The Upper Harbor Terminal in Minneapolis probably is polluted, it's bisected by rail and high-voltage lines that make parcels less attractive, and it will be expensive to redevelop, but the city now has a road map for doing so.

The 48-acre industrial site between the Lowry Avenue and Camden bridges represents the most ambitious bridgehead in the city's 15-year-old dream of reshaping its upper riverfront.

The terminal is a city port that's being phased out this year in favor of redevelopment plans that call for a business park with a strip of green along the river, containing a parkway and trails. A just-released plan for converting that ambition to reality over the next 30 years from consultants working for the city's development agency now goes to City Council members for briefings.

It doesn't recommend a specific split of business and park uses for the site but outlines several scenarios as examples that give an idea of a timetable and the cost.

"They're test fits, just scenarios. Probably the reality will not be like any of them," said Ann Calvert, a city development official.

But the examples give the most concrete sense yet of the site's possibilities and the costs of making it attractive to developers. The scenarios estimate public costs for roads, parks and other infrastructure investments that range from $14 million to $22 million, not counting off-site street improvements. Calvert said the agency has a budget to continue more specific studies in 2015 to further determine the site's needs.

Cost is one obstacle. The area was used for truck farming until the port was built in 1968, but its role for trans-shipping commodities, including grain, coal, gravel, fertilizers and metals, leaves city officials assuming it will need at least modest soil cleanup. Studies of that haven't begun.

Another obstacle is that it's generally a long, skinny piece of land. The site is split by a CP Rail line running north-south and by a parallel high-voltage line closer to the river that serves Xcel Energy's Riverside power plant. The plan calls it feasible to move the power line next to the rail line to create bigger parcels that might be more attractive to developers. It estimated a cost for that of about $2 million. Xcel said it had no immediate comment because it lacks sufficient details.

The city hopes to attract job-intensive light industry or office development. The number of jobs depends on how intensively the site is developed, whether parking is in ramps or lots, and how much space is allocated to parkland, but the conceptual examples suggest at least 1,300 people could work there.

The proposed initial preparation of the site would include moving the power line, extending Dowling Avenue N. to the river and creating a public attraction there, deciding whether to keep the port's sea wall or let the bank go natural, cleaning and grading unused portions of the site, and determining whether to use a large warehouse for interim storage.

Much yet to be settled

A key issue yet to be resolved is whether some of the buildings and commodity-handling structures on the site should be preserved as historically significant and re-used in some fashion. Another is how wide the park corridor will be on the river edge of the site. All scenarios call for larger park areas on the north and south ends of the parcel, with a thinner corridor wide enough for at least a parkway and trails connecting them, and eventually linked to downriver parkways. Park Board President Liz Wielinski wants a briefing for her board, and said a Park Board priority is making sure there's space for people to play.

The plan envisions creating some form of destination where Dowling meets the river, such as an interim art park, a concession like the popular Sea Salt restaurant at Minnehaha Park or a restaurant on a floating barge.

The City Council several years ago decided to close the port at the end of 2014 to advance the upper river plan, which calls for trails, parks, housing and light-industrial job centers along the river north of the Plymouth Avenue Bridge. The closing decision preceded a congressional decision to close the Upper St. Anthony Lock and Dam no later than June 10 to hamper migration of invasive carp up the river. The port buildings and concrete pads are expected to be used for storage and shipping for several years.

Steve Brandt • 612-673-4438

Twitter: @brandtstrib