For basin scale water balance study, I used SWAT model and result is impressive. I studied for Ken river basin of India of size approximately 27,000 km2. What is your basin area, if that basin is not snowfed, I recommend to use SWAT model for water balance study.  

Definitely, SWAT is a very good model, it Runs into the ArcGIS and QGIS software. Other options: TOPMODEL into the Saga GIS. According to your needs, I could recomend you other model.

Thank you. i needed to compute for two separate periods.(4 years for each period) for a basin that is just approx 12000km2. 

as suggested use Soil and Water Assessment Tool (SWAT) 

Dear All,

Yea SWAT model is good for non snow and non ice fed river basin. Does any body knows about the SWAT model (if there is integrated), which includes the amount of discharge from melt of snow and ice.

Thanking you,

Mohan, there is one called WIMMED, but I have not worked with snow models, and I can not speak as an insider about this theme. 

http://www.ugr.es/~herrero/

I think this file can help you...

Dear Oliver,

The links looks like interesting to me. I liked it so much. But, have to go through this in more detail. I think this will certainly help me.

Thank you for suggestion.

Regards.

Mohan

Dear Adel,

Thank you very much for the sharing the important documents related with water balance study of lake and reservoirs.

Hope this document will be useful for me.

Thank you

Mohan

SWAT model is good.

Try Mehran model which is more user friendly and will give you precise results. If you need model, I can prove you free of cost through ResearchGate or directly because it was developed to serve worldwide for present and future food, fiber and fuel security.

I will need  the model Khalifa

send me your email on reply i will attache the model.

my email: [email protected]

Dear Khalifa,

Please send the model me too. I have already send you a email.

Thanking you,

Mohan

I tried to send model exe but Gmail blocked due to security reasons