• Title/Summary/Keyword: Drainage Area

Search Result 1,005, Processing Time 0.027 seconds

A Study on Basin Characteristics of Small Stream System (소하천 수계의 유역특성에 관한 연구)

  • An, Sang-Jin;Yun, Yeong-Nam;Gang, Gwan-Won
    • Water for future
    • /
    • v.10 no.1
    • /
    • pp.71-77
    • /
    • 1977
  • The stream morphological characteristics of a watershed play a significant role in the analysis of rainfall-runoff relations in a river basin and a quantitative description of these characteristics is essential for determining the appropriate values of physical parameters of a watershed which usually are input data for rainfall-runoff simulation models. In this study the stream morphological characteristics of the Gab River basin, which is one of the three major tributaries of Geum River, was determined quantitatively by the Horton-Strahler's method. The result showed that the Gab River System was developed very closely to the patterns generally described by the laws of Horton. The basic relations concerning the morphological characteristics deriveed in this study are the relations of stream length, and average stream slope, the stream length-drainage area relation, relative height-relative drainage area relation, and the relation between the proportional stream order and drainage area. No correlation analysis was possible between the morphological parameters and the streamflow due to non-existence of the stage gauging stations on the Gab River System.

  • PDF

Analysis of Influence Factors of Forest Soil Sediment Disaster Using Aerial Photographs - Case Study of Pyeongchang-county in Gangwon-province - (항공사진을 이용한 산지토사재해 영향인자 분석 - 강원도 평창군을 중심으로 -)

  • Woo, Choong-Shik;Youn, Ho-Joong;Lee, Chang-Woo;Jeong, Yongho
    • Journal of the Korean Society of Environmental Restoration Technology
    • /
    • v.11 no.1
    • /
    • pp.14-22
    • /
    • 2008
  • The forest soil sediment disasters occurred in Jinbu-myeon Pyeongchang county were investigated characteristics by the aerial photograph analysis. After digitizing from aerial photographs, forest soil sediment disaster sites were classified into 695 collapsed sites, 305 flowed sites and 199 sediment sites. DEM (Digital Elevation Model) were generated from 1 : 5,000 digital topographic map. Factors of geography, hydrology, biology, and geology were analyzed using DEM, geologic map, and forest stand map with aerial photographs by GIS spatial analysis technique. The forest soil sediment disasters were mainly occurred from southeastern slope to southwestern slope. In collapsed sit es, the average slope degree is $28.9^{\circ}$, the average flow length is 163.5m, the average area of drainage basin is 897$m^2$. In case of flowed sites, the average slope degree, flow length, the area of drainage basin and confluence order is $27.0^{\circ}$, 175m, 2,500$m^2$ and 1, respectively. In sediment sites, the average slope, flow length, the area of drainage basin and confluence order is $12.5^{\circ}$, 2,50m, 25,000$m^2$ and 4, respectively. Also the forest soil sediment disasters were occurred most of collapsed sites in the afforest land after felling and igneous rocks composed of granite.

The Engineering Services on the Go Cong Water Control Project in Vietnam (월남국 고콩지구 수리 개발 기본 조사)

  • 조용칠
    • Magazine of the Korean Society of Agricultural Engineers
    • /
    • v.13 no.4
    • /
    • pp.2471-2478
    • /
    • 1971
  • Go Cong Water Control Project was conducted on its preliminary survey and design by Agricultural development Corporation for the Korean Government, an Executing Agency, and Directorate of Irrigation and Rural Engineering of the Ministry of Land Reform, Agriculture and Fishery Development for the Vietnamese Government, a cooperation Agency, under Korean and Vietnamese Economic and Technical Cooperation Program. The main purposes of the project are aimed at the improvements of irrigation and drainage, and salt water prevention of the Go Cong area located at northern part of the Mekong Delta. All the works from field survey through design to preparing reports were carried out by ADC alone and recently Korean Government submitted the relevant reports to vietnamese Government through official channel. The contents of the project are summarized as following: 1. The project comprises irrigation, drainage and salt water prevention facilities on the benefited area of about 55,000 hectares, covering Go Cong and Dinh Tuong(My Tho) Provinces and it will be possible to cultivate rice cropping twice a year, irrigating all the area in the dry season; 2. With completion of this project, annual production of rough rice and vegetables are anticipated to increase by 222,600 .T. and 142,600 M.T. respectively and the internal rateof return stants at 26 per cent, applying for the exchange rate of US $ 1 to VN $ 275. 3. Total investments required for the project are estimated at US $ 56,394,000 of which actual construction cost is estimated at US $ 39,183,000. The project has planned to be d to be developed by four stages, taking bout 7 years. 4. The project needs for three places of pumping plants. 57Km of feed and main irrigation canals, 81Km of drainage channels, 97Km of dike, 23 places of sluices and navigation locks, etc.

  • PDF

Seasonals Pollutant Outflow Analysis in the Watershed of Soyang Lake by using Multivariate Analysis (다변량 분석을 이용한 소양호 유역의 계절별 오염물질 유출 해석)

  • Park, Soo-Jin
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.13 no.8
    • /
    • pp.3726-3734
    • /
    • 2012
  • This study evaluated the behavior of pollutants based on the seasonal change by selecting the branch river's factors that influence the outflow of pollutants in Soyang lake basin. The analysis method was the factor analysis that classified the factors of the drainage area influencing the outflow of pollutants, and evaluated selected representative factors. As a result of the study, SS and T-P factors should be classified as similar factors to the storm water runoff, and the improvement of water must be strived through managing source of pollution at the time of no rain. Second, as the result of the influence from the factors, spring and winter seasons usually exert 36% influence and summer and fall exert over 90% significant influence that the improvement of water through managing source of water seems possible. At last, the prediction about delivery pollution load considering the outflow characteristic of pollutants at the drainage area based on seasonal change by regarding selected factors as independent variables is possible.

A Study on Obtaining Waters to Restore the Water-ecosystem of Deokjin Pond in Jeonju: New Paradigm for Restoration of Urban Reservoirs (전주시 덕진연못의 수생태 복원을 위한 용수확보방안 연구: 도시 저수지 복원의 새로운 패러다임)

  • Choi, Seung-Hyun;Kim, Seok-Hwi;Lee, Jin Won;Kim, Kangjoo;Oh, Chang Whan
    • Economic and Environmental Geology
    • /
    • v.48 no.6
    • /
    • pp.467-475
    • /
    • 2015
  • The Deokjin Pond is one of the places representing Jeonju City's history but has the poor water quality. The pond has a storage of $88,741m^3$ and a drainage area of $3.77km^2$. It has been maintained only by the groundwater pumped from the upstream wells and the direct rainfalls on the water surface since the old streams replenishing the pond were turned into a part of the sewer system due to indiscreet urbanization. The lack of replenishing water as well as the organic-rich bottom sediment were suggested as two main causes deteriorating the water-ecosystem. In this study, possible measures obtaining waters for restoration of Deokjin Pond ecosystem are discussed. It is estimated that the present pond can be replenished about 32 times a year by the runoff when the drainage system in the watershed is recovered to a state before urbanization. To support this, the drainage system is compared with that of nearby Osong Pond, which shows relatively better water-ecosystem. Even though Osong Pond has a drainage area one-seventh of that of Deokjin Pond, its storage is more than the half of it. It is because its watershed has a near natural drainage system where the rain mostly infiltrates into soil and slowly discharges into the pond. Therefore, it is believed that the low impact development (LID), which is known as a technique restoring the water circulating system to a condition before development, would be helpful in obtaining waters required for Deokjin Pond ecosystem management.

Identification of vulnerable region susceptible to soil losses by using the relationship between local slope and drainage area in Choyang creek basin, Yanbian China (중국 연변 조양하 유역의 국부경사와 배수면적의 관계를 이용한 토사유실 우심지역 추출)

  • Kim, Joo-Cheol;Cui, Feng Xue;Jung, Kwan Sue
    • Journal of Korea Water Resources Association
    • /
    • v.51 no.3
    • /
    • pp.235-246
    • /
    • 2018
  • The main purpose of this study is to suggest a methodology for identifying vulnerable region in Choyang creek basin susceptible to soil losses based on runoff aggregation structure and energy expenditure pattern of natural river basin within the framework of power law distribution. To this end geomorphologic factors of every point in the basin of interest are extracted by using GIS, which define tractive force and stream power as well as drainage area, and then their complementary cumulative distributions are graphically analyzed through fitting them to power law distribution to identify the sensitive points within the basin susceptible to soil losses with respect to scaling regimes of tractive force and stream power. It is observed that the range of vulnerable region by scaling regime of tractive force is much narrower than by scaling regime of stream power. This result seems to be due to the tractive force is a kind of scale dependent factor which does not follow power law distribution and does not adequately reflect energy expenditure pattern of river basins. Therefore, stream power is preferred to be a more reasonable factor for the evaluation of soil losses. The methodology proposed in this study can be validated by visualizing the path of soil losses, which is generated from hill-slope process characterized by local slope, to the valley through fluvial process characterized by drainage area as well as local slope.

A Study on Return Flow Ratio of Irrigation for a Paddy Field in Pumping Station by Water Balance Method (물수지분석 기법에 의한 양수장 몽리구역내 농업용수 회귀율 연구)

  • Choo, Tai-Ho
    • Journal of Korea Water Resources Association
    • /
    • v.37 no.3
    • /
    • pp.249-255
    • /
    • 2004
  • To investigate the return flow ratio of irrigation water, lots of observations were made during the irrigation periods in 2003 crop year. This Area is a portion of Dae-Am pumping station basin which is located in Changryung-gun, Gyeongnam province. A water balance analysis was performed for a paddy field in Dae-Am pumping station in the Nakdong river basin, which is constructed for irrigation water supply. Daily rainfall data in the this area were collected and irrigation water flow rate, drainage water flow rate, infiltration and evaportranspiration were measured in field area. Irrigation water flow rate and drainage water flow rate were continuously observed by water level logger(GTDL-L10) during the growing season. The infiltration and evaportranspiration were measured by cylindrical 300mm depletion meter and cylindrical 200mm infiltrometer, respectively. Total irrigation and drainage flows were 654.7mm and 281.2mm in 2003. Total infiltration and evaportranspiration were 36.0mm and 160.0mm respectively. The mean of the daily evaportranspiration rate was 4.3mmm/d. The prompt return flow and retard return flow ratio were 43.0% and 5.5%, respectively. Total return flow ratio was 48.5%. Therefore, it can be concluded that the amount of irrigation water was much higher than design standard or reference in this study. It means that this was caused by the inadequate water management practice in the area where water was oversupplied on farmers' request rather than following sound water management principles, and design standard should be changed in the future.

Analysis of runoff aggregation structure and energy expenditure pattern for Choyang creek basin on the basis of power law distribution (멱함수 법칙분포를 기반으로 한 조양하 유역의 유출응집구조와 에너지소비 양상에 대한 해석)

  • Kim, Joo-Cheol;Cui, Feng Xue;Jung, Kwan Sue
    • Journal of Korea Water Resources Association
    • /
    • v.50 no.11
    • /
    • pp.725-734
    • /
    • 2017
  • The main purpose of this study is to analyze runoff aggregation structure and energy expenditure pattern of Choyang creek basin within the framework of power law distribution. To this end geomorphologic factors of every point in the basin of interest, which define tractive force and stream power as well as drainage area, are extracted based on GIS, and their complementary cumulative distributions are graphically analyzed through fitting them to power law distribution. The results indicate that three distinct behavioral regimes are observed from the complementary cumulative distributions of three geomorphogic factors. Based on the parameter estimation of power law distribution by maximum likelihood drainage area and stream power can be judged as scale invariance factor without finite scale while tractive force as scale dependence factor with finite scale. Furthermore, it is judged that tractive force would not follow power law distribution because it shows limited complex system behaviors only within the small extent of scale. The exponent of power law distribution for drainage area obtained in this study by maximum likelihood is larger than the previous researches due to the difference of parameter estimation methodologies. And the exponent for stream power is smaller than the previous researches due to the scaling property of channel slope for the basin of interest.

Improving Low Flow Estimation for Ungauged Basins in Korea (국내 미계측유역의 갈수량 산정 개선)

  • Cho, Tak-Guen;Lee, Kil-Seong;Kim, Young-Oh
    • Journal of Korea Water Resources Association
    • /
    • v.40 no.2 s.175
    • /
    • pp.113-124
    • /
    • 2007
  • Low flow is a minimum flow discharging during a dry season in a unregulated stream which can be shared by nature and human being. It is also a standard flow that determines a diversion requirement by evaluating water supply ability of streamflow in the aspect of water use. Low flow indices are used as average low flow and 1-day 10-year low flow in Korea and Japan and as 7-day 10-year low flow in the United States of America and the United Kingdom. In this research, these three indices were compared by the data observed and generated. Although daily records are needed to calculate the low flow, gauging stations are limited and records of the dry season are insufficient in Korea. Drainage-area ratio method is mainly used in Korea to estimate the low flow. This research shows the guideline when the drainage-area ratio method, the regional regression method, and the baseflow correlation method to calculate the low flow of ungauged basins are applied and recommends low flow estimation method suitable to Korea.

A Case Study on the Application of Gravel Pile in Soft Ground (Gravel Pile에 의한 연약지반 개량 시험시공 사례연구)

  • 천병식;고용일;여유현;김백영;최현석
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • 2000.03b
    • /
    • pp.223-230
    • /
    • 2000
  • Sand drain as a vertical drainage is widely used in soft ground improvement. Recently, sand, the principal source of sand drain, is running out. The in-situ tests were carried out to utilize gravel as a substitute for sand. In-situ tests area was divided into two areas by material used. One is Sand Drain(SD) and Sand Compaction Pile(SCP) area, the other is Gravel Drain(GD) and Gravel Compaction Pile(GCP) area. Both areas were monitored to obtain the information on settlement, pore water pressure and bearing capacity by measuring instruments for stage loading caused by embankment. The results of measurements were analyzed, The clogging effect was checked at various depth in gravel column after the test. According to the test results, the settlement was found to be smaller in gravel drain than in sand drain. The increase in bearing capacity by gravel pile explains the result. The clogging effect was not found in gravel column. It is assumed that gravel is relatively acceptable as a drainage material. Gravel is considered to be a better material than sand for bearing capacity, and it is found that bearing capacity is larger when gravel is used as a gravel compaction pile than as a gravel drain.

  • PDF