• Journal of Korean Society of Forest Science
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• v.89 no.3
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• pp.342-355
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• 2000

This study was carried out to reveal the influence of discharge change on matters and stream water quality between pH, EC and dissolved matters obtained by observation of long-term and short-term on stream water quality and separated runoff components from stream water by using HYCYMODEL. From January in 1998 to September in 1999, it was estimated by relationships of character of water quality and discharge for the experimental watershed in Mt. Palgong. The results were summarized as follows : 1. Annual average pH values of stream water in 1998 and in 1999 were 6.48(6.22~6.89) and 6.52(5.75~7.18), respectively. The observed annual average pH values were maintaining identical values in general, but pH values decreased continuously during the four months after thinning in the experimental watershed. So thinning is suspected of the major cause for the decrease. 2. Annual average EC values of stream water in 1998 and in 1999 were $26.69(17.95{\sim}33.5){\mu}S/cm$ and $25.19(17.5{\sim}33.8){\mu}S/cm$, respectively. The observed annual average EC values were maintaining identical values in general. 3. As a result of the comparison of average dissolved ions of rainfall and stream water, $Na^+$, $Mg^{2+}$, $Ca^{2+}$, $Cl^-$, $NO_3{^-}$, and $SO_4{^{2-}}$ showed minus values between incomings and outgoings. $Na^+$ and $NO_3{^-}$ among the dissolved ions of stream water showed the highest concentration out of cations and anions respectively. 4. By the change of pH value in stream water due to rainfall events, pH value decreased with increasing runoff as pH value increased before and after peak flow. 5. By the change of EC value in stream water due to rainfall events, EC value decreased with increasing runoff of first rainfall as EC value changed with runoff before and after peak flow. 6. As the runoff increased, the concentration of $Na^+$, $Ca^{2+}$, $K^+$, total cation, $Cl^-$, and $SO_4{^{2-}}$ in stream water lowered. On the other hand, the runoff decreased, their concentration in stream water tended to get high. But in terms of $NO_3{^-}$ and total anion, they turned out vice versa. $Mg^{2+}$ produced no reaction. 7. The base flow among runoff components separated by using HYCYMODEL influenced greatly on pH, EC, concentration of cation and anion.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.2
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• pp.47-57
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• 2013

This study is to assess the reduction of non-point source pollution loads for rice straw mulching of upland crop cultivation at a watershed scale. For Byulmi-cheon watershed (1.21 $km^2$) located in the upstream of Gyeongan-cheon, the HSPF (Hydrological Simulation Program-Fortran) and SWAT (Soil and Water Assesment Tool), physically based distributed hydrological models were applied. Before evaluation, the model was calibrated and validated using 9 rainfall events. The Nash-Sutcliffe model efficiency (NSE) for streamflow using the HSPF was 0.62~0.76 and the determination coefficient ($R^2$) for water quality (sediment, total nitrogen T-N, and total phosphorus T-P) were 0.72, 0.62, and 0.63 respectively. The NSE for streamflow using the SWAT were 0.43~0.81 and the $R^2$ for water quality (sediment, T-N, and T-P) were 0.54, 0.87, and 0.64 respectively. From the field experiment of 16 rainfall events, the rice straw cover condition reduced surface runoff average 10.0 % compared to normal surface condition. By handling infiltration capacity (INFILT) in HSPF model, the value of 16.0 mm/hr was found to reduce about 10.0 % reduction of surface runoff. For this condition, the reduction effect of sediment, T-N, and T-P loads were 87.2, 28.5, and 85.1 % respectively. By handling soil hydraulic conductivity (SOL_K) in SWAT model, the value of 111.2 mm/hr was found to reduce about 10.0 point reduction of surface runoff. For this condition, the reduction effect of sediment, T-N, and T-P loads were 80.0, 83.2, and 78.7 % respectively. The rice straw surface covering was effective for removing surface runoff dependent loads such as sediment and T-P.

• Journal of Wetlands Research
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• v.14 no.4
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• pp.581-589
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• 2012

Non-point source pollutant is exerting a serious influence on the water quality, since the characteristics of stormwater runoff is varied by the land usage pattern of an area and a basin, and all sorts of pollutants on the earth in rainfall flow into the urban stream. This study estimated EMC of each pollutant to investigate the characteristics of stormwater runoff by separating the urban area as the housing area and industrial area. As a result of the analysis, the first flush effect occurred in the non-point source pollutant of housing area and industrial area, as the runoff concentration gradually reduces after it rapidly increases in the initial rainfall, and in case of the non-point source pollutant the control of first stage rain-water. It is considered to require the continuous follow-up study such as the scale of long-term rainfall event and water quality data, land usage pattern by GIS method, database of topography and geological features, and so forth.

• Journal of Korean Society on Water Environment
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• v.20 no.5
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• pp.415-421
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• 2004

Litter wastes on highway runoff are gradually being considered one of the major pollutants of concern in protecting the integrity of receiving waters for beneficial use. The California State Water Resources Control Board has identified in their 303(d) list at least 36 water bodies where trash or litter is considered a pollutant of concern. The first TMDL adopted by the Region 4 (Los Angeles area) of the California State Water Quality Control Board was for trash in the Los Angeles River. The first flush characteristic study was developed to obtain first flush water quality and litter data from representative stormwater runoff from standard highway drainage outfalls in the Los Angeles area. Total captured gross pollutants in stormwater runoff were monitored at six Southern California highway sites over two years. The gross pollutants were 90% vegetation and 10% litter. Approximately 50% of the litter was composed of biodegradable materials. The event mean concentrations show an increasing trend with antecedent dry days and a decreasing trend with total runoff volume or total rainfall. Event mean concentrations were ranged 0.0021 to 0.259g/L for wet gross pollutants and 0.0001 to 0.027g/L for wet litters. The first flush phenomenon was evaluated and the impacts of various parameters such as rainfall intensity, drainage area, peak flow rate, and antecedent dry period on litter volume and loading rates were evaluated. First flush phenomenon was generally observed for litter concentrations, but was not apparent with litter mass loading rates. Litter volume and loading rates appear to be directly related to peak storm intensity, antecedent dry days and total flow volume.

• Journal of Korean Society on Water Environment
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• v.27 no.5
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• pp.572-579
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• 2011

We have examined the runoff characteristics of nonpoint source (NPS) in fields. Two monitoring sites were equipped with an automatic velocity meter and water sampler. Monitoring was conducted at fields 1 and field 2 during the rainfall event. Ten rainfall-runoff events were monitored and analyzed during the study period. The results show that runoff occurred if daily rainfall and intensity were higher than 40 mm and 1.6 mm/hr except a few extreme rainfall events with very high intensity. Runoff of field 1 was approximately twice of that of field 2. Event mean concentrations (EMC) and pollution load of analyzed water quality indices were also higher in field 2 than in field 1. Especially, TN load from field 2 was $75.4 mg/m^2$ and was about 5 times higher than that from field 1. Analysis of Pearson correlation coefficient of water quality parameter indicates that besides of TN all items in fields 1 have tight relationship respectively (p < 0.01). But those of fields 2 have a significant (p < 0.05). Estimating units loading of NPS, we suggested that variable such as soil texture, rainfall amount and intensity and slope were needed to be considered from agricultural landuses. The results of this study can be used as a basic data in the development and implementation of total maximum daily loads (TMDL) in Korea.

• Journal of the Korea Organic Resources Recycling Association
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• v.30 no.1
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• pp.23-32
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• 2022

In this study, rainfall water outlet water quality monitoring was performed on the C industrial complex to evaluate the characteristics of non-point pollutant runoff from the industrial complex during rainfall and to use it as basic data for calculating the load and unit of non-point pollutant. As a result of the IETD analysis, it was selected as a representative rainfall event for simulating non-point pollutants when the rainfall duration was about 21 hours and the rainfall was 26.44mm. Also as a result of monitoring the flow and water quality survey, the first rainfall was 12.2 mm, the rainfall duration was 12 hr, the number of preceding dry days was 3 days, the second rainfall was 22.1 mm, the rainfall duration was 12 hr, and the number of preceding dry days was 7 days.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.2
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• pp.235-242
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• 2007

Road runoff water includes various heavy metals (zinc, Zn; lead, Pb; copper, Cu; chrome, Cr; cadmium, Cd; etc.) and pathogens (E-coli and coliform). Since these pollutants are significantly harmful to human beings and have negative impact on water streams, numerous studies have been conducted to determine the characterization of these non-point pollutants from road runoff water. However, since these non-point pollutant concentrations vary depending on road traffic, road construction, and road maintenance, measurement of pollutant loadings in different site is necessary to estimate the effect of road runoff water on drinking water source. The objective of this study was to examine the quality of road runoff water from a city bridge in Seoul, Korea. This study was conducted for two years to assess annual discharge pollution loads. In this study, five key heavy metals (Zn, Pb, Cu, Cr, and Cd) and two pathogens (E-coli and coliform) were measured at 18 different events. The pollutant load mass transported was always higher than the corresponding runoff volume for Zn, Cu, and Cd, while Pb and Cr showed similar values between the load mass transported and the corresponding runoff volume. The event mean concentrations were Zn (0.908 mg/L), Pb (0.092 mg/L), Cu (0.141 mg/L), Cr (0.023 mg/L), and Cd (0.006 mg/L). Like Zn, Cu, and Cd, E-coli and coliform values (relatively high in Summer and Fall) are higher at the beginning of each event and decrease afterwards.

• Journal of Environmental Science International
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• v.20 no.3
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• pp.361-372
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• 2011

This study analyzed the characteristics of stormwater runoff by rainfall type in orchard areas for two years. Effluents were monitored to calculate the EMCs and runoff loads of each pollutant. The runoff characteristics for nonpoint sources from vineyards were also inspected based on independent variables that affect runoff such as rainfall and rainfall intensity. The average runoff loads of each pollutant from vineyard_A and vineyard_B were found as follows: BOD 39.13 mg/$m^2$, COD 112.13 mg/$m^2$, TOC 54.98 mg/$m^2$, SS 1,681.8 mg/$m^2$, TN 18.29 mg/$m^2$, and TP 4.06 mg/$m^2$, which indicates that the COD's runoff load was especially high. The average EMCs from vineyard_A and vineyard_B, which represents the quality of rainfall effluent, were also analyzed: BOD 3.5 mg/L, COD 11.5 mg/L, TOC 5.2 mg/L, SS 211.7 mg/L, TN 1.774 mg/L, and TP 0.324 mg/L. This suggested that the COD, as an indicator of organic pollutants, is high in terms of EMCs as well. As rainfall increased, the EMCs of BOD, COD, TOC and SS kept turning upward. At a point, however, the high rainfall brought about dilution effects and began to push down the EMCs. Higher rainfall intensities led to the increase in the EMCs that displays the convergence of rainfall. Low rainfall intensities also raised pollutant concentrations, although the concentrations themselves were slightly different among pollutants.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.4
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• pp.78-88
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• 2003

The land use changes from non-urban areas to urban areas lead to the increased impervious areas, consequently increased direct runoff and higher peak runoff. Urban areas have also been recognized as significant sources of Nonpoint Source (NPS) pollution, while agricultural activities have been known as the primary sources of NPS pollution. Many features of the L-THIA/NPS GIS, L-THIA/NPS WWW system have been enhanced to provide easy-to-use system. The L-THIA model was applied to the Little Eagle Creek (LEC) watershed in Indiana to evaluate the accuracy of the model. The L-THIA/NPS GIS estimated yearly direct runoff values match the direct runoff separated from U.S. Geological Survey stream flow data reasonably. The $R^2$ and Nash-Sutcliffe values are 0.67 and 0.60, respectively. The L-THIA estimated runoff volume and total nitrogen loading for each land use classification in the LEC watershed were computed. The estimated runoff volume and total nitrogen loading in the LEC watershed increased by 180% and 270% for the 20 years. Urbanized areas -"Commercial", "High Density Residential", and "Low Density Residential"- of the LEC watershed made up around 68% of the 1991 total land areas, however contributed more than 92% of average annual runoff and 86% of total nitrogen loading. Therefore, it is essential to consider the impacts of land use change on hydrology and water quality in land use planning of urbanizing watershed.nning of urbanizing watershed.

• Journal of Korean Society on Water Environment
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• v.23 no.5
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• pp.620-627
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• 2007

In this study a general analysis method for watersheds with the entire runoff conditions and corresponding water quality is proposed and its applicability based on the currently available information is investigated. Using the 8-day-interval data set of runoff and water quality observed by Nakdong River Environment Research Center, the flow duration curve and discharge-load relation curve for each unit watershed are established, then the load duration curve is finally constructed. This paper discusses how the load duration curve can be used in the assessment of TMDL. The entire Nakdong river watershed is also divided into prior managing areas of point sources or non-point sources in a way of general management. It is thought that LDC can be a great tool for visualizing overall probabilities of current water quality and thus for the TMDL management.