Fixing Migrating Mulch Erosion Fixing Migrating Mulch Erosion

If you’ve ever had an area of your yard where you were constantly raking back and replacing mulch, you know how frustrating migrating mulch can be. However, migrating mulch can be a sign of a much more serious and costly issue: foundation erosion. The issue is usually caused by poor drainage around the outside of your house, specifically from a downspout.

Before installing anything in your yard, it is important to check your local building codes to ensure that your project isn’t in violation of any regulations. Also, have all utilities clearly marked to avoid accidentally cutting underground lines.

The first step to draining a downspout is locating an acceptable area where the water can be redirected. Find a low-lying ditch or gravel pit at least 20 feet from the house’s foundation. Alternately, you can divert the water to the street curb, which is designed for drainage flow (just check with the city first, as sidewalk issues can occur).

Make sure the place where the water will come out is lower in elevation than the downspout and that the ground is sloped away from the downspout, so the water flow is guided by gravity. Then:

  1. Dig a trench between the downspout and water receptacle, making sure there is a constant downward slope.
    Dig a trench between downspout and receptacle
  2. Install a solid drainage pipe from the adaptor to the ditch.
    Large downspout adaptor installed into flex drainIMG_0076
  3. Cover the pipe with 4″ of coarse gravel and/or topsoil to protect and hide the pipe.
    French Drain picture (2)
  4. Tie multiple lines together as needed with T/Y fittings and couplers.
    T/Y fittings and Couplers

Result: Water is diverted from the downspout, which stops mulch from washing away and protects your foundation.

While properly directed water flow from downspouts is essential to protecting your foundation and can help preserve mulch beds, the issue may persist even with proper drainage because of heavy rain, wind or foot traffic. Here are some things you can do to avoid stubbornly moving mulch:

  • Use hardwood bark mulch; it might still wash away, but is heavier than pinewood mulch and won’t float
  • Replace landscape fabric beneath mulch with newspaper
  • Put some edging around mulch beds (four inches should do it)
  • Use pine straw!

Share this Article