Less than five years ago, Fishers opened a $1 million amphitheater behind City Hall, proclaiming it the linchpin of a revitalized Nickel Plate District and announcing a series of free summer concerts.

Since then, economic activity has boomed downtown around the Municipal Center, with two large apartment buildings, restaurants, high-tech businesses and free music.

Now the city wants to spend $6 million more to expand the stage, add a green room for performers, new bathrooms, covered seating areas for spectators and spaces for food trucks.

The renovations are intended to handle bigger crowds at the park, known as Central Green, for concerts and make it more comfortable and inviting when there is not an event.

“There is a desire to utilize Central Green for more robust community events, to reinforce the sense of community, to enhance the experience of events for attendees, and to make these events appealing and accessible for all residents,” the bid solicitation reads.

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Mayor Scott Fadness said the expansion is needed because of the growing number of people drawn to the park for events.

"The crowds are so big that bathrooms are in short supply," Fadness said.

The space now is a stage and a lawn with no permanent seating that hosts several concerts and farmer’s markets each summer. More than 8,000 tickets have been given out for a July 7 concert by Loverboy, and 4,000 people regularly attend the Saturday morning farmer's markets, Fadness said.

The city's 2040 master plan includes upgrades for the park. Master plan consultant RQAW, Carmel, suggested concepts such as a sunken gathering space and shelters and a pavilion where residents could eat lunch. The added structures would ring the edges of the park.

City Councilwoman Selina Stoller, whose district includes the Nickel Plate, said she favors improving the park, but the council would have to weigh whether the cost merits it.

“There are definitely benefits to nearby businesses when we have these concerts that draw 7,000 people,” Stoller said. “And a better park, conceivably, will attract even more people.”

The park improvement is the third big-ticket public amenity put into motion in Fishers this year.

In February, Fishers, Noblesville and Hamilton County announced a $9 million plan to replace the Nickel Plate railroad with a walking and biking trail. In May, Fadness said he wanted to buy property at Geist Reservoir at Olio Road and 116th Street for $9 million to build a park and beach.

The emphasis on public spaces comes after years of Fishers stressing commercial growth, the most recent being the openings this fall of the Ikea,TopGolf and Portillo’s at I-69 and 116th Street.

Stoller said funding for all the greenspace projects would need to be examined closely.

“Is the price tag right? Where is the funding coming from? Can we do it without raising taxes?” she said.

Fadness said the beach, rail and amphitheater would be financed through bonds, which the council would need to approve.

Fishers collected offers from six developers before June 15, narrowed the field to four and has interviewed those candidates, Fadness said. The city will choose one by Sept. 1.

The amphitheater this summer has hosted several free concerts with big-name acts from years past, including Smash Mouth and John Waite. The stage size would be increased to accommodate more elaborate set designs and lighting, and the performers would have a room to stay and change before concerts.

RQAW designed the existing amphitheater, which was built in 2012.

The stage was built with a railroad motif as a nod to the nearby Nickel Plate rail line. But the bid request says a design link with the railroad isn’t required. Fadness has proposed tearing out the Nickel Plate rails so the trail could be built.

Call IndyStar reporter John Tuohy at (317) 444-6418. Follow him on Twitter and Facebook.