Improving the identification of pollution source areas with catchment-resolution sensitivity analysis

Xia Li; Ling Du; Shuhui Zhang; Ke Shi; Qichun Yang; Liping Li; Jiakun Jiang; Ze Ren; Xinhui Liu

doi:10.1016/j.envpol.2024.124658

Improving the identification of pollution source areas with catchment-resolution sensitivity analysis

Environ Pollut. 2024 Nov 1:360:124658. doi: 10.1016/j.envpol.2024.124658. Epub 2024 Aug 3.

Authors

Xia Li¹, Ling Du², Shuhui Zhang¹, Ke Shi³, Qichun Yang⁴, Liping Li¹, Jiakun Jiang⁵, Ze Ren⁶, Xinhui Liu⁷

Affiliations

¹ Research and Development Center for Watershed Environmental Eco-Engineering, Beijing Normal University, Zhuhai, 519087, China; State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China; Key Laboratory of Coastal Water Environmental Management and Water Ecological Restoration of Guang-dong Higher Education Institutes, Beijing Normal University, Zhuhai, 519087, China.
² Department of Environmental Science & Technology, University of Maryland, College Park, MD, 20742, USA; Hydrology and Remote Sensing Laboratory, USDA-ARS, Beltsville, MD, 20705, USA.
³ Key Laboratory of Coastal Water Environmental Management and Water Ecological Restoration of Guang-dong Higher Education Institutes, Beijing Normal University, Zhuhai, 519087, China; Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 510632, China.
⁴ Thrust of Earth, Ocean and Atmospheric Sciences, Hong Kong University of Science and Technology (GZ), Guangzhou, 511453, China.
⁵ Center for Statistics and Data Science, Beijing Normal University, Zhuhai, 519087, China.
⁶ State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China.
⁷ Research and Development Center for Watershed Environmental Eco-Engineering, Beijing Normal University, Zhuhai, 519087, China; State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China; Key Laboratory of Coastal Water Environmental Management and Water Ecological Restoration of Guang-dong Higher Education Institutes, Beijing Normal University, Zhuhai, 519087, China. Electronic address: [email protected].

PMID: 39098639
DOI: 10.1016/j.envpol.2024.124658

Abstract

The significant impacts of total nitrogen (TN) and total phosphorus (TP) on riverine ecosystems underscores the critical need to identify the primary nutrient source areas in watersheds. This study aims to unravel the influences of terrain and land use types on mean monthly TN (TNM) and mean monthly TP (TPM) export across varying catchment resolutions in the Qiantang River Watershed of China. The findings of this study illuminated the critical role of topography in understanding nutrient dynamics, wielding a profound influence over water flow patterns and nutrient dispersion. Both land slope and Stream Power Index (SPI) displayed substantial negative correlations (r < -0.6) with TNM and TPM concentrations, whereas the Topographic Wetness Index (TWI) showed positive correlations with the nutrient indexes. In addition to terrain characteristics, impervious land surfaces had a positive correlation with nutrient concentrations, while grassland and forest areas exhibited negative correlations. Results further underscored the substantial influence of catchment resolution on correlations between watershed properties and riverine nutrient concentrations. It was imperative to choose an effective catchment resolution in watershed delineation - not too coarse, nor too fine - to accurately capture the topographic and land use impacts on nutrient dynamics. With the most appropriate catchment size (Catchment 700 km²), the critical pollution source areas for TN and TP pollution were identified, and thus could be used to guide future pollution reduction efforts. The study not only highlights the importance of identifying an appropriate catchment size for water pollution, but also emphasizes the necessity of effectively extracting critical pollution source areas to mitigate water nutrient pollution and increase the ecological integrity of the Qiantang River Watershed.

Keywords: Catchment resolutions; Land use; Pollution source areas; Topography; Total nitrogen; Total phosphorus.

MeSH terms

China
Ecosystem
Environmental Monitoring* / methods
Nitrogen* / analysis
Phosphorus* / analysis
Rivers* / chemistry
Water Pollutants, Chemical* / analysis

Substances

Phosphorus
Nitrogen
Water Pollutants, Chemical