The Hai River is a significant waterway in northern China, flowing through the cities of Tianjin and Beijing. It is approximately 1,000 kilometers long and serves as an important source of water for agriculture and industry in the region. The river is part of the larger Yellow River system and plays a crucial role in the local ecosystem. Historically, the Hai River has been vital for trade and transportation, connecting various regions. Its basin supports a diverse range of wildlife and is home to several cities that rely on its resources. Efforts have been made to address pollution and improve water quality in recent years.