中文摘要：

山丘区小流域地形特征及数字水系的自动提取为山洪防治提供了必要的数据准备。本文采用地形特征自动提取软件包Digital Hydro．对山区小流域地形及水系基本信息进行了提取试验。研究中，地形数据引用栅格型DEM数据SRTM，水平分辨率接近90m，研究对象为浙江省姜湾水文实验流域。该流域拥有3个流量站，提取的集水面积分别为20．64km^2，10．21km^2，1．31km^2，误差分别为-1．2％，0．1％和-3．0％。分析显示，流域地形总体起伏较大，平均坡度为33％，现有DEM分辨率能满足流域水系等基础信息的提取。但在河谷地带存在洼地，造成提取的水系与实际情况存在一定差异，提取水系时．局部需要引入空间分辨率更为细致的地形信息。

英文摘要：

Automatic digital drainage network extraction for hilly catchment is of great importance for flash flood forecasting. An experiment was carried out for digital drainage network extraction by DigitalHydro software package. In this study, DEM is from SRTM （Shuttle Radar Topography Mission） with a horizontal resolution 90m. The Jiangwan experimental catchment with an area 20.9km^2 and three flow guaging stations was adopted. The catchment areas extracted by DigitalHydro are 20.64km^2, 10.21km^2 and 1.31km^2, and the errors are -1.2%, 0.1% and -3.0%. It is shown that the terrain is fluctuant and the mean slop is about 33%. However, there are some depressions in river valley region which lead to some relatively larger errors between the digital and manual extracted channels. So, it is suggested that DEM of local area in valley need to be re-sampled by terrain data with higher resolution.