French drain for the whole lot?

[dodge man]

Look at it this way, you really don't want to handle all the water from a large rain do you? Its after the rain you want to dry the ground out, so I wouldn't worry about a pipe much bigger than a 6". If you want the pipe to handle all the water from a storm, you will have to do a little engineering and figure out how much water you need the pipe to handle.

 

[dstig1]

Yeah no kidding.... You aren't talking about a french drain. Those are to remove subsurface water and water that leaches down into the ground. You are talking full on culvert here...or creek...

It really sounds like you need to dig out a rather large swale and line it with rip rap or something.

 

[AHNC]

Depends, as has all ready been pointed out, upon how much you want to get rid of. 4" has a cross sectional area of 12.75", 6/28" and 8/50". How much grade do you have. From the base of the foundation to the bottom of the trench, assuming you make it level from foundation to drain. I live on a grade and the neighbors behind and downhill from us dug a 3'W X 7'D trench around the uphill side and the lateral to grade and filled this thing with about a million yds (slight exaggeration) of rock in the ditch. i think you have the right idea, watching it for the winter. Don't forget clean-outs about every 50'. you will be thrilled with the performance the first couple years and with the silting, you will be less and less happy over time. Are you running this to grade?

Just remember all you "live free or die" guys that being from Massachusetts, I have to deal with ALL of your darned run-off Keep us posted how it works out!