Analysis of Rainfall-Runoff Factor Change of the Source Regions of the Yellow River With Supporting of GIS

The annual average and rain season precipitation and yearly runoff of the source regions of the Yellow River were analyzed. Annual average precipitation of Maduo station that locates in the northwest of the regions changes with small extend, but annual average precipitation of Jiuzhi station that locates in the southeast of the regions of rich precipitation shows a greatly decreasing tendency, which brings adverse impact on the runoff yield of the source regions of the Yellow River. Intra-annual precipitation changes relatively greatly in rain season and shows a decreasing trend. Taking into account of inter-annual variation of yearly runoff, the authors computed the variation coefficient, absolute inter-annual change rate and non-uniformity coefficient of runoff, and illustrated that the annual average runoff fluctuates relatively greatly. Finally, it is pointed out that rainfall intensity and rainfall volume are the main reasons for runoff coefficient changes.