Live Pole Drain Systems

WALKER ’S LANDING LIVE POLE DRAIN SYSTEM

Location: Walker’s Landing Road, Riondel, British Columbia.

Client: Ministry of Transportation and Highways British Columbia.

Objective: To stabilize a slope failure by providing drainage of surface and sub-surface seepage water using a live pole drain system in combination with other soil bioengineering techniques.

A series of two slope failures occurred at the Walker ’s Landing site, in February and December of 2002. In March of 2003 the site was re-contoured and planted with brush layers, using a Spyder Hoe and manual labour.

Link to: Main Walker's Landing page

In addition to the brush layer structures, a “live pole drain system” in conjunction with lateral drain fascines was installed to drain seepage water emerging at the upper portion of the slope. The installed system was designed to follow the lay of the land and branched out mid-way down the slope, directing water to each side of the failure at the toe.

The live pole drain system used consisted of cylindrical bundles of live cuttings of approximately 25 cm in diameter and 4 m in length secured to the slope using steel re-bar. The species used were a mix of Willow (Salix bebbiana/scouleriana/exigua), Black Cottonwood (Populus balsamifera ssp. trichocarpa), and Red-Osier Dogwood (Cornus stolonifera).

The site was monitored in 2003, 2004 and 2005. The results found the system working efficiently at draining seepage water and stabilizing the slope. The survival of the vegetative structures was also found to be very good.