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Home My WebLink AboutSW1221101_Design Calculations_20221110STORMWATER MANAGEMENT PLAN REVIEW PACKAGE 10/11/2022 TABLE OF CONTENTS PROJECT DESCRIPTION EXHIBIT A —SO IL DATA (NRCS) EXHIBIT B — RAIN DATA EXHIBIT C — TR-55 REPORTS L10lot l 1111-m rrl"[ole1�ilgWeviIorkRi - SCM SIZING & STORAGE VOLUME - TREATMENT & ATTENUATION - WEIR SIZING - PIPE SIZING - DRAWDOWN CALCULATIONS & ORIFACE SIZING PROJECT DESCRIPTION PROJECT NAME: JONAS RIDGE CONVENIENCE CENTER AND PARK, PHASE 1 PROJECT LOCATION: 8436 NC 181, NEWLAND, 28657 BURKE COUNTY PROPERTY PIN(S): 1841477773, 1841479393, 1841477430 LATITUDE: 35' 57'39.7" N LONGITUDE: -82° 53' 23.9" W RECEIVING WATERS: JOE BRANCH, CATAWBA RIVER BASIN NARRATIVE: Burke County is adding a transfer station on property owned by the county. Located off of HWY 181 in Jonas Ridge, the existing flat topography and ease of access make the site convenient for such a use. The site, as it exists now, has an abandoned house, pole barn, a small barn, and a gravel loop drive. These structures will be removed during site preparation/construction. From a stormwater perspective, there are no current resources in the project area, however Equinox has identified, and survey picked up a small pond just off property. In addition, hydrologically, the pond empties into a large wetland/bog, colloquially known as "Jonas Ridge Bog". The waters from the bog feed into Joe Branch, which feeds into Upper creek, as well as likely feeding directly into Upper creek, which is identified on the USGS map. The waters described above are classified as Outstanding Resource Waters (ORW), High Quality Waters (HOW), and Water Supply (WS-III). Equinox Environmental has visited the site with its lead ecologist and lead wildlife biologist, both certified to identify and delineate wetlands and noted the incredible resource. Due to the incredible qualities of the waters of this watershed and the adjacent bog, Equinox Environmental is proposing a stormwater treatment design (constructed wetland) that best mimics the existing adjacent condition and treats at a minimum the required volume of water, however, is sized to treat as much as the available space would allow. Calculations indicate that the constructed wetland will treat more than the first inch of rain and will attenuate up to the 10yr storm event. The site is graded, such that all the transfer station pad, parking, and 85% of the total impervious are drains to the constructed wetland, noted in the application as SCM 1. Efforts were made to capture as much of the impervious surface as possible. As seen on the drainage map, on sheet L2.0, the stormwater off the transfer station pad is designed to flow into a treatment swale to collect the stormwater and provide some initial treatment. The treatment Swale is heavily planted with species appropriate to slow and treat the water prior to it entering SCM1. From there, sheet flow from the parking area enters the system and joins most of the impervious surface stormwater runoff, entering the forebay of SCM1. SCM1 is designed and planted to maximize treatment, including efforts to extend the hydrologic flow path (See stormwater sheets and details). SCM1 and the feeding swale were designed to maximize all available space and collect and treat stormwater sheet flow as early as possible. OSl0®" MLODM 09MME 03MBEC CSS6LSE; OOmac M� TW x W M.EERS .19 x m G OSBBL6E M.TT,Eg To I N C7 N w O O N r n 4) N � 1+ R TL et v y, N N � UT U y U a .Q P3 m Uo � r, o Z a rn x e S d F a 4 C ry O O 17S a n n U) R o o� m of _ v zQ C Z V M,EE ES a1B QI Z)6 O O O O N D N 'C D m a C .? Gl QI O U N ro I O O y= C tab E v V) v-E E-0 7 N No N cY E O O � ?W L y D ro ron E N __ U E 0 co y L C7 i! ro Cy CD 2 O' C I.,- y l6 d) Vi roil y 41 O N L Z N O N V E v7 •O U a 0, .0 ro UN 3 a D E N. OIE 0) C GTlV D L n= `- Zc CD mND41 - Q ) O O 4) N m G.Vfca E C o�g o T C U vm D Eo- C Q a O E T U1 E D 7 y U 'o y w 1 U O Cl c •Q D ro uoroi ° v 2 0 o-a a D y W (D s E� c 14 7 J m U7 m Q C y Q r6 m> L y L C o v D Z� E E v a lC SO O N� ro d v t9 -= ID C o a)S `m a m Wm N o a w o. O C ro sn D i U C Oro co'C 0,0 ro C d 7 E O CCU EE@ c� 3L vD ¢ o`O D - oro� E O `7 'o V�� O Gl N p D � N m CD � L 'P. C_ O N l9 ra L `O N C7 O_ �- v U D y L _ E C _-. O � 4? N O 61 O E '.�- D D E: E O D O u) U N O` rn L O n a d ro L F o 0 3 a) O 47 u) .- ro p 0 N ro t O E_ H U ._ y N N O. lL (} L r U) YO y J v m � U1 u O w 0 O1 O N n ¢co u E .0 o a rn m L D a rn ' (nn c a x R a¢ R C CR O � � r R m O Q N tm 0 y di o c N a- y w a J o a N w E E a v � 0ar °n w O 00 a LL aN w c a . LYm a O O U) U) 0 O D m L a U (9 0 R JJ 7 R 0) C R U } 0 U] U U) La Ua)G a c m a 1 e ek fit' m Li Q U) E Q4 ro Z Soil Map —Burke County, North Carolina Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI NkA Nikwasi loam, 0 to 3 percent slopes, frequently flooded 8.4 31.2% NnE Northcove very cobbly loam, 30 to 50 percent slopes, rubbly 0.2 0.8% SsC Stecoah-Soto complex, 8 to 15 percent slopes, stony 17.0 63.5% SsD Stecoah-Saco complex, 15 to 30 percent slopes, stony 1.2 4.5% Totals for Area of Interest 26.8 100.0% USDA Natural Resources Web Soil Survey 7/27/2022 r Conservation Service National Cooperative Soil Survey Page 3 of 3 Map Unit Description: Stecoah-Soco complex, 8 to 15 percent slopes. stony ---Burke County, North Carolina Burke County, North Carolina SsC—Stecoah-Soco complex, 8 to 15 percent slopes, stony Map Unit Setting National map unit symbol: 3xs1 Elevation. 1,500 to 4,000 feet Mean annual precipitation: 40 to 55 inches Mean annual air temperature: 46 to 57 degrees F Frost -free period. 124 to 176 days Farmland classification: Not prime farmland Map Unit Composition Stecoah, stony, and similar soils: 60 percent Soco, stony, and similar soils: 30 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Stecoah, Stony Setting Landform: Mountain slopes, ridges Landform position (two-dimensional): Summit, backslope Landform position (three-dimensional): Upper third of mountainflank, side slope Down -slope shape: Convex Across -slope shape: Linear Parent material., Creep deposits over residuum weathered from phyllite and/or slate Typical profile A - 0 to 4 inches: channery loam 8w - 4 to 28 inches: channery fine sandy loam C - 28 to 50 inches: channery fine sandy loam Cr - 50 to 80 inches: weathered bedrock Properties and qualities Slope: 8 to 15 percent Surface area covered with cobbles, stones or boulders. 0.1 percent Depth to restrictive feature: 40 to 60 inches to paralithic bedrock Drainage class: Well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat): Moderately high (0.20 to 0.57 inlhr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water supply, 0 to 60 inches: Moderate (about 6.8 inches) Interpretive groups Land capability classification (irrigated): None specified usDA Natural Resources Web Soil Survey 7/2712022 Conservation Service Nalional Cooperative Soil Survey Page 1 of 2 Map Unit Description: Stecoah-Saco complex, 8 to 15 percent slopes, stony --Burke County, North Carolina Land capability classification (nonirrigated): 3e Hydrologic Soil Group: A Hydric soil rating: No Description of Soco, Stony Setting Landform: Mountain slopes, ridges Landform position (two-dimensional): Summit, backslope Landform position (three-dimensional): Upper third of mountainflank, side slope Down -slope shape: Convex Across -slope shape. Linear Parent material: Creep deposits over residuum weathered from phyllite and/or slate Typical profile A - 0 to 7 inches: channery loam Bw - 7 to 15 inches: fine sandy loam BC - 15 to 35 inches: channery fine sandy loam Cr - 35 to 80 inches: weathered bedrock Properties and qualities Slope: 8 to 15 percent Surface area covered with cobbles, stones or boulders: 0.1 percent Depth to restrictive feature. 20 to 40 inches to paralithic bedrock Drainage class. Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately high (0.20 to 0.57 in/hr) Depth to water table. More than 80 inches Frequency of flooding: None Frequency of ponding. None Available water supply, 0 to 60 inches: Low (about 4.7 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 4e Hydrologic Soil Group: B Hydric soil rating: No Data Source Information Soil Survey Area: Burke County, North Carolina Survey Area Data: Version 30, Jan 21, 2022 usDA Natural Resources Web Soil Surrey 7/27/2022 Conservation Service National Cooperative Soil Survey Page 2 of 2 EXHIBIT B Jason Jonas Ridge PRE Burke Mountain NOAA County, North Carolina Storm Data Rainfall Depth by Rainfall Return Period 2-Yr 5-Yr 10-Yr 25-Yr 50-Yr 100-Yr 1-Yr (in) (in) (in} (in) (in) (in) (in) --------------------------------------------------------------------------------- 3.89 4.96 5.82 7.03 8.04 9.1 3.2 Storm Data Source: Burke Mountain NOAA County, NC (NRCS) Rainfall Distribution Type: Type II Dimensionless Unit Hydrograph: <standard> WinTR-55, Version 1.00.10 Page 1 10/11/2022 11:35:25 AM E X H I B I T C WinTR-55 Current Data Description --- Identification Data --- User: Jason Date: 10/11/2022 Project: Jonas Ridge Units: English SubTitle: POST Areal Units: Acres State: North Carolina County: Burke Mountain NOAA Filename: Z:\ED\SP&D\McGill Jonas Ridge Phase 1\Permitting\Calculations\Jonas Ridge.w55 --- Sub -Area Data --- Name Description Reach Area(ac) RCN Tc ------------------------------------------------------------------------------ Transfer S Outlet 1.22 86 0.100 Total area: 1.22 (ac) --- Storm Data -- Rainfall Depth by Rainfall Return Period 2-Yr 5-Yr 10-Yr 25-Yr 50-Yr 100-Yr I-Yr (in) (in) (in) (in) (in) (in) (in) ------------------------------------------------------------------------------- 3.89 4.96 5.82 7.03 8.04 9.1 3.2 Storm Data Source: Burke Mountain NOAA County, NC (NRCS) Rainfall Distribution Type: Type II Dimensionless Unit Hydrograph: <standard> WinTR-55, Version 1.00.10 Page 1 10/11/2022 11:42:42 AM Jason Jonas Ridge PRE Burke Mountain NOAA County, North Carolina Watershed Peak Table Sub -Area Peak Flow by Rainfall Return Period or Reach 25-Yr 1-Yr Identifier (cfs) (cfs) ------------------------------------------------------------------------- SUBAREAS Transfer S 4.59 1.33 REACHES OUTLET 4.59 1.33 WinTR-55, Version 1.00.10 Page 1 10/11/2022 11:36:53 AM E-Y- ID T la . . . . . . . .Sail ' . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 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Elevation (ft) IV w .p cn rn -4 oo c4 0 0 0 0 0 0 0 0 0 0 T cn Pi 0 IV Gl 0 i !I i i F I n O �J UG O n � c q CL �G n � CD no C d d CD CD 00 n UU3 !� CD 00 HY-8 Analysis Results Culvert Summary Table - Culvert 1 (24") Culvert Crossing: Jonas Ridge SCM outfall Total Dischar ge (cfs) Culvert Dischar ge (cfs) Headwa ter Elevatio n (ft) Inlet Control Depth(ft) Outlet Control Depth(ft) Flow Type Normal Depth (ft) Critical Depth (ft) Outlet Depth (ft) Tailwate r Depth (ft) Outlet Velocity (fUs) Tailwate r Velocity (ftls) 3.33 3.33 92.87 0.87 0.47 1-S2n 0.50 0.64 0.52 0.13 5.13 12.52 4.14 14.14 92.98 10M 0.56 1-S2n 0.56 10.71 X59 10.15 5.41 2.75 4.95 4.95 93.10 11.10 0.65 1-S2n 0.61 10.78 0.65 0.17 5.65 2.95 5.76 5.76 93.21 11.21 0.74 1-S2n 0.66 0.85 Q.70 0.18 5.86 3.13 6.57 6.57 93.31 1.31 0.82 1-S2n 0.71 0.91 0.76 0.20 6.05 3.30 7.38 7.38 93.41 1.41 0.91 1-S2n 0.75 0.97 0.81 0.21 .23 3.45 8.20 8.20 93.50 1.50 1.00 1-S2n 0.80 1.02 0.86 0.23 .39 3.59 9.01 9.01 93.59 1.59 1.09 1-82n 0.84 1.07 0.90 0.24 6.55 3.72 b.77 9.77 3.67 1.67 1.17 1-S2n 11-S2n .88 1.12 0.95 0.25 6.68 3.84 10.63 111.44 10.63 93.76 1.76 1.27 1-S2n 0.92 1.17 0.99 0.27 6.83 3.97 11.44 93.85 1.85 1.37 0.96 1.21 1.04 0.28 16.97 V.09 ;Ascrl . . . . . . . . . . . ........... 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