Hello,
I am reviewing some old work to get a handle on the rational and modified rational method for making hydrographs. The designer first used the rational method using the time of concentration and an IDF curve to find the rain fall intensity of a 10 yr storm to make a hydrograph.
The designer then made a second hydrograph with the same data using the modified rational method. In the second hydrograph, however, instead of using the same time of conentration as before to find the intensity, they used "storm duration" to find it, with their definition of storm duration consiting of 3 times original time of concentraion. Using an IDF curve this gave a much lower intensity. Does this make sense?
I am reviewing some old work to get a handle on the rational and modified rational method for making hydrographs. The designer first used the rational method using the time of concentration and an IDF curve to find the rain fall intensity of a 10 yr storm to make a hydrograph.
The designer then made a second hydrograph with the same data using the modified rational method. In the second hydrograph, however, instead of using the same time of conentration as before to find the intensity, they used "storm duration" to find it, with their definition of storm duration consiting of 3 times original time of concentraion. Using an IDF curve this gave a much lower intensity. Does this make sense?