[Risk Assessment Method of Non-point Source Pollution Output for Watershed Using High Resolution Data]

Area of Science:

• Environmental Science
• Hydrology
• Water Quality Management

Background:

• Non-point source pollution is a primary driver of water quality decline in Chinese reservoirs.
• The Panjiakou Reservoir faces significant challenges from water quality deterioration due to pollution.

Purpose of the Study:

• To develop and apply a high-resolution, data-driven method for assessing non-point source pollution output risk.
• To analyze the temporal and spatial distribution of pollution risk in the Panjiakou Reservoir basin.
• To identify key factors influencing pollution risk, including precipitation, terrain, land use, and human activities.

Main Methods:

• Improved classical output risk model incorporating precipitation and terrain factors.
• Utilized high-resolution satellite data: GPM for precipitation and GF-6 for imagery.
• Established a data-driven risk assessment framework for non-point source pollution.

Main Results:

• High non-point source pollution output risk identified in the Panjiakou Reservoir basin in 2018.
• Areas with higher/highest nitrogen pollution risk covered approximately 70.6% of the watershed.
• Higher phosphorus pollution risk affected about 21.9% of the watershed.
• Pollution risk peaked from April to September, correlating with precipitation patterns.
• Upstream cultivated land and downstream urban areas exhibited higher pollution risk due to agricultural and human activities.

Conclusions:

• The developed method effectively assesses non-point source pollution risk with high spatial and temporal resolution.
• Agricultural production and urban activities are significant contributors to pollution risk.
• Recommendations include optimizing fertilization, planning landscape source-sinks, and establishing vegetation buffer zones to mitigate pollution.