中文摘要：

利用“河猫”系统、回声测深仪等测量仪器，对沙坡头水库连续弯道8个典型断面的三维流速、水深、河床高程和悬移质泥沙粒径分布等进行了实测及分析；通过比较2004年、2007年和2008年3次河床高程的实测结果，讨论了这3年来河床冲淤变化情况；为了验证实测结果，利用k-ε紊流模型对沙坡头连续弯道的水流运动进行了三维数值模拟，比较了主流流速和横向流速大小的数值模拟结果和实测结果，得到了较为一致的结果，反映了“河猫”系统能够较为精确地测量天然河道的三维流速。

英文摘要：

Some advanced equipments, such as River CAT, Mini Echo Sounder and Laser Particle Analyzer are used to measure the velocity field, water depth, and suspended sediment particle size distribution on eight typical cross-sections of continuous curves in Shapotou in the Yellow River. Vertical mean velocity, bed level and suspended sediment particle size distribution are studied. By comparing the bed levels measured in 2004, 2007 and 2008, river-bed variation in the three years is discussed. River CAT can measure accurately the three-dimensional velocity of natural rivers.