, Horton , km Tsinghua Tongfang Optical Disc Co., Ltd. All rights reserved. Vol. 21, No. 2 GEO GRAPHICAL RESEARCH

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1 Vol. 21, No. 2 GEO GRAPHICAL RESEARCH Mar., 2002 : (2002) (, ) :, , 6 15,,,,,, : ; ; : P93111 ; P33314 : A, [1, Horton 1942 ], [2 10, ],,,,,,,,,,,,,, km 2, 1,,,,,, : ; : : (CXIO G2A ) ; ( ) : (19442),,, 1 50, 30, 4 E2mail :

2 172 21,,, 6 :, +,, +,,,,,,,,,,,,,, 10 32, cm 2 ( 20km 2 ), 1,,, : 3mm,, [11 ] 2 (Dd).,,,, 1 Fig11 Relation between sediment yield and drainage density for different types of river basins in the Middle Yellow River

3 2 : 173 1,,,, ;,,,,,,, + +, 1,,,,, +, +,,,, +,,,,,,,,,, ;,,, 3 15,,,,,,,,,, 15,, > % [12, > 15 ],, 15 (Si) Si, ;,, Si, 2 2, +, Si,

4 174 21, ( 2 1) ( 2 2), Si, ( ),,,,,, ;,,, ( 2 3) ( 2 4),,, Si, 2 15 Fig12 Relation between sediment yield and percentage of inter2gully area with slope steepness less than 15 for different types of river basins in the Middle Yellow River + Si,,,, ;,,, Si Si,, 2 a b, ( ),,

5 2 : [13,14, S. A. Schumm ] (Rf),,,,,,, 3 Fig13 Relation between sediment yield and relief ratio for different types of river basins in the Middle Yellow River 3 3,,,,,,,, ;,,,,,, (Ds) (C) Dd H,, ( ),, ;, (C), ; ( H),,,,

6 176 21,, 5 1,,,, 1 Tab11 Correlation between sediment yield and basin morphological characteristics for different types of river basins in the Middle Yellow River Dd Si Rf Ds Dd H C 2 Tab12 Multiple correlation between sediment yield and basin morphological characteristics for different types of river basins in the Middle Yellow River Qs = Dd Si Qs = Dd Si Qs = Dd H Si Qs = Dd H Tab13 Correlation coeff icient of Step Multiple Regression between sediment yield and basin morphological characteristics for different types of river basins in the Middle Yellow River ,,, 15 ; + +,,,,,,,, ;

7 2 : 177,,,,,, 2,,,,, ; +, Dd H ( 3),,,,,, : [ 1 ] Horton R E. Erosional development of streams and their drainage basin,hydrological approach to quantitative morpholo2 gy. Geol. Soc. Amer. Bull.,1954,56, [ 2 ] Gregory K J, Walling D B. Drainage Basin Form and Process : a Geomorphological Approach. Edward Arnold, [ 3 ] Schumm S A. The Fluvial System. John Wiley & Sons, [ 4 ],,.. :, [ 5 ],,.. :, [ 6 ],,.. :, [ 7 ].. :, [ 8 ]..,1987,6 (1) : [ 9 ]. 1,1998,17 (3) : [ 10 ]. 1,2001,20 (3) : [ 11 ]... :,1992. [ 12 ].. :, [ 13 ] Schumm S A. Evolution of drainage systems and Slopes in Badlands at Perth Amboy, New Jersey. Bulletin of Geological Society of America, 1956,67 : [ 14 ] Hadley B P, Schumm S A. Sediment Source and Drainage Basin Characteristics in Upper Cheyenne River Basin. U. S. Geological Survey, Water - supply paper B,

8 Effect of basin morphology on sediment yield in the middle reaches of the Yellow River L U Jin2fa ( Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing ,China ) Abstract :More than 50 river basins with gauging stations were chosen for an analysis on rela2 tionships between sediment yield and basin morp hological characteristics in t he middle reaches of the Yellow River. They have drainage areas ranging from 500 to 2500 km 2 each and can be categorized into 6 types of basins wit h different p hysiograp hical backgrounds : t he loess hilly basins and highly weat hered mudstone & silt stone basins nort h to Wuding River, loess hilly basins in nort h Shaanxi, west Shanxi and east Gansu provinces, loess hill + bedrock mountain basins, bedrock mountain + loess hilly basins, loess y uan basins and bedrock mountain basins. A set of data on river basin morphology were obtained by using morphometric method, including drainage density, percentage of inter2gully area with slope steepness less than 15, re2 lief ratio, basin roughness, basin circularity etc. Different relationships between sediment yield and basin morp hological characteristics were obtained for different types of river basins by plot2 ting and multi2variate analyses. The result s showed t hat t he best correlation exit s between sedi2 ment yield and drainage density, but the relations between sediment yield and the other mor2 p hological characteristics are not as good as expected due to heavy dist urbance of surface materi2 al, vegetation coverage, morp hological develop ment f rom various types of river basins. If tak2 ing the basin types as parameters, different fitness, intercept and slope of correlation lines were observed between sediment yield and drainage density for different types of river basins, show2 ing a control of other basin characteristics, such as surface material, vegetation, landform de2 velop ment etc., on t he relationships of sediment yield and basin morp hological characteristics. The intercepts and slopes of lines tend to increase from loess hilly basins through loess hill + bedrock mountain basins and bedrock mountain + loess hilly basins to bedrock mountain basins subsequently. It indicates t hat basin morp hology is an important factor affecting sediment yield of a river basin but can exert substantial influence on sediment yield of t he river basin only when t he basin characteristics are more homogeneous. Therefore a classification of river basin types is necessary before a correlation between sediment yield and basin morp hological charac2 teristics is established. Key words : the Middle Yellow River ; basin morphology ; sediment yields