Greens Senator Sarah Hanson-Young has said the Water Minister's suggestion to flood the lower lakes with seawater is a risky move at today's Adelaide hearing for the Murray Senate Inquiry.

"This is day two of hearings for this Inquiry, and already it is becoming evident that the option put forward by Water Minister Wong's Department of flooding the lower lakes with saltwater is risky," said Senator Hanson-Young.

"What effect will this saltwater flooding have on the groundwater of the Fleurieu Peninsula?

"The Government must carry out a comprehensive risk assessment before it even contemplates such an environmentally drastic option.

"Then the Government must be prepared to put its hand on its heart and tell the people that saltwater flooding is a safe option for South Australia's water security.

"Freshwater flows are what the lower lakes and Coorong need, and what the Greens will continue to campaign for."

Inquiry witness Professor John Williams from Adelaide University's Law School presented evidence stating that there were significant powers that the Federal Government could have referred to it by the states.

"The Inquiry has had confirmed that the Federal Government can and must do more," said Senator Hanson-Young.

"State borders and the politics that are played across them must be dissolved on this issue, for the sake of a responsible approach to a national environmental catastrophe.

"The Federal Government's constitutional Corporations Power should be referred immediately by the States."

Senator Hanson-Young also backed Professor Mike Young's call for an independent scientific expert to be appointed in charge of finding solutions to the Murray crisis.

"I will push for this Inquiry to recommend that the Government adopt Professor Young's suggestion, so there is one person in charge who will sift through all relevant scientific information and proposals about how and what needs to be done to best protect the Coorong and lower lakes," she said.

"Having this independent scientific expert with the focus and authority to get on with the job will help build community understanding and trust about the tough decisions that will have to be made to save our Storm Boy country."

For more information: Gemma Clark on 0427 604 760