不同灌溉制度對地下水補注之影響評估

Assessing the groundwater recharge under various irrigation schemes

林子喬(Zih-Ciao Lin)

指導教授 ： 陳世楷

國立臺北科技大學/工程學院/土木與防災研究所/碩士(2013年)

https://doi.org/10.6841/NTUT.2013.00183

摘要

本研究以目前國際間積極推廣之水稻強化栽培法:(The System of Rice Intensification，SRI)所擬定之節水灌溉原則，探討其在台灣施行時，可能造成地下水補注量減少之衝擊。三維地下水模式(FEMWATER)因具備可變邊界條件(Variable boundary condition)模擬功能，可以應用在模擬分析不同灌溉用水制度，湛水深度隨時間改變時，對地下水入滲補注之影響。本研究以彰化田中實驗田之現地資料，包括土壤分層，入滲率及田區土壤水分分佈等資料，驗證建立水田淺層地下水補注模式。根據本土水田環境特性及SRI所需改變之灌溉操作方式，評估氣候條件與農業用水操作等情境改變下，田間湛水深度隨時間改變對應之入滲率變化情形，量化評估其對淺層地下水補注功能，並與我國現行之灌溉方式(續灌及輪灌)進行比較。結果顯示使用續灌湛水深度6cm平均入滲率為最高，達4.57 mm/day；輪灌次之，5天灌溉期距之入滲率為4.42mm/day、7天灌溉期距則為4.38mm/day；SRI法之平均入滲率最低，3及5天灌溉期距分別為4.12mm/day與4.09mm/day。以5天灌溉期距之SRI法為例，其補注量分別較續灌、5天期距之輪灌減少達12%及9%。研究結果可提供相關單位作為研擬整體地下水水資源經營管理調適方案之基礎。

關鍵字

水稻強化栽培法 ； 三維地下水模式 ； 灌溉制度 ； 地下水補注 ； 入滲率

並列摘要

The System of Rice Intensification (SRI) was developed as a set of insights and practices used in growing irrigated rice. Based on the water-saving irrigation practice of SRI, impacts of the new methodology on the reducing of groundwater recharge were assessed in Taiwan. The three-dimensional groundwater model (FEMWATER) with the variable boundary conditions analog functions, was applied in simulating groundwater recharge under different irrigation schemes with variable ponded water depth. In-situ measurements including soil layers, infiltration rate, and soil moisture distribution of Ten-Chung experimental field (located in Chung-Hwa county, central Taiwan) were used in model validation. According to local climatic and environmental characteristics associated with SRI methodology, the change of infiltration rate was evaluated compared with the traditional irrigation schemes, including continuous irrigation and rotational irrigation scheme. The results showed that average infiltration rates in growing season for continuous irrigation with 6cm ponded water depth, rotational scheme with 5-day irrigation interval, rotational scheme with 7-day irrigation interval, SRI methodology with 3-day irrigation interval, and SRI methodology with 5-day irrigation interval were 4.57 mm/day, 4.42mm/day, 4.38mm/day, 4.12mm/day, and 4.09mm/day, respectively. The groundwater recharge amount of SRI methodology with 5-day irrigation interval reduced 12% and 9% compared with continuous irrigation and rotational scheme (5-day irrigation interval), respectively. For the reduction of groundwater recharge when applying the SRI methodology in Taiwan, it is suggested that the relevant governmental agency should formulate effective measures for integrated groundwater resource management.

並列關鍵字

SRI ； FEMWATER ； irrigation schemes ； groundwater recharge ； infiltration rate

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