Hello ,
I want to do runoff modelling using NRCS CN method, but to start with I am not clear about the idea of how to determine the antecedent moisture condition. In papers people have choose AMC II values in the table by Chow 1998. I also want to determine the curve numbers using the AMC. Kindly tell me how to proceed for the determination of curve numbers?
Apart from this I have information on soil texture according to which the soil is ranging from fine , fine loamy , clayey and sandy to coarse sandy. I have soil depth information in terms of low medium and high.
Following YouTube lectures are sufficient for curve number method and example:
https://www.youtube.com/watch?v=B9Wgcm7RqGc
https://www.youtube.com/watch?v=P0-DDESgjXY&t=113s
Good and useful question....
this article may be of your use
SWAT application to estimate design runoff curve number for South Korean conditions
Dear Sadiya,
Indeed the curve number (CN) depends on the Antecedent Moisture Condition (AMC). The National Engineering Handbook (section 4, NEH-4) used to provide three tables with CN values depending on AMC (I-dry, II-average, III-wet). Later on, other studies derived relations between CN and AMC. The next step is to determine AMC. Several studies investigated and determined relations between AMC and antecedent rainfall in the previous days and hence derived equations between CN and antecedent rainfall amounts. See attached paper for an example.
Regards,
Martijn
Hello Martin Sir,
How to know in which AMC category my watershed will fall in, whether it will falll in AMCII or AMC I?
Dr. Khan, the attached files may provide you the desired information.
In the paper I attached the authors derived direct relationships between CN and antecedent rainfall amounts, so there is no need to firstly determine the AMC category. Good luck!
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