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View Full Version : No drainage...standing water.


rywnygc
01-25-2012, 10:29 AM
I just picked up a customer that has a bad drainage issue (sorry, no pics yet). Her back yard is about 40% covered in 2-3" of standing water from late fall to late spring. The neighborhood is in the city and there isn't a means of running drain tile, as there is nowhere to run it to. Top dressing isn't an affordable option for her. I am considering installing dry wells. I plan on using a 12" auger and drilling 36" down and filling them with either sand, or #2 stone. I will start with about 8 holes.

If you have experience with this, please give me some feedback on the results and the conditions you started with.

Any other ideas can be discussed as well. Thanks!

ralph02813
01-25-2012, 02:02 PM
I just picked up a customer that has a bad drainage issue (sorry, no pics yet). Her back yard is about 40% covered in 2-3" of standing water from late fall to late spring. The neighborhood is in the city and there isn't a means of running drain tile, as there is nowhere to run it to. Top dressing isn't an affordable option for her. I am considering installing dry wells. I plan on using a 12" auger and drilling 36" down and filling them with either sand, or #2 stone. I will start with about 8 holes.

If you have experience with this, please give me some feedback on the results and the conditions you started with.

Any other ideas can be discussed as well. Thanks!

I have a very similiar customer, when I tried to dig the first hole I thought I hit cement, then realized it was about a 4 inch thick layer of clay. I filled it with chippings the following week it had a dry circle about 3' around it. So your sand idea should work great if you have the same problelm.

Dr.NewEarth
01-25-2012, 03:13 PM
Dry wells. French Drains. You need to figure out the amount of water that's standing and at least make the dry wells total area the same size or larger if possible.

I recommend digging down and making a big pit at least 18 inches (36?) deep and lining the entire hole with landscape fabric so it drapes right over to the top at grass level. The fabric prevents the fine particles of silt from locking up the drainage ability of the gravel. If you don't do it properly, the problem will return.

Then lay about four inches of clean three quarter inch crushed gravel in the bottom of the hole. Walk on it or tamp it down to help with the settling.

Next lay out some pvc with the holes facing down in the hole. You can use more than one pipe if you need/want to. You can also get pvc in a sock that prevents more of the silt from clogging your drainage system. Use the landscape fabric lining the hole and the sock for really heavy clay soils for extra protection.

Cover your pvc with a few inches (or more) of gravel so the dry well/French drain is at a minimum, the correct area for the expected amount of standing water to sit in below ground...and then wrap over and overlap the landscape fabric so that the whole thing is covered like a burreto.

You could then top the fabric with sand if you want, but you will need about four inches of soil on top so the grass grows properly.

Perhaps if you draw a picture it will help to understand the calculations.

Lastly, I would aerate and remove the plugs from the lawn. Top dress with sand so it fills the aeration holes.

Is there a slope in the lawn? You could add a glued T to the pvc that comes up to the grass level. Glue a screened drainage inlet at soil level, which will help with the problem. If you do this, you must also put landscape fabric as a filter over the hole so that debris and silt doesn't get into your French Drain holding area and plug up the system.

We get alot of rain where I am, and this is the recommended method from our Landscape Standard.

When you price this out, consider that you don't know what you will find below ground. There could be a huge boulder or tree roots or clay that adds alot more labour time to the project.

There will also be alot of soil from the excavated French Drain hole that needs to be disposed of. Can you salvage the top 4 inches of top soil?

Also, when we do this we lay plywood and or tarps on the edge of the excavation to protect the lawns. You can cut the turf and turn it upside down onto the tarps so that you can re-use it. If it is really wet or regardless of that, you may need to lay out more plywood or boards to use as an access sidewalk across the grass area. You don't want to destroy the rest of the lawn with deep wheel barrow ruts and footprints. That would also cause your soil to be compacted more, and could lead to weed problems like plantain and dandelion.

rywnygc
01-25-2012, 04:11 PM
Thank you for your informative reply. I have used the plywood trick plenty of times. I never actually thought of aerating and back filling with sand, seems like a great idea! Thanks again.

sven1277
01-27-2012, 07:31 PM
I would suggest using the flo-tec dry wells. They hold about 50gal. They do a better job then open graded stone alone.

BFuller
01-28-2012, 11:35 AM
I'm dealing with a similar problem with a residential site we are in the final stages of installing.

There is a raised area that is retained by a pored concrete wall, faced in cultured stone. The areas where the new turf meets the bedding has started collecting water and there is a 4-6 ft. wide area of the turf, all along the bedding lines, that collects water like crazy. Unlike all the rest of the turf we installed in the other areas of the yard that are looking nice and green and lush, this area just won't drain properly. At one point, we even witnessed upward bubbling from the turf in few spots where there is standing water and in two other spots there was air trapped under the turf causing an actual air bubbles! I've only seen air bubbles under turf one other time in my 20 year stint in landscaping and that was in a commercial area where there was known methane coming from a re-developed landfill site. However, when I cut the bubbled turf with a sod knife, there was no smell of methane and there have been no air pockets develop since, and that was two months ago.

We're going to be tackling this drainage problem in 10 days when the property owner is back from holidays. I think we're going to go in and dig a drainage trench right through the middle of the waterlogged area, do a drain system with perforated pipe, fabric, gravel, etc. and "daylight" the drain through a low point in the poured concrete wall. Top the drain/waterlogged area with a 60-70% sand mix and re-turf the area.

Also, I'm going to spend the extra couple of hours it's going to take and remove the plants from the bordering bedding areas and give the beds a good tilling.

Here's a good one... In going through some video footage that was taken when i was off-site and the soil was being installed, I noticed that one of the guys was using the bed line as his repeated line of delivering buckets of soil to the planting beds. He was using a Bobcat MT-52 track machine and even though the beds are 16" deep with nice composted topsoil, I've noticed some of the more sensitive plants struggling. When I tried to put a shovel in the flower beds where he was running the machine, I struggled to dig a 1 gallon size shrub hole. I'm sure the compacted soil bordering the turf hasn't helped the drainage of the turf, either.

Anyway, that's my plight for the week, lol!

Any thoughts are welcome.