LANZHOU -- A spell of heavy rainfall has triggered floods in three rivers in Northwest China's Gansu province, local authorities said Sunday.

The province's water resources department said water has surpassed alert levels in Taohe River and Daxia River, two tributaries of the Yellow River, as well as in Bailong River, which flows into the Yangtze River, amid intense rain between Saturday and Sunday.

Gansu on Saturday initiated a Level II emergency response to floods, the second-highest in the country's four-tier emergency response system.

Rainstorms and floods have wreaked havoc in Gansu since Aug 10, damaging 721 km of levees, of which 2.5 km gave way to floodwater. Over 1.2 million people have been affected.

Zhouqu County, among the hardest hit by rain-triggered floods, on Wednesday activated a top-level emergency response for flood control and natural disaster relief. In its Qugaona Township, roads were damaged, electricity and communication were cut off and more than 2,500 people were urgently evacuated.

Zhouqu was the site of a devastating mudslide that left more than 1,700 people dead or missing in August 2010.