New Landscape Drainage Issue

Discussion in 'Landscape Maintenance' started by BFuller, Jan 29, 2012.

  1. BFuller

    BFuller LawnSite Member
    Posts: 44

    I'm dealing with a drainage problem and would appreciate some feedback.

    In a new residential landscape we installed in the fall of 2011 a drainage problem had reared its ugly head.

    The main yard 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 and here's why... 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.

    I've checked back on some pics I took of the finished subgrade and all my drainage patterns look good.

    I can upload a couple of pics if that would help. Anyway, that's my plight for the week. Any thoughts?
  2. agrostis

    agrostis LawnSite Silver Member
    Posts: 2,297

    You need to post picture's.
  3. Dr.NewEarth

    Dr.NewEarth LawnSite Bronze Member
    Posts: 1,441

    Barry, it sounds like you need a sump and a French Drain unless you can somehow daylight a drain through the retaining wall. What a PITA.
  4. BFuller

    BFuller LawnSite Member
    Posts: 44

    Here's 2 pics...

    You can see that the subgrade preparation pic shows positive drainage toward the irrigation boxes. The other pic shows the retention of excessive moisture where the bedding meets the turf.

    Walking off the sidewalk, on the turf, is fine, but the further you get towards the bedding, the wetter it gets. The thing that's throwing me off is the bubbling and air pockets under the sod that I mentioned in my original post. I was suspicious of a problem within a few weeks of installing the turf because the turf never did reach a nice deep green color, even after fertilizing.

    I'm thinking a drain line (french drain) coupled with sightly raising the grade with sand and new sod over the effected areas should fix the problem. I'd rather overkill this situation and be done with it as that's usually my approach. The good news is this customer is very happy with our services and has confidence in us. He wants on-going maintenance, lighting, water feature, etc. In fact, i'd like to clone him! The reason for posting here is to get a meeting of the minds and make sure I'm not overlooking anything.

    Any thoughts? Also notice the plants that are stressed from water, too, like the 3 or 4 Taxus. Btw... the beds have been weeded since these pics.

    Now, I'm heading over to the equipment forum and look for a cloning machine...


  5. agrostis

    agrostis LawnSite Silver Member
    Posts: 2,297

    That look's like a sump unless you can get out of that yard. I don't like sump's in this area because the clay is too deep.They just turn into big wet spot's. But it can be done if your soil is right. Do you know what the soil does 10 feet down ?

    Don't let those turf bubble's bother you. That's natural. I have seen what look's like a water bed under the turf because of the rain. The water move's between the (around here) clay below and about the top 2 inch's of grass. I have also seen little bubble's caused by rain forcing air out of the turf.
  6. BFuller

    BFuller LawnSite Member
    Posts: 44

    That basalt stone you see in the middle of the pic is marking a small rock pit I dug about 2 months ago, just to see what would happen. I thought about digging it out really big and doing a sump there.

    Right across the concrete walk to the left there is another bed with a huge downspout sump system for the house with a pump system in it. I wonder if I can get under that walkway with a connecting 4" PVC pipe.

    Anyone ever undertake getting under a walkway? It's about 4 ft. wide. I've seen irrigation companies do it.

    I'm still thinking on raising the finished grade with sand and new turf along the bed lines.

    No luck on the cloning machine yet.
  7. agrostis

    agrostis LawnSite Silver Member
    Posts: 2,297

    Going under a walkway is easy. Just don't leave a void that will cause it to break.
  8. BFuller

    BFuller LawnSite Member
    Posts: 44

    Actually, I messed up... The sump is located on the other side of the walkway to the right in terms of this pics orientation. You probably figured that out already, though, lol!

    What do you think about also raising the grade of the wet areas with sand and new turf. The irrigation system will protect turf in times of summer drought, and, here on the West coast of Canada, we get PLENTY of rain in the fall/winter months. Ot at least a soil mix with about 75-80% sand?
  9. agrostis

    agrostis LawnSite Silver Member
    Posts: 2,297

    I knew something wasn't right with that picture. I don't think raising the grade will work. That soil will just act like a sponge and won't dry out. You need to fix the drainage right the first time so you don't have to mess with it again.
  10. BFuller

    BFuller LawnSite Member
    Posts: 44

    I'm still wondering what the actual cause of the drainage problem is. It must have to do with the fact that the builder didn't install drainage behind the poured concrete wall and the subgrade isn't draining as it should. My drainage patterns seemed good before I installed the soil. On a rainy day before we installed the soil the water didn't sit in those areas.

    The soil installed was a composted bedding mix for the planting areas and a 65-70% sand mix under the turf.

    I'm hoping this drainage line we want ti install is the answer. I only want to to this once!

Share This Page