Evaluating the potential stormwater retention of a living retaining wall system

Abstract

Redesigning standard revetment or retaining walls to capture stormwater could increase the use of living walls and, thus, expand their beneficial impacts, including greening underutilized space. This study evaluated the potential stormwater retention and percent plant coverage of an experimental wall surface for six treatments (five vegetated Sedum treatments and an unplanted ‘control’ wall) on 18 circular living retaining wall systems designed from a standard retaining wall system. Percent stormwater retention, which compared effective precipitation volumes with stormwater runoff volumes, was quantified for 81 storm events from July 2010 to September 2011. Living retaining wall systems planted with S. (Phedimus) takesimensis retained stormwater more effectively than the unplanted wall and other planted treatments, including walls planted with S. spurium, mixed Sedum species, and S. kamtschaticum. Plant surface coverage of the living retaining wall system was the greatest when planted with mixed Sedum species, S. spurium, and S. kamtschaticum. Overall this study demonstrates that properly designed living retaining wall systems may be able to be used as a best management practice for stormwater retention in urban areas. Further study could determine the performance of living retaining walls with a more conventional design (i.e., single aspect vs. four aspects against a slope), over a longer time period, walls planted with other vegetated treatments, and walls featuring different fill and plant materials.

Nature-based solutions for urban stormwater management: an overview

“…In this regard, in 2011, Ostendorf et al [67] analyzed the potential benefits of a green wall by determining the retention capacity of the planted wall.…”

Concrete for Living Walls: Current Status and a New Design Recommendation

“…Vertical greening systems may effectively compensate for the lack of green spaces in densely populated urban areas. Vegetated walls may not only contribute to the physical and mental health of residents, but can also mitigate the effect of heat islands [1], reduce energy consumption for heating and cooling [2], sequester carbon dioxide [3], act as an air filter capturing small particulate matter [4], and contribute to storm water management by reducing the runoff of rainwater into the streets [5]. "Vertical greening system" is a general term for both green façades and living walls [6].…”