Marsh Park, a spit of land along the banks of the Los Angeles River, will serve as both a recreational space and a filter for garbage that would otherwise end up in the water. Storm runoff will be naturally filtered through a large, grass-covered water detention basin. From there, the water will seep slowly through the ground, which will separate it from trash and other debris before it reaches the river. Previously, such runoff would flow straight from the streets to the river, carrying whatever garbage it collected along the way.