Water Level Fluctuation under the Impact of Lake Regulation and Ecological Implication in Huayang Lakes, China

Abstract

Water level fluctuation (WLF) in shallow lakes in the middle and lower reaches of the Yangtze River has been a concern of many researchers. This work aims to investigate the effects of climate change and regulation of floodgates and the Three Gorges Dam (TGD) on WLF and lake volume in Huayang Lakes during the past 52 years. The results revealed that precipitation is the dominant factor that leads to seasonal variation of lake levels, whereas regulation of floodgates and TGD are the key drivers of hydrology regime change in the past 20 years. Natural lake regime has higher water level when there is more precipitation and less lake volume. Floodgates and TGD regulations have changed this pattern since 2003, causing less difference in water level in spite of more precipitation and lake recession. Under the combined impacts of floodgates and TGD regulations, Huayang Lakes have experienced a prolonged outflow time since 2003 and the contribution rate caused by the floodgates and TGD regulations has increased by 19.90%. Additionally, the water level of Huayang Lakes decreased by approximately 0.3~0.5 m from September to November, but it showed no alteration from January to March in the past two decades. This indicated that floodgate regulations used for agricultural irrigation and fishery culture dominate the hydrology regime in winter and early spring. This study is beneficial for aquatic ecosystem protection in floodgate-controlled lakes under the circumstance of climate change and vigorous anthropology activities.

The effects of ENSO, climate change and human activities on the water level of Lake Toba, Indonesia: a critical literature review

“…Awange et al (2008b) stated that the leading cause is the increase in the Owen Falls Dam volume. This finding was confirmed by the studies carried out by Bashirian et al (2020) and Fan et al (2020), who stated that regulations of the dam have indirectly created a significant decrease in the lake level. The surface elevation of Lake Mead has also decreased by 40 m since 1999 in accordance with prolonged drought and an increase in water supply demand due to population growth (Holdren and Turner, 2010;Siyal et al 2019).…”

“…However, no prior studies have been devoted to investigating their effects on lake level declines and fluctuations. Studies carried out by Bashirian (2020), Fan (2020), and Sinyukovich and Chernyshov (2019) focused on human activities associated with dam regulation and their use for agricultural irrigation and hydropower generation. Dehghanipour et al (2019Dehghanipour et al ( , 2020a developed a model to determine the potential water management strategies sourced from lakes for agricultural land irrigation including Lake Urmia in Iran.…”

Satellite Imageries and Field Data of Macrophytes Reveal a Regime Shift of a Tropical Lake (Lake Ziway, Ethiopia)

“…A similar scenario was observed in Lake Naivasha after the introduction of floriculture [60]. According to [85,95] a change from a smooth and gradual to a drastic regime shift may result from large external factors such as water abstraction and flood gate regulation. Thus, the abrupt change in mean water level observed at Lake Ziway in 2003 could be a result of the extreme drought that occurred in the region and of an extensive water abstraction and river diversion.…”

“…As the water level drops, changes occur in the distribution and diversity of shoreline macrophytes. If a decline in the water level of a lake is continuous with slow recovery and refill time, native macrophytes may be replaced by invasive aquatic and semi terrestrial species [36,85,97]. Our study showed a decline in the surface water area and in macrophyte distribution.…”

“…Long term water level fluctuations are due mainly to climatic conditions or a sustained anthropogenic disturbance [60,84,85]. In our study, the long-term water level of Lake Ziway showed a decreasing trend, similar to that of neighboring Ethiopian rift lakes, in the past three decades [86][87][88].…”