Exploratory drilling has finally started on a water project in Wairarapa first mooted in the late 1990s.
The aim is to take some of the Tararua Ranges' 5-6 metres of annual rainfall to irrigate the district's flatlands, which are usually parched in summer.
It would use stored water behind a dam to more than triple the amount of agricultural land that gets irrigation and also offer recreation in lakes.
The organisation running the scheme, the Wairarapa Water Use Project, says it has started drilling at the two sites that could be used for storage lakes.
These are at Black Creek, in the Kaituna area west of Masterton, and Tividale in the Tauweru catchment north-east of the town.
The drilling is scheduled to take about two months to complete and will provide core samples for geotechnical assessment of the viability of building dams there.