Effects of Irrigation Discharge on Salinity of a Large Freshwater Lake: A Case Study in Chagan Lake, Northeast China

Abstract

The salinization of freshwater lakes by agricultural activities poses a threat to many lake ecosystems around the world. Quantitative, medium- to long-term studies are needed to understand how some common agricultural practices, such as the discharge of crop irrigation in the vicinities of large lakes, may affect lake salinization. In this study, hydrological, hydrodynamics, water quality and meteorological datasets were used to analyze the long-term spatial-temporal variations of water salinities of a major lake, the Chagan Lake, in Northeast China. An integrated hydrodynamics-salinity model was used to simulate lake water salinity changes taking place at different times and locations, including (i) salt accumulations during a non-frozen period, and (ii) the time when water salinity may reach a significant threshold (1 psu) that jeopardizes a major environmental and economic value of this lake (i.e., the cultivation of local fish species). The results confirmed that Chagan Lake was indeed undergoing salinization in the ten year period between 2008 and 2018. The spatial-temporal patterns of the salinization processes were identified. For instance, (i) the mean salinity of the lake water was found to be 0.55 psu in the summer season of the region and 0.53 psu in the winter, and (ii) between May to October the salinity was up to 0.62 psu in the western region of the lake. The rate of salt accumulation was found to be 97 ton per annum during the non-frozen period. The simulation predicted that by 2024 the lake water will become sub-saline (salinity > 1.07 psu) which is toxic to fish species, if the current practice of irrigation discharge into the lake continues. In the scenario that the amount of irrigation discharges into the lake doubles, the western region of the lake will become sub-saline within one year, and then the whole lake within three years. Overall, this study has produced results that are useful to authorities around the world, for balancing the risks and benefits of developing crop irrigation fields in areas surrounding large freshwater lakes.

Urbanization drives geographically heterogeneous freshwater salinization in the northeastern United States

“…In semi‐xeric regions, increasing salinity in both headwater streams and large rivers driven by concentrating salts in groundwaters due to irrigation appears to be common (Cañedo‐Argüelles et al., 2016; Jolly, 1997; Jolly et al., 2001). Similar trends have been detected in cold dryland climates, such as Central Asia (Ginatullina et al., 2017; Liu et al., 2020). Freshwater Salinization Syndrome and widespread alkalinization also commonly occur in temperate and mesic regions.…”

The Capability of high spatial-temporal remote sensing imagery for monitoring surface morphology of lake ice in Chagan Lake of Northeast China

“…We also discovered the spherical ice ball in the neighbourhood of the southeast coast, and this rare geographic scenic attracted our interest, which has been reported in Finland, Japan, and so on (Case, 1906;Loewe, 1949;Langlois, 1965;Eisen et al, 2003;Kawamura et al, 2009). From Figure 9, the occurrence of ice ball needs to meet the strict requirements of climate conditions together during the frozen process: (1) the air temperature varies up and down the freezing point and can meet the freezing conditions; the temperature cannot be lower than -10 ℃.…”

“…The lake area is characterized by semi-arid and sub-humid continental monsoons with air temperature, precipitation, and evaporation of 5.5 ℃, 430 mm, and 1496 mm (Song et al, 2011;Duan et al, 2007). The salinity ranges from 0.31 to 0.78 ‰ (Liu et al, 2020).…”

“…The bottom of Chagan Lake is relatively flat, the soil is primarily powdery-sandy with the type of white calcium-alkaline, and salinized soil farmlands and grassland pastures are widely distributed in the catchment area. The Chagan Lake is a typical seasonal frozen lake, and the existence of ice cover lasts from November to April each cold season, with the maximum ice thickness ranging from 0.8 to 1.1 meters (Liu et al, 2020;Hao et al, 2021). We conducted two field investigations from December 30 to 31, 2020, and January 2 to 4, 2022.…”

Anion-type modulates the effect of salt stress on saline lake bacteria

“…Besides the characteristics of the drainage area, several further processes including anthropogenic and climate drivers can contribute to the high and often variable salinity levels of lakes. For example, shallow saline lakes are particularly exposed to the effect of precipitation and evaporation induced water level fluctuation with droughts leading to drastic increases in salinity and even periodical complete desiccation (Hammer 1986 ; Waiser and Robarts 2009 ; Schagerl 2016 ; Szabó et al 2020 ), while unrestricted water withdrawals from the watershed (e.g., irrigation) can also cause increases in salinity (Liu et al 2020 ).…”