Research on the design of a buffer strip for nonpoint source pollution control in the Three Gorges Reservoir Area, China

Abstract:

Following the implementation of the Three Gorges Dam Project, nonpoint source (NPS) pollution has become a serious problem in the Three Gorges Reservoir (TGR). An urgent need exists to build buffer strips along the TGR to improve water quality. However, to design the optimal buffer strip for NPS pollution control is challenging because of spatial variations in topography, hydrology, slope and drainage patterns in the Three Gorges Reservoir Area (TGRA). This research focus on (1) plan the placement of buffer strip in the TGRA for water quality benefits using terrain analysis. (2) estimate suitable widths of buffer strip for different objectives of water quality protection to reflect regional variations in physical conditions.

Terrain analysis can provide assessments for placement of conservation practices. There are some ineffective areas where the performance of conservation practices is minimal at watershed scale. The results showed that with increased conservation objectives, greater widths are required to ensure NPS pollutant removal and improvements in water quality. The widths of the modelling buffer vary significantly in spatial with variation in pollutant concentration, slope and soil conditions. It is necessary to install buffer strip along the tributary streams for NPS pollution control and water quality protection at the watershed scale.