When a national banking giant decided to build a Corporate Leadership Center for management training in SeaTac, Washington, they sought the expertise of two firms ?EUR??,,????'??+ GGLO, who would later design the Center?EUR??,,????'???s 18-acres of learning, recreational, dining and guest housing facilities, and Hendrikus Schraven Landscape Construction & Design, who revolutionized the landscaping/ erosion contol industry with the advent of the breakthrough living Biostable?EUR??,,????<
Mission Implausible?
But first, a quick look at the project, pre-Hendrikus. GGLO?EUR??,,????'???s mission sounded simple enough: incorporate over 7 acres of wetlands?EUR??,,????'??+a primary site feature that served to inspire and inform the Center?EUR??,,????'???s design?EUR??,,????'??+into the overall scheme. Of course, what works on paper does not always translate well into real life, especially when plans call for the disturbance, preservation and restoration of the original environment. While GGLO sought to clear the site of invasive plants, they also needed to manipulate the mixed forested wetlands to fit the design scheme without disturbing the wetlands or the adjacent buffer of native species that would serve as a natural, aesthetic transition to the unatural lines of wood, plaster and concrete. Plus, GGLO had to contend with the type of unusually wet winter conditions that could render any construction on a wetlands-intensive site virtually impossible. Meanwhile, there was the matter of saturated clay soils and steep slopes with low-grade tolerance that threatened to extend into the wetland buffer?EUR??,,????'??+creating the potential for erosion. To make the land useable for parking and sidewalks, an imported structural fill would be needed to provide a compactable sub-base that could support such man-made structures.

The Soil Solution
Knowing that the demands of the project and the unpredictability of the site?EUR??,,????'???s landscape resulted in a situation too incongruous to handle themselves, the project?EUR??,,????'???s landscape architects consulted with the city of SeaTac, as well as with soil experts, to devise a solution that would facilitate, as well as expedite, building in such a sensitive environment. Enter Hendrikus Schraven Landscape and Design. With over 28 years of organic landscape construction, design, erosion control work and organic product development, plus erosion control innovations and soils, the soil pioneers were more than ready to take on the delicate task of stabilizing the unpredictable landscape in preparation for building.

Tools of the Grade
Hydroseeding

 
Hydroseeding alone does not necessarily reduce runoff and will only give long term erosion control if the soil sub base is fertile and extensive enough for good root penetration. In addition to hydroseeding wild native grasses, the project required many native plants and trees as well. GGLO wanted to design from a planting palette that blended with the existing wetlands area. A strong fertile soil base was needed to support these plants. EssentialSoil?EUR??,,????<


Cellular Grids, Retaining Walls, Rockeries and Stone Embankments
GGLO did not want to use cellular grids, retaining walls and rockeries because they wanted the natural character of the wetlands to be preserved and extended onto the slope area. Stone embankments, layers, and/or buttresses were also not used because these options did not support rich plant growth or the aesthetic purposes of the project. The spreading of various sizes of stone rubble was also not an option because of the appearance of such a method.

Installation of EssentialSoil
A method was used that is as simple as it is effective. In fact, the method of Bio-Stable?EUR??,,????<
Managing Irrigation Scheduling
One challenge was to manage the scheduling of the irrigation. The irrigation system was designed before the decision to use EssentialSoil?EUR??,,????<
Treatment of Sub Soil
Because most of the sub base under the EssentialSoil?EUR??,,????<
Living Microbial Innoculation
Following the installation of EssentialSoil?EUR??,,????<


Long Term Benefits
These include decreased irrigation costs in the area of EssentialSoil?EUR??,,????<