干旱区内陆河流域典型灌区土地利用变化与耗水量研究

Research on Land Use/Cover Change and Water Consumption in Typical Irrigation Areas of Inland River Basin in Arid Region

【目的】以阿克苏河灌区为例,研究干旱区内陆河流域土地利用变化与耗水量的关系,为干旱区土地资源开发与保护提供科学依据。【方法】基于2000~2014年TM遥感影像,运用GIS技术和土地利用模型,结合灌溉用水量和土壤含水量的变化趋势,分析近15 a阿克苏河灌区土地利用/覆被变化现状以及耕地扩张与灌区耗水量的关系。【结果】阿克苏河灌区土地利用变化明显,灌区耕地面积以159.8 km2/年的速度增加,以塔河灌区耕地增加最为明显;随着灌区耕地面积的急剧增加,灌区内耗水量加大;灌区内土壤含水量减少,平原荒漠区的一些浅根系荒漠植物因干旱胁迫死亡,中、低覆盖草地面积大幅下降,灌区外围荒漠化风险加大。【结论】在全球变暖背景下,耕地面积的不断扩大,是导致灌区耗水量增加的主要原因。

【Objective】Taking Aksu River Irrigation area as an example,this paper focuses on the relationship between land use/cover change and water consumption in inland river basin in arid area,and provides scientific basis for land resource development and protection in arid areas.【Method】Based on the land use/cover classification data derived from the Landsat TM imageries in 2000 and 2014,using GIS technology and land use models,combined with irrigation water and soil moisture,this paper analyzed the relationship between land use/cover change and the water consumption of cultivated land expansion in the past 15 years in the irrigated area of Aksu River.【Result】The results showed that the land use change was obvious in Aksu River Basin irrigation area.The cultivated land area increased at a rate of 159.8 km 2/year,which was especially obvious in the Tarim River irrigated area.With the increase of cultivated land area,the water consumption of irrigated area increased obviously,and the soil moisture decreased.The shallow-root desert plants would die due to the drought stress.The middle and low coverage grassland area decreased significantly,causing the risk of desertification in the peripheral area of the irrigated area of Aksu River.【Conclusion】Under the background of global warming,the continuous expansion of cultivated land area is the main reason leading to the increase of water consumption in the irrigation area of Aksu River Basin.