Following the flood in the late 1990s in northeast and south China, the PLA formed some dedicated disaster relief forces. These troops are composed of engineer, bridging, and other support units.
Equipped with special equipment such as pontoon bridge, mechanical bridge, boats, etc, these units are specifically designed to deal with flooding as well as other natural disasters. They have high readiness and can be deployed in very short time.
Not only would this help reduce the human and material losses in time of crisis, it is also a very good method to practice these units’ rapid response/deployment capabilities. After all, there is no much difference between building a pontoon bridge for disaster and for a military operation.