How to Botch Drainage in 365 days

Discussion in 'Landscape Architecture and Design' started by mdvaden, Oct 10, 2011.

  1. mdvaden

    mdvaden LawnSite Bronze Member
    Messages: 1,946

    Just had a chance to revamp a drainage problem this month. This one was unique, in that the prior "French drain" was installed about 1 year earlier.

    Important things to keep in mind:

    1. Never cover a French drain with sod or clay-like soil. That caps-off the drain line right away.

    2. Routing perforated drain pipe or pipe with holes in front of trees, without using a barrier, invites roots to clog the system prematurely.

    3. If the greatest source of excess water is the concrete patio, don't skip a drain line next to it.

    We get about 37 inches of rain per year. So if the lawn was already getting 37 inches or rain, a patio means 74 inches of rain that the lawn has to (or can't) deal with. To omit that one drain line, means half a swimming pool's worth of rain allowed to cause problems.

    The photo attached shows how the tree roots, in roughly a year, passed from the soil, through fabric in the trench, through the rock, through the pipe wall, and across the air space in the pipe: branching into a small wad of roots that would have continued to expand.

    This scenerio is related to why 90% of the time, I do not do free drainage estimates, but schedule paid one-hour consultations to take a close look at the property and whether next door properties are part of the equation.

  2. Dr.NewEarth

    Dr.NewEarth LawnSite Bronze Member
    Messages: 1,476

    Awesome information
  3. mdvaden

    mdvaden LawnSite Bronze Member
    Messages: 1,946

    On this particular project, the soil beneath was very impermeable. Even naturally, not just from construction compaction 25 years ago. So I made a special soil mix that was not as sandy as a golf green mix, and made the lawn convex, rather than flat.

    With small lawns, sometimes concave centers work with a catch basin. But I went convex this time so heavy rain water will head to the French drains along the sides.
  4. White Gardens

    White Gardens LawnSite Fanatic
    Messages: 6,776

    As for tree roots, their tough to stop regardless.

    You can use a silt sock on the pip and it helps, but eventually they will win.

    On some lawns I've worked on, I've found not only large 3" runners 20 feet past the drip-line, but also a few fibrous root masses out that far also.

    Only fix to me is to use heavy PVC with the drainage holes, silt sock, and a good clean-out setup to run an auger through someday.

  5. sservices

    sservices LawnSite Member
    Messages: 9

    This is what one tree root does in 10 years time in perf. pipe

  6. sservices

    sservices LawnSite Member
    Messages: 9

    The root is entering from the uncut section of pipe. This is from the same line of pipe.


  7. mdvaden

    mdvaden LawnSite Bronze Member
    Messages: 1,946

    Wow ... doesn't that look disgusting !!

    Wish I had some pics from the country club I worked at in the 1980s, that had poplar trees.

  8. JimLewis

    JimLewis LawnSite Fanatic
    Messages: 6,876

    Hey Mario! Long time no hear.

    I have trouble believing that root went through a good strong landscape fabric, then through the sock around the pipe, then through the small hole in the pipe into the drain. I mean, I'm seeing it. But I can hardly believe that. I've never experienced that in the drains we've built.

    Where are you getting your landscape fabric? I don't think roots would go through the stuff we use.
  9. mdvaden

    mdvaden LawnSite Bronze Member
    Messages: 1,946

    Don't know where the stuff came from that I replaced, but it was some pretty thick stuff. Whatever was over the pipe was thinner. It was not a full blown root invasion yet after the one-year period, but an intermittent penetration where roots got into the pipe every two to three feet. Odds are, in a second year, it would have slightly penetrated like every 6 inches of length with some tiny roots. I doubt it would have done heavy clogging until 5 years passed.

    But the root shown in the piece of pipe I posted, made a full penetration of every layer in about 1 year. I think the interesting part is how it sort of extended through the air a little bit. The trees were pines, so probably less invasive than aspen, maple, etc..

    For my own past installations, or consultations, I've promoted going past close proximity to trees with solid pipe or solid barriers other than fabric. Especially since almost every fabric I know of gets penetrated. Even the thick root ball bags I saw used in Medford nurseries.

    Having this rare opportunity to pull a 1 year old drain pipe out of the ground was a golden opportunity to document the value of the 1 hour consultations I've been doing throughout the past few years.

    : - )

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