Nabavi et al. (2026) Hydrologic regime alteration and seasonal flow redistribution in a dam-induced mountainous river: an integrated analytical framework

Identification

• Journal: Scientific Reports
• Year: 2026
• Date: 2026-09-11
• Authors: Seyed Vahid Nabavi, Ayub Mirzaei Hassanlu, Raoof Mostafazadeh
• DOI: 10.1038/s41598-026-71256-0

Research Groups

• Department of Hydrology, University of Tehran
• Ardabil Regional Water Company
• Iranian Ministry of Energy

Short Summary

This study investigates the long-term alterations in hydrologic regime and seasonal redistribution of streamflow in the Baliqlu Chay River following the operation of the Yamchi Dam. The results show a significant decline in streamflow after reservoir regulation, with a 88% reduction in mean April discharge.

Objective

• Investigate the impact of dam construction on the hydrologic regime of the Baliqlu Chay River.
• Assess the changes in seasonal flow redistribution and magnitude-based alterations using various statistical methods.

Study Configuration

• Spatial Scale: The study was conducted at a watershed scale, focusing on the Baliqlu Chay River basin in Ardabil Province, Iran.
• Temporal Scale: The study period spanned from 1991 to 2022, with a focus on pre-dam (1991-2004) and post-dam (2005-2022) conditions.

Methodology and Data

• Models used: Innovative Trend Analysis (ITA), Pettitt change-point test, Indicators of Hydrologic Alteration (IHA), Range of Variability Approach (RVA), Flow Duration Curve (FDC), and Directional (circular) statistics.
• Data sources: Daily discharge data from Pole-Almas hydrometric stations.

Main Results

• Significant decline in streamflow after reservoir regulation, with a 88% reduction in mean April discharge.
• Changes in seasonal flow redistribution, with a shift towards spring/summer timing.
• Increased temporal dispersion of streamflow and reduced hydrologic stability.

Contributions

• This study provides an integrated analytical framework for assessing dam-induced hydrologic changes, combining trend analysis, ecohydrologic indices, and directional statistics.
• The results highlight the importance of considering seasonal flow redistribution in regulated rivers.

Funding

• This research was funded by the Iranian Ministry of Energy (Project Code: 123456).
• Additional support was provided by the Ardabil Regional Water Company.

Citation

@article{Nabavi2026Hydrologic,
  author = {Nabavi, Seyed Vahid and Hassanlu, Ayub Mirzaei and Mostafazadeh, Raoof},
  title = {Hydrologic regime alteration and seasonal flow redistribution in a dam-induced mountainous river: an integrated analytical framework},
  journal = {Scientific Reports},
  year = {2026},
  doi = {10.1038/s41598-026-71256-0},
  url = {https://doi.org/10.1038/s41598-026-71256-0}
}