| Rivers are classified into two types. One is called outer river which flows into ocean and the other is called inner river which can not flow into the ocean but into the desert or lakes. Each river has its own characteristics. Prof. Qian Ning categorizes rivers into four types according to their different features, i.e., migrating bed river, divaricating river, curved river, and straight river, each with it's own distinct features. On the basis of the stability and shifting of rivers, the Ministry of Communications(MOC) generally divides rivers into seven types: (1)deep pool stable reach; (2)shallow pool stable reach; (3)broad-shallow shifting reach; (4)board-shallow migrating reach; (5)slightly curved reach; (6)meandering reach; (7)flood plain reach. This dissertation attempts to study the feature of the inner river's broad-shallow shifting reach(IRBS reach).The whole area of all the inner river accounts for 36% of China's.But its runoff occupies only 4.35%. There are 315 river in Sinkiang Region. All the river are inner river except the Eerqisi River which flows into the Arctic Ocean. The western region are often regarded as infertile, little attention had been paid on the studies and exploitation of the western region, to say nothing of the inner rivers. As soon as the Western Region Development project was brought forth the far-reaching influence of the inner rivers gradually became more important than ever before. The Western Region Development should grasp the great opportunity to enhance the sustainable development in this region. In order to development the agriculture, communications and energy resources, the exploitations of the few but precious inner rivers should be put on the agenda. Therefore MOC hasestablished the plan of the "study on the key technology of the bridge and culvert design in the IRBS reach of the Sinkiang Region" in September 2001(Contract No:2001-318-365-88). The paper presents results and findings of the study on the characteristics of flow and sediment transport in IRBS reach.The characteristics of the IRBS reach are different with river we have known before. The unique properties of the rivers has brought out many new problems needed to be resolved. Unfortunately few studies has been performed to deal with the concered problems and therefore the collection of the related data was very difficult. Based on the study of the previous scholars, the author had investigated 25 typical IRBS reach in the South Sinkiang and the North Sinkiang, and sampled the Hutubi river and Santun river to measuremnet. According to the survey data and the features of IRBS reach, a variable-slope flume experiment system was established for the sediment incipent motion and transportation in high slope bed. The problems were studied and analyzed as follows: (1)the distribution of the inner river, (2)the mechanism of flood forming, (3)the plain at the foot of mountains, (4) the critical value of small scale roughness, (5)static bed resistance and moveable bed resistance in the IRBS reach, (6)coarse sediment incipent motion in the high gradient bed, (7)sediment transportation features in the IRBS reach, and (8)the physical model design of the movable bed rivers. The major conclusions are as follows:(1)The divided line of the outer river and the inner river starts north from Daxinganling to the east-north, west-south direction, passes through the Yin Mountain, the Helan Mountain, the Qilian Mountain, the Riyue Mountain, the Bayankala Mountain, the Lianqingtanggula Mountain and the Gangdisi Mountain, and finally reches China's west, Tibet border. Most inner rivers are located in Sinkiang,, Hexi aisle, Caidamu basin, Inner Mongolia and the north Tibet. Some local inner rivers locate in the Song Nen area. The IRBS reach mostly lie on the erosion and sedimentation fan plain at the foot of mountain. The depth of the fan usually is measured tens of or even hundredsof meters.(2) The inner rivers are mostly seasonal ones. The factors which influence the characteristics of the IRBS reach...
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