• 한국환경과학회지
• /
• 제20권8호
• /
• pp.977-986
• /
• 2011

This study analyzed the characteristics of stormwater runoff in the orchard areas and quantitatively estimated effluence of nonpoint source pollutants for the volume of runoff. Two target areas under vine cultivation were each $2,000m^2$ and $1,800m^2$, located in Gyeongju City. Since grape was the only crop on the target area, the characteristics of stormwater runoff at vineyard could be evaluated independently. A total of 51 rainfall events in the vineyard area during two years(2008-2009) was surveyed, and 19 of them became stormwater runoff, with rainfall ranging 16.5 - 79.7 mm and antecedent dry period of 1-13 days. The pollutant runoff loads by volume of stormwater runoff showed BOD ranging 19.5 - 45.3% in 30% of runoff volume. The average pollution discharge rate was 32.4%, indicating small first flush effect of BOD. The range of SS concentrations was 5 - 52.0% in 10% of runoff volume, showing the average 28.7% of discharge rate, about 3 times more than rainfall effluent. TOC and TN appeared to be similar to the results of BOD, the average discharge rate of 30.9% and 30.6% for TOC and TN, respectively, for 30% of stormwater runoff volume. Average discharge rate of COD and TP in the same runoff volume was 35.1% and 36%, respectively, showing comparatively high discharge ratio. As the targeted vineyard area was permeable land, the pollution load ratio against rainfall-runoff volume appeared to be 1:1, implying no strong first flush effect for all the survey items.

• 한국수자원학회논문집
• /
• 제56권12호
• /
• pp.905-918
• /
• 2023

본 연구에서는 목감천 유역에서 투수성포장(PP)과 빗물저류조(RB)의 설치에 의한 유출량 저감 성능 분석 및 유역 내 설치 우선순위를 결정했다. PP와 RB의 설치를 통한 최대 유출 저감 성능 도출을 위해 최적 설계인자를 결정했고, 최적 설계인자를 반영한 PP와 RB의 우수 유출 저감 성능을 비교했다. 유출량의 시계열 변화로부터 첨두유출량 발생 전에는 PP가, 첨두유출량 발생 후에는 RB가 유출량 저감에 더 우수한 성능을 나타냈다. PP와 RB의 설치에 따른 소유역 별 총 유출량, 첨두유출량 저감 성능을 비교한 결과, PP의 경우 유역면적이 큰 소유역에서 RB보다 더 높은 우수 유출저감 성능을 나타냈고 RB는 불투수면적 비율이 높은 지역에서 더 높은 성능을 나타냈다. PP와 RB의 우수 유출 저감 성능 평가 결과를 통해 목감천유역 내 두 시설의 설치 우선 순위를 결정했다. 그 결과, PP와 RB 모두 유역면적, 불투수면적 비율이 높은 소유역에서 높은 우선 순위가 나타났다. 또한 우수 유출 저감 성능 평가 순위와 유역특성 간 상관관계를 비교한 결과, 상위 25%의 우수 유출 저감 성능을 나타낸 소유역에서는 불투수면적외에도 유역의 형상 인자와 높은 상관관계를 보였다. 이를 통해 기존 도심 지역에 우수유출저감시설 설치 우선 순위 결정 시 불투수면적 비율과 함께 유역의 형상 인자를 함께 고려해야 함을 알 수 있다.

• 한국환경과학회지
• /
• 제24권12호
• /
• pp.1649-1656
• /
• 2015

Jeju Island is the highest rain-prone area in Korea that possesses affluent water resources, but future climate changes are predicted to further increase vulnerabilities as resultant of increasing of extreme events and creating spatial-temporal imbalance in water resources. Therefore, this study aimed to provide basic information to establish a proper water resources management plan by evaluating the effects of climate change on water resources using climate change scenario. Direct runoff ratio for 15 years (2000~2014) was analyzed to be 11~32% (average of 23%), and average direct runoff ratio for the next 86 years (2015~2100) was found as 28%, showing an increase of about 22% compared to the present average direct runoff ratio (23%). To assess the effects of climate change on long-term runoff, monthly runoff variation of future Gangjeong watershed was analyzed by dividing three time periods as follows: Present (2000~2030), Future 1 (2031~2070) and Future 2 (2071~2100). The estimated results showed that average monthly runoff increases in the future and the highest runoff is shown by Future 2. Extreme values has been expected to occur more frequently in the future as compared to the present.

• 한국농공학회지
• /
• 제32권E호
• /
• pp.33-46
• /
• 1990

Abstract Over 700/0 of the rural land area in Korea is mountainous and small watersheds provide most of the water resources for agricutural use. To provide an appropriate tool for the agricultural water resource development project, SNUA2, a mathematical model for simulating the physical processes governing the precipitation-runoff relationships and predicting the storm and long-term runoff quantities from the small mountainous watersheds was developed. The hydrological characteristics of small mountainous watersheds were reviewed to select appropriate theories for the simulation of the runoff processes, and a deterministic and distributed model was developed. In this, subsurface flows are routed by solving Richard's two dimensional equation, the dynamics of soil moisture contents are simulated by the consideration of phenological factors of canopy plants and surface flows are routed by solving the kinematic wave theory by numerical analysis. As a result of an application test of the model to the Sanglim watershed, peak flow rates of storm runoff were over-estimated by up to 184.2%. The occurence time of peak flow and total runoff volume of storm runoffs simulated were consistent with observed values and the annual runoff volumes were simulated in the error range of less than 5.8%.

• 한국농공학회논문집
• /
• 제49권3호
• /
• pp.21-31
• /
• 2007

This study is aimed at the development of a runoff forecasting model by using the Fuzzy inference system and Neural Network model to solve the uncertainties occurring in the process of rainfall-runoff modeling and improve the modeling accuracy of the stream runoff forecasting. The Neuro-Fuzzy (NF) model were used in this study. The NF model, recently received a great deal of attention, improve the existing Neural Networks by the aid of the Fuzzy theory applied to each node. The study area is the downstreams of Naeseung-chun. Therefore, time-dependent data was obtained from the Wolpo water level gauging station. 11 and 2 out of total 13 flood events were selected for the training and testing set of model respectively. The schematic diagram method and the statistical analysis are conducted to evaluate the feasibility of rainfall-runoff modeling. The model accuracy was rapidly decreased as the forecasting time became longer. The NF model can give accurate runoff forecasts up to 4 hours ahead in standard above the Determination coefficient $(R^2)$ 0.7. In the comparison of the runoff forecasting using the NF and TANK models, characteristics of peak runoff in the TANK model was higher than ones in the NF models, but peak values of hydrograph in the NF models were similar.

• 한국물환경학회지
• /
• 제23권4호
• /
• pp.527-534
• /
• 2007

To operate scientifical and integrated management of water resources, it needs to identify clearly the quantitative variation and moving pathway of water resources in a basin. Moreover, it needs to also estimate more precisely the amount of runoff generating from the precipitation. Thus, in this study, to carry out more reliable hydrologic analyses, the runoff characteristics according to detailed runoff components and water balance in a basin are analyzed. As a result of yearly water balance analyses, during the period of drought year, the loss is bigger than that of 6-year mean loss and the return flow of groundwater is the most dominant component of runoff. During the period of flood year, the loss is smaller about 4% than that of 6-year mean loss and the subsurface water is the most dominant component of runoff. The loss due to the interception and evapotranspiration for 6-year mean loss is about 53% of the total rainfall, the mean runoff ratio is about 27% and the baseflow is about 22%.

• 한국수자원학회논문집
• /
• 제39권11호
• /
• pp.905-914
• /
• 2006

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($'03{\sim}'05$년)을 실시하였고, 유출성분 분석기법을 활용한 장기유출량을 산정하여 제어지점의 수리특성을 명확히 분석하고자 하였다. 분석결과 SSARR 모의결과 및 유출성분분석에 의한 장기유출량 산정결과는 재관측된 유량과 근사한 것으로 분석되었으나, 기존의 관측유량은 지점의 공간적 특성에 기인한 수리학적 영향으로 인해 평 갈수기시 약 $10{\sim}20%$ 과대 산정된 것으로 분석되어 이에 관한 보정 및 지속적인 모니터링이 필요하다.

• 한국농공학회논문집
• /
• 제52권1호
• /
• pp.1-11
• /
• 2010

Generation and transportation of runoff and pollutant loads within watershed generated eutrophication at Daecheong reservoir. To improve water quality at Daecheong reservoir, the best management practices should be developed and applied at upper watersheds for water quality improvement at downstream areas. In this study, two small watersheds of upper Daecheong reservoir were selected. The Long-Term Hydrologic Impact Assessment (L-THIA) model has been widely used for the estimation of the direct runoff worldwide. To apply the L-THIA ArcView GIS model was evaluated for direct runoff and water quality estimation at small watershed. And the Web-based Hydrograph Analysis Tool (WHAT) was used for direct runoff separating from total flow. As a result, the $R^2$ (Coefficient of determination) value and Nash-Sutcliffe coefficient value for direct runoff comparison at An-nae watershed were 0.81 and 0.71, respectively. And the $R^2$ value and Nash-Sutcliffe coefficient value at Wol-oe were 0.95 and 0.93. The $R^2$ value of BOD, TOC, T-N and T-P at An-nae watershed were BOD 0.94, TOC 0.81, T-N 0.94 and T-P 0.89. And the $R^2$ value of BOD, TOC, T-N and T-P at Wol-oe watershed were BOD 0.80, TOC 0.93, T-N 0.86 and T-P 0.65. The result that estimated pollutant loadings using the L-THIA ArcView GIS model reflected well the measured pollutant loadings except for T-P in Wol-oe watershed. With L-THIA ArcView GIS model, the direct runoff and non-point pollutant (NPS) loadings in the watershed could be analyzed through simple input data such as daily rainfall, land uses, and hydrologic soil group.

• 한국수자원학회논문집
• /
• 제54권1호
• /
• pp.61-69
• /
• 2021

본 연구에서는 스마트시티 하천관리를 효율적으로 수행하기 위하여 웹상에서 홍수분석 모델을 연계하고 입력 및 출력 정보를 데이터베이스화하여 정보를 제공하는 연계플랫폼을 개발하였다. 연계플랫폼에서는 스마트시티 내 홍수분석을 하기 위하여 유역유출 분석 모델, 하천흐름 분석 모델 그리고 도시유출 분석 모델을 적용하였다. 본 플랫폼에서는 적용한 모델을 통해 스마트시티 내 발생할 수 있는 도시유출에 대하여 단계적으로 접근함으로써 더욱 신뢰성 있는 결과를 획득할 수 있다. 또한, 데이터 수집, 입력데이터 생성 및 결과 데이터 저장과 같은 모든 분석 과정이 웹상에서 진행되기 때문에 특수 장비나 도구 없이 웹에 접근할 수 있는 환경만 구축된다면 분석 수행과 결과 조회가 가능하다. 이를 통하여 스마트시티 관리자들은 효율적인 하천 및 도시 관리가 가능하고, 더불어 도시유출에 대한 교육용 자료로도 활용될 수 있을 것으로 기대된다.

• 한국물환경학회지
• /
• 제29권5호
• /
• pp.681-690
• /
• 2013

Watershed models have been increasingly used to support an integrated management of land and water, non-point source pollutants, and implement total daily maximum load policy. However, these models demand a great amount of input data, process parameters, a proper calibration, and sometimes result in significant uncertainty in the simulation results. For this reason, uncertainty analysis is necessary to minimize the risk in the use of the models for an important decision making. The objectives of this study were to evaluate three different uncertainty analysis algorithms (SUFI-2: Sequential Uncertainty Fitting-Ver.2, GLUE: Generalized Likelihood Uncertainty Estimation, ParaSol: Parameter Solution) that used to analyze the sensitivity of the SWAT(Soil and Water Assessment Tool) parameters and auto-calibration in a watershed, evaluate the uncertainties on the simulations of runoff and sediment load, and suggest alternatives to reduce the uncertainty. The results confirmed that the parameters which are most sensitive to runoff and sediment simulations were consistent in three algorithms although the order of importance is slightly different. In addition, there was no significant difference in the performance of auto-calibration results for runoff simulations. On the other hand, sediment calibration results showed less modeling efficiency compared to runoff simulations, which is probably due to the lack of measurement data. It is obvious that the parameter uncertainty in the sediment simulation is much grater than that in the runoff simulation. To decrease the uncertainty of SWAT simulations, it is recommended to estimate feasible ranges of model parameters, and obtain sufficient and reliable measurement data for the study site.