Agenda - 06-21-2022; 8-l - Orange County Southern Campus Expansion Stormwater Operations and Maintenance Plan Agreement with Town of Chapel Hill (2501 Homestead Road, Chapel Hill)

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21 Table 1: Inspection and Maintenance Provisions for Wet Pond FREQUENCY OF MAINTENANCE ACTIVITIES INSPECTIONS IR Upon • Watering is needed twice a week until the plants on the vegetated shelf and completion of perimeter of the basin become established (commonly 6-8 weeks), depending construction on rainfall. • Mow grass surface areas to a height of approximately six to eight inches and remove grass clippings. • Check inlet system/forebay and outlet device for any obstructions or clogging. Once a quarter Remove accumulated grit, leaves, and debris and dispose off-site. • Remove any trash within the pond area. • Inspect for ponding and bare or eroding areas and make adjustments before the next rainfall as necessary. Twice during the growing • Pull out dead or diseased plants, weeds, or invasives preferably by hand. season • Have the embankment inspected by a dam safety expert. • Remove woody species on or near embankment area and maintenance access. Annually A dam safety specialist should be consulted to remove any trees. • Prune trees and shrubs to best professional practice. Thin vegetation so that sunlight can penetrate the pond surface. Vegetation • If the wet pond suffers from dead or diseased plants or overgrown with invasive species, evaluate the source of the problem: soils, hydrology, species, and/or type of disease to determine the cause of the plant failure. o Remediate the problem by selecting new species and/or implementing an eradication plan for invasives. o Ensure appropriate plant maintenance is occurring. o A one-time fertilizer application to establish ground cover is permissible As needed if a soil test indicates it is necessary. No portion of the wet pond system (Typical shall be fertilized after the initial fertilization that is required to establish Problems) the vegetation. o Consult with the Town of Chapel Hill Stormwater Management Division If algal growth covers 50%of the area, consult a professional to remove and control the algal growth. • If cattails, phragmites, or other invasive plants exceed 50%of the wet pond, remove invasives by physical removal or wiping them with a herbicide. Consult the Town of Chapel Hill before any aquatic herbicide is used. Site specific approval is required. Extended periods of dewatering may be a possible treatment approach for reducing invasives.