Raw data of the study.

The dynamics of physicochemical properties within rivers are essential for understanding the health and functioning of aquatic ecosystems. This study investigated the spatial and seasonal variability of water quality in both water and sediment phases across rivers with different pollution sources in the Jinjing Basin: Tuojia River (TR), Tuojia River substream (TRS) (farmland), Guojia River (GR), Guojia River substream (GRS) (woodlands) and Jinjing River (JR) (residential). Samples were collected during wet and dry seasons and analyzed using multivariate statistical approaches. Farmland-dominated rivers (TR and TRS) exhibited the highest nutrient concentrations in both water and sediment phases, with elevated nutrients, soil organic matter (SOM), and dissolved organic carbon (DOC), driven by fertilizer runoff and organic inputs. In contrast, woodland rivers (GR and GRS) displayed the lowest nutrient levels, benefiting from dense vegetation and natural nutrient retention processes. Seasonal variability revealed higher nutrient concentrations in the water phase and increased levels of ammonium nitrogen (NH4+-N) and SOM in the sediment phase during the wet season. In the dry season, reduced flow enhanced photosynthesis, resulting in higher pH and dissolved oxygen levels in the water phase and elevated pH and DOC in sediment. Principal component analysis further confirmed that nutrient pollution is predominantly influenced by agricultural runoff during the wet season, while reduced runoff in the dry season allowed natural processes to dominate. The findings underscore the importance of managing nutrient loads in both water and sediment, especially in farmland areas to ensure the sustainability of water resource management in the Jinjing Basin.

河流内理化属性的动态变化，是理解水生生态系统健康状态与运行机制的核心依据。本研究针对金井流域内不同污染源类型的河流，开展了水体与沉积物两相水质的空间及季节变异特征调查，涉及的河流包括：拓家河（TR）、拓家河支流（TRS，农田流域）、郭家河（GR）、郭家河支流（GRS，林地流域）以及金井河（JR，居民区流域）。研究于丰水期与枯水期分别采集样品，并采用多变量统计方法开展分析。以农田为主要污染源的河流（TR与TRS）在水体与沉积物两相中均表现出最高的营养盐浓度，其营养盐、土壤有机质（soil organic matter, SOM）与溶解性有机碳（dissolved organic carbon, DOC）水平均显著升高，该现象由化肥径流与有机输入所驱动。与之相反，以林地为主的河流（GR与GRS）营养盐水平最低，这得益于其茂密的植被覆盖与天然的营养盐滞留过程。季节变异特征显示，丰水期水体相营养盐浓度更高，沉积物相中的铵态氮（ammonium nitrogen, NH₄+-N）与土壤有机质水平亦有所提升。枯水期时，径流量减少会强化光合作用，使得水体相的pH值与溶解氧水平升高，沉积物相的pH值与溶解性有机碳含量亦随之上升。主成分分析进一步证实：丰水期的营养盐污染主要受农业径流影响，而枯水期径流量减少则使得天然过程成为主导因素。本研究结果强调，需同时管控水体与沉积物中的营养盐负荷，尤其在农田流域，以此保障金井流域水资源管理的可持续性。