JACKSONVILLE BEACH — When Christa Savva returned to the Sandy Shoes Beach Resort a day after Hurricane Matthew brushed by Melbourne Beach, she looked at the beach in front of the pink-flamingo-colored hotel and noticed that half the sand dunes had disappeared.Savva guesses three-quarters of the missing dunes washed into the ocean, and the remaining quarter scattered onto the Brevard County resort's beachfront property, which was undamaged by the hurricane last week."I was like, 'Oh, my goodness!' " Savva, a property manager for the hotel, said Sunday. "It's crazy to have the dunes gone and all you see is empty space." The sand on Florida's beaches is the equivalent of tourism gold, and its disappearance over time threatens the state's No. 1 industry. While Matthew didn't ravage Florida's coast as a series of storms did a dozen years ago, it collapsed dunes, washing away sand that protected buildings and roads during storms, and will likely require the spending of millions of dollars on beach restoration projects.President Barack Obama is declaring a major disaster in Florida following the damage from Matthew, meaning that the state can become eligible for additional federal aid.But Gov. Rick Scott said Sunday that the declaration was limited to help with debris removal and emergency protective measures. That means the state will not receive aid for individual assistance or for funding to help with government buildings and roads.Matthew scraped along Florida's eastern coast and caused beach erosion, power outages and flooding, and was responsible for at least four deaths. State officials said that as of midday Sunday, there were nearly 423,000 people still without power.Scott said in a statement that Florida sustained "significant damage" and that he will continue to submit requests to the federal government for additional assistance.Federal, state and local officials respond to beach erosion by depositing new sand in areas where it has disappeared, and the sand dunes such as those in Melbourne Beach act as barriers to infrastructure. Before these projects took off three decades ago, seawalls were often the only thing that stood between water, winds and buildings during storms."The good news is a lot of people don't realize our beaches are engineered. It looks natural, but we construct the sand so it's sacrificed during hurricanes and protects roads and structures and potentially human lives," said Jackie Keiser, a Jacksonville-area official with the U.S. Army Corps of Engineers.While a statewide evaluation of beach erosion has yet to be completed, individual Atlantic-coast counties from south of the Space Coast up to the Georgia border were assessing the lost sand.A $13.5 million project to replenish Jacksonville-area beaches with 650,000 thousand cubic yards of sand over seven miles was under way before Matthew. Keiser said she is certain that same amount of sand was lost from the hurricane and the amount of sand needed for the project will likely double. Virginia Barker, the natural resources director for Brevard County, the area of Florida often referred to as the Space Coast, said the erosion from Matthew appears to be more in the category of Hurricane Sandy in 2012 than a devastating series of hurricanes of 2004 and 2005. After Sandy, 2.4 million cubic yards of sand were needed to replenish 14 miles of Brevard County's shoreline. The replenishment was far smaller than what was required after Hurricane Frances and Hurricane Jeanne made landfall just south of the Space Coast a dozen years ago."This is world-famous Cocoa Beach. People come here for the sandy experience," Barker said. "It's tremendously important to our economy. The alternative is to allow erosion and let the sea go up and there will be no sandy beach."In Melbourne Beach, now that half of the dunes are gone in front of the Sandy Shoes, the high tide can lap up to the steps that lead to the hotel's wooden deck overlooking the beach."There's still a beach, and everything … but it's just a lot flatter," Savva said. "High tide is something you're going to have to watch out for now."