There are different types of hydrological models corresponding to Rainfall Runoff and Snow & Glacier melt runoff. Basically you can apply Curve Number, PRIMS, SWAT and SRM models. These models depend on your Temperature, Rainfall and Area. Snowcover fraction of the total area in case of Snow/Glaciated terrain.

http://water.usgs.gov/software/lists/surface_water

please find some GUI based models (softwares) in the above link

In river modeling if you are going to perform  river discharge modeling using public domain software, HEC-HMS would be one of the good choice and for flood inundation modeling HEC-RAS. however among licensed software i would suggest you to use MIKE series or Flood Modeler Pro.

Arun, Pl have a look at this paper, if it would help you in some way.. Best,

Article Distinguishing human and climate influences on hydrological ...

I will suggest Mike 11 from the Danish Hydrological Istitute. However u would have to get the license for that. I'm sure for academic purposes you might get a student version from them for free. But you can also use HEC-HMS. For your upstream runoff modelling, you can also use SWAT to provide you with your upstream input data (thus if you don't have any upstream data measuring point)

Dear Asare Gyimah,

                                     Many thanks for your help.

Regards

Arun

Respected Sir, there are many hydrological model but for your above quire, I personally feel MIKE 21 will be the best as it can be used for both river & estuaries purpose, but for that we need to calibrate and validate model. For that we need Hydro-meteorological,Meteorological Data etc.

IntErO software (2011)

www.agricultforest.ac.me/Spalevic/IntErO

There are many mathematical models for calculation of the quantity of sediment. One of these is the analytical model of Prof. Gavrilovic for determining the intensity of erosion and outflow for a natural river basin. Software package "IntErO" (Intensity of Erossion and Outflow) incorporated and upgraded the first program generation "River basins" (Spalevic, V et al 2000.) and "Surface and distance measuring" (Spalevic V. et al, 1999). The software was created in the program language Borland Delphi and it works with the Windows operating systems. For user interface and reports, choosing between Serbian and English language is possible.

Velibor SPALEVIC: References (Bibliography)

www.agricultforest.ac.me/Spalevic/Reference

IntErO software (2011)

www.agricultforest.ac.me/Spalevic/IntErO

Surface and distance measuring (1999)

www.agricultforest.ac.me/Spalevic/Surface

River basins (1999)

www.agricultforest.ac.me/Spalevic/River

You can use the Global model of the CMAGREF (institut of reaserche in Franc) the GR model . You have annual model GR1A THE monthly model GR2M. THE Daily model GR4j and the hour model GRH. This model is free and very easy for appliation 

Hi,

If you are interested primarily in predicting daily river flows above the tidal limit, you could use PERSiST. The model has been applied at multiple catchments in Europe, North America and India

Futter, M.N., Erlandsson, M.A., Butterfield, D., Whitehead, P.G., Oni, S.K. and Wade, A.J., 2014. PERSiST: a flexible rainfall-runoff modelling toolkit for use with the INCA family of models. Hydrology and Earth System Sciences, 18(2), pp.855-873.

Futter, M.N., Whitehead, P.G., Sarkar, S., Rodda, H. and Crossman, J., 2015. Rainfall runoff modelling of the Upper Ganga and Brahmaputra basins using PERSiST. Environmental Science: Processes & Impacts, 17(6), pp.1070-1081.

dear Arun,

try with MIKE 11, paper in attach file may help you

best wishes