Weve had some serious rain the last week or so and have experienced some serious drainage issues. Our drive has been washed out in a few places, but I have an idea I wanted to run by the hive. This is the current situation

Here is where the drive meets the parking area. The area is a natural low point, and we get alot of runoff from neighbors whos property is elevated to ours. You can see where Ive started to move dirt around to build up the earth rim for the drive before the last 2" of rain fell.My plan is to dig it out until its suitably low and then build up the ground next to the drive to keep it above grade

Im thinking if I continue to dig it out and then add a plastic or metal culvert through the drive to the field on the other side. The other side is lower, and once its done I will cut a swale in to cut across the field to where the natural swale drains to currently.







In addition Im also thinking about cutting the swale on the side of the drive between us and the neighbor a little deeper to facilitate draining to the culvert I mentioned above, or even adding another one where the other low spots are. Either way Im also planning on beefing up the ground around the drive to make sure its above grade, with a crown in the middle.





Does this seem pretty feasable? The ground is heavy clay and holds water. I plan to aggresively aerate, roll and add comtill this fall to the entire yard. Im also planning on building up the drive with several layers of gravel being brought in as time/money afford it

Feasible? Seems so, as long as you have enough drop. Without the drop, not feasible unless you're willing to pay$$$.

Assuming you have the necessary grade, your plan seems sound. You definitely want a reliable way to shoot grade over that distance to make sure you get a smooth slope with no low spots. Do you have a transit or grade-laser?

Minimum grade to drain water fairly quickly is 2/10th, 1/10th is minimum for all else (non-critical surface water, drainage tiles, etc)...

Your plan seems good since you are helping the water go where it is trying to go.
Obviously helping the natural flow will work.

Your plan seems reasonable to me. Kind of funny, we just went through almost the same issue at the bottom of my parents' driveway. They had just had their driveway redone, so digging across for a culvert wasn't an option. I had suggested putting in a culvert to drain the low spot prior to having it done, but my suggestion was ignored and the water pooled much higher after it was built up. So instead, we extended the french drain I had put in farther up last year so it reached this low spot. Working so far. The most important thing was though, it gave me an excuse to have lots of BX23 time. You're going to have all kinds of fun with that new Kubota.

Don't think I have any pics of the water pooled up. Here's the ditch extending the drain:











Here's how it looks right now:

Here are before pictures from the other day after a heavy rain. You can see where the water just pooled and washed out the driveway. This was before I started digging out where the water is pooling to lower the grade below the drive.





My plan for both cuts is a gentle slope, nothing too crazy. I have a 60" Zero turn so a gently edge would be optimal. Eventually we want to dig a pond, I would probably just use that swale as the overflow, well see how it goes.

The end of that trench is running into the drain I put in last year. We connected this pipe to last year's. Last year's is just mostly covered over by high grass.

I wouldnt think Id need to worry about draining fairly quickly, if I had the culvert in Im thinking it would keep up as the water level rose

I am a civil engineer with more than 30 years experience, so I have dealt with drainage issues many times in my career.  Your concept seems sound, but the potential problem is the size of the pipe and the contributing drainage area.  How many acres drain to the driveway crossing?

At some point in time there will be more runoff than the pipe can handle.  When that happens the overflow will wash out the gravel and may take the culvert with it.  Normally I recommend a minimum of an 18" corrugated metal culvert, then 12" of fill over the top to prevent crushing the pipe, if a heavy truck drives over it.  This may be over design in your case, if there is less than a couple of acres of drainage area.

An alternate design would be to build a hard surface (concrete or asphalt) swale across the drive that would allow surface drainage and would not erode due to water flow velocities.   If you do this, make the grade change at the bottom flatish, and build the swale long enough that the gravel doesn't erode at each end.

That was mostly just a general information comment. That being said, if you have the grade to do it I would go for 2/10ths; note the values I gave are minimums. More grade only hurts when you get to the point that the rushing water causes wash-outs and I don't think you'll have that problem judging by the pictures.

Thank you for the insight. If you can see those last pic of the water after the rain that took hours to build up, so it's not so much running water gathering there as much as it is just lazy accumulation over the course of a few hours.  The total area dumping into that is less than 2 acres

I'm with Steve C.

Is there any reason you can't scrape back the drive, lower the substrate and replace the gravel?

I think lowering the driveway would be a better solution. SteveC wants a hard surface.. I am thinking that if you just made the lowered driveway wide enough you will be ok. That is to say, make a 10' wide section of driveway that is level, so the water spreads out rather than making a ravine.

I dont think its impossible to do, but that would require dropping the drive several feet which I dont think would be practical. Its starting to dry out, Im hoping to be able to finish digging out that low point today or tomorrow

I'm sure it's possible, but I don't think it's necessary and I think there's much nicer ways to deal with it.

If you only have a couple of acres draining to the pipe, just install an 18" CMP and cover it with a foot of material if possible.  That would mean the bottom of pipe is 2.5 feet below the road.  If you do not have sufficient cover, you could use an elliptical pipe or smaller diameter.  That may mean that you will have water overflow the road during extreme rainfall events.  

Regarding slopes...  Grass lined ditches should have 2% (2 ft fall/ 100' run) slope to avoid standing water puddles.  The pipe slope can be 1% (1/8"/Ft) a little more would be better, but inlet control will determine how much water flows through the pipe.

I appreciate your insight and patience with my stupid quesitons, but I have one more.

Would I need a pipe that large? I was originally thinking in the 10-12" size since it takes hours or even a day or so for the water to accumulate there, and it would be easier since the grade isn't that thick? For give me if I'm way off, this is all new to us

No problem asking questions, I am happy to share my experiences.

You can install a smaller pipe, but pipes tend to have debris collect at the mouth and will have gravel and dirt settle in the bottom, so eventually it will stop up and then dam up water and overflow the road, washing out the gravel again.

Another issue is the "design storm"  some day you will have  10 year, 25 year, or 100 year rain event.  When you undersize the pipe the water will overflow the road sooner.  It comes down to  a cost/benefit, spend money on pipe now or replacing gravel in the future.  The limiting factor on how much water will pass through is based on the diameter of the pipe and how much can get into the pipe.  

Engineers, when we get paid for a design, have a responsibility for making sure our design works.  We get sued if we are wrong.  In this case, I am only making suggestions, so it won't be my problem if it fails.  Normally we tend to slightly over design.

Bottom line put in whatever pipe that will fit, but also understand that the smaller you go the higher the risk that gravel will wash out someday.  

What is the height of the top of the driveway relative to the bottom of the ditch on downstream side of road?


ETA:  You could also put 2 or 3 10-12"pipes side by side to increase the flow capacity.  If you do this make sure to lay them with a foot or two apart between each pipe.

By the time I finish grading that spot to make it the lowest point and finish adding gravel to the drive, it will probably be 2' or so. Multiple pipes would be easier and probably achieve the same results without too much extra grading work. Im not sure what would qualify as a 10,20 or 100 year water issue, but in the last 2 weeks weve had over 8 inches of rain

Since you have limitations with cover over the pipe, go ahead and put in smaller pipes.   Just know that at some point in the future you will have to replace the gravel.  maybe only every few years.

A 10 year storm event, has a 10% chance to occur every year.  For central Ohio, that would be 3.5" of rain in 24 hours.  25 and 100 year storms would be more rain.

Yeah our storm last week dumped 5 inches in 24 hours..then weve had spouts of 1" here and there. The problem is there just hasnt been enough time for the ground to play catch up

What about digging out a large dry well system? Im not sure that would work better, but Im considering a dry well setup for our downspouts since the yard is somewhat flat