hi I'm not a hydrologist but i'm working on rainfall event simulation on a wadi stream. I have a hydrograph showing only the water height( or depth) of the wadi at the time of the event and no rating curve graph. is there a way for me to estimate Q from water height H through time?
thank you
Without rating curve is difficult, and flows in most streams can vary over several orders of magnitude from low flows to extreme floods. Flow as it changes in height, is a result of the changes in cross section and changes in mean velocity. Channel gradient and roughness (Mannings N - friction) influence velocity. If flow is contained below bankfull depth, mean velocity icontinues to increase with stage, but as stage increases onto floodplain, the mean velocity on some streams declines.
Wihout a control such as weir or flume, calculations can be made with substantial more detail beyond height. If all available on ungaged stream is only height (depth), I would not attempt without substantially more information on channel.
Just to support William, you need to have (or at least an acceptable estimation) the values of Manning's equation variables to be able to calculate Q.
If you do not have any information and have to roughly estimate Q, maybe you assume that n=0.05 for natural creek/river, the slope of 0.001, the side slope of 1:10 for a triangular cross section. In this case, by having only water depth you can approximate Q.
But please try to gather all observed information to have accurate estimations.
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