本研究旨在揭露大湖溪中上游河道形態、河床材料與其集水區內地文參數的關係。研究素材包括從1:5000 像片基本圖上取樣繪製的橫剖面、河床梯度、野外量測所得的岩體強度、河床粒徑，以及經由ArcGIS 網格運算所推得的集流面積等地文因子。利用史密特岩石硬度計所測得的岩體強度，依據地層分類、分別對比前人所測資料，呈現高度相關，顯示其定義相對岩石強度的一致性。本研究針對河道形態、河床梯度、河床材料提出3 項結論。
(1) 從主河道上下游不同地質區抽取共29 個河谷橫剖面，並將各剖面從河床底向上高度累加其截面積，獲得29 條累加截面曲線。此累加截面曲線與集流面積、平面型態、岩體強度作相關描述，得河谷橫剖面形狀受到集流面積的影響
最大。
(2) 河床梯度主要受到地層傾向、岩體強度兩者影響。把水流方向依照與地層傾向的夾角分為順層型、垂直型、反斜型，從14 個地質帶的分類結果得知，反斜型的河床梯度最高。河床梯度只在研究區西側受岩體強度影響較顯著。總體
而論河床梯度受到構造的影響最大。
(3) 河床材料與地質區有間接關係。岩體強度強的地質區所通過的河流可能擁有較粗糙的河床材料。
This study aims to explore the relationship between channel morphology,
channel bed materials and the physiographic parameters of Dahu River catchment.
Research materials include 1) cross-section profiles of the valley being abstracted from 1/5000 aerial photos, 2) channel bed gradient, 3) the hardness of rocks measured by Schmidt Hammer, 4) the particle distribution of river bed gravels,
5)physiographical parameters (such as drainage area) of the catchment being deduced
from DEM by ArcGIS. The hardness of rocks, being measured by Schmidt Hammer, of geological units are well-correlated with those measurements done by others in literatures. This study leads to the following three conclusions.
(1) 29 cross-section profiles are abstracted from 1:5000 topographic map along the main stream, and they are demonstrated by the cumulative area curves calculated along the elevation from the river bed upward. This form of the valley cross-section is mainly determined by its drainage area.
(2) The channel bed gradient is mainly influenced by the strata orientation and the rock strength. In accordance with the flow direction and the inclination orientation of the strata formation, three situations can be defined 1) the subsequent type, 2) the
vertical type, and 3) the obsequent type. Between them, the channel bed gradient of
the obsequent type is highest. The channel bed gradient Only in the west section of
the study area, the channel bed gradient shows a significant influence from the impact
of the rock hardness. In general, the channel bed gradient is most affected by the
geological structure.
(3) The relation between the channel bed material and the geological regions is insignificant.
