Installation of Green Alley for Stormwater Research

The alley is to be retrofitted to include approximately 1520 sq. ft. of permeable interlocking pavers (PIP), an above-ground rainwater cistern with a volume of 2,000 gal., and approximately 620 sq. ft. of new non-permeable concrete surface. Demolition and removal of the current pavement shall be completed by the City of Wilson at the start of construction. The contractor will be responsible for all excavation and earth removal associated with the project. Silt fences and filter socks to control sediment erosion will be installed by the City of Wilson, but the contractor will be responsible for repairing or replacing these measures if necessary. The PIP shall be installed at grade spanning the width and length of the alley between 107 Douglas St S and 300 Nash St S in Wilson, NC 27893 as shown in Figures 1 and 2 (next page) and on the attached plan sheet. Concrete used as surface pavement in non-permeable areas shall be of a similar color to that of the chosen pavers. A nearby lay area will be provided by the City of Wilson for staging and storage of equipment and materials. Traffic control can be coordinated with the City of Wilson as needed. The PIP shall sit atop various layers of permeable bedding and base materials as specified in the attached plan sheet. The stone base layer shall be drained by a perforated PVC underdrain with cleanout valves, observation wells, and routed to Triton M-6 Chambers and to an existing stormwater catch basin (see attached plan sheet). The permeable pavement, underdrain, and observation wells shall be included in ongoing stormwater research at NC State University. The above-ground rainwater cistern shall be provided and installed by NC State atop the raised parking lot in the corner between the alley and the mural as indicated in Figure 1. The cistern shall be plumbed by the contractor to receive stormwater runoff from the adjacent. Cistern water shall be made available to irrigate the vegetated components of the green alley, and any overflow produced during large storm events shall be routed to the Triton M-6 Chambers below the PIP. The contractor is responsible for full clean up and proper off-site disposal of any construction debris and residual material. All trash shall be cleaned up daily. Excess earth shall be wasted and stabilized with seeding (temporary and permanent) and mulching on site before demobilization and final acceptance by the University. Sediment shall be prevented from being transported off site by stormwater runoff throughout the project (see attached plan sheet). Building foundations shall be protected throughout construction from hazards posed by excavation and underground water storage. All bids shall include (1) PIP design (paver selection, paver dimensions/properties, properties of bedding and base materials), (2) rainwater cistern design (cistern selection, connection to rooftop drainage, access for irrigation, overflow plumbing to Triton M-6 Chambers), and (3) total costs (e.g., materials, erosion control, delivery, installation, etc.)

Division 03 -	Concrete, Precast Concrete.
Division 31 -	Earthwork, Erosion and Sedimentation Controls.
Division 33 -	Utilities, Storm Drainage Utilities, Storm Utility Drainage Piping, Storm Utility Water Drains, Ponds and Reservoirs, Storm Drainage Structures.