Four towers supporting an open-air shelf that stretches across the edge of St. Paul’s downtown to the river’s edge: That’s the third and latest plan for Riverfront Properties, where the former home of West Publishing, Ramsey County offices and the county jail once overlooked the Mississippi River.

The proposed development, which would double the size of Ramsey County’s six-acre project to include another six acres of airspace owned by the Canadian Pacific Railroad and the city of St. Paul, received largely positive feedback from Ramsey County’s board during a workshop Tuesday.

The county board recommended that its staff begin negotiations with AECOM, a Los-Angeles-based developer with local offices, for the project, which has yet to be given a price tag.

Over the next six months, county staff will work with the developer not only to come up with a price, but also to further explore the feasibility of what is the most ambitious proposal for the site to date.

AECOM’s proposal beat out nine other developers, and three other finalists, after the county put out a call for plans last November.

The rough site — running along the river bluff to where Kellogg Boulevard meets Wabasha Street — is now wide open, after seven buildings were torn down there.

Highlights of the new proposal include:

• Four mixed-use towers with offices below and living spaces above, and restaurants and retail at the street level.

• Proposed heights of the office towers were roughly detailed. One would be 24 to 36 stories and a second between 12 and 20. The other towers would include 250 to 350 apartments, a 150- to 250-room boutique luxury hotel, and 80 to 150 condominiums.

• Below the street level of the bluff, the plan envisions between 1,500 and 1,800 parking spaces.The plan also calls for extending and sloping Market Street downhill to connect to Shepard Road at the base of the bluff.

THE VIEW’S THE THING

Developers repeatedly touted the shelf as the highlight of their presentation: a slight, walkable slope that would leave 45 feet of clearance above the Canadian Pacific tracks, with such features as a bandshell and shaded areas to sit to watch the now-adjacent river, several dozen feet below.

“That’s one of the drivers we cannot lose … making sure you still see that vista,” said Jim Thomson, vice president and regional cities leader for AECOM.

Commissioner Blake Huffman focused on a key phrase that appeared repeatedly in the developer’s packet: “depending on market demand.”

“How dependent is it on the market?” Huffman asked, noting that the Twin Cities had seen some good years in the residential market, and may perhaps be due for a dip.

“There is tremendous residential growth (in the east metro),” replied AECOM’s Brian Dusek, adding, “I don’t see that stopping anytime soon.”

Thomson said his company was hoping to secure anchor tenants for the office towers — companies to take up a third to even half of the towers’ space.

Commissioners largely expressed hope for the plan.

“This is the first time I really got a good sense that the developer realizes the potential of this site,” said Chairman Jim McDonough.

FINANCING QUESTION

But the plan has a long way to go. In 30 to 60 days, the board will vote on a preliminary development agreement. Within six months, they hope to iron out details such as costs and timelines, conduct traffic, parking and utility studies — and determine how much the public will pay for.

When the topic of tax increment financing came up, commissioners repeated their desire that there be none.

In particular, Commissioner Rafael Ortega stressed that he told the developer that there would be “absolutely no TIF” when they sought proposals. “They’ve been working with that.”

When asked how the county might chip in funding in other ways, Ortega mentioned tax abatements, as had been done for a county project in suburban Lino Lakes.

The heads of two St. Paul city departments — parks and recreation and public works — were in the audience.

Public works head Kathy Lantry said she didn’t see anything in the proposal that set off alarm bells.

“The vision is extraordinary for downtown,” she said.

After years of failed efforts to market the site to the private sector, the county spent $17 million to clear the river bluff in an attempt to draw a private developer. Than an elaborate $225 million redevelopment plan led by a Phoenix-based developer fell through last summer.

The county has built a retaining wall along the bluff, completed last November. That same month, the county sent out another proposal request for developers.

The site has been off the tax rolls since 1992, when West Publishing moved to Eagan. The former West buildings were later converted into government offices, but the county moved out of the facility in 2013. The jail was closed in 2003.