Net Water Natural Loss in the Main Channels of the Yellow River
黄河干流河道水量自然补损分析

The interactions between river runoff and air water exist in the forms of precipitation and evaporation. These interactions are parts of "four waters" interactions. Only consumed water and changing volumes of reservoirs are recalculated in the natural runoff recalculation and the water natural loss in the river channels have been deducted, so it is important to know the changes of natural runoff controlled by hydrological stations at river sections from quantitative analysis of the net water natural loss in the river channels, especially in the main river channel. First, the water balance equation is set based on the water balance principle to find the relationships between QRN, QC, P and QL in the river channel. Then the net water natural loss in six main river channels of the Yellow River are calculated. At last, the varieties of the net water natural loss in the main channels of the Yellow River are analyzed, and the conclusions are: (1) The water supplement is more than loss in the regions of Hekouzhen-Longmen and Sanmenxia-Huayuankou, while the water supplement is less than loss in the other regions in the river channels of the Yellow River. (2) Since 1960, the net water supplement has got less and less in the regions of Hekouzhen-Longmen and Sanmenxia-Huayuankou, but the net water natural loss is more and more in the other river channels. In all, the net water natural loss in the river main channels is increasing gradually and the value is 44.16×108 m3 in the 1990s. (3) The over-exploitation of groundwater is the essential reason for the increase of net water natural loss in the Yellow River.