XI'AN - Northwest China's Shaanxi province plans to invest 6 billion yuan ($952 million) this year to fight floods and pollution in the Weihe River, the longest and most polluted tributary of the Yellow River, local water resources authorities have said.

The investment, part of the province's 18-billion-yuan fund earmarked to build water projects in 2012, will be used to widen dikes and counter pollution as well as plant trees on river banks and build or renovate bridges, Zhang Yuzhong, deputy director of the provincial water resources bureau, said Wednesday.

Last year, the province also spent heavily to build dikes along the river, which helped protect the region from the 2011 flood -- the biggest one in 30 years, Zhang noted.

The 818-km-long Weihe originates in Gansu province and flows past major industrial cities in Shaanxi, including Baoji, Xianyang, Xi'an and Weinan.

Despite years of efforts to curb the problem, the river has been seriously polluted over the past two decades as a result of waste discharges from paper mills and other highly polluting plants.