建立水旱作混植區之地表水與地下水聯合灌溉管理模式

台灣在農業灌溉用水除了使用渠道灌溉供水外，農民會另以抽取地下水來補足渠道水不足之情形，然農業用水於作物生長階段較多，抽取量也隨之增加，因此本研究於台灣中部彰化莿仔埤圳的三條圳幹線重劃區，利用紀錄表及訪談調查灌區取水情形，針對農民灌溉經驗方式及農田灌溉機制，以系統動力學模式建立一套可自動推估地下抽水及估算灌溉用水量模式，此模式可依循作物生長階段之灌溉基準點及灌溉需水點，自動判斷抽水時間及抽取量，達目標水深後即停止，可減少農民個人操作習慣不同而衍生抽水不一之情形。本研究透過模式得到良好的農業用水模擬結果，探討灌區用水情形，進一步提升農業用水之水源分配效率。本研究利用2016年二期作水文條件，如降雨、蒸發量、作物生長時程等水文資料，透過灌溉用水模式進行不同水旱作面積比例情形下作物需水量變化模擬，探討灌溉用水情形，後續使農業灌溉用水及地下水方便管理，結果顯示作物種植比例及作物生長階段顯著影響灌溉用水情形，當水稻面積增加，灌溉需水量增加，若水稻面積增加渠道供水量並無增加時，田間地下抽水量相對提高。本研究採用渠道供水量優先模式之分析結果，若上游灌區水源得以經模型控制，部份由地下水提供，則可相對減少其對於渠道水源之取用量；換言之，以此模式可達成調配渠道水量予下游灌區使用，並以地下水源為上游灌區進行補充灌溉，可使各個輪區渡過枯旱缺水時期。本研究延伸探討地下水抽水情形與地下水位之影響，由於2015年二期作降雨時空分布較一期作多且均勻，補注量亦較多，因此灌區2015年一、二期作地下抽水情形與地下水位之影響，二期作之抽水情形尚在安全抽取範圍內。

關鍵字

系統動力模式；水旱作混植；灌溉系統；地下水抽取

並列摘要

Taiwan's agricultural water expected use irrigation channel to irrigate crops, farmers also choose pumped groundwater to fill a vacancy in the irrigation channel. A large amount of agricultural water will be used in crop growth stage. The study area is located in the midst of Taiwan Changhua Cizaipijun aqueduct. Taking into account the farmers' irrigation experience and in-field irrigation operating, this study applies system dynamic model to establish an irrigation water management model for mixed paddy rice and upland crops fields. This model can follow the crop growth stage of the irrigation basic point and irrigation demand point, automatically determine the pumping time and rate, reach the target water depth then stop. This model can automatically identify the groundwater pumping time and the rate. It can reduce the possible human errors of the farmers during the operation of pumping. Moreover, this study, through the model to simulate a good agricultural water results, was able to explore the irrigation water use situation and further to enhance the water distribution efficiency of agricultural water use. In this study, the hydrological data such as rainfall, evaporation, crop growth time and so on. Using the irrigation water management model to simulate the change of crop water demand with different area paddy rice and upland crops area ratio. To explore the situation of irrigation water, so that agricultural irrigation water and groundwater for easy to management. In general, the application of channel water and/or groundwater irrigation depends on the crop planting condition, such as crops planting ratio and the growth stage of crops. The results shown that the ratio of crops cultivation and the growing stage of crops significantly affect the irrigation water capacity. When the area of paddy rice cultivation increase, the need of irrigation water capacity will increase. However, if the water supply of canal do not increase but the area of paddy rice cultivation increase, the groundwater pumping in the paddy field will raise. According to the results of analysis in channel water supply priority model, if the upstream irrigation area can be modeled and partly provided by groundwater, it can reduce the amount of water supply taken from channel water. In other words, the allocation of canal water can be adjusted to the downstream area, and the upstream area water demand can obtain additional supplement from groundwater. To make each round block can pass through the drought period. This study discusses the influence of groundwater pumping and groundwater level. In the second rice crop period has received frequent rainfall with spatial and temporal uniformity is directly proportional to the recharge of groundwater and pumping situation. Then, the groundwater recharge is also increased. By comparing the pumping rate and groundwater level for the first and the second rice crop period in 2015, the second rice crop period pumping is more reasonable than the first rice crop period

並列關鍵字

System dynamic model ； Mixed Crop ； Irrigation system ； Groundwater Pumping

國際替代計量

建立水旱作混植區之地表水與地下水聯合灌溉管理模式

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