20011549 Ver 1_Stormwater Info_20020814

WITHERS & RAVENEL
ENGINEERS I PLANNERS I SURVEYORS
vii MacKenan Drive
CARY, NORTH CAROLINA, 27511
[phone]
FAX [phone]oo8
To: NC DIVISION OF WATER QUALITY
4o1 WETLANDS UNIT
2321 CRABTREE BLVD, SUITE 250
RALEIGH, NC 276o4
WE ARE SENDING YOU
? Shop Drawings
? Copy of Letter
® Attached
? Prints
? Change order
COPIES DATE NO. DESCRIPTION
1 8/9/02 COVER LETTER
1 8/9/01 STORM WATER MANAGEMENT PLAN
1 8/12/02 0&M AGREEMENT

i i i i
THESE ARE TRANSMITTED as checked below:
? For approval ? Approved as submitted
? For your use ? Approved as noted
? As requested ? Returned for corrections
? For review and comment ?
? FOR BIDS DUE 20 ? PRINTS RETURNED AFTER LOAN TO US
REMARKS:
COPY TO: FILE SIGNED: KEN JESNECK, PE
if enclosures are not as noted, kindly notify us at once.
? Resubmit
? Submit
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copies for approval
copies for distribution
corrected prints
LETTER OF T° ° NSWTTAL
DATE 8/14/02 JOB No. 201113.0
ATTENTJON TODD ST JOHN
PHONE # [phone]
RE: LONG LAKE SUBDIVISION
DWQ PERMIM ol-i549

s
`
a
il
s:
? Under separate cover via j R-rr
TIOIU
® Plans ? Samples ? Specifications
? Diskette ?
WITHERS RAVEN EL
ENGINEERS I PLANNERS I SURVEYORS
August 14, 2002
Mr. Todd St. John
North Carolina Department of Environment and Natural Resources
Division of Water Quality
2321 Crabtree Boulevard
Raleigh, North Carolina 27604-226o
Re: Storm Water Management Plan
Long Lake Subdivision
DWQ Project Number 01-1549
W&R Project 201113.0
Mr. St. John:
Please find the attached Storm Water Management Plan, Phases 2 and 3, for the Long Lake
Subdivision. This submittal is in response to the conditions of the April 18, 2002, 401 Water Quality
Certification, Additional Conditions. The plans, Operation and Maintenance Agreement, and
supporting calculations are included with this submittal f% --structural management practices. The
overall phasing plan has been revised so that the structures match the identification system
imposed by the City of Raleigh for their stormwater management program.
Several modifications to the phasing plan as presented in the previous submittal are incorporated
into this submittal. The first change includes the splitting of the constructed wetlands in Tract 1 into
two smaller constructed wetlands. This change resulted from the City of Raleigh not allowing any
grading within their greenway easement. The revised wetland configuration (Pond A) and the new
constructed wetland (Pond C) will replace the original wetland previously approved. The other two
structural devices in this submittal are those described in the correspondence dated April 2, 2002.
No changes are being proposed to Phases 3, 4, or 5 at this time. Phase 6 remains basically the
same, except that one of the structural devices will be placed in Tract 7. All the preliminary design
data will remain the same. A Phase 7 has been added due to the addition of anther tract within the
overall development.` The Phase 7 device will be a dry detention pond designed to capture the first
runoff from the first inch of precipitation and releasing the detained water over 48 to 96 hours
through the 50 foot Neuse River Buffer.
We trust that attached plans will be sufficient to complete the review and approval of the Phases 2
and 3 Storm Water Management Plan provided for this site. Please advise should you have any
questions or comments.
INC.
K:\oi\o1-110\01113\DWQ-POND S\081402.TST.doc
\ 111 MacKenan Drive i Cary, North Carolina 27511 1 tel: [phone] fax: [phone]oo8 i www.withersravenel.com
Sincerely,

LONG LAKE SUBDIVISION
POND A - TRACT 1, PHASE 1
OPERATION AND MAINTENANCE AGREEMENT
The constructed wetland basin system is defined as the wetland basin, pretreatment including forebays and
the vegetated filter if one is provided.
Maintenance activities shall be performed as follows:
1. After every significant runoff producing rainfall event and at least monthly:
a. Inspect the wetland detention basin system for sediment accumulation, erosion, trash accumulation,
vegetated cover, and general condition.
b. Check and clear the orifice on the skimmer 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 wetland detention basin system semi-annually or when depth is
reduced to what is shown in the 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 wetland 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 accumulated sediment depth reads 0.5 feet in the main pond, the sediment shall be removed.
If the elevation of the marsh areas exceeds the permanent pool elevation, the sediment should be
removed to design levels. This shall be accomplished by removing and stockpiling the upper 6 inches of
soil. Then the marsh area shall be excavated six inches below design elevations. Afterwards, the
stockpiled soil should be spread over the marsh surface. The soil should not be stockpiled for more than
two weeks.
When the accumulated sediment depth reads 1.0 feet in the forebay and micro-pool, the sediment shall be
removed.
CONSTRUCTED WETLAND DIAGRAM
V Permanent (Normal) Pool Elevation 390'
Sediment 7evaov al El . 389'
___ Sediment Removal Elevation 389'
n 388' ------ ---------------------------------'
Bottom tio I
Bottom Elevation
FOREBAY & MICRO-POOL MAIN POND
Page 1 of 2
LONG LAKE SUBDIVISION
POND C - TRACT 1, PHASES 3 & 4
OPERATION AND MAINTENANCE AGREEMENT
5. Wetland planting densities in the marsh areas should be maintained by replanting bare areas as
needed. Wetland plants should be encouraged to grow in the marsh areas.
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.
7. All components of the wetland detention basin system shall be maintained in good working order.
8. Level spreaders or other structures that provide diff use flow shall be maintained every six months. All
accumulated sediment and debris shall be removed from the structure, and a level elevation shall be
maintained across the entire flow spreading structure. Any down gradient erosion must be repaired and/or
replanted as necessary.
I acknowledge and agree by my signature below that I am responsible for the performance of the eight
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: A L At4 C ? VOu-
Title: e-? 2 v l_A N
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, z:- &" Gv v??" , a Notary Public for the State of ALA Cary /'4 t ,
County of do hereby certify that tin r?
personally appeared before me this day of +? c u.,?L and acknowledge the due
execution of the forgoing wet [wetland] detention basin maintenance requirements. Witness my hand and
official seal,
.?`%EN L®1,•F•`'
i14 0 TA?
all
A'11i
?? ?F?. mss
C0UN'T%( '
11100 %%
SEAL
My commission expires --2 7- 0
Page 2 of 2
Address: Pulte Home Corporation 401 Harrison Oaks Blvd, Ste 250 Cary, NC 27513
.. f-
LONG LAKE SUBDIVISION
POND C - TRACT 1, PHASES 3 & 4
OPERATION AND MAINTENANCE AGREEMENT
The constructed wetland basin system is defined as the wetland basin, pretreatment including forebays and
the vegetated filter if one is provided.
Maintenance activities shall be performed as follows:
1. After every significant runoff producing rainfall event and at least monthly:
a. Inspect the wetland detention basin system for sediment accumulation, erosion, trash accumulation,
vegetated cover, and general condition.
b. Check and clear the orifice on the skimmer 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 wetland detention basin system semi-annually or when depth is
reduced to what is shown in the 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 wetland 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 accumulated sediment depth reads 0.5 feet in the main pond, the sediment shall be removed.
If the elevation of the marsh areas exceeds the permanent pool elevation, the sediment should be
removed to design levels. This shall be accomplished by removing and stockpiling the upper 6 inches of
soil. Then the marsh area shall be excavated six inches below design elevations. Afterwards, the
stockpiled soil should be spread over the marsh surface. The soil should not be stockpiled for more than
two weeks.
When the accumulated sediment depth reads 1.0 feet in the forebay and micro-pool, the sediment shall be
removed.
CONSTRUCTED WETLAND DIAGRAM
0 Permanent (Normal) Pool Elevation 396'
Sediment 7evaov al El . 395' ,?
__r_ Sediment Removal Elevation 395'
Bottom tion 394' _----- _
ion 394.5' 1
FOREBAY & MICRO-POOL
MAIN POND
Page 1 of 2
i
WO .. V,
LONG LAKE SUBDIVISION
POND A - TRACT 1, PHASE 1
OPERATION AND MAINTENANCE AGREEMENT
5. Wetland planting densities in the marsh areas should be maintained by replanting bare areas as
needed. Wetland plants should be encouraged to grow in the marsh areas.
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.
7. All components of the wetland detention basin system shall be maintained in good working order.
8. Level spreaders or other structures that provide diffuse flow shall be maintained every six months. All
accumulated sediment and debris shall be removed from the structure, and a level elevation shall be
maintained across the entire flow spreading structure. Any down gradient erosion must be repaired and/or
replanted as necessary.
I acknowledge and agree by my signature below that I am responsible for the performance of the eight
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: A l," 'c-'- ?rl U-
Title: '?:>c P- of LA(Ij
Address: Pulte Home Corporation 401 Harrison Oaks Blvd, Ste 250 Cary, NC 27513
Phor
Sign,
Date
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, '?-- ; le, Z 14L , a Notary Public for the State of "U,
County of yu k , do hereby certify that Cll r'r C # ??
personally appeared before me this day of QL S uJf , .Z 00 d- , and acknowledge the due
execution of the forgoing wet [wetland] detention basin maintenance requirements. Witness my hand and
official seal,
fte 0,
C
'c
,UAW1 ?
SEAL
My commission expires 1-2 --2 7 - "?
Page 2of2
LONG LAKE SUBDIVISION
POND D - TRACT 1, PHASE 2
OPERATION AND MAINTENANCE AGREEMENT
5. Remove cattails and other indigenous wetland plants when they cover 50% of the basin surface
6. All components of the dry detention basin system shall be maintained in good working order.
7. Level spreaders or other structures that provide diffuse flow shall be maintained every six months. All
accumulated sediment and debris shall be removed from the structure, and a level elevation shall be
maintained across the entire flow spreading structure. Any down gradient erosion must be repaired and/or
replanted as necessary.
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 Tr responsible party.
Print name: " A L W C- I t,l,
dlp?
Address: Pulte Home Corporation 401 Harrison Oaks Blvd, Ste 250 Cary, NC 27513
Phor
Sign,
Date
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 Public for the State of
County of w, Y( <-- , do hereby certify that Al., C ,9: ??
personally appeared before me this day of o oa- , and acknowledge the due
execution of the forgoing wet [wetland] detention basin maintenance requirements. Witness my hand and
official seal,
o.
ys pUBtIC
??''' • N•.•e••*-
.??p
0 U N 11
SEAL
My commission expires L I) -,1 7- o y
Page 2 of 2
LONG LAKE SUBDIVISION
POND D - TRACT 1, PHASE 2
OPERATION AND MAINTENANCE AGREEMENT
The extended dry detention basin system is defined as the dry detention basin, pre-treatment including
forebays and the vegetated filter if one is provided.
Maintenance activities shall be performed as follows:
After every significant runoff producing rainfall event and at least monthly:
a. Inspect the dry detention basin system for sediment accumulation, erosion, trash accumulation,
vegetated cover, and general condition.
b. Check and clear the orifice on the skimmer 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 dry 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 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.
When the sediment depth reads 1 ft in the main pond, the sediment shall be removed.
When the sediment depth reads 1 ft in the forebay, the sediment shall be removed.
BASIN DIAGRAM
Top of Dam Elevation 386.5 ft
Riser Crest Elevation 384.4 ft
Sediment Removal El. 382 ft
---- ---_-____ Sediment Removal Elevation 382 ft 75%
Bottom Ele tion 381 ft --------------------------------------------- -----
Bottom Elevation
FOREBAY
MAIN POND
25
Page 1 of 2

LONG LAKE SUBDIVISION
POND E - TRACT 2, PHASE 2
OPERATION AND MAINTENANCE AGREEMENT
The constructed wetland basin system is defined as the wetland basin, pretreatment including forebays and
the vegetated filter if one is provided.
Maintenance activities shall be performed as follows:
After every significant runoff producing rainfall event and at least monthly:
a. Inspect the wetland detention basin system for sediment accumulation, erosion, trash accumulation,
vegetated cover, and general condition.
b. Check and clear the orifice on the skimmer 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 wetland detention basin system semi-annually or when depth is
reduced to what is shown in the 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 wetland 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 accumulated sediment depth reads 0.5 feet in the main pond, the sediment shall be removed.
If the elevation of the marsh areas exceeds the permanent pool elevation, the sediment should be
removed to design levels. This shall be accomplished by removing and stockpiling the upper 6 inches of
soil. Then the marsh area shall be excavated six inches below design elevations. Afterwards, the
stockpiled soil should be spread over the marsh surface. The soil should not be stockpiled for more than
two weeks.
When the accumulated sediment depth reads 1.0 feet in the forebay and micro-pool, the sediment shall be
removed.
CONSTRUCTED WETLAND DIAGRAM
V Permanent (Normal) Pool Elevation 384.25'
Sediment Re oval El. 383'
--------------- - Sediment Removal Elevation 383.25'
Bottom El vation 382' --------------------------------------------- *-----
FOREBAY & MICRO-POOL
E
MAIN POND
Page 1 of 2

LONG LAKE SUBDIVISION
POND E - TRACT 2, PHASE 2
OPERATION AND MAINTENANCE AGREEMENT
5. Wetland planting densities in the marsh areas should be maintained by replanting bare areas as
needed. Wetland plants should be encouraged to grow in the marsh areas.
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.
7. All components of the wetland detention basin system shall be maintained in good working order.
8. Level spreaders or other structures that provide diff use flow shall be maintained every six months. All
accumulated sediment and debris shall be removed from the structure, and a level elevation shall be
maintained across the entire flow spreading structure. Any down gradient erosion must be repaired and/or
replanted as necessary.
I acknowledge and agree by my signature below that I am responsible for the performance of the eight
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: t / 1 UA fj ?- tr1? 1. L
ra 2.
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, _6; ee" zo „I? , a Notary Public for the State of ko, Ill r"'u
County of (Jo, do hereby certify that , Nn L g ly
personally appeared before me this _ day of 14 yJ 2 0()0- , and acknowledge the due
execution of the forgoing wet [wetland] detention basin maintenance requirements. Witness my hand and
official seal,
0 .M•••'•
TAN
y
i
y • V?I.IC
C D UNS(
SEAL
My commission expires jj -2 7- 0
Page 2 of 2
Address: Pulte_Home Corporation 401 Harrison Oaks Blvd, Ste 250 Cary, NC 27513
Project Name: Long Lake
Project No. DW Q
pond C
SUBMITTED DESIGN: REQUIRED DESIGN.
elevations 2.3 average depth status
Bottom of Basin (ft)
Permanent Pool (ft) ' 396 396 ft. depth check depth
Temporary Pool (ft) 398 2 ft. depth ok

areas
Permanent Pool SA (sq ft) 5342 5195 sq. ft. ok
Drainage Area (ac) 7.52
Impervious Area (ac) 2.73 36.3 % -
Forebay (ft2) 0% check forebt
Low Marsh (ft2) 0.0% check mars{
Micropool (ft2) 0% check forebi
High Marsh (ft2) 0.0% check marsl
0%
volumes
Temporary Pool (cu ft) 12232 0 cu. ft. ok
other parameters
SA/DA 1.59 -
Orifice Diameter (in) 0.00 cfs drawdown -
Design Rainfall (in) #DIV/0! day drawdown #DIV/0!
Linear Interpolation of Correct SAIDA***
396 ft. Permanent Pool Depth
% Impervious SA/DA from Table
Next Lowest 30 1.34
Project Impervious 36.3 1.59
Next Highest 40 1.73
WITHERS & RAVENEL
J PHASES 2 AND 3 OF THE
STORMWATER MANAGEMENT PLAN
SUPPORTING DESIGN CALCULATIONS
LONG LAKE SUBDIVISION
Raleigh, North Carolina
Prepared For:
PULTE HOME CORPORATION
4o1 Harrison Oaks Boulevard, Suite 250
Cary, North Carolina 27513
Prepared By:
WITHERS & RAVENEL, INC
iii MacKenan Drive
Cary, North Carolina 27511
August 2002
?,••' (? CARD j
W&R Project No. 201113 j'iStpjp'?•p?
18
f
Kenneth? °
,dd?dd pr?e S}?'
??bbe
V,
POND A
Long Lake Subdivision
Tract s
Protect Name: Long Lake Subdivision - Tract 1
City/State: Raleigh, NC
Project #: 201113.2
Date: 14-Aug-02
Table 1.1 Surface Area to Drainage Area Ratio for Permanent Pool Sizing for 85% Pollutant
Rmmnval FffiriPnrv in the Pipdmnnt
% Impervious
Cover Permanent Pool Dept
3.0 4.0 5.0 6.0 h (feet)
7.0 8.0 9.0
10 0.59 0.49 0.43 0.35 0.31 0.29 0.26
20 0.97 0.79 0.70 0.59 0.51 0.46 0.44
30 1.34 1.08 0.97 0.83 0.70 0.64 0.62
40 1.73 1.43 1.25 1.05 0.90 0.82 0.77
50 2.06 1.73 1.50 1.30 1.09 1.00 0.92
60 2.40 2.03 1.71 1.51 1.29 1.18 1.10
70 2.88 2.40 2.07 1.79 1.54 1.35 1.26
80 3.36 2.78 2.38 2.10 1.86 1.60 1.42
90 3.74 3.10 2.66 2.34 2.11 1.83 1.67
Source: NCDENR/DWQ Stormwater Best Management Practices, pg. 5, April 1999
POND A (Constructed Wetland)
Pervious
(ac) Impervious
(ac) Total
Area (ac)
Pervious Area 6.17 0 6.17
Impervious 0 6.05 6.05
Totals 6.17 6.05 12.22
% Impervious Surface Area =
Surface Area of Permanent Pool:
49.5 %
Assumed depth = 3 feet
SA/DA ratio = 2.04 % From Table 1.1
Minimum pond surface area (SA) _ (DA * SA/DA ratio)/100
SA = 0.250 acres
10878 sq. ft.
Normal pool elevation = 390 feet
Surface area provided = 0.25 acres
10890 sq. ft.
1-Inch Runoff Volume Calculation
Using the runoff volume calculations in the "Simple Method" as described by Schueler (1987)
Rv = 0.05 + 0.009(1) where, Rv = Runoff coefficient, in./in.
I = Percent impervious
Rv = 0.496 in./in.
Total runoff volume from 1-inch precipitation:
Runoff volume, S = (Design rainfall) (Rv) (Drainage Area)
S = 0.505 acre-ft
21983 cu. ft.
Elevation for required storage = 391.76'
Runoff storage provided = 0.505 ac-ft
Riser structure crest elevation = 392 feet
Runoff storage provided = 0.579 ac-ft
25221 cu. ft.
0\01\01-110\01113\HH\SWMP\Pulte Stormwater Calcs Wetlands jun02.xls
LONG LAKE SUBDIVISION - TRACT 1
POND A - PONDPACK OUTPUT FOR WETLAND DESIGN
Job File: K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND A_TRACTI-WETLAND.PPW
Rain Dir: I:\ENGFILE\HAESTAD\PPW RAINFALL DATA\WAKE CO\
--------------------------
--------------------------
JOB TITLE
--------------------------
--------------------------
LONG LAKE SUBDIVISION - TRACT 1
POND A - Extended Detention Wetland
Raleigh, North Carolina
W&R Project #201113.2
The Modified Rational Method was used to determine peak discharge rates for the 2-year,
10-year and 100-year design storm events for the Raleigh/Durham, North Carolina area and
size the detention storage for the dry detention pond due to the small drainage area
(±12.2 acres). The Modified Rational Method is an extension of the rational method for
rainfalls with durations greater than the time of concentration. The method was modified
so that the concepts of the rational method (peak discharge) could be used to develop
hydrographs for storage routing. The Modified Rational Method within PondPack calculates
the storage volume for hydrographs of rainfalls of various durations to determine the
critical duration for the design storm as the one requiring the greatest detention
storage volume. This critical duration is used to calculate the discharge rate and
volume of water that is routed through the pond structure. The hydrograph developed
maintains the calculated volume and adjusts the peak discharge rate accordingly. Thus,
the peak discharge for the Modified Rational Method is less than the calculated Rational
Method.
The rainfall data used in this design was taken from the Intensity-Duration-Frequency
Table for the Raleigh area published in the City of Raleigh Stormwater Management Design
Manual. The post-development time of concentration was set at 5 minutes to account for
the piped drainage system.
Pond A is an extended detention wetland that is designed to capture the volume of runoff
from the first 1-inch of rainfall and slowly release it over a 48 to 72 hour period. In
addition, the wetland is designed to pass the 100-year design storm through the
riser/barrel outlet structure of the pond.
Pond A Design Highlights:
Normal Pool Elevation = 390'
Required Surface Area = 0.250 acres (10,878 sq. ft.)
Surface Area Provided = 0.251 acres (10,940 sq. ft.)
Required Storage Volume = 0.505 ac-ft
Storage Volume Provided = 0.579 ac-ft at 392'
Top of Dam = 395'
Calculated Freeboard for the 10-yr design storm = 2.39 ft
Calculated Freeboard for the 100-yr design storm = 2.29 ft
Outlet Structure:
• 48" RCP Riser structure with crest at 392'
¦ 24" RCP Barrel; 32 linear feet; Inverts at 386.64' and 386'
¦ 2.5" Circular Orifice at 390' for extended draw-down
LONG LAKE SUBDIVISION - TRACT 1
POND A - PONDPACK OUTPUT FOR WETLAND DESIGN
Table of Contents
********************r* MASTER SUMMARY t***********rt****r*t*
Watershed....... Mod. Rational Grand Summary ........ 1.01
Master Network Summary ............. 1.02
********************** RAINFALL DATA ***********************
2-yr IDF Table.. 2-yr
I-D-F Table ........................ 2.01
10-yr IDF Table 10-yr
I-D-F Table ........................ 2.01
100-yr IDF Table 100-yr
I-D-F Table ........................ 2.02
********************** TC CALCULATIONS *********************
AREA POND A..... Tc Calcs ........................... 3.01
*********************** POND VOLUMES ***********************
POND A.......... Vol: Elev-Area ..................... 4.01
******************** OUTLET STRUCTURES *********************
OUTLET.......... Outlet Input Data .................. 5.01
Composite Rating Curve ............. 5.04
*********************** POND ROUTING ***********************
POND A.......... Pond E-V-Q Table ................... 6.01
****************** RATIONAL METHOD CALCS *******************
AREA POND A..... C and Area ......................... 7.01
AREA POND A..... Rational Peak Qs ................... 7.02
AREA POND A..... 2-yr Mod. Rational Storm Calcs ..... 7.03
AREA POND A..... 10-yr Mod. Rational Storm Calcs .... 7.04
AREA POND A..... 100-yr Mod. Rational Storm Calcs ... 7.05
LONG LAKE SUBDIVISION - TRACT 1
POND A - PONDPACK OUTPUT FOR WETLAND DESIGN
Type.... Mod. Rational Grand Summary Page 1.01
Name.... Watershed
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND A_TRACTI_WETLAND.PPW
************************************************************************
************************************************************************
*
*
* MODIFIED RATIONAL METHOD
* ---- Grand Summary For All Storm Frequencies ----
*
*
************************************************************************
************************************************************************
Q = CiA * Units Conversion; Where Conversion = 43560 / (12 * 3600)

..... Area =
......... 12.220 acres
............
....... Tc
............. = .0833
......... hrs
..........
...........
................ ......... ............ ....... ............. ...................
VOLUMES
Freq. Adjusted Duration I Qpeak Allowable Inflow Storage
years 'CT
---------------- hrs
--------- in/hr
------------ cfs
------- cfs I
---------- -- ac-ft
--------- ac-ft
----------
2 .597 .7167 2.1783 16.01 10.00 .948 .618
10 .597 .9167 2.5597 18.82 13.00 I 1.426 .888
100 .597 1.1500 3.2090 23.59 14.00 2.242 1.529
LONG LAKE SUBDIVISION - TRACT 1
POND A - PONDPACK OUTPUT FOR WETLAND DESIGN
Type.... Master Network Summary Page 1.02
Name.... Watershed
File.... K:\01\01-110\01113\H&H\SWMP\PPW WETLANDS\POND A TRACTI WETLAND.PPW
MASTER DESIGN STORM SUMMARY
Default Network Design Storm File, ID RAL_IDF.IDQ Raleigh IDF
Rainfall
Return Event Type IDF File IDF ID
------------
2-yr ---------------
I-D-F Table -------- --
RAL IDF ------
2-yr I --------
DF Table
10-yr I-D-F Table RAL_IDF 10-yr IDF Table
100-yr I-D-F Table RAL_IDF 100-yr IDF Table
MASTER NETWORK SUMMARY
Modified Rational Me thod Network
(*Node=Outfall; +Node =Diversion;)
(Trun= HYG Truncation: Blank=None; L=Left; R=Rt; LR=L eft&Rt)
Max
Return HYG Vol Qpeak Qpeak Max WSEL Pond Storage
Node ID Type Event ac-ft Trun hrs cfs ft ac-ft
----------------- ----
AREA POND A AREA ------ ---------- --
2 .948 --------- -
.0833 -------
16.01 -------- ------------
AREA POND A AREA 10 1.425 .0833 18.82
AREA POND A AREA 100 2.242 .0833 23.59
*OUTFALL JCT 2 .661 .7300 13.67
*OUTFALL JCT 10 1.135 .9100 18.68
*OUTFALL JCT 100 1.948 1.0900 23.59
POND A IN POND 2 .948 .0900 16.01
POND A IN POND 10 1.425 .0900 18.82
POND A IN POND 100 2.241 .0900 23.59
POND A OUT POND 2 .661 .7300 13.67 392.49 .738
POND A OUT POND 10 1.135 .9100 18.68 392.61 .777
POND A OUT POND 100 1.948 1.0900 23.59 392.71 .811
LONG LAKE SUBDIVISION - TRACT 1
POND A - PONDPACK OUTPUT FOR WETLAND DESIGN
Type.... I-D-F Table Page 2.01
Name.... 2-yr IDF Table Tag: 2-yr Event: 2 yr
File.... I:\ENGFILE\HAESTAD\PPW RAINFALL DATA\WAKE CO\RAL_IDF.IDF
Title... 2-yr Storm from City of Raleigh IDF Table
Storm... 2-yr IDF Table Tag: 2-yr
Rainfall-Intensity-Duration Curve
Time, hrs Intens., in/hr
.0833
.1670
.2500
.3330
.5000
.6670
.8330
1.0000
1.5000
2.0000
3.0000
6.0000
12.0000
24.0000
5.7600
4.7600
4.0400
3.4700
2.7000
2.2800
1.9400
1.7000
1.2200
.9500
.7100
.4400
.2600
.1500
Type.... I-D-F Table
Name.... 10-yr IDF Table Tag: 10-yr Event: 10 yr
File.... I:\ENGFILE\HAESTAD\PPW RAINFALL DATA\WAKE CO\RAL_IDF.IDF
Title... 10-yr Event Table from City of Raleigh IDF Table
Storm... 10-yr IDF Table Tag: 10-yr
Rainfall-Intensity-Duration Curve
Time, hrs Intens., in/hr
.0833 7.5000
.1670 6.1300
.2500 5.2500
.3300 4.6400
.5000 3.7100
.6670 3.1500
.8330 2.7100
1.0000 2.4100
1.5000 1.7400
2.0000 1.3700
3.0000 1.0200
6.0000 .6500
12.0000 .3900
24.0000 .2200
LONG LAKE SUBDIVISION - TRACT 1
POND A - PONDPACK OUTPUT FOR WETLAND DESIGN
Type.... I-D-F Table Page 2.02
Name.... 100-yr IDF Table Tag: 100-yr Event: 100 yr
File.... I:\ENGFILE\HAESTAD\PPW RAINFALL DATA\WAKE CO\RAL_IDF.IDF
Title... 100-yr Event from City of Raleigh IDF Table
Storm... 100-yr IDF Table Tag: 100-yr
Rainfall-Intensity-Duration Curve
Time, hrs Intens., in/hr
.0833
.1670
.2500
.3330
.5000
.6670
.8330
1.0000
1.5000
2.0000
3.0000
6.0000
12.0000
24.0000
9.7200
8.4000
7.2400
6.4700
5.2800
4.4800
3.8800
3.5000
2.5300
2.0000
1.5000
.9600
.5700
.3300
LONG LAKE SUBDIVISION - TRACT 1
POND A - PONDPACK OUTPUT FOR WETLAND DESIGN
Type.... Tc Calcs
Name.... AREA POND A
Page 3.01
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND A_TRACTI_WETLAND.PPW
........................................................................
........................................................................
TIME OF CONCENTRATION CALCULATOR
........................................................................
........................................................................
Segment #1: Tc: User Defined
Description: Tc = 5 minutes
Segment #1 Time: .0833 hrs
------------------------------------------------------------------------
-------------------------
-------------------------
Total Tc: .0833 hrs
Calculated Tc < Min.Tc:
Use Minimum Tc...
Use Tc = .0833 hrs
-------------------------
-------------------------
LONG LAKE SUBDIVISION - TRACT 1
POND A - PONDPACK OUTPUT FOR WETLAND DESIGN
Type.... Vol: Elev-Area
Name.... POND A
Page 4.01
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND A TRACTI_WETLAND.PPW
Elevation Planimeter Area Al+A2+sgr(Al*A2) Volume Volume Sum
(ft) (sq.in) (acres)
----------- (acres)
----------------- (ac-ft)
--------- (ac-ft)
-------------
-----------
390.00 -----------
----- .2500 .0000 .000 .000
391.00 ----- .2950 .8166 .272 .272
392.00 ----- .3190 .9208 .307 .579
393.00 ----- .3420 .9913 .330 .910
394.00 ----- .3900 1.0972 .366 1.275
395.00 .4260 1.2236 .408 1.683
POND VOLUME EQUATIONS
* Incremental volume computed by the Conic Method for Reservoir Volumes.
Volume = (1/3) * (EL2-EL1) * (Areal + Area2 + sq.rt.(Areal*Area2))
where: ELI, EL2 = Lower and upper elevations of the increment
Areal,Area2 = Areas computed for ELI, EL2, respectively
Volume = Incremental volume between ELI and EL2
LONG LAKE SUBDIVISION - TRACT 1
POND A - PONDPACK OUTPUT FOR WETLAND DESIGN
Type.... Outlet Input Data
Name.... OUTLET
Page 5.01
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND A_TRACTI_WETLAND.PPW
REQUESTED POND WS ELEVATIONS:
Min. Elev.= 390.00 ft
Increment = .10 ft
Max. Elev.= 395.00 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
Stand Pipe RI ---> CV 392.000 395.000
Orifice-Circular OR ---> CV 390.000 395.000
Culvert-Circular CV ---> TW 386.640 395.000
TW SETUP, DS Channel
LONG LAKE SUBDIVISION - TRACT 1
POND A - PONDPACK OUTPUT FOR WETLAND DESIGN
Type.... Outlet Input Data
Name.... OUTLET
Page 5.02
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND A_TRACTI_WETLAND.PPW
OUTLET STRUCTURE INPUT DATA
Structure ID = RI
Structure Type = Stand Pipe
-----------------
# of openings -------------
= 1 ------
Invert Elev. = 392.00 ft
Diameter = 4.0000 ft
Orifice Area = 12.5664 sq.ft
Orifice Coeff. _ .600
Weir Length = 12.57 ft
Weir Coeff. = 3.100
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. = 390.00 ft
Diameter = .2083 ft
Orifice Coeff. _ .600
LONG LAKE SUBDIVISION - TRACT 1
POND A - PONDPACK OUTPUT FOR WETLAND DESIGN
Type.... Outlet Input Data Page 5.03
Name.... OUTLET
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND A TRACTI_WETLAND.PPW
OUTLET STRUCTURE INPUT DATA
Structure ID = CV
Structure Type = Culvert-Circular
-----------------
No. Barrels -------------
= 1 ------
Barrel Diameter = 2.0000 ft
Upstream Invert = 386.64 ft
Dnstream Invert = 386.00 ft
Horiz. Length = 32.00 ft
Barrel Length = 32.01 ft
Barrel Slope = .02000 ft/ft
OUTLET CONTROL DATA...
Mannings n = .0130
Ke = .5000
Kb = .012411
Kr = .5000
HW Convergence = .001
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) = 1.150
T2 ratio (HW/D) = 1.297
Slope Factor = -.500
(forward entrance loss)
(per ft of full flow)
(reverse entrance loss)
+/- ft
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 = 388.94 ft ---> Flow = 15.55 cfs
At T2 Elev = 389.23 ft ---> Flow = 17.77 cfs
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
LONG LAKE SUBDIVISION - TRACT 1
POND A - PONDPACK OUTPUT FOR WETLAND DESIGN
Type.... Composite Rating Curve
Name.... OUTLET
Page 5.04
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND A_TRACTI_WETLAND.PPW
***** COMPOSITE OUTFLOW SUMMARY ****
WS Elev, Total Q Notes
-------- -------- ------ -- Converge ------- ---- --- -----------
Elev. Q TW El ev Error
ft cfs ft +/-ft Contributing Structures
-
--------
390.00 -------
.00 ------
Free -- -----
Outfall --------
(no Q: -----------------
RI,OR,CV)
390.10 .01 Free Outfall OR,CV (no Q: RI)
390.20 .05 Free Outfall OR,CV (no Q: RI)
390.30 .07 Free Outfall OR,CV (no Q: RI)
390.40 .09 Free Outfall OR,CV (no Q: RI)
390.50 .10 Free Outfall OR,CV (no Q: RI)
390.60 .12 Free Outfall OR,CV (no Q: RI)
390.70 .13 Free Outfall OR,CV (no Q: RI)
390.80 .14 Free Outfall OR,CV (no Q: RI)
390.90 .15 Free Outfall OR,CV (no Q: RI)
391.00 .16 Free Outfall OR,CV (no Q: RI)
391.10 .16 Free Outfall OR,CV (no Q: RI)
391.20 .17 Free Outfall OR,CV (no Q: RI)
391.30 .18 Free Outfall OR,CV (no Q: RI)
391.40 .19 Free Outfall OR,CV (no Q: RI)
391.50 .19 Free Outfall OR,CV (no Q: RI)
391.60 .20 Free Outfall OR,CV (no Q: RI)
391.70 .21 Free Outfall OR,CV (no Q: RI)
391.80 .21 Free Outfall OR,CV (no Q: RI)
391.90 .22 Free Outfall OR,CV (no Q: RI)
392.00 .23 Free Outfall OR,CV (no Q: RI)
392.10 1.46 Free Outfall RI,OR,C V
392.20 3.72 Free Outfall RI,OR,C V
392.30 6.64 Free Outfall RI,OR,CV
392.40 10.10 Free Outfall RI,OR,C V
392.50 14.03 Free Outfall RI,OR,C V
392.60 18.36 Free Outfall RI,OR,CV
392.70 23.08 Free Outfall RI,OR,C V
392.80 28.09 Free Outfall RI,OR,CV
392.90 33.37 Free Outfall RI,CV (no Q: OR)
393.00 35.35 Free Outfall RI,CV (no Q: OR)
393.10 35.70 Free Outfall RI,CV (no Q: OR)
393.20 36.05 Free Outfall RI,CV (no Q: OR)
393.30 36.39 Free Outfall RI,CV (no Q: OR)
393.40 36.73 Free Outfall RI,CV (no Q: OR)
393.50 37.06 Free Outfall RI,CV (no Q: OR)
393.60 37.40 Free Outfall RI,CV (no Q: OR)
393.70 37.73 Free Outfall RI,CV (no Q: OR)
LONG LAKE SUBDIVISION - TRACT 1
POND A - PONDPACK OUTPUT FOR WETLAND DESIGN
Type.... Composite Rating Curve
Name.... OUTLET
Page 5.05
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND A_TRACTl_WETLAND.PPW
***** COMPOSITE OUTFLOW SUMMARY ****
WS Elev, Total Q
Elev. Q
ft cfs
--------
393.80 -------
38.06
393.90 38.38
394.00 38.70
394.10 39.02
394.20 39.34
394.30 39.65
394.40 39.96
394.50 40.27
394.60 40.58
394.70 40.88
394.80 41.19
394.90 41.48
395.00 41.78
Notes
------ -- Converge ------ ----- -- ------------
TW El ev Error
ft +/-ft Contributing Structures
------
Free -- -----
Outfall -------
RI,CV -----
(no --
Q: ------------
OR)
Free Outfall RI,CV (no Q: OR)
Free Outfall RI,CV (no Q: OR)
Free Outfall RI,CV (no Q: OR)
Free Outfall RI,CV (no Q: OR)
Free Outfall RI,CV (no Q: OR)
Free Outfall RI,CV (no Q: OR)
Free Outfall RI,CV (no Q: OR)
Free Outfall RI,CV (no Q: OR)
Free Outfall RI,CV (no Q: OR)
Free Outfall RI,CV (no Q: OR)
Free Outfall RI,CV (no Q: OR)
Free Outfall RI,CV (no Q: OR)
LONG LAKE SUBDIVISION - TRACT 1
POND A - PONDPACK OUTPUT FOR WETLAND DESIGN
Type.... Pond E-V-Q Table Page 6.01
Name.... POND A
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND A TRACTI_WETLAND.PPW
LEVEL POOL ROUTING DATA
HYG Dir = K:\01\01-110\01113\H&H\SWMP\PPW WETLANDS\
Inflow HYG file = NONE STORED - POND A IN 2-yr
Outflow HYG file = NONE STORED - POND A OUT 2-yr
Pond Node Data = POND A
Pond Volume Data = POND A
Pond Outlet Data = OUTLET
No Infiltration
INITIAL CONDITIONS
---------
Starting ------------
WS Elev = --------
390.00 -----
ft
Starting Volume = .000 ac-ft
Starting Outflow = .00 cfs
Starting Infiltr. _ .00 cfs
Starting Total Qout= .00 cfs
Time Increment = .0100 hrs
Elevation Outflow Storage Area Infilt. Q Total 2S/t + 0
ft cfs ac-ft acres cfs
---- cfs
------------ cfs
----------
-------------
390.00 ------------
.00 --------
.000 ------------
.2500 -------
.00 .00 .00
390.10 .01 .025 .2543 .00 .01 61.04
390.20 .05 .051 .2587 .00 .05 123.16
390.30 .07 .077 .2631 .00 .07 186.30
390.40 .09 .103 .2676 .00 .09 250.53
390.50 .10 .130 .2720 .00 .10 315.84
390.60 .12 .158 .2766 .00 .12 382.24
390.70 .13 .186 .2811 .00 .13 449.73
390.80 .14 .214 .2857 .00 .14 518.30
390.90 .15 .243 .2903 .00 .15 588.02
391.00 .16 .272 .2950 .00 .16 658.85
391.10 .16 .302 .2974 .00 .16 730.54
391.20 .17 .332 .2997 .00 .17 802.80
391.30 .18 .362 .3021 .00 .18 875.61
391.40 .19 .392 .3045 .00 .19 949.02
391.50 .19 .423 .3069 .00 .19 1023.01
391.60 .20 .453 .3093 .00 .20 1097.58
391.70 .21 .485 .3117 .00 .21 1172.73
391.80 .21 .516 .3141 .00 .21 1248.44
391.90 .22 .547 .3166 .00 .22 1324.76
392.00 .23 .579 .3190 .00 .23 1401.68
392.10 1.46 .611 .3213 .00 1.46 1480.39
392.20 3.72 .643 .3235 .00 3.72 1560.67
LONG LAKE SUBDIVISION - TRACT 1
POND A - PONDPACK OUTPUT FOR WETLAND DESIGN
Type.... Pond E-V-Q Table Page 6.02
Name.... POND A
File.... K:\01\01-110\01113\H&H\SWMP\PPW WETLANDS\POND A TRACTI WETLAND.PPW
LEVEL POOL ROUTING DATA
HYG Dir = K:\01\01-110\01113\H&H\SWMP\PPW WETLANDS\
Inflow HYG file = NONE STORED - POND A IN 2-yr
Outflow HYG file = NONE STORED - POND A OUT 2-yr
Pond Node Data = POND A
Pond Volume Data = POND A
Pond Outlet Data = OUTLET
No Infiltration
INITIAL CONDITIONS
--------
Starting -------------
WS Elev = --------
390.00 ----
ft -
Starting Volume = .000 ac- ft
Starting Outflow = .00 cfs
Starting Infiltr. _ .00 cfs
Starting Total Qout= .00 cfs
Time Increment = .0100 hrs
Elevation Outflow Storage Area Infilt. Q Total 2S/t + O
ft cfs
- ac-ft
--------
---- acres
----- cfs
----------- cfs
--------
- cfs
-
--------
------------
392.30 ------------
6.64 .676 ---
.3258 .00 --
-
6.64 -
1642.15
392.40 10.10 .709 .3281 .00 10.10 1724.74
392.50 14.03 .741 .3304 .00 14.03 1808.34
392.60 18.36 .775 .3327 .00 18.36 1892.92
392.70 23.08 .808 .3350 .00 23.08 1978.44
392.80 28.09 .842 .3373 .00 28.09 2064.78
392.90 33.37 .875 .3397 .00 33.37 2151.98
393.00 35.35 .910 .3420 .00 35.35 2236.45
393.10 35.70 .944 .3467 .00 35.70 2320.13
393.20 36.05 .979 .3513 .00 36.05 2404.94
393.30 36.39 1.014 .3561 .00 36.39 2490.86
393.40 36.73 1.050 .3608 .00 36.73 2577.95
393.50 37.06 1.086 .3656 .00 37.06 2666.18
393.60 37.40 1.123 .3704 .00 37.40 2755.58
393.70 37.73 1.161 .3753 .00 37.73 2846.15
393.80 38.06 1.198 .3801 .00 38.06 2937.86
393.90 38.38 1.237 .3851 .00 38.38 3030.78
394.00 38.70 1.275 .3900 .00 38.70 3124.89
394.10 39.02 1.314 .3935 .00 39.02 3220.02
394.20 39.34 1.354 .3971 .00 39.34 3316.00
394.30 39.65 1.394 .4006 .00 39.65 3412.81
394.40 39.96 1.434 .4042 .00 39.96 3510.52
394.50 40.27 1.475 .4078 .00 40.27 3609.08
LONG LAKE SUBDIVISION - TRACT 1
POND A - PONDPACK OUTPUT FOR WETLAND DESIGN
Type.... Pond E-V-Q Table Page 6.03
Name.... POND A
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND A TRACTI_WETLAND.PPW
LEVEL POOL ROUTING DATA
HYG Dir = K:\01\01-110\01113\H&H\SWMP\PPW WETLANDS\
Inflow HYG file = NONE STORED - POND A IN 2-yr
Outflow HYG file = NONE STORED - POND A OUT 2-yr
Pond Node Data = POND A
Pond Volume Data = POND A
Pond Outlet Data = OUTLET
No Infiltration
INITIAL CONDITIONS
Starting WS Elev = 390.00 ft
Starting Volume = .000 ac- ft
Starting Outflow = .00 cfs
Starting Infiltr. _ .00 cfs
Starting Total Qout= .00 cfs
Time Increment = .0100 hrs
Elevation Outflow Storage Area Infilt. Q Total 2S/t + O
ft cfs ac-ft acres
- cfs
----------- cfs
------------ cfs
----------
------------
394.60 -------------
40.58 --------
1.516 ---- ---
----
.4114 .00 40.58 3708.52
394.70 40.88 1.557 .4150 .00 40.88 3808.83
394.80 41.19 1.599 .4187 .00 41.19 3909.99
394.90 41.48 1.641 .4223 .00 41.48 4012.05
395.00 41.78 1.683 .4260 .00 41.78 4115.01
LONG LAKE SUBDIVISION - TRACT 1
POND A - PONDPACK OUTPUT FOR WETLAND DESIGN
Type.... C and Area
Name.... AREA POND A
Page 7.01
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND A_TRACTI WETLAND.PPW
RATIONAL C COEFFICIENT DATA
.........................................................................
.........................................................................
Area C x Area
Soil/Surface Description C acres acres
-------------------------------- -------- ---------- ----------
Impervious Area .9500 6.050 5.748
Pervious Area .2500 6.170 1.543
WEIGHTED C & TOTAL AREA ---> .5966 12.220 7.290
.........................................................................
.........................................................................
LONG LAKE SUBDIVISION - TRACT 1
POND A - PONDPACK OUTPUT FOR WETLAND DESIGN
Type.... Rational Peak Q's
Name.... POST QPEAK
Page 7.02
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND A_TRACTI_WETLAND.PPW
SUMMARY OF RATIONAL METHOD PEAK DISCHARGES
Q = CiA * Units Conversion; Where Conversion = 43560 / (12 * 3600)
Rational Storms: RAL IDF.IDQ Raleigh IDF
Tag
----- Freq
------ File
------
------ IDF Curve
-----------
-----
100-yr 100 RAL_ID F.IDF 100-yr IDF Table
Tc = .0833 hrs

Tag
Freq
C
C adj ----------
C --------
I -----------
Area
Peak Q
(years) factor final in/hr acres cfs
-----
1-yr ------
1 -----
.597 ------
1.000 ----------
I .597 --------
4.6080 -----------?
12.220 ----------
33.87
10-yr 10 .597 1.000 .597 7.5000 12.220 55.13
100-yr 100 .597 1.000 .597
---------- 9.7200
-------- 12.220
----------- 71.45
LONG LAKE SUBDIVISION - TRACT 1
POND A - PONDPACK OUTPUT FOR WETLAND DESIGN
Type.... Mod. Rational Storm Calcs Page 7.03
Name.... AREA POND A Tag: 2-yr Event: 2 yr
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND A_TRACTI_WETLAND.PPW
Storm... 2-yr IDF Table Tag: 2-yr
MODIFIED RATIONAL METHOD
---- Summary for Single Storm Frequency ----
Q = CiA * Units Conversion; Where Conversion = 43560 / (12 * 3600)
RETURN
------- FREQUENCY:
---------- 2 yr 'C'
---------- Adjustment
----------- = 1.000Allowable
------------------- Q = 10.00
---------- cfs
---------
Hydrograph Storm Duration, Td = .7167 hrs Tc = .0833 hrs
Hydrograph File:
................. 2-yr
..........
...........
........
...........
.........
..........
....... .......... .......... ........... ........ ........... ...................
VOLUMES
Wtd. Adjusted Duration Intens. Area Qpeak Inflow Storage
'C' 'C' hrs in/hr acres cfs ac-ft
- ac-ft
---------
-------
.597 ----------
.597 ----------
.0833 -----------
5.7600 --------
12.220 -------- --
42.34 I --
------
.292 -
.223
.597 .597 .1667 4.7640 12.220 35.02 .482 .379
.597 .597 .2500 4.0400 12.220 29.70 .614 .476
.597 .597 .3333 3.4685 12.220 25.50 .702 .530
.597 .597 .5000 2.7000 12.220 19.85 .820 .579
.597 .597 .6667 2.2808 12.220 16.77 .924 .614
************************************************************ Storage Maximum
.597 .597 .7167 2.1783 12.220 16.01 I .948 .618
****************************************************************************
.597 .597 .8333 1.9395 12.220 14.26 .982 .603
.597 .597 1.0000 1.7000 12.220 12.50 I 1.033 .585
.597 .597 2.0000 .9500 12.220 6.98 Qpeak < Qallow
LONG LAKE SUBDIVISION - TRACT 1
POND A - PONDPACK OUTPUT FOR WETLAND DESIGN
Type.... Mod. Rational Storm Calcs Page 7.04
Name.... AREA POND A Tag: 10-yr Event: 10 yr
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND A_TRACTI_WETLAND.PPW
Storm... 10-yr IDF Table Tag: 10-yr
MODIFIED RATIONAL METHOD
---- Summary for Single Storm Frequency ----
Q = CiA * Units Conversion; Where Conversion = 43560 / (12 * 3600)
RETURN
------- FREQUENCY:
---------- 10 yr 'C' Adjustment = 1.000Allowable
---------------------------------------- Q = 13.00
----------- cfs
--------
Hydrograph Storm Duration, Td = .9167 hrs Tc = .0833 hrs
Hydrograph File:
................. 10-yr
.........
...........
........
............
..........
.........
...... ........... ......... ........... ........ ............ ...................
VOLUMES
Wtd. Adjusted Duration Intens. Area Qpeak Inflow Storage
'C' 'C' hrs in/hr acres cfs ac-ft
---------- ac-ft
---
-----
------
.597 -----------
.597 ---------
.0833 -----------
7.5000 --------
12.220 --------- --
55.13 .380 -
.290
.597 .597 .1667 6.1355 12.220 45.10 I .621 .487
.597 .597 .2500 5.2500 12.220 38.59 .797 .618
.597 .597 .3333 4.6218 12.220 33.98 I .936 .712
.597 .597 .5000 3.7100 12.220 27.27 1.127 .814
.597 .597 .6667 3.1511 12.220 23.16 1.276 .873
.597 .597 .8333 2.7094 12.220 19.92 I 1.372 .879
************************************************************ Storage Maximum
.597 .597 .9167 2.5597 12.220 18.82 1.426 .888
****************************************************************************
.597 .597 1.0000 2.4100 12.220 17.72 1.464 .882
.597 .597 2.0000 1.3700 12.220 10.07 Qpeak < Qallow
LONG LAKE SUBDIVISION - TRACT 1
POND A - PONDPACK OUTPUT FOR WETLAND DESIGN
Type.... Mod. Rational Storm Calcs Page 7.05
Name.... AREA POND A Tag: 100-yr Event: 100 yr
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND A_TRACTI_WETLAND.PPW
Storm... 100-yr IDF Table Tag: 100-yr
MODIFIED RATIONAL METHOD
---- Summary for Single Storm Frequency ----
Q = CiA * Units Conversion; Where Conversion = 43560 / (12 * 3600)
RETURN
------- FREQUENCY:
---------- 100 yr
--------- 'C' Adjustment =
------------------ 1.000Allowable
-------------- Q = 14.00
----------- cfs
-------
Hydrograph Storm Duration, Td = 1.1500 hrs Tc = .0833 hrs
Hydrograph File:
................. 100-yr
.........
............
......
..............
...........
.......
....... .......... ......... ............ ...... .............. ..................
VOLUMES
Wtd. Adjusted Duration Intens. Area Qpeak Inflow Storage
-C' 'C' hrs in/hr acres cfs ac-ft ac-ft
-------
------
.597 -----------
.597 ---------
.0833 ------------
9.7200 ------
12.220 ---------- ---
71.45 ----------
.492 -
.395
.597 .597 .1667 8.4053 12.220 61.79 I .851 .706
.597 .597 .2500 7.2400 12.220 53.22 I 1.100 .907
.597 .597 .3333 6.4676 12.220 47.54 1.310 1.069
.597 .597 .5000 5.2800 12.220 38.81 1.604 1.266
.597 .597 .6667 4.4816 12.220 32.95 1.815 1.381
.597 .597 .8333 3.8792 12.220 28.52 1.964 1.434
.597 .597 1.0000 3.5000 12.220 25.73 2.126 1.500
************************************************************ Storage Maximum
.597 .597 1.1500 3.2090 12.220 23.59 I 2.242 1.529
****************************************************************************
.597 .597 2.0000 2.0000 12.220 14.70 2.430 1.225
.597 .597 3.0000 1.5000 12.220 11.03 Qpeak < Qallow
LONG LAKE SUBDIVISION - TRACT 1
POND A - PONDPACK OUTPUT FOR WETLAND DESIGN
Elev. vs. Flow
STAGE-DISCHARGE FUNCTION FOR OUTLET
w
Hydrograph for 1-year Design Storm
WETLAND IN vs OUT
N
U
3
0
LL
Plotted Curves
OUTLET
Plotted Curves
WETLAND IN 1-yr
WETLANDOUT 1-yr
0 10 20 30 40
Flow (cfs)
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Time (hrs)
LONG LAKE SUBDIVISION - TRACT 1
POND A - PONDPACK OUTPUT FOR WETLAND DESIGN
Hydrograph for 10-yr Design Storm
WETLAND IN w OUT
0
Hydrograph for 100-yr Design Storm
WETLAND IN vs OUT
N
U
O
LL
Plotted Curves
WETLAND IN 10-yr
WETLAND OUT. 10-yr
Plotted Curves
p WETLAND IN 100-yr
WETLAND OUT 100-yr
4
2.5 3.0 3.5 4.0
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Time (hrs)
0.0 0.5 1.0 1.5 2.0
Time (hrs)
LONG LAKE SUBDIVISION - TRACT 1
POND A - PONDPACK OUTPUT FOR WETLAND DESIGN
Volume z Time
MINIMUM DRAIN TIME -Runoff from first 1" Rainfall
0 10 20 30 40 50 60 70 60
Time (hrs)
1
0
•
POND C
Long Lake Subdivision
Tract s, Phases 3 & 4
Project Name: Long Lake Subdivision - Tract 1
City/State: Raleigh, NC
Project #: 201113.2
Date: 13-Aug-02
Table 1.1 Surface Area to Drainage Area Ratio for Permanent Pool Sizing for 85% Pollutant
Removal Efficiencv in the Piedmont
% Impervious
Cover Permanent Pool Depth (feet)
3.0 4.0 5.0 6.0 7.0 8.0 9.0
10 0.59 0.49 0.43 0.35 0.31 0.29 0.26
20 0.97 0.79 0.70 0.59 0.51 0.46 0.44
30 1.34 1.08 0.97 0.83 0.70 0.64 0.62
40 1.73 1.43 1.25 1.05 0.90 0.82 0.77
50 2.06 1.73 1.50 1.30 1.09 1.00 0.92
60 2.40 2.03 1.71 1.51 1.29 1.18 1.10
70 2.88 2.40 2.07 1.79 1.54 1.35 1.26
80 3.36 2.78 2.38 2.10 1.86 1.60 1.42
90 3.74 3.10 2.66 2.34 2.11 1.83 1.67
Source: NCDENR/DWQ Stormwater Best Management Practices, pg. 5, April 1999
POND C - TRACT 1, PHASES 3 & 4 (Constructed Wetland)
Pervious
(ac) Impervious
(ac) Total
Area (ac)
FES #45A 4.79 2.73 7.52
% Impervious Surface Area =
Surface Area of Permanent Pool:
36 %
Assumed depth = 3 feet
SA/DA ratio = 1.57 % From Table 1.1
Minimum pond surface area (SA) _ (DA * SA/DA ratio)/100
SA = 0.118 acres
5156 sq. ft.
Normal pool elevation = 396 feet
Surface area provided = 0.123 acres
5342 sq. ft.
1-Inch Runoff Volume Calculation
Using the runoff volume calculations in the "Simple Method" as described by Schueler (1987)
Rv = 0.05 + 0.009(1) where, Rv = Runoff coefficient, in./in.
I = Percent impervious
Rv = 0.38 in./in.
Total runoff volume from 1-inch precipitation:
Runoff volume, S = (Design rainfall) (Rv) (Drainage Area)
S = 0.236 acre-ft
10284 cu. ft.
Riser structure crest elevation = 398 feet
Runoff storage provided = 0.281 ac-ft
"12232 cu. ft.
LONG LAKE SUBDIVISION - TRACT 1, PHASES 3 & 4
POND C - PONDPACK OUTPUT
Job File: K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND C_TRACT 1 PH 3-4_WETLAND.PPW
Rain Dir: I:\ENGFILE\HAESTAD\PPW RAINFALL DATA\WAKE CO\
--------------------------
--------------------------
JOB TITLE
--------------------------
--------------------------
LONG LAKE SUBDIVISION - TRACT 1
Pond C - Tract 1, Phases 3 & 4
Constructed Wetland Design
Raleigh, North Carolina
W&R Project #201113.2
The Modified Rational Method was used to determine peak discharge rates for the 2-year,
10-year and 100-year design storm events for the Raleigh/Durham, North Carolina area and
size the detention storage for the dry detention pond due to the small drainage area
(±7.5 acres). The Modified Rational Method is an extension of the rational method for
rainfalls with durations greater than the time of concentration. The method was modified
so that the concepts of the rational method (peak discharge) could be used to develop
hydrographs for storage routing. The Modified Rational Method within PondPack calculates
the storage volume for hydrographs of rainfalls of various durations to determine the
critical duration for the design storm as the one requiring the greatest detention
storage volume. This critical duration is used to calculate the discharge rate and
volume of water that is routed through the pond structure. The hydrograph developed
maintains the calculated volume and adjusts the peak discharge rate accordingly. Thus,
the peak discharge for the Modified Rational method is less than the calculated Rational
Method.
The rainfall data used in this design was taken from the Intensity-Duration-Frequency
Table for the Raleigh area published in the City of Raleigh Stormwater Management Design
Manual. The post-development time of concentration was set at 5 minutes to account for
the piped drainage system.
Pond C is an extended detention wetland that is designed to capture the volume of runoff
from the first 1-inch of rainfall and slowly release it over a 48 to 72 hour period. In
addition, the wetland is designed to pass the 100-year design storm through the
riser/barrel outlet structure of the pond.
Pond C Design Summary:
Normal Pool Elevation =
Required Surface Area =
Surface Area Provided =
396'
0.118 acres (5156 sq ft)
0.123 acres (5342 sq ft)
Required Storage Volume = 0.236 ac-ft (10,280 cu ft)
Storage Volume Provided = 0.281 ac-ft (12,232 cu ft)
Top of Dam = 400.5'
Calculated Freeboard for the 10-yr design storm = 1.9 ft
Calculated Freeboard for the 100-yr design storm = 1.2 ft
Outlet Structure:
¦ 48" RCP Riser structure with crest at 398'
¦ 15" RCP Barrel; 94 ft length; Inverts at 394.5' and 394'
¦ Floating Skimmer device with constant Q = 0.06 cfs for draw-down
LONG LAKE SUBDIVISION - TRACT 1, PHASES 3 & 4
POND C - PONDPACK OUTPUT
Table of Contents
******************r*** MASTER SUMMARY **********************
Watershed....... Mod. Rational Grand Summary ........ 1.01
Master Network Summary ............. 1.02
********************** RAINFALL DATA ***********************
2-yr IDF Table.. 2-yr
I-D-F Table ........................ 2.01
10-yr IDF Table 10-yr
I-D-F Table ........................ 2.01
100-yr IDF Table 100-yr
I-D-F Table ........................ 2.02
***************r****** TC CALCULATIONS *********************
AREA POND C..... Tc Calcs ........................... 3.01
******r**************** POND VOLUMES ***********************
WETLAND......... Vol: Elev-Area ..................... 4.01
******************** OUTLET STRUCTURES *********************
OUTLET POND C... Outlet Input Data .................. 5.01
Composite Rating Curve ............. 5.04
*********************** POND ROUTING ***********************
WETLAND......... Pond E-V-Q Table ....... .......... 6.01
****************** RATIONAL METHOD CALCS ************* ******
AREA POND C..... C and Area ......................... 7.01
AREA POND C..... Rational Peak Qs .................... 7.02
AREA POND C..... 2-yr Mod. Rational Storm Calcs ..... 7.03
AREA POND C..... 10-yr Mod. Rational Storm Calcs .... 7.04
AREA POND C..... 100-yr Mod. Rational Storm Calcs ... 7.05
LONG LAKE SUBDIVISION - TRACT 1, PHASES 3 & 4
POND C - PONDPACK OUTPUT
Type.... Mod. Rational Grand Summary Page 1.01
Name.... Watershed
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND C_TRACT 1 PH 3-4_WETLAND.PPW
************************************************************************
************************************************************************
*
*
* MODIFIED RATIONAL METHOD
* ---- Grand Summary For All Storm Frequencies ----
*
*
************************************************************************
************************************************************************
Q = CiA * Units Conversion; Where Conversion = 43560 / (12 * 3600)
Area =
. 7.520 acres
..........
....... Tc
............... = .0833
........ hrs
..........
................
................ ........
......... .
........... ....... ............... ..................
VOLUMES
Freq. Adjusted Duration I Qpeak Allowable Inflow Storage
years 'c'
---------------- hrs
--------- in/hr
----------- cfs
------- cfs I
----------- -- ac-ft
--------- ac-ft
----------
2 .503 .6000 2.4485 9.34 7.00 I .463 .266
10 .503 .5833 3.4306 13.09 11.00 I .631 .328
100 .503 .7333 4.2402 16.18 12.00 .981 .576
LONG LAKE SUBDIVISION - TRACT 1, PHASES 3 & 4
POND C - PONDPACK OUTPUT
Type.... Master Network Summary Page 1.02
Name.... Watershed
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND C_TRACT 1 PH 3-4_WETLAND.PPW
MASTER DESIGN STORM SUMMARY
Default Network Design Storm File, ID RAL_IDF.IDQ Raleigh IDF
Rainfall
Return Event Type IDF File IDF ID
------------ --------------- -------- ----------------
2-yr I-D-F Table RAL_IDF 2-yr IDF Table
10-yr I-D-F Table RAL IDF 10-yr IDF Table
100-yr I-D-F Table RAL_IDF 100-yr IDF Table
MASTER NETWORK SUMMARY
Modified Rational Method Network
(*Node=Outfall; +Node=Diversion;)
(Trun= HYG Truncation: Blank=None; L=Left; R=Rt; LR=Left&Rt)
Return HYG Vol
Node ID Type Event ac-ft Trun
---
-------------
AREA POND C ---- ----
AREA ------
2 -------
.463
AREA POND C AREA 10 .631
AREA POND C AREA 100 .981
*OUTFALL JCT 2 .275
*OUTFALL JCT 10 .443
*OUTFALL JCT 100 .791
WETLAND IN POND 2 .463
WETLAND IN POND 10 .631
WETLAND IN POND 100 .980
WETLAND OUT POND 2 .275
WETLAND OUT POND 10 .443
WETLAND OUT POND 100 .791
Max
Qpeak Qpeak Max WSEL Pond Storage
hrs cfs ft ac-ft
------
---------
.0833 --------
9.34 -------- ------
.0833 13.09
.0833 16.18
.6000 8.75
.5900 11.21
.7500 12.34
.0900 9.34
.0900 13.09
.0900 16.18
.6000 8.75 398.37 .340
.5900 11.21 398.60 .380
.7500 12.34 399.30 .503
LONG LAKE SUBDIVISION - TRACT 1, PHASES 3 & 4
POND C - PONDPACK OUTPUT
Type.... I-D-F Table Page 2.01
Name.... 2-yr IDF Table Tag: 2-yr Event: 2 yr
File.... I:\ENGFILE\HAESTAD\PPW RAINFALL DATA\WAKE CO\RAL_IDF.IDF
Title... 2-yr Storm from City of Raleigh IDF Table
Storm... 2-yr IDF Table Tag: 2-yr
Rainfall-Intensity-Duration Curve
Time, hrs Intens., in/hr
.0833
.1670
.2500
.3330
.5000
.6670
.8330
1.0000
1.5000
2.0000
3.0000
6.0000
12.0000
24.0000
5.7600
4.7600
4.0400
3.4700
2.7000
2.2800
1.9400
1.7000
1.2200
.9500
.7100
.4400
.2600
.1500
Type.... I-D-F Table
Name.... 10-yr IDF Table Tag: 10-yr Event: 10 yr
File.... I:\ENGFILE\HAESTAD\PPW RAINFALL DATA\WAKE CO\RAL_IDF.IDF
Title... 10-yr Event Table from City of Raleigh IDF Table
Storm... 10-yr IDF Table Tag: 10-yr
Rainfall-Intensity-Duration Curve
Time, hrs Intens., in/hr
.0833 7.5000
.1670 6.1300
.2500 5.2500
.3300 4.6400
.5000 3.7100
.6670 3.1500
.8330 2.7100
1.0000 2.4100
1.5000 1.7400
2.0000 1.3700
3.0000 1.0200
6.0000 .6500
12.0000 .3900
24.0000 .2200
LONG LAKE SUBDIVISION - TRACT 1, PHASES 3 & 4
POND C - PONDPACK OUTPUT
Type.... I-D-F Table Page 2.02
Name.... 100-yr IDF Table Tag: 100-yr Event: 100 yr
File.... I:\ENGFILE\HAESTAD\PPW RAINFALL DATA\WAKE CO\RAL_IDF.IDF
Title... 100-yr Event from City of Raleigh IDF Table
Storm... 100-yr IDF Table Tag: 100-yr
Rainfall-Intensity-Duration Curve
Time, hrs Intens., in/hr
.0833
.1670
.2500
.3330
.5000
.6670
.8330
1.0000
1.5000
2.0000
3.0000
6.0000
12.0000
24.0000
9.7200
8.4000
7.2400
6.4700
5.2800
4.4800
3.8800
3.5000
2.5300
2.0000
1.5000
.9600
.5700
.3300
LONG LAKE SUBDIVISION - TRACT 1, PHASES 3 & 4
POND C - PONDPACK OUTPUT
Type.... Tc Calcs
Name.... AREA POND C
Page 3.01
File.... K:\01\01-110\01113\H&H\SWMP\PPW WETLANDS\POND C -TRACT 1 PH 3-4 WETLAND.PPW
........................................................................
........................................................................
TIME OF CONCENTRATION CALCULATOR
........................................................................
........................................................................
Segment #1: Tc: User Defined
Description: Time of Concentration = 5 minutes
Segment #1 Time: .0833 hrs
------------------------------------------------------------------------
-------------------------
-------------------------
Total Tc: .0833 hrs
Calculated Tc < Min.Tc:
Use Minimum Tc...
Use Tc = .0833 hrs
-------------------------
-------------------------
LONG LAKE SUBDIVISION TRACT 1, PHASES 3 & 4
POND C PONDPACK OUTPUT
Type.... Vol: Elev-Area
Name.... WETLAND
Page 4.01
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND C_TRACT 1 PH 3-4_WETLAND.PPW
Elevation Planimeter Area Al+A2+sgr(AI*A2) Volume Volume Sum
(ft)
--------- (sq.in) (acres)
---------------------- (acres)
----------------- (ac-ft)
--------- (ac-ft)
-------------
--
396.00 ----- .1230 .0000 .000 .000
397.00 ----- .1400 .3942 .131 .131
398.00 ----- .1590 .4482 .149 .281
399.00 ----- .1780 .5052 .168 .449
400.00 ----- .1970 .5623 .187 .637
POND VOLUME EQUATIONS
* Incremental volume computed by the Conic Method for Reservoir Volumes.
Volume = (1/3) * (EL2-ELI) * (Areal + Area2 + sq.rt.(Area1*Area2))
where: EL1, EL2 = Lower and upper elevations of the increment
Areal,Area2 = Areas computed for EL1, EL2, respectively
Volume = Incremental volume between EL1 and EL2
LONG LAKE SUBDIVISION - TRACT 1, PHASES 3 & 4
POND C - PONDPACK OUTPUT
Type.... Outlet Input Data
Name.... OUTLET POND C
Page 5.01
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND C_TRACT 1 PH 3-4_WETLAND.PPW
REQUESTED POND WS ELEVATIONS:
Min. Elev.= 396.00 ft
Increment = .10 ft
Max. Elev.= 400.00 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
User Defined Table SK ---> TW .000 400.000
Stand Pipe RI ---> CV 398.000 400.000
Culvert-Circular CV ---> TW 394.500 400.000
TW SETUP, DS Channel
LONG LAKE SUBDIVISION - TRACT 1, PHASES 3 & 4
POND C - PONDPACK OUTPUT
Type.... Outlet Input Data
Name.... OUTLET POND C
Page 5.02
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND C_TRACT 1 PH 3-4_WETLAND.PPW
OUTLET STRUCTURE INPUT DATA
Structure ID = SK
Structure Type = User Defined Table
------------------------------------
ELEV-FLOW RATING TABLE
Elev, ft Flow, cfs
--------- ---------
396.00 .06
400.00 .06
Structure ID = RI
Structure Type = Stand Pipe
-----------------
# of openings -------------
= 1 ------
Invert Elev. = 398.00 ft
Diameter = 4.0000 ft
Orifice Area = 12.5664 sq.ft
Orifice Coeff. _ .600
Weir Length = 12.57 ft
Weir Coeff. = 3.100
K, Submerged = .000
K, Reverse = 1.000
Kb,Barrel = .000000 (per ft of full flow)
Barrel Length = .00 ft
Mannings n = .0000
LONG LAKE SUBDIVISION - TRACT 1, PHASES 3 & 4
POND C - PONDPACK OUTPUT
Type.... Outlet Input Data
Name.... OUTLET POND C
Page 5.03
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND C_TRACT 1 PH 3-4 WETLAND.PPW
OUTLET STRUCTURE INPUT DATA
Structure ID = CV
Structure Type = Culvert-Circular
-------------
------------------
No. Barrels -----
= 1
Barrel Diameter = 1.2500 ft
Upstream Invert = 394.50 ft
Dnstream Invert = 390.50 ft
Horiz. Length = 94.00 ft
Barrel Length = 94.09 ft
Barrel Slope = .04255 ft/ft
OUTLET CONTROL DATA...
Mannings n = .0130
Ke = .5000
Kb = .023225
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) = 1.139
T2 ratio (HW/D) = 1.286
Slope Factor = -.500
Use unsubmerged inlet control Form 1 equ. below TI 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 = 395.92 ft ---> Flow = 4.80 cfs
At T2 Elev = 396.11 ft ---> Flow = 5.49 cfs
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
LONG LAKE SUBDIVISION - TRACT 1, PHASES 3 & 4
POND C - PONDPACK OUTPUT
Type.... Composite Rating Curve
Name.... OUTLET POND C
Page 5.04
File.... K:\01\01-110\01113\H&H\SWMP\PPW WETLANDS\POND C -TRACT 1 PH 3-4 WETLAND.PPW
***** COMPOSITE OUTFLOW SUMMARY ****
WS Elev, Total Q Notes
-------- -------- ------ -- Converge ----------- --------------
Elev. Q TW Elev Error
ft cfs ft +/-ft Contributing Structures
--------
396.00 -------
.06 ------
Free -- -----
Outfall -----------
SK (no Q: ---------------
RI,CV)
396.10 .06 Free Outfall SK (no Q: RI,CV)
396.20 .06 Free Outfall SK (no Q: RI,CV)
396.30 .06 Free Outfall SK (no Q: RI,CV)
396.40 .06 Free Outfall SK (no Q: RI,CV)
396.50 .06 Free Outfall SK (no Q: RI,CV)
396.60 .06 Free Outfall SK (no Q: RI,CV)
396.70 .06 Free Outfall SK (no Q: RI,CV)
396.80 .06 Free Outfall SK (no Q: RI,CV)
396.90 .06 Free Outfall SK (no Q: RI,CV)
397.00 .06 Free Outfall SK (no Q: RI,CV)
397.10 .06 Free Outfall SK (no Q: RI,CV)
397.20 .06 Free Outfall SK (no Q: RI,CV)
397.30 .06 Free Outfall SK (no Q: RI,CV)
397.40 .06 Free Outfall SK (no Q: RI,CV)
397.50 .06 Free Outfall SK (no Q: RI,CV)
397.60 .06 Free Outfall SK (no Q: RI,CV)
397.70 .06 Free Outfall SK (no Q: RI,CV)
397.80 .06 Free Outfall SK (no Q: RI,CV)
397.90 .06 Free Outfall SK (no Q: RI,CV)
398.00 .06 Free Outfall SK (no Q: RI,CV)
398.10 1.29 Free Outfall SK,RI,CV
398.20 3.54 Free Outfall SK,RI,CV
398.30 6.46 Free Outfall SK,RI,CV
398.40 9.91 Free Outfall SK,RI,CV
398.50 11.05 Free Outfall SK,RI,CV
398.60 11.22 Free Outfall SK,RI,CV
398.70 11.38 Free Outfall SK,RI,CV
398.80 11.55 Free Outfall SK,RI,CV
398.90 11.71 Free Outfall SK,RI,CV
399.00 11.87 Free Outfall SK,RI,CV
399.10 12.03 Free Outfall SK,RI,CV
399.20 12.19 Free Outfall SK,RI,CV
399.30 12.34 Free Outfall SK,RI,CV
399.40 12.50 Free Outfall SK,RI,CV
399.50 12.65 Free Outfall SK,RI,CV
399.60 12.80 Free Outfall SK,RI,CV
399.70 12.95 Free Outfall SK,RI,CV
399.80 13.09 Free Outfall SK,RI,CV
399.90 13.24 Free Outfall SK,RI,CV
400.00 13.38 Free Outfall SK,RI,CV
LONG LAKE SUBDIVISION - TRACT 1, PHASES 3 & 4
POND C PONDPACK OUTPUT
Type.... Pond E-V-Q Table Page 6.01
Name.... WETLAND
File.... K:\01\01-110\01113\H&H\SWMP\PPW WETLANDS\POND C -TRACT 1 PH 3-4 WETLAND.PPW
LEVEL POOL ROUTING DATA
HYG Dir = K:\01\01-110\01113\H&H\SWMP\PPW WETLANDS\
Inflow HYG file = NONE STORED - WETLAND IN 2-yr
Outflow HYG file = NONE STORED - WETLAND OUT 2-yr
Pond Node Data = WETLAND
Pond Volume Data = WETLAND
Pond Outlet Data = OUTLET POND C
No Infiltration
INITIAL CONDITIONS
Starting WS Elev = 396.00 ft
Starting Volume = .000 ac- ft
Starting Outflow = .06 cfs
Starting Infiltr. _ .00 cfs
Starting Total Qout= .06 cfs
Time Increment = .0100 hrs
Elevation Outflow Storage Area Infilt. Q Total 2S/t + O
ft cfs ac-ft acres
- cfs cfs cfs
------------
396.00 ------------
.06 ---------
.000 ---- -------
.1230 -----------
.00 ------------
.06 ----------
.06
396.10 .06 .012 .1247 .00 .06 30.03
396.20 .06 .025 .1263 .00 .06 60.40
396.30 .06 .038 .1280 .00 .06 91.16
396.40 .06 .051 .1297 .00 .06 122.34
396.50 .06 .064 .1314 .00 .06 153.92
396.60 .06 .077 .1331 .00 .06 185.92
396.70 .06 .090 .1348 .00 .06 218.33
396.80 .06 .104 .1365 .00 .06 251.15
396.90 .06 .117 .1383 .00 .06 284.40
397.00 .06 .131 .1400 .00 .06 318.07
397.10 .06 .146 .1418 .00 .06 352.17
397.20 .06 .160 .1437 .00 .06 386.73
397.30 .06 .174 .1456 .00 .06 421.72
397.40 .06 .189 .1475 .00 .06 457.18
397.50 .06 .204 .1493 .00 .06 493.09
397.60 .06 .219 .1513 .00 .06 529.47
397.70 .06 .234 .1532 .00 .06 566.31
397.80 .06 .249 .1551 .00 .06 603.60
397.90 .06 .265 .1570 .00 .06 641.37
398.00 .06 .281 .1590 .00 .06 679.61
398.10 1.29 .297 .1609 .00 1.29 719.55
398.20 3.54 .313 .1627 .00 3.54 760.96
LONG LAKE SUBDIVISION - TRACT 1, PHASES 3 & 4
POND C - PONDPACK OUTPUT
Type.... Pond E-V-Q Table Page 6.02
Name.... WETLAND
File.... K:\01\01-110\01113\H&H\SWMP\PPW WETLANDS\POND C -TRACT 1 PH 3-4 WETLAND.PPW
LEVEL POOL ROUTING DATA
HYG Dir = K:\01\01-110\01113\H&H\SWMP\PPW WETLANDS\
Inflow HYG file = NONE STORED - WETLAND IN 2-yr
Outflow HYG file = NONE STORED - WETLAND OUT 2-yr
Pond Node Data = WETLAND
Pond Volume Data = WETLAND
Pond Outlet Data = OUTLET POND C
No Infiltration
INITIAL CONDITIONS
Starting WS Elev = 396.00 ft
Starting Volume = .000 ac- ft
Starting Outflow = .06 cfs
Starting Infiltr. _ .00 cfs
Starting Total Qout= .06 cfs
Time Increment = .0100 hrs
Elevation Outflow Storage Area Infilt. Q Total 2S/t + O
ft cfs ac-ft acres cfs cfs
-- cfs
-
------------
398.30 ------------
6.46 ---------
.329 ---- --------
.1646 -----------
.00 -------
---
6.46 -----
----
803.47
398.40 9.91 .346 .1665 .00 9.91 846.98
398.50 11.05 .363 .1684 .00 11.05 888.63
398.60 11.22 .380 .1703 .00 11.22 929.78
398.70 11.38 .397 .1722 .00 11.38 971.39
398.80 11.55 .414 .1741 .00 11.55 1013.44
398.90 11.71 .432 .1761 .00 11.71 1055.98
399.00 11.87 .449 .1780 .00 11.87 1098.98
399.10 12.03 .467 .1799 .00 12.03 1142.45
399.20 12.19 .485 .1817 .00 12.19 1186.36
399.30 12.34 .503 .1836 .00 12.34 1230.70
399.40 12.50 .522 .1855 .00 12.50 1275.52
399.50 12.65 .541 .1874 .00 12.65 1320.79
399.60 12.80 .559 .1893 .00 12.$0 1366.52
399.70 12.95 .578 .1912 .00 12.95 1412.71
399.80 13.09 .598 .1931 .00 13.09 1459.34
399.90 13.24 .617 .1951 .00 13.24 1506.46
400.00 13.38 .637 .1970 .00 13.38 1554.05
LONG LAKE SUBDIVISION - TRACT 1, PHASES 3 & 4
POND C - PONDPACK OUTPUT
Type.... C and Area
Name.... AREA POND C
Page 7.01
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND C_TRACT 1 PH 3-4_WETLAND.PPW
RATIONAL C COEFFICIENT DATA
.........................................................................
.........................................................................
Area C x Area
Soil/Surface Description C acres acres
-------------------------------- -------- ---------- ----------
Impervious Area 1.0000 2.730 2.730
Pervious Area .2200 4.790 1.054
WEIGHTED C & TOTAL AREA ---> .5032 7.520 3.784
.........................................................................
.........................................................................
LONG LAKE SUBDIVISION - TRACT 1, PHASES 3 & 4
POND C - PONDPACK OUTPUT
Type.... Rational Peak Q's
Name.... POST DEV
Page 7.02
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND C_TRACT 1 PH 3-4 WETLAND.PPW
SUMMARY OF RATIONAL METHOD PEAK DISCHARGES
Q = CiA * Units Conversion; Where Conversion = 43560 / (12 * 3600)
Rational Storms: RAL IDF.IDQ Raleigh IDF
Tag
----- Freq
------ File
------
------ IDF Curve
-----------
-----
100-yr 100 RAL_ID F.IDF 100-yr IDF Table
Tc = .0833 hrs

Tag
Freq
C
C adj ----------
C --------
I -----------
Area I
Peak Q
(years) factor final in/hr acres cfs
-----
2-yr ------
2 -----
.503 ------
1.000 I----------
.503 --------
5.7600 -----------?
7.520 ----------
21.98
10-yr 10 .503 1.000 .503 7.5000 7.520 28.62
100-yr 100 .503 1.000 .503
---------- 9.7200
-------- 7.520
----------- 37.09
LONG LAKE SUBDIVISION - TRACT 1, PHASES 3 & 4
POND C - PONDPACK OUTPUT
Type.... Mod. Rational Storm Calcs Page 7.03
Name.... AREA POND C Tag: 2-yr Event: 2 yr
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND C_TRACT 1 PH 3-4_WETLAND.PPW
Storm... 2-yr IDF Table Tag: 2-yr
MODIFIED RATIONAL METHOD
---- Summary for Single Storm Frequency ----
Q = CiA * Units Conversion; Where Conversion = 43560 / (12 * 3600)
RETURN
------- FREQUENCY:
---------- 2 yr 'C'
---------- Adjustment
----------- = 1.000Allowable
------------------- Q = 7.00
--------- cfs
----------
Hydrograph Storm Duration, Td = .6000 hrs Tc = .0833 hrs
Hydrograph File:
................. 2-yr
..........
...........
.......
............
........
...........
....... .......... .......... ........... ....... ............ ...................
VOLUMES
Wtd. Adjusted Duration Intens. Area Qpeak I Inflow Storage
'C' hrs in/hr acres cfs ac-ft ac-ft
-
---
-------
.503 ----------
.503 ----------
.0833 -----------
5.7600 -------
7.520 --------- --
21.98 I --------
.151 -----
--
.103
.503 .503 .1667 4.7640 7.520 18.18 .250 .178
.503 .503 .2500 4.0400 7.520 15.42 I .318 .222
.503 .503 .3333 3.4685 7.520 13.23 .365 .244
.503 .503 .5000 2.7000 7.520 10.30 .426 .257
************************************************************ Storage Maximum
.503 .503 .6000 2.4485 7.520 9.34 .463 .266
****************************************************************************
503 .503 .6667 2.2808 7.520 8.70 .479 .263
503 .503 .8333 1.9395 7.520 7.40 I .510 .245
503 .503 1.0000 1.7000 7.520 6.49 Qpeak < Qallow
LONG LAKE SUBDIVISION - TRACT 1, PHASES 3 & 4
POND C - PONDPACK OUTPUT
Type.... Mod. Rational Storm Calcs Page 7.04
Name.... AREA POND C Tag: 10-yr Event: 10 yr
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND C_TRACT 1 PH 3-4_WETLAND.PPW
Storm... 10-yr IDF Table Tag: 10-yr
MODIFIED RATIONAL METHOD
---- Summary for Single Storm Frequency ----
Q = CiA * Units Conversion; Where Conversion = 43560 / (12 * 3600)
RETURN
------ FREQUENCY:
----------- 10 yr 'C' Adjustment = 1.000Allowable
---------------------------------------- Q = 11.00
----------- cfs
--------
Hydrograph Storm Duration, Td = .5833 hrs Tc = .0833 hrs
Hydrograph File:
................. 10-yr
.........
...........
........
............
..........
.........
...... ........... ......... ........... ........ ............ ...................
VOLUMES
Wtd. Adjusted Duration Intens. Area Qpeak Inflow Storage
-C' 'C' hrs in/hr acres cfs
- ac-ft
---
- ac-ft
---------
------
.503 -----------
.503 ---------
.0833 -----------
7.5000 --------
7.520 --------- -
28.62 ---
---
.197 .121
.503 .503 .1667 6.1355 7.520 23.41 I .322 .209
.503 .503 .2500 5.2500 7.520 20.03 .414 .262
.503 .503 .3333 4.6218 7.520 17.63 .486 .296
.503 .503 .5000 3.7100 7.520 14.16 .585 .320
************************************************************ Storage Maximum
.503 .503 .5833 3.4306 7.520 13.09 I .631 .328
.503 .503 .6667 3.1511 7.520 12.02 .662 .322
.503 .503 .8333 2.7094 7.520 10.34 Qpeak < Qallow
LONG LAKE SUBDIVISION - TRACT 1, PHASES 3 & 4
POND C - PONDPACK OUTPUT
Type.... Mod. Rational Storm Calcs Page 7.05
Name.... AREA POND C Tag: 100-yr Event: 100 yr
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND C_TRACT 1 PH 3-4_WETLAND.PPW
Storm... 100-yr IDF Table Tag: 100-yr
MODIFIED RATIONAL METHOD
---- Summary for Single Storm Frequency ----
Q = CiA * Units Conversion; Where Conversion = 43560 / (12 * 3600)
RETURN
------ FREQUENCY:
----------- 100 yr
--------- 'C' Adjustment =
------------------ 1.000Allowable
-------------- Q = 12.00
---------- cfs
--------
Hydrograph Storm Duration, Td = .7333 hrs Tc = .0833 hrs
Hydrograph File:
................. 100-yr
.........
...........
.......
..............
..........
........
...... ........... ......... ........... ....... .............. ..................
VOLUMES
Wtd. Adjusted Duration Intens. Area Qpeak Inflow Storage
'C' 'C' hrs in/hr acres cfs ac-ft
- ac-ft
--
------
.503 -----------
.503 ---------
.0833 -----------
9.7200 -------
7.520 ---------- ---
37.09 I ------
---
.255 ----
--
.172
.503 .503 .1667 8.4053 7.520 32.07 .442 .318
.503 .503 .2500 7.2400 7.520 27.62 .571 .405
.503 .503 .3333 6.4676 7.520 .24.68 .680 .473
.503 .503 .5000 5.2800 7.520 20.15 I .832 .543
.503 .503 .6667 4.4816 7.520 17.10 .942 .570
************************************************************ Storage Maximum
.503 .503 .7333 4.2402 7.520 16.18 I .981 .576
****************************************************************************
.503 .503 .8333 3.8792 7.520 14.80 1.019 .565
.503 .503 1.0000 3.5000 7.520 13.35 1.104 .567
.503 .503 2.0000 2.0000 7.520 7.63 Qpeak < Qallow
LONG LAKE SUBDIVISION - TRACT 1, PHASES 3 & 4
POND C - PONDPACK OUTPUT
Elev. vs. Flow
STAGE-DISCHARGE FUNCTION FOR OUTLET
x
W
Hydrograph for 2-year Design Storm
POND C IN vs OUT
w
U
3
0
LL
Plotted Curves
OUTLET POND C
Plotted Curves
WETLAND IN 2-yr
WETLAND OUT 2-yr
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Flow (cfs)
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Time (hrs)
LONG LAKE SUBDIVISION - TRACT 1, PHASES 3 & 4
POND C - PONDPACK OUTPUT
Hydrograph for 10-year Design Storm
POND C IN vs OUT
N
U
3
0
LL
Hydrograph for 100-year Design Storm.
POND C IN vs OUT
U
3
0
LL
1
1
t
3.0 3.5 4.0
Plotted Curves
WETLAND IN 10-yr
WETLAND OUT 10-yr
Plotted Curves
WETLAND IN 100-yr
WETLAND OUT 100-yr
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Time (hrs)
0.5 1.0 1.5 2.0 2.5
Time (hrs)
LONG LAKE SUBDIVISION - TRACT 1, PHASES 3 & 4
POND C - PONDPACK OUTPUT
Volume vs. Time
MINIMUM DRAIN TIME - Runoff from first 1" Rainfall
U
(0
a?
E
0
Plotted Curves
- MDRAIN OUT
Time (hrs)
0 10 20 30 40 50 60 70
Project Name: Long Lake Subdivision
City/State: Raleigh, NC
POND D - TRACT 1, PHASE 2 (Dry Pond)
Project #: 201113.2
Date: 14-Aug-02
Rational
C Fraction
IA Total
Area (ac) Pervious
(ac) Impervious
(ac)
Pervious Area 0.22 0 5.64 5.64 0
Impervious 0.95 1.00 5.31 0 5.31
Totals 10.95 5.64 5.31
% Impervious Surface Area = 48 %
1-Inch Runoff Volume Calculation
Using the runoff volume calculations in the "Simple Method" as described by Schueler (1987)
Rv = 0.05 + 0.009(1) where, Rv = Runoff coefficient, in./in.
I = Percent impervious
Rv = 0.49 in./in.
Total runoff volume from 1-inch precipitation:
Runoff volume, S = (Design rainfall) (Rv) (Drainage Area)
S = 0.444 acre-ft
19335 cu. ft.
Elevation for Min. Required Storage= 384.35 feet
Runoff storage provided = 0.443 ac-ft
Riser structure crest elevation = 384.4 feet
Runoff storage provided = 0.452 ac-ft
LONG LAKE SUBDIVISION - TRACT 1, PHASE 2
POND D - PONDPACK OUTPUT
Job File: K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND D_TRACT 1 PH 2-DRY POND.PPW
Rain Dir: I:\ENGFILE\HAESTAD\PPW RAINFALL DATA\WAKE CO\
--------------------------
--------------------------
JOB TITLE
--------------------------
--------------------------
LONG LAKE SUBDIVISION - TRACT 1
Pond D - Tract 1, Phase 2
Dry Pond Design
Raleigh, North Carolina
W&R Project #201113
The Modified Rational Method was used to determine peak discharge rates for the 2-year,
10-year and 100-year design storm events for the Raleigh/Durham, North Carolina area and
size the detention storage for the dry detention pond due to the small drainage area
(±10.95 acres). The Modified Rational Method is an extension of the rational method for
rainfalls with durations greater than the time of concentration. The method was modified
so that the concepts of the rational method (peak discharge) could be used to develop
hydrographs for storage routing. The Modified Rational Method within PondPack calculates
the storage volume for hydrographs of rainfalls of various durations to determine the
critical duration for the design storm as the one requiring the greatest detention
storage volume. This critical duration is used to calculate the discharge rate and
volume of water that is routed through the pond structure. The hydrograph developed
maintains the calculated volume and adjusts the peak discharge rate accordingly. Thus,
the peak discharge for the Modified Rational Method is less than the calculated Rational
Method.
The rainfall data used in this design was taken from the Intensity-Duration-Frequency
Table for the Raleigh area published in the City of Raleigh Stormwater Management Design
Manual. The post-development time of concentration was set at 5 minutes to account for
the piped drainage system.
Pond D is an extended dry detention basin that is designed to capture the volume of
runoff from the first 1-inch of rainfall and slowly release it over a 48 to 72 hour
period. The slow release of the runoff from the first 1-inch of rainfall also meets the
requirements for diffuse flow through the riparian buffer. In addition, the dry basin is
designedd to pass the 100-year design storm through the riser/barrel outlet structure of
the pond.
Pond D Design Summary:
Required Storage Volume = 0.444 ac-ft (19,335 cu ft)
Storage Volume Provided = 0.452 ac-ft (19,690 cu ft)
Top of Dam = 386.5'
Calculated Freeboard for the 10-yr design storm = 1.45 ft
Calculated Freeboard for the 100-yr design storm = 1.27 ft
Outlet Structure:
¦ 48" RCP Riser structure with crest at 384.4'
¦ 24" RCP Barrel; 60 ft length; Inverts at 381' and 379.39'
¦ Floating Skimmer device with constant Q = 0.09 cfs for draw-down
LONG LAKE SUBDIVISION - TRACT 1, PHASE 2
POND D - PONDPACK OUTPUT
Table of Contents
********************r* MASTER SUMMARY **********************
Watershed....... Mod. Rational Grand Summary ........ 1.01
Master Network Summary ............. 1.02
**rr*****************,t RAINFALL DATA **t********************
2-yr IDF Table.. 2-yr
I-D-F Table ........................ 2.01
10-yr IDF Table 10-yr
I-D-F Table ........................ 2.01
100-yr IDF Table 100-yr
I-D-F Table ........................ 2.02
*****t**************** TC CALCULATIONS ******************r**
AREA POND D..... Tc Calcs ........................... 3.01
*********************** POND VOLUMES ******r****************
DRY POND........ Vol: Elev-Area ..................... 4.01
******************** OUTLET STRUCTURES *********************
OUTLET 1........ Outlet Input Data 5.01
Composite Rating Curve ............. 5.04
*********************** POND ROUTING ***********************
DRY POND........ Pond E-V-Q Table ................... 6.01
****************** RATIONAL METHOD CALCS *******************
AREA POND D..... C and Area ......................... 7.01
AREA POND D..... Rational Peak Qs ................... 7.02
AREA POND D..... 2-yr Mod. Rational Storm Calcs ..... 7.03
AREA POND D..... 10-yr Mod. Rational Storm Calcs .... 7.04
AREA POND D..... 100-yr Mod. Rational Storm Calcs ... 7.05
LONG LAKE SUBDIVISION - TRACT 1, PHASE 2
POND D - PONDPACK OUTPUT
Type.... Mod. Rational Grand Summary Page 1.01
Name.... Watershed
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND D_TRACT 1 PH 2-DRY POND.PPW
************************************************************************
************************************************************************
* MODIFIED RATIONAL METHOD
* ---- Grand Summary For All Storm Frequencies ----
* *
* *
************************************************************************
************************************************************************
Q = CiA * Units Conversion; Where Conversion = 43560 / (12 * 3600)

... Area =
......... 10.950 acres
............
...... Tc
............... = .0833
....... hrs
...........
.............
................ ......... ............ ...... ............... ..................
VOLUMES
Freq. Adjusted Duration I Qpeak Allowable Inflow Storage
years 'C'
---------------- hrs
--------- in/hr
------------ cfs
------ cfs I
----------- --- ac-ft
------- ac-ft
-----------
2 .590 .5833 2.4904 16.21 13.00 .781 .423
10 .590 .6000 3.3747 21.97 18.00 1.089 .581
100 .590 .7333 4.2402 27.60 21.00 1.673 .964
LONG LAKE SUBDIVISION - TRACT 1, PHASE 2
POND D PONDPACK OUTPUT
Type.... Master Network Summary Page 1.02
Name.... Watershed
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND D_TRACT 1 PH 2-DRY POND.PPW
MASTER DESIGN STORM SUMMARY
Default Network Design Storm File, ID RAL_IDF.IDQ Raleigh IDF
Rainfall
Ret urn Event Type IDF File IDF
--
- ID
--------
--- ---------
2-yr ---------------
I-D-F Table -------- --
RAL IDF --
-
2-yr I DF Table
10-yr I-D-F Table RAL_IDF 10-yr IDF Table
100-yr I-D-F Table RAL_IDF 100-yr IDF Table
MASTER NETWORK SUMMARY
Modified Rational Method Network
(*Node=Outfall; +Node=Diversion;)
(Trun= HYG Truncation: Blank=None; L=Left; R=Rt; LR=L eft&Rt)
Max
Return HYG Vol Qpeak Qpeak Max WSEL Pond Storage
Node ID Type Event ac-ft Trun hrs cfs
-
- ft
-
------ ac-ft
------------
-----
AREA -------
POND D ----- ----
AREA ------ ---------- --
2 .782 --------- -
.0833 ----
-
16.21 -
AREA POND D AREA 10 1.089 .0833 21.97
AREA POND D AREA 100 1.673 .0833 27.60
DRY POND IN POND 2 .781 .0900 16.21
DRY POND IN POND 10 1.088 .0900 21.97
DRY POND IN POND 100 1.673 .0900 27.60
DRY POND OUT POND 2 .474 .5800 15.63 384.94 .543
DRY POND OUT POND 10 .780 .5900 21.96 385.05 .562
DRY POND OUT POND 100 1.363 .7300 27.03 385.23 .598
*OUT (LAKE) JCT 2 .474 .5800 15.63
*OUT (LAKE) JCT 10 .780 .5900 21.96
*OUT (LAKE) JCT 100 1.363 .7300 27.03
LONG LAKE SUBDIVISION - TRACT 1, PHASE 2
POND D - PONDPACK OUTPUT
Type.... I-D-F Table Page 2.01
Name.... 2-yr IDF Table Tag: 2-yr Event: 2 yr
File.... I:\ENGFILE\HAESTAD\PPW RAINFALL DATA\WAKE CO\RAL_IDF.IDF
Title... 2-yr Storm from City of Raleigh IDF Table
Storm... 2-yr IDF Table Tag: 2-yr
Rainfall-Intensity-Duration Curve
Time, hrs Intens., in/hr
.0833
.1670
.2500
.3330
.5000
.6670
.8330
1.0000
1.5000
2.0000
3.0000
6.0000
12.0000
24.0000
5.7600
4.7600
4.0400
3.4700
2.7000
2.2800
1.9400
1.7000
1.2200
.9500
.7100
.4400
.2600
.1500
Type.... I-D-F Table
Name.... 10-yr IDF Table Tag: 10-yr Event: 10 yr
File.... I:\ENGFILE\HAESTAD\PPW RAINFALL DATA\WAKE CO\RAL_IDF.IDF
Title... 10-yr Event Table from City of Raleigh IDF Table
Storm... 10-yr IDF Table Tag: 10-yr
Rainfall-Intensity-Duration Curve
Time, hrs Intens., in/hr
.0833 7.5000
.1670 6.1300
.2500 5.2500
.3300 4.6400
.5000 3.7100
.6670 3.1500
.8330 2.7100
1.0000 2.4100
1.5000 1.7400
2.0000 1.3700
3.0000 1.0200
6.0000 .6500
12.0000 .3900
24.0000 .2200
LONG LAKE SUBDIVISION - TRACT 1, PHASE 2
POND D - PONDPACK OUTPUT
Type.... I-D-F Table Page 2.02
Name.... 100-yr IDF Table Tag: 100-yr Event: 100 yr
File.... I:\ENGFILE\HAESTAD\PPW RAINFALL DATA\WAKE CO\RAL IDF.IDF
Title... 100-yr Event from City of Raleigh IDF Table
Storm... 100-yr IDF Table Tag: 100-yr
Rainfall-Intensity-Duration Curve
Time, hrs Intens., in/hr
.0833
.1670
.2500
.3330
.5000
.6670
.8330
1.0000
1.5000
2.0000
3.0000
6.0000
12.0000
24.0000
9.7200
8.4000
7.2400
6.4700
5.2800
4.4800
3.8800
3.5000
2.5300
2.0000
1.5000
.9600
.5700
.3300
LONG LAKE SUBDIVISION - TRACT 1, PHASE 2
POND D - PONDPACK OUTPUT
Type.... Tc Calcs
Name.... AREA POND D
Page 3.01
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND D_TRACT 1 PH 2 -DRY POND.PPW
........................................................................
........................................................................
TIME OF CONCENTRATION CALCULATOR
........................................................................
........................................................................
Segment #1: Tc: User Defined
Description: Tc = 5 minutes
Segment #1 Time: .0833 hrs
------------------------------------------------------------------------
-------------------------
-------------------------
Total Tc: .0833 hrs
Calculated Tc < Min.Tc:
Use Minimum Tc...
Use Tc = .0833 hrs
-------------------------
-------------------------
LONG LAKE SUBDIVISION - TRACT 1, PHASE 2
POND D - PONDPACK OUTPUT
Type.... Vol: Elev-Area
Name.... DRY POND
Page 4.01
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND D_TRACT 1 PH 2-DRY POND.PPW
Elevation Planimeter Area Al+A2+sgr(A1*A2) Volume Volume Sum
(ft) (sq.in) (acres)
----- (acres)
---------------- (ac-ft)
---------- (ac-ft)
-------------
------------
381.00 ----------------
----- .0903 .0000 .000 .000
382.00 ----- .1170 .3101 .103 .103
384.00 ----- .1614 .4158 .277 .381
385.50 ----- .1979 .5380 .269 .650
POND VOLUME EQUATIONS
* Incremental volume computed by the Conic Method for Reservoir Volumes.
Volume = (1/3) * (EL2-ELI) * (Areal + Areal + sq.rt.(Areal*Area2))
where: EL1, EL2 = Lower and upper elevations of the increment
Areal,Area2 = Areas computed for EL1, EL2, respectively
Volume = Incremental volume between ELl and EL2
LONG LAKE SUBDIVISION - TRACT 1, PHASE 2
POND D PONDPACK OUTPUT
Type.... Outlet Input Data
Name.... OUTLET 1
Page 5.01
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND D_TRACT 1 PH 2-DRY POND.PPW
REQUESTED POND WS ELEVATIONS:
Min. Elev.= 381.00 ft
Increment = .10 ft
Max. Elev.= 385.50 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
User Defined Table SK ---> TW .000 385.500
Stand Pipe RI ---> CV 384.400 385.500
Culvert-Circular CV ---> TW 381.000 385.500
TW SETUP, DS Channel
LONG LAKE SUBDIVISION TRACT 1, PHASE 2
POND D - PONDPACK OUTPUT
Type.... Outlet Input Data
Name.... OUTLET 1
Page 5.02
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND D_TRACT 1 PH 2-DRY POND.PPW
OUTLET STRUCTURE INPUT DATA
Structure ID = SK
Structure Type = User Defined Table
------------------------------------
ELEV-FLOW RATING TABLE
Elev, ft Flow, cfs
--------- ---------
381.00 .09
385.50 .09
Structure ID = RI
Structure Type = Stand Pipe
-----------------
# of Openings -------------
= 1 ------
Invert Elev. = 384.40 ft
Diameter = 4.0000 ft
Orifice Area = 12.5664 sq.ft
Orifice Coeff. _ .600
Weir Length = 12.57 ft
Weir Coeff. = 3.100
K, Submerged = .000
K, Reverse = 1.000
Kb,Barrel = .000000 (per ft of full flow)
Barrel Length = .00 ft
Mannings n = .0000
LONG LAKE SUBDIVISION - TRACT 1, PHASE 2
POND D - PONDPACK OUTPUT
Type.... Outlet Input Data
Name.... OUTLET 1
Page 5.03
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND D_TRACT 1 PH 2-DRY POND.PPW
OUTLET STRUCTURE INPUT DATA
Structure ID = CV
Structure Type = Culvert-Circular
-
--
----------
-----------------
No. Barrels -
---
--
= 1
Barrel Diameter = 2.0000 ft
Upstream Invert = 381.00 ft
Dnstream Invert = 379.39 ft
Horiz. Length = 50.00 ft
Barrel Length = 50.03 ft
Barrel Slope = .03220 ft/ft
OUTLET CONTROL DATA...
Mannings n = .0130
Ke = .5000
Kb = .012411
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) = 1.144
T2 ratio (HW/D) = 1.291
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 = 383.29 ft ---> Flow = 15.55 cfs
At T2 Elev = 383.58 ft ---> Flow = 17.77 cfs
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
LONG LAKE SUBDIVISION - TRACT 1, PHASE 2
POND D - PONDPACK OUTPUT
Type.... Composite Rating Curve
Name.... OUTLET 1
Page 5.04
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND D_TRACT 1 PH 2-DRY POND.PPW
***** COMPOSITE OUTFLOW SUMMARY ****
WS Elev, Total Q Notes
-------- -------- ------ -- Converge --- ----- --- --------------
Elev. Q TW El ev Error
ft cfs ft +/-ft Contributing Structures
--------
381.00 -------
.09 ------
Free -- -----
Outfall ----
SK -----
(no ---
Q: --------------
RI,CV)
381.10 .09 Free Outfall SK (no Q: RI,CV)
381.20 .09 Free Outfall SK (no Q: RI,CV)
381.30 .09 Free Outfall SK (no Q: RI,CV)
381.40 .09 Free Outfall SK (no Q: RI,CV)
381.50 .09 Free Outfall SK (no Q: RI,CV)
381.60 .09 Free Outfall SK (no Q: RI,CV)
381.70 .09 Free Outfall SK (no Q: RI,CV)
381.80 .09 Free Outfall SK (no Q: RI,CV)
381.90 .09 Free Outfall SK (no Q: RI,CV)
382.00 .09 Free Outfall SK (no Q: RI,CV)
382.10 .09 Free Outfall SK (no Q: RI,CV)
382.20 .09 Free Outfall SK (no Q: RI,CV)
382.30 .09 Free Outfall SK (no Q: RI,CV)
382.40 .09 Free Outfall SK (no Q: RI,CV)
382.50 .09 Free Outfall SK (no Q: RI,CV)
382.60 .09 Free Outfall SK (no Q: RI,CV)
382.70 .09 Free Outfall SK (no Q: RI,CV)
382.80 .09 Free Outfall SK (no Q: RI,CV)
382.90 .09 Free Outfall SK (no Q: RI,CV)
383.00 .09 Free Outfall SK (no Q: RI,CV)
383.10 .09 Free Outfall SK (no Q: RI,CV)
383.20 .09 Free Outfall SK (no Q: RI,CV)
383.30 .09 Free Outfall SK (no Q: RI,CV)
383.40 .09 Free Outfall SK (no Q: RI,CV)
383.50 .09 Free Outfall SK (no Q: RI,CV)
383.60 .09 Free Outfall SK (no Q: RI,CV)
383.70 .09 Free Outfall SK (no Q: RI,CV)
383.80 .09 Free Outfall SK (no Q: RI,CV)
383.90 .09 Free Outfall SK (no Q: RI,CV)
384.00 .09 Free Outfall SK (no Q: RI,CV)
384.10 .09 Free Outfall SK (no Q: RI,CV)
384.20 .09 Free Outfall SK (no Q: RI,CV)
384.30 .09 Free Outfall SK (no Q: RI,CV)
384.40 .09 Free Outfall SK (no Q: RI,CV)
384.50 1.32 Free Outfall SK, RI,CV
384.60 3.57 Free Outfall SK, RI,CV
384.70 6.49 Free Outfall SK, RI,CV
LONG LAKE SUBDIVISION - TRACT 1, PHASE 2
POND D - PONDPACK OUTPUT
Type.... Composite Rating Curve
Name.... OUTLET 1
Page 5.05
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND D_TRACT 1 PH 2-DRY POND.PPW
***** COMPOSITE OUTFLOW SUMMARY ****
WS Elev, Total Q Notes
-------- -------- ------ -- Converge -------------------------
Elev. Q TW Elev Error
ft cfs ft +/-ft
---- Contributing Structures
--------------------------
--------
384.80 -------
9.94 -----
Free --- -
Outfall SK,RI,CV
384.90 13.86 Free Outfall SK,RI,CV
385.00 18.20 Free Outfall SK,RI,CV
385.10 26.40 Free Outfall SK,RI,CV
385.20 26.87 Free Outfall SK,RI,CV
385.30 27.33 Free Outfall SK,RI,CV
385.40 27.78 Free Outfall SK,RI,CV
385.50 28.22 Free Outfall SK,RI,CV
LONG LAKE SUBDIVISION - TRACT 1, PHASE 2
POND D PONDPACK OUTPUT
Type.... Pond E-V-Q Table Page 6.01
Name.... DRY POND
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND D_TRACT 1 PH 2 -DRY POND.PPW
LEVEL POOL ROUTING DATA
HYG Dir = K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\
Inflow HYG file = NONE STORED - DRY POND IN 2-yr
Outflow HYG file = NONE STORED - DRY POND OUT 2-yr
Pond Node Data = DRY POND
Pond Volume Data = DRY POND
Pond Outlet Data = OUTLET 1
No Infiltration
INITIAL CONDITIONS
Starting WS Elev = 381.00 ft
Starting Volume = .000 ac- ft
Starting Outflow = .09 cfs
Starting Infiltr. _ .00 cfs
Starting Total Qout= .09 cfs
Time Increment = .0100 hrs
Elevation Outflow Storage Area Infilt. Q Total 2S/t + O
ft cfs ac-ft acres cfs cfs cfs
------------
381.00 ------------
.09 ---------
.000 ---- --------
.0903 -----------
.00 ------------
.09 ----------
.09
381.10 .09 .009 .0928 .00 .09 22.25
381.20 .09 .019 .0954 .00 .09 45.02
381.30 .09 .028 .0979 .00 .09 68.40
381.40 .09 .038 .1006 .00 .09 92.42
381.50 .09 .048 .1032 .00 .09 117.08
381.60 .09 .059 .1059 .00 .09 142.39
381.70 .09 .070 .1086 .00 .09 168.35
381.80 .09 .081 .1114 .00 .09 194.96
381.90 .09 .092 .1142 .00 .09 222.25
382.00 .09 .103 .1170 .00 .09 250.23
382.10 .09 .115 .1191 .00 .09 278.79
382.20 .09 .127 .1211 .00 .09 307.85
382.30 .09 .139 .1232 .00 .09 337.41
382.40 .09 .152 .1253 .00 .09 367.48
382.50 .09 .164 .1274 .00 .09 398.06
382.60 .09 .177 .1296 .00 .09 429.16
382.70 .09 .190 .1317 .00 .09 460.78
382.80 .09 .204 .1339 .00 .09 492.91
382.90 .09 .217 .1361 .00 .09 525.59
383.00 .09 .231 .1383 .00 .09 558.79
383.10 .09 .245 .1405 .00 .09 592.53
383.20 .09 .259 .1428 .00 .09 626.82
LONG LAKE SUBDIVISION - TRACT 1, PHASE 2
POND D - PONDPACK OUTPUT
Type.... Pond E-V-Q Table Page 6.02
Name.... DRY POND
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND D_TRACT 1 PH 2-DRY POND.PPW
LEVEL POOL ROUTING DATA
HYG Dir = K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\
Inflow HYG file = NONE STORED - DRY POND IN 2-yr
Outflow HYG file = NONE STORED - DRY POND OUT 2-yr
Pond Node Data = DRY POND
Pond Volume Data = DRY POND
Pond Outlet Data = OUTLET 1
No Infiltration
INITIAL CONDITIONS
---------
Starting ------------
WS Elev = ---------
381.00 ---
ft -
Starting Volume = .000 ac- ft
Starting Outflow = .09 cfs
Starting Infiltr. _ .00 cfs
Starting Total Qout= .09 cfs
Time Increment = .0100 hrs
Elevation Outflow Storage Area Infilt. Q Total 2S/t + 0
ft cfs ac-ft acres cfs
--
-- cfs
------------ cfs
----------
------------
383.30 -------------
.09 --------
.273 ---- --------
.1450 ------
-
.00 .09 661.64
383.40 .09 .288 .1473 .00 .09 697.02
383.50 .09 .303 .1496 .00 .09 732.95
383.60 .09 .318 .1520 .00 .09 769.44
383.70 .09 .333 .1543 .00 .09 806.50
383.80 .09 .349 .1566 .00 .09 844.11
383.90 .09 .365 .1590 .00 .09 882.31
384.00 .09 .381 .1614 .00 .09 921.08
384.10 .09 .397 .1637 .00 .09 960.42
384.20 .09 .413 .1661 .00 .09 1000.33
384.30 .09 .430 .1684 .00 .09 1040.78
384.40 .09 .447 .1708 .00 .09 1081.83
384.50 1.32 .464 .1732 .00 1.32 1124.68
384.60 3.57 .482 .1756 .00 3.57 1169.12
384.70 6.49 .499 .1780 .00 6.49 1214.82
384.80 9.94 .517 .1804 .00 9.94 1261.63
384.90 13.86 .535 .1829 .00 13.86 1309.50
385.00 18.20 .554 .1853 .00 18.20 1358.38
385.10 26.40 .572 .1878 .00 26.40 1411.74
385.20 26.87 .591 .1903 .00 26.87 1457.96
385.30 27.33 .611 .1928 .00 27.33 1504.77
385.40 27.78 .630 .1954 .00 27.78 1552.19
385.50 28.22 .650 .1979 .00 28.22 1600.22
LONG LAKE SUBDIVISION - TRACT 1, PHASE 2
POND D - PONDPACK OUTPUT
Type.... C and Area
Name.... AREA POND D
Page 7.01
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND D_TRACT 1 PH 2-DRY POND.PPW
Title... Revised Drainage Area - 6/10/02
RATIONAL C COEFFICIENT DATA
.........................................................................
.........................................................................
Revised Drainage Area - 6/10/02
-------------------------------------------------------------------------
Area C x Area
Soil/Surface Description C acres acres
-------------------------------- -------- ---------- ----------
Impervious Area .9500 5.310 5.045
Pervious Area .2500 5.640 1.410
WEIGHTED C & TOTAL AREA ---> .5895 10.950 6.455
.........................................................................
LONG LAKE SUBDIVISION - TRACT 1, PHASE 2
POND D - PONDPACK OUTPUT
Type.... Rational Peak Q's
Name.... POST DEV POND D
Page 7.02
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND D_TRACT 1 PH 2-DRY POND.PPW
SUMMARY OF RATIONAL METHOD PEAK DISCHARGES
Q = CiA * Units Conversion; Where Conversion = 43560 / (12 * 3600)
Rational Storms: RAL IDF.IDQ Raleigh IDF
Tag
----- Freq
------ File
------
------ IDF Curve
-----------
-----
100-yr 100 RAL_ID F.IDF 100-yr IDF Table
Tc = .0833 hrs

Tag
Freq
C
C adj ----------
C --------
I -----------
Area
Peak Q
(years) factor final in/hr acres cfs
-
-----
2-yr ------
2 -----
.590 ------
1.000 ----------
I .590 --------
5.7600 -----------?
10.950 I ------
---
37.49
10-yr 10 .590 1.000 .590 7.5000 10.950 48.82
100-yr 100 .590 1.000 .590
---------- 9.7200
-------- 10.950
----------- 63.27
LONG LAKE SUBDIVISION - TRACT 1, PHASE 2
POND D - PONDPACK OUTPUT
Type.... Mod. Rational Storm Calcs Page 7.03
Name.... AREA POND D Tag: 2-yr Event: 2 yr
File.... K.\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND D_TRACT 1 PH 2-DRY POND.PPW
Storm... 2-yr IDF Table Tag: 2-yr
MODIFIED RATIONAL METHOD
---- Summary for Single Storm Frequency ----
Q = CiA * Units Conversion; Where Conversion = 43560 / (12 * 3600)
RETURN
------- FREQUENCY:
---------- 2 yr -C'
---------- Adjustment
----------- = 1.000Allowable
------------------- Q = 13.00
--------- cfs
----------
Hydrograph Storm Duration, Td = .5833 hrs Tc = .0833 hrs
Hydrograph File:
................. 2-yr
..........
...........
........
...........
.........
..........
....... .......... .......... ........... ........ ........... ...................
VOLUMES
Wtd. Adjusted Duration Intens. Area Qpeak Inflow Storage
'C' 'C' hrs in/hr acres cfs ac-ft ac-ft
--
------
-------
.590 ----------
.590 ----------
.0833 -----------
5.7600 --------
10.950 -------- --
37.49 . ---------
.258 -
-
.169
.590 .590 .1667 4.7640 10.950 31.01 I .427 .293
.590 .590 .2500 4.0400 10.950 26.30 I .543 .364
.590 .590 .3333 3.4685 10.950 22.58 I .622 .398
.590 .590 .5000 2.7000 10.950 17.57 .726 .413
************************************************************ Storage Maximum
.590 .590 .5833 2.4904 10.950 16.21 I .781 .423
****************************************************************************
.590 .590 .6667 2.2808 10.950 14.85 .818 .415
.590 .590 .8333 1.9395 10.950 12.62 Qpeak < Qallow
LONG LAKE SUBDIVISION - TRACT 1, PHASE 2
POND D - PONDPACK OUTPUT
Type.... Mod. Rational Storm Calcs Page 7.04
Name.... AREA POND D Tag: 10-yr Event: 10 yr
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND D_TRACT 1 PH 2-DRY POND.PPW
Storm... 10-yr IDF Table Tag: 10-yr
MODIFIED RATIONAL METHOD
---- Summary for Single Storm Frequency ----
Q = CiA * Units Conversion; Where Conversion = 43560 / (12 * 3600)
RETURN
------ FREQUENCY:
----------- 10 yr 'C' Adjustment = 1.000Allowable
---------------------------------------- Q = 18.00
---------- cfs
---------
Hydrograph Storm Duration, Td = .6000 hrs Tc = .0833 hrs
Hydrograph File:
................. 10-yr
.........
...........
........
............
..........
.........
...... ........... ......... ........... ........ ............ ...................
VOLUMES
Wtd. Adjusted Duration Intens. Area Qpeak I Inflow Storage
'C' 'C' hrs in/hr acres cfs
--------- -- ac-ft
---------- ac-ft
---------
------
.590 -----------
.590 ---------
.0833 -----------
7.5000 --------
10.950 48.82 .336 .212
.590 .590 .1667 6.1355 10.950 39.93 .550 .364
.590 .590 .2500 5.2500 10.950 34.17 .706 .458
.590 .590 .3333 4.6218 10.950 30.08 I .829 .519
.590 .590 .5000 3.7100 10.950 24.15 .998 .564
************************************************************ Storage Maximum
.590 .590 .6000 3.3747 10.950 21.97 1.089 .581
****************************************************************************
.590 .590 .6667 3.1511 10.950 20.51 1.130 .572
.590 .590 .8333 2.7094 10.950 17.64 Qpeak < Qallow
LONG LAKE SUBDIVISION - TRACT 1, PHASE 2
POND D - PONDPACK OUTPUT
Type.... Mod. Rational Storm Calcs Page 7.05
Name.... AREA POND D Tag: 100-yr Event: 100 yr
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\POND D_TRACT 1 PH 2-DRY POND.PPW
Storm... 100-yr IDF Table Tag: 100-yr
MODIFIED RATIONAL METHOD
---- Summary for Single Storm Frequency ----
Q = CiA * Units Conversion; Where Conversion = 43560 / (12 * 3600)
RETURN
------- FREQUENCY:
---------- 100 yr
--------- 'C' Adjustment =
------------------ 1.000Allowable
-------------- Q = 21.00
----------- cfs
-------
Hydrograph Storm Duration, Td = .7333 hrs Tc = .0833 hrs
Hydrograph File:
................. 100-yr
.........
...........
.......
..............
..........
........
....... .......... ......... ........... ....... .............. ..................
VOLUMES
Wtd. Adjusted Duration Intens. Area Qpeak Inflow Storage
'C' 'C' hrs in/hr acres cfs
-- ac-ft
-
--
--- ac-ft
--------
-------
.590 ----------
.590 ---------
.0833 -----------
9.7200 -------
10.950 ---------- -
63.27 -
---
.436 .291
.590 .590 .1667 8.4053 10.950 54.71 .754 .537
.590 .590 .2500 7.2400 10.950 47.12 .974 .684
.590 .590 .3333 6.4676 10.950 42.10 1.160 .798
.590 .590 .5000 5.2800 10.950 34.37 1.420 .914
.590 .590 .6667 4.4816 10.950 29.17 I 1.607 .956
************************************************************ Storage Maximum
.590 .590 .7333 4.2402 10.950 27.60 1.673 .964
****************************************************************************
590 .590 .8333 3.8792 10.950 25.25 1.739 .944
590 .590 1.0000 3.5000 10.950 22.78 I 1.883 .943
590 .590 2.0000 2.0000 10.950 13.02 Qpeak < Qallow

O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
w
m
U
O
LL
LONG LAKE SUBDIVISION - TRACT 1, PHASE 2
POND D - PONDPACK OUTPUT
Elev. vs. Flow
STAGE-DISCHARGE FUNCTION FOR OUTLET 1
Hydrograph for 2-yr Design Storm
DRY POND IN vs OUT
Plotted Curves
OUTLET 1
Plotted Curves
DRY POND IN 2-yr
DRY POND OUT 2-yr
2 4 6 8 10 12 14 16 18 20 22 24 26 28
Flow (cfs)
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Time (hrs)
LONG LAKE SUBDIVISION - TRACT 1, PHASE 2
POND D - PONDPACK OUTPUT
Hydrograph for 10-year Design Storm
DRY POND IN vs OUT
N
U
3
LL

O
O
O
O
O N
U
o
O

O
Hydrograph for 100-year Design Storm
DRY POND IN vs OUT
Plotted Curves
DRY POND IN 10-yr
DRY POND OUT 10-yr
Plotted Curves
DRY POND IN 100-yr
DRY POND OUT 100-yr
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Time (hrs)
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Time (hrs)
LONG LAKE SUBDIVISION - TRACT 1, PHASE 2
POND D - PONDPACK OUTPUT
Volume vs. Time
MINIMUM DRAIN TIME - Runoff from first 1" Rainfall
0.4

0.3
U

N
E

0.2

0.1
0
O
O
O
O
O
O
O
O
0
0.01

0 10 20 30 40 50 60 7C
Time (hrs)
Plotted Curves
- M DRAIN OUT
Project Name: Long Lake Subdivision - Tract 2, Phase 2 Project #: 201113.1
City/State: Raleigh, NC Date: 23-Jul-02
Table 1.1 Surface Area to Drainage Area Ratio for Permanent Pool Sizing for 85% Pollutant
Removal Efficiencv in the Piedmont

4
O
0
0
0
0
0
O

% Impervious
Cover Permanent Pool Dept
3.0 4.0 5.0 6.0 h (feet)
7.0 8.0 9.0
10 0.59 0.49 0.43 0.35 0.31 0.29 0.26
20 0.97 0.79 0.70 0.59 0.51 0.46 0.44
30 1.34 1.08 0.97 0.83 0.70 0.64 0.62
40 1.73 1.43 1.25 1.05 0.90 0.82 0.77
50 2.06 1.73 1.50 1.30 1.09 1.00 0.92
60 2.40 2.03 1.71 1.51 1.29 1.18 1.10
70 2.88 2.40 2.07 1.79 1.54 1.35 1.26
80 3.36 2.78 2.38 2.10 1.86 1.60 1.42
90 3.74 3.10 2.66 2.34 2.11 1.83 1.67
Source: NCDENR/DWQ Stormwater Best Management Practices, pg. 5, April 1999
POND E (Constructed Wetland in Tract 2 - FES #42)
Impervious
(sq ft) (ac) Pervious
(sq ft) (ac) Total
(ac)
Pervious Area 0 0 135743 3.12 3.12
Streets 67117 1.54 0 0.00 1.54
Sidewalks 10735 0.25 0 0.00 0.25
Lots (impervious %) 75600 1.74 0 0.00 1.74
Totals 153452 3.52 135743 3.12 6.64
% Impervious Surface Area = 53 %
Surface Area of Permanent Pool:
Assumed depth = 3 feet
SA/DA ratio = 2.16 % From Table 1.1
Minimum pond surface area (SA) = ( DA * SA/DA ratio)/100
SA = 0.144 acres
6252 sq. ft.
Normal pool elevation = 384.25 feet
Surface area provided = 0.144 acres
6291 sq. ft.
1-Inch Runoff Volume Calculation
Using the runoff volume calculations in the "Simple Method" as described by Schueler (1987)
Rv = 0.05 + 0.009(1) where, Rv = Runoff coefficient, in./in.
I = Percent impervious
Rv = 0.528 in./in.
Total runoff volume from 1-inch precipitation:
Runoff volume, S = (Design rainfall) (Rv) (Drainage Area)
S = 0.292 acre-ft
12714 cu. ft.
Riser structure crest elevation = 386.5 feet
Runoff storage provided = 0.3'0 ac-ft
16117 cu. ft.
O
0\01\01-110\01113\HH\SWMP\PulteStormwaterCalcs Wetlands Jun02.xls
LONG LAKE SUBDIVISION - TRACT 2, PHASE 2
POND E - PondPack Output for Wetland Design
Job File: K:\01\01-110\01113\H&H\SWMP\PPW WETLANDS\TRACT 2 WETLAND A.PPW
Rain Dir: I:\ENGFILE\HAESTAD\PPW RAINFALL DATA\WAKE CO\
--------------------------
--------------------------
JOB TITLE
LONG LAKE SUBDIVISION - TRACT 2, PHASE 2
POND E - Extended Detention Wetland at FES #42
Raleigh, North Carolina
W&R Project #201113.1
The Modified Rational Method was used to determine peak discharge rates for the 1-year,
2-year, 10-year and 100-year design storm events for the Raleigh/Durham, North Carolina
area and size the detention storage for the dry detention pond due to the small drainage
area (±6.6 acres). The Modified Rational Method is an extension of the rational method
for rainfalls with durations greater than the time of concentration. The method was
modified so that the concepts of the rational method (peak discharge) could be used to
develop hydrographs for storage routing. The Modified Rational Method within PondPack
calculates the storage volume for hydrographs of rainfalls of various durations to
determine the critical duration for the design storm as the one requiring the greatest
detention storage volume. This critical duration is used to calculate the discharge rate
and volume of water that is routed through the pond structure. The hydrograph developed
maintains the calculated volume and adjusts the peak discharge rate accordingly. Thus,
the peak discharge for the. Modified Rational Method is less than the calculated Rational
Method.
The rainfall data used in this design was taken from the Intensity-Duration-Frequency
Table for the Raleigh area published in the City of Raleigh Stormwater Management Design
0 Manual. The post-development time of concentration was set at 5 minutes to account for
the piped drainage system.
O
O Pond E is an extended detention wetland that is designed to capture the volume of runoff
from the first 1-inch of rainfall and slowly release it over a 48 to 72 hour period. In
addition, the wetland is designed to pass the 100-year design storm through the
riser/barrel outlet structure of the pond.
O
O
O
O
O
O
O
O
Pond E Design Highlights:
Normal Pool Elevation = 384.25'
Required Surface Area 0.144 acres (6252 sq. ft.)
Surface Area Provided = 0.144 acres (6292 sq. ft.)
Required Storage Volume = 0.292 ac-ft
Storage Volume Provided = 0.370 ac-ft at 386.5'
Top of Dam = 388'
Calculated Freeboard for the 10-yr design storm = 1.01 ft
Calculated Freeboard for the 100-yr design storm = 0.86 ft
Outlet Structure:
¦ 48" RCP Riser structure with crest at 386.5'
¦ 48 linear feet of 24" RCP Barrel with inverts at 377.48' and 377'
¦ 1.75" Circular Orifice at 384.25' for extended draw-down
LONG LAKE SUBDIVISION - TRACT 2, PHASE 2
POND E - PondPack Output for Wetland Design
Table of Contents
****************r***** MASTER SUMMARY ******r***x***********
Watershed....... Mod. Rational Grand Summary ........ 1.01
Master. Network Summary ............. 1.02
*******r************** RAINFALL DATA ***********************
1-yr IDF Table.. 1-yr
I-D-F Table ........................ 2.01
2-yr IDF Table.. 2-yr
I-D-F Table ........................ 2.01
10-yr IDF Table 10-yr
I-D-F Table ........................ 2.02
100-yr IDF Table 100-yr
I-D-F Table ........................ 2.02
********************** TC CALCULATIONS *************** ******
TRACT 2 AREA#1.. Tc Calcs ........................... 3.01
*********************** POND VOLUMES ***************** ******

WETLAND A....... Vol: Elev=Area ..................... 4.01
4 ******************** OUTLET STRUCTURES *************** ******
O OUTLET A........ Outlet Input Data .................. 5.01
O Composite Rating Curve ............. 5.04
O *********************** POND ROUTING ***************** ******
O
WETLAND A....... Pond E-V-Q Table ................... 6.01
O
O ****************** RATIONAL METHOD CALCS ************* ******
0 TRACT 2 AREA A.. 1-yr
Mod. Rational Storm Calcs .......... 7.01
0
O TRACT 2 AREA A.. 2-yr
Mod. Rational Storm Calcs .......... 7.02

TRACT 2 AREA A.. 10-yr
Mod. Rational Storm Calcs .......... 7.03
O
TRACT 2 AREA A.. 100-yr
Mod. Rational Storm Calcs .......... 7.04
O
TRACT 2 AREA#1.. C and Area ......................... 7.05
O
0
LONG LAKE SUBDIVISION - TRACT 2, PHASE 2
POND E - PondPack Output for Wetland Design
O
O
O
O
O
O
O
O
Type.... Mod. Rational Grand Summary Page 1.01
Name.... Watershed
File.... K:\01\01-110\01113\H&H\SWMP\PPW WETLANDS\TRACT 2 WETLAND A.PPW
************************************************************************
************************************************************************
* *
* *
* MODIFIED RATIONAL METHOD
* ---- Grand Summary For All Storm Frequencies ----
*
* *
************************************************************************
************************************************************************
Q CiA * Units Conversion; Where Conversion = 43560 / (12 * 3600)
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
Area =
.. 6.650 acres
..........
........ Tc
.............. = .0833
........ hrs
..........
................
................ ......
.
......... .
........... ........ .............. ....................
VOLUMES
Freq. Adjusted Duration I Qpeak Allowable Inflow Storage
years 'C'
---------------- hrs
--------- in/hr
----------- cfs
-------- cfs
---------- --- ac-ft
-------- ac-ft
----------
1 .608 .4000 2.5289 10.30 8.70 .341 .167
2 .608 .4000 3.1611 12.88 10.90 .426 .208
10 .608 .4167 4.1659 16.97 15.00 I .584 .274
100 .608 .5667 4.9606 20.21 18.00 .946 .463
LONG LAKE SUBDIVISION - TRACT 2, PHASE 2
POND E - PondPack Output for Wetland Design
Type.... Master Network Summary Page 1.02
Name.... Watershed
File.... K:\01\01-110\01113\H&H\SWMP\PPW WETLANDS\TRACT 2 WETLAND A.PPW
MASTER DESIGN STORM SUMMARY
Default Network Design Storm File, ID RAL_IDF.IDQ Raleigh IDF
Return Event
------------
. 1-yr
2-yr
10-yr
100-yr

0
0
0
0
0
0
0
0
0
0
0
0
Rainfall
Type
--------------- IDF
---- File
---- IDF ID
----------------
I-D-F Table RAL_ IDF 1-yr IDF Table
I-D-F Table RAL IDF 2-yr IDF Table
I-D-F Table RAL_ IDF 10-yr IDF Table
I-D-F Table RAL IDF 100-yr IDF Table
MASTER NETWORK SUMMARY
Modified Rational. Method Network
(*Node=Outfall; +Node=Diversion;)
(Trun= HYG Truncation: Blank=None; L=Left; R=Rt; LR=Left&Rt)
Max
Return HYG Vol Qpeak Qpeak Max WSEL Pond Storage
Node ID Type Event ac-ft Trun hrs
- cfs ft ac-ft
-----------------
*OUTFALL A ----
JCT ------ --
1 --------
.163 -- --
------
.4300 --------
.11 -------- ------------
*OUTFALL A JCT 2 .221 .4600 3.77
*OUTFALL A JCT 10 .379 .4300 13.63
*OUTFALL A JCT 100 .740 .5600 20.11
TRACT 2 AREA A AREA 1 .340 .0833 10.30
TRACT 2 AREA A AREA 2 .425 .0833 12.88
TRACT 2 AREA A AREA 10 .584 .0833 16.97
TRACT 2 AREA A AREA 100 .946 .0833 20.21
WETLAND A IN POND 1 .340 .0900 10.30
WETLAND A IN POND 2 .425 .0900 12.88
WETLAND A IN POND 10 .584 .0900 16.97
WETLAND A IN POND 100 .946 .0900 20.21
WETLAND A OUT POND 1 .163 .4300 .11 386.33 .337
WETLAND A OUT POND 2 .221 .4600 3.77 386.71 .406
WETLAND A OUT POND 10 .379 .4300 13.63 386.99 .460
WETLAND A OUT POND 100 .740 .5600 20.11 387.14 .488
E
LONG LAKE SUBDIVISION - TRACT 2, PHASE 2
POND E - PondPack Output for Wetland Design
Type.... I-D-F Table Page 2.01
Name.... 1-yr IDF Table Tag: 1-yr Event: 1 yr
File.... I:\ENGFILE\HAESTAD\PPW RAINFALL DATA\WAKE CO\RAL_IDF.IDF
Title... 1-yr Design Storm (80% of 2-yr)
Storm... 1-yr IDF Table. Tag: 1-yr
Rainfall-Intensity-Duration Curve
0
0
0
0
0
0
0
0
0
O
O
O
0
0
O
O
O
O
O
0
O
O
O
Time, hrs
----------- Intens., in/hr
-----------
.0833 4.6080
.1670 3.8080
.2500 3.2320
.3330 2.7760
.5000 2.1600
.6670 1.8240
.8330 1.5520
1.0000 1.3600
1.5000 .9760
2.0000 .7600
3.0000 .5680
6.0000 .3520
12.0000 .2080
24.0000 .1200
Type.... I-D-F Table
Name.... 2-yr IDF Table Tag: 2-yr Event: 2 yr
File.... I:\ENGFILE\HAESTAD\PPW RAINFALL DATA\WAKE CO\RAL_IDF.IDF
Title... 2-yr Storm from City of Raleigh IDF Table
Storm... 2-yr IDF Table Tag: 2-yr
Rainfall-Intensity-Duration Curve
Time, hrs
----------- Intens., in/hr
-----------
.0833 5.7600
.1670 4.7600
.2500 4.0400
.3330 3.4700
.5000 2.7000
.6670 2.2800
.8330 1.9400
1.0000 1.7000
1.5000 1.2200
2.0000 .9500
3.0000 .7100
6.0000 .4400
12.0000 .2600
24.0000 .1500
LONG LAKE SUBDIVISION - TRACT 2, PHASE 2
POND E - PondPack Output for Wetland Design
Type.... I-D-F Table Page 2.02
Name.... 10-yr IDF Table Tag: 10-yr Event: 10 yr
File.... I:\ENGFILE\HAESTAD\PPW RAINFALL DATA\WAKE CO\RAL_IDF.IDF
Title... 10-yr Event Table from City of Raleigh IDF Table
Storm... 10-yr IDF Table Tag: 10-yr
Rainfall-Intensity-Duration Curve

Time, hrs
.0833
.1670
.2500
.3300
.5000
.6670
.8330
1.0000
1.5000
2.0000
3.0000
6.0000.
12.0000
24.0000
Intens., in/hr
0
O
O
O
0
0
0
0
O
O
O
0
0
7.5000
6.1300
5.2500
4.6400
3.7100
3.1500
2.7100
2.4100
1.7400
1.3700
1.0200
.6500
.3900
.2200
Type.... I-D-F Table
Name.... 100-yr IDF Table Tag: 100-yr Event: 100 yr
File.... I:\ENGFILE\HAESTAD\PPW RAINFALL DATA\WAKE CO\RAL_IDF.IDF
Title... 100-yr Event from City of Raleigh IDF Table
Storm... 100-yr IDF Table Tag: 100-yr
Rainfall-Intensity-Duration Curve
Time, hrs
.0833
.1670
.2500
.3330
.5000
.6670
.8330
1.0000
1.5000
2.0000
3.0000
6.0000
12.0000
24.0000
Intens., in/hr
9.7200
8.4000
7.2400
6.4700
5.2800
4.4800
3.8800
3.5000
2.5300
2.0000
1.5000
.9600
.5700
.3300
LONG LAKE SUBDIVISION - TRACT 2, PHASE 2
POND E - PondPack Output for Wetland Design
Type.... Tc Calcs
Name.... TRACT 2 AREA#1
Page 3.01
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\TRACT 2 WETLAND A.PPW
........................................................................
........................................................................
TIME OF CONCENTRATION CALCULATOR
........................................................................
........................................................................
n
L -A
Segment #1: Tc: User Defined
Description: Tc = 5 minutes
Segment #1 Time: .0833 hrs
------------------------------7-----------------------------------------
-------------------------
-------------------------
Total Tc: .0833 hrs
O
O
O
O
O
O
O
0
O
O
O
O
O
O
O
O
0
Calculated Tc < Min.Tc:
Use Minimum Tc...
Use Tc = .0833 hrs
LONG LAKE SUBDIVISION - TRACT 2, PHASE 2
POND E - PondPack Output for Wetland Design
Type.... Vol: Elev-Area Page 4.01
Name.... WETLAND A
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\TRACT 2 WETLAND A.PPW
Elevation Planimeter Area Al+A2+sgr(Al*A2) Volume Volume Sum
(ft) (sq.in) (acres) (acres) (ac-ft) (ac-ft)
. ------------ ------------- -------- ----------------- --------- -------------
384.25 ----- .1444 .0000 .000 .000
385.00 ----- .1570 .4520 .113 .113
386.00 ----- .1740 .4963 .165 .278
387.00 ----- .1920 .5488 .183 .461
388.00 ----- .2107 .6038 .201 .663
ID
POND VOLUME EQUATIONS

* Incremental volume computed by the Conic Method for Reservoir Volumes.

Volume = (1/3) * (EL2 -ELl) * (Areal + Area2 + sq.rt.(Areal*Area2))
where: EL1, EL2 = Lower and upper elevations of the increment
Areal,Area2 = Areas computed for EL1, EL2, respectively
Volume = Incremental volume between ELl and EL2

O
O
O
O
O
O
O
O
O
O
O
O
O
0
LONG LAKE SUBDIVISION TRACT 2, PHASE 2
POND E - PondPack Output for Wetland Design
0
O
O
O
O
O
0
O
O
O
0
0
Type.... Outlet Input Data Page 5.01
Name.... OUTLET A
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\TRACT 2 WETLAND A.PPW
REQUESTED POND WS ELEVATIONS:
Min. Elev.= 384.25 ft
Increment = .10 ft
Max. Elev.= 388.00 ft
Spot Elevations, ft
384.25.
**********************************************
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
----------------- ---- ------- --------- ---------
Stand Pipe RI ---> CV 386.500 388.000
Orifice-Circular OR ---> CV 384.250 388.000
Culvert-Circular CV ---> TW 377.480 388.000
TW SETUP, DS Channel
LONG LAKE SUBDIVISION TRACT 2, PHASE 2
POND E - PondPack Output for Wetland Design
Type.... Outlet Input Data Page 5.02
Name.... OUTLET A
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\TRACT 2 WETLAND A.PPW
OUTLET STRUCTURE INPUT DATA
0
O
O
O
O
O
O
O
O
O
0
Structure ID = RI.
Structure Type
----------------- = Stand Pipe
-------------
------
# of Openings = 1
Invert Elev. = 386.50 ft
Diameter = 4.0000 ft
Orifice Area = 12.5664 sq.ft
Orifice Coeff. _ .600
Weir Length = 12.57 ft
Weir Coeff. = 3.100
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. = 384.25 ft
Diameter = .1458 ft
Orifice Coeff. _ .600
LONG LAKE SUBDIVISION - TRACT 2, PHASE 2
POND E - PondPack Output for Wetland Design
Type.... Outlet Input Data Page 5.03
Name.... OUTLET A
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\TRACT 2 WETLAND A.PPW
OUTLET STRUCTURE INPUT DATA
0

0
O
O
O
O
O
O
O
O
O
O
O
0
0
Structure ID = CV
Structure Type =
-
-- Culvert-Circular
-----------------
---------------
-
No. Barrels = 1
Barrel Diameter = 2.0000 ft
Upstream Invert = 377.48 ft
Dnstream Invert = 377.00 ft
Horiz. Length = 48.00 ft
Barrel Length = 48.00 ft
Barrel Slope = .01000 ft/ft
OUTLET CONTROL DATA ...
Mannings n = .0130
Ke = .5000 (forward entrance loss)
Kb = .012411 (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) = 1.155
T2 ratio (HW/D) = 1.302
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 = 379.79 ft ---> Flow = 15.55 cfs
At T2 Elev = 380.08 ft ---> Flow = 17.77 cfs
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
LONG LAKE SUBDIVISION - TRACT 2, PHASE 2
POND E - PondPack Output for Wetland Design
Type.... Composite Rating Curve
Name.... OUTLET A
Page 5.04
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\TRACT 2 WETLAND A.PPW
***** COMPOSITE OUTFLOW SUMMARY ****
u
•
0
O
O
O
O
O

O
O
O
O
•
WS Elev, Total Q Notes
-------- -------- ------ -- Converge ----------- --- -----------
Elev. Q TW Elev Error
ft cfs ft +/-ft Contributing Structures
-
--------
384.25 -------
.00 ------
Free -- ----- -
Outfall ------------------------
(no Q: RI,OR,CV)
384.30 .00 Free Outfall OR,CV (no Q: RI)
384.40 .02 Free Outfall OR,CV (no Q: RI)
384.50 .03 Free Outfall OR,CV (no Q: RI)
384.60 .04 Free Outfall OR,CV (no Q: RI)
384.70 .05 Free Outfall OR,CV (no Q: RI)
384.80 .06 Free Outfall OR,CV (no Q: RI)
384.90 .06 Free Outfall OR,CV (no Q: RI)
385.00 .07 Free Outfall OR,CV (no Q: RI)
385.10 .07 Free Outfall OR,CV (no Q: RI)
385.20 .08 Free. Outfall OR,CV (no Q: RI)
385.30 .08 Free Outfall OR,CV (no Q: RI)
385.40 .08 Free Outfall OR,CV (no Q: RI)
385.50 .09 Free Outfall OR,CV (no Q: RI)
385.60 .09 Free Outfall OR,CV (no Q: RI)
385.70 .09 Free Outfall OR,CV (no Q: RI)
385.80 .10 Free Outfall OR,CV (no Q: RI)
385.90 .10 Free Outfall OR,CV (no Q: RI)
386.00 .10 Free Outfall OR,CV (no Q: RI)
386.10 .11 Free Outfall OR,CV (no Q: RI)
386.20 .11 Free Outfall OR,CV (no Q: RI)
386.30 .11 Free Outfall OR,CV (no Q: RI)
386.40 .12 Free Outfall OR,CV (no Q: RI)
386.50 .12 Free Outfall OR,CV (no Q: RI)
386.60 1.35 Free Outfall RI,OR,CV
386.70 3.61 Free Outfall RI,OR,CV
386.80 6.53 Free Outfall RI,OR,CV
386.90 9.98 Free Outfall RI,OR,CV
387.00 13.90 Free Outfall RI,OR,CV
387.10 18.24 Free Outfall RI,OR,CV
387.20 22.95 Free Outfall RI,OR,CV
387.30 28.01 Free Outfall RI,OR,CV
387.40 33.40 Free Outfall RI,OR,CV
387.50 39.08 Free Outfall RI,OR,CV
387.60 45.00 Free Outfall RI,CV (no Q: OR)
387.70 46.95 Free Outfall RI,CV (no Q: OR)
387.80 47.22 Free Outfall RI,CV (no Q: OR)
387.90 47.48 Free Outfall RI,CV (no Q: OR)
388.00 47.74 Free Outfall RI,CV (no Q: OR)
LONG LAKE SUBDIVISION - TRACT 2, PHASE 2
POND E - PondPack Output for Wetland Design
Type.... Pond E-V-Q Table. Page 6.01
Name.... WETLAND A
File.... K:\01\01-110\01113\H&H\SWMP\PPW WETLANDS\TRACT 2 WETLAND A.PPW
LEVEL POOL ROUTING DATA
HYG Dir = K:\01\01-110\01113\H&H\SWMP\PPW WETLANDS\
Inflow HYG file = NONE STORED - WETLAND A IN 1-yr
Outflow HYG file = NONE STORED - WETLAND A OUT 1-yr
Pond Node Data = WETLAND A
Pond Volume Data = WETLAND A
Pond Outlet Data = OUTLET A
No Infiltration
INITIAL CONDITIONS
---
---------------------
Starting WS Elev = --------
384.25 --
ft
Starting Volume = .000 ac-ft
Starting Outflow = .00 cfs
Starting Infiltr. _ .00 cfs
Starting Total Qout= .00 cfs
Time Increment _ .0100 hrs
O
O
O
O
O
O
O
0
Elevation Outflow Storage Area Infilt. Q Total 2S/t + O
ft cfs ac-ft acres cfs
-------- cfs
------------ cfs
----------
-----------
384.25 ------------
.00 -----------
.000 -----------
.1444 ---
.00 .00 .00
384.30 .00 .007 .1452 .00 .00 17.52
384.40 .02 .022 .1469 .00 .02 52.89
384.50 .03 .037 .1485 .00 .03 88.65
384.60 .04 .052 .1502 .00 .04 124.79
384.70 .05 .067 .1519 .00 .05 161.36
384.80 .06 .082 .1536 .00 .06 198.33
384.90 .06 .097 .1553 .00 .06 235.71
385.00 .07 .113 .1570 .00 .07 273.51
385.10 .07 .129 .1587 .00 .07 311.70
385.20 .08 .145 .1603 .00 .08 350.30
385.30 .08 .161 .1620 .00 .08 389.31
385.40 .08 .177 .1637 .00 .08 428.73
385.50 .09 .194 .1654 .00 .09 468.55
385.60 .09 .210 .1671 .00 .09 508.78
385.70 .09 .227 .1688 .00 .09 549.43
385.80 .10 .244 .1705 .00 .10 590.49
385.90 .10 .261 .1723 .00 .10 631.98
386.00 .10 .278 .1740 .00 .10 673.88
386.10 .11 .296 .1758 .00 .11 716.19
386.20 .11 .314 .1775 .00 .11 758.95
386.30 .11 .331 .1793 .00 .11 802.13
386.40 .12 .349 .1811 .00 .12 845.74
LONG LAKE SUBDIVISION - TRACT 2, PHASE 2
POND E - PondPack Output for Wetland Design
Type.... Pond E-V-Q Table Page 6.02
Name.... WETLAND A
File.... K:\01\01-110\01113\H&H\SWMP\PPW WETLANDS\TRACT 2 WETLAND A.PPW
LEVEL POOL ROUTING DATA
HYG Dir = K:\01\01-110\01113\H&H\SWMP\PPW WETLANDS\
Inflow HYG file = NONE STORED - WETLAND A IN 1-yr
Outflow HYG file = NONE STORED - WETLAND A OUT 1-yr
Pond Node Data = WETLAND A
Pond Volume Data = WETLAND A
Pond Outlet Data = OUTLET A
No Infiltration
0 INITIAL CONDITIONS
--------- ------------- ------- -----
Starting WS Elev _ 384.25 ft
Starting Volume _ .000 ac-ft
Starting Outflow _ .00 cfs
Starting Infiltr. _ .00 cfs
Starting Total Qout= .00 cfs
Time Increment _ .0100 hrs
O
O
O
O
O
O
O
O
0
•
•
Elevation Outflow Storage Area Infilt. Q Total 2S/t + 0
ft cfs ac-ft acres cfs
--- cfs
------------ cfs
----------
-----------
386.50 ------------
.12 ------------
.368 ----------
.1829 --------
.00 .12 889.79
386.60 1.35 .386 .1847 .00 1.35 935.49
386.70 3.61 .405 .1865 .00 3.61 982.66
386.80 6.53 423 .1883 .00 6.53 1030.94
386.90 9.98 .442 .1902 .00 9.98 1080.20
387.00 13.90 .461 .1920 .00 13.90 1130.36
387.10 18.24 .481 .1938 .00 18.24 1181.37
387.20 22.95 .500 .1957 .00 22.95 1233.21
387.30 28.01 .520 .1975 .00 28.01 1285.85
387.40 33.40 .540 .1994 .00 33.40 1339.27
387.50 39.08 .560 .2012 .00 39.08 1393.43
387.60 45.00 .580 .2031 .00 45.00 1448.27
387.70 46.95 .600 .2050 .00 46.95 1499.60
387.80 47.22 .621 .2069 .00 47.22 1549.70
387.90 47.48 .642 .2088 .00 47.48 1600.27
388.00 47.74 .663 .2107 .00 47.74 1651.29
LONG LAKE SUBDIVISION - TRACT 2, PHASE 2
POND E - PondPack Output for Wetland Design
Type.... Mod. Rational Storm Calcs Page 7.01
Name.... TRACT 2 AREA A Tag: 1-yr Event: 1 yr
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\TRACT 2 WETLAND A.PPW
Storm... 1-yr IDF Table Tag: 1-yr
MODIFIED RATIONAL METHOD
---- Summary for Single Storm Frequency ----
Q = CiA * Units Conversion; Where Conversion = 43560 / (12 * 3600)
RETURN FREQUENCY:
----------------- 1 yr 'C'
---------- Adjustment
----------- = 1.000Allowable
------------------- Q = 8.70
--------- cfs
----------
Hydrograph Storm Duration, Td = .4000 hrs Tc = .0833 hrs
Hydrograph File:

.................
..
..........
..1.yr ....
...........
...........
.......
.......
............
............
.........
.........
..........
...........
VOLUMES
Wtd. Adjusted Duration Intens. Area Qpeak Inflow Storage
'C' 'Cl hrs in/hr acres cfs
-
-
-- -- ac-ft
--------- ac-ft
----------
-----------------
.608 .608 ----------
.0833 -----------
4.6080 -------
6.650 ---
-
-
18.77 .129 .069
.608 .608 .1667 3.8112 6.650 15.53 I .214 .124
.608 .608 .2500 3.2320 6.650 13.17 .272 .152
.608 .608 .3333 2.7748 6.650 11.30 .311 .162
O
O
O
O
O
O
O
O
0
************************************************************ Storage Maximum
.608 .608 .4000 2.5289 6.650 10.30 .341 .167
****************************************************************************
.608 .608 .5000 2.1600 6.650 8.80 .364 .154
.608 .608 .6667 1.8247 6.650 7.43 Qpeak < Qallow
LONG LAKE SUBDIVISION TRACT 2, PHASE 2
POND E - PondPack Output for Wetland Design
Type.... Mod. Rational Storm Calcs Page 7.02
Name.... TRACT 2 AREA A Tag: 2-yr Event: 2 yr
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\TRACT 2 WETLAND A.PPW
Storm... 2-yr IDF Table Tag: 2-yr
MODIFIED RATIONAL METHOD
---- Summary for Single Storm Frequency ----

CI
Q CiA * Units Conversion; Where Conversion = 43560 / (12 * 3600)
RETURN FREQUENCY:
----------------- 2 yr 'C'
---------- Adjustment
----------- = 1.000Allowable
------------------- Q = 10.90
---------- cfs
---------
Hydrograph Storm Duration, Td = .4000 hrs Tc = .0833 hrs
Hydrograph File: 2-yr
VOLUMES
Wtd. Adjusted Duration Intens. Area Qpeak Inflow Storage
-C' 'C' hrs in/hr acres cfs ac-ft
--------- ac-ft
----------
-----------------
.608 .608 ----------
.0833 -----------
5.7600 --------
6.650 -------- --
23.46 .162 .086
.608 .608 .1667 4.7640 6.650 19.41 I .267 .155
.608 .608 .2500 4.0400 6.650 16.46 I .340 .190
.608 .608 .3333 3.4685 6.650 14.13 .389 .202
************************************************************ Storage Maximum
.608 .608 .4000 3.1611 6.650 12.88 I .426 .208
****************************************************************************
.608 .608 .5000 2.7000 6.650 11.00 .454 .192
.608 .608 .6667 2.2808 6.650 9.29 Qpeak < Qallow
O
O
O
O
O
O
O
O
0
0
•
•
LONG LAKE SUBDIVISION - TRACT 2, PHASE 2
POND E - PondPack Output for Wetland Design
Type.... Mod. Rational Storm Calcs Page 7.03
Name.... TRACT 2 AREA A Tag: 10-yr Event: 10 yr
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\TRACT 2 WETLAND A.PPW
Storm... 10-yr IDF Table Tag: 10-yr
MODIFIED RATIONAL METHOD
---- Summary for Single Storm Frequency ----
Q CiA * Units Conversion; Where Conversion = 43560 / (12 * 3600)
RETURN
------ FREQUENCY:
----------- 10 yr 'C' Adjustment = 1.000Allowable
----------------------------------------- Q = 15.00
--------- cfs
---------
Hydrograph Storm Duration, Td = .4167 hrs Tc = .0833 hrs
Hydrograph File:
................. 10-yr
.........
...........
........
............
..........
.........
...... ........... ......... ........... ........ ............ ...................
VOLUMES
Wtd. Adjusted Duration Intens. Area Qpeak Inflow Storage
'C' 'C' hrs in/hr acres cfs ac-ft
---
--- ac-ft
---------
------
.608 -----------
.608 ---------
.0833 -----------
7.5000 --------
6.650 --------- --
30.55 -
---
.210 .107
.608 .608 .1667 6.1355 6.650 24.99 I .344 .189
.608 .608 .2500 5.2500 6.650 21.39 .442 .235
.608 .608 .3333 4.6218 6.650 18.83 .519 .260
************************************************************ Storage Maximum
.608 .608 .4167 4.1659 6.650 16.97 .584 .274
****************************************************************************
608 .608 .5000 3.7100 6.650 15.11 .624 .263
608 .608 .6667 3.1511 6.650 12.84 Qpeak < Qallow
O
O
O
O
O
O
O
O
O
O
0
•
LONG LAKE SUBDIVISION - TRACT 2, PHASE 2
POND E PondPack Output for Wetland Design
Type.... Mod. Rational Storm Calcs Page 7.04
Name.... TRACT 2 AREA A Tag: 100-yr Event: 100 yr
File.... K:\01\01-110\01113\H&H\SWMP\PPW_WETLANDS\TRACT 2 WETLAND A.PPW
Storm... 100-yr IDF Table Tag: 100-yr
MODIFIED RATIONAL METHOD
---- Summary for Single Storm Frequency ----
Q = CiA * Units Conversion; Where Conversion = 43560 / (12 * 3600)
RETURN
------- FREQUENCY:
---------- 100 yr
--------- 'C' Adjustment =
------------------ 1.000Allowable
-------------- Q = 18.00
---------- cfs
--------
Hydrograph Storm Duration, Td = .5667 hrs Tc = .0833 hrs
Hydrograph File:
................. 100-yr
.........
...........
.......
..............
..........
........
...... ........... ......... ........... ....... ............... ..................
VOLUMES
Wtd. Adjusted Duration Intens. Area Qpeak Inflow Storage
-C' 'C' hrs in/hr acres cfs
-
--- ac-ft
---------- ac-ft
--------
------
.608 -----------
.608 ---------
.0833 -----------
9.7200 -------
6.650 --------
-
39.59 .273 .149
.608 .608 .1667 8.4053 6.650 34.24 .472 .286
.608 .608 .2500 7.2400 6.650 29.49 I .609 .361
.608 .608 .3333 6.4676 6.650 26.35 I .726 .416
.608 .608 .5000 5.2800 6.650 21.51 .889 .455
************************************************************ Storage Maximum
.608 .608 .5667 4.9606 6.650 20.21 .946 .463
****************************************************************************
n
-A
.608 .608 .6667 4.4816 6.650 18.26 1.006 .448
.608 .608 .8333 3.8792 6.650 15.80 Qpeak < Qallow
O
O
O
O
O
O
0
0
LONG LAKE SUBDIVISION - TRACT 2, PHASE 2
POND E - PondPack Output for Wetland Design
O
O
C11
O
O
O
O
O
0
•
Type.... C and Area
Name.... TRACT 2 AREA#1
Page 7.05
File.... K:\01\01-110\01113\H&H\SWMP\PPW WETLANDS\TRACT 2 WETLAND A.PPW
RATIONAL C COEFFICIENT DATA
.........................................................................
.........................................................................
Area C x Area
Soil/Surface Description C acres acres
--------------------------------
Streets --------
.9500 ----------
1.540 ----------
1.463
Sidewalk .9500 .250 .238
Lots (impervious .9500 1.740 1.653
Pervious .2200 3.120 .686
WEIGHTED C & TOTAL AREA --->
.................................
................................. .6075
............
............ 6.650
.............
............. 4.040
...............
...............
LONG LAKE SUBDIVISION - TRACT 2, PHASE 2
POND E - PondPack Output for Wetland Design
Elev. vs. Flow
STAGE-DISCHARGE FUNCTION FOROUTLET A
O
O
O
O
O
O
0
W
N
U
3
0
LL
Hydrograph for 1-yr Design Storm
WETLAND IN vs OUT
Plotted Curves
- OUTLET A
Plotted Curves
WETLAND A IN 1-yr
WETLAND A OUT 1-yr
0 10 20 30 40 50
Flow (cfs)
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Time (hrs)
LONG LAKE SUBDIVISION - TRACT 2, PHASE 2
POND E - PondPack Output for Wetland Design
Hydrograph for 2-yr Design Storm
WETLAND A IN vs OUT
O
O
O
O
0
a
U
3
0
LL
11
10
v 9
3
LL 8
1
0
0.0
Hydrograph for 10-yr Design Storm
WETLAND IN ?s OUT
I
3.0 3.5 4.0
Plotted Curves
WETLAND A IN 2-yr
WETLANDA OUT 2-yr
Plotted Curves
WETLAND A IN 10-yr
WETLAND A OUT 10-yr
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Time (hrs)
0.5 1.0 1.5 2.0 2.5
Time (hrs)
LONG LAKE SUBDIVISION - TRACT 2, PHASE 2
POND E - PondPack Output for Wetland Design
Hydrograph for 100-yr Design Storm
WETLAND IN vs OUT
N
U
3
0
Volume os. Time
MINIMUM DRAIN TIME - Runoff from first 1" Rainfall
O
O
O
40
0.30 .. .. _.I ... ...

0.25
_
I t a
l- _
0.20 ...
w

E 0.15 -
o
> -.
...
0.10
0.05 ... E ). v

0 10 20 30 40 50 60 70
Time (hrs)
Plotted Curves
WETLAND A IN 100-yr
WETLAND A OUT 100-yr
Plotted Curves
MIN DRAIN OUT

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Time (hrs)