考量農業用水之區域性地表地下水聯合調配(I)

Abstract

農業用水為台灣地區整體用水量之大宗,惟以往多數的水資源調配分析或是實際的實施方案大都是以公共用水為主要對象,對於農業用水往往在『用水量不增』的原則下,僅以『水權保留』的方式考慮之.『水權保留』雖然名義上在用水順序為第一優先,惟就水源調配而言,卻是一種消極的處理方式,因其對農業用水只是現況的維持,並未考慮農業水田環境生態的改變(如地下水位已經太低)或因應枯旱時期用水等,而亦必須進行水源長期或短期的調配,而此以濁水溪沖積扇最為明顯.本計畫全程預定為兩年計畫,目的即在針對濁水溪沖積扇應用系統分析方法,配合目前地下水、農業用水現況及地表大型水工結構物等,在積極考量農業用水下,對此區域進行整體的地表地下聯合調配.

Agriculture use is the major water demand in Taiwan. However, traditionally, most of the analysis for regional water distribution focused on fulfilling the industrial demands. The agriculture demand was considered through the "water right preserving". Although, it seems that the priority for agriculture water use is higher than other water demand when the agriculture water demand is preserved, the manipulation for agriculture demand is conservative. Been preserved as a higher water right, the agriculture water demand is to keep the same amount as it used to be, but not considering the potential need of long or short period water re-distribution caused by the hydrological or environmental condition such as the draught period or the depletion of groundwater water. This study is to apply state of the art system analysis methodology on conjunctive regional surface and subsurface water operation based on the existing groundwater resources, agriculture water use and major water resources infrastructure. Instead of preserving as a water right, the system will explicitly consider the agriculture demand as a demand to be fulfilled and operated.