Riparian management and the success of the Clean Streams Accord in Taranaki

September 2006
Taranakis 1965 dairy farms (used to be 2500 10 years ago), clustered around the base of Mt Taranaki (2500m asl), are bisected by more than 300 streams and rivers which flow off the mountain.

It is estimated that the majority of farms have stretches of waterway 4-6km long within their boundaries or forming part of the boundary. Nearly all farms have some waterway. While most of the bigger rivers have always been fenced to prevent stock wandering or drowning, smaller streams have in the past been left unfenced so that cows can gain access to water. Lactating dairy cows need a minimum of 15 litres of water per day and have been known to drink as much as 90 litres on a hot day.

However, access to streams creates water quality and landscape issues: coliform bacteria contamination, nutrient contamination, turbidity and bank damage. By fencing and retiring the banks of streams, and planting suitable sedges, shrubs and trees within the margin, the stock are excluded, surface water run-off is filtered and nutrients are taken up by plant roots, helping to create cleaner water in the streams. This also helps moderate flood flows and reduces the need for small streams to be mechanically cleaned.

Improved waterway margins also provide a better fish habitat, encourages the build-up of leaf litter for aquatic animals and shade which reduces the growth of nuisance plants in the waterways. Well-managed waterway margins are the last opportunity to keep farm pollutants out of the waterways.

In May 2003, the Dairying and Clean Streams Accord was signed by Fonterra Co-operative Group, regional councils (including Taranaki Regional Council), Ministry for the Environment and Ministry of Agriculture and Forestry. It is a statement of intent and framework for actions to promote sustainable dairy farming, by reducing the impact of dairying on streams, rivers, lakes, groundwater and wetlands.

Dairy cattle are to be excluded from streams, rivers and lakes by fencing, or where natural barriers prevent stock access. (not in Taranaki). Nationally, the goal is to exclude dairy cattle from 50% of streams, rivers and lakes by 2007 and 90% by 2012.

Where farm races cross watercourses regularly, more than twice a week, the goal is to have 50% of the crossings by bridge or culvert by 2007, and 90% by 2015.

Under the Clean Streams Accord, each region has the opportunity to develop further actions in recognition of their geographical differences. In June 2004 the Taranaki Regional Council (TRC), Taranaki Federated Farmers and Fonterra said that a regional action plan to implement the Accord would build on work already done by the Council and landowners since the early 1990s. A key difference for Taranaki is the addition of riparian fencing and planting, and the 90% implementation deadline extended by 3 years out to 2015. A key component of the regions water quality plan has been riparian management, and that would continue. Over 700 property plans on dairy farms had been prepared to that time. The services already provided by the council will continue, namely the survey and preparation of riparian management plans, which is done as a free service, and the provision of suitable native plants and trees, done at cost. The council contracts with local nurseries to supply in bulk suitable indigenous plants and passes on the savings to landowners implementing their riparian management plans.

The role of Fonterra is to gather information about the situation on its supply farms and work out ways to encourage suppliers to meet the targets set. Taranaki is the only region that supplies ground-truthed information on implementation of its plans to Fonterra.


During 2004-05 the TRC land management section surveyed 2239km of stream bank and prepared 381 riparian management plans. At the end of the financial year, the council had prepared a total of 1100 plans covering 6894kms of stream bank.

Therefore at 30 June 2005 approximately half of Taranaki dairy farms have riparian management plans and 55% stream banks covered by riparian management programme are fenced and 39% of stream banks have vegetation present (not all of it has been planted). This is understood to be the best achievement for any dairying region in New Zealand, and is ahead of the 2007 interim target date under the Accord.

Of the 750 farms monitored during 2004-05, 96% were found to have regular stock stream crossing with bridges or culverts, and this is ahead of the Accord target.

Also 66% of regionally significant wetlands are fenced, against a target of 60% fenced 2005, 90% by 2010.

Fonterra commented after the release of those figures that Taranaki shows there is steady progress in riparian management on dairy farms and this would indicate there is no requirement to regulate.


Two-wire electric fencing is around $2.50/m, including labour, which will keep cattle out of the riparian strip. Conventional seven-wire fencing would be up to $13/m and is not generally required in Taranaki. Planting is recommended as soon as the strip is fenced, to make planting easier, and to reduce potential weed invasion which will save on herbicide cost in the long run. Flexible plants like carex, toetoe and flax are recommended to establish in the immediate flood zone while other natives suitable for further up the bank include cabbage tree, coprosma, pittosporum, olearia, lacebark, pseudopanax and broadleafs. Where possible incorporating existing vegetation will cut down the cost of planting. The planting recommendation is based on fencing to a change in contour with spacings from 1.5 to 2.75m apart, depending on the final size of the plant . Fencing and planting could cost between $6-8 per metre for site preparation, materials and labour, planting and maintenance spraying, depending on the overall width of the margin. Plants are generally PB3 size and cost on average between $2.00 and $2.40. These costs can be reduced by half by doing the work yourself. Growing your own plants from seed or uplifting seedlings can also save money but requires knowledge and is time consuming.

Leighurst Farm

This is a 30-year-old dairy farm developed by Graemes father Miles Harkness from a sheep and beef farm, being one of the last along SH 3 to go to dairying. Miles also instilled in Graeme a deep love of native trees and the property has 25-30ha of virgin native bush which will remain undisturbed. A variety of native gecko has been discovered on the farm, plus a native orchid which is very rare.

The property is 151ha, 120ha effective, with a dairy herd of 300 cows. It has two boundary rivers (Mangamawhete and another Waipukuiti) and two substantial streams crossing the farm, having risen on the slopes of Mt Taranaki and flowing north-east to the coast at Waitara. The rivers were always fenced but the streams were not fenced when Graeme asked for a riparian management plan from the TRC in 2004. The total length of streambank within the farm is 2460 m, so 2460 m of fencing is required. Graeme believes he has made good progress on the planned fencing and planting, having done about 30% of the total proposed planting so far and 90% of the fencing is finished. He began using single electric wires, now two-wire electric fencing. Before fencing the cows had access to the streams, which meant bank erosion and the need for diggers to clear the channel.

The plantings have been carex, toetoe, flax and shrubs, plus large trees further back, like totara and rimu. Graeme pays tribute to TRC office Darren Scown, who has been advising Graeme for the past three years. Darren mapped the farm and drew up the fencing and planting plan.