The city of St. Paul has begun to request ideas for how to redevelop the aging RiverCentre parking ramp in downtown.

This week, the city's Housing and Redevelopment Authority (HRA) issued a solicitation for private development proposals for the air rights above and land next to the ramp at 150 W. Kellogg Blvd., across the street from the St. Paul RiverCentre Convention Center and the Xcel Energy Center.

"Enormous potential for development exists adjacent to the RiverCentre campus and, through development, we will realize transformational vitality in downtown and across our great city," said St. Paul Mayor Melvin Carter in the solicitation documents publicized Wednesday.

City officials anticipate the chosen project could be designed to allow private development on top of or on the land next to the 1,600-stall parking ramp. The city is open to a variety of uses for the project, including housing, hotel, offices and retail.

According to solicitation documents, city officials would like a development that complements the convention center and surrounding businesses and incorporates the city's vision of a proposed 1.5-mile river balcony along the top of the bluff overlooking the Mississippi River.

"St. Paul is a city that embraces innovation, leans into sustainability, and seeks vitality and growth," said HRA Chairman Chris Tolbert in a statement. "This project is no different, and we stand ready to move forward with a partner that can creatively make our values a reality along Kellogg Boulevard."

The RiverCentre ramp was built in 1970. The ramp was closed for six months last year for emergency repairs after a slab of concrete fell from the ceiling and damaged a parked car.

Visit St. Paul, the convention and visitors bureau that operates the ramp, spent more than $2 million on repairs.

But the city hasn't been able to secure state bonding dollars to demolish and rebuild the ramp.

City officials have touted the 3.4-acre site's highway access, views of the Mississippi River from the bluffs, and the fact that the site is in a federal opportunity zone. After accommodating RiverCentre and downtown public parking needs, as many as 450 parking spaces in the ramp could be used for the private development, the city said.

However, the HRA says it doesn't expect public subsidies would be needed to help with the private development.

The HRA wants any reconstruction of the ramp to begin no later than the summer of 2021 with hopes it would open by fall 2023 and construction of the private development would happen at the same time or after.

Development proposals are due by Nov. 22.

Staff writer Emma Nelson contributed to this report. Nicole Norfleet • 612-673-4495 Twitter: @nicolenorfleet