City Trees is a premier publication focused on urban + community forestry. In each issue, you’ll learn how to best manage the trees in your community and more!
Issue link: https://read.dmtmag.com/i/30662
Because there is little precipitation in West Sacramento from June through October, trees and plant material within the planter are irrigated during these months. Any tree suitable for your region can be planted within these planters because they drain rapidly, even during a major storm event. However, it is not advisable to plant trees with aggressive root systems as they could impact the flow of water to the perforated pipe below. Decorative plant material surrounding the tree should also be chosen from plants suitable for the region. Please note that the root barriers in the drawings on page 30 were removed once the tree was planted to allow the tree to develop a healthy root system. —Dena Kirtley, Urban Forest Manager, City of West Sacramento, CA This entry highlights water quality projects designed by the Milwaukee, Wisconsin Environmental Engineering Section in 2008-2010. The projects demonstrate how City roads can be redesigned to become a solution to stormwater quality problem rather than a source for pollution. These bioswales are part of Milwaukee’s Green Built Environment Roadway Projects. The new bioswales function as filtration/infiltration devices. Runoff from the roadway enters the facilities through curb cuts and filtrates/infiltrates through two layers of engineered soil and crushed stone. The runoff receives its initial treatment through the salt tolerant plant combinations in the landscaped area before it infiltrates through the amended engineered soil. A portion of the treated runoff then makes its way to the sewer system through installed perforated pipes in the crushed stone layer, while the other portion evaporates and evapotranspirates through the planting system. In each project, the conventional landscaped medians were redesigned to capture, slow, treat, and infiltrate street runoff. In addition to providing direct environ- mental benefits, the project also provides a visual amenity for the neighborhood and is aesthetically integrated into the urban streetscape. The project con- sists of installing bioretention facilities to replace the conventional medians. The facilities are designed to provide a removal rate up to 90% of total suspended solids from roadways. Things to Consider Before Installing a Bioswale Three perspectives on a West Sacramento, California storm- water planter; see diagram for construction details • Photos by Dena Kirtley www.urban-forestry.com 1. Plant site-tolerant (drought, wet, salt), low maintenance, aesthetically pleasing vegeta- tion (including trees). 2. Topsoil must be a specially engineered mix from a reputable supplier. 33