Gardens Go Vertical

Dec. 4, 2008

About the author: Niklas Jansson, P.E., is vice president of Soil Retention Systems Inc. Jansson can be reached at 760.966.6090 or by e-mail at [email protected].


As sustainability grows increasingly popular, it is incumbent upon building and landscaping material suppliers to provide products that promote the conservation of natural resources. Also referred to as “green” development, sustainability promotes the creation of environmentally sound and resource-efficient buildings and communities by using an integrated approach to design that is sensitive to natural resources and their preservation.

Solid concrete and asphalt, both of which promote runoff and pollution by contaminating streams, rivers and oceans, are still the primary materials used for roadways, walls and other hardscapes. There are new concepts and products available today, however, that could greatly reduce runoff and help protect the environment. While they require some new thinking and approaches, the techniques and materials will grow increasingly prevalent because they represent the future.

Soft Engineering

One concept that is gaining popularity is “soft engineering,” a practice evolving among land planners and civil engineers that is designed to integrate the built environment into the natural ecology of land and watersheds by using conservation-based techniques. The goal is “to create an interface that is economical and practical yet attractive and sustainable,” according to Patrick Fuscoe, founder and chief executive officer of Irvine, Calif.-based Fuscoe Engineering, a pioneer of soft engineering strategies and tactics.

In laymen’s terms, soft engineering boils down to being more environmentally sensitive in civil engineering designs, according to Fuscoe. This approach includes the use of more permeable components in building structures such as walls and roadways. Permeability promotes water absorption, thus reducing runoff and water contamination, and creates a more pleasant, natural environment. Additionally, soft engineering encompasses and promotes environmentally sensitive grading and surface improvements, hydrology, sustainable landscaping, wetland engineering, biofiltration and green building.

As sustainability, including soft engineering, becomes more popular and necessary, manufacturers who supply the building and land development industries will need to be more creative in designing and manufacturing products that will promote—or at least not hinder—conservation. It is also important that these products sustain their looks and durability over time.

Plantable Retaining Walls

A major component of building that has evolved over the years into a more environmentally sensitive product that complements sustainable development is retaining walls.

One of the biggest improvements in retaining wall systems is the plantable wall, which provides the strength of a standard retaining wall plus the ability to sustain live landscaping such as flowers and vines to greatly enhance its attractiveness. It is not uncommon for people to complain about the inclusion of retaining walls in a project because it is automatically assumed that the walls will be looming concrete structures and community eyesores. However, with plantable retaining walls, developers can frequently secure approvals for projects that incorporate the structures, and some municipalities allow for development variances based on the use of plantable walls.

Take, for instance, Crystal Cove, an Irvine Co. development in Newport Coast, Calif. It called for numerous retaining walls up to 40 ft high that initially raised eyebrows among local residents concerned about the effect of massive concrete walls on the look and feel of their coastal neighborhood’s multimillion-dollar homes. The Irvine Co. was able to convey its vision to the public through top consultants such as Forma Design Inc. and Hunsaker & Associates. After environmentally conscious planning, Crystal Cove is now one of the world's top developments and has won several awards.

Due to aesthetics, some communities have strict regulations on how high a retaining wall can be, but builders can go higher with a plantable wall than with other systems. In Fullerton, Calif., where California State University is building new homes for the school’s faculty and staff, there was initially resistance to the idea of the retaining walls needed to shore up hillsides. The neighborhood is on a hilltop, and the development required staggered retaining walls of up to 35 ft to support portions of the hill. Neighbors and city planners were concerned, but when the developer displayed images showing what plantable retaining walls would look like fully covered with mature landscaping, resistance subsided and the badly needed housing project was approved.

When retaining wall systems are used properly, they also open up land that might not otherwise be usable because they allow for the use of steeper slopes. For instance, at a Standard Pacific Homes development in the San Clemente, Calif., community of Talega, backyard space was at a minimum, and retaining walls provided homeowners with 10 ft of additional usable space.

Finally, and perhaps most importantly, plantable walls can lessen a development’s environmental impact by allowing plants to grow within their structure, promoting a natural, cleaner environment. This is especially true in canyon areas where there may be considerable habitat and plant life. Instead of filling in these canyons with big fill slopes, the walls provide a natural-looking interface between the built and existing environments.

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