中文摘要：

山区卵砾石河流在西部山区广泛分布，其阻力关系是认识水流泥沙输移规律、模拟山洪演进过程的制约因素。通过在四川龙溪河的现场观测，获得了水力学、泥沙、地貌等要素的数据，分析了阻力系数与卵砾石特征粒径、坡降、流量、河床结构强度等参数的关系，检验了已发表的多个山区河流阻力公式的适用性。结果表明，由于山区卵砾石河流存在不同发育程度的河床结构以及卵砾石的部分可动性，阻力系数与山区河流的流量、坡降、河床结构发育程度参数等有密切关系；Rickenmann及Ferguson阻力公式在龙溪河具有较好的适用性。本文仅仅是山区河流阻力的初步成果，今后将进一步开展阻力关系的深入研究。

英文摘要：

Gravel-and boulder-bed streams are widely distributed in west China＇s mountainous areas. Their flow resistance relations are the basis of understanding the flow and sediment transport law during the pro- cess of flash flood. This paper presents an analysis of field data collected in the Longxi River, Sichuan Province. The relationship between the Manning coefficient and sediment characteristic size, flow slope, flow discharge and riverbed structure intensity St is explored. Several published flow resistance equations es- tablished for mountain streams are examined. The results show that the Manning coefficient is closely relat- ed to sediment size, Sp, slope, and flow discharge in the Longxi River. The Rickenmann and Ferguson equations are applied well in this river. Future analysis with more field data will be carried on.