catchment area 300 hectares

Question

i want to design a trunk storm line with catchment area 300 hectares. i think we should not use Rational method. what other calculation methods i can use in civil storm? .

Craig Calvin · Accepted Answer

CivilStorm let's you choose between three different Active Numerical Solvers, each offers different runoff methods for catchments. 
 You can change the Active Numerical Solver by opening the Analysis menu, select Calculation Options, and then double-click on the active solver (red check mark on the icon). 
 The following article discusses the differences between solvers. 
 SewerCAD (GVF Convex Solver) vs. SewerGEMS/CivilStorm (Implicit and Explicit Dynamic solvers) vs. StormCAD (GVF Rational Solver)?

Jesse Dringoli · Answer

To add to Craig's response - the notable runoff methods with the Implicit and Explicit dynamic solvers in CivilStorm are the Unit Hydrograph Method, EPA-SWMM Runoff Method and the Modified Rational Method. 
 
For a large catchment area, the first two might be best. If you are submitting to a certain reviewer/agency, you may also want to check with them if there is a preference.