SW6200502_Stormwater Narrative_20241003

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T I M M O N S GROUP Raleigh, NC 27607 www.timmons.com
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August 12, 2024
NC Dept of Enviro. Quality
Raleigh Regional Office
Attn: Brianna Holland
512 N. Salisbury Street
Office 625 Y
Raleigh, NC 27604
Subject: Stormwater Narrative and Construction Sequence
Project Name: Winder Station at Vass (SW6200502)— Major Modification
County: Moore
City: Vass
Dear Ms. Holland,
The proposed 72 lot single family subdivision, Winder Station at Vass, will be constructed as one project
with (3) three proposed Wet Pond SCM. The site is zoned R-1 and will be served by public water and
sanitary sewer systems.
SCM #1, #2, and #3 will be constructed to reduce the pre- to post-development peak flows conditions for
the 10-, 25-year, 24-hour storm event of the proposed development. Additionally, this project will
propose an 85% Total Suspend Solids removal and will treat the required Water Quality Volume per
NCDEQ requirements.
A pre-development and post-development hydrologic analysis was completed for the site using the
NRCS (SCS) method. A hydraulic analysis was completed using Hydraflow modeling software to route
the 1, 2, and 10 year storm events through the proposed detention and outlet structures.
This Major Modification to SW6200502 proposes 2 additional lots (north of existing lot 60) and open
space will be constructed as one project and will drain to SCM 3. The increase in BUA was analyzed as
part on the stormwater impact analysis and SCM 3 was found to still be adequate to handle the increase.
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