• 한국관개배수논문집
• /
• 제21권1호
• /
• pp.32-44
• /
• 2014

In Korea, global warming caused by the climate changes impacted on weather system with increase in frequency and intensity of precipitation, and the rainfall pattern changes significantly by regional groups. Furthermore, it is expected that the regional and annual fluctuation ranges of the rainfall in the future would be more severe. Nowadays, agricultural drainage system designed by the existing standard of 20-year return period and 2 days of fixation time cannot deal with the increment rainfall such as localized heavy rain and local torrential rainfalls. Therefore, it is required to reinforce the standard of the drainage system in order to reduce the agricultural flood damage brought by unusual weather. In addition, it is needed to improve the standard of agricultural drainage design in order to cultivate farm products in paddy fields as facility vegetable cultivation and up-land field crop have been damaged by the moisture injury and flooding. In order to prepare for the changes of rainfall pattern due to climate changes and improve the agricultural drainage design standards by the increase of cultivating farm products, the purpose of this study is to examine the impact of climate changes, the changes of relative design standard, and the analytic situation of agricultural flood damages, to consider the drainage design standard revision, and finally to prepare for enhanced agricultural drainage design standards.

• 한국농공학회논문집
• /
• 제65권4호
• /
• pp.25-32
• /
• 2023

KDS (Korean Design Standard) for agricultural drainage is a planning standard that helps determine the appropriate capacity and type of drainage facilities. The objective of this study was to analyze the inundation of the agricultural basin considering the current design standard and the critical rainfall duration. This study used the rainfall durations of 1-48 hour, and the time distribution method with the Chicago and the modified Huff model. For the runoff model, the NRCS (Natural Resources Conservation Service) unit hydrograph method was applied, and the inundation depth and duration were analyzed using area-elevation data. From the inundation analysis using the modified Huff method with different rainfall durations, 4 hours showed the largest peak discharge, and 11 hours showed the largest inundation depth. From the comparison analysis with the current method (Chicago method with a duration of 48 hours) and the modified Huff method applying critical rainfall duration, the current method showed less peak discharge and lower inundation depth compared to the modified Huff method. From the simulation of changing values of drainage rate, the duration of 11 hours showed larger inundation depth and duration compared to the duration of 4 hours. Accordingly, the modified Huff method with the critical rainfall duration would likely be a safer design than the current method. Also, a process of choosing a design hydrograph considering the inundation depth and duration is needed to apply the critical rainfall duration. This study is expected to be helpful for the theoretical basis of the agricultural drainage design standards.

• 한국농공학회지
• /
• 제17권3호
• /
• pp.3840-3847
• /
• 1975

With 30 excisting reservoirs in the Chin-Young area, the Sedimentation of the reservoirs has been calculated by comparing the present capacity with the original value, which revealed its reduced reservoir capacity. The reservoirs has a total drainage area of 3l4l ha, with a total capacity of 43.23 ha-m, and are short of water supply due to reduction of reservoir capacity, Annual sedimentation in the reservoir is relation to the drainage area, the mean of annual rainfall, and the slop of drainage area. The results of obtained from the investigation are summarized as follows: (1) A Sediment deposition rate is high, being about 7.03㎥/ha of drainage area, and resulting in the overage decrease of reservoir capacity by 16.1%. This high rate of deposition coule be mainly attributed to the serve denudation of forests due to disorderly cuttings of tree. (2) An average unit storageof 116mm as the time of initial construction is decreased to 95.6mm at present. This phenomena cause a greater storage of irrigation water, sinceit was assumed that original storage quantity itself was already in short. (3) A sediment deposition rate as a relation to the capacity of unit drainge area is as follow: Qs=1.27(C/A)0.6 and standard deviation is 185.5㎥/$\textrm{km}^2$/year. (4) A sediment deposition rate as a relation to the mean of annual rainfall is as follow: Qs=21.9p10.5 and the standard deviation is 364.8㎥/$\textrm{km}^2$/year. (5) A sediment deposition rate as a relation to the mean slop of drainage area is follow: Qs=39.6S0.75 and the standard deviation is 190.2㎥/$\textrm{km}^2$/year (6) Asediment deposition rate as a relation to the drainage area, mean of rainfall, mean of slope of drainage area is: Log Qs=0.197+0.108LogA-6.72LogP+2.20LogS and the standard deviation is 92.4㎥/$\textrm{km}^2$/year

• 생물환경조절학회지
• /
• 제21권4호
• /
• pp.348-353
• /
• 2012

폐양액을 발생시키지 않는 배액제로형 수경재배기술을 개발하기 위하여 멜론 수경재배 시 표준배액량(배액률 20~40%), 배액최소화(5~10%), 배액제로화(0%) 등으로 배액량을 달리하여 근권환경 변화와 재배기간 동안의 급액량과 배액량, 과실품질 등에 미치는 영향을 구명하였다. 재배기간 동안 표준배액에서는 함수률 60~70%, EC $1.5{\sim}2.5dS{\cdot}m^{-1}$ 수준으로 되어 근권환경이 적정범위로 유지되었다. 배액제로 처리에서는 함수률 30~50%, EC $2{\sim}6dS{\cdot}m^{-1}$로 변화가 심하였으나 과실품질에는 크게 영향을 미치지 않았다. 1과중은 표준배액 처리가 1,990g인데 비하여 배액제로 처리는 1,836g으로 다소 가벼웠으나 규격품(1.8~2.0kg) 생산에는 문제가 없었다. 상품과율은 처리 간에 차이가 없었으며 당도는 배액제로처리가 배액최소와 표준배액에 비하여 높았다. 주당 배액량은 표준배액 처리가 27,718mL, 배액최소 처리가 15,769mL, 배액제로 처리가 2,346mL 이었다. 폐양액 발생량은 표준배액 처리가 10a당 $83.2m^3$로 양액공급량의 34.5% 인데 비하여 배액제로 처리는 $7.0m^3$로 나타나 멜론 수경재배에서 배액제로화의 가능성을 확인할 수 있었다.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2004년도 춘계학술발표회
• /
• pp.678-683
• /
• 2004

The most popular consolidation tester is a standard consolidatiion tester, which performs consolidation using the step load weight. However this apparatus is used to obtain only the vertical consolidation coefficient. Therefore the purpose of this study is to develope the horizontal consolidation cell for a horizaontal consolidation coefficient. Various size of tests have been peroformed to investigate the effect of scale effect. From the test results, it has turned out that this horizontal consolidation cell has a good function for a horizontal consolidation coefficient.

• 한국농공학회:학술대회논문집
• /
• 한국농공학회 2001년도 학술발표회 발표논문집
• /
• pp.451-455
• /
• 2001

This study was performed to examine water and nutrient balance during rice cropping period using difference fertilization paddy plot in ground water irrigation region. The experimental rice paddy consist of three plot, Treatment of Excess fertilization(TEF) and Treatment of Standard Fertilization(TSF) and Treatment of Reduce Fertilization(TRF). As result, input amount to rice paddy was almost rainfall and output was direct runoff through drainage. nutrient input amount was upper paddy in case COD and fertilization in case Total nitrogen and total phosphorus, and output was drainage in all nutrient.

• 한국농공학회:학술대회논문집
• /
• 한국농공학회 2000년도 학술발표회 발표논문집
• /
• pp.96-101
• /
• 2000

Nowadays, everyone emphasis the important of environment. it is found that try to apply using the naturally favorable method when arrange irrigation and drainage channel. But we have no accurate standard of region selection yet. so it is make a many problem. The purpose of this study is the making of standard which is optimal region selection for the creation of the naturally favorable waterfront area. We surveyed data of twenty site in korea where are managed by the KARICO(Korea Agricultural Rural Infrastructure Corporation). We analysed the data using suitable three method(simple adding point method, subjectivity decision method, checklist method) for purpose of this study.

• 한국관개배수논문집
• /
• 제18권1호
• /
• pp.4-17
• /
• 2011

The standard design methodology was suggested to construct wetland system for reducing non-point source pollution from Saemangeum reclaimed paddy land. To set for the design flow and concentrations, runoff and water quality survey were conducted during the irrigation period in 2008 at Gyehwa reclaimed paddy land located at near Saemangeum lake. It is rational that 1ha is the optimum constructed wetland size. To meet this size, the moderate drainage area of reclaimed paddy field was 50ha under the conditions that rainfall is 30mm, average runoff coefficient is 0.83, and runoff capture ratio is 0.6. At these condition, the runoff volume from 50ha was 10,520 $m^3/d$ including base flow during irrigation period. To select the optimum wetland system, several case studies were conducted by focusing on the tidal reclaimed land areas having wetland systems in Seokmun. Pond-Wetland system was selected as the standard model because of showing the highest reduction efficiency. Single variable regression equation were delivered to estimate effluent water concentrations from the designed wetland by using long-term monitoring data from the Seokmun experiment site. The effluent concentration from the designed wetland using these equation were showed moderately range.

• 한국환경농학회지
• /
• 제31권2호
• /
• pp.122-128
• /
• 2012

폐금속 광산에서 유출되는 광산배수로 인한 하류 수계의 환경오염 영향을 검토하기 위하여 삼보광산 하류 수계 내 하천수질, 퇴적토양 및 인근 논토양에 대한 중금속 오염도를 평가한 결과는 다음과 같다. 삼보광산 주변 광미댐 침출수의 Cd 평균 농도(0.018~0.035 mg/L)는 우리나라 농업용수 수질기준(0.01 mg/L)을 초과하였고, 미량성분 중 Zn, Fe 및 Mn 함량도 FAO의 관개용수 최대 권고치(Zn 2.0, Fe 5.0, Mn 0.2 mg/L)를 초과 하였다. 광산 하류 논토양의 Pb, Zn 평균함량은 우리나라 농경지의 토양오염 우려기준(Pb 200, Zn 300 mg/kg)을 초과 하였고, 중금속 오염지수 평균치는 상리가 1.2로 내리지역0.45보다 높게 나타났다. 광산 하류 수계 내 퇴적토의 Cd, Pb 및 Zn 함량은 우리나라 하천용지의 토양오염 우려기준(Cd 10, Pb 400, Zn 600 mg/kg)을 초과하였다. 또한 퇴적토의 중금속 오염지수(PI)는 상리지역 0.98~7.32, 내리지역 0.34~5.27로 지점별 편차가 컸으며, 하류 1km 지점 합류지점(SN-1, SN-2)까지 오염된 것으로 나타났다. 퇴적토의 부화계수(EFc) 평균치는 Cd>Pb>Zn>As>Cu>Cr>Ni 순으로 지점간의 편차가 큰 것으로 나타났다. 퇴적토의 중금속별 지화학적농축계수(Igeo)는 지점별로 약간의 차이는 있으나 Zn>Cd>Pb>Cu>As>Cr>Ni 순으로 높았으며, 특히 Zn의 경우 광산 침출수 영향을 받은 퇴적토에서 경보오염에서 위험오염(Igeo 3.1~6.2) 상태로 심하게 오염된 것으로 나타났다. 결과적으로 삼보광산 하류 하천수질 및 퇴적토의 오염도 평가를 종합해 볼 때 광산 침출수의 영향이 하류 수계 1 km 이상(SN-1, SN-2)까지 미치는 것을 확인할 수 있었다.

• 한국농공학회논문집
• /
• 제47권3호
• /
• pp.77-86
• /
• 2005

A monitoring study has been conducted to identify hydrologic conditions, water quality and nutrient loading characteristics of small watershed in Juam Lake. Climate data of the watershed were collected; flow rate was measured and water quality sampling was conducted at the watershed outlet for this study. Water quality data revealed that T-P concentrations meet I grade of lake water quality standard during non-storm period, but degraded up to II-III grade of lake water quality standard during storm period. The observed T-N concentrations always exceeded lake water quality standard. Therefore, T-P was identified as limiting chemical constituent for eutrophication of Juam Lake. T-P concentration of non-storm period also revealed that point source pollution is not serious in the watershed. Three year monitoring results showed that the observed T-N losses were $10.85\~18.88$ kg/ha and T-P losses were $0.028\~0.323$ kg/ha during six month (Mar. - Oct.), respectively. Major portion of runoff amount discharged by a few storm events a year and nutrient load showed apparent seasonal variation. Huge runoff amounts were generated by intense storms, which make application of water treatment or detention facilities ineffective. Monitoring results confirmed that water quality improvement by abating nonpoint source pollution in rural watershed of monsoon climate should be focused on source control. T-P losses from paddy field seemed to consist of significant amount of total load from study watershed. Therefore, management of drainage from paddy field is considered to be important for preventing algal blooming problem in Juam Lake.