Response of groundwater chemical characteristics to ecological water conveyance in the lower reaches of the Tarim River, Xinjiang, China

The purpose of this study was to determine the chemical characteristics of the groundwater and their changes in response to ecological water conveyance along a cut‐off river section in the lower reaches of the Tarim River, Xinjiang, China, during the intermittent ecological water conveyance between 2000 and 2007. Data were collected at 33 monitoring wells in nine sections in the lower reaches of the river. The results show that the groundwater quality improved continuously with increasing numbers of ecological water‐conveyance episodes. Longitudinally, the changing trend in groundwater salinity within the river reach was approximately W‐shaped. The two peak values appeared in the Tugmailai section in the middle and in the Kaogan section in the lower part of the river reach. Transversely, the changing trend in groundwater salinity showed obvious salt accumulation in the groundwater 750 m from the river channel. The groundwater salinity within 750 m of the river channel was relatively low and it did not change greatly. The groundwater salinity decreased along both sides of the river, which favoured the restoration of the riparian vegetation. These results also demonstrate a significant correlation between the height of the groundwater and groundwater salinity. The groundwater salinity was relatively low and the vegetation cover was greater than 30% in areas of groundwater level of 4–5 m. Copyright © 2009 John Wiley & Sons, Ltd.