Impact of land-use changes in Liuyanghe watershed on non-point pollutant load

Key words: 
• Liuyanghe watershed /
• L-THIA land-use /
• non-point source pollution load

Abstract: Taking a typical watershed in hilly red soil region—Liuyanghe watershed as a case study, combined with the land-use of 1986, 2000 and 2005, soil and precipitation data, under the support of RS and GIS, the dynamic change of land-use was analyzed and the long term average surface runoff volume were estimated using L-THIA model. The results show that there is a significant trend of transforming from forest and grass land to urban, agricultural and rural residential areas, and from agricultural land to urban area. The agricultural areas increase from 13.75% in 1986 to about 20% in 2005 of the total watershed, and the urban and urban residential areas are changed from 1.34% and 0.10% in 1986 to 2.56% and 0.80% in 2005, separately, which make the sensitive areas of non-point source pollution expanding, and the pollution degree is more and more seriously from 1986 to 2005. The loads of TN and TP increase from 675.56 t to 1 001.02 t, 15.52 t to 23.41 t, respectively.