Progress has been made in the study of hydrological connectivity and its water environment effects in arid inland river basins

Hydrological connectivity refers to the material exchange, energy flow, organic matter transport and movement process with water as the medium under certain climatic and dry and wet conditions, which will be affected
by the hydrological continuity between the composition, structure and pattern of geographical units.
The dynamic changes and transformations of hydrological connectivity will lead to changes in the hydrodynamic conditions of rivers and lakes, which will have a linkage impact on water quality, water ecology and water environment conditions and trigger feedback, which will directly affect the quality of water environment, ecological security of wetlands and the stability of ecosystems, and ultimately lead to the degradation and loss
of the structure and function of river and lake systems.
The fragmented water system structure of the inland river basin in the arid zone is sensitive to the dynamic changes of hydrological connectivity, and with the increase of climate change and human activities, the relationship between hydrological connectivity and the water environment is becoming more and more complex, which is ignored in the current research on hydrological processes in the arid zone
.

In order to solve this problem, the research team of Chen Yaning, a researcher from the State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, based on the measured water quality data and hydrometeorological data of Bosten Lake in Xinjiang in the past 30 years, comprehensively used hydrological connectivity index (IIC) and multiple linear regression (MSRM) methods to evaluate the dynamic changes of hydrological connectivity in the Bohu Lake Basin from 1990 to 2019 and its influencing factors, revealing the impact
of hydrological connectivity dynamic changes on water quality.

The results showed that from 1990 to 2019, the hydrological connectivity index (IIC) of the Bosten Lake Basin showed an upward trend but was generally low (between 0-0.
2), and the connectivity was higher in the abundant period and oasis area than in the arid period and high-altitude mountainous area.
IIC was significantly positively correlated with precipitation (PREC) (p< 0.
05), and the water resources of river basins in arid areas were formed in mountainous areas, while precipitation in plain areas was scarce, except for extreme heavy rainfall, which had almost no hydrological significance and was difficult to replenish rivers, resulting in a significant negative correlation between hydrological connectivity and actual evapotranspiration (ETa) (p<0.
05).
Higher hydrological connectivity promotes water quality, and the water chemical concentration is low during the period of high hydrological connectivity, and about 75% of the main pollution indicators (TDS, COD, TN) in Bo Lake occur during the period
of high hydrological connectivity.
The relationship between hydrological connectivity and water environment quality was systematically evaluated, which provided strong support
for the sustainable development of the Bo Lake Basin and the response to climate change.

The results were published in Remote Sensing under the title "Hydrological Connectivity Improves the Water-Related Environment in a Typical Arid Inland River Basin in Xinjiang, China
".
The first author of the paper is Dr.
Liu Chuanxiu of Xinjiang Institute of Biological Land, and the research was supported
by the key project of Xinjiang Natural Science Foundation and the key deployment project of the Chinese Academy of Sciences.

Link to the article:

Figure 1.
(a) Time series, trends and phased changes of interannual IIC changes in the Bosten Lake basin, 1990-2019; (b) Dispersion of the IIC in the Bosten Lake Basin 1990 ~ 2019; (c) 1990-2019 IIC swing based on 30-year averages; (d) The distribution of the interannual IIC index in different years
.

Figure 2.
(a) Box plots for 8 WQOs during high connectivity (green zone) and low connectivity (yellow zone), and (b) Box plots for 8 WQOs from May to October, with spring (red) from May to August, summer (green) from June to August, and autumn (blue)
from September-October.