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Home My WebLink AboutSW6170701 - Rolling Springs Section 8 (4)Rolling Springs Section 8 Storm Water Narrative This site is currently undeveloped although there is a power line crossing the property. The site is being developed as a single family residential development. The site drains to an existing wetland that lies to the south of the area being developed. The site meets the qualifications of a low density development. The average density for the development is 0.76 units/acre compared to the maximum of 2 units/acre to satisfy the requirements set forth by NCDEQ. The roads have open swales with 3:1 side slopes that convey the storm water. The roads in the subdivision were designed in accordance with NCDOT requirements. Based on our study and review of the NCDEQ BMP manual and NC Session Law 2006- 246 Section 9 paragraph c, Hidden Lakes Subdivision meets and/or exceeds the requirements and intent for low density development. 409 Chicago Drive, Suite 112, Fayetteville, NC 25306 office 1 910-426-6777 fax 1910-426-5777 On time, every time I www 4Dsitesolutions corn ROLLING SPRINGS SECTION 8 STORM WATER CALCULATIONS ts \SE L = 027452 = 0 OTT •• B . P % �6 DITCH MATTING CALCULATIONS DITCH #1 ® North American Green ECMDS Version 4.3 - Channel Protection Design, Output Form — ❑ X File Specifications Options Help ENGLISH JUSER 6/8/2017 0955AM HYDRAULIC RESULTS Discharge cfs Peak Flow Period his Velocity (fpsJ Area (sq ft) Hydraulic Radius ft Normal Depth ft 22 01 1 J8 1 49 0 33 063 LINER RESULTS Unremforced 5=00126 1 L� Bottom J 1 30 Width =050 ft 30 Not to Scale Matting Type Vegetation Characteristics Reach Stability Analysis Permissible Calculated Safety Factor Remarks Staple Pattern Phase Class Type Density Shear Stress Shear Stress (Psfl (Psf) I Straight Unre,nfoiced I Vegetation E Bunch I <500 216 049 439 STABLE Soil Sandy Loam 0 035 0 030 1 15 STABLE DITCH #2 E North American Green ECMDS Version 4.3- Channel Protection Design, Output Form x File Specifications Options Help ENGLISH, USER Fv-Bnow F5-9.56AMI -HYDRAULIC 56LT§: U nreinfoiced Vegetation (n=O 089) Discharge Peak Flow Velocity (fps) Area (sq ft) Hydraulic Normal fcfsl Period his Radius ft Depth (ft) Hydraulic Normal It De th 18 0.4 01 92 0.44 01 J S 0 0300 Bottom — 3,0 Width 0 50 It 30 Not to Scale '�11411ER'A�SUUTS Malting Type Vegetation Characteristics Reach Stability Analysis Permissible Calculated Safety Factor Remarks Staple Pattern Phase' Class Type Density Shear Stress Shear Stress I (Psf) (pst) I Straight Unfeinforced Vegetation E I Bunch 1 <50Z 2.16 057 376 STABLE Soil Sandy Loam 0035 1 0013 264 STABLE I 031 DITCH #3 North American Green ECMDS Version 4.3 - Channel Protection Design, Output Form 0 x File Specifications Options Help ,ENGLISH IUSER 1618/2017 1038 AM �HYDRAULII Alifsidm-, r, C125 (n=0 022) (t) (sqRHydraulic o Radius De e (cfs] I Period flysl I a lust 1 1 pth (ft) 44 01 642 S=00660 Bottom 30 Width 0 50 It 30 61 Not to Scale Discharge Peak Flow Velocity (fps) Area (s -Fttsum "'ONER" ft North American Green ECMDS Version 4.3 - Channel Protection Design, Output Form 0 x File Specifications Options Help ,ENGLISH IUSER 1618/2017 1038 AM �HYDRAULII Alifsidm-, r, C125 (n=0 022) (t) (sqRHydraulic o Radius De e (cfs] I Period flysl I a lust 1 1 pth (ft) 44 01 642 S=00660 Bottom 30 Width 0 50 It 30 61 Not to Scale Discharge Peak Flow Velocity (fps) Area (s -Fttsum "'ONER" ft DITCH #4 ® North American Green ECMDS Version 4.3- Channel Protection Design, Output Form — ❑ X File Specifications Options Help Velocity (fps) Area (sq.ft) ;ENGLISH. JUSER Normal Depth ft 6/8/2017 1040AM HYDRAULIC RESULTS 560 043 018 030 Discharge Peak flow Velocity (fps) Area (sq ft) Hydraulic Normal C125 (n=0 022) cfs Period (his) Radius ft Depth ft j?4 0 ' S = 0 0690 ' = '_ 1 1 - - _ �„ , L� Bottom �J 3 0 Width = 0 50 ft 3 0 H : LINER RESULTS '- - "- . - • ' a+ Not to Scale Matting Type Vegetation Characteristics Reach Stability Analysis Permissible Calculated Safety Factor Remarks Staple Pattern Phase Class Type Density Shear Stress Shear Stress (psi) (psf) Straight C125 Unvegetated 225 131 Peak Flow Period his Velocity (fps) Area (sq.ft) Hydraulic Radius ft Normal Depth ft 1216044 1 560 043 018 030 1 72 STABLE Staple D DITCH #1&2 ® North American Green ECMDS Version 4.3 -Channel Protection Design, Output Form — ❑ %< File Specifications Options Help ;ENGLISH. USER r 6/8!2017 lO42AM- -- -HYDRAULI ;s - CRESULTS' - -- - '' '�'-r'. •° - - --_ C125 (n=0022) t' Sr•. - _ :f, S=00760 _ Bottom ' 30 Width =050 It 30 - -LINER RESULTS - ' , " _ ; � ' - • - • - Not to Scale Matting Type Vegetation Characteristics_ Reach Stability Analysis Permissible Calculated Safety Factor Remarks _ Staple Pattern Phase Class Type Density Shear Stress Shear Stress (psf) (psf) Straight C125 Unvegetated 225 146 154 STABLE Staple D Discharge c(s Peak Flow Period his Velocity (fps) Area (sq.ft) Hydraulic Radius ft Normal Depth ft 1216044 016 031 DITCH #3&4 ® North American Green ECMDS Version 4.3 - Channel Protection Design, Output Form File Specifications Options Help 'ENGLISH. 1USER { 6/8/2017 1041 AM(^— .HYDRAULIC RESULTS Discharge efs Peak Flow Period (hrsl Velocity (fps) Area (sq (t) Hydraulic Radius ft Normal Depth ft �8 01 614 111 029 053 LINER RESULTS — ❑ X 3 Widthtto0 50 ft 3 Not to Scale h4atting Type Vegetation Characteristics Reach Stability Analysis Permissible Calculated Safety Factor Remarks Staple Pattern Phase Class Type Density Sheai Stress Shear Stress (psf) (Psf) Straight C125 Unvegetated 2.25 1.42 158 STABLE Staple D