位於高雄市和臺南市交界的二仁溪流域，是高雄地區最早有漢人移 住開墾的地方。然而最早開發的優勢，並未對本流域的日後發展帶來有 利的影響，不論是上游的丘陵地區，或是下游的平原地帶，二仁溪流域 長期以來都是南部地區發展相對落後的地帶。 二仁溪流域青灰色泥岩層廣布，是塑造地區特性的主要自然條件。 以農業經營條件而論，以青灰色泥岩為主的土地贍養力低下，導致發展 潛力不足是造成二仁溪流域聚落發展相對落後的原因，而二仁溪流域的 岩層軟弱，河流沖刷力強，河道經常沖崩改道，則影響聚落發展的穩定 性。 二仁溪流域的自然環境變遷，主要表現在河流的改道上，流域內 廣布的泥岩則是導致變遷的最主要環境因子。泥岩的透水性極差，膠結 程度低，大雨過後大部分的雨水皆以地面逕流的形式流動，常在坡面形 成泥流，造成邊坡的高度不穩定性，一方面讓河岸以較快的速度後退， 崁頂平地面積逐漸縮小，威脅到以此等平地作為住宅用地的聚落安全； 另一方面也造成作為分水脊的山稜線經常移動，山脊是本區在步行時代 的主要步道，其位置常常改變，連帶也造成本區傳統的交通路線經常改 易。而泥流流進河道後也造成溪水混濁，大量含沙的河流也因此帶有易 淤、易決且經常改道的特性。不論是交通路線的改變，或是河崖崩坍、 河川泛濫、改道，都會對流域內既存聚落的發展甚至生存，產生一定程 度的影響。由於河流上下游間的沖崩淤積作用有別，對聚落的影響也不 一樣。 二仁溪上游的河流地形變化，多來自河道的沖崩及曲流的截斷，或 因河崖後退，影響聚落安全，或因交通路線的變化而沒落；中游段的河 道相對穩定，只有在與六甲溪會流口附近，有比較明顯的改道現象，因 此造成一些聚落的消失或搬遷；相對於上、中游的沖崩和改道，二仁溪 的下游則是河道不斷延長，在延長的過程中，河道雖不穩定，卻沒有因 河道變遷而遷村或廢村的記載。至於內海周圍也有部份村莊的發展受到 內海淤積的影響，對這些村莊而言，二仁溪對它們的影響是間接的，而 非直接的安全威脅。

The Erren River was the one of the earliest migration’s place for the Han people that settled in Kaohsiung area. Although being an initial development area, in reality this initiative did not create a positive momentum for local further development both on upstream and downstream of the Erren River. The Erren River area has widespread layer of blue-gray mudstone which is the natural soil composition around that area. From the agriculture point of view of poor fertility, the soil has a low environmental capacity. Consequently soil composition has been identified as the main reason for the slow the development of the area. At the same time due to unstable river bank caused by the soft rock and strong river erosion there are frequent collapses of the bank changing the course of the river resulting in the transitory nature of the village establishment. With the changes to the profile, course and flood potential of the river this has a direct impact upon travel pathways such as transport routes and the instability of walking paths due to river embankment being collapse. All these events have negative influence upon the development of surrounding villages. A further variable of the river as it rushes between upstream and downstream is the role of siltation which results in random permutations of river bank collapse outcomes, with again a disparate set of consequence laid upon the settlements. Upstream of the Erren River is an outcome of the collapsed of river embankments, rerouting of the river itself, siltation of the river profile changes and river cliff retreat. Some villages may disappear through flood or become navigationally isolated which require redevelopment or relocation. Downstream the Erren river’s has experienced course change and has become extended that is longer in length which results in again an unstability of the river. Some of the villages located around lagoon with its development affected by the lagoon sediment. For these villages, the impact form the Erren River is indirect and not a direct safety threat.

二仁溪；泥岩；土地贍養力；聚落；河道變遷

Erren river；mudstone；environmental capacity；settlement；river course change