Ecological engineering restoration of a non-point source polluted river in Northern China

River restoration is the re-establishment of a river to a state that is more reflective of its predisturbance form. To restore a river polluted by human interference, we conducted an ecological restoration study from 2009 to 2011 on parts of the Yitong River, which is a typical non-point source polluted river in Northern China. The engineering included three parts: riparian vegetation buffering strip (part 1); multi-functional ecological fishponds (part 2), and river channel enhancement zone (part 3). By monitoring and evaluating the pollution indices of the study area's inlet and outlet, we found that the ecological engineering could significantly enhance the reduction rate of NH3-N, COD, and BOD5, which had increased from −14.29%, 1.81%, and −0.5% before restoration to 66.29%, 10.81%, and 7.25% in 2011 (post-restoration), respectively. The diversity of planktonic algae became rich, and in particular the species number representing clean water increased from 1 before restoration (2009) to 8 after the restoration (2011). Our results indicate that ecological engineering can significantly reduce non-point source pollution and improve the water quality, biodiversity, and economic benefits, and it is therefore an effective scientific approach for restoring the integrity of the river ecosystem and achieving continuous social and economic development.