Gupta et al. (2026) Impact of reservoir storage on propagation from meteorological to hydrological drought

Identification

• Journal: Journal of Hydrology
• Year: 2026
• Date: 2026-07-20
• Authors: Ajay Gupta, Manoj Jain, Rajendra Pandey, David M. Hannah
• DOI: 10.1016/j.jhydrol.2026.136061

Research Groups

• Department of Hydrology, Indian Institute of Technology Roorkee, India
• School of Geography, Earth and Environmental Sciences, University of Birmingham, United Kingdom
• Birmingham Institute of Sustainability and Climate Action, University of Birmingham, United Kingdom

Short Summary

This study quantifies how reservoir storage influences the propagation of drought from meteorological to hydrological stages in the Krishna River Basin, demonstrating that reservoirs act as buffers that delay propagation but facilitate the downstream transmission of severe droughts.

Objective

• To quantify the impact of reservoir storage on the propagation of meteorological, agricultural, reservoir, and streamflow droughts.
• To evaluate the role of upstream-downstream hydrological connectivity (using the Downstreamness concept) in shaping drought progression and recovery.

Study Configuration

• Spatial Scale: 11 major reservoirs within the semi-arid Krishna River Basin, India.
• Temporal Scale: 2000–2019.

Methodology and Data

• Models used:
  • Drought Indices: Standardised Precipitation Evapotranspiration Index (SPEI), Standardised Soil Moisture Index (SSMI), Standardised Reservoir Storage Index (SRSI), and Standardised Streamflow Index (SSI).
  • Analytical Framework: Downstreamness concept for hydrological connectivity; estimation of initiation, peak, and termination lags.
• Data sources: Meteorological, soil moisture, reservoir storage, and streamflow data (implied by the use of SPEI, SSMI, SRSI, and SSI).

Main Results

• Propagation Lags: Meteorological-to-agricultural drought propagates rapidly at short timescales. In contrast, agricultural-to-reservoir and reservoir-to-streamflow droughts exhibit longer delays due to the buffering capacity of reservoir storage.
• Recovery Dynamics: Termination lags are most variable for agricultural-to-reservoir drought and shortest for reservoir-to-streamflow drought, indicating rapid downstream recovery once reservoirs are refilled.
• Connectivity Effects: Mild and moderate upstream reservoir droughts rarely propagate downstream. However, severe upstream droughts consistently transmit downstream, characterized by increased severity, longer duration, and delayed onset.
• Water Retention: Downstreamness dynamics reveal shifting patterns of water retention throughout the drought cycle.

Contributions

• Provides a quantitative framework to understand the buffering role of reservoirs in the drought propagation chain (Meteorological $\rightarrow$ Agricultural $\rightarrow$ Reservoir $\rightarrow$ Streamflow).
• Highlights the critical importance of incorporating reservoir connectivity and severity thresholds into basin-scale water management and drought mitigation strategies.
• Offers a transferable methodology for analyzing multi-stage drought propagation in other semi-arid basins.

Funding

• Not specified in the provided text.

Citation

@article{Gupta2026Impact,
  author = {Gupta, Ajay and Jain, Manoj and Pandey, Rajendra and Hannah, David M.},
  title = {Impact of reservoir storage on propagation from meteorological to hydrological drought},
  journal = {Journal of Hydrology},
  year = {2026},
  doi = {10.1016/j.jhydrol.2026.136061},
  url = {https://doi.org/10.1016/j.jhydrol.2026.136061}
}