• 한국농공학회지
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• 제40권4호
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• pp.58-66
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• 1998

Irrigation Reservoir Water Supply Index(IRWSI), which can be applied to the effective supply and management of the irrigation water resources, was developed. IRWSI was formulated as resealed nonexceedance probabilities of two hydrologic components : reservoir storage ratio and precipitation. To generate nonexceedance probability of hydrologic component, it was important to define the optimal one among the various probability distribution function in the state of nature. To define an optimal probability distribution, in this study, four types of probability distribution function were tested by the K-S fitting, and for the calculation of IRWSI, reservoir storage ratio(%) and precipitation used Normal distribution & Gamma distribution, respectively. In this study, the weight coefficients of a and b for each hydrologic component, which is precipitation and reservoir storage ratio, was decided as 0.8 and 0.2, respectively. While some studies changed weight coefficients according to the size of basin area, this study used same values without considering that. From the analysis of drought characteristics, it was found that the IRWSI was sensitive to the size of irrigation area rather than the size of basin area, and the south-eastern region of Korea had been suffered from severe drought damage.

• 한국수자원학회논문집
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• 제42권10호
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• pp.825-843
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• 2009

농업가뭄에 대한 대책 마련을 위해서는 가뭄기간 동안의 농업용 수리시설에 의한 용수공급 가능량의 파악이 매우 중요하다. 본 연구에서는 네트워크 물수지 모형인 MODSIM을 이용하여 농업용 수리시설을 고려한 물수지 네트워크를 구성하고 36개년(1967-2002) 동안의 물수지 분석을 수행하여 농업용수 공급측면의 가뭄을 평가하였다. 분석 결과, 과거 가뭄발생 기간에 농업용수 부족량이 다른 기간에 비해 많이 발생함을 확인할 수 있었으며, 대표적인 가뭄 년인 1994, 1995, 2001년의 부족량은 745.8백만 m$^3$, 661.1백만 m$^3$, 696.8백만 m$^3$으로 분석되었다. 또한 소유역 평균 용수공급 가능량은 생 공용수의 경우 99.1 %, 농업용수의 경우 84.4 %로 비교적 낮은 공급 가능율을 보였으며, 1994, 1995, 2001년의 농업용수공급 가능량은 74.8 %, 79.2 %, 77.9 %로 소유역 평균보다 낮은 수준으로 분석되었다. 농업용 수리시설물의 기여도 평가를 수행한 결과 양수장과 보의 기여율은 32.5 %, 집수암거와 관정의 기여율은 4.0 %로 분석되었으며, 집수암거와 관정은 양수장과 보에 비해서 상당히 적은 기여율을 갖지만 농업가뭄 해소에 어느 정도 도움을 주는 것으로 분석되었다.

• 한국관개배수논문집
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• 제17권2호
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• pp.57-70
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• 2010

This study was performed to analyze the affect of water supply capacity followed by allocating flood control volume in heightening reservoir, of which Baekgog reservoir was selected as a case study in here. Baekgog reservoir is located in Jincheon county, Chungbuk province, of which full water level will be heightened from EL. 100. 1m to EL. 102.1m, and total storage from 21.75M $m^3$ to 26.67M $m^3$. Flood inflow with 200year frequency was estimated to 997 $m^3$/s in peak flow and 22.54M $m^3$ in total volume. Reservoir flood routing was conducted to determine flood limited water levels, which was determined to have scenarios such as EL 97-98-99m in periods of 6.21.-7.20., 7.21.-8.20., and 8.21.-9.20., respectively, EL 97-97-97m, EL 98-98-98m in present reservoir, and EL 99-100-101m, EL 99-99-99m, and EL 100-100-100m in heightened reservoir. Reservoir inflow was simulated by DAWAST model. Annual paddy irrigation requirement was estimated to 33.19M $m^3$ to 2,975ha. Instream flow was allocated to 0.14mm/d from October to April. Operation rule curve was drawn using inflow, irrigation and instream flow requirements data. In case of withdrawal limit reservoir operation using operation rule curve, reduction rates of annual irrigation supply before and after flood control by reservoir were 2.0~4.3% in present size and 1.5~3.6% in heightened size. Reliability on water supply was decreased from 77.3% to 63.6~68.2% in present size and from 81.6% to 72.7~79.5% in heightened size. And reduction rates of water storage at the end of year before and after flood control by reservoir were 7.3~16.5% in present size and 7.7~16.9% in heightened size. But water supplies were done without any water deficiency through withdrawal limit reservoir operation in spite of low flood regulating water level.

• 한국농공학회논문집
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• 제51권5호
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• pp.101-106
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• 2009

The previous study developed the Filter-Disinfection-Adsorption (FDA) system to provide clean irrigation water for greenhouse cultivation as well as convenience water to farmers. In this study, the field examination was undertaken to assess performance of the FDA system. The field application was made in the suburb of Daegu, one of the large city in Korea. The study area located near by down-stream of Gum-Ho river is suffering low irrigation water quality problems with no water supply service facilities. Four water quality parameters including Suspended Solid (SS), Biological Oxygen Demand (BOD), coliform, and turbidity were selected to test the purification performance of FDA system. Also in order to improve the system, this study investigated the defects of using the FDA system through field monitoring. As results, it was found that this system can be used to supply good quality of irrigation water for greenhouse cultivation and also provide convenience water to farmers in the field areas of no water supply services.

• 한국관개배수논문집
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• 제14권2호
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• pp.214-224
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• 2007

This study was carried out to investigate of water quality and irrigation water use possibility of reservoirs near Saemangeum for upland and horticultural fields. Water samples were taken at 6 reservoirs for 5 months from June, 2006 to November, 2006. The water temperature, pH, EC, EC, chlorophyll - a of 6 reservoirs were ranged 8.7-$31.2^circC$, 6.9-9.2, 73.0-637.0$\mu$S/cm, 0.9-443.2mg/$m^3$, respectively. The concentration of DO, BOD, COD, T-N, T-P and SS were ranged 5.7-11.7mg/L, 0.5-8.9mg/L, 2.9-18.0mg/L, 0.07-6.52mg/L, 0.002-0.406mg/L, 0.5-54.0mg/L Also, storage ratio and storage capacity of Mije reservoir, Okgu reservoir, Oknyeo reservoir, Neungje reservoir were decreased between June and April, but those of Oksan reservoir was kept high during irrigation period. Water supply of reservoirs was 4,474,100$m^3$(Oksan), 6,165,900$m^3$(Mije), 13,209,900$m^3$(Okgu), 4,675,600$m^3$(Oknyeo), 7,682,000$m^3$(Neungje), 19,231,000$m^3$(Cheongho) in 2006, respectively. It is resevoirs for upland and horticultural fields that use main irrigation water resources before Saemanguem fresh-water lake development, and use assistance irrigation water resources in emergency after Saemanguem fresh-water lake development. In the meantime, for continuous use of reservoir as irrigation water resource for upland and horticultural fields, we must examine about surplus water capacity, and need investigation about supply possibility of irrigation water, condition of irrigation water, water quality.

• 한국농공학회지
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• 제44권7호
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• pp.74-82
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• 2002

There are two major operation and management (O & M) systems in Korea, one by the Korea Agricultural and Rural Infrastructure Corporation (KARICO), a government corporation, and the other by non-KARICO, which includes Irrigation associations (IAs) and individual farmers under the supervision of city or county authorities. Main issues and constraints in the irrigation facility management are: (1) The dual system of the irrigation water management system; management by KARICO and that by IAs, and (2) From the commencement of KAICO in 2000, farmers were exempted from water charge. This is opposite to the international trend, which follows' user pay principle: Main specific strategies to improve irrigation management system are: (1) Introduction of water metering for water charge as well as water conservation, (2) Adoption of demand-oriented irrigation rather than supply-oriented to reduce waste of water, (3) To augment farmer's participation by forming water user associations, (4) To maintain consistency of government policy, (5) To promote roles of local governments, and (6) To reestablish the role of KARICO.

• 한국농공학회논문집
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• 제54권2호
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• pp.37-46
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• 2012

The change of rainfall pattern and hydrologic factors due to climate change increases the occurrence probability of agricultural reservoir water shortage. Water supply assessment of reservoir is usually performed current reservoir level compared to historical water levels or the simulation of reservoir operation based on the water budget analysis. Since each reservoir has the native property for watershed, irrigation district and irrigation water requirement, it is necessary to improve the assessment methods of agricultural reservoir water capability about water resources system. This study proposed a practical methods that water supply vulnerability assessment for an agricultural reservoir based on a concept of probabilistic reliability. The vulnerability assessment of water supply is calculated from probability distribution of water demand condition and water supply condition that influences on water resources management and reservoir operations. The water supply vulnerability indices are estimated to evaluate the performance of water supply on agricultural reservoir system, and thus it is recommended a more objective method to evaluate water supply reliability.

• 한국농공학회논문집
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• 제49권3호
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• pp.3-10
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• 2007

In general method to estimate the water supplies in the large-scale basin, indirect estimation method such as unit loading factor method has been used. However, the estimated water supplies are much different to the real water supplies used in the any basin because these general methods estimate them considering water supply demands only. Especially, water supplies for irrigation are big different to the real water supplies in which the water supplies for irrigation are depend on the weather conditions such as evaporation, basin conditions such as infiltration, the reservoir operation rule for irrigation water, and distribution methods. Thus, a new estimation method is developed to estimate the real water demands which is essential factors for the effective water resources operation in the basin. This method is for estimating the water supplies and return rates based on the survey of the irrigation reservoirs and the analysis of effects to the stream flows, return flows, and water supplies for irrigation which water supplies and return rates are used in the basin water management model. The water supply usages in each subbasin are validated by comparisons between the simulated discharges from the basin water management model and the discharges measured in the control points.

• 한국농공학회지
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• 제45권6호
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• pp.96-108
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• 2003

Agricultural water occupies the largest portion of total water use in Korea, and generally researches on the development of agricultural water have been stressed on the demand of agricultural water itself. But it is unavoidable to change a policy from the development of water resources to cope with the increase of water demand to the effective management of existing water resources. Evaluation of the decrepitude of irrigation facilities and their reasonable maintenance are important for the effective supply and use of agricultural water. Therefore it is necessary to develop evaluation technique that diagnoses the current condition of irrigation canals and suggest a countermeasure to improve the found problems. 25 items in 6 classes were selected for the evaluation of irrigation canal systems, and the weighted value between the items was calculated using AHP (Analysis Hierarchy Process) method. The current condition of the irrigation facilities was evaluated from the class evaluation marks, and ranking was decided from the total marks between the projects, and finally the priority of the project for the improvement was given.

• 한국농공학회논문집
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• 제48권2호
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• pp.13-23
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• 2006

In Korea, upland irrigation generally depends on the ground water or natural rainfall since irrigation water supplied from dams is mainly used for paddy irrigation, and only limited amount of irrigation water is supplied to the upland area. For the stable security of upland irrigation water, storage level of irrigation dams was simulated by the periods. A year was divided into 4 periods considering the irrigation characteristics. Through the periodical management of storage level, water utilization efficiency in irrigation dams could be enhanced and it makes available to secure extra available water from existing dams without new development of water resources. Two study areas, Seongju and Donghwa dam, were selected for this study. Runoff from the watersheds was simulated by the modified tank model and the irrigation water to upland crops was calculated by the Penman-Monteith method. The analyzed results showed that relatively sufficient extra available water could be secured for the main upland crops in Seongju area. In case of Donghwa area, water supply to non-irrigated upland was possible in normal years but extra water was necessary in drought years such as 1998 and 2001.