Bas has been a senior scientist in water management since he started at IRRI in 1999. Up until September 2012 Bas was head of IRRI's Crop and Environmental Sciences Division and is currently the director of the Global Rice Science Partnership, the CGIAR Research Program for Rice. Bas developed water-saving technologies for rice such as Safe Alternative Wetting and Drying that can reduce water use by up to 30% without compromising yield.