Rational formula - strange resulting Qp
Rational formula - strange resulting Qp
(OP)
Hi,
I'm estimating peak discharge values for two basins. One is the other's tributary. One has an area of 64 km2 and the other 0,7 km2.
For the bigger basin (Stream A) I obtain reasonable values (167 m3/s) according to other methods (SCS, Giandotti), but in the small tributary I'm getting an anormaly huge value (46 m3/s). Can someone help me find what am I doing wrong? I believe the error is related to the Rainfall Intensity because in the SCS method I obtained good discharge values (4 m3/s).
I've uploaded a small .doc file with the calculations.
Thanks and apologize my weak English.
Pedro Santos
I'm estimating peak discharge values for two basins. One is the other's tributary. One has an area of 64 km2 and the other 0,7 km2.
For the bigger basin (Stream A) I obtain reasonable values (167 m3/s) according to other methods (SCS, Giandotti), but in the small tributary I'm getting an anormaly huge value (46 m3/s). Can someone help me find what am I doing wrong? I believe the error is related to the Rainfall Intensity because in the SCS method I obtained good discharge values (4 m3/s).
I've uploaded a small .doc file with the calculations.
Thanks and apologize my weak English.
Pedro Santos





RE: Rational formula - strange resulting Qp
secondly, using rational method for a 64 square kilometers area is not appropriate and should not be done. Suggest a better method would be to use regression equation based on similar large watersheds
thirdly, your basin may produce more runoff during a 24-hour or longer storm.