• Journal of Korea Water Resources Association
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• v.56 no.3
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• pp.165-171
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• 2023

The Nakdong Estuary Barrage is a tidal river environment where freshwater and seawater meet. This requires systematic monitoring of both surface water discharged from the estuary barrage and submarine groundwater discharge. In this study, upstream hydrograph and water balance analysis were used to calculate the change in water storage and discharge of the Nakdong Estuary Barrage. Submarine groundwater discharge was also calculated based on remote sensing-based digital elevation model data and hydrological modeling data, and compared with the estimated surface water discharge for analysis. Our proposed method can be efficiently applied to water resource management by utilizing remote sensing-based altimeter data other than field measurement. Because submarine groundwater discharge plays a significant role on the coastal environment as well as surface water discharge from an estuary barrage, studies on groundwatersurface water interactions in a river estuary should be sufficiently considered in monitoring the ecosystem of the Nakdong Estuary Barrage.

• Ecology and Resilient Infrastructure
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• v.9 no.1
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• pp.1-14
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• 2022

The total maximum daily load (TMDL) implemented in Korea mainly manages the mainstream considering a single common pollutant and river discharge, and the river system is divided into unit watersheds. Changes in the water quality of managed rivers owing to the water quality management in tributaries and unit watersheds are not considered when implementing the TMDL. In addition, it is difficult to consider the difference in the load of pollutants generated in the tributary depending on the conditions of the water quality change in each unit watershed, even if the target water quality was maintained in the managed water system. Therefore, it is necessary to introduce the total maximum load management at tributaries to manage the pollution load of tributaries with a high degree of pollution. In this study, the HSPF model, a watershed runoff model, was applied to the target areas consisting of 53 sub-watersheds to analyze the effect of water quality changes the in tributaries on the mainstream. Sub-watersheds were selected from the three major areas of the Paldang water system, including the drainage basins of the downstream of the South Han-River, Gyeongan stream, and North Han-River. As a result, BOD ranged from 0.17 mg/L to 4.30 mg/L, and was generally high in tributaries and decreased in the downstream watershed. TP ranged from 0.02 mg/L - 0.22 mg/L, and the watersheds that had a large impact on urbanization and livestock industry were high, and the North Han-River basin was generally low. In addition, a pollution source reduction scenario was selected to analyze the change in water quality by the amount of pollution load discharged at each unit watershed. The reduction rate of BOD and TP according to the scenario changes was simulated higher in the watershed of the downstream of the North Han-River and downstream and midstream of the Gyeongan stream. It was found that the benefits of water quality reduction from each sub-watershed efforts to improve water quality are greatest in the middle and downstream of each main stream, and it is judged that it can be served as basic data for the management of total tributaries.

• Journal of Korea Water Resources Association
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• v.46 no.10
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• pp.1017-1028
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• 2013

The purpose of this research is to develop an Integrated Water Resources Evaluation Index (IWREI) which can used to assess the performance of water resources projects in a regional perspective focusing on three major sectors including water use, flood, and river environment in water resources policies. The IWREI is estimated by integrating the Water Use Vulnerability Index (WUVI), the Flood Vulnerability Index (FVI), and the River Environment Vulnerability Index (REVI) which represent the vulnerability in each sector. These indices consist of total 26 indicators selected from the pressure indicators representing the causes of damages in water use, flood, and river environment, the state indicators and the response indicators. The estimated index describes the vulnerability and effectiveness of policies with five levels: Low, Medium Low, Medium, Medium High, and High. The results of evaluating total 115 hydrological units in Korea using the WUVI, FVI, REVI, and IWREI indicate that the project effectiveness in water resources policies is clearly verified by the improved index results compared to the past (early 1990s). Regional vulnerability and evaluation indices developed in this research could be used to establish goals of water resources policy and to select priority regions for project implementation.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.227-227
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• 2015

The Wairarapa Valley occupies a predominantly rural area in the lower North Island of New Zealand. It supports a mix of intensive farming (dairy), dry stock farming (sheep and beef cattle) and horticulture (including wine grapes). The valley floor is traversed by the Ruamahanga River, the largest river in the Wellington region with a total catchment area of 3,430 km2. Environmental, cultural and recreational values associated with this Ruamahanga River are very high. The alluvial gravel and sand aquifers of the Wairarapa Valley, support productive groundwater aquifers at depths of up to 100 metres below ground while the Ruamahanga River and its tributaries present a further source of water for users. Water is allocated to users via resource consents by Greater Wellington Regional Council (GWRC). With intensifying land use, demand from the surface and groundwater resources of the Wairarapa Valley has increased substantially in recent times and careful management is needed to ensure values are maintained. This paper describes the approach being taken to manage water resources in the Wairarapa Valley and redefine appropriate limits of sustainable water use. There are three key parts: Quantifying the groundwater resource. A FEFLOW numerical groundwater flow model was developed by GWRC. This modelling phase provided a much improved understanding of aquifer recharge and abstraction processes. It also began to reveal the extent of hydraulic connection between aquifer and river systems and the importance of moving towards an integrated (conjunctive) approach to allocating water. Development of a conjunctive management framework. The FEFLOW model was used to quantify the stream flow depletion impacts of a range of groundwater abstraction scenarios. From this, three abstraction categories (A, B and C) that describe diminishing degrees of hydraulic connection between ground and surface water resources were mapped in 3 dimensions across the Valley. Interim allocation limits have been defined for each of 17 discrete management units within the valley based on both local scale aquifer recharge and stream flow depletion criteria but also cumulative impacts at the valley-wide scale. These allocation limits are to be further refined into agreed final limits through a community-led decision making process. Community involvement in the limit setting process. Historically in New Zealand, limits for sustainable resource use have been established primarily on the basis of 'hard science' and the decision making process has been driven by regional councils. Community involvement in limit setting processes has been through consultation rather than active participation. Recent legislation in the form of a National Policy Statement on Freshwater Management (2011) is reforming this approach. In particular, collaborative consensus-based decision making with active engagement from stakeholders is now expected. With this in mind, a committee of Wairarapa local people with a wide range of backgrounds was established in 2014. The role of this committee is to make final recommendations about resource use limits (including allocation of water) that reflect the aspirations of the communities they represent. To assist the committee in taking a holistic view it is intended that the existing numerical groundwater flow models will be coupled with with surface flow, contaminant transport, biological and economic models. This will provide the basis for assessing the likely outcomes of a range of future land use and resource limit scenarios.

• Korean Journal of Remote Sensing
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• v.37 no.6_1
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• pp.1589-1597
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• 2021

Submarine groundwater discharge (SGD) in coastal areas is gaining importance as a major transport route that bring nutrients and trace metals into the ocean. This paper describes the analysis of the seasonal changes and spatiotemporal characteristicsthrough the modeling monthly SGD for 35 years from 1986 to 2020 for the Nakdong river basin. In this study, we extracted 210 watersheds and SGD estimation points using the SRTM (Shuttle Radar Topography Mission) DEM (Digital Elevation Model). The average annual SGD of the Nakdong River basin was estimated to be 466.7 m²/yr from the FLDAS (Famine Early Warning Systems Network Land Data Assimilation System) recharge data of 10 km which is the highest resolution global model applicable to Korea. There was no significant time-series variation of SGD in the Nakdong river basin, but the concentrated period of SGD was expanded from summer to autumn. In addition, it was confirmed that there is a large amount of SGD regardless of the season in coastal area nearby large rivers, and the trend has slightly increased since the 1980s. The characteristics are considered to be related to the change in the major precipitation period in the study area, and spatially it is due to the high baseflow-groundwater in the vicinity of large rivers. This study is a precedentstudy that presents a modeling technique to explore the characteristics of SGD in Korea, and is expected to be useful as foundational information for coastal management and evaluating the impact of SGD to the ocean.

• STI Policy Review
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• v.5 no.1
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• pp.98-111
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• 2014

Since Deng Xiaoping's implementation of the "One China, Two Systems" policy, mainland China and the other Chinese regions of Hong Kong and Macau have cooperated in various ways to work towards successfully developing China's overall economy and industries. Particularly, cooperation between Guangdong Province and adjoining Hong Kong have been contributing to China's development, and this study explores their industry conditions including their current two governments policies designed to promote collaboration. The two partners were in a cooperative relationship even before the handover of Hong Kong, beginning with a "front shop, back factory" model built on their respective comparative advantages in labor-intensive industries in the 1980s. This cooperation effectively propelled the Pearl River Delta Region's industrialization process and enabled Hong Kong to transform from a manufacturing industry-based economy to a service industry-based economy. From the early 2000s, Guangdong and Hong Kong diversified their collaboration project from culture to high-tech. Also, both authorities produced several types of policies not only to promote both industries but also to harmonize their two different economic levels and models. As a result, the Guangdong and Hong Kong economies have developed remarkably well during the past two decades and continue to form future plans that carry plenty of optimism. Nonetheless, this study showed discrepancies between engineers and scientists from the two areas in their perception of their technology and science cooperation. Hong Kong experts were more negative in their responses but noted some successes of the collaboration, while Guangdong's group showed overall positive responses. This difference results from an unbalanced role in cooperation. Hong Kong's side responds to cooperation plans and takes on leading roles with more frequency than Guangdong's side in actual cooperation project processes.

• Journal of Environmental Policy
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• v.1 no.1
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• pp.47-74
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• 2002

본 연구에서는 낙동강 하구의 대포천에서의 주민운동을 분석하여 지역사회가 주도하는 환경운동이 특정 조건이 충족된다면 성공적인 환경관리를 할 수 있는 대안이 될 수 있음을 보여준다. 지역사회기반 환경보호(Community-Based Environmental Protection)는 다양한 명칭으로 표현되고 있으나 지역주민의 주도 하에서 환경보호 및 개선을 이룩하는 것으로 지속가능한 사회를 달성할 수 있는 유용한 환경관리 방안으로 이론적인 지지를 받고 있다. 이 방법은 정부의 강압적인 규제보다 효과적일 수 있으며 지역사회의 다양한 욕구와 환경문제를 동시에 고려하게 되는 장점도 있다. 그러나 이러한 지역기반환경운동이 실재 전개되어 성공하는 경우는 흔하지 않다. 그런데 낙동강 하류의 대포천 사례는 지역주민의 환경규제반대운동이 결국에는 주민의 자발적인 수질개선운동으로 발전하여 실질적인 수질개선효과를 창출하였다. 뿐만 아니라 낙동강특별법의 제정 시에 제도화되어 수질환경정책의 발전에도 기여한 특별한 사례이다. 본 연구는 대포천 사례를 우리나라 수질관리정책의 종합적인 체계와 연계시켜서 살펴보면서 대포천 인근지역주민의 수질개선운동의 단계적 전개과정을 살펴보고 이 운동이 성공할 수 있었던 요인을 분석하고 있다.

• Journal of the Korean Solar Energy Society
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• v.38 no.4
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• pp.43-54
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• 2018

In this study, we assessed dependency of small hydropower potentials on the two different runoff such as the estimated runoff based on the rainfall amounts and measured runoff. The hydpropower potentials were evaluated using actural power generations taken from Deoksong, Hanseok, and Socheon small hydropower plants over Han and Nakdong river basins, respectively. As a result of comparing the actual power generation amount with the potential amount based on the rainfall amount and the estimated amount based on the observed flow amount by each small hydroelectric power plant, the degree of latent small hydro energy by the observed flow was confirmed to be high. It is confirmed that the potential hydroelectric power generation rate is estimated to be about average 30%Point higher than the actual generation amount as a result of the measured flow rate rather than using the rainfall amount. Based on this, a method for improving the degree of the actual generation amount is proposed.

• East Asian Journal of Business Economics (EAJBE)
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• v.8 no.4
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• pp.19-28
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• 2020

Purpose - This study aims to lay the foundation for a desirable direction to solve future environmental problems through framework research on environmental cooperation according to distribution of urbanization between South and North Korea. The article also attempts to explore solution to two Koreas' environmental problems from the cooperative perspective between South and North Korea and draw future policy tasks. Research design, data, and methodology - For methodology, North Korea's legal system to cope with disasters is taken into consideration in terms of literature review. This study also analyzes a series of processes related to North Korea's disaster management through case study, and draws policy measures for North and South Korea's cooperation scope and methods. Result - The results support that North Korea is very vulnerable to environmental disasters due to food shortages, economic sanctions, and enormous natural disaster damages including flood damages occurring each year, because of the lack of disaster prevention infrastructure such as river maintenance. Conclusion - At the current time when North and South Koran exchange and cooperation increase, a disaster management cooperative system is needed for the areas where South and North Korea manage through division. It also suggests that there is a need to establish regulations and procedures for support items in advance for a quick response to disasters in North Korean region.

• The Korean Journal of Pesticide Science
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• v.19 no.3
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• pp.255-263
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• 2015

Promoting the organic farming, much of the plant extracts used for controlling pests and fungi have been imported from China, India and Myanmar. But, it is so worrisome that aquatic animals such as muddy loach inhabiting in paddy field and common carps in river exposed to the pests and fungi likely be harmed. This study was conducted in order to evaluate the risks of aquatic animals influenced by the three plant extracts, i.e. Sophora flavescens, Azadirachta indica and Derris elliptica. The toxicities of common carp (Cyprinus Carpio), muddy loach (Misgurnus anguillicaudatus) and PEC (Predicted environmental concentration) exposed to the three plant extracts were estimated by the typical spray volume method. Risks were determined by the toxicity value as 48-hr $LC_{50}$ (Lethal concentration, median) or NOEC (No observed effect concentration) into PEC. 48-hr $LC_{50}$ of Common carp and NOEC by Sophora flavescens extracts was 7.9 and 6.2 mg/L, 26.8 and 21.8 mg/L by Azadirachta indica extracts and 47.0 and < 24.0 mg/L by Derris elliptica extracts, respectively. 48-hr $LC_{50}$ of Muddy loach and NOEC by Sophora flavescens extracts was 16.9 and 10.0 mg/L, 35.6 and 30.0 mg/L by Azadirachta indica extracts, and 73.9 and < 40 mg/L by Derris elliptica extracts, respectively. Therefore, acute toxicities of the three plant extracts for aquatic animals were proved to be very low level. PEC of Sophora flavescens extracts in paddy, drainage and river water was 68.0~3.0, 11.33~0.50 and 3.0~0.0018 mg/L, respectively. TER of Sophora flavescens extracts in the three water was 0.2~5.6, 1.5~33.8 and 2.6~4388.9, respectively. PEC of Azadirachta indica extracts in paddy, drainage and river water was 90.9~1.2, 15.2~0.2 and 4.8~0.00075 mg/L, respectively. TER of Azadirachta indica extracts in the three water was 0.4~29.7, 2.3~178.0 and 4.5~35733.3, respectively. PEC of Derris elliptica extracts in river water was 0.0063 mg/L. TER of Derris elliptica extracts in river water was 5222~15667.