California Department of Transportation


Mulch Photos

What is This Treatment?

Mulch work involves placing a blanket of organic material on fill slopes, cut slopes, and other disturbed roadside areas to reduce erosion and reduce weed competition. Mulch is typically applied from 2" - 3" deep.

The mulch specification allows the designer to select from the following materials:

  • Composted green material.
  • Tree bark.
  • Wood chips.
  • Coarse woody grindings.
  • Pine needles.
  • Shredded bark.
  • Wood chips, tree bark, or a combination of both.

When to Use This Treatment:

  • Typically applied on slopes 2:1 (H:V) and flatter.
  • Use to reduce raindrop splash erosion and competition from weeds.
  • Typically applied 2"-3” deep (270-400 cubic yards/acre).


  • Improved protection from raindrop splash erosion.

  • Reduced competition from weed species.

  • Reduced stormwater runoff volume and velocity.

  • Improved infiltration rate.

  • Conserves soil moisture.
  • Improved potential for vigorous long term vegetation coverage.

  • Easy application by pneumatic blower trucks or bulldozers (in flat areas).


  • Requires temporary storage space within the project limits to stockpile materials.
  • Applying high levels of organic materials may not be appropriate in arid regions of the state.

  • Functional longevity of less than three years.

Mulch Quantity Calculator

Depth Enter design depth.
Area (SF) Enter area in square feet. For example 1 acre = 43560 square feet.
Cubic Yards  
Cubic Feet  


Consider Using With:

To effectively treat sites with poor soils (compacted, nutrient depleted, or poorly draining), consider combining this treatment with:

Plans and Details:

Specify Mulch in the Erosion Control Legend:

Jute Mesh


Estimate Information:

External Links:

  • David Steinfield, Scott Riley, Kim Wilkinson, Thomas D. Landis, Lee Riley, et al. 2007. "Roadside Revegetation, An Integrated Approach to Establishing Native Plants" Accessed 2009-07-16

Updated 04-15-2014