Evaluating the risks of spatial and temporal changes in nonpoint source pollution in a Chinese river basin

Area of Science:

• Environmental Science
• Water Resource Management
• Ecosystem Health

Background:

• Nonpoint source (NPS) pollution poses significant risks to watershed management.
• Evaluating NPS pollution requires robust risk assessment models.
• Source-sink landscape theory provides a framework for understanding pollution dynamics.

Purpose of the Study:

• To propose and apply the Nonpoint Source Pollution Risk Index (NSPRI) model.
• To analyze spatial and temporal variations in nitrogen and phosphorus loss risks.
• To identify the influence of basin characteristics on nutrient loss risk.

Main Methods:

• Development and application of the Nonpoint Source Pollution Risk Index (NSPRI) model.
• Analysis of land use changes from 2000 to 2018.
• Correlation and redundancy analyses with the Soil and Water Assessment Tool (SWAT) model.

Main Results:

• Extremely high-risk areas decreased, and the average NSPRI dropped, indicating risk reduction.
• NSPRI showed increased spatial clustering and improved ecological balance.
• Land use composition and landscape patterns were more influential on nutrient loss risk than hydrological factors.

Conclusions:

• The NSPRI model effectively assesses NPS pollution risks in watershed management.
• Land use composition is a key driver of nutrient loss risk.
• The source-sink landscape theory framework supports scientific NPS pollution control strategies.