黑河中游张掖绿洲灌溉渠系的数字化制图与结构分析

The Irrigation Channel System Mapping and Its Stucture Analysis for the Zhangye Oasis in the Middle Heihe River Basin

人工灌溉渠系对于干旱区内陆河绿洲的生存和发展具有重要作用。以黑河中游的张掖绿洲为例,在收集大量高分辨率遥感影像和地形图资料的基础上,利用GPS实地测量和GIS软件提取了全绿洲干、支、斗3级渠系信息,获得了翔实准确的灌溉渠系空间和属性数据,首次完成了张掖绿洲灌溉渠系的数字化制图并对该渠系网络的空间格局进行了分析。结果表明:张掖绿洲目前渠道总数约为6 300条,总长为8 749.51 km,密度为0.47 km/km2,干、支、斗渠的比例为1∶1.17∶2.4。5个县区中甘州区的灌溉渠系分布最密集,而山丹县渠系建设相对落后。绿洲人工灌溉渠系建设方式和水资源利用开发程度是影响和改变本地区流域景观结构和土地利用方式的重要因素。

The artificial irrigation channel system plays a significant role in the development of the Zhangye oasis in the middle Heihe River Basin, northwest China. By using remote sensing, GIS and GPS approaches, the digital irrigation channel system map of the Zhangye oasis was firstly compiled based on a large number of high spatial resolution topographic maps and satellite images as well. This digital map includes the detailed spatial and property information of the Zhangye oasis＇ irrigation channel system in three levels （main channel,branch channel and tip channel） and has been widely validated and calibrated by intensive GPS ground-measurements over all the channel network of the oasis. The channel spatial structure and its relation with the local land use evolution were analyzed in this study. Currently, the total number of the irrigation channels in the Zhangye oasis is about 6300,in which the main channels,the branch channels and the tip channels account for 21.9% ,25.54% and 52.54% ,respectively. The total length of the whole channel dan county has a relatively poor channel construction. The development of the artificial irrigation channel system and the water resource exploitation in the arid oases could greatly affect and change the local land- scape pattern and land use style.