Wu et al. (2025) Cascading effects of cross-year droughts on flow-sediment dynamics across distinct drought types

Identification

• Journal: Journal of Hydrology
• Year: 2025
• Date: 2025-11-14
• Authors: Jiefeng Wu, Jianyun Zhang, Huaxia Yao, Xinwen Peng, Yuliang Zhou, Mei Chen, Xuemei Li, Jie Wang, Guoqing Wang
• DOI: 10.1016/j.jhydrol.2025.134601

Research Groups

• College of Civil Engineering, Hefei University of Technology, Hefei, China
• Nanjing Hydraulic Research Institute, Nanjing, China
• Department of Biology, Chemistry and Geography, Nipissing University, North Bay, Ontario, Canada
• School of Hydrology and Water Resources, Nanjing University of Information Science and Technology, Nanjing, China
• Water Conservation Promotion Center of the Ministry of Water Resources, Beijing, China
• Hydrology Bureau, Yellow River Conservancy Commission, Zhengzhou, China

Short Summary

This study investigates the cascading effects of cross-year meteorological and hydrological droughts on flow-sediment dynamics in seven Loess Plateau tributaries. It reveals that hydrological droughts induce significantly greater reductions in sediment transport rates and larger post-drought surges compared to meteorological droughts, with afforestation further reducing sediment supply efficiency.

Objective

• To develop a framework for identifying cross-year droughts (duration ≥12 months) using Standardized Precipitation Index (meteorological drought index) and Standardized Streamflow Index (hydrological drought index) at a 12-month scale.
• To characterize the dynamics of sediment transport rate (STR) across pre-drought, drought, and post-drought stages.
• To reveal the cascading effects of drought-type specific influence on flow-sediment dynamics.

Study Configuration

• Spatial Scale: Seven tributaries in the Loess Plateau of China.
• Temporal Scale: Cross-year droughts (duration ≥12 months), analyzed across pre-drought, drought, and post-drought stages, using 12-month scale indices.

Methodology and Data

• Models used: Standardized Precipitation Index (SPI), Standardized Streamflow Index (SSI), and power functions to quantify cross-year drought impacts.
• Data sources: Precipitation data (for SPI), streamflow data (for SSI), and sediment transport rate (STR) data for the selected tributaries. Information on afforestation in the Loess Plateau was also considered.

Main Results

• Cascading lag effects exist between meteorological droughts (MD) and hydrological droughts (HD), leading to differential impacts on flow-sediment dynamics.
• Cross-year HD induced a 52.65 % greater reduction in mean sediment transport rate (STR) compared to MD.
• Post-drought STR surges were 3.72-fold higher than those during drought and 7.66-fold higher than pre-drought.
• Average STR is inversely related to drought duration and severity, a relationship particularly pronounced in cross-year HD.
• After afforestation in the Loess Plateau, STR decreased significantly, with sediment supply efficiency declining by 65.6 % during cross-year HD events and 13.13 % during cross-year MD events.

Contributions

• Provides a deeper understanding of the cascading effects of cross-year droughts, distinguishing between meteorological and hydrological drought types, which was previously lacking in research focused on short-term, single-type droughts.
• Offers a framework for identifying cross-year droughts using SPI and SSI at a 12-month scale.
• Quantifies the distinct impacts of different drought types on sediment transport rate dynamics and the influence of afforestation.
• Supports integrated water–sediment management strategies in the study area and potentially other regions.

Funding

Not specified in the provided text.

Citation

@article{Wu2025Cascading,
  author = {Wu, Jiefeng and Zhang, Jianyun and Yao, Huaxia and Peng, Xinwen and Zhou, Yuliang and Chen, Mei and Li, Xuemei and Wang, Jie and Wang, Guoqing},
  title = {Cascading effects of cross-year droughts on flow-sediment dynamics across distinct drought types},
  journal = {Journal of Hydrology},
  year = {2025},
  doi = {10.1016/j.jhydrol.2025.134601},
  url = {https://doi.org/10.1016/j.jhydrol.2025.134601}
}