Baseflow is a vital water source for environmental and economic growth. To reveal the changes in baseflow in an arid area, Loss Plateau, China, we analyzed the annual, seasonal, and monthly baseflow fluctuations in 1981–1990 and 2006–2010. We discussed the effects of PET (potential evapotranspiration), precipitation, HI (humidity index), and temperature might have on baseflow in the basin. Results showed that the annual baseflow decreased significantly, and seasonal baseflow and baseflow index (BFI) were distributed differently in the four seasons. Baseflow and BFI were stable during the winter, but during May and June, baseflow was unstable while BFI remained stable. During 1981–1990, January and December exhibited a slight variation in baseflow, while January, May, and June exhibited a slight variation in BFI. From 2006 to 2015, baseflow was stable, with limited fluctuations in January, February, March, April, May, November, and December. The correlations between baseflow and PET, precipitation, HI, and temperature were neither statistically significant nor robust. Increases in PET, precipitation, HI, and temperature did not result in a corresponding increase or decrease in baseflow from the annual, seasonal, and monthly time scales.

BRCs (bioretention cells), one of many low-impact development (LID) practices, are increasingly utilized to lessen the amount of runoff while simultaneously improving the runoff quality. Because the goal of BRCs and LID designs, in general, is to mimic or replicate the pre-development hydrology, it is critical to evaluate the hydrologic and ecologic performances of the BRC facility from the perspective of replicating the pre-development hydrology. The metrics developed in this study were intended to represent the hydrologic regime including the runoff volume control metrics, peak flow frequency exceedance curve, and flow duration curve. We also used a hydrological indicator of T_0.5, the fraction of a multi-year period in which the flow exceeds the 0.5-year return period storm to represent the performances regarding downstream ecology. The indicators were compared to their pre-development values to determine how closely they reflected and replicated the pre-development state. A long-term stormwater management model (SWMM) model was developed to examine conditions before and after development and water movement in BRCs. When the BRCs facilities areas are 5% of the entire impervious study area, key findings show that: (1) BRCs have significant runoff volume control performances. (2) The peak flow frequency exceedance curve with BRCs could fully match the pre-development scenario for minor rainfall events compared to the 0.1-year storm. Flow duration curves with BRCs showed that, the frequency, magnitude, and duration of small flows that occurred for more than 90% of the total time closely matched those of pre-development hydrology. (3) T_0.5 with BRCs showed significant improvement compared with the value of the area with no BRCs and was close to the pre-development T_0.5. The findings presented in this study indicated the significant performance of BRCs in improving downstream ecology.

Water yield (WY) is an significant characteristic that reflects ecosystem services. In order to realize high-quality development, it is vital to explore the spatial and temporal (ST) distribution of WY and its driving factors in the Yiluo River Basin (YLRB) to uphold ecological stability and advance long-term sustainable growth. This paper quantifies WY in the YLRB from 2010 to 2020 using the WY model in the InVEST toolkit. Exploring ST characteristics and driving factors at both the raster and sub-watershed levels, results indicate that the overall WY (average water depth) of the YLRB in 2010, 2015, and 2020 was 26.93 × 10⁸ m³ (136.50 mm), 22.86 × 10⁸ m³ (113.38 mm), and 26.81 × 10⁸ m³ (137.61 mm), respectively. The spatial pattern of watershed WY remains consistent across various periods, illustrating spatial variation in the depth of low WY in the central and western regions and high WY depth in the eastern region. At the sub-watershed level, the Luo River (LR) Basin has the highest contribution (69%) to the WY of the entire basin and served as the principal WY region of the YLRB. Conversely, the Yiluo River section, formed after the confluence of the Yi River (YR) and the LR, has the lowest WY contribution (7%) in the entire watershed. Distinct variations exist in the WY capacity among various land use (LU) types. Construction land (CSL) and unused land (UL) exhibited the highest WY capacity (315.16 mm and 241.47 mm), whereas water area (WA) had the lowest (0.01 mm). WY was significantly positively correlated with slope, precipitation, actual evapotranspiration, percentage of cultivated land, and NDVI. It showed a significant negative correlation with altitude, WA, and population density. This study helps promote the research and development of watershed ecosystem services. It also provides scientific support resolving conflicts between watershed protection and economic development and promoting harmony in the YLRB.

Study region: Rainfall forcing followed the design-storm characteristics of Zhengzhou, a rapidly urbanizing city in central China. A generalized urban catchment–bioretention system was used to examine hydrological responses across diverse catchment and facility conditions.Study focus: Conventional runoff-volume and peak-reduction metrics provide limited insight into internal water-pathway allocation and overflow development. We developed a multi-indicator diagnostic framework using 12,000 SWMM event simulations covering four return periods, three rainfall temporal patterns, and 1,000 parameter sets. Nine indicators characterized runoff mitigation, water-pathway allocation, storage response, and overflow dynamics. Factors influencing bioretention performance were grouped into three physically interpretable categories represented by equivalent hydraulic loading Le, equivalent vertical infiltration capacity Ce, and equivalent storage capacity Se. Interpretable machine learning and response-regime analysis identified dominant controls and synthesized multivariate responses.New hydrological insights: Increasing rainfall-driven hydraulic loading shifted water allocation away from infiltration/seepage, underdrain discharge, and end-of-event storage toward surface overflow. Overflow also began earlier and lasted longer. Among the three equivalent parameters, Le showed the strongest and most consistent association with multivariate responses and distinguished regimes ranging from effective internal regulation to overflow-dominated operation. These findings indicate that bioretention performance degradation is better understood as a nonlinear reorganization of water pathways and response states than as a uniform decline in aggregate runoff-control efficiency, providing a transferable process-based interpretation across comparable loading–capacity conditions.