Drainage design

[tanak]

Hi Dr. Quek!

1. How to determine appropriate width of drain to be used?
2. How to determine starting depth of drain?
3. What are the gradients of drain to be used for different width of drain?
4. What is meant by overland flow? How to calculate it? Can you give some examples.
5. Are there any standards for my questions above (as in MSMAM)?

Tq:)

[drquek]

1. How to determine appropriate width of drain to be used?Most engineers used the Manning's Equation for this purpose. But the best tool is actually HEC-RAS which I used for my work. It allows you to quickly estimate the size of drain to be used.
2. How to determine starting depth of drain?Using HEC-RAS you can try different sizes quickly.
3. What are the gradients of drain to be used for different width of drain?same as above
4. What is meant by overland flow? How to calculate it? Can you give some examples.Please refer to MSMA the chapters on Rational Method. I am now in Singapore and I don't have the manual with me.
5. Are there any standards for my questions above (as in MSMAM)?
Yes, these are covered in MSMA in different chapters. So you need to understand them before you know how to apply.