ICF’s production system integrates biological, and mechanical practices that foster cycling of resources promotes ecological balance and conserves biodiversity.
The Use of Vegetative/Landscape Caps
A vegetative cap is a long-term, self-sustaining cover of plants growing in or over materials that pose an environmental risk; the vegetative cap reduces that risk to an acceptable level. Vegetative caps have a vegetative layer as the uppermost layer of the cap design (Optional Cover Layer mentioned in Section 3.2 under Definition). Vegetative caps are generally 2 feet thick but can vary based on site-specific conditions. Caps can incorporate multiple layers to prevent direct contact. A vegetative cap typically includes the following three layers:
a) Vegetated Topsoil b) Clean Soil Layer c) Separation/Demarcation Layer
The vegetated topsoil layer assists in the prevention of erosion of the soils of the cap from wind and rain. The vegetated topsoil layer is typically 6 inches thick but should be thick enough to support the vegetation. If deeper rooted vegetation (trees and shrubs) is planned, the topsoil thickness may increase, or even be built up above the surrounding grade. It should be spread evenly and not overly compacted.
The clean fill layer is usually 12 to 18 inches thick. If this layer will also serve for drainage, filter fabric is commonly installed to prevent the vegetated topsoil layer from clogging the drainage pores.
The separation/demarcation layer is a visible barrier (such as snow fence, geotextile, distinctly colored soil) that is intended to provide a clear separation between the cap and the underlying impacted material, prevent mixing, and possibly provide structural support. http://www.nj.gov/dep/srp/guidance/#presumptive_alt_remedy
Hügelkultur is a composting process employing raised beds constructed from decaying wood debris and other compostable biomass plant materials. The process helps to improve soil fertility, water retention, and soil warming, thus benefiting plants grown on or near such mounds. Hügelkultur replicates the natural process of decomposition that occurs on forest floors. Trees that fall in a forest often become nurse logs decaying and providing ecological facilitation to seedlings. As the wood decays, its porosity increases allowing it to store water “like a sponge.” The water is slowly released back into the environment, benefiting nearby plants. Mounded hügelkultur beds are ideal for areas where the underlying soil is of poor quality or compacted. They tend to be easier to maintain due to their relative height above the ground. The beds are usually about 3 feet (0.91 m) by 6 feet (1.8 m) in an area and about 3 feet (0.91 m) high.