In this study, it was analyzed that the effect of variation of irrigation water temperature caused by construction of the Boryeong dam to cold water damage of the paddy rice plant. The survey of irrigation water temperature and growth condition of paddy rice was carried out from May, 2001 to October, 2003 for the purpose of the analysis.
It had been selected for the consistency with the points of survey prior to construction of Boryeong dam that the survey points of Dowhadam-bridge point(D) located on upper stream area of Boryeong dam, and Hwasan-bridge point(H) and Jungjuan-village point(J) at Dongori located, respectively, on down stream area of Boryeong dam.
Intake water average temperature at Hwasan-bridge point(H) on down stream area of the dam was 1.2℃~5.0℃ lower from May to earlier July and higher from earlier August to mid September than the temperature at Dowhadam-bridge point(D) on upper stream area of the dam. This phenomenon is expected to have a positive effect on cold water damage caused by fall in atmospheric temperature after August.
The result of investigation on growing state of paddy rice plant showed non significant differences at each investigation item. It is difficult to consider that the growing state of paddy rice plant is taken negative effect of cold water damage by the low temperature of intake water, because the leaf area and the plant length of paddy rice plant at Hwasan-bridge point(H) on down stream area of the dam was larger and longer than those at Dowhadam-bridge point(D) on upper stream area of the dam. It was considered that the amount of harvest at each investigation point was influenced strongly by abnormal weather, and the decrease of production was caused by not low temperature of intake water but wrong growing method and abnormal weather.