1996-02-06_REVISION - M1977493 (14)

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i Chapter 4-Site-Specific Industrial Storm Water BMps Preservation of. Natural Vegetation I What Is It The preservation of natural vegetation (existing trees, vines, brushes, and grasses) provides natural buffer zones. By preserving stabilized areas, it minimizes erosion potential, protects water quality, and provides aesthetic benefits. This practice is used as a permanent control measure. I When and Where to Use tt This technique is applicable to all types of sites. Areas where preserving vegetation can be particularly beneficial are floodplains, wetlands, stream banks, steep slopes, and other areas where erosion controls would be difficult to establish, install, or maintain. What to Consider Preservation of vegetation on a site should be planned before any site disturbance begins. Preservation requires good site management to minimize the impact of construction activities on existing vegetation. Clearly mark the trees to be preserved and protect them from ground disturbances around the base of the tree. Proper maintenance is important to ensure healthy vegetation that can control erosion. Different species, soil types, and climatic conditions will require different maintenance activities such as mowing, fertilizing, liming, irrigation, pruning, and weed and pest control. Some State/local regulations require natural vegetation to be preserved in sensitive areas; consult the appropriate State/local agencies for more information on their regulations. Maintenance should be performed regularly, especially. during construction. Advantages of Preservation of Natural Vegetation • Can handle higher quantities of storm water runoff than newly seeded areas • i • Does not require time to establish (i.e., effecti,,e immediately) • Increases the filtering capacity because the vegetation and root structure are usually denser in preserved natural vegetation than in newly seeded or base areas • Enhances aesthetics • Provides areas for infiltration, reducing the quantity and velocity of storm water runoff • Allows areas where wildlife can remain undisturbed • Provides noise buffers and screens for onsite operations • Usually requires less maintenance (e.g., irrigation, fertilizer) than planting new vegetation Disadvantages of Preservation of Natural Vegetation • Requires planning to preserve and maintain the existing vegetation • May not be cost effective with high land costs • May constrict area available for construction activities 4-53