• Title/Summary/Keyword: Water resources development

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Influence of Micrometeorological Elements on Evapotranspiration in Rice (Oryza sativa L.) Crop Canopy (포장(圃場)에서 벼 군락(群落)의 미기상(微氣象) 요소(要素)들이 증발산량(蒸發散量)에 미치는 영향(影響))

  • Kim, Jong-Wook;Kang, Byeung-Hoa;Lee, Jeong-Taek;Yun, Seong-Ho;Im, Jeong-Nam
    • Korean Journal of Soil Science and Fertilizer
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    • v.25 no.3
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    • pp.231-241
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    • 1992
  • To study the relationships between major micrometeorological elements and their influences on evapotranspiration(ET) in the canopy of two rice cultivars, Daecheongbyo and Samgangbyo, synoptic meteorological factors, micrometeorological elements and ET from the canopy and biomass production were observed at various growth stages in the paddy field of Suwon Weather Forcast Office in 1989. ET from the rice community was highly correlated with the following factors in order of pan evaporation>air temperature>leaf temperature>solar radiation>sunshine duration>difference in vapor pressure depicit(VPD)>water temperature. ET observed showed higher correlation with the evaporation from small pan than that from Class A pan. Varietal difference would be noted in the relationships between ET in Samgangbyo canopy and the evaporations observed from the pans, with which closer a correlation was found in Samgangbyo than in Daecheongbyo. The ratio of canopy ET to the evaporation from Class A pan was maintained over 1.0 through the growth stages with the maximum of 1.9 at the late August. The evaporation observed from Class A pan was amounted to 71.9% of that from small pan. ET was better correlated with solar radiation than with net radiation which reached about 66% of solar radiation. Maximum temperature showed higher correlation with ET than mean air temperature, and also wind speed of 1m above ground revealed positive correlation. The relative humidity, however, had no correlation with the exception of ET in rainy days. A regression model developed to estimate ET as a function of meteorological elements being described with $R^2$ of 0.607 as : $ET=-5.3594+0.7005Pan\;A+0.1926T_{mean}+0.0878_{sol}+0.025RH$.

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A Study on Curriculum Development For Community Health Practitioners (보건진료원 직무교육 교과과정 개선을 위한 일 연구)

  • 조원정;이경자
    • Journal of Korean Academy of Nursing
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    • v.22 no.2
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    • pp.207-226
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    • 1992
  • This study was designed to develop a conceptual framework for the curriculum and develop the details of the learning content for the education of Community Health Practitioners (CHPs). Since education programs for CHPs started 10 years ago, concepts related to CHP services have changed because of changes in society. The objectives of the study were as follows : 1) to analyse the usefulness of the present education program for CHPs, 2) to analyse the Job performance and self -confidence of the CHPs, 3) to identify the health needs of the clients served by the CHPs and the community problems related to health. 4) to develop a conceptual framework for the curriculum, for the education of CHPs, 5) to develops details for the learning content of the education program for CHPs. Phase I of the study was conducted by questionnaires to 150 CHPs who have worked in remote rural areas for more than 2 years. Among them, 147 responded. Data was collected from August 16, to August 25, 1990. In order to identify the health needs of the community people, research within the last five years was reviewed and analyzed. The data on 1, 842 communities gathered by the WHO Nursing Collaborations Center of the College of Nursing, Yonsei University was utilized to identify community problems related to health and the self - confidence in job performance of the CHPs. Psase II of the study consisted of a workshop with 13 professionals including Community Health Practitioners to evaluate the existing education program and a conceptual framework of the curriculum for the job education of CHPs. The results of the study are Summariged below : 1. The only 26 among 45 content items of the education program related to job skills was used by 80% of the responding CHPs. The knowledge of $\ulcorner$Networking community organization$\lrcorner$ was used by only 53.7% of the respondents. Educational content about $\ulcorner$Mental disease$\lrcorner$ was used by less than 50% of CHPs because of a knowledge deficit. 2. The CHPs reported that their activities concentrated on clinical services during the last six months. The survey showed that they seemed to neglect the activities for health promotion and disease prevention. Thus, $\ulcorner$Education for community loaders$\lrcorner$(15.9%), $\ulcorner$Activity for eavironmental health$\lrcorner$(16.3%) and $\ulcorner$Social work for needey people$\lrcorner$(23.3%) were done by less than 30% of CHPs. 3. More than 90% of CHPs reported being self - confident for the activities of $\ulcorner$Health education and counselling$\lrcorner$, $\ulcorner$Medicine prescription$\lrcorner$ and $\ulcorner$Immunization$\lrcorner$. But 50% of CHPs reported that they were not have self - confident in $\ulcorner$Management of water and environmental health$\lrcorner$ and only 25.6% of CHPs could insert an IUD independently. 4. It was identified that respiratory diseases and the gastrointestinal diseases were most common problems for the community people, followed by musculoskeletal and skin problems. 5. The community problems were classified into eight categories : physical environmental problems, environmental hygiene, health problems, health behavior, social problem, lack of resources, financial problem and the problems of the cultural and value system. 6. The conceptual framework consisted of the target population and their health status, nursing process working site and primary health care services such as health promotion, disease prevention, treatment and rehabilitation. 7. The contents of curriculum of education program for CHPs were formulated from the results of this study.

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Development of Leaf Protein Concentrates II. Extraction of Leaf Protein Concentrates of Some Plants Growing in Korea (잎 단백질(蛋白質)(Leaf Protein Concentrates)의 개발(開發)에 관한 연구(硏究) II. 한국산(韓國産) 각종 식물(植物)로 부터의 잎 단백질(蛋白質)의 추출(抽出))

  • Choe, Sang;Kim, Geon-Chee;Chun, Myung-Hi;Kim, Kil-Hwan
    • Korean Journal of Food Science and Technology
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    • v.2 no.2
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    • pp.17-25
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    • 1970
  • Juice were extracted from fresh leaves of 70 species of plants growing in Korea by mincing and pressing the resulting pulp through a cotton cloth. Leaf protein concentrates could be prepared from many species of land and water plants that are at present economically unimportant. The choice of plants is of considerable important. Total-N, protein-N and pH determinations were made on the extracts, and total-N remaining in the fibre were calculated. Leaf protein concentrates were precipitated from the extracts at $75{\sim}80^{\circ}C$, and analysed total-N as protein-N of products. The present paper deals with the calculated yields of leaf protein concentrates from various plants, relations between yield of leaf protein concentrates and total-N of leaves, or pH of extracts, and the amino acid compositions of leaf protein concentrates. Results are summarized as follows. 1. Spinach and radish were the best sources of easily extractable, but good results were also obtained with indian mustard, kail, chenopod, red bean, cucumber, squash, houndberry, white flowered gourd, potato, Humulus japonicus, arrowroot and soybean as a good resources for the production of leaf protein concentrates. 2. In general, the greater the protein content of leaves the greater the yield of leaf protein concentrates. However, there are some plants difficult to make a adequate protein extraction by a simple mechanical process. 3. It was to be expected that leaf protein concentrates would be more extractable with the higher pH of extracts. There were a poor yield of the leaf protein concentrate in the pH values lower than 5.50 of the first extracts. 4. Protein content of the leaf protein concentrate shows marked differences, depending on species and season. It ranged between 29 to 80% of protein contents. However, the majority of plants yielded products containing more than 50% of protein. Products containing more than 75% of protein were obtained from two species of radish and indian mustard. Cabbage and Digitaria sanguinalis cilialis (summer) made products containing 29 to 32% of protein. 5. The amino acid composition of leaf protein concentrates was not greatly altered by species of plants. On an amino acid compositional basis, the leaf protein concentrate has a favorable balance of essential and non-essential amino acids, the only exception being methionine, which was usually low in all cases.

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Effect of Submergence and Air Exposure of the Shoot on Growth, Nutrient Uptake and Photosynthesis in Monochoria vaginalis Presl. (물달개비 경엽(莖葉)의 침수여부(沈水與否)에 따른 생장(生長), 양분흡수(養分吸收) 및 광합성(光合成) 비교(比較))

  • Soh, C.H.;Yang, K.S.;Kwon, Y.W.
    • Korean Journal of Weed Science
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    • v.16 no.1
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    • pp.14-20
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    • 1996
  • Growth, nutrient uptake and photosynthesis as affected by submersion of shoot in pickerel weed (Monochoria vaginalis Presl.) were determined. The shoots of pickerel weeds in hydroponic culture were subjected to the submerged or emerged condition at 3- or 5-leaf stage for 8 or 10 days. Under submerged condition, growth in plant height was enhanced, but leaf number, leaf area, fresh and dry weight were reduced compared to those under the emerged condition. Similar responses in growth to submergence were obtained with the pickerel weeds rooted in the soil. Under submergence, chlorophyll content increased during the first 2 days, but thereafter remarkably decreased at 3-leaf stage and after the first 4 days at 5-leaf stage. Compared to the emerged condition, uptakes of $NH_4\;^+$-N, $NO_3\;^-$-N, $P_2O_5$ and $K^+$ were reduced, but uptakes of $Ca^{++}$ and $Mg^{++}$ increased under the submerged condition. Photosynthetic rate of shoot under water, measured by $CO_2$electrode, showed the maximum by 210 ${\mu}$moles $HCO_3\;^-$/g F.W. at the 8th day after submergence(DAS) at 3-leaf stage and 320 ${\mu}$moles $HCO_3\;^-$/g F. W. at 6 DAS at 5-leaf stage. These results indicate that pickerel weeds grow much better when the shoot is air-exposed and are less tolerable to submergence at 3 leaf-stage than at 5-leaf stage.

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Historical Studies on the Nameless Buildings at the Jondeokjeong Area in Donggwoldo (동궐도상의 존덕정 영역에 나타난 무편액 건물의 조영사적 고찰)

  • Jung, Woo Jin;Sim, Woo Kyung
    • Korean Journal of Heritage: History & Science
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    • v.45 no.1
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    • pp.148-173
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    • 2012
  • The rear garden in Donggwol Palace which shared with the Changdeok Palace and the Changgyeong Palace is the salient places of technology and idea reflected the phases of the times of the Joseon Dynasty, so it is certainly one of the best Korean garden cultures. The rear garden in Donggwol which was not only the secret garden for the rest of royal family but also used as symbolic places for the various ceremonies and training its human resources has been considerably destroyed through the period of Japanese colonial rule. Thus the rear garden areas at north of Changkyung Palace were entirely transformed and a few territory from Juhabru(宙合樓) to Ongnyucheon(玉流川) keep up its surviving as the rear garden. The area of Jondeokjeong(尊德亭) which become subject on this studies from among these was constructed as flower garden after development of Ongnyucheon. The areas of Simchujeong(深秋亭), Cheoknoedang(滌惱堂), Pyemwoosa(?愚?), Mangchunjeong(望春亭), Chunhyagak(天香閣), Chungsimjeong(淸心亭) around Jondeokjeong, were situated among the beautiful scenery with the flowers and ponds. But there are only Jondeokjeong and Pyemwoosa at this moment, and the other pavilions was destroyed and transformed. For these reasons, in this studies, the formative purposes were investigated through analysing water elements, planting, ornaments and so on. According to these reasons, historical records and realities of garden construction of five pavilions : Simchujeong, Mangchunjeong, Cheoknoedang, Chunhyagak, Chungyeongak(淸燕閣) were considered to give authenticity to the restoration and reorganization as well as to accumulate basic knowledge about the conservation of environment surrounded garden architectures. These pavilions appeared at Gunggwolgi(宮闕志) and Joseonwangzosilok(朝鮮王朝實), but their names were not appeared at Donggwoldo(東闕圖). So they were ascertained through all of literatures on Donggwol Palace. Cheoknoedang and Simchujeong among these buildings could be found out as the existed buildings and the uncertain building at the northwest of Jondeokjeong was estimated as the name to Chunhyagak or Mangchunjeong. And the hypothesis that the wall surrounding Taichungmoon(太淸門) should be belong to Chungyeongak was supported. In addition, the area which did not known in connection with name and use on northeast at the Changdeok Palace, and had regarded as an impasses in the studies of Donggwoldo and the rear garden in Donggwol Palace, but the historical records of using by Yeonsangun(燕山君) and Sukjong(肅宗) were discovered at this study. And it could be uncovered that the obscure spatial space was a separate house only for king and he enjoyed play there unnoticing to others belong to palace.

Global Rice Production, Consumption and Trade: Trends and Future Directions

  • Bhandari, Humnath
    • Proceedings of the Korean Society of Crop Science Conference
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    • 2019.09a
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    • pp.5-5
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    • 2019
  • The objectives of this paper are (i) to analyze past trends and future directions of rice production, consumption and trade across the world and (ii) to discuss emerging challenges and future directions in the global rice industry. Rice is a staple food of over half of the world's 7.7 billion people. It is an important economic, social, political, and cultural commodity in most Asian countries. Rice is the $1^{st}$ most widely consumed, $2^{nd}$ largely produced, and $3^{rd}$ most widely grown food crop in the world. It was cultivated by 144 million farms in over 100 countries with harvested area of over 163 million ha producing about 745 million tons paddy in 2018. About 90% of the total rice is produced in Asia. China and India, the biggest rice producers, account for over half of the world's rice production. Between 1960 and 2018, world rice production increased over threefold from 221 to 745 million tons (2.1% per year) due to area expansion from 120 to 163 million ha (0.5% per year) and paddy yield increase from 1.8 to 4.6 t/ha (1.6% per year). The Green Revolution led massive increase in rice production prevented famines, provided food for millions of people, reduced poverty and hunger, and improved livelihoods of millions of Asians. The future increase in rice production must come from yield increase as the scope for area expansion is limited. Rice is the most widely consumed food crop. The world's average per capita milled rice consumption is 64 kilograms providing 19% of daily calories. Asia accounted for 84% of global consumption followed by Africa (7%), South America (3%), and the Middle East (2%). Asia's per capita rice consumption is 100 kilograms per year providing 28% of daily calories. The global and Asian per capita consumption increased from the 1960s to the 1990s but stable afterward. The per capita rice consumption is expected to decline in Asia but increase outside Asia especially in Africa in the future. The total milled rice consumption was about 490 million tons in 2018 and projected to reach 550 million tons by 2030 and 590 million tons by 2040. Rice is thinly traded in international market because it is a highly protected commodity. Only about 9% of the total production is traded in global rice market. However, the volume of global rice trade has increased over six-fold from 7.5 to 46.5 million tons between the 1960s and 2018. A relatively small number of exporting countries interact with a large number of importing countries. The top five rice exporting countries are India, Thailand, Vietnam, Pakistan, and China accounting for 74% of the global rice export. The top five rice importing countries are China, Philippines, Nigeria, European Union and Saudi Arabia accounting for 26% of the global rice import. Within rice varieties, Japonica rice accounts for the highest share of the global rice trade (about 12%) followed by Basmati rice (about 10%). The high concentration of exports to a few countries makes international rice market vulnerable to supply disruptions in exporting countries, leading to higher world prices of rice. The export price of Thai 5% broken rice increased from 198 US$/ton in 2000 to 421 US$/ton in 2018. The volumes of trade and rice prices in the global market are expected to increase in the future. The major future challenges of the rice industry are increasing demand due to population growth, rising demand in Africa, economic growth and diet diversification, competition for natural resources (land and water), labor scarcity, climate change and natural hazards, poverty and inequality, hunger and malnutrition, urbanization, low income in rice farming, yield saturation, aging of farmers, feminization of agriculture, health and environmental concerns, improving value chains, and shifting donor priorities away from agriculture. At the same time, new opportunities are available due to access to new technologies, increased investment by the private sector, and increased global partnership. More investment in rice research and development is needed to develop and disseminate innovative technologies and practices to overcome problems and ensure food and nutrition security of the future population.

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Origin and Source Appointment of Sedimentary Organic Matter in Marine Fish Cage Farms Using Carbon and Nitrogen Stable Isotopes (탄소 및 질소 안정동위원소를 활용한 어류 가두리 양식장 내 퇴적 유기물의 기원 및 기여도 평가)

  • Young-Shin Go;Dae-In Lee;Chung Sook Kim;Bo-Ram Sim;Hyung Chul Kim;Won-Chan Lee;Dong-Hun Lee
    • Korean Journal of Ecology and Environment
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    • v.55 no.2
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    • pp.99-110
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    • 2022
  • We investigated physicochemical properties and isotopic compositions of organic matter (δ13CTOC and δ 15NTN) in the old fish farming (OFF) site after the cessation of aquaculture farming. Based on this approach, our objective is to determine the organic matter origin and their relative contributions preserved at sediments of fish farming. Temporal and spatial distribution of particulate and sinking organic matter(OFF sites: 2.0 to 3.3 mg L-1 for particulate matter concentration, 18.8 to 246.6 g m-2 day-1 for sinking organic matter rate, control sites: 2.0 to 3.5 mg L-1 for particulate matter concentration, 25.5 to 129.4 g m-2 day-1 for sinking organic matter rate) between both sites showed significant difference along seasonal precipitations. In contrast to variations of δ13CTOC and δ15NTN values at water columns, these isotopic compositions (OFF sites: -21.5‰ to -20.4‰ for δ13 CTOC, 6.0‰ to 7.6‰ for δ15NTN, control sites: -21.6‰ to -21.0‰ for δ13CTOC, 6.6‰ to 8.0‰ for δ15NTN) investigated at sediments have distinctive isotopic patterns(p<0.05) for seawater-derived nitrogen sources, indicating the increased input of aquaculture-derived sources (e.g., fish fecal). With respect to past fish farming activities, representative sources(e.g., fish fecal and algae) between both sites showed significant difference (p<0.05), confirming predominant contribution (55.9±4.6%) of fish fecal within OFF sites. Thus, our results may determine specific controlling factor for sustainable use of fish farming sites by estimating the discriminative contributions of organic matter between both sites.

A Proposal for Simplified Velocity Estimation for Practical Applicability (실무 적용성이 용이한 간편 유속 산정식 제안)

  • Tai-Ho Choo;Jong-Cheol Seo; Hyeon-Gu Choi;Kun-Hak Chun
    • Journal of Wetlands Research
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    • v.25 no.2
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    • pp.75-82
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    • 2023
  • Data for measuring the flow rate of streams are used as important basic data for the development and maintenance of water resources, and many experts are conducting research to make more accurate measurements. Especially, in Korea, monsoon rains and heavy rains are concentrated in summer due to the nature of the climate, so floods occur frequently. Therefore, it is necessary to measure the flow rate most accurately during a flood to predict and prevent flooding. Thus, the U.S. Geological Survey (USGS) introduces 1, 2, 3 point method using a flow meter as one way to measure the average flow rate. However, it is difficult to calculate the average flow rate with the existing 1, 2, 3 point method alone.This paper proposes a new 1, 2, 3 point method formula, which is more accurate, utilizing one probabilistic entropy concept. This is considered to be a highly empirical study that can supplement the limitations of existing measurement methods. Data and Flume data were used in the number of holesman to demonstrate the utility of the proposed formula. As a result of the analysis, in the case of Flume Data, the existing USGS 1 point method compared to the measured value was 7.6% on average, 8.6% on the 2 point method, and 8.1% on the 3 point method. In the case of Coleman Data, the 1 point method showed an average error rate of 5%, the 2 point method 5.6% and the 3 point method 5.3%. On the other hand, the proposed formula using the concept of entropy reduced the error rate by about 60% compared to the existing method, with the Flume Data averaging 4.7% for the 1 point method, 5.7% for the 2 point method, and 5.2% for the 3 point method. In addition, Coleman Data showed an average error of 2.5% in the 1 point method, 3.1% in the 2 point method, and 2.8% in the 3 point method, reducing the error rate by about 50% compared to the existing method.This study can calculate the average flow rate more accurately than the existing 1, 2, 3 point method, which can be useful in many ways, including future river disaster management, design and administration.

Dynamic Equilibrium Position Prediction Model for the Confluence Area of Nakdong River (낙동강 합류부 삼각주의 동적 평형 위치 예측 모델: 감천-낙동강 합류점 중심 분석 연구)

  • Minsik Kim;Haein Shin;Wook-Hyun Nahm;Wonsuck Kim
    • Economic and Environmental Geology
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    • v.56 no.4
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    • pp.435-445
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    • 2023
  • A delta is a depositional landform that is formed when sediment transported by a river is deposited in a relatively low-energy environment, such as a lake, sea, or a main channel. Among these, a delta formed at the confluence of rivers has a great importance in river management and research because it has a significant impact on the hydraulic and sedimentological characteristics of the river. Recently, the equilibrium state of the confluence area has been disrupted by large-scale dredging and construction of levees in the Nakdong River. However, due to the natural recovery of the river, the confluence area is returning to its pre-dredging natural state through ongoing sedimentation. The time-series data show that the confluence delta has been steadily growing since the dredging, but once it reaches a certain size, it repeats growth and retreat, and the overall size does not change significantly. In this study, we developed a model to explain the sedimentation-erosion processes in the confluence area based on the assumption that the confluence delta reaches a dynamic equilibrium. The model is based on two fundamental principles: sedimentation due to supply from the tributary and erosion due to the main channel. The erosion coefficient that represents the Nakdong River confluence areas, was obtained using data from the tributaries of the Nakdong River. Sensitivity analyses were conducted using the developed model to understand how the confluence delta responds to changes in the sediment and water discharges of the tributary and the main channel, respectively. We then used annual average discharge of the Nakdong River's tributaries to predict the dynamic equilibrium positions of the confluence deltas. Finally, we conducted a simulation experiment on the development of the Gamcheon-Nakdong River delta using recorded daily discharge. The results showed that even though it is a simple model, it accurately predicted the dynamic equilibrium positions of the confluence deltas in the Nakdong River, including the areas where the delta had not formed, and those where the delta had already formed and predicted the trend of the response of the Gamcheon-Nakdong River delta. However, the actual retreat in the Gamcheon-Nakdong River delta was not captured fully due to errors and limitations in the simplification process. The insights through this study provide basic information on the sediment supply of the Nakdong River through the confluence areas, which can be implemented as a basic model for river maintenance and management.

Studies on the Derivation of the Instantaneous Unit Hydrograph for Small Watersheds of Main River Systems in Korea (한국주요빙계의 소유역에 대한 순간단위권 유도에 관한 연구 (I))

  • 이순혁
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.19 no.1
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    • pp.4296-4311
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    • 1977
  • This study was conducted to derive an Instantaneous Unit Hydrograph for the accurate and reliable unitgraph which can be used to the estimation and control of flood for the development of agricultural water resources and rational design of hydraulic structures. Eight small watersheds were selected as studying basins from Han, Geum, Nakdong, Yeongsan and Inchon River systems which may be considered as a main river systems in Korea. The area of small watersheds are within the range of 85 to 470$\textrm{km}^2$. It is to derive an accurate Instantaneous Unit Hydrograph under the condition of having a short duration of heavy rain and uniform rainfall intensity with the basic and reliable data of rainfall records, pluviographs, records of river stages and of the main river systems mentioned above. Investigation was carried out for the relations between measurable unitgraph and watershed characteristics such as watershed area, A, river length L, and centroid distance of the watershed area, Lca. Especially, this study laid emphasis on the derivation and application of Instantaneous Unit Hydrograph (IUH) by applying Nash's conceptual model and by using an electronic computer. I U H by Nash's conceptual model and I U H by flood routing which can be applied to the ungaged small watersheds were derived and compared with each other to the observed unitgraph. 1 U H for each small watersheds can be solved by using an electronic computer. The results summarized for these studies are as follows; 1. Distribution of uniform rainfall intensity appears in the analysis for the temporal rainfall pattern of selected heavy rainfall event. 2. Mean value of recession constants, Kl, is 0.931 in all watersheds observed. 3. Time to peak discharge, Tp, occurs at the position of 0.02 Tb, base length of hlrdrograph with an indication of lower value than that in larger watersheds. 4. Peak discharge, Qp, in relation to the watershed area, A, and effective rainfall, R, is found to be {{{{ { Q}_{ p} = { 0.895} over { { A}^{0.145 } } }}}} AR having high significance of correlation coefficient, 0.927, between peak discharge, Qp, and effective rainfall, R. Design chart for the peak discharge (refer to Fig. 15) with watershed area and effective rainfall was established by the author. 5. The mean slopes of main streams within the range of 1.46 meters per kilometer to 13.6 meter per kilometer. These indicate higher slopes in the small watersheds than those in larger watersheds. Lengths of main streams are within the range of 9.4 kilometer to 41.75 kilometer, which can be regarded as a short distance. It is remarkable thing that the time of flood concentration was more rapid in the small watersheds than that in the other larger watersheds. 6. Length of main stream, L, in relation to the watershed area, A, is found to be L=2.044A0.48 having a high significance of correlation coefficient, 0.968. 7. Watershed lag, Lg, in hrs in relation to the watershed area, A, and length of main stream, L, was derived as Lg=3.228 A0.904 L-1.293 with a high significance. On the other hand, It was found that watershed lag, Lg, could also be expressed as {{{{Lg=0.247 { ( { LLca} over { SQRT { S} } )}^{ 0.604} }}}} in connection with the product of main stream length and the centroid length of the basin of the watershed area, LLca which could be expressed as a measure of the shape and the size of the watershed with the slopes except watershed area, A. But the latter showed a lower correlation than that of the former in the significance test. Therefore, it can be concluded that watershed lag, Lg, is more closely related with the such watersheds characteristics as watershed area and length of main stream in the small watersheds. Empirical formula for the peak discharge per unit area, qp, ㎥/sec/$\textrm{km}^2$, was derived as qp=10-0.389-0.0424Lg with a high significance, r=0.91. This indicates that the peak discharge per unit area of the unitgraph is in inverse proportion to the watershed lag time. 8. The base length of the unitgraph, Tb, in connection with the watershed lag, Lg, was extra.essed as {{{{ { T}_{ b} =1.14+0.564( { Lg} over {24 } )}}}} which has defined with a high significance. 9. For the derivation of IUH by applying linear conceptual model, the storage constant, K, with the length of main stream, L, and slopes, S, was adopted as {{{{K=0.1197( {L } over { SQRT {S } } )}}}} with a highly significant correlation coefficient, 0.90. Gamma function argument, N, derived with such watershed characteristics as watershed area, A, river length, L, centroid distance of the basin of the watershed area, Lca, and slopes, S, was found to be N=49.2 A1.481L-2.202 Lca-1.297 S-0.112 with a high significance having the F value, 4.83, through analysis of variance. 10. According to the linear conceptual model, Formular established in relation to the time distribution, Peak discharge and time to peak discharge for instantaneous Unit Hydrograph when unit effective rainfall of unitgraph and dimension of watershed area are applied as 10mm, and $\textrm{km}^2$ respectively are as follows; Time distribution of IUH {{{{u(0, t)= { 2.78A} over {K GAMMA (N) } { e}^{-t/k } { (t.K)}^{N-1 } }}}} (㎥/sec) Peak discharge of IUH {{{{ {u(0, t) }_{max } = { 2.78A} over {K GAMMA (N) } { e}^{-(N-1) } { (N-1)}^{N-1 } }}}} (㎥/sec) Time to peak discharge of IUH tp=(N-1)K (hrs) 11. Through mathematical analysis in the recession curve of Hydrograph, It was confirmed that empirical formula of Gamma function argument, N, had connection with recession constant, Kl, peak discharge, QP, and time to peak discharge, tp, as {{{{{ K'} over { { t}_{ p} } = { 1} over {N-1 } - { ln { t} over { { t}_{p } } } over {ln { Q} over { { Q}_{p } } } }}}} where {{{{K'= { 1} over { { lnK}_{1 } } }}}} 12. Linking the two, empirical formulars for storage constant, K, and Gamma function argument, N, into closer relations with each other, derivation of unit hydrograph for the ungaged small watersheds can be established by having formulars for the time distribution and peak discharge of IUH as follows. Time distribution of IUH u(0, t)=23.2 A L-1S1/2 F(N, K, t) (㎥/sec) where {{{{F(N, K, t)= { { e}^{-t/k } { (t/K)}^{N-1 } } over { GAMMA (N) } }}}} Peak discharge of IUH) u(0, t)max=23.2 A L-1S1/2 F(N) (㎥/sec) where {{{{F(N)= { { e}^{-(N-1) } { (N-1)}^{N-1 } } over { GAMMA (N) } }}}} 13. The base length of the Time-Area Diagram for the IUH was given by {{{{C=0.778 { ( { LLca} over { SQRT { S} } )}^{0.423 } }}}} with correlation coefficient, 0.85, which has an indication of the relations to the length of main stream, L, centroid distance of the basin of the watershed area, Lca, and slopes, S. 14. Relative errors in the peak discharge of the IUH by using linear conceptual model and IUH by routing showed to be 2.5 and 16.9 percent respectively to the peak of observed unitgraph. Therefore, it confirmed that the accuracy of IUH using linear conceptual model was approaching more closely to the observed unitgraph than that of the flood routing in the small watersheds.

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