Assessment of changes in riverine nitrate in the Sesan, Srepok and Sekong tributaries of the Lower Mekong River Basin

Authors

Chanta Oeurng, University of Cantebury
Thomas A. Cochrane, University of Canterbury
Mauricio E. Arias, University of South FloridaFollow
Bikesh Shrestha, University of Canterbury
Thanapon Piman, Stockholm Environmental Institute

Document Type

Article

Publication Date

12-2016

Keywords

Nitrate load, SWAT, Mekong, Southeast Asia, Climate change

Digital Object Identifier (DOI)

https://doi.org/10.1016/j.ejrh.2016.07.004

Abstract

Changes in nitrates are of particular concern in tropical regions undergoing rapid development, as these changes may affect local and downstream riverine ecosystems. This study assessed the spatial and temporal differences in nitrate loads within the Sesan, Srepok, and Sekong (3S) Rivers, the largest tributaries of the Mekong River. Simulation results from a flow and nitrate calibrated SWAT model show large differences in year-to-year nitrate loads, a strong seasonality, and clear variability patterns in monthly nitrate loads in the 3S outlet during the wet season. The annual total nitrate loading from the 3S Rivers account for approximately 30% of the total nitrate load of the Mekong River at Pakse. Nitrate loads during the rainy season accounts for 79% of the total annual load into the Mekong River. The Sesan, Sekong, and Srepok basins have average nitrate yields of 400, 330, and 290 kg N/km², respectively, which is comparable with other forested catchments, but much lower than agriculture dominated catchments in the tropics. Simulations of three future climate scenarios show little variability in annual nitrate loadings under current land use/land cover (LULC), but seasonal difference in nitrate loading during rainy months was observed. Further research is needed to estimate nitrate loads in the 3S basin as influenced by LULC change and dam development, which may potentially result in complex changes to local and downstream riverine ecosystems.

Rights Information

This work is licensed under a Creative Commons Attribution 4.0 License.

Was this content written or created while at USF?

Yes

Citation / Publisher Attribution

Journal of Hydrology: Regional Studies, v. 6, p. 95-111

Scholar Commons Citation

Oeurng, Chanta; Cochrane, Thomas A.; Arias, Mauricio E.; Shrestha, Bikesh; and Piman, Thanapon, "Assessment of changes in riverine nitrate in the Sesan, Srepok and Sekong tributaries of the Lower Mekong River Basin" (2016). Civil and Environmental Engineering Faculty Publications. 44.
https://digitalcommons.usf.edu/egx_facpub/44