Systems and methods for gasifying a feedstock are provided. A feedstock can be introduced to a riser. A first oxidant can be introduced to a first mixing zone within the riser, thereby generating a first high temperature zone within the first mixing zone proximate an entry point of the first oxidant. A first stream of water can be introduced to the first high temperature zone to reduce the temperature therein. A second oxidant can be introduced to a second mixing zone within the riser, thereby generating a second high temperature zone within the second mixing zone proximate an entry point of the second oxidant. A second stream of water can be introduced to the second high temperature zone to reduce the temperature therein. The feedstock and the first and second oxidants can be gasified in a gasification zone within the riser.