Farmers in Chengde, Hebei Province,used to dam the Chao River in order to divert enough water for the irrigation of their rice fields. However, the river also contributes 40 percent of the water of Miyun Reservoir, one of the major sources of Beijing's water supply. To ensure that the capital has enough water supply, officials at city and county levels have to resort to persuasion, and when this fails, they are forced to have the dams pulled down.