Assessment of hydrologic alteration induced by the Three Gorges Dam in Dongting Lake, China

Abstract

Water-level variations are an internal aspect of lake ecosystems that play a key role in structuring aquatic diversity and providing ecosystem services. In this study, the hydrologic alteration of Dongting Lake induced by the Three Gorges Dam (TGD) was assessed using indicators of hydrologic alteration and range of variability approach. The results demonstrate a declining trend in autumn water level (0.52-2.26 m) and 5-35 days' advancement for date of minimum annual water level because of the impound of water by the TGD in early autumn. The spatial patterns in the degree of the indicators of hydrologic alteration were different among the sub-lake regions. Annual minimum water level and timing of annual extreme water level suffered a high degree of alteration in the eastern part of the lake, whereas autumn water level, date of minimum water level, and number of reversals in the western part of the lake showed a high degree of alteration. The average integrated degree of hydrologic alteration (D 0 ) for Dongting Lake was 50.40%, indicating that the hydrologic regime suffered a moderate alteration. The most ecologically relevant hydrologic indicators are critical for understanding eco-hydrology. On the basis of principal component analysis, the five selected ecologically relevant hydrologic indicators were 90-day minimum, date of minimum, high pulse duration, date of maximum, and May water level. Further studies are required to understand the impact of the TGD on water conditions in Dongting Lake, especially related to the response of the aquatic ecosystem.

Spatial and Temporal Evolution Characteristics of Low Water Level Based on 70 years’ Measured Data: A Case Study of Dongting Lake in China

“…It shows that the water level in January and the lowest water level in 1, 3, 7, and 30 days at the mouth of Dongting Lake have changed significantly, and the degree of hydrological change was greater than 85%, which was mainly affected by the increase in rainfall and dam regulation (Cheng et al, 2019). Similar conclusions also appear in the research studies of Liang et al (2018), Dai et al (2018), and Cheng et al (2018). The water storage of TGR exposed the wetland earlier and prolonged the autumn drought by about 30%.…”

Statistical Assessments of River Flow Alterations and Environmental Flow Standards

“…Many researchers have employed IHA methods to investigate alterations to flows in river systems in various countries (Gao et al 2009;Lin et al 2014;Peres and Cancelliere 2016;Cheng et al 2018;Pal et al 2019). Yang (2016) applied the IHA in research studies of the Brazos and Trinity River basins of Texas.…”

Impact of river flow modification on wetland hydrological and morphological characters

“…There are many methods of measuring flow alteration like the Range of variability approach (Richter et al, 1998;Yang et al, 2008;Cheng et al, 2018;Ali et al, 2019;, Revised range of variability approach (Ge et al, 2018), Histogram comparison approach (Huang et al, 2017), Histogram matching approach (Shiau and Wu, 2008;Huang et al, 2016). Among this range of variability approach adopted to measure the flow alteration of the Atreyee river.…”