Optimal size estimation of water storage tank for upland crops

This study estimates the amount of water utilized during the growing season of the cultivated crops and drought frequency analysis is applied to the estimated water requirement. In order to analyze the amount of rainwater flowing into the storage tank to be used by each crop was estimated through the return period of drought frequency analysis and the appropriate capacity of the storage tank was examined. Using the hydrological operation model for the water resources system program, the required quantity of water by crop was calculated using the crop coefficient. In order to analyze the drought frequency according to the growing season of each crop, a suitable distribution is selected between Gumbel, Pearson type 3, generalized extreme value, generalized logistic, generalized Pareto, and generalized normal through the statistical hydrological analysis and the goodness of fitness tests. Based on the selected distribution type, the series of designed water requirement were extracted according to the growing season of each cultivated crop. The shortage of cultivated crops was calculated using the results of the required quantity of water and drought frequency analysis. Estimation of the sufficiency ratio about how much rainwater can be reused using the water demand for the field crops and the height of potential reservoirs, and the optimum rainwater storage capacity of field crops was suggested according to the demand. In this study, it is possible to know the amount of water shortage for cultivated crops. Therefore, if water shortages occur due to extreme drought in the future, it can be provided as basic data necessary for the preparation of drought and it is expected to determine the capacity of rainwater storage tank construction.