摘要:
自从20世纪70年代以来,黄河入海泥沙通量表现出明显减少的趋势.研究表明,入海泥沙通量对于上、中游不同的水沙来源区降水变化的响应方式是不同的.在假定其他因素相同的情况下,龙门至三门峡区间的年降水量每减少10mm,入海泥沙通量将减少0.275亿t;河口镇至龙门区间的年降水量每减少10mm,入海泥沙通量将减少0.143亿t;兰州以上年降水量每减少10mm,入海泥沙通量减小0.174亿t.多沙细砂区降水的减少对于黄河入海泥沙通量的影响最大.通过多元回归分析建立了入海泥沙通量与年降水、梯田林草面积、淤地坝造地面积之间的定量关系:在其他因素不变时,梯田林草面积每增加104hm2,入海泥沙通量将减少0.0019亿t/a;年降水量每减少10mm,入海泥沙通量将减少0.543亿t,淤地坝造地每增加104hm2,入海泥沙通量将减少0.0205t/a.这些数据可为未来各影响因子进一步变化后入海泥沙通量变化的估算提供依据,为黄河流域和河口的环境规划服务.
Abstract:
Since the 1970s,the sediment flux of the Huanghe River into the sea has shown a marked tendency of decrease,which is unfavor able to the wetland protection and oil extraction in the Huanghe River Delta.Thus,effort is made to elucidate the relation between the sediment flux into the sea and the drainage basin factors including climate and human activities.The results show that the sediment flux into the sea responds to the changed precipitation in different ways for different water and sediment producing areas in the drainage basin.Other factors are given as constant,when the annual precipitation in the area between Longmen and Sanmenx ia decreases by 10 mm,the sediment flux into the sea will decrease by 27.5 Mt/a;when the precipitation in the area between Hekouzhen and Longmen decreases by 10 mm,the sediment flux into the sea will decrease by 14.3 Mt/a;when the precipitation in the area above Lanzhou decreases by 10 mm,the sediment flux into the sea will decrease by 17.4 Mt/a.Amultiple regression equation has been established between the sediment flux into the sea and the influencing factors,such as the area of terrace land building and tree-and grass-planting,the area of the land created by the sediment trapped by checkdams,the annual precipitation and the annual quantity of water diversion by man.The equation may be used to estimate the change in the sediment flux into the sea when the influencing variables are further changed,to provide useful knowledge for the environmental planning of the Huanghe River drainage basin and its delta.
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