Kurt Leuthold, PE, LEED AP, Vice President and Senior Civil Engineer, Barr Engineering Co.

Erin Anderson-Wenz

Track: How-to

Abstract

New research and technical analysis tools have led to an increasing awareness of the importance of trees and tree canopies in watershed management.  Some of the ecological and economic benefits that trees provide include reducing stormwater runoff, enhancing water quality, preventing soil erosion, providing wildlife habitat, improving air quality, conserving energy, increasing property values, and promoting green, livable communities.  To demonstrate how trees can be used to meet water quality goals within a watershed, a few case studies will be presented that provides a closer look at the technical aspects of trees in stormwater management systems, including BMP selection, important design criteria and long term maintenance issues.  In 2010, the Ramsey Washington Metro Watershed District (MN), in partnership with Maplewood Mall (a large regional shopping mall), started construction of a project to provide a significant amount of runoff treatment from a large area of the mall’s parking lot.  Recognizing the multiple benefits of trees and a tree canopy in an urban setting, “tree trenches” were designed as the primary a treatment system.  The latest research and design ideas from Stockholm, Sweden were incorporated into the design.  Stockholm is recognized as a leader when it comes to innovative methods for growing healthy urban trees.  In recent years, the city of Minneapolis has successfully implemented a variety of projects combining trees and stormwater management.  Lessons learned from some of these projects will also be discussed.  The long term goal of these projects is to determine the effectiveness of using trees in stormwater management.