土地利用变化和气候变化对温榆河上游流域径流变化的影响

土地利用和气候是直接影响流域水文水资源的两个主要因素,其影响分离的研究对流域的土地利用规划和水资源管理具有重要意义。以温榆河上游流域为研究对象,在统计分析1980-2014年流域气象因子、土地利用变化趋势的基础上,通过SWAT模型模拟与情景设计相结合的方法,评估了气候变化和土地利用变化对温榆河上游径流变化的影响。结果表明,SWAT模型在温榆河上游流域模拟效果良好,率定期和验证期的决定系数R2分别为0.80、0.77,纳什系数Ens分别为0.79、0.74。流域降雨量和气温呈递增趋势,林地和耕地减少,城乡及工矿和居民用地增加,草地在1995年到2005年间增加,这些变化综合影响了流域的径流变化,使得径流先增加后减少。其中气候变化的贡献率为100.46%,土地利用变化的贡献率为2.09%,气候变化的影响远远大于土地利用变化的影响。因此,如何应对气候变化在温榆河上游流域水资源管理工作中值得重视。

Impacts of changes in land use and climate on runoff variation in the upper reaches of Wenyu River

Land use and climate are two main factors directly influencing catchment hydrology and water resources. The separation of their effects is of great importance for land use planning and water resources management. On the basis of statistical analysis of the change trend of meteorological factors and land use from 1980 to 2014, we assessed the impacts of climate change and land use change on the runoff change in the upper reaches of Wenyu river by combining SWAT model simulation and scenarios designing. Results indicated that the SWAT model is a powerful tool to simulate the effect of environmental change on runoff in the upper reaches of Wenyu River. The correlation coefficient R2 and Nash coefficient Ens were 0.80 and 0.79 respectively during the calibration period, and were 0.77 and 0.74 respectively during the validation period. The rainfall and temperature gradually increased; the forest land and cultivated land decreased gradually; the urban and rural areas increased gradually;and the grassland gradually increased during 1995 to 2005. These changes synthetically affected the runoff and caused the runoff to increase first and then decrease. The contribution rate of climate change to runoff was 100.46% , and the contribution rate of land use change to runoff was 2.09% . The climate change had greater influence on the runoff than the land use change in the upper reaches of Wenyu River during 1980-2014. Therefore, how to cope with climate change is worthy of attention in the water resources management.