Barack Obama, John Bel Edwards

President Barack Obama and Louisiana Gov. John Bel Edwards tour Castle Place, a flood-damaged area of Baton Rouge, Aug. 23. Obama is making his first visit to flood-ravaged southern Louisiana as he attempts to assure the many thousands who have suffered damage to their homes, schools and businesses that his administration has made their recovery a priority. (AP Photo/Susan Walsh)

Gov. John Bel Edwards has increased the amount of federal money he thinks the state needs for flood recovery efforts — from $2.8 billion to $4 billion.

In a letter to President Barack Obama this week, Edwards said that the total impact of the catastrophic flood that swept across south Louisiana in August, killing 13 people and leaving thousands of homes damaged or destroyed, is becoming clearer as officials assess the damage.

“The federal government has been incredibly responsive to the needs of our state in the wake of two historic floods,” Edwards said in a statement. “However, FEMA now estimates that our unmet needs are greater than our initial request. Congress approved a down payment for assistance, and we are extremely grateful, but there are significant challenges ahead. Addressing our agricultural losses, rebuilding homes and businesses, restoring our infrastructure and strengthening communities to ensure this type of flood does not happen again are critically important for Louisiana’s future. I look forward to working with Congress and our congressional delegation after the election to give the people of Louisiana the assistance they need.”

Last month, Louisiana secured an initial $437.8 million in federal aid that officials have called a "down payment" on future assistance. Louisiana leaders are hoping to secure more aid when Congress returns later this year after the November elections.

Any additional funding will have to receive approval from Congress, but Obama has been an advocate of the flood aid, so Edwards' letter signaled to the White House that the state would be pushing for more.

"While the initial appropriation of Community Development Block Grants provides hope to those impacted and allows us to begin to address the housing needs of our most vulnerable citizens, it is inadequate to address the full range of housing, infrastructure and economic impacts that threaten to destroy many of our communities," Edwards wrote in his letter to Obama, which was dated Thursday and released to reporters on Friday.

FEMA has estimated as many as 188,000 structures, mostly homes, were flooded in August. The federal aid also extends to recovery efforts in north Louisiana that experienced floods in the spring.

The initial round of nearly $438 million in aid will come to the state in the form of semi-flexible HUD grants that will be used for programs that address the state's housing needs, as well as the needs of small businesses that are struggling to recover.

That money came through a last-minute agreement in Congress' stop-gap funding bill that prevented a government shutdown in September, but leaders have generally agreed that more money would be needed.

Edwards has appointed a 21-member task force to come up with recommendations for how the state will spend its federal funding. That task force has been studying potential recovery programs but has not yet revealed its plans. The state's congressional delegation has pressed on the panel to quickly come up with a plan that members can take back to Washington, D.C., when Congress returns from its fall recess.

Officials have estimated that the state suffered as much as $8.7 billion in damage from floods.

In his letter to Obama, Edwards also stresses the need for funding for mitigation projects that could prevent future floods, including $125 million for the Comite River Diversion Canal.

"If we are to rebuild the strong, resilient communities we all know need to rise from this disaster, we will need to make investments in water management infrastructure that will pay dividends for decades to come," Edwards wrote.

Follow Elizabeth Crisp on Twitter, @elizabethcrisp.