• KCID journal
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• v.13 no.2
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• pp.262-273
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• 2006

The Soil and Water Assessment Tool (SWAT) model has been widely used in hydrology and sediment simulation worldwide. In most cases, the SWAT model is first calibrated with adjustments in model parameters, and then the validation is performed. However, very little study regarding the effects on SWAT estimation of subwatershed delineation was performed. Thus, the SWAT model was applied to the Doam-dam watershed with various threshold values in subwatershed delineation in this study to examine the effects on the number of subwatershed delineated on SWAT estimation. It was found the flow effect of subwatershed delineation is negligible. However there were huge variations in SWAT estimated sediment, T-N, and T-P values with the use of various threshold value in watershed delineation. Sometimes these variations due to watershed delineation are beyond the effects of parameter adjustment in model calibration and validation. The SWAT is a semi-distributed modeling system, thus, the subwatershed characteristics are assumed to be the same for all Hydrologic Response Unit (HRU) within that subwatershed. This assumption leads to variations in the SWAT estimated sediment and nutrient output values. Therefore, it is strongly recommended the SWAT users need to use the HUR specific slope length and slope value in model runs, instead of using the slope and the corresponding slope length of the subawatershed to exclude the effects of the number of subwatershed delineated on the SWAT estimation.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.299-302
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• 2003

This study aims to apply and compare flood routing methods for irrigation reservoirs. In this research, three methods, which are the storage indication method(SIM), the mass curve method(MCM), the frog method(FM) were adopted and applied to two storm events of July $9{\sim}10\;and\;22{\sim}23$ of Donghwa-dam and its watershed located on Jangsoo-gun, Chunnam province. As the application results MCM showed the highest value at peak overflow and goodness-of-fit to the observed value, although the others also had similar value with the observed one. In analyzing lag time of peak between inflow and overflow MCM and SIM showed 7 hours, while FM showed 6 hours for the first storm event, and all three methods showed 3 hours for the second event.

• Journal of Korean Society on Water Environment
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• v.20 no.5
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• pp.473-479
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• 2004

A sedimentation basin (SB) at the inlet of an irrigation reservoir which was constructed using an auxiliary dam was monitored to evaluate its pollutant removal efficiency. Water sampling at three points, i.e., inflow stream, upstream and downstream of the reservoir, were taken 5 times before and after the construction of the SB in 1999 and 2003, respectively. No significant water quality variations in inflow stream were observed during these periods. The COD, T-N, T-P and SS removal efficiencies were 38, 24, 35 and 49%, respectively. The results indicated that those removal efficiencies significantly increased during the rainy season and COD removal efficiency, especially, was higher than others studies. The scale of SB in this study was rational as aspects of pollutant removal efficiency and hydraulic detention time. And it is recommended that SB, at inlet of an reservoir, should be constructed as completely separated structure from reservoir water body and having SAR Index from 0.7% to 1.0%.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2002.10a
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• pp.373-376
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• 2002

It is reported that Korea is a county of water shortage. The government make plans to construct dam to cope with this problem. But, it become difficult to construct dam, because of public opinion of residents and objection of environmentalist. In the sense, the government set up new policy of demand-management which means water saving. It is known that the efficiency of agricultural water is so poor that the first target to save water is focussed on agricultural water. In the study, the function of agricultural water was evaluated and it is found that it is not a waste, but a good ability on eco-system by return flow.

• KCID journal
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• v.8 no.1
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• pp.80-87
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• 2001

The purpose of this study is to determine flow rate for operation system of the Borland fishlock. The fish ladder is usually constructed at the diversion weir crossing the river. But, at the place of the high dam, the fish ladder is very difficult to keep

• KCID journal
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• v.1 no.1
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• pp.32-43
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• 1994

In order to control the flood effectively, Ministry of Construction has implemented the tele - metering(TM) facilities on the Young-san River Basin which has the area of 3,471$km^2$. Rural Development Corporation which is responsible for the es

• KCID journal
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• v.10 no.1
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• pp.44-52
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• 2003

This study surveyed farming condition and the effects of nonpoint source pollution loading by cultivating in the flood control area of multi-purpose dams. According to the multi-purpose dam management regulation, cultivation can be permitted between norma

• KCID journal
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• v.10 no.1
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• pp.62-72
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• 2003

Tideland reclamation has been known to begin in 13th century in the eastern coast of Ganghwa Island during the Mongolian Invasion in Korea. Traditionally, the tidal reclamation projects have been developed in the coastal with nearly flat inter-tidal zone

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.40-48
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• 2008

The Waimea Basin is located on the northern tip of the South Island of New Zealand. It is a highly productive area with intense water use with multi-stakeholder interest in water. Irrigation from the underground aquifers here makes up the largest portion of used water; however the same aquifers are also the key urban and industrial sources of water. The Waimea/Wairoa Rivers are the main sources of recharge to the underlying aquifers and also feed the costal springs that highly valued by the community and iwi. Due to the location of the main rivers and springs close to the urban centre the water resource system here has high community and aesthetic values. Recent enhanced hydrological modelling work has shown the water resources in this area to be over allocated by 22% for a 1:10 year drought security for maintaining a minimalistic flow of 250 l/s in the lower Waimea River. The current irrigated land area is about 3700 hectares with an additional potential for irrigation of 1500 hectares. Further pressures are also coming on-line with significant population growth in the region. Recent droughts have resulted in significant water use cutbacks and the threat of seawater intrusion in the coastal margins. The Waimea Water Augmentation Committee (WWAC) initiated a three year stage 1 feasibility study in 2004/2005 into the viability of water storage in the upper parts of the catchment for enhancing water availability and its security of supply for consumptive, environmental, community and aesthetic benefits downstream. The project also sought to future proof water supply needs for the Waimea Plains and the surrounding areas for a 50 - 100 year planning horizon. The broad range stage 1 investigation programme has identified the Upper Lee Catchment as being suitable for a storage structure to provide the needs identified and also a possibility for some small scale hydro electricity generation as well. The stage 2 detailed feasibility investigations that are underway now (2007/2008), and to be completed in two years is to provide all details for progressing with the next stage of obtaining necessary permits for construction and commissioning a suitable dam.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.2
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• pp.147-156
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• 2012

가뭄강도와 지속기간을 고려하여 관개구역을 몇 개의 관개블록으로 나누어 순차적으로 제한하여 급수함으로써 관개용수를 절약하고 관개기간을 연장하여 가뭄을 극복하는 윤환관개모형 (RISS)을 제안한 바 있다. 이 RISS는 작물생육기별 관개저수지 저수율별 급수구역과 제한 급수율을 제시함으로써 가뭄기간에 저수지 운영자가 언제, 얼마나 제한하여 급수할 것인지 제시해주는 모형으로 전북 남원군 동화댐의 물 관리시스템 자동화 프로그램에 2004년 설치하여 운용되도록 하였다. 이 연구에서는 2004년부터 2009년까지 동화 댐 저수위 관측기록과 급수실적을 분석하여 RISS의 절수효과를 평가하고자 하였다. 그러나 실제로는 동화댐의 물 관리시스템 자동화 프로그램이 계획대로 운용되지 않고 있었다. 따라서 이 RISS의 절수효과와 효용성을 입증하여 계획대로 자동화시스템을 유용하게 활용하도록 하기 위해서 급수실적 및 저수위 관측기록과 RISS로 모의 발생한 저수위 결과를 비교 평가하였다. 모의발생 평가결과 가뭄이 극심했던 2007년에는 3.8백만 $m^3$을 절수하여 관개기간을 23일 연장하고 2009년에는 3.3백만 $m^3$을 절수하여 관개기간을 13일 연장하여 가뭄이 극심한 해에는 RISS 모형의 효용성이 크다는 것을 알 수 있었다.