Non-Point Source Pollution Simulation and Best Management Practices Analysis Based on Control Units in Northern China

Area of Science:

• Environmental Science
• Hydrology
• Water Resource Management

Background:

• Non-point source (NPS) pollution poses significant challenges to water quality.
• Effective management requires precise identification of pollution source areas.
• Best Management Practices (BMPs) are crucial for mitigating NPS pollution.

Purpose of the Study:

• To introduce a control unit division method for NPS pollution simulation.
• To analyze the spatial and temporal distribution of NPS pollution in the Guishui River Basin.
• To evaluate the environmental and cost-effectiveness of different BMP scenarios.

Main Methods:

• Utilized the Soil Water Assessment Tool (SWAT) model for NPS pollution simulation.
• Employed a control unit division method to delineate critical pollution source areas.
• Designed and analyzed five distinct BMP scenarios, including vegetated filter strips and grassed waterways.

Main Results:

• Total nitrogen (TN) and total phosphorus (TP) loss are concentrated during the rainy season.
• Pollution hotspots are primarily located in the middle and lower reaches of the Guishui River, comprising 22.34% of the basin.
• The vegetated filter strips (VFS) scenario achieved the highest TN (63.4%) and TP (62.6%) reduction efficiencies.
• Grassed Waterway demonstrated the best cost-effectiveness for TN and TP reduction.

Conclusions:

• The control unit method enhances the identification of critical NPS pollution source areas compared to traditional approaches.
• Implementing BMPs, particularly VFS and Grassed Waterways, offers significant environmental and economic benefits for watershed management.
• This research provides valuable technical support for watershed management decision-making and targeted pollution control strategies.