김선주 Kim Sun Joo , 김필식 Kim Phil Shik , 지용근 Jee Yong Keun

DOI: JKWST Vol.51(No.4) 1-6, 2009

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This study analyzed and evaluated the effect of agricultural water reduction by introducing automated agricultural water management using alternative cost approach. The approach is possible to evaluate none market property as an asset. The saved agricultural water was evaluated as none market property. As the alternative goods, Seongju and Donghwa dam, typical irrigation dams in domestic, were employed. The economic benefit from water saving effect of an automated agricultural water management was calculated as depreciation expense and maintaining cost of construction agricultural dam per saved agriculture water. As a result, the saved agriculture water was 8.5 million ton per year, and the economic benefit of it was 1.3~2.1 million won.

정상옥 Chung Sang-ok

DOI: JKWST Vol.51(No.4) 7-13, 2009

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The paddy irrigation demand for Nakdong river basin in Korea due to the climate change have been analyzed using regional climate model outputs. High-resolution (27 × 27 km) climate data for SRES A2 scenario produced by the Meteorological Research Institute (METRI), South Korea, and the observed baseline climatology dataset (1971-2000) were used. The outputs from the ECHO-G GCM model were dynamically downscaled using the MM5 regional model by METRI. Maps showing the predicted spatial variations of changes in climate parameters and paddy irrigation requirements have been produced using the geographic information system. The results of this study showed that the average growing season temperature will increase steadily by 1.5 °C (2020s A2), 3.2 °C (2050s A2) and 5.2 °C (2080s A2) from the baseline (1971-2000) 19.8 °C. The average growing season rainfall will change by -3.4 % (2020s A2), 0.0 % (2050s A2) and +16.5 % (2080s A2) from the baseline value 886 mm. Assuming paddy area and cropping pattern remain unchanged the average volumetric irrigation demands were predicted to increase by 5.3 % (2020s A2), 8.1 % (2050s A2) and 2.2 % (2080s A2) from the baseline value 1.159 × 10⁶ ㎥. These projections are different from the previous study by Chung (2009) which used a different GCM and downscaling method and projected decreasing irrigation demands. This indicates that one should be careful in interpreting the results of similar studies.

김상민 Kim Sang Min , 성충현 Seong Choung Hyun , 박승우 Park Seung Woo

DOI: JKWST Vol.51(No.4) 15-20, 2009

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The purpose of this study was to test the applicability of the HSPEXP model performance criteria for calibrating hydrologic parameters of HSPF. Baran watershed, located at Whasung city, was selected as a study watershed in this study. Input data for the HSPF model were obtained from the digital elevation map, landuse map, soil map and others. Water flow data from 1996 to 2000 was used for calibration and from 2002 to 2007 was for validation. Using the HSPEXP decision-support software, hydrology parameters were adjusted based on total volume, then low flows, storm flows, and finally seasonal flows. Suggested criteria for each model performance variables were referenced from the previous research. For the calibration period, all the HSPEXP model performance criteria were satisfied while two criteria were slightly violated for the validation period.

윤준노 Youn Joon No , 성찬용 Sung Chan Yong , 김영익 Kim Young Ik

DOI: JKWST Vol.51(No.4) 21-27, 2009

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This study was performed to evaluate the physical and mechanical properties of porous concrete using waste activated carbon. Material used were ordinary portland cement, recycled coarse aggregate, waste activated carbon and superplasticizer. The replacement ratios of waste activated carbon were 0,1,2,3,4,5,6,7,8,9 and 10%. The void ratio was decreased and ultrasonic pulse velocity was increased with increasing the waste activated carbon powder, respectively. The compressive strength and flexural strength of porous concrete using waste activated carbon powder were in the range of 8.21∼16.58 MPa and 1.69∼3.68 MPa, respectively. The pH degree of porous concrete in 1day and 77days were shown in 12.50∼12.63 and 10.21∼10.70, respectively. Accordingly, waste activated carbon can be used for porous concrete material.

곽계환 Kwak Kae Hwan , 장화섭 Jang Hwa Sup , 양동운 Yang Dong Woon , 김호선 Kim Ho Sun

DOI: JKWST Vol.51(No.4) 29-36, 2009

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This is a basic experimental study to apply FRP modular box member to a variety of construction structures exposed to flexural strength, such as a slab and a girder. Applying FRP modular box member to a real structure requires a large section. FRP box member was made into modular systems. Tests were conducted under various conditions in order to analyze jointing performance of the developed FRP modular box member as a large section. For the methods of jointing FRP modular box member, synthetic resins connection, mechanical connection, and a combination of both were used to test both length and breadth connection. As a result of the test, using urethane + two bolts + sheets was the most efficient method of connecting FRP modular box member. It is expected that the proposed joint system in this study will contribute to the increase of failure load and synthesis behavior of FRP modular box member.

나상일 Na Sang Il , 박종화 Park Jong Hwa

DOI: JKWST Vol.51(No.4) 37-42, 2009

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This study extracted Near Infrared (NIR) band using Image Processing Technology (IPT), and calculated Normalized Difference Vegetation Index (NDVI). Aerial photography from Daum portal in combination with high resolution satellite image was employed to improve vegetation sensitivity by extracting NIR band and calculating NDVI with comparison to QuickBird result. The extracted NIR band and NDVI through IPT presented similar distribution pattern. In addition, a regression analysis by land cover character showed high correlation paddy and forest. Therefore, this approach could be acceptable to acquire vegetation environment information.

손재권 Son Jae Gwon , 최진규 Choi Jin Kyu , 조재영 Cho Jae Young

DOI: JKWST Vol.51(No.4) 43-47, 2009

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Soil aggregation is an important part of influencing the soil behaviors in reducing rainfall-runoff and soil erosion, aeration, infiltration, and root penetration. Some inorganic materials such as clay minerals, Fe and Al oxides/hydroxides, and calcium carbonate can act as cementing agents within macroaggregates. The objective of this study was to determine the effects of different cementing agents (Fe, Mn, and Al) on soil aggregate formation in reclaimed tidelands. Water stable aggregate ratio and MWD (mean weight diameter) were higher in iron dioxides treatment than two other treatments. This result indicates significant correlation between soil aggregate formation and iron dioxides.

맹승진 Maeng Seung-jin , 김병준 Kim Byeoung-jun , 김형산 Kim Hyung-san

DOI: JKWST Vol.51(No.4) 49-55, 2009

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This paper is to induce design floods through L-moment with 3 and 4 parameter Kappa distributions including test of independence by Wald-Wolfowitz, homogeneity by Mann-Whitney and outlier by Grubbs-Beck on annual maximum flood flows at 9 water level gaging stations in Han, Nakdong and Geum Rivers of South Korea. After analyzing appropriateness of the data of annual maximum flood flows by Kolmogorov-Smirnov test, 3 and 4 Kappa distributions were applied and the appropriateness was judged. The parameters of 3 and 4 Kappa distributions were estimated by L-moment method and the design floods by water level gaging station was calculated. Through the comparative analysis using the relative root mean square errors (RRMSE) and relative absolute errors (RAE) calculated by 3 and 4 parameter Kappa distributions with 4 plotting position formulas, the result showed that the design floods by 4 parameter Kappa distribution with Weibull and Cunnane plotting position formulas are closer to the observed data than those obtained by 3 parameter Kappa distribution with 4 plotting position formulas and 4 parameter Kappa distribution with Hazen and Gringorten plotting position formulas.

김필식 Kim Phil Shik , 김선주 Kim Sun Joo , 이재혁 Lee Jae Hyouk , 지용근 Jee Yong Keun

DOI: JKWST Vol.51(No.4) 57-66, 2009

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손재권 Son Jae Gwon , 최진규 Choi Jin Kyu , 조재영 Cho Jae Young

DOI: JKWST Vol.51(No.4) 67-73, 2009

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Chemical properties of soil in the proposed horticultural complexes of Saemangeun reclaimed tideland were studied for sustainable development of the newly reclaimed land resources. The soil texture of Gwanghwal, Gyehwa, Mangyeong and Okgu complex area were sandy loam. The pH and ESP (exchangeable sodium percentage) were 7.42 to 7.82 and 61.05 to 73.62 %, respectively. Compared to general agricultural land in Korea, the soil organic matter and other plant nutrients were low. The concentrations of heavy metals in the soil were found to be acceptable except several sites where they doesn't meet the warning standard of agricultural land contamination. Continuous monitoring and interception of external pollutants are suggested for water-soil-plant system conservation.