Kaiwaiwai wetland near Lake Wairarapa was created by the farmers who own the dairy farm Kaiwaiwai Dairies. It is the winner of a Morgan Foundation environmental award.

Wetlands are making a comeback in the Wairarapa.

After decades of draining low lying areas, farmers and the community are recognising their value. In some cases they are restoring them, in others creating them.

Two wetlands adjoining Lake Wairarapa have won awards from the Morgan Foundation, and are setting examples for other landowners to follow.

GERARD HUTCHING/FAIRFAX NZ Kaiwaiwai farmers Neville Fisher and Aidan Bichan, with Ian Gunn from the Greater Wellington Regional Council, and the constructed wetland.

The Kaiwaiwai and Wairio wetlands are part of the Wairarapa Moana wetlands project which was launched in 2008.

Kaiwaiwai is a constructed wetland on a dairy farm, while Wairio is 130 hectares of low lying land in the lower Wairarapa that was cleared for farming in the 1960s.

One of seven partners in 275-ha Kaiwaiwai Dairies, Vern Brassel, said he knew of at least two other farmers who were following their example.

At a cost of $55,000 - 25 per cent paid by the landowners, the rest by a diverse group of funders - the 0.75 ha wetland has tapped into the talents of partner/engineer Neville Fisher.

Others have put time and effort into planting and other work.

"The significant thing is that it's a controlled wetland with 10 litres of water per second going through it every day of the year, so you have an opportunity to monitor its effect through changing temperatures," Brassel said.

Up to half a tonne of nitrates a year were being removed by the wetland. At times the water that was coming out contained no nitrates.

Not far away, also on the eastern side of the lake, Ducks Unlimited, in partnership with the Department of Conservation, a number of charitable trusts, local schools and Victoria University, are restoring Wairio wetland.

Jim Law, who has swapped the corporate world for farming, is one of the Ducks Unlimited group.

"We are not a group of duck shooters, our primary focus is on restoring wetlands. Ten years ago we said to DOC 'let us restore Wairio'.

"Until then their attitude had been 'we are the folks who can sort out environmental problems', but that has changed," Law said.

Numbers of the rare bittern have doubled, while the uncommon royal spoonbill has made an appearance. Duck species are also benefiting.

Law said they hoped to divert a large volume of water from nearby farmland to flow through the wetland, which is an ephemeral one - wet in winter but dry in summer.

This would make it less ephemeral, and by the time the water finally arrived in Lake Wairarapa, it would be stripped of most of its impurities.

There were plans to create a walkway between the lake and the wetland to give people access to the lake, which at present was difficult.

A 2013 paper published by Landcare Research estimated that the value of New Zealand wetlands, in terms of reducing or removing farm-generated nutrients, was about $740 million a year.

The total value of wetlands for all purposes is about $8 billion a year.