Drainage area criteria

[efejr28]

I believe a good grading desing should start by defining drainage areas for the project; or "influence areas", where the high and low points are determined for the streets. Just want to ask for a few extra tips on the criteria or guideline to create or define this areas. Things to have in mind....

Thanks a lot!
pD

 

[gbam]

Hello efejr28,
You seem to be on the right track. I usually look at the "big" picture from a drainage point of view. This is because you can fill or cut to obtain the desired final grade for the project site. We have modified the land sooo much that when older topo is examined it is hard to beleive there was a canyon or mountain in that location. So from a drainage engineer's pov, I search out points of concentrations both upstream and downstream from the project site. I evaluate the existing condition drainages and design to meet them (if necessary). Looking at the big picture always seems to help!