Waterfront property is practically a must-have in Miami – so much that developers are nearly running out of waterfront land to build on. This demand for waterfront properties have led developers to eye Miami River – the city’s 5 ½-mile river that was once deemed a polluted, industrial backwater.

Times have indeed changed. With the economy strengthening and as prices for beach and Bayfront land soaring, developers have been snapping up the last riverfront plots.

For example, Integra Investments invested in two vacant river lots during the recession and flipped them at a profit of more than $21 million last year. Meanwhile, New York-based KAR Properties paid more than $60 million last year to assemble three vacant parcels on the river’s north bank west of the Miami Avenue Bridge.

Another major recent land deal include the $125 million that the family of Argentine grocery store magnate Alfredo Coto paid last year for a vacant property at 300 Biscayne Blvd. Way. Also of note is Related Group’s $104 million purchase of the office tower at 444 Brickell in late 2013. (Related has said it plans to build three towers on the site, called One Brickell, with 1,200 units.)

Developers are planning to build ultra-luxury condo towers with units at multimillion dollar price points near the delta where Miami River meets Biscayne Bay. The latest residential project, One River Point, is comprised of two 60-story towers designed by architect Rafael Viñoly that aims to bring ultra-luxury living as far west on the river. The 350 units will range from $850,000 to $12 million, with penthouses priced even higher, and start at $850 per square foot.

The towers will include the amenities that have become standard for Miami’s wealthiest residents: poolside café with butler service, private club with a media room and cigar lounge, and building concierge. In addition, private elevator landings and a robotic parking garage are also planned, along with an 85-foot waterfall near the site’s public riverwalk. The project, which has an address at 24 SW Fourth St., is scheduled to open in 2018.

One River Point’s second phase, on two lots set slightly back from the river, are slated to include a hotel, less-expensive condos, rental apartments and retail.

With all this activity, it’s no wonder that the Miami River Commission is estimating that a total of about 4,000 units are slated for development over the next few years, along with new hotels, restaurants and a mega-yacht marina. The promise of Brickell City Centre, a $1 billion mixed-use project with luxury shopping that is under construction between Southeast Sixth Street and Southeast Eighth Street on South Miami Avenue, is also luring developers to the river’s mouth.