• Journal of Korean Society on Water Environment
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• v.30 no.2
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• pp.212-219
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• 2014

In this study, a land pollutant load calculation method in TMDLs was improved to consider climate change scenarios. In order to evaluate the new method, future change in rainfall patterns was predicted by using SRES A1B climate change scenarios and then post-processing methods such as change factor (CF) and quantile mapping (QM) were applied to correct the bias between the predicted and the observed rainfall patterns. Also, future land pollutant loads were estimated by using both the bias corrected rainfall patterns and the enhanced method. For the results of bias correction, both methods (CF and QM) predicted the temporal trend of the past rainfall patterns and QM method showed future daily average precipitation in the range of 1.1~7.5 mm and CF showed it in the range of 1.3~6.8 mm from 2014 to 2100. Also, in the result of the estimation of future land pollutant loads using the enhanced method (2020, 2040, 2100), TN loads were in the range of 4316.6~6138.6 kg/day and TP loads were in the range of 457.0~716.5 kg/day. However, each result of TN and TP loads in 2020, 2040, 2100 was the same with the original method. The enhanced method in this study will be useful to predict land pollutant loads under the influence of climate change because it can reflect future change in rainfall patterns. Also, it is expected that the results of this study are used as a base data of TMDLs in case of applying for climate change scenarios.

• Journal of Korean Society on Water Environment
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• v.28 no.6
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• pp.819-832
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• 2012

HSPF model based on BASINS was applied for the Hwaseong Reservoir watershed (HRW) to evaluate the feasibility of water quality management. The watershed was divided into 45 sub-basins considering various watershed environment. Streamflow was calibrated based on the measured meteorological data, discharge data of treatment plants and observed streamflow data for 2010 year. Then the model was calibrated against the field measurements of water qualities, including BOD, T-N and T-P. In most cases, there were reasonable agreements between observed and predicted data. The validated model was used to analyze the characterization of pollutant load from study area. As a result, Non-point source pollutant loads during the rainy season was about 66~78% of total loads. In rainy-season, water quality parameters depended on precipitation and pollutant loads patterns, but their concentration were not necessarily high during the rainy season, and showed a decreasing trend with increasing water flow. As another result of evaluation for load duration curves, in order to improve water qualities to the satisfactory level, the watershed managements considering both time-variant and pollution sources must be required in the HRW. Overall, it was found that the model could be used conveniently to assess watershed characteristics and pollutant loads in watershed scale.

• Journal of Korean Society on Water Environment
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• v.27 no.5
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• pp.597-604
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• 2011

This research analyzed the runoff patterns and estimated unit loads of selected pollutatnts using monitored data conducted for three years in a bridge area. Three estimating methods; the arithmetic average method, the regression method and the rainfall class method were used to estimate the unit load. Results of three estimating methods were compared with the unit pollutant loads from landuses in Korea and the unit pollutant loads from urban watersheds in Milwaukee, USA. Unit load using the arithmetic mean method were found to be overestimated. In terms of TSS, unit loads of two estimate were half lower than that of USA. Estimated TN and TP unit loads of three estimate were lower than that of Ministry of Environment in Korea.

• Journal of Korean Society on Water Environment
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• v.22 no.2
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• pp.244-249
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• 2006

Natural environment of Weolgokri watershed has been well preserved as a traditional agricultural watershed. A year record of streamflow, $NO_3-N$, T-N and T-P concentrations data (April 2004 - Mar. 2005) were examined to estimate annual and seasonal patterns of pollutant loads in streamflow and baseflow from the agricultural watershed. To estimate pollutant loads from baseflow, baseflow component was separated from streamflow using the digital filter method in the Web-based Hydrograph Analysis Tool system and loads of $NO_3-N$, T-N and T-P from streamflow and baseflow were evaluated. The $NO_3-N$, T-N, and T-P loads from streamflow were 13.85 kg/ha, 45.92 kg/ha and 1.887 kg/ha, respectively, while corresponding loads from baseflow were 7.43 kg/ha, 24.70 kg/ha, 0.582 kg/ha, respectively. It was found that $NO_3-N$ and T-N loads were contributed slightly more by the baseflow (53% and 53% of Total-loads) than by the direct runoff (47% and 47% of Total loads). However, only 30% of total T-P load was contributed by the baseflow. It is recommended that one needs to assess pollutant load contribution by the baseflow to identify appropriate pollution control strategies for an effective watershed management.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.580-585
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• 2005

Natural environment of Weolgok-ri watershed has been well preserved as a traditional agricultural watershed. A year record of streamflow, $NO_3-N$, T-N and T-P concentrations data(Apr, 2004-Mar. 2005) was examined to estimate annual and seasonal patterns of pollutnat loads in streamflow and baseflow from the agriculture watershed. To estimate pollutant loads from baseflow, baseflow component from total stream flow was seperated using digital filter method in the Web-based Hydrograph Analysis Tool system. Loads of $NO_3-N$, T-N and T-P from streamflow and baseflow were evaluated to investigate pollutant loads contribution by baseflow. The $NO_3-N$, T-N, and T-P loads from streamflow were 13.85 kg/ha, 45.92 kg/ha and 1.887 kg/ha, respectively. $NO_3-N$, T-N and T-P loads from baseflow were 7.43 kg/ha, 24.70 kg/ha, 0.582 kg/ha, respectively. It was found that $NO_3-N$ and T-N loads were contributed by the baseflow(53% and 53% of Total-loads) than the direct runoff(47% and 47% of Total loads). However, only 30% of total T-P was contributed by the baseflow. It is recommended that one needs to assess pollutant load contribution by the baseflow to identify appropriate control strategies for effective watershed management.

• The Journal of Engineering Research
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• v.8 no.1
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• pp.107-118
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• 2006

The difficulties to build a 3-dimensional water quality model for the coastal water quality improvement and the environmental recovery estimation are the lack of periodic observed data and the many problems to observe continuously. I observed the rainfall and non-point pollutants outflow patterns in Jinhae-Masan basin as mid-step researches for the water quality simulation and management method development in a coastal area. I applied Landsat image system and Geographic Information System to analyze the runoff and non-point pollutants outflow patterns. A water quality simulation model (SWMM) applied to Jinhae-Masan basin with results of the land use distribution, non-point pollution loads, and watershed informations from GIS(IDRISI used). I proposed some improved survey and GIS application methods reflect upon the pollutant characteristics from the observed non-point pollutant outflow patterns.

• Journal of Korean Society on Water Environment
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• v.26 no.4
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• pp.654-663
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• 2010

Attention has increasingly focused on the pollutant load discharged from rural area since the enforcement of total maximum daily loads (TMDLs) in korea. As one of the methods to control the inflow of pollutant load during wet weather events, local governments are attempting to apply non-point source control facility. To design those facilities appropriately, it is essential to understand the runoff characteristics of pollutants such as TSS, $BOD_5$, $COD_{Cr}$, TP and TN. In the paper, the quantitative analyses for pollutant runoff characteristics were examined in a small rural watershed with the area of about 53 hectares. For a dry weather day and wet weather events, variation patterns of dry weather flow and runoff characteristics of wet weather flows were monitored and investigated. The runoff model using XP-SWMM reflecting the landuse types of the watershed in detail was simulated to perform the sensitivity analyses for several factors influencing on their hydrograph and pollutographs. As a result, for the case of medium and small rainfall events (i. e. total rainfall of 35.8 and 17.5 mm), the impervious area including green house, roof and road which covers relatively low portion of total area (i. e. 16%) caused substantial first flush and the majority of total runoff load. Therefore, it has been concluded that the runoff characteristics of each pollutant and distribution of impervious area should be considered for the establishment of the control strategy of non-point pollutant runoff at a rural area.

• Journal of Korean Society on Water Environment
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• v.26 no.5
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• pp.860-870
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• 2010

Long term monthly monitoring data showed that the water quality of streams flowing into Lake Paldang has been improved by various strategy for water. However, the effect of quality on Lake Paldang is still insufficient because of nonpoint source from watershed. In order to evaluate quantifying methods for pollution source and make a suggestion on improvements, Storm Water Management Model (SWMM) was constructed by using data set from the water quality and streamflow monitoring network in the Kyoungan watershed for Total Maximum Daily Loads (TMDLs). Load duration curve (LDC) based on the result of the Kyoungan watershed SWMM indicated that the water quality criterion on $BOD_5$ was often exceeded in up-stream than down-stream. From flowrate-load correlation curve, SS load significantly increased as streamflow increases. 75.3% of streamflow and 62.1% of $BOD_5$ loads is discharged especially in the zone of high flows, but monitoring data set didn't provide proper information about the conditions and the patterns associated with storm events. Therefore, it is necessary to acquire representative data set for comparing hydrograph and pollutograph through monitoring experimental watershed and to establish methods for quantifying point and nonpoint source pollutant loads.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.241-241
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• 2021

Recent developments recommend the use of SSS to prevent combined sewer overflows and reduce excessive pollutant deposition in the receiving waters; however, other studies also suggest that SSS have minimal or no advantage over CSS in terms of reducing the pollutant loads being discharged in natural waterways. This study was conducted to evaluate the effectiveness of employing SSS in improving the water quality of the rivers in Okcheon-gun, South Korea. The former combined sewer outfalls (CSOs) were monitored to determine the presence of illicit connections or leaks in the newly-established SSS. Dry and wet-day monitoring was conducted alongside the collection of water samples on 14 points along the reach of the rivers and four former CSOs to determine water quality changes and patterns of pollutant loading. Among the 34 former CSOs in the study area, eight former CSOs exhibited dry-day discharges, implying the possibility of having illicit connections, leaks, or illegal wastewater discharge in the system. Moreover, relatively high biochemical oxygen demand (BOD) chemical oxygen demand (COD) concentrations, ranging from 4.8 mg/L to 24.9 mg/L and 6.4 mg/L to 10.1 mg/L, respectively were observed on three out of the four monitored CSOs. Fluctuations in the pollutant concentrations in the different monitored points along the river was also observed due to the presence of pipes discharging polluted water. Ultimately, further studies are necessary to identify the sources of dry-day discharges in the CSOs to successfully improve the water quality of the rivers in the area.

• Korean Journal of Ecology and Environment
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• v.42 no.2
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• pp.200-211
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• 2009

A mathematical modeling program called Soil and Water Assessment Tool (SWAT) developed by USDA was applied to Kyongan stream watershed. It was run under BASINS (Better Assessment Science for Integrating point and Non-point Sources) program, and the model was calibrated and validated using KTMDL monitoring data of 2004${\sim}$2008. The model efficiency of flow ranged from very good to fair in comparison between simulated and observed data and it was good in the water quality parameters like flow range. The model reliability and performance were within the expectation considering complexity of the watershed and pollutant sources. The results of pollutant loads estimation as yearly (2004${\sim}$2008), pollutant loadings from 2006 were higher than rest of year caused by high precipitation and flow. Average non-point source (NPS) pollution rates were 30.4%, 45.3%, 28.1% for SS, TN and TP respectably. The NPS pollutant loading for SS, TN and TP during the monsoon rainy season (June to September) was about 61.8${\sim}$88.7% of total NPS pollutant loading, and flow volume was also in a similar range. SS concentration depended on precipitation and pollution loading patterns, but TN and TP concentration was not necessarily high during the rainy season, and showed a decreasing trend with increasing water flow. SWAT based on BASINS was applied to the Kyongan stream watershed successfully without difficulty, and it was found that the model could be used conveniently to assess watershed characteristics and to estimate pollutant loading including point and non-point sources in watershed scale.