本文利用淹水模式模擬暴雨期間之淹水情形,地表坡度直接影響地表逕流之漥蓄與流向,而數值計算之精度取決於網格解析度。本研究利用FLO-2D模式模擬台東縣境內之利嘉溪流域子集水區200年重現期一日降雨之淹水範圍及淹水深度,分別採用40 m × 40 m、80 m × 80 m、120 m × 120 m、160 m × 160 m及200 m × 200 m等5組網格解析度進行模擬,以分析網格解析度對淹水模擬結果之影響,模擬結果顯示區域淹水30公分以上之時,網格解析度愈高淹水網格數目及淹水面積有增加之趨勢,網格解析度愈高愈能顯示局部低窪之地形變化,選擇愈高網格解析度,則模擬淹水所需計算時間遞增。
This study used inundation model to simulate flooding situation during rainstorm period. The surface slope directly influences depression storage and flow direction of surface runoff. But precision of the numerical computation is decided by grid resolution. This research using the FLO-2D model simulates flooding ambit and depth with 200 year return period in one day raining within sub-watershed in Lee-Chai Creek, Taidong County. Five types of grid resolution, 40 m × 40 m, 80 m × 80 m, 120 m × 120 m, 160 m × 160 m, and 200 m × 200 m were conducted to simulate inundation situation that purpose was to answer the impact of ambit and depth on grid resolution. The analytic results showed the flooding grid numbers and area increased in higher resolution conditions during flooding depth greater than 30 cm. This suggested higher grid resolution can reveal the local low-lying terrain change, but higher grid resolution had progressively increased time to compute flooding situations.