The Rock Island City Council unanimously approved a measure Monday night that paves the way for a new Walmart to be built on 11th Street.

The council authorized City Manager Thomas Thomas to proceed with final negotiations regarding the sale of about 20 acres where the Walmart will be built.

The agreement calls for Price Properties LLC, a development company working with Walmart, to pay $4.5 million to the city for the Watch Tower Plaza property and surrounding land. The vote, made without any comments from members of the public, allows Thomas to execute the contract documents and refer it to the city attorney for an ordinance.

The city will fund the cost of demolishing all the buildings on the lot, estimated to cost $10 million to $12 million.

Thomas said the store will bring in about $1.4 million in sales tax revenue and about $300,000 in property taxes per year. Over a 20-year period, he said that would be about $34 million in what he called a conservative estimate.

“This is something that will be a great shot in the arm,” he said.

Thomas said he believes Walmart and accompanying retail businesses that often are located nearby will be the start of economic growth in the entire area. “And this will be the cornerstone of it,” he said.

Watch Tower, built in 1962, was a major shopping destination for two decades until it closed in 1983. It was home to Zayre department store and an Eagle Food Center. Over the subsequent years, it has been home to various retail stores, some churches, a major bakery and Black Hawk College’s Adult Learning Center.

Thomas has said some of the first related developments to the south will be the development of city-owned land just southwest of City Limits Saloon and Grill. The property, which the city and developers had earlier hoped would draw Walmart, will become the new home to some of the displaced Watch Tower tenants.

Jeff Eder, the city’s community and economic development director, said the city is committed to helping the current tenants find new locations, either in the same area or other locales in Rock Island. Among the current tenants that have agreed to move to the city’s now vacant 7.5-acre site, west of 9th Street, is Black Hawk’s learning center and Christine Elsberg State Farm.

Thomas said they hope all demolition could be finished in June. If so, Walmart could be open by late fall 2013. Otherwise, he said the store would be completed sometime in 2014.