California Department of Transportation

Preserve Existing Vegetation

Preserve Existing Vegetation

What is This Treatment?

Preserving existing vegetation involves strategically minimizing the disturbance to existing site vegetation required to construct a transportation project. Vegetation is typically preserved by including a specification that directs the Contractor to avoid disturbance of specific areas, and/or including a specification that directs the Contractor to install orange construction fencing to protect the vegetation. Preserving healthy existing site vegetation is more effective at maintaining stormwater quality than removing and planting new vegetation .

Where to Use This Treatment:

  • Use on all projects that include existing native or non-native vegetation.


  • Most effective method to maintain water quality, and minimize runoff volume and velocity.

  • Most cost effective method to maintain water quality.


  • Preservation of existing vegetation may not be possible due to the earthwork required to construct the project.


  • Standard Special Provision - Temporary Fence (Type ESA)
  • Standard Special Provision - Environmentally Sensitive Area

Plans and Details:

  • See Caltrans Standard Plan for Temporary Water pollution Control Details [Temporary Fence (Type ESA)].

Estimate Information:

  • Use BEES Code 141000 Temporary Fence Type ESA to specify fencing that protects existing site vegetation from disturbance.
  • Temporary Fence Type ESA prices vary but typically run about $5.00/lineal foot.
  • There is no contract cost (Bid Item) associated with the Environmentally Sensitive Area specification.


Updated: April 14, 2014