• Journal of Korea Water Resources Association
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• v.56 no.1
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• pp.1-9
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• 2023

Until now, the periods of river discharge management throughout a year are divided into flood and non-flood periods, and the ranges of discharges to be managed are broadly defined from drought discharge to flood discharge. In this study, using the long-term daily discharge data from 8 points of four major rivers, we propose a method of dividing the year into several periods with the homogeneous mean and dispersion of discharges. As a result of the study, the period of through a year was different depending on the point, but it could be divided into pre-flood period, flood period, and post-flood period. And the more subdivided the period, the more decreased the ratio of the maximum discharge to the minimum discharge. In addition, in order to ensure that the discharge for a year is more than the drought discharge and less than the flood discharge, to set the range of discharge management per period as the average flow ± standard deviation for each period is proposed.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.453-453
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• 2022

4대강 유역에 설치되어 운영되고 있는 보의 개방을 통해 하천의 수질 개선 및 자연성 회복을 추진하고자 하는 정부정책에 따라 2017년부터 낙동강 유역 내 일부 보의 수문을 개방하고 모니터링을 진행 중에 있다. 그러나 보 건설 이후, 하천 주변의 농업형태 및 농업용수 취수 조건이 변화하였고, 보 개방에 따른 하천 주변 지역 지하수위 변화로 인한 농업용수 부족 현상이 발생하였다. 정부에서는 보 주변의 농업 현황 조사, 지하수 현황 조사 및 용수 공급 지원 등을 추진하고 있으나, 하천 주변의 농민들은 보 개방으로 인해 발생할 수 있는 농업용수부족 및 이에 따른 농업피해에 대한 우려를 나타내고 있다. 특히 지하수의 지열을 사용하여 겨울철 시설재배 농작물의 보온을 하는 '수막재배' 방법을 활용하는 농가의 경우 지하수위 저하에 따른 난방비 증가 및 농작물 냉해 피해가 발생함에 따라 보 개방에 대한 반대 입장을 고수하고 있다. 하천 주변에 분포하는 지하수는 하천의 영향을 받으며, 지표수와 지하수는 기저유출 등을 통해 상호영향을 받는 물 순환의 구성요소이므로, 보 개방으로 인한 하천수위 변화에 따른 주변지역 지하수위의 변화 패턴에 대한 체계적인 조사와 분석이 필수적이다. 따라서 본 연구에서는 낙동강 보 개방 모니터링을 위한 관측정 설치의 필요성을 조사/분석하고 최적의 관측지점에 설치하여 지속적으로 모니터링을 수행하고자 한다. 이를 통해 보 개방에 따른 주변지역 지하수 영향에 대한 조사 및 분석이 보 개방 모니터링 전후로 수행되어, 보 개방에 따른 지하수 환경 내 영향 분석, 농업형태에 따른 지하수 활용 영향 및 지하수 장애 발생 시 임시대책/항구대책 제시 등을 추진할 수 있어야 한다. 이에 따라 정부와 Kwater는 보 개방에 따른 현장조사 및 분석을 통한 지하수 관측정을 설치하고 지속적인 모니터링을 추진하고 있다. 2019년 현재, 낙동강 유역에는 총 194개소의 지하수 관측정이 있으며, 향후 수막재배를 많이 활용하고 있는 시설재배 농업단지 등을 보 개방에 따른 지하수 이용장애 민원 우려지역을 중심으로 지하수 관측정을 추가로 설치하여 보 개방에 따른 지하수 영향 분석 및 이에 대한 용수공급 대책 마련 등을 위한 기초자료 활용될 것으로 기대한다.

• 대한방사선치료학회:학술대회논문집
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• 2005.06a
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• pp.13-17
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• 2005

Introduction : For stereotactic radiosurgery (SRS) of a tumor in the region whose movement due to respiration is significant, like Lung lower lobe, the gated therapy, which delivers radiation dose to the selected respiratory phases when tumor motion is small, was peformed using the Respiratory gating system and its clinical effectiveness was evaluated. Methode and Materials : For two SRS patients with a tumor in Lung lower lobe, a marker block (infrared reflector) was attached on the abdomen. While patient' respiratory cycle was monitored with Real-time Position Management (RPM, Varian, USA), 4D CT was performed (10 phases per a cycle). Phases in which tumor motion did not change rapidly were decided as treatment phases. The treatment volume was contoured on the CT images for selected treatment phases using maximum intensity projection (MIP) method. In order to verify setup reproducibility and positional variation, 4D CT was repeated. Result : Gross tumor volume (GTV) showed maximum movement in superior-inferior direction. For patient $\#$1, motion of GTV was reduced to 2.6 mm in treatment phases ($30\%\~60\%$), while that was 9.4 mm in full phases ($0\%\~90\%$) and for patient $\#$2, it was reduced to 2.3 mm in treatment phases ($30\%\~70\%$), while it was 11.7 mm in full phases ($0\%\~90\%$). When comparing two sets of CT images, setup errors in all the directions were within 3 mm. Conclusion : Since tumor motion was reduced less than 5 mm, the Respiratory gating system for SRS of Lung lower lobe is useful.

• Korean Journal of Environment and Ecology
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• v.36 no.2
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• pp.150-164
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• 2022

The objective of this study is to analyze the biodiversity changes and characteristics of the benthic macroinvertebrate community in the Nakdong River with eight weirs, which was constructed as one of the Four Major River Restoration Projects from May to October 2020. The study also includes the analysis of changes in the major groups of benthic macroinvertebrates for about ten years, from 2010 to 2020. The surveys collected 97 species of benthic macroinvertebrates belonging to 83 genera, 52 families, 18 orders, five classes, three phyla, and 128.1 individuals/m². Chironomidae sp. and Tubificidae spp., which are pollutant indicators, dominated throughout the sections. The community analysis result shows the average dominant index and the diversity index of 0.62±0.20 and 1.87±0.63, respectively, and indicated the most stability of the freshwater ecosystem in the upper stream of the Nakdong River. The survey showed dominance by Chironomidae sp. at the center of the Nakdong River weir and the most unstable community in Chilgok and Gangjeong Goryeong weirs. The results of the community stability analysis showed a high distribution of the characteristic group I with high resilience and resistance and small distribution of characteristic group III with low resistance and resilience, indicating a very unstable condition of communities in the Nakdong River weir section. Predators were relatively abundant among the functional feeding groups (FFGs), whereas shredders, gathering-collectors, and filtering-collectors were relatively lower. Among the habitat orientation groups (HOGs), burrowers and climbers were dominant, indicating a wide distribution of groups in ecosystems with low dissolved oxygen. An endangered species level II of Macromia daimoji was found in Sangju and Nakdan weirs. The analysis results for 10 years from 2010 showed that the number of species and populations increased immediately after the dam construction but plummeted in 2016 and are now stabilizing. Chironomidae spp. has been dominant in all sections over the past 10 years, and they are currently maintained at a rate of about 50%. The EPT groups have decreased significantly since 2011, and the Plecoptera and Trichoptera of the group have not yet been restored. The population of Tubificidae spp. showed an increase after construction was completed in 2012 and drastically increased in 2015 and 2020. The species of Cristaria plicata, designated as endangered species level I, has not been observed since 2011 in Hapcheon Changnyeong weir. Moreover, Macromia daimoji was rarely observed in seven weirs until 2015, and it has been confirmed that the current distribution habitat has decreased rapidly.

• Journal of Wetlands Research
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• v.16 no.3
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• pp.403-409
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• 2014

Assessment of pollutant loads for livestock manure based on total organic carbon (TOC) is being required to apply TOC as an indicator in management of total maximum daily loads. In this study, TOC based unit loads of pig manure known as highly contributing to water pollution assessed. The concentration of pig manure, amount of manure production including cleaning water, and unit loads were investigated targeting 52 farms according to 4 major river basins, rearing form, farm scale, and piggery form. The manure production was highly generated in scraper type of piggery, in small scaled farm rearing sow, and in Han River basin and Nakdong River basin. The averaged manure production was 7.4 L/head/d in total river basins. Averaged concentrations were investigated as TOC 16,037 mg/L, BOD 10,559 mg/L, TN 4,145 mg/L, and TP 503 mg/L. Corresponding unit loads were assessed as TOC 117.1 g/head/d, BOD 77.1 g/head/d, TN 34.7 g/head/d, and TP 3.67 g/head/d.

• Journal of Korea Water Resources Association
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• v.50 no.9
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• pp.587-595
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• 2017

Hydraulic characteristics affecting sediment transport capacity due to the weir operations were investigated and developed sediment rating curves for four gaging stations (Nakdong, Gumi, Waegwan, and Jindong) in Nakdong River. Analysis found that the sediment transportaion capability had been decreased and it could be proved from the field measurement records in 2013. Applicabilities of nine sediment transport prediction techniques, which are imbeded in GUIDE program, were examined and adopted for the four gaging stations. Analysis of sediment balance for Nakdong River, including 9 major tributaries, had been carried out with pseudo 2-D numerical model and found that: 1) sedimentation phenomena will be prevailed along the Nakdong River. 2) Engelund-Hansen technique shows the least error in estimation of sediment balance. 3) Engelund-Hansen technique most appropriately describes the sediment characteristics for four gaging stations. 4) Estimated error from the sediment balance for Nakdong River was smaller than the error caused by the estimation of sediment incomming from 9 tributries. Therefore, it is necessary to improve the accuracy of predicting the sediment incomming from the tributaties for better sediment balance analysis.

• Clinics in Shoulder and Elbow
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• v.11 no.2
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• pp.123-130
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• 2008

Os acromiale is the rare shoulder disease and its treatment is controversial. Despite conservative treatments for 6 months include medication, exercise, physical therapy and subacromial steroid injections, operative treatment for uncontrolled symptomatic Os acromiale is considered the treatment of choice. Operative treatment includes excision, arthroscopic or open reduction and internal fixation with a bone graft. Open reduction with tension band wiring and a bone graft is now the preferred treatment. We experienced 8 patients with symptomatic Os acromiale from March, 2001 to March, 2006. The average patient's age was 45 years and the man and women ratio were 2: 6. All 8 cases of symptomatic Os acromiale of the mesoacromion were treated with open reduction and internal fixation using tension-band wiring. The preoperative ASES($47.3\pm24.4$) and UCLA ($16.6\pm5.8$)scores were improved to $88.8\pm7.3$ and $31.5\pm1.9$, respectively, at the 2 year follow up. The overall UCLA score showed 1 excellent result and 7 good results. We think that symptomatic Os acromiale is a specific disease entity, and open reduction and internal fixation using tension-band wiring with K-wire is a good treatment modality.

• Journal of Wetlands Research
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• v.19 no.4
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• pp.433-442
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• 2017

As a result of the Four-River Restoration Project in Korea, the habitat of endangered plant species of Aster altaicus var. uchiyamae and Polygonatum stenophyllum, which had been natively grown in the riparian zone of Namhan River, was destroyed and artificial replacement habitats were created. In this study, Habitat Suitability Index (HSI) was used to determine whether the replacement habitats are suitable for each species or not. From October 2015 to July 2016, Habitat Evaluate Procedures (HEP) were conducted on two replacement habitats of A. altaicus var. uchiyamae (Gangcheonsum and Sum-River) and on two replacement habitats of P. stenophyllum (Gangcheonsum and Youngjuk) in the Namhan River watershed. As evaluation parameters for A. altaicus var. uchiyamae habitat, habitat matrix (ratio of unburied gravel), height above the ordinary water level, soil nutrients, and light conditions were selected and for P. stenophyllum habitat, soil texture, light conditions, and coverage of companion species were selected. HSI was applied to evaluate the suitability of each replacement habitat. According to the result of the evaluation, replacement habitats of A. altaicus var. uchiyamae and P. stenophyllum located in Gangcheonsum have relatively high HSI values as 0.839 and 0.846, respectively. On the other hand, replacement habitats of A. altaicus var. uchiyamae in Sum-River and P. stenophyllum in Youngjuk zone have HSI value of 0, indicating unsuitable habitats for these species. This is the first attempt to apply HSI for plant species in Korea and proved the usefulness of HSI on plants.

• Analytical Science and Technology
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• v.22 no.5
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• pp.386-394
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• 2009

Formaldehyde is used in lether manufacture, a dry plate and an explosive. It is by-product of ozonizing process in filtration plant. The effects of exposure are eye pruritus, tickle, runing nose, blocking nasal passages and headache. It also makes a dried throat and causes inflammation. It is classified as B1 group for inhalation by US. EPA, which can cause cancer in human. For analysis of formaldehyde, formaldehydes-DNPH derivative was extracted with solid cartridge and was analyzed by High Performance Liquid Chromatography/Diode Array Detector (HPLC/DAD). The detection limit was $3{\mu}g/L$ and the recoveries were 72.3~109.1% (RSD 2.9~11.5%). Water samples were collected in four Korean rivers, four times per year seasonally for 10 years from 1998 to 2007. The monitoring results were 48.8% (630/1291), $5.15{\sim}101.9{\mu}g/L$ in purified water. Because of non-carcinogen in drinking water, hazard index is calculated with RfD. Results of excess cnacer risk was below 1 and was considered as safe value.

• Journal of Korea Water Resources Association
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• v.45 no.9
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• pp.929-941
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• 2012

In recent years, interest in river environment such as riparian landscape, water quality and ecological conservation has been growing with increasing recreation on agricultural river watershed. That caused the increase of necessity of water resources development, one of solutions for the diversification of agricultural water demand and shortages. In this respects, heightening irrigation dam, as a part of the 4-major river restoration project, is necessary to secure not only additional agricultural water but also instream flow for water quality improvement. However, operation plan of irrigation dam still not be clear. In this study, additional storage which secured through heightening irrigation dam was estimated using SWAT model. And instream flow effects on water quality of downstream were evaluated. The findings show that the additional water supply will contribute positively to water quantity and quality of downstream. The results show a 2~10% water quality improvement effect on nutrients, as well as an 1~8% water quantity increasing effect. In particular, additional storage can be effectively supplied from February to April by the reservoir operation. However, maintaining better water quality in irrigation reservoirs is important because the water quality of irrigation reservoirs can be negatively impacts the water quality in downstream of reservoirs.