우재열 Woo Jae Yeoul , 김진수 Kim Jin Soo

DOI: JKWST Vol.52(No.6) 1-7, 2010

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This study was carried out to investigate the effect of hydro power factors (e.g., irrigation area, watershed area, active storage, gross head) on annual generation capacity and operation ratio for agricultural reservoirs in Chungbuk Province with active storage of over 1 million m³. The annual generation capacity and operation ratio were estimated using HOMWRS (Hydrological Operation Model for Water Resources System) from last 10-year daily hydrological data. The correlation coefficients between annual generation capacity and the hydro power factors except gross head were high (over 0.87), but the correlation coefficients between operational rate and the factors were low (below 0.28). The optimum multiple regression equations of the annual generation capacity were expressed as the functions of watershed area, active storage, and gross head. Also, the simple regression equation of annual generation capacity was expressed as a function of watershed area. The average relative root-mean-square-error (RRMSE) between observed and estimated values by the optimum multiple regression equations was smaller than that by the simple regression equation, suggesting that the former has more accuracy than the latter

김대식 Kim Dae Sik , 김진택 Kim Jin Taek , 표기형 Pyo Ki Hyong , 이진범 Lee Jin Bum

DOI: JKWST Vol.52(No.6) 9-17, 2010

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In this paper, an automatic cruise system of unmanned boat was developed for surveying water depth in reservoir using GIS (geographic information system)-GPS (global positioning system) Technologies. the automatic cruise system consisted of an automatic path generation program (APGP) and an automatic boat control program (ABCP). A grid processing method with 3×3 roving window in GIS function was used to develop the APGP. For development of the ABCP, GPS and its coordinate calculation technique were introduced. The developed system was tested to verify the applicability for a sample reservoir, Misan reservoir located on Ansan city of Kyunggi province. From the test results, this study found the APGP generated cruise path automatically according to input condition on grid size of 5 m, 10 m, and 20 m, as well as, the ABCP also tracked well the cruise paths with high position accuracy. Another verification result on surveying time for 20 ha of water area also showed that the new system could survey water depth of reservoir quickly, including very high quality of spatial resolution.

임병란 Lim Byung-ran , 주티담롱판 Jutidamrongphan Warangkana , 박기영 Park Ki Young

DOI: JKWST Vol.52(No.6) 19-26, 2010

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Batch experiments were conducted to investigate growth and nutrient removal performance of microalgae Chlorella vulgaris by using piggery wastewater in different concentration of pollutants and the common growth models (logistic, Gompertz and Richards) were applied to compare microalgal growth parameters. Removal of nitrogen (N) and phosphorus (P) by Chlorella vulgaris showed correlation with biomass increase, implying nutrient uptake coupled with microalgae growth. The higher the levels of suspended solids (SS), COD and ammonia nitrogen were in the wastewater, the worse growth of Chlorella vulgaris was observed, showing the occurrence of growth inhibition in higher concentration of those pollutants. The growth parameters were estimated by non-linear regression of three growth curves for comparative analyses. Determination of growth parameters were more accurate with population as a variable than the logarithm of population in terms of R square. Richards model represented better fit comparing with logistic and Gompertz model. However, Richards model showed some complexity and sensitivity in calculation. In the cases tested, both logistic and Gompertz equation were proper to describe the growth of microalgae on piggery wastewater as well as easy to application.

박근애 Park Geun Ae , 박종윤 Park Jong Yoon , 신형진 Shin Hyung Jin , 박민지 Park Min Ji , 김성준 Kim Seong Joon

DOI: JKWST Vol.52(No.6) 27-37, 2010

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The effect of potential future climate change on the storage rate of paddy field during storm periods (June - September) was assessed using the daily paddy water balance model. The CCCma CGCM2 data by SRES (special report on emissions scenarios) A2 and B2 scenarios of the IPCC (intergovernmental panel on climate change) was used to assess the future potential climate change. The future weather data for the year 2020s, 2050s and 2080s was downscaled by Change Factor method through bias-correction using 30 years weather data. The future (2020s, 2050s and 2080s) rainfall, storage and irrigation of paddy field, runoff in paddy levee and ponding depth were analyzed for the A2 and B2 climate change scenarios based on a base year (2005). The future irrigation change of paddy field was projected to increase by decrease in rainfall. So, runoff change in paddy levee was decrease slightly, future storage change of paddy was projected to increase.

전지홍 Jeon Ji Hong

DOI: JKWST Vol.52(No.6) 39-48, 2010

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Sediment yields from Imha watershed were simulated during 1993-2008 using Hydrologic Simulation Program-Fortran (HSPF). Using observed daily stream flow for 2004-2008 and hourly suspended solid concentration for three events during 2006, HSPF was calibrated and validated at the sites of Imha and Youngyang for stream flow and Dongchun and Jangpachun for sediment yield. The calibration and validation results represented high model efficiency for simulating daily stream flow and hourly suspended solid. The determination coefficients of calibration and validation were 0.90 and 0.81 for daily stream flow, and 0.91 and 0.86 for monthly stream flow, respectively. Based on model tolerances for calibration and validation of stream flow, HSPF performance for simulating stream flow represented ‘very good’. The determination coefficients of calibration and validation were 0.94-0.96 and 0.95 for hourly sediment yields, respectively. The average yearly sediment yield during 1993-2008 was 122,290 ton/year and most of sediment yield (77 % of total yield) were generated from June to August. The calibrated HSPF simulated well the movement of water and eroded soil within Imha watershed.

김종옥 Kim Jong Ok , 박찬기 Park Chan Gi , 차상선 Cha Sang Sun

DOI: JKWST Vol.52(No.6) 49-56, 2010

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This study was conducted to find out the best optimum design method for the design of reinforced concrete agricultural aqueduct abutment and pier structures. The mixed-discrete optimization and continuous optimization method were applied to the design of reinforced concrete agricultural aqueduct abutment and pier and the results of these optimization methods were compared each other. It is proved that mixed-discrete optimization method is more reliable, efficient and reasonable than continuous optimization method for the optimum design of the reinforced concrete agricultural aqueduct abutment and pier.

신유리 Shin Yu-ri , 윤춘경 Yoon Chun Gyeong , 손영권 Son Yeong Kwon , 김형중 Kim Hyung Joong

DOI: JKWST Vol.52(No.6) 57-62, 2010

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박종윤 Park Jong-yoon , 조형경 Joh Hyung-kyung , 정인균 Jung In-kyun , 정관수 Jung Kwan-soo , 이주헌 Lee Joo-heon , 강부식 Kang Bu-sik , 윤창진 Yoon Chang-jin , 김성준 Kim Seong-joon

DOI: JKWST Vol.52(No.6) 63-73, 2010

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This study is to develop a downstream flood damage prediction model for efficient confrontation in case of extreme and flash flood by future probable small agricultural dam break situation. For a Changri reservoir (0.419 million m³) located in Yongin city of Gyeonggi province, a dam break scenario was prepared. With the probable maximum flood (PMF) condition calculated from the probable maximum precipitation (PMP), the flood condition by dam break was generated by using the HEC-HMS (Hydrologic Engineering Center - Hydrologic Modeling System) model. The flood propagation to the 1.12 km section of Hwagok downstream was simulated using HEC-RAS (Hydrologic Engineering Center - River Analysis System) model. The flood damaged areas were generated by overtopping from the levees and the boundaries were extracted for flood damage prediction, and the degree of flood damage was evaluated using IDEM (Inundation Damage Estimation Method) by modifying MD-FDA (Multi-Dimensional Flood Damage Analysis) and regression analysis simple method. The result of flood analysis by dam-break was predicted to occurred flood depth of 0.4m in interior floodplain by overtopping under PMF scenario, and maximum flood depth was predicted up to 1.1 m. Moreover, for the downstream of the Changri reservoir, the total amount of the maximum flood damage by dam-break was calculated nearly 1.2 billion won by IDEM.

김필식 Kim Phil Sik , 김선주 Kim Sun Joo , 심재훈 Shim Jae Hoon

DOI: JKWST Vol.52(No.6) 75-83, 2010

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The objective of this paper is to study the discharge characteristics of pollutant loads in small watershed according to probability rainfall using the Hydrologic Simulation Program-Fortran (WinHSPF). The subwatershed of Gosam reservoir watershed in Gyeonggido province was simulated and the probability rainfall of study area was estimated by recurrence interval and duration. The probability rainfalls are 156.5, 205.9 and 277.4 mm for 6 hrs, 12 hrs and 24 hrs in 10 year frequency, and each probability rainfalls is distributed by Huff's 4th quantiles method and applied to HSPF. The pollutant loads were high for initial rainfall. The concentrations of TN, TP and BOD were high as rainfall duration is shorter and rainfall intensity is higher.

김성재 Kim Sung Jae , 박태양 Park Tae Yang , 장민원 Jang Min Won , 김상민 Kim Sang Min

DOI: JKWST Vol.52(No.6) 85-94, 2010

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The objective of this study is to estimate the flood runoff for three guaged stations within Namgang-Dam watershed which are operated by KWATER. For a flood runoff simulation, HEC-HMS was applied and the simulated runoff was compared with observed from 2004 to 2008. The watershed area of Sancheong, Shinan, and Changchon were 693.6 km², 413.4 km², and 346.48 km², respectively. The average runoff ratio of observed runoff for three watersheds were 0.725, 0.418, and 0.586, respectively. The dominant land cover of three watersheds are forest with the value of 71.6 %, 73.1 %, and 82.0 %. Three different cases according to the potential maximum retention of forest areas for calculating the curve number were applied to decrease the error between the simulated and observed. The simulated peak runoff of case 3 which applied the 90 % of potential maximum retention of curve number which is equivalent to AMCⅠ for all the AMCⅠ, AMCⅡ, and AMCⅢ conditions showed least root mean square error (RMSE). The case 1, which was suggested by previous study, showed high discrepancy between the simulated and observed. Since the forest area consists of more than 70 % for all three watersheds, the application of curve number for forest is critical to improve the estimation errors. Further research is required to estimate the more accurate curve number for forest area.

신현준 Shin Hyun Jun , 원철희 Won Chul Hee , 최용훈 Choi Yong Hun , 김태유 Kim Tae Yoo , 최중대 Choi Jung Dae

DOI: JKWST Vol.52(No.6) 95-100, 2010

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Researchers developed Sediment Trap Drain Channel (STDC) as a solution of the reduction of soil erosion and muddy runoff from a alpine field. The STDC is the one that can take a role of grit chamber by installing the shield made of woods in the concrete channel. The study was conducted 8 kinds of stages according to the amount of soil loss and the inflow. Evaluation factors were ss concentration, turbidity and reduced soil. The results of study showed lessness of ss concentration and turbidity from the lower spot than the upper spot. The average reduction rate of ss concentration was 74 % and the average reduction rate of turbidity was 62 %. It was turned out that the performance related soil loss and muddy runoff of the STDC is effective. The governance was needed to expect the effectiveness of the STDC.

성찬용 Sung Chan Yong , 김영익 Kim Young Ik

DOI: JKWST Vol.52(No.6) 101-110, 2010

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This study was performed to evaluate the void ratio and strength of porous polymer concrete used coarse aggregates and unsaturated polyester resin to find optimum mix design of porous polymer concrete for planting block. Also, this study was performed to evaluate the planting properties of herbaceous plant and cool-season grass in porous polymer blocks based on the experimental results of porous polymer concrete to develop environmentally friendly planting blocks. Tests for the void ratio and compressive strength of porous polymer concrete were performed at the curing age 7 days. Also, kinds of plants such as Tall fescue, Perennial ryegrass, Lespedeza and Alfalfa for planting were applied to porous polymer blocks. Within 6 weeks after seed, initial germination ratio, cover view and growth length for planting blocks were estimated by various methods.

이달원 Lee Dal Won , 임진혁 Lim Jin Hyuk

DOI: JKWST Vol.52(No.6) 111-123, 2010

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In this study, laboratory model test on utilization of recycled aggregates and crushed stone as horizontal drains to use alternative material of sand in soft ground is practiced. The coefficient of permeability of the recycled aggregates and crushed stone showed largely 1.2～5.1 times and 2.0～3.3 times greater than sand, respectively. The horizontal coefficient of permeability in case of installing the horizontal perforated drain pipe showed largely 1.9～6.8 times more than the case of not installing. The drainage distance showed 1.7～1.8 times greater than sand. When a degree of consolidation is 90 %, there is no delay of consolidation in SCP and PVD improvement sections. Therefore, it is proven that the field applicability is excellent. Also, the suitable quality management criterion is presented to make use of a horizontal drains in soft ground on the basis of analysis of the physical and environmental characteristics.

성찬용 Sung Chan Yong , 김영익 Kim Young Ik

DOI: JKWST Vol.52(No.6) 125-134, 2010

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This study was performed to evaluate the workability, strengths and durability of polymer concrete using oyster shell that are reclaimed at public shore illegally or leaved on the surroundings of shore to prevent the environmental pollution. We investigated the effect of oyster shell powder (OSP) and CaCO₃. on the slump, compressive strength, flexural strength, acid sulfuric and freezing and thawing resistance as a filler of polymer concrete. Modified OSP obtained by crushing oyster shell (less than 0.15 mm size) consists of 60.47 wt% of SiO₂ and 39.5 wt% of CaCO₃. As a result of slump test by OSP and CaCO₃. contents, it is found that slump of specimen used OSP is lower than that used CaCO₃. and the more OSP contents are, its slump is increased. Compressive and flexural strength of polymer concrete using OSP are similar or slightly lower than that using CaCO₃. In acid sulfuric test for 5 % H₂SO₄ and freezing thawing test, regardless of kinds of fillers and contents are not found fatal defects in weight change, falling-off in surface and durability factor.

문종필 Moon Jong Pil , 김태철 Kim Tai Cheol , 이성현 Lee Sung Hyoun , 권진경 Kwon Jin Kyung , 이수장 Lee Su Jang , 임경재 Lim Kyoung Jae

DOI: JKWST Vol.52(No.6) 135-144, 2010

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This study was performed to suggest a soil loss reduction skill through estimating soil erosion from a small watershed including each type of sloping agriland by using GEOWEPP model. Experimental watershed at Gangwon province was selected for very typical sloping fields of highland agriculture in Alpine area. Runoff discharge and sediment load, hourly rainfall amount occurred during storm event were gauged, and weather data were obtained from Daegwallyeong meteorological station. The results of GEOWEPP model estimation showed that relative error values for total runoff discharge and sediment load were 3 %, -14.5 % respectively. Based on the result, soil erosion and waterway path map for each hillslope were made to select target hillslope. Several hillslopes of severe soil erosion were analyezed and then the optimal vegetative filter strip construction width and waterway path to plant grass were decided by using GEOWEPP Model.