Uncertainty Analysis of SWAT Model using Monte Carlo Technique and Ensemble Flow Simulations

김필식,김선주,이재혁,지용근,Kim, Phil-Shik,Kim, Sun-Joo,Lee, Jae-Hyouk,Jee, Yong-Keun The Korean Society of Agricultural Engineers 2009 한국농공학회논문집 Vol.51 No.4

수학적 모델은 수량과 수질의 예측을 위해 현장 조사의 대안으로 사용되어지며 이러한 모델의 사용과 실측에 불확실성이 존재하게 된다. 불확실성에 대한 많은 연구들이 진행되어 왔으나 시나리오에 의한 모델링 과정에서 발생하는 불확실성에 대한 연구는 미흡한 실정이다. 본 연구에서는 산림이 농경지와 목초지로의 변화에 따른 시나리오를 설계한 후 시나리오 적용에 따른 SWAT (Soil and Water Assessment Tool) 매개변수의 불확실성을 분석하고자 하였다. 몬테카를로 기법 (Monte Carlo simulation)을 이용하여 각 매개변수별 1,000개의 난수를 발생하였으며 앙상블 유량모의 기법을 이용하여 미국 Alabama주 카하바강 상류 (50,967ha)를 대상으로 각 난수별 100개의 유량을 통해 불확실성을 분석하였다. 분석 결과 산림지역이 농경지와 목초지로 변화 되었을 때 유출량이 증가하는 것으로 분석되었으며, 임야가 목초지 보다 농경지로 변화되었을 때 유출량은 더욱 증가하는 것으로 나타났다. 각 시나리오별 SWAT 매개변수의 불확실성은 AWC (Available water capacity), CN (Curve number), GWREVAP (groundwater re-evaporation coeffeicient), REVAPMN (minimum depth of water in shallow aquifer for re-evaporation to occur)순으로 크게 나타났으며, Ksat (Saturated hydraulic conductivity)와 ESCO(Soil evaporation compensation factor)는 유출량의 변화에 큰 영향을 미치지 못하는 것으로 분석되었다. 토지피복별 산림 면적이 클 경우 불확실성이 크게 나타나 산림이 목초지와 농경지로 변함에 따라 불확실성은 감소하는 것으로 나타났다.

소규모 댐의 효과적 운영을 위한 저수관리 기법 개발

김필식,김선주,Kim Phil-Shik,Kim Sun-Joo 한국농공학회 2006 한국농공학회논문집 Vol.48 No.2

Large dams are managed with operation standard and flood forecasting systems, while small dams do not have management method generally. Shortage of water resources and natural disasters due to drought and flood raised public concerns for management of small dams. Most of small dams are irrigation dams, which need diversified water uses. However, the lack of systematic management of small dams have caused serious water wastage and increased natural disasters. Storage management method and system were developed to solve these problems in small dams. The system was applied to Seongju dam for effective management. The storage management method was established considering hydrology simulation and statistical analysis using the system. This method can bring additional available water, even in the same conditions of the water demand and the supply conditions of watershed. It can improve the flood control capacity and water utilization efficiency by' the flexible operation of storage space.

소규모 댐의 저수관리 시스템 개발

김필식,김선주,Kim, Phil-Shik,Kim, Sun-Joo 한국농공학회 2005 한국농공학회논문집 Vol.47 No.3

Ninety tow percent of over 1,800 gate controlled dams in Korea are classified as small dams. The primary purpose of these small dams is to supply irrigation water. Therefore, while large dams can store as much as 80 percent of precipitation and thus are efficient to control flood, small dams are often lack of flood control function resulting in increased susceptibility drought and flood events. The purpose of this study is to develope a storage management model for irrigation dams occupying the largest portion of small dams. The proposed Storage Management Model (STMM) can be applied to the Seongju dam for efficient management. Besides, the operation standard is capable of analyzing additional available water, considering water demand and supply conditions of watershed realistically. And the model can improve the flood control capacity and water utilization efficiency by the flexible operation of storage space. Consequently, if the small dams are managed by the proposed Storage management model, it is possible to maximize water resources securance and minimize drought and flood damages.

소규모 댐의 운영기준 및 기법 연구

김필식 ( Kim Phil-shik ),김선주 ( Kim Sun-joo ),이주용 ( Lee Joo-yong ) 한국농공학회 2005 한국농공학회 학술대회초록집 Vol.2005 No.-

The purpose of this study is to established a storage management method and operation standard for irrigation dams occupying the largest portion of small dams using storage management system. The system can be applied to seongju dam for effective management. The storage management method was established considering hydrology simulation and statistical analysis using the system. This method and operation standard are capable of analyzing additional available water, considering the water demand and supply of basin actually. It can improve the flood control capacity and water utilization efficiency by the flexible operation of storage space.

소규모 댐의 효율적 저수관리 모형 개발

김필식 ( Kim Phil Shik ),김선주 ( Kim Sun Joo ) 한국농공학회 2004 한국농공학회 학술대회초록집 Vol.2004 No.-

1. 소규모댐의 효율적인 운영을 위하여 저수관리 모형(STMM)을 개발하였다. STMM은 유역 물수지 모형, 홍수기와 평수기 저수관리 모형으로 구성되어 있으며, 현장에서 쉽게 사용할 수 있도록 Windows용 프로그램으로 개발하여 user interface를 손쉽게 구현할 수 있는 장점이 있다. 2. 유전자 알고리즘을 사용하여 평수기와 홍수기 저수관리 모형을 위한 유출 모형의 매개변수를 최적화 하였다. 3. 적용 결과 연유입량은 전국적인 가뭄이 발생한 2001년을 제외하고 평균 114,720.000m³로 60.3%의 유출율을 나타냈다. 모형의 효율성은 평균 0.78, 결정계수는 1999년을 제외하고 평균 0.8 보다 크게 나타났다. 그러나 상대오차는 일별 평균 17%, 월별, 년별 평균은 13%, 5%로 나타났다. 4. 홍수유출모형을 성주유역에 적용한 결과 홍수피해를 발생한 태풍 '루사'와 '매미'의 경우 모형의 효율성이 각 0.88, 0.87로 양호한 결과가 나타났다. 태풍 RUSA의 경우 첨두홍수량이 약 1,360m³/s로 설계홍수량 1,178m³/s 보다 약 182m³/s 가 큰 홍수량으로 댐 상 · 하류에 홍수피해가 발생하였다. 5. Modified Rigid ROM을 적용한 결과 하류부의 피해는 발생하지 않으나, 강우 500mm, 제한수위 EL. 180m부터 댐 표고 EL. 191.5m를 초과하는 것으로 나타났다. 성주댐 관리상 하계만수위를 기준으로 할 경우 강우 300mm에서도 홍수피해가 발생하였다. 따라서 이상의 결과는 댐 관리의 효율성을 최대한 중대하였다고 판단된다. 이상의 결과를 바탕으로 본 연구에서 개발된 저수관리 모형은 소규모 댐의 효율적 관리를 위해 적용이 가능하다고 판단된다. Korea has a total of 1800 dams, and 1,114 of them, 92%, are small dams, Generally, small dams have no flood control function since they are primarily designed for supplying irrigation water. Since the operation standard has not been established for small dams, unlike the large dams. In addition, the recent unusual weather patterns, changes in land uses, and the diversity of agricultural water uses have drastically increased the level of damages. The purpose of this study is to develope storage management model(STMM) for irrigation dams that occupy the largest portion of the small dams in Korea. The proposed STMM can be applied to small dams for efficient management. Besides, the operation standard is capable of analyzing additional available water, considering the water demand and the supply conditions of watershed realistically. And the model can improve the flood control capacity and water utilization efficiency by the flexible operation of storage space. Consequently, if the small dams are managed by the proposed STMM, it is possible to maximize water resources securance and minimize drought and flood damages.

현장 측정을 통한 관개용수로의 손실량 추정

이용직,김필식,김선주,지용근,주욱종,Lee, Yong-Jig,Kim, Phil-Shik,Kim, Sun-Joo,Keun, Jee-Yong,Joo, Uk-Jong 한국농공학회 2008 한국농공학회논문집 Vol.50 No.1

Water losses in irrigation canals are mainly estimated as the sum of conveyance and delivery water loss. The losses occur via the evaporation, infiltration, gate operation and water distribution processing. Recently, the study regarding these water losses are not satisfactory enough, also delivery water loss has not been mainly considered on field design. The objective of this study is to investigate and analyze the volume of water loss in irrigation canals considering condition of actual farm land. A field measurement was performed at four research sites, which are managed by Korea Rural Community & Agriculture Corporation, to evaluate conveyance and delivery water loss for 2 years. The measurement was performed by canal type, size and designed flow using the inflow-outflow method at a major points such as start and end of each canal, derivation point of canal and inlet of paddy fields. Results of this study showed that water loss ratio in lateral canals was bigger than that of main canal unlike current design standard and the loss decrease as flow increase. The total of water loss ratio including conveyance and delivery water loss in several irrigation canals ranged between 33.25 and 45.0%.

개방형 물관리 프로그램을 이용한 관개용 저수지의 거동 분석

김선주,김필식,임창영,Kim, Sun-Joo,Kim, Phil-Shik,Lim, Chang-Young 한국농공학회 2004 한국농공학회논문집 Vol.46 No.1

For optimal irrigation reservoir operation during flood and normal period, a general and systematic policy is suggested to make balance of the conflicting purposes between water conservation and flood control. We developed Open Water Management Program (OWMP) with an open architecture to deal with newly arising upgrade problems for optimal management of irrigation reservoir. And we evaluated the applicability of OWMP to estimate daily runoff from an agricultural watershed including irrigation reservoirs, and analyzed behaviour of irrigation reservoirs as irrigation water requirements considering frequency analysis of reservoir storage and frequency analysis water requirements for effective management of reservoir. When we executed OWMP with data produced from an experimental field, IHP basins, the mean relative errors of application of daily runoff and irrigation water requirement were less than 5%. We also applied OWMP to a Seongju irrigation reservoir to simulate daily runoff, storage and water requirement from 1998 to 2002, and the mean model efficiency between measured and simulated value was 0.76. Our results based on the magnitude of relative errors and model efficiency of the model simulation indicate that the OWMP can be a tool nicely adapted to the effective water management of irrigation reservoir for beneficial water use and flood disaster management.

유휴농지를 이용한 수질관리방안 연구

김형중 ( Kim Hyung-joong ),안열 ( An Yeul ),김선주 ( Kim Sun-joo ),김필식 ( Kim Phil-shik ) 한국농공학회 2005 한국농공학회 학술대회초록집 Vol.2005 No.-

Fallow paddy has been increased in disadvantageous farming condition area because of importation of foreign agricultural products, labor cost and the imbalance between farming cost and agricultural products price since 1990. The fallow paddy that has gradually increased needs to be prevented from the devastation by weed breeding for re-cultivation. In this study, two fallow paddies that manage with different water depth from the experimental field were selected for observation, and analysis of water quality, water balance and plant body change. The managed fallow paddy was more effective in water quality purification and plants growth control than non-managed fallow paddy. And the fallow paddy managed with a some degree water depth was the most effective field on weed control.

유역과 담수호를 연계한 담수호 수질관리 시스템 개발 및 적용

김선주 ( Kim Sun Joo ),김성준 ( Kim Seong Joon ),김필식 ( Kim Phil Shik ) 한국농공학회 2002 韓國農工學會誌 : 전원과 자원 Vol.44 No.6

A freshwater lake water quality management system(FLAQUM) was developed to help regional manager for the water quality of a rural basin. The integrated user interface system FLAQUM written in Visual Basic, includes three subsystems such as a database management system, basin pollutant loads simulation model using SWMM model and freshwater lake water quality simulation model using WASP5 model. Pollutant load simulation model was applied to simulate the discharge and pollutant loading from the watershed, and freshwater lake water quality model was applied to analyze the changes in water quality with respect to watershed pollutant loads, and this model could be used in planning to control watershed pollutant source for water quality management. Database management system was constructed fur all input and output data processing, and it can be used to analyze statistical characteristics using constructed data. Results are displayed both graph and text for convenience of user. The results of FLAQUM application to Boryeong freshwater lake showed that the lake was in eutrophic condition. The major contribution of pollution comes from tributary No.1 and No.4, which have a large number of livestock farms. Therefore, water quality management must be focused on appropriate management of the livestock farming in the two breanchs.

배수갑문 방류시점 및 방류량에 따른 담수호의 수질변화

김선주 ( Kim Sun Joo ),김성준 ( Kim Seong Joon ),김필식 ( Kim Phil Shik ),이창형 ( Lee Chang Hyeong ) 한국농공학회 2003 韓國農工學會誌 : 전원과 자원 Vol.45 No.1

Boryeong Seadike located at southwestern seashore of Korean peninsula completed in 1997. Sluice gate operation can be an important factor to maintain lake water quality and reduce retaining time of pollutants within lake. The lake water quality simulation model, WASPS was adopted and tested to find out proper gate operation timing and discharge amount. From the simulation of sluice gate operation, the results showed that the later the time of discharge for loosing 1 day successively to 6 days, the better the quality of water. Discharge amount showed relatively minor changes of water quality. This means that pollutants flowed into lake from watershed do not have enough time to mix up with deep water when the gate opened at early time. About 3 days delay of discharge caused the dilution effect to stabilize the lake water quality in case of Boryeong freshwater lake.