• Journal of Korean Society on Water Environment
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• v.26 no.5
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• pp.841-849
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• 2010

Soil erosion is an natural phenomenon. However accelerated soil erosion has caused many environmental problems. To reduce soil loss from a watershed, many management practices have been proposed worldwide. To develop proper and efficient soil erosion best management practices, soil erosion rates should be estimated spatially and temporarily. The Universal Soil Loss Equation (USLE) and USLE-based soil erosion and sediment modelling systems have been developed and tested in many countries. The Sediment Assessment Tool for Effective Erosion Control (SATEEC) system has been developed and enhanced to provide ease-of-use interface to the USLE users. However many researchers and decision makers have requested to enhance the SATEEC system for simulation of soil erosion and sediment reflecting effects of single storm event. Thus, the SATEEC R factors were estimated based on 5 day antecedent rainfall data. The SATEEC 2.1 daily R factor was applied to the study watershed and it was found that the R2 and EI values (0.776 and 0.776 for calibration and 0.927 and 0.911 for validation) with the daily R were greater than those (0.721 and 0.720 for calibration and 0.906 and 0.881 for validation) with monthly R, which was available in the SATEEC 2.0 system. As shown in this study, the SATEEC with daily R can be used to estimate soil erosion and sediment yield at a watershed scale with higher accuracy. Thus the SATEEC with daily R can be efficiently used to develop site-specific soil erosion best management practices based on spatial and temporal analysis of soil erosion and sediment yield at a daily-time step, which was not possible with USLE-based soil erosion modeling system.

• Journal of Soil and Groundwater Environment
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• v.13 no.2
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• pp.44-53
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• 2008

The efficiences of mineral acid (HCl), neutral salts ($CaCl_2$), and chelating agent (citric acid and $Na_2$-EDTA) were tested for extracting heavy metals from open burning and open detonation (OBOD) site soil. The extraction efficiencies of Cd, Cu, Pb and Zn from soil for various extractants were in the order of HCl > citric acid > $Na_2$-EDTA > $CaCl_2$, HCl (1.0 M) extracted effectively 82%, 86%, 80%, and 46% of initial total concentrations of Cd, Cu, Pb, and Zn, respectively. Significant negative correlations were observed between pH of extractant and amount of extracted heavy metals. Initially, examined heavy metals were predominantly bound to carbonate and Fe, Mn-oxide fraction. Though the significant amount of carbonate and Fe, Mn-oxide bounded metals were removed but a significant amount remained metals shifted to exchangeable (more mobile) fraction by HCl and citric acid extraction. The increased mobility of remaining metals could be problematic for water resources, thus careful management is needed to control the movement of heavy metals.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.2
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• pp.225-231
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• 2020

Fresh water that can be used by a person of the total amount of water on the planet is increased because it is less than 0.01 % except underground water, ice and snow, etc. water management response need. In order to protect and efficiently utilize water resources, major countries are conducting water footprint studies that can quantitatively estimate the amount of water put into the operating phase of the resource harvesting phase, mainly agriculture. Korea has also recently developed a number of policies in order to cope with water shortages, and in the construction industry, as well as the need for basic research to support it has been emphasized. This study was constructed DB up to the raw material harvesting step, the transport step, the production stage in order to estimate the water consumption of resources to be put into the work process to target the drainage of the road. Water usage estimation method was utilized the method presented in the Water Footprint Manual and the environmental score card certification guide, unit water usage each drainage main method was calculated after estimating the water footprint considering the water character factor, indirect water and the direct water, the water consumption factor of material input to each process. Brown asphalt, rebar, remicon of the drainage material as a result of the water footprint calculation accounted for 97 % of the total. Drainage method is a culvert, a side channel, a culvert wing wall, reinforced concrete open channel accounted for 92.2 % of the total. Drainage total step-by-step calculated water consumption and water footprint was found in order of raw material harvesting step, transport stage, production stage. Water footprint each drainage method or total drainage material calculated in this study can be used as a base data in the agricultural and construction sectors. In order to increase the reliability of the analysis, it is believed that further overseas databases will be needed for continuous review and research.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.6
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• pp.981-987
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• 2017

Jeju Island is a volcanic island which has a large permeability. Groundwater is a major water resources and its proper management is essential. Especially, there is a multilevel restriction due to the groundwater level decline during a drought period to protect sea water intrusion. Preliminary countermeasure using long-term groundwater level prediction is necessary to use agricultural groundwater properly. For this purpose, the monthly groundwater level prediction technique by Artificial Neural Network model was developed and applied to the representative monitoring wells. The monthly prediction model showed excellent results for training and test periods. The continuous groundwater level prediction model also developed, which used the monthly forecasted values adaptively as input data. The characteristics of groundwater declines were analyzed under extreme cases without precipitation for several months.

• Journal of the Korean Wood Science and Technology
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• v.35 no.2
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• pp.51-60
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• 2007

In this study, the possibility of using pyrolysis oil as wood adhesives was explored. Especially, adhesives were formulated by reacting pyrolysis oil and formaldehyde and also partially replacing phenol with pyrolysis oil in phenol-formaldehyde (PF) adhesive and soy hydrolizate/PF adhesive formulation. The pine wood was fast pyrolyized and the oils were obtained from a series of condensers in the pyrolysis system. The oils from each condenser were first reacted with formaldehyde to explore potential use of the oil itself as adhesive. The lap-shear bond strength test results indicated that the oil itself could be polymerized and form bonds between wood adherends. The oils from each condenser were then mixed together and used as partial replacement of phenol (25, 33, and 50% by weight) in phenol-formaldehyde adhesive. The bond strength of the oil containing PF adhesives was decreased as percent phenol replacement level increased. However, no significant difference was found between 25 and 33% of phenol replacement level. The oil-contained PF resins at 25, 33, and 50% phenol replacement level with different NaOH/Phenol (Pyrolysis oil) molar ratio were further formulated with soy hydrolizate to make soy hydrolizate/pyrolysis oil-phenol formaldehyde adhesive at 6:4 weight (wt) ratio and used for fiberboard manufacturing. Surface internal bond strength (IB) of the boards bonded with 33% replacement at 0.3 NaOH/Phenol (Pyrolysis oil) molar ratio performed better than other replacement levels and molar ratios. Thickness swelling after 24 hr cold water soaking and after 2 hr in boiling water was increased as % replacement of pyrolysis oil increased.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.282-282
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• 2020

본 연구는 여수시 농어촌지역에 대하여 지하수 함양특성, 개발가능량 산정 및 오염부하량 등의 조사를 통해서 체계적인 지하수자원의 보전관리(안)을 수립하기 위해 수행되었다. 연구지역은 여수시 화양면, 소라면 2개 면을 포함하는 농어촌 용수구역(여소지구)으로, 여소지구의 총면적은 130.68 ㎢이며, 이 중 임야면적은 81.57 ㎢, 경지면적은 32.98 ㎢ 이고, 경지면적은 논 15.37 ㎢, 밭 17.42 ㎢, 시설재배 0.19 ㎢로 구성되어 있다. 여소지구의 30년 강수평균은 1,454.08 mm/년이며, 지하수 함양량은 국가지하수관리 기본계획(국토교통부, 2019) 및 전라남도 지하수관리계획(전라남도, 2009) 보고서를 참고하여 평균값인 11.28%로 산정한 결과, 21,279 천㎥/년으로 분석되었다. 또한, 지하수연보(국토교통부, 2018)의 세부용도별 이용량을 활용하여 지하수 이용량을 산정한 결과, 2,638.35 천㎥/년이었으며, 강수량, 함양률 및 면적 값을 고려하여 지하수 개발가능량을 산정한 결과, 16,387.57 천㎥/년, 개발가능량 대비 이용량은 16.11%로 확인되었다. 여소지구의 질산성질소 항목은 총 181개소(경지면적 0.2 ㎢당 1점)에 대해 분석한 결과, 전체 평균값은 6.67 mg/L이었으며, 농업용수 수질기준(20 mg/L)을 초과한 관정은 8개소(6%)로 확인되었다. DRASTIC을 이용한 오염취약성 지수는 평균값이 119.57점으로 나타나 오염취약성이 낮은 것으로 분석되었다. 신고·허가된 축사 시설을 기준으로 점오염원 조사결과, 단위면적당 시설수(오염원밀도)는 3.12 개소/㎢로 조사되었으며, 인구, 가축 및 토지이용 등 인자별을 고려하여 오염부하량을 산출한 결과, 단위면적당 오염부하량은 75.30 kg/day/㎢로 확인되었다. 행정구역별로 7가지 지표를 반영하여 관심, 주의, 경계 및 심각 4단계로 기준을 설정하여 지하수관리 필요지역을 선정하였다. 수량 측면은 개발가능량 대비 이용량, 단위면적당 이용량 및 관정밀 3가지 지표를 적용하였고, 수질 측면은 질산성질소 평균, 오염취약성 지수, 오염원밀도 및 단위면적당 오염부하량 4가지 지표를 적용하여 선정하였다. 지하수관리 필요지역을 분석한 결과, 전체 18개 리 중에서 14개 리에서 수량관리 12개리에서 수질관리 필요지역이 나타났다. 수량관리 필요지역은 지하수 취수량 조정 및 관리 확충 등의 대책방안이 마련되어야 하며, 수질관리 필요지역은 주변 오염원관리 및 수질검사 강화 등의 대책방안이 필요할 것으로 판단된다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.10a
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• pp.357-359
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• 2022

The market for eco-friendly food materials by online distribution is rapidly growing due to major environmental pollution such as air, soil, and water quality, and radical changes in living patterns caused by COVID-19. In addition, because of the aging population and the decrease in agricultural-related population due to social structural changes, aquaponics is emerging as a system that can solve problems such as independence of old economic activities, environmental protection, and securing healthy and safe food. This paper aims to design an intelligent plant growth measurement system among intelligent aquaponics production management modules for optimal growth environment derivation and quantitative production prediction by converging various ICT technologies into existing aquaponics systems. In particular, the focus is on designing systems suitable for production sites that do not have high-performance processing resources, and we propose a module configuration plan for production environments and training data and prediction systems.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1B
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• pp.11-22
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• 2009

Long-term rainfall-runoff modeling is a key element in the Earth's hydrological cycle, and associated with many different aspects such as dam design, drought management, river management flow, reservoir management for water supply, water right permission or coordinate, water quality prediction. In this regard, hydrologists have used the hydrologic models for design criteria, water resources assessment, planning and management as a main tool. Most of rainfall-runoff studies, however, were not carefully performed in terms of considering reservoir effects. In particular, the downstream where is severely affected by reservoir was poorly dealt in modeling rainfall-runoff process. Moreover, the effects can considerably affect overall the rainfallrunoff process. An objective of this study, thus, is to evaluate the impact of reservoir operation on rainfall-runoff process. The proposed approach is applied to Anseong watershed, where is in a mixed rural/urban setting of the area and in Korea, and has been experienced by flood damage due to heavy rainfall. It has been greatly paid attention to the agricultural reservoirs in terms of flood protection in Korea. To further investigate the reservoir effects, a comprehensive assessment for the results are discussed. Results of simulations that included reservoir in the model showed the effect of storage appeared in spring and autumn when rainfall was not concentrated. In periods of heavy rainfall, however, downstream runoff increased in simulations that do not consider reservoir factor. Flow duration curve showed that changes in streamflow depending upon the presence or absence of reservoir factor were particularly noticeable in ninety-five day flow and low flow.

• Journal of Korea Water Resources Association
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• v.54 no.12
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• pp.1243-1254
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• 2021

For water resources operation or agricultural water management, it is important to accurately predict evapotranspiration for a long-term future over a seasonal or monthly basis. In this study, reference evapotranspiration forecast (up to 12 months in advance) was performed using statistically predicted monthly temperatures and temperature-based Hamon method for the Han River basin. First, the daily maximum and minimum temperature data for 15 meterological stations in the basin were derived by spatial-temporal downscaling the monthly temperature forecasts. The results of goodness-of-fit test for the downscaled temperature data at each site showed that the percent bias (PBIAS) ranged from 1.3 to 6.9%, the ratio of the root mean square error to the standard deviation of the observations (RSR) ranged from 0.22 to 0.27, the Nash-Sutcliffe efficiency (NSE) ranged from 0.93 to 0.95, and the Pearson correlation coefficient (r) ranged from 0.97 to 0.98 for the monthly average daily maximum temperature. And for the monthly average daily minimum temperature, PBIAS was 7.8 to 44.7%, RSR was 0.21 to 0.25, NSE was 0.94 to 0.96, and r was 0.98 to 0.99. The difference by site was not large, and the downscaled results were similar to the observations. In the results of comparing the forecasted reference evapotranspiration calculated using the downscaled data with the observed values for the entire region, PBIAS was 2.2 to 5.4%, RSR was 0.21 to 0.28, NSE was 0.92 to 0.96, and r was 0.96 to 0.98, indicating a very high fit. Due to the characteristics of the statistical models and uncertainty in the downscaling process, the predicted reference evapotranspiration may slightly deviate from the observed value in some periods when temperatures completely different from the past are observed. However, considering that it is a forecast result for the future period, it will be sufficiently useful as information for the evaluation or operation of water resources in the future.

• Korean Journal of Remote Sensing
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• v.36 no.6_1
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• pp.1277-1290
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• 2020

Water resources which is formed of surface and groundwater, are considered as one of the pivotal natural resources worldwide. Since last century, the rapid population growth as well as accelerated industrialization and explosive urbanization lead to boost demand for groundwater for domestic, industrial and agricultural use. In fact, better management of groundwater can play crucial role in sustainable development; therefore, determining accurate location of groundwater based groundwater potential mapping is indispensable. In recent years, integration of machine learning techniques, Geographical Information System (GIS) and Remote Sensing (RS) are popular and effective methods employed for groundwater potential mapping. For determining the status of the integrated approach, a systematic review of 94 directly relevant papers were carried out over the six previous years (2015-2020). According to the literature review, the number of studies published annually increased rapidly over time. The total study area spanned 15 countries, and 85.1% of studies focused on Iran, India, China, South Korea, and Iraq. 20 variables were found to be frequently involved in groundwater potential investigations, of which 9 factors are almost always present namely slope, lithology (geology), land use/land cover (LU/LC), drainage/river density, altitude (elevation), topographic wetness index (TWI), distance from river, rainfall, and aspect. The data integration was carried random forest, support vector machine and boost regression tree among the machine learning techniques. Our study shows that for optimal results, groundwater mapping must be used as a tool to complement field work, rather than a low-cost substitute. Consequently, more study should be conducted to enhance the generalization and precision of groundwater potential map.