基于SWAT的西北干旱区县域水文模拟——以临泽县为例

以西北干旱区的临泽县为例,利用1980—2012年的气象数据、土地利用数据、土壤数据、数字高程数据驱动SWAT模型,对县域水文过程进行了模拟并对行政区内的水资源状况进行了时空特征分析。研究表明临泽县1980—2012年均实际蒸发量、下渗量、壤中流补给量、地下水补给量、产流量、可用地表水资源量和产流系数分别为130.53、49.78、68.95、48.00、53.47 mm、(13.17±0.60)×108m3和0.16;生态用水量大(3.56±0.12)×1011m3),且呈现出增加趋势。由于黑河分水措施的影响,各水量要素的突变年份出现在2000年之后的5年内。从空间分布上看,地下水补给量和产流系数都呈现“南高北低”的趋势。研究结果也表明临泽县1980—2012年的产流量由地下水补给量控制,壤中流和地下径流的贡献分别为43%和57%;而可利用水资源量主要依赖上游的来水,上游来水量的贡献率达到83%。此外,我们的研究也发现临泽县2007—2012的实际蒸发持续增加,从而导致“蒸发悖论”现象的存在。

Hydrological modeling based on SWAT in arid northwest China: a case study in Linze County

In this paper, multiple data sources (including weather, soil, land use, and digital elevation data) from 1980 to 2012 were applied to drive the SWAT model. The hydrological process was modeled at the county scale, and the spatio-temporal changes in water resources were analyzed with the model outputs in the arid northwestern county of Linze county. The results showed that annual mean evaporation, infiltration, lateral recharge, underground recharge, water yield, available surface water, and yield coefficient were 130.53 m, 49.78 mm, 68.95 mm, 48.00 mm, 53.47 mm, (13.17 ±0.60)×10⁸ m³, and 0.16 during 1980-2012, whereas the average annual ecological consumption of water was (3.56 ±0.12)×10¹¹ m³ and presented an increasing trend. Further analysis indicated that the lateral recharge and underground recharge were the controlling factors of water yield, whose contributions were 43% and 57%, respectively. Moreover, the results showed that hydrological processes were driven mainly by the scheme of "water diversion in Heihe River", and all of abrupts for hydrological elements occurred from 2000 to 2005. Spatially, actual evaporation, underground recharge, and yield coefficient across Linze county was higher in the south than in the north. Further analysis indicated that lateral recharge and underground recharge were the factors controlling the water yield, whose contributions were 43% and 57% respectively. Available surface water in the Linze during 1980-2012 was controlled by upstream inflow, which contributed up to 83%. In addition, our study found there was evaporation paradox during 2007-2012, which is attributed to the continual increase in actual evapotranspiration.