홍은미 Hong Eun Mi , 남원호 Nam Won-ho , 최진용 Choi Jin-yong , 김진택 Kim Jin-taek

DOI: JKWST Vol.56(No.4) 1-8, 2014

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Appropriate amount of water supply to paddy fields in proper time is important to achieve efficient agricultural water management. The purpose of this study is to evaluate the irrigation water supply adequacy for paddy fields using water level data in irrigation canals. For the evaluation, the real-time water level data were collected from main canals in the Dongjin irrigation district for 2 years. Using the water level data, delivered irrigation water amounts at the distribution points of each canal were calculated. The water balance model for paddy field was designed considering intermittent irrigation and the irrigation water requirement was estimated. Irrigation water supply adequacy was analyzed from main canals to the irrigation blocks based on the comparison between estimated requirement and delivered irrigation water amounts. From the adequacy analysis, irrigation water supply showed poor management condition in 2012 with low efficiency except the Daepyong canal section, and the adequacy in 2013 was good or fair except the Yongsung canal section. When irrigation water for paddy fields was insufficient, water supply adequacy was affected by irrigation area, but when irrigation water was enough to supply, adequacy was affected by distance from main canal to distribution points. These results of the spatial and temporal dimensions of the irrigation adequacy could be utilized for efficient irrigation water management to improve the temporal uniformity and equity in the water distribution for paddy fields.

김계웅 Kim Kye Ung , 송정헌 Song Jung Hun , 안지현 Ahn Jihyun , 박지훈 Park Jihoon , 전상민 Jun Sang Min , 송인홍 Song Inhong , 강문성 Kang Moon Seong

DOI: JKWST Vol.56(No.4) 9-19, 2014

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The objective of this study was to evaluate of the Tank model in simulating runoff discharge from rural watershed in comparison to the SWAT (Soil and Water Assessment Tool) model. The model parameters of SWAT was calibrated by the shuffled complex evolution-university Arizona (SCE-UA) method while Tank model was calibrated by genetic algorithm (GA) and validated. Four dam watersheds were selected as the study areas. Hydrological data of the Water Management Information System (WAMIS) and geological data were used as an input data for the model simulation. Runoff data were used for the model calibration and validation. The determination coefficient (R²), root mean square error (RMSE), Nash-Sutcliffe efficiency index (NSE) were used to evaluate the model performances. The result indicated that both SWAT model and Tank model simulated runoff reasonably during calibration and validation period. For annual runoff, the Tank model tended to overestimate, especially for small runoff (< 0.2 mm) whereas SWAT model underestimate runoff as compared to observed data. The statistics indicated that the Tank model simulated runoff more accurately than the SWAT model. Therefore the Tank model could be a good tool for runoff simulation considering its ease of use.

전지홍 Jeon Ji Hong , 김황희 Kim Hwang Hee , 김춘수 Kim Chun Soo , 유성열 Yoo Sung Yeol , 박찬기 Park Chan Gi

DOI: JKWST Vol.56(No.4) 21-28, 2014

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In this study, evaluated ware the strength and durability of the vegetated water purification channel concrete to which recycled aggregates, hawang-toh and jute were applied. Box-Behnken method of response surface analysis in statistics was applied to the experimental design. Experimental variables are as follows, recycled coarse aggregates, hawang-toh, blast-furnace slag and jute fiber. In the experiment, conducted were the tests of compressive strength, chloride ion penetration, abrasion resistance and impact resistance the replacement rate effects of the recycled aggregates, blast-furnace slag and hwang-toh on the performance of vegetated water purification channel concrete were analyzed by using the response surface analysis method on the basis of the experimental results. In addition, an optimum mixing ratio of vegetated water purification channel concrete was determined by using the experimental results. The optimum mixing ratio was determined to be in 10.0% recycled coarse aggregates, 60.0% blast-furnace slag, 10.1% hwang-toh and 0.16% jute fiber. The compressive strength, chloride ion penetration, abrasion rate, and impact number of fracture test results of the optimum mixing ratio were 24.1 MPa, 999 coulombs, 10.30 g/㎣, and 20 number, respectively.

김광섭 Kim Gwangseob , 이기춘 Lee Gichun , 김병권 Kim Beungkown

DOI: JKWST Vol.56(No.4) 29-39, 2014

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In this study, we performed a non-stationary frequency analysis using a power model and the model was applied for Seoul, Daegu, Daejeon, Mokpo sites in Korea to estimate the probable precipitation amount at the target years (2020, 2050, 2080). We used the annual maximum precipitation of 24 hours duration of precipitation using data from 1973 to 2009. We compared results to that of nonstationary analyses using the linear and logistic regression. The probable precipitation amounts using linear regression showed very large increase in the long term projection, while the logistic regression resulted in similar amounts for different target years because the logistic function converges before 2020. But the probable precipitation amount for the target years using a power model showed reasonable results suggesting that power model be able to reflect the increase of hydrologic extremes reasonably well.

소레이멘디옵 Diop Souleymane , 이종원 Lee Jong Won , 이현우 Lee Hyun Woo

DOI: JKWST Vol.56(No.4) 41-51, 2014

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김성필 Kim Seong-pil , 박재성 Park Jae-sung , 배승종 Bae Seung-jong , 허준 Heo Joon

DOI: JKWST Vol.56(No.4) 53-58, 2014

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The objective of this study is to suggest rainfall threshold for landslide forecasting and warning. For this study, we chose the research area where landslide have occurred. And we performed infiltration-stability analysis with rainfall intensity-duration. As the results of this study, slope stability variation chart with rainfall intensity-duration are established. This kind of chart is believed to be able to be used for forecasting and warning the landslide caused by rainfall.

남원호 Nam Won-ho , 홍은미 Hong Eun-mi , 김태곤 Kim Taegon , 최진용 Choi Jin-yong

DOI: JKWST Vol.56(No.4) 59-68, 2014

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Climate change influences multiple environmental aspects, certain of which are specifically related to agricultural water resources such as water supply, water management, droughts and floods. Understanding the impact of climate change on reservoirs in relation to the passage of time is an important component of water resource management for stable water supply maintenance. Changes on rainfall and hydrologic patterns due to climate change can increases the occurrence of reservoir water shortage and affect the future availability of agricultural water resources. It is a main concern for sustainable development in agricultural water resources management to evaluate adaptation capability of water supply under the future climate conditions. The purpose of this study is to predict the sustainability of agricultural water demand and supply under future climate change by applying an irrigation vulnerability assessment model to investigate evidence of climate change occurrences at a local scale with respect to potential water supply capacity and irrigation water requirement. Thus, it is a recommended practice in the development of water supply management strategies on reservoir operation under climate change.

장익근 Jang Ik Geun , 이재용 Lee Jae Yong , 이정범 Lee Jeong Beom , 김진수 Kim Jin Soo

DOI: JKWST Vol.56(No.4) 69-75, 2014

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We investigated flood control capacity of 484 agricultural reservoirs with storage capacity of over 1 million ㎥ in South Korea. In general, agricultural reservoir secures flood control capacity by setting up limited water level during flood season from late June to mid-September. The flood control capacity of an agricultural reservoir during flood season can be divided into stable flood control capacity during non-flood season, stable flood control capacity associated with limited water level, and unstable flood control capacity associated with limited water level. In general, the flood control capacity significantly (P < 0.001) increased with reservoir capacity irrespective of type of spillway. The unstable flood control capacity accounted for about 20 % of reservoir capacity in the uncontrolled reservoirs. The study reservoirs showed flood control capacity of 0.60-65 billion (B) ㎥ and stable flood control capacity of 0.43-47 B ㎥, depending on the upper and lower limited water levels during the flood season. The stable flood control capacity of the gated reservoirs (0.29-0.33 B ㎥) was about two times than that of reservoirs with uncontrolled spillways (0.14 B ㎥). The ratios of stable flood control capacity to reservoir capacity for agricultural reservoirs range from 21 to 23 %, similar to that for Daecheong multipurpose dam. Moreover, the reservoirs with over 100 mm ratio of flood control capacity to watershed area accounted for 38 % of total gated reservoirs. The results indicate that many agricultural reservoirs may contribute to controlling flood in the small watersheds during the flood season.

박정구 Park Jung Koo , 임성윤 Lim Seong Yoon , 송창섭 Song Chnag Seob

DOI: JKWST Vol.56(No.4) 77-82, 2014

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In Korea, length of irrigation and drain canal is about 98,638 km. In the case of 2011, dredging on the irrigation and drain canal was 7,288 km about 3,290,483 ㎥, cost of dredging was about 5.6 billion won and cost of dredging increases every year. (Korea Rural Community Corporation, 2013) In the case of land reclamation, the problem of cross-contamination due to leachate after landfill is expected, causing saturation of the landfill site, or complaints of landfill local residents, a number of problems. The ocean landfill is possible if the items of 14 types as defined in the Sea Pollution Prevention Law contained in sediment soil, such as chromium. In terms of cost and labor, it is need to develop a technology utilizing a processing method reasonable sediments for irrigation and drainage canal. The objective of this study was to analyze the characteristics of the sediment deposited on the irrigation and drain canal. it is to provide basic data for the scheme that can be efficiently recycled sediment deposited on the irrigation and drain canal.