The park was built over the North River Wastewater Treatment Plant, which processes 125 million US gallons (470,000 m3) of wastewater every day during dry weather, and is designed to handle up to 340 million US gallons (1,300,000 m3) a day when the weather is wet. In order to minimize odors emitted by the plant, dedicated odor-control facilities have been installed at the plant, including $55 million in recent upgrades.[5] The plant sits on 2,300 caissons pinned into bedrock up to 230 feet (70 m) beneath the river.