The problem with the Reid Park Zoo’s expansion has always been one of valuation.

Building the expansion has obvious costs, as the city and the zoo both recognize. But the public park land sacrificed for the expansion is given no dollar value.

That was true when the zoo was going to expand into Barnum Hill and the south duck pond, and it’s true now as the city chooses between two other alternatives.

The city finds itself in the position of choosing between one expansion option that appears to cost a lot of money — at least $15 million — and another that appears to cost a lot less, about $4.6 million.

Between those two, the choice is easy — you pick the cheaper one. That’s what City Manager Michael Ortega recommended to the Tucson mayor and council Tuesday — that they choose “Concept D” among the eight options discussed by Tucson residents in a wide-ranging listening session over the last six weeks.

Option D, though, means taking up to 4.5 acres of green and open space north of the duck ponds in central Reid Park. It’s a wide, grassy area with trees around its perimeter and a small baseball diamond in one corner. It has value, especially in a city as deficient in park space as Tucson is.

Opponents of the initial expansion proposal gathered on the edge of that acreage at noon Tuesday to promote their preferred option — Concept G. Under that option, the zoo would instead expand to the east and north, taking over what is now “hardscape” — buildings and blacktop closer to Randolph Way. No open space would be lost, but it would cost a lot more money.

Members of the group called Save the Heart of Reid Park argued the cost is skewed because the green space is considered free.

“This is given no weight at all because there’s no price tag on it,” said Michael McCrory, president of the nearby San Clemente Neighborhood Association.

What he means, of course, is that acreage was given no dollar value in the city’s analysis. So losing up to 4.5 acres of green and open space appears to cost only what design and construction of the expansion costs, not what the lost park costs the public.

Now, it’s hard to put a dollar figure on the value of those acres, when their value is so intangible — the joy of running around, playing a game, flying a kite, laying in the grass, breathing the air. But I asked an experienced Tucson appraiser what a possible market value would be.

Steven Cole, owner of Southwest Appraisal Associates, described two recent appraisals he performed of relatively comparable open space in Tucson. They were near roads, platted and with utility access, so easier to develop than this Reid Park parcel would be. He valued them at $6 to $9 per square foot.

This Reid Park parcel would only be developable for residential use, he deduced, and with the lack of platting and access to utilities, it would probably fall under the value of the previous appraisals he made. That could put it in the $3.50 to $5 per square foot range, he estimated, though he of course has not done an appraisal.

If you do the multiplication, you’ll find that adds up to between $686,000 and $980,000. Not a ton of money, but not really reflective of what the open space is worth to the public, either.

McCrory, Michelle Crow and others led a group after the press conference on a walking tour of the area where they would like the zoo to expand. The key, they pointed out, is all of its underutilized hardscape.

The Therapeutic Recreation Center on Randolph Way — not the Edith Ball Adaptive Recreation Center — would have to be moved. Everything else is a jumble of parking and a maintenance yard used by city parks.

“It’s just a poor use of space,” said Crow, a member of Save the Heart of Reid Park. “I don’t know why the city storage yard is sacred space.”

Indeed, these under-used areas are what the city ought to be exploiting in the zoo expansion and the reimagining of Reid Park. Unfortunately the zoo’s planned expansion into Barnum Hill and the south duck pond — now scotched — happened before a new Reid Park Master Plan could be developed.

Now a new master plan will be developed more or less at the same time as the new zoo expansion plan, assistant city manager Tim Thomure told me. And he confirmed that using the maintenance yard and parking lots is one of the key considerations for the long run.

In fact, he noted, even Concept D could make use of some of these city parking lots and work spaces, rather than taking the full 4.5 acres of open and green space.

“If you step out of the immediate environs of the zoo and you look across Reid Park, there’s a lot of opportunity to rethink and reconfigure how Reid Park flows and what kind of services it provides,” Thomure said.

“Whether we go with D or G, there’s consequences. If you go with G, you’ve used up a lot of resources to solve the immediate zoo expansion without affecting open space. If you go with D, you have a lot of financial resources remaining to be able to do other things.”

Those other things, he suggested, could include ideas like freeing up a fenced-off baseball field for public use.

However they solve the puzzle, the city should abide by a few guidelines: Open and green space has a high value not reflected in construction costs; the city’s inefficient uses of potential park land can be sacrificed; and there should be no net loss of public park space.

Follow those, and we could end up with a good solution to what looked a few months ago like an unsolvable conflict.

Reader poll (expanded): Which plan to you think is best for the Reid Park Zoo?

The Tucson City Manager has made his recommendation, which is not the same as the choice of the nonprofic group, Save the Heart of Reid Park, but costs less.

You voted:

Today the Reid Park Zoo celebrates the birthday of Penzi, the African elephant, who is one year old. This not-so-little elephant has captured the imagination of the community as she splashes in her mud wallow, gobbles up hay, and follows her big sister Nandi around to learn how to be an elephant. Video courtesy of Reid Park Zoo.


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Contact opinion columnist Tim Steller at tsteller@tucson.com or 520-807-7789. On Twitter: @senyorreporter