黑河流域历史时期水资源利用空间格局重建

黑河流域水资源开发利用的空间格局历史演变在中国西北干旱区具有典型性和代表性,对其进行复原并总结经验教训,对现代水资源开发具有宝贵的借鉴意义。利用历史文献、古今地图、遥感影像等资料,结合实地考察,在地理信息系统技术的支持下,对黑河流域历史时期水资源利用的空间格局进行重建,并分析其演变过程。结果表明: 该区域大规模的农业水资源利用开始于汉代,其范围覆盖流域中下游沿河平原和三角洲的大部分地区。魏晋南北朝时期虽然总体上承袭了汉代的格局,但局部地区萎缩明显。隋唐时期,中游地区灌区规模较大,但随着唐中叶吐蕃的入侵而遭破坏。宋元时期,水资源开发利用仅在主要绿洲的核心区有所分布。明、清直至民国时期,中游地区渠系增加,密度增大,灌区出现沿河向上的溯源扩展和由近岸向两侧的外延扩展,一些地势较高的山前绿洲也被开垦,水资源利用强度持续增加、规模扩大,最终奠定了现代水资源开发利用的空间格局。但是,此时的下游却处于游牧状态,无大规模开发活动。可以发现,明代以前水资源开发利用波动频繁,兴废不定;而明代以来,中游灌区规模稳定扩大和下游萧条情况形成鲜明对比。水资源利用引起尾闾湖萎缩、土地盐渍化、沙漠化等生态问题逐渐显现。

Reconstruction of historic spatial pattern for water resources utilization in the Heihe River basin

Historic evolution of spatial pattern for water resources development and utilization in the Heihe River basin is representative in the arid regions of Northwest China. Reconstructing the spatial pattern and accumulating the experiences in historical periods could provide valuable references for water resources exploitation in modern times. Using historical documents, ancient and modern maps as well as remote sensing images as data sources and combined with a series of field investigations, this paper reconstructed the spatial pattern of historic water resources development and utilization in the Heihe River basin and analyzed the spatial evolution with the aid of geographical information system. The results indicated that large-scale water resources development and utilization in this basin started in the Han Dynasty, with its scope covering most parts of plains and deltas in the middle and lower reaches. The development activity was inherited in the Wei-Jin, Southern & Northern dynasties but shrank obviously in some local parts. In the Sui and Tang dynasties, large irrigated areas were distributed in midstream but they were destroyed by Tubo's invasion in the mid-Tang Dynasty. In the Song and Yuan dynasties, there were only small ranges in core oasis regions. From the Ming Dynasty to the Republic of China, the number and density of channels increased dramatically, expanding to river origins and their peripherial areas even in the regions near mountains with high elevation in the south. Thus the strength and scale of water resources development and utilization rose continuously, which laid the groundwork in modern times. However, nomadism dominated in the downstream and large-scale water resources development and utilization did not exist in these periods. It can be observed that water resources development and utilization before the Ming Dynasty fluctuated frequently with several rises and falls, while the sharp contrast can be observed between the middle and lower reaches, with stable expansions of irrigated areas in midstream and depressed conditions in downstream respectively. In addition, irrational water resources utilization led to ecological problems such as recession of terminal lakes, soil salinization, and desertification.