渭河上游典型小流域水文特征差异性分析

Analyzing the hydrological characteristics and differentiation over the typical small basins in the upper reaches of the Weihe River

根据渭河流域两个典型小流域的实测水文和气象资料,分析了不同气候和下垫面条件的流域水文特征及其差异性.结果表明:清源河和牛谷河流域的年平均气温呈上升趋势,降水、径流、泥沙、降水径流系数均呈减少趋势;两个流域的降水、径流和泥沙历年变化不一致,1998-2013年清源河流域降水量相对牛谷河流域减少了8.6%,1993-2013年牛谷河的径流相对减少了21.4%,2000-2013年清源河的泥沙相对减少了24.0%;两个流域的面积、河长、海拔、植被覆盖率等流域特征值相对差在-29.4%^-4.5%之间,气温、降水等气候特征值相对差在-27.4%~16.7%之间,而径流特征值相差较大,相对差在-90.2%^-84.7%之间,泥沙特征差异性更大,相对差在292%~347%之间.对气候、下垫面和人类活动对水文要素的影响进行了研究,受人类活动的影响,清源河流域1996-2013年年径流减少11.6%,牛谷河流域1993-2006年年径流减少25.9%,2007-2013年再减少10.5%,研究人类活动的调水减沙效应,对流域综合治理、生态环境建设具有一定的指导意义.同时,充分利用不同小流域实测水文气象数据,分析水文气象要素的变化规律,可以为分布式水文模型研究和中小河流洪水预警预报提供重要依据.

According to the measured hydrological and meteorological data over the two typical small basins in the Weihe River basin,the basin hydrological characteristics and differentiation with different climate and underlying surface were analyzed. It is found that in Qingyuan River and Niugu River basins the annual average air temperature is rising,the precipitation,runoff,silt discharge and precipitation runoff coefficient are totally decreasing; annual variations of precipitation,runoff and sediment are not the same. In 1998- 2013,the precipitation of Qingyuan River basin decreased 8. 6% as compared with that in the Niugu River. From 1993 to 2013,the runoff of Niugu River had decreased 21. 4%; from 2000 to 2013,the silt discharge of Qingyuan River had decreased 24. 0%. Between the two basins,the differences in area,river length,elevation and vegetation cover rate are- 29. 4% ～- 4. 5%; the differences of air temperature and precipitation are- 27. 4% ～ 16. 7%; the difference in runoff is- 90. 2% ～- 84. 7%; the difference in silt discharge is 292% ～ 347%. Study of the impacts of hydrological factor on climate,underlying surface and human activities shows that from 1996 to 2013,Qingyuan River basin runoff had decreased 11. 6%; from 1993 to 2006,Niugu River basin had decreased25. 9%; and then from 2007 to 2013,had decreased 10. 5%. By the way,the diversion sediment reduction of human activities has a certain direction significance for basin comprehensive management and ecological environment construction. Meanwhile,full using different small watershed hydrological-meteorological data to analyze the changes of hydro-meteorological elements can provide an important basis for using distributed hydrological model to serve medium and small river flood forecasting and warning.