JOURNAL OF NATURAL RESOURCES ›› 2015, Vol. 30 ›› Issue (7): 1197-1209.

• Resource Evaluation •

### Spatial and Temporal Variations of Agricultural Non-point Source Pollution in the Three Gorges Reservoir Area of Chongqing

ZHANG Guang-na1, SHAO Jing-an1,2, WANG Jin-liang1, NI Jiu-pai3, XIE De-ti3

1. 1. College of Geographical Science, Chongqing Normal University, Chongqing 400047, China;
2. Key Laboratory of Surface Process and Environment Remote Sensing, in the Three Gorges Reservoir Area, Chongqing 400047, China;
3. College of Geographical Science, Southwest University, Chongqing 400715, China
• Received:2014-04-28 Revised:2014-08-23 Online:2015-07-20 Published:2015-07-14

Abstract:

According to the investigation on the pollution sources of chemical fertilizer, organic manure, Crops straw, breeding, aquiculture, dormitory sewage, dormitory wastes and soil erosion in the Three Gorges Reservoir Area (TGRA) of Chongqing, the spatial and temporal features of agricultural non-point source pollution (NPSP) were analyzed with the ArcGIS software. Spatial and temporal variations of the absolute discharge amount of NPSP in the TGRA of Chongqing were analyzed at the districts (counties) level using the spatial cluster and hot and cold spots analysis methods. There were three major findings from the study: 1) Moran' s I Index values remained high from 2005 to 2011 (although with a downward trend in 2008). 2) The results showed that the absolute discharge amounts of COD, BOD5, TN and TP from NPSP were 158.5, 73.5, 55.0 and 9.7 thousand ton per year in 2005. The absolute discharge amounts of COD, BOD5, TN and TP from NPSP were 109.3, 64.5, 56.0 and 10.4 thousand ton per year in 2008. The absolute discharge amounts of COD, BOD5, TN and TP from NPSP were 146.7, 86.8, 69.4 and 11.4 thousand ton per year in 2011. The absolute discharge amount of COD, BOD5 experienced a trend of raise after a drop, but the absolute discharge amount of TN and TP always showed upward trend from 2005 to 2011.3) Judging from the results of the hot and cold spots analysis, the inner section of the TGRA of Chongqing was the hotspots, whereas the metropolis' core district at the end of the TGRA of Chongqing was the cold spots. The primary pollution districts (counties) were Yunyang, Wanzhou and Kaixian, which all locate in the inner section of the TRGA of Chongqing. The study provided the scientific basis for the evaluation of NPSP in Chongqing.

CLC Number:

• X502