홍성구 Hong Seonggu

DOI: JKWST Vol.51(No.2) 1-6, 2009

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홍우용 Hong Woo Yong , 박민지 Park Min-ji , 박종윤 Park Jong Yoon , 하림 Ha Rim , 박근애 Park Geun Ae , 김성준 Kim Seong Joon

DOI: JKWST Vol.51(No.2) 7-14, 2009

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The purpose of this study is to identify how much the MODIS NDVI (Normalized Difference Vegetation Index) can explain the forest soil moisture simulated from SWAT (Soil and Water Assessment Tool) model. For ChungjuDam watershed (6,661.3 ㎢) which covers 82.2 % of forest, the SWAT model was calibrated for four years (2003-2006) at two locations of the watershed using daily streamflow data and was verified for three years (2000-2002) with average Nash and Sutcliffe model efficiencies of 0.69 and 0.75 respectively. For the period from March to June, the average spatial correlation between 16 days composite MODIS NDVI and the corresponding SWAT forest soil moisture was 0.90. The two variables averaged for each data set during that period showed an inverse relation with the average coefficient of determination of 0.55.

조재필 Cho Jaepil , 전종안 Chun Jong Ahn , 모스타기미사이드 Mostaghimi Saied

DOI: JKWST Vol.51(No.2) 15-27, 2009

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서동욱 Seo Dong Uk , 김현태 Kim Hyeon Tae , 장병욱 Chang Pyoung Wuck , 이상훈 Lee Sang Hun

DOI: JKWST Vol.51(No.2) 29-34, 2009

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A series of laboratory model tests and numerical analysis is performed to analyze characteristics of desalination and to predict a period of desalination for subsurface saturated soil in Saemanguem reclaimed area. The results show that quantity of desalination is small as salinity of water is increased. On the contrary, quantity of desalination is increased as salinity of soil is high. In order to decrease the salinity to 10 % of initial salinity of soil at depth of 2 m, it takes 11 years to desalinate the soil 50 m away from drainage ditch. For soil at depth of 1.5 m only 1 year to desalinate the soil near drainage ditch. Also, water head of 80 cm is required to desalinate to 10 % of initial salinity for 60 cm thick soil. Because the following results is based upon the Saemangeum soil, an application of this result for another field will be cautious. More research will be required on this matter.

정상옥 Chung Sang-ok

DOI: JKWST Vol.51(No.2) 35-41, 2009

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The impacts of climate change on paddy irrigation requirements for Nakdong river basin in Korea have been analyzed. The HadCM3 model outputs for SRES A2 and B2 scenarios and International Water Management Institute 10’x10’ pixels observed data were used with kriging method. Maps showing the predicted spatial variations of changes in climate parameters and paddy irrigation requirements have been produced using the GIS. The results showed that the average growing season temperature was projected to increase by 2.2°C (2050s A2), 0.0°C (2050s B2), 3.7°C (2080s A2) and 2.9°C (2080s B2) from the baseline (1961-1990) value of 21°C. The average growing season rainfall was projected to increase by 15.2% (2050s A2), 24.2% (2050s B2), 41.4% (2080s A2) and 16.7% (2080s B2) from the baseline value of 900 mm. Average volumetric irrigation demands were projected to decrease by 3.7% (2050s A2), 7.0% (2050s B2), 10.2% (2080s A2) and 1.4% (2080s B2) from the baseline value of 1.25×10⁹ ㎥. These results can be used for the agricultural water resources development planning in the Nakdong river basin for the future.

김태곤 Kim Taegon , 이정재 Lee Jeong-jae

DOI: JKWST Vol.51(No.2) 43-49, 2009

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Many researcher uses simulation techniques for understanding the phenomenon and expecting the response. Simulation techniques have many advantages which is less time-consuming, easy to control constraints, and cheaper than experimental study. However Researches usually are not good at programming the model, it's hard to implement simulation model using computer language. They use spreadsheet program like Microsoft excel^TM Although a spreadsheet program is good for modeling, it's cumbersome to describe expressions which consist of not variable name but location indicator. This study suggests the program which helps researcher developing model using graphical interface and variable name. For verifying usability, the model which is implemented by developed modeler were compared with by spreadsheet program.

오광영 Oh Kwang Young , 김진수 Kim Jin Soo , 오승영 Oh Seung Young

DOI: JKWST Vol.51(No.2) 51-57, 2009

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The purpose of this study was to investigate characteristics of behavior of nutrients such as TN (Total nitrogen), TDN (Total dissolved nitrogen), TP (Total phosphorus) TDP (Total dissolved phosphorous) in runoff water from a nonpoint source dominated watershed (6.67 ㎢). Regular and intensive flow measurement and water sampling were taken during two years (February 2002 to January 2004) in the Ingyeong River, a tributary of the Han River. The mean concentrations of nutrients during rainy days were significantly (p < 0.05) higher than those during dry days. The mean TDN/TN ratio in rainy days (95%) is almost identical to that in dry days (96%), but mean TDP/TP ratio in rainy days (24%) significantly decreased compared with that in dry days (66%), suggesting that dominant form of TP is shifted from dissolved form to particulate form. Accordingly, the measures (.eg. filter strips, cover crops) to reduce soil erosion for fallow upland in the rainy season should be taken to control particulate phosphorous.

황현섭 Hwang Hyun-seob , 이인복 Lee In-bok , 신명호 Shin Myeong-ho , 홍세운 Hong Se-woon , 서일환 Seo Il-hwan , 유재인 Yoo Jae-in , Bitog Jessie. P. , 권경석 Kwon Kyeong-seok , 김용희 Kim Yong-hee

DOI: JKWST Vol.51(No.2) 59-67, 2009

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A study on fugitive dusts was conducted at Saemangeum reclaimed land located in Gim-je area. The monitoring result on the fugitive and suspended dust was significantly affected by the farming activities(harvesting and land cultivation) and vehicles passing nearby the measuring points. The concentration of the fugitive dust generated from the reclaimed land was reduced remarkably by the effect of halophyte present on the ground and the tide embankment. Comparing the data collected in 2006 and 2007, the concentrations of TSP and PM10 decreased by 47.4% and 29.5%, respectively. After harvesting operations at paddy field, TSP increased by 22% while PM10 increased by 54%. The concentration of a Cl- which is a representative ion of sea-salt decreased to about 35% in 2007 compared with 2006. This represents that the inside area change and plant covering rate affected on the decrease of fugitive dust. The correlation analysis for the compounds of topsoil at each measuring point shows that near the coastline is more comparable. The canopy of halophyte in the source area also increased which reduced the fugitive dust remarkably. The dust distribution measured by dust spectrometer at the same point shows that most particles are 0.5㎛ to 2um size but not greater than 5㎛.