Simulation of 10-day Irrigation Water Quality Using SWAT-QUALKO2 Linkage Model

Abstract

The objectives of this study were to develop a linked watershed-waterbody modeling system and to assess the impacts of indirect wastewater reuse on irrigation water quality. The Osan stream watershed within Gyeonggi-do of South Korea was selected for this study. The linked modeling system was composed of the SWAT (Soil and water assessment tool) and QUALKO2 models. The SWAT model was calibrated and validated using the stream discharge and water quality data from 2010 to 2011. Runoff and non-point source pollutants from each subbasin and stream discharge from 1980 to 2009 were simulated by the SWAT model and applied to the QUALKO2 model. The QUALKO2 model was calibrated and validated under the conditions of low water and normal discharges, respectively. Finally, The 10-day irrigation water quality from April to September was simulated. The statistical measures of coefficient of determination (R 2 ), reliability index (RI), and efficiency index (EI) were used to evaluate the system performance. The R 2 , RI and EI values ranged from 0.5 to 1.0, 1.03 to 1.92, and -35.03 to 0.95, respectively. The 10-day irrigation water quality showed the concentrations of BOD and coliform exceeded the water quality guidelines for wastewater reuse. The linked modeling system can be a useful tool to estimate non-point source pollutant loads in watershed and to control the water quality of effluent from a wastewater treatment plant and irrigation water in the downstream waterbody.

Reuse of Agriculture Drainage Water in a Mixed Land-Use Watershed

“…The QAUL2Kw model was designed for a population size of 100 with 100 generations of evolution [22]. The calibrated parameters values will be the default values for now or same as presented in [23]. For calibration, parameters for the Osan drain QUAL2Kw model using data sets from January 2015 to July 2015.…”

Predicting the Occurrence of Marine Infectious Diseases in the Coastal Areas of South Korea

“…Pathogen prediction studies in South Korea were conducted on Vibrio sp. (KDCA, 2012), watershed and river E. coli (Kim et al, 2012), and marine E. coli (NIFS, 2022).…”

Irrigation Water Quality Standards for Indirect Wastewater Reuse in Agriculture: A Contribution toward Sustainable Wastewater Reuse in South Korea

“…In addition, when using treated wastewater for rice paddy irrigation, the water showed a significant level of salinity compared to conventional irrigation water, and total coliform concentration surpassed the levels of the water quality standards for direct wastewater reuse [20,21]. Previous studies suggest that the quality of irrigation water from streams fails to meet the agricultural water quality standards due to the effects of WWTP effluent [14,22]; thus, the water quality needs to be managed to ensure safe and sound crop production.…”