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A dynamic calculation model for river ecological flow based on variable intervals

Year: 2026
Type: article
Abstract: Conventional ecological-flow assessments often rely on fixed thresholds or static hydrological indices, limiting their ability to capture hydrological variability, ecological-service demands, and reach-scale water losses. To address these limitations, this study develops a dynamic ecological-flow calculation and adaptive regulation model based on variable ecological-flow intervals, in which ecological flow is represented by lower and upper limits rather than a single fixed value. Hydrological shifts are identified using change-point detection, and variable ecological base-flow and incremental-flow intervals are derived by integrating multiple hydrological methods and ecological-service demands. River seepage and water-surface evaporation are further incorporated to derive the final ecological-flow intervals. A guarantee-level-based adaptive regulation mechanism is developed to adjust ecological-flow allocation under different hydrological conditions. The model was applied to the Shaanxi reach of the Wei River mainstream. The results show that ecological-flow intervals generally increase from upstream to downstream and are higher during the flood season than during the non-flood season. The dominant contributors to ecological-flow requirements differed between upstream and downstream reaches, with environmental-protection demand accounting for 64.6%–78.6% of the upper ecological-flow limits at upstream sections and sediment-transport demand accounting for up to 98.0% downstream. Under moderately dry conditions, lower ecological-flow limits generally achieved high guarantee levels, whereas upper ecological-flow limits associated with ecological-service demands showed greater seasonal variability. Under extremely dry conditions, the reliability of upper ecological-flow limits decreased, particularly in downstream reaches, although adaptive regulation improved the guarantee levels of high-priority ecological-service demands. Compared with conventional fixed-threshold ecological-flow approaches, the proposed model provides a more adaptive representation by integrating hydrological regime shifts, ecological-service demands, and reach-scale water losses, thereby supporting ecological-flow management in regulated and water-scarce river systems.
DOI: 10.1016/j.ecolind.2026.115491
Language: English
Open Access status: gold
Estimated APC paid: $3,650
OpenAlex ID: W7213243492
FWCI:
Cites: 43
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Related to: 10