What is a bankfull stage?
Bankfull: The water level, or stage, at which a stream, river or lake is at the top of its banks and any further rise would result in water moving into the flood plain.
What does bankfull discharge mean?
Bankfull discharge is commonly thought of as the flow that fills the channel up to the top of banks, prior to flooding. For undisturbed, poised streams with wide floodplains, this definition would be correct.
What is a bankfall?
Maximum amount of discharge (usually measured in m3/s) that a stream channel can carry without overflowing. Its frequency of occurrence varies between streams, from a few times each year to once every few years. The water height at bankfull discharge is referred to as the ‘bankfull stage’.
What is Bankfull channel?
Page 1. BANKFULL ELEVATION is the elevation at which water has filled the principal channel and just begins to flow onto the floodplain. BANKFULL DISCHARGE is considered to be the channel forming or effective flow.
How often does Bankfull flow occur?
When flows are greater than this capacity, the stream overflows its banks and flooding occurs. In such streams, the channel is usually big enough to contain a high-flow event that recurs on an average of every 1.5 years (which we call the “1.5-year flood”).
How often does bankfull discharge occur?
While an average return period of 1.5 years is often cited for bankfull discharge, this event can occur at intervals of less than one year to more than a decade.
What is bank full stage?
bankfull stage. The flow stage of a river in which the stream completely fills its channel and the elevation of the water surface coincides with the bank margins. Want to thank TFD for its existence? Tell a friend about us, add a link to this page, or visit the webmaster’s page for free fun content.
How do you determine the bankfull stage of a river?
When the water level is even with the banks, the river is at bankfull stage. And when the water level exceeds the banks or overflows, the river is at a flood stage. As before, earlier and later measurements of the cross-section and the upstream and downstream cross-sectional profiles were used for reference to determine the bankfull stage [32].
When is the Nile River at its bankfull stage?
Butzer and Freeman write that under normal conditions the Nile inundation reaches bankfull stage in the southern Nile by mid-August and in the northern Nile (where the Israelites lived) 4-6 weeks later, which puts its highest level around the beginning of October. When the water level is even with the banks, the river is at bankfull stage.