The significant restoration of the natural riverbed of the Cheonggyecheon River in Seoul, South Korea, and the urban revitalization of its surroundings are a brilliant example of Sustainable Urban Drainage. This deconstruction is based on the premise of renaturalization, which aims to restore the pre-development water balance (increasing concentration time and reducing peak runoff) through high permeability. It also demonstrates the undeniable importance of preserving valley floors and Permanent Preservation Areas (APPs) in Brazil, as defined by the Forest Code.