It will also focus attention on the intense battle between two landholder groups – Bald Hill/Wimpinmerit Catchment Group and Parrakie Wetlands Pty Ltd – to win the 'hearts and minds' of politicians to their cause.

BHW group spokesman Peter England says real science is being ignored in the face of baseless assumptions about wetland sustainability.

"We are concerned the lobbying and publicity generated by those opposed to completion of the scheme could lead to a no-drainage decision," he said.

"And that would be disastrous for the very wetlands those opposed to completion are fighting to save."

The Parrakie group argues that a proposed Bald Hill drain along the eastern boundary of the 720-hectare wetlands would effectively cut off the local catchment water and spark a massive decline of the ecology.

In particular, they believe this would adversely impact on the 20ha Rocky's Swamp, which is purported to have the highest open water Biodiversity Significance Index Score in the SE.

The other major sticking point focuses squarely on the depth of drains.

Director of Parrakie Wetlands Pty Ltd Patrick Ross, from Lucindale, in a submission to a 2005 Senate inquiry, said 70 per cent of landholders had originally wanted wide, shallow drains to help alleviate seasonal flooding.

"This cannot go on unchecked. There seems to be no system in place where the program has to be audited or any sort of reporting that should be in the public domain," he had said.

"The program continues to dig when there is a wealth of evidence that deep drains are not the panacea they are made out to be."

Politicians and bureaucrats, meanwhile, are grappling with the complexities of widely varying data that may influence a Cabinet decision - expected within a month - to proceed with or abandon the final stage of the project.

* Extract from a full Special Report in Stock Journal, April 30 issue.