Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, PR China.
Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, PR China; University of Chinese Academy of Science, 19 Yuquan Road, Beijing 100049, PR China.
Sci Total Environ. 2019 Apr 10;660:245-259. doi: 10.1016/j.scitotenv.2019.01.015. Epub 2019 Jan 5.
Small, seasonal lakes that exist in floodplains are rarely investigated, and yet they play an important role in the protection of biodiversity and are highly susceptible to modification due to human activities. This study presents a first attempt to combine hydrodynamic modeling and statistical methods to investigate hydrological connectivity and its relationship with the water quality of nine seasonal lakes within the floodplains of Poyang Lake (China). The hydrodynamic model reproduced reasonably well the hydrological regime of the lake and surrounding floodplains, based on field measurements and remote sensing data. Floodplain lakes exhibit similar water-level dynamics to the main lake during connected periods of flooding, while they decouple from the main lake during recession periods. Geostatistical results reveal that although the north-south hydrological connectivity extends over a longer pathway than the west-east connectivity, the rapid reduction in the west-east connectivity indicates a more sensitive response. The west-east connectivity tends to play a dominant role in affecting the interactions between the main lake and floodplains, as expected. Statistical methods indicate that surface hydrological connectivity across the floodplain results in an enhanced spatial similarity in the water quality of the floodplain lakes, in terms of a multitude of water quality parameters (TN, TP, NH-N, NO-N, NO-N, PO, COD, and Chl a), while surface hydrological isolation was observed to increase the water quality differences between the seasonal lakes. Additionally, enhanced hydrological connectivity may lead to improved water quality of the seasonal lakes from low connectivity to high connectivity condition. Hydrological connectivity may be a key factor controlling the dynamics in water quality between seasonal lakes. The findings of this study support the management of both Poyang Lake and the floodplain wetlands by providing important information on both water resource and water quality, and proposals to better manage the impacts of intensive human activities.
小型季节性湖泊存在于洪泛区，很少被研究，但它们在保护生物多样性方面发挥着重要作用，并且由于人类活动的影响，它们非常容易发生变化。本研究首次尝试结合水动力模型和统计方法来调查洪泛区九个季节性湖泊的水文学连通性及其与水质的关系。该水动力模型基于现场测量和遥感数据，合理地再现了湖泊和周围洪泛区的水文学状况。在连接洪水期，洪泛区湖泊的水位动态与主湖相似，而在退水期则与主湖分离。地统计学结果表明，尽管南北向的水文学连通性比东西向的更长，但东西向的连通性迅速减少表明其对水流变化更为敏感。预计，尽管南北向的水文学连通性比东西向的更长，但东西向的连通性迅速减少表明其对水流变化更为敏感。东西向的连通性往往在影响主湖和洪泛区之间的相互作用方面发挥主导作用。统计方法表明，跨越洪泛区的地表水文连通性导致洪泛区湖泊水质的空间相似性增强，就多种水质参数（TN、TP、NH-N、NO-N、NO-N、PO、COD 和 Chl a）而言，而地表水文隔离则观察到季节性湖泊之间的水质差异增大。此外，增强的水文连通性可能会导致季节性湖泊的水质从低连通性到高连通性条件下得到改善。水文连通性可能是控制季节性湖泊水质动态的关键因素。本研究的结果支持对鄱阳湖和洪泛湿地的管理，为水资源和水质提供了重要信息，并提出了更好地管理人类活动密集影响的建议。
