다중목적 최적화기 법을 이용한 SWAT 모형 수분매개변수의 자동보정

김학관,강문성,박승우,최지용,양희정,Kim, Hak-Kwan,Kang, Moon-Seong,Park, Seung-Woo,Choi, Ji-Yong,Yang, Hee-Jeong 한국농공학회 2009 한국농공학회논문집 Vol.51 No.1

The objective of this paper was to evaluate the auto-calibration with multi-objective optimization method to calibrate the parameters of the Soil and Water Assessment Tool (SWAT) model. The model was calibrated and validated by using nine years (1996-2004) of measured data for the 384-ha Baran reservoir subwatershed located in central Korea. Multi-objective optimization was performed for sixteen parameters related to runoff. The parameters were modified by the replacement or addition of an absolute change. The root mean square error (RMSE), relative mean absolute error (RMAE), Nash-Sutcliffe efficiency index (EI), determination coefficient ($R^2$) were used to evaluate the results of calibration and validation. The statistics of RMSE, RMAE, EI, and $R^2$ were 4.66 mm/day, 0.53 mm/day 0.86, and 0.89 for the calibration period and 3.98 mm/day, 0.51 mm/day, 0.83, and 0.84 for the validation period respectively. The statistical parameters indicated that the model provided a reasonable estimation of the runoff at the study watershed. This result was illustrated with a multi-objective optimization for the flow at an observation site within the Baran reservoir watershed.

강우유출수 관리시설의 설계를 위한 강우사상 특성 분석

김학관,지현서,장선숙,Kim, Hak Kwan,Ji, Hyun Seo,Jang, Sun Sook 한국농공학회 2017 한국농공학회논문집 Vol.59 No.6

The objective of this study is to investigate whether the daily rainfall depth derived from daily data represents the event rainfall depth derived from hourly data. For analysis, the 85th, 90th, and 95th percentile daily rainfall depths were first computed using daily rainfall data (1986~2015) collected at 63 weather stations. In addition, the storm event was separated by the interevent time definition (IETD) of 6, 12, 18, and 24 hr using hourly rainfall data. Based on the separated storm events, the 85th, 90th, and 95th percentile event rainfall depths were calculated and compared with the using hourly rainfall data with the 85th, 90th, and 95th percentile daily rainfall depths. The event rainfall depths computed using the IETD were greater than the daily rainfall depths. The difference between the event rainfall depth and the daily rainfall depth affects the design and size of the facility for controlling the stormwater. Therefore, the designer and policy decision-maker in designing the stormwater best management practices need to take into account the difference generated by the difference of the used rainfall data and the selected IETD.

하천에서의 영양물질 관리를 위한 총질소 환경기준 설정에 관한 연구

김학관,정한석,배승종,Kim, Hak Kwan,Jeong, Han,Bae, Seung Jong 한국농공학회 2015 한국농공학회논문집 Vol.57 No.3

The objective of this study is to suggest the water quality criteria of total nitrogen in order to efficiently manage the nutrient pollution in the stream. For this, correlations between water quality parameters were examined using the water quality data collected from the water quality monitoring network in the four rivers between 2003 and 2012. T-N showed positive correlations with T-P (0.636), COD (0.577), BOD (0.574), TOC (0.440), and SS (0.367). The statistical analysis including percentile analysis for the T-N and T-P concentrations was utilized to develop the water quality criteria of T-N. The feasibility of the suggested water quality criteria was evaluated by calculating the achievement rate to water quality target at the representative points in mid-watershed, then the draft water quality standard of T-N was suggested. The suggested water quality standard of T-N in the stream may be used to efficiently control the nutrient pollution in the public water body.

농경지 불투수면 변화에 따른 유역 수문 영향 분석

김학관,이은정,박승우,강문성,Kim, Hak-Kwan,Lee, Eun-Jeong,Park, Seung-Woo,Kang, Moon-Seong 한국농공학회 2009 한국농공학회논문집 Vol.51 No.6

The Soil and Water Assessment Tool (SWAT) model was used in this study to evaluate the hydrologic impacts by the impervious surface change in the farm region. The model was calibrated and validated by using four years (1999-2002) of measured data for the Gyeongancheon watershed in Korea. The simulation results agreed well with observed values during the calibration and validation periods. Land use scenarios including various changes of the plastic film house area in the farm region were applied to assess their effects on watershed hydrology. The results indicated that the surface direct (5.6%~14.0%) and total runoff (0.8%~1.5%) increased, but the groundwater discharge (10.7%~27.7%) and evapotranspiration (1.5%~3.3%) decreased as the plastic film house area (5.7%~12.4%) increased.

HEC-HMS와 HEC-RAS를 이용한 농촌 저지대 침수해석

김학관,강문성,송인홍,황순호,박지훈,송정헌,김지혜,Kim, Hak-Kwan,Kang, Moon-Seong,Song, In-Hong,Hwang, Soon-Ho,Park, Ji-Hoon,Song, Jung-Hun,Kim, Ji-Hye 한국농공학회 2012 한국농공학회논문집 Vol.54 No.2

The objective of this study is to analyze the flood inundation in a low-lying rural area. The study watershed selected for this study includes the Il-Pae and Ahn-Gok watersheds. It is located in the Namyangju, Korea and encompasses $3.64km^2$. A major flood event that occurred in July 2011 was chosen as the case for the flood inundation analysis. The Hydrologic Engineering Center's Hydrologic Modeling System (HEC-HMS) and River Analysis System (HEC-RAS) were used to simulate flood runoff and water surface elevation at each cross-section, respectively. The watershed topographic, soil, and land use data were processed using the GIS (Geographic Information System) tool for the models. The contribution to the total flood volume was estimated based on the results simulated by HEC-HMS and HEC-RAS. The results showed that the overflow discharge from the Il-Pae stream constituted 80% of the total flood volume. The contributions of rainfall falling directly on the inundation area and overflow discharge from the Ahn-Gok stream were 15 % and 5 %, respectively. The simulation results in different levee scenarios for the Ahn-Gok stream were also compared. The results indicated that the levee could reduce the flood volume a little bit.

장래 기후변화와 토지이용 변화에 따른 농촌소유역의 수문 영향 분석

김학관,강문성,이은정,박승우,Kim, Hak-Kwan,Kang, Moon-Seong,Lee, Eun-Jeong,Park, Seung-Woo 한국농공학회 2011 한국농공학회논문집 Vol.53 No.6

The objective of this study is to evaluate the hydrologic impacts of climate and land use changes in a rural small watershed. HadCM3 (Hadley Centre Coupled Model, ver.3) A2 scenario and LARS-WG (Long Ashton Research Station - Weather Generator) were used to generate future climatic data. Future land use data were also generated by the CA-Markov (Cellular Automata-Markov) method. The Soil and Water Assessment Tool (SWAT) model was used to evaluate hydrologic impacts. The SWAT model was calibrated and validated with stream flow measured at the Baran watershed in Korea. The SWAT model simulation results agreed well with observed values during the calibration and validation periods. In this study, hydrologic impacts were analyzed according to three scenarios: future climate change (Scenario I), future land use change (Scenario II), and both future climate and land use changes (Scenario III). For Scenario I, the comparison results between a 30-year baseline period (1997~2004) and a future 30-year period (2011~2040) indicated that the total runoff, surface runoff, lateral subsurface runoff, groundwater discharge, and evapotranspiration increased as precipitation and temperature for the future 30-year period increased. The monthly variation analysis results showed that the monthly runoff for all months except September increased compared to the baseline period. For Scenario II, both the total and surface runoff increased as the built-up area, including the impervious surface, increased, while the groundwater discharge and evapotranspiration decreased. The monthly variation analysis results indicated that the total runoff increased in the summer season, when the precipitation was concentrated. In Scenario III, the results showed a similar trend to that of Scenario II. The monthly runoff for all months except October increased compared to the baseline period.

불투수면 변화에 따른 유역 수문 영향 분석

김학관 ( Hak Kwan Kim ),이은정 ( Eun Jung Lee ),박승우 ( Seung Woo Park ) 한국농공학회 2009 한국농공학회 학술대회초록집 Vol.2009 No.-

본 연구에서는 SWAT 모형을 이용하여 불투수면 변화에 따른 유역 수문 영향을 분석하였다. 경안천유역의 경안 수위표 상류유역을 대상유역으로 선정하여 유역의 수문 자료를 수집하였으며, 대상유역의 위성영상 및 항공사진을 수집하고 원격탐사기법 및 지리정보시스템 이용하여 불투수면을 고려한 토지피복도 및 수치지형자료 등을 구축하여 SWAT 모형의 적용성을 평가하였다. 1999년부터 2002년까지의 대상유역의 자료를 이용하여 유출량에 대하여 모형의 보정과 검정을 수행하였으며, 그 결과 모형이 적용성이 있는 것으로 평가되었다. 토지이용변화를 예측하여 장래 유역의 불투수면 변화 시나리오를 작성하고 구축된 모형을 이용하여 시나리오에 따른 유역 수문 영향을 분석하였다. 불투수율이 9.5%인 2002년 토지이용도를 이용해 모의한 결과에 비해 불투수율이 17.9%인 2020년의 토지이용도 시나리오를 적용한 경우는 지표 유출량은 13.7%, 직접 유출량은 3.6%, 총 유출량은 0.4% 증가하는 것으로 나타났으며, 측방 유출량은 4.3%, 지하수 유출은 22.3%, 증발산량은 2.1% 감소하는 것으로 나타났다.

농업용수 재이용을 위한 논벼 생육시험

김학관 ( Kim Hak-kwan ),박승우 ( Park Seung Woo ),김상민 ( Kim Sang-min ) 한국농공학회 2003 한국농공학회 학술대회초록집 Vol.2003 No.-

This paper presents a recent finding from the progressed research efforts on the application for wastewater reclamation and reuse for agricultural uses. Reclaimed effluents from the Suwon municipal sewer treatment plant has been used to irrigate paddy rice at experimental plots. Three levels of reclamation treatments, filtration, disinfection, and the both, and one treatment to apply heavily polluted stream flow are compared to the control which uses groundwater for irrigation. The rice growth indicated by plant height and tiller number, and the yields were compared statistically among the five treatments. The results showed that the rice yields from polluted stream were greatest, and the control showed the lowest yields. And the first year experiment indicated that the agricultural reuse is promising.

토양수분변화를 고려한 관개블럭에서의 유출량 추정모형의 개발

김학관 ( Kim Hak Kwan ),박승우 ( Park Seung Woo ),임상준 ( Im Sang Jun ) 한국농공학회 2007 한국농공학회 학술대회초록집 Vol.2007 No.-

The objective of this study was to develop a runoff simulation model from a paddy block considering on soil moisture. The model simulates daily flooding depth, evapotranspiration, soil moisture, deep percolation, surface runoff from irrigated paddies using meteorological, irrigation, soil and agricultural management data. The model was applied to examine the feasibility of the developed model for the irrigation period of paddy block in study site. The study site, which is located in Hwaseong-si, Gyeonggi-do, Korea was selected to monitor hydrologic and field data. The runoff from paddy block were simulated by the data of 1999 and 2001. The simulation results were in good agreement with the data as determination coefficient (R²) of 0.60~0.74, root mean square error (RMSE) of 7.42~8.92 and effficiency index (EI) of 0.25~0.34.

하수처리수의 논 관개용수 재이용이 벼의 수확량에 미치는 영향

김학관 ( Kim Hak Kwan ),김상민 ( Kim Sang Min ),박승우 ( Park Seung Woo ) 한국농공학회 2004 한국농공학회 학술대회초록집 Vol.2004 No.-

본 연구에서는 수원시 환경사업소 하수처리장을 선정하여 인근 논에 시험포장을 조성하고, 각 처리구에 따른 벼 재배시험을 실시하였다. 그 결과를 바탕으로 관개수 처리구별 벼의 수확량에 대한 분산분석을 실시하여 처리구별 유의성을 고찰함으로써, 하수처리수의 논 관개용수 재이용이 수확량에 미치는 영향을 평가하였다. 본 연구의 결과를 요약하면 다음과 같다. 1. 2002년과 2003년의 관개수 처리구별 벼의 수확량을 조사분석한 결과 지하수로 관개한 처리구(TP#1)가 수확량이 상대적으로 작게 나타났다. 2. 최소유의차 검정을 위한 분산분석결과 지하수로 관개한 대조구(TP#1)에 대하여 5% 유의수준에서 유의차가 있는 것으로 나타났다. 3. 최소유의차 검정결과 2002년에는 황구지천 하천관개수(TP#2)와 모래여과를 실시한 관개수 (TP#4)처리구는 대조구인 지하수 관개수(TP#1) 처리구와 유의차가 있었고, 하수처리수를 이용한 관개수(TP#3), 모래여과 후 UV소독처리를 한 관개수(TP#5)의 처리구는 유의차가 없는 것으로 나타났으며, 2003년에는 대조구인 지하수 관개수(TP#1)에 대해 모두 유의차가 인정되었다. 4. Duncan의 다중검정결과 황구지천 하천관개수(TP#2)나 하수처리수를 이용한 관개수(TP#3). 모래여과를 실시한 관개수(TP#4) 그리고 모래여과 후 UV소독처리를 한 관개수(TP#5)의 처리구에서 큰 값을 나타내거나 대부분 유의차가 없는 것으로 나타났으며, 상대적으로 지하수를 관개수로 사용한 처리구(TP#1)의 경우는 작은 값을 보여 다른 처리구와 유의성이 인정되었다. 이상의 결과에서와 같이, 하수처리수의 관개용수로의 재이용은 수확량에 큰 장애가 없는 것으로 나타났다. This paper presents the wastewater reuse effects on rice yields. Reclaimed effluents from the Suwon Municipal Sewer Treatment Plant used to irrigate paddy rice at experimental plots. Three levels of reclamation treatments, filtration, disinfection, and the both, and one treatment to apply heavily polluted stream flow are compared to the control which uses groundwater for irrigation. Five treatments were applied to the experimental plots from 2002 to 2003. As a result of statistical comparison for rice yields, only control treatment, ground water, showed lower yields than the other treatments. The least significant difference (LSD) showed the control treatment was significant at the 5% level, and the Duncan's multiple range test showed that 5%and 1% levels were significant. In terms of rice yield, there was no negative effect when reclaimed wastewater was applied.