Group 1 - Typhoon "Wipha" is expected to make landfall along the coast from Zhuhai to Zhanjiang, with a mountain flood disaster risk warning issued by the Guangdong Provincial Water Resources Department [1] - Areas with a high likelihood of mountain flood disasters include cities such as Enping, Maoming, Yangjiang, and Yunfu, with an orange warning indicating significant risk [1] - The water level of some rivers in central and southern Guangdong is expected to rise by 2-5 meters, with some hydrological stations possibly exceeding warning levels from July 20 to 21 [1] Group 2 - Key rivers to monitor include the Yingli River, Longmen River, and Nandu River, among others, as part of the flood prevention measures [2] - The Guangdong Provincial Water Resources Department has raised the emergency response level from IV to II in response to the typhoon threat [2] - As of July 19, all small reservoirs in the province are above flood limits, but the risks are considered manageable, and river water levels are below warning levels [3]