poster - International Conference of Agricultural Engineering

394 m. The Hai reservoir can store 2,594×10 3 tons of water. The design frequency of
droughts is 10 years, and the flood frequency is 200 years. The Bonghyun reservoir
(Standard code, 4882010045) is also located in Hai-myeon but was completed in 1998. It is
also managed and operated by the Goseong and Geoje offices of the Korean Rural
Corporation. This reservoir is also a fill dam, as the Hai reservoir. The Bonghyun reservoir is
90,823 m 3 in volume, is more than 28.4 m tall and has a length that just reaches 246 m. The
Bonghyun reservoir can store 910×10 3 tons of water, its design frequency of drought is 10
years, and its flood frequency is 200 years.
2.4 River Survey
The standard stations and periods were determined after considering the conditions that
affected the changes in flow. Five stations were downstream: 750 m, 1,260 m, 1,730 m,
4,190 m, and 5,500 m from the Bonghyeon reservoir. Three stations were downstream: 30 m,
2,000 m, and 2,810 m from the Hai reservoir. A total of eight stations were selected to
measure time-flow. The period under study was selected to compare with the irrigation
periods and the non-irrigation periods from March through September, 2011. Stream
monitoring was conducted regularly at the end of every month.
2.5 Statistical Analysis Method of River Water Quality Data
In this study, the water quality data at each station were statistically analyzed using the
partial correlation coefficients. The control variable was the flow. The water quality factor was
the independent variable. The commonly used Pearson's correlation coefficient r was the
correlation coefficient of the two variables X and Y. The values for each case (x 1 , y 1 ), (x 2 ,
y 2 ), ..., (x n , y n ) when the following equation (1) was calculated was:
: − = ∑( − ̅)( − )
,
− 1
∶ h = ∑( − ̅)
,
− 1
∶ h = ∑( − )
r =
×
(1)
− 1
Ⅲ. Results and Discussion
3.1 Analysis of the Reservoir and River
From March to September, 2011 a total of seven field surveys were conducted to measure
the water levels of the observed stream stations. The flow was calculated by measuring the
flow speed of a cross-sectional area of stream. The changes in stream flow were analyzed
according to five days of antecedent precipitation. According to TABLE 1, the low outflows of
reservoir and rainfall were dry at all times from March to May. On June 29th, a large amount
of antecedent precipitation was expected to create a large river flow. However, a stream flow
did not occur downstream of the Hai reservoir. Also, the majority of the stations at
Bonghyeon stream had little stagnant or no amount of water. It was presumed that the
ground surface was dry before the start of rainfall. Relatively, the many outflows from the
reservoir and rainfall had a flow of a fixed quantity from July to September. In TABLE 2, the
average flow of each station from May to September during the irrigation periods is relatively
larger than the average flow of each station from March to April during the non-irrigation
periods. The flows of each station are shown to have a small difference, but the irrigation
periods and the non-irrigation periods are shown to have large differences in flow.
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