20072082 Ver 1_Stormwater Plans_20080428

d 7,2_?
TIE JOHN R McADAMS COMPANY, INC.
LETTER OF TRANSMITTAL
To: Annette Lucas
NC Division of Water Qual
401 Oversight & Express Permitting Unit
2331 Crabtree Blvd. Suite 250
Raleiqh, NC 27604
Re: Highway 29 Project (DWQ #07-2082)
Charlotte. NC
Date: April 25, 2008
REGULAR MAIL
Job No.: GWH-06040
I am sending you the following item(s):
COPIES DATE NO. DESCRIPTION
3 4/25/08 Letter & attachments (original & 2 copies)
3 Stormwater Impact Analysis
3 4/18/08 Stormwater M mt Facility Deis n Plans

These are transmitted as checked below:
? As requested ?
® For approval ?
? For review and comment ?
Remarks:
For your use
Copy to:
r•. e? _jq y
APR 2 8 2008
v`A;ER UUAU1`r
..'AIWATEN B(iANUH
Signed:
ennifer Diaz, El
Assoc PE, SW & Environmental
FOR INTERNAL USE ONLY
? Copy Letter of Transmittal Only to File
® Copy Entire Document to File
FN(jINFFRS ¦ PLANNERS ¦ SURVEYORS ¦ ENVIRONMENTAL
RESEARCH TRIANGLEPARK • CIIARLOTT( ¦ WILMINGTON
800-733-5640 ¦ www.liolinrmzardams.com
T
?w +
ff Since 1979
THE JOHN R. McADAMS COMPANY, INC.
April 25, 2008
Ms. Annette Lucas
NC Division of Water Quality
401 Oversight & Express Permitting Unit
2321 Crabtree Boulevard, Suite 250
Raleigh, North Carolina 27604
Re: Stormwater Management Plan
Highway 29 Project (DWQ #07-2082)
GWH-06040
Dear Ms. Lucas:

Presented on behalf of Gateway Homes LLC is the Highway 29 Project
Stormwater Management Plan for your review and approval pursuant to the
NC Division of Water Quality (DWQ) Permit # 07-2082 General Certification
(GC) 3705.
To meet DWQ standards, four wet detention facilities are proposed for the
project. The site has been designed and graded so that all impervious
associated with new development will reach the facilities.
Please find enclosed for your review three copies of the following items:
Research Triangle Park, NC
Post Office Box 14005
Research Triangle Park,
North Carolina 27709
2905 Meridian Parkway
Durham, North Carolina 27713
800-733-5646
919-361-5000
919-361-2269 Fax
Charlotte, NC
6701 Carmel Road
suite 205
Charlotte, North Carolina 28226
800-733-5646
704-527-0800
704-527-2003 Fax
Wilmington, NC
3904 Oleander Drive,
Suite 200
Wilmington, North Carolina 28403
800-733-5646
910-799-8181
910-799-8171 Fax
-Full size Construction Plan drawings including: Drainage Area Maps,
Grading Plan and Detail Sheets
-Wet Detention Basin Supplement forms for each facility
-Operation and Maintenance Agreements (1 original / 2 copies) for each
facility
-Stormwater Management Notebook detailing assumptions and
calculations.
If you have any questions or require any additional information, please do not
hesitate to contact me at [phone].
Sincerely,
THE JOHN R. McADAMS COMPANY, INC.
t`r
nif
er C. 0 z, El
ssociate Project Engineer
Stormwater and Environmental Department
www.johnrmcadams.com i Design Services Focused On Client Success

Permit No.
State of North Carolina
Department of Environment and Natural Resources
Division of Water Quality
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form may be photocopies for use as an original
DWO Stormwater Management Plan Review:
(to be provided by DWQ)
A complete stormwater management plan submittal includes an application form, a wet detention basin
supplement for each basin, design calculations, and plans and specifications showing all basin and outlet
structure details.
1. PROJECT INFORMATION (please complete the following information):
Project Name: Highway 29 Project
Contact Person: James W. Caldwell Phone Number [phone]
For projects with multiple basins, specify which basin this worksheet applies to: Stormwater Wet Pond #1
elevations
Basin Bottom Elevation 584.00 ft.
Permanent Pool Elevation 589.00 ft.
Temporary Pool Elevation 593.50 ft.

areas
Permanent Pool Surface Area 16,930 sq. ft.
Drainage Area 15.11 ac.
Impervious Area 7.87 ac.

volumes
Permanent Pool Volume 49,194 cu. ft.
Temporary Pool Volume 103,202 cu. ft.
Forebay Volume 8,439 cu. ft.

other parameters
SA/DA1 2.11
Diameter of Orifice 2.5 in.
Design Rainfall 1 in.
(floor of the basin)
(elevation of the orifice)
(elevation of the discharge structure overflow)
(water surface area at the orifice elevation)
(on-site and off-site drainage to the basin)
(on-site and off-site drainage to the basin)
(combined volume of main basin and forebay)
(volume detained above the permanent pool)
(approximately 20% of total volume)
(surface area to drainage area ratio from DWQ table)
(2 to S day temporary pool draw-down required)
Design TSS Remova12 85 % (minimum 85% required))
D ,, t
A r FORM SWU-102 Rev 3.99 PAGE 1 OF 4
IORN'deA
1h'ETLANDS Jt?SA?Ct?
Footnotes:
1. When using the Division SA/DA tables, the correct SA/DA ratio for permanent pool sizing should be computed based upon the
actual impervious % and permanent pool depth. Linear interpolation should be employed to determine the correct value for non-
standard table entries.
2. In the 20 coastal counties, the requirement for a vegetative filter may be waived if the wet detention basin is designed to provide
90% TSS removal THE NCDENR BMP manual provides design tables for both 85% TSS removal and 90% TSS removal.
II. REQUIRED ITEMS CHECKLIST
The following checklist outlines design requirements per the Stormwater Best Management Practices Manual
(N.C. Department of Environment, Health and Natural Resources, February, 1999) and Administrative Code
Section: 15 A NCAC 2H .1008.
Initial in the space provided to indicate the following design requirements have been met and supporting
documentation is attached. If the applicant has designated an agent in the Stormwater Management Permit
Application Form, the agent may initial below. If a requirement has not been met, attach justification.
Applicants Initials
JWC a. The permanent pool depth is between 3 and 6 feet (required minimum of 3 feet).
JWC b. The forebay volume is approximately equal to 20% of the basin volume.
JWC c. The temporary pool controls runoff from the design storm event.
JWC d. The temporary pool draws down in 2 to 5 days.
e. If required, a 30-foot vegetative filter is provided at the outlet (include non-erosive flow
N/A calculations).
JWC f. The basin length to width ratio is greater than 3:1.
JWC g. The basin side slopes above the permanent pool are no steeper than 3:1.
N/A h. A submerged and vegetated perimeter shelf with a slope of 6:1 or less (show detail).
JWC i. Vegetative cover above the permanent pool elevation is specified.
JWC j. A trash rack or similar device is provided for both the overflow and orifice.
k. A recorded drainage easement is provided for each basin including access to nearest
JWC right-of-way.
1. If the basin is used for sediment and erosion control during construction, clean out of the
JWC basin is specified prior to use as a wet detention basin.
JWC m. A mechanism is specified which will drain the basin for maintenance or an emergency.
III. WET DETENTION BASIN OPERATION AND MAINTENANCE AGREEMENT
The wet detention basin system is defined as the wet detention basin, pretreatment including forebays and the
vegetated filter if one is provided.
This system (check one)
This system (check one)
? does ® does not incorporate a vegetated filter at the outlet.
? does ® does not incorporate pretreatment other than a forebay.
FORM SWU-102 Rev 3.99 PAGE 2 OF 4
Maintenance activities shall be performed as follows:
1. After every significant runoff producing rainfall event and at least monthly:
a. Inspect the wet detention basin system for sediment accumulation, erosion, trash accumulation,
vegetated cover, and general condition.
b. Check and clear the orifice of any obstructions such that drawdown of the temporary pool occurs
within 2 to 5 days as designed.
2. Repair eroded areas immediately, re-seed as necessary to maintain good vegetative cover, mow vegetative
cover to maintain a maximum height of six inches, and remove trash as needed.
3. Inspect and repair the collection system (i.e. catch basins, piping, swales, riprap, etc.) quarterly to
maintain proper functioning.
4. Remove accumulated sediment from the wet detention basin system semi-annually or when depth is
reduced to 75% of the original design depth (see diagram below). Removed sediment shall be disposed of
in an appropriate manner and shall be handled in a manner that will not adversely impact water quality
(i.e. stockpiling near a wet detention basin or stream, etc.).
The measuring device used to determine the sediment elevation shall be such that it will give an accurate
depth reading and not readily penetrate into accumulated sediments.
When the permanent pool depth reads 3.75
When the permanent pool depth reads 3.75
V
Sediment emoval El. 585.25 75
Bottom evation 584.00 %
------------
feet in the main pond, the sediment shall be removed.
feet in the forebay, the sediment shall be removed.
BASIN DIAGRAM
(fill in the blanks)
Permanent Pool Elevation 589.00
Sediment Removal Elevation 585.25
-----------------------------------
Bottom Elevation 584.00
FOREBAY
MAIN POND
75%
25%
5. Remove cattails and other indigenous wetland plants when they cover 50% of the basin surface. These
plants shall be encouraged to grow along the vegetated shelf and forebay berm.
6. If the basin must be drained for an emergency or to perform maintenance, the flushing of sediment
through the emergency drain shall be minimized to the maximum extent practical.
FORM SWU-102 Rev 3.99 PAGE 3 OF 4
7. All components of the wet detention basin system shall be maintained in good working order.
I acknowledge and agree by my signature below that I am responsible for the performance of the seven
maintenance procedures listed above. I agree to notify DWQ of any problems with the system or prior to any
changes to the system or responsible party.
Print name: 14k. ? 04 "e /Ca ?f' , Z
Title:
Address:
Phone:
Signature
Date:
11121

0
,OT/2
73
Note: The legally responsible party should not be a homeowners association unless more than 50% of the lots have been sold and a
resident of the subdivision has been named the president.
a Notary Publ' for the State of North Carolina
County of )ddo hereby ce •tify that
personally appeared before mday of , 20QQ,f and acknowledge the d e
execution of the forgoing wet detention basin maintenance requirements. Witness my hand and official seal,
I-- zv .
???9ae0e?ap®?
0e ??noncoos ?,,
b_
SEAL
My commission expires

FORM SWU-102 Rev 3.99 PAGE 4 OF 4
Permit No.
State of North Carolina
Department of Environment and Natural Resources
Division of Water Quality
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form may be photocopies for use as an original
DWO Stormwater Management Plan Review:
(to be provided by DWQ)
A complete stormwater management plan submittal includes an application form, a wet detention basin
supplement for each basin, design calculations, and plans and specifications showing all basin and outlet
structure details.
1. PROJECT INFORMATION (please complete the following information):
Project Name: Highway 29 Project
Contact Person: James W. Caldwell Phone Number [phone]
For projects with multiple basins, specify which basin this worksheet applies to: Stormwater Wet Pond #2
elevations
Basin Bottom Elevation 599.00 ft.
Permanent Pool Elevation 604.00 ft.
Temporary Pool Elevation 606.00 ft.

areas
Permanent Pool Surface Area 12,853 sq. ft.
Drainage Area 12.00 ac.
Impervious Area 7.18 ac.

volumes
Permanent Pool Volume 35,996 cu. ft.
Temporary Pool Volume 29,043 cu. ft.
Forebay Volume 9,261 cu. ft.

other parameters
SA/DA1 2.40
Diameter of Orifice 2 in.
Design Rainfall 1 in.
Design TSS Remova12 85 %
(floor of the basin)
(elevation of the orifice)
(elevation of the discharge structure overflow)
(water surface area at the orifice elevation)
(on-site and off-site drainage to the basin)
(on-site and off-site drainage to the basin)
(combined volume of main basin and forebay)
(volume detained above the permanent pool)
(approximately 20% of total volume)
(surface area to drainage area ratio from DWQ table)
(2 to 5 day temporary pool draw-down required)
(minimum 85% required))
FORM SWU-102 Rev 3.99 PAGE 1 OF 4
Footnotes:
1. When using the Division SA/DA tables, the correct SA/DA ratio for permanent pool sizing should be computed based upon the
actual impervious % and permanent pool depth. Linear interpolation should be employed to determine the correct value for non-
standard table entries.
2. In the 20 coastal counties, the requirement for a vegetative filter may be waived if the wet detention basin is designed to provide
90% TSS removal THE NCDENR BMP manual provides design tables for both 85% TSS removal and 90% TSS removal.
II. REQUIRED ITEMS CHECKLIST
The following checklist outlines design requirements per the Stormwater Best Management Practices Manual
(N.C. Department of Environment, Health and Natural Resources, February, 1999) and Administrative Code
Section: 15 A NCAC 2H .1008.
Initial in the space provided to indicate the following design requirements have been met and supporting
documentation is attached. If the applicant has designated an agent in the Stormwater Management Permit
Application Form, the agent may initial below. If a requirement has not been met, attach justification.
Applicants Initials
JWC a. The permanent pool depth is between 3 and 6 feet (required minimum of 3 feet).
JWC b. The forebay volume is approximately equal to 20% of the basin volume.
JWC c. The temporary pool controls runoff from the design storm event.
JWC d. The temporary pool draws down in 2 to 5 days.
e. If required, a 30-foot vegetative filter is provided at the outlet (include non-erosive flow
N/A calculations).
JWC f. The basin length to width ratio is greater than 3:1.
JWC g. The basin side slopes above the permanent pool are no steeper than 3:1.
JWC h. A submerged and vegetated perimeter shelf with a slope of 6:1 or less (show detail).
JWC i. Vegetative cover above the permanent pool elevation is specified.
JWC j. A trash rack or similar device is provided for both the overflow and orifice.
k. A recorded drainage easement is provided for each basin including access to nearest
JWC right-of-way.
1. If the basin is used for sediment and erosion control during construction, clean out of the
JWC basin is specified prior to use as a wet detention basin.
JWC m. A mechanism is specified which will drain the basin for maintenance or an emergency.
III. WET DETENTION BASIN OPERATION AND MAINTENANCE AGREEMENT
The wet detention basin system is defined as the wet detention basin, pretreatment including forebays and the
vegetated filter if one is provided.
This system (check one)
This system (check one)
? does ® does not incorporate a vegetated filter at the outlet.
? does ® does not incorporate pretreatment other than a forebay.
FORM SWU-102 Rev 3.99 PAGE 2 OF 4
Maintenance activities shall be performed as follows:
I . After every significant runoff producing rainfall event and at least monthly:
a. Inspect the wet detention basin system for sediment accumulation, erosion, trash accumulation,
vegetated cover, and general condition.
b. Check and clear the orifice of any obstructions such that drawdown of the temporary pool occurs
within 2 to 5 days as designed.
2. Repair eroded areas immediately, re-seed as necessary to maintain good vegetative cover, mow vegetative
cover to maintain a maximum height of six inches, and remove trash as needed.
3. Inspect and repair the collection system (i.e. catch basins, piping, swales, riprap, etc.) quarterly to
maintain proper functioning.
4. Remove accumulated sediment from the wet detention basin system semi-annually or when depth is
reduced to 75% of the original design depth (see diagram below). Removed sediment shall be disposed of
in an appropriate manner and shall be handled in a manner that will not adversely impact water quality
(i.e. stockpiling near a wet detention basin or stream, etc.).
The measuring device used to determine the sediment elevation shall be such that it will give an accurate
depth reading and not readily penetrate into accumulated sediments.
When the permanent pool depth reads 3.75
When the permanent pool depth reads 3.75
V
Sediment emoval El. 600.25 7
Bottom evation 599.00 ?1
--------------
feet in the main pond, the sediment shall be removed.
feet in the forebay, the sediment shall be removed.
BASIN DIAGRAM
(fill in the blanks)
Permanent Pool Elevation 604.00
Sediment Removal Elevation 600.25
-----------------------------------
Bottom Elevation 599.00
FOREBAY
MAIN POND
75%
25% /
5. Remove cattails and other indigenous wetland plants when they cover 50% of the basin surface. These
plants shall be encouraged to grow along the vegetated shelf and forebay berm.
6. If the basin must be drained for an emergency or to perform maintenance, the flushing of sediment
through the emergency drain shall be minimized to the maximum extent practical.
FORM SWU-102 Rev 3.99 PAGE 3 OF 4
7. All components of the wet detention basin system shall be maintained in good working order.
I acknowledge and agree by my signature below that I am responsible for the performance of the seven
maintenance procedures listed above. I agree to notify DWQ of any problems with the system or prior to any
changes to the system or responsible party.
Print name: 004 U e / Ca 17f'Cni
Title:
Address:
Phone:
Signature
Date:
z X330
Note: The legally responsible party should not be a homeowners association unless more than 50% of the lots have been sold and a
resident of the subdivision has been named the president.
I,
County of -? , dp hereby certify tha
personally appeared before me this Z.3 e/ day of , 20
0,4 d and acknowledge the e
execution of the forgoing wet detention basin maintenance r quirements. Witness my hand and official seal,
?. , a Notary Publi for the State of North Carolina
My commission expires: r7?C,r c4VZ1, .2&U-3
??,9easoae?oveo?a?o
s
.x ?
4 , IA (7t
s
•Y /7111

11121
'3Jr()C`14,o7/e
FORM SWU-102 Rev 3.99 PAGE 4 OF 4
Permit No.
State of North Carolina
Department of Environment and Natural Resources
Division of Water Quality
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form may be photocopies for use as an original
DWO Stormwater Management Plan Review:
(to be provided by DWQ)
A complete stormwater management plan submittal includes an application form, a wet detention basin
supplement for each basin, design calculations, and plans and specifications showing all basin and outlet
structure details.
1. PROJECT INFORMATION (please complete the following information):
Project Name: Highway 29 Project
Contact Person: James W. Caldwell Phone Number [phone]
For projects with multiple basins, specify which basin this worksheet applies to: Stormwater Wet Pond #3
elevations
Basin Bottom Elevation 598.00 ft.
Permanent Pool Elevation 604.00 ft.
Temporary Pool Elevation 606.50 ft.

areas
Permanent Pool Surface Area 7,216 sq. ft.
Drainage Area 2.48 ac.
Impervious Area 1.44 ac.

volumes
Permanent Pool Volume 19,820 cu. ft.
Temporary Pool Volume 21,753 cu. ft.
Forebay Volume 3,590 cu. ft.

other parameters
SA/DAI 2.33
Diameter of Orifice 1 in.
Design Rainfall 1 in.
Design TSS Removal2 85 %
(floor of the basin)
(elevation of the orifice)
(elevation of the discharge structure overflow)
(water surface area at the orifice elevation)
(on-site and off-site drainage to the basin)
(on-site and off-site drainage to the basin)
(combined volume of main basin and forebay)
(volume detained above the permanent pool)
(approximately 20% of total volume)
(surface area to drainage area ratio from DWQ table)
(2 to S day temporary pool draw-down required)
(minimum 85% required)) E
FORM SWU-102 Rev 3.99 PAGE 1 OF 4
Footnotes:
1. When using the Division SA/DA tables, the correct SA/DA ratio for permanent pool sizing should be computed based upon the
actual impervious % and permanent pool depth. Linear interpolation should be employed to determine the correct value for non-
standard table entries.
2. In the 20 coastal counties, the requirement for a vegetative filter may be waived if the wet detention basin is designed to provide
90% TSS removal THE NCDENR BMP manual provides design tables for both 85% TSS removal and 90% TSS removal.
II. REQUIRED ITEMS CHECKLIST
The following checklist outlines design requirements per the Stormwater Best Management Practices Manual
(N.C. Department of Environment, Health and Natural Resources, February, 1999) and Administrative Code
Section: 15 A NCAC 2H .1008.
Initial in the space provided to indicate the following design requirements have been met and supporting
documentation is attached. If the applicant has designated an agent in the Stormwater Management Permit
Application Form, the agent may initial below. If a requirement has not been met, attach justification.
Applicants Initials
JWC a. The permanent pool depth is between 3 and 6 feet (required minimum of 3 feet).
JWC b. The forebay volume is approximately equal to 20% of the basin volume.
JWC c. The temporary pool controls runoff from the design storm event.
JWC d. The temporary pool draws down in 2 to 5 days.
e. If required, a 30-foot vegetative filter is provided at the outlet (include non-erosive flow
N/A calculations).
JWC f. The basin length to width ratio is greater than 3:1.
JWC g. The basin side slopes above the permanent pool are no steeper than 3:1.
JWC h. A submerged and vegetated perimeter shelf with a slope of 6:1 or less (show detail).
JWC i. Vegetative cover above the permanent pool elevation is specified.
JWC j. A trash rack or similar device is provided for both the overflow and orifice.
k. A recorded drainage easement is provided for each basin including access to nearest
JWC right-of-way.
1. If the basin is used for sediment and erosion control during construction, clean out of the
JWC basin is specified prior to use as a wet detention basin.
JWC m. A mechanism is specified which will drain the basin for maintenance or an emergency.
III. WET DETENTION BASIN OPERATION AND MAINTENANCE AGREEMENT
The wet detention basin system is defined as the wet detention basin, pretreatment including forebays and the
vegetated filter if one is provided.
This system (check one)
This system (check one)
? does ® does not incorporate a vegetated filter at the outlet.
? does ® does not incorporate pretreatment other than a forebay.
FORM SWU-102 Rev 3.99 PAGE 2 OF 4
Maintenance activities shall be performed as follows:
1. After every significant runoff producing rainfall event and at least monthly:
a. Inspect the wet detention basin system for sediment accumulation, erosion, trash accumulation,
vegetated cover, and general condition.
b. Check and clear the orifice of any obstructions such that drawdown of the temporary pool occurs
within 2 to 5 days as designed.
2. Repair eroded areas immediately, re-seed as necessary to maintain good vegetative cover, mow vegetative
cover to maintain a maximum height of six inches, and remove trash as needed.
3. Inspect and repair the collection system (i.e. catch basins, piping, swales, riprap, etc.) quarterly to
maintain proper functioning.
4. Remove accumulated sediment from the wet detention basin system semi-annually or when depth is
reduced to 75% of the original design depth (see diagram below). Removed sediment shall be disposed of
in an appropriate manner and shall be handled in a manner that will not adversely impact water quality
(i.e. stockpiling near a wet detention basin or stream, etc.).
The measuring device used to determine the sediment elevation shall be such that it will give an accurate
depth reading and not readily penetrate into accumulated sediments.
When the permanent pool depth reads 4.50
When the permanent pool depth reads 3.75
V
Sediment emoval El. 600.25
Bottom evation 599.00
------------
feet in the main pond, the sediment shall be removed.
feet in the forebay, the sediment shall be removed.
BASIN DIAGRAM
(fill in the blanks)
Permanent Pool Elevation 604.00
Sediment Removal Elevation 599.50
-----------------------------------
Bottom Elevation 598.00
FOREBAY
MAIN POND
75%
25%
5. Remove cattails and other indigenous wetland plants when they cover 50% of the basin surface. These
plants shall be encouraged to grow along the vegetated shelf and forebay berm.
6. If the basin must be drained for an emergency or to perform maintenance, the flushing of sediment
through the emergency drain shall be minimized to the maximum extent practical.
FORM SWU-102 Rev 3.99 PAGE 3 OF 4
7. All components of the wet detention basin system shall be maintained in good working order.
I acknowledge and agree by my signature below that I am responsible for the performance of the seven
maintenance procedures listed above. I agree to notify DWQ of any problems with the system or prior to any
changes to the system or responsible party.
Print name: ?/? ?[J4 U e ?a e)f'Ch,6e/-
f LO
Title:
Address:
Phone:
Signature
Date:

1112
Co,
so

Note: The legally responsible party should not be a homeowners association unless more than 50% of the lots have been sold and a
resid nt of the subdivision has been named the pres' ent.
a Notary Publ' for the State o North Caro 'na
County of , do hereby certify that
personally app red before me this C??l day of , 2090/ and acknowledge the due
execution of the forgoing wet detention basin maintenance requirements. Witness my hand and official seal,
.7
'00
fie, '?, 4i!i6
9
rv'Q m
> ah, ? a
SEAL
My commission expires: Z 7 x/113
FORM SWU-102 Rev 3.99 PAGE 4 OF 4
Permit No.
State of North Carolina
Department of Environment and Natural Resources
Division of Water Quality
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form may be photocopies for use as an original
DWQ Stormwater Management Plan Review:
(to be provided by DWQ)
A complete stormwater management plan submittal includes an application form, a wet detention basin
supplement for each basin, design calculations, and plans and specifications showing all basin and outlet
structure details.
1. PROJECT INFORMATION (please complete the following information):
Project Name: Highway 29 Project
Contact Person: James W. Caldwell Phone Number [phone]
For projects with multiple basins, specify which basin this worksheet applies to: Stormwater Wet Pond #4
elevations
Basin Bottom Elevation 588.00 ft.
Permanent Pool Elevation 594.00 ft.
Temporary Pool Elevation 596.00 ft.

areas
Permanent Pool Surface Area 9,335 sq. ft.
Drainage Area 6.26 ac.
Impervious Area 4.28 ac.

volumes
Permanent Pool Volume 25,492 cu. ft.
Temporary Pool Volume 21,902 cu. ft.
Forebay Volume 4,838 cu. ft.

other parameters
SA/DA1 2.80
Diameter of Orifice 1.5 in.
Design Rainfall 1 in.
(floor of the basin)
(elevation of the orifice)
(elevation of the discharge structure overflow)
(water surface area at the orifice elevation)
(on-site and off-site drainage to the basin)
(on-site and off-site drainage to the basin)
(combined volume of main basin and forebay)
(volume detained above the permanent pool)
(approximately 20% of total volume)
(surface area to drainage area ratio from DWQ table)
(2 to 5 day temporary pool draw-down required)
Design TSS Removal2 85 % (minimum 85% required)) ''
0 ?
FORM SWU-102 Rev 3.99 PAGE 1 OF 4
Footnotes:
1. When using the Division SA/DA tables, the correct SA/DA ratio for permanent pool sizing should be computed based upon the
actual impervious % and permanent pool depth. Linear interpolation should be employed to determine the correct value for non-
standard table entries.
2. In the 20 coastal counties, the requirement for a vegetative filter may be waived if the wet detention basin is designed to provide
90% TSS removal THE NCDENR BMP manual provides design tables for both 85% TSS removal and 90% TSS removal.
II. REQUIRED ITEMS CHECKLIST
The following checklist outlines design requirements per the Stormwater Best Management Practices Manual
(N.C. Department of Environment, Health and Natural Resources, February, 1999) and Administrative Code
Section: 15 A NCAC 2H .1008.
Initial in the space provided to indicate the following design requirements have been met and supporting
documentation is attached. If the applicant has designated an agent in the Stormwater Management Permit
Application Form, the agent may initial below. If a requirement has not been met, attach justification.
Applicants Initials
JWC a. The permanent pool depth is between 3 and 6 feet (required minimum of 3 feet).
JWC b. The forebay volume is approximately equal to 20% of the basin volume.
JWC c. The temporary pool controls runoff from the design storm event.
JWC d. The temporary pool draws down in 2 to 5 days.
e. If required, a 30-foot vegetative filter is provided at the outlet (include non-erosive flow
N/A calculations).
JWC f. The basin length to width ratio is greater than 3:1.
JWC g. The basin side slopes above the permanent pool are no steeper than 3:1.
JWC h. A submerged and vegetated perimeter shelf with a slope of 6:1 or less (show detail).
JWC i. Vegetative cover above the permanent pool elevation is specified.
JWC j. A trash rack or similar device is provided for both the overflow and orifice.
k. A recorded drainage easement is provided for each basin including access to nearest
JWC right-of-way.
1. If the basin is used for sediment and erosion control during construction, clean out of the
JWC basin is specified prior to use as a wet detention basin.
JWC m. A mechanism is specified which will drain the basin for maintenance or an emergency.
III. WET DETENTION BASIN OPERATION AND MAINTENANCE AGREEMENT
The wet detention basin system is defined as the wet detention basin, pretreatment including forebays and the
vegetated filter if one is provided.
This system (check one) ? does ® does not incorporate a vegetated filter at the outlet.
This system (check one) ? does ® does not incorporate pretreatment other than a forebay.
FORM SWU-102 Rev 3.99 PAGE 2 OF 4
Maintenance activities shall be performed as follows:
1. After every significant runoff producing rainfall event and at least monthly:
a. Inspect the wet detention basin system for sediment accumulation, erosion, trash accumulation,
vegetated cover, and general condition.
b. Check and clear the orifice of any obstructions such that drawdown of the temporary pool occurs
within 2 to 5 days as designed.
2. Repair eroded areas immediately, re-seed as necessary to maintain good vegetative cover, mow vegetative
cover to maintain a maximum height of six inches, and remove trash as needed.
3. Inspect and repair the collection system (i.e. catch basins, piping, swales, riprap, etc.) quarterly to
maintain proper functioning.
4. Remove accumulated sediment from the wet detention basin system semi-annually or when depth is
reduced to 75% of the original design depth (see diagram below). Removed sediment shall be disposed of
in an appropriate manner and shall be handled in a manner that will not adversely impact water quality
(i.e. stockpiling near a wet detention basin or stream, etc.).
The measuring device used to determine the sediment elevation shall be such that it will give an accurate
depth reading and not readily penetrate into accumulated sediments.
When the permanent pool depth reads 4.50
When the permanent pool depth reads 3.75
V
Sediment emoval El. 590.25 7
Bottom evation 589.00
--------------
feet in the main pond, the sediment shall be removed.
feet in the forebay, the sediment shall be removed.
BASIN DIAGRAM
(fill in the blanks)
Permanent Pool Elevation 594.00
Sediment Removal Elevation 589.50
------------------------------------
Bottom Elevation 588.00
FOREBAY
MAIN POND
75%
25% /
5. Remove cattails and other indigenous wetland plants when they cover 50% of the basin surface. These
plants shall be encouraged to grow along the vegetated shelf and forebay berm.
6. If the basin must be drained for an emergency or to perform maintenance, the flushing of sediment
through the emergency drain shall be minimized to the maximum extent practical.
FORM SWU-102 Rev 3.99 PAGE 3 OF 4
7. All components of the wet detention basin system shall be maintained in good working order.
I acknowledge and agree by my signature below that I am responsible for the performance of the seven
maintenance procedures listed above. I agree to notify DWQ of any problems with the system or prior to any
changes to the system or responsible party.
Print name: ?/? ,(JA u e 12, e, ICJ 4
Title:
Address: 11121
Ip
Co,
'Xqr /0 ee
Phone: _ ?0 V . r76- 2, 430
Signature
Date: kA 2.-7>
Note: The legally responsible party should not be a homeowners association unless more than 50% of the lots have been sold and a
resident of the subdivision has been named thg president.
I, /'GeWA? 1-,;,7 ,, , a Notary Pub j* for the State North Carolina
County of , do hereby certify that
personally appeared before me this day of - , 200?'? and acknowledge the due
execution of he forgoing wet detention basin maintenance requirements. Witness my hand and official seal,
SEAL
My commission expires: ? ?e??a 2- i 24&
FORM SWU-102 Rev 3.99 PAGE 4 OF 4
I
0

r -
r-?rerr ?,.,

•
•
August 2007
Research Triangle Park, NC
Post Office Box 14005
Research Triangle Park,
North Carolina 27709
2905 Meridian Parkway
Durham, North Carolina 27713
800-733-5646
919-361-5000
919-361-2269 Fax
Charlotte, NC
5311 Seventy-Seven Center Drive,
^+? 66
rth Carolina 28217
uuu o 46
704-527-0800
704-527-2003 Fax
Since 1979
THE JOHN R. McADAMS COMPANY, INC.
HIGHWAY 29
CHARLOTTE, NORTH CAROLINA
STORMWA TER IMPACTANALYSIS
DESIGN OF WET PONDS
GWH-06040
Derick B. Hopkins, El
Associate Project Engineer
Jennifer C. Diaz, El
Associate Project Engineer
James W. Caldwell, PE
Stormwater Project Manager
07-?V Cl/
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08
NDS

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A?
•
Comprehensive Land Development Design Services
www.johnrmcadams.com We help our clients succeed.
Highway 29
• MASTER PLAN- Stormwater Impact Analysis and Wet Pond Design
Proiect Description
Located approximately in the north east corner of the intersection of Highway 29
and Pavilion Boulevard in Mecklenburg County, North Carolina is the proposed
development known as Highway 29. The development is approximately 49.81 acres.
The proposed development will consist of multi-family and commercial development
along with all associated infrastructure (i.e. roads, driveways, water, sewer). The project
is proposed to be constructed in two phases.
The site will be subject to City of Charlotte, and North Carolina Department of
Environment and Natural Resources (NCDENR), Department of Water Quality (DWQ)
regulations. The City of Charlotte will require that reduction in the peak flow rates
generated by the site be no greater than the pre-development flow rates in the 2-, and 10-
year storm events. The City of Charlotte, as part of the rezoning petition, for the small
2.94 acre commercial tract on the southwest side of the tract, will require that the 1-year,
24-hour volume difference in run-off, from the commercial tract, be treated for water
quality. The NCDENR Department of Water Quality will require that all impervious
surfaces of the site be treated for 85% Total Suspended Solid (TSS) removal.
To accomplish all design criteria, four wet ponds are proposed. The wet ponds
are sized in accordance to NCDENR "Stormwater Best Management Practices" (April
99) to achieve a TSS removal efficiency of 85%. This project has received a 401 permit
from the North Carolina Division of Water Quality (NCDWQ). A requirement of this
permit is a Stormwater Management Plan which treats the site for 85% TSS removal.
NCDWQ will review this Stormwater Management Plan in conjunction with the City of
Charlotte. Where necessary the ponds were enlarged to create enough above normal pool
storage to satisfy the City of Charlotte detention requirements while maintaining the
necessary surface area and average depth to assure the NCDWQ requirements are met.
Per City of Charlotte requirements, the detention modeling for this project only
accounts for onsite areas. Therefore the pre-development and post-development
0 subbasins account for the onsite areas that drain to the project boundaries and the offsite
areas that drain directly into the ponds in the post-development condition. The offsite
• areas that flow into and through the site in the stream are not accounted for in the
detention study. This methodology provides a design to detain onsite flows as a result of
the proposed development only and may not necessarily provide an accurate model of
actual pre-development to post-development conditions as runoff leaves the south
property line under Highway 29.
The pre-development model consists of two drainage basins. These drainage
basins are bound by topography onsite and the site boundary. The point of analysis for
this project in located at the south eastern side of the project where the large central
stream feature crosses the property boundary under Highway 29. The pre-development
cover condition, from aerial photo, is 100% wooded. This will ensure a conservative pre-
development flow rate, and volume. Soil Conservation Service TR-55 method is used to
calculate the Time of Concentration ("Tc") for each subbasin.
The post-development model consists of two drainage basins. Most of Subbasin
2 has been re-directed toward Pond #1 to treat for 85% TSS as well as the 1-year, 24-hour
volume difference. A small portion of Subbasin 2 in the post-development condition
bypasses and does not flow into the pond. The result of redirecting the flow from
Subbasin 2 to Pond #1 effectively increases the contributing area to Subbasin 1 and
ultimately the culvert underneath Highway 29. Therefore, a diversion analysis was
performed as part of this study to assure that the increase in area did not affect the
presumed designed flow of the culvert.
Each pond in the post-development condition has its own drainage area that
consists of the onsite area that drains into the pond as well as the offsite area that drains
directly into each pond. The same reach as in the pre-development model, as well as
Point of Analysis are used. Cover conditions in the post-development model were taken
to be either impervious or open areas. No wooded area is assumed, despite the fact that
some areas (i.e. SWIM buffers) will not be disturbed or developed. This is done to attain
a conservative design. All "Tc" paths are assumed to be 5 minutes in the post-
development. This is, once again, is done to attain a conservative design.
0
Calculation Methodology
• Rainfall Data is taken from NOAA Atlas 14. Two sets of precipitation data are
used based on guidance form NOAA. The first set of data is the statistically
derived partial duration set. It is recommended that this data be used for storms
events smaller than the 20 to 25 year storms. The second set of data is the
statically derived annual maxima set. This set of data is recommended for all
storms greater than the 20 to 25 year storms. All storms are modeled as
frequency type storms.
• Soil Data is from the NRCS web soil survey. Soil types for each subbasin are
calculated and composite curve number created from this data. The site is
completely composed of "HSG C" soils.
• A composite SCS curve number was calculated for the pre-development
condition and the proposed post-development drainage area based on cover
conditions and existing soils.
• HEC-HMS Version 3.1.0, by the U.S. Army Corp of Engineers, is used to
• produce the pre-development and post-development runoff hydrographs, as
well as the routing calculations for the proposed detention facilities. The stage-
storage, and storage-discharge curves are developed outside of HMS and
imported.
• Time of Concentration is calculated based on the SCS (MRCS) TR-55
methodology. In the pre-development all overland flow occurs in 100'. In the
post-development condition all developed areas are assumed to have times of
concentration of 5 minutes.
• Reach times are calculated based on a stream flow velocity of approximately 5
fps. This velocity is chosen based on the fact that velocities greater than 5 fps
would be excessively erosive and unrealistic and those velocities slower than 5
fps second would result in streams with a "slack" water condition which is also
considered unrealistic.
• Spillways for all the detention facilities are modeled in Haestad Methods
PondPack Version 8.0. The rating curve developed by PondPack is imported to
• HEC-HMS for routing.
• A 100-year water surface elevation was calculated using HEC-RAS for the
accompanying 100+1 study. This water surface elevation was used as a tail
water condition for the 100-year routing of the ponds to ensure that each pond
could safely pass the 100-year event.
Diversion Analysis
In order to satisfy City of Charlotte and NCDWQ requirements, a portion of site
was redirected to flow to a proposed pond for detention and treatment. This diversion
effectively reduces the contributing area of Subbasin 2 and increases the contributing area
of Subbasin 1 and ultimately the contributing area to the Highway 29 culvert located at
the southeast corner of the project. This existing NCDOT culvert was most likely
designed for the 50-year storm based on the projected build-out of the watershed. The
watershed for this culvert includes 262.64 acres in addition to the project site. The
project site contributes 42.50 acres in the pre-diversion condition; post-diversion
increases the contributing area to 48.63 acres. The flows associated with the increased
• watershed area must be less than the design flows of the existing culvert to assure that the
proposed development is not worsening conditions at the Highway 29 crossing.
The calculation methodology for flow rates used in this diversion analysis
remains the same as discussed above with the exception of the SCS curve number
calculation. The curve number for the pre-diversion condition was calculated from
zoning conditions as an estimate for the projected build-out of the watershed. The post-
diversion condition used zoning conditions for all offsite contributing area and proposed
cover conditions for the onsite area. These calculations and results are provided in detail
in the supporting information of this report.
Discussion of Results and Conclusion
The proposed stormwater management facility plan succeeds in meeting the
design criteria per the City of Charlotte, and NCDENR DWQ. Also, the results of the
diversion analysis indicate no adverse affects to the downstream culvert. Please see the
summary or results page for detailed information concerning flow rates.
0
If the development is built as proposed within this report, all applicable design
• criteria will be met. However, modifications to the proposed development that change
assumptions made in this report will invalidate this report. Some modification may
include, but are not limited to:
1. Changes in the amount of proposed site impervious surface area.
2. Changes in proposed grading, to affect drainage breaks presented in post-
development.
•
0
Highway 29
GWH-06040
Subbasin #1
Event
2-Year
10-Year

Subbasin #2
Event
2-Year
10-Year

Wet Pond #1
Summary of Results
;lopment [cfs] Post-Develops
43.3 37.3
88.0 87.1
lopment [cfs] Post-Development [cfs
8.0 2.0
16.1 3.1
Normal Water Surface Elevation [ft] = 589.00
To of Dam [ft] = 596.00
100-Year WSE [ft] = 594.79
100-Year Freeboard [ft] = 1.21
Wet Pond #2
Normal Water Surface Elevation [ft] = 604.00
To of Dam ft] = 610.50
100-Year WSE [ft] = 609.59
100-Year Freeboard [ft] = 0.91
Wet Pond #3
0
•
Normal Water Surface Elevation [ft] = 604.00
To of Dam [ft] = 608.00
100-Year WSE [ft] = 606.92
100-Year Freeboard [ft] = 1.08
Wet Pond #4
Normal Water Surface Elevation [ft] = 594.00
To of Dam ft = 598.00
100-Year WSE [ft] = 596.80
100-Year Freeboard [ft] = 1.20
mge [cfs
-14%0
-1%
urge [cfs
-75%
-81%
* Note: All detention facilities are in Subbasin #1. There is no detention in Subbasin #2.
Diversion Analysis
Event Pre-Diversion [cfs] Post-Diversion [cfs] Change [cfs]
50-vear 794_R 779 R
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Summary of Results
J.C. Diaz, El
4/4/2008
Page 1
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RAINFALL DATA
2 BACKGROUND INFORMATION

3 PRE-DEVELOPMENT
HYDROLOGIC CALCULATIONS

4 POST-DEVELOPMENT
HYDROLOGIC CALCULATIONS
5 WET POND #1 DESIGN
6 WET POND #2 DESIGN
7 WET POND #3 DESIGN
8 WET POND #4 DESIGN
9 DIVERSION ANALYSIS
•
Rainfall Data

Contents
•
Partial Duration Rainfall Data
Annual Maxima Rainfall Data
Highway 29
GWH-06040
Precipitation Frequency Data Server
` POINT PRECIPITATION
FREQUENCY ESTIMATES
FROM NOAA ATLAS 14V110
North Carolina 35.33 N 80.71 W 597 feet
from "Precipitation-Frequency Atlas of the United States" NOAA Atlas 14, Volume 2, Version 3
G.M. Bonnin, D. Martin, B. Lin, T. Parzybok, M.Yekta, and D. Riley
NOAA, National Weather Service, Silver Spring, Maryland, 2004
Extracted: Thu Jul 12 2007
•
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Page 1 of 5
http://hdse.nws.noaa.gov/cgi-binlhdsclbuildout.perl?type=pf&series=pd&units=us&statena... 7/12/2007
Text version of table These precipitation frequency estimates are based on a partial duration series. ARI is the Average Recurrence Interval.
Please refer to the documentation for more information. NOTE: Formatting forces estimates near zero to appear as zero.
Precipitation Frequency Data Server
Partial duration based Point Precipitation Frequency Estimates Version: 3
35.33 N 80.71 W 597 ft
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1 2 3 4 5 6 7 8 910 20 30 40 50 80 100 140 200 300 500 700 1000
Average Recurrence Interval <years)
Duration
5-min [s ?• - 48-hr x 30-day x
10-min 0 3-hr -w 4-day -d-
15-min 0 6-hr, - 7-day -e- 60-day -A
30-min -a 12-hr ?-- 10-day -+-
60-min -+?- 24-hr --e-- 20-day -a-
http://hdse.nws.noaa.gov/cgi-binlhdsc/buildout.perl?type=pf&series=pd&units=us&statena... 7/12/2007
Precipitation Frequency Data Server
Partial duration based Point Precipitation Frequency Estimates Version: 3
35.33 N 80.71 W 597 ft
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C C C C C C E L L L L L L L L L ]1 ON s T T a s a a n
••a ••? •? .•+ •? •.? I L S S s C S S M M M M M M M M M M
E 8 E E E E? I 1 I I I I I I I ??? 'a ? ?? ? ??
I I I I I I N M V' ?D OD N M V' ?0 W I I I I 1 1 1 I I I
Iii M In M M I9 ,•. .? .? N M a CO V• In N m 110 m M n m
- - Cl) w m Duration -+ - N M V W
Thu Jul 12 13:49:29 2007
Average Recurrence Interval
(years)
I ME
2-0 100-
5 -+- 200 -e-
10 ?- 500 ?-
25 - 1000 -a -
Confidence Limits -
* Upper bound of the 90% confidence interval
Precipitation Frequencv Estimates (inches) 1?
AU** 5 10 15 30 60 120 3 6 12 24 F44 7 10 20 30 45 60
(years) min min min hr hr hr hr day day day 11 11 I
day day day day
0.43 0.69 0.86 1.19 1.48 1.72 1.85 2.24 2.65 3.07 3.59 4.01 4.61 5.27 7.02 8.60 10.77 12.79
0 0.51 0.82 1.03 1.42 1.79 2.09 2.23 2.70 3.21 3.71 4.33 4.82 5.576F6 27 8.28 10.11 12.59 14.90
1.21 1.72 2.20 2.59 2.79 3.37 4.01 4.66 5.39 5.94 6.69 7.54 9.77 11.76 14.38 16.82
0 0.60 F951 -
F 16 5-66150 5 1.33 1.92 2.50 2.97 3.21 3.89 4.65 5.40 6.23 6.83 7.64 8.53 10.95 13.03 15.76 1852
25 0.72 1.15 1.46 2.16 2.88 3.46 3.78 4.59 5.52 6.40 7.36 8.05 8.95 9.87 12.54 14.71 17.55 20.26
50 0.77 1.23 1.55 2.34 3.17 3.83 4.23 5.15 6.21 7.20 8.27 9.03 9.99 10.93 13.79 16.01 18.92 21.73
100 0.81 1.29 1.64 2.50 3.45 4.21 4.68 5.72 6.93 8.03 9.19 10.03 11.07 12.00 15.05 17.30 20.26 23.13
200 0.85 1.35 1.71 2.66 3.73 4.59 5.15 6.31 7.69 8.88 10.14 11.05 12.18 13.09 16.33 18.61 21.58 24.52
500 0.90 1.42 1.79 2.85 4.08 5.08 5.80 7.13 8.74 10.06 11.46 12.47 13.72 14.58 18.08 20.34 23.30 26.32
1000 0.93 1.47 1.84 2.98 4.35 5.46 6.32 7.78 9.60 11.00 12.51 13.59 14.93 15.75 19.45 21.69 24.61 27.70
'The upper bound of the confidence interval at 90% confidence level is the value which 5% of the simulated quantile values for a given frequency are greater than
I nese preclpltauon frequency esumates are oaseo on a partial ourahon series. ARI is the Average Recurrence Interval.
Please refer to the documentation for more information. NOTE: Formatting prevents estimates near zero to appear as zero.
* Lower bound of the 90% confidence interval
http://hdsc.nws.noaa.gov/cgi-binlhdsclbuildout.perl?type=pf&series=pd&units=us&statena... 7/12/2007
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Precipitation Frequency Data Server
Estimates
Page 4 of 5
10** 5 10 15 30 60 120 F3 6 12 24 4
7 10 2
F 1 IF1 ]
0 30 45 60
(years) min min min min mimin hr hr hr hr hr ay day day day day day
8 WF-1
0.37 0.59 0.73 1.01 1.26 1.45 1.55 1.88 2.24 2.65 3.11 3.50 4.06 4.66 6.29 7.75 9.82 11.75
0 0.43 0.69 0.87 1.21 1.51 1.75 1.87 2.27 2.70 3.20 3.75 4.20 4.84 5.5317 42 9.12 11.49 13.69
0 0.51 0.81 1.02 1.46 1.86 2.17 2.33 2.83 3.38 4.02 4.67 5.17 5.89 6.64 8.75 10.59 13.11 15.45
10 0.56 0.89 1.12 1.63 2.12 2.48 2.68 3.26 3.90 4.65 5.38 5.93 6.71 7.51 9.80 11.73 14.36 16.81
25 0.61 0.97 1.23 1.83 2.43 2.89 3.14 3.83 4.61 5.50 6.35 6.97 7.84 8.66 11.19 13.22 15.96 18.56
50 0.65 1.03 1.31 1.97 2.67 3.18 3.50 4.27 5.16 6.19 7.11 7.79 8.73 9.56 12.28 14.35 17.17 19.86
100 0.68 1.08 1.37 2.09 2.88 3.47 3.85 4.71 5.72 6.88 7.88 8.63 9.64 10.48 13.36 15.46 18.33 21.10
200 0.71 1.12 1.42 2.20 3.09 3.74 4.19 5.14 6.27 7.58 8.67 9.48 10.57 11.39 14.44 16.57 19.47 22.30
500 0.73 1.16 1.46 2.33 3.34 4.09 4.64 5.72 7.02 8.53 9.74 10.65 11.82 12.63 15.91 18.03 20.94 23.86
1000 0.75 1.19 1.49 2.41 3.52 4.34 4.98 6.15 7.59 9.28 10.57 11.55 12.81 13.59 17.05 19.14 22.04 25.03
`The lower bound of the confidence interval at 90% confidence level is the value which 5% of the simulated quantile values for a given frequency are less than.
" These precipitation frequency estimates are based on a partial duration maxima series. ARI is the Average Recurrence Interval.
Please refer to the documentation for more information. NOTE: Formatting prevents estimates near zero to appear as zero.
Maps -
These maps were produced using a direct map request from the
U.S. Census Bureau Mapping and Cartographic Resources
Tiger Map Server.
Please read disclaimer for more information.
http://hdsc.nws.noaa. gov/cgi-binjhdsclbuildout.perl?type=pf&series=pd&units=us&statena... 7/12/2007
Precipitation Frequency Data Server
•
Other Maps/Photographs -
LEGEND
Page 5 of 5
- State - Connector
- County 1 Stream
E7 Indian Resv Military Area
Lake/Pond/Ocean '-A National Park
- Street -J Other Park
-- Expressway [=1 C i ty
-Highway
0 -9unty
6
i
Scale 1:220503
ip p
*aUerae--true scale depends I
'
?8mi
4 6 8 4 km
on monitor resolution
View USGS digital orthophoto quadrangle D(_OQ) covering this location from TerraServer; USGS Aerial Photograph
may also be available
from this site. A DOQ is a computer-generated image of an aerial photograph in which image displacement caused by terrain
relief and camera tilts has been removed. It combines the image characteristics of a photograph with the geometric qualities
of a map. Visit the USGS for more information.
0 Watershed/Stream Flow Information -
Find the Watershed for this location using the U.S. Environmental Protection Agency's site.
Climate Data Sources -
Precipitation frequency results are based on data from a variety of sources, but largely NCDC. The following links provide
general information
about observing sites in the area, regardless of if their data was used in this study. For detailed information about the
stations used in this study,
please refer to our documentation.
Using the National Climatic Data Center's (NCDC station search engine, locate other climate stations within:
+/-30 minutes OR +/-1 degree of this location (35.33/-80.71). Digital ASCII data can be obtained
directly from NCDC.
Hydrometeorological Design Studies Center
DOC/NOAA/National Weather Service
1325 East-West Highway
Silver Spring, MD 20910
[phone]
Questions?: HDSC.Ouestions a,noaa.eov
•
Disclaimer
http://`hdsc.nws.noaa. gov/cgi-binlhdsclbuildout.perl?type=pf&series=pd&units=us&statena... 7/12/2007
Ro.H-w 80.7-W AO-A"w
Precipitation Frequency Data Server
POINT PRECIPITATION A -
FREQUENCY ESTIMATES al `?? ?
FROM NOAA ATLAS 14 M???
North Carolina 35.33 N 80.71 W 597 feet
from "Precipitation-Frequency Atlas of the United States" NOAA Atlas 14, Volume 2, Version 3
G.M. Bonnin, D. Martin, B. Lin, T. Parzybok, M.Yekta, and D. Riley
NOAA, National Weather Service, Silver Spring, Maryland, 2004
Extracted: Thu Jul 12 2007
Confidence Limits Seasonality Location Maps Other info
Estimates (inches
Page 1 of 5
GIS data 11 Maps 11 Help 11 D
P* 5 10 15 30 60 120 3 6 12 24 48 4 7 10 20 30 45 60
(1-in- min min min min min min hr hr hr hr hr day day day day day day day
Y)
0.43 0.70 0.87 1.21 1.51 1.76 1.88 2.27 2.70 3.17 3.71 4.14 4.75 5.42 7.22 8.85 11.08 13.16
0.54 0.86 1.09 1.55 1.98 2.32 2.49 3.01 3.59 4.22 4.90 5.43 6.14 6.92 9.05 10.92 13.43 15.77
10 0.60 0.96 1.21 1.76 2.29 2.70 2.91 3.53 4.22 4.96 5.74 6.32 7.10 7.94 10.27 12.26 14.92 17.40
F- I 25 0.67 1.06 1.35 1.99 2.65 3.16 3.45 4.20 5.06 5.92 6.83 7.49 8.36 9.24 11.83 13.92 16.70 19.35
50 0.71 1.13 1.43 2.15 2.92 3.51 3.86 4.71 5.71 6.67 l -1
7.67 8.40 9.34 10.22 13.00 15.15 18.00 20.73
100 0.75 1.19 1.50 2.30 3.17 3.85 4.28 5.24 6.38 7.43 8.52 9.32 10.34 11.22 14.18 16.35 19.26 22.06
200 0.78 1.24 1.57 2.44 3.42 4.18 4.70 5.78 7.08 8.22 9.40 10.27 11.36 12.24 15.38 17.56 20.48 23.36
500 0.82 1.30 1.64 2.61 3.74 4.62 5.28 6.52 8.05 9.30 10.61 11.58 12.77 13.61 17.00 19.17 22.09 25.06
1000 0.85 1.34 1.68 2.72 3.98 4.96 5.74 7.10 8.82 10.15 11.56 12.60 13.89 14.69 18.26 20.41 23.31 26.33
- - - - -- - - -- --
Text version of table ' These precipitation frequency estimates are based on an annual maxima series. AEP is the Annual Exceedance Probability.
Please refer to the documentation for more information. NOTE: Formatting forces estimates near zero to appear as zero.
101 1 •

http:llhdsc.nws.noaa.gov/cgi-binlhdsclbuildout.perl?type=pf&series=am&units=us&staten... 7/12/2007
•
•
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Precipitation Frequency Data Server
Annual Maxima based Point Precipitation Frequency Estimates Version: 3
35.33 N 80.71 W 597 ft
Page 2 of 5
2 3 4 5 6 7 8 910 20 30 40 50 80 100 140 200 300 500 700 1000
Annual Exceedance Probability 41-in-Y?
Thu Jul 12 13:51:19 2007
27
26
25
24
23
22
21
20
19
18
4? 17
16
a 15
14
0 13
12
iM
1 1
Q 10
9
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Duration
5-min - 48-hr
30-day-
10-min -e- 3-hr -w- 4-day -?- -V5_«r,,; ,-
15-min + 6,-hr -a- 7-da -e -
y 60-day -?-
30-min -a 12-hr + 10-day +
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http://hdsc.nws.noaa.gov/cgi-binlhdsc/buildout.perl?type=pf&series=am&units=us&staten... 7/12/2007
Precipitation Frequency Data Server
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Annual Exceedance Probability
(1-in-Y)
i in 2 -s 1 in 100 -
I in 5 + 1 in 200 -+s-
1 in 10 -a- 1 in 500 +
1 to 25 -x 1 in 1000 -e -
Confidence Limits -
Annual Maxima based Point Precipitation Frequency Estimates Version: 3
35.33 N 80.71 W 597 ft
Page 3 of 5
£ £ £ £ £
." £ E L L L L L L L L L T T T T T :P T 31 71 T
."' .? .•+ +
E E E •E •.+ I t t Z Z S S t s £ N N N M N N N
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Thu Jul 12 13:51:19 2007
27
26
25
24
23
22
21
.. 20
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s 18
a 17
m 16
? 15
£ 14
0 13
++ 12
M 11
10
9
U 8
7
L 6
5
4
3
2
1
0
* Upper bound of the 90% confidence interval
Precipitation Frequencv Estimates (inches) 11
1-1n- 5 10 1115 1130 1160 111201 3 6 12 11 24 11 48 4 Ld ]1 11 11 1
10 20 30 45 60
min min 11 min min min min hr hr hr hr hr day day day 11 day day day
0.47 0.76 0.95 1.31 1.65 1.93 2.06 2.49 2.95 3.42 3.99 4.44 5.06 5.77 7.62 9.31 11.59 13.72
I 10.58 0.93 1.18 1.68 2.15 2.54 2.73 3.30 3.92 4.55 5.27 5.81 6.54 7.37 9.55 11.50 14.05 16.45
F -7 10 0.65 1.04 1.31 1.90 2.48 2.94 3.18 3.85 4.61 5.34 6.17 6.76 7.56 8.45 10.84 i-2 90 15.60 18.14
25 0.72 1.15 1.46 2.16 2.87 3.45 3.76 4.57 5.50 6.38 7.33 8.02 8.91 9.83 12.49 14.65 17.48 20.18
50 0.77 1.22 1.55 2.33 3.16 3.82 4.21 5.13 6.19 7.17 8.23 8.99 9.95 10.88 13.73 15.95 18.85 21.64
100 0.81 1.29 1.63 2.49 3.44 4.19 4.66 5.70 6.91 7.99 9.15 9.98 11.02 11.95 14.99 17.24 20.18 23.04
200 0.85 1.35 1.70 2.65 3.71 4.57 5.13 6.29 7.66 8.84 10.10 11.00 12.13 13.04 16.26 18.53 21.49 24.42
500 0.90 1.42 1.78 2.84 4.07 5.06 5.78 F71-0]F8 70 10.02 11.42 12.42 13.66 14.52 18.00 20.26 23.21 26.22
1000 0.93 1.46 1.83 2.97 4.33 5.44 6.29 7.75 9.56 10.96 12.46 13.54 14.87 15.69 19.37 21.61 24.51 27.58
'The upper bound of the confidence interval at 90% confidence level is the value which 5% of the simulated nuantile values fnr a nivpn frPni iPnrv nrp nrpafar than
_ i nese precipltanon frequency estimates are based on an annual maxima series. AEP is the Annual Exceedance Probability.
Please refer to the documentation for more information. NOTE: Formatting prevents estimates near zero to appear as zero.
•
* Lower bound of the 90% confidence interval
http://hdsc.nws.noaa. gov/cgi-binlhdsc/buildout.perl?type=pf&series=am&units=us&staten... 7/12/2007
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Page 4 of 5
are less than.
These maps were produced using a direct map request from the
U.S. Census Bureau Mapping and Cartographic Resources
Tiger Map Server.
Please read disclaimer for more information.
LEGEND
•
Precipitation Frequency Data Server
Maps -
- State
- County
Indian Resv
Lake/Pond/Ocean
- Street
-- Expressway
- Highway .0
- Connector
Stream
Military Area
..,Hat i ona I Park
Other Park
C] City
f- Clunty.6 .8 mi
Scale 1:228583 Z
*avera?e--true scale depends on monitor $ esoiution
http://`hdsc.nws.noaa. gov/cgi-binlhdsclbuildout.perl?type=pf&series=am&units=us&staten... 7/12/2007
"These precipitation frequency estimates are based on an annual maxima series. AEP is the Annual Exceedance Probability.
Please refer to the documentation for more information. NOTE: Formatting prevents estimates near zero to appear as zero.
Precipitation Frequency Data Server
•
Other Maps/Photographs -
Page 5 of 5
View USGS digital orthophoto quadrangle (D?2) covering this location from TerraServer; USGS Aerial Photograph
may also be available
from this site. A DOQ is a computer-generated image of an aerial photograph in which image displacement caused by terrain
relief and camera tilts has been removed. It combines the image characteristics of a photograph with the geometric qualities
of a map. Visit the USGS for more information.
• Watershed/Stream Flow Information -
Find the Watershed for this location using the U.S. Environmental Protection Agency's site.
Climate Data Sources -
Precipitation frequency results are based on data from a variety of sources, but largely NCDC. The following links provide
general information
about observing sites in the area, regardless of if their data was used in this study. For detailed information about the
stations used in this study,
please refer to our documentation.
Using the National Climatic Data Center's (NCDC) station search engine, locate other climate stations within:
+/-30 minutes OR +/-1 degree of this location (35.33/-80.71). Digital ASCII data can be obtained
directly from NCDC.
Hydrometeorological Design Studies Center
DOC/NOAA/National Weather Service
1325 East-West Highway
Silver Spring, MD 20910
[phone]
Questions?: [e-mail]
Disclaimer
•
http://hdsc.nws.noaa.gov/cgi-binlhdsclbuildout.perl?type=pf&series=am&units=us&staten... 7/12/2007
so_s"w A0.7'"W Ao_rl"w
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Background Information
0
Contents
Aerial Photograph
U.S.G.S. Quadrangle
Site Soils Map
Soils Curve Number Calculations
Highway 29
GWH-06040
Michael F. Easley, Governor
William G. Ross Jr., Secretary
North Carolina Department of Environment and Natural Resources
Coleen H. Sullins, Director
Division of Water Quality
January 31, 2008
DWQ# 07-2082
Mecklenburg County
Mr. Dave Ransenberg
11121 Carmel Commons Blvd., Ste. 350
Charlotte, NC 28226
Subject: Hwy 29 Project
APPROVAL of 401 Water Quality Certification with Additional Conditions
Dear Mr. Ransenberg:
FEB - ,+ "'08
Q W- o(OC 4o
G•6Uc.hhol. G
& - r\A u o- re,, 1,'. ce
You have our approval, in accordance with the attached conditions and those listed below, to impact
288 linear feet (If} of unnamed stream to Mallard Creek in order to develop the site in Mecklenburg County, as
described in your application received by the Division of Water Quality (DWQ) on December 14, 2007. After
reviewing your application, we have determined that this project is covered by Water Quality General
Certification Number 3705, which can be viewed on our web site at http://h2o.enr.state.nc.us/ncwetlands. The
General Certification allows you to use Nationwide Permit Number 29 once it is issued to you by the U.S. Army
Corps of Engineers. Please note that you should get any other federal, state or local permits before
proceeding with your project, including those required by (but not limited to) Sediment and Erosion Control,
Non-Discharge, and Water Supply Watershed regulations.
The above noted Certification will expire when the associated 404 permit expires unless otherwise
specified in the General Certification. This approval is only valid for the purpose and design that you described
in your application. If you change your project, you must notify ins in writing, and you may be required to send
us a new application for a new certification. If the property is sold, the new owner must be given a copy of the
Certification and approval letter; and is thereby responsible for complying with all conditions.
In addition to the requirements of the certification, you must also comply with the following conditions:
1. The Mooresville Regional Office shall be notified in writing once construction at the approved impact areas
has commenced.
2. Culverts placed in streams/wetlands shall be installed "in the dry". Immediately upon completion of the
installation, water flow shall be returned to its natural course. Existing stream dimensions (including the
cross section dimensions, pattern, and longitudinal profile) must be maintained (or restored via constructed
benches) above and below locations of each culvert. If any of the existing pipes are or become perched,
the appropriate stream grade shall be re-established or, if the pipes installed in a perched manner, the
pipes shall be removed and re-installed correctly.
3. Mitigation must be provided for the proposed impacts as specified in the table below. We understand that
you wish to make a payment to the NC Ecosystem Enhancement Program (EEP) to meet this mitigation
requirement. This has been determined by the DWQ to be a suitable method to meet the mitigation
requirement. Until the EEP receives and clears your check (made payable to: DENR - Ecosystem
Enhancement Program Office), no impacts specified in this Authorization Certificate shall occur. The EEP
should be contacted at [phone] if you have any questions concerning payment into a restoration
fund. N,opnn?ICaroJJ na
,NAz'lflYfl?(J
?rth Carolina Division or water Qttaiity 610 East Center Ave., Suite 301 Mooresville, NC 28115 Phone [phone] Customer Service
Internet ncuratetqulaity.org FAX [phone]
An Equal Opportunity/Affirmative Action Employe(- 50% Recycled/10% Post Consumer Paper
You have 60 days from the date of this approval to make this payment. For accounting purposes, this
Authorization Certificate authorizes payment to the EEP to meet the following compensatory mitigation
requirement:
Compensatory Mitigation
Required River and Sub-basin
Nil rhBer
Stream 288 feet Yadkin 3040905
Wetlands acres
Waters acres
4. Use of native vegetation and other soft stream bank stabilization techniques must be used where
practicable instead of riprap or other bank hardening methods. If riprap is necessary, it shall not be placed
in the streambed, unless approved by the DWQ.
5. Storm water discharge structures at this site shall be constructed in a manner such that the potential
receiving streams (of the discharge) will not be impacted due to sediment accumulations, scouring or
erosion of the stream banks.
6. A final, written storm water management plan (including a signed and notarized Operation and
Maintenance Agreement) shall be submitted to the 401 Oversight and Express Permitting Unit (2321
Crabtree Blvd., Suite 250, Raleigh, NC, 27604y) within 60 days of the issuance of the 401 Water Quality
Certification. The storm water management plans shall be approved in writing by this Office (before the
impacts specified in this Certification occur. You have the option of using the Express Review Program for
expedited approval of these plans. If you propose to use the Express Review Program, remember to
include the appropriate fee with the plan. The storm water management plan must include construction
plans, specifications, storm water BMP worksheets, and supporting calculations. The storm water best
. management practices are required to be appropriate for the surface water classification and designed to
remove at least 85% TSS according to the most recent version of the NC DENR Storm water Best
Management Practices Manual. These facilities must be designed to treat the runoff from the entire
project, unless otherwise explicitly approved by the Division of Water Quality. Also, before any permanent
building is occupied at the subject site, the facilities (as approved by this Office) shall be constructed and
operational, and the storm water management plan (as approved by this Office) shall be implemented. The
structural storm water practices as approved by this Office as well as drainage patterns must be
maintained in perpetuity. No changes to the structural storm water practices shall be made without written
authorization from the Division of Water Quality.
7. No waste, spoil, solids, or fill of any kind shall occur in wetlands, waters, or riparian areas beyond the
footprint of the impacts depicted in the Preconstruction Notification application. All construction activities
associated with this project shall meet, and/or exceed, those requirements specified in the most recent
version of the North Carolina Sediment and Erosion Control Manual and shall be conducted so that no
violations of state water quality standards, statutes, or rules occur.
8. Sediment and erosion control measures shall not be placed in wetlands or waters to the maximum extent
practicable. If placement of sediment and erosion control devices in wetlands and waters is unavoidable,
they shall. be removed and the natural grade restored within two months of the date the Division of Land
Resources has released the project.
9. Upon completion of the project, the applicant shall complete and return the enclosed "Certificate of
Completion" form to the 401 /Wetlands Unit of the NC Division of Water Quality. Please send photographs
of the upstream and downstream sides of each culvert site to document correct installation, along with the
Certificate of Completion fermi.
00. Continuing Compliance. The applicant (Gateway Homes, LLC; Dave Ransenberg) shall conduct all
activities in a manner so as not to contravene any state water quality standard (including any requirements
for compliance with section 303(d) of the Clean Water Act) and any other appropriate requirements of state
and federal law. If DWQ determines that such standards or laws are not being met (including the failure to
• sustain a designated or achieved use) or that state or federal law is being violated, or that further
conditions are necessary to assure compliance, DWQ may reevaluate and modify this certification to
include conditions appropriate to assure compliance with such standards and requirements in accordance
with 15 A NCAC 2H.0507(d). Before codifying the certification, DWQ shall notify the applicant and the US
Army Corps of Engineers, provide public notice in accordance with 15A NCAC 2H.0503, and provide
opportunity for public hearing in accordance with 15A NCAC 2H.0504. Any new or revised conditions shall
be provided to the applicant in writing, shall be provided to the United States Army Corps of Engineers for
reference in any permit issued pursuant to Section 404 of the Clean Water Act, and shall also become
conditions of the 404 Permit for the project.
If you do not accept any of the conditions of this certification, you may ask for an adjudicatory hearing.
You must act within 60 days of the date that you receive this letter. To ask for a hearing, send a written
petition that conforms to Chapter 1506 of the North Carolina General Statutes to the Office of Administrative
Hearings, 6714 Mail Service Center, Raleigh, N.C. 27699-6714. This certification and its conditions are final
and binding unless you ask for a hearing.
This letter completes the review of the Division of Water Quality under Section 401 of the Clean Water Act.
If you have any questions, please telephone Mr. Alan Johnson in the Mooresville Regional Office at 704-663-
1699 or Ms. Cyndi Karoly in the Central Office in Raleigh 919-733-9721.
Sincerely,
for Coleen H. Sullins
0Attachment: Certificate of Completion Form
cc: Army Corps of Engineers, Asheville
Ian McMillan, Wetlands Unit
George Buchholz, John R McAdams Co., 2905 Meridian Pkwy., Durham 27713
Central Files
File Copy
•
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i eP Ira j, rrta,? <I
--Ock ? e 0-J
Copyright (C) 1998, Maptech, Inc

•
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Soil Map-Mecklenburg County, North Carolina
51k
-O?C's 6aj
•
USDA Natural Resources Web Soil Survey 2.0
Conservation Service National Cooperative Soil Survey
7/12/2007
Page 1 of 3
N Meters
A 0 50 100 200 300
Feet
0 200 400 800 1,200
•
Soil Map-Mecklenburg County, North Carolina
MAP LEGEND
Area of Interest (AOI)
F? Area of Interest (AOI)
Soils
Soil Map Units
Special Point Features
} Blowout
® Borrow Pit
X Clay Spot
Closed Depression
X Gravel Pit
„ Gravelly Spot
Landfill
fly Lava Flow
Marsh
R Mine or Quarry
© Miscellaneous Water
(D Perennial Water
v Rock Outcrop
+ Saline Spot
Sandy Spot
Severely Eroded Spot
Sinkhole
Slide or Slip
Sodic Spot
Spoil Area
1) Stony Spot
MAP INFORMATION
(Z Very Stony Spot Original soil survey map sheets were prepared at publication scale.
Viewing scale and printing scale, however, may vary from the
Wet Spot original. Please rely on the bar scale on each map sheet for proper
1 Other map measurements.
Special Line Features Source of Map: Natural Resources Conservation Service

,y Gully
y Web Soil Survey URL: http://websoilsurvey.nres.usda.gov
Coordinate System: UTM Zone 17N
.:. Short Steep Slope
This product is generated from the USDA-NRCS certified data as of
Other the version date(s) listed below.
Political Features Soil Survey Area: Mecklenburg County, North Carolina
Municipalities Survey Area Data: Version 8, May 7, 2007
Cities Date(s) aerial images were photographed: 1993
® Urban Areas
The orthophoto or other base map on which the soil lines were
water Features compiled and digitized probably differs from the background
oceans imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
,,..,,. Streams and Canals
Transportation

UiW Rails
Roads
N Interstate Highways
ti . US Routes
State Highways
® Local Roads
Other Roads
USDA Natural Resources Web Soil Survey 2.0 7/122007
Um- Conservation Service National Cooperative Soil Survey Page 2 of 3
•
Soil Map-Mecklenburg County, North Carolina
Map Unit Legend
Mecklenburg County, North Carolina (NC119)
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI

I EnB
Enon sandy loam, 2 to 8 percent
slopes
3.4 i
7.2%
EnD Enon sandy loam, 8 to 15
percent slopes 8.1 17.3%
MO Monacan loam 6.8 14.6%
WkD Wilkes loam, 8 to 15 percent
slopes 2.5 5.4%
WkE Wilkes loam, 15 to 25 percent
slopes 25.9 55.4%
Totals for Area of Interest (AOI) 46.8 100.0%
•
•
USDA Natural Resources
.it Conservation Service
Web Soil Survey 2.0
National Cooperative Soil Survey
7/12/2007
Page 3 of 3
Highway 29 WATERSHED SOIL D.B. Hopkins, El
GWH-06040 INFORMATION 7/12/2007
Base SCS CN Data (Assume good condition)
Hydrologic Soil Group
Cover Condition HSG'B' HSG'C' HSG'D'
Impervious 98 98 98
Open 61 74 80
Wooded 55 70 77
=>Site
Assumptions ==>
HSG 'B': 0%
HSG'C': 100%
HSG'D': 0%
Cover Condition Composite SCS CN
Impervious 98
Open 74
Wooded 70
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1 of I

Pre Development
Contents
Pre-Development Cover Conditions and "Tc" Paths
Pre-Development HEC-HMS Output
Pre-Development Watershed Boundary Map
•
Highway 29
GWH-06040
High
GL-0 40
Pre-Development Ooloizic Calculations
Summary
Diaz, El
12/18/2007
Area acres On-site Cover Conditions acres Off-site Cover Conditions acres
Subbasin ID Total On-site Off-site Impervious Wooded Water Open Impervious Wooded Water Open
Subbasin 1 4
2.50 42.50 0.00 0.00 42.50 0.00 0.00 0.00 0.00 0.00 0.00
Subbasin 2 .31
7 7.31 0.00 0.00 7.31 0.00 0.00 0.00 0.00 0.00 0.00
Totals = 49.81 49.81 0.00 0.00 49.81 0.00 0.00 0.00 0.00 0.00 0.00

S
bb
i
ID Drama a Area SCS CN Tc Lag Time
u
as
n [acres] [sq.mi.] [minutes] [minutes]
Subbasin 1 42.50 0.0664 70 19.85 11.91
Subbasin 2 7.31 0.0114 70 16.37 9.82
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pre-Development Hydrologic Calculations Page 1 of 3
Highway 29 Pre-Development Hydrologic Calculations
GWH-06040 Subbasin I
0 #111
Cover Condition SCS CN Comments
Impervious 98 100%HSG'C' Soils
Open 74 100% HSG'C'Soils
Wooded 70 100%HSG'C' Soils
Water 100 100% HSG'C'Soils
A. Watershed Breakdown
Contributing Area SCS CN Area
[acres] Comments
On-Site Impervious 98 0.00 -
On-Site Open 74 0.00 Assume good condition
On-Site Wooded 70 42.50 Assume good condition
On-Site Water 100 0.00 -
Off-Site Impervious 98 0.00 -
Off-Site Open 74 0.00 Assume good condition
Off-Site Wooded 70 0.00 Assume good condition
Off-Site Water 100 0.00 -
Total area = 42.50 acres
0.0664 sq.mi.
Composite SCS CN = 70
• B. Time of Concentration Information
Time of concentration is calculated using SCS TR-55.
Segment 1: Overland Flow Segment 2: Concentrated Flow
Length = 100 ft Length = 326 ft
Height = 6.5 ft Height = 63.5 ft
Slope = 0.0650 ft/ft Slope = 0.1948 ft/ft
Manning's n = 0.40 Wooded - dense underbrush Paved ? = No
P (2-year/24-hour) = 3.44 inches (Charlotte, NC) Velocity = 7.12 ft/sec
Segment Time= 12.93 minutes
Segment 3: Channel Flow
Length = 1632 ft
Height = 29 ft
Slope = 0.0178 ft/ft
Manning's n = 0.045 Natural Channel
Flow Area = 9.00 sf (Assume 3' x 3' Channel)
Wetted Perimeter = 9.00 ft (Assume Y x 3' Channel)
Channel Velocity = 4.41 ft/sec
Segment Time = 0.76 minutes
Segment Time = 6.16 minutes
•
Time of Concentration = 19.85 minutes
SCS Lag Time = 11.91 minutes (SCS Lag = 0.6* Tc)
= 0.1985 hours
Time Increment = 3.45 minutes (= 0.29*SCS Lag)
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pre-Development Hydrologic Calculations
J.C. Diaz, El
12/18/2007
Page 2 of 3
Highway 29 Pre-Development Hydrologic Calculations
GWH-06040 Subbasin 2
•
Cover Condition SCS CN Comments
Impervious 98 100% HSG'C'Soils
Open 74 100%HSG'C' Soils
Wooded 70 100% HSG'C'Soils
Water 100 100% HSG'C'Soils
A. Watershed Breakdown
Contributing Area SCS CN Area
[acres] Comments
On-Site Impervious 98 0.00 -
On-Site Open 74 0.00 Assume good condition
On-Site Wooded 70 7.31 Assume good condition
On-Site Water 100 0.00 -
Off-Site Impervious 98 0.00 -
Off-Site Open 74 0.00 Assume good condition
Off-Site Wooded 70 0.00 Assume good condition
Off-Site Water 100 0.00 -
Total area = 7.31 acres
0.0114 sq.mi.
Composite SCS CN = 70
B. Time of Concentration Information
Time of concentration is calculated usin€
Segment 1: Overland Flow
Length = 100
Height = 6
Slope = 0.0600
Manning's n = 0.40
P (2-year/24-hour) = 3.44
Segment Time = 13.35
Segment 3: Channel Flow
Length = 362
Height = 20
Slope = 0.0552
Manning's n = 0.045
Flow Area = 2.25
Wetted Perimeter = 4.50
Channel Velocity = 4.90
SCS TR-55.
ft
ft
ft/ft
Wooded - dense underbrush
inches (Charlotte, NC)
minutes
ft
ft
ft/ft
Natural Channel
sf (Assume 1.5'x 1.5' Channel)
ft (Assume 1.5'x 1.5' Channel)
ft/sec
Segment Time = 1.23 minutes
•
Segment 2: Concentrated Flow
Length = 268 ft
Height = 34 ft
Slope = 0.1269 ft/ft
Paved ? = No
Velocity = 5.75 ft/sec
Segment Time = 0.78 minutes
J.C. Diaz, El
12/18/2007
Time of Concentration = 16.37 minutes
SCS Lag Time = 9.82 minutes (SCS Lag = 0.6* Tc)
0.1637 hours
Time Increment = 2.85 minutes (= 0.29*SCS Lag)
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pre-Development Hydrologic Calculations Page 3 of 3

•
Project : GWH-06040
Basin Model : Pre-Development
'Dec 18 10:28:39 EST 2007
HEC-HMS
0
Project: GWH-06040 Simulation Run: Pre-2-Year
Start of Run: 12Jul2007, 00:00 Basin Model: Pre-Development
End of Run: 13Jul2007, 00:01 Meteorologic Model: 2-Year
Compute Time: 18Dec2007, 10:28:09 Control Specifications: 1min-dt
Volume Units: AC-FT
Hydrologic
Element Drainage Area
(M12) Peak Discharge
(CFS) Time of Peak Volume
(AC-FT)
Subbasin-1 0.0664 43.33 12Ju12007, 12:15 3.42
Subbasin-2 4----1 8.00 12Ju12007, 12:13 0.59
•
0
is Project: GWH-06040 Simulation Run: Pre-10-Year
Start of Run: 12Jul2007, 00:00 Basin Model: Pre-Development
End of Run: 13Ju12007, 00:01 Meteorologic Model: 10-Year
Compute Time: 18Dec2007, 10:28:13 Control Specifications:1 min-dt
Volume Units: AC-FT
Hydrologic
Element Drainage Area
(M12) Peak Discharge
(CFS) Time of Peak Volume
(AC-FT)
Subbasin-1 0.0664 88.03 12Ju12007, 12:14 7.21
Subbasin-2 0.0114 16.12 12Ju12007, 12:12 1.24
•
0
•
•
Post-Development
Contents
•
Post-Development Cover Conditions and "Tc" Paths
Post-Development HEC-HMS Output
Post-Development Watershed Boundary Map
Highway 29
G"-06040
Highw Post-Development 4-ologic Calculations Joiaz, EI
GWH-0 40 Summary 12/18/2007
Area acres On-site Cover Conditions acres Off-site Cover conaitions acres
Subbasin ID Total On-site Off-site Impervious Wooded Water Open Impervious Wooded Water Open
Subbasin 1 - To Pond 1 15.11 13.55 1.56 7.33 0.00 0.00 6.22 0.54 0.00 0.00 1.02
Subbasin 1 - To Pond 2 12.00 11.72 0.28 7.18 0.00 0.00 4.54 0.00 0.00 0.00 0.28
Subbasin 1 - To Pond 3 2.48 2.47 0.01 1.44 0.00 0.00 1.03 0.00 0.00 0.00 0.01
Subbasin 1 - To Pond 4 6.26 6.09 0.17 4.28 0.00 0.00 1.81 0.00 0.00 0.00 0.17
Subbasin 1 - Bypass to Reach 9.96 9.96 0.00 0.00 0.00 0.00 9.96 0.00 0.00 0.00 0.00
Subbasin 1 - Bypass 5.38 5.38 0.00 0.03 0.00 0.00 5.35 0.00 0.00 0.00 0.00
Subbasin 2 0.64 0.64 0.00 0.21 0.00 0.00 0.43 0.00 0.00 0.00 0.00
Tntnk = 51.83 49.81 2.02 20.47 0.00 0.00 29.34 0.54 0.00 0.00 1.48
Subbasin ID _.--
[acres] - __
[sq.mi.] SCS CN
[minutes] °
[minutes]
Subbasin 1 - To Pond 1 15.11 0.0236 87 5.00 3.00
Subbasin 1 - To Pond 2 12.00 0.0188 88 5.00 3.00
Subbasin 1 - To Pond 3 2.48 0.0039 88 5.00 3.00
Subbasin 1 - To Pond 4 6.26 0.0098 90 5.00 3.00
Subbasin 1 - Bypass to Reach 9.96 0.0156 74 5.00 3.00
Subbasin 1 - Bypass 5.38 0.0084 74 5.00 3.00
Subbasin 2 0.64 0.0010 82 5.00 3.00
* Note: All detention facilities are in Subbasin 1. There is no detention in Subbasin 2.
X:\Projects\GWHIGWH-06040\Storm\Construction Drawings\Design Files\Post-Development Hydrologic Calculations Page 1 of 8
Highway 29 Post-Development Hydrologic Calculations J.C. Diaz, El
GWH-06040 Subbasin 1 - To Pond 1 12/18/2007

Cover Condition SCS CN Comments
Impervious 98 100%HSG'C' Soils
Open 74 100%HSG'C' Soils
Wooded 70 100%HSG'C' Soils
Water 100 100%HSG'C' Soils
A. Watershed Breakdown
Contributing Area SCS CN Area
[acres] Comments
On-Site Impervious 98 7.33 -
On-Site Open 74 6.22 Assume good condition
On-Site Wooded 70 0.00 Assume good condition
On-Site Water 100 0.00
Off-Site Impervious 98 0.54 -
Off-Site Open 74 1.02 Assume good condition
Off-Site Wooded 70 0.00 Assume good condition
Off-Site Water 100 0.00 -
Total area = 15.11 acres
0.0236 sq.mi.
Composite SCS CN = 87
B. Time of Concentration Information
Time of concentration is calculated using the SCS Segmental Approach (TR-55). Assumed minimum of 5 minutes.
Time of Concentration = 5.00 minutes
SCS Lag Time = 3.00 minutes (SCS Lag = 0.6* Tc)
Time Increment = 0.87 minutes (= 0.29*SCS Lag)
•
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Post-Development Hydrologic Calculations Page 2 of 8
Highway 29 Post-Development Hydrologic Calculations J.C. Diaz, El
GWH-06040 Subbasin 1 - To Pond 2 12/18/2007
•
Cover Condition SCS CN Comments
Impervious 98 100% HSG'C'Soils
Open 74 100% HSG 'C' Soils
Wooded 70 100% HSG'C'Soils
Water 100 100% HSG'C'Soils
A. Watershed Breakdown
Contributing Area SCS CN Area
[acres] Comments
On-Site Impervious 98 7.18 -
On-Site Open 74 4.54 Assume good condition
On-Site Wooded 70 0.00 Assume good condition
On-Site Water 100 0.00 -
Off-Site Impervious 98 0.00 -
Off-Site Open 74 0.28 Assume good condition
Off-Site Wooded 70 0.00 Assume good condition
Off-Site Water 100 0.00 -
Total area = 12.00 acres
0.0188 sq.mi.
Composite SCS CN = 88
• B. Time of Concentration Information
Time of concentration is calculated using the SCS Segmental Approach (TR-55). Assumed minimum of 5 minutes.
Time of Concentration = 5.00 minutes
SCS Lag Time = 3.00 minutes (SCS Lag = 0.6* Tc)
Time Increment = 0.87 minutes (= 0.29*SCS Lag)
•
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Post-Development Hydrologic Calculations Page 3 of 8
Highway 29 Post-Development Hydrologic Calculations
GWH-06040 Subbasin 1 - To Pond 3
•
Cover Condition SCS CN Comments
Impervious 98 100% HSG'C'Soils
Open 74 100%HSG'C' Soils
Wooded 70 100%HSG'C' Soils
Water 100 100%HSG'C' Soils
A. Watershed Breakdown
Contributing Area SCS CN Area
[acres] Comments
On-Site Impervious 98 1.44 -
On-Site Open 74 1.03 Assume good condition
On-Site Wooded 70 0.00 Assume good condition
On-Site Water 100 0.00 -
Off-Site Impervious 98 0.00 -
Off-Site Open 74 0.01 Assume good condition
Off-Site Wooded 70 0.00 Assume good condition
Off-Site Water 100 0.00 -
Total area = 2.48 acres
0.0039 sq.mi.
Composite SCS CN = 88
. B. Time of Concentration Information
Time of concentration is calculated using the SCS Segmental Approach (TR-55). Assumed minimum of 5 minutes.
•
Time of Concentration = 5.00 minutes
SCS Lag Time = 3.00 minutes (SCS Lag = 0.6* Tc)
Time Increment = 0.87 minutes (= 0.29*SCS Lag)
J.C. Diaz, El
12/18/2007
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Post-Development Hydrologic Calculations Page 4 of 8
Highway 29 Post-Development Hydrologic Calculations J.C. Diaz, El
GWH-06040 Subbasin I - To Pond 4 12/18/2007
0
Cover Condition SCS CN Comments
Impervious 98 100% HSG'C'Soils
Open 74 100% HSG 'C' Soils
Wooded 70 100%HSG'C' Soils
Water 100 100%HSG'C' Soils
A. Watershed Breakdown
Contributing Area SCS CN Area
[acres] Comments
On-Site Impervious 98 4.28 -
On-Site Open 74 1.81 Assume good condition
On-Site Wooded 70 0.00 Assume good condition
On-Site Water 100 0.00 -
Off-Site Impervious 98 0.00 -
Off-Site Open 74 0.17 Assume good condition
Off-Site Wooded 70 0.00 Assume good condition
Off-Site Water 100 0.00 -
Total area = 6.26 acres
0.0098 sq.mi.
Composite SCS CN = 90
• B. Time of Concentration Information
Time of concentration is calculated using the SCS Segmental Approach ('1'R-55). Assumed minimum of 5 minutes.
•
Time of Concentration = 5.00 minutes
SCS Lag Time = 3.00 minutes (SCS Lag = 0.6* Tc)
Time Increment = 0.87 minutes (= 0.29*SCS Lag)
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Post-Development Hydrologic Calculations Page 5 of 8
Highway 29 Post-Development Hydrologic Calculations
GWH-06040 Subbasin 1 - Bypass to Reach
•
Cover Condition SCS CN Comments
Impervious 98 100% HSG 'C' Soils
Open 74 100% HSG 'C' Soils
Wooded 70 100%HSG'C'Soils
Water 100 100% HSG'C'Soils
A. Watershed Breakdown
Contributing Area SCS CN Area
[acres] Comments
On-Site Impervious 98 0.00 -
On-Site Open 74 9.96 Assume good condition
On-Site Wooded 70 0.00 Assume good condition
On-Site Water 100 0.00 -
Off-Site Impervious 98 0.00 -
Off-Site Open 74 0.00 Assume good condition
Off-Site Wooded 70 0.00 Assume good condition
Off-Site Water 100 0.00 -
Total area = 9.96 acres
0.0156 sq.mi.
Composite SCS CN = 74
• B. Time of Concentration Information
Time of concentration is calculated using the SCS Segmental Approach (TR-55). Assumed minimum of 5 minutes.
Time of Concentration = 5.00 minutes
SCS Lag Time = 3.00 minutes (SCS Lag = 0.6* Tc)
Time Increment = 0.87 minutes (= 0.29*SCS Lag)
•
J.C. Diaz, El
12/18/2007
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Post-Development Hydrologic Calculations Page 6 of 8
Highway 29 Post-Development Hydrologic Calculations
GWH-06040 Subbasin I - Bypass
is moomm's,
Cover Condition SCS CN Comments
Impervious 98 100%HSG'C' Soils
Open 74 100%HSG'C' Soils
Wooded 70 100%HSG'C' Soils
Water 100 100%HSG'C' Soils
A. Watershed Breakdown
Contributing Area SCS CN Area
[acres] Comments
On-Site Impervious 98 0.03 -
On-Site Open 74 5.35 Assume good condition
On-Site Wooded 70 0.00 Assume good condition
On-Site Water 100 0.00 -
Off-Site Impervious 98 0.00 -
Off-Site Open 74 0.00 Assume good condition
Off-Site Wooded 70 0.00 Assume good condition
Off-Site Water 100 0.00 -
Total area = 5.38 acres
0.0084 sq.mi.
Composite SCS CN = 74
0 B. Time of Concentration Information
Time of concentration is calculated using the SCS Segmental Approach (TR-55). Assumed minimum of 5 minutes.
•
Time of Concentration = 5.00 minutes
SCS Lag Time = 3.00 minutes (SCS Lag = 0.6* Tc)
Time Increment = 0.87 minutes (= 0.29*SCS Lag)
J.C. Diaz, El
12/18/2007
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Post-Development Hydrologic Calculations Page 7 of 8
Highway 29 Post-Development Hydrologic Calculations
GWH-06040 Reach
Length =
Slope =
Manning's n =
Flow Area =
Wetted Perimeter =
Channel Velocity =
J.C. Diaz, El
4/4/2008
1379 ft Begin EL. 594.Oft
0.0116 ft/ft End EL. 578.011
0.045 natural stream
25.00 sf (Assume 3'x3' channel)
15.00 ft (Assume 3'x3' channel)
5.01 ft/sec
Segment Time = 4.58 minutes
TOTAL TRAVEL TIME = 4.58 MINUTES
•
•
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Post-Development Hydrologic Calculations Page 8 of 9
Highway 29 Post-Development Hydrologic Calculations J.C. Diaz, El
GWH-06040 Subbasin 2 12/18/2007
0 w-UMMMMom
Cover Condition SCS CN Comments
Impervious 98 100%HSG'C' Soils
Open 74 100%HSG'C' Soils
Wooded 70 100%HSG'C' Soils
Water 100 100%HSG'C' Soils
F?I?Nr,
A. Watershed Breakdown
Contributing Area SCS CN Area
[acres] Comments
On-Site Impervious 98 0.21 -
On-Site Open 74 0.43 Assume good condition
On-Site Wooded 70 0.00 Assume good condition
On-Site Water 100 0.00 -
Off-Site Impervious 98 0.00 -
Off-Site Open 74 0.00 Assume good condition
Off-Site Wooded 70 0.00 Assume good condition
Off-Site Water 100 0.00 -
Total area = 0.64 acres
0.0010 sq.mi.
Composite SCS CN = 82
• B. Time of Concentration Information
Time of concentration is calculated using the SCS Segmental Approach (TR-55). Assumed minimum of 5 minutes.
Time of Concentration = 5.00 minutes
SCS Lag Time = 3.00 minutes (SCS Lag = 0.6* Tc)
Time Increment = 0.87 minutes (= 0.29*SCS Lag)
•
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Post-Development Hydrologic Calculations Page 8 of 8
•
•
0
Project: GWH-06040 Simulation Run: Post-2-Year
Start of Run: 12Jul2007, 00:00 Basin Model: Post-Development
End of Run: 13Jul2007, 00:01 Meteorologic Model: 2-Year
Compute Time: 19Dec2007, 10:09:21 Control Specifications:1 min-dt
•
Volume Units: AC-FT
Hydrologic
Element Drainage Area
(M12) Peak Discharg
(CFS) Time of Peak Volume
(AC-FT)
Bypass 0.0084 11.29 12Ju12007, 1205 0.54
Bypass to Reach 0.0156 20.96 12Ju12007, 12:05 1.00
Junction-1 0.0382 21.46 12Ju12007, 12:05 2.46
Pond 1 0.0236 0.47 12Ju12007, 23:31 0.36
Pond 2 0.0187 3.99 12Ju12007, 12:36 1.43
Pond 3 0.0039 0.04 12Ju12007, 17:20 0.04
Pond 4 0.0098 10.48 12Ju12007, 12:12 0.75
Reach-1 0.0382 21.46 12Ju12007, 12:09 2.46
Subbasin 1 0.0800 37.26 12Ju12007, 12:10 4.10
Subbasin 2 0.0010 1.99 12M2007, 12:04 0.09
To Pond 1 0.0236 57.73 12Ju12007, 12:04 2.68
To Pond 2 0.0187 47.44 12Ju12007, 12:04 2.21
To Pond 3 0.0039 9.89 12Ju12007, 12:04 0.46
To Pond 4 0.0098 26.63 12Ju12007, 12:04 1.25
0
Project: GWH-06040 Simulation Run: Post-10-Year
Start of Run: 12Ju12007, 00:00 Basin Model: Post-Development
End of Run: 13J02007, 00:01 Meteorologic Model: 10-Year
Compute Time: 19Dec2007, 10:09:26 Control Specifications:1 min-dt
•
Volume Units: AC-FT
Hydrologic
Element Drainage Area
(M12) Peak Discharg
(CFS) Time of Peak Volume
(AC-FT)
Bypass 0.0084 20.10 12Ju12007, 12:04 1.06
Bypass to Reach 0.0156 37.32 12Ju12007, 12:04 1.97
Junction-1 0.0382 41.87 12Ju12007, 12:05 5.11
Pond 1 0.0236 13.64 12Ju12007, 12:31 2.17
Pond 2 0.0187 20.36 12Ju12007, 12:18 2.85
Pond 3 0.0039 0.91 12Ju12007, 12:51 0.29
Pond 4 0.0098 30.74 12Ju12007, 12:07 1.52
Reach-1 0.0382 41.87 12Ju12007, 12:09 5.10
Subbasin 1 0.0800 87.09 12Ju12007, 12:07 9.85
Subbasin 2 0.0010 3.12 12Ju12007, 12:04 0.16
To Pond 1 0.0236 83.95 12Ju12007, 12:04 4.50
To Pond 2 0.0187 68.06 12Ju12007, 12:04 3.67
To Pond 3 0.0039 14.19 12Ju12007, 12:04 0.76
To Pond 4 0.0098 37.20 12Ju12007, 12:04 12.03
•
• Project : GWH-06040 Simulation Run : Post-2-Year Reservoir: Pond 1
Start of Run : 12Ju12007, 00:00 Basin Model : Post-Development
End of Run : 13Jul2007, 00:01 Meteorologic Model : 2-Year
Compute Time : 14Dec2007, 09:12:18 Control Specifications : 1 min-dt
Volume Units : AC-FT
Computed Results... .
Peak Inflow : 57.73 (CFS) Date/Time of Peak Inflow : 12Ju12007, 12:04
Peak Outflow : 0.47 (CFS) Date/Time of Peak Outflow : 12Ju12007, 23:31
Total Inflow : 2.08 (AC-FT) Peak Storage : 2.32 (AC-FT)
Total Outflow: 0.36 (AC-FT) Peak Elevation : 593.41 (FT)
:................. ................................................ .... ............................. ....................................... ........................ .........................................................................................................................................
•
•
. Project : GWH-06040 Simulation Run : Post-10-Year Reservoir: Pond 1
Start of Run : 12Ju12007, 00:00 Basin Model : Post-Development
End of Run : 13Ju12007, 00:01 Meteorologic Model : 10-Year
Compute Time : 14Dec2007, 09:12:44 Control Specifications : 1 min-dt
Volume Units : AC-FT
Computed Results
Peak Inflow : 83.95 (CFS)
Peak Outflow: 13.64(CFS)
Total Inflow: 4.50 (AC-FT)
Total Outflow:
.................................................................. 2.17 (AC-FT)
............................................
Date/Time of Peak Inflow :
Date/Time of Peak Outflow
Peak Storage :
Peak Elevation
12Ju12007, 12:04
12Ju12007, 12:31
2.60 (AC-FT)
593.86 (FT)
..........................................................
0

•
•
Project : GWH-06040 Simulation Run :
Start of Run : 12Jul2007, 00:00
End of Run : 13Jul2007, 00:01
Compute Time : 18Dec2007, 11:21:29
Volume Units
100-Year Tail Water Reservoir: Pond 1
Basin Model : Post-100
Meteorologic Model : 100-Year
Control Specifications : 1 min-dt
AC-FT
Computed Results .........
Peak Inflow: 111.98 (CFS) Date/Time of Peak Inflow : 12Jul2007, 12:04
Peak Outflow: 79.84(CFS) Date/Time of Peak Outflow: 12Jul2007, 12:08
Total Inflow=: 7.27 (AC-FT) Peak Storage : 0.82 (AC-FT)
Total Outflow :
:.................................................................. 7.24 (AC-FT)
..................................................... Peak Elevation :
.............. ....................................................................................... 594.79 (FT)
................. ................. ...........................
0
• Project : GWH-06040 Simulation Run : Post-2-Year Reservoir: Pond 2
Start of Run : 12Jul2007, 00:00 Basin Model : Post-Development
End of Run : 13Ju12007, 00:01 Meteorologic Model : 2-Year
Compute Time : 14Dec2007, 09:12:18 Control Specifications : 1 min-dt
Volume Units : AC-FT
CorTputed Results
Peak Inflow : 47.44 (CFS) DatefTime of Peak Inflow : 12Ju12007, 12:04
Peak Outflow : 3.99 (CFS) DatefTime of Peak Outflow : 12Jul2007, 12:36
Total Inflow : 2.21 (AC-FT) Peak Storage : 1.26 (AC-FT)
Total Outflow :
...... . . .. ...................................... 1.43 (AC-FT)
............................. .. .. ................. . Peak Elevation :
............................ . . . .. .. .......................... ... . ........ _ .......................... 607.61 (FT)
.... . .. . . ..... . . ........ . ......... . . . .. ... .... ....... ........................ . .
s
•
Project : GWH-06040 Simulation Run : Post-110-Year Reservoir: Pond 2
Start of Run : 12Ju12007, 00:00 Basin Model : Post-Development
End of Run : 13Jul2007, 00:01 Meteorologic Model : 10-Year
Compute Time : 14Dec2007, 09:12:44 Control Specifications : 1 min-dt
Volume Units : AC-FT
Corruted Results . ......
Peak Inflow : 68.06 (CFS)
Peak Outflow : 20.36 (CFS)
Total Inflow: 3.67 (AC-FT)
Total Outflow:
...................................................... 2.86 (AC-FT)
..........................................
Date/Time of Peak Inflow : 12Ju12007, 12:04
Date/Time of Peak Outflow: 12Ju12007, 12:18
Peak Storage : 1.83 (AC-FT)
Peak Elevation : 608.88 (F T)
•
0
•
•
Project : GWH-06040 Simulation Run:
Start of Run : 12Jul2007, 00:00
End of Run : 13Jul2007, 00:01
Compute Time : 18Dec2007, 11:21:29
Volume Units :
Computed Results
Peak Inflow : 91.19 (CFS)
Peak Outflow : 74.69 (CFS)
Total Inflow : 6.99 (AC-FT)
Total Outflow :
................................. ...... ......... ......... . 5.78 (AC-FT)

.........
.................................
100-Year Tail Water Reservoir: Pond 2
Basin Model: Post-100
Meteorologic Model : 100-Year
Control Specifications : 1 min-dt
AC-FT
Date/Time of Peak Inflow : 12JuI2007, 12:04
DatelTime of Peak Outflow : 12Ju12007, 12:07
Peak Storage : 1.47 (AC-FT)
Peak Elevation : 809.59 (FT)
....................................................................................................................................................
0
• Project : GWH-06040 Simulation Run : Post-2-Year Reservoir: Pond 3
Start of Run : 12Jul2007, 00:00 Basin Model : Post-Development
End of Run : 13Jul2007, 00:01 Meteorologic Model : 2-Year
Compute Time : 14Dec2007, 09:12:18 Control Specifications : 1 min-dt
Volume Units : AC-FT
CorTputed Results
Peak Inflow: 9.89 (CFS) Date/Time of Peak Inflow : 12Ju12007, 12:04
Peak Outflow: 0.04 (CFS) Date/Time of Peak Outflow : 12Ju12007, 17:20
Total Inflow: 0.46 (AC-FT) Peak Storage : 0.42 (AC-FT)
Total Outflow: 0.04 (AC-FT) Peak Elevation : 606.16 (F T)
........................ ................................................................... ........................................... .......................................................................................................................................
•
•
• Project : GWH-06040 Simulation Run: Post-10-Year Reservoir: Pond 3
Start of Run : 12Jul2007, 00:00 Basin Model : Post-Development
End of Run : 13Ju12007, 00:01 Meteorologic Model : 10-Year
Compute Time : 14Dec2007, 09:12:44 Control Specifications : 1 min-dt
Volume Units
Corrputed Results . ..............
Peak Inflow : 14.19 (CFS)
Peak Outflow : 0.91 (CFS)
Total Inflow : 0.70 (AC-FT)
Total Outflow :
.......................... ........................ 0.29 (AC-FT)
.....................
... ........... .
AC-FT
Date/Time of Peak Inflow :
DatelTime of Peak Outflow
Peak Storage :
Peak Elevation
•
12Ju12007, 12:04
12Ju12007, 12:61
0.60 (AC- F T)
806.49 (FT)
...........................................................
0
•
•
Project : GWH-06040 Simulation Run :
Start of Run : 12Ju12007, 00:00
End of Run : 13Jul2007, 00:01
Compute Time : 18Dec2007, 11:21:29
Volume Units :
°Corrputed Results
Peak Inflow : 19.02 (CFS)
Peak Outflow : 16.61 (CFS)
Total Inflow : 1.26 (AC-FT)
Total Outflow :
:............................................................ ...... 1.26 (AC-FT)
....................................... ....
100-Year Tail Water Reservoir: Pond 3
Basin Model : Post-100
Meteorologic Model : 100-Year
Control Specifications : 1 min-dt
AC-FT
Date/Time of Peak Inflow : 12Ju12007, 12:04
Date/Time of Peak Outflow: 12Jul2007, 12:06
Peak Storage : 0.10 (AC-FT)
Peak Elevation : 606.92 (FT)
.................................. .-............................. ..................................... ..._......._______ ...
0
• Project : GWH-06040 Simulation Run : Post-2-Year Reservoir: Pond 4
Start of Run : 12Jul2007, 00:00 Basin Model : Post-Development
End of Run : 13Jul2007, 00:01 Meteorologic Model : 2-Year
Compute Time : 19Dec2007, 10:09:21 Control Specifications : 1 min-dt
Volume Units
AC-FT
Computed Results
Peak Inflow: 26.03 (CFS)
Peak Outflow : 10.48 (CFS)
Total Inflow: 1.25 (AC-FT)
Total Outflow: 0.75 (AC-FT)
DatelTime of Peak Inflow :
Date/Time of Peak Outflow:
Peak Storage :
Peak Elevation
12Ju12007, 12:04
12Ju12007, 12:12
0.59 (AC- F T)
596.30 (FT)
•
0
• Project : GWH-06040 Simulation Run : Post-10-Year Reservoir: Pond 4
Start of Run : 12Ju12007, 00:00 Basin Model : Post-Development
End of Run : 13Jul2007, 00:01 Meteorologic Model : 10-Year
Compute Time : 191Dec2007, 10:09:26 Control Specifications : 1 min-dt
Volume Units : AC-FT
Computed Results
Peak Inflow : 37.20 (CFS) Date/Time of Peak Inflow : 12Ju12007, 12:04
Peak Outflow : 30.74 (CFS) DatelTime of Peak Outflow : 12Ju12007, 12:07
Total Inflow: 2.03 (AC-FT) Peak Storage : 0.69 (AC-FT)
Total Outflow: 1.52 (AC-FT) Peak Elevation : 598.64(FT)
.................................. ...................... .............. ......... ..........................
..................................................._........
•
0
•
•
Project : GWH-06040 Simulation Run :
Start of Run : 12Jul2007, 00:00
End of Run : 13Jul2007, 00:01
Compute Time : 18Dec2007, 11:21:29
100-Year Tail Water Reservoir: Pond 4
Basin Model : Post-100
Meteorologic Model : 100-Year
Control Specifications : 1 min-dt
Volume Units : AC-FT
,..Computed Results
Peak Inflow : 48.95 (CFS) Date/Time of Peak Inflow : 12Ju12007, 12:04
Peak Outflow : 42.87 (0FS) Date/Time of Peak Outflow: 12Ju12007, 12:06
Total Inflow : 3.26 (A0-FT) Peak Storage : 0.23 (AC-FT)
Total Outflow:
................................................................ 3.26 (AG-FT)
................................................... Peak Elevation :
..................................... _................................................................ 596.80 (FT)
..................................................._..........
0
Highway 29 Above NWSE J.C. Diaz, El
GWH-6040 Pond#1 Calculations 4/21/2008
• Average Incremental Accumulated Estimated
Contour Contour Contour Contour Stage
Contour Stage Area Area Volume Volume w/ S-S Fxn
(feet) (feet) (SF) (SF) (CF) (CF) (feet)
589.0 0.0 16930
590.0 1.0 19237 18084 18084 18084 1.03
591.0 2.0 21823 20530 20530 38614 1.96
592.0 3.0 24417 23120 23120 61734 2.91
593.0 4.0 27082 25750 25750 87483 3.91
594.0 5.0 29802 28442 28442 115925 4.96
595.0 6.0 32580 31191 31191 147116 6.07
596.0 7.0 35414 33997 33997 181113 7.24
•
Ks= 17413
b = 1.1831
•
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond#1 Calculations Page 1
Highway 29 S-S Function J.C. Diaz, EI
GWH-6040 Pond# 1 Calculations 4/21/2008
• => Stage - Storage Function
Ks = 17413
b = 1.1831
zo = ;89.00
Elevation Stora a Worst Case Scenario Stora
feet [cfl [acre-feet] [acre-feet]
589.00 0 0.000 -
589.20 2594 0.060
589.40 5889 0.135
589.60 9515 0.218
589.80 13373 0.307
590.00 17413 0.400
590.20 21605 0.496 -
590.40 25927 0.595 -
590.60 30365 0.697 -
590.80 34905 0.801 -
591.00 39539 0.908 -
591.20 44258 1.016 -
591.40 49057 1.126 -
591.60 53930 1.238 -
591.80 58872 1.352 -
592.00 63879 1.466 -
592.20 68947 1.583 -
592.40 74074 1.701 -
•
592.60 79257 1.819
592.80 84492 1.940 -
593.00 89778 2.061 -
593.20 95113 2.183 -
593.40 100495 2.307 -
593.60 105921 2.432 0.062
593.80 111391 2.557 0.188
594.00 116903 2.684 0.315
594.20 122455 2.811 0.442
594.40 128047 2.940 0.570
594.60 133676 3.069 0.700
594.80 139343 3.199 0.830
595.00 145046 3.330 0.961
595.20 150783 3.462 1.092
595.40 156554 3.594 1.225
595.60 162359 3.727 1.358
595.80 168196 3.861 1.492
-
596.00 174064 3.996 1.6D
0
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond#1 Calculations Page 2
Highway 29 Below NWSE J.C. Diaz, El
GWH-6040 Pond#I Calculations 4/21/2008
• Average Incremental Accumulated Estimated
Contour Contour Contour Contour Stage
Contour Stage Area Area Volume Volume w/ S-S Fxn
(feet) (feet) (SF) (SF) (CF) (CF) (feet)
584.0 0.0 5187
585.0 1.0 7640 6414 6414 6414 1.02
586.0 2.0 9048 8344 8344 14758 1.96
587.0 3.0 10513 9781 9781 24538 2.91
588.0 4.0 13453 11983 11983 36521 3.96
589.0 5.0 16788 15121 15121 51642 5.19
•
Storage vs. Stage
60000
50000 ?
Y = 6226.x1.284
LL 40000 RI = 0.997
U
rn 30000
w
N 20000
10000
0
0.0 1.0 2.0 3.0 4.0 5.0 6.0
Stage (feet)
Ks = 6226.2
b = 1.2843
•
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond#1 Calculations Page 3
Highway 29 Forebay 1 J.C. Diaz, El
GWH-6040 Pond#1 Calculations 4/21/2008
• Average Incremental Accumulated Estimated
Contour Contour Contour Contour Stage
Contour Stage Area Area Volume Volume w/ S-S Fxn
(feet) (feet) (SF) (SF) (CF) (CF) (feet)
584.0 0.0 90
585.0 1.0 201 146 146 146 1.02
586.0 2.0 362 282 282 427 1.92
587.0 3.0 563 463 463 890 2.96
588.0 4.0 806 685 685 1574 4.13
is
Storage vs. Stage
1800
1600
1400 y = 139.9x1.706
1200 RI = 0.997
LL
m 1000
CO
T 800
0
U) 600
400
200
0
0.0 1.0 2.0 3.0 4.0 5.0
Stage (feet)
Ks = 139.93
b = 1.7069
is
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond#1 Calculations Page 4
Highway 29 Forebay 2 J.C. Diaz, El
GWH-6040 Pond#1 Calculations 4/21/2008
• Average Incremental Accumulated Estimated
Contour Contour Contour Contour Stage
Contour Stage Area Area Volume Volume w/ S-S Fxn
(feet) (feet) (SF) (SF) (CF) (CF) (feet)
584.0 0.0 1077
585.0 1.0 1405 1241 1241 1241 1.01
586.0 2.0 1761 1583 1583 2824 1.95
587.0 3.0 2146 1954 1954 4778 2.97
588.0 4.0 2557 2352 2352 7129 4.08
•
Storage vs. Stage
8000
7000 y = 12 19.x1.255
6000 R2 = 0.998
v 5000
m 4000
y 3000
2000
1000
0
0.0 1.0 2.0 3.0 4.0 5.0
Stage (feet)
Ks = 1219.1
b = 1.2554
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond#1 Calculations Page 5
Highway 29 Forebay and Surface Area J.C. Diaz, El
GWH-6040 Pond#1 Calculations 4/21/2008
Per NCDENR "Stormwater Best Management Practices ", the forebay volume should equal about 20% of the total
basin volume.
A. Water Quality Pond - Below Normal Pool
NWSE = 589
Stage - Storage Function
Ks = 6226.2
b= 1.2843
Zo = 584
Volume = 49194 ft3
B. Forebay Volume
Forebay 1: Volume
Stage - Storage Function
Ks = 139.93
b= 1.7069
Zo = 584
Volume = 1491 ft3
Forebay 2: Volume
Stage - Storage Function
Ks= 1219.1
b= 1.2554
Zo = 584
3
Volume = 6948 ft
% Foreba = 17.2%

Impervious Area = 7.87 acres
Drainage Area = 15.11 acres
% Impervious = 52%
Average Depth = Accumulated Contour Volume / Surface Area
ACV = 51642 cf
SA = 16788 sf
Average Depth = 3.1 ft.
From the Greensboro Stormwater Handbook, the required SA/DA ratio =>
3.0 3.1 4.0
Lower Boundary => 50.0 2.06 1.73
Site % impervious => 52.1 2.13 2.11 1.79
Upper Boundary => 60.0 2.40 2.03
Area Required = 13856 sq.ft.
• Area Provided = 16788 s q.11.
X:\Projects\GWMGWH-06040\Storm\Construction Drawings\Design Files\Pond# 1 Calculations Page 6
Highway 29 Water Quality Volume J.C. Diaz, El
GWH-6040 Pond#1 Calculations 4/21/2008
Ks = 17413
b = 1.1831
Calculation of Runoff Volume required for storage
The runoff to the pond for the V storm detention requirement is calculated using the SCS curve
number method. Impervious areas that directly enter the pond are counted as Directly Connected
Impervious Areas (DCIAs). No infiltration calculation will be provided for these areas. Areas
not directly connected will be accounted for in a composite curve number.
Using basic SCS runoff methodology, with no adjus
to initial abstractions (0.2*S and 0.8*S).
Impervious Area, directly connected (DCIA) _
@CN=
Other areas draining to pond (not DCIA) _
@CN=
tments made
7.87 acres
98
7.24 acres
74
Runoff from DC14s =y
Precipitation amount = 1.0 inches
S = 0.204 inches (calculated)
Q* = 0.791 inches (calculated)
Runoff volume= 22595 CF
• Runoff from non-connected areas -
Precipitation amount = 1.0 inches
S = 3.514 inches (calculated)
Q* = 0.023 inches (calculated)
Runoff volume= 610 CF
Therefore, total runoff from precipitation in question = 23204 CF
This amount of runoff must be stored in the pond above normal pool elevation,
and be released in a period of two (2) to five (5) days, by an inverted PVC
siphon, the invert end of which is set at permanent pool elevation.
Calculation of depth required for runoff storage pool (above normal pool)
Normal pool depth (above invert) = 0.00 feet
Storage provided at permanent pool depth = 0 CF (calculated)
Total storage required for normal + storage pool = 23204 CF
Stage (above invert) associated with this storage = 1.27 feet
1 Therefore, depth required above normal pool for storm storage = 1.27 feet
15.30 inches
Therefore set crest of principal spillway at stage = 1.27 feet
and EL = 590.27 feet
• At principal spillway crest, storm pool storage provided = 23204 CF
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond#I Calculations Page 7
•
•
•
Highway 29
GYM-6040
Water Quality Siphon
Pond#1 Calculations
Siphon G =
No. siphons =
Ks =
b=
Cd siphon =
Normal Pool Elevation =
Volume @ Normal Pool =
WSEL @ 1" Runoff Volume =
Calculated WSEL increment =
2.5 inches
1
17413
1.1831
0:60
589.00 feet
0 CF
590.27 feet
0.109 feet
WSEL
(feet) Vol. Stored
c Siphon Flow
(cfs Avg. Flow
cfs) Incr. Vol.
(cf) Incr. Time
(sec)
590.275 23204 0.177
590.165 20870 0.169 0.173 2334 13489
590.056 18575 0.160 0.164 2295 13961
589.947 16324 0.150 0.155 2251 14510
589.838 14120 0.140 0.145 2204 15161
589.728 11968 0.129 0.135 2152 15952
589.619 9874 0.118 0.124 2094 16948
589.510 7847 0.104 0.111 2027 18261
589.401 5899 0.089 0.097 1948 20127
589.291 4047 0.071 0.080 1852 23137
589.182 2320 0.043 0.057 1727 30230
Conclusion : Use 1 - 2.5" Diameter Water Quality Orifice to drawdown the accumulated
volumefrom the 1.0 " stone runoff, with a required time of about 2 days.
Drawdown Time = 2.10 days
J.C. Diaz, EI
4/21/2008
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond#1 Calculations
Page 8
•
Highway 29
GWH-6040
Anti-Flotation Calculation
Pond4l Calculations
Input Data =>
Inside wall dimension of riser (1) =
Inside wall dimension of riser (2) =
Min. wall thickness of riser =
Inside height of Riser* =
Side weir/orifice area =
Concrete unit weight =
OD of barrel exiting riser =
Size of drain pipe (if present) =
Volume of Trashrack =
*Note- from riser floor to inside of top
Concrete Present =>
Total amount of concrete:
Riser Walls =
Adjust for openings:
5.0 feet
5.0 feet
6.0 inches
8.50 feet
0.03 square feet
142.0 PCF Note: NC Products lists unit
45.5 inches wt. of riser concrete at 142 PCF
8.0 inches
61.7 CF
93.50 CF
Opening for barrel= 5.65 CF
Opening for drain pipe = 0.17 CF
Opening for weirs = 0.02 CF
Total Concrete present, adjusted for openings = 87.663 CF
Weight of concrete present = 12448 lbs
•
Amount of water displaced =>
Total water displaced by riser/barrel structure = 367.700 CF
Weight of water displaced = 22944 lbs
Calculate amount of concrete to be added to riser =>
Safety factor to use = 1.15 (recommend 1. 15 or higher)
Calculate sue of base for riser assembly -
Outside Dimension (1) = 9.000 feet
Outside Dimension (2) = 9.000 feet
Thickness = 30.0 inches
Concrete Present = 202.500 CF
Check validity of base as designed =>
Total Water Displaced = 570.200 CF
Total Concrete Present = 290.163 CF
Total Water Displaced= 35580 lbs
Total Concrete Present = 41203 lbs
Actual safety factor = 1.16
•
Results of design =>
Outside Base Dimensions (rectangular) = 9.00 feet a 9.00 feet
Base Thickness = 30.00 inches
CY of concrete total in base = 7.50 CY
Concrete unit weight in added base x 142 PCF
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond#1 Calculations
J.C. Diaz, EI
4/21/2008
Page 9
0
•
•
Highway 29
GWH-6040
Outfall
Pond#1 Calculations
J.C. Diaz, El
4/21/2008
RIP RAP APRON SIZING
Based on Army Corps of Engineers Reports H-70-2 H-72-5,
and N.J. Standards for Soil Erosion and Sediment Control
ate: (1999)
Pipe Diameter, Do 36 Inches or 3 Feet
Peak Flow, Q10 47 CFS (Always use FULL FLOW)
Tailwater depth, Tw 1.5 Feet ( If Unknown, use 0.2 x Diameter in Feet )

Design: La = (1.8 x Do/Q) +7Do,
Do^0.5 If TW <Do/2, Wa = 3Do + La
Apron Length, La = 27.1 Feet Long If TW > Do/2,Wa = 3Do+ 0.41-a
Apron Width, Wa = 19.9 Feet Wide (Only if no well-defined channel downstream)
d5o Stone Size = 0.42 d5o in Feet
5.0 d50 in Inches d50 = 0.016/TW x 0,11.37
RIP RAP G RADATION PER NCDOT SPECIFICATIONS
RIP RAP MINIMUM MIDRANGE MAXIMUM
CLASS (IN.) (IN.) (IN.)
A 2 4 6
B 5 8 12
1 5 10 17
2 9 14 23
SOIL TEXTURE ALLOWABLE VELOCITY
Sand Loam 2.5 s
Silt Loam, Loam 3.0 fps
Sand Clay Loam 3.5 s
Clay Loam 4.0 fps
Clay, fine Gravel 5.0 fps
Cobbles 5.5 fps
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond#1 Calculations
Page 10
Wet Pond #1
Pondpack Version 8 Output - Outlet Rating Curve
•
•
Highway 29
GYM-06040
.0
Type.... Outlet Input Data Page 1.01
Name.... Pond 1
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
REQUESTED POND WS ELEVATIONS:
Min. Elev.= 589.00 ft
Increment = .20 ft
Max. Elev.= 596.00 ft
OUTLET CONNECTIVITY
***** * * * * * * * ************************
---> Forward Flow Only (UpStream to DnStream)
<--- Reverse Flow Only (DnStream to UpStream)
<---> Forward and Reverse Both Allowed
Structure No. Outfall E1, ft E2, ft
Inlet Box RI ---> BA 593.500 596.000
Orifice-Circular SI ---> BA 589.000 596.000
Culvert-Circular BA ---> TW 585.000 596.000
TW SETUP, DS Channel
•
•
SIN: 6217012070C3 The John R. McAdams Company
PondPack Ver. 8.0058 Time: 11:00 AM Date: 12/18/2007
Type.... Outlet Input Data Page 1.02
Name.... Pond 1
File.... X:\Projects\GWH\GWH-06040\Storm\Con struction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
• Project Comments:
OUTLET STRUCTURE INPUT DATA
Structure ID = RI
Structure Type = Inlet Box
----------------
------
--------------
# of Openings = 1
Invert Elev. = 593.50 ft
Orifice Area = 25.0000 sq.ft
Orifice Coeff. _ .600
Weir Length = 20.00 ft
Weir Coeff. = 3.000
K, Submerged = .000
K, Reverse = 1.000
Kb,Barrel = .000000 (per ft of full flow)
Barrel Length = .00 ft
Mannings n = .0000
Structure ID = Si
Structure Type = Orifice-Circular
------------------------------------
# of Openings = 1
Invert Elev. = 589.00 ft
Diameter = .2083 ft
Orifice Coeff. _ .600
•
•
SIN: 6217012070C3 The John R. McAdams Company
PondPack Ver. 8.0058 Time: 11:00 AM Date: 12/18/2007
•
•
0
Type.... Outlet Input Data Page 1.03
Name.... Pond 1
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
OUTLET STRUCTURE INPUT DATA
Structure ID = BA
Structure Type = Culvert-Circular
------------------------------------
No. Barrels = 1
Barrel Diameter = 3.0000 ft
Upstream Invert = 585.00 ft
Dnstream Invert = 584.50 ft
Horiz. Length = 78.00 ft
Barrel Length = 78.00 ft
Barrel Slope = .00641 ft/ft
OUTLET CONTROL DATA...
Mannings n = .0130
Ke = .5000 (forward entrance loss)
Kb = .007228 (per ft of full flow)
Kr = .5000 (reverse entrance loss)
HW Convergence = .001 +/- ft
INLET CONTROL DATA...
Equation form = 1
Inlet Control K = .0098
Inlet Control M = 2.0000
Inlet Control c = .03980
Inlet Control Y = .6700
Tl ratio (HW/D) = 1.157
T2 ratio (HW/D) = 1.304
Slope Factor = -.500
Use unsubmerged inlet control Form 1 equ. below T1 elev.
Use submerged inlet control Form 1 equ. above T2 elev.
In transition zone between unsubmerged and submerged inlet control,
interpolate between flows at T1 & T2...
At T1 Elev = 588.47 ft ---> Flow = 42.85 cfs
At T2 Elev = 588.91 ft ---> Flow = 48.97 cfs
SIN: 6217012070C3 The John R. McAdams Company
PondPack Ver. 8.0058 Time: 11:00 AM Date: 12/18/2007

Type.... Outlet Input Data
Name.... Pond 1
Page 1.04
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
OUTLET STRUCTURE INPUT DATA
Structure ID = TW
Structure Type = TW SETUP, DS Channel
------------------------------------
FREE OUTFALL CONDITIONS SPECIFIED
CONVERGENCE TOLERANCES ...
Maximum Iterations= 30
Min. TW tolerance = .01 ft
Max. TW tolerance = .01 ft
Min. HW tolerance = .01 ft
Max. HW tolerance = .01 ft
Min. Q tolerance = .10 cfs
Max. Q tolerance = .10 cfs
•
•
SIN: 6217012070C3 The John R. McAdams Company
PondPack Ver. 8.0058 Time: 11:00 AM Date: 12/18/2007
•
•
•
Type.... Composite Rating Curve
Name.... Pond 1
Page 1.05
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
WS Elev, Total Q
Elev. Q
ft
---- cfs
-------
----
589.00 .00
589.20 .05
589.40 .09
589.60 .12
589.80 .14
590.00 .16
590.20 .17
590.40 .19
590.60 .20
590.80 .21
591.00 .23
591.20 .24
591.40 .25
591.60 .26
591.80 .27
592.00 .28
592.20 .29
592.40 .30
592.60 .31
592.80 .32
593.00 .32
593.20 .33
593.40 .34
593.50 .34
593.60 2.24
593.80 10.21
594.00 21.58
594.20 35.51
594.40 51.61
594.60 69.54
594.80 89.13
595.00 100.21
595.20 101.46
595.40 102.69
SIN: 6217012070C3
PondPack Ver. 8.0058
***** COMPOSITE OUTFLOW SUMMARY ****
-------- Converge
TW Elev Error
ft +/-ft
-------- -----
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Notes
-------------------------
Contributing Structures
(no Q: RI,SI,BA)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
RI,SI,BA
RI,SI,BA
RI,SI,BA
RI,SI,BA
RI,SI,BA
RI,SI,BA
RI,SI,BA
RI,BA (no Q: SI)
RIBA (no Q: SI)
RI,BA (no Q: SI)
The John R. McAdams Company
Time: 11:00 AM Date: 12/18/2007
•
Type.... Composite Rating Curve
Name.... Pond 1
Page 1.06
File.... X:\Projects\GWH\GWH-06090\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
***** COMPOSITE OUTFLOW SUMMARY ****
0
•
WS Elev, Total Q Notes
-------- -------- ------ -- Converge ------ ------- ------------
Elev. Q TW El ev Error
ft
-------- cfs
------- ft
------ +/-ft
-- ----- - Contributing
------------- Structures
------------
595.60 103.90 Free Outfall RIBA (no Q: SI)
595.80 105.11 Free Outfall RIBA (no Q: SI)
596.00 106.29 Free Outfall RIBA (no Q: SI)
SIN: 6217012070C3 The John R. McAdams Company
PondPack Ver. 8.0058 Time: 11:00 AM Date: 12/18/2007
0 Wet Pond #1
Pondpack Version 8 Output - Worst Case Scenario Outlet Rating Curve
•
•
Highway 29
GWH-06040
•
Type.... Outlet Input Data Page 1.01
Name.... Pond 1 100
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
REQUESTED POND WS ELEVATIONS:
Min. Elev.= 589.00 ft
Increment = .20 ft
Max. Elev.= 596.00 ft
OUTLET CONNECTIVITY
---> Forward Flow Only (UpStream to DnStream)
<--- Reverse Flow Only (DnStream to UpStream)
<---> Forward and Reverse Both Allowed
is
•
Structure
-----------------
Inlet Box
Culvert-Circular
TW SETUP, DS Channel
SIN: 6217012070C3
PondPack Ver. 8.0058
No. Outfall E1, ft E2, ft
---- ------- --------- ---------
RI ---> BA 593.500 596.000
BA ---> TW 585.000 596.000
The John R. McAdams Company
Time: 11:01 AM Date: 12/18/2007
•
Type.... Outlet Input Data
Name.... Pond 1 100
Page 1.02
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
OUTLET STRUCTURE INPUT DATA
Structure ID = RI
Structure Type
--------------- = Inlet Box
--
# of Openings -------------
= 1 ------
Invert Elev. = 593.50 ft
orifice Area = 25.0000 sq.ft
Orifice Coeff. _ .600
Weir Length = 20.00 ft
Weir Coeff. = 3.000
K, Submerged = .000
K, Reverse = 1.000
Kb,Barrel = .000000 (per ft of full flow)
Barrel Length = .00 ft
Mannings n = .0000
•
•
SIN: 6217012070C3 The John R. McAdams Company
PondPack Ver. 8.0058 Time: 11:01 AM Date: 12/18/2007
•
•
Type.... Outlet Input Data Page 1.03
Name.... Pond 1 100
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
OUTLET STRUCTURE INPUT DATA
Structure ID = BA
Structure Type
---------------- = Culvert-Circular
--

No. Barrels -----------
= 1 -------
Barrel Diameter = 3.0000 ft
Upstream Invert = 585.00 ft
Dnstream Invert = 584.50 ft
Horiz. Length = 78.00 ft
Barrel Length = 78.00 ft
Barrel Slope = .00641 ft/ft
OUTLET CONTROL DATA...
Mannings n = .0130
Ke = .5000 (forward entrance loss)
Kb = .007228 (per ft of full flow)
Kr = .5000 (reverse entrance loss)
HW Convergence = .001 +/- ft
INLET CONTROL DATA...
Equation form = 1
Inlet Control K = .0098
Inlet Control M = 2.0000
Inlet Control c = .03980
Inlet Control Y = .6700
T1 ratio (HW/D) = 1.157
T2 ratio (HW/D) = 1.304
Slope Factor = -.500
Use unsubmerged inlet control Form 1 equ. below T1 elev.
Use submerged inlet control Form 1 equ. a bove T2 elev.
In transition zone between unsubmerged and submerged inlet control,
interpolate between flows at T1 & T2...
At T1 Elev = 588.47 ft ---> Flow = 42.85 cfs
At T2 Elev = 588.91 ft ---> Flow = 48.97 cfs
•
SIN: 6217012070C3
PondPack Ver. 8.0058
The John R. McAdams Company
Time: 11:01 AM
Date: 12/18/2007
•
•
•
Type.... Composite Rating Curve
Name.... Pond 1 100
Page 1.04
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
***** COMPOSITE OUTFLOW SUMMARY ****
CUMULATIVE HGL CONVERGENCE ERROR .000 (+/- ft)
WS Elev, Total Q Notes
---------------- -------- Converge
-------------------------
Elev. Q TW Elev Error
ft cfs ft +/-ft Contributing Structures
-------- ------- -------- ----- --------------------------
589.00 .00 590.70 .000 (no Q: RI,BA)
589.20 .00 590.70 .000 (no Q: RIBA)
589.40 .00 590.70 .000 (no Q: RI,BA)
589.60 .00 590.70 .000 (no Q: RIBA)
589.80 .00 590.70 .000 (no Q: RIBA)
590.00 .00 590.70 .000 (no Q: RIBA)
590.20 .00 590.70 .000 (no Q: RIBA)
590.40 .00 590.70 .000 (no Q: RIBA)
590.60 .00 590.70 .000 (no Q: RIBA)
590.80 .00 590.70 .000 (no Q: RIBA)
591.00 .00 590.70 .000 (no Q: RIBA)
591.20 .00 590.70 .000 (no Q: RIBA)
591.40 .00 590.70 .000 (no Q: RI,BA)
591.60 .00 590.70 .000 (no Q: RIBA)
591.80 .00 590.70 .000 (no Q: RIBA)
592.00 .00 590.70 .000 (no Q: RI,BA)
592.20 .00 590.70 .000 (no Q: RIBA)
592.40 .00 590.70 .000 (no Q: RIBA)
592.60 .00 590.70 .000 (no Q: RIBA)
592.80 .00 590.70 .000 (no Q: RIBA)
593.00 .00 590.70 .000 (no Q: RIBA)
593.20 .00 590.70 .000 (no Q: RI,BA)
593.40 .00 590.70 .000 (no Q: RIBA)
593.50 .00 590.70 .000 (no Q: RIBA)
593.60 1.90 590.70 .000 RIBA
593.80 9.86 590.70 .000 RIBA
594.00 21.21 590.70 .000 RIBA
594.20 35.14 590.70 .000 RIBA
594.40 51.23 590.70 .000 RI,BA
594.60 77.95 590.70 .000 RIBA
594.80 79.92 590.70 .000 RIBA
595.00 81.85 590.70 .000 RIBA
SIN: 6217012070C3
PondPack Ver. 8.0058
The John R. McAdams Company
Time: 11:01 AM
Date: 12/18/2007
Type.... Composite Rating Curve
Name.... Pond 1 100
•
•
•
Page 1.05
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
***** COMPOSITE OUTFLOW SUMMARY ****
CUMULATIVE HGL CONVERGENCE ERROR .000 (+/- ft)
WS Elev, Total Q Notes
---------------- -------- Converge
-------------------------
Elev. Q TW Elev Error
ft cfs ft +/-ft Contributing Structures
-------- ------- -------- ----- --------------------------
595.20 83.72 590.70 .000 RIBA
595.40 85.56 590.70 .000 RIBA
595.60 87.36 590.70 .000 RIBA
595.80 89.13 590.70 .000 RIBA
596.00 90.87 590.70 .000 RIBA
SIN: 6217012070C3 The John R. McAdams Company
PondPack Ver. 8.0058 Time: 11:01 AM Date: 12/18/2007
S Wet Pond #2 Design
•
Contents
Above Normal Pool Stage-Storage Function
Below Normal Pool Stage-Storage Function
Forebay Stage-Storage Function
Surface Area Calculations
Water Quality Volume Calculations
Drawdown Calculations
Anti-Float Calculations
Energy Dissipater Calculations
• Pondpack Version 8 Output
Highway 29
GWH-06040
Highway 29 Above NWSE J.C. Diaz, El
GWH-6040 Pond#2 Caks 12/17/2007
• Average Incremental Accumulated Estimated
Contour Contour Contour Contour Stage
Contour Stage Area Area Volume Volume w/ S-S Fxn
(feet) (feet) (SF) (SF) (CF) (CF) (feet)
604.0 0.0 12853
605.0 1.0 14238 13 546 13 546 13 546 1.02
606.0 2.0 15680 14959 14959 28505 1.97
607.0 3.0 17178 16429 16429 44934 2.94
608.0 4.0 18733 17956 17956 62889 3.95
609.0 5.0 20344 19539 19539 82428 5.02
610.0 6.0 22012 21178 21178 103606 6.14
•
Storage vs. Stage
120000
100000 y = 13241x 1.1332
LL 80000 R2 = 0.9992
U
as 60000
0
40000
20000
0
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0
Stage (feet)
Ks = 13241
b = 1.1332
•
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond#2 Calcs
Page 1
•
•
•
Highway 29 S-S Function
GWH-6040 Pond#2 Calculations
Stage - Storage Function
Ks= 13241
b= 1.1332
Zo = 604.00
Elevation Stora a Worst Case Scenario Storage
[feet] [cf] [acre-feet] [acre-feet]
604.00 0 0.000 -
604.20 2137 0.049 -
604.40 4688 0.108 -
604.60 7422 0.170 -
604.80 10283 0.236 -
605.00 13241 0.304 -
605.20 16280 0.374 -
605.40 19387 0.445 -
605.60 22554 0.518 -
605.80 25775 0.592 -
606.00 29043 0.667 0.000
606.20 32356 0.743 0.076
606.40 35709 0.820 0.153
606.60 39099 0.898 0.231
606.80 42525 0.976 0.309
607.00 45983 1.056 0.389
607.20 49472 1.136 0.469
607.40 52990 1.216 0.550
607.60 56536 1.298 0.631
607.80 60108 1.380 0.713
608.00 63705 1.462 0.796
608.20 67327 1.546 0.879
608.40 70971 1.629 0.963
608.60 74638 1.713 1.047
608.80 78326 1.798 1.131
609.00 82034 1.883 1.216
609.20 85762 1.969 1.302
609.40 89510 2.055 1.388
609.60 93275 2.141 1.475
609.80 97059 2.228 1.561
610.00 100861 2.315 1.649
X:\Projects\GW14\GWH-06040\Storm\Construction Drawings\Design Files\Pond#2 Calculations
J.C. Diaz, El
12/18/2007
Page I
Highway 29 Below NWSE J.C. Diaz, El
GWH-6040 Pond#2 Calcs 12/17/2007
• Average Incremental Accumulated Estimated
Contour Contour Contour Contour Stage
Contour Stage Area Area Volume Volume w/ S-S Fxn
(feet) (feet) (SF) (SF) (CF) (CF) (feet)
599.0 0.0 4259
600.0 1.0 5317 4788 4788 4788 1.03
601.0 2.0 6515 5916 5916 10704 1.94
602.0 3.0 7776 7146 7146 17850 2.89
603.0 4.0 10064 8920 8920 26770 3.97
604.0 5.0 12853 11459 11459 38228 5.24
•
Storage vs. Stage
45000
40000
35000 y = 4598.5x1.2785
30000
m 25000 R2 = 0.9964
20000
0
15000
10000
5000--
0
0.0 1.0 2.0 3.0 4.0 5.0 6.0
Stage (feet)
Ks = 4598.5
b = 1.2785
•
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond#2 Calcs Page 3
Highway 29
GWH-6040
•
•
Forebay 1 J.C. Diaz, El
Pond#2 Calcs 12/17/2007
Average Incremental Accumulated Estimated
Contour Contour Contour Contour Stage
Contour Stage Area Area Volume Volume w/ S-S Fxn
(feet) (feet) (SF) (SF) (CF) (CF) (feet)
599.0 0.0 231
600.0 1.0 364 298 298 298 1.02
601.0 2.0 523 444 444 741 1.94
602.0 3.0 707 615 615 1356 2.96
603.0 4.0 915 811 811 2167 4.11
Storage vs. Stage
2500-
2000-- y = 289.41x 1424
R2 = 0.9978
LL 1500
m
0 1000
500
0
0.0 1.0 2.0 3.0 4.0 5.0
Stage (feet)
Ks = 289.41
b = 1.424
0
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond#2 Calcs
Page 4
Highway 29
GWH-6040
•
0
Forebay 2
Pond#2 Calcs
J.C. Diaz, El
12/17/2007

Contour
(feet)

Stage
(feet)
Contour
Area
(SF) Average
Contour
Area
(SF) Incremental
Contour
Volume
(CF) Accumulated
Contour
Volume
(CF) Estimated
Stage
w/ S-S Fxn
(feet)

599.0 0.0 1033
600.0 1.0 1384 1209 1209 1209 1.02
601.0 2.0 1826 1605 1605 2814 1.95
602.0 3.0 2281 2054 2054 4867 2.97
603.0 4.0 2764 2523 2523 7390 4.09
Storage vs. Stage
8000
7000 y = 1183.8x1.3
6000R2 = 0.9985
V 5000
4000
3000
2000
1000
0
0.0 1.0 2.0 3.0 4.0 5.0
Stage (feet)
Ks = 1183.8
b = 1.3
•
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond#2 Calcs
Page 5
Highway 29 Forebay and Surface Area J.C. Diaz, El
GWH-6040 Pond#2 Calcs 12/17/2007
,1?VOyLUyIL?CHIi?C,I ?? Per NCDENR Stormwater Best Management Practices ", the forebay volume should equal about 20% of the total
basin volume.
A. Water Quality Pond - Below Normal Pool
NWSE= 604
Stage - Storage Function
Ks = 4598.5
b= 1.2785
Zo = 599
Volume = 35996 ft3
B. Forebay Volume
Forebay 1: Volume
Stage - Storage Function
Ks = 289.41
b= 1.424
Zo = 599
Volume = 2084 ft3
Forebay 1: Volume
Stage - Storage Function
Ks = 1183.8
b= 1.3
Zo = 599
• Volume = 7177 ft3

%Foreba = 25.7%
1.1 SURFACE AREA CHECK ' ,
Impervious Area= 7.18 acres
Drainage Area = 12.00 acres
% Impervious = 60%
Average Depth = Accumulated Contour Volume / Surface Area
ACV = 38228 cf
SA = 12853 sf
Average Depth = 3.0 ft.
From the Greensboro Stormwater Handbook, the required SA/DA ratio =>
3.0 3.0 4.0
Lower Boundary => 50.0 2.06 1.73
Site % impervious => 59.8 2.39 2.40 2.03
Upper Boundary => 60.0 2.40 2.03
Area Required = 12565 sq.ft.
Area Provided = 12853 s .ft.
•
X:\Projects\GWMGWH-06040\Storm\Construction Drawings\Design Files\Pond#2 Calcs Page 6
Highway 29 Water OualitV Volume J.C. Diaz, EI
GWH-6040 Pond#2 Calcs 12/17/2007
1s = 13241
• b = 1.1332
Calculation of Runoff Volume required for storage
The runoff to the pond for the 1" storm detention requirement is calculated using the SCS curve
number method. Impervious areas that directly enter the pond are counted as Directly Connected
Impervious Areas (DCIAs). No infiltration calculation will be provided for these areas. Areas
not directly connected will be accounted for in a composite curve number.
Using basic SCS runoff methodology, with no adjus
to initial abstractions (0.2*S and 0.8*S).
Impervious Area, directly connected (DCIA) _
@CN=
Other areas draining to pond (not DCIA) =
@CN=
tments made
7.18 acres
98
4.82 acres
74
Runoff from DCIAs =>
Precipitation amount = 1.0 inches
S = 0.204 inches (calculated)
Q* = 0.791 inches (calculated)
Runoff volume = 20614 CF
• Runoff from non-connected areas -
Precipitation amount = 1.0 inches
S = 3.514 inches (calculated)
Q* = 0.023 inches (calculated)
Runoff volume= 406 CF
Therefore, total runoff from precipitation in question = 21020 CF
This amount of runoff must be stored in the pond above normal pool elevation,
and be released in a period of two (2) to five (5) days, by an inverted PVC
siphon, the invert end of which is set at permanent pool elevation.
Calculation of depth required for runoff storage pool (above normal pooQ
Normal pool depth (above invert) = 0.00 feet
Storage provided at permanent pool depth = 0 CF (calculated)
Total storage required for normal + storage pool = 21020 CF
Stage (above invert) associated with this storage = 1.50 feet
1 Therefore, depth required above normal pool for storm storage = 1.50 feet
18.04 inches
Therefore set crest of principal spillway at stage = 1.50 feet
and EL = 605.50 feet
• At principal spillway crest, storm pool storage provided = 21020 CF
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Filcs\Pond#2 Calcs Page 7
•
•
Highway 29
GWH-6040
Water Quality Siphon
Pond#2 Calcs
Siphon G =
No. siphons =
Ks =
b=
Cd siphon =
Normal Pool Elevation =
Volume @ Normal Pool =
WSEL @ V Runoff Volume =
Calculated WSEL increment =
2 inches
1
13241
1.1332
0.60
604.00 feet
0 CF
605.50 feet
0.131 feet
WSEL
(feet) Vol. Stored
(cf) Siphon Flow
(cfs Avg. Flow
(cfs) Incr. Vol.
(c Incr. Time
(sec)
605.504 21020 0.125
605.373 18962 0.119 0.122 2057 16858
605.242 16931 0.113 0.116 2031 17512
605.112 14927 0.106 0.110 2003 18272
604.981 12956 0.099 0.103 1972 19172
604.850 11018 0.092 0.096 1937 20262
604.720 9120 0.084 0.088 1898 21626
604.589 7268 0.075 0.079 1852 23410
604.458 5470 0.064 0.069 1798 25904
604.328 3740 0.052 0.058 1730 29809
604.197 2102 0.035 0.044 1638 37567
Drawdown Time = 2.67 days J.C. Diaz, El
12/17/2007
Conclusion : Use 1 - 2.0" Diameter Water Quality Orifice to drawdown the accumulated
volume from the 1.0 " storm runoff, with a required time of about 2 days.
•
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond#2 Calcs
Page 8
Highway 29 Anti-Flotation Calculation J.C. Diaz, El
GWH-6040 Pond#2 Calculations 12/18/2007
•
Input Data =>
Inside wall dimension of riser (1) _
Inside wall dimension of riser (2) _
Min. wall thickness of riser =
Inside height of Riser* _
Side weir area =
Concrete unit weight =
OD of barrel exiting riser =
Size of drain pipe (if present) _
Volume of Trashrack =
*Note- from riser floor to inside of top
Concrete Present =>
Total amount of concrete:
Adjust for openings:
5.0 feet
5.0 feet
6.0 inches
9.50 feet
0.81 square feet
142.0 PCF Note: NC Products lists unit
45.5 inches wt. of riser concrete at 142 PCF
8.0 inches
61.7 CF
Riser Walls = 104.50 CF
Opening for barrel = 5.65 CF
Opening for drain pipe = 0.17 CF
Opening for weirs = 0.40 CF
Total Concrete present, adjusted for openings= 98.276 CF
Weight of concrete present = 13955 lbs
•
Amount of water displaced =>
Total water displaced by riser/barrel structure = 403.740 CF
Weight of water displaced = 25193 Ibs
Calculate amount of concrete to be added to riser =>
Safety factor to use = 1.15 (recommend 1.15 or higher)
Calculate size of base for riser assembly =>
Outside Dimension (1) = 9.000 feet
Outside Dimension (2) = 9.000 feet
Thickness= 33.0 inches
Concrete Present = 222.750 CF
Check validity of base as designed -
Total Water Displaced = 626.490 CF
Total Concrete Present = 321.026 CF
Total Water Displaced = 39093 lbs
Total Concrete Present = 45586 Ibs
Actual safety factor = 1.17
•
Results of design =>
Outside Base Dimensions (rectangular) = 9.00 feet a 9.00 feet
Base Thickness = 33.00 inches
CY of concrete total in base = 8.25 CY
Concrete unit weight in added base >= 142 PCF
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond#2 Calculations
Page 9
Highway 29 Outfall J.C. Diaz, EI
GWH-6040 Pond#2 Calculations 12/18/2007
•
•
RIP RAP APRON SIZING
Based on Arty Corps of Engineers Reports H-70-2 H-72-5,
and N.J. Standards for Soil Erosion and Sediment Control
(1999)
Input:
Pipe Diameter, Do 36 Inches or 3 Feet
Peak Flow, Qto 47 CFS (Always use FULL FLOW)
Tailwater depth, Tw 1.5 Feet ( If Unknown, use 0.2 x Diameter in Feet )

Desi
Apron Length, La = La= (1.8 x Do/Q) +7Do,
Do/10.5 If TW <Do/2, Wa = 3Do + La
27.1 Feet Long If TW > Do/2,Wa = 3Do+ 0.4
Apron Width, Wa = 19.9 Feet Wide (Only if no well-defined channel downstream )
d5o Stone Size = 0.42 d5o in Feet
5.0 d5o in Inches d5o = 0.016/TW x (g)1'33
RIP RAP GRADATION PER NCDOT SPECIFICATIONS
RIP RAP MINIMUM MIDRANGE MAXIMUM
CLASS (IN) (IN.) (IN.)
A 2 4 6
B 5 8 12
1 5 10 17
2 9 14 23
•
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond#2 Calculations
SOIL TEXTURE ALLOWABLE VELOCITY
Sand Loam 2.5 s
Silt Loam, Loam 3.0 fps
Sand Clay Loam 3.5 s
Clay Loam 4.0 fps
Clay, fine Gravel 5.0 fps
Cobbles 5.5 fps
Page 10
• Wet Pond #2
Pondpack Version 8 Output - Outlet Rating Curve
•
•
Highway 29
GWH-06040
•
Type.... Outlet Input Data Page 1.01
Name.... Pond 2
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
REQUESTED.POND WS ELEVATIONS:
Min. Elev.= 604.00 ft
Increment = .20 ft
Max. Elev.= 610.00 ft
OUTLET CONNECTIVITY
---> Forward Flow Only (Upstream to DnStream)
<--- Reverse Flow Only (DnStream to Upstream)
<---> Forward and Reverse Both Allowed
Structure No. Outfall E1, ft E2, ft
----------------- ---- ------- --------- ---------
Orifice-Circular OR ---> BA 606.000 610.000
Inlet Box RI ---> BA 608.500 610.000
Orifice-Circular SI ---> BA 604.000 610.000
Culvert-Circular BA ---> TW 599.000 610.000
TW SETUP, DS Channel
•
•
SIN: 6217012070C3 The John R. McAdams Company
PondPack Ver. 8.0058 Time: 10:04 AM Date: 12/19/2007
•
Type.... Outlet Input Data
Name.... Pond 2
Page 1.02
File.... X:\Projects\GWH\GWH-06090\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
OUTLET STRUCTURE INPUT DATA
Structure ID = OR
Structure Type = Orifice-Circular
------------------------------------
# of Openings = 1
Invert Elev. = 606.00 ft
Diameter = 1.0000 ft
orifice Coeff. _ .600
Structure ID = RI
Structure Type
----- = Inlet Box
-------------
------
------------
# of Openings = 1
Invert Elev. = 608.50 ft
orifice Area = 25.0000 sq.ft
orifice Coeff. _ .600
Weir Length = 20.00 ft
Weir Coeff. = 3.000
K, Submerged = .000
K, Reverse = 1.000
Kb,Barrel = .000000 (per ft of full flow)
Barrel Length = .00 ft
Mannings n = .0000
•
•
Structure ID = SI
Structure Type = Orifice-Circular
------------------------------------
# of Openings = 1
Invert Elev. = 604.00 ft
Diameter = 1667 It
Orifice Coeff. _ .600
SIN: 6217012070C3 The John R. McAdams Company
PondPack Ver. 8.0058 Time: 10:04 AM Date: 12/19/2007
•
Type.... Outlet Input Data
Name.... Pond 2
Page 1.03
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
OUTLET STRUCTURE INPUT DATA
Structure ID = BA
Structure Type
--- = Culvert-Ci
------------ rcular
------
---------------
No. Barrels = 1
Barrel Diameter = 3.0000 ft
Upstream Invert = 599.00 ft
Dnstream Invert = 598.50 ft
Horiz. Length = 68.00 ft
Barrel Length = 68.00 ft
Barrel Slope = .00735 ft/ft
OUTLET CONTROL DATA...
Mannings n = .0130
Ke = .5000
Kb = .007228
Kr = 5000
HW Convergence = .001
(forward entrance loss)
(per ft of full flow)
(reverse entrance loss)
+/- ft
INLET CONTROL DATA...
Equation form = 1
Inlet Control K = .0098
Inlet Control M = 2.0000
Inlet Control c = .03980
Inlet Control Y = .6700
T1 ratio (HW/D) = 1.157
T2 ratio (HW/D) = 1.303
Slope Factor _ -.500
•
•
Use unsubmerged inlet control Form 1 equ. below T1 elev.
Use submerged inlet control Form 1 equ. above T2 elev.
In transition zone between unsubmerged and submerged inlet control,
interpolate between flows at T1 & T2...
At Tl Elev = 602.47 ft ---> Flow = 42.85 cfs
At T2 Elev = 602.91 ft ---> Flow = 48.97 cfs
SIN: 6217012070C3 The John R. McAdams Company
PondPack Ver. 8.0058 Time: 10:04 AM Date: 12/19/2007
•
Type.... Outlet Input Data
Name.... Pond 2
Page 1.04
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
OUTLET STRUCTURE INPUT DATA
Structure ID = TW
Structure Type = TW SETUP, DS Channel
------------------------------------
FREE OUTFALL CONDITIONS SPECIFIED
CONVERGENCE TOLERANCES ...
Maximum Iterations= 30
Min. TW tolerance = .01 ft
Max. TW tolerance = .01 ft
Min. HW tolerance = .01 ft
Max. HW tolerance = .01 ft
Min. Q tolerance = .10 cfs
Max. Q tolerance = .10 cfs
•
•
SIN: 6217012070C3 The John R. McAdams Company
PondPack Ver. 8.0058 Time: 10:04 AM Date: 12/19/2007
•
•
•
Type.... Composite Rating Curve
Name.... Pond 2
Page 1.05
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 2 9
Project Comments:
**** * COM POSITE OUTFL OW SUMMARY *** *
WS Elev, Total Q Notes
-------- -------- - ----- -- Converge -------------- -----------
Elev. Q TW El ev Error
ft cfs ft +/-ft
----- - Contributing S
-------------- tructures
----------
--------
604.00 ------- -
.00 -----
Free --
Outfall (no Q: OR,RI, SI,BA)
604.20 .04 Free Outfall SI,BA (no Q: OR,RI)
604.40 .06 Free Outfall SI,BA (no Q: OR,RI)
604.60 .08 Free Outfall SI,BA (no Q: OR,RI)
604.80 .09 Free Outfall SI,BA (no Q: OR,RI)
605.00 .10 Free Outfall SI,BA (no Q: OR,RI)
605.20 .11 Free Outfall SI,BA (no Q: OR,RI)
605.40 .12 Free Outfall SI,BA (no Q: OR,RI)
605.60 .13 Free Outfall SI,BA (no Q: OR,RI)
605.80 .14 Free Outfall SI,BA (no Q: OR,RI)
606.00 .15 Free Outfall SI,BA (no Q: OR,RI)
606.20 .29 Free Outfall OR,SI,BA (no Q: RI)
606.40 .66 Free Outfall OR,SI,BA (no Q: RI)
606.60 1.24 Free Outfall OR,SI,BA (no Q: RI)
606.80 1.95 Free Outfall OR,SI,BA (no Q: RI)
607.00 2.85 Free Outfall OR,SI,BA (no Q: RI)
607.20 3.35 Free Outfall OR,SI,BA (no Q: RI)
607.40 3.78 Free Outfall OR,SI,BA (no Q: RI)
607.60 4.16 Free Outfall OR,SI,BA (no Q: RI)
607.80 4.51 Free Outfall OR,SI,BA (no Q: RI)
608.00 4.84 Free Outfall OR,SI,BA (no Q: RI)
608.20 5.14 Free Outfall OR,SI,BA (no Q: RI)
608.40 5.43 Free Outfall OR,SI,BA (no Q: RI)
608.50 5.57 Free Outfall OR,SI,BA (no Q: RI)
608.60 7.60 Free Outfall OR,RI,SI,BA
608.80 15.82 Free Outfall OR,RI,SI,BA
609.00 27.42 Free Outfall OR,RI,SI,BA
609.20 41.59 Free Outfall OR,RI,SI,BA
609.40 57.91 Free Outfall OR,RI,SI,BA
609.60 76.08 Free Outfall OR,RI,SI,BA
609.80 94.08 Free Outfall OR,RI,SI,BA
610.00 106.30 Free Outfall RIBA (no Q: OR,SI)
SIN: 6217012070C3 The John R. McAdams Company
PondPack Ver. 8.0058 Time: 10:04 AM Date: 12/19/2007
0 Wet Pond #2
Pondpack Version 8 Output - Worst Case Scenario Outlet Rating Curve
•
•
Highway 29
GYM-06040
•
Type.... Outlet Input Data Page 1.01
Name.... Pond 2 100
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
REQUESTED POND WS ELEVATIONS:
Min. Elev.= 605.00 ft
Increment = .20 ft
Max. Elev.= 610.00 ft
OUTLET CONNECTIVITY
---> Forward Flow Only (UpStream to DnStream)
<--- Reverse Flow Only (DnStream to UpStream)
<---> Forward and Reverse Both Allowed
•
•
Structure
Inlet Box
Orifice-Circular
Culvert-Circular
TW SETUP, DS Channel
SIN: 6217012070C3
PondPack Ver. 8.0058
No. Outfall
---- E1, ft
--------- E2, ft
---------
----
RI ---
---> BA 608.500 610.000
OR ---> BA 606.000 610.000
BA ---> TW 599.000 610.000
The John R. McAdams Company
Time: 10:05 AM Date: 12/19/2007
•
Type.... Outlet Input Data
Name.... Pond 2 100
Page 1.02
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
OUTLET STRUCTURE INPUT DATA
Structure ID = RI
Structure Type
---- = Inlet Box
-------------
------
-------------
# of Openings = 1
Invert Elev. = 608.50 ft
orifice Area = 25.0000 sq.ft
orifice Coeff. _ .600
Weir Length = 20.00 ft
Weir Coeff. = 3.000
K, Submerged = .000
K, Reverse = 1.000
Kb,Barrel = .000000 (per ft of full flow)
Barrel Length = .00 ft
Mannings n = .0000
Structure ID = OR
Structure Type = Orifice-Circular
------------------------------------
# of Openings = 1
Invert Elev. = 606.00 ft
Diameter = 1.0000 ft
orifice Coeff. _ .600
•
•
SIN: 6217012070C3 The John R. McAdams Company
PondPack Ver. 8.0058 Time: 10:05 AM Date: 12/19/2007
•
Type.... Outlet Input Data
Name.... Pond 2 100
Page 1.03
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
OUTLET STRUCTURE INPUT DATA
Structure ID = BA
Structure Type
- = Culvert-Circular
-------------------
----------------
No. Barrels = 1
Barrel Diameter = 3.0000 ft
Upstream Invert = 599.00 ft
Dnstream Invert = 598.50 ft
Horiz. Length = 68.00 ft
Barrel Length = 68.00 ft
Barrel Slope = .00735 ft/ft
OUTLET CONTROL DATA...
Mannings n = .0130
Ke = .5000
Kb = .007228
Kr = .5000
HW Convergence = .001
(forward entrance loss)
(per ft of full flow)
(reverse entrance loss)
+/- ft
INLET CONTROL DATA...
Equation form = 1
Inlet Control K = .0098
Inlet Control M = 2.0000
Inlet Control c = .03980
Inlet Control Y = .6700
T1 ratio (HW/D) = 1.157
T2 ratio (HW/D) = 1.303
Slope Factor = -.500
0
•
Use unsubmerged inlet control Form 1 equ. below T1 elev.
Use submerged inlet control Form 1 equ. above T2 elev.
In transition zone between unsubmerged and submerged inlet control,
interpolate between flows at T1 & T2...
At T1 Elev = 602.47 ft ---> Flow = 42.85 cfs
At T2 Elev = 602.91 ft ---> Flow = 48.97 cfs
SIN: 6217012070C3 The John R. McAdams Company
PondPack Ver. 8.0058 Time: 10:05 AM Date: 12/19/2007
•
•
•
Type.... Composite Rating Curve
Name.... Pond 2 100
Page 1.04
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
***** COMPOSITE OUTFLOW SUMMARY ****
CUMULATIVE HGL CONVERGENCE ERROR .002 (+/- ft)
FLOW PATH: Elev= 609.6; Branch: OR-BA-TW
* Max. convergence errors shown may also occur for
flow paths other than the ones listed above.
WS Elev, Total Q Notes
---------------- -------- Converge -------------------------
Elev. Q TW Elev Error
ft cfs ft +/-ft Contributing Structures
-------- ------- -------- ----- --------------------------
605.00 .00 603.13 .000 (no Q: RI,OR,BA)
605.20 .00 603.13 .000 (no Q: RI,OR,BA)
605.40 .00 603.13 .000 (no Q: RI,OR,BA)
605.60 .00 603.13 .000 (no Q: RI,OR,BA)
605.80 .00 603.13 .000 (no Q: RI,OR,BA)
606.00 .00 603.13 .000 (no Q: RI,OR,BA)
606.20 .13 603.13 .000 OR,BA (no Q: RI)
606.40 .50 603.13 .000 OR,BA (no Q: RI)
606.60 1.07 603.13 .000 OR,BA (no Q: RI)
606.80 1.78 603.13 .000 OR,BA (no Q: RI)
607.00 2.67 603.13 .000 OR,BA (no Q: RI)
607.20 3.16 603.13 .000 OR,BA (no Q: RI)
607.40 3.59 603.13 .000 OR,BA (no Q: RI)
607.60 3.96 603.13 .000 OR,BA (no Q: RI)
607.80 4.31 603.13 .000 OR,BA (no Q: RI)
608.00 4.63 603.13 .000 OR,BA (no Q: RI)
608.20 4.93 603.13 .000 OR,BA (no Q: RI)
608.40 5.21 603.13 .000 OR,BA (no Q: RI)
608.50 5.35 603.13 .000 OR,BA (no Q: RI)
608.60 7.37 603.13 .000 RI,OR,BA
608.80 15.59 603.13 .000 RI,OR,BA
609.00 27.19 603.13 .000 RI,OR,BA
609.20 41.35 603.13 .000 RI,OR,BA
609.40 57.67 603.13 .000 RI,OR,BA
609.60 75.68 603.13 .002 RI,OR,BA
609.80 93.22 603.13 .000 RIBA (no Q: OR)
610.00 105.31 603.13 .000 RIBA (no Q: OR)
SIN: 6217012070C3 The John R. McAdams Company
PondPack Ver. 8.0058 Time: 10:05 AM Date: 12/19/2007
•

Wet Pond #3 Design
Contents
•
Above Normal Pool Stage-Storage Function
Below Normal Pool Stage-Storage Function
Forebay Stage-Storage Function
Surface Area Calculations
Water Quality Volume Calculations
Drawdown Calculations
Anti-Float Calculations
Energy Dissipater Calculations
Pondpack Version 8 Output
Highway 29
GVM-06040
Highway 29 Above NWSE J.C. Diaz, El
GWH-6040 Pond-43 Calcs 12/17/2007
• Average Incremental Accumulated Estimated
Contour Contour Contour Contour Stage
Contour Stage Area Area Volume Volume w/ S-S Fxn
(feet) (feet) (SF) (SF) (CF) (CF) (feet)
604.0 0.0 7216
605.0 1.0 8274 7745 7745 7745 1.01
606.0 2.0 9388 8831 8831 16576 1.97
607.0 3.0 10560 9974 9974 26550 2.98
608.0 4.0 11787 11174 11174 37724 4.05
•
Storage vs. Stage
40000
35000 Y = 7663.5x1.1386
30000 R2 = 0.9995
V 25000
20000
N 15000
10000
5000
0
0.0 1.0 2.0 3.0 4.0 5.0
Stage (feet)
Ks = 7663.5
b = 1.1386
0
X:\Projects\GWHIGWH-06040\Storm\Construction Drawings\Design Files\Pond#3 Calcs Page 1
Highway 29 S-S Function J.C. Diaz, EI
GWH-6040 Pond#3 Calcs 12/17/2007
•
•
•
Stage - Storage Function
Ks = 7663.5
b = 1.1386
Zo = 604.00
Elevation Stora a Worst Case Scenario Storage
[feet] [cf] [acre-feet] [acre-feet]
604.00 0 0.000 -
604.20 1226 0.028 -
604.40 2700 0.062 -
604.60 4284 0.098 -
604.80 5944 0.136 -
605.00 7664 0.176 -
605.20 9432 0.217 -
605.40 11241 0.258 -
605.60 13087 0.300 -
605.80 14965 0.344 -
606.00 16873 0.387 -
606.20 18807 0.432 -
606.40 20765 0.477 -
606.60 22747 0.522 0.023
606.80 24749 0.568 0.069
607.00 26772 0.615 0.115
607.20 28813 0.661 0.162
607.40 30872 0.709 0.209
607.60 32948 0.756 0.257
607.80 35040 0.804 0.305
608.00 37148 0.853 0.353
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond#3 Calcs
Page 2
Highway 29 Below NWSE J.C. Diaz, El
GWH-6040 Pond#3 Calcs 12/17/2007
Average Incremental Accumulated Estimated
Contour Contour Contour Contour Stage
Contour Stage Area Area Volume Volume w/ S-S Fxn
(feet) (feet) (SF) (SF) (CF) (CF) (feet)
598.0 0.0 1309
599.0 1.0 2145 1727 1727 1727 1.04
600.0 2.0 2659 2402 2402 4129 1.95
601.0 3.0 3246 2953 2953 7082 2.87
602.0 4.0 3918 3582 3582 10664 3.85
603.0 5.0 5530 4724 4724 15388 5.00
604.0 6.0 7216 6373 6373 21761 6.42
•
Storage vs. Stage
25000
20000 13947
y = 1628.6x
15000 R2 = 0.9953
d
0 10000
5000
0
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0
Stage (feet)
Ks = 1628.6
b = 1.3947
•
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond#3 Calcs
Page 3
Highway 29 Forebay 1 J.C. Diaz, El
GWH-6040 Pond#3 Calcs 12/17/2007
• Average Incremental Accumulated Estimated
Contour Contour Contour Contour Stage
Contour Stage Area Area Volume Volume w/ S-S Fxn
(feet) (feet) (SF) (SF) (CF) (CF) (feet)
599.0 0.0 501
600.0 1.0 691 596 596 596 1.02
601.0 2.0 907 799 799 1395 1.94
602.0 3.0 1148 1028 1028 2423 2.96
603.0 4.0 1414 1281 1281 3704 4.10
•
Storage vs. Stage
4000
3500 y = 583.23x1.3109
3000 R2 = 0.9984
V 2500
m 2000
N 1500
1000
500
0
0.0 1.0 2.0 3.0 4.0 5.0
Stage (feet)
Ks = 583.23
b = 1.3109
0
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond43 Calcs Page 4
Highway 29 Forebay and Surface Area J.C. Diaz, El
GWH-6040 Pond#3 Calcs 12/17/2007
j .1 T Bmm E M`LHE? K r.,F,
Per NCDENR "Stormwater Best Management Practices ", the forebay volume should equal about 20% of the total
basin volume.
A. Water Quality Pond - Below Normal Pool
NWSE = 604
Stage - Storage Function
Ks = 1628.6
b= 1.3947
Zo = 598
Volume = 19820 ft3
B. Forebay Volume
Forebay 1: Volume
Stage - Storage Function
Ks = 583.23
b= 1.3109
Zo = 599
Volume = 3590 ft3

• % Foreba = 18.1%

IL SLIRI;:?CE AREA'C lIECK
Impervious Area = 1.44 acres
Drainage Area = 2.48 acres
% Impervious = 58%
Average Depth = Accumulated Contour Volume / Surface Area
ACV = 21761 cf
SA = 7216 sf
Average Depth = 3.0 ft.
From the Greensboro Stormwater Handbook, the required SA/DA ratio ==>
3.0 3.0 4.0
Lower Boundary => 50.0 2.06 1.73
Site % impervious => 58.1 2.33 Z33 1.97
Upper Boundary => 60.0 2.40 2.03
Area Required = 2516 sq.ft.

• Area Provided = 7216 s .ft.
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond43 Calcs Page 5
Highway 29 Water Ouality Volume J.C. Diaz, El
GWH-6040 Pond#3 Calcs 12/17/2007
• Ks = 7663.5
b = 1.1386
Calculation of Runoff Volume required for storage
The runoff to the pond for the 1" storm detention requirement is calculated using the SCS curve
number method. Impervious areas that directly enter the pond are counted as Directly Connected
Impervious Areas (DCIAs). No infiltration calculation will be provided for these areas. Areas
not directly connected will be accounted for in a composite curve number.
Using basic SCS runoff methodology, with no adju:
to initial abstractions (0.2*S and 0.8*S).
Impervious Area, directly connected (DCIA) _
@CN=
Other areas draining to pond (not DCIA) =
@CN=
xments made
1.44 acres
98
1.04 acres
74
Runoff from DCIAs
Precipitation amount = 1.0 inches
S = 0.204 inches (calculated)
Q* = 0.791 inches (calculated)
Runoff volume = 4134 CF
• Runoff from non-connected areas
=y
Precipitation amount = 1.0 inches
S = 3.514 inches (calculated)
Q* = 0.023 inches (calculated)
Runoff volume = 88 CF
Therefore, total runoff from precipitation in question = 4222 CF
This amount of runoffmust be stored in the pond above normal pool elevation,
and be released in a period of two (2) to five (5) days, by an inverted PVC
siphon, the invert end of which is set at permanent pool elevation.
Calculation of depth required for runoff storage pool (above normal pool)
Normal pool depth (above invert) = 0.00 feet
Storage provided at permanent pool depth = 0 CF (calculated)
Total storage required for normal + storage pool = 4222 CF
Stage (above invert) associated with this storage = 0.59 feet
1 Therefore, depth required above normal pool for storm storage = 0.59 feet
7.11 inches
Therefore set crest of principal spillway at stage = 0.59 feet
and EL = 604.59 feet
• At principal spillway crest, storm pool storage provided = 4222 CF
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond#3 Calcs Page 6
Highway 29 Water Quality Siphon J.C. Diaz, EI
GWH-6040 Pond#3 Caks 12/17/2007
•
•
•
Siphon 0 =
No. siphons =
Ks =
b=
Cd siphon =
Normal Pool Elevation =
Volume @ Normal Pool =
WSEL @ 1" Runoff Volume =
Calculated WSEL increment =
1 inches
1
7663.5
1.1386
0.60
604.00 feet
0 CF
604.59 feet
0.051 feet
WSEL
(feet) Vol. Stored
(cf) Siphon Flow
(cfs) Avg. Flow
(cfs) Incr. Vol.
(cf) Incr. Time
(sec)
604.592 4222 0.019
604.541 3807 0.019 0.019 414 21824
604.490 3398 0.018 0.018 409 22679
604.438 2995 0.017 0.017 403 23674
604.387 2598 0.015 0.016 397 24857
604.335 2209 0.014 0.015 389 26297
604.284 1828 0.013 0.014 381 28112
604.233 1456 0.011 0.012 372 30510
604.181 1096 0.010 0.011 360 33917
604.130 750 0.008 0.009 346 39403
604.078 422 0.005 0.006 327 51618
Conclusion : Use 1 - 1.0" Diameter Water Quality Orifice to drawdown the accumulated
volume from the 1.0 " storm runoff, with a required time of about 3 days.
Drawdown Time = 3.51 days
X:\Projects\GW14\GWH-06040\Storm\Construction Drawings\Design Files\Pond#3 Calcs
Page 7
Highway 29 Anti-Flotation Calculation J.C. Diaz, El
GWH-6040 Pond#3 Calculations 12/18/2007
• Input Data =>
Inside wall dimension of riser (1) = 5.0 feet
Inside wall dimension of riser (2) = 5.0 feet
Min. wall thickness of riser = 6.0 inches
Inside height of Riser* = 8.50 feet
Side weir/orifice area = 0.01 square feet
Concrete unit weight = 142.0 PCF Note: NC Products lists unit
OD of barrel exiting riser = 45.5 inches wt. of riser concrete at 142 PCF.
Size of drain pipe (if present) = 8.0 inches
Volume of Trashrack = 61.7 CF
*Note- from riser floor to inside of top
Concrete Present -
Total amount of concrete:
Riser Walls = 93.50 CF
Adjust for openings:
Opening for barrel = 5.65 CF
Opening for drain pipe = 0.17 CF
Opening for weirs = 0.00 CF
Total Concrete present, adjusted for openings = 87.677 CF
Weight of concrete present = 12450 lbs
Amount of water displaced ^>
Total water displaced by riser/barrel structure = 367.700 CF
Weight of water displaced = 22944 lbs
• Calculate amount of concrete to be added to riser =>

Safety factor to use = 1.15 (recommend 1.15 or higher)
Calculate size of base for riser assembly =>
Outside Dimension (1) = 9.000 feet
Outside Dimension (2) = 9.000 feet
Thickness = 30.0 inches
Concrete Present = 202.500 CF
Check validity of base as designed =>
Total Water Displaced = 570.200 CF
Total Concrete Present = 290.177 CF
Total Water Displaced = 35580 Ibs
Total Concrete Present = 41205 Ibs
Actual safety factor = 1.16
Results of design =>
•
Outside Base Dimensions (rectangular) = 9.00 feet a 9.00 feet
Base Thickness = 30.00 inches
CY of concrete total in base = 7.50 CY
Concrete unit weight in added base >= 142 PCF
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond#3 Calculations Page 8
Highway 29
GWH-6040
•
•
•
Outfall
Pond#3 Calculations
J.C. Diaz, El
12/18/2007
RIP RAP APRON SIZING
Based on Army Corps of Engineers Reports H-70-2 H-72-5,
and N.J. Standards for Soil Erosion and Sediment Control
(1999)
Input:
Pipe Diameter, Do 36 Inches or 3 Feet
Peak Flow, Q10 47 CFS (Always use FULL FLOW)
Tailwater depth, Tw 1.5 Feet (If Unknown, use 0.2 x Diameter in Feet)

Design La= (1.8 x Do/Q) +7Do,
Do^0.5 If TW <Do/2, Wa = 3Do + La
Apron Length, La = 27.1 Feet Long If TW > Do/2,Wa = 3Do+ 0.4La
Apron Width, Wa = 19.9 Feet Wide (Only if no well-defined channel downstream)
d5o Stone Size = 0.42 d50 in Feet
5.0 d5o in Inches d50 = 0.016/TW x („`1.73
RIP RAP GRADATION PER NCDOT SPECIFICATIONS
RIP RAP MINIMUM MIDRANGE MAXIMUM
CLASS (IN.) (IN.) (IN.)
A 2 4 6
B 5 8 12
1 5 10 17
2 9 14 23
SOIL TEXTURE ALLOWABLE VELOCITY
Sand Loam 2.5 s
Silt Loam, Loam 3.0 fps
Sand Clay Loam 3.5 s
Clay Loam 4.0 fps
Clay, fine Gravel 5.0 fps
Cobbles 5.5 fps
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond#3 Calculations
Page 9
0 Wet Pond #3
Pondpack Version 8 Output - Outlet Rating Curve
•
•
Highway 29
GWH-06040
•
Type.... Outlet Input Data Page 1.01
Name.... Pond 3
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
REQUESTED POND WS ELEVATIONS:
Min. Elev.= 604.00 ft
Increment = .20 ft
Max. Elev.= 608.00 ft
OUTLET CONNECTIVITY
---> Forward Flow Only (Upstream to DnStream)
<--- Reverse Flow Only (DnStream to Upstream)
<---> Forward and Reverse Both Allowed
•
•
Structure
Inlet Box
Orifice-Circular
Culvert-Circular
TW SETUP, DS Channel
SIN: 6217012070C3
PondPack Ver. 8.0058
No. Outfall
------- E1, ft
--------- E2, ft
---------
----
RI ---> BA 606.500 608.000
SI ---> BA 604.000 608.000
BA ---> TW 598.000 608.000
The John R. McAdams Company
Time: 11:03 AM Date: 12/18/2007
•
Type.... Outlet Input Data
Name.... Pond 3
Page 1.02
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.'PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
OUTLET STRUCTURE INPUT DATA
Structure ID = RI
Structure Type
------------ = Inlet Box
-------------
------
-----
# of Openings = 1
Invert Elev. = 606.50 ft
Orifice Area = 25.0000 sq.ft
Orifice Coeff. _ .600
Weir Length = 20.00 ft
Weir Coeff. = 3.000
K, Submerged = .000
K, Reverse = 1.000
Kb,Barrel = .000000 (per ft of full flow)
Barrel Length = .00 ft
Mannings n = .0000
Structure ID = SI
Structure Type = Orifice-Circular
------------------------------------
# of Openings = 1
Invert Elev. = 604.00 ft
Diameter = .0833 ft
Orifice Coeff. _ .600
•
•
SIN: 6217012070C3 The John R. McAdams Company
PondPack Ver. 8.0058 Time: 11:03 AM Date: 12/18/2007
•
Type.... Outlet Input Data
Name.... Pond 3
Page 1.03
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
OUTLET STRUCTURE INPUT DATA
Structure ID = BA
Structure Type
- = Culvert-Circular
------------------
-----------------
No. Barrels = 1
Barrel Diameter = 3.0000 ft
Upstream Invert = 598.00 ft
Dnstream Invert = 597.50 ft
Horiz. Length = 90.00 ft
Barrel Length = 90.00 ft
Barrel Slope = .00556 ft/ft
OUTLET CONTROL DATA...
Mannings n = .0130
Ke = .5000
Kb = .007228
Kr = .5000
HW Convergence = .001
(forward entrance loss)
(per ft of full flow)
(reverse entrance loss)
+/- ft
INLET CONTROL DATA...
Equation form = 1
Inlet Control K = .0098
Inlet Control M = 2.0000
Inlet Control c = .03980
Inlet Control Y = .6700
T1 ratio (HW/D) = 1.157
T2 ratio (HW/D) = 1.304
Slope Factor = -.500
•
•
Use unsubmerged inlet control Form 1 equ. below T1 elev.
Use submerged inlet control Form 1 equ. above T2 elev.
In transition zone between unsubmerged and submerged inlet control,
interpolate between flows at T1 & T2...
At Tl Elev = 601.47 ft ---> Flow 42.85 cfs
At T2 Elev = 601.91 ft ---> Flow = 48.97 cfs
SIN: 6217012070C3
PondPack Ver. 8.0058
The John R. McAdams Company
Time: 11:03 AM Date: 12/18/2007
•
Type.... Outlet Input Data
Name.... Pond 3
Page 1.04
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
OUTLET STRUCTURE INPUT DATA
Structure ID = TW
Structure Type = TW SETUP, DS Channel
------------------------------------
FREE OUTFALL CONDITIONS SPECIFIED
CONVERGENCE TOLERANCES ...
Maxi mum Iterations= 30
Min. TW tolerance = .01 ft
Max. TW tolerance = .01 ft
Min. HW tolerance = .01 ft
Max. HW tolerance = .01 ft
Min. Q tolerance = .10 cfs
Max. Q tolerance = .10 cfs
•
•
SIN: 6217012070C3 The John R. McAdams Company
PondPack Ver. 8.0058 Time: 11:03 AM Date: 12/18/2007
•
•
•
Type.... Composite Rating Curve
Name.... Pond 3
Page 1.05
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
***** COMPOSITE OUTFLOW SUMMARY ****
WS Elev, Total Q Notes
---------------- -------- Converge -------------------------
Elev. Q TW Elev Error
ft cfs ft +/-ft Contributing Structures
-------- ------- -------- ----- --------------------------
604.00 .00 Free Outfall (no Q: RI,SI,BA)
604.20 .01 Free Outfall SI,BA (no Q: RI)
604.40 .02 Free Outfall SI,BA (no Q: RI)
604.60 .02 Free Outfall SI,BA (no Q: RI)
604.80 .02 Free Outfall SI,BA (no Q: RI)
605.00 .03 Free Outfall SI,BA (no Q: RI)
605.20 .03 Free Outfall SI,BA (no Q: RI)
605.40 .03 Free Outfall SI,BA (no Q: RI)
605.60 .03 Free Outfall SI,BA (no Q: RI)
605.80 .03 Free Outfall SI,BA (no Q: RI)
606.00 .04 Free Outfall SI,BA (no Q: RI)
606.20 .04 Free Outfall SI,BA (no Q: RI)
606.40 .04 Free Outfall SI,BA (no Q: RI)
606.50 .04 Free Outfall SI,BA (no Q: RI)
606.60 1.94 Free Outfall RI,SI,BA
606.80 9.90 Free Outfall RI,SI,BA
607.00 21.26 Free Outfall RI,SI,BA
607.20 35.19 Free Outfall RI,SI,BA
607.40 51.28 Free Outfall RI,SI,BA
607.60 69.27 Free Outfall RI,SI,BA
607.80 88.96 Free Outfall RI,SI,BA
608.00 100.21 Free Outfall RIBA (no Q: SI)
SIN: 6217012070C3 The John R. McAdams Company
PondPack Ver. 8.0058 Time: 11:03 AM
Date: 12/18/2007
i
Wet Pond #3
Pondpack Version 8 Output - Worst Case Scenario Outlet Rating Curve
•
•
Highway 29
GWH-06040
•
Type.... Outlet Input Data Page 1.01
Name.... Pond 3 100
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
REQUESTED POND WS ELEVATIONS:
Min. Elev.= 604.00 ft
Increment = .20 ft
Max. Elev.= 608.00 ft
OUTLET CONNECTIVITY
---> Forward Flow Only (UpStream to DnStream)
<--- Reverse Flow Only (DnStream to UpStream)
<---> Forward and Reverse Both Allowed
Structure No. Outfall E1, ft E2, ft
----------------- ---- ------- --------- ---------
Inlet Box RI ---> BA 606.500 608.000
Culvert-Circular BA ---> TW 598.000 608.000
TW SETUP, DS Channel
0
•
SIN: 6217012070C3
PondPack Ver. 8.0058
The John R. McAdams Company
Time: 11:04 AM Date: 12/18/2007
•
Type.... Outlet Input Data Page 1.02
Name.... Pond 3 100
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
OUTLET STRUCTURE INPUT DATA
Structure ID = RI
Structure Type
----- = Inlet Box
-------------
------
------------
# of Openings = 1
Invert Elev. = 606.50 ft
orifice Area = 25.0000 sq.ft
Orifice Coeff. _ .600
Weir Length = 20.00 ft
Weir Coeff. = 3.000
K, Submerged = .000
K, Reverse = 1.000
Kb,Barrel = .000000 (per ft of full flow)
Barrel Length = .00 ft
Mannings n = .0000
•
•
SIN: 6217012070C3 The John R. McAdams Company
PondPack Ver. 8.0058 Time: 11:04 AM Date: 12/18/2007
•
Type.... Outlet Input Data Page 1.03
Name.... Pond 3 100
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
OUTLET STRUCTURE INPUT DATA
•
•
Structure ID = BA
Structure Type = Culvert-Circular
------------------------------------
No. Barrels = 1
Barrel Diameter = 3.0000 ft
Upstream Invert = 598.00 ft
Dnstream Invert = 597.50 ft
Horiz. Length = 90.00 ft
Barrel Length = 90.00 ft
Barrel Slope = .00556 ft/ft
OUTLET CONTROL DATA...
Mannings n = .0130
Ke = .5000 (forward entrance loss)
Kb = .007228 (per ft of full flow)
Kr = .5000 (reverse entrance loss)
HW Convergence = .001 +/- ft
INLET CONTROL DATA...
Equation form = 1
Inlet Control K = .0098
Inlet Control M = 2.0000
Inlet Control c = .03980
Inlet Control Y = .6700
T1 ratio (HW/D) = 1.157
T2 ratio (HW/D) = 1.304
Slope Factor = -.500
Use unsubmerged inlet control Form 1 equ. below T1 elev.
Use submerged inlet control Form 1 equ. above T2 elev.
In transition zone between unsubmerged and submerged inlet control,
interpolate between flows at T1 & T2...
At T1 Elev = 601.47 ft ---> Flow = 42.85 cfs
At T2 Elev = 601.91 ft ---> Flow = 48.97 cfs
SIN: 6217012070C3 The John R. McAdams Company
PondPack Ver. 8.0058 Time: 11:04 AM Date: 12/18/2007
Type.... Composite Rating Curve Page 1.04
Name.... Pond 3 100
File.... X:\Projects\GWH\GWH-06040\ Storm\Con struction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B . Hopkins
Project Title: Highway 29
Project Comments:
* **** COMPOSITE OUTF LOW SUMMARY ****
CUMULATIVE HGL CONVERGENCE ER ROR .000 (+/- ft)
WS Elev, Total Q Notes
-------- -------- -------- Converge -------- -----------------
Elev. Q TW Elev Error
ft
-------- cfs
------- ft
-------- +/-ft
----- Contribu
--------- ting Structures
---
---------

604.00
.00
603.16
.0.00
(no Q: --
---
RI,BA)
604.20 .00 603.16 .000 (no Q: RIBA)
604.40 .00 603.16 .000 (no Q: RIBA)
604.60 .00 603.16 .000 (no Q: RIBA)
604.80 .00 603.16 .000 (no Q: RIBA)
605.00 .00 603.16 .000 (no Q: RIBA)
605.20 .00 603.16 .000 (no Q: RIBA)
605.40 .00 603.16 .000 (no Q: RIBA)
605.60 .00 603.16 .000 (no Q: RIBA)
605.80 .00 603.16 .000 (no Q: RIBA)
606.00 .00 603.16 .000 (no Q: RIBA)
606.20 .00 603.16 .000 (no Q: RIBA)
606.40 .00 603.16 .000 (no Q: RI,BA)
606.50 .00 603.16 .000 (no Q: RIBA)
606.60 1.90 603.16 .000 RIBA
606.80 9.86 603.16 .000 RIBA
607.00 21.21 603.16 .000 RIBA
607.20 35.14 603.16 .000 RIBA
607.40 51.23 603.16 .000 RIBA
607.60 69.22 603.16 .000 RI,BA
607.80 83.29 603.16 .000 RIBA
608.00 85.06 603.16 .000 RIBA
•
SIN: 6217012070C3 The John R. McAdams Company
PondPack Ver. 8.0058 Time: 11:04 AM Date: 12/18/2007
•
•
Wet Pond #4 Design
Contents
•
Above Normal Pool Stage-Storage Function
Below Normal Pool Stage-Storage Function
Forebay Stage-Storage Function
Surface Area Calculations
Water Quality Volume Calculations
Drawdown Calculations
Anti-Float Calculations
Energy Dissipater Calculations
Pondpack Version 8 Output
Highway 29
GWH-06040
Highway 29
GWH-6040
•
•
Above NWSE
Pond#4 Calcs
J.C. Diaz, El
12/17/2007

Contour
(feet)

Stage
(feet)
Contour
Area
(SF) Average
Contour
Area
(SF) Incremental
Contour
Volume
(CF) Accumulated
Contour
Volume
(CF) Estimated
Stage
w/ S-S Fxn
(feet)

594.0 0.0 9335
595.0 1.0 10773 10054 10054 10054 1.01
596.0 2.0 12278 11526 11526 21580 1.97
597.0 3.0 13851 13065 13065 34644 3.00
598.0 4.0 13852 13852 13852 48496 4.03

Storage vs. Stage
60000
50000 1 1344
y = 9976.7x
LL 40000 R2 = 0.9997
U
rn 30000
M
20000
10000
0
0.0 1.0 2.0 3.0 4.0 5.0
Stage (feet)
Ks = 9976.7
b = 1.1344
•
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond#4 Calcs
Page 1
Highway 29 S-S Function J.C. Diaz, El
GWH-6040 Pond#4 Calcs 12/17/2007
• _> Stage - Storage Function
Ks = 9976.7
b = 1.1344
Zo = 594.00
•
•
Elevation Stora a Worst Case Scenario Storage
[feet] [cf] [acre-feet] [acre-feet]
594.00 0 0.000 -
594.2 1607 0.037 -
594.4 3528 0.081 -
594.6 5589 0.128 -
594.8 7746 0.178 -
595 9977 0.229 -
595.2 12269 0.282 -
595.4 14614 0.335 -
595.6 17004 0.390 -
595.8 19434 0.446 -
596 21902 0.503 0.000
596.2 24402 0.560 0.057
596.4 26934 0.618 0.116
596.6 29494 0.677 0.174
596.8 32081 0.736 0.234
597 34692 0.796 0.294
597.2 37328 0.857 0.354
597.4 39985 0.918 0.415
597.6 42663 0.979 0.477
597.8 45362 1.041 0.539
598 48080 1.104 0.601
X:\Projects\GWH\GWH-06040\Stonn\Constraction Drawings\Design Files\Pond#4 Calcs Page 2
Highway 29 Below NWSE J.C. Diaz, El
GWH-6040 Pond#4 Calcs 12/17/2007
Average Incremental Accumulated Estimated
Contour Contour Contour Contour Stage
Contour Stage Area Area Volume Volume w/ S-S Fxn
(feet) (feet) (SF) (SF) (CF) (CF) (feet)
588.0 0.0 1813
589.0 1.0 2681 2247 2247 2247 1.05
590.0 2.0 3428 3055 3055 5302 1.94
591.0 3.0 4237 .3833 3833 9134 2.87
592.0 4.0 5132 4685 4685 13819 3.86
593.0 5.0 6882 6007 6007 19826 5.01
594.0 6.0 9329 8106 8106 27931 6.41
•
Storage vs. Stage
30000
25000
y = 2112.4x1.39
LL 20000 R2 = 0.9952
a? 15000
0
10000
5000
0
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0
Stage (feet)
Ks = 2112.4
b = 1.39
i
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond#4 Calcs Page 3
Highway 29 Forebav 1 J.C. Diaz, El
GWH-6040 Pond#4 Calcs 12/17/2007
• Average Incremental Accumulated Estimated
Contour Contour Contour Contour Stage
Contour Stage Area Area Volume Volume w/ S-S Fxn
(feet) (feet) (SF) (SF) (CF) (CF) (feet)
589.0 0.0 321
590.0 1.0 495 408 408 408 1.02
591.0 2.0 701 598 598 1006 1.94
592.0 3.0 937 819 819 1825 2.96
593.0 4.0 1205 1071 1071 2896 4.11
•
Storage vs. Stage
3500
3000 ?
y = 397.29X1.4055
2500
LL R2 = 0.9979
v 2000
m
c 1500
N
1000
500
0
0.0 1.0 2.0 3.0 4.0 5.0
Stage (feet)
Ks = 397.29
b = 1.4055
•
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond#4 Calcs Page 4
Highway 29 Forebay 2 J.C. Diaz, El
GWH-6040 Pond#4 Calculations 4/21/2008
Average Incremental Accumulated Estimated
Contour Contour Contour Contour Stage
Contour Stage Area Area Volume Volume w/ S-S Fxn
(feet) (feet) (SF) (SF) (CF) (CF) (feet)
389.0 .0.0 171
590.0 1.0 321 246 246 246 1.02
591.0 2.0 512 417 417 663 1.93
592.0 3.0 732 622 622 1285 2.96
593.0 4.0 981 857 857 2141 4.11
•
Storage vs. Stage
2500
2000 y = 23$.4X1.551
R2 = 0.997
cLLi 1500
m
m
0 1000
500
0
0.0 1.0 2.0 3.0 4.0 5.0
Stage (feet)
Ks = 238.43
b = 1.5519
•
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond#4 Calculations Page 5
Highway 29 Forebay and Surface Area J.C. Diaz, El
GWH-6040 Pond#4 Calculations 4/21/2008
•71?}Fcltiti
Per NCDENR "Stormwater Best Management Practices the forebay volume should equal about 20% of the total
basin volume.
A. Water Quality Pond - Below Normal Pool
NWSE = 594
Stage - Storage Function
Ks = 2112.4
b= 1.39
Zo = 588
Volume = 25492 ft3
B. Forebay Volume
Forebay 1: Volume
Stage - Storage Function
Ks = 397.29
b= 1.4055 _
Zo = 589
Volume = 2788 ft3
Forebay 2: Volume
Stage - Storage Function
Ks = 238.43
b= 1.5519
• Zo = 589
Volume = 2050 ft3
% Foreba = 19.0%
II. St MACE AREA Cl1ECK
Impervious Area = 4.28 acres
Drainage Area = 6.26 acres
% Impervious = 68%
Average Depth = Accumulated Contour Volume / Surface Area
ACV = 27931 cf
SA = 9329 sf
Average Depth = 3.0 ft.
From the Greensboro Stormwater Handbook, the requi red SA/DA ratio =>
3.0 3.0 4.0
Lower Boundary => 60.0 2.40 2.03
Site % impervious => 68.4 2.80 2.80 2.34
Upper Boundary => 70.0 2.88 140
Area Required = 7635 sq.ft.
• Area Provided = 9329 s .ft.
X:\Projects\GWMGWH-06040\Storm\Construction Drawings\Design Files\Pond#4 Calculations Page 6
Highway 29 Water OualitV Volume J.C. Diaz, El
GWH-6040 Pond#4 Calcs 12/17/2007
. Ks = 9976.7
b = 1.1344
Calculation of Runoff Volume required for storage
The runoff to the pond for the V storm detention requirement is calculated using the SCS curve
number method. Impervious areas that directly enter the pond are counted as Directly Connected
Impervious Areas (DCIAs). No infiltration calculation will be provided for these areas. Areas
not directly connected will be accounted for in a composite curve number.
Using basic SCS runoff methodology, with no adju:
to initial abstractions (0.2*S and 0.8*S).
Impervious Area, directly connected (DCIA) _
@CN=
Other areas draining to pond (not DCIA) =
@CN=
;tments made
4.28 acres
98
1.98 acres
74
Runoff from DCIAs -
Precipitation amount = 1.0 inches
S = 0.204 inches (calculated)
Q* = 0.791 inches (calculated)
Runoff volume = 12288 CF
• Runoff from non-connected areas
Precipitation amount = 1.0 inches
S = 3.514 inches (calculated)
Q* = 0.023 inches (calculated)
Runoff volume = 167 CF
Therefore, total runoff from precipitation in question = 12455 CF
This amount of runoff must be stored in the pond above normal pool elevation,
and be released in a period of two (2) to five (5) days, by an inverted PVC
siphon, the invert end of which is set at permanent pool elevation.
Calculation of depth required for runoff storage pool (above normal pool)
Normal pool depth (above invert) = 0.00 feet
Storage provided at permanent pool depth = 0 CF (calculated)
Total storage required for normal + storage pool = 12455 CF
Stage (above invert) associated with this storage = 1.22 feet
1 Therefore, depth required above normal pool for storm storage = 1.22 feet
14.59 inches
Therefore set crest of principal spillway at stage = 1.22 feet
and EL = 595.22 feet
• At principal spillway crest, storm pool storage provided = 12455 CF
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond#4 Calcs Page 7
•
•
Highway 29
GWH-6040
Water Quality Siphon
Pond#4 Caks
Siphon 0 =
No. siphons =
Ks =
b=
Cd siphon =
Normal Pool Elevation =
Volume @ Normal Pool =
WSEL @ 1" Runoff Volume =
Calculated WSEL increment =
1.5 inches
1
9976.7
1.1344
0.60
594.00 feet
0 CF
595.22 feet
0.106 feet
WSEL
(feet) Vol. Stored
(cf) Siphon Flow
(cfs) Avg. Flow
(cfs) Incr. Vol.
(cf) Incr. Time
(sec)
595.216 12455 0.063
595.110 11235 0.060 0.062 1220 19715
595.005 10030 0.057 0.059 1204 20473
594.899 8843 0.054 0.056 1187 21352
594.793 7674 0.050 0.052 1169 22391
594.688 6526 0.047 0.049 1148 23648
594.582 5401 0.043 0.045 1124 25217
594.477 4304 0.038 0.040 1097 27263
594.371 3239 0.033 0.035 1065 30109
594.265 2215 0.027 0.030 1024 34525
594.160 1245 0.018 0.022 970 43125
Drawdown Time = 3.10 days
J.C. Diaz, EI
12/17/2007
Conclusion : Use 1 - 1.5" Diameter Water Quality Orifice to drawdown the accumulated
volume from the 1.0 " storm runoff, with a required time of about 3 days.
•
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond#4 Calcs
Page 8
•
Highway 29
GWH-6040
Input Data =>
Anti-Flotation Calculation
Pond#4 Calculations
Inside wall dimension of riser (1) =
Inside wall dimension of riser (2) =
Min. wall thickness of riser =
Inside height of Riser* =
Side weir area =
Concrete unit weight =
OD of barrel exiting riser =
Size of drain pipe (if present) =
Volume of Trashrack =
*Note- from riser floor to inside of top
Concrete Present =>
Total amount of concrete:
Adjust for openings:
5.0 feet
5.0 feet
6.0 inches
8.00 feet
0.01 square feet
142.0 PCF Note: NC Products lists unit
45.5 inches wt. of riser concrete at 142 PCF.
8.0 inches
61.7 CF
Riser Walls = 88.00 CF
Opening for barrel = 5.65 CF
Opening for drain pipe = 0.17 CF
Opening for weirs = 0.01 CF
Total Concrete present, adjusted for openings = 82.174 CF
Weight of concrete present = 11669 lbs
•
Amount of water displaced -
Total water displaced by riser/barrel structure = 349.740 CF
Weight of water displaced = 21824 lbs
Calculate amount of concrete to be added to riser -
Safety factor to use = 1.15 (recommend 1.15 or Ill'-'her)
Calculate size of base for riser assembly -
Outside Dimension (1) = 9.000 feet
Outside Dimension (2) = 9.000 feet
Thickness = 30.0 inches
Concrete Present = 202.500 CF
Check validity of base as designed =>
Total Water Displaced = 552.240 CF
Total Concrete Present = 284.674 CF
Total Water Displaced = 34460 Ibs
Total Concrete Present = 40424 Ibs
Actual safety factor = 1.17
0
Results of design =>
Outside Base Dimensions (rectangular) = 9.00 feet a 9.00 feet
Base Thickness = 30.00 inches
CY of concrete total in base = 7.50 CY
Concrete unit weight in added base >= 142 PCF
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond44 Calculations
J.C. Diaz, El
12/18/2007
Page 9
•
•
•
Highway 29
GWH-6040
Outfall
Pond#4 Calculations
J.C. Diaz, El
12/18/2007
RIP RAP APRON SIZING
Based on Army Corps of Engineers Reports H-70-2 H-72-5,
and N.J. Standards for Soil Erosion and Sediment Control
Input: (1999)
Pipe Diameter, Do 36 Inches or 3 Feet
Peak Flow, Qto 47 CFS (Always use FULL FLOW)
Tailwater depth, Tw 1.5 Feet ( If Unknown, use 0.2 x Diameter in Feet )

Desigrt: La= (1.8 x Do/Q) +7Do,
Do^0.5 If TW <Do/2, Wa = 3Do + La
Apron Length, La = 27.1 Feet Long If TW > Do/2,Wa = 3Do+ 0.4La
Apron Width, Wa = 19.9 Feet Wide (Only if no well-defined channel downstream )
d5o Stone Size = 0.42 d50 in Feet
5.0 d50 in Inches d50 = 0.016/TW x (q)l 33
RIP RAP G RADATION PER NCDOT SPECIFICATIONS
RIP RAP MINIMUM MIDRANGE MAXIMUM
CLASS (IN.) (IN.) (IN.)
A 2 4 6
B 5 8 12
1 5 10 17
2 9 14 23
SOIL TEXTURE ALLOWABLE VELOCITY
Sandy Loam 2.5 s
Silt Loam, Loam 3.0 fps
Sand Clay Loam 3.5 s
Clay Loam 4.0 fps
Clay, fine Gravel 5.0 fps
Cobbles 5.5 fps
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Pond#4 Calculations
Page 10
• Wet Pond #4
Pondpack Version 8 Output - Outlet Rating Curve
•
•
Highway 29
GWH-06040
.0
Type.... Outlet Input Data Page 1.01
Name.... Pond 4
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
REQUESTED POND WS ELEVATIONS:
Min. Elev.= 594.00 ft
Increment = .20 ft
Max. Elev.= 598.00 ft
OUTLET CONNECTIVITY
---> Forward Flow Only (Upstream to DnStream)
<--- Reverse Flow Only (DnStream to UpStream)
<---> Forward and Reverse Both Allowed
Structure No. Outfall E1, ft E2, ft
Inlet Box RI ---> BA 596.000 598.000
Orifice-Circular SI ---> BA 594.000 598.000
Culvert-Circular BA ---> TW 588.000 598.000
TW SETUP, DS Channel
•
•
SIN: 6217012070C3 The John R. McAdams Company
PondPack Ver. 8.0058 Time: 10:06 AM Date: 12/19/2007
•
Type.... Outlet Input Data
Name.... Pond 4
Page 1.02
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
OUTLET STRUCTURE INPUT DATA
Structure ID = RI
Structure Type
----------------- = Inlet Box
------------
-------
# of Openings = 1
Invert Elev. = 596.00 ft
Orifice Area = 25.0000 sq.ft
Orifice Coeff. _ .600
Weir Length = 20.00 ft
Weir Coeff. = 3.000
K, Submerged = .000
K, Reverse = 1.000
Kb,Barrel = .000000 (per ft of full flow)
Barrel Length = .00 ft
Mannings n = .0000
Structure ID = SI
Structure Type = Orifice-Circular
------------------------------------
# of Openings = 1
Invert Elev. = 594.00 ft
Diameter = .1300 ft
Orifice Coeff. _ .600
•
•
SIN: 6217012070C3 The John R. McAdams Company
PondPack Ver. 8.0058 Time: 10:06 AM Date: 12/19/2007
•
Type.... Outlet Input Data
Name.... Pond 4
Page 1.03
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
OUTLET STRUCTURE INPUT DATA
Structure ID = BA
Structure Type
----------------- = Culvert-Circular
-------------------
No. Barrels = 1
Barrel Diameter = 3.0000 ft
Upstream Invert = 588.00 ft
Dnstream Invert = 587.50 ft
Horiz. Length = 100.00 ft
Barrel Length = 100.00 ft
Barrel Slope = .00500 ft/ft
OUTLET CONTROL DATA...
Mannings n = .0130
Ke = 1.8000
Kb = .007228
Kr = .5000
HW Convergence = .001
(forward entrance loss)
(per ft of full flow)
(reverse entrance loss)
+/- ft
INLET CONTROL DATA...
Equation form = 1
Inlet Control K = .0098
Inlet Control M = 2.0000
Inlet Control c = .03980
Inlet Control Y = .6700
Tl ratio (HW/D) = 1.158
T2 ratio (HW/D) = 1.304
Slope Factor = -.500
•
•
Use unsubmerged inlet control Form 1 equ. below T1 elev.
Use submerged inlet control Form 1 equ. above T2 elev.
In transition zone between unsubmerged and submerged inlet control,
interpolate between flows at T1 & T2...
At T1 Elev = 591.47 ft ---> Flow = 42.85 cfs
At T2 Elev = 591.91 ft ---> Flow = 48.97 cfs
SIN: 6217012070C3 The John R. McAdams Company
PondPack Ver. 8.0058 Time: 10:06 AM Date: 12/19/2007
•
Type.... Outlet Input Data
Name.... Pond 4
Page 1.04
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project. Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
OUTLET STRUCTURE INPUT DATA
Structure ID = TW
Structure Type = TW SETUP, DS Channel
------------------------------------
FREE OUTFALL CONDITIONS SPECIFIED
CONVERGENCE TOLERANCES ...
Maximum Iterations= 30
Min. TW tolerance = .01 ft
Max. TW tolerance = .01 ft
Min. HW tolerance = .01 ft
Max. HW tolerance = .01 ft
Min. Q tolerance = .10 cfs
Max. Q tolerance = .10 cfs
•
•
SIN: 6217012070C3 The John R. McAdams Company
PondPack Ver. 8.0058 Time: 10:06 AM Date: 12/19/2007
•
•
•
Type.... Composite Rating Curve
Name.... Pond 4
Page 1.05
File.... X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Pond Pack\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
WS Elev, Total Q
Elev. Q
ft
-------- cfs
-------
594.00 .00
594.20 .02
594.40 .04
594.60 .05
594.80 .05
595.00 .06
595.20 .07
595.40 .07
595.60 .08
595.80 .08
596.00 .09
596.20 5.46
596.40 15.28
596.60 27.99
596.80 43.04
597.00 60.11
597.20 78.78
597.40 79.91
597.60 81.01
597.80 82.11
598.00 83.18
SIN: 6217012070C3
PondPack Ver. 8.0058
***** COMPOSITE OUTFLOW SUMMARY ****
-------- Converge
TW Elev Error
ft +/-ft
-------- -----
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Free Outfall
Notes
-------------------------
Contributing Structures
(no Q: RI,SI,BA)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
SI,BA (no Q: RI)
RI,SI,BA
RI,SI,BA
RI,SI,BA
RI,SI,BA
RI,SI,BA
RI,BA (no Q: SI)
RIBA (no Q: SI)
RIBA (no Q: SI)
RIBA (no Q: SI)
RI,BA (no Q: SI)
The John R. McAdams Company
Time: 10:06 AM Date: 12/19/2007
•
•
•
Wet Pond #4
Pondpack Version 8 Output - Worst Case Scenario Outlet Rating Curve
Highway 29
GWH-06040
•
Type.... Outlet Input Data Page 1.01
Name.... Pond 4 100
File.... C:\Documents and Settings\diaz\Desktop\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
REQUESTED POND WS ELEVATIONS:
Min. Elev.= 594.00 ft
Increment = .20 ft
Max. Elev.= 598.00 ft
OUTLET CONNECTIVITY
---> Forward Flow Only (Upstream to DnStream)
<--- Reverse Flow Only (DnStream to UpStream)
<---> Forward and Reverse Both Allowed
•
•
Structure
-----------------
Inlet Box
Culvert-Circular
TW SETUP, DS Channel
SIN: 6217012070C3
PondPack Ver. 8.0058
No. Outfall E1, ft E2, ft
---- ------- --------- ---------
RI ---> BA 596.000 598.000
BA ---> TW 588.000 598.000
The John R. McAdams Company
Time: 11:12 AM Date: 12/18/2007
•
Type.... Outlet Input Data
Name.... Pond 4 100
Page 1.02
File.... C:\Documents and Settings\diaz\Desktop\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
OUTLET STRUCTURE INPUT DATA
Structure ID = RI
Structure Type
- = Inlet Box
-------------
------
---------------
-
# of Openings = 1„
Invert Elev. = 596.00 ft
Orifice Area = 25.0000 sq.ft
Orifice Coeff. _ .600
Weir Length = 20.00 ft
Weir Coeff. = 3.000
K, Submerged = .000
K, Reverse = 1.000
Kb,Barrel = .000000 (per ft of full flow)
Barrel Length = .00 ft
Mannings n = .0000
•
•
SIN: 6217012070C3 The John R. McAdams Company
PondPack Ver. 8.0058 Time: 11:12 AM Date: 12/18/2007
•
Type.... Outlet Input Data
Name.... Pond 4 100
Page 1.03
File.... C:\Documents and Settings\diaz\Desktop\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
OUTLET STRUCTURE INPUT DATA
Structure ID = BA
Structure Type = Culvert-Circular
------------------
------------------
No. Barrels = 1
Barrel Diameter = 3.0000 ft
Upstream Invert = 588.00 ft
Dnstream Invert = 587.50 ft
Horiz. Length = 100.00 ft
Barrel Length = 100.00 ft
Barrel Slope = .00500 ft/ft
OUTLET CONTROL DATA...
Mannings n = .0130
Ke = 1.8000
Kb = .007228
Kr = .5000
HW Convergence = .001
(forward entrance loss)
(per ft of full flow)
(reverse entrance loss)
+/- ft
INLET CONTROL DATA...
Equation form = 1
Inlet Control K = .0098
Inlet Control M = 2.0000
Inlet Control c = .03980
Inlet Control Y = .6700
T1 ratio (HW/D) = 1.158
T2 ratio (HW/D) = 1.304
Slope Factor = -.500
is
•
Use unsubmerged inlet control Form 1 equ. below T1 elev.
Use submerged inlet control Form 1 equ. above T2 elev.
In transition zone between unsubmerged and submerged inlet control,
interpolate between flows at T1 & T2...
At T1 Elev = 591.47 It ---> Flow = 42.85 cfs
At T2 Elev = 591.91 ft ---> Flow = 48.97 cfs
SIN: 6217012070C3 The John R. McAdams Company
PondPack Ver. 8.0058 Time: 11:12 AM Date: 12/18/2007
•
Type.... Composite Rating Curve
Name.... Pond 4 100
Page 1.04
File.... C:\Documents and Settings\diaz\Desktop\RATINGCURVES.PPW
Title... Project Date: 7/16/2007
Project Engineer: Derick B. Hopkins
Project Title: Highway 29
Project Comments:
***** COMPOSITE OUTFLOW SUMMARY ****
CUMULATIVE HGL CONVERGENCE ERROR .000 (+/- ft)
•
•
WS Elev, Total Q
Elev. Q
ft
-------- cfs
-------
594.00 .00
594.20 .00
594.40 .00
594.60 .00
594.80 .00
595.00 .00
595.20 .00
595.40 .00
595.60 .00
595.80 .00
596.00 .00
596.20 5.37
596.40 15.18
596.60 27.88
596.80 42.93
597.00 65.91
597.20 67.28
597.40 68.63
597.60 69.94
597.80 71.24
598.00 72.50
SIN: 6217012070C3
PondPack Ver. 8.0058
------- Converge
TW Elev Error
ft +/-ft
------- -----
592.24 .000
592.24 .000
592.24 .000
592.24 .000
592.24 .000
592.24 .000
592.24 .000
592.24 .000
592.24 .000
592.24 .000
592.24 .000
592.24 .000
592.24 .000
592.24 .000
592.24 .000
592.24 .000
592.24 .000
592.24 .000
592.24 .000
592.24 .000
592.24 .000
Notes
-----------------------
Contributing Structures
-----------------------
(no Q: RIBA)
(no Q: RI,BA)
(no Q: RI,BA)
(no Q: RIBA)
(no Q: RI,BA)
(no Q: RIBA)
(no Q: RIBA)
(no Q: RIBA)
(no Q: RI,BA)
(no Q: RIBA)
(no Q: RIBA)
RIBA
RIBA
RIBA
RIBA
RIBA
RIBA
RI,BA
RI,BA
RIBA
RIBA
The John R. McAdams Company
Time: 11:12 AM Date: 12/18/2007
¦ ? r

rr
J
?p .
'-
NN o„
sr a °??
N? Yp1
Y
r
¦
leX-R-
rI',

E., ? - --
?
>
d
I -2?ca)
01'.
GRAPHIC SCALE
500 0 250 500 1000
1 inch = 500 ft.

PROJECT NO. GWH-06040
HIGHWAY 29 THE JOHN R. McADAMS
A
FILENAME: COMPANY, INC.
GWH06040-X STORM.DWG
ENGINEERS/PLANNERS/SURVEYORS
y
d SCALE:
"
' NORTH CAROLINA
CHARLOTTE
=500
? , RESEARCH TRIANGLE PARK, NC
BOX 14005 ZIP 27709-4005
P
O
DATE: MAP
WATERSHED ZONING .
.
07-12-2007 [phone] '

PROJECT NO. GWH-06040
FILENAME:
n
a
b
a
FITIGHWAY 2?9`
CHARLOTTE, N® CAROLINA
WATERSHED NIAP
A THE JOHN R. McADAMS
COMPANY, INC.
ENGINEERS/PLANNERS/SURVEYORS
RESEARCH TRIANGLE PARK, NC
P.O. BOX 14005 ZIP 27709-4005
[phone]
SCALE: 1"=500'
DATE: 07-12-2007
> t? GRAPHIC SCALE
500 0 250 500 1000
d
1 inch = 500 ft.
•
•
Project: GWH-06040
Basin Model : Pre-diversion analysis
HEC-HMS Apr 04 13:30:52 EDT 2008
0
•
•
Project: GWH-06040 Simulation Run: Pre-50-year
Start of Run: 12Ju12007, 00:00 Basin Model:
End of Run: 13Jul2007, 00:01 Meteorologic Model:
Compute Time: 04Apr2008, 13:29:07 Control Specifications
Volume Units: AC-FT
Pre-diversion analysis
50-year
1 min-dt
Hydrologic
Element Drainage Area
(M12) Peak Discharg
(CFS) Time of Peak Volume
(AC-FT)
Entire Watershed 0.4768 794.82 12Jul2007, 12:36 118.79
0
•
Project Site (Zoned Multi-family - 12/ac, R-12MF) 90 Assume as condos (65% impervious)
Business (B-1) 94 85% impervious
Industrial (I-2) 91 72% impervious
Industrial (I-2CD) 91 72% impervious
Single Family - 3/acre (R-3) 81 30% impervious
Multi-family - 12/ac (R-I2MF) 90 Assume as condos (65% impervious)
Multi-family - 22/ac (R-22W) 90 Assume as condos (65% impervious)
Mixed Use - max floor ratio 8 (MX-2) 94 Assume commercial (85% impervious)
ENTIRE WATERSHED ZONING CONDITIONS
I. Watershed Composition:
H. Time of Concentration Information:
Composite SCS CN = 83
Tc was calculated using SCS TR-55 SEGMENT #1 -> OVERLAND FLOW
• Segment H) = I
Surface Manning n (see below) = 0.4
Flow Length, L (<=300') = 100
2-Year, 24 Hour Rainfall Depth = i.44
Land Slope = 0.0144
Total Basin Area 305.14
Total On-site Basin Area 42.50
Total Off-site Basin Area 262.64
Cover Description Area acres Impervious Area acres
Project Site 42.50 27.63
Business (B-1) 0.91 0.77
Industrial (I-2) 458 3.30
Industrial (I-2CD) 13.62 9.81
Single Family - 3/acre (R-3) 240.42 72.13
Multi-family - 12/ac (R-12MF) 0.73 0.47
Multi-family - 22/ac (R-22MF) 0.40 0.26
Mixed Use - max floor ratio 8 MX-2 1.98 1.68
Total = 305.14 Acres 116.05 Acres
0.4768 Sq. Miles 38.03%
Wooded (light underbrush)
feet
inches Begin EL
ft/ft End EL.
Travel Time = 23.62 minutes
SEGMENT #1-> CONCENTRATED FLOW
Segment ID = 2
Surface Description = Unpaved (Paved or Unpaved)
Flow Length, L = 213631 ft Begin EL.
Watercourse Slope = 0.036 ft /ft End EL.
Average Velocity= 3.04 ft/s
Travel Time = 11.70 minutes
SEGMENT #3 -> CHANNEL FLOW
Segment ID = 3
Length = 5469.12 ft Begin EL.
Slope = 0.0143 ft/ft End EL.
Manning's n = 0.045 natural stream
Flow Area = 16.00 sf (Assume 3'x3' channel)
Wetted Perimeter= 12.00 ft (Assume 3'x3' channel)
Channel Velocity= 4.79 ft/sec
Segment Time = 19.03 minutes
0
TOTAL TRAVEL TIME= 54.35 MINUTES
SCS LAG TIME = 32.61 MINUTES
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Diversion Analysis\Pre-Diversion Hydrologic Calculations
733.4ft
732.Ofl
732.Oft
656.0ft
656.Oft
578 Oft
Page I
? 0
•
Project : GWH-06040
Basin Model : Post-diversion analysis
HEC-HMS Apr 04 13:31:09 EDT 2008
0
•
•
Project: GWH-06040 Simulation Run: Post-50-year
Start of Run: 12Ju12007, 00:00 Basin Model:
End of Run: 13Ju12007, 00:01 Meteorologic Model:
Compute Time: 04Apr2008, 13:29:03 Control Specifications:
Volume Units: AC-FT
Post-diversion analysis
50-year
1 min-dt
Hydrologic
Element Drainage Area
(M12) Peak Discharg
(CFS) Time of Peak Volume
(AC-FT)
Bypass 0.0084 28.31 12Jul2007, 12:04 1.68
Bypass to Reach 0.0156 52.57 12Jul2007, 12:04 3.12
Entire Watershed 0.4904 772.81 12Jul2007, 12:35 116.18
Junction-1 0.4486 740.69 12Jul2007, 12:32 108.10
Offsite 0.4104 709.27 12Jul2007, 12:33 99.95
Pond 1 0.0236 49.22 12Jul2007, 12:12 4.14
Pond 2 0.0187 56.10 12Ju12007, 12:08 4.41
Pond 3 0.0039 6.83 12Ju12007, 12:16 0.62
Pond 4 0.0098 39.98 12Jul2007, 12:06 2.36
Reach-1 0.4486 740.69 12Jul2007, 12:36 108.00
To Pond 1 0.0236 105.34 12Ju12007, 12:04 6.49
To Pond 2 0.0187 84.77 12Jul2007, 12:04 5.25
To Pond 3 0.0039 17.68 12Jul2007, 12:04 1.10
To Pond 4 0.0098 45.70 12Ju12007, 12:04 2.87
0
Highway 29 Post-Diversion Hydrologic Calculations J.C. Diaz, EI
GWH-06040 Offsite 4/4/2008
•
Business (B-1) 94 85% impervious
Industrial (1-2) 91 72% impervious
Industrial (1-2CD) 91 72% impervious
Single Family - 3/acre (R-3) 81 30% impervious
Multi-family - 12/ac (R-12MF) 90 Assume as condos (65% impervious)
Multi-family - 22/ac (R-22MF) 90 Assume as condos (65% impervious)
Mixed Use - max floor ratio 8 (MX-2) 94 Assume commercial (85% impervious)
I Watershed Composition:
Total Basin Area 262.64
Total On-site Basin Area 0.00
Total Off-site Basin Area 262.64
Cover Description Area [acres] Impervious Area acres
Business (B-1) 0.91 0.77
Industrial (I-2) 4.58 3.30
Industrial (I-2CD) 13.62 9.81
Single Family - 3/acre (R-3) 240.42 72.13
Multi-family - 12/ac (R-12MF) 0.73 0.47
Multi-family - 22/ac (R-22MF) 0.40 0.26
Mixed Use - max floor ratio 8 MX-2 1.98 1.68
Total = 262.64 Acres 88.42 Acres
0.4104 Sq. Miles 33.67%
Composite SCS CN = 82
II . Time of Concentration Information:
*** Tc was calculated using SCS TR-55 SEGMENT #1-> OVERLAND FLOW
Segment ID = 1
Surface Manning n (see below) = 0.4 Wooded (light underbrush)
Flow Length, L (<=3001) = 100 feet
2-Year, 24 Hour Rainfall Depth = 3.44 inches Begin EL.
Land Slope = 0.0144 ft/ft End EL.
Travel Time = 23.62 minutes
SEGMENT #2 -> CONCENTRATED FLOW
Segment ID = 2
Surface Description = Unpaved (Paved or Unpaved)
Flow Length, L = 213631 ft Begin EL.
Watercourse Slope = 0.036 ft/ft End EL.
Average Velocity = 3.04 ft/s
Travel Time = 11.70 minutes
SEGMENT #3 -> CHANNEL FLOW (to Junction-])
Segment ID = 3
Length = 4089 ft Begin EL.
Slope = 0.0152 ft/ft End EL.
Manning's n = 0.045 natural stream
Flow Area = 16.00 sf (Assume 3'x3' channel)
Wetted Perimeter = 12.00 ft (Assume 3'xT channel)
Channel Velocity = 4.94 ft/sec
Segment Time = 13.80 minutes
TOTAL TRAVEL TIME= 49.12 MINUTES
SCS LAG TIME = 29.47 MINUTES
•
X:\Projects\GWMGWH-06040\Storm\Construction Drawings\Diversion Analysis\Post-Diversion Hydrologic Calculations
733.4tt
732.Oft
732.Oft
656.Oft
656.Oft
594.Oft
Page 1
Highway 29 Post-Development Hydrologic Calculations
GWH-06040 Subbasin 1 - To Pond I
is
Cover Condition SCS CN Comments
Impervious 98 100%HSG'C' Soils
Open 74 100% HSG'C'Soils
Wooded 70 100% HSG'C'Soils
Water 100 100%HSG'C' Soils
A. Watershed Breakdown
Contributing Area SCS CN Area
acres Comments
On-Site Impervious 98 7.33 -
On-Site Open 74 6.22 Assume good condition
On-Site Wooded 70 0.00 Assume good condition
On-Site Water 100 0.00 -
Off-Site Impervious 98 0.54 -
Off-Site Open 74 1.02 Assume good condition
Off-Site Wooded 70 0.00 Assume good condition
Off-Site Water 100 0.00 -
Total area = 15.11 acres
0.0236 sq.mi.
Composite SCS CN = 87
•A
Time of Concentration = 5.00 minutes
SCS Lag Time = 3.00 minutes (SCS Lag = 0.6* Tc)
Time Increment = 0.87 minutes (= 0.29*SCS Lag)
•
Time of Concentration Information
Time of concentration is calculated using the SCS Segmental Approach (TR-55). Assumed minimum of 5 minutes.
J.C. Diaz, El
4/4/2008
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Post-Development Hydrologic Calculations Page 2 of 8
Highway 29 Post-Development Hydrologic Calculations J.C. Diaz, El
GWH-06040 Subbasin I - To Pond 2 4/4/2008
I* Mwwwww- M-M
Cover Condition SCS CN Comments
impervious 98 100% HSG 'C' Soils
Open 74 100% HSG 'C' Soils
Wooded 70 100% HSG'C' Soils
Water 100 100%HSG'C' Soils
A. Watershed Breakdown
Contributing Area SCS CN Area
acres Comments
On-Site Impervious 98 7.18 -
On-Site Open 74 4.54 Assume good condition
On-Site Wooded 70 0.00 Assume good condition
On-Site Water 100 0.00 -
Off-Site Impervious 98 0.00 -
Off-Site Open 74 0.28 Assume good condition
Off-Site Wooded 70 0.00 Assume good condition
Off-Site Water 100 0.00 -
Total area = 12.00 acres
0.0188 sq.mi.
Composite SCS CN = 88
• B. Time of Concentration Information
Time of concentration is calculated using the SCS Segmental Approach (TR-55). Assumed minimum of 5 minutes.
Time of Concentration = 5.00 minutes
SCS Lag Time = 3.00 minutes (SCS Lag = 0.6* Tc)
Time Increment = 0.87 minutes (= 0.29*SCS Lag)
t
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Post-Development Hydrologic Calculations Page 3 of 8
Highway 29 Post-Development Hydrologic Calculations
GWH-06040 Subbasin 1 - To Pond 3
•
Cover Condition SCS CN Comments
Impervious 98 100%HSG'C' Soils
Open 74 100% HSG 'C' Soils
Wooded 70 100%HSG'C' Soils
Water 100 100% HSG'C'Soils

A. Watershed Breakdown
Contributing Area SCS CN Area
acres Comments
On-Site Impervious 98 1.44 -
On-Site Open 74 1.03 Assume good condition
On-Site Wooded 70 0.00 Assume good condition
On-Site Water 100 0.00 -
Off-Site Impervious 98 0.00 -
Off-Site Open 74 0.01 Assume good condition
Off-Site Wooded 70 0.00 Assume good condition
Off-Site Water 100 0.00 -
Total area = 2.48 acres
0.0039 sq.mi.
Composite SCS CN = 88
•
B. Time of Concentration Information
Time of concentration is calculated using the SCS Segmental Approach (TR-55). Assumed minimum of 5 minutes.
Time of Concentration = 5.00 minutes
SCS Lag Time = 3.00 minutes (SCS Lag = 0.6* Tc)
Time Increment = 0.87 minutes (= 0.29*SCS Lag)
•
J.C. Diaz, El
4/4/2008
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Post-Development Hydrologic Calculations Page 4 of 8
Highway 29 Post-Development Hydrologic Calculations
GWH-06040 Subbasin I - To Pond 4
•
Cover Condition SCS CN Comments
Impervious 98 100%HSG'C' Soils
Open 74 100%HSG'C' Soils
Wooded 70 100%HSG'C' Soils
Water 100 100% HSG'C'Soils
A. Watershed Breakdown
Contributing Area SCS CN Area
acres Comments
On-Site Impervious 98 4.28 -
On-Site Open 74 1.81 Assume good condition
On-Site Wooded 70 0.00 Assume good condition
On-Site Water 100 0.00 -
Off-Site Impervious 98 0.00 -
Off-Site Open 74 0.17 Assume good condition
Off-Site Wooded 70 0.00 Assume good condition
Off-Site Water 100 0.00 -
Total area = 6.26 acres
0.0098 sq.mi.
Composite SCS CN = 90
• B. Time of Concentration Information
Time of concentration is calculated using the SCS Segmental Approach (TR-55). Assumed minimum of 5 minutes.
•
Time of Concentration = 5.00 minutes
SCS Lag Time = 3.00 minutes (SCS Lag = 0.6* Tc)
Time Increment = 0.87 minutes (= 0.29*SCS Lag)
J.C. Diaz, El
4/4/2008
X:\Projects\GWH\GWH-06040\Storm\Construction DrawingsWesign Files\Post-Development Hydrologic Calculations Page 5 of 8
Highway 29 Post-Development Hydrologic Calculations J.C. Diaz, El
GWH-06040 Subbasin I - Bypass to Reach 4/4/2008
0 MMUMMMMM
Cover Condition SCS CN Comments
Impervious 98 100% HSG'C'Soils
Open 74 100%HSG'C' Soils
Wooded 70 100% HSG'C'Soils
Water 100 100% HSG 'C' Soils

A. Watershed Breakdown
Contributing Area SCS CN Area
acres Comments
On-Site Impervious 98 0.00 -
On-Site Open 74 9.96 Assume good condition
On-Site Wooded 70 0.00 Assume good condition
On-Site Water 100 0.00 -
Off-Site Impervious 98 0.00 -
Off-Site Open 74 0.00 Assume good condition
Off-Site Wooded 70 0.00 Assume good condition
Off-Site Water 100 0.00 -
Total area = 9.96 acres
0.0156 sq.mi.
Composite SCS CN = 74
B. Time of Concentration Information
Time of concentration is calculated using the SCS Segmental Approach (TR-55). Assumed minimum of 5 minutes.
Time of Concentration = 5.00 minutes
SCS Lag Time = 3.00 minutes (SCS Lag = 0.6* Tc)
Time Increment = 0.87 minutes (= 0.29*SCS Lag)
•
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Post-Development Hydrologic Calculations Page 6 of 8
Highway 29 Post-Development Hydrologic Calculations J.C. Diaz, El
GWH-06040 Subbasin I - Bypass 4/4/2008
• "munnaffimminy
Cover Condition SCS CN Comments
Impervious 98 100%HSG'C' Soils
Open 74 100%HSG'C' Soils
Wooded 70 100% HSG'C'Soils
Water 100 100%HSG'C' Soils
A. Watershed Breakdown
Contributing Area SCS CN Area
acres Comments
On-Site Impervious 98 0.03 -
On-Site Open 74 5.35 Assume good condition
On-Site Wooded 70 0.00 Assume good condition
On-Site Water 100 0.00 -
Off-Site Impervious 98 0.00 -
Off-Site Open 74 0.00 Assume good condition
Off-Site Wooded 70 0.00 Assume good condition
Off-Site Water 100 0.00 -
Total area = 5.38 acres
0.0084 sq.mi.
Composite SCS CN = 74
• B. Time of Concentration Information
Time of concentration is calculated using the SCS Segmental Approach (TR-55). Assumed minimum of 5 minutes.
Time of Concentration = 5.00 minutes
SCS Lag Time = 3.00 minutes (SCS Lag = 0.6* Tc)
Time Increment = 0.87 minutes (= 0.29*SCS Lag)
•
X:\Projects\GWI-I\GWH-06040\Storm\Construction Drawings\Design Piles\Post-Development Hydrologic Calculations Page 7 of 8
Highway 29 Post-Development Hydrologic Calculations
GWH-06040 Reach
J.C. Diaz, El
4/4/2008
0
Length = 1379 ft Begin EL. 594.Oft
Slope = 0.0116 ft/ft End EL. 578.Oft
Manning's n = 0.045 natural stream
Flow Area = 25.00 sf (Assume 3'x3' channel)
Wetted Perimeter = 15.00 ft (Assume 3'x3' channel)
Channel Velocity= 5.01 ft/sec

Segment Time = 4.58 minutes
TOTAL TRAVEL TIME = 4.58 MINUTES
•
•
X:\Projects\GWH\GWH-06040\Storm\Construction Drawings\Design Files\Post-Development Hydrologic Calculations Page 8 of 9