Analysis Of The Pollution Characteirstics Of The Agircultural Drainage Into Lake Bosten

Located in southern Xinjiang region, Lake Bosten is China’s largest inlandfreshwater lake. Since the1950s, the expansion in cultivated farmland areas has leadingto an environmental degradation mainly due to the significant increases on agriculturaldrainage to the lake. Therefore to deepen the understanding of pollution characteristicsas well as master its pattern became to the core for investigating the pollution treatmentscheme.Based on the agricultural drainage monitoring data of the basin of Lake Bostenfrom June2002to May2003, this report has combined the GIS plotting for26maindrainage canal sketch maps, the farmland withdrawals were calculated, and the drainagepollution sources were analyzed. During the analysis processes, single factor indexmethod was applied to investigate each drainage ditch’s water quality classificationcombined with the application of standard method of pollution load to analyzing itsmain pollutant. Following this, the treatment scheme was therefore made according tothe pollution’s seasonal variation trends. Based on the research mentioned above,several results were gained as Shown below:1. The total drainage volume was430million cubic meters. Drainage distributionsto yellow area, lakelet and to the large Lake were240,160and30million cubic metersrespectively.2. The main drainage pollution contribution was made by agricultural pollutions.The minor contributor was industrial wastewater and domestic wastewater, having atotal distribution of1%out of overall agricultural drainage pollution in volume.3. All wastes into the lakelet area were determined to be agricultural pollutions.This is also the main pollution resource for the large lake area. Situations in the yellowarea became much more complicated, as the pollution resource has included bothagricultural pollution, industrial pollution and domestic pollution. 4. It was determined by using single factor index method that the water qualitygoes to the yellow main dry line, combined with the water goes to22nd south dry lineand Shengli dry line has the worst water qualities, which were classified to a V-class.5. The standard method of pollution load has shown that total pollution load ratiofrom the yellow main dry line, south dry line and Shengli dry line was77.8%, which isthe main contributor to the drainage pollution in Lake Bosten area. Among these threepollution resources, the yellow main dry line has made the most significant contributionto it with a largest pollution ratio.6. It was determined that three main pollutants for drainage pollution were totalphosphorous, chemical oxygen demand and biochemical oxygen demand where thechemical oxygen demand was the main contributor.7. The seasonal variation on agricultural drainage has a general increasingtendency for spring and summer and during the winter the drainage decreased.