stormwater running over gravel road before getting conveyed? ok?

[meatymatt]

The norm is to have a swale on both sides of the road and crown it. What about having the road slope to one side and eliminate one swale. The stormwater from adjacent land would travel over the road before it gets to the swale, not the best idea, but for a small road with "gentle" slope, a "tight" gravel surface, and a yearly maintenance plan would this plan work or is it doomed from the start?

Proposed Scenario: Grade of road and adjacent land is approximately 1.5 - 3%. Cross slope of 20' wide gravel road 3/8"/ft from left to right. Provide swale on right side of road (downslope) to catch stormwater and sediment from road.

Trying to minimalize and eliminate the need for 2 swales and possibility of structures to convey the flow under the road. Any publications or experience on this subject?

Thanks.

 

[cvg]

usually prefer road cross slope to be the opposite direction as the prevailing land slope to minimize the amount of water running across the road. otherwise I would not recommend it

 

[qrb613]

How many acres would be draining across the road at any one place?

 

[meatymatt]

GRB,

Not much. Off the top of my head, the road is 700 ft long. For the first 500 the water shouldn't cross the road at all. The road is pretty much perpendicular to the contours. Then between the 500 and 700 ft points, approx 20000 SF of grassed land is sloped at approx 3% towards the roadand will cross it. I could place the swale on the upland side but would need driveway culverts and probably another culvert to transfer water to low side at the termination of the swale.

 

[civilman72]

I design a lot of gravel roads and always try to keep the ditch on the uphill side.

How much annual precipitation in your area? Any issues with ice/snow?

Have you thought about how much water will be conveyed onto the road from the uphill driveways?