本研究選定研究區域為桃園大圳二支線灌區；探討季長期氣象預報於灌區營運決策的應用與經濟價值分析。以2015年水情乾旱為例進行模擬。並於桃園大圳二支線灌區建立灌區與埤塘水平衡模式；研究流程分為資料輸入端(大竹測站實際雨量資料、季長期預報資料與氣象合成器繁衍雨量資料)；模擬端(利用灌區與埤塘水平衡模式推估灌區缺水量等水文資訊)；策略端(利用灌區缺水量量化季預報應用於灌區之經濟價值)。 本研究並探討預報不同準確度情境下，建立季長期預報資訊結合埤塘浚深方案架構，量化季預報應用於灌區用水之經濟價值。於各策略所模擬成本皆顯示不使用預報策略成本皆高於使用預報策略，顯示使用預報之優勢。當預報準確度提升，本研究量化之預報價值也跟著上升。 另外利用季預報資訊結合埤塘浚深，提出四種策略:一、有預報且執行埤塘浚深；二、有預報且不執行埤塘浚深；三、無預報且執行埤塘浚深；四、有預報且不執行埤塘浚深。量化浚深對於提升之灌區效益。探討於乾旱時期，哪種方案為最佳策略選擇；埤塘浚深模擬則分為三個方案。一、於二支線無埤塘灌區增設埤塘；二、於埤塘效益指數低於平均灌區浚深埤塘；三、利用灌區缺水天數與缺水量作為優先挑選埤塘浚深依據。本研究期望建立之架構與預報價值資訊可以提供灌區營運者，當面臨乾旱水情時，能依據預報經濟價值，選擇為灌區帶來較佳效益的策略。 ;The research area selected in this study is the irrigation area of the second branch of Taoyuan channel; the application of seasonal forecast information combined with the evaluation of the economic value of agricultural water in the first phase of the Taoyuan channel Second Branch Irrigation District. Taking the water drought in 2015 as an example, the simulation was carried out. The deep simulation is divided into three schemes. 1. Adding a pond in the Irrigation District of the Second Branch; 2. The benefit index is lower than the average irrigation area in the deep pond; 3. Using the number of days of water shortage in the irrigation area and the water shortage as the basis for selecting the pond excavation; When it is dry, which option is the best strategy choice. Combined with the forecast of the season, there are four strategies in tandem: one, there is a forecast and the implementation of the Pond excavation depth; second, there is a forecast and the implementation of the Pond excavation depth; third, no forecast and implementation of the Pond excavation depth; fourth, there is a forecast and no Perform Pond excavation deep. Use the cost of each strategy to quantify the value of the forecast, and quantify the depth to improve the efficiency of the irrigation district. And to explore the perfect forecast, and with different accuracy forecast scenarios, with different Pond excavation deep plan, to estimate the forecast value. And the cost results simulated by each strategy can be obtained without using the forecast strategy. The cost is higher than the use forecast strategy, showing the advantage of using the forecast. And the simulation predicts that when the accuracy of the forecast increases, the value of the forecast quantified in this study will also increase. The strategic framework established in this study can provide irrigation district operators. When faced with arid water conditions, what strategies can be chosen to bring better benefits to the irrigation districts.