• Parasites, Hosts and Diseases
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• v.57 no.2
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• pp.135-144
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• 2019

There have been some reports on schistosomiasis of school children in Sudan's Nile River basin area; however, information about the infection status of Schistosoma species and intestinal helminths among village residents of this area is very limited. Urine and stool samples were collected from the 1,138 residents of the Al Hidaib and Khour Ajwal villages of White Nile State, Sudan in 2014. The prevalence of overall schistosomiasis and intestinal helminthiasis was 36.3% and 7.7%, respectively. Egg positive rates were 35.6% for Schistosoma haematobium, 2.6% for S. mansoni, and 1.4% were mixed. The prevalence of schistosomiasis was significantly higher in men (45.6%) than in women (32.0%), in Khou Ajwal villagers (39.4%) than in Al Hidaib villagers (19.2%), and for age groups ${\leq}15$ years old (51.5%) than for age groups >15 years old (13.2%). The average number of eggs per 10 ml urine (EP10) of S. haematobium infections was 18.9, with 22.2 eggs in men vs 17.0 in women and 20.4 in Khou Ajwal villagers vs 8.1 in Al Hidaib villagers. In addition to S. mansoni eggs, 4 different species of intestinal helminths were found in the stool, including Hymenolepis nana (6.6%) and H. diminuta (1.0%). Collectively, urinary schistosomiasis is still prevalent among village residents in Sudan's White Nile River basin and was especially high in men, children ${\leq}15$ years, and in the village without a clean water system. H. nana was the most frequently detected intestinal helminths in the 2 villages.

• Korean Journal of Ecology and Environment
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• v.45 no.2
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• pp.150-157
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• 2012

Fish communities in river networks provide significant ecosystem services that will likely decline under future land use and climate change. We developed a model that simulates the consequences to multiple populations of one or more fish species-a meta-community-from multiple stressors across a river network. The model is spatially-explicit and age-structured, with three components: habitat suitability; population dynamics, including species interactions; and movement across a spatial network. Although this model is simple, it can form the basis of fisheries assessments and may be incorporated into an integrated modeling system for watershed management and prediction.

• Journal of Plant Biology
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• v.15 no.s
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• pp.33-49
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• 1972

Recently two thousand year old several villages ruins discovered at Amsadong, Daeshimli and Hunbaukol near the Han River side in Korea. An investigation of the present flora of these three localities was done. There are 84 families including 419 species of vascular plants. The vegetations of flora in the localities of the Han River side are very similar. the forests are poorly developed and appear as the secondary vegetations. The reforest plants can be recognized as Pinus rigida, quercus acutissima, Q. serrata, Robinia pseudoacacia and Alnus hirta. Herbaceous plants of Miscanthus sacchariflorus and Phragmitis japonicus bind up the soiles of the Han River side. Populus nigra grows abundantly in the moist places of sand bars which are located on the river side south of Daeshimli and on the northern side of the Han River across from Hunbaukol. These three area are fully cultivated but still many primitive farm techniques are employed. Farm produce crops include rice, corn, barley wheat, other vegetables, and a few ornamental plants. In this study the author found flower color variations ranging from a dark blue to a pale blue, and chromosome number differences existing between the populations of Commelina communis. The dark blue flowered taxa chromosome number is 44 and in the pale blue taxa it is 72. The wild white flowered Chrysanthemum is Chrysanthemum zawadskii Herb. ssp. acutilobum and which has finely lobed leaves, and has 54 chromosome in the root tip cells.

• Water for future
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• v.11 no.2
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• pp.54-61
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• 1978

An attemption of synthesizing and forecasting of monthly river flow has been made by employing a linear stochastic difference equation model. As one of the linear stochestic difference equation model, an ARIMA Type is tested to find the suitability of the model to the monthly river flows. On the assumption of the stationary covariacne of differenced monthly river flows the model is identrfield and is evaluated so that the residuale have the minimum variance. Finally a test is performed to finld the residerals beings White noise. Monthly river flows at six stations in Han River Basin are applied for case studies. It was found that the difference operator is a good measure of forecasting the monthly river flow.

• Ecology and Resilient Infrastructure
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• v.3 no.3
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• pp.207-211
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• 2016

This study focuses on the categorization of the phenomenon of vegetative recruitment on riparian channels, so called, the phenomenon from "white river" to "green river", and proposes for the corresponding research direction. According to the literature review and research outputs obtained from the authors' previous research performed in Korea within a limited scope, the necessary and sufficient conditions for the recruitment and retrogression of riparian vegetation may be the mechanical disturbance (riverbed tractive stress), soil moisture (groundwater level, topography, composition of riverbed material, precipitation etc.), period of submergence, extreme weather, and nutrient inflow. In this study, two categories, one for the reduction in spring flood due to the change in spring precipitation pattern in unregulated rivers and the other for the increase in nutrient inflow into streams, both of which were partially proved, have been added in the categorization of the vegetative recruitment and retrogression on the riparian channels. In order to scientifically investigate further the phenomenon of the riparian vegetative recruitment and retrogression and develop the working riparian vegetative models, it is necessary to conduct a systematic nationwide survey on the "white to green" rivers, establishment of the categorization of the vegetation recruitment and retrogression based on the proof of those hypotheses and detailed categorization, development of the working mathematical models for the dynamic riparian vegetative recruitment and retrogression, and adaptive management for the river changes.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.114-114
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• 2011

1960년대 산업화와 도시화 이전 우리나라 하천은 모래, 자갈 사주가 경관생태의 대부분을 이룬 이른바 'White River'이었으나, '70년대 이후 댐건설, 하천정비 등으로 유황과 유사이송 특성이 변하면서 수변에 식생이 번무하는 이른바 'Green River'가 진행 중이다. 하천에서 식생활착은 생태 측면에서 생물 종의 다양성에 일부 긍정적인 역할을 하는 반면에, 고유종이 감소, 소멸하는 문제가 생긴다. 치수 측면에서는 흐름저항 증가와 하도의 고착화를 촉진시켜 치수 안정성에 문제를 야기할 수 있다. 본 연구는 사주 상 식생활착 현상을 정량적으로 규명하기 위한 연구의 시작으로서, 하천 식생사주역에서 식생활착에 직접적인 영향을 주는 소류력과 토양 수분 등 2대 물리 요소 중에서 후자에 초점을 맞추어 토양수분 요인과 식생 이입, 활착, 천이와의 관계를 규명한다. 이를 위해 모래하천인 낙동강 제1지류 내성천의 국가하천 구간 하류 지점인 회룡포 직상류 약 4km 지점을 시험하천 구간으로 선정하여 하천수위, 지하수위, 토양수분을 연속적으로 측정할 수 있는 시설을 설치하였다. 이러한 관측 시설을 가지고 1차적으로 2010년 8월부터 2011년 4월 초까지 지하수위와 하천수위, 토양수분을 연속적으로 모니터링하고 상호 관계를 분석하였다. 사주 상 식생 활착 특성도 주기적으로 조사하였다. 이번 일차 기초 조사 및 분석 결과, 하안에서 약 140-240m에 위치한 지하수위 관측정에서 측정된 지하수위는 하천수위 변화에 비해 시간적으로 약 20시간 지체되는 것으로 나타났다. 한편 사주 토양수분은 일반적으로 지하 깊이에 따라 커지나, 동시에 토층구조(soil texture)에 영향을 받는 것으로 나타났다.

• Journal of Wetlands Research
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• v.13 no.2
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• pp.329-341
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• 2011

This study was conducted with the national river, Munsancheon, which is located in Paju-si, Gyeonggi-do. The sediment discharge of Munsancheon was directly measured to analyze the sediment characteristics, and the results were used in the numerical model to predict the long-term river bed variation. The flow-total sediment discharge relation was derived using the measured total sediment discharge, and the results were compared with the total sediment discharge that was calculated using the existing prediction formula to derive a proper sediment discharge prediction method. In the actual measurements, the total annual sediment discharge was 5,478 ton/year, and the specific sediment discharge was 29.23 ton/$km^2$/year. The Ackers & White formula resulted in the values very close to the actual measurements. With the actual sediment discharge, geographical and hydrologic data as the input variables, HEC-6 and GSTARS models were comparatively analyzed. The test results showed that the HEC-6 model is suitable for the reliable prediction of the long-term river bed variation. Accordingly, the model was used for the long-term river bed variation prediction in this study. In the case of Munsancheon, deposition was continued in the downstream area and erosion occurred in the upstream area on the whole. It was expected that the stream would be stabilized in the river bed condition of 20 years later. The river bed variation was within 1 m, which was at the significance level. In the downstream area that is influenced by tide, however, the accumulation was continuously increasing within the section 2,000-7,000 m from the outlet. It seems that this should be considered in establishing the river management plans.

• Spatial Information Research
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• v.12 no.3
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• pp.229-237
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• 2004

Debris flow in the mountainous river gives rise to serious environmental and flooding problems. According to flood white book of Kangwon-do in 2002, over 30% of total of flooding victims are attributable to debris flow. But it has been neglected to build countermeasure to minimize victims due to lack of collected data and knowledge in field of the sediment yield of mountainous river. The study calculated hydraulic and hydrological fluctuation for rainfall condition using GIS data, after all we estimated the water surface of flood caused by bed fluctuation. These efforts will of for effective information for planning of river management.

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2008.10a
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• pp.113-115
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• 2008

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.6
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• pp.1264-1270
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• 2006

In this study, semi-two dimension numerical model(GSTARS 2.1 model) were applied to study on the hydraulic and sedimentologic characteristics of downstream channel section in Dal stream. GSTARS 2.1 model was applied for the four selected sediment transport formulas(Meyer-Peter and Muller, Acker and White's, Engelund and Hanson, Yang formula) from 1984 to 1992 measured data on each section. The simulation results of Meyer-Peter and Muller formula for long-term bed changes are good when compared to the measured data. When quantitatively compared, it appears that the results data is relatively underestimated compared to the 1992 measured data on each section. Using Meyer-Peter and Muller formula, analyse the effects of bed changes by stream tube number.