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Title: Integrating terrestrial and aquatic processes toward watershed scale modeling of dissolved organic carbon fluxes

Abstract

Dissolved organic carbon (DOC) is not only a critical component of global and regional carbon budgets, but also an important precursor for carcinogenic disinfection byproducts (DBP) generated during drinking water disinfection process. The lack of process based watershed scale model for carbon cycling has been a limiting factor impeding effective watershed management to control DOC fluxes to source waters. Here, we integrated terrestrial and aquatic carbon processes into the widely tested Soil and Water Assessment Tool (SWAT) watershed model to enable watershed-scale DOC modeling (referred to as SWAT-DOC hereafter). The modifications to SWAT mainly fall into two groups: (1) DOC production in soils and its transport to aquatic environment by different hydrologic processes, and (2) riverine transformation of DOC and their interactions with particular organic carbon (POC), inorganic carbon and algae (floating and bottom). We tested the new SWAT-DOC model in the Cannonsville watershed, which is part of the New York City (NYC) water supply system, using long-term DOC load data (from 1998 to 2012) derived from 1399 DOC samplings. The calibration and verification results indicate that SWAT-DOC achieved satisfactory performance for both streamflow and DOC at daily and monthly temporal scales. The parameter sensitivity analysis indicates that DOC loadsmore » in the Cannonsville watershed are controlled by the DOC production in soils and its transport in both terrestrial and aquatic environments. Further model uncertainty analysis indicates high uncertainties associated with peak DOC loads, which are attributed to underestimation of high streamflows. Therefore, future efforts to enhance SWAT-DOC to better represent runoff generation processes hold promise to further improve DOC load simulation. Overall, the wide use of SWAT and the satisfactory performance of SWAT-DOC make it a useful tool for DOC modeling and mitigation at the watershed scale.« less

Authors:
 [1]; ORCiD logo [2];  [3];  [4];  [3]
  1. Independent consultant, Edmonton, Alberta, CA
  2. BATTELLE (PACIFIC NW LAB)
  3. NYC Dept of Environmental Protection
  4. National Institute of Water & Atmospheric Research Ltd (NIWA), NZ
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1545013
Report Number(s):
PNNL-SA-143356
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Environmental Pollution
Additional Journal Information:
Journal Volume: 249
Country of Publication:
United States
Language:
English
Subject:
Dissolved Organic Carbon, non-point source pollution

Citation Formats

Du, Xinzhong, Zhang, Xuesong, Mukundan, Rajith, Hoang, Linh, and Owens, Emmet M. Integrating terrestrial and aquatic processes toward watershed scale modeling of dissolved organic carbon fluxes. United States: N. p., 2019. Web. doi:10.1016/j.envpol.2019.03.014.
Du, Xinzhong, Zhang, Xuesong, Mukundan, Rajith, Hoang, Linh, & Owens, Emmet M. Integrating terrestrial and aquatic processes toward watershed scale modeling of dissolved organic carbon fluxes. United States. doi:10.1016/j.envpol.2019.03.014.
Du, Xinzhong, Zhang, Xuesong, Mukundan, Rajith, Hoang, Linh, and Owens, Emmet M. Sat . "Integrating terrestrial and aquatic processes toward watershed scale modeling of dissolved organic carbon fluxes". United States. doi:10.1016/j.envpol.2019.03.014.
@article{osti_1545013,
title = {Integrating terrestrial and aquatic processes toward watershed scale modeling of dissolved organic carbon fluxes},
author = {Du, Xinzhong and Zhang, Xuesong and Mukundan, Rajith and Hoang, Linh and Owens, Emmet M.},
abstractNote = {Dissolved organic carbon (DOC) is not only a critical component of global and regional carbon budgets, but also an important precursor for carcinogenic disinfection byproducts (DBP) generated during drinking water disinfection process. The lack of process based watershed scale model for carbon cycling has been a limiting factor impeding effective watershed management to control DOC fluxes to source waters. Here, we integrated terrestrial and aquatic carbon processes into the widely tested Soil and Water Assessment Tool (SWAT) watershed model to enable watershed-scale DOC modeling (referred to as SWAT-DOC hereafter). The modifications to SWAT mainly fall into two groups: (1) DOC production in soils and its transport to aquatic environment by different hydrologic processes, and (2) riverine transformation of DOC and their interactions with particular organic carbon (POC), inorganic carbon and algae (floating and bottom). We tested the new SWAT-DOC model in the Cannonsville watershed, which is part of the New York City (NYC) water supply system, using long-term DOC load data (from 1998 to 2012) derived from 1399 DOC samplings. The calibration and verification results indicate that SWAT-DOC achieved satisfactory performance for both streamflow and DOC at daily and monthly temporal scales. The parameter sensitivity analysis indicates that DOC loads in the Cannonsville watershed are controlled by the DOC production in soils and its transport in both terrestrial and aquatic environments. Further model uncertainty analysis indicates high uncertainties associated with peak DOC loads, which are attributed to underestimation of high streamflows. Therefore, future efforts to enhance SWAT-DOC to better represent runoff generation processes hold promise to further improve DOC load simulation. Overall, the wide use of SWAT and the satisfactory performance of SWAT-DOC make it a useful tool for DOC modeling and mitigation at the watershed scale.},
doi = {10.1016/j.envpol.2019.03.014},
journal = {Environmental Pollution},
number = ,
volume = 249,
place = {United States},
year = {2019},
month = {6}
}