UNY students do many activities to maintain the waters, one of which initiates Gerakan Pengoptimalan Sungai (GPS) activities in Semoyan village of Yogyakarta. GPS increases people's knowledge and awareness about the importance of maintaining the cleanliness of the river environment and local fish care. Youths put up banners regarding the ban on polluting rivers in some locations. This movement formed a community of environmental hygiene nurses in the river called the Gerakan Pengoptimalan Sungai (GRADASI).

There are many benefits of GPS. In the environmental aspect, after residents can maintain the river's cleanliness well, the river water can be clean so that fish can live again according to the ecosystem and safely as a playground for children. Furthermore, the surrounding residents can utilize it for watering fish farming ponds. From an economic aspect, when this program succeeds, fish will breed and become a source of income for residents. On the social part, the hope is to inspire other villages to manage and maintain the cleanliness of the river environment.