Mutar et al. (2026) Assessment of Haditha Dam’s Operation Under Historical Hydrological Conditions: Comparison Between Actual and Simplified Operation Using the HEC-HMS Model in Different Scenarios

Identification

• Journal: Hydrology
• Year: 2026
• Date: 2026-03-11
• Authors: Ghasaq Saadoon Mutar, Hidayah Bte Basri, Mahmoud Saleh Al-Khafaji
• DOI: 10.3390/hydrology13030091

Research Groups

• Department of Civil Engineering, College of Engineering, Universiti Tenaga Nasional, Malaysia
• Institute of Energy Infrastructure (IEI), College of Engineering, Universiti Tenaga Nasional, Malaysia
• Department of Water Resources Engineering, College of Engineering, University of Baghdad, Iraq

Short Summary

This study evaluated the HEC-HMS model's applicability for simulating inflow hydrographs and supporting reservoir operation at Haditha Reservoir, Iraq, under historical hydrological conditions. It found that a rule-based operation scenario significantly improved reservoir storage and water levels during dry periods compared to existing and hydraulic-based operational policies.

Objective

• To evaluate the applicability of the HEC-HMS model for simulating inflow hydrographs and supporting reservoir operation in data-scarce arid environments, focusing on Haditha Reservoir.
• To compare the actual Haditha Dam operation with three simulated scenarios (outflow curve routing, outflow structure routing, and rule-based operation) under long-term historical hydrological conditions (2004–2024).

Study Configuration

• Spatial Scale: Haditha Dam and Reservoir on the Euphrates River in Anbar Province, western Iraq. The dam has a length of approximately 8.94 km, a maximum height of 57 m, and a crest level of 154 m. The reservoir has a total capacity of about 9.25 billion cubic metres and an area of about 500 square kilometres. The catchment area upstream of the dam was delineated using a Digital Elevation Model (DEM).
• Temporal Scale: 20 years of historical hydrological and meteorological data (2004–2024). The model was calibrated for the period 2004–2016 and validated for 2017–2024.

Methodology and Data

• Models used:
  • HEC-HMS (version 4.13) for rainfall-runoff simulation and reservoir operation.
  • Soil Conservation Service Curve Number (SCS-CN) method for rainfall losses.
  • SCS Unit Hydrograph (SCS-UH) method for direct runoff transformation.
  • Lag routing method for channel routing.
• Data sources:
  • Iraqi Ministry of Water Resources (MOWR): Dam structural design data, daily hydrological records (inflow, outflow, reservoir water level, storage, evaporation losses) for 2004–2024.
  • Iraqi Meteorological Organization and Seismology (IMOS): Daily rainfall, air temperature, and evaporation records for 2004–2024 from three meteorological stations (Al-Qaim, Anah, and Rawa).
  • United States Geological Survey (USGS): Digital Elevation Model (DEM) with a 30 m spatial resolution.
  • General Authority of Dams and Reservoirs (GADR), Ministry of Water Resources: Structural and operational information related to the dam.
  • ArcMap (version 10.8) for GIS-based catchment delineation and processing.
  • Estimated average monthly water demand values adopted from Al-Janabi (2004).

Main Results

• The HEC-HMS rainfall-runoff model demonstrated satisfactory performance in simulating inflow hydrographs: Nash–Sutcliffe Efficiency (NSE) of 0.98 and Root Mean Square Error (RMSE) of 29.05 cubic metres per second (m³/s) during calibration (2004–2016), and NSE of 0.97 and RMSE of 28.68 m³/s during validation (2017–2024).
• The rule-based operation scenario showed superior performance in reservoir regulation compared to the observed operation and other hydraulic-based scenarios.
• Under the rule-based scenario, the minimum reservoir elevation increased from 115.8 metres (observed) to 130 metres, and minimum storage increased from 0.47 billion cubic metres (BCM) (observed) to 2.50 BCM, indicating enhanced resilience against low-storage conditions.
• The water deficit was reduced under the rule-based operation compared to the existing operational policy.
• The maximum outflow (1358 m³/s) and maximum reservoir elevation (140 m) under the rule-based operation remained within safe operational limits and below historical maximums (2073 m³/s and 147 m, respectively), without increasing downstream flood peaks.
• Outflow curve and outflow structure scenarios offered marginal improvements but were constrained by their passive hydraulic release mechanisms.

Contributions

• Provided a systematic evaluation of Haditha Dam's operation by directly comparing its actual performance with various simplified and rule-based operational scenarios under long-term historical hydrological conditions (20 years) in an arid/semi-arid environment.
• Demonstrated the reliable application of the HEC-HMS model as a decision-support tool for evaluating reservoir operation in data-scarce arid and semi-arid regions, extending its utility beyond simple flow simulation to comprehensive operational analysis.
• Developed and assessed a rule-based operational strategy that significantly improved reservoir storage and water level maintenance during dry periods, offering a practical framework for enhancing water security and operational efficiency in challenging hydrological conditions.

Funding

This research received no external funding.

Citation

@article{Mutar2026Assessment,
  author = {Mutar, Ghasaq Saadoon and Sidek, Lariyah Mohd and Basri, Hidayah Bte and Al-Khafaji, Mahmoud Saleh},
  title = {Assessment of Haditha Dam’s Operation Under Historical Hydrological Conditions: Comparison Between Actual and Simplified Operation Using the HEC-HMS Model in Different Scenarios},
  journal = {Hydrology},
  year = {2026},
  doi = {10.3390/hydrology13030091},
  url = {https://doi.org/10.3390/hydrology13030091}
}