Methods for calculating the runoff from a watershed as a part of water balance study.


Hi this is Pandit Pandit from India and I am working in watershed development project. Recently we have undertaken a watershed of 1000 hector for development. We need to calculate the total runoff from this watershed as a part of water balance study. I am looking out for some good and reliable methods to estimate the total runoff from this area. The average rainfall of the region is 2500 mm and the soil is sandy loam to loam , with slope of 5 to 30 %.. 

Hope to get some good suggestions, thank you.



Saladin Ahmadi
Hydrocad is the best solution with minimum requirement of data and more accuracy
Govind Bharad
For remote places in the watershed, it is better to use the flume of appropriate size attached with the stage level recorder with mechanical clock, calibrated for daily or weekly readings.
Pandit Patil
Just to inform you all, we will be using the software (Hydrocad) for calculating the runoff from the watershed, which we feel is the best accurate method right now.
Pandit Patil
Thank you @ Mr. Park, Carol, Kelly, Ms. Judith and Mr. Scott for your very good and reliable suggestions. Definitely I will try a suitable one. In case needs extra information will be back to you....thank you very much once again.
Scott T
Selection of the Appropriate Method for Calculating Runoff ##
Judith  Braker
We have used HydroCad and its easy way and much accurate too.
Kelly P
Have you heard about HydroCAD ?
This is an excellent way for calculation the runoff, I know calculating runoff correctly is the key factor for the water balance study. I suggest you to read about HydroCAD and try to use it. The link for the calculator is
they use rational method, you must try.
carol g
1. Rational Method
2. Peak Discharge Method
3. Tabular Method (TR-55)
4. Unit Hydrograph Method
Park Wan Wan
At first I must say watershed development is a work of dedication. I have visited several w/s in India during out study tour. We just fell in love with the check dams constructed by some local means like VANAARAI dam etc. As far as your question is concerned, I suggest to have a spot discharge measurement device as the area is very big. Some of the spot discharge measurement devices are,
1. volumetric gauging
2.float gauging
3. impellor current meter
4. electromagnetic current meter
5. ultrasonic (doppler) flow meter
6. acoustic doppler current profiler (ADCP)
7. dilution gauging
But all these devices are used for a stream flow and must be available in market.
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