Shoaib et al. (2025) Hydro-geospatial Modeling for Assessing the Effectiveness of Flood Dikes against Unprecedented Floods: A Case Study of the Chenab River Floodplain in Pakistan

Identification

• Journal: Earth Systems and Environment
• Year: 2025
• Date: 2025-10-17
• Authors: Muhammad Shoaib, Saqib Ashraf, Noor Muhammad Khan, Muhammad Riaz
• DOI: 10.1007/s41748-025-00884-9

Research Groups

• Punjab Irrigation Department, Government of Punjab, Lahore, Pakistan
• Civil Engineering Department, University of Engineering and Technology (UET), Lahore, Pakistan
• Water Engineering and Management (WEM), School of Engineering and Technology (SET), Asian Institute of Technology (AIT), Klong Luang, Pathum Thani, Thailand
• Sanyu Consultants, Tokyo, Japan

Short Summary

This study developed and validated a hydro-geospatial model to assess flood extents, inundation depths, and the effectiveness of flood dikes in the Chenab River floodplain, Pakistan, against unprecedented floods of various return periods, identifying vulnerable infrastructure and recommending specific improvements.

Objective

• To characterize the hydrological regime by analyzing historical flow data for trends, variability, and extreme events.
• To simulate flood flows and predict water surface elevations and flow velocities using HEC-RAS.
• To conduct flood inundation mapping using GIS techniques to delineate flood-prone areas and estimate inundation depths and extents for various return periods.
• To assess the effectiveness of existing flood control infrastructure (e.g., embankments) in mitigating flood risks.
• To identify vulnerable areas susceptible to flooding, including critical infrastructure, settlements, and agricultural lands.
• To propose effective flood risk mitigation strategies, such as raising the top level of levees.

Study Configuration

• Spatial Scale: A 209 km reach of the Chenab River floodplain, from Qadirabad Barrage to Trimmu Barrage, in Punjab Province, Pakistan. The basin area up to Qadirabad Barrage is 32,685 km².
• Temporal Scale: Historical annual flood peak data from 1983 to 2015. Calibration and validation performed using daily flow and stage data from the 2006 and 2014 flood events. Flood scenarios modeled for 25, 50, 100, and 200-year return periods.

Methodology and Data

• Models used:
  • HEC-RAS (Hydrologic Engineering Center’s River Analysis System) for hydrodynamic modeling and water surface profile simulation.
  • HEC-GeoRAS for GIS integration and data preparation for HEC-RAS.
  • Gumbel’s Extreme Value Distribution for flood frequency analysis.
  • ArcGIS for flood inundation mapping, spatial analysis, and visualization.
• Data sources:
  • SRTM DEM (Digital Elevation Model) with 30 m resolution for river and floodplain geometry extraction.
  • Physical surveys for river cross-sections and floodplain elevations.
  • Historical annual flood peak data (1983–2015) for the Chenab River.
  • Daily flow and stage data for the 2006 and 2014 flood events.
  • Rating curves for Qadirabad and Trimmu barrages.
  • High-resolution satellite imagery (Google Earth) and base maps in ArcGIS for detailed land use information (river creeks, barrages, roads, canals, cropped areas, dunes, flood bunds, spurs).
  • Flood fighting reports, annual headworks reports, and annual flood reports.
  • Pre-flood inspection reports for flood infrastructure condition assessment.
  • Manning’s roughness coefficients based on literature and site-specific observations.

Main Results

• The hydrodynamic model was successfully calibrated (R² = 0.944 and 0.933; Nash-Sutcliffe Coefficient (NSC) = 0.850 and 0.877) and validated (R² = 0.989 and 0.967) at Chiniot and Rivaz gauging stations, demonstrating high accuracy.
• Flood discharges for various return periods at Qadirabad were determined: 25-year (27,931.65 m³/s), 50-year (34,098.65 m³/s), 100-year (38,000.00 m³/s), and 200-year (41,623.98 m³/s).
• The 2014 flood was found to have return periods of 24 years at Qadirabad and 6 years at Trimmu.
• Maximum flood depths in the floodplain for different return periods were: 11.73 m (25-year), 12.58 m (50-year), 13.46 m (100-year), and 14.46 m (200-year).
• The existing flood control infrastructure (FCI) was effective for 25, 50, and 100-year return period floods, but proved ineffective for the 200-year return period flood, especially where average flood depths exceeded 6 m.
• Specific flood bunds (Thatta Mahla, Jhang, and Massan Disty) were identified as unsafe against 100- to 200-year return period floods, with overtopping depths of 2.77 m, 1.4 m, and 2.94 m, respectively.
• The celerity of the 2014 flood wave was calculated to be 0.361 m/s (1.3 km/h).

Contributions

• Developed and validated a robust hydro-geospatial modeling framework for flood risk assessment and infrastructure effectiveness evaluation in the Chenab River floodplain, filling a critical gap in GIS-based flood hazard mapping for the region.
• Provided a quantitative assessment of the overall and individual effectiveness of existing flood control infrastructure against unprecedented flood events (up to 200-year return periods).
• Identified specific vulnerable flood dikes and provided actionable recommendations for structural interventions, including precise raising heights (3.77 m for Thatta Mahla, 2.4 m for Jhang, and 3.94 m for Massan Disty flood bunds) to enhance resilience against extreme floods.
• Generated comprehensive flood extent, depth, and hazard maps for various return periods, offering valuable insights for planners and policymakers to inform flood mitigation strategies and contribute to sustainable development goals (SDG 6 and 13).

Funding

None explicitly stated for research execution, but data provision was acknowledged from the Punjab Irrigation Department (PID) and Federal Flood Commission (FFC).

Citation

@article{Shoaib2025Hydrogeospatial,
  author = {Shoaib, Muhammad and Ashraf, Saqib and Khan, Noor Muhammad and Riaz, Muhammad},
  title = {Hydro-geospatial Modeling for Assessing the Effectiveness of Flood Dikes against Unprecedented Floods: A Case Study of the Chenab River Floodplain in Pakistan},
  journal = {Earth Systems and Environment},
  year = {2025},
  doi = {10.1007/s41748-025-00884-9},
  url = {https://doi.org/10.1007/s41748-025-00884-9}
}