He said people supporting the dam said yes, while those not in favour said the opposite.
When asked whether the deadline would be extended to allow more to sign up, he said: "HBRIC will do what HBRIC will do."
"Getting the farmers to sign up was always going to be the hardest."
Mr Beaven said the water would be expensive and farmers should have been consulted right at the forefront, and there would only be a small number of farmers who would benefit from the dam.
He said he had "grave doubt" about the number of jobs that would be created in Hawke's Bay if the dam did go ahead.
Mr Beaven said that he and some other councillors had personal concerns about the dam, but they all "robustly questioned the validity of it".
While water contracts are being accepted, work continues on finalising the dam design and extensive distribution networks.
In February, the geotechnical work undertaken to inform the design of the diversion tunnel was completed, which showed "good results for rock quality and possible programme timeline benefits", according to the statement.
The investment company also states work is well under way on their approach to an appeal by Forest & Bird of a High Court review which gave the go-ahead to a Department of Conservation land exchange needed for the scheme to proceed.
It said: "It is likely that acquiring the land will be done after financial close."