• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2002.10a
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• pp.449-452
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• 2002

Characteristics of pollutant load during irrigation and non-irrigation periods was investigated for streamwater from a rural watershed. Water was sampled and discharge was measured at 5-days intervals at outlet of study area. The mean concentrations of TN and TP in an irrigation period are higher than in an non-irrigation period, while mean COD concentration in an irrigation period is lower than in a non-irrigation period. For increasing discharge during an irrigation period, TN concentration increase, TP concentration is nearly unchanged, and COD concentrations decreases.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.4
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• pp.63-72
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• 2018

The main function of an agricultural reservoir is to supply irrigation water to paddy rice fields in South Korea. Therefore, the operation of a reservoir is significantly affected by the phenology of paddy rice. For example, the early stage of irrigation season, a lot of irrigation water is required for transplanting rice. Therefore, water storage in the reservoir before irrigation season can be a key factor for sustainable irrigation, and it becomes more important under climate change situation. In this study, we analyzed the climate change impacts on reservoir storage rate at the beginning of irrigation period and simulated the reservoir storage, runoff, and irrigation water requirement under RCP scenarios. Frequency analysis was conducted with simulation results to analyze water supply probabilities of reservoirs. Water supply probability was lower in RCP 8.5 scenario than in RCP 4.5 scenario because of low precipitation in the non-irrigation period. Study reservoirs are classified into 5 groups by water supply probability. Reservoirs in group 5 showed more than 85 percentage probabilities to be filled up from half-filled condition during the non-irrigation period, whereas group 1 showed less than 5 percentages. In conclusion, reservoir capacity to catchment area ratio mainly affected water supply probability. If the ratio was high, reservoirs tended to have a low possibility to supply enough irrigation water amount.

• Magazine of the Korean Society of Agricultural Engineers
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• v.17 no.3
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• pp.3795-3814
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• 1975

The purpoes of this thesis is to study the effect of the variation of the beginning date of the suspension of irrigation and the length of intermittent suspension period of irrigation in the paddy field on the growth and yield of rice, so as the provide a critical limit of saving irrigation water and an irrigation method to prevent drough damage in rice cultivation. In this experiment, the rice variety adopted was NONGRIM No.29. There were seven main test plot, each test plot having a different beginning date of the suspension of irrigation. A main test plot was susdivided into five small test plots, each having a different length of the suspension period of irrigation. The results obtained in this experiment are summarized as follows: 1. The number of tillers is controlled by the treatment of the suspension of irrigation, its beginning date being early of late. The reductive effects of beginning dates of suspension upon the number of tillers. investigated on July 30, are about 84% for the treatment suspended on July 8, 87% on July 12, and 92% on July 19, respectively, in comparison with the standard plot. However. the suspenion treatments after the foregoing dates does not affect the control of their numbers. On the other hand, the lengths of intermittent suspension periods influence highly on the number of tillers to be restrained considerably, the decrease ratio ranging from 91% to 80% Both treatments on dates and periods are so intermingled that the restraining effects of suspension periods become greater as the dates of its beginning are earlier. 2. The elongation of plant hieghts also restrained considerably by the longer periods and earlier dates of suspension treatments of irrigation. Especially, the effects of the lengths of suspension periods become more serious. 3. Heading dates are delayed by two to five days through the suspension treatments of irrigation. However, the heading stage ends almost on the same day without relation to the differences between the irrigation suspension treatments. In the test plot where the suspension date of irrigation comes after the young panicle forming stage, the heading stage ends one or two days later than in the standard test plot. 4. Both culm lengths and panicle lengths show significant differences in their values, i.e., their lengths are shorter, as the begining dates of irrigation suspension are earlier and the suspension periods are longer. 5. The earlier the beginning date and the longer the period of irrigation suspension, the less is the number of panicles per hill in comparison with the standard plot. 6. The earlier the beginning date and the longer the period of irrigation suspension, the higher is the significant difference in the number of kernels per panicle in comparison with that in the standard test plot, i.e., the less is the number of kernels per panicle. 7. The earlier the beginning date and the longer the period of irrigation suspension, the lighter are the weights of rough rice and straws per hill in comparison with those in the standard plot.

• Applied Biological Chemistry
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• v.43 no.4
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• pp.285-290
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• 2000

This research was carried out to investigate the runoff pattern of nutrients by rainfall from the paddy field located at the southwest of Korea. Effective rainfalls were 17.0 and 21.2 mm for irrigation and non-irrigation period, respectively. The first runoff in paddy field was 6.3-33.7 mm (average=12.9 mm) and 5.9-12.5 mm (9.2 mm) for irrigation and non-irrigation period, respectively. And runoff ratio was 0.59-1.36 and 0.57-0.86 for irrigation and non-irrigation period, respectively. During irrigation and non-irrigation period, the outflow increased significantly with the precipitation. Pattern of precipitation-runoff differed between irrigation and non-irrigation period, as affected by precipitation intensity, hydrological condition, and cropping. There existed a linear relationship between the runoff loading of N and P and precipitation. During the irrigation and non-irrigation period, runoff loadings of N and P were not significantly different. However, there was significant difference in case of total suspended solids.

• KCID journal
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• v.16 no.1
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• pp.51-58
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• 2009

• KCID journal
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• v.16 no.2
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• pp.43-50
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• 2009

• KCID journal
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• v.13 no.2
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• pp.274-282
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• 2006

The objective of this study was to develop a hydrologic simulation model to predict daily streamflow from a small agricultural watershed considering irrigation return flow. The proposed IREFLOW(Irrigation REturn FLOW) model consists of hillslope runoff model, irrigation scheme drainage model, and irrigation return flow model, and simulates daily streamflow from an irrigated watershed. Two small watersheds were selected for monitoring of hydrological components and evaluating the model application. The relative error (RE) between observed and simulated daily streamflow were 2.9% and 6.4%, respectively, on two small agricultural watersheds (Baran and Gicheon) for the calibration period. The values of RE in daliy streamflow for the validation period were 6.0% for the Baran watershed, and 2.8% for the Gicheon watershed.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.2
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• pp.54-60
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• 2007

This study was conducted to investigate growth characteristics of irrigation period of greenary mats focused on management as a material to apply on rooftop. Using Sedum kamtschaticum, Sedum takesimense, Sedum reflexum, Sedum album and Sedum burrito greenary mats were made. The irrigation periods were every 3 days, 7 days, and 10 days after made each greenary mats.1. All treatments on survival ratio of 5 Sedum species were over 96%. Especially, new individuals were emerged from naturally detached leaves. 2. Growth of S. kamtschaticum, S. takesimense, S. reflexum were good on 7 day irrigation treatment. 3. The highest covering ratio of S. burrito was 3 day irrigation treatment, and the hightest of the others were 7 day irrigation treatment. Considerations for species selection, mixture, ratio and management were obtained from this study.

• Journal of The Korean Society of Agricultural Engineers
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• v.63 no.3
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• pp.59-73
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• 2021

The purpose of this study is to investigate transition of pumping technology, irrigation water requirement, and unit area drainage discharge at the Pumping station-based Irrigation Associations (PIAs) in South Korea during Japanese colonial period (1910-1945). The PIAs established pumping stations and embankments along rivers for the purpose of irrigation, drainage and flood prevention until the mid-1920s. From the late 1920s after major river improvement projects, newly established PIAs did not include the flood prevention in their purpose of establishment. The design criteria of the irrigation and drainage projects, such as irrigation water requirements, design rainfall, and allowable ponding duration were decided according to the circumstances of PIAs. The gross irrigation water requirement of paddy fields increased from the 1920s to the 1940s, and reached the level of 0.0020 m³/s/ha (19 mm/d) in the 1940s for the fairly good irrigation status in the drought. The great floods of 1930, 1933, and 1934 triggered the increase in drainage discharge in the late 1930s, leading to the unit area drainage discharge of 0.9-2.6 m³/s/km² for natural drainage and 0.3-1.1 m³/s/km² for pump drainage. Therefore, several PIAs near the major rivers could avoid repetitive floods damage.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.185-185
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• 2023

Agricultural water demand is considered as the major sector of water withdrawal due to irrigation. The majority part of the global agricultural field depends on various irrigation techniques. Therefore, a timely and sufficient supply of water is the most important requirement for agriculture. Irrigation is implemented in different ways in various land surface models, it can be modeled empirically based on observed irrigation rates or by calculating water supply and demand. Certain models can also calculate the irrigation demand as per the soil water deficit. In these implementations, irrigation is typically applied uniformly over the irrigated land regardless of crop types or irrigation techniques. Whereas, the latest version of Community Land Model (CLM) in the Community Terrestrial Systems Model (CTSM) uses a global distribution map of irrigation with 64 crop functional types (CFTs) to simulate the irrigation water demand. It can estimate irrigation water withdrawal from different sources and the amount or the areas irrigated with different irrigation techniques. Hence, we set up the model for the simulation period of 16 years from 2000 to 2015 to analyze the global irrigation demand at a spatial resolution of 1.9° × 2.5°. The simulated irrigation water demand is evaluated with the available observation data from FAO AQUASTAT database at the country scale. With the evaluated model, this study aims to suggest new sustainable scenarios for the ratios of irrigation water withdrawal, high depending on the withdrawal sources e.g. surface water and groundwater. With such scenarios, the CFT maps are considered as the determining factor for selecting the areas where the crop pattern can be altered for a sustainable irrigation water management depending on the available withdrawal sources. Overall, our study demonstrate that the scenarios for the future sustainable water resources management in terms of irrigation water withdrawal from the both the surface water and groundwater sources may overcome the excessive stress on exploiting the groundwater in major river basins globally.