the small river valley 基本例句 小流域 This small drainage area will not be influenced by the Siberian cold current.这小流域不会受到西伯利亚寒流的影响。 And the method is verified in the calculation of ravine density in a small watershed of the Yellow River basin.并以黄河流域某小流域沟壑密度的计算作了实例验证。