Hydro and Agro Informatics Institute (HAII), National Institute of Metrology (Thailand) (NIMT) and Department of Disaster Prevention and Mitigation (DDPM) are collaborating to establish GNSS reference base stations in the flood risk area to initiate the pilot CORS network in Thailand .A GNSS reference site will be positioned at the NIMT and also nominated to the global network of International GNSS Service (IGS), while the other sites will also follow the IGS guideline. Next the existing stations at the DOL and DPT will also be upgraded and integrated to this pilot CORS network. This initiative not only will benefit Thailand for numerous applications (e.g. rapid surveying, city planning, and evaluating efficiency of current and future flood protections), but also will be a foundation of precise mapping in the future. Eventually an effective water management could be achieved.