The project is situated in Parkstad, South Limburg, an administrative region consisting of 7 municipalities, formerly known as the East Mining Region. Deindustrialisation completely transformed the region, making it the first shrinking area of the Netherlands. Shrinkage commonly refers to a shrinking economy, shrinking population and increased urban vacancy. Deindustrialisation also caused serious aftermaths in terms of social problems. Many new urban park projects have been initiated to replace vacant housings and plots, these new parks also become ways to combat urban decay, poor social condition and crime rates. This huge need for parks is however seemingly difficult in a city that is already facing economic shrinkage. In the short run (or long run) where no new investment or residents can be expected in a shrinking area; parks rely only on government funding and appear as a losing investment or a financial burden. On the other hand, Parkstad faces an upcoming environmental threat of groundwater nitrate contamination which would not only impact drinking water and biodiversity but again, also lead to further financial burden for the government and for local residents. Nitrate problem is hard to tackle in the presence of intensified agricultural practice and Parkstad's signature soil type (Loess). The project questions the values of park, and more specifically the meaning of park in a shrinking city. It explores the possibility of marrying social restoration and nitrate remediation - two pressing needs of Parkstad, in the form of an urban park. The resulting design is on one hand a model of social-nitrate synergy through azolla (water fern), and on the other hand a park cooperative facilitating the azolla industry and the operation of an urban park. As a water-remediation and azolla-park prototype the project will also gain additional funding from research institutions, innovative start-ups and the water company. The designing of the Azolla City Park is an attempt to deliver such coexistence of the social layer and the functional nitrate-remediating layer of an urban park. It also aims to bring these multi-layer rhythms to life. The collective identity of the past is juxtaposed with the site's new function and identity. Azolla is the new coal, you may say. In the way coal mining used to give Heerlen its pride, businesses, social life and culture, so would the proposed azolla-city park create ripples of possibilities in the urban fabric of Heerlen.