A dynamic bidirectional coupling model for watershed water environment simulation based on the multi-grid technique

Area of Science:

• Environmental science
• Water resource management
• Computational modeling

Background:

• Water pollution is a significant global challenge requiring effective modeling tools.
• Existing water environment models have limitations in efficiency and accuracy.
• Basin-scale water pollution studies necessitate integrated modeling approaches.

Purpose of the Study:

• To develop and validate a novel dynamic bidirectional coupling model (E-DBCM) for water environment simulation.
• To enhance computational efficiency and numerical accuracy in water pollution modeling.
• To assess the water environment of the Yanqi River Basin using the developed model.

Main Methods:

• Developed a dynamic bidirectional coupling model (E-DBCM) integrating an upland watershed module (UWSM) and a 2D downstream waterbody module (DWBM).
• Employed the multi-grid technique for spatial discretization with varying grid sizes and time steps.
• Validated the model using two test cases and applied it to the Yanqi River Basin.

Main Results:

• The E-DBCM demonstrated satisfactory computing efficiency and acceptable numerical accuracy.
• The multi-grid technique increased computational efficiency by 90%.
• Application to the Yanqi River Basin showed a maximum percent bias of 10.31%, confirming model reliability.

Conclusions:

• The E-DBCM is a reliable and efficient tool for water environment modeling, meeting engineering demands.
• Water pollution in the Yanqi River Basin is severe, particularly during flood seasons.
• Improved water environment treatment and strengthened protection measures are crucial for the Yanqi River Basin.