Abstract
Identification of the interactive responses of water quantity and quality to changes in nature and human stressors is important for the effective management of water resources. Many studies have been conducted to determine the influence of these stressors on river discharge and water quality. However, there is little information about whether sewage treatment plants can improve water quality in a region where river streamflow has decreased sharply. In this study, a seasonal trend decomposition method was used to analyze long-term (1996–2015) and seasonal trends in the streamflow and water quality of the Guanting Reservoir Basin, which is located in a semi-arid region of China. The results showed that the streamflow in the Guanting Reservoir Basin decreased sharply from 1996–2000 due to precipitation change and human activities (human use and reservoir regulation), while the streamflow decline over the longer period of time (1996–2015) could be attributed to human activities. During the same time, the river water quality improved significantly, having a positive relationship with the capacity of wastewater treatment facilities. The water quality in the Guanting Reservoir showed a deferred response to the reduced external loading, due to internal loading from sediments. These results implied that for rivers in which streamflow has declined sharply, the water quality could be improved significantly by actions to control water pollution control. This study not only provides useful information for water resource management in the Guanting Reservoir Basin, but also supports the implementation of water pollution control measures in other rivers with a sharp decline in streamflow.
Highlights
IntroductionRivers are the chief source of water supply for humans and freshwater ecosystems (Tang and Lettenmaier 2012, Vorosmarty et al 2010)
Identifying the interactive responses of water quantity and quality to changes in these multiple stressors is important for the effective management of water resources (Crossman et al 2013)
Statistical methods All the trend analyses of precipitation, streamflow and water quality were conducted with a generalized additive modeling approach: seasonal trend decomposition using loess (STL) (Cleveland and Cleveland 1990, Shamsudduha et al 2009)
Summary
Rivers are the chief source of water supply for humans and freshwater ecosystems (Tang and Lettenmaier 2012, Vorosmarty et al 2010). Studies in northern China showed that streamflow in a large number of basins had a significantly decreasing trend during the past decades (1950s– 2000s), and abrupt changes in streamflow mostly occurred between 1978 and 1985 (Bao et al 2012, Wang et al 2013, Xu et al 2014). This period corresponded to the beginning of China’s reform and opening up, when agricultural and industrial water use dramatically increased; this was considered to be the main reason for the decline in streamflow (Liu and Xia 2004, Xia et al 2014, Yang and Tian 2009). With increasing population and economic growth, water abstraction is likely to increase rapidly around the world (Heathwaite 2010) and streamflow decline will occur in more regions
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
