Quantitative assessment of sediment sources in the Shanxi Fenhe River reservoir section: A comparative study using end-member mixing analysis and sediment fingerprinting

Sediment accumulation in the upper Fenhe River basin threatens reservoir storage and ecological security, exemplifying broader soil erosion challenges on the Loess Plateau. To address the difficulty of tracing sources under highly homogeneous geochemical conditions, this study integrates End-Member Mixing Analysis (EMMA) with sediment fingerprinting (SF) into a combined framework for sediment source apportionment. Results indicate that: sediments are primarily sourced from proximal tributaries, with Jianhe, Lanhe, Dongnian, and Xinian Rivers contributing 91.6%; the SF approach provides higher precision in identifying weak signals and minor sources (<1%) with superior robustness, whereas EMMA offers efficiency in rapidly attributing sediments to dominant sources, highlighting the complementary strengths of the two approaches; sediment generation is driven by the coupling of loess parent material and anthropogenic disturbance, with mining as a key amplification factor and sloping farmland having limited impact. A zoned management framework targeting the main sediment-contributing tributaries-“Source Interception-Process Regulation-Terminal Stabilization”-effectively strengthens full-chain management of fine sediment. This study identifies critical sediment-producing areas and controlling factors, establishes management priorities, and provides a scientific basis for shifting sediment control in the upper Fenhe from broad remediation to precise regulation, offering practical guidance for ecologically fragile regions of the Loess Plateau.