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Home My WebLink AboutSW3220301_Supplement-EZ Form_20220420SUPPLEMENT-EZ COVER PAGE FORMS LOADED PROJECT INFORMATION 1 Project Name Surface Water Area (ac) Is this project High or Low Density? Does this project use an off -site SCM? Mini Storage USA, Inc - Mini Warehouse Project 1.95 - - High No NUMBER AND TYPE OF SCMs: 11 Infiltration System 12 Bioretention Cell — 13 Wet Pond 14 Stor mwater Wetland 15 Permeable Pavement 16 Sand Filter _ 1 17 Rainwater Harvesting RWH _ 18 Green Roof 19 Level Spreader -Filter Strip LS-F) 20 Disconnected Impervious Surface (DIS) 21 Treatment Swale 22 Dry Pond 23 StormFilter 24 Silva Cell 25 Bayfifter v— FORMS LOADED DESIGNER CERTIFICATION _ 27 Name and Title: _ _ Kevin E. Herring PE _ 28 Organization: �T _ _ Kevin E. Herring Engineering 29 Street address: 16101 Silver Rd 30 City, State Zip: OakboroNC 28129 31 Phone numbers : 980-621-0935 32 Email: _ kevin kevinheningengineedng.com Certification Statement: I certify, under penalty of law that this Supplement-EZ form and all supporting information were prepared under my direction or supervision; that the information provided in the forth is, to the best of my knowledge and belief, true, accurate, and complete; and that the engineering plans, specifications, operation and maintenance agreements and other supporting information are consistent with the information provided here. �`�>>i��irrrrrri :0. FESSPpN'�'9 SEAL -_ 20165 - '�r„rrrr,,,,, Sig at a of Designer LIZ z z Date DRAINAGE AREAS 1 Is this a high density project? Yes 2 If so, number of drainage areas/SCMs 1 3 Does this project have low density areas? No 4 If so, number of low density drainage areas 0 Is all/part of this project subject to previous rule 5 versions? No FORMS LOADED -DRAINAGE AREA INFORMATION Entire Site 1 4 Type of S C M Sand Filter Sand Filter 5 Total drainage area (sq ft) 84735 66130 6 Onsite drainage area (sq ft) 80825 62220 7 Offsite drainage area (sq ft) 3910 3910 8 Total BUA in project (sq ft) 56830 sf 56830 sf All Impervious area on proposed Site is contained within the New BUA on subdivided lots (subject to permitting), DA Of the SCM 9_ (sq ft) proposed P New BUA not on subdivided lots (subject to 10 permitting) (sf) 11 Offsite BUA (sq ft) 3140 sf 3140 sf Existing and Proposed Impervious area within DOT R/W 12 Breakdown of new BUA not on subdivided lots: Parking (sq ft) 31170 sf 31170 sf Sidewalk (sq ft) 350 sf 350 sf i Roof (sq ft) € 21850 sf 21850 sf Roadway (sq ft) # Future (sq ft) _ Other, please specify in the comment box below Concrete Accessible Parkin area (sq ft) 320 sf 320 sf g New infiltrating permeable pavement on subdivided' 13 lots (sq ft) New infiltrating permeable pavement not on 14 subdivided lots (sq ft) Existing BUA that will remain (not subject to 15 permitting) (sq ft) 16 Existing BUA that is already permitted (sq ft) 17 Existing BUA that will be removed (sq ft) 3520 sf 3520 sf Exist BUA to be removed includes the existing buildings and 18 Percent BUA 19 Design storm (inches) 67% 1.0 in 86 1.0 in gravel driveway on the property 20 Design volume of SCM (cu ft) 4538 cf 4538 cf 21 Calculation method for design volume Simple Simple ADDITIONAL INFORMATION Please use this space to provide any additional information about the 22 drainage area(s): See CN caics for speck breakdown Roadway includes existing Hwy 74 and new paved entrance Other includes the ADA concrete paved area - 320sf SAND FILTER 1: Drainage area number 1 2 Minimum required treatment volume cu ft�».. 4538 sf WQV=4538cf, WQVadj=3403cf 3 Is the SCM sized to treat the SW from all surfaces at build -out? Yes 4Is the SCM located away from contaminated soils? Yes 5' What are the side slopes of the SCM (H:V)? 6 Does the SCM have retaining walls, gabion walls or other NO engineered side slopes? Are the inlets, outlets, and receiving stream protected from erosion 7(10-year Yes storm)? 8' Is there an overflow or bypass for inflow volume in excess of the Yes design volume? 9 What is the method for dewatering the SCM for maintenance? Pump (preferred) 10If applicable, will the SCM be cleaned out after construction? Yes 11 Does the maintenance access comply with General MDC (8)? Yes 12' Does the drainage easement comply with General MDC (9)? Yes 13' If the SCM is on a single family lot, does (will?) the plat comply with N/A General MDC (10)? 14 Is there an O&M Agreement that complies with General MDC (11)? Yes 15 Is there an O&M Plan that complies with General MDC (12)? Yes 16 Does the SCM follow the device specific MDC? Yes Ref SHWT Re '---'port - No Evidence found. Auger refusal 18 SHWT elevation (fmsl) N/A p g _._ 19 Type of sand filter (open or closed) open 553.5+/- (2ft below proposed bottom of sand filter) 20 If closed, will the filter will be pre -cast or pour -in -place? 21 If closed, top of grate elevation (fmsl) _ a 22' Is this sand filter designed to attenuate peak flows? Yes Chamber 23 Volume that can be retained in the sediment chamber (cubic feet) ! 3336 cf 24 Will there be a permanent pool in the sediment chamber? No 25!Bottom of the sediment chamber (fmsl) 557.80 26 Area of the sediment chamber (square feet) 2910 sf 27 Physical depth of the sediment chamber (inches) 18 in 28 Ponding depth in the sediment chamber, above any permanent pool (inches) 29 Elevation of top of weir between chambers (fmsl) 559.3 30 Volume that can be retained in the sand chamber (cubic teet) iau cr 31 Bottom of the sand chamber (fmsl) 555.50 32' Area of the sand chamber (square feet) 520 sf 33' Physical depth of the sand chamber (inches) 18 in Ponding depth in the sand chamber, above the sand surface 18 in 34 (inches) 35 Elevation of the bypass device (fmsl) 559.3 36 Type of bypass device Outlet Structure 37 Mechanism for distributing flow over the sand surface Weir 38'Sand specification for sand chamber ASTM C33 39 Depth above underdrain pipe (inches) 12 in 40 Will the media be maintained to drain at least two inches per hour at Yes the sand surface? 41 Is at least one clean -out pipe provided at the low point of each Yes underdrain line? 42 Will clean -out pipes be capped? Yes Please use this space to provide any additional information about 43;the sand filter(s): Pump can be used but removeable cap is spec'd on outlet structure at id elevation. Ref Hydrocad Storage output. 4116cf at 559.3 (outlet weir elev) less sand filter vol of 780cf (520sf x 18") Ref Hydrocad Storage output. 3430sf at 559.3 (outlet weir elev) less sand filter area of 520sf 780cf = 520sf x 18" Elev of 18"x8" outlet orifice Riprap berm Sand Filter 1 7:22 PM 2/11/2022