River-lake systems, crucial to both the ecological environment and societal development, have been affected by increasing anthropogenic activities in addition to climate and environmental changes. Here, annual water discharge and sediment load data (1956–2017) and rainfall data (1960–2016) from Dongting Lake in the middle catchment of the Yangtze River were analysed at four major inlets and one outlet, and their connections with lake level variations were evaluated using multiple analytical methods. The results show that minor fluctuations were found in rainfall and discharge during the study period, but the sediment load entering Dongting Lake decreased significantly from 231 mt/year (before 1969) to 123 mt/year (1970–2002) and then 17 mt/year (after 2003, post TGD). The variation in the sediment was mainly induced by increasing anthropogenic activities in the lake system. During period 1 (before 1969), human impact was weak compared to the dominant natural forces. However, anthropogenic force showed an increasing contribution to the loss of sediment load since then, as it increased from 43.0% (1970–1987, post cut-off engineering) to 64.8% (1988–2002, post Gezhou Dam) and extended to 90.2% during 2003–2017 (post TGD). Nevertheless, continuous sediment accumulation over the past decades in the lake has caused a rising water level. During period 1, high sediment input contributed to an average annual increase of 13.96 cm in the lake level, but it decreased significantly to 1.94 cm year⁻¹ during 1970–2002 due to intensive anthropogenic regulations. Since 2003, the completion of the TGD intercepted abundant sediment, eventually leading to a shift from net deposition to net loss of the sediment budget in Dongting Lake, and consequently, the lake level fell. In the future, if the net sediment supply was kept below ~18 mt/year, the lake level would continue to fall, causing severe problems to the lake ecosystem, especially during drought years.

河湖系统对生态环境和社会发展都至关重要，除气候和环境变化外，还受到越来越多的人为活动的影响。在此，分析了长江中游洞庭湖4个主要入口和1个出口的年流量和泥沙负荷数据（1956-2017）和降雨数据（1960-2016）及其与湖水位变化的联系。使用多种分析方法进行评估。结果表明，研究期间降雨量和流量略有波动，但进入洞庭湖的泥沙负荷从231 mt/年（1969年之前）显着下降到123 mt/年（1970-2002年），然后是17 mt/年。年（2003 年之后，TGD 之后）。沉积物的变化主要是由湖泊系统中增加的人类活动引起的。在第一阶段（1969 年之前），与占主导地位的自然力量相比，人类的影响是微弱的。然而，自那时以来，人为力量对泥沙负荷损失的贡献越来越大，从43.0%（1970-1987，截流工程后）增加到64.8%（1988-2002，葛洲大坝后）并扩展到90.2 2003-2017 年期间的百分比（TGD 后）。然而，过去几十年在湖中不断积累的沉积物导致水位上升。第一期，高泥沙输入导致湖面水位年均增加13.96厘米，但显着下降至1.94厘米年 从那时起，人为力量对泥沙负荷损失的贡献越来越大，从 43.0%（1970-1987，截流工程后）增加到 64.8%（1988-2002，葛洲大坝后），并扩大到 90.2% 2003-2017 年（TGD 后）。然而，过去几十年在湖中不断积累的沉积物导致水位上升。第一期，高泥沙输入导致湖面水位年均增加13.96厘米，但显着下降至1.94厘米年 从那时起，人为力量对泥沙负荷损失的贡献越来越大，从 43.0%（1970-1987，截流工程后）增加到 64.8%（1988-2002，葛洲大坝后），并扩大到 90.2% 2003-2017 年（TGD 后）。然而，过去几十年在湖中不断积累的沉积物导致水位上升。第一期，高泥沙输入导致湖面水位年均增加13.96厘米，但显着下降至1.94厘米年 过去几十年在湖中不断积累的沉积物导致水位上升。第一时期，高泥沙输入导致湖面水位年均增加13.96厘米，但显着下降至1.94厘米年 过去几十年在湖中不断积累的沉积物导致水位上升。第一期，高泥沙输入导致湖面水位年均增加13.96厘米，但显着下降至1.94厘米年^-1在 1970-2002 年期间由于密集的人为规定。2003年以来，三峡大坝的建成截留了丰富的泥沙，最终导致洞庭湖泥沙收支由净沉降转为净损失，湖水位随之下降。未来，如果净沉积物供应量保持在~18 mt/年以下，湖泊水位将继续下降，对湖泊生态系统造成严重问题，特别是在干旱年份。