乾旱時期用水分配模式之研究---子計畫：乾旱時期地面水與地下水聯合運用作業模式研發(I)

Abstract

地面水源受水文豐枯影響甚劇，於乾旱時期常有水源不足之情況發生，而地下 水相對於地面水源而言，受水文變化影響較小，因此若能將地面水與地下水進行聯合 運用，應可有效降低乾旱時期之缺水風險。台中地區由於工商業的蓬勃發展以及科學 園區的進駐，致使用水需求量有急速增加的趨勢，現有水源設施不足以供應此龐大的 需求量，故本計畫擬透過地面水與地下水水資源有效聯合營運，以提昇中部地區水源 調度能力，降低乾旱時期的缺水風險。 由於台中地區地面水調配系統複雜，各水源常需跨流域支援，加上局部地區有 地下水超限利用之情形發生，因此需有詳細之地下水和地面水系統數值模式以供探討 分析，故本計畫將分三年進行。第一年針對台中地區建立地下水數值模式，評估台中 地區天然補注量、抽水量與地下水可開發量。第二年建置台中地區地面水源調配模 式，並進行模式檢定及乾旱時期水源調配模擬評估。第三年研擬地面水與地下水聯合 運用原則及方式，完成地表地下聯合營運模式之整合，並進行地面水與地下水各種聯 合運用方案之模擬分析。

The time variation of surface water resources depends on the hydrological condition, therefore, using only surface water may cause sever water deficit during drought situation. On the other hand, groundwater is much more stable than surface water and is a good water resource alternative to reduce water deficit risk during drought situation. In Taichung area, industrial growth and development of Science Park is significantly increasing the water demand and the existing water resources system cannot fulfill the increasing water demand. Therefore, this study is to develop a surface and subsurface conjunctive-use management model for assisting to reduce the water deficit risk of Taichung area. In Taichung area, the cross-basin water transport and groundwater over pumping induced a complicated water allocation problem and a model to analyze the water allocation system is necessary. This research will continue for three years. In the first year, a numerical groundwater simulation model will be developed to evaluate the natural recharge, pumping rate and safe groundwater yield. In the second year, surface water allocation model will be developed to analyze the water deficit caused by drought condition in Taichung. For the last year, conjunctive-use operating rule will be defined and the surface water allocation model and groundwater simulation will be integrated to develop a conjunctive-used management model for Taichung area. The proposed model will be used to assess the performance of various water resources improvement alternatives.