HEC CENTER HOME PAGE:

http://www.hec.usace.army.mil/default.html

HEC-RAS MODEL: to determine river surface profile

http://www.hec.usace.army.mil/software/software_distrib/hec-ras/hecrasprogram.html

HEC-HMS model (hydrological modeling system: to determine rainfall runoff

http://www.hec.usace.army.mil/software/software_distrib/hec-hms/hechmsprogram.html