Water conservation (WC) is an essential terrestrial ecosystem service that mitigates surface runoff and replenishes groundwater, which has received considerable attention under the dual pressures of climate change and human activity. However, there is insufficient understanding of the trends in WC changes on temporal (annual, monthly, daily), spatial, and ecosystem scales. This study proposed a quantitative assessment methodology framework (QAMF) for analyzing the spatiotemporal variation of WC under different discontinuous ecosystems. The QAMF mainly used models and methods such as the hydrological model (SWAT), calibration and uncertainty program (SWAT-CUP), WC calculation formula (water balance method), and spatial analysis method (empirical orthogonal function and wavelet analysis). It was applied to the source region of the Yellow River (SRYR), where the ecological landscape pattern underwent varying degrees of degradation, and WC capacity decreased. The results show that: Firstly, the constructed SWAT in the SRYR had high accuracy, and the proposed formula for calculating WC was suitable for multi-temporal scale analysis of WC in spatially distributed discontinuous basins. Secondly, the annual and monthly WC were respectively 81.00-184.13 mm and -28.58-107.64 mm, and daily WC was positive during extreme precipitation periods and negative during dry periods. The regulating effect of WC was fully reflected on the daily scale, partially reflected on the monthly scale, and absent on the annual scale. Third, the crucial WC area was mainly distributed in the southeast, and there was a significant primary yearly cycle of WC in the SRYR. Finally, different ecosystems exhibited different WC capabilities, and protecting the diversity of ecosystems played an essential role in maintaining and improving the WC function in the SRYR. This project has great scientific significance and technological support for scientifically evaluating the WC capacity in the SRYR.

Mastering the spatiotemporal variations and driving factors of runoff and sediment load (RS) in the Yellow River Basin (YRB) from the perspective of scientific governance is essential for formulating management strategies. Based on the clustering analysis, Pettitt abrupt change test, Mann-Kendall trend test, Sen's slope estimator, Wavelet analysis, and Double Mass Curve (DMC), This study analyzed the RS series from 32 mainstem and 34 major tributary hydrological stations across the YRB from 1960 to 2023, identified key driving factors, and quantified their attribution rates. The main findings were as follows: (1) The YRB was categorized into five segments (B1: upstream of Jimai, B2: Jimai-Tangnaihai, B3: Tangnaihai-Dengkou, B4: Dengkou-Longmen, B5: Longmen-Lijin) and three periods (P1: 1960-1986, P2: 1987-1999, P3: 2000-2023), with significant differences in RS distribution, particularly larger runoff in the upstream of Lanzhou and larger sediment load in the Toudaoguai-Tongguan. (2) Significant decreasing trends in RS were observed across the basin, particularly in the runoff of the B4-B5 and sediment load in B3-B5, with reductions in runoff modulus/sediment load modulus by 62.34%/33.42% and 67.20%/60.79% in the P2 and P3 compared to P1, respectively. (3) The contribution of human activities to the reduction of RS was found to be substantial, accounting for 87.77% of the runoff decrease and 84.16% of the sediment load reduction, while climate change accounted for a relatively minor portion (12.23% and 15.84%, respectively). The research results can provide scientific and technological support for the rational utilization of water resources and ecological protection in the basin.

The watershed system has a complex game relationship between the benign operation and coordinated development of various elements of flood-sediment transportation, eco-environment, and socio-economy (FES). With the increasing breadth, depth, and intensity of human activities in watersheds, it is urgent to coordinate the FES. The relationship of water–sediment in the Yellow River Basin (YRB) is complex, with a prominent contradiction in water supply and a fragile ecosystem. This research tries to build a comprehensive evaluation model for FES and explore the complex interaction between FES in the YRB from 2000 to 2020. The results demonstrated that (1) the comprehensive flood-sediment transportation index (CFTI) and comprehensive eco-environment index (CEI) presented fluctuating growth. In contrast, the comprehensive socio-economy index (CSI) revealed a linear growth trend. The CFTI of Sanmenxia, CEI of Toudaokuan, and CSI of Ningxia had the highest growth rates, with 36.03%, 6.48%, and 107.5%, respectively. (2) FES's positive and negative effects were alternating, with heterogeneity in both time and space. (3) The coupling coordination degree (CCD) in the YRB indicated an increasing trend, ranging from 0.53 to 0.87, from reluctantly coordinated development to good coordinated development. The lagging subsystem was CFTI (2000–2001 and 2008–2020) and CSI (2002–2007), and the CEI was not lagging. (4) Exploratory Spatial Data Analysis (ESDA) demonstrated significant differences in the CCD of the YRB, and areas with similar CCD within the basin tend to be centrally distributed in space. At the same time, there was negative spatial autocorrelation in coordination. The results provide a scientific theoretical and methodological framework for strategic research on the YRB system's governance, protection, and management.