Sediment discharge by long-term runoff in the Nakdong River watershed should be predicted for the maintenance and management of the Nakdong River newly changed by the four major river restoration project. The data establishment by the analysis of runoff and sediment discharge using the long-term watershed model is necessary to predict possible problems by incoming sediments and to prepare countermeasures for the maintenance and management. Therefore, sediment discharges by long-term runoff in the main points of the Nakdong River were calculated using SWAT(soil and water assessment tool) model and the relations and features between rainfall, runoff, and sediment discharge were analyzed in this study. As a result of sediment discharge calculation in the main points of the Nakdong River and tributaries, the sediment discharge at the outlet of the Naesung Stream was greater than the Jindong Station in the Lower Nakdong River from 1999 to 2008 except the years with low precipitation. The sediment discharge at the Nakdong River Estuary Barrage (NREB) was corresponding to 20% of the Jindong Station which is located about 80 km upstream from NREB.

The direct-runoff of South Korea's representative dams (Soyanggang, Chungju, Andong, Daecheong, and Seomjingang) and precipitation were analyzed mainly with the evenly distributed spring rainfall events across the country for the last five years. For precipitation, an increasing was presented during the period 2008-2011, but did not continue to increasing 2012. The average precipitation of the five dams displayed a similar trend. Except for Chungju and Andong Dams, the trend of runoff was similar to the one shown in the precipitation. Despite the precipitation of 2009 increased, the runoff volume decreased for Andong and Chungju Dams. In addition, Chungju Dam remarkably showed a bigger runoff volume compared to other dams. As for the Sumjingang Dam, the runoff volume was the smallest, and the difference is as great as over 15-fold when compared to other runoff values. After the result of analyzing the relation between a single runoff event and synoptic weather patterns, pattern 4 contributed to the greatest impact on this event and weather patterns. The total runoff volume of the five dams for spring rain event for the last five years that exhibited this characteristic was estimated at 5.68 billion tons(106m3). Lastly, the value of this estimation was assessed as approximately 273.1 billion KRW.

본 연구에서는 기후변화에 따른 금강유역의 미래 유출량을 산정해 댐별 용수공급 변화량을 산정하였다. GCM은 최근 국립기상연구소가 도입한 영국 기후변화 예측모델인 HadGEM2-AO를 사용하였고 새로운 온실가스 시나리오인 RCP시나리오를 금강유역내 기상관측소로 추출하였다. ArcSWAT모형을 이용해 1988년부터 2011년까지의 과거 유출모의를 수행하였으며 금강권역 내 대표 지점인 용담댐 및 대청댐 지점의 유입량과 최종 방류부의 유출량 분석값을 비교한 결과 모의치와 실측치가 각각 92.25%, 95.40%로 일치하는 것으로 나타나 모형의 적용성을 확인하였다. 또한 새로운 온실가스 시나리오 하에서의 미래 유출량을 분석한 결과 RCP4.5 시나리오 하에서 평균 47.76%, RCP8.5 시나리오 하에서 평균 36.52%가량 유출증가가 일어날 것으로 예측되었으며 특히 가을철과 겨울철에 증가율이 높았다. 유출변화에 따른 용수공급 변화를 전망하기 위하여 KModSim으로 물수지 모형을 구축하여 추가 취수량 변화를 분석하였다. 이수안전도 95% 유지조건 하에서 취수가능량을 분석한 결과, RCP4.5 시나리오 하에서 용담댐과 대청댐 각각 9.41m3/s, 24.82m3/s가 더 취수가능하며 RCP8.5 시나리오 하에서는 6.48m3/s, 21.08m3/s가 더 취수 가능한 것으로 전망되었다.

본 연구에서는 제한된 수자원 부존량을 효율적으로 사용하고 각 댐의 저류량, 수요에 대한 용수공급량 및 하천유지용수를 최대화하기 위해 댐 상 하류간의 연계운영 모형을 이용하여 연계운영 효과를 분석하고 댐과 보의 최적 연계운영을 통한 하류단의 수문학적 거동 특성 변화를 검토하여 댐운영 개선방안 도출 등 다양한 하천관리 개선 방안에 대해 연구하였다. 대상유역은 신뢰성 높은 수문자료를 획득 가능한 금강 수계 유역으로 하였으며 수문자료는 순물소모량을 감안한 '6

The purpose of this study is to estimate the impact of rainfall measurement according to the installation conditions of rain gauges: windbreak, grass mat, installation elevation or obstacle. Rain gauges were installed by the standards of Korea Meteorological Administration(KMA), and the rainfall measurement was conducted daily unit during two years(2007~2008). In conclusion, observed error of rain gauge did not affect whether windbreak was installed or not. If there is the obstacle around rain gauge, average error rate was increased about 3.3%: (2007year-2.49%, 2008year-4.10%). If rain gauge is located in a high place, average error rate was increased about 4.89%. Additionally, the observed error of rain gauge according to the wind speed has a positive correlation with obstacle and installation elevation and has a negative correlation with windbreak and has no affection with grass mat.

A accurate reservoir inflow is very important as providing information for decision making about the water balance and the flood control, as well as for dam safety. The methods to calculate the inflow were divided by the directed method to measure streamflow from upstream reservoirs and the indirected method to estimate using the correlation of reservoir water level and release. Currently, the inflow of multi-purpose dam is being calculated by the indirect method and the reservoir water level to calculate the storage capacity is being used by centimeters(cm) units. Corresponding to the storage volume of 1cm according to scale and water level of multi-purpose dam comes up to from several 10 thousand tons to several million tons. If it converts to inflow during 1 hour, and it comes to several hundred ㎥/sec(CMS). Therefore, the inflow calculated on the hourly is largely deviated along the water level changes and is occurred minus value as the case. In this research, the water level gage has been developed so that it can measure a accurate water level for the improvement for the error and derivation of inflow, even though there might be various hydrology and meteorologic considerations to analyse the water balance of reservoir. Also, it is confirmed that the error and the standard derivation of data observed by the new gage is decreased by 89,6% and 1/3 & 87% and 2/3 compared to that observed by the existing gage of Daecheong and Juam multi-purpose dam.

본 연구는 소규모 수리시설물이 장기유출에 끼치는 영향에 대해 시 공간적으로 상세히 분석하고, 분석된 결과를 토대로 장기유출 모의모형에 소규모 수리시설물의 영향을 반영할 수 있도록 구성함으로서 유역의 장기유출 모의결과의 신뢰도를 증진시키는 것이 목적이다. 따라서 본 연구에서는 대상유역의 소규모 수리시설물 현황을 파악하고 각 수리시설물별로 하천유량에 끼치는 영향을 분석한 후, 수리시설물의 영향을 고려할 수 있도록 강우-유출 모형을 구축하였다. 수리시설물에

유역의 정확한 강우-유출관계를 모의하기 위해서는 모형의 적용과 더불어 관측자료의 정확한 평가 및 검증이 병행되어야 한다. 본 연구에서는 SSARR모형을 금강유역에 적용하여 모의결과를 주요제어지점인 공주지점의 유량과 비교하였다. 분석결과 이수기시 저수위 구간에서 상당한 오차가 발생하였으며, 이에 대한 원인 분석을 위해 과거 관측유량자료(Rating Curve)의 신뢰도분석 및 유량 재관측(년)을 실시하였고, 유출성분 분석기법을 활용한 장기유출량을 산정하여