The Shooshan Company will give Arlington County $6.6 million to improve Mosaic Park in Ballston in exchange for being allowed to construct higher buildings at Founders Square.

By transferring development rights from the park to Founders Square, the county would allow the developer to increase the height and density of three of the five buildings it proposes constructing at the site. The tallest building will now be a 20-story office building. The County Board approved the deal at Saturday's board meeting.

Chairman Chris Zimmerman said the plan finally realizes the county’s goal of providing a high-quality park for the Ballston neighborhood.