標準號：IS 2912-1964
發布日期：1965/3/1 12:00:00
實施日期：1999/12/31 12:00:00
適用范圍：This recommendation deals with the methods of determining the slope and cross-sectional area of water flowing in open channels, and of computing the discharge therefrom. The method provides an approximate estimate of the discharge in the streams and is used when estimation of discharge by more accurate methods like the velocity-area methods is not possible. The slope-area method can be used with some degree of accuracy only in channels having relatively coarse bed material; this method may also be used in other cases, such as alluvial channels subject to the acceptance of larger errors involved in the selection of the value of the rugosity coefficient 'n'. It is, however, not desirable to use this method in the case of very large channels or channels with high sediment concentration. This recommend-ation deals only with ad hoc measurements of discharge and should not be employed for establishing rating curves.