최진용 Choi Jin Yong , 홍은미 Hong Eun Mi , 남원호 Nam Won Ho , 김학관 Kim Hak Kwan

DOI: JKWST Vol.51(No.6) 1-9, 2009

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Watershed topographical data is essential for the management for water resources and watershed management in terms of hydrology analysis. Collecting watershed topographical and meteorological data is the first step for simulating hydrological models and calculating hydrological components. This study describes a specialized Web-based Geographic Information Systems, Soil Water Assessment Tool model data generation system, which was developed to support SWAT model operation using Web-GIS capability for map browsing, online watershed delineation and topographical and meteorological data extraction. This system tested its operability extracting watershed topographical and meteorological data in real time and the extracted spatial and weather data were seamlessly imported to ArcSWAT system demonstrating its usability. The Web-GIS would be useful to users who are willing to operate SWAT models for the various watershed management purposes in terms of spatial and weather preparing.

이진원 Lee Jinwon , 김남원 Kim Namwon , 이정우 Lee Jeongwoo , 서병하 Seo Byungha

DOI: JKWST Vol.51(No.6) 11-16, 2009

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This study is to suggest the SWAT model as inputs for the estimation of CN (Curve number) if we do not have hourly rainfall and runoff data in the ungaged watershed. The daily CNs were estimated by using SWAT model for Chungju dam watershed and the CNs by hourly rainfall and runoff data in the same period with daily CN estimation were also estimated. Then the daily and hourly CNs were compared each other. The CNs by SWAT model were larger than the actual CNs. 7.4% larger in AMC-I, 1.2% in AMC-II, and 6.3% in AMC-III respectively. If we consider various uncertainties in the estimation of CN, the error of 6.8% could be acceptable for the application in the field.

김학관 Kim Hak Kwan , 이은정 Lee Eun Jeong , 박승우 Park Seung Woo , 강문성 Kang Moon Seong

DOI: JKWST Vol.51(No.6) 17-23, 2009

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The Soil and Water Assessment Tool (SWAT) model was used in this study to evaluate the hydrologic impacts by the impervious surface change in the farm region. The model was calibrated and validated by using four years (1999-2002) of measured data for the Gyeongancheon watershed in Korea. The simulation results agreed well with observed values during the calibration and validation periods. Land use scenarios including various changes of the plastic film house area in the farm region were applied to assess their effects on watershed hydrology. The results indicated that the surface direct (5.6%~14.0%) and total runoff (0.8%~1.5%) increased, but the groundwater discharge (10.7% ~ 27.7%) and evapotranspiration (1.5%~3.3%) decreased as the plastic film house area (5.7%~12.4%) increased.

정재운 Jung Jae Woon , 윤광식 Yoon Kwang Sik , 주석훈 Joo Seuk Hun , 최우영 Choi Woo Young , 이용운 Lee Yong Woon , 류덕희 Rhew Doug Hee , 이수웅 Lee Su Woong , 장남익 Chang Nam Ik

DOI: JKWST Vol.51(No.6) 25-31, 2009

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In this study, pollutant loads delivery ratio by flow duration in Hwangryoung A watershed was estimated. The delivery ratio was estimated with measured data by Ministry of Environment(MOE) and the regression equation based on geomorphic parameters. Eight day interval flow data measured by the MOE were converted to daily flow to calculate daily load and flow duration curve by correlating data of neighboring station which has daily flow data. Regression equation developed by previous study was tested to study watershed and found to be satisfactory. The delivery ratios estimated by two methods were compared. For the case of Biochemical oxygen demand(BOD), the delivery ratios of low flow condition were 7.6 and 15.5% by measured and regression equation, respectively. Also, the delivery ratios of Total phosphorus(T-P) for normal flow condition were 13.3 and 6.3% by measured and regression equation, respectively.

김미현 Kim Mi Hyun , 이달원 Lee Dal Won

DOI: JKWST Vol.51(No.6) 33-43, 2009

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This study analyzed data on the pore water pressure, the ground water level, the horizontal displacement and the resistivity monitoring from instrument system, which is established to evaluate the safety in reservoirs. The pore water pressure in the embankment ranged from 0.035～1.116kg/㎠. The seepage that piping showed, as well as the leakage from the reservoirs are acceptable for the safety management of the reservoir. The maximum horizontal displacement and direction analyzed from the measured inclinometer data gives us very effective information to evaluate the safety in reservoirs. The resistivity monitoring technique, which is obtained on the reservoir crest, is an efficient tool to detect leakage zone. The safety index (SI) was predicted by the resistivity monitoring, and was evaluated to have a safety level of 0.8-1.0 at all reservoirs. Safety evaluations of reservoir through instrument systems are effective when studying the embankment, when the results of the instrument system have been analyzed compositively.

서원명 Suh Won Myung , 배용한 Bae Yong Han , 허해준 Heo Hae Jun , 곽철순 Kwak Cheul Soon , 이석건 Lee Suk Gun , 이종원 Lee Jong Won , 윤용철 Yoon Yong Cheol

DOI: JKWST Vol.51(No.6) 45-52, 2009

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This study was conducted in the process that the basic plan of the formation of the thermal energy complex in the Iwon reclaimed land of Taean was being made. Targeting for the large-sized greenhouse to be made in this area, it examined the cooling and heating load and the amount of ventilation, and also analyzed the economic efficiency of heating. The research results are as per the below: The minimum ambient temperature of this area was measured on January 7, 2001, which was -18.7 ℃, and the maximum ambient temperature of this area was measured on July 24, 1994, which was 36.7 ℃. The maximum heating load was 39,011 MJ/h, but the date when the maximum heating load was not consistent with the date when the minimum temperature was measured. The maximum cooling load was 88,562MJ/h, It was approximately 2.3 times of the maximum heating load, which was measured at 14:00 hours on September 4, 2000. The maximum amount of ventilation heat was 138,639MJ/h. Assuming the rate of solar heat use as 10 %, 20 %, 50 %, and 100 %, the total sum of cost-benefit would be ￦-193,450,000, ￦-634,930,000, ￦-3,372,960,000, and ￦-9,850,420,000, respectively 20 years later. The break-even point of the geothermal heat pump would be about 4 years for 10 % use, about 3 years for 20 % or 50% use, and approximately 6 years for 100% use. It was found that 50 % use would be most advantageous. In case two systems are combined, the break-even point will be 10 years, 8 years, and 11 years respectively.

정희영 Jeong Hee Young , 류인구 Ryu In Gu , 정세웅 Chung Se Woong

DOI: JKWST Vol.51(No.6) 53-62, 2009

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The EFDC (Environmental Fluid Dynamics Code), a numerical model for simulating three-dimensional (3D) flow, transport, and biogeochemical processes in surface water systems including rivers, reservoirs, and estuaries, was applied to assess the effect of sea water and fresh water exchange rates (Q_e) on the mixing characteristics of a conservative pollutant (tracer) induced from upstreams and salinity in Saemangeum Lake, Korea. The lake has been closed by a 33 km estuary embankment since last April of 2006, and now seawater enters the lake partially through two sluice gates (Sinsi and Garyuk), which is driving the changes of hydrodynamic and water quality properties of the lake. The EFDC was constructed and calibrated with surveyed bathymetry data and field data including water level, temperature, and salinity in 2008. The model showed good agreement with the field data and adequately replicated the spatial and temporal variations of the variables. The validated model was applied to simulated the tracer and salinity with two different gate operation scenarios: RUN-1 and RUN-2. RUN-1 is the case of real operation condition (Q_e=25,000,000 ㎥) of 2008, while RUN-2 assumed full open of Sinsi gate to increase Q_e by 120,000,000 ㎥. Statistical analysis of the simulation results indicate that mixing characteristics of pollutants from upstream can be significantly affected by the amount of Q_e.

김해도 Kim Hae Do , 김선주 Kim Sun Joo , 이광야 Lee Kwang Ya

DOI: JKWST Vol.51(No.6) 63-68, 2009

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Most of agricultural reservoirs in Korea have no function of flood control except 5% of reservoirs even exposed to natural disaster. In addition, there are increasing needs for the reservoir to guarantee the release of environmental flow to the downstream. Thus, the purpose of this paper is to study the priority decision method for the reservoir redevelopment satisfying both water utilization and flood control. The major scopes of this research are to set up six priority indices and to make needed GIS data for calculating each priority. There is important consideration of obtaining the data or not in deciding the indices. Although the detailed indices is expected to better reflect redevelopment priority but the subjective indices like, ‘opinion’ and ‘landscape’ are excluded. From the results, it will enables the six priority indices to really assist in decision redevelopment priority of agricultural reservoirs.

봉태호 Bong Tae-ho , 손영환 Son Young-hwan , 김성필 Kim Seong-pil , 허준 Heo Jun , 장병욱 Chang Pyoung-wuck

DOI: JKWST Vol.51(No.6) 69-76, 2009

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Soils exhibit creep behavior in which deformation and movement proceed under a state of constant stress or load. In Korea, weathered soil is abundant and occupies around one-third of the country. Weathered soil is visually described as a sandy or gravelley soil, but the behavior is quite different from the behavior of usual sand and gravel. In particular, the permeability of weathered soil is similar to sand, but the durability of settlement is similar to clay. Therefore analysis of time-dependent behavior of weathered soil is very important. In this study, Creep tests with weathered soils were carried out under constant principal stress differences of various stress levels which were experimentally obtained by triaxial compression test. The results of these tests showed the creep behavior for which the deformation increased with time, and the results are consistent with phenomenological model by creep equation of Singh-Mitchell.

김완영 Kim Wan Young

DOI: JKWST Vol.51(No.6) 77-81, 2009

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This study was performed to evaluate applicability of patching materials for underwater dam concrete structure. Two kinds of patching materials was investigated. Laboratory experimentals were conducted by workability, compressive strength, bond strength, chloride ion penetration, abrasion resistance. Test results showed that the most performances are relatively good except chloride ion penetration.

남효석 Nam Hyo Seok , 이상호 Lee Sang Ho , 권무남 Kwon Moo Nam

DOI: JKWST Vol.51(No.6) 83-90, 2009

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This study was carried out to evaluate the vertical stress properties in sandy soil according to changes of loading type in soil bin compacted three layers. The following conclusions and comparisons have been made based on careful analysis from theoretical and experimental methods. : When sandy soil subjected to cycle-loading, compression of foundation and diffusion of vertical stress increment(Δσ_z) were influenced by magnitude of loading plate. When sandy soil subjected to reloading after removing of pre-loading, the distribution of Δσ_z depth at one time of loading plate width was different from its distribution at more deep point cause of load hysteresis, so in case of design of structure, the effect of Δσ_z as depth must be considered. The increment of vertical stress will be different as loading condition and foundation depth, the loading condition must be considered in case of structure design.

홍민 Hong Min , 최경숙 Choi Kyung-sook

DOI: JKWST Vol.51(No.6) 91-96, 2009

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This study describes a zero discharge and reuse system developed for rural areas. The purpose of the system is decontamination of used irrigation water for down-stream usage and reuse of wastewater in rural villages for preventing water shortage problem expected to happen in near future. The system consists of anoxic, FES (Ferrous Electricity System), Oxic, Cralifier processes. The main feature of the system is to remove phosphorous by using Fe-ionizing module. Indoor experiments were undertaken with a trial product of the system to test its performance. The removal capacities of T-P, T-N, and BOD were examined. Also the proper time for the replacement of iron plate module was tested as well as the efficiency of T-P removal rate based on the usage of an automatic washing system for the iron plate. As results, the system showed very good water purification performances through obtaining the results of over 90 % removal rates from T-P, BOD, and 67 % from T-N. The proper time period for replacement of iron plate was maximum 2 years, and also efficiency of T-P removal rate found to be greatly influenced by the usage of an automatic washing system from the test.

김영익 Kim Young Ik , 성찬용 Sung Chan Yong

DOI: JKWST Vol.51(No.6) 97-103, 2009

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This study was performed to evaluate the strength and durability properties of recycled polymer concrete using unsaturated polyester resin and recycled aggregates. Unsaturated polyester resin, natural and recycled aggregates and fly ash were used. The mix proportions were determined to satisfy the requirement for the workability and slump according to aggregate sizes (5-10 and 5-25 mm) and unit binder contents (10 % and 12 %). Tests for the compressive and flexural strength, freezing and thawing and durability for 20 % sulfuric solution were performed. The compressive and flexural strength of recycled polymer concrete were in the range of 85~97 MPa and 17.9~20.8 MPa, respectively. The strengths of recycled polymer concrete using recycled aggregate have similar or slightly decreased compared to polymer concrete using natural aggregate. After 300 cycles of freezing and thawing, weight decrease ratio and durability factor of recycled polymer concrete were in the range of 0.13~1.42 % and 94~99, respectively.

황진용 Hwang Jin Yong , 연규석 Yeon Kyu-seok , 김익재 Kim Ik Jae , 김기성 Kim Ki-sung , 최중대 Choi Joongdae , 전지홍 Jeon Ji Hong , 임경재 Lim Kyoung Jae

DOI: JKWST Vol.51(No.6) 150-159, 2009

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With urbanization in many countries, many pervious areas are being converted into impervious areas. These land use changes cause many negative impacts on runoff and water quality in the areas. Especially runoff volume and peak runoff are increasing with urbanization. In addition to the increased runoff, more pollutant transports to the downstream areas. For these reasons, Low Impact Development (LID) are nowadays being introduced in urban planning. For environment-friendly and economical urban development, the LID Integrated Management Practices (IMPs) are applied in various urban development. However, exact effects on runoff and water quality of various LID IMPs are not assessed with proper LID evaluation technique. Thus, the SWMM (Storm Water Management Model) 5.0 model was slightly modified to simulate the effect of infiltration manhole on runoff and water quality. For comparison of runoff and TSS (Total Suspended Solids) from the study area (26.5 ha), three scenarios were made in this study. It was found that runoff volume, peak runoff, and TSS could be reduced with infiltration manholes and pervious pavements to some degree. Although, there are many limitations in the analysis of LID effects on runoff and TSS, similar trends shown in this study would be expected with site-specific LID IMPs. Thus, it is strongly recommended that various site-specific LID IMPs, such as infiltration facilities, should be applied as much as possible for environment-friendly urban planning.