This paper examines the factors that drive temporal income diversification in rural areas of the Mekong River Delta in Vietnam, based on a framework that conceptualized diversification as a function of a household’s capacity to diversify and incentives (both push and pull factors) to diversify. Drawing from five rounds of the Vietnam Living Standard Measurement Surveys covering a 13-year span (1993-2006), two panel datasets made from five cross-sectional samples are used for the analyses. The data are drawn from the Vietnam General Statistics Office. Both tobit model and Ordinary Least Squares model with random and fixed effects are applied. The main points emerging from the analysis is that income diversification is strongly influenced by household labor capacity. The relationship between household labor capacity and increasing insertion in non-farming wage activities is not driven by unobserved time-invariant factors such as household ability and motivation, but is instead driven by the higher labor capacity of households. In terms of the other household capacity variables, the effect of farm size is much larger in terms of retaining households in traditional occupations as compared to pushing them towards non-farm wage employment. Other variables such as household access to financial capital do not play an important role.

This study aims to measure the relationship between corporate social responsibility (CSR) and affective commitment (ACO), normative commitment (NCO), and organizational performance in food processing enterprises (FPEs) in the Mekong River Delta, Vietnam. To test the initial model proposed in this paper, a total of 422 owners, directors and managers of FPEs were interviewed from some provinces in the Mekong River Delta. The method of exploratory factor analysis (EFA) is initially employed, then confirmatory factor analysis (CFA) and structure equation modelling (SEM) are used. The results of SEM showed that higher affective commitment was correlated with normative commitment. The results showed that four aspects of CSR toward employees, customers, environment and legal are significant factors. As a result, ACO and NCO act as mediators between CSR and organizational performance. This finding provides strong evidence of the important role of CSR to support positive impacts on ACO, NCO, and orgazational performance (OP). In addition, the success of the organizational performance is also found by contributions of CSR and NCO to its changes. Although ACO does not directly affect performance, it has a positive effect on the NCO. Therefore, it is necessary to enhance the implementation of CSR to promote implementation of organizational commitments.

In this study, water quality levels were classified and water quality indices were calculated and analysed by using the water quality components of living environmental standards monitored 10 years (2008 ~ 2017) at four stations in the West Nakdong River. As a result of analyzing the monthly variation of the water quality components of the living environmental standards, the water quality in the West Nakdong River was worse downstream than upstream, and pollution at the WNR3 located in the downstream of the Jomangang was the most serious. As a result of classification of water quality levels, BOD and COD levels were the lowest, so water quality pollution in the West Nakdong River was found to be highly influenced by organic matters. The water quality index was the lowest in July and August at four stations, so water quality is showing the worst in summer. As a result of analyzing the correlation between the water quality components and the water quality index, the correlation between the TOC and the water quality index was high in the four stations, and the water quality index in the West Nakdong River was dominated by organic matters and nutrients.

본 연구는 경상북도 중북부지역 낙동강 중류의 하천 식물상을 밝히고, 생활형을 파악하여 향후 유사지역 하천에서의 관속 식물상 조사연구에 기초자료를 제공하고자 실시하였다. 현지 조사는 2016년 5월부터 10월, 2017년 4월부터 10월에 걸쳐 영강, 내성천, 병성천, 위천 및 감천 등 5개 하천에서 실시하였고, 조사결과 조사지역에서 생육하는 관속식물은 99과 288속 421 종 4아종 39변종 10품종 등 총 474분류군이었다. 이 중 양치식물은 8과 8속 10종 1변종 등 11분류군, 나자식물은 3과 3속 4종 등 4분류군, 쌍자엽식물 73과 217속 312종 3아종 25변종 8품종 등 348분류군, 단자엽식물 14과 60속 95종 1아종 13변종 2품종 등 111분류군으로 나타났다. 특산식물은 5분류군이 조사되었고, 식물구계학적특정종으로 중요도가 높은 Ⅲ등급 이상을 살 펴보면 Ⅴ등급은 조사되지 않았으며, Ⅳ등급 3분류군, Ⅲ등급 5분류군이 조사되었다. 희귀식물은 7분류군이 조사되었고, 귀화식물은 73분류군으로 조사되었다. 조사지역 소산식물의 생활형 분석결과 Th 159분류군, H 91분류군, HH 68분류군, G 52 분류군, N 35분류군, MM 32분류군, M 25분류군, Ch 12분류군, E 1분류군 등으로 나타났다.

According to this research, the buoyancy force safety review of the buried water pipeline is carried out to determine the safety. In addition, it suggests ways to use as basic data for establishing future maintenance strategy.

Water resources planning and management are, more and more, becoming important issue for water use and flood control due to the population increase, urbanization, and climate change. In particular, the estimating and the forecasting inflow of dam is the most important hydrologic issue for flood control and reliable water supply. Therefore, this study forecasted monthly inflow of Soyang river dam using VARMA model and 3 machine learning models. The forecasting models were constructed using monthly inflow data in the period of 1974 to 2016 and then the inflows were forecasted at 12- and 24-month ahead lead times. As a result, the forecasted monthly inflows by the models mostly were less than the observed ones, but the peak time and the variation pattern were well forecasted. Especially, the VARMA model showed very good performance in the forecasting. Therefore, the result of this study indicates that the VARMA model can be used efficiently to forecast hydrologic data and also used to establish water supply and management plan.

In this study, monthly average values of BOD, COD, and TOC observed for 10 years (2008–2017) in the Nam River were estimated, and monthly variations of BOD, COD, and TOC were analyzed. Monthly average COD was always higher than monthly average BOD; monthly average TOC was high from June to September when rainfall was high. Monthly correlation coefficients between BOD and COD ranged from 0.57 to 0.94, those between BOD and TOC from 0.45 to 0.93, and those between COD and TOC from 0.75 to 0.93. The correlation coefficients were high from November to February when rainfall was low. Regression analyses for monthly average water quality data of the Nam River classified into dry season (October to April) and wet season (May to September) were conducted. Correlation coefficients were higher in the dry season than those in the wet season, and the determination coefficients of linear regression functions for BOD and COD with TOC were also higher in the dry season than those in the wet season. From this study, it can be concluded that it is appropriate to use monthly data to analyze the correlations among BOD, COD, and TOC in the stream. To analyze the relationship between TOC flowing into the stream and BOD/COD, it was found that seasonal characteristics should be considered.

Herein, we analyzed the spatial and temporal variation of DO (dissolved oxygen), BOD (biochemical oxygen demand), and COD (Chemical Oxygen Demand) with the monthly mean observed data for 10 years (2008~2017) in the main stream of the Nakdong River. The water quality of the stations declined in a downstream direction, with the BOD and COD showing their highest values at the ST5 station. From the analysis of the correlation of water quality components at 10 stations, the correlation coefficient between the DO and water temperature was more than –0.90, and that between BOD and Chl-a was 0.48~0.85, and that between COD and TOC was more than 0.65 except for the ST5 and ST10 stations. From the regression analysis using data collected from all stations, the water temperature and DO decreased linearly with a coefficient of determination of 0.90, and the Chl-a and BOD could be described by increasing power functions with a coefficient of determination of 0.83. The TOC and COD followed increasing logarithm functions with a coefficient of determination of 0.58. The TOC efficiency at the 10 stations was estimated and the average efficiencies of BOD and COD were 15.5~36.3% and 57.4~89.6%, respectively.

본 연구에서는 한강유역 산지소하천 미세소유역별 돌발홍수 재현기간을 산정하고, 돌발홍수 실사례를 활용하여 적합성을 평가하였다. 이를 위해 1시간 지속기간의 한계유출량과 SURR 모형으로 모의한 토양포화미흡량으로부터 돌발홍수능을 산정하였다. 이후 돌발홍수능을 초과한 과거 집중호우 사상(2002∼2010년)의 강우량과 재현기간별 유역평균확률강우량을 비교하여 미세소유역별 돌발홍수 재현기간을 산정하였다. 또한, 돌발홍수 실사례(2011∼2016년) 강수량으로부터 추정된 재현기간을 활용하여 적합성을 평가하였다. 돌발홍수 재현기간 산정결과 평균은 1.6년, 표준편차는 1.1로 산정되었으며, 1.1∼19.9년 범위로 나타났다. 적합성 평가결과 돌발홍수 사례별 추정된 재현기간의 83%가 돌발홍수 재현기간 범위 이내로 나타났다. 본 연구에서 산정한 돌발홍수 재현기간의 적합성은 높은 것으로 판단된다.

본 연구에서는 주 단위 지하수자원 관리 취약시기 평가 방법을 개발하였다. 강수의 지하수위에 대한 영향을 고려하기 위하여 한계 침투량을 고려한 강우이동평균 방법을 통해 지하수위와의 상관계수를 산정하였다. 취약 시기 평가 기준을 개발하고 평가 기준에 대한 가중치를 엔트로피 방법을 이용하여 산정하였다. 강수와의 상관계수와 산정된 가중치를 이용한 주 단위 지하수자원 관리 취약시기 평가 방법을 개발하였으며, 개발한 방법을 통하여 소규모 행정구역을 대상으로 취약시기를 평가하였다. 본 연구에서 개발된 방법은 지역적일뿐만 아니라 계절적인 지하수자원의 효율적 관리 대책 수립의 근거가 될 수 있을 것이다.

The purpose of this study was to propose an efficient management plan for purchased land considering the hydrological, watershed characteristics and ecological functions of the target land and surrounding area based on the result of monitoring the water quality improvement effect obtained by purchasing the land in the watershed area in the Geum river system. For this purpose, this study investigated through literature review, and examined ways to apply them to this research by deriving implications from a comprehensive analysis of previous research cases. After that, the components of assessment were derived to evaluate the ecological function of the purchase land, and the ecological function evaluation model for each land and area was proposed. In order to select purchase and restoration priorities of the land, this study analyzed the ecological status of the purchased land in main watersheds and tributaries using Arc GIS ver 10.1. Through this, a process to select restoration priorities was developed. And this study constructed the integrated management process with proposing a mid - to long - term plan by integrating the purchased land valuation and restoration priority selection process. Based on this process, this study suggested an effective management plan for purchased land through the integrated ecological management system of lands purchased. It can be used systematically in appraisal valuation, land purchase system, restoration project, and follow-up management of land purchase.

In this study, the water quality components (pH, BOD, COD, TOC, SS, DO, TP) and the water quality, observed for 10 years (2008~2017) in the five tributaries of the Nakdong River with the highest flow rates, were analyzed. Monthly levels of the water quality components were estimated and regression functions were used to quantitatively explain the changes in the BOD and COD components, with respect to the TOC components. The results of analyzing the water quality levels in terms of the living environmental standards show that the lowest water quality was observed midstream (ST-3) and the highest water quality was observed upstream (ST-1 and ST-2). The regression function was estimated to be a linear function in all five tributaries, and the goodness of fit of the function was high upstream (ST-2), midstream (ST-3), and downstream (ST-4). According to the regression analysis using the observation data from 2008~2017, we found that the consumption of dissolved oxygen increased with an increase in organic matter in the major tributaries of the Nakdong River.

Water quality is characterized by various complex factors. Therefore, a systematic understanding of water quality trends is required to carry out a proper evaluation. In this study, we analyzed the spatio-temporal water quality characteristics of the Nakdong River using five-year data from 2012 to 2016. Data was collected on the pH, DO, BOD, COD, SS, TN, TP, TOC, WT, EC, NH3-N, NO3-N, PO4-P, Chl-a, rainfall, and total and fecal coliforms. A total of 38 water quality measurement stations, from Andong1 to Gupo, were considered. Statistical analyses including trend, cluster, and factor analyses were conducted to identify the dominant water quality components affecting the Nakdong River. The Nakdong River was spatially classified into three groups for up-stream (Andong1 to Sangju1), mid/up-stream (Donam to Dalseong), and mid/down-stream (Hwawonnaru to Gupo) data collection, and temporally into two groups for summer/fall (7~10), and the rest of the season (11~6) data. The water quality of the entire Nakdong River showed trends similar to the mid/down-stream section, which indicates the importance of water quality management in this section. Suspended solids, phosphorus, and coliform groups were established as important factors to be considered in the summer/fall season across the river, especially in the mid/down-stream section. Nitrogen and organic matter were identified as important factors to be considered in the rest of the season, especially in the mid/up-stream section. This study could help determine the water quality components that should be intensively monitored in the Nakdong River.

자연하천 유로의 선형과 단면 형상은 유수 흐름 및 유사이송과의 상호작용에 의해 시·공간적으로 연속적 변화를 거치게 된다. 본 연구에서는 4대강 살리기 사업을 통해 대규모 하상 준설과 시설물 공사가 이루어진 낙동강을 대상으로 인위적 변화가 가해진 유로의 형태학적 특성이 시간이 경과함에 따라 자연적으로 변화해가는 양상을 살펴보고 정량적으로 분석하고자 하였다. 이를 위해 강정고령보∼달성보 구간에 대한 수심 및 하천측량을 실시하고 하도 단면의 기하학적 특성치와 유로 선형(곡률)을 지표로 4대강살리기 사업 완료 후 지형의 변화양상과 형태학적 특성을 파악하고자 하였다. 4대강살리기 사업 종료 후 유의미한 지형변화가 발생하기에는 충분한 시간이 경과하지 않았기에 지형변화의 정도와 양상에서 특별한 경향 성을 추출할 수는 없었다. 하지만 본 연구에서 제안된 방법론을 활용한 지형특성 및 변화의 양상과 규모에 대한 지속적인 평가가 필요할 것으로 판단되는 바이다.

한국에서 현재 사용되고 있는 홍수예보모형은 집중형 강우-유출모형을 적용하여 유역의 유출을 계산하고 하도 및 저수지 추적모형 등을 활용하여 하천의 수위를 예측한다. 집중형 모형은 유역을 동질의 배수구역으로 가정한다. 따라서 유역내의 다양한 공간적 특성을 고려하지 못한다는 단점이 있다. 또한, 사용되는 강우자료도 지점강우를 활용하기 때문에 공간적인 분포를 자세히 고려하지 못한다는 한계가 있다. 따라서 홍수예보모형에 분포형 모형을 적용하기 위한 연구가 다양하게 진행되고 있다. 본 연구에서는 GRM모형을 한국 홍수예보시스템에 적용하기 위해 모형의 다양한 해상도에 따른 유역유출의 결과의 차이를 분석하여 최적의 해상도를 결정하고자 한다. 모형의 격자가 너무 조밀한 경우 계산시간이 과다하게 되어 홍 수예보모형에 적용하기에는 적합하지 않다. 너무 성길 경우에도 분포형 모형을 적용하여 공간적인 분포를 파악하고자 하는 목적에 맞지 않게 된다. 본 연구의 결과로 유역유출 예측의 정확성을 만족시키고 홍수예보에 적합한 계산속도가 나올 수 있는 최적 해상도를 제시하였다. 유출량 예측의 정 확도는 Nash-Sutcliffe model efficiency coefficient (NSE) 값의 비교를 통해 분석하였다. 본 연구에서 도출된 최적해상도 산정 결과는 분포형 유 역유출모형을 홍수예보모형에 적용하기 위한 기초자료로 활용될 것이다.

낙동강 하구의 지형변화 메커니즘을 파악하는 것은 하구의 관리방안과 처리방법 연구에 매우 중요하다. 본 연구에서는 낙동강 하구의 지형변화에 관여하는 강우, 하천유량, 유사량과 같은 육역으로부터 영향과 조석, 조류, 파랑, 표층퇴적물 등과 같은 해역으로부터의 영향을 조사·분석하였다. 분석된 자료에 근거하여 지형변화 실험을 수행하고, 지형변화와 외력조건별 기여도를 분석하였다. 수치실험 결과 지형변화는 하굿둑 방류 영향을 직접적으로 받는 수로부를 중심으로 침식이, 간접 영향권인 간석지를 중심으로 퇴적이 우세하게 나타났다. 수로부를 따라 이동되는 퇴적물이 파랑에 의해 분급, 배분되면서 울타리선 전면부에는 퇴적이 우세하였다. 지형변화 실험결과인 퇴적 우세현상과 비교 하여, 외력조건별로 침식의 기여도가 크게 나타나고 있으나 각 외력조건의 복합적인 영향은 퇴적이 우세하게 나타나고 있다. 따라서, 낙동강 하구의 지형변화는 여러 복합적인 외력인자의 결과로 판단된다. 또한, 각 외력조건별 영향은 구역별로 상이한 기여도를 보이므로 하구관리방안 수립시 이러한 결과를 고려해야 하고, 반드시 복합적인 상호작용의 결과로 이해하고 있어야 할 것으로 사료된다.

하천수사용 관리를 적정하게 관리하기 위해서는 객관적인 하천수사용량 자료가 수집되어야 한다. 그러나, 하천수 사용자의 취수여건을 고려하여 유량계 외에 수문조작 등의 간접적인 계측방법을 인정하고 있고, 사용자의 자발적인 보고에 의존함에 따라 자료의 객관화가 어려운 실정이다. 이에 한강홍수통제소에서는 농업용수 사용 비중이 커 하천유량 파악이 어려운 만경강의 고산~봉동 수위관측소 구간에 위치한 어우보 취수로에 V-ADCP를 이용한 계측시설을 설치 및 운영하고 있다. 본 연구에서는 V-ADCP로 측정된 유속을 이용하여 실시간 하천수사용량 산정을 위한 유속분포법의 적 용성을 평가하였다. 이를 위해 Chiu의 2차원 유속분포식의 매개변수 민감도를 분석하고, 실측유량 자료에 기초한 최적 매개변수를 산정하였다. 또한 수위-유량관계법, 지표유속법과 비교 평가하여 유속분포법의 특성을 분석하였다.

본 연구에서는 기후변화에 따른 메콩강 유출변화 분석을 목적으로 하고 있다. HadGEM3-RA로 부터 생산된 동아시아 지역 RCP 4.5 및 8.5 시나 리오의 일 자료를 기반으로 편의보정을 통해 미래 기후변화 시나리오를 구축한 후, SWAT 모형을 이용하여 메콩강 주요지점인 Kratie(유역면적: 646,000 km2, 메콩강의 연평균 유량의 88%)에서의 유출변화 모의하고 유황분석을 수행하였다. 기후변화 분석 결과 Kratie 유역의 미래 강수량은 기준 년 연평균 강수량 대비 미래 년 기간의 연평균 강수량은 두 시나리오 모두 증가하는 것으로 분석되었으며 월별 강수량 변화 분석을 통해 6 월∼11월에 강수량의 증가가 비교적 크게 나타나며 특히 RCP 8.5 시나리오에서 강수량의 변동 폭 및 증가량이 크게 나타남을 확인하였다. 시나리 오별 월평균 최대 및 최소기온의 변화는 두 시나리오 모두 미래 기온의 상승을 전망하고 있으며 특히 RCP 8.5 시나리오의 온도증가 폭이 크게 나타 나는 것을 확인 하였다. 또한 하천유황변화 분석결과 유역의 유량변동성이 더욱 커질 것으로 분석되었으며 저수계수 값이 52∼57% 감소하고 갈 수계수 값이 67∼74% 감소하는 것으로 나타나 하천의 갈수상황이 지속되어 미래에 가뭄이 보다 심화될 것으로 분석되었다.

Purpose - Urban agglomeration construction is one of national strategic plans to accelerate the development of industrialization and urbanization in China, which has threatened the eco-environmental quality at the same time. This paper selected the urban agglomeration in the middle reaches of the Yangtze River as the research area. Research design, data, and methodology - The the slack-based measurement (SBM) model considering undesirable outputs is applied to measure the eco-efficiency of this urban agglomerations during 2006-2015. Results - The empirical results show that average eco-efficiency of the urban agglomeration in the middle reaches of the Yangtze River is 0.595. Regional ecological development is unbalanced. The highest eco-efficiency is recorded at Wuhan Metropolitan Area, and the lowest one is at the Changsha-Zhuzhou-Xiangtan City Group. Energy consumption and waste dust emissions are the key factors led to ecological inefficiency. Based on this, potentials for energy saving and waste dust reducing are calculated. Conclusions - Finally, this study provides policy implications targeted to promote the coordinating development of economy and eco-environment under the construction of urban agglomeration.

This study aimed to assess the impact of livestock excreta discharged from an Intensive Livestock Farming Area (ILFA) on river water quality during a rainfall event. The Bangcho River, which is one of the 7 tributaries in the Cheongmi River watershed, was the study site. The Cheongmi River watershed is the second largest area for livestock excreta discharge in Korea. Our results clearly showed that, during the rainfall event, the water quality of the Bangcho River was severely deteriorated due to the COD, NH4-N, T-N, PO4-P, T-P, and heavy metals (Cu, Zn, and Mn) in the run-off from nearby farmlands, where the soil comprised composted manure and unmanaged livestock excreta. In addition, stable isotope analysis revealed that most of nitrogen (NH4-N and NO3-N) in the run-off was from the ammonium and nitrate in the livestock excreta. The values of δ15NNH4 and δ15NNO3 for the Bangcho River water sample, which was obtained from the downstream of mixing zone for run-off water, were lower than those for the run-off water. This indicates that there were other nitrogen sources upstream river in the river. It was assumed from δ15NNH4 and δ15NNO3 stable isotope analyses that these other nitrogen sources were naturally occurring soil nitrogen, nitrogen from chemical fertilizers, sewage, and livestock excreta. Therefore, the use of physicochemical characteristics and nitrogen stable isotopes in the water quality impact assessment enabled more effective analysis of nitrogen pollution from an ILFA during rainfall events.