PN74813 Parachute Rigging Facility - PN 74813 PARACHUTE RIGGING FACILITY - SUPPLEMENT FORMS 04FEB2019

Parachute Rigging Facility
Fort Bragg, Cumberland County, North Carolina
Mason & Hanger Page - a.8 -

APPENDIX H
NCDEQ BIORETENTION CELL SUPPLEMENT FORMS

Discrete SCS Curve Number Method (NCDEQ Stormwater BMP Manual 3.3.2)
Location:Bioretention Area 1 Date:1/7/2019
Soil Group:C
Predevelopment BUA Developed BUA
Area 0.93 acres Area 2.52 acres
Area 40,511 sf Area 109,984 sf
CN*98 CN*98
S 0.20 S 0.20
ia 0.04 in ia 0.04 in
P 1 in P 1 in
Q 0.79 in Q 0.79 in
V 2,670 cf V 7,249 cf
Predevelopment Open Area Developed Open Area
Area 7.92 acres Area 6.33 acres
Area 345,209 sf Area 275,736 sf
CN*76 CN*74
S 3.16 S 3.51
ia 0.63 in ia 0.70 in
P 1 in P 1 in
Q 0.04 in Q 0.02 in
V 1,107 cf V 533 cf
Area 8.85 acres Area 8.85 acres
Total 3,777 cf Total 7,782 cf
Storage Required 4,005 cf
Surface Area 9,200 sf
Riser 9 in
Storage Provided 6,900 cf
Note: Runnoff depth for CN <= 70 set to 0.00 for 1.0" rainfall event based upon
TR55 Urban Hydrology for Small Watersheds Table 2-1
*Composite CN calculated using Army LID Planning and Cost Tool
Developed by USACE Baltimore District and USACE ERDC
Discrete SCS Curve Number Method (NCDEQ Stormwater BMP Manual 3.3.2)
Location:Bioretention Area 2 Date:1/7/2019
Soil Group:B
Predevelopment BUA Developed BUA
Area 0.13 acres Area 0.85 acres
Area 5,663 sf Area 37,026 sf
CN*98 CN*98
S 0.20 S 0.20
ia 0.04 in ia 0.04 in
P 1 in P 1 in
Q 0.79 in Q 0.79 in
V 373 cf V 2,440 cf
Predevelopment Open Area Developed Open Area
Area 2.83 acres Area 2.11 acres
Area 123,275 sf Area 91,912 sf
CN*60 CN*61
S 6.67 S 6.39
ia 1.33 in ia 1.28 in
P 1 in P 1 in
Q 0.00 in Q 0.00 in
V 0 cf V 0 cf
Area 2.96 acres Area 2.96 acres
Total 373 cf Total 2,440 cf
Storage Required 2,067 cf
Surface Area 5,000 sf
Riser 9 in
Storage Provided 3,750 cf
Note: Runnoff depth for CN <= 70 set to 0.00 for 1.0" rainfall event based upon
TR55 Urban Hydrology for Small Watersheds Table 2-1
*Composite CN calculated using Army LID Planning and Cost Tool
Developed by USACE Baltimore District and USACE ERDC
QuantityInfiltration SystemBioretention Cell 2Wet PondStormwater WetlandPermeable PavementSand FilterRainwater HarvestingGreen RoofLevel Spreader-Filter StripDisconnected Impervious SurfaceTreatment SwaleDry PondApplicant:Name and Title:Organization:Street address:City, State, Zip:Phone number(s):Email:DesignerCertification Statement:Signature of DesignerDateEmail:Bldg 3-1333 Butner RdFort Bragg, NC 28310(910) 396-2301Company:Contact:Mailing Address:City, State, Zip:Project Name:AddressCity / TownFort Bragg DPWLee WardSOF Parachute Rigging FacilityFort BraggSUPPLEMENT-EZ FORM COVER PAGESealviolations as well as a report being made to my professional board. - that the information provided in the form is, to the best of my knowledge - that the engineering plans, specifications, operation and maintenancethe information provided here.I am aware that there are significant penalties for submitting falseinformation including the possibility of fines and imprisonment for knowing and belief, true, accurate, and complete; andagreements and other supporting information are consistent with I certify, under penalty of law: that this Supplement-EZ form and all supportinginformation were prepared under my direction or supervision; Designer information for this project:Location(s)Please indicate the types, quantities and locations of SCMs that will be used on this project:[e-mail] number(s):Mike Mayer, Civil EngineerMason & Hanger300 W Vine St Suite 1300Lexington, KY [e-mail] Page13:48 PM 2/4/2019
BIORETENTION CELL1Drainage area number1Total coastal wetlands area (sq ft) sf - Parking / driveway (sq ft)52134 sfTotal surface water area (sq ft) sf - Sidewalk (sq ft)1850 sfTotal drainage area (sq ft)385720 sf - Roof (sq ft)56000 sfBUA associated with existing development (sq ft)40511 sf - Roadway (sq ft) sfProposed new BUA (sq ft)109984 sf - Other, please specify in the comment box below (sq ft) sfPercent BUA of drainage area29%Total BUA (sq ft)109984 sfDesign rainfall depth (in)1.0 inMinimum volume required (cu ft)4005 cfDesign volume of SCM (cu ft)6900 cf#1 Is the SCM sized to treat the SW from all surfaces at build-out?Yes#7 If applicable, with the SCM be cleaned out after construction?Yes#2 Is the SCM located on or near contaminated soils?No#8 Does the mainetenance access comply with General MDC (8)?Yes#3 What are the side slopes of the SCM (H:V)?3:1#9 Does the drainage easement comply with General MDC (9)?Yes#3 Does the SCM have retaining walls, gabion walls or other engineered side slopes? No#10 If the SCM is on a single family lot, does the plat comply with General MDC (10)?Yes#4 Are the inlets, outlets, and receiving stream protected from erosion (10-year storm)? Yes#11 Is there an O&M Agreement that complies with General MDC (11)?Yes#5 Is there a a bypass for flows in excess of the design flow?Yes#12 Is there an O&M Plan that complies with General MDC (12)?Yes#6 What is the method for dewatering the SCM for maintenance?Other#13 Was the SCM designed by an NC licensed professional?Yes#1 SHWT elevation (fmsl)248 ft #6 Percentage of medium to coarse washed sand by volume 85%#1 Bottom of the bioretention cell (fmsl)250 ft #6 Percentage of fines (silt and clay) by volume10%#1 Distance from bottom to SHWT (feet)2 ft #6 Percentage of organic matter by volume 5%#2 Surface area of the bioretention cell (square feet)9200 sf#6 Type of organic materialEngineered Fill#2 Design volume of the bioretention cell (cubic feet)6900 cf#7 Phosphorus Index (P-Index) of media (unitless) 10#2 Ponding depth of the design storm (inches)9 in#8 Will compaction be avoided during construction?Yes#3 Is the bioretention cell used for peak attenuation?No#9 Will cell be maintained to a one inch/hour standard?Yes#3 Depth of peak attenuation over planting surface (in) in #10 Describe the planting plan:#3 Height of peak attenuation outlet above the planting surface (in) in#4 Infiltration rate of the in situ soil (inch/hour).1 in/hr#4 Diameter of the underdrain pipes (if applicable)8 in#4 Does the design include Internal Water Storage (IWS)?Yes #11 Depth of mulch, if applicable (inches) in#4 if so, elevation of the top of the IWS (fmsl)252 ft #11 Type of mulch, if applicablena#4 Elevation of the planting surface (fmsl)256 ft #12 How many clean out pipes are being installed?10#5 Will the cell contain trees and shrubs?No#12 Briefly describe the pretreatment that will be used:#5 Media depth (inches)30 inTHE DRAINAGE AREABIORETENTION CELL MDC FROM 02H .10522.0 feet of open graded aggregate being provided under engineered fill/media depth in order to provide additional storage volume within cell to meet requirements for EISA 438. The engineered fill will infiltrate at approximately 2in/hr (maintained at min 1in/hr), which will eliminate the surface ponded volume within 24 hours, to the storage within the IWS for ultimate infiltration. Additionally, behive grated catch basins are provided as first-line overflow, above required storage volume, but not for peak attenuation volume. Maximum depth of storage of cell to emergency overflow is 12". Emergency overflow weir designed for 100yr storm event. Project based entirely within Fort Bragg (US Gov't property). No easements required. User requires no hardwood mulch due to maintenance issues.Break down of BUA in the drainage area (both new and existing):COMPLIANCE WITH THE APPLICABLE STORMWATER PROGRAMStormwater program(s) that apply (please specify):EISA 438, ARMY LID, FORT BRAGG IDGGENERAL MDC FROM 02H .1050ADDITIONAL INFORMATIONPlease use this space to provide any additional information about this bioretention cell that you think is relevant to the review:Contractor to provide landscape establishment to achieve 100% coverage throughout site in 12 months. Sod is desired by the user for cell. User requires no hardwood mulch within cell.Minimum 3' sod strip. All outlet headwalls to cell have rip-rap outlet protection per NCDEQ requirements.SOF Parachute Rigging FacilityBioretention110:58 AM 2/5/2019
BIORETENTION CELLSOF Parachute Rigging Facility2Drainage area number2Total coastal wetlands area (sq ft) sf - Parking / driveway (sq ft)6356 sfTotal surface water area (sq ft) sf - Sidewalk (sq ft)1250 sfTotal drainage area (sq ft)128938 sf - Roof (sq ft)29420 sfBUA associated with existing development (sq ft)5663 sf - Roadway (sq ft) sfProposed new BUA (sq ft)37026 sf - Other, please specify in the comment box below (sq ft) sfPercent BUA of drainage area29%Total BUA (sq ft)37026 sfDesign rainfall depth (in)1.0 inMinimum volume required (cu ft)2067 cfDesign volume of SCM (cu ft)3750 cf#1 Is the SCM sized to treat the SW from all surfaces at build-out?Yes#7 If applicable, with the SCM be cleaned out after construction?Yes#2 Is the SCM located on or near contaminated soils?No#8 Does the mainetenance access comply with General MDC (8)?Yes#3 What are the side slopes of the SCM (H:V)?3:1#9 Does the drainage easement comply with General MDC (9)?Yes#3 Does the SCM have retaining walls, gabion walls or other engineered side slopes? No#10 If the SCM is on a single family lot, does the plat comply with General MDC (10)?Yes#4 Are the inlets, outlets, and receiving stream protected from erosion (10-year storm)? Yes#11 Is there an O&M Agreement that complies with General MDC (11)?Yes#5 Is there a a bypass for flows in excess of the design flow?Yes#12 Is there an O&M Plan that complies with General MDC (12)?Yes#6 What is the method for dewatering the SCM for maintenance?Other#13 Was the SCM designed by an NC licensed professional?Yes#1 SHWT elevation (fmsl)249 ft #6 Percentage of medium to coarse washed sand by volume 85%#1 Bottom of the bioretention cell (fmsl)254 ft #6 Percentage of fines (silt and clay) by volume10%#1 Distance from bottom to SHWT (feet)5 ft #6 Percentage of organic matter by volume 5%#2 Surface area of the bioretention cell (square feet)5000 sf#6 Type of organic materialEngineered Fill#2 Design volume of the bioretention cell (cubic feet)3750 cf#7 Phosphorus Index (P-Index) of media (unitless) 10#2 Ponding depth of the design storm (inches)9 in#8 Will compaction be avoided during construction?Yes#3 Is the bioretention cell used for peak attenuation?No#9 Will cell be maintained to a one inch/hour standard?Yes#3 Depth of peak attenuation over planting surface (in) in #10 Describe the planting plan:#3 Height of peak attenuation outlet above the planting surface (in) in#4 Infiltration rate of the in situ soil (inch/hour).1 in/hr#4 Diameter of the underdrain pipes (if applicable)8 in#4 Does the design include Internal Water Storage (IWS)?Yes #11 Depth of mulch, if applicable (inches) in#4 if so, elevation of the top of the IWS (fmsl)256 ft #11 Type of mulch, if applicablena#4 Elevation of the planting surface (fmsl)260 ft #12 How many clean out pipes are being installed?5#5 Will the cell contain trees and shrubs?No#12 Briefly describe the pretreatment that will be used:#5 Media depth (inches)30 in2.0 feet of open graded aggregate being provided under engineered fill/media depth in order to provide additional storage volume within cell to meet requirements for EISA 438. The engineered fill will infiltrate at approximately 2in/hr (maintained at min 1in/hr), which will eliminate the surface ponded volume within 24 hours, to the storage within the IWS for ultimate infiltration. Additionally, behive grated catch basins are provided as first-line overflow, above required storage volume, but not for peak attenuation volume. Maximum depth of storage of cell to emergency overflow is 12". Emergency overflow weir designed for 100yr storm event. Project based entirely within Fort Bragg (US Gov't property). No easements required. User requires no hardwood mulch due to maintenance issues.GENERAL MDC FROM 02H .1050Contractor to provide landscape establishment to achieve 100% coverage throughout site in 12 months. Sod is desired by the user for cell. User requires no hardwood mulch within cell.Minimum 3' sod strip. All outlet headwalls to cell have rip-rap outlet protection per NCDEQ requirements.ADDITIONAL INFORMATIONTHE DRAINAGE AREABIORETENTION CELL MDC FROM 02H .1052Break down of BUA in the drainage area (both new and existing):COMPLIANCE WITH THE APPLICABLE STORMWATER PROGRAMStormwater program(s) that apply (please specify):EISA 438, ARMY LID, FORT BRAGG IDGPlease use this space to provide any additional information about this bioretention cell that you think is relevant to the review:Bioretention24:24 PM 2/4/2019
Fort Bragg Parachute Rigging Facility PN74813
Bioretention Cell #1 Underdrain Calculations
1/31/2019
By M. Mayer
Engineered Fill Permeability (K)2 in/hr
Surface Area (A)9200 ft2
Maximum Ponding Depth (C H)3.25 ft
Depth of media (C L)2.5 ft
Flow (Qi)0.55 cfs
Apply 10x Factor of Safety (Q)5.50 cfs
Roughness Factor (n)0.01
Internal Slope (s)0.005
Darcy's Equation
Diameter of Single Pipe (d)15.09 in
Diameter Underdrain Pipes 8 in
Equavalent Number Required 6
Number Underdrain Pipes Provided 10
NCDEQ Stormwater BMP Manual Common BMP Design Elements, July 2007
5.7 Underdrain Systems
Fort Bragg Parachute Rigging Facility PN74813
Bioretention Cell #2 Underdrain Calculations
2/1/2019
By M. Mayer
Engineered Fill Permeability (K)2 in/hr
Surface Area (A)5000 ft2
Maximum Ponding Depth (C H)3.25 ft
Depth of media (C L)2.5 ft
Flow (Qi)0.30 cfs
Apply 10x Factor of Safety (Q)2.99 cfs
Roughness Factor (n)0.01
Internal Slope (s)0.005
Darcy's Equation
Diameter of Single Pipe (d)12.01 in
Diameter Underdrain Pipes 8 in
Equavalent Number Required 3
Number Underdrain Pipes Provided 5
NCDEQ Stormwater BMP Manual Common BMP Design Elements, July 2007
5.7 Underdrain Systems