"It has been a long, hard-fought campaign by residents of the Mangatarere Valley, and hopefully it demonstrates that collective action can influence an outcome," he said.
According to the project organisers, Black Creek and Tividale between them could irrigate almost 30,000 hectares in an area north of Masterton and southwest of Greytown to the north of Lake Wairarapa, and provide water for other uses.
Storage reservoirs would be in the Kaituna area, west of Masterton, and the Taueru catchment, northeast of Masterton respectively. Black Creek incorporates a smaller option, Wakamoekau, which has the potential to be a standalone scheme.
The Black Creek dam would be built on land in the vicinity of Falloon Settlement Rd, west of Masterton, which was once bought up in anticipation of a dam for electricity generation that never came to pass.
It is now all back in private ownership.
The Tividale dam would be east of Masterton, on land in the vicinity of the old Bideford School.
Project chairman Bob Francis said no major flaws had been identified in any of the options that had been investigated and all of them would have been affordable.
"But some schemes had large overlaps in their distribution areas and choices had to be made based on that."
The Wairarapa Water Use Project spent four years investigating how water could be collected, stored and distributed for irrigation, power generation, municipal water, and environmental, recreational and cultural use. It aims to improve long-term regional prosperity while promoting sustainable management of land and water.
The pre-feasibility phase broadly compared schemes on financial, engineering, social, environmental and cultural criteria in order to narrow the options down.
The three other schemes considered - Te Mara, Mangatarere and White Rock Rd - have been discounted. Three others previously kept in reserve have also been discounted.
Mr Francis said that since 2010 the project had involved wide community interests through several dedicated advisory groups, representing iwi, business, environmental and recreational groups, as well as local and central government.
"Their feedback and input into project design and decisions has been hugely valuable."
An independent study last year concluded that irrigating an extra 30,000ha would add $157 million of GDP to the greater Wellington region a year and create 1200 jobs. A further $90 million in GDP would be added and more than 1100 jobs created for one year as a one-off result of farmers converting to irrigation.
The one-off effects of scheme infrastructure construction and any spin-off from new processing of primary produce would be additional.
"We understand the environmental challenges of increased irrigation and changing land use, and also how to make a scheme affordable to users.
"On the other hand, there are opportunities to help improve the resilience, efficiency and reliability of the Ruamahanga catchment water resource.
"These and other questions are highly complex but that does not mean solutions can't be found by working as a community, and that is the approach we will continue to take," Mr Francis said.
Wairarapa Water Use Project director Michael Bassett-Foss said construction costs had been estimated within a range that reflected the "pre-feasibility" stage of investigation. Independent experts estimated the net present cost of building the Black Creek scheme at between $138-$205 million, and Tividale between $71-$105 million.
"Importantly, these cost ranges do not translate directly to the price of water to users or the cost of a scheme to investors.
"We have provided the cost estimates for transparency purposes but a great deal more work is needed before the real cost of water is known," Mr Bassett-Foss said.
He said there was more work to be done and it needed to be determined in an 18-month study whether the schemes were feasible.
The study will cost about $4 million and will be funded jointly by Greater Wellington Regional Council and the Government, through the Irrigation Acceleration Fund.
In a separate project the Wairarapa community, through the Ruamahanga Whaitua Committee, is working on values and needs around freshwater.
Over the next year, a legal framework will be created for management of freshwater, which will become part of Wellington Regional Council's natural resources plan.
