Managing Soil Resources for Urban Restoration and Greening Projects.

Highly urbanized areas present many unique soil resource management challenges, especially related to the creation of parks or green spaces in sites that have been degraded by previous construction activities or constructed sites that are being returned to a more natural condition.  Existing site soils are always preferred for restoration of drastically disturbed or otherwise imbalanced sites where soil function and vegetation requires amendment.  However, the soils present at many urban restoration sites are unsuitable for use without significant modification due to high levels of contaminants or degraded physical properties.  In such cases it is necessary to replace the soil with a manufactured soil blend or to modify the existing soil with appropriate ingredients that will create the desired physical and chemical properties.  When soils must be imported to restore a site to ecological function and/or landscaping needs, procurement and placement of soils become a more critical issue than generally recognized by most people.  Specifications for replacement soils are typically provided by landscape architectures and are mostly driven by a desired set of physical properties rather than a holistic view of establishing or restoring soil ecosystem functions. This presentation will highlight recent examples where successful site restoration was achieved, including landscapes for urban stormwater management.  Additionally, some of the organic and inorganic materials used in site restoration will be examined and discussed.