The spatial and temporal characteristics of water quality in Bosten Lake

Bosten is the largest inland freshwater lake in our country，which is located in the arid region. Based on the monitoring data of 17 fixed sampling points in the great lakes area from 2000 to 2017，this paper analyzed the dynamic change characteristics of the water quality in nearly 18 years，and studied the spatial distribution of 8 water quality index by using Ordinary Kriging interpolation，and then discussed the correlation of these index by using Pearson correlation test. The results showed that :（1） In 2000-2010，the content of 8 water quality index increased， and water quality deteriorated. However，the water level gradually decreased，the water quality index decreased year by year. BOD，DO，TP reached Ⅰ class standard by 2017；NH3-N reached Ⅱ class standard；Permanganate index，TN reached Ⅲ class standard；CODMn reached Ⅳ class standard，and TDS was brackish water.（2） Through the Pearson correlation analysis，the correlation of TP and TN was significant negative（ P<0.01），the correlation of NH3-N and TN was extremely significant positive（ P<0.01）.（3） By Ordinary Kriging interpolation，the spatial distribution of water quality in Bosten Lake was extremely uneven. The content of water quality index was higher in northwest and southeast，while the content was lower in central and southwest. Based on this，this paper suggested changing the outlet of Bosten lake to improve the water circulation.