Pratt Industries - 20181105 - Pratt Corrugating Stormwater Narrative

STORMWATER NARRATIVE

Pratt Corrugating – Building Addition

Statesville, NC

November 2018

W. K. Dickson & Co., Inc. 616 Colonnade Drive Charlotte, North Carolina 28205 [phone] NC License No. F-0374
GENERAL Pratt Corrugating is manufacture facility that specialize in the manufacturing of corrugated cardboard. Pratt Corrugating is located in Statesville, NC at 185 Deer Ridge Drive. The manufacturing facility is located on one existing parcel that is approximately
21.79 acres. The property is located within a NCDEQ classified Urbanizing Area/Phase II
MSI.

PROPOSED IMPROVEMENTS Pratt Corrugating plans to add a building addition to the north side of its main facility.
The estimated start of construction is December 2018. The proposed building is
approximately 55,218 sqft. The building will be accessed by an existing paved drive isle.
In addition to the building expansion, two (2) additional parking lot as proposed with a
total of 38 additional parking stalls. These parking lots are located in the southwest side
of the parcel and will be accessed by an existing drive isle. The proposed improvements generate an additional 88,916 sqft. of impervious area. As part of this expansion a total of 36,500 sqft. of impervious area is being removed for a net increase of 52,416 sqft. The proposed BMP is designed to treat an impervious area of 125,196 sqft., which is above the additional impervious area being created of 52,416 sqft. Given the existing storm drainage system and the roof drains on the existing building, the BMP pond treats existing and proposed impervious area from the existing and proposed building as well as the existing loading dock area and drive isle. Per conversations with Corey Anen at NCDEQ, this is acceptable so long as we are treating at minimum the same area of new impervious area be added. The two additional parking lots will sheet flow into the existing storm drainage system. The existing storm drainage system have been checked to ensure that they can handle the additional flow generated from the proposed parking lots as shown in the calculations prepared by W.K. Dickson.