The Ha-Long Bay in Vietnam is a UNESCO World Natural Heritage Site, a tourist magnet and an important mining location at the same time. A research team led by Prof. Dr. rer. nat. Harro Stolpe, holder of the Chair of Environmental Engineering + Ecology, investigated how mining wastewater can now help to meet the increasing demand for water as part of the "WaterMiner" project and finally developed analysis and management tools for harmonized integrated water management and improved surface management.