• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2019년도 학술발표회
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• pp.149-149
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• 2019

Gross Primary production (GPP) and evapotranspiration (ET) are the two critical components of carbon and water cycle respectively, linking the terrestrial surface and ecosystem with the atmosphere. The ratio between GPP to ET is called ecosystem water use efficiency (EWUE) and its quantification at the forest site helps to understand the impact of climate change due to large scale anthropogenic activities such as deforestation and irrigation. This study was conducted at the FLUXNET forest site CN-Qia (2003-2005) using Community land model (CLM 5.0). We simulated carbon and water fluxes including GPP, ecosystem respiration (ER), and ET using climatic variables as forcing dataset for 30 years (1981-2010). Model results were validated with the FLUXNET tower observations. The correlation showed better performance with values of 0.65, 0.77, and 0.63 for GPP, ER, and ET, respectively. The model underestimated the results with minimum bias of -0.04, -1.67, and -0.40 for GPP, ER, and ET, respectively. Effect of climate 'CLIM' and '$CO_2$' were analyzed based on EWUE and its trend was evaluated in the study period. The positive trend of EWUE was observed in the whole period from 1981-2010, and the trend showed further increase when simulated with rising $CO_2$. The time period were divided into two parts, from 1981-2000 and from 2001 to 2010, to identify the warming effect on EWUE. The first period showed the similar increasing trend of EWUE, but the second period showed slightly decreasing trend. This might be associated with the increase in ET in the wet temperate forest site due to increase in climate warming. Water use efficiency defined by transpiration (TR) (TWUE), and inherent-TR based WUE (IT-WUE) were also discussed. This research provides the evidence to climate warming and emphasized the importance of long term planning for management of water resources and evaporative demand in irrigation, deforestation and other anthropogenic activities.

• 한국물환경학회지
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• 제34권6호
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• pp.669-677
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• 2018

Torrential rain and drought are repeated due to the increase in the unpredictable fluctuating of rainfall patterns. It is time for stabilize water resource management in terms of disaster prevention. Distributed control from sources is needed to minimize damages caused by torrential rains and droughts. Rain barrel can be used to reduce the runoff as they collect and store rainwater. In response to this situation, Seoul Metropolitan Government and other local governments implemented a project to support the installation of rain barrel and provided 90% of the cost of installing it in private areas. However, with limited budget, it is difficult to distribute rainwater to the city which is mostly covered by private areas. In this study, Samho-dong, Ulsan, where pilot projects of water cycle leading city are underway, analyzed the effects of reducing the runoff with respect to the amount of rainwater that can be used, and analyzed the economics of recoverable investment cost when installed. From the analysis, it was established that it is possible to show sufficient efficiency with a small capacity without the need to install large rain barrel effectively in the private sector, and to support the installation cost of less than 70 percent of the rainwater can be recovered.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.581-584
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• 2005

A district heating(DH) system supplies environmentally-friend heat and is appropriate for reduction of energy consumption and/or air pollutions. The objectives of this paper are to systematize data processing of transition temperature, investigate its effects on fatigue life of DH pipes and optimization for size of DH pipes. A relational database management system as well as reliable fatigue life evaluation procedures is established for Korean DH pipes. Also, since the prototypal evaluation results satisfied both cycle-based and stress-based fatigue criteria. Through the optimum design process, the cross section diminished 18.64% and the CUF diminished 23.35%. So, it can be used as useful information in the future for optimal design, operation and energy saving via setting of efficient condition and stabilization of water temperature.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2005년도 춘계 학술기술논문발표대회 논문집
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• pp.13-16
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• 2005

Generally, as corrosive protection processing of a steel structure, zinc galvanizing and heavy duty coating paint are applied. However, zinc galvanizing has the difficulty of restriction of a size, or on-site construction. Moreover, heavy duty coating paint has a problem with many administrative and maintenance expenses with short problem of adhesion, corrosion generating of a damage portion, and maintenance management cycle. In this study, a salt water spray test, CASS test, and the electrochemistry examination were carried out for the thermal metal spray method of construction for corrosive protection performance evaluation. Moreover, the corrosive protection life of a thermal metal spray method of construction was quantitatively calculated on the basis of this experiment. in consideration of LCC, the economical efficiency of a general corrosive protection method of construction and a thermal metal corrosive protection method of construction was compared. Consequently, although initial construction expense was estimated 16 to $30\%$ high, as for a thermal metal spray method of construction, it turns out that the administrative and maintenance expenses for 100 years became cheap 9.3 to 13 or more times.

• 방사성폐기물학회지
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• 제14권1호
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• pp.21-33
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• 2016

Estimation of groundwater hydrologic cycle pattern is one of the most critical issues in sustainable management of groundwater resources in coastal area. This study estimated groundwater percolation by using the water balance methodology and hydrogeological characteristics of land use and soil. Evapotranspiration was computed by using the Thornthwaite method, and surface runoff was determined by using the SCS-CN technique. Groundwater storage change was obtained as 229 mm/a (17.8% of the average annual rainfall, 1286 mm/a), with 693 mm/a (60.1%) of evapotranspiration and 124 mm/a (9.6%) of surface runoff. Rainfall and groundwater storage change was highly correlated, comparing with the relationships between rainfall and evapotranspiration, and between rainfall and surface runoff. This result indicates that groundwater storage change responds more sensitively to precipitation than evapotranspiration and surface runoff.

• Advances in environmental research
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• 제2권4호
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• pp.279-290
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• 2013

In this study, a comprehensive model developed to estimate greenhouse gas (GHG) emissions from urban area with low impact development (LID) and its integrated management practices (IMPs). The model was applied to the actual urban area in Asan Tangjeong district (ATD) as a case study. A rainwater tank (1200 ton) among various LID IMPs generated the highest amount of GHG emissions ($3.77{\times}10^5kgCO_2eq$) and led to the utmost reducing effect ($1.49{\times}10^3kgCO_2eq/year$). In the urban area with LID IMPs, annually $1.95{\times}104kgCO_2eq$ of avoided GHG emissions were generated by a reducing effect (e.g., tap water substitution and vegetation $CO_2$ absorption) for a payback period of 162 years. A sensitivity analysis was carried out to quantitatively evaluate the significance of the factors on the overall GHG emissions in ATD, and suggested to plant alternative vegetation on LID IMPs.

• 한국GIS학회:학술대회논문집
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• 한국GIS학회 1999년도 추계학술대회 발표요약문
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• pp.21-25
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• 1999

Planning support systems(PSS) add more advanced spatial analysis functions than Geographic information systems(GIS) and intertemporal functions to the functions of spatial decision support systems(SDSS). This paper reports the continuing development of a PSS providing a framework that facilitates urban planners and civil engineers in conducting coherent deliberations about planning, design and operation & maintenance(O&M) of water-distribution networks for urban growth management. The PSS using dynamic optimization model, modeling-to-generate-alternatives, value engineering(VE) and life-cycle cost(LCC) can generate network alternatives in consideration of initial cost and O&H cost. Users can define alternatives by the direct manipulation of networks or by the manipulation of parameters in the models. The water-distribution network analysis model evaluates the performance of the user-defined alternatives. The PSS can be extended to include the functions of generating sewer network alternatives, combining water-distribution and sewer networks, eventually the function of planning, design and O&H of housing sites. Capacity expansion by the dynamic water-distribution network optimization model using MINLP includes three advantages over capacity expansion using optimal control theory(Kim and Hopkins 1996): 1) finds expansion alternatives including future capacity expansion times, sizes, locations, and pipe types of a water-distribution network provided, 2) has the capabilities to do the capacity expansion of each link spatially and intertemporally, and 3) requires less interaction between models. The modeling using MINLP is limited in addressing the relationship between cost, price, and demand, which the optimal control approach can consider. Strictly speaking, the construction and O&M costs of water-distribution networks influence the price charged for the served water, which in turn influence the. This limitation can be justified in rather small area because price per unit water in the area must be same as that of neighboring area, i.e., the price is determined administratively. Planners and engineers can put emphasis on capacity expansion without consideration of the relationship between cost, price, and demand.

• 한국물환경학회지
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• 제34권5호
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• pp.462-469
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• 2018

There are differences in method and cycle of flow rate survey depending on purpose of the operating department. To verify and use results of flow data according to the purpose, flow data of the directly measured and tele monitoring system were compared to verify validity. Flow measurement in the Ministry of Environment is aimed at setting up a standard flow of target water quality for water quality management and securing flow data of low and normal water level seasons for water quality evaluation. In this study, correlation analysis result ($R^2$) of same time zone data by direct measurement and tele monitoring system (TMS) at Seombon D point, a unit watershed of Seomjin river, for six years ('10 ~ '15) according to implementation of Total Daily Maximum Load (TDML) was wading 0.716, boating 0.962 and on bridge 0.943, and effectiveness of measurement method was verified by characteristics of flow duration as a season of dry and low-water; normal and high water are appropriate for wading, boating, and on bridge respectively. Results revealed it is reasonable to use directly measured results using the wading and boating method for low water level and dry seasons, and TMS data for rainy seasons. It can be used important data for future policy decisions.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2016년도 학술발표회
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• pp.482-486
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• 2016

광주광역시 도심유역의 14개 단위유역(영본B02~영본B25)으로 면적 $501.19km^2$ 중 약 42%에 해당하는 $211.86km^2$을 대상유역으로 분산식 빗물관리에 의한 물순환 체계를 구축하였다. 지목별 저감대상 면적은 대지, 창고, 공장용지는 전체면적의 15%, 주유소, 학교, 잡종지, 종교용지, 주차장은 5%, 도로는 10%를 적용하여 저감대상 산출면적은 $9.1km^2$로 설정하였으며, 초기강우 10mm에 대한 초기강우유출량 $90,885m^2$이 발생하며 이는 각 단위유역의 토지이용별로 침투통, 침투측구, 침투화분, 침투도랑, 수목여과박스, 식생수로, 빗물저금통, 투수블럭의 8개 시설에 의해 침투 및 저류하는 것을 제안하였으며, 또한, 본 연구의 대상유역에서 발생하는 비점오염원 발생부하량은 8,439.16kg/일으로 그 중 2.4%에 해당하는 210.186kg/일이 본 연구에서 제안한 빗물 관리시설에 의해서 삭감되는 것으로 분석되었다. 또한, 빗물관리시설의 총 투자비용은 약 322억원이며, 효과 비용은 343억원으로 산정되었다.

• 한국수자원학회논문집
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• 제55권8호
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• pp.603-611
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• 2022

도시지역에서는 도시화로 인해 불투수면적이 지속적으로 증가하고 있고, 이는 빗물이 지표하로 침투 및 침루되는 기작을 방해하여 대부분의 빗물이 표면유출되도록 하고 있어 물순환의 왜곡이 심화되고 있다. 물순환의 왜곡은 강우-유출로 인한 수재해 뿐만 아니라, 하천 건천화 및 수질 악화, 생태계 균형 파괴 등 다양한 방면에 영향을 미치는데, 이러한 문제점을 해결하기 위해 환경부에서는 저영향개발 기법의 활용을 적극 권장하고 있다. 저영향개발 기법을 적용하기 위해서는 대상지 개발 이후의 유출증가량을 처리할 수 있는 빗물관리 목표량을 설정해야하는데, 현행 기준에서는 10년 강우 기간의 일단위 강우사상으로 빗물관리 목표량으로 제시하고 있어, 강우기간 및 대상에 대한 개선 연구가 필요하다. 본 연구에서는 물순환 개선을 위한 빗물관리 목표량의 설정에 무강우 지속시간(IETD)을 이용한 독립 강우사상의 구분과 통계분석을 통해 현행 기준과의 차이를 분석하였다. 부산광역시의 1991년에서 2020년까지 30년 강우자료를 이용하여 자기상관계수 분석, 변동계수 분석, 연평균 강우사상 발생개수 분석 등의 방법을 적용하였고, 대상 강우기간에 따라 무강우 지속시간을 선정하였다. 모집단의 표본이 많을수록 무강우 지속시간이 증가하는 경향을 보였다. 또한, 무강우 지속시간에 따른 독립 강우사상의 강우량 규모별 지속시간과 시간분포를 분석하여 빗물관리 목표량에 따라 표준 설계강우량을 산정할 수 있는 방안을 제시하였다. 이에 본 연구와 같이 무강우 지속시간의 선정을 통해 독립 강우사상들의 충분한 표본을 이용한다면, 보다 개선된 빗물관리 목표량을 설정이 가능할 것으로 기대된다.