非圖台式空間決策支援系統於區域灌溉需水推估之應用

Abstract

台灣受地形、氣候等條件的影響，造成降雨時空分布不均，水資源規劃管理是一重要課題，尤其是針對佔總用水量超過70%的農業用水更需要有效的管理。因農業用水涉及諸如土壤性質、氣象、渠道輸水系統等諸多具有空間分布之因子，使營運管理相當不易，利用地理資訊系統(GIS)管理空間特性資料以建立決策支援系統，整合、分析灌溉需水推估之空間資訊並結合灌溉需水估算模式，提供管理者決策支援是一個相當有效提昇農業用水管理效能的方式。但傳統以GIS為基礎的空間決策支援系統可攜性較低，台灣有17個農田水利會，如要依據各區域農地特性建立空間決策支援系統，耗時費工且成本較高，加上因氣候變遷等因素，環境變化快速，如無法快速的更新各種資料，則無法提供有效且符合現況的資訊給予決策者支援與輔助。 本研究目的為透過試算表平台，建置非圖台式之區域灌溉需水推估空間決策支援系統，將空間資料特性整合於以試算表為基礎之系統中，提升系統之可攜性並且增加擴充彈性，除保留原決策支援系統之特性與優點，並可利於系統中擴充各種所需之模式與灌溉需水模式連結，可提供不同管理單位靈活運用。 研究中分別將系統於桃園、石門水利會灌區以及白河水庫灌區進行先驅應用研討，結果顯示本研究所建置之系統雖然少了圖資呈現，但考慮管理決策者應對其灌溉區域有相當程度了解，沒有圖資呈現對於系統使用者的影響不大；但少了圖層讀取限制卻可擺脫對GIS的依賴，而與決策相關的空間資料特性則予以保留，除可提升系統可攜性，亦增加系統資料更新時的便利性，並可將系統做擴充延伸設計，包括供需調配、經濟等不同面向分析，以提升不同區域、管理單位之決策效能，使有限的水資源得以有效的利用。

To efficiently manage the limited water supply resources is an important issue in Taiwan. The planning and management of agricultural water use is very important due to its large share (more than 70%) of the total water consumption. There are a lot of spatially related information, such as soil, crop weather and canal system, involved in the agricultural water management practices. Geographic Information System (GIS) was used to manage these spatial data and implement the Spatial Decision Support System (SDSS) for effectively manage the agricultural water use. The traditional GIS based SDSS is less flexible and portable and much difficult to implement or modify in different irrigation command areas or to adapt to the environmental change due to factors like global climate change. A non-GIS Excel-based DSS is proposed in this study to make the traditional SDSS more efficient, flexible and portable. Although the proposed system is not based on GIS, the necessary spatial characteristics for effective planning and management decisions are preserved. The system also provide user interface which makes scenario setup and simulation easy, therefore user can obtain necessary information for decision and realize the irrigation demand variation mechanism through changing the parameter of irrigation demand estimation and scenario situation. This proposed system is more portable and may be transplanted to different irrigation command area with less efforts. The command area of Taoyuan and Shimen irrigation associations and the Pai-Ho reservoir irrigation command area used as pilot study areas. The results show that this proposed system concept can provide fast and convenient regional irrigation water demand estimation to each Irrigation Associations in Taiwan. The system may also be extended to include the allocation model for supply and demand management, economic oriented analysis for better efficiency in planning and management of the limited water resources.