| 摘要: | 本研究透過分析相關文獻在桃園、彰化及嘉南地區的研究結果，探討一期作田間需水量、有效雨量及排水量。分析桃園、彰化及嘉南管理處的灌溉計畫書，探討各管理處間田間需水量與計畫用水量的差異，並推估其損失率。分析桃園、彰化及嘉南管理處的實際用水量，探討各管理處實際用水量與降雨量的關係。分析桃園管理處與石門管理處，以及彰化管理處與雲林管理處的數據，探討其田間需水量、計畫用水量及損失率。
以系統動力模式推估之田間需水量約為1公尺，以灌溉計畫書所呈現的數據，桃園管理處之田間需水量為1.05公尺，彰化管理處之田間需水量為1.77公尺，嘉南管理處之田間需水量為1.04公尺。根據灌溉計畫書，彰化管理處之損失率為36%，雲林管理處之損失率為50%，相較於桃園、石門及嘉南來得高。河川型灌溉不像水庫型灌溉能儲存多餘的水量，故當河川處於豐水期時，在不影響民生工業以及下游基流量時增加灌溉用水量，可減少抽取地下水，且多餘的水可再補注至地下水。
;Agricultural water demand in Taiwan accounts for about 70% of the total nation’s water consumption. First, this study explored the water requirements, effective rainfall and drainage of the first crop by analyzing the results of related literature in Taoyuan, Changhua and Chianan regions. Second, the irrigation plan of Taoyuan, Changhua and Chianan Management Offices, explored the water requirement and irrigation water consumption, and estimated the rate of conveyance loss were analyzed. Third, the actual water consumption of Taoyuan, Changhua and Chianan region were compared, and the relationship between actual water consumption and rainfall in each management region was explored. Finally, this study analyzed water requirement, irrigation water consumption and the rate of conveyance loss between Taoyuan and Shimen region, as well as that between Changhua and Yunlin region.
The crop water requirement estimated with the use of a system dynamic model is about 1 meter. According to the irrigation plan, the water requirements of Taoyuan region, Changhua region and Chianan region are 1.05, 1.77, and 1.04 meter, respectively. Furthermore, the loss rates of the Changhua region and Yunlin region are 36% and 50%, respectively, which are higher than that of Taoyuan, Shimen and Chianan region. River irrigated field is not like reservoir irrigated field where surplus water can be stored. Therefore, it is suggested that when the river is in high flow periods, without affecting the domestic and industry water use, limit the irrigation water consumption should be encouraged. Doing so, the extraction of groundwater for agriculture can be reduced, and the excess irrigation water can recharge the groundwater. |
