宁蒙河段水沙变化数值模拟及灌区引水对河道水沙变化的影响

Numerical simulation of water and sediment change in Ningxia-Inner Mongolia reach and the impact of water diversion on water and sediment change in river course

利用非恒定水动力学水流泥沙方程,建立了黄河下河沿～头道拐河段一维水沙输移数学模型,分别采用1997-2002年和2003-2006年的黄河水文、泥沙等资料对模型进行了率定和验证;运用该模型模拟计算了1997-2006年宁蒙灌区引水对河道水沙变化的影响,分析认为:宁蒙灌区每引水1亿m3,头道拐断面相应径流减少量0.69亿m3,每净引水1亿m3头道拐断面径流则减少1.02亿m3;相应输沙减少量分别为40.9万t和60.7万t;河道淤积变化量1 432万t。汛期引水对河道输沙变化的影响大于对径流变化的影响,汛期引水引起的头道拐断面径流减少量占引水期径流减少总量的50%,而相应的输沙减少量则占输沙减少总量的73%。

Using current and sediment equation in the non-constant hydrodynamics,the paper set up a one-dimensional mathematical transport model of water and sediment in the Xia Heyan to Tou Daoguai reach.Using the hydrologic and sediment data of the Yellow River 1997 to 2000 and 2003 to 2006,it calibrated and verified the model.The use of this model simulated and calculated the impact of the irrigation area diversion to the sediment changes in riverway of the Ningxia-Inner Mongolia from 1997 to 2006.The analysis recognized： when Ningxia-Inner Mongolia irrigation area water diversion of 100 million m3 each,corresponding runoff volume will reduced 69 million m3,in Tou Daoguai section when net water diversion of 100 million m3,the Toudaoguai section runoff volume will be reduled 102 million m3;corresponding the amount of sediment will be reduced 409,000 t and 607,000 t respectively,riverway siltation changes in the amount of 1432 million t.The influence of flood season diversion to sediment change in the river course was bigger than the influence of runoff change the which the flood season diversion causes turns the Tou Daoguai section runoff decrement to account for the diversion time runoff reduction total quantity 50%,but corresponding loses the sand decrement to occupy loses the sand reduction total quantity 73%.