Making our rivers swimmable comes at cost of $217million a year

Thursday, 29 March 2018

Presently 71.2 per cent of the nation's rivers and lakes are swimmable. (File photo)

The cost of making 90 per cent of our rivers and lakes 'swimmable' by 2040 has been estimated at $217 million a year, most of which would be borne those living in rural areas and Auckland.

The costs were calculated by the Ministry for the Environment after the nation's 16 regional councils submitted their draft targets for meeting the National Policy Statement for Freshwater Management goal of having 90 per cent of rivers and lakes swimmable by 2040.

The distribution of the total cost of committed work across the different regions.

A swimmable lake or river has a low level of E. coli, which is used as an indicator of the risk to human health.

At present 71.2 per cent of the nation's rivers and lakes were classed as swimmable.

Total annual cost of rural mitigation in each region, by land use category.

The Ministry for the Environment's projected improvement in water quality for rivers (if all councils had already carried out their planned works). Yellow, green and blue figures are swimmable, red and orange are not.

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Regional councils had to make their draft regional targets public by the end of this month. Final targets must be made public by December.

The councils provided information on planned upgrades of point discharges such as wastewater outfalls, and scientists provided information on the effect of mitigation measures that could be carried out in rural areas, such as excluding stock from waterways, riparian planting and management of dairy effluent.

The cost of excluding stock was based on using two-wire electric fences on both sides of waterways to exclude cows (but not sheep). Riparian buffers were three metres wide and a row of native plants.

A recently released ministry report stated that modelling showed the swimmability of rivers and lakes would improve by 6.9 per cent to 78.1 per cent if all the councils' works currently planned or underway were in place now.

The cost of achieving this was put at $217.23 million a year. Of that, $135.08 would be borne by the rural sector and $82.15m by the urban sector.

The regions bearing the largest costs were Auckland (40 per cent), Canterbury (15 per cent) and Waikato (9 per cent).

'Auckland's costs represent the large proportion of New Zealand's population that live there, and their significant commitment to improve wastewater infrastructure. For Canterbury and Waikato, the scale and intensity of agriculture leads to their significant contribution to total cost. Both of these regions also possess substantial areas of land allocated to lifestyle farming,' the report stated.

The allocation of cost across the various sectors nationally is: sheep and beef (59 per cent), lifestyle farms (19 per cent), dairy (16 per cent), dairy grazing (3 per cent) and deer (3 per cent).

'The cost for sheep and beef farming is driven by the low level of stream fencing currently on this land, the expense of stream fencing on steep land where much of this land use is located, the need to invest in water reticulation following stream fencing to provide livestock access to water, and the large area used for sheep and beef farming in New Zealand,' the report said.

If sheep were to be fenced from waterways there would be significant extra cost, it said.

The ministry's deputy secretary of water, Cheryl Barnes, said it was important to note that the report was 'not a plan for how we will achieve the national target, rather it is information for councils to use when they talk to their communities about what their final targets should be'.

'The report tells us what we can expect based on information currently available about work currently planned or underway in each region. The intent of the report is to provide a starting point, to help communities understand what's planned and explore what more needs to be done to reach the national target,' she said.

Barnes said the 2040 target was challenging, 'and we did not expect at this point in the process to have everything in place to achieve it'.