Caltrans Compost Specifications
According to California Integrated Waste Management Board (CIWMB), over 12,000,000 tons of compostable materials were landfilled in California in 2003. Not only does this practice consume valuable landfill space, this disposal of compostable organics misses out on the contribution compost brings to improving soil structure and fertility, improving infiltration, reducing runoff, promoting healthy vegetation, reducing erosion, and improving water quality.
In 2005, the California Integrated Waste Management Board (CIWMB) partnered with Caltrans, the University of California Riverside (UCR) Extension, the Association of Compost Producers (ACP), the United States Compost Council (USCC), UC Cooperative Extension, Filtrexx, and Soil Control Laboratories to identify and address the barriers preventing Caltrans from maximizing its use of compost. Working together, these various stakeholders developed a suite of compost specifications that resolved historic barriers to compost use including cost, availability and quality control. A series of six workshops were held statewide in 2006 to introduce these specifications to Caltrans designers and contractors, compost producers and other interested parties in city, county, or regional governmental agencies that might be interested.
2007 Compost Workshops
Caltrans and the California Integrated Waste Management Board (CIWMB) completed a series of workshops on managing storm water, controlling erosion, and improving roadside vegetation through compost-based BMPs. A series of workshops were held on the dates noted below. Click the appropriate link below for the draft workshop agenda.
- San Luis Obispo - August 21, 2007
- Chino - August 23, 2007
- Redding - September 25, 2007
- Lake Tahoe - September 27, 2007
For more information on these workshops, please visit the following web page hosted by the Integrated Waste Management Board:
http://www.ciwmb.ca.gov/organics/Erosion/Workshops/2007BMPCT/Default.htm
2006 Compost Workshops
In 2006, Caltrans and the California Integrated Waste Management Board (CIWMB) held 5 workshops across the state that focused on managing storm water, controlling erosion, and improving roadside vegetation through compost-based BMPs. Click the link below to view the 2006 compost workshop presentations.
http://www.ciwmb.ca.gov/organics/Erosion/Workshops/2006BMPCT/Agenda.htm
2006 Compost Workshop Presentation
Compost Calculator
Compost Application Rates
| Compost Depth | Cubic Yards/Acre | Pounds/Acre | Tons/Acre |
|---|---|---|---|
| 1/64" | 2 | 1,725 | 0.9 |
| 1/32" | 4.3 | 3,450 | 1.75 |
| 1/2" | 68.5 | 54,800 | 27 |
| 1" | 135 | 108,000 | 54 |
1/64" compost is the maximim application rate for single step application of compost via a hydroseed rig.
Average Compost Weight = 800 lbs/cubic yard (1050 lbs/cubic meter).
A 40 cubic yard blower truck holds roughly 35 cubic yards of compost, and applies this compost at an approximate rate of 35 cubic yards/hour. A single truck should be able to apply a 1" thick compost blanket over a 2-acre site (280 CY total) in a single 8-hour working day. The average truck has a hose that can reach 300 feet - this is the typical limit of reach from the roadway. A rough estimate of cost for labor and materials for this work would run from $5,000 - $8,000 per acre. This price estimate does not include seed.
United States Composting Council (USCC) Seal of Testing Assurance (STA) Program
US Composting Council (USCC) Seal of Testing Assurance (STA) Program Participants
Caltrans compost suppliers must be participants in the United States Composting Council's (USCC) Seal of Testing Assurance (STA) program. The website linked above provides a current list of STA program participants.
For information on how to become a STA program participant, please visit the US Composting Council Seal of Testing Assurance webpage.
Publications
Compost Use for Landscape and Environmental Enhancement Manual
The California Integrated Waste Management Board's Compost Use for Landscape and Environmental Enhancement publication provides objective information regarding compost use in landscape plantings and environmental applications.
California Agencies Partner to Increase Compost Use On Roadsides
BioCycle Magazine, March 2007
Compost Use for Erosion Control
Performance in Construction and Roadway Projects
Erosion Control Magazine, May 2006
Studies in Compost
A Closer Look at an an Economical Erosion Control Alternatve
Erosion Control Magazine, April 2005
Infiltration Through Disturbed Urban Soils and Compost-Amended Soil Effects on Runoff Quality and Quantity
Urban Watershed Management Branch, Water Supply and Water Resources Division, U.S. Environmental Protection Agency
The report examines common problems associated with the impact of land development on soils. Land development dramatically alters the natural soil structure, reduces infiltration and groundwater recharge. These changes have dramatic effects on watershed uses. This project measured these changes, identified significant factors reducing infiltration, and evaluated a potential management strategy to reduce these detrimental effects.
Compost and Tillage for Plant Establishment
Researching Roadside Plots in San Jose
Erosion Control Magazine, April 2007
Snowblowers in Summer?
Caltrans Applies Compost Blankets for Roadside Erosion Control
Caltrans News, February 2006
Caltrans BMP Retrofit Pilot Program
Compost Related Erosion Control Specifications
The Standard Special Provisions (SSPs) below are to be used together with Caltrans Standard Specifications. If the product or material that you are interested in is not included in the SSPs below, please look up that product (for example, straw, fiber, stabilizing emulsion) in the Caltrans Standard Specification Manual.
Erosion Control (Type C)
Erosion Control (Type C) work includes applying seed, fiber, stabilizing emulsion (glue), straw, and compost to "fill" slopes. The seed, fiber and stabilizing emulsion are typically mixed in a slurry with water and applied from a hose attached to a hydroseed truck. Compost can either be applied together with the other materials in the slurry, or it can be dry-applied as a separate step in the process. While a separate dry application of compost has a higher labor cost, the material cost of the dry (bulk) compost can be up to 1/10th the cost of the bagged compost required for hydroseed application.
The Erosion Control (Type C) Standard Special Provision (SSP) is available on the Caltrans Standard Specification server.
Erosion Control (Type D)
Erosion Control (Type D) work includes applying seed, fiber, stabilizing emulsion (glue), and compost to "cut" or "fill" slopes. The seed, fiber and stabilizing emulsion are typically mixed in a slurry with water and applied from a hose attached to a hydroseed truck. Compost can either be applied together with the other materials in the slurry, or it can be dry-applied as a separate step in the process. While a separate dry application of compost has a higher labor cost, the material cost of the dry (bulk) compost can be up to 1/10th the cost of the bagged compost required for hydroseed application.
The Erosion Control (Type D) Standard Special Provision (SSP) is available on the Caltrans Standard Specification server.
Erosion Control (Drill Seed)
Erosion Control (Drill Seed) work includes placing seed in the soil with a drill seeding device similar to that used by farmers to plant agricultural crops. Placing the seed in the soil offers greater protection from the sun, wind, birds and like items that inhibit seed germination. To help improve soil fertility, and reduce erosion by high winds and rainfall, this specification asks that thin layer of compost and stabilizing emulsion (glue) be applied to the soil surface after the drill seeding work is complete.
The Erosion Control (Drill Seed) Standard Special Provision (SSP) is available on the Caltrans Standard Specification server.
Erosion Control (Compost Blanket)
Erosion Control (Compost Blanket work involves placing a thin layer of coarse compost to an area, and then applying the seed via hydroseeding or dry/hand application. If applied via hydroseed, fiber and stabilizing emulsion (glue) are to be applied as well. The compost protects the seed from the elements - promoting germination, provides nutrients to enrich the soil, and acts as a mulch - reducing competition from annual weed species, reducing storm water runoff, and helping conserve soil moisture.
The Erosion Control (Compost Blanket) Standard Special Provision (SSP) is now available on the Caltrans Standard Specification server.
Compost (Incorporate)
Compost (Incorporate) work involves incorporating 3-4 inches of coarse compost to a depth of 12-18 inches (roughly 30% by volume) in disturbed areas that are intended to receive planting to control erosion. The organic materials provided by the compost help improve soil structure and fertility, leading to improved infiltration, increased water holding capacity, reduced storm water runoff. This specification is in final Draft form, and will be placed on the Caltrans Standard Specification Server when internal review and comment are complete.
The Compost (Incorporate) specification is now available.
SOIL AMENDMENT
The revised Soil Amendment SSP requires soil amendment used on Caltrans projects to be compost produced from the following feed stocks: green material, biosolids, manure or mixed food waste and meet the environmental health standards of Title 14, California Code of Regulations, Division 7, Chapter 3.1, Article 7.
The revised Soil Amendment Specification is available on the Caltrans Standard Specification server as part of the May 2006 Amendments to the Standard Specifications. Scroll to Section 20-2.03 SOIL AMENDMENT to see the new language. If you have any questions regarding this specification, please call Greg Balzer at (916) 653-4337
MULCH
The revised Mulch spec still allows the designer to select and specify mulch from a list of materials including green material, tree bark, wood chips, and shredded bark - however the revised spec requires green material mulch be produced by a compost producer that belongs to the US Composting Council (USCC) Seal of Testing Authority (STA) program, as well as compost materials in conformance with with Title 14, California Code of Regulations, Division 7, Chapter 3.1, Article 7. Composting green material used as mulch will help ensure that mulch is free of harmful pollutants, pathogens and weed seed.
The Mulch Specification is available at this web site. If you have any questions regarding this specification, please call Greg Balzer at (916) 653-4337.