- 2010 Standards
- Aesthetic Barriers
- Blue Star Memorial Highways
- Classified Landscaped Freeways
- Community ID
- Context Sensitive Solutions
- Erosion Control Toolbox
- Gateway Monuments
- Main Streets
- Mission Bells
- New Product Review
- PS&E Guide
- Roadside Toolbox
- Safety Roadside Rest Area System
- Scenic Highways
- Transportation Art
- Visual Impact Assessment Outlines
- VIA Training
- Water Conservation
Erosion Control Toolbox
Planning & Design
Improve Soil Health
- Soil Rehabilitation
- Local Topsoil
- Imported Topsoil
- Roughen Soil Surface
- Stepped Slopes
- Contour Grading and Slope Rounding
- Decompact Soil
- Incorporate Materials
Improve Soil Health & Provide Cover
Short Term Cover
Long Term Cover
Steep Slope Techniques
- Stepped Slope
- Cellular Confinement
- RECP Flap
- RECP Flap with Brush Layering
- RECP Wrap
- Soil Filled RSP
- Wire Blanket
- Wire Mesh Confinement
- Plant Selection
- TransPlant Application
- Noxious and Invasive Species
- Drill Seed
- Dry Seed
- Native Grass Sod
- Brush Layering
Low Impact Development
- Sidewalk Stormwater Planter
- Sidewalk Stormwater Tree Trench
- Parking Stormwater Planters
- Permeable Paving
- Additional Resources
- RUSLE2 Quick Start
What is This Treatment?
Local topsoil is topsoil obtained from within the project limits and includes removing, stockpiling, and placing local topsoil on areas disturbed by construction activities.
Local topsoil is the one of the most effective methods to establish vigorous vegetative coverage because local topsoil typically contains the ideal physical, chemical and biological properties to establish vegetation.
Where to Use This Treatment:
- Typically applied on slopes 1.5:1 (H:V) and flatter. The following application rates are suggested:
- Slopes 1.5:1 (H:V) - 2" maximum thickness.
- Slopes 2:1 (H:V) - 3" maximum thickness.
- Slopes 3:1 (H:V) - 4" maximum thickness.
- Slopes ≤ 4:1 (H:V) - 6" maximum thickness.
- Caltrans Highway Design Manual Topics 110.2(2) and 110.2(4) recommend considering the use of Local Topsoil to treat disturbed soil areas to help protect stormwater runoff quality.
- Reduced stormwater runoff volume and velocity.
Improved infiltration rate.
Improved soil water holding capacity.
Improved soil structural properties - soil structure, porosity, and texture.
Improved soil chemical properties - providing proper pH, carbon, nitrogen, potassium and phosphorus levels.
Improved soil biology - activity by bacteria, mycorrhizal fungi, nematodes, protozoa, microarthropod and earthworms.
Improved soil nutrient levels and nutrient cycling.
Improved potential for vigorous long term vegetation coverage.
More costly (yet more effective) than surficial treatments such as Erosion Control (Hydroseed).
Requires temporary storage space within the project limits to stockpile materials.
Requires removal of noxious weed species prior to harvesting of materials from the project site.
Requires site accessibility by earthwork equipment.
In the 2010 specifications, specify Local Topsoil as follows. (1) Local Topsoil is defined in the 2010 Specifications in Section 21-1.02D Topsoil. This definition of Local Topsoil references Section 19-2.03D Selected Material, which provides additional information on how to handle Local Topsoil. (2) Because Local Topsoil is specified as Selected Material, Local Topsoil is paid for as Roadway Excavation. (3) Show the areas to be excavated and areas to be applied on the plans. (4) Include the bid item for Roadway Excavation in the Bid Item List.
Consider Using This Specification With:
To provide protection for the soil surface, consider combining this treatment with:
- Duff - a duff layer reduces raindrop impact erosion and serves as a source of native seed and mycorrhizal fungi.
- Compost with seed applied at the same time.
Plans and Details:
- There is no Standard Plan for Topsoil
- No BEES Code, Local Topsoil is paid for as Selected Material.
- Caltrans Highway Design Manual Topic 110.2(2) and Topic 110.2(4)
- California Department of Transportation, "Performance of Erosion Control Treatments on Reapplied Topsoil", May 2005.
- Caltrans Erosion Control New Technology Report, Topsoiling With Cellular Confinement, June 2003
- Caltrans Stormwater Quality Handbook - Project Planning and Design Guide, See Appendix A, Section A.5 Slope/Surface Protection Systems.
- 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
- Michael Hogan, 2009. "Sediment Source Control Handbook, An Adaptive Approach to Restoration of Disturbed Areas" Accessed 2009-07-16.