By William C. Shelton

(The opinions and views expressed in the commentaries of The Somerville News belong solely to the authors of those commentaries and do not reflect the views or opinions of The Somerville News, its staff or publishers.)

Two weeks ago the mayor’s staff submitted an updated Union Square Revitalization Plan to the Board of Aldermen. It would commit the city to hundreds of millions in property acquisition and public-improvements investments over the next twenty years.

The plan builds on 2009’s Union Square rezoning, and on this year’s Comprehensive Plan for the city. Those planning efforts are exemplary for their process, products, and the shared vision that they hold out.

But the Aldermen and the Somerville Redevelopment Authority will most likely conduct a hearing on the Revitalization Plan within this coming month. That seems like a brief period for Somerville’s citizens and taxpayers to adequately absorb what’s in the 100-page document. So I would like to ask some questions and get the conversation going.

The plan accurately identifies “the reintroduction of light-rail transit as the single most important contributing factor to Union Square’s revival as Somerville’s downtown.” Indeed, it was light-rail that transformed Union Square into Somerville’s commercial center a century-and-a-half ago.

Prior to that, dairy farms, stone quarries, and brickyards dominated the area. Then, the first horse-drawn streetcar in Greater Boston began service in 1852 and ran between Union Square and Harvard Square. The light rail network continued to expand throughout the rest of that century and was electrified in the first decade of the 20th century. People could now live up to six miles away from where they worked, and still commute within an hour.

Somerville became one of the first of Boston’s “inner suburbs.” When it changed its charter from a town’s to a city’s in 1872, it had fewer than 15,000 residents. By 1910, more people lived here than do so today.

The rails could bring workers to Union Square as well as taking them to Boston. So the surrounding area industrialized.

The largest meatpacking company in the Eastern U.S. located where the Somerville Avenue Target store is today, employing 1,000 workers. The Boynton Yards area was stockyards. S. Armstrong and Co. made barrels. On Washington Street, 300 workers in the I.H. Brown & Co. mill operated its state-of-the art drying equipment.

Electric trolleys glided down Somerville Avenue, Washington Street, and Summer Street, making 88 stops per day in Union Square, where stores, eateries, and personal services establishments proliferated to serve the swarming residents and workers. Legal, insurance, accounting, real estate and financial professionals leased upper-floor office space. Locals called Bow Street, “Doctors Row” because it was where healthcare professionals maintained what we now call “live/work space.” And the Somerville Journal did serious reporting from a building on the corner of Bow and Walnut Streets.

The potential to emulate the economic elements of this evolution was one of the motivations that brought ‘Villens, the mayor, aldermen, our legislative delegation, the business community, and smart growth advocates together in a unified and successful movement to bring the Green Line to Union Square. And that leads to my first question. If regional transportation authorities are legally obligated to extend the Green Line, why has the city committed to take the land for the station?

I’m not aware of a precedent where a municipality has acquired land for the T. So could this be some kind of extortion to shift financial risk onto the city? Just askin’.

The risk comes first from the possibility that the actual costs of an eminent-domain land acquisition may be greater than expected. The Revitalization Plan’s Stage One involves acquiring the land along the East side of Prospect Street, from the rail line to Somerville Avenue.

Implementing Phase One would require issuing $8 million in bonds, $6 million for property acquisition, relocation, and demolition, and $2 million for completing 25% of the infrastructure design.

Any owner of land that the city takes can argue in court that the compensation he or she receives is inadequate. Juries have an unpleasant history of sympathizing with such plaintiffs and awarding unrealistically generous judgments.

The city would assemble the properties north of the station into economically viable parcels and sell them to private developers. So the city would become a land speculator.

This is not necessarily a bad thing. As the regional economy evolves, Somerville will inevitably be well positioned to become a business destination. If market forces created strong demand for such property, the city could make a nice profit.

But the market forecast today is uncertain at best. Nor does the city have deep pockets. We rely heavily on net state aid, which has dropped from $57 million in 2002 to $30 million last year. And our cash reserves are thin.

Sixteen months ago, I wrote a column questioning whether the city’s issuing bonds to support the Assembly Square District Improvement Financing scheme was too risky. But with that plan, developers were in place and offering financial guarantees if their projects did not hit specific milestones by dates certain. We have no such developers for Union Square’s North Prospect Block at this time.

The plan anticipates building a new central library in a “Civic Center Block” where the Public Safety Building is now located. We learn that the city is on the waiting list for an $18 million dollar construction grant from the Board of Library Commissioners. The plan suggests the possibility of building a new city hall there as well.

A rationale for these moves is that foot traffic generated by such civic facilities would simultaneously expand Union Square’s retail and services markets. But similar attempts elsewhere across the U.S. have shown that most visitors to public offices do not transform into comparison shoppers, and only a few become convenience shoppers.

One need look no further than Central Square. Locating civic offices there had little effect on the commercial district’s business. But the University Park mixed-use development had a substantial impact.

And while municipal buildings generate no tax revenue, they can displace higher valued developments that do.

Would the central library serve the entire city better in Union Square than where it is now? Would the city lose its $18-million place in line if it didn’t build a library in Union Square?

In addition to the seven parcels in Phase One, the plan lists 27 parcels that would ultimately be acquired throughout the revitalization district. Total acquisition costs are projected at $26 million; relocation costs, at $5.3 million. Most remediation costs would be borne by developers.

Public improvements costs for Phase One alone would be $60 million. In recent years, a rare confluence of events brought Somerville remarkably good fortune in winning state and federal infrastructure funding. Do we believe that this winning streak will continue? Why?

The selection and proposed uses of the acquisition parcels make perfect sense to me from an urban planning and revitalization perspective. But what happens if things do not go as well as hoped for? At what points can we modify the plan, once the Commonwealth has approved it? How do we not get in over our heads?

Union Square is my neighborhood. I would love to see the Revitalization Plan’s compelling vision fully implemented. But I don’t want to put the city’s fiscal health at risk.

There may well be reassuring answers to all of my questions. I look forward to hearing them.