SW3240701_Stormwater Narrative_20240724

QT Store #1069 - Marshville, NC
STORMWATER MANAGEMENT NARRATIVE:
The site is on a proposed 3.32-acre lot located at the southwest corner of the intersection between
Marshville Boulevard and White Street in Marshville, NC. The proposed parcel encompasses four
existing parcels that will be combined into a single lot. The site is currently comprised of multiple
commercial buildings, associated parking, and assortment of grassland and trees. In the existing
conditions, the site drains to an existing ditch flowing southeast through the middle of the lot and
also to an existing catch basin along White Street. The property will be developed into a±5,312 square
foot convenience store building, gas canopy, diesel canopy, associated parking, and landscaped areas.
Per FEMA map #3710549500J the site is located in flood zone 'X'.
The project site is located in the Yadkin Pee-Dee River Basin, which is a sub-basin of the French
Broad River. Stormwater runoff from the site will discharge into a classification 'C' receiving water,
Lick Branch. An underground detention system in conjunction with an above ground detention pond
will be constructed to provide storm water management for the proposed QuikTrip. Discharge from
the detention system has been designed to meet the requirements of the Town of Marshville and
NCDENR. Detention will be designed to attenuate the 1-yr, 2-yr, 10-yr, 24-hour storm events and
reduce the developed peak flow rates to pre-development peak runoff rates. In addition, a
proprietary water quality device will be employed to achieve water quality requirements per Town of
Marshville for the proposed improvements.
Detention and ponding calculations for this site were completed with Hydraflow Hydrographs using
the SCS Method. Rainfall data was taken from the NOAA precipitation data frequency server. Per
NRCS Web Soil Survey, the site is comprised of Badin-Urban land complex (H5G D) and Cid-Urban
land complex (H5G C). As such, curve numbers affiliated with H5G D were employed for calculations.