The Herekawe stream – and those who live near it – can be glad that award-winning company Corteva Agriscience has such a highly developed environmental consciousness.

Corteva New Zealand, formerly known as Dow AgroSciences, is based in New Plymouth and is part of a company spun from merged company DowDuPont. It manufactures herbicides and insecticides and was recently honoured by the Taranaki Regional Council with an Environmental Leadership in Business award.

The company was recognised for consistently exceptional environmental performance regarding stormwater released into the Herekawa stream and its upgrade of its chemical storage area. The latter is where raw materials are stored prior to being moved to production areas, where they are mixed together to make herbicides and insecticide products.

Corteva Site Leader Dave Clarke says the upgrade provided significant improvements to the reliability and capacity of the storage area so it can contain rain water from a once-in-25-years storm.


"Although the previous chemicals storage area met regulatory requirements – and we've had excellent environmental performance – upgrading ensures we continue to prevent risk of environmental incidents," he says. "It was really good to be recognised for that in the Taranaki Regional Council Environmental awards.

"That's why we have gone above and beyond like this – not because of regulations, but because it's the right thing to do to ensure protection of the environment."

The finished products mixed in the production area are transferred to portable containers and distributed to customers. Any waste water from production is re-used or given to specialist waste disposal companies.

Corteva tests the stormwater before it leaves its Paritūtū site – to make sure it meets consent requirements and is quality enough for the Lower Herekawe Stream and coastal waters (it drains into the sea). The analysis is comprehensive – testing confirms no stormwater contamination before the water is discharged into Herekawe Stream.

Photo / Supplied
Photo / Supplied

The upgrade of the storage area means Corteva has now built in extra safeguards to its environmental management system, with the council impressed that the company sought the views of the local Ngāti Te Whiti hapū and consulted neighbours before starting on the latest improvements.

The boosted capacity of the stormwater holding area meant excavation near a wāhi tapu site. At the hapū's suggestion, the soil was used in landscaping and gardens on-site. Corteva has also helped establish the Herekawe walkway while staff take part in regular clean-ups of Herekawe Stream and New Plymouth's popular Back Beach, where the stream runs to the sea.

Indications are that what they are doing may be working – a check on the Herekawe stream's health on the Land Air Water Aotearoa (LAWA) website shows that water quality in the stream is trending up.

From a low point of a 2016 MCI score of 84 (a Macro-invertebrate Community Index measures the health of various organisms which live in the creek as a guide to water quality), the LAWA testing results show a mostly significant climb in quality, with a score of 102 in early 2019.


MCI scores are classified as 80-99 (fair ecological condition, water quality and habitat condition), 100-119 (good ecological, water condition and habitat quality) and over 119 (excellent conditions).

"Corteva is a new company but with 200 years of experience from its heritage businesses," says Clarke. "There is significant investment in R&D for our products, and there are strict regulatory requirements for production and use of our products."

That includes controls on where products can be made, raw materials that can be used, product analysis and what information goes on the label of the finished product — information including recommendations on buffer zones, distance from waterways and which crops to use them on.

An example of the R&D investment and products safe for waterways is one which Clarke says is used for the eradication of weeds around waterways and improves the viability of native species.