THE worst flooding in 30 years in northern Nigeria has affected at least 300000 people, submerging hundreds of villages and putting thousands of hectares of farmland under water, authorities said on Wednesday. Niger State appears to be the area the worst affected by the flooding which began several weeks ago following unusually heavy rains. The rains swelled the Niger and Kaduna rivers which run through the state and last week authorities opened the flood gates of the Kainji Dam, saying that the water had reached critical levels. That sent flood waters surging across the Niger River flood plain.