Opponents of Trustpower's hydro scheme in Marlborough have launched a final bid to halt the $275 million project.
The Environment Court has begun hearing their appeal over Trustpower's 46km canal-based scheme which takes water from the Wairau River.
The scheme received interim consents two years ago and conditions were released by commissioners last year.
The main opponents, Fish and Game and the Save the Wairau group, say the Wairau River will be ruined by substantially reducing its water flow.
Trustpower has opened its submissions, saying no water would be taken at times of low flows and that the scheme's opponents have raised no new issues of substance in their appeal.
It has said six years of independent studies show a hydro scheme will not affect the river's health.
Pauline Doyle from the Wairau Valley Action group says at least two owners are refusing to let Trustpower on to their properties.
She says residents are planning to raise more money to fight Trustpower's scheme.
