Related Experiment Video
Updated: Jan 31, 2026
12:50
Continuous Instream Monitoring of Nutrients and Sediment in Agricultural Watersheds
Published on: September 26, 2017
11.9K
Watershed diffuse pollution dynamics and response to land development assessment with riverine sediments.
Wei Ouyang1, Xin Hao1, Li Wang1
1State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China.
The Science of the Total Environment
|January 2, 2019
Summary
Sediment cores reveal long-term pollution trends. Total phosphorus (TP) sedimentation flux accurately reflects diffuse pollution, unlike total nitrogen (TN), especially after land use changes in agricultural watersheds.
Area of Science:
- Environmental Science
- Geochemistry
- Hydrology
Background:
- Sediment cores act as archives of diffuse pollution history.
- Understanding pollutant accumulation is key to assessing watershed management strategies.
Purpose of the Study:
- To establish a quantitative relationship between pollutant sedimentation flux in sediment cores and diffuse pollution loads.
- To evaluate the effectiveness of sediment cores in tracking historical changes in total nitrogen (TN) and total phosphorus (TP) pollution.
- To assess the impact of land use changes on diffuse pollution dynamics within an agricultural watershed.
Main Methods:
- Sediment cores were collected from an agricultural watershed and dated using 210Pb isotope radioactivity.
- Total nitrogen (TN) and total phosphorus (TP) sedimentation fluxes were calculated using Constant Rate of Supply (CRS) and Constant Initial Concentration (CIC) models.
- Watershed pollutant loads were simulated using the Soil and Water Assessment Tool (SWAT), and relationships were analyzed using linear regression.
Main Results:
- Total phosphorus (TP) sedimentation flux showed a strong positive correlation with simulated diffuse loads (R² = 0.600 and 0.664) using the CRS model.
- TP sedimentation flux proved more effective than TN in reflecting long-term diffuse pollution dynamics.
- Land use changes, specifically paddy land expansion, altered the spatial distribution of TN and TP sedimentation fluxes, with TP flux differences narrowing and TN flux gaps widening.
Conclusions:
- Sediment core analysis, particularly TP flux, provides a reliable method for assessing long-term diffuse pollution in agricultural watersheds.
- The study highlights the differential response of nitrogen and phosphorus to land use changes.
- Integrating sediment core data with watershed modeling offers valuable insights into historical environmental changes and impacts of land management.
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