Company chief executive Andrew Newman said yesterday the changes did not affect resource consents for the project, currently being considered by a board of inquiry, because they were within the parameters the board was considering.
Mr Newman said he was happy with the 42 per cent uptake of available water indicated through the non-binding expression of interest process to date.
"I would argue in many ways it will be easier over time to do the next next tranche of uptake. Those customers committing now are committing to something that is not yet built. They can't see it, touch it, feel it - whereas once the pipe is running past a farm gate the water is there, it's easily accessed, people can translate the impact of that in a much more tangible way," he said. "Certainly the experience of [irrigation] schemes in the South Island is that once the pipe is there the uptake moves pretty fast."
The company last week announced it would charge users of the scheme 23 cents per cubic metre of water, a figure that was in line with expectations.
The company is continuing to finalise negotiations with construction consortium OHL-Hawkins to build the dam and is also awaiting the board of inquiry's draft decision on resource consents, due by April 15.
The company expects to present a business case for the $265 million project to the regional council before the end of next month. The council intends to invest up to $80 million.