Effects of ecological factors and human activities on nonpoint source pollution in the upper reach of the Yangtze River and its management strategies

Abstract

Abstract. The effects of ecological and human activities on nonpoint source (NPS) pollution are key issues for sustainable water resources management. In this study, the Improved Export Coefficient Model and the Revised Universal Soil Loss Equation were adopted to estimate the annual loads of NPS pollutants during the period from 1960 through 2003 in the upper reach of the Yangtze River (URYR). Ecological factors and human activities affecting NPS pollution were distinguished and their respective effects were assessed. Variations of the dominant cause (between ecological factors and human activities) were presented. Furthermore, the combined effect of them on NPS pollution were successfully revealed. The results showed that the annual loads raised from ecological factors of dissolved nitrogen (DN) and dissolved phosphorus (DP) were relatively steady from 1960 to 2003. But those of sediment, absorbed nitrogen (AN) and absorbed phosphorus (AP) decreased during that period. In terms of the annual loads caused by human activities, those of dissolved pollutants increased from 1960 to 2000 and then fell. Those of sediment as well as absorbed pollutants peaked in 1980 and then decreased. Simultaneously, the dominant cause of DN loads shifted from ecological factors to human activities after 1980 while DP loads were mainly contributed by human activities. However, sediment, dissolved pollutants were primarily exported by ecological factors. Finally, strategies for managing anthropogenic activities were proposed and their effects on NPS pollution reduction were also depicted quantitatively.

Alarming nutrient pollution of Chinese rivers as a result of agricultural transitions

“…Comparison with other studies Some studies have already quantified N and P transport to waterbodies of the large Chinese rivers [56], in particular of the Changjiang River [9,15,46,[57][58][59]. A few studies exist on sub-basin analyses of the Changjiang River [9,15,59].…”

Influence Mechanisms of Rainfall and Terrain Characteristics on Total Nitrogen Losses from Regosol

“…In recent decades, a great deal of research concerning the influence of rainfall and terrain on NPS nitrogen pollution has been carried out worldwide [24][25][26]. A comparative study of the effects of rainfall events on the removal of NPS nitrogen determined the efficiency ratio indexes, load summation and load regression in the Kyeong-a stream basin, South Korea [27].…”

Long-Term Effects of Anthropogenic Factors on Nonpoint Source Pollution in the Upper Reaches of the Yangtze River

“…Therefore, it is also very important to further study the comprehensive effects of various anthropogenic factors on NPS, as well as their respective impacts, on a macro-temporal scale.The upper reaches of the Yangtze river [21], known as the green ecological barrier, is the catchment area of the Three Gorges Reservoir Region, and an important watershed in China. Its NPS pollution plays a vital role in the water quality of the Yangtze river [22]. In recent years, under the influence of anthropogenic factors and ecological factors, the water quality of the Yangtze river has changed greatly [23].…”