[1]Bi Jieyu,Li Ruixian,Zhang Shouhong,et al.Evaluation and simulation of roof rainwater runoff quality in Beijing based on explainable machine learning[J].Research of Soil and Water Conservation,2025,32(06):280-289.[doi:10.13869/j.cnki.rswc.2025.06.020]
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Research of Soil and Water Conservation[ISSN 1005-3409/CN 61-1272/P] Volume:
32
Number of periods:
2025 06
Page number:
280-289
Column:
Public date:
2025-10-20
- Title:
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Evaluation and simulation of roof rainwater runoff quality in Beijing based on explainable machine learning
- Author(s):
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Bi Jieyu1,Li Ruixian1,Zhang Shouhong1,2,3,Zhang Fan1,Zhang Sunxun4,Wei Zhen5
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(1.School of Soil and Water Conservation,Beijing Forestry University,Beijing 100083,China;2.JixianNational Forest Ecosystem Observation and Research Station,Linfen,Shanxi 042200,China;3.Beijing Engineering Research Center of Soil and Water Conservation,Beijing 100083,China;4.State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin,China Institute of Water Resources and Hydropower Research,Beijing 100048,China;5.Beijing Songshan National Nature Reserve...)
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- Keywords:
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rainwater harvesting system; runoff quality; machine learning; SHAP model
- CLC:
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TU991.34
- DOI:
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10.13869/j.cnki.rswc.2025.06.020
- Abstract:
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[Objective] This study aims to quantitatively evaluate the runoff quality characteristics of roof rainwater harvesting system under differentiated meteorological and environmental factors in Beijing, and to analyze their primary influencing factors, to provide a scientific basis for the design of urban roof rainwater harvesting systems and comprehensive evaluation of runoff quality. [Methods] From July to November 2023, experimental rainwater harvesting system was installed at five sites across different districts of Beijing to monitor environmental factors, rainfall characteristics, and runoff quality data. The Runoff Quality Index(RQI) was used for runoff quality evaluation, and an explainable random forest regression model was established to predict RQI based on meteorological and environmental factors. [Results] (1) Pollutant concentrations in runoff exhibited distinct distribution patterns across regions. Haidian and Yanqing districts showed higher RQI values, while Fangshan had the lowest.(2) The random forest model achieved relatively accurate prediction of RQI values, demonstrating high precision(R2 =0.853 for calibration, R2 =0.745 for validation).(3) SHAP model analysis indicated that rainfall had the greatest influence on RQI, with a critical threshold of approximately 8 mm for the first-flush effect. [Conclusion] Significant differences in roof runoff quality were observed across different districts of Beijing, primarily driven by rainfall, antecedent dry period, and atmospheric NO2 concentration. The random forest model effectively predicted runoff quality, and its integration with the SHAP model enabled quantitative assessment of the contribution of each influencing factor.