NBLs would remain below them”, the report says.
The report notes that published literature indicates around 20% of waterways coming out of catchments in their natural state, for example National Parks, do not currently meet suspended fine sediment NBLs.
BLNZ chair Kate Acland is calling for urgent changes to the sediment and E coli attribute bands and NBLs, saying they are “flawed, they are not achievable, and trying to achieve them will decimate farming and rural communities”.
The government has extended the period for regional councils to implement the National Policy Statement-Fresh Water Management (NPS-FM) and has said it will amend it, but Acland said the measures are still place and many councils are continuing with their planning processes based on the current NBLs.
The farming body is recommending the suspended fine sediment attribute and 95th percentile E coli limit – when water quality is not compromised by E coli for 95% of the time – are removed as interim measures.
Acland said there is urgency to replace the NPS-FM with a more appropriate national framework for managing suspended fine sediment and E coli.
Sheep and beef farming can have an impact on freshwater quality and it needs to be managed, Acland said.
“However, the way this is currently being done has some significant issues and will have massive implications for our sector, so it’s vital we get it right.”
The review found that fine sediment NBLs were based on the impacts to a small number of indigenous fish species and brown trout, which are highly susceptible to sediment.
It noted the link between sediment and fish used to establish the NBLs is based on recent modelled sediment data rather than measured data and paired with fish abundance surveys beginning in the 1970s.
The review concluded that relationship has significant uncertainty.
The NBLs were also found to not adequately account for natural variability, as evidenced by the number of rivers with catchments in their natural state that would not meet them.
The inclusion of the 95th percentile statistics does not allow regional councils to exclude data collected during heavy rainfall and floods.
The report noted that most mitigations are less effective during high flow from heavy rainfall events, so it can be difficult to meet the requirement to improve from one E coli attribute state band to the next.
Equally, the minimum required improvement for E coli applies all year round, including winter months, during storm events and to all waterways, including those not suitable for swimming or other contact recreation.
BLNZ estimates meeting current NBLs for water quality would cost the NZ economy $3.9 billion a year in lower exports plus the impact of closed business such as processing plants, farm servicing businesses and rural communities facilities.
The cost of planting and additional fencing to meet these standards is estimated at $1.4bn.
“These are eye-watering and hugely concerning numbers for our sector, and for New Zealand,” Acland said.
“This review supports the urgent need for a fundamental rethink of the management framework for suspended fine sediment and E coli.
“We need to act before regional freshwater plans become operative on the basis of these flawed NBLs.”
