• 한국농공학회논문집
• /
• 제59권4호
• /
• pp.17-26
• /
• 2017

In this study, EPANET model which is using on the pipe network analysis was applied to Haenam irrigation district has provided irrigation water by pipeline system about 1,125ha and then have built pipe network to study area and supply performance evaluation of existing structure was analyzed by SPA (Single Period Analysis) in EPANET. As model results of simulation average ratio of maximum supply quantity/irrigation water requirements(base demand) was analyzed by 2.63. It means also that was analyzed as being capable of ensuring the water supply capacity. It was provided the necessary information for the maintenance facility through analyzed hydraulic behaviors in the pipeline inside such as flow velocities, pressures and hydraulic grade lines. It was satisfied with the allowable design criteria that was compared analyzed results with presented allowable design standards at agricultural production infra improvement project planning and design (Pipeline design standard). In order to analyze efficiency promotions of irrigation water, using Extended Period Simulation it was compared supply quantity with irrigation water requirements while pumps set operating pattern in 24 hours, then efficiency promotions of irrigation water was determined through analyzed oversupply water quantity and occurrence time by branch lines. According to results for oversupply quantity in Haenam district by time and end of branch lines efficiency promotions of irrigation water was suggested from 0.33 % to 37.59 %. To draw reasonable operating rules for water use and through this research, it is expected to be helpful for efficient water use and operational management of agricultural pipeline system to the current agricultural irrigation.

• 한국수자원학회논문집
• /
• 제44권3호
• /
• pp.169-177
• /
• 2011

기후변화가 우리나라의 논 관개요구량에 미치는 영향을 분석하였다. 기상연구소의 SRES A2 시나리오에 대한 고해상도 ($27{\times}27\;km$) 기후 자료와 기준년도 (1971~2000)의 관측 기상자료를 이용하였다. 기상연구소가 전지구모형 ECHO-G 예측자료를 MM5 모형으로 역학적으로 상세화한 결과를 이용하였다. 논 관개요구량의 공간적인 변화를 분석하기 위하여 GIS 기법을 이용하였다. 연구결과는 벼 생육기간의 평균기온은 기준년도에 비해 $1.5^{\circ}C$ (2020s), $3.3^{\circ}C$ (2050s) 및 $5.3^{\circ}C$ (2080s) 상승할 것으로 예측되었다. 벼 생육기간의 강우량은 0.1% (2020s), 4.9% (2050s) 및 19.3% (2080s) 증가할 것으로 예측되었다. 영농 형태와 논 면적이 변하지 않는다고 가정하면 우리나라 논의 총 관개용수량은 2.8% (2020s), 4.9% (2050s) 및 4.5% (2080s) 증가할 것으로 예측되었다. 본 연구의 결과는 총 관개용수량이 다소 감소할 것으로 예측한 다른 연구결과와는 상반된 결과를 나타내었으며, 그 주원인은 사용된 GCM에 따른 기후 예측치의 차이에서 온 것으로 판단된다. 관개용수량의 시공간적 변동성이 큰 것으로 나타났으며 이는 앞으로 관개계획과 물 관리에서 고려되어야 할 것이다.

• 한국농공학회:학술대회논문집
• /
• 한국농공학회 2001년도 학술발표회 발표논문집
• /
• pp.441-444
• /
• 2001

This study describes the characteristics of concentrations of pollutants such as tolal nitrogen(T-N), total phosphrous(T-P), and chemical oxgen demand(COD) at paddy areas during 2-year dry irrigation periods. Most of pollutants concentrations in drainage water are lower than those in irrigation water after early July due to large uptake of pollutants by rice crop and denitrification. For drainage water, the concentrations of pollutants are constant irrespective of discharges and the average T-N/T-P ratios water range from 14 to 44, suggesting that phosphrous is limiting.

• 한국농공학회지
• /
• 제30권1호
• /
• pp.50-62
• /
• 1988

This study refers to the development of a hydrologic model simulating daily inflow and release rates for irrigation reservoirs. A daily - based model is needed for adequate operation of an irrigation reservoir sufficing the water demand for paddy fields which is closely related to meteorological conditions. Inflow rates to a reservoir need to be accurately described, which may be simulated using a hydrologic model from daily rainfall data. And the objective of this paper is to develop, test, and apply a hydrologic model for daily runoff simmulation. A well - known tank model was selected and modified to simulate daily inflow rates. The model parameters were calibrated using observed runoff data from twelve watersheds, Relationships between the parameters and the watershed characteristics were derived by a multiple regression analysis. The simulation results were in agreement with the data. The inflow model was found to simulate low flow conditions more accurately than high flow conditions, which may be adequate for water resources utilization.

• 한국농공학회지
• /
• 제18권3호
• /
• pp.4195-4205
• /
• 1976

The purpose of this study is to evaluate the existing methods for calculating or estimating the consumptive use (Evaportranspiration) of any agricutural development project area. In determing the consumptive use water in the project area, there will require the best way for estimating irrigation requirement. Many methods for computing the evaportranspiration have been used, each of them with its merits and demerits at home and abroad. Some of these methods are listed as follows: 1.The Penman's formula 2.The B1aney-Criddle method 3.The Munson P.E. Index method 4.The Atmometer method 5.The Texas Water Rights Commission (TWRC) method 6.The Jensen-Haise method 7.The Christiasen method Therefore, the authors will introduce the more widely used method for calculating Consumptive Use by G.H. Hargreaves. The formula is expressed in the form Ep= K·d·T (1.0-0.01·Hn) Hn=1.0+0.4H+0.005H2. This method was adopted for the first time to determine the Irrigation requirements of Ogseo Comprehensive Agricultual Development project (Benefited area:100,500ha) in Korea. This method is presented in somewhat greater detail than the others. Formula is given for the computation of evaportranspiration (with various levels of data availability) Sampel computation of irrigation requirements for Ogseo irrigation project is included. The results and applied materials are summarized as follows. 1. In calculating the Hargreaves formula, the mean temperature relative, humidity, length of day, and percentage of sunshine from three stations of Iri, Jeonju, and Gunsan were used. 2. Monthly evaporation values were calculated by using the formula. 3. Meteological data from the three stations records for the ten years (1963∼1972) were used. 4. The annual irrigation requirements is 1,186mm per hectare, but the case to consider effective rainfall amount takes the annual irrigation demand being 700mm per hectare.

• 한국농공학회논문집
• /
• 제62권6호
• /
• pp.73-83
• /
• 2020

Agricultural drought is a natural phenomenon that is difficult to observe and quantitatively express, and agricultural water use is high and usage patterns are diverse, so even if there is a lack of rainfall. The frequency and severity of agricultural drought are increased during the irrigation period where the demand for agricultural water is generated, and reasonable and efficient management of agricultural water for stable water supply is required. As one method to solve the water shortage of agricultural water in an unstructured method, it is necessary to analyze the appropriate supply amount and supply method through simulation from the intake works to the canals organization and paddy field. In this study, irrigation efficiency was analyzed for irrigation systems from April to September over the past three years from the Musu Reservoir located in Jincheon-gun, Chungcheongbuk-do and Pungjeon Reservoir located in Seosan-si, Chungcheongnam-do. SWMM (Storm Water Management Model) was used to collect agricultural water, and irrigation efficiency analysis was conducted using adequacy indicators, and water supply vulnerability. The results of the agricultural water distribution simulation, irrigation efficiency and water supply vulnerability assessment are thought to help the overall understanding of the agricultural water supply and the efficient water management through preliminary analysis of the methods of agricultural water supply in case of drought events.

• 한국농공학회지
• /
• 제27권4호
• /
• pp.31-41
• /
• 1985

This paper compares the estimated total construction and maintenance costs for irrigation canals in six irrigation districts near Pyongtaek. Three conventional canal types were considered: concrete bench flumes, concrete-lined canals, and earth canals. The total expenses for each type were grouped to four catagories: the net construction, land acquisition, maintenance, and other expenses. The construction costs included the assumed costs for conveyance losses from each type of canals. The results from this study support earlier studies that the bench flumes are economically feasible. Initially cheaper conveyance systems like concrete-lined and earth canals demand 'higher maintenance costs and thus, their total expenses are summed to exceed those for the bench flumes within a few years following the construction. Banch flumes are economically justifiable for the main canals of the studying districts. Sensitivity analyses were executed to evaluate the relative importance of each expense to the total cost. The analyses show that total expenses very significantly with the change of the following costs: cost for conveyance losses, net construction, maintenance, and land acquisition, in that order However, other expenses contribute little if not at all to the total. The results indicate that bench flumes should be adopted as main canal structures for most irrigation districts in the Republic.

• 한국농공학회논문집
• /
• 제56권5호
• /
• pp.1-9
• /
• 2014

The DIROM (Daily Irrigation Reservoir Operation Model) was modified to estimate amounts of water release from reservoirs, considering customary irrigation water management practices, such as water supply for puddling and transplanting paddy rice from seeding beds and mid-season drainage. The applicability of the modified model was investigated by simulating amounts of water release from three study reservoirs: Hwamae, Ogi, and Doya Reservoirs. In terms of annual amounts of water release, the relative errors between the observed and simulated values in 2012 and 2013 ranged -26.20 % to 10.28 % and 4.90 % to 30.06 %, respectively; in case of reservoir water levels, the RMSE values ranged 0.45 m to 1.34 m and 0.40 m to 1.27 m, respectively. Also, it was revealed that the model provided better simulation results for monthly water releases than the original model. In addition, the model presented better performance in simulating 10-day amounts of water release from April to June. However, the model had still significant errors in the simulation results from July to September because the reservoirs were practically operated to adapt to water management circumstances. Finally, it is concluded that the modified DIROM can estimate the amounts of water release from reservoirs, reflecting irrigation water management customs in paddy-field districts. To achieve higher prediction accuracy of the model, it is necessary to incorporate practical reservoir operation rules into the model.

• 한국농공학회논문집
• /
• 제56권5호
• /
• pp.77-87
• /
• 2014

The impacts of climate change on upland crops is great significance for water resource planning, estimating crop water demand and irrigation scheduling. The objective of this study is to predict upland crop evapotranspiration, effective rainfall and net irrigation requirement for upland under climate change, and changes in the temporal trends in South Korea. The changes in consumptive use and net irrigation requirement in the six upland crops, such as Soybeans, Maize, Potatoes, Red Peppers, Chinese Cabbage (spring and fall) were determined based on the soil moisture model using historical meteorological data and climate change data from the representative concentration pathway (RCP) scenarios. The results of this study showed that the average annual upland crop evapotranspiration and net irrigation requirement during the growing period for upland crops would increase persistently in the future, and were projected to increase more in RCP 8.5 than those in RCP 4.5 scenario, while effective rainfall decreased. This study is significant, as it provides baseline information on future plan of water resources management for upland crops related to climate variability and change.

• 한국농공학회논문집
• /
• 제61권1호
• /
• pp.121-130
• /
• 2019

The purpose of this study is to determine the amount of irrigation water for upland crop growth based on the 30 year of historical rainfall data and the water management guidelines as a reference. Five regions and ten crops were selected by their cultivation size. The changes of soil moisture contents were calculated using daily mean rainfall and irrigation demand. This study assumed that crops are irrigated when the soil moisture contents fell below of the field capacity for more than 5 days, which is the drought condition defined by RDA. The maximum irrigation water requirements was 167.2 mm for chinese cabbage during the growing season, which was followed by corn (112.0 mm), daikon (102.3 mm), spinach (66.1 mm), lettuce (56.7 mm), pepper (46.5 mm), potato (33.9 mm), sweet tomato (27.4 mm), peanut (11.5 mm) and bean (10.3 mm), The results of this study could contribute to providing valuable data to determine the capacity of irrigation facilities and to establish the emergency operation plans under extreme unfavorable weather condition (heat wave, etc.) for crop growth.