Developers are breaking ground on Louisville’s RiverPark Place project after years of delay. Project leaders say the development of the mixed-use community will roll out in phases over the next decade and will depend on market demand.On Monday, Mayor Greg Fischer joined developer Steve Poe (pictured) who announced the first phase of the revitalized waterfront project located north of NuLu or the East Market District.“I think this is quickly going to become one of the hot spots in the city,” said Fischer.Construction has now begun on 150 boat slips expected to be finished by next April and 166 apartments expected to be completed in the first quarter of 2013. The cost of phase one is $25 million.The decision to proceed with the project is based on new financial partnerships as well as interest in Louisville’s downtown area from renters, said Poe.“In the Louisville market I believe that the occupancy rate right now is around 96.5 percent for upscale apartments,” he said.Poe is close. Downtown’s rental occupancy is around 93 percent, which is higher than it’s been in nearly a decade, according to data from Louisville Downtown Management District.Condo sales have not had the same consistency, which may be why Poe said he’ll likely test the condo market later next year.“We think ultimately sometime next summer we’ll probably test the condo market to see if that’s coming back and then we may start condo building the following year,” Poe said.The 40-acre project includes a mixed-use community of retail stores, restaurants and office space, which will be developed over the next ten to twelve years depending on market demand, Poe said.