1717488Amend006dwg_CIVIL_030326.pdf

This document is a set of construction design and engineering drawings for stormwater management facilities at a federal site. The drawings depict detailed plans, sections, and specifications for constructing bioretention areas, sediment chambers, overflow basins, outlet structures, and associated erosion control measures across approximately 3,600 cubic feet per acre of treatment area.

The project requires contractors to install temporary and permanent erosion control measures, construct multiple storm structure catch basins with specific invert elevations and pipe connections, install outlet protection structures and bioretention facilities with filter fabric and stone media, and implement sediment fencing and slope protection during construction. Key construction specifications include: placement of 4-inch diameter underdrains with perforated piping; installation of reinforced concrete structures with specified concrete slab elevations and embedment depths; use of Class II plastic pipe for storm drainage; and installation of Class B riprap and filter fabric for stabilization. The drawings specify maintenance requirements including weekly inspections of sediment fencing, removal of accumulated sediment within specified depths, and stabilization of disturbed areas with permanent vegetation. All imported materials must be from permitted sites, and the contractor is responsible for temporary power, water supply, equipment parking, and controlled site access during construction. The project site is located in North Carolina and references compliance with North Carolina Department of Environmental Quality standards for erosion control practices and sediment management.