Quoting from a 2008 Gainesville Times article, Barnes grilled Deal about supporting dams on the Flint River, a controversial proposal in thirsty south Georgia with its heavy dependance on agriculture.
Deal said he was simply seeking $10 million for a feasibility study for the river that flows through southwest Georgia.
"I'm not proposing that we build a dam. I think it's appropriate that we do a study to find out what the needs are," Deal said, suggesting that reservoirs could be built on the river's tributaries.
But Barnes, a former congressman, said the study was not of tributaries but of three possible dams on the Flint River itself.
"This is another example of just what I call 'Washington speak.' There must be a course up there that they tell you and teach you how to answer a question and never answer it directly," Barnes, a former governor, retorted.
Deal called on Barnes to explain which agriculture tax breaks he would eliminate as part of his plan to pay for education proposals by wiping out special-interest tax exemptions.
"We're in agriculture country here. There are some 26 special exemptions in sales tax for agriculture and commercial fishing. I want to know whether or not you are proposing that we remove those sales tax exemptions on these very important areas of our economy," Deal asked.
When Barnes said they would not be on his target list, Deal scoffed that the Democrat wouldn't be able to pay for all that his campaign was promising.
"That's interesting, it seems like the Democrats never understand that when you take away tax cuts it amounts to a tax increase," Deal said.
The televised debate Tuesday night was sponsored by WALB in Albany.
Both candidates said they supported a guest worker program to allow immigrants in the country legally to help with farm labor.
And they agreed that deepening the Port of Savannah would be a key economic engine for the state. Deal said he had fought for the project even though it lay outside his north Georgia district
"I have been one of those who has been willing to step out, even though it was not in my congressional district, and put my name on the line and say this is a project that deserves federal funding," Deal said.
But Barnes said Congress hasn't delivered on the project.
"There's some study money but not one penny (from the federal government) for the deepening of that channel," Barnes said.
"And one of the reasons is that we don't have the influence in Congress that we once did," Barnes said.
When it came to the tri-state water wars, both men calibrated their message to their south Georgia audience.
"We have to recognize that the Atlanta region has to solve its own water problems and not go south to try to find a solution," Barnes said, stressing the need for more conservation efforts and increased storage facilities for water.
Deal said he would keep "downstream users in mind" as part of the tri-state negotiations.
"I want them to be involved in the discussions. It is a river channel. It is a river basin and everybody in it has a vested interest and I'll make sure those interests are balanced," Deal said.
Barnes accused Deal of flip flopping on inter-basin transfers, a polarizing plan in which water would be taken from one river basin and moved to another.
Deal said he does not support the transfers and accused Barnes of twisting his words. "Mr. Barnes cannot get that right either and that's unfortunate," Deal said.
But Barnes - quoting comments Deal made earlier in the campaign - said Deal had changed his position
"I don't believe that we should go from one basin to another to solve the water problems," Barnes said
As they have in past debates, Deal and Barnes battled over ethics and negative ads. Deal sought to link Barnes to President Barack Obama. Barnes said the race was not about Washington but who was best equipped to run the state.
Deal and Barnes had met earlier in the day in Forsyth in a forum sponsored by the Georgia State Retirees Association.
At that forum, Barnes said he would support placing a small portion of the state contribution to the pension fund into higher-risk investments as long as state employees supported the move and the plan was actuarially sound.
"For a small percentage, so that you can add in a better yield, yes, I would approve of that if the state employees agree," Barnes said.
Deal was less enthusiastic.
"We should be very, very cautious about trying to play the latest schemes on the stock market," Deal said.
Libertarian John Monds did not attend either debate Tuesday.