Loading...
HomeMy WebLinkAbout20080845 Ver 1_Stormwater Info_20080519Stormwater Impact Analysis - Construction Drawing Submittal For the proposed White Deer Park Garner, North Carolina Prepared for OBS Landscape Architects Land Planners Prepared By Stewart Engineering, Inc. STEWART March 20, 2008 Revised April 28, 2008 ??? MAY f; 2008 ftTLANDSAND ST O1 R LlUAj7 INWATER BPANGH Stormwater Impact Analysis For White Deer Park Garner, North Carolina Prepared for: OBS Landscape Architects Land Planners Prepared by: Stewart Engineering, Inc. 421 Fayetteville Street, Suite 400 Raleigh, NC 27601 919.380.8750 `,`111111111/1,/ Q _ s??L _ 70? 0333,7 Z PRELIMINARY - FOR REVIEW PURPOSES ONLY Stewart Project No. C7005 March 20, 2008 Revised April 28, 2008 f Stormwater Impact Analysis WHITE DEER PARK GARNER, NORTH CAROLINA EXECUTIVE SUMMARY This Stormwater Impact Analysis has been prepared specifically to address the requirements of the Town of Garner Stormwater Management Ordinance (Article 7, Section 7.2 of the Unified Development Ordinance), in order to quantify the impact of the proposed development upon downstream systems. Per the Town of Garner Stormwater Management Ordinance, the post-development peak flow rate for the 1-, 10-, 25-year, 24-hour storm events must be held to that of pre- development conditions. The Total Nitrogen Export for the site must also be held to 3.6 lb/ac/yr. As is detailed below, the post-development peak flow rate in each storm of interest remains equal to that of the per-development condition due to the large overall drainage basin (1304.71 ac). The pre-development Total Nitrogen Export is calculated as 2.17 Ib/ac/yr where as the post-development is to 2.16 lb/ac/yr. Given that the post-development export is less than 3.6 Ib/ac/yr without the use of BMPs, no buydown payment will be required for this project. Site Information The White Deer Park site is located at the intersection of Buffaloe and Aversboro Roads in Garner. The existing site is mostly wooded but does include two substantial open areas. The project site is located in the southeast corner of a 91.41 ac parcel with a project area of approximately 25.50 ac. Existing impervious area on the site is 0.38 ac. The site lies within the Neuse River Basin along with the Lake Benson Conservation District. Per FEMA FIRMs 3720170003 and 37201710003, the site contains a 100-yr floodplain associated with a tributary to Reedy Creek. The Wake County Soil Survey Map indicates the soils on site consist primarily of Cecil sandy loams which are classified as Hydrologic Soil Group B. The project area also contains two existing intermittent streams, one of which runs long the northwest boundary of the project area and one that splits the project area from west to east. Both stream corridors will be protected with 50' Neuse River Buffers. Portions of each stream are also buffered with a 90' Lake Benson Watershed Conservation Buffer. Proposed Improvements The proposed development on the site will include a nature center (2500 sf), restrooms, learning terrace, picnic shelters, playground areas, entry drive, site roads, and parking lots. The site improvements will add 4.02 ac of additional impervious area for a total proposed impervious area of 4.40 ac or 4.81% (based upon parcel area). Stormwater from the majority of the proposed parking areas will be captured and treated in one of four bioretention areas. Each bioretention area has been sized to capture the portion of parking area which drains to it and is equipped with underdrains. As is described in the Design Procedure and Overall Results portions of this report, these BMPs are not required to meet either the Peak Flow or Nitrogen Export portions of the Town of Garner Stormwater Management Ordinance. Design Procedure The analysis point for the Peak Flow Analysis portion of the report is taken as the point where drainage from the project area leaves the site. This point happens to be the point at which the tributary to Reedy Creek existing the parcel (along the southwestern property boundary). The total drainage area (including offsite areas) to this point is approximately 1305 ac. The peak flow at this point is determined by using the SCS Hydrograph Formulation Method. The cover conditions for the project area is based upon the actual site conditions where as the offsite areas are based upon their current zoning. The Time of Concentration for the drainage area is determined using the method outlined in USDA TR-55. Due to the fact that the overall drainage area is significantly large in comparison to the project area, the increase in impervious area caused by development of the site does not increase the Curve Number. The Time of Concentration remains the same as well. Therefore, there is no increase in peak flow at the point of discharge off the site. The pre- and post-development Total Nitrogen Export is calculated for the parcel area using the Town of Garner worksheet. Overall Results The results from the peak flow analysis and Total Nitrogen Export calculations are below. Note that the peak flow analysis is based upon the overall drainage area and associated cover conditions where as the Total Nitrogen Export calculations are based upon the parcel area. Please see the corresponding appendices for detailed calculations. Peak Flow Analysis The table below shows the pre- and post-development peak flow for the 1-, 10-, and 25-year, 24-hour storm events. As is shown, the peak flow in the post- development condition is equal to that of the pre-development condition for each storm event. Peak Flow Analysis 1-yr 10-yr 25-yr Drainage Curve Peak Percent Peak Percent Peak Percent Area Number Flow Increase Flow Increase Flow Increase ac cfs cfs cfs Existin 91.41 70 261.83 974.10 1416.41 Proposed 91.41 70 261.83 0.00% 974.10 0.00% 1416.41 0.00% Total Nitrogen Export The pre-development Total Nitrogen Export for the parcel (91.41 ac) is 2.17 Ib/ac/yr with a post-development export of 2.16 lb/ac/yr. This is below the allowable export of 3.6 lb/ac/yr. Conclusions Based upon the results of this analysis shown above, the requirements Town of Garner Stormwater Management Ordinance as it pertains to Peak Flow and Total Nitrogen Export have been met for this project with no structural measures. Site Information TopoZone - USGS Lake Wheeler (NC) Topo Map age 1 of 1 0 0.1 0.2 0.3 0.4 0.5 km G 0 0.09 0.18 0.27 0.36 0.45 mi UTM 17 714799E 3950728N (NAD83/WGS84) USGS Lake Wheeler (NC) Quadrangle M=-8.795 Projection is UTM Zone 17 NAD83 Datum G=1.385 11.i?SAY 1 ?, 7n°?? http://www.topozone. com/print. asp?lat=3 5.67708&lon=-78.6265 8&s=24&size=l&u=4&1ayer=DRG25 &d... 3/18/2008 d u N ¦ n Scale 1:15640 (Join. 1 Mike s ?n 1 eel 1? #nrs At / 0? 7J7 Off; / O?G t _ i a, r , m f ZONE A 35.41'00 fleedy (reeR Irior<scary N r WHITHORNE_*DR o R. t ` Basin 20, Stream 9) St n? c r ' I•;. ZONE X 2c,2 r - w EZ 671 w % f aL ,? t0 6 fir' IW7JNNIA d 'tL IX- t E 007 248 ; 702 500 FEET n,' ??\ / * y 3951 000 M / `? r` P'te` ?Jc eF 99 y\/ y { a d?. 2¢8 ZONE X '"= tti nr. ,:. uJ 244 ...? SITE - : of Garner 2¢2 ji, Extraterritorial unt ?, - Jurisdiction Y=..:.; 370240 ed Areas Town. Hof. Garner `BEN 8` `Extraterritorial I ESIGN Z2670 CG c .iJurisdiction 370240 q ° °9 e° ZONE X ?'' ` OJFFP 't, *sS "PUMP NCGS EZ2669 ; d 35.40' 30 LLJ N, 4 GRID NORTH SCALE 1" = 500' (1 : 6,000) 0 500 1000 FEET PANEL 1710J FIRM FLOOD INSURANCE RATE MAP I NORTH CAROLINA PANEL 1110 (SEE LOCATOR DIAGRAM OR MAP INDEX FOR nRm PANEL LAYOUT) CONTAINS: I COMMUNITY CID No. PANEL SUFFIX GARNER. TOWN OF 37 Q 17M WAKE COUNT" 370369 17V NW w Jw* The Y9 ...Mr -- btl- -A a - w1w1 pl-,,g ms. ord- ee ea. 1tr s..". ,nowr wo ee uxa a appKaoms I— aunt- '. EFFECTIVE DATE MAP NUMBER MAY 2,1006 37201710001 f` A. s State of North Carolina Federal Emergency Management Agency is is an official copy of a portion of the abode referenced flood map. It ati extracted using F-MIT On-ine. This map does not reflect changes amendments which may ha%e been made subsequent to the date on the e block. For the latest product information about National Flood Insurance ogram flood maps check the FEMA Flood Map Store at www.msc.fema.gov AKE COUNTY ` \ ZONE X ZONE X "'. s 252\ CHRISTIAN RD ? 'z'q o ti I 248 ZONE X - Buck Branch a 20, Stream *12) 24y Wake County ?¢2 r Unincorporated Areas 370368.. ass ?39 ' Reedy Creek (Basin 20, Str oam 11) ZONE X s ?- ® BUFFALO NCGS' EZ2668 ` ONE X' T- $ 714 ow M 78.38'00" / ZONE A BUFFALOE RD (EL 238) AE - 3951 DW M -Beedy Creek (Basin 20, Stream 11) OZONE X ,Town of Garner Extraterritorial Jurisdiction 370240 35.40' 30" ?a Town of Garner 370240 700 000 FEET 2 110 000 FEET ZONE X 4 GRID NORTH SCALE 1" = 500' (1 : 6,000) 0 500 1000 FEET PANEL 1700J RM 100 INSURANCE RATE MAP )RTH CAROLINA EL 1700 LOCATOR DUIGRAM OR MAP INDEX FOR FlRM L LAYOUT) AINS: NUNITY CID No. PANEL SUFFD( ER. TOWN OF 370240 ']CO coUN ` 310388 '.M I Note to JW TM IMP NU.I.r 4- bebw -Id be used when placing mep orders: the C-"y N..b.r ahowr .1-d be geed on insurance wpaceocre lo- a.bt- '.. mrl,wni:v EFFECTIVE DATE MAP NUMBER MAY 2, 2006 31201700001 F IYV,??i tEr ?? A QJ State of North Carolina Federal Emergency Management Agency j This is an official copy of a portion of the above referenced flood map. It was extracted using F-MIT On-Line. This map does not reflect changes or amendments which may have been made subsequent to the date on the title dock. For the latest product information about National Flood Insurance Program flood maps check the FIRMA Flood Map Store at wvw. .. msc.feme.gov Appendix 5 Riprap Calculations STEWART RIPRAP OUTLET PROTECTION WORKSHEET Project White Deer Park Project No. C7005 Outlet ID Cv-1 Outlet flowrate 3.5 cfs Pipe diameter 12 inches Outlet pipe slope 1.31 percent Full flow velocity 4.5 ft/sec Figure 8.06.b.1 25 20 V 15 V 10 5 Zone from graph above = I Outlet pipe diameter 12 in. Outlet flowrate 3.5 cfs Outlet velocity 4.5 ft/sec Material = Class A Length = 4.0 ft. Width = 3.0 ti. Stone diameter = 3 in. Thickness = 9 in. Date 24-Apr-08 Designer ACP Zone Material Diameter Thickness Length Width 1 Class A 3 9 4 x D(o) 3 x D(o) 2 Class B 6 22 6 x D(o) 3 x D(o) 3 Class1 13 22 8 x D(o) 3 x D(o) 4 Class I 13 22 8 x D(o) 3 x D(o) 5 Class 11 23 27 10 x D(o) 3 x D(o) 6 Class II 23 j 27 10 x D(o) 3 x D(o) 7 Special stud required Calculations based on NY DOT method - Pages 8.06.05 through 8.06.06 in NC Erosion Control Manual 0 0 1 2 3 4 5 6 7 8 9 10 Pipe diameter (ft) CS RIPRAP OUTLET PROTECTION WORKSHEET Project White Deer Park Project No. C7005 Outlet ID CV-2 Outlet flowrate 8.1 cfs Pipe diameter 18 inches Outlet pipe slope 1.56 percent Full flow velocity 4.6 ft/sec Fieure 8.06.b.1 c a u 4 7 a STEWART Date 24-Apr-08 Designer ACP Zone 7 20 Z 6 one 15 Zone 5 10 Zone 4 5 Zone 1 ? _ ? Zone 3 y Zone 2 0 0 1 2 3 4 5 6 7 8 9 10 Pipe diameter (ft) Zone from graph above = 1 Outlet pipe diameter 18 in. Outlet flowrate S. I cfs Outlet velocity 4.6 ft/sec Material = Class A Length = 6.0 ft. Width = 4.5 ft. Stone diameter = 3 in. Thickness = 9 in. Zone Material Diameter Thickness Length Width 1 Class A 3 9 4 x D(o) 3 x D(o) 2 Class B 6 22 6 x D(o) 3 x D(o) 3 Class I 13 22 8 x D(o) 3 x D(o) 4 Class I 13 22 8 x D(o) 3 x D(o) 5 Class Il 23 27 10 x D(o) 3 x D(o) 6 7 Class 11 23 27 10 x D(o) Special stud required 3 x D(o) Calculations based on NY DOT method - Pages 8.06.05 through 8.06.06 in NC Erosion Control Manual ,Am STEWART RIPRAP OUTLET PROTECTION WORKSHEET Project Project No. Outlet ID White Deer Park C7005 CV-3 Date 24-Apr-08 Designer ACP Zone from graph above = Outlet pipe diameter 15 in. Length = 5.0 ft. Outlet flowrate 4.0 cfs Width = 3.8 ft. Outlet velocity 3.3 ft/sec Stone diameter = 3 in. Material = Class A Thickness = 9 in. Zone Material Diameter Thickness Length Width 1 Class A 3 9 4 x D(o) ! 3 x D(o) 2 Class B 6 22 6 x D(o) 3 x D(o) 3 Class I 13 22 8 x D(o) 3 x D(o) 4 ClassI 13 22 8 x D(o) 3 x D(o) 5 Class II 23 27 10 x D(o) 3 x D(o) 6 7 Class 11 23 27 j 10 x D(o) Special stud required 3 x D(o) Calculations based on NY DOT method - Pages 8.06.05 through 8.06.06 in NC Erosion Control Manual Outlet flowrate 4 cfs Pipe diameter 15 inches Outlet pipe slope 7.5 percent Full flow velocity 3.3 ft/sec I Apk- STEWART RIPRAP OUTLET PROTECTION WORKSHEET White Deer Park C7005 CV-4 18.6 cfs 24 inches 2.94 percent 5.9 ft/sec Zone from graph above = 2 Outlet pipe diameter 24 in. Outlet flowrate 18.6 cfs Outlet velocity 5.9 f /se Material = Class B Length = 12.0 ft. Width = 6.0 ft. Stone diameter = 6 in. Thickness = 22 in. Date 24-Apr-08 Designer ACP Zone Material Diameter Thickness Length Width 1 _Class A 3 _ 9 4 x D(o) 1 3 x D(o) 2 Class B 6- 22 6 x D(o) 3 x D(o) 3 Class I 13 22 8 x D(o) 3 x D(o) 4 Class I 13 22 8 x D(o) 3 x D(o) 5 Class 11 23 27 10 x D(o) 3 x D(o) 6 7 Class It 23 Spec 27 10 x D(o) ial stud required 3 x D(o) Project Project No. Outlet ID Outlet flowrate Pipe diameter Outlet pipe slope Full flow velocity Calculations based on NY DOT method - Pages 8.06.05 through 8.06.06 in NC Erosion Control Manual ?S STEWART RIPRAP OUTLET PROTECTION WORKSHEET Project White Deer Park Project No. C7005 Outlet ID CV-5 Outlet flowrate 0.95 cfs Pipe diameter 15 inches Outlet pipe slope 7.14 percent Full flow velocity 0.8 ft/sec Date 24-Apr-08 Designer ACP Figure 8.06.1).1 1 25 20 u 15 w ?V 10 5 Zone from graph above = 1 Outlet pipe diameter 15 in. Length = 5.0 ft. Outlet flowrate 1.0 cfs Width = 3.8 ft. Outlet velocity 0.8 ft/sec Stone diameter = 3 in. Material = Class A Thickness = 9 in. Zone I I Material Diameter Thickness Length Width I Class A 3 9 4 x D(o) 3 x D(o) 2 Class B 6 22 6 x D(o) 3 x D(o) 3 Class I 13 22 8 x D(o) 3 x D(o) 4 Class I 13 22 8 x D(o) 3 x D(o) 5 Class II 23 27 10 x D(o) 3 x D(o)_ 6 7 Class II 23 27 10 x D(o) 3 x D(o) Special stud required Calculations based on NY DOT method - Pages 8.06.05 through 8.06.06 in NC Erosion Control Manual 0 0 1 2 3 4 5 6 7 8 9 10 Pipe diameter (ft) STEWART RIPRAP OUTLET PROTECTION WORKSHEET Project White Deer Park Project No. 07005 Outlet ID CV-6 Outlet flowrate 5 cfs Pipe diameter 15 inches Outlet pipe slope 10.7 percent Full flow velocity 4.1 ft /sec Date 24-Apr-08 Designer ACP Fieure 8.06.b.1 25 20 U 15 'u 10 5 Zone from graph above = 1 Outlet pipe diameter 15 in. Length = 5.0 ft. Outlet flowrate 5.0 cfs Width = 3.8 ft. Outlet velocity 4.1 ft/sec Stone diameter = 3 in. Material = Class A Thickness = 9 in. Zone Material Diameter Thickness Length Width 1 Class A 3 9 4 x D(o) 3 x D(o) 2 Class B 6 22 6 x D(o) 3 x D(o) 3 ClassI 13 22 8 x D(o) 3 x D(o) 4 Class I 13 22 8 x D(o) 3 x D(o) 5 Class II 23 27 10 x D(o) 3 x D(o) 6 7 Class II 23 27 10 x D(o) Special stud required 3 x D(o) Calculations based on NY DOT method - Pages 8.06.05 through 8.06.06 in NC Erosion Control Manual 0 0 1 2 3 4 5 6 7 8 9 10 Pipe diameter (ft) STEWART RIPRAP OUTLET PROTECTION WORKSHEET Project White Deer Park Project No. C7005 Outlet ID CV-7 Outlet flowrate 3.2 cfs Pipe diameter 15 inches Outlet pipe slope 2.22 percent Full flow velocity 2.6 ft/sec Fieure 8.06.b.1 25 20 V 15 w V 10 5 0 0 Zone from graph above = l Outlet pipe diameter 15 in. Outlet flowrate 3.2 cfs Outlet velocity 2.6 tUsec Material = Class A Length = 5.0 ft. Width = 3.8 ft. Stone diameter = 3 in. Thickness = 9 in. Date 24-Apr-08 Designer ACP Zone Material Diameter Thickness Length Width 1 Class A 3 9 4 x D(o) 3 x D(o) 2 Class B 6 22 6 x D(o) 3 x D(o) 3 Class I 13 22 8 x D(o) 3 x D(o) 4 Class I 13 22 8 x D(o) 3 x D(o) 5 Class II 23 27 10 x D(o) 3 x D(o) 6 7 Class 11 23 27 10 x D(o) 3 x D(o) Special stud required Calculations based on NY DOT method - Pages 8.06.05 through 8.06.06 in NC Erosion Control Manual 1 2 3 4 5 6 7 8 9 10 Pipe diameter (ft) r S :w. STEWART RIPRAP OUTLET PROTECTION WORKSHEET Project White Deer Park Project No. 07005 Outlet ID CV-8 Outlet flowrate 28 cfs Pipe diameter 30 inches Outlet pipe slope 5.56 percent Full flow velocity 5.7 ft/sec Fieure 8.06.b.1 Zone from graph above = 2 Outlet pipe diameter 30 in. Outlet flowrate 28.0 cfs Outlet velocity 5.7 fUsec Material = Class B Length = 15.0 ft. Width = 7.5 ft. Stone diameter = 6 in. Thickness = 22 in. Date 24-Apr-08 Designer ACP Zone Material Diameter Thickness Length Width 1 Class A 3 9 4 x D(o) 3 x D(o) 2 Class B 6 22 6 x D(o) 3 x D(o) 3 Class 1 13 22 8 x D(o) 3 x D(o) 4 Class I 13 22 8 x D(o) 3 x D(o) 5 Class II 23 27 10 x D(o) 3 x D(o) 6 7 Class II 23 27 10 x D(o) Special stud required 3 x D(o) Calculations based on NY DOT method - Pages 8.06.05 through 8.06.06 in NC Erosion Control Manual ?S STEWART RIPRAP OUTLET PROTECTION WORKSHEET 1 2 3 Zone from graph above = I Outlet pipe diameter 15 in. Outlet flowrate 0.5 cfs Outlet velocity 0.4 ft/sec Material = Criss A 7 8 9 10 Length = 5.0 ft. Width = 3.8 ft. Stone diameter = 3 in. Thickness = r) in. Zone Material Diameter Thickness Length Width I Class A 3 9 4 x D(o) 3 x D(o) 2 Class B 6 22 6 x D(o) 3 x D(o) 3 Class I 13 22 8 x D(o) 3 x D(o) 4 Class I 13 22 8 x D(o) 3 x D(o) 5 Class II 23 27 10 x D(o) 3 x D(o) 6 Class II 23 27 10 x D(o) r 3 x D(o) 7 Special stud required Project White Deer Park Project No. C7005 Outlet ID CV-9 Outlet flowrate 0.52 cfs Pipe diameter 15 inches Outlet pipe slope 4.17 percent Full flow velocity 0.4 ft/sec Date 24-Apr-08 Designer ACP 25 20 V 15 w Z 10 5 0 0 Fisure 8.06.b.1 4 5 6 Pipe diameter (ft) Calculations based on NY DOT method - Pages 8.06.05 through 8.06.06 in NC Erosion Control Manual STEWART RIPRAP OUTLET PROTECTION WORKSHEET Project White Deer Park Project No. C7005 Outlet ID CV-10 Outlet flowrate 1.2 cfs Pipe diameter 15 inches Outlet pipe slope 0 percent Full flow velocity 1.0 ft/sec Figure 8.06.b.1 25 20 u I 15 I jr 'u 10 5 0 Zone from graph above = 1 Outlet pipe diameter 15 in. Outlet flowrate 1.2 cfs Outlet velocity 1.0 ft/sec Material = Class A Length = 5.0 ft. Width = 3.8 fi. Stone diameter = 3 in. Thickness = 9 in. Date 24-Apr-08 Designer ACP Zone Material Diameter Thickness Len th Width I Class A 3 9 1 4 x D(o) 3 x D(o) 2 Class B 6 22 6 x D(o) 3 x D(o) 3 Class I 13 22 8 x D(o) 3 x D(o) 4 Class I 13 22 8 x D(o) 3 x D(o) 5 Class II 23 27 10 x D(o) _ 3 x D(o) 6 7 Class 11 23 27 10 x D(o) Special stud required 3 x D(o) Calculations based on NY DOT method - Pages 8.06.05 through 8.06.06 in NC Erosion Control Manual 1 2 3 4 5 6 7 8 9 10 Pipe diameter (ft) 7?-- C STEWART RIPRAP OUTLET PROTECTION WORKSHEET Project White Deer Park Project No. 07005 Outlet ID CV-1 1 Outlet flowrate 0.6 cfs Pipe diameter 15 inches Outlet pipe slope 1 percent Full flow velocity 0.5 ft/sec Fieure 8.06.b.1 25 20 15 w Z -°? 10 5 Zone from graph above = 1 Outlet pipe diameter 15 in. Outlet flowrate 0.6 cfs Outlet velocity 0.5 ft/sec Material = Class A Length = 5.0 ft. Width = 3.8 ft. Stone diameter = 3 in. Thickness = 9 in. Date 24-Apr-08 Designer ACP Zone Material Diameter Thickness Length Width I Class A 3 9 4 x D(o) 3 x D(o) 2 Class B 6 22 6 x D(o) 3 x D(o) 3 Class1 13 22 8 x D(o) 3 x D(o) 4 Class 1 13 22 8 x D(o) 3 x D(o) 5 Class II 23 27 10 x D(o) 3 x D(o) 6 Class 11 23 27 10 x D(o) 3 x D(o) 7 Special stud required Calculations based on NY DOT method - Pages 8.06.05 through 8.06.06 in NC Erosion Control Manual 0 0 1 2 3 4 5 6 7 8 9 10 Pipe diameter (ft) f STEWART RIPRAP OUTLET PROTECTION WORKSHEET Project White Deer Park Project No. C7005 Outlet ID CV-12 Outlet flowrate 2.9 cfs Pipe diameter 15 inches Outlet pipe slope 0 percent Full flow velocity 2.4 ft/sec Fieure 8.06.b.1 Zone from graph above = 1 Outlet pipe diameter 15 in. Outlet flowrate 2.9 cfs Outlet velocity 2.4 ft/sec Material = Class A Length = 5.0 ft. Width = 3.8 T. Stone diameter = 3 in. Thickness = 9 in. Date 24-Apr-08 Designer ACP Zone Material Diameter Thickness Len th Width 1 Class A 3 9 4 x D(o) 1 3 x D(o) 2 Class B 6 22 6 x D(o) 3 x D(o) 3 Class I 13 22 8 x D(o) 3 x D(o) 4 Class I 13 22 8 x D(o) 3 x D(o) 5 Class II 23 27 10 x D(o) 3 x D(o) 6 Class II 23 27 10 x D(o) ! 3 x D(o) 7 Special stud required Calculations based on NY DOT method - Pages 8.06.05 through 8.06.06 in NC Erosion Control Manual STEWART RIPRAP OUTLET PROTECTION WORKSHEET Project White Deer Park Project No. C7005 Outlet ID FES-3 Outlet flowrate 7.79 cfs Pipe diameter 18 inches Outlet pipe slope 0.5 percent Full flow velocity 4.4 ft/sec Date 24-Apr-08 Designer ACP 25 20 15 ?u 10 5 Fiuure 8.06.b.1 Zone from graph above = 1 Outlet pipe diameter 18 in. Outlet flowrate 7.8 cfs Outlet velocity 4.4 ft/sec Material = Class A Length = 6.0 ft. Width = 4.5 ft. Stone diameter = 3 in. Thickness = 9 in. Zone Material Diameter Thickness Length Width 1 Class A 3 9 4 x D(o) 3 x D(o) 2 Class B 6 22 6 x D(o) 3 x D(o) 3 Class1 13 22 8 x D(o) 3 x D(o) 4 Class I 13 22 8 x D(o) 3 x D(o) 5 Class 11 23 27 10 x D(o) 3 x D(o) 6 7 Class 11 23 27 10 x D(o) 3 x D(o) Special stud required Calculations based on NY DOT method - Pages 8.06.05 through 8.06.06 in NC Erosion Control Manual 0 0 1 2 3 4 5 6 7 8 9 10 Pipe diameter (ft) ?S STEWART RIPRAP OUTLET PROTECTION WORKSHEET Project White Deer Park Project No. C7005 Outlet 1D FES-4 Outlet flowrate 5.73 cfs Pipe diameter 18 inches Outlet pipe slope 0.8 percent Full flow velocity 3.2 ft/sec 25 20 u 15 41 'v 10 5 0 0 1 2 3 Fieure 8.06.b.1 Date 24-Apr-08 Designer ACP 4 5 6 7 8 9 10 Pipe diameter (ft) Zone from graph above = I Outlet pipe diameter 18 in. Outlet flowrate 5.7 cfs Outlet velocity 3.2 ft/sec Material = Class A Length = 6.0 ti. Width = 4.5 ft. Stone diameter = 3 in. Thickness = 9 1,11. Zone Material Diameter Thickness Length Width 1 Class A 3 - 9 4 x D(o) 3 x D(o) 2 Class 6 22 6 x D(o) 3 x D(o) 3 Class 1 13 22 8 x D(o) 3 x D(o) 4 Class 1 13 22 8 x D(o) 3 x D(o) 5 Class 11 23 27 10 x D(o) 3 x D(o) 6 Class 11 23 27 10 x D(o) 3 x D(o) 7 Special study required Calculations based on NY DOT method - Pages 8.06.05 through 8.06.06 in NC Erosion Control Manual