Drainage of narrow gravel drive

[mikec1972]

Hi, i am building a narrow 3.5m wide driveway (30m long) across a farmers field which links a local road with a barn conversion, and have a question about how best to drain the road, there are no outfall points nearby.


For 3.5m wide gravel driveway in a fairly free draining area (a farmers field driveway leads to barn) could we use simple over the edge drainage into adjacent grass verge (set the Finished edge road level at say 40mm higher) or would a french drain to soakaway be better.
I am not sure as i would imagine a gravel driveway would be fairly free draining anyway and given that the driveway will only be 3.5m wide with planting either side would it be more economical to just crossfall (or camber?) the road and drain straight to grass verge at the side. I suppose if i camber the drive then there will only be a width of 1.25m draining over the edge to each of the grass verges which are fields. I'd have thought 1.25m of width/linear metre of gravel driveway would be enough to go over the edge and drain into adjacent soil without having to worry about a french drain or am i wrong? Your help would be much appreciated.

Cost is an issue and i have noted that for most of the local authority roads nearby there are no gullies present and the surface run-off just seems to go over the edge into verge, there are no watercourses or ditches nearby.

[GB_Groundworks]

id excavate it, theg dig to french drains down each side and try find somewhere to drain it to, if its a field it will have drainage maybe old 3" clay drains or suff drains made of stones, or leave the french drains as soakaways, have the drains a good 400mm lower than the subbase fill with clean stone upto the level of the bottom of the mot then mot over it,

not point cambering mot as it wont run the rain off and you'll get gravel migration from centre to edges