CALTRANS NEWS

Snowblowers in Summer?

Caltrans Applies Compost Blankets for Roadside Erosion Control

By Doug Brown
Caltrans Landscape Architecture Program

No, that's not really dirty snow, it's compost.

Caltrans is pioneering a unique and unexpected application for its snow-blowing equipment – using it to distribute compost to roadside areas.

In a demonstration last November in a Marysville maintenance yard, District 3 employees tested whether the specialized winter equipment could apply compost as an erosion control technique along highways.

Why? The innovative application of compost is an economical way of using materials that might otherwise be wasted. Caltrans is potentially the nation’s largest consumer of compost. The hypothesis proved to be correct. Snow-blowing equipment is a cost-effective way to apply large volumes of compost to areas along highways.

Typical compost pneumatic blower applies 300 cubic yards per day. A snowblower can put down 8,000 cubic yards per day.

Caltrans specifications call for compost as an erosion control blanket for revegetation and erosion control. A layer can effectively stabilize slopes and increase rainwater infiltration. Blanketing large areas requires hundreds, even thousands of cubic yards of compost. Current methods of application -- including pneumatic blowers, hydraulic applicators, bulldozers and hand shovels -- are slow, labor intensive and expensive.

Typical compost pneumatic blower applies 300 cubic yards per day. A snowblower can put down 8,000 cubic yards per day.

However, applying a two-inch layer of compost with large snowblowing equipment costs between $5,000 and $6,000 per acre – a significant reduction. Caltrans gains additional efficiency by using equipment that normally would sit idle during the off-season. And the snowblowers do the job three to four times faster than conventional equipment.

Snowblower scoops up windrow of mulch and blows it on roadside.

The procedure uses semi-trucks to “belly-dump” the compost in a long berm (or windrow), a motor grader for shoulder clean up and windrow construction, and a water truck for dust control. The demonstration showed that a snowblower can effectively apply compost up to 60 feet from the road by adjusting its throw angle and pitch. More conventional equipment can be used to apply compost in areas farther than 20 yards.

Acknowledgements: Thanks to D-3 Maintenance and Hilary Gans, BFI/Allied Waste Bay Area, for their contributions to this article.

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