Spatial-Temporal Comparative Analysis of Water Environmental Quality Features in Nansi Lake Basin

Based on monitoring data from 2006 to 2010,the surface water environmental quality features in Nansi Lake Basin were analyzed at temporal and spatial scale. The results show that the water quality in Nansi Lake basin has improved during the annual period, the wet period and dry period. In terms of CODCr and NH3-N, the proportion of water with quality of class I to III has increased, while the proportion of water with quality that was inferior to class V has decreased. The proportion of water with quality of class Ito III in NH3-N was lager than that in CODCr. The Nansi Lake basin water quality in the wet period was slightly better than that in the annual period, while the water quality in dry period was slightly worse than that in the annual period. Judging from the spatial scale, the water quality of control units in the west of Nansi Lake basin is better than those in the east of Nansi Lake basin. The control units of Guangfu River and Laoyun River in Jining were the most seriously polluted areas.