Help With Driveway Drainage

[UOFan]

Hi everyone -

I have some time off and would like to fix my crush-and-run driveway’s drainage. Water flows across the driveway downhill and is washing out the grass on the downhill side.

My main idea is a really long French drain system with multiple inlet catches on the downhill side. Here are some photos that I just took:

This first photo shows the driveway leading to my house. The left side is the downhill side, you can see it’s washing the grass away. The right side is also slightly washing sand onto the driveway. There is a berm on the right side you can see in later photos.

My idea is to put a French drain along the blue line.

In this photo, the purple “squares” roughly represent where I would put inlet catches/grates to allow the water to flow into the drain pipe.

Here is the view from the downhill (end) of the driveway. The blue line is the potential French drain. It would also serve to catch runoff from my carport roof (no gutters).

Here is a wider photo that shows the berm on the right (uphill) side.

Finally, here is a top view of the driveway.

I am happy to hear all your opinions and comments. Thank you for any advice.

Bryan

 

[2manyrocks]

Is water coming down the driveway and then flowing into the grass where the blue line is located because the grass is downhill?

Would it be possible to divert the water off the driveway with a simple dip and avoid all the excavation for the french drain?

https://dirtandgravel.psu.edu/wp-content/uploads/2022/06/TB_Broad-Based_Dips.pdf

 

[Mud2Money]

I wouldn’t put a French drain at the low side. To fight water you have to begin at the source. The sooner it’s caught and diverted the better.

 

[UOFan]

Is water coming down the driveway and then flowing into the grass where the blue line is located because the grass is downhill?

Would it be possible to divert the water off the driveway with a simple dip and avoid all the excavation for the french drain?

https://dirtandgravel.psu.edu/wp-content/uploads/2022/06/TB_Broad-Based_Dips.pdf

Yes, water tends to flow towards the blue side because it is the downhill side. The water then runs along the blue line and laterally off into the grass.

Where would you recommend that dip divert the water to?

 

[Egon]

Consider a shallow drainage ditch on either side of the road. ??

 

[2manyrocks]

Yes, water tends to flow towards the blue side because it is the downhill side. The water then runs along the blue line and laterally off into the grass.

Where would you recommend that dip divert the water to?

You'd have to study the elevations to find somewhere to divert the water so it doesn't run towards your house. I assume the berm was made to divert water from flowing down the hill onto your house and yard. Perhaps you could divert water into the berm?

Rather than excavating to make the dip, I'd think about bringing in a load of gravel to compact to make one.

 

[ljgordon]

First, I would gutter the house and shed to divert the water away from the driveway. Then I would plant some hardy ground cover along the driveway.

 

[dodge man]

You may need to divert the water, that might be a problem, but it seems like your grass isn’t growing very well anywhere and doesn’t have anything to do with erosion. When it rains that probably tells the story on if anything needs done.

 

[2manyrocks]

A gutter on at least the house side of the carport would be easier to install than digging a french drain in that area and keep water from running onto you walking in and out of the carport.

dodge man just gave you a very practical tip. The easiest way to see where the water is coming from and going is to go outside during a pretty good rain and watch to see how the water is flowing. You might place some marking flags in the ground during a rain to mark the spots where you want to make changes. Finding the right place to divert water can make a big difference.

 

[EddieWalker]

Every French Drain will fail. It's just a matter of time. For that reason, I'm not a fan of them.

A ditch works 100% of the time, forever. I think the biggest hurdle in digging the ditch is getting started. Once you start moving material, shaping it so you can mow it and make it look nice, it becomes a very doable project.

I don't believe the grass isn't growing because it's getting too much water next to the driveway. I'm guess it's not growing there because people drive over it, but it could also be that your soil is just really bad there. Either way, I would put up a barrier to stop people from driving over it, like a big boulder, or a few shrubs, or a temporary fence. Just a stick with a string will work. Then I would spread some top soil, through out some grass seed, and water it every day.

 

[Gator6x4]

From the photo's you provided it appears you have more of a soil problem than a water problem. Most states have and offer free soil testing and provide what nutrients that are needed to grow grass.

If me I would delay the French drain project and get a soil sample and check for Grubs. Your photo's do not show water etching or trenching in the barren spots just no grass. Brown spotting, Grubs or soil nutrient deficiency will give the visual appearance, depicted in the photo's provided.

 

[UOFan]

You'd have to study the elevations to find somewhere to divert the water so it doesn't run towards your house. I assume the berm was made to divert water from flowing down the hill onto your house and yard. Perhaps you could divert water into the berm?

Rather than excavating to make the dip, I'd think about bringing in a load of gravel to compact to make one.

Yes, you assumed correct. The previous owners dug a trench and berm on the uphill slope to prevent washout of the driveway. I will look into the dip diverting flow into the berm/trench area. Going to go take some quick eyeball measurements.

I appreciate all the advice. Yes, the grass is also being killed by us driving over it. It’s going to rain today, I will be closely watching the flow of water.

Really I’d like to slightly expand and line the driveway with some sort of concrete block (as you guys have suggested), but I didn’t want to bring in multiple loads of material until the drainage was addressed.

 

[ruffdog]

The OP's property looks just like up north in WI with the evergreens and the sandy soil that grass doesn't grow good in. It looks like you don't have a good turnaround area and might be why you drive on the lawn? I'm tending towards getting a load of gravel to give the drive more height and work on the turnaround. Then get a bunch of rich composted top soil to match the level of the yard with the higher gravel drive. Plant grass in that rich soil and the grass will help control the water. Yes, soil test to help the rest of the yard. I'm just not seeing the evidence of a big erosion problem.

 

[UOFan]

Thank you everyone for the input. This is exactly why I posted this here, because everyone has great input. Here is my current new plan:

0. No French drain on downhill side.

1. Expand the driveway on the downhill (right) side for a turnaround. To do this I will create a border with cinderblock, keeping the elevation slightly higher than the left side of the driveway. Basically will create an 8" retaining wall, then fill with crush and run.

2. Identify 2x locations for creating a dip to divert water from the driveway to the left (uphill) side. This will allow me to divert it into the already established trench the previous owners had dug. The trench needs work to become a swale or culvert, but the massive upside of diverting water here is that there is a viable outflow into the woods.

3. Remove the berm on the left (uphill) side of the driveway, and further expand the driveway to the left, butting up to the trench.

4. Still working through this, but this step would involve putting in an 110' // 30" retaining wall against the uphill slope (left boundary of driveway). I'd look at having at improving the drainage system to prevent the water from undercutting the retaining wall.

 

[2manyrocks]

A simple, reliable and inexpensive method of measuring changes in elevation is to use clear vinyl tubing to make a water level. There used to be a company called Fi-Shock that made a couple of tubes with graduated inches on them that worked really well for water levels, but I don't think they make them anymore.

I'm not a fan of cinderblock borders. Seems like they all look terrible after a few years unless they are professionally laid on a foundation.

If the previous owners went to the trouble of adding a berm to a swale/ditch, that suggests they sometimes had more water runoff than the ditch could handle. May 2010 is infamous in Middle Tennessee for a very unusual amount of rainfall that happened suddenly causing widespread flooding damage. It may only happen once in a blue moon, but sometimes water flow can be unexpectedly heavy. So I'd be cautious about removing the berm that might have been installed for those once in a blue moon runoff situations.

 

[UOFan]

A simple, reliable and inexpensive method of measuring changes in elevation is to use clear vinyl tubing to make a water level. There used to be a company called Fi-Shock that made a couple of tubes with graduated inches on them that worked really well for water levels, but I don't think they make them anymore.

I'm not a fan of cinderblock borders. Seems like they all look terrible after a few years unless they are professionally laid on a foundation.

If the previous owners went to the trouble of adding a berm to a swale/ditch, that suggests they sometimes had more water runoff than the ditch could handle. May 2010 is infamous in Middle Tennessee for a very unusual amount of rainfall that happened suddenly causing widespread flooding damage. It may only happen once in a blue moon, but sometimes water flow can be unexpectedly heavy. So I'd be cautious about removing the berm that might have been installed for those once in a blue moon runoff situations.

I think this is the tipping point project to buying a tripod laser level for me, we will see.

Regarding the cinderblock, that was a typo. I plan on buying come retaining wall block, a bit more visually appealing. I agree cinderblock walls look bland.

Great point about the berm, I hadn’t thought of that. I’ve never seen actual flowing water in the trench, as my soil there is incredibly sandy. But we are in hurricane territory. I am planning on having some sort of elevation change between the trench and the driveway, maybe I’ll do a similar mini retaining wall about 12” higher than the trench.

It’s pissing rain here and will continue throughout the weekend, it’s a great time to study the flows of water around that area.

 

[2manyrocks]

Unless things have changed from when I looked at outdoor lasers, it's not so easy to see lasers outside and the ones you can see are expensive. If the tripod laser is just a hair off level at the tripod, the resulting error will be magnified.

Water seeks its own level. Pretty hard to mess up a water level.

 

[nyone]

Anywhere you feel the need to collect surface water and direct it away I would try to do that with a swale first. Pipes clog, are expensive and way harder to maintain than a slight swale.

I do agree that you shouldnt have surface water going towards your house.

 

[Rockbadchild]

I agree as well, especially around a driveway, undergrounds pipes get run over they collapse and plug up over time ...

 

[Eagle1]

Let alone the clogs from grass clippings, pine needles, leaves and random trash people throw out of their cars. I find that anything less than 24" (36" better) diameter clogs at some time the smaller the more it happens and you ALWAYS have to clear it in rain storm or deal with even more damage. All it takes is a stick and some leaves, lots of both out here.
A swale or ditch is easy to get flowing again, clogged pipes/culverts are way more difficult.