Snowmelt runoff model (SRM) for regulated watersheds with regulation-correction

Area of Science:

• Hydrology
• Water Resource Management
• Environmental Modeling

Background:

• Streamflow simulation in regulated watersheds presents challenges due to altered hydrological processes.
• Existing models like the Snowmelt Runoff Model (SRM) may not accurately capture the effects of flow regulation.
• Accurate streamflow prediction is crucial for effective water resource management and infrastructure operation.

Purpose of the Study:

• To develop and validate an enhanced Snowmelt Runoff Model (E-SRM) for simulating streamflow in regulated watersheds.
• To introduce a parsimonious regulation-correction approach to account for human impacts on river flow.
• To assess the performance of the E-SRM across different calibration and validation periods.

Main Methods:

• The Snowmelt Runoff Model (SRM) was modified into the Expanded SRM (E-SRM) with automated batch processing, nested iterators, and a seasonal divider algorithm.
• A regulation-correction approach was implemented, dividing the watershed into a pristine "daughter" subwatershed and a regulated "mother" watershed.
• The E-SRM was applied to the Morony watershed in Montana, USA, with calibration on the Canyon Ferry subwatershed and validation on the entire Morony watershed.

Main Results:

• The E-SRM demonstrated improved streamflow simulation performance compared to the standard SRM in the regulated Morony watershed.
• Multiple assessment metrics, including Nash-Sutcliffe Efficiency (NSE) and Kling-Gupta Efficiency (KGE), showed significant improvements.
• For instance, NSE values improved from negative to positive ranges (e.g., -0.16 to 0.74) across different scenarios, indicating enhanced model accuracy.

Conclusions:

• The developed E-SRM framework effectively simulates streamflow in regulated watersheds by integrating a novel regulation-correction method.
• The study highlights the substantial impact of flow regulation on hydrological model performance and the necessity of accounting for it.
• The E-SRM offers a valuable tool for advancing research and practical applications in water resource management, particularly in human-altered river systems.