The Llanishen Reservoir development, submitted to Cardiff County Council last week, would leave more of the reservoir intact than the original plan and provide improved road access. But it still features plans for 326 homes, which campaigners claim would spoil the reservoir, part of the Nant Fawr wildlife corridor.
Llanishen Water, a project group formed by Western Power Distribution, has drawn up plans that include an enlarged sailing area and improved road access. The applicants say that the plans will turn 30ha of privately owned land into open space with wetlands and a wildlife centre.
John James, manager of Llanishen Water, said: "This proposal will provide a leisure resource for Cardiff without adding a penny to council tax bills."
But the Reservoir Action Group argues that the revised scheme runs contrary to council policies to protect the wildlife corridor. "It's not an appropriate place to build anything, let alone homes," said chairman Ted Thurgood.
"The enlarged area for sailing will be nowhere near big enough."