本文探討臺灣花東縱谷南段卑南溪河谷沖積扇之自然特性及其與土地利用 和水土災害之關係。本硏究以沖積扇之地理位置、地形成因和發育階段等特性爲 基礎進行分類，有效地呈顯硏究區之地形作用、地殼運動特性，並藉此分類以掌 握人類活動強度與災害類型，有助於本區土地資源利用規劃與災害防治。 硏究發現，土地利用槪以中段鹿野爲界，北段有早作地、果園、茶和水田分 布，南段除利嘉扇扇端有水田外，餘者扇面上皆爲釋迦果園。本河谷安全性高的 地區分布於高臺、龍田等階地；景豐、永昌、永安等沖積扇階地面；或具規模之 河谷扇扇央之太平、康樂地區以及兩扇交會之永豐、瑞和等河問區。惟若其位置 適爲山溪扇扇端處則仍有洪水之虞，如關山、海端；河域兩側河川能量集中之攻 擊坡處、扇頂之谷口與扇端等爲土石災害高危險區。 硏究也發現，本河谷沖積扇自然特性、土地利用與土石災害三者呈顯互動關 係，惟易災區土地利用雜度稍高，或與本區河床皆經整治有關，是以土地利用與 災害之互動關係反不若沖積扇自然特性之與土地利用關係爲大。

The Peinan River is situated at the southern part of a longitudinal valley in Eastern Taiwan. The effects of, and the relationship between, the natural environment and human activities on alluvial fans were surveyed, analyzed and discussed in the context of geographical location, geomorphological processes, stages of development, land uses and geological hazards in order to promote understanding of the natural mechanisms operating in the study area and to contribute to land resource planning and hazard prevention. Towns and villages located on stream terraces, such as Gau-Tair, Long-Tyan, or on elevated alluvial fans, such as Jiing-Feng, Yeong-Chang, are rarely subject to geological hazards. On the other hand, those on or nearby mountain stream alluvial fans such as Guan-Shan are prone to debris flows, and those at the lower end of valley fans, such as Pei-Nan, are subject to flooding during typhoon seasons. The study also found that land use has a closer relationship to fan characteristics than it has to debris hazard. This is a result of the construction of channels and dykes.