강성원 Sung Won Kang , 이재영 Jai Young Lee , 김석구 Seog Ku Kim

DOI: Vol.27(No.4) 391-396, 2011

Recently it revealed that urban runoff was one of the major source that contaminates the river, lake and estuary because it contains toxic compounds such as heavy metals and Poly Aromatic Hydrocarbons (PAH5) as well as suspended solids, organic compounds and nutrients. The engineered polymetric media in this research were developed for reducing pollutants in urban runoff and would be used to be charged in the storm water treatment equipment. The engineered media that were composed of the polypropylene was foamed to have the buoyancy and then shattered by mechanical for the efficient filtration, In this study, Spherical Expanded Polypropylene Media (SEPM), Crushed Polypropylene Media (CPM), Large Crushed Expanded Polypropylene Media (LCEPM), Small Crushed Expanded Polypropylene Media (SCEPM) were made from polypropylene. Surface characteristics of the developed media were determined by scanning electron microscopy analyses. Also, removal efficiencies of SS, CODcr in the artificial road runoff and the bed headloss by media and particle pollutants captured by media were examined. Results on the surface characteristics of media indicated that SCEPM had the largest specific surface area, 0.80 ㎡/g, the lowest specific gravity, 0.091, and the biggest porosity, 0.63, because of crushing the media at the process of manufacturing. And the SCEPM`s removal efficiencies of TSS and CODcr in the artificial road runoff were 92.9% and 83.6%. respectively and the headloss of SCEPM was the least of them.

Buoyant media, Expanded polypropylene, Filtration. Impervious surface, Non-point source

김태원 Tae Won Kim , 길경익 Kyung Ik Gil

DOI: Vol.27(No.4) 397-404, 2011

This research investigates the runoff characteristics of refractory organic matters from Kyongan river watershed. Samples were taken 27 times during dry season, 4 times during rain events and analyzed into flow rate, Dissolved Organic Carbon (DOC), Particulate Organic Carbon (POC), Refractory Dissolved Organic Carbon (R-DOC). Refractory Particulate Organic Carbon (R-POC). R-DOC during dry season was the lowest in winter and showed a rising tendency in spring and R-POC changes less than R-DOC. The mass loading of Refractory Total Organic Carbon (R-TOC) in summer takes approximately 80% of 1 year mass loading. During rainy season, EMC of R-DOC was similar to R-DOC in dry season. But maximum EMC of R-POC was 12 times higher than that of R-POC in dry season. Results of the survey show that enhanced management of R-DOC in dry season and R-POC in rainy season is needed.

Dry season, Rain events, Refractory dissolved organic carbon, R-DOC, Refractory particulate organic carbon, R-POC

김희원 Hee Won Kim , 신연주 Yeon Ju Sin , 최정헌 Jung Heon Choi , 강현우 Hyun Woo Kang , 류지철 Ji Chul Ryu , 임경재 Kyoung Jae Lim

DOI: Vol.27(No.4) 405-412, 2011

Increased Non-permeable areas which have resulted from civilization reduce the volume of groundwater infiltration that is one of the important factors causing water shortage during a dry season. Thus, seeking the efficient method to analyze the volume of groundwater in accurate should be needed to solve water shortage problems. In this study, two different watersheds were selected and precipitation, soil group, and land use were surveyed in a particular year in order to figure out the accuracy of estimated infiltration recharge ratio compared to Web-based Hydrograph Analysis Tool (WHAT), The volume of groundwater was estimated considering Antecedent soil Moisture Condition (AMC) and Curve Number (CN) using Long Term Hydrologic Impact Assessment (L-TH1A) model. The results of this study showed that in the case of Kyoung-an watershed, the volume of both infiltration and baseflow seperated from WHAT was 46.99% in 2006 and 33.68% in 2007 each and in Do-am watershed the volume of both infiltration and baseflow was 33.48% in 2004 and 23.65% in 2005 respectively. L-TFIIA requires only simple data (i.e., land uses, soils, and precipitation) to simulate the accurate volume of groundwater. Therefore, with convenient way of L-TKIA, researchers can manage watershed more effectively than doing it with other models. L-THIA has limitations that it neglects the contributions of snowfall to precipitation. So, to estimate more accurate assessment of the long term hydrological impacts including groundwater with L-THIA, further researches about snowfall data in winter should be considered.

Base runoff, Direct runoff, Infiltration, L-THIA, NRCS-CN, WHAT

정세웅 Se Woong Chung , 이정현 Jung Hyun Lee , 류인구 In Gu Ryu

DOI: Vol.27(No.4) 413-424, 2011

The study was aimed to evaluate the applicability of a three-dimensional (3D) hydrodynamic and water quality model, ELCOM-CAEDYM for Yongdam Reservoir, Korea. The model was applied for the simulations of hydrodynamics, thermal stratification processes, stream density flow propagation, and water quality parameters including dissolved oxygen, nutrients, organic materials, and algal biomass (chl-a) for the period of June to December, 2006. The field data observed at four monitoring stations (ST1∼ST4) within the reservoir were used to validate the models performance. The model showed reasonable performance nevertheless low frequency boundary forcing data were provided, and well replicated the physical, chemical, and biological processes of the system. Simulated spatial and temporal variations of water temperature, nutrients, and chl-a concentrations were moderately consistent with the field observations. In particular, the model rationally reproduced the succession of different algal species; i.e., diatom dominant during spring and early summer, after then cyanobacteria dominant under warm and stratified conditions. ELCOM-CAEDYM is recommendable as a suitable coupled 3D hydrodynamic and water quality model that can be effectively used for the advanced water quality management of large stratified reservoirs in Korea.

ELCOM-CAEDYM, Hydrodynamic, Water Quality, Yongdam reservoir

최재완 Jae Wan Choi , 신민환 Min Hwan Shin , 천세억 Se Uk Cheon , 신동석 Dong Seok Shin , 이성준 Sung Jun Lee , 문선정 Sun Jung Moon , 류지철 Ji Cheol Ryu , 임경재 Kyoung Jae Lim

DOI: Vol.27(No.4) 425-432, 2011

To control non-point source pollution at a watershed scale, rainfall-runoff characteristics from forest watersheds should be investigated since the forest is the dominant land use in Korea. Long-term monitoring would be an ideal method. However, computer models have been utilized due to limitations in cost and labor in performing long-term monitoring at the watersheds. In this study, the Geo-spatial interface to the Water Erosion Prediction Project (GeoWEPP) model was evaluated for its runoff prediction from a coniferous forest dominant watersheds. The R2 and the NSE for calibrated result comparisons were 0.77 and 0.63, validated result comparisons were 0.92, 0.89, respectively. These comparisons indicated that the GeoWEPP model can be used in evaluating rainfall-runoff characteristics. To estimate runoff changes from a coniferous forest watershed with various cover degree scenarios, ten cover degree scenarios (10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%) were run using the calibrated GeoWEPP model. It was found that runoff increases with decrease in cover degree. Runoff volume was the highest (206,218.66 m3) at 10% cover degree, whereas the lowest (134,074.58 m3) at 100% cover degree due to changes in evapotranspiration under various cover degrees at the forest. As shown in this study, GeoWEPP model could be efficiently used to investigate runoff characteristics from the coniferous forest watershed and effects of various cover degree scenarios on runoff generation.

Cover degree, Forest, GeoWEPP, Runoff

길경익 Kyung Ik Gil , 신지웅 Ji Woong Shin , 허진 Jin Hur

DOI: Vol.27(No.4) 433-437, 2011

The study is conducted to evaluate loading of organic matter as seasonal changes during non-storm period into Lake Paldang which is used to a major drinking water source. Samples were taken in Lake Paldang intake during non-storm period and were analyzed loading of organic matter. From the results of the survey, improving of the water quality showed remarkable tendency depending on the changing periods from summer to fall and from fall to winter. Dilution effect from the increase of base run-off caused by the concentrated rainfall in rainy season, the characteristics of Korea``s climate seems to have to be the reason. On the other hand, deteriorating of the water quality showed tendency depending on the changing periods from winter to spring and from spring to summer. Increase of Cyanobacteria etc. is explained by seasonal effects which are a small amount of the rainfall in winter and spring and gradational increase of water temperature.

Lake Paldang, Loading of organic matter, Non-storm period, Seasonal changes

김희진 Hee Jin Kim , 김동수 Dong Su Kim

DOI: Vol.27(No.4) 438-444, 2011

Magnesium is one of the abundant natural resources in the earth crust and seawater, which is directly related to various organisms activities interconnecting with water-rock system. In aqueous system, magnesium is known to predominantly exist in the form of Mg2+ ion which is verified in its Eh-pH diagram. When it is at equilibrium in aqueous system, temperature takes an essential role to complete equilibrium states. This study represents the change of the stable region of magnesium ion according to temperature, and how the consequences would affect aquatic organisms. It was revealed that there is a noticeable tendency shrinking the stable region of magnesium ion in a diagram as temperature increases, and as a result, aquatic bio-species presumably have difficulties to absorb the nutrient. Also, it was considered that the water system would be acidified by decreasing alkalinity.

Alkalinity, Eh-pH diagram, Magnesium ion, Stable region

전지혜 Ji Hye Jeon , 정세웅 Se Woong Chung , 박형석 Hyung Seok Park , 장정렬 Jeong Ryeol Jang

DOI: Vol.27(No.4) 445-460, 2011

The objective of this study was to construct and assess the applicability of the EFDC model for Saemangeum Reservoir as a 3D hydrodynamic and water quality modeling tool that is necessary for the effective management of water quality and establishment of conservation measures. The model grids for both reservoir system only and reservoir-ocean system were created using the most recent survey data to compare the effects of different downstream boundary conditions. The model was applied for the simulations of temperature, salinity, water quality variables including chemical oxygen demand (COD), chlorophyll-a (Chl-a), phosphorus and nitrogen species and algal biomass, and validated using the field data obtained in 2008. Although the model reasonably represented the temporal and spatial variations of the state variables in the reservoir with limited boundary forcing data, the salinity level was underestimated in the middle and upstream of the reservoir when the flow data were used at downstream boundaries; Sinsi and Garyuk Gates. In turn, the error caused to increase the bias of water quality simulations, and inaccurate simulation of density flow regime of river inflow during flood events. It is likely because of the loss of momentum of sea water intrusion at downstream boundaries. In contrast to flow boundary conditions, the mixing between sea water and freshwater was well reproduced when open water boundary condition was applied. Thus, it is required to improve the downstream boundary conditions that can accommodate the real operations of the sluice gates.

3D hydrodynamic and water quality modeling, EFDC, Model evaluation, Saemangeum reservoir

이병철 Byeong Cheol Lee , 안조환 Jo Hwan Ahn , 이정훈 Jung Hun Lee , 배우근 Woo Keun Bae

DOI: Vol.27(No.4) 461-466, 2011

The feasibility of utilizing food waste leachate as an external carbon source was tested to enhance biological nutrient removal from an industrial wastewater with an average flow rate of 164,800 m3/d and a low carbon/nitrogen ratio of 2.8. A considerable improvement in the removal of nitrogen and phosphorus was observed when a certain amount of the leachate, ranging from 70 to 142 m3/d, was supplemented to the biological industrial wastewater treatment process. The addition of the leachate led to an increase in the BOD/N ratio (4.5) and the removal efficiency of nutritents from 29.7% to 71.7% for nitrogen and from 34.8% to 65.6% for phosphorus. However, an excessive dose of the leachate that significantly exceeded 120 m3/d caused serious operational problems, like oil-layer formation in the grit chamber and scum layer in the primary clarifier. Thus, an supplement of food waste leachate at a dose acceptable to an existing facilities can be a practical and effective means to enhance the nutrient removal from industrial wastewater and to dispose of the food waste leachate.

Biological nutrient removal, BOD/N ratio, External carbon source, Food waste Leachate, Industrial wastewater

최유진 Yu Jin Choi , 정재운 Jae Woon Jung , 최우정 Woo Jung Choi , 윤광식 Kwang Sik Yoon , 최동호 Dong Ho Choi , 임상선 Sang Sun Lim , 정주홍 Ju Hong Jeong , 임병진 Byung Jin Lim , 장남익 Nam Ik Chang

DOI: Vol.27(No.4) 467-474, 2011

In an effort to investigate water pollution characteristics of Juam lake, water samples were collected from three sites (Sites A, B, and C) of Oenam stream which is a typical tributary of rural watershed in the lake and analyzed for N concentration and the corresponding isotope ratio (δ15N) of NO3-. Concentrations of NO3- were not dramatically different among the sites; 0.8±0.2 mg N L-1 (range: 0.0~4.3 mg N L-1) for Site A, 1.1±0.2 mg N L-1 (0.0~4.3 mg N L-1) for Site B, and 1.1±0.1 mg N L-1 (0.1~2.6 mg N L-1) for Site C. Meanwhile, δ15N tended to decrease with river flow; it was highest for Site A (45.5±5.3‰) followed by Site B (19.7±2.0‰) and Site C (8.7±1.5‰). Such high δ15N values of NO3- in Site A suggested that NO3- derived from livestock feedlot (specifically livestock excrete of which δ15N is higher than 10‰) is the predominant pollution sources despite mountainous area occupied the most of land-use in the watershed. Using the two-sources isotope mixing model, it was estimated that the contribution of cropping activities (i.e. fertilization) became greater in down-stream area (Sites B and C) due to the higher agricultural land-use than the up-stream area (Site A). Particularly, during the active cropping season, the low contribution of organic pollution sources indicated that domestic sewage was not the predominant pollution source. Therefore, it was suggested that agricultural sources such as livestock farming and cropping rather than mountainous and residential are the dominant sources of water pollution in the study area. These results could be effectively utilized in elucidating water pollution sources in rural areas and selecting water management practices.

Nitrogen isotope, Pollution source, Water quality, Watershed

김세원 Sea Won Kim , 오종민 Jong Min Oh

DOI: Vol.27(No.4) 475-485, 2011

Lake Sihwa has a very unique watershed environment, surrounded by industrial, urban and rural catchment area with different land use. The first flush phenomenon was investigated in 3 catchment area. 4TG, representing the industrial area, shows rapid discharges of highly concentrated pollutants during the early stages of a storm and it is indicating a strong first flush effect. At AS, representing the urban area, the pollutant concentration reached its peak approximately 2~3 hours after the start of storm, which is a strong first flush effect did not appear. JJB and MS represent the rural areas, the PEMC analysis results suggest that highly concentrated pollutants were discharged during the middle and latter stages of a storm, instead of early pollutant runoff due to the effects of rainwater runoff.

First flush phenomenon, Mass first flush ratio, Non-point source, Runoff

민경철 Kyung Chul Min , 김원기 Won Gee Kim , 이승목 Seung Mok Lee , 김근한 Keun Han Kim , 이희용 Hee Yong Lee , 양재규 Jae Kyu Yang , 박연종 Youn Jong Park

DOI: Vol.27(No.4) 486-490, 2011

As(V) adsorption on aluminum oxide powder which was recycled from industrial wastes containing aluminum hydroxide was evaluated. Aluminum oxide powder in this study was prepared by calcinating aluminum hydroxide wastes at 550°C. Spectroscopic analysis indicated that the aluminum hydroxide wastes were changed to aluminum oxide by calcination. Arsenic adsorption isotherm was conducted with variation of ionic strength and multiple-ion systems using Ca(II) and Cu(II). As(V) removal showed typical anionic adsorption characteristics that the removal efficiency decreased with increasing pH in single As(V) system as well as in binary and ternary system. More than 80% of As(V) at an initial concentration of 5×10-5 M was removed from aluminum oxide powder in As(V) single system. The effect of ionic strength on As(V) adsorption was negligible, which indicated the strong bonding between aluminum oxide powder and As(V). The removal efficiency of As(V) was higher in a binary system with Cu(II) than in a binary system with Ca(II).

Adsorption, Aluminum oxide, Arsenic, Multiple-ion

박혜경 Hae Kyung Park , 김화빈 Hwa Bin Kim , 이재정 Jay J. Lee , 이재안 Jae An Lee , 이혜진 Hae Jin Lee , 박종환 Jong Hwan Park , 서정관 Jung Kwan Seo , 윤석제 Seok Jea Youn , 문정숙 Jeong Suk Moon

DOI: Vol.27(No.4) 491-498, 2011

We investigated the ranges of total cellular microcystins content of cyanobacterial blooms collected in Korean lakes and rivers from 2005 to 2009. The amount and composition of microcystins of Korean cyanobacteria varied depending on the sampling water bodies and dominant cyanobacterial genera. Toxic cyanobacterial cell numbers equivalent to 1 μg MCYSTs/L using total cellular microcystin content of Korean cyanobacteria were in the range of 2,348 to 66,980,638 cells/mL. Only four samples among forty nine samples showed less cell numbers than current criterion of Harmful Algae Alert System, 5,000 cells/mL indicating current criterion do not reflect properly the microcystins content of Korean cyanobacteria. Anabaena and Aphanizomenon spp. showed three to six times higher cell numbers equivalent to 1 μg MCYSTs/L than Microcystis spp. To propose criteria of Harmful Algae Alert System for Korean toxic cyanobacteria, we calculated about 50% selective geometrical means of cyanobacterial cell numbers equivalent to 1 μg MCYSTs/L in order of toxic content. The proposed criteria for Microcystis, Oscillatoria, Anabaena, and Aphanizomenon spp., are 10,000, 20,000, 40,000, and 80,000 cells/mL, respectively.

Cyanobacterial bloom, Harmful algae alert system, Microcystins, Toxic cyanobacteria

정우혁 Woo Hyeuk Jeong , 김영일 Young Il Kim , 김홍수 Hong Su Kim , 문은호 Eun Ho Moon , 박상현 Sang Hyun Park , 이상진 Sang Jin Yi , 정상만 Sang Man Jeong , 조병욱 Byung Wook Cho , 최정호 Jeong Ho Choi

DOI: Vol.27(No.4) 499-508, 2011

We analyzed the variations of water quality with flow regime alterations to determine the characteristics of the stream where the stream management is considerably difficult due to the high variability of the flow rates. In this study, both flow rates and water qualities were monitored at the tributaries, 34 in count, of both Geum River and Sabgyo Lake Basins. The variation of water qualities were divided into 2 types, based on their stream flow rates, known as Type I and Type II. If the water quality of a stream increases during low flow rate periods compared with high flow rate periods, it is classified as Type I; if the water quality of the stream increases during high flow rate periods compared with low flow rate periods, it falls under Type II. The analysis for the variations of water qualities, of all 43 basins, resulted to 24 basins under Type I and Nineteen 19 basins under Type II. The variations of water qualities were analyzed first by using Regression Analysis followed by Statistical Analysis. The average slope of the variations of water qualities and the slope of the standard deviations were 0.00135 and 0.00477, respectively. The Probability Distributions of both Type I and Type II basins were 61.1% and 38.9%, respectively. The basin having a probability distribution of 61.1% and is also known as Type I, increases during periods of low flow rates, due to the presence of point sources. Therefore, the basin should be enforced with stream management. Before the stream management can be implemented in all streams falling under Type II, the sources of contaminants should first be estimated. These contaminants can be classified into two parts, the first is Point source pollution and the second is Non-point source pollution, where the Non-Point source pollution can be sub-divided into two types, with storm runoff and without storm runoff.

Flow duration curve, Non-point source, Water quality variation, Watershed management

조경식 Kyung Sik Cho , 이호식 Ho Sik Lee

DOI: Vol.27(No.4) 509-515, 2011

For this study the 4 sub-watersheds Okdong A, Hankang B, Jecheon A and Hankang C which are the main streams of the Han River within the mid-level region of Chungju Dam are selected and the analysis of soils has been carried out through the soil basic survey. When it comes to the soil erosion amount the soil nutrient load has been calculated by utilizing the RUSLE erosion equation. In case of the data related to the measurement of water flow and quality the information available from the "Water Information System" one of the websites run by the Ministry of Environment has been used to calculate the water pollution load. The correlation between the soil nutrient load and the water pollutant load has been analyzed through making comparison. According to the results related to the soil nutrient load of each sub-watershed the Hankang C shows the highest values TOC 29,986.92 ton/yr, TN 3,860.33 ton/yr and TP 973.97 ton/yr respectively. Even when it comes to the loads related to water quality the Hankang C shows also comparatively high values TOC 6,625.64 ton/yr, TN 7,335.01 ton/yrand TP 145.49 ton/yr respectively. The soil nutrient loads of the sub-watersheds are shown to increase towards the lower stream meaning the load increases in the order of Hankang CHankang B and Okdong A. When it comes to the water pollutant load the value goes up along down the water system meaning the load gets higher in the order of Hankang C, Hankang B and Okdong A while utilizing the mainstream within the mid-level region of Chungju Dam as the basis. The correlation study showed that the nutrient content of soil is proportional to the pollutant load in water with the strongest positive correlation with TOC.

Chungju Dam, Soil Load, Soil nutrient, Water Load

이용환 Yong Hwan Lee , 임수빈 Soo Bin Yim

DOI: Vol.27(No.4) 516-522, 2011

This study was performed to investigate the removal characteristics of phosphate by adsorption on olivine, which is generated as industrial by-products from quarry. The adsorption of phosphate on olivine was significantly achieved within 1 hour and equilibrated after 3 hours. The adsorption capacity of phosphate was enhanced with decreasing pH. The maximum adsorption capacity was observed to be 0.463 mg/g in the condition of pH 3. The Ca2+ and Mg2+ ion amount per adsorbent eluted from olivine was increased with decreasing pH. The precipitation test showed that phosphate in aqueous phase under the condition of pH 3~9 could be eliminated largely by adsorption on olivine, not precipitation. Freundlich adsorption model were successfully applied to describe the adsorption behavior of phosphate on olivine. The qm of Langmuir adsorption model were 1.3369 mg/g, 1.0544 mg/g, 1.0288 mg/g at pH 3, 6 and 9, respectively. The KF of Freundlich adsorption model were 0.4247 mg/g, 0.3399 mg/g, 0.2942 mg/g at pH 3, 6 and 9, respectively. The olivine showed high feasibility as a adsorbent for the removal of PO4-P.

Adsorption, Industrial by-product, Olivine, Phosphate

엄철용 Chul Yong Um , 주경훈 Kyoung Hoon Chu , 윤주환 Zu Whan Yun , 최익훈 Ik Hoon Choi , 박재영 Jae Young Park , 이한샘 Han Saem Lee , 고광백 Kwang Baik Ko

DOI: Vol.27(No.4) 523-532, 2011

In this study, from 2004 to 2008 influents and discharging effluents from 241 municipal public sewage treatment plants were surveyed. Statistics including average, Coefficient of Variation (CV) and Coefficient of Reliability (COR) for each season, time series analysis for removal efficiency and water quality of effluents, and a comparison of the effluent standards in Korea and other countries were presented. The average concentrations of TN and TP in influents. during winter season were 32.6 and 3.78 mg/L and during other season were 30.8 and 3.61 mg/L in 2008, respectively. The average TN concentration on the basis of the maximum monthly concentrations in the effluents during winter season ranged from 14.2~17.4 mg/L and during other season ranged from 12.2~14.8 mg/L. The TP concentration in the effluents depending on the each season was no big difference. TN removal efficiency decreased from Jan. to Feb. and TP removal efficiency decreased in Jan., Jun and July. Maximum COR during winter season were 0.61 but the COR for TN and TP during other season ranged from 0.96~1.48 and 1.09~1.81, respectively, due to big difference in the standard for TN and TP in effluents depending on the season. TN and TP standards for effluent of sewage treatment during winter season in Korea was much higher than those in other countries. Therefore the lower effluent standards during winter season is essential for the water quality improvement.

Effluent quality standards, Sewage treatment plants, Total nitrogen, TN, Total phosphorus, TP, Winter season

연인성 In Sung Yeon , 홍지영 Ji Young Hong , 문현생 Hyun Saing Mun

DOI: Vol.27(No.4) 533-541, 2011

Algal blooms have caused problems for drinking water as well as eutrophication. However it is difficult to control algal blooms by current warning manual in rainy season because the algal blooms happen in a few days. The water quality data, which have high correlations with Chlorophyll-a on Daecheongho station, were analyzed and chosen as input data of Artificial Neural Networks (ANN) for training pattern changes. ANN was applied to early forecasting of algal blooms, and ANN was assessed by forecasting errors. Water temperature, pH and Dissolved oxygen were important factors in the cross correlation analysis. Some water quality items like Total phosphorus and Total nitrogen showed similar pattern to the Chlorophyll-a changes with time lag. ANN model (No. 3), which was calibrated by water temperature, pH and DO data, showed lowest error. The combination of 1 day, 3 days, 7 days forecasting makes outputs more stable. When automatic monitoring data were used for algal bloom forecasting in Daecheong reservoir, ANN model must be trained by just input data which have high correlation with Chlorophyll-a concentration. Modular type model, which is combined with the output of each model, can be effectively used for stable forecasting.

Algal blooms, Artificial neural networks, Chlorophyll-a, Cross correlation, Daily forecasting, Parameter

이병관 Byoung Kwan Lee , 이수웅 Su Woong Lee , 김석윤 Seok Yun Kim

DOI: Vol.27(No.4) 542-550, 2011

Changes of suspended sediment concentration in the Seomjin river estuary located in south sea of the Korea peninsula were investigated during the spring tide in autumn (i.e. 25 hours in October) 2000 and winter (i.e. 25 hours in February) 2001. The changes of temperature and salinity during the spring tide in October 2000 showed larger variations than the those in February 2001. During the spring tide in October 2000, currents at bottom layer were observed to be stronger than during the spring tide in February 2001, showing that both of the two periods had ebb currents-predominant tide asymmetries. The suspended sediment concentrations in October 2000 were larger than the those in February 2001. At the time of the maximum of tide currents or after about one hour of the maximum during the autumn months, the suspended sediment turbidity was observed to be maximum. Another observation station at Hadong upstream from the Seomjin river estuary showed about one hour delay in tide phase, Thereby, the suspended sediment concentration showed high turbidity after two hours at bottom and three hours at surface layer, in particular, in October 2000. This results can be explained by the facts that river discharge increased significantly after the summer rainy season, causing also increase of erosion processes by strong current velocity at bottom layer.

Fall and winter months, Hadong, Seomjin river, Spring tide, Suspended sediment