19970694 Ver 1_Stormwater Info_20070720

q~- ot,9~ v3
BASS, NIXON & KENNEDY, INC., CONSULTING ENGINEERS
6310 CHAPEL HILL ROAD, SUITE 250, RALEIGH, NC 27607
919/851-4422 ^ FAX [phone]
July 18, 2007
N.C. Dept. of Environment and Natural Resources
Division of Water Quality
Attn: Ms. Annette Lucas
2321 Crabtree Boulevard, Suite 250
Raleigh, North Carolina 27604
Delivered to Division of Water Quality on July 19, 2007
Received by:
Print Name:
Subject: Colonial Grand at Wakefield Apartments
DWQ Project #970694
Dear Ms. Lucas:
fil'!3 -
J~JL ~, v 7.OOl
t)EIJk - ~NATFR UUALI i 1
WETIAhip"- P,+~D $TORP~!"!4TFR BRAhICH
The Colonial Grand at Wakefield Apartments is a proposed apartment project bordered
by Forest Pines Drive, Common Oaks Drive and Green Elm Lane located in the
Wakefield Commercial site in north Raleigh. The Wakefield Commercial site is located
west of US 1 and north of New Falls of Neuse Road in Wake County. It is our
understanding based on the May 4, 1999 letter of approval (DWQ Project #970694)
issued by the Division of Water Quality (DWQ) and based on our discussions with you
in February, 2007 that a stormwater plan must be submitted to the DWQ for review and
approval for all sites within the development. Although no wetland or stream buffer
impacts are proposed as part of the apartment site development, we have included
design information for the proposed stormwater management facilities for your review
and approval as requested. Two wet detention basins are proposed to provide 85%
TSS removal as required by the May 4, 1999 approval letter. The ponds have been
designed per our discussions in February of this year. The following information is
enclosed for your review and approval:
• Two copies of the preliminary construction drawings for the two proposed wet
detention basins (sheet Nos. C3.1, C3.2, C3.3, C3.4 and C3.5)
• Two copies of the DWQ Wet Detention Basin Worksheet for each basin
• Two copies of the design calculations with drainage area maps for the two wet
detention basins
• Two copies of the O&M Manual for the two basins
• Two copies of the original DWQ approval letter dated May 4, 1999

Please call me if you have any questions or comments or if you need additional
information concerning this matter.
Very truly yours,
BASS, NIXON & KENNEDY, INC.
~.~-,ti-~
David L. Dunn, PE
CC: Kevin Martin, S&EC
Jonathan Alexander, Colonial Properties Trust
2

-.-,
State of Borth Carolina
Department of Environment
and ~latura! Resources
Division of Water Quality
James B. Hunt, Jr., Governor
'J`Jayr2 McCevitt, Secretary
Kerr T. Stevens, Director
May 4, 1999
Wake Cnu:~ry
i7WQ Project # 970599
APPROVAL of 401 Water Quality Certification and ADDITIC}NAL CQNI7ITIOf~IS, WRP
Anvi) Investments, LLC
1005 High House Road
Cary, NC 27513
i~c:ti Si7S:
You have our approval, in accordance with the attached canditiotts and those fisted below, to place fill
material in 1555 linear feet of waters for the propose of developing the Wakefield Commercial site (n Wake at US I
and Falls of. the Neuse Road in Wake County, as you described in your application dated January 18. ! 999. Aftzr
rtvicwing your application, we have decided that this fill is cavcrrd by G:cneral Water Quality Certification
Vumbers 31 O1, 3102 and 310$. Those certifications allow you to use Nalianwide Permit Numbers 12, 14 and Z6
when the Corps of Engineers issues them. In addition, you should get arty other federal, start or lo.;al pcrr±tits Mforr
you go ahead with yew project including (but not limited ta) Sediment and Erosion {:ontrol, Coastal Stcumwater,
'ion-Disch: rgr snd Water Supply Watershed °rcgvlataons. 'F}tis approval will expire when the a:.cotnpartying a04 ar
CA?vI,A pet~rtit expires unless othctw(sc specified in the Genera) Certification.
Ibis approval is only valid for the purpose and design that you described in your application except as
modified below. If you change your project, you mast notify us and you may be required to seas! us a new
=rF! at:fl.^. for a ns:t~ ~e.^.:fi~a:io^. If the property is sold, the r:ew o~•nar must be gi :•er, a ccpy ;:f this Ccrtl`icacca
and approval letter and is thereby responsible for Complying with all ccndit!ut>s. If tuttzt wetlattJ lilts iur this
project (now or fn the future) exceed one acre, cornpensatory mitigation may be required as described to t5A NC-.C
?H .0506 {h}. For this approval to be valid, you must follow the condstions tistcd in tht attached certification and
;cny additional canditioru tistcd below.
i. C?etd nazi fications or similar mechanisms sha]1 be placed on alt lots with remaining jurisdictional
wetlands and wagers to notify the state in order to assure compl!ancc for future wetland and/or water
impact. These mechanisms shall be put to place within 3Q days of the Cato of this letter or the
--~.t~cuance n1 the •1(34 Perrmt {whichever is !at
:. "bn ad rd"ifonal condit~nn i< th2t a inn.. wriuen stxmwxicr pier. ~.vbieb mat $596 Y'SS!'tRtN1~0.l~1c!ud:n^_
protected stream buffers must be approved by DwQ before wetland (oi• stream) impacts occur, Atso.
bsf;;rr. s~y'building is ~ccupicd at the s~bjcet situ the stocmwater treatment facilities shall l;~ c~.~:.; uetc,! >
.tnd operattanat and tt,t, s[ormwpter rtiastagement plan oc implemented. ,,/'~
undcrstsrt at you ave ehoun ro contn ute tc e . et .,estoratton rogram in order :a xmpe:tsate
iJr tr~c~.P imFz•°ts to wetlands and/or streams. In accordance Kith ljA Iti~CAC 2R .Odfl?, this c;,ntribu:ia^ •a !l
satisfy our compensatory mitigation requirements under 15A NCAC 2H .0505(h). According to 15A NCAC .H
f?4Ct6fh), fee: of restoration will he required. Until the Wci(and Restoration Program rece:vcs and clrars }'uur check
:node ft:yabit .o: T,Ei•I1rK . vJetiand Kestoration Prnt?ram?: wetJana nr stmarn alt shall not o.:r,ur t~;r tton ctrl-it
should be contacted at 9(9-733•SU83 ext. 358 it you have any questions corccrning-the ~Vetlsnd Rcstoraticn
Pro¢ram. You have one month from the date of th,s Certification to make this paymtnt. For accnunting purpnaes.
this Ct:rtificatinn authorfze; the fill of 1555 feet of streams, in 030402 river and subbasin and 739 feet a[
zireztr~ rss:oration are r?juirt=d. Pfea>t ~ awarE tltst the Yf`ctlattd Restoration Frt;grttrtt;44'n.?; r::E~;
require round(a~ of acrragc amoanu to one-garirter sere increments LISA '~R .v503(b)).
;7
-<
~1
.~ r~
~~
~;~rtsipr. ~f V`l~tt:r^.,t::.5ty - 1:;;:•trp^rte^tal ~ii~7t".w 3rc~ch
ion•3;scharge Branc!t, r+401 Reedy Creek Fd., ~alcigtt, NC 27601 T~iephone 919.733.1786 FAX A 733.9~5y
An Equal Opportunity Affirmative Action Employer SO°/p reoyGadti 0°~ past consumer paper

If you do not accept any of the conditions of this ccrtitication, you may ask for an adjudicatory hearing. You
must act within 60 days of the date that you receive this letter. To stsk for s heating, send a written pCtition which
conforms to Chapter t Sd8 of the North Carolina Genera! Statutes to the flf~ce of
Administrative Eicarings, P.fl. Box 27447, Raleigh, N.C. 2761 t-7447. This cetvftcation and its conditiaru are final
and binding unless you ask for a hearing,
This Ictttr completes the review of the Division of Water Quality under Section 4~?I of the Clean Water Act.
if you have any questions, phase telephone JohrE Domey at 919-733-t78ti.
Attachment
~: Wilmington District Carps tsf Engineers
Carps of $ngineers Raleigh Fidd Office
Raleigh DWQ Regional flffce
Mr. lohn DotYtey
Central Hies
Ron Ferrell; Worland Restoration program
Todd St, lohn
Kenn Martin; S dr fi C
l
rr [CYCA~
97Q694.1tr

Project No. DWQ q ~ - ~ ~ q `~ V3 (to be provided by DWQ)
DIVISION OF WATER QUALITY - 401 WET DETENTION BASIN WORKSHEET
DWO Stormwater Management Plan Review:
A complete stormwater management plan submittal includes a wet detention basin worksheet for each basin,
design calculations, plans and specifications showing all basin and outlet structure details, and a fully executed
operation and maintenance agreement. An incomplete submittal package will result in a request for additional
information and will substantially delay final review and approval of the project.
L PROJECT INFORMATION (please complete the following information):
Project Name : Colonial Grand at Wakefield
Contact Person: David L Dunn. PE Phone Number: X919 1 851-4422
For projects with multiple basins, specify which basin this worksheet applies to: Basin No. 1
Basin Bottom Elevation 261.50 ft. (average elevation of the floor of the basin)
Permanent Pool Elevation 267.50 ft. (elevation of the orifice invert out)
Temporary Pool Elevation 268.32 ft. (elevation of the outlet structure invert in)
Permanent Pool Surface Area 17,492 sq. ft. (water surface area at permanent pool elevation)
Drainage Area 6.9 ac. (on-site and off-site drainage to the basin)
Impervious Area 4.3 ac. (on-site and off-site drainage to the basin)
Permanent Pool Volume 53,953 cu. ft. (combined volume of main basin and forebay)
Temporary Pool Volume 15,300 cu. ft. (volume detained on top of the permanent pool)
Forebay Volume 11,282 cu. ft.
SA/DA used 2.51 (surface area to drainage area ratio)
Diameter of Orifice 2.0 in. (draw down orifice diameter)
II. REQUIRED ITEMS CHECKLIST
The following checklist outlines design requirements per the Stormwater Best Management Practices manual
(N.C. Department of Environment, Health and Natural Resources, November 1995) and Administrative Code
Section: 15 A NCAC 2H .1008. Initial in the space provided to indicate the following design requirements have
been met and supporting documentation is attached. If a requiren~eiat has not bee~z »7et, attach an expla~zatio~~ of
wlay.
Aonlicants Initials
~L`~ The temporary pool controls runoff from the 1 inch storm event.
~za The basin length to width ratio is greater than 3:1. ~
~~ The basin side slopes are no steeper than 3:1.
+,`~ A submerged and vegetated perimeter shelf at less than 6:1 is provided.
~~ Vegetation to the permanent pool elevation is specified.
,7~~ An emergency drain is provided to drain the basin.
~L~ The permanent pool depth is between 3 and 6 feet (required minimum of 3 feet).
%~~~ The temporary pool draws down in 2 to 5 days.
~ ~~ The forebay volume is approximately equal to 20% of the total basin volume.
~i~ Sediment storage is provided in the permanent pool.
~~~ Access is provided for maintenance.
.y/~. ~~ A minimum 30-foot vegetative filter is provided at the outlet.
~~~ A site specific operation and maintenance (O&M) plan is provided.
~ ~ ~ A vegetation managementlmowing schedule is provided in the O&M plan.
~4~ Semi-annual inspections are specified in the O&M plan.
~ 4~ A debris check is specified in the O&M plan to be performed after every storm event.
>~~ A specific sediment clean-out benchmark is listed (elevation or depth) in O&M plan.
~~~ A responsible party is designated in the O&M plan.
FORM SWG100 09/97 Page 1 of 1

Project No. DWQ (to be provided by Di~Q~
DIVISION OF WATER QUALITY - 401 WET DETENTION BASIN WORKSHEET
DWO Stonnwater Management Plan Review:
A complete stonnwater management plan submittal includes a wet detention basin worksheet for each basin,
design calculations, plans and specifications showing all basin and outlet structure details, and a fully executed
operation and maintenance agreement. An incomplete submittal package will result in a request for additional
information and will substantially delay final review and approval of the project.
I. PROJECT INFORMATION (please complete the following information):
Project Name : Colonial Grand at Wakefield
Contact Person: David L. Dural, PE Phone Number: [phone]
For projects with multiple basins, specify which basin this worksheet applies to: Basin No. 2
Basin Bottom Elevation
Permanent Pool Elevation
Temporary Pool Elevation
Permanent Pool Surface Area
Drainage Area
Impervious Area
Permanent Pool Volume
Temporary Pool Volume
Forebay Volume
SA/DA used
Diameter of Orifice
269.50 ft. (average elevation of the floor of the basin)
275.00 ft. (elevation of the orifice invert out)
276.44 ft. (elevation of the outlet structure invert in)
15,821
sq. ft.
(water surface area at permanent pool elevation)
(on-site and off-site drainage to the basin)
(on-site and off-site drainage to the basin)
11.3 ac.
6.9 ac.
47,665 cu. ft.
24,593 cu. ft.
10,629 cu. ft.
(combined volume of main basin and forebay)
(volume detained on top of the permanent pool)
2.45 (surface area to drainage area ratio)
2.5 in. (draw down orifice diameter)
IL REQUIRED ITEMS CHECKLIST
The following checklist outlines design requirements per the Stormwater Best Management Practices manual
(N.C. Department of Environment, Health and Natural Resources, November 1995) and Administrative Code
Section: 15 A NCAC 2H .1008. Initial in the space provided to indicate the following design requirements have
been met and supporting documentation is attached. If a requirement has not been net, attach a~z explanation of
why.
Annlicants Initials
~- w> The temporary pool controls runoff from the 1 inch storm event.
~+-~ The basin length to width ratio is greater than 3:1.'-`'
~ L7 The basin side slopes are no steeper than 3:1.
i~~~ A submerged and vegetated perimeter shelf at less than 6:1 is provided.
~~ Vegetation to the permanent pool elevation is specified.
~~~ An emergency drain is provided to drain the basin.
~~~ The permanent pool depth is between 3 and 6 feet (required minimum of 3 feet).
?~~ The temporary pool draws down in 2 to 5 days.
~~ The forebay volume is approximately equal to 20% of the total basin volume.
~`~ Sediment storage is provided in the permanent pool.
~~ Access is provided for maintenance.
.vlti ~~ A minimum 30-foot vegetative filter is provided at the outlet.
~e.~ A site specific operation and maintenance (O&M) plan is provided.
~~ ~ A vegetation managementlmowing schedule is provided in the O&M plan.
~~ Semi-annual inspections are specified in the O&M plan.
~ L~ A debris check is specified in the O&M plan to be performed after every storm event.
,a;~ A specific sediment clean-out benchmark is listed (elevation or depth) in O&M plan.
J ~ A responsible party is designated in the O&M plan.
FORM SWG100 09/97 Page 1 of 1

G'l-o~9~ v3
BASS, NIXON & KENNEDY, INC., CONSULTING ENGINEERS
6310 CHAPEL HILL ROAD, SUITE 250, RALEIGH, NC 27607
919/851-4422 ^ FAX [phone]
STORMWATER OPERATIONS AND MAINTENANCE
MANUAL AND BUDGET
FOR
COLONIAL GRAND AT WAKEFIELD APARTMENTS
RALEIGH, NORTH CAROLINA
PRELIMINARY DRAFT
~t~~ ~,N
r a~'"`
~41~, ~` ~) :_
~FCI~ ;~
~4~ bj -
~~~s. •-
/ 4~.vd
~ ,`~~, .
1
7f,~~~7
July 18, 2007

BASS, NIXON & KENNEDY, INC., CONSULTING ENGINEERS
6310 CHAPEL HILL ROAD, SUITE 250, RALEIGH, NC 27607
919/851-4422 ^ FAX [phone]
STORMWATER OPERATIONS AND MAINTENANCE
MANUAL AND BUDGET
FOR
COLONIAL GRAND AT WAKEFIELD APARTMENTS
RALEIGH, NORTH CAROLINA
PRELIMINARY DRAFT
Owner:
Business Address:
Correspondence Address:
Colonial Realty, LP
2101 6~' Avenue North, Suite 750
Birmingham, AL 35203
2977 Crouse Lane
Burlington, NC 27215
Contact: Mark Barker, President
Phone: [phone]
Fax: [phone]
E-Mail: [e-mail]
1. BACKGROUND
The stormwater control measures serving the above referenced property consist of two
permanent wet detention basins designed according to the City of Raleigh and
NCDENR standards and requirements. The stormwater control measures are
described on construction drawings entitled "Colonial Grand at Wakefield Apartments",
as prepared by Bass, Nixon & Kennedy, Inc. and approved by the City of Raleigh.
1.1. Wet Detention Basins
Two wet detention basins will be required for the Colonial Grand at Wakefield
Apartments. Wet Detention Basin No. 1 is located on the south side of the
site and Wet Detention Basin No. 2 is located on the north side of the site.
The outlet structures for both wet detention basins consist of a 4'-0" diameter
extended base manhole. Wet Detention Basin No. 1 has a 2.0" diameter
drawdown orifice and Wet Detention Basin No. 2 has a 2.5" diameter
drawdown orifice. The outlet structure regulates the maximum water surface
elevation of the pond. The permanent pool elevation for Wet Detention Basin
Nos. 1 and 2 is 267.50 feet and 275.00 feet, respectively. The permanent
pool surface area for Wet Detention Basin No. 1 is approximately 17,490 SF,
Colonial Grand at Wakefield O&M Manual 1 of 10 ~ii8i2oo~

or 0.402 acres. The permanent pool surface area for Wet Detention Basin
No. 2 is approximately 15,820 SF, or 0.363 acres. The overall depth of Wet
Detention Basin No. 1 is 9.0 feet, with the bottom of the pond being at
elevation 262.00 and the top being at elevation 271.00. The overall depth of
Wet Detention Basin No. 2 is 12.5 feet, with the bottom of the pond being at
elevation 269.50 and the top being at elevation 282.00. Both basins will be
constructed with an earthen dam with an emergency spillway at the outlet end
of the basin
The sediment accumulation elevation that requires sediment cleanout of the
pond for Wet Detention Basin No. 1 is 266.10. The sediment accumulation
elevation that requires sediment cleanout of the pond for Wet Detention Basin
No. 2 is 273.60. This elevation is equal to a 75% reduction in the original
design depth of the basins. When sediment has accumulated at any location
in basin No. 1 to 266.10 or basin No. 2 to 273.60 (as determined by visual
inspection), accumulated sediment should be removed and pond bottom
should be restored to the condition shown on drawings entitled "Colonial
Grand at Wakefield Apartments", as approved by the City of Raleigh.
The rip-rap dissipator pad at the outlet for Wet Detention Basin No. 1 is
constructed using NCDOT Class B Rip-rap. Rip-rap replacement, as
required, should be as outlined below. Finally, healthy and vigorous
vegetation must be maintained (see attached seeding schedule) on the dam
embankment and slopes and mowed as outlined below.
2. MAINTENANCE AND INSPECTION SCHEDULE
2.1. General
2.1.1. During each inspection of the stormwater control measures, the attached
checklist shall be completed and filed with the maintenance records for
the measures.
2.1.2. Inspect basin side slopes and riprap dissipator pad below basin outlets
which discharge from pond. Reseed any eroded areas per the attached
seeding schedule and repair any displaced riprap by adding larger
diameter stone to the apron or by using a concrete slurry to bind smaller
stones together to increase their effective size and weight. Eroded rills
and gullies should be filled with topsoil, compacted and then reseeded
per the attached seeding schedule. Any concentrated stormwater flows
on the dam face or side slopes should be dispersed so that the surface
drainage will be spread out in thin layers as "sheet flow". The side slopes
associated with the pond require continual maintenance of the vegetative
cover. Any erosion on the embankment should be filled with topsoil,
compacted, and reseeded per the attached seeding schedule. Grass-
mowing, brush-cutting and removal of woody vegetation (including trees)
are necessary for the proper maintenance of the pond. Side slopes and
pond area should be mowed at least twice a year or when grass height
Colonial Grand at Wakefield O&M Manual 2 of 10 ~nsi2oo~

reaches six (6) inches, whichever comes first. The condition of the
retaining walls around the pond should also be inspected. In general, the
walls should be inspected to check for possible undercutting of the walls,
migration of sediment through the walls, bulging of walls, displaced
blocks and any other visible indication that the walls may be leaning or
have been damaged. If there appear to be problems with. the condition of
the walls, a structural Engineer shall be contacted to evaluate the walls.
2.1.3. Drainage areas leading
reasonably clear of trash
pipes.
2.2. Inspection Schedule
ito the wet detention basins shall be kept
and debris that may obstruct the basins or
2.2.1. Monthly, or after each 1" in 24 hour rainfall event, whichever comes
first:
2.2.1.1. Inspect the wet detention basin systems for sediment accumulation,
erosion, trash accumulation, vegetated cover and general
conditions. 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. Remove all accumulated litter and debris from the
stormwater collection basins and grates along development
roadways and perform other repairs as necessary.
2.2.1.2. Inspect the rip-rap dissipator pad below the pond outlet and repair
any displaced rip-rap by replacing or adding NCDOT Class B stone
or larger or by using a concrete slurry to bind smaller stones
together to increase their effective size and weight.
2.2.1.3. Check and clear the orifice of any obstructions such that drawdown
of the temporary pool occurs within 2 to 5 days.
2.2.2. Quarterly
2.2.2.1. Thoroughly inspect the stormwater collection system for proper
functioning. Clear accumulated sediment and trash from basin
grates and inverts, and check piping for obstructions.
2.2.2.2. Conduct a thorough visual inspection of outlet structure for the wet
detention basins. Confirm that water surface is being regulated to
elevation 267.50 for Wet Detention Basin No. 1 and to elevation
275.00 for Wet Detention Basin No. 2, which is at the invert
(bottom) of the drawdown orifice entrance into the side of the riser
manhole for each basin. Remove any trash that has accumulated
on the trash rack, which sits atop the outlet structure.
Colonial Grand at Wakefield O&M Manual 3 of 10 ~i~si2oo~

2.2.2.3. Check the downstream side slope of the basins for evidence of
water seepage. Warning signs of water seepage may include
unusually green or lush vegetation or unexplained wetness on the
face of the slope. Inspect the outlet pipe to determine if seepage
occurring around the outside of the pipe.
2.2.2.4. Repair any broken pipes, grates, curb inlets, etc.
2.2.2.5. Riprap pads sha11 be inspected for accumulation of sediment,
weeds and other foreign matter. Remove any sediment, weeds,
and other foreign matter from riprap.
2.2.2.6. Perform a visual inspection of the retaining walls. Check for
bulging due to hydrostatic pressure, exposed toe of walls or
undercutting of walls, bleeding of sediment through walls and check
the overall condition of the walls.
2.2.2.7. Perform all required maintenance for the Monthly inspection.
2.2.3. Semi-Annually
2.2.3.1. Inspect the wet detention basins to determine the amount of
sediment accumulation. If sediment has accumulated to elevation
266.10 for Wet Detention Basin No. 1, or to 273.60 for Wet
Detention Basin No. 2, sediment cleanout is required. This
elevation is 75% of the original design depth for the basins. If
visual inspection determines that sediment, at any location within
the basins, has accumulated to the elevations previously noted, the
basins should be drained and sediment cleaned out. The bottom of
the ponds should be returned to the original design depth as shown
on the drawings entitled "Colonial Grand at Wakefield Apartments",
as approved by the City of Raleigh. If the basins 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.
2.2.3.2. Remove cattails and other indigenous wetland plants when they
cover 50% of the basin surface. These plants should be
encouraged to grow along the vegetated shelf and forebay berm.
2.2.3.3. Perform all required maintenance for the Quarterly inspection.
2.2.4. Annually
2.2.4.1. The Stormwater Drainage System shall be thoroughly inspected
once a year by a North Carolina Registered Professional Engineer,
Registered Landscape Architect or Registered Professional Land
Colonial Grand at Wakefield O&M Manual 4 of 10 ~nsi2oo~

Surveyor. This inspection is required by the City of Raleigh, and is
due on the anniversary of the issuance of the Certificate of
Occupancy. A copy of the annual inspection and maintenance
records shall be submitted to the City of Raleigh Inspections
Department in accordance with the City of Raleigh Code Section
10-9028.
2.2.4.2. Perform all required maintenance for the Semi-Annual inspection.
3. OPERATIONS AND RECORD KEEPING
3.1. The Owner shall maintain a record file including all inspections with a record
of the date, items inspected, and who performed the inspection. A record of
any items that were recommended for repair and subsequently repaired shall
also be included in this file along with the date and who completed the repair.
3.2. During each inspection of the stormwater control measures, the attached
checklist shall be completed and filed with the maintenance records for the
measures.
3.3. The North Carolina Registered Professional Engineer, Registered Landscape
Architect or Registered Professional Land Surveyor who performs the annual
inspection shall complete the attached maintenance record and complete and
seal the attached certification statement. The maintenance record and
certification statement shall be kept in the record file by the Owner, and shall
be submitted to the City of Raleigh Inspections Department in accordance
with Code Section 10-9028.
4. MAJOR REPAIRS
The cost of construction for Wet Detention Basin No. 1 is estimated to be
$134,411.25 and the estimated cost for Wet Detention Basin No. 2 is $108,762.00.
According to the stormwater replacement agreement and RCC Section 10-9027(c)
(2), the Owner is eligible to re-obtain its replacement monies when repair costs
exceed one-third of the initial construction cost, or $44,803.75 for Wet Detention
Basin No. 1 and $36,254.00 for Wet Detention Basin No. 2. Any repair whose cost
exceeds one third of the initial construction cost is considered a Major Repair and is
covered under the stormwater replacement agreement and RCC Section 10-9027(c)
(2). Major repairs would likely be necessary upon discovery of items such as
seepage cracks in the dam slopes, material sliding on side slope face, settlement of
the slopes, or major repair/replacement of outlet structure.
5. PROPOSED ANNUAL BUDGET (PER BASIN)
(No adjustment for Inflation)
Colonial Grand at Wakefield O&M Manual 5 of 10 ~i~ai2oo~

Wet Detention Basin No. 1 and Basin No. 2:
Item Annual Costs Annual Costs Total Annual Costs
Basin No. 1 Basin No. 2 Basin Nos. 1 and 2
(1) Maint. Cost for Mowing, Seeding, $8,000.00 $8,000.00 $16,000.00
Fertilizin and Trash Removal
(2) Liability Insurance and Property $1,000.00 $1,000.00 $2,000.00
Insurance Premiums
(3) Annual Inspection by Professionals $3,000.00 $3,000.00 $6,000.00
(4) Sediment Removal (every 5 years) $2,000.00 $2,000.00 $4,000.00
Annualized Cost
(5) Rip-Rap Replacement (every 3 years) $1,000.00 $1,000.00 $2,000.00
Annualized Cost
(6) Payment of Stormwater Replacement $2,025.14 $1,605.99 $3,631.13
Contribution to Cit of Ralei h '`
Total Annual Budget $17,025.14 $16,605.99 $33,631.13
'` The payment for stormwater replacement contribution to the City of Raleigh noted above are based
on the replacement cost payment schedule for years 2-5.
6. REPLACEMENT COST CONTRIBUTIONS TO THE CITY OF RALEIGH
Wet Detention Basin No. 1:
Engineered Stormwater Control
Measures Quantity Estimated Unit
Price Estimated cost
Dam embankment 460 CY $8.00 / CY $3,680.00
Pond outlet structure 1 EA $12,500.00 / EA $12,500.00
Seeding and Mulching 1.0 AC $1,600.00/AC $1,600.00
Total Basin No. 1 $17,780.00
Wet Detention Basin No. 2:
Engineered Stormwater
Control Measures Quantity Estimated Unit
Price Estimated cost
Pond outlet structure 1 EA $12,500.00 / EA $12,500.00
Seeding and Mulching 1.0 AC $1,600.00/AC $1,600.00
Total Basin No. 2 $14,100.00
Summary of Total Replacement Costs for Wet Detention Basin Nos. 1 and 2:
Colonial Grand at Wakefield O&M Manual 6 of 10 ~i~si2oo~

Wet Detention Basin No. 1 $ 17,780.00
Wet Detention Basin No. 2 $ 14,100.00
Total Replacement Cost $ 31,880.00
Replacement cost payment schedule:
Year Number Contribution Payment* Formula used to Derive Payments
1 $ 8,413.13 ($31,880.00*0.15)+($31,880.00*0.85*0.67)/5
2 $ 3,631.13 ($31,880.00*0.85*0.67)/5
3 $ 3,631.13 ($31,880.00*0.85*0.67)/5
4 $ 3,631.13 ($31,880.00*0.85*0.67)/5
5 $ 3,631.13 ($31,880.00*0.85*0.67)/5
6 $ 1,788.47 ($31,880.00*0.85*0.33)/5
7 $ 1,788.47 ($31,880.00*0.85*0.33)/5
8 $ 1,788.47 ($31,880.00*0.85*0.33)/5
9 $ 1,788.47 ($31,880.00*0.85*0.33)/5
10 $ 1,788.47 ($31,880.00*0.85*0.33)/5
'`Payments to the City of Raleigh are due on July 1St of each Year.
Prepared by: Bass, Nixon 8~ Kennedy, Inc.
6310 Chapel Hill Rd., Suite 250
Raleigh, North Carolina 27607
Dated: July 16~', 2007
Colonial Grand at Wakefield O&M Manual 7 of 10 ~n8i2oo~

Date:
Inspector(s):
Time:
Inspection: Monthly Quarterly Semi-Annual Annual
Retention Pond
w
m ~ `~
,~
d
Observations (condition, Deficiencies, ~
`~ ~ S
~
m
j Items Ins ected etc. ~ ~ ~
Erosion on side slo es or other
Prima s illwa /culvert
Bare or denuded areas
eeds /wood ve etation
e etative hei ht
Sediment accumulation
See a e /wetness
Retainin walls
Other
General Comments, Sketches ~ Field Measurements
Add Additional Sheets if Needed
Colonial Grand at Wakefield O&M Manual 8 of 10 ~i~si2oo~

For Annual Inspection Report, Submit to City of Raleigh
certify that the storm water management facilities and open space areas referenced in
this document have been maintained in conformance with the approved storm water
management plan and maintenance manual. This certification is made based on
personal observation of the site and review of the maintenance records.
Signed
(seal)
Date:
Note:
Must be signed, sealed and dated by a North Carolina Registered Professional
Engineer, Registered Landscape Architect or Profession Land Surveyor.
Colonial Grand at Wakefield O&M Manual 9 of 10 ~i~si2oo~

Seeding Schedule
Shoulders, Side Ditches, Slopes (Max 3:1)
DATE
TYPE
PLANTING RATE
3001bs/acre
3001bs/acre
3001bs/acre
251bs/acre
1251bs/acre
351bs/acre
301bs/acre
Aug 15 -Nov
1Nov 1-Mar
1Mar1-Apr
15Apr 15 -Jun
30Ju1 1-Aug 15
Tall Fescue
Tall Fescue & Abruzzi Rye
Tall Fescue
Hulled Common Bermudagrass
Tall Fescue and
*** Browntop Millet or
*** Sorghum-Sudan Hybrids
Slopes (3:1 to 2:1)
Mar 1-Jun 1 Sericea Lespedeza (scarified) &
(Marl -Apr 15) Add Tall Fescue
(Mar 1-Jun 30) or Add Weeping Love grass
(Mar 1-Jun 30) Or Add Hulled Common Bermudagrass
Jun 1-Sept 1 Tall Fescue and
*** Browntop Mullet or
*** Sorghum-Sudan Hybrids
Sept 1-Mar 1 Sericea Lespedeza (unhulled - unscarified)
And Tall Fescue
(Nov 1-Mar 1) And Abruzzi Rye
501bs/acre
1201bs/acre
10 lbs/acre
251bs/acre
1201bs/acre
351bs/acre
301bs/acre
701bs/acre
1201bs/acre
251bs/acre
Consult EFS Environmental Engineer for additional information concerning other alternatives for vegetation
of denuded areas. The above vegetation rates are those which do well under local conditions; other seeding
rate combinations are possible.
*** TEMPORARY :Reseed according to optimum season for desired permanent vegetation. Do not allow temporary
cover to grow over 12" in height before mowing, otherwise fescue may be shaded out.
Colonial Grand at Wakefield O&M Manual 10 of 10 ~i~si2oo~

BASS, NIXON & KENNEDY, INC., CONSULTING ENGINEERS
6310 CHAPEL HILL ROAD, SUITE 250, RALEIGH, NC 27607
919/851-4422 ^ FAX [phone]
COLONIAL GRAND AT WAKEFIELD
APARTMENTS
RALEIGH, NORTH CAROLINA

1
DWQ SUBMITTAL CALCULATIONS
DESIGN CALCULATIONS
FOR WET DETENTION BASIN
NOS. 1 AND 2
FOR 85% TSS REMOVAL AND
PRE/POST-DEVELOPMENT
STORMWATER ATTENUATION
so
!~rcCStn,

7J~d 1 a'~
PREPARED BY
BASS, NIXON AND KENNEDY, INC.
JULY 14, 2007

1
' BASS, NIXON & KENNEDY, INC., CONSULTING ENGINEERS
~ 6310 CHAPEL HILL ROAD, SUITE 250, RALEIGH, NC 27607
' ~ 919/851-4422 ^ FAX [phone]
' COLONIAL GRAND AT WAKEFIELD
APARTMENTS
' RALEIGH, NORTH CAROLINA
WET DETENTION BASINS
' DESIGN CALCULATIONS
FOR DWQ SUBMITTAL
July 14, 2007
The following calculations are for the design of the wet detention basins for the Colonial
' Grand at Wakefield Apartments in Raleigh, North Carolina. The wet detention basins
are designed as stormwater BMP's for 85% TSS removal as required by the N.C.
Division of Water Quality (NCDWQ) as well as to provide stormwater attenuation for the
' 2-year and 10-year, 24-hour storms as required by the City of Raleigh. The stormwater
Best Management Practices dated April, 1999 by NCDENR (Section 1.0 -Wet
Detention Basins) and the City of Raleigh stormwater Management Design Manual
' dated January, 2002 were used for design of the wet detention basins.
The Colonial Grand at Wakefield Apartments is located in the Wakefield Development
site in Raleigh, North Carolina. There are no stream buffer impacts or stream crossings
proposed as part of the Colonial Grand at Wakefield Apartments project. In the
approval letter issued by the NCDWQ dated May 4, 1999 (DWQ Project #970694), the
' NCDWQ noted an additional condition that a final written stormwater plan which meets
85% TSS removal is required for development within the Wakefield Development.
Based on the requirements of the May 4, 1999 approval letter and discussions with
' Annette Lucas of the NCDWQ, two wet detention basins are proposed for the site: wet
detention basin No. 1 is located on the south side of the site and wet detention basin
No. 2 is located on the north side of the site. The basins are designed to provide 85%
' TSS removal as well as for stormwater attenuation for the 2-year and 10-year, 24-hour
storms. The following summarizes design information for the two basins:
' Wet Detention Basin No. 1
' The following summarizes the design calculations for wet detention basin No. 1 to
provide 85% TSS removal as well as stormwater attenuation so that the site Q2 and
Q10pnst-development discharge does not exceed the pre-development discharge:
• Determine Surface Area Required for Permanent Pool
' Drainage Area 6.9 acres
Impervious Area 4.3 acres
' Colonial Grand -stormwater Calcs. 7/14/2007

Percent Impervious = 62.3%
Set Permanent Pool Level at 267.50 Feet,
See Appendix A for the water quality pond design information using
excel spreadsheet.
• Summary of Design for Wet Detention Basin No. 1
The wet detention basin will need to provide stormwater attenuation so that the
post-development runoff for the 2-year and 10-year, 24-hour storms does not
exceed the pre-development runoff. Set the top of the riser above the temporary
pool elevation to provide additional storage for stormwater detention:
Top of Basin Embankment
Set Top of Emergency Spillway
Set Top of Riser
Set Temporary Pool
Set Invert of 2" Dia. Drawdown
Pipe (Perm. Pool)
Set Basin Invert
= 271.00 Ft.
= 269.60 Ft.
= 269.20 Ft.
= 268.32 Ft. +/-
= 267.50 Ft.
= 262.00 Ft.
• Calculate the Q2/Q10 Pre- and Post-Developed Discharge
The following summarizes the pre- and post-developed Q2 and Q10 discharge for
the area draining to water quality basin No. 1:
Drainage Area = 6.9 Acres
Pre-Dev. Composite C = 0.20
Post-Dev. Composite C = 0.70
Intensity (2-year) = 5.76 In/Hr
Intensity (10-year) = 7.22 In/Hr
Intensity (100-year) = 9.72 In/Hr
Use the Rational Equation to calculate the Q2, Q10 and Q100 pre- and post-
developed discharge for the area draining to water quality basin No. 1:
Pre-Developed Discharge
Q2 = 7.9 cfs
Q10 = 10.0 cfs
Q100 = 13.4 cfs
Post-Developed Discharge
Q2 = 27.8 cfs
Q 10 = 34.9 cfs
Q 100 = 46.9 cfs
Colonial Grand -stormwater Calcs. 2 7/14/2007

'
Minimum Attenuation Required
Q2 = 19.9 cfs
' Q10 = 24.9 cfs
• Summary of Stormwater Routing Calculations:
' Q2 Discharge into Basin = 27.8 CFS
Q2 Discharge out of Basin = 4.5 CFS < 7.9 CFS Okay
' Q10 Dischar a into Basin =
9 34.9 CFS
Q10 Discharge out of Basin = 8.4 CFS < 10.0 CFS Okay
'
Q2 Waterlevel = 269.41 Feet
' Q10 Waterlevel _
Q100 Waterlevel 269.56 Feet
269.79 Feet
Top of Dam = 271.00 Feet
' See Appendix B for Wet Detention Basin No. 1 routing calculations
using PondPack computer software by Haestad Methods.

' Wet Detention Basin No. 2
The following summarizes the design calculations for wet detention basin No. 2 to
' provide 85% TSS removal as well as stormwater attenuation so that the site Q2 and
Q10 post-development discharge does not exceed the pre-development discharge:
' Determine Surface Area Required for Permanent Pool
Drainage Area = 11.3 acres
' Impervious Area = 6.9 acres
Percent Impervious = 61.1
' Set Permanent Pool Level at 275.00 Feet,
' See Appendix C for the water quality pond design information using
excel spreadsheet.
Summa of Desi n for Water Qualit Basin No. 2
• ry 9 Y
' The wet detention basin will need to provide stormwater attenuation so that the
post-development runoff for the 2-year and 10-year, 24-hour storms does not
' exceed the pre-development runoff. Set the top of the riser above the temporary
pool elevation to provide additional storage for stormwater detention:
' Colonial Grand -Stormwater Calcs. 3 7/14/2007

Top of Basin Embankment = 282.00 Ft.
Set Top of Riser = 279.50 Ft.
Set Temporary Pool = 276.44 Ft. +/-
Set Invert of 2.5" Dia. Drawdown
Pipe (Perm. Pool) = 275.00 Ft.
Set Basin Invert = 269.50 Ft.
• Calculate the Q2/Q10 Pre- and Post-Developed Discharge
The following summarizes the pre- and post-developed Q2 and Q10 discharge for
the area draining to water quality basin No. 2:
Drainage Area = 11.3 Acres
Pre-Dev. Composite C = 0.20
Post-Dev. Composite C = 0.70
Intensity (2-year) = 5.76 In/Hr
Intensity (10-year) = 7.22 In/Hr
Intensity (100-year) = 9.72 In/Hr
Use the Rational Equation to calculate the Q2 and Q10 pre- and post-developed
discharge for the area draining to water qu ality basin No. 2:
Pre-Developed Discharge
Q2 = 13.0 cfs
Q10 = 16.3 cfs
Q100 = 22.0 cfs
Post-Developed Discharge
Q2 = 45.6 cfs
Q10 = 57.1 cfs
Q100 = 76.9 cfs
Minimum Attenuation Required
Q2 = 32.6 cfs
Q10 = 40.8 cfs
• Summary of Stormwater Routing Calculations:
Q2 Discharge into Basin = 45.6 CFS
Q2 Discharge out of Basin = 0.7 CFS < 13.0 CFS Okay
Q10 Discharge into Basin = 57.1 CFS
Q10 Discharge out of Basin = 2.3 CFS < 16.3 CFS Okay
Q2 Waterlevel = 279.51 Feet
Q10 Waterievel = 279.57 Feet
Q100 Waterlevel = 279.80 Feet
Colonial Grand -Stormwater Calcs. 4 7/14/2007

' Top of Dam = 282.00 Feet
See Appendix D for Wet Detention Basin No. 2 routing calculations
using PondPack computer software by Haestad Methods.
t Summary of Overall Site Q2/Q10 Pre- and Post-Developed Discharge
• Calculate the Q2 and Q10 pre- and post-developed discharge for the overall site.
' The following summarizes the pre- and post-developed Q2 and Q10 discharge for
the overall site:
' Overall Site Area = 26.5 Acres
Pre-Dev. Composite C = 0.20
Post-Dev. Composite C _ 0.60 (for overall site)
' Intensity (2-year) 5.76 In/Hr
Intensity (10-year) = 7.22 In/Hr
' Use the Rational Equation to calculate the Q2 and Q10 pre- and post-developed
discharge for the overall site:
Pre-Developed Discharge
Q2 = 30.5 cfs
' Q10 = 38.3 cfs
Post-Developed Discharge without Stormwater Attenuation
Q2 = 91.6 cfs
Q 10 = 114.8 cfs
' Attenuation Required
Q2 61.1 cfs
Q 10 = 76.5 cfs
r
• Summarize the Q2 and Q10 attenuation provided by Water Quality Basin Nos. 1 and
' 2 from the above information and attached routing calculations:
Water Quality Basin No. 1
Q2 Inflow = 27.8 cfs
Q2 Outflow = 4.5 cfs
' Attenuation Provided for 2-Year Storm = 23.3 cfs
' Q10 Inflow _ 34.9 cfs
Q10 Outflow 8.4 cfs
Attenuation Provided for 10-Year Storm = 26.5 cfs
r
Water Quality Basin No. 2
' Colonial Grand -Stormwater Calcs. 5 7/14/2007

Q2 Inflow = 45.6 cfs
Q2 Outflow = 0.7 cfs
Attenuation Provided for 2-Year Storm = 44.9 cfs
Q10 Inflow = 57.1 cfs
Q10 Outflow = 2.3 cfs
Attenuation Provided for 10-Year Storm = 54.8 cfs
Total Q2 Attenuation Provided =
Minimum Q2 Attenuation Req'd =
Total Q10 Attenuation Provided =
Minimum Q10 Attenuation Req'd =
23.3 cfs + 44.9 cfs
68.2 cfs
61.1 cfs < 68.2 cfs Okay
26.6 cfs + 54.8 cfs
81.4 cfs
76.5 cfs < 81.4 cfs Okay
Colonial Grand - Stormwater Calcs. ~ 6 7/14/2007

Project No. DWQ (to be provided by DWQ

1
n

DIVISION OF WATER QUALITY - 401 WET DETENTION BASIN WORKSHEET
DWQ Stormwater Management Plan Review:
A complete stormwater management plan submittal includes a wet detention basin worksheet for each basin,
design calculations, plans and specifications showing all basin and outlet structure details, and a fully executed
operation and maintenance agreement. An incomplete submittal package will result in a request for additional
information and will substantially delay final review and approval of the project.
I. PROJECT INFORMATION (please complete the following information):
Project Name : Colonial Grand at Wakefield
Contact Person: David L. Dunn~PE Phone Number: [phone]
For projects with multiple basins, specify which basin this worksheet applies to: Basin No. 1
Basin Bottom Elevation
Permanent Pool Elevation
Temporary Pool Elevation
261.50 ft.
267.50 ft.
268.32 ft.
(average elevation of the floor of the basin)
(elevation of the orifice invert out)
(elevation of the outlet structure invert in)
Permanent Pool Surface Area
Drainage Area
Impervious Area
17,492 sq. ft.
6.9 ac.
4.3 ac.
(water surface area at permanent pool elevation)
(on-site and off.-site drainage to the basin)
(on-site and off-site drainage to the basin)
' Permanent Pool Volume 53,953 cu. ft. (combined volume of main basin and forebay)
Temporary Pool Volume 15,300 cu. ft. (volume detained on top of the permanent pool)
Forebay Volume 11,282 cu. ft.
'
SA/DA used 2.51 (surface area to drainage area ratio)
Diameter of Orifice 2.0 in. (draw down orifice diameter)
' II. REQUIRED ITEMS CHECKLIST
The following che cklist outlines design requirements per the Stormwater Best Management Practices manual
(N.C. Department of Environment, Health and Natural Resources, November 1995) and Administrative Code
Section: 15 A NCAC 2H .1008. Initial in the space provided to indicate the following design requirements have
been met and supporting documentation is attached. If a requirement has not been met, attach an explanatio» of
why.
' Applicants Initials
~~~ The temporary pool controls runoff from the 1 inch storm event.
' ~La
~ ~ The basin length to width ratio is greater than 3:1. ~
The basin side slopes are no steeper than 3:1.
~~~ A submerged and vegetated perimeter shelf at less than 6:1 is provided.
' ~'a
•~~-~ Vegetation to the permanent pool elevation is specified.
An emergency drain is provided to drain the basin.
~L~ The permanent pool depth is between 3 and 6 feet (required minimum of 3 feet).
~4~ The temporary pool draws down in 2 to 5 days.
' ~+-~ The forebay volume is approximately equal to 20% of the total basin volume.
Ji-~ Sediment storage is provided in the permanent pool.
~L~ Access is provided for maintenance.
' .y/~. ~+~ A minimum 30-foot vegetative filter is provided at the outlet.
~~~ A site specific operation and maintenance (O&M) plan is provided.
> ~ ~ A vegetation management/mowing schedule is provided in the O&M plan.
' ~~~ Semi-annual inspections are specified in the O&M plan.
~ 4~ A debris check is specified in the O&M plan to be performed after every storm event.
>~~ A specific sediment clean-out benchmark is listed (elevation or depth) in O&M plan.
' ~'-~ A responsible party is designated in the O&M plan.
FORM SWG100 09/97 Page 1 of 1

Project No. DWQ (to be provided by DWQf
DIVISION OF WATER QUALITY - 401 WET DETENTION BASIN WORKSHEET
DWQ Stormwater Management Plan Review:
A complete stormwater management plan submittal includes a wet detention basin worksheet for each basin,
design calculations, plans and specifications showing all basin and outlet structure details, and a fully executed
operation and maintenance agreement. An incomplete submittal package will result in a request for additional
information and will substantially delay final review and approval of the project.
I. PROJECT INFORMATION (please complete the following information):
Project Name : Colonial Grand at Wakefield
Contact Person: David L. Dunn, PE Phone Number: [phone]
For projects with multiple basins, specify which basin this worksheet applies to: Basin No. 2
Basin Bottom Elevation
Permanent Pool Elevation
Temporary Pool Elevation
Permanent Pool Surface Area
' Drainage Area
Impervious Area

1

1

Permanent Pool Volume
Temporary Pool Volume
Forebay Volume
SA/DA used
Diameter of Orifice
269.50 ft.
275.00 ft.
276.44 ft.
15,821 sq. ft.
11.3 ac.
6.9 ac.
47,665 cu. ft.
24,593 cu. ft.
10,629 cu. ft.
2.45
2.5 in.
(average elevation of the floor of the basin)
(elevation of the orifice invert out)
(elevation of the outlet structure invert in)
(water surface area at permanent pool elevation)
(on-site and off-site drainage to the basin)
(on-site and off-site drainage to the basin)
(combined volume of main basin and forebay)
(volume detained on top of the permanent pool)
(surface area to drainage area ratio)
(draw down orifice diameter)
IL REQUIRED ITEMS CHECKLIST
The following checklist outlines design requirements per the Stormwater Best Management Practices manual
(N.C. Department of Enviromnent, Health and Natural Resources, November 1995) and Administrative Code
Section: 15 A NCAC 2H .1008. Initial in the space provided to indicate the following design requirements have
been met and supporting documentation is attached. If a requirement has not been »zet, attach an explanation of
why.
Annlicants Initials
~w~ The temporary pool controls runoff from the 1 inch storm event.
~ Z~ The basin length to width ratio is greater than 3:1.'"
~ L7 The basin side slopes are no steeper than 3:1.
i~L~ A submerged and vegetated perimeter shelf at less than 6:1 is provided.
+~.~ Vegetation to the permanent pool elevation is specified.
~~~ An emergency drain is provided to drain the basin.
~~~ The permanent pool depth is between 3 and 6 feet (required minimum of 3 feet).
~~~ The temporary pool draws down in 2 to 5 days.
~~ The forebay volume is approximately equal to 20% of the total basin volume.
.~`~ Sediment storage is provided in the permanent pool.
>~ Access is provided for maintenance.
.y/n ~~ A minimum 30-foot vegetative filter is provided at the outlet.
,~c.~ A site specific operation and maintenance (O&M) plan is provided.
>~ ~ A vegetation management/mowing schedule is provided in the O&M plan.
~~ Semi-annual inspections are specified in the O&M plan.
~ i~ A debris check is specified in the O&M plan to be performed after every storm event.
.a ~.~ A specific sediment clean-out benchmark is listed (elevation or depth) in O&M plan.
~ ~ A responsible party is designated in the O&M plan.
FORM SWG100 09/97 Page 1 of 1

ii
APPENDIX A -
' SUMMARY OF WATER
QUALITY BASIN DESIGN
' CALCULATIONS FOR WET
DETENTION BASIN NO. 1
USING EXCEL SPREADSHEET
' Colonial Grand - Stormwater Calcs. 7 7/14/2007

' Water Quali Retention Calculations
ty
Project Name: Colonial Grand at Wakefield -Wet Detention Basin No. 1
' Date: July 14, 2007
Determine Surface Area Required for Permanent Pool:
' Drainage Area (ac): 6.9
Impervious Area (ac): 4.3
Percent Impervious: 62.3%
' Perm. Pool Depth (ft): 3
SA/DA @ 60% 2.4 (from Table 1.1 of NCDENR's Stormwater BMP manual)
SA/DA @ 70% 2.88 (from Table 1.1 of NCDENR's Stormwater BMP manual)
' Interpolated SA/DA: 2.51
Req. Surface Area (sf): 7,548 (at permanent pool elevation)
' Perm. Pool Elevation: 267.50
Provided Surface Area (sf): 17,492 OK -Surface area requirement met
Provided Storage (cf): 53,953
' Check Hydraulic Depth (ft): 3.08 OK -Hydraulic depth requirement met
Calculate the Volume Required to Treat the First Flush:
' Rainfall to Treat: 1 inch(es)
Runoff Coefficient (Rv) = 0.05 + 0.009`(% Impervious)
Runoff Coefficient (Rv): 0.61 in/in
' Runoff Volume (V) =Rainfall ` (Rv) ` (Drainage Area)
Runoff Volume (V): 15,300 CF
' Calculate the Depth Required for the Temaorarv Pool:
Perm. Pool Elevation: 267.50
Provided Surface Area (sf): 17,492 (at permanent pool elevation)
t Provided Storage (cf): 53,953
Volume Req. for Temp. Pool (CF): 15,300 (this amount required above Perm. Pool)
Total Volume Req Temp & Perm(CF): 69,253
' EI. Of Temp. Pool Between: 268.00 and 269.00
EI. Of Temp. Pool: 268.32
Depth of Temp. Pool (ft): 0.82 measured from perm. Pool elevation
' Determine the Orifice Size for 2-5 Dav Drawdown:
Orifice Invert Elevation: 267.50
Elevation of Temp. Pool: 268.32
' Or~ce Diameter (in): 2.00
Use the orifice equation to determine flow and drawdown time:
Orrfice Equation: Q = C ` A ` (2gh)^0.5
Volume to Draw Down (CF): 15,300
Flow for 2-Day Drawdown (CFS): 0.089
Flow for 5-Day Drawdown (CFS): 0.035
C: 0.6
' g (SF/s): 32.2
h (ft): 0.368 (average driving head to centerline of orifice)
A (sf): 0.0218
' Solve Orifice Equation for Q (CFS): 0.064
Drawdown Time (Days): 2.78 OK -Drawdown between 2 and 5 days.

[1

1

J

C
o~
' E

U
C
' c
O
m
~ W
Q ~ O
r O
CI' O
i` O
r ti
Ln M
L() O
t1') 'd'
O 00
M I`
0 O
0 O
0 O
0 O
0
a s r r r N N M ~ "d; ~ L!~ 0 0 0 0
`-~ 0 0 0 0 0 0 0 0 0 0 0 0 0 0
W
Q N O r N M Ct tn tO r~ 00 0 ~ ~ ~ ~
I-
N

W
O
~
~
O
O
~
O
O
O .a
O 'O
O .a
O O
O

V~ ^
M
<
F-
V~
O ~
'~
cN
ti tl
j
~
~O
~
l~ N
N
f~ t!')
M
~
O
~
O
'C
O
~
O
'C
Q J
O ~L O
Op O to O N O
N N ~ O O O N N
... ~ r N M ~ (
D ~ O
r M
r >
O >
O >
O >
Q
W 0 0 0 0 0 0 0 0 0
'~
M I.[) O O ~ ~
N ~ In O
N O
M
0
0
0
0
~ < O d- o0 0 N
d' O r
O r
Ln ti r 0 0 0 0
O V'
v O
~ r O
O O M ti O N ~ 0 0 0 0
~ ~ r r r N N N
~ ° ° ~ ~ ~ ° °
Q ... ° o o
N "
N
r "
~
N o,
M o o o o
W ~- 0 ~ 00 0 ~ 0 0 ~ ^ 0 0 0 0
W Q N O N ~ M N Ct i.n d' I~ 0 0 0 0
~
Q ~ ^ ~ O
~ M
~ I~
r O
N N
N Ct
N
Q N N l~ d~ r M
07 N
~ ~
O N
r N
M ~
O
W < ct Cfl 00 d7 r- M t.f) ~ d' O)
~
Q H
LL
v ~
LA ~
C4 I~
i~ ~
~ r
r LA
r ~
r r
N M
N tf')
N
0 0 0 0 0 0 0 0 0 0 0 0 0
O 0
O
W O O O O O O O O O O O O
J N M ~ 11') (D I~ OO ai O ~ N M C1' ll'i
W CD
N CO
N CO
N CO
N CO
N CO
N CO
N CO
N 1~
N 1~
N 1~
N 1~
N I~
N I~
N

...
C
(0
O
a
0
O
c
' ~N
fA
O
O
a
' c
C
(6
N
4.
O C
' ~ O
N ~
Q 'a
' ~, a~
rn~
~_ ~
fQ ~.,
~ U
C
' O ~
"'' ~U
(C
~ W
~ ~
U O
t6
~ ~
r
.a
co
H

0
~ o o ~ o 0 0 ~ ~ o
~ o 0 0 0 0 0 0 0 0
~ N M ~ l1') C~ 1~ O O
\°
0

~ CO
N d'
~ N
CC f~
I~ N
O O
~ CO
N N
d' f~
O
O O O O O O ~ r- ~ ~

O O cfl ~t N O oO tA O M
N ~ CC oD O ~- M Cfl op
0 0 0 0 0 ~ ~ ~ ~ ~-
~ o ~
M .-
In o
ti o
O rn
O a
N »
~ cc
M ~
.-
y
"" ~ 0 0 0 0 ~ ~- ~ ~ N
t

D

O
O tn
M O
B M
o~ ll~
O O
M ~
B O
t~ O
~ d'
M
D
a 0 0 0 0 ~ r' ~ ~ N N
C

C
t~
E
~ O M
tt O
I~ 1~
O Lf~
N O
t0 ~-
~ 1~
O 00
M CC
CO
d ~ 0 0 0 ~ ~- N N N

O O 01 00 M M M O op O
d' ~ O '~ ~ O ~ ti ~
X 0 0 ~- ~ ~ N N N M

O a~ f~ d' M cc o 0o cc v
In C7 M i~ O ~ Op M 1~
M O O ~ ~ N N N M M
7
O
o ~ 0 0 0 0 0 0 0
X 0 0 0 0 0 0 0 0 0
~ N M ~ lf~ Cfl t~ 00 O
0
c
0
W
O
O
O
U
O

1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
APPENDIX B -
SUMMARY OF ROUTING
CALCULATIONS FOR WET
DETENTION BASIN NO. 1
FOR THE Q2, Q10 AND Q100
STORMS USING PONDPACK
COMPUTER SOFTWARE BY
HAESTAD METHODS
Colonial Grand - Stormwater Calcs. 8
7/14/2007

Job Fite: R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD
APARTMENTS - WET DETENTION BASIN 1 (Q2 ANALYSIS - 7-14-07).PPW
Rain Dir: C:\HAESTAD\PPKW\RAINFALL\
--------------------------
--------------------------
JOB TITLE
--------------------------
--------------------------
COLONIAL GRAND AT WAKEFIELD APARTMENTS
WET DETENTION BASIN N0. 1
Q2 ROUTING CALCULATIONS
The following calculations are the routing calculations for the
Colonial Grand at Wakefield Apartments in Raleigh, North Carolina.
Wet Detention Basin Nos. 1 and 2 are designed to provide 85% TSS
removal as required by the NCDWQ and also to reduce the Q2 and Q10
post-developed discharge to less than or equal to the Q2 and Q10
pre-developed discharge for each point of discharge as required by
the City of Raleigh. The basins are also designed to pass the
Q100 storm without overtopping the dam. The site stormwater
calculations were performed using the Rational Method. The
attached routing calculations were performed using the SCS
methodology. The SCS curve number was manipulated so that the
discharge for the respective storm will equal the discharge based
on the Rational Equation.
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:20:04 Date: 07/14/2007

Table of Contents
i
Table of Contents
***:****************** MASTER SUMMARY **********************
Watershed....... Master Network Summary ............. 1.01
****************** DESIGN STORMS SUMMARY *******************
Raleigh......... Design Storms ...................... 2.01
******************** RUNOFF HYDROGRAPHS ********************
BASIN D.A...... 2-Year
SCS Unit Hyd. Summary .............. 3.01
*********************** POND VOLUMES ******s****************
POND 1.......... Vol: Elev-Area ..................... 4.01
******************** OUTLET STRUCTURES *********************
OUTLET.......... Outlet Input Data .................. 5.01
Composite Rating Curve ............. 5.05
***********:*******sss* POND ROUTING *:*********************
POND 1 OUT 2-Year
Pond Routing Summary ............... 6.01
5/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:20:04 Date: 07/14/2007

Type.... Master Network Summary Page 1.01
Name.... Watershed
File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 1 (Q2 ANALYSIS - 7-14-07).PPW
MASTER DESIGN STORM SUMMARY
Default Network Design Storm File, ID STORMS.RNQ Raleigh
Total
Depth Rainfall
Return Event in Type RNF Fite RNF ID
------------ ------ ---------------- -------- ----------------
Z-Year 3.6000 Synthetic Curve SCSTYPES TypeII 24hr
MASTER NETWORK SUMMARY
SCS Unit Hydrograph Method
(*Node=Outfalt; +Node=Diversion;)
(Trun= HYG Truncation: Blank=None; L=Left; R=Rt; LR=Left&Rt)
Return HYG Vol
Storage
Node ID
----------------- Type
---- Event
------ ac-ft Trun
---------- --
BASIN D.A. AREA 2 1.571
*DISCHARGE PT 1 JCT 2 1.425
POND 1 IN POND 2 1.571
POND 1 OUT POND 2 1.425
2.104
Max
Qpeak Qpeak Max WSEL Pond
hrs
--------- cfs ft ac-ft
-------- -------- ---------
11.9000 27.81
12.1500 4.48
11.9000 27.81
12.1500 4.48 269.41
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:20:04 Date: 07/14/2007

Type.... Design Storms
Name.... Raleigh
File.... C:\HAESTAD\PPKW\RAINFALL\STORMS.RNQ
Title... COLONIAL GRAND AT WAKEFIELD APARTMENTS
WET DETENTION BASIN N0. 1
Q2 ROUTING CALCULATIONS
The following calculations are the routing
calculations for the Colonial Grand at Wakefield
Apartments in Raleigh, North Carolina. Wet Detention
Basin Nos. 1 and 2 are designed to provide 85% TSS
removal as required by the NCDWQ and also to reduce
the Q2 and Q10 post-developed discharge to less than
or equal to the Q2 and Q10 pre-developed discharge
for each point of discharge as required by the City
of Raleigh. The basins are also designed to pass the
Q100 storm without overtopping the dam. The site
stormwater calculations were performed using the
Rational Method. The attached routing calculations
were performed using the SCS methodology. The SCS
curve number was manipulated so that the discharge
for the respective storm will equal the discharge
based on the Rational Equation.
DESIGN STORMS SUMMARY
Design Storm File,ID = STORMS.RNQ Raleigh
Storm Tag Name = 2-Year
Page 2.01
Data Type, File, ID = Synthetic Storm SCSTYPES.RNF TypeII 24hr
Storm Frequency = 2 yr
Total Rainfall Depth= 3.6000 in
Duration Multiplier = 1
Resulting Duration = 24.0000 hrs
Resulting Start Time= .0000 hrs Step= .1000 hrs End= 24.0000 hrs
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:20:04 Date: 07/14/2007

Type.... SCS Unit Hyd. Summary Page 3.01
Name.... BASIN D.A. Tag: 2-Year Event: 2 yr
' File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 1 (Q2 ANALYSIS - 7-14-07).PPW
Storm... TypeII 24hr Tag: 2-Year
SCS UNIT HYDROGRAPH METHOD
STORM EVENT: 2 year storm
Duration = 24.0000 hrs Rain Depth = 3.6000 in
' Rain Dir = C:\HAESTAD\PPKW\RAINFALL\
Rain File -ID = SCSTYPES.RNF - TypeII 24hr
Unit Hyd Type = Default Curvilinear
HYG Dir - R~\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL
CALCS\
HYG File ID BASIN D.A. 2-Year
Tc (Min. Tc) _ .0833 hrs
' Drainage Area = 6.900 acres Runoff CN= 92
--------------------------------------------
--------------------------------------------
Computational Time Increment = .01111 hrs
Computed Peak Time 11.9175 hrs
Computed Peak Flow 28.56 cfs
' Time Increment for HYG File = .0500 hrs
Peak Time, Interpolated Output = 11.9000 hrs
Peak Flow, Interpolated Output = 27.81 cfs
--------------------------------------------
--------------------------------------------
DRAINAGE AREA
ID:None Selected
CN = 92
Area = 6.900 acres
5 = .8696 in
0.25 = .1739 in
Cumulative Runoff
-------------------
2.7325 in
1.571 ac-ft
HYG Votume... 1.571 ac-ft (area under HYG curve)
***** UNIT HYDROGRAPH PARAMETERS *****
Time Concentration, Tc = .08330 hrs (ID: None Selected)
Compu tational Incr, Tm = .01111 hrs = 0. 20000 Tp
Unit Hyd. Shape Fact or = 483.432 (37.46% under rising limb)
K = 483.43/645.333, K = .7491 (also, K = 2/(1+(Tr/Tp))
'
Reced ing/Rising, Tr/ Tp = 1.6698 (solved from K = .7491)
Unit peak, qp = 93.85 cfs
'
Unit peak time Tp = .05553 hrs
Unit receding limb, Tr = .22213 hrs
Total
1 unit time, Tb = .27767 hrs
S/N: 621802506A84 Bass Nixon & Kennedy Inc
' PondPack Ver. 7.5 (786c) Compute Time: 10:20:04 Date: 07/14/2007

Type.... Vot: Elev-Area Page 4.01 '
Name.... POND 1
File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS '
- WET DETENTION BASIN 1 (Q2 ANALYSIS - 7-14-07).PPW
Title... Wet Detention Basin No. 1
Elevation Planimeter Area Al+A2+sgr(A1*A2) Volume Volume Sum
(ft)
------------ (sq.in) (acres)
--------------------- (acres)
----------- (ac-ft) (ac-ft)

262.00
----- .1180 ------
.0000 ---------
.000 -------------
.000
264.00 ----- .1788 .4421 .295 .295
266.00 ----- .2577 .6512 .434 .729
268.00 ----- .4498 1.0480 .699 1.427
270.00 ----- .5379 1.4796 .986 2.414
271.00 ----- .5968 1.7013 .567 2.981
POND VOLUME EQUATIONS
* Incremental volume computed by the Conic Method for Reservoir Volumes.
Volume = (1/3) * (EL2-EL1) * (Areal + Areal + sq.rt.(Areal*Area2))
where: EL1, EL2 = Lower and upper elevations of the increment
Areal,Area2 =Areas computed for ELl, EL2, respectively
Volume = Incremental volume between EL1 and EL2
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:20:04 Date: 07/14/2007

Type.... Outlet Input Data Page 5.01
Name.... OUTLET
File.... R:\2006J0B5\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 1 (Q2 ANALYSIS - 7-14-07).PPW
REQUESTED POND WS ELEVATIONS:
Min. Elev.= 262.00 ft
Increment = .50 ft
Max. Elev.= 271.00 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 SP ---> CV 269.200 271.000
Orifice-Circular OR ---> CV 267.500 271.000
Culvert-Circular CV ---> TW 261.500 271.000
Weir-Rectangular WR ---> TW 269.600 271.000
TW SETUP, DS Channel
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:20:04 Date: 07/14/2007

Type.... Outlet Input Data Page 5.02 '
Name.... OUTLET
File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS '
- WET DETENTION BASIN 1 (Q2 ANALYSIS - 7-14-07).PPW
OUTLET STRUCTURE INPUT DATA
Structure ID = SP
Structure Type
----------------- = Stand Pipe
-------------
-

# of Openings
= 1 -----
Invert Elev. = 269.20 ft
Diameter = 4.0000 ft
Orifice Area = 12.5664 sq.ft
Orifice Coeff. _ .600
Weir Length = 12.57 ft
Weir Coeff. = 3.000
K, Submerged = .000
K, Reverse = 1.000
Kb,Barrel = .000000 (per ft of full flow)
Barrel Length = .00 ft
Mannings n = .0000
Structure ID = OR
Structure Type = Orifice-Circular
------------------------------------
# of Openings = 1
Invert Elev. = 267.50 ft
Diameter = .1700 ft
Orifice Coeff. _ .600
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:20:04 Date: 07/14/2007

' Type.... Outlet Input Data Page 5.03
Name.... OUTLET
File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 1 (Q2 ANALYSIS - 7-14-07).PPW
' OUTLET STRUCTURE INPUT DATA
' Structure ID = CV
Structure Type = Culvert-Circular
------------------------------------
No. Barrels 1
Barrel Diameter 1.5000 ft
Upstream Invert 261.50 ft
Dnstream Invert = 260.50 ft
Horiz. Length 100.00 ft
Barrel Length 100.01 ft
Barret Slope = .01000 ft/ft
' OUTLET CONTROL DATA...
Mannings n .0130
Ke = .5000 (forward entrance loss)
Kb .018213 (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 = 263.23 ft --> Flow = 7.58 cfs
At T2 Elev = 263.45 ft --> Flow = 8.66 cfs
S/N: 621802506A84 Bass Nixon & Kennedy Inc
' PondPack Ver. 7.5 (786c) Compute Time: 10:20:04 Date: 07/14/2007

Type.... Outlet Input Data Page 5.04 '
Name.... OUTLET
Fite.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS '
- WET DETENTION BASIN 1 (Q2 ANALYSIS - 7-14-07).PPW
OUTLET STRUCTURE INPUT DATA
Structure ID = WR
Structure Type = Weir-Rectan
ular '
g
------------------------------------
# of Openings = 1
Crest Elev. = 269.60 ft ,
Weir Length = 30.00 ft
Weir Coeff. = 3.000000
Weir TW effects (Use adjustment equation) '
'
Structure ID =
TW
Structure Type = TW SETUP, DS Channel
FREE OUTFACE CONDITIONS SPE
F
D
CI
IE
CONVERGENCE TOLERANCES...
Maximum Iterations= 30 '
Min. TW tolerance = .O1 ft
Max. TW tolerance = .O1 ft
Min. HW tolerance = .O1 ft

Max. HW tolerance = .O1 ft '
Min. Q tolerance = .10 cfs
Max. Q tolerance = .10 cfs
'

S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:20:04 Date: 07/14/2007 '

' Type.... Composite Rating Curve
Name.... OUTLET
Page 5.05
' File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 1 (Q2 ANALYSIS - 7-14-07).PPW
' ***** COMPOSITE OUTFLOW SUMMARY ****
WS Elev, Total Q Notes
' -------- -------- ----- --- Converge -------- -----------------
Elev. Q TW Etev Error
ft cfs ft +/-ft Contribu ting Structures
-
--------
' 262.00 -------
.00 -----
Free --- ----- -
Outfall --------
(no Q: --------
--------
SP,OR,CV,WR)
262.50 .00 Free Outfall (no Q: SP,OR,CV,WR)
263.00 .00 Free Outfall (no Q: SP,OR,CV,WR)
263.50 .00 Free Outfall (no Q: SP,OR,CV,WR)
'
264.00 .00 Free Outfall (no Q: SP,OR,CV,WR)
264.50 .00 Free Outfall (no Q: SP,OR,CV,WR)
265.00 .00 Free Outfatl (no Q: SP,OR,CV,WR)
' 265.50 .00 Free Outfalt (no Q: SP,OR,CV,WR)
266.00 .00 Free Outfall (no Q: SP,OR,CV,WR)
266.50 .00 Free Outfall (no Q: SP,OR,CV,WR)
267.00 .00 Free Outfatl (no Q: SP,OR,CV,WR)
267.50 .00 Free Outfalt (no Q: SP,OR,CV,WR)
268.00 .07 Free Outfalt OR,CV ( no Q: SP,WR)
268.50 .10 Free Outfall OR,CV ( no Q: SP,WR)
269.00 .13 Free Outfall OR,CV ( no Q: SP,WR)
269.20 .14 Free Outfall OR,CV ( no Q: SP,WR)
269.50 6.34 Free Outfall SP,OR,CV (no Q: WR)
269.60 9.69 Free Outfall SP,OR,CV (no Q: WR)
270.00 44.78 Free Outfalt SP,CV,WR (no Q: OR)
270.50 99.53 Free Outfall SP,CV,WR (no Q: OR)
271.00 172.43 Free Outfall SP,CV,WR (no Q: OR)
S/N: 621802506A84 Bass Nixon & Kennedy Inc
' PondPack Ver. 7.5 (786c) Compute Time: 10:20:04 Date: 07/14/Z007

Type.... Pond Routing Summary Page 6.01 '
Name.... POND 1 OUT Tag: 2-Year Event: 2 yr
Fite.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 1 (Q2 ANALYSIS - 7-14-07).PPW '
Storm... TypeII 24hr Tag: 2-Year
LEVEL POOL ROUTING SUMMARY

HYG Dir = R:\2006J065\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\ '
Inflow HYG file = NONE STORED - POND 1 IN 2-Year
Outflow HYG file = NONE STORED - POND 1 OUT 2-Year
Pond Node Data = POND 1
Pond Volume Data = POND 1
Pond Outlet Data = OUTLET ,
No Infiltration
INITIAL CONDITIONS '
----------------------------------
Starting WS Elev = 267.50 ft
Starting Volume = 1.216 ac-ft

Starting Outflow = .00 cfs t
Starting Infiltr. _ .00 cfs
Starting Total Qout= .00 cfs

Time Increment = .0500 hrs '
INFLOW/OUTFLOW HYDROGRAPH SUMMARY
Peak Inflow = 27.81 cfs at 11.9000 hrs
Peak Outflow = 4.48 cfs at 12.1500 hrs
----
Peak ---------------
Elevation = -----------
269.41 -----------------------
ft
Peak
----
---- Storage =
---------------
--------------- 2.104
-----------
----------- ac-ft
-----------------------
-----------------------
MASS BALANCE (ac-ft)
--------------------
+ Initial Vol =
+ HYG Vol IN =
- Infiltration =
- HYG Vol OUT =
- Retained Vol =
Unrouted Vol =
1.216
1.571
.000
1.425
1.360
-.003 ac-ft (.180% of Inflow Volume)
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:20:04 Date: 07/14/2007

Appendix A
Index of Starting Page Numbers for ID Names
----- B -----
BASIN D.A. 2-Year... 3.01
----- 0 -----
OUTLET... 5.01, 5.05
----- P -----
POND 1... 4.01, 6.01
----- R -----
Raleigh... 2.01
----- W -----
Watershed... 1.01
A-1
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:20:04 Date: 07/14/2007

Job File: R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD
APARTMENTS - WET DETENTION BASIN 1 (Q10 ANALYSIS - 7-14-07).PPW
' Rain Dir: C:\HAESTAD\PPKW\RAINFALL\
JOB TITLE
COLONIAL GRAND AT WAKEFIELD APARTMENTS
WET DETENTION BASIN N0. 1
Q10 ROUTING CALCULATIONS
' The following calculations are the routing calculations for the
Colonial Grand at Wakefield Apartments in Raleigh, North Carolina.
Wet Detention Basin Nos. 1 and 2 are designed to provide 85% TSS
removal as required by the NCDWQ and also to reduce the Q2 and Q10
' post-developed discharge to less than or equal to the Q2 and Q10
pre-developed discharge for each point of discharge as required by
the City of Raleigh. The basins are also designed to pass the
Q100 storm without overtopping the dam. The site stormwater
calculations were performed using the Rational Method. The
attached routing calculations were performed using the SCS
methodology. The SCS curve number was manipulated so that the
' discharge for the respective storm will equal the discharge based
on the Rational Equation.
S/N: 621802506A84 Bass Nixon & Kennedy Inc
' PondPack Ver. 7.5 (786c) Compute Time: 10:15:51 Date: 07/14/2007

Tabte of Contents
i
Tabte of Contents
********************** MASTER SUMMARY **********************
Watershed....... Master Network Summary ............. 1.01
****************** DESIGN STORMS SUMMARY *******************
Raleigh......... Design Storms ...................... 2.01
******************** RUNOFF HYDROGRAPHS ********************
BASIN D.A...... 10-Yea
SCS Unit Hyd. Summary .............. 3.01
**********s*****:****** POND VOLUMES *****s*****************
POND 1.......... Vot: Elev-Area ..................... 4.01
******************** OUTLET STRUCTURES *********************
OUTLET.......... Outlet Input Data .................. 5.01
Composite Rating Curve ............. 5.05
*********************:* POND ROUTING ****::*****************
POND 1 OUT 10-Yea
Pond Routing Summary ............... 6.01
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:15:51 Date: 07/14/2007

Type.... Master Network Summary Page 1.01
Name.... Watershed
File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 1 (Q10 ANALYSIS - 7-14-07).PPW
MASTER DESIGN STORM SUMMARY
Default Network Design Storm File, ID STORMS.RNQ Raleigh
Total
Depth Rainfall
Return Event in Type RNF Fite RNF ID
------------
10-Yea ------ ---------------- --------
5.3800 Synthetic Curve SCSTYPES ----------------
TypeII 24hr
MASTER NETWORK SUMMARY
SCS Unit Hydrograph Method
(*Node=Outfatl; +Node=Diversion;)
(Trun= HYG Truncation: Btank=None; L=Left; R=Rt; LR=Left&Rt)
Max
Return HYG Vot Qpeak Qpeak Max WSEL Pond
Storage
Node
------ ID
----------- Type Event ac-ft Trun hrs
---- ------ ---------- -- --------- cfs ft ac-ft
-------- -------- ---------
BASIN D.A. AREA 10 1.928 11.9000 34.86
*DISCH ARGE PT 1 JCT 10 1.789 12.1000 8.41
POND 1 IN POND 10 1.928 11.9000 34.86
POND 1 OUT POND 10 1.789 12.1000 8.41 269.56
2.182
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:15:51 Date: 07/14/2007

Type.... Design Storms Page 2.01
Name.... Raleigh
File.... C:\HAESTAD\PPKW\RAINFALL\STORMS.RNQ
Title... COLONIAL GRAND AT WAKEFIELD APARTMENTS
WET DETENTION BASIN N0. 1
Q10 ROUTING CALCULATIONS
The following calculations are the routing
calculations for the Colonial Grand at Wakefield
Apartments in Raleigh, North Carolina. Wet Detention
Basin Nos. 1 and 2 are designed to provide 85% TSS
removal as required by the NCDWQ and also to reduce
the Q2 and Q10 post-developed discharge to less than
or equal to the Q2 and Q10 pre-developed discharge
for each point of discharge as required by the City
of Raleigh. The basins are also designed to pass the
Q100 storm without overtopping the dam. The site
stormwater calculations were performed using the
Rational Method. The attached routing calculations
were performed using the SCS methodology. The SCS
curve number was manipulated so that the discharge
for the respective storm will equal the discharge
based on the Rational Equation.
DESIGN STORMS SUMMARY
Design Storm File,ID = STORMS.RNQ Raleigh
Storm Tag Name = 10-Yea
Data Type, File, ID = Synthetic Storm SCSTYPES.RNF TypeII 24hr
Storm Frequency = 10 yr
Total Rainfall Depth= 5.3800 in
Duration Multiplier = 1
Resulting Duration = 24.0000 hrs
Resulting Start Time= .0000 hrs Step= .1000 hrs End= 24.0000 hrs
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:15:51 Date: 07/14/2007

Type.... SCS Unit Hyd. Summary Page 3.01
Name.... BASIN D.A. Tag: 10-Yea Event: 10 yr
' File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 1 (Q10 ANALYSIS - 7-14-07).PPW
Storm... TypeII 24hr Tag: 10-Yea
SCS UNIT HYDROGRAPH METHOD
STORM EVENT: 10 year storm
Duration = 24.0000 hrs Rain Depth = 5.3800 in
' Rain Dir = C:\HAESTAD\PPKW\RAINFALL\
Rain File -ID = SCSTYPES.RNF - TypeII 24hr
Unit Hyd Type = Default Curvilinear
HYG Dir R~\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL
CALCS\
HYG File - ID - BASIN D.A. 10-Yea
Tc (Min. Tc) _ .0833 hrs
' Drainage Area = 6.900 acres Runoff CN= 81
--------------------------------------------
--------------------------------------------
' Computational Time Increment .01111 hrs
Computed Peak Time 11.9175 hrs
Computed Peak Flow 36.11 cfs
' Time Increment for HYG File = .0500 hrs
Peak Time, Interpolated Output = 11.9000 hrs
Peak Ftow, Interpolated Output = 34.86 cfs
--------------------------------------------
--------------------------------------------
' DRAINAGE AREA
-------------------
' ID:None Selected
CN 81
Area = 6.900 acres
S = 2.3001 in
' 0.25 = .4600 in
Cumulative Runoff
-------------------
3.3526 in
1.928 ac-ft
' HYG Volume... 1.928 ac-ft (area under HYG curve)
***** UNIT HYDROGRAPH PARAMETERS *****
' Time Concentration, Tc = .08330 hrs (ID: None Selected)
Computational Incr, Tm = .01111 hrs = 0.20000 Tp
Unit Hyd. Shape Factor = 483.432 (37.46% under rising limb)
' K = 483.43/645.333, K = .7491 (also, K = 2/(1+(Tr/Tp))
Receding/Rising, Tr/Tp = 1.6698 (solved from K = .7491)
' Unit peak, qp = 93.85 cfs
Unit peak time Tp = .05553 hrs
Unit receding limb, Tr = .22213 hrs
Total unit time, Tb = .27767 hrs
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:15:51 Date: 07/14/2007

Type.... Vol: Elev-Area
Name.... POND 1
Page 4.01
File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS '
- WET DETENTION BASIN 1 (Q10 ANALYSIS - 7-14-07).PPW
Title... Wet Detention Basin No. 1
Elevation Planimeter Area Al+A2+sgr(A1*A2) Volume Volume Sum
(ft)
------------ (sq:in) (acres)
--------------------- (acres)
------------ (ac-ft) (ac-ft)

262.00
----- .1180 ----
.0000 ----------
.000 -------------
.000
264.00 ----- .1788 .4421 .295 .295
266.00 ----- .2577 .6512 .434 .729
268.00 ----- .4498 1.0480 .699 1.427
270.00 ----- .5379 1.4796 .986 2.414
271.00 ----- .5968 1.7013 .567 2.981
POND VOLUME EQUATIONS
* Incremental volume computed by the Conic Method for Reservoir Volumes.
Volume = (1/3) * (EL2-EL1) * (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 EL1 and EL2
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:15:51 Date: 07/14/2007

Type.... Outlet Input Data Page 5.01
Name.... OUTLET
Fite.... R:\2006J065\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 1 (Q10 ANALYSIS - 7-14-07).PPW
REQUESTED POND WS ELEVATIONS:
Min. Elev.= 262.00 ft
Increment = .50 ft
Max. Elev.= 271.00 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 SP ---> CV 269.200 271.000
Orifice-Circular OR ---> CV 267.500 271.000
Culvert-Circular CV ---> TW 261.500 271.000
Weir-Rectangular WR ---> TW 269.600 271.000
TW SETUP, DS Channel
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:15:51 Date: 07/14/2007

Type.... Outlet Input Data Page 5.02 '
Name.... OUTLET
File.... R:\2006J0B5\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS '
- WET DETENTION BASIN 1 (Q10 ANALYSIS - 7-14-07).PPW
OUTLET STRUCTURE INPUT DATA
Structure ID = SP
Structure Type
----------------- = Stand Pipe
-------------
------
# of Openings = 1
Invert Elev. = 269.20 ft
Diameter = 4.0000 ft
Orifice Area = 12.5664 sq.ft
Orifice Coeff. _ .600
Weir Length = 12.57 ft
Weir Coeff. = 3.000
K, Submerged = .000
K, Reverse = 1.000.
Kb,Barrel = .000000 (per ft of full flow)
Barrel Length = .00 ft
Mannings n = .0000
Structure ID = OR
Structure Type = Orifice-Circular
------------------------------------
# of Openings = 1
Invert Elev. = 267.50 ft
Diameter = .1700 ft
Orifice Coeff. _ .600
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:15:51 Date: 07/14/2007

Type.... Outlet Input Data Page 5.03
Name.... OUTLET
' File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 1 (Q10 ANALYSIS - 7-14-07).PPW
OUTLET STRUCTURE INPUT DATA
' Structure ID = CV
Structure Type = Culvert-Circular
------------------------------------
' No. Barrels 1
Barret Diameter 1.5000 ft
Upstream Invert = 261.50 ft
Dnstream Invert = 260.50 ft
' Horiz. Length 100.00 ft
Barrel Length 100.01 ft
Barrel Slope = .01000 ft/ft
OUTLET CONTROL DATA...
Mannings n .0130
Ke = .5000 (forward entrance loss)
' Kb .018213 (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 = 263.23 ft --> Ftow = 7.58 cfs
At T2 Elev = 263.45 ft --> Flow = 8.66 cfs
S/N: 621802506A84 Bass Nixon & Kennedy Inc
' PondPack Ver. 7.5 (786c) Compute Time: 10:15:51 Date: 07/14/2007

Type.... Outlet Input Data Page 5.04 '
Name.... OUTLET
File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS '
- WET DETENTION BASIN 1 (Q10 ANALYSIS - 7-14-07).PPW
OUTLET STRUCTURE INPUT DATA
Structure ID = WR '
Structure Type = Weir-Rectangular
------------------------------------
# of Openings = 1
Crest Elev. = 269.60 ft ,
Weir Length = 30.00 ft
Weir Coeff. = 3.000000
Weir TW effects (Use adjustment equation)
Structure ID = TW
Structure Type = TW SETUP, DS Channel
------------------------------------
FREE OUTFACE 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 = .O1 ft
Min. Q tolerance = .10 cfs
Max. Q tolerance = .10 cfs
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:15:51 Date: 07/14/2007

' Type.... Composite Rating Curve
Name.... OUTLET
Page 5.05
' File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 1 (Q10 ANALYSIS - 7-14-07).PPW
' ***** COMPOSITE OUTFLOW SUMMARY ****
WS Elev, Total Q Notes
' -------- -------- ------ -- Converge ------- ------------------
Elev. Q TW Elev Error
ft cfs ft +/-ft Contrib uting Structures
--------
' 262.00 -------
.00 ------
Free -- ----- -
Outfall -------
(no Q: ------------------
SP,OR,CV,WR)
262.50 .00 Free Outfall (no Q: SP,OR,CV,WR)
263.00 .00 Free Outfall (no Q: SP,OR,CV,WR)
263.50 .00 Free Outfall (no Q: SP,OR,CV,WR)
'
264.00 .00 Free Outfall (no Q: SP,OR,CV,WR)
264.50 .00 Free Outfalt (no Q: SP,OR,CV,WR)
265.00 .00 Free Outfall (no Q: SP,OR,CV,WR)
' 265.50 .00 Free Outfall (no Q: SP,OR,CV,WR)
266.00 .00 Free Outfall (no Q: SP,OR,CV,WR)
266.50 .00 Free Outfall (no Q: SP,OR,CV,WR)
267.00 .00 Free Outfall (no Q: SP,OR,CV,WR)
'
267.50 .00 Free Outfall (no Q: SP,OR,CV,WR)
268.00 .07 Free Outfall OR,CV (no Q: SP,WR)
268.50 .10 Free Outfall OR,CV (no Q: SP,WR)
269.00 .13 Free Outfall OR,CV (no Q: SP,WR)
269.20 .14 Free Outfall OR,CV (no Q: SP,WR)
269.50 6.34 Free Outfall SP,OR,CV (no Q: WR)
269.60 9.69 Free Outfall SP,OR,CV (no Q: WR)
' 270.00 44.78 Free Outfall SP,CV,WR (no Q: OR)
270.50 99.53 Free Outfall SP,CV,WR (no Q: OR)
271.00 172.43 Free Outfall SP,CV,WR (no Q: OR)
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:15:51 Date: 07/14/2007

Type.... Pond Routing Summary Page 6.01 '
Name.... POND 1 OUT Tag: 10-Yea Event: 10 yr
File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 1 (Q10 ANALYSIS - 7-14-07).PPW ,
Storm... TypeII 24hr Tag: 10-Yea
LEVEL POOL ROUTING SUMMARY
HYG Dir = R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\
Inflow HYG file = NONE STORED - POND 1 IN 10-Yea
Outflow HYG file = NONE STORED - POND 1 OUT 10-Yea
Pond Node Data = POND 1
Pond Volume Data = POND 1
Pond Outlet Data = OUTLET
No Infiltration
INITIAL CONDITIONS
Starting WS Elev = 267.50 ft
Starting Volume = 1.216 ac-ft
Starting Outflow = .00 cfs
Starting Infiltr. _ .00 cfs
Starting Total Qout= .00 cfs
Time Increment = .0500 hrs
INFLOW/OUTFLOW HYDROGRAPH SUMMARY
Peak Inflow = 34.86 cfs at 11.9000 hrs
Peak Outflow = 8.41 cfs at 12.1000 hrs
-----
Peak --------------
Elevation = -----------
269.56 -----------------------
ft
Peak Storage = 2.182 ac-ft
MASS BALANCE
------------- (ac-ft)
----

+ Initial Vol ---------
= 1.216
+ HYG Vol IN = 1.928
- Infiltration = .000
- HYG Vot OUT = 1.789
- Retained Vol = 1.351
Unrouted Vot = -.003 ac-ft
(.156% of Inflow Volume)
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:15:51 Date: 07/14/2007

Appendix A
Index of Starting Page Numbers for ID Names
----- B -----
BASIN D.A. 10-Yea... 3.01
----- 0 -----
OUTLET... 5.01, 5.05
----- P -----
POND 1... 4.01, 6.01
----- R -----
Raleigh... 2.01
----- W -----
Watershed... 1.01
A-1
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:15:51 Date: 07/14/2007

r Job Fite: R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD
APARTMENTS - WET DETENTION BASIN 1 (Q100 ANALYSIS - 7-14-07).PPW
Rain Dir: C:\HAESTAD\PPKW\RAINFALL\
JOB TITLE
COLONIAL GRAND AT WAKEFIELD APARTMENTS
' WET DETENTION BASIN N0. 1
Q100 ROUTING CALCULATIONS
The following calculations are the routing calculations for the
' Colonial Grand at Wakefield Apartments in Raleigh, North Carolina.
Wet Detention Basin Nos. 1 and 2 are designed to provide 85% TSS
removal as required by the NCDWQ and also to reduce the Q2 and Q10
' post-developed discharge to less than or equal to the Q2 and Q10
pre-developed discharge for each point of discharge as required by
the City of Raleigh. The basins are also designed to pass the
Q100 storm without overtopping the dam. The site stormwater
' calculations were performed using the Rational Method. The
attached routing calculations were performed using the SCS
methodology. The SCS curve number was manipulated so that the
discharge for the respective storm will equal the discharge based
on the Rational Equation.

1

5/N: 621802506A84 Bass Nixon & Kennedy Inc
' PondPack Ver. 7.5 (786c) Compute Time: 10:23:59 Date: 07/14/2007

Table of Contents
Table of Contents
i
********************** MASTER SUMMARY **********************
Watershed....... Master Network Summary ............. 1.01
****************** DESIGN STORMS SUMMARY *******************
Raleigh......... Design Storms ...................... 2.01
******************** RUNOFF HYDROGRAPHS ********************
BASIN D.A...... 100-Ye
SCS Unit Hyd. Summary .............. 3.01
**********:************ POND VOLUMES *******************:***
POND 1.......... Vot: Elev-Area ..................... 4.01
******************** OUTLET STRUCTURES *********************
OUTLET.......... Outlet Input Data .................. 5.01
Composite Rating Curve ............. 5.05
*********************** POND ROUTING ***********************
POND 1 OUT 100-Ye
Pond Routing Summary ............... 6.01
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:23:59 Date: 07/14/2007

Type.... Master Network Summary Page 1.01
Name.... Watershed
File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 1 (Q100 ANALYSIS - 7-14-07).PPW
MASTER DESIGN STORM SUMMARY
Default Network Design Storm Fite, ID STORMS.RNQ Raleigh
Total
Depth Rainfall
Return Event in Type RNF Fite RNF ID
------------ ------ ---------------- -------- ----------------
100-Ye 8.0000 Synthetic Curve SCSTYPES TypeII 24hr
MASTER NETWORK SUMMARY
SCS Unit Hydrograph Method
(*Node=Outfatt; +Node=Diversion;)
(Trun= HYG Truncation: Blank=None; L=Left; R=Rt; LR=Left&Rt)
Return HYG Vol
Storage
Node ID
-------------- Type
--- ---- Event
------ ac-ft Trun
---------- --
BASIN D.A. AREA 100 2.593
*DISCHARGE PT 1 JCT 100 2.458
POND 1 IN POND 100 2.593
POND 1 OUT POND 100 2.458
2.302
Max
Qpeak Qpeak Max WSEL Pond
hrs
--------- cfs ft ac-ft
-------- -------- ---------
11.9000 46.90
12.0500 26.33
11.9000 46.90
12.0500 26.33 269.79
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:23:59 Date: 07/14/2007

Type.... Design Storms
Name.... Raleigh
File.... C:\HAESTAD\PPKW\RAINFALL\STORMS.RNQ
Title... COLONIAL GRAND AT WAKEFIELD APARTMENTS
WET DETENTION BASIN N0. 1
Q100 ROUTING CALCULATIONS
The following calculations are the routing
calculations for the Colonial Grand at Wakefield
Apartments in Raleigh, North Carolina. Wet Detention
Basin Nos. 1 and 2 are designed to provide 85% TSS
removal as required by the NCDWQ and also to reduce
the Q2 and Q10 post-developed discharge to less than
or equal to the Q2 and Q10 pre-developed discharge
for each point of discharge as required by the City
of Raleigh. The basins are also designed to pass the
Q100 storm without overtopping the dam. The site
stormwater calculations were performed using the
Rational Method. The attached routing calculations
were performed using the SCS methodology. The SCS
curve number was manipulated so that the discharge
for the respective storm will equal the discharge
based on the Rational Equation.
DESIGN STORMS SUMMARY
Design Storm File,ID = STORMS.RNQ Raleigh
Storm Tag Name = 100-Ye
Page 2.01
Data Type, File, ID = Synthetic Storm SCSTYPES.RNF TypeII 24hr
Storm Frequency = 100 yr
Total Rainfall Depth= 8.0000 in
Duration Multiplier = 1
Resulting Duration = 24.0000 hrs
Resulting Start Time= .0000 hrs Step= .1000 hrs End= 24.0000 hrs
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:23:59 Date: 07/14/2007

Type.... SCS Unit Hyd. Summary Page 3.01
Name.... BASIN D.A. Tag: 100-Ye Event: 100 yr
Fite.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 1 (Q100 ANALYSIS - 7-14-07).PPW
Storm... TypeII 24hr Tag: 100-Ye
CALCS\
SCS UNIT HYDROGRAPH METHOD
STORM EVENT: 100 year storm
Duration = 24.0000 hrs Rain Depth = 8.0000 in
Rain Dir = C:\HAESTAD\PPKW\RAINFALL\
Rain File -ID = SCSTYPES.RNF - TypeII 24hr
Unit Hyd Type = Default Curvilinear
HYG Dir = R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL
HYG File - ID = - BASIN D.A. 100-Ye
Tc (Min. Tc) _ .0833 hrs
Drainage Area = 6.900 acres Runoff CN= 70
Computational Time Increment = .01111 hrs
Computed Peak Time 11.9175 hrs
Computed Peak Flow 48.81 cfs
Time Increment for HYG File
Peak Time, Interpolated Output = .0500
11.9000 hrs
hrs
Peak Flow, Interpolated Output 46.90 cfs
DRAINAGE AREA
ID:None Selected
CN = 70
Area = 6.900 acres
S = 4.2045 in
0.25 = .8409 in
Cumulative Runoff
-------------------
4.5102 in
2.593 ac-fit
HYG Volume... 2.593 ac-ft (area under HYG curve)
***** UNIT HYDROGRAPH PARAMETERS *****
Time Concentration, Tc = .08330 hrs (ID: None Selected)
' Computational Incr, Tm = .01111 hrs = 0.20000 Tp
Unit Hyd. Shape Fact or = 483.432 (37.46% under rising limb)
K = 483.43/645.333, K = .7491 (also, K = 2/(1+(Tr/Tp))
' Receding/Rising, Tr/ Tp = 1.6698 (solved from K = .7491)
Unit peak, qp = 93.85 cfs
' Unit peak time Tp = .05553 hrs
Unit receding limb, Tr = .22213 hrs
Total unit time, Tb = .27767 hrs

S/N: 621802506A84 Bass Nixon & Kennedy Inc
' PondPack Ver. 7.5 (786c) Compute Time: 10:23:59 Date: 07/14/2007

Type.... Vol: Etev-Area
Name.... POND 1
Page 4.01
File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 1 (Q100 ANALYSIS - 7-14-07).PPW
Title... Wet Detention Basin No. 1
Elevation Ptanimeter Area Al+A2+sgr(A1*A2) Volume Volume Sum
(ft) (sq.in) (acres)
--------- (acres)
----------------- (ac-ft)
--------- (ac-ft)
-------------
------------
262.00 ------------
----- .1180 .0000 .000 .000
264.00 ----- .1788 .4421 .295 .295
266.00 ----- .2577 .6512 .434 .729
268.00 ----- .4498 1.0480 .699 1.427
270.00 ----- .5379 1.4796 .986 2.414
271.00 ----- .5968 1.7013 .567 2.981
POND VOLUME EQUATIONS
* Incremental volume computed by the Conic Method for Reservoir Volumes.
Volume = (1/3) * (EL2-EL1) * (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 EL1 and EL2
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:23:59 Date: 07/14/2007

Type.... Outlet Input Data Page 5.01
Name.... OUTLET
File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 1 (Q100 ANALYSIS - 7-14-07).PPW
REQUESTED POND WS ELEVATIONS:
Min. Elev.= 262.00 ft
Increment = .50 ft
Max. Elev.= 271.00 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 SP ---> CV 269.200 271.000
Orifice-Circular OR ---> CV 267.500 271.000
Culvert-Circular CV ---> TW 261.500 271.000
Weir-Rectangular WR ---> TW 269.600 271.000
TW SETUP, DS Channel
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:23:59 Date: 07/14/2007

Type.... Outlet Input Data Page 5.02 '
Name.... OUTLET
File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS '
- WET DETENTION BASIN 1 (Q100 ANALYSIS - 7-14-07).PPW
OUTLET STRUCTURE INPUT DATA ,
Structure ID = SP '
Structure Type = Stand Pipe
# of Openings = 1
Invert Elev. = 269.20 ft
Diameter = 4.0000 ft
Orifice Area = 12.5664 sq.ft
Orifice Coeff. _ .600
Weir Length = 12.57 ft
Weir Coeff. = 3.000
K, Submerged = .000
K, Reverse = 1.000
Kb,Barrel = .000000 (per ft of full flow)
Barret Length = .00 ft
Mannings n = .0000
Structure ID = OR
Structure Type = Orifice-Circular
------------------------------------
# of Openings = 1
Invert Elev. = 267.50 ft
Diameter = .1700 ft
Orifice Coeff. _ .600
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:23:59 Date: 07/14/2007

t Type.... Outlet Input Data Page 5.03
Name.... OUTLET
' File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 1 (Q100 ANALYSIS - 7-14-07).PPW
' OUTLET STRUCTURE INPUT DATA
' Structure ID = CV
Structure Type = Culvert-Circular
------------------------------------
' No. Barrels 1
Barrel Diameter 1.5000 ft
Upstream Invert 261.50 ft
Dnstream Invert = 260.50 ft
Horiz. Length 100.00 ft
Barrel Length 100.01 ft
Barrel Slope = .01000 ft/ft
1 OUTLET CONTROL DATA...
Mannings n .0130
Ke = .5000 (forward entrance loss)
' Kb .018213 (per ft of full flow)
Kr .5000 (reverse entrance toss)
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 = 263.23 ft _--> Flow = 7.58 cfs
At T2 Elev = 263.45 ft --> Flow = 8.66 cfs
S/N: 621802506A84 Bass Nixon & Kennedy Inc
' PondPack Ver. 7.5 (786c) Compute Time: 10:23:59 Date: 07/14/2007

Type.... Outlet Input Data Page 5.04 ,
Name.... OUTLET
Fite.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS '
- WET DETENTION BASIN 1 (Q100 ANALYSIS - 7-14-07).PPW
OUTLET STRUCTIIRF TNPIIT t)ATA
Structure ID
Structure Type
--------------
# of Openings
Crest Elev.
Weir Length
Weir Coeff.
WR
Weir-Rectangular
----------------
1
269.60 ft
30.00 ft
3.000000
Weir TW effects (Use adjustment equation)
Structure ID = TW
Structure Type = TW SETUP, DS Channel
------------------------------------
FREE OUTFACE CONDITIONS SPECIFIED
CONVERGENCE TOLERANCES...
Maximum Iterations= 30
Min. TW tolerance = .O1 ft
Max. TW tolerance = .01 ft
Min. HW tolerance = .O1 ft
Max. HW tolerance = .O1 ft
Min. Q tolerance = .10 cfs
Max. Q tolerance = .10 cfs
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:23:59 Date: 07/14/2007

' Type.... Composite Rating Curve Page 5.05
Name.... OUTLET
' File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 1 (Q100 ANALYSIS - 7-14-07).PPW
' ***** COMPOSITE OUTFLOW SUMMARY ****
WS Etev, Total Q
Elev. Q
ft cfs

' --------
262.00 -------
.00
262.50 .00
263.00 .00
263.50 .00
' 264.00 .00
264.50 .00
265.00 .00
265.50 .00
266.00 .00
266.50 .00
267.00 .00
' 267.50 .00
268.00 .07
268.50 .10
269.00 .13
' 269.20 .14
269.50 6.34
269.60 9.69
' 270.00 44.78
270.50 99.53
271.00 172.43

0

1
Notes
------ -- Converge ------- ------------------
TW El ev Error
ft +/-ft Contrib uting Structures
--------
------
Free -- -----
Outfatt --------
(no Q: ----------
SP,OR,CV,WR)
Free Outfatt (no Q: SP,OR,CV,WR)
Free Outfatt (no Q: SP,OR,CV,WR)
Free Outfatl (no Q: SP,OR,CV,WR)
Free Outfatl (no Q: SP,OR,CV,WR)
Free Outfall (no Q: SP,OR,CV,WR)
Free Outfall (no Q: SP,OR,CV,WR)
Free Outfall (no Q: SP,OR,CV,WR)
Free Outfalt (no Q: SP,OR,CV,WR)
Free Outfall (no Q: SP,OR,CV,WR)
Free Outfall (no Q: SP,OR,CV,WR)
Free Outfatt (no Q: SP,OR,CV,WR)
Free Outfall OR,CV (no Q: SP,WR)
Free Outfatt OR,CV (no Q: SP,WR)
Free Outfalt OR,CV (no Q: SP,WR)
Free Outfall OR,CV (no Q: SP,WR)
Free Outfatl SP,OR,C V (no Q: WR)
Free Outfatt SP,OR,C V (no Q: WR)
Free Outfalt SP,CV,W R (no Q: OR)
Free Outfatl SP,CV,W R (no Q: OR)
Free Outfatt SP,CV,W R (no Q: OR)
S/N: 621802506A84
' PondPack Ver. 7.5 (786c)
Bass Nixon & Kennedy Inc
Compute Time: 10:23:59 Date: 07/14/2007

Type.... Pond Routing Summary Page 6.01 ,
Name.... POND 1 OUT Tag: 100-Ye Event: 100 yr
File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 1 (Q100 ANALYSIS - 7-14-07).PPW '
Storm... TypeII 24hr Tag: 100-Ye
LEVEL POOL ROUTING SUMMARY
HYG Dir = R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\
Inflow HYG file = NONE STORED - POND 1 IN 100-Ye
Outflow HYG file = NONE STORED - POND 1 OUT 100-Ye
Pond Node Data = POND 1
Pond Volume Data = POND 1
Pond Outlet Data = OUTLET
No Infiltration
INITIAL CONDITIONS
Starting WS Elev = 267.50 ft
Starting Volume = 1.216 ac-ft
Starting Outflow = .00 cfs
Starting Infiltr. _ .00 cfs
Starting Total Qout= .00 cfs
Time Increment = .0500 hrs
INFLOW/OUTFLOW HYDROGRAPH SUMMARY
Peak Inflow = 46.90 cfs at 11.9000 hrs
Peak Outflow = 26.33 cfs at 12.0500 hrs
----
Peak --------------
Elevation = ------------
269.79 -----------------------
ft
Peak
----
---- Storage =
---------------
--------------- 2.302
-----------
----------- ac-ft
-----------------------
-----------------------
MASS BALANCE (ac-ft)
----------------
-
---
+ Initial Vol = ------
1.216
+ HYG Vot IN = 2.593
- Infiltration = .000
- HYG Vol OUT = 2.458
- Retained Vot = 1.348
Unrouted Vol = -.003 ac-ft
(.118% of Inflow Volume)
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:23:59 Date: 07/14/2007

1
1
1
1
1
1
1
1
1
1
1
1
1
1
Appendix A
Index of Starting Page Numbers for ID Names
----- B -----
BASIN D.A. 100-Ye... 3.01
----- 0 -----
OUTLET... 5.01, 5.05
----- P -----
POND 1... 4.01, 6.01
----- R -----
Raleigh... 2.01
----- W -----
Watershed... 1.01
A-1
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:23:59 Date: 07/14/2007

APPENDIX C
SUMMARY OF WATER
' QUALITY BASIN DESIGN
CALCULATIONS FOR WET
DETENTION BASIN NO.2
' USING EXCEL SPREADSHEET
' Colonial Grand - Stormwater Calcs. 9 7/14/2007

' Water Qualit Retention Calculations
Y
Project Name: Colonial Grand at Wakefield -Wet Detention Basin No. 2
' Date: July 14, 2007
Determine Surface Area Required for Permanent Pool:
. Drainage Area (ac): 11.3
Impervious Area (ac): 6.9
' Percent Impervious: 61.1%
Perm. Pool Depth (ft): 3
SAlDA @ 60% 2.4 (from Table 1.1 of NCDENR's Stormwater BMP manual)
SA/DA @ 70% 2.88 (from Table 1.1 of NCDENR's Stormwater BMP manual)
'
Interpolated SA/DA: 2.45
Req. Surface Area (sf): 12,064 (at permanent pool elevation)
Perm. Pool Elevation: 275.00
Provided Surface Area (sf): 15,821 OK -Surface area requirement met
Provided Storage (cf): 47,665
' Check Hydraulic Depth (ft): 3.01 OK -Hydraulic depth requirement met
Calculate the Volume Required to Treat the First Flush:
Rainfall to Treat: 1 inch(es)
Runoff Coefficient (Rv) = 0.05 + 0.009"(% Impervious)
Runoff Coefficient (Rv): 0.60 inrn
Runoff Volume (V) =Rainfall " (Rv) " (Drainage Area)
Runoff Volume (V): 24,593 CF
' Calculate the Depth Required for the Temporar y Pool:
Perm. Pool Elevation: 275.00
Provided Surface Area (sf): 15,821 (at permanent pool elevation)
'
Provided Storage (cf): 47,665
Volume Req. for Temp. Pool (CF): 24,593 (this amount required above Perm. Pool)
Total Volume Req Temp & Perm(CF): 72,258
'
EI. Of Temp. Pool Between: 276.00 and 278.00
EI.Of Temp. Pool: 276.44
Depth of Temp. Pool (ft): 1.44 measured from perm. Pool elevation
' Determine the Orifice Size for 2-5 Dav Drawdown:
Orifice Invert Elevation: 275.00
Elevation of Temp. Pooi: 276.44
Orifice Diameter (in): 2.50
Use the orifice equation to determine flow and drawdown time:
Orifice Equation: O = C ' A " (2gh)^0.5
'
Volume to Draw Down (CF): 24,593
Flow for 2-Day Drawdown (CFS): 0.142
Flow for 5-Day Drawdown (CFS): 0.057
C; 0.6
g (SFls): 32.2
h (ft): 0.667 (average driving head to centerline of orifice)
A (sf): 0.0341
Solve Orifice Equation for Q (CFS): 0.134
'
Drawdown Time (Days): 2.12 OK -Drawdown between 2 and 5 days.

i
,.:
..
c

U
c
' c
0
m
a~
~ W
'Q U d-
o ao
Ll~ r
r c~
r N
o ti
0 o
~- o
o o
0 o
0 o
0 0
0 0
0 0
0
a r r M d; LC) In r` 0 0 0 0 0 0 0
a -- 0 0 0 0 0 0 0 0 0 0 0 0 0 0
W
~
Q N O N ~ CO OO O N Cf CO 00 0
N N
N C1'
N (fl
N
F- r r ~ ~ r
N
W O O O O O O O O O O N O

V ^
M O
CO
d'
t!~
~
M
p
(~ J <
~
N
O
r
Ct
00
~
M I`
N 0
~ 0
~ 0
~ 0
~ 0
~ 0
~ 0
~

> r M O r r N 0 0 0 0 0 0 0
W 0 0 0 0 0 0

~ M

<

O 0
(p

r 0
Op

N 0
r

'd' 0
Ln

h 0
M

f~ 0
N

~
0
0
0
0
0
0
0
0
0
0
0
0
0
0
J
Q ~ ~ ~ Cp O
0 0p
f~ 0
CO 0 0 0 0 0 0 0
~ ..~ r
r O
N r
M M d' Lf)
O
O
O
O
O
O
Q W LL 0 ~ 0 ^ ~ ~ 0 0 0 0 0 0 0
a7 O O ~ N p M ^ 0 0 0 0 0 0 0
W ~ y
... N OO ~ d~ ~ 0 0 0 0 0 0 0
~ Q 11 O LA ~ M 00
Q ~- ~ c- N N
Q N O~ OO

~ O
M r
r- ~
CO ~
O M
M
W < ~ d i.n ~ 00 0 ~ 0 0 0
Q LL
... ~ CO M
~ 00
~ r
N CO
N O
M
O O O O O O O O O O O O O O
W O O O O O O O O O O O O O O
J O N ~ Cfl o0 0 N ~ cfl 00 0 N ~ C0
W ~ n n n n O O O O O ~ d7 ~ ~
N N N N N N N N N N N N N N

APPENDIX D -

1
1

C

SUMMARY OF ROUTING
CALCULATIONS FOR WET
DETENTION BASIN N0.2
FOR THE Q2, Q10 AND Q100
STORMS USING PONDPACK
COMPUTER SOFTWARE BY
HAESTAD METHODS
' Colonial Grand - Stormwater Calcs. 10 7/14/2007

' Job Fite: R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD
APARTMENTS - WET DETENTION BASIN 2 (Q2 ANALYSIS - 7-14-07).PPW
Rain Dir: C:\HAESTAD\PPKW\RAINFALL\
JOB TITLE
COLONIAL GRAND AT WAKEFIELD APARTMENTS
' WET DETENTION BASIN N0. 2
Q2 ROUTING CALCULATIONS
' The following calculations are the routing calculations for the
Colonial Grand at Wakefield Apartments in Raleigh, North Carolina.
Wet Detention Basin Nos. 1 and 2 are designed to provide 85% TSS
removal as required by the NCDWQ and also to reduce the Q2 and Q10
' post-developed discharge to less than or equal to the Q2 and Q10
pre-developed discharge for each point of discharge as required by
the City of Raleigh. The basins are also designed to pass the
Q100 storm without overtopping the dam. The site stormwater
' calculations were performed using the Rational Method. The
attached routing calculations were performed using the SCS
methodology. The SCS curve number was manipulated so that the
discharge for the respective storm will equal the discharge based
on the Rational Equation.
S/N: 621802506A84 Bass Nixon & Kennedy Inc
' PondPack Ver. 7.5 (786c) Compute Time: 10:34:14 Date: 07/14/2007

Table of Contents
Table of Contents
i
********************** MASTER SUMMARY **********************
Watershed....... Master Network Summary ............. 1.01
****************** DESIGN STORMS SUMMARY *******************
Raleigh......... Design Storms ...................... 2.01
******************** RUNOFF HYDROGRAPHS ********************
BASIN D.A....... 2-Year
SCS Unit Hyd. Summary .............. 3.01
*************s**s****** POND VOLUMES *******s***************
POND 1.......... Vol: Etev-Area ..................... 4.01
******************** OUTLET STRUCTURES *********************
OUTLET.......... Outlet Input Data .................. 5.01
Composite Rating Curve ............. 5.04
***s******************* POND ROUTING ************:**********
SED. BASIN 2 OUT 2-Year
Pond Routing Summary. .............. 6.01
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:34:14 Date: 07/14/2007

Type.... Master Network Summary Page 1.01
Name.... Watershed
File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 2 (Q2 ANALYSIS - 7-14-07).PPW
MASTER DESIGN STORM SUMMARY
Default Network Design Storm File, ID STORMS.RNQ Rateigh
Total
Depth Rainfall
Return Event in Type RNF File RNF ID
------------ ------ ---------------- -------- ----------------
2-Year 3.6000 Synthetic Curve SCSTYPES TypeII 24hr
MASTER NETWORK SUMMARY
SCS Unit Hydrograph Method
(*Node=Outfatl; +Node=Diversion;)
(Trun= HYG Truncation: Blank=None; L=Left; R=Rt; LR=Left&Rt)
Return HYG Vot
Storage
Node ID
-------------- Type
--- ---- Event
------ ac-ft Trun
---------- --
BASIN D.A. AREA 2 2.573
*DISCHARGE PT 3 JCT 2 2.155
SED. BASIN 2 IN POND 2 2.573
SED. BASIN 2 OUT POND 2 2.155
3.173
Max
Qpeak Qpeak Max WSEL Pond
hrs
--------- cfs ft ac-ft
-------- -------- ---------
11.9000 45.55
18.4000 .66
11.9000 45.55
18.4000 .66 279.51
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:34:14 Date: 07/14/2007

Type.... Design Storms
Name.... Raleigh
File.... C:\HAESTAD\PPKW\RAINFALL\STORMS.RNQ
Title... COLONIAL GRAND AT WAKEFIELD APARTMENTS
WET DETENTION BASIN N0. 2
Q2 ROUTING CALCULATIONS
Page 2.01
The following calculations are the routing
calculations for the Colonial Grand at Wakefield
Apartments in Raleigh, North Carolina. Wet Detention
Basin Nos. 1 and 2 are designed to provide 85% TSS
removal as required by the NCDWQ and also to reduce
the Q2 and Q10 post-developed discharge to less than
or equal to the Q2 and Q10 pre-developed discharge
for each point of discharge as required by the City
of Raleigh. The basins are also designed to pass the
Q100 storm without overtopping the dam. The site
stormwater calculations were performed using the
Rational Method. The attached routing calculations
were performed using the SCS methodology. The SCS
curve number was manipulated so that the discharge
for the respective storm wilt equal the discharge
based on the Rational Equation.
DESIGN STORMS SUMMARY
Design Storm Fite,ID = STORMS.RNQ Raleigh
Storm Tag Name = 2-Year
Data Type, File, ID = Synthetic Storm SCSTYPES.RNF TypeII 24hr
Storm Frequency = 2 yr
Total Rainfall Depth= 3.6000 in
Duration Multiplier = 1
Resulting Duration = 24.0000 hrs
Resulting Start Time= .0000 hrs Step= .1000 hrs End= 24.0000 hrs
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:34:14 Date: 07/14/2007

1

' Type.... SCS Unit Hyd. Summary Page 3.01
Name.... BASIN D.A. Tag: 2-Year Event: 2 yr
File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 2 (Q2 ANALYSIS - 7-14-07).PPW
Storm... TypeII 24hr Tag: 2-Year
' SCS UNIT HYDROGRAPH METHOD
STORM EVENT: 2 year storm
Duration = 24.0000 hrs Rain Depth = 3.6000 in
Rain Dir = C:\HAESTAD\PPKW\RAINFALL\
Rain File -ID = SCSTYPES.RNF - TypeII 24hr
Unit Hyd Type = Default Curvilinear
'
CALCS\ HYG Dir R~\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL
HYG File - ID BASIN D.A. 2-Year
Tc (Min. Tc) _ .0833 hrs
' Drainage Area = 11.300 acres Runoff CN= 92

' Computational Time Increment = .01111 hrs
Computed Peak Time 11.9175 hrs
Computed Peak Ftow 46.78 cfs
Time Increment for HYG File .0500 hrs
Peak Time, Interpolated Output = 11.9000 hrs
Peak Flow, Interpolated Output 45.55 cfs
' DRAINAGE AREA
ID:None Selected
' CN = 92
Area = 11.300 a cres
S = .8696 in
' 0.25 = .1739 in
Cumulat ive Runoff
-------- -----------
2.7325 in
2.573 ac-ft
HYG Volume... 2.573 ac-ft (area under HYG curve)
' ***** ETERS * ****
UNIT HYDROGRAPH PARAM
Time Concentration, Tc = .08330 hrs (ID: None Selected)
' Computational Incr, Tm = .01111 hrs = 0.20000 Tp
Unit Hyd. Shape Factor = 483.432 (37.46% under rising limb)
K = 483.43/645.333, K = .7491 (also, K = 2 /(1+(Tr/Tp))
' Receding/Rising, Tr/Tp = 1.6698 (solved from K = .7491)
' Unit peak, qp
Unit peak time Tp 153.70
= .05553 cfs
hrs
Unit receding limb, Tr .22213 hrs
Total unit time, Tb = .27767 hrs

S/N: 621802506A84 Bass Nixon & Kennedy Inc
' PondPack Ver. 7.5 (786c) Compute Time: 10:34:14 Date: 07/14/2007

Type.... Vol: Elev-Area Page 4.01 '
Name.... POND 1
File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS '
- WET DETENTION BASIN 2 (Q2 ANALYSIS - 7-14-07).PPW
Title... Wet Detention Basin No. 2
Elevation Ptanimeter Area Al+A2+sgr(A1*A2) Volume Volume Sum
(ft)
----------- (sq.in) (acres)
---------------------- (acres)
---------------- (ac-ft)
---------- (ac-ft)
-------------
270.00 ----- .1037 .0000 .000 .000
272.00 ----- .1584 .3903 .260 .260
274.00 ----- .3106 .6908 .461 .721
276.00 ----- .4158 1.0858 .724 1.445
278.00 ----- .5019 1.3745 .916 2.361
280.00 ----- .5971 1.6464 1.098 3.459
282.00 ----- .7101 1.9584 1.306 4.764
POND VOLUME EQUATIONS
* Incremental volume computed by the Conic Method for Reservoir Volumes.
Volume = (1/3) * (EL2-EL1) * (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 EL1 and EL2
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:34:14 Date: 07/14/2007

Type.... Outlet Input Data Page 5.01
Name.... OUTLET
File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 2 (Q2 ANALYSIS - 7-14-07).PPW
REQUESTED POND WS ELEVATIONS:
Min. Elev.= 270.00 ft
Increment = .50 ft
Max. Elev.= 282.00 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
----------------- ---- ------- --------- ---------
Weir-Rectangular WR ---> TW 280.500 282.000
Stand Pipe SP ---> CV 279.500 282.000
Orifice-Circular OR ---> CV 275.000 282.000
Culvert-Circular CV ---> TW 269.500 282.000
TW SETUP, DS Channel
S/N: 621802506A84 Bass Nixon & Kennedy Inc
' PondPack Ver. 7.5 (786c) Compute Time: 10:34:14 Date: 07/14/2007

Type.... Outlet Input Data Page 5.02 ,
Name.... OUTLET
Fite.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS ,
- WET DETENTION BASIN 2 (Q2 ANALYSIS - 7-14-07).PPW
OUTLET STRUCTURE INPUT DATA
Structure ID
Structure Type
--------------
# of Openings
Crest Elev.
Weir Length
Weir Coeff.
WR
Weir-Rectangular
----------------
1
280.50 ft
30.00 ft
3.000000
Weir TW effects (Use adjustment equation)
Structure ID = SP
Structure Type = Stand Pipe
-----------------
# of Openings -------------
= 1 ------
Invert Elev. = 279.50 ft
Diameter = 4.0000 ft
Orifice Area = 12.5664 sq.ft
Orifice Coeff. _ .600
Weir Length = 12.57 ft
Weir Coeff. = 3.000
K, Submerged = .000
K, Reverse = 1.000
Kb,Barrel = .000000 (per ft of full flow)
Barret Length = .00 ft
Mannings n = .0000
Structure ID = OR
Structure Type = Orifice-Circular
------------------------------------
# of Openings = 1
Invert Elev. = 275.00 ft
Diameter = .2080 ft
Orifice Coeff. _ .600
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:34:14 Date: 07/14/2007

' Type.... Outlet Input Data Page 5.03
Name.... OUTLET
' File.... R:\Z006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 2 (Q2 ANALYSIS - 7-14-07).PPW
OUTLET STRUCTURE INPUT DATA
' Structure ID = CV
Structure Type = Culvert-Circular
-----------------
No. Barrels ------------
1 -------
Barrel Diameter 1.5000 ft
Upstream Invert 269.50 ft
Dnstream Invert = 264.00 ft
Horiz. Length 150.00 ft
'
Barret Length 150.10 ft
Barrel Slope = .03667 ft/ft
' OUTLET CONTROL DATA...
Mannings n .0130
Ke = .5000 (forward entrance loss)
' Kb .018213 (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) = 1.142
T2 ratio (HW/D) 1.288
'
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 = 271.21 ft --> Flow = 7.58 cfs
At T2 Elev = 271.43 ft --> Flow = 8.66 cfs
' Structure ID = TW
Structure Type = TW SETUP, DS Channel
FREE OUTFACE CONDITIONS SPECIFIED
' CONVERGENCE TOLERANCES...
Maximum Iterations= 30
Min. TW tolerance = .01 ft
Max. TW tolerance = .01 ft
' Min. HW tolerance = .O1 ft
Max. HW tolerance = .O1 ft
Min. Q tolerance = .10 cfs
Max. Q tolerance = .10 cfs
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:34:14 Date: 07/14/2007

S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:34:14 Date: 07/14/2007

Type.... Composite Rating Curve
Name.... OUTLET
Page 5.04
File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALLS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 2 (Q2 ANALYSIS - 7-14-07).PPW
' ***** COMPOSITE OUTFLOW SUMMARY ****
WS Elev, Total Q Notes
' -------- -------- ------ -- Converge ------- ------------------
Elev. Q TW Et ev Error
ft cfs ft +/-ft Contributing Structures
270.00 .00 Free Outfall (no Q: WR,SP,OR,CV)
270.50 .00 Free Outfalt (no Q: WR,SP,OR,CV)
271.00 .00 Free Outfall (no Q: WR,SP,OR,CV)
271.50 .00 Free Outfall (no Q: WR,SP,OR,CV)
'
272.00 .00 Free Outfatt (no Q: WR,SP,OR,CV)
272.50 .00 Free Outfalt (no Q: WR,SP,OR,CV)
273.00 .00 Free Outfall (no Q: WR,SP,OR,CV)
273.50 .00 Free Outfatt (no Q: WR,SP,OR,CV)
274.00 .00 Free Outfall (no Q: WR,SP,OR,CV)
274.50 .00 Free Outfall (no Q: WR,SP,OR,CV)
275.00 .00 Free Outfall (no Q: WR,SP,OR,CV)
'
275.50 .10 Free Outfatl OR,CV (no Q: WR,SP)
276.00 .15 Free Outfall OR,CV (no Q: WR,SP)
276.50 .19 Free Outfall OR,CV (no Q: WR,SP)
277.00 .23 Free Outfalt OR,CV (no Q: WR,SP)
'
277.50 .25 Free Outfalt OR,CV (no Q: WR,SP)
278.00 .28 Free Outfall OR,CV (no Q: WR,SP)
278.50 .30 Free Outfatl OR,CV (no Q: WR,SP)
279.00 .32 Free Outfatl OR,CV (no Q: WR,SP)
279.50 .34 Free Outfall OR,CV (no Q: WR,SP)
280.00 13.69 Free Outfatt SP,OR,C V (no Q: WR)
280.50 26.68 Free Outfalt SP,CV (no Q: WR,OR)
281.00 58.95 Free Outfalt WR,SP,C V (no Q: OR)
281.50 117.56 Free Outfall WR,SP,C V (no Q: OR)
282.00 193.33 Free Outfalt WR,SP,C V (no Q: OR)
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:34:14 Date: 07/14/2007

Type.... Pond Routing Summary Page 6.01 '
Name.... SED. BASIN 2 OUT Tag: 2-Year Event: 2 yr
File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 2 (Q2 ANALYSIS - 7-14-07).PPW ,
Storm... TypeII 24hr Tag: 2-Year
LEVEL POOL ROUTING SUMMARY
HYG Dir = R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\
Inflow HYG file = NONE STORED - SED. BASIN 2 IN 2-Year
Outflow HYG file = NONE STORED - SED. BASIN 2 OUT 2-Year
Pond Node Data = SED. BASIN 2
Pond Volume Data = POND 1
Pond Outlet Data = OUTLET
No Infiltration
INITIAL CONDITIONS
Starting WS Elev = 275.00 ft
Starting Volume = 1.056 ac-ft
Starting Outflow = .00 cfs
Starting Infiltr. _ .00 cfs
Starting Total Qout= .00 cfs
Time Increment = .0500 hrs
INFLOW/OUTFLOW HYDROGRAPH SUMMARY
Peak Inflow = 45.55 cfs at 11.9000 hrs
Peak Outflow = .66 cfs at 18.4000 hrs
----
Peak ---------------
Elevation = ----------
279.51 ------------------------
ft
Peak
----
---- Storage =
---------------
--------------- 3.173
----------
---------- ac-ft
------------------------
------------------------
MASS BALANCE (ac-ft)
--------------------
+ Initial Vol = ------
1.056
+ HYG Vol IN = 2.573
- Infiltration = .000
- HYG Vol OUT = 2.155
- Retained Vol = 1.474
Unrouted Vol = -.001 ac-ft
(.024% of Inflow Volume)
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:34:14 Date: 07/14/2007

Appendix A
Index of Starting Page Numbers for ID Names
----- B -----
BASIN D.A. 2-Year... 3.01
----- 0 -----
OUTLET... 5.01, 5.04
----- P -----
POND 1... 4.01
----- R -----
Raleigh... 2.01, 6.01
----- W -----
Watershed... 1.01
A-1
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:34:14 Date: 07/14/2007

Job File: R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD
APARTMENTS - WET DETENTION BASIN 2 (Q10 ANALYSIS - 7-14-07).PPW
Rain Dir: C:\HAESTAD\PPKW\RAINFALL\
--------------------------
--------------------------
JOB TITLE
--------------------------
--------------------------
COLONIAL GRAND AT WAKEFIELD APARTMENTS
WET DETENTION BASIN N0. 2
Q10 ROUTING CALCULATIONS
The following calculations are the routing calculations for the
Colonial Grand at Wakefield Apartments in Raleigh, North Carolina.
Wet Detention Basin Nos. 1 and 2 are designed to provide 85% TSS
removal as required by the NCDWQ and also to reduce the Q2 and Q10
post-developed discharge to less than or equal to the Q2 and Q10
pre-developed discharge for each point of discharge as required by
the City of Raleigh. The basins are also designed to pass the
Q100 storm without overtopping the dam. The site stormwater
calculations were performed using the Rational Method. The
attached routing calculations were performed using the SCS
methodology. The SCS curve number was manipulated so that the
discharge for the respective storm wilt equal the discharge based
on the Rational Equation.
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:32:14 Date: 07/14/2007

Table of Contents
Table of Contents
i
*****************:**** MASTER SUMMARY **********************
Watershed....... Master Network Summary ............. 1.01
****************** DESIGN STORMS SUMMARY *******************
Raleigh......... Design Storms ...................... 2.01
******************** RUNOFF HYDROGRAPHS ********************
BASIN D.A....... 10-Yea
SCS Unit Hyd. Summary .............. 3.01
***************:******* POND VOLUMES **************s:*******
POND 1.......... Vol: Elev-Area ..................... 4.01
******************** OUTLET STRUCTURES *********************
OUTLET.......... Outlet Input Data .................. 5.01
Composite Rating Curve ............. 5.04
:********************** POND ROUTING ***********************
SED. BASIN 2 OUT 10-Yea
Pond Routing Summary ............... 6.01
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:32:14 Date: 07/14/2007

Type.... Master Network Summary Page 1.01
Name.... Watershed
Fite.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 2 (Q10 ANALYSIS - 7-14-07).PPW
MASTER DESIGN STORM SUMMARY
Default Network Design Storm File, ID STORMS.RNQ Raleigh
Total
Depth Rainfall
Return Event in Type RNF Fite RNF ID
------------
10-Yea ------
5.3800 ---------------- --------
Synthetic Curve SCSTYPES ----------------
TypeII 24hr
MAS TER NETWORK SUMMARY
SCS U nit Hydrograph Method
(*Node=Ou tfalt; +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
-------- -------- ---------
BASIN D.A. AREA 10 3.157 11.9000 57.09
*DISCH ARGE PT 3 JCT 10 2.768 13.7000 2.30
SED. BASIN 2 IN POND 10 3.157 11.9000 57.09
SED. BASIN 2 OUT POND 10 2.768 13.7000 2.30 279.57
3.208
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:32:14 Date: 07/14/2007

Type.... Design Storms
Name.... Raleigh
File.... C:\HAESTAD\PPKW\RAINFALL\STORMS.RNQ
Title... COLONIAL GRAND AT WAKEFIELD APARTMENTS
WET DETENTION BASIN N0. 2
Q10 ROUTING CALCULATIONS
The following calculations are the routing
calculations for the Colonial Grand at Wakefield
Apartments in Raleigh, North Carolina. Wet Detention
Basin Nos. 1 and 2 are designed to provide 85% TSS
removal as required by the NCDWQ and also to reduce
the Q2 and Q10 post-developed discharge to less than
or equal to the Q2 and Q10 pre-developed discharge
for each point of discharge as required by the City
of Raleigh. The basins are also designed to pass the
Q100 storm without overtopping the dam. The site
stormwater calculations were performed using the
Rational Method. The attached routing calculations
were performed using the SCS methodology. The SCS
curve number was manipulated so that the discharge
for the respective storm wilt equal the discharge
based on the Rational Equation.
DESIGN STORMS SUMMARY
Design Storm File,ID = STORMS.RNQ Raleigh
Storm Tag Name = 10-Yea
Page 2.01
Data Type, File, ID = Synthetic Storm SCSTYPES.RNF TypeII 24hr
Storm Frequency = 10 yr
Total Rainfall Depth= 5.3800 in
Duration Multiplier = 1
Resulting Duration = 24.0000 hrs
Resulting Start Time= .0000 hrs Step= .1000 hrs End= 24.0000 hrs
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:32:14 Date: 07/14/2007

' Type.... SCS Unit Hyd. Summary Page 3.01
Name.... BASIN D.A. Tag: 10-Yea Event: 10 yr
File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 2 (Q10 ANALYSIS - 7-14-07).PPW
Storm... TypeII 24hr Tag: 10-Yea
SCS UNIT HYDROGRAPH METHOD
STORM EVENT: 10 year storm
Duration = 24.0000 hrs Rain Depth = 5.3800 in
' Rain Dir = C:\HAESTAD\PPKW\RAINFALL\
Rain File -ID = SCSTYPES.RNF - TypeII 24hr
Unit Hyd Type = Default Curvilinear
' HYG Dir = R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL
CALCS\
HYG File - ID = - BASIN D.A. 10-Yea
Tc (Min. Tc) _ .0833 hrs
Drainage Area = 11.300 acres Runoff CN= 81
--------------------------------------------
--------------------------------------------
Computational Time Increment = .01111 hrs
' Computed Peak Time 11.9175 hrs
Computed Peak Flow 59.14 cfs
' Time Increment for HYG File .0500 hrs
Peak Time, Interpolated Output = 11.9000 hrs
Peak Flow, Interpolated Output 57.09 cfs
--------------------------------------------
--------------------------------------------
DRAINAGE AREA
ID:None Selected
CN = 81
Area = 11.300 acres
S = 2.3001 in
0.25 = .4600 in
Cumulative Runoff
-------------------
3.3526 in
3.157 ac-ft
HYG Volume... 3.157 ac-ft (area under HYG curve)
***** UNIT HYDROGRAPH PARAMETERS *****
Time Concentration, Tc = .08330 hrs (ID: None Selected)
'
Computational Incr, Tm = .01111 hrs = 0.20000 Tp
Unit Hyd. Shape Fact or = 483.432 (37.46% under rising limb)
K = 483.43/645.333, K = .7491 (also, K = 2/(1+(Tr/Tp))
'
Receding/Rising, Tr/ Tp = 1.6698 (solved from K = .7491)
Unit peak, qp = 153.70 cfs
' Unit peak time Tp = .05553 hrs
Unit receding limb, Tr = .22213 hrs
Total unit time, Tb = .27767 hrs
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:32:14 Date: 07/14/2007

Type.... Vot: Elev-Area Page 4.01 '
Name.... POND 1
Fite.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS'
- WET DETENTION BASIN 2 (Q10 ANALYSIS - 7-14-07).PPW
Title... Wet Detention Basin No. 2
Elevation Planimeter Area Al+A2+sgr(A1*A2) Volume Volume Sum
(ft)
------------ (sq.in) (acres)
--------------------- (acres)
-------
--- (ac-ft) (ac-ft)

270.00
----- .1037 -
------
.0000 ---------
.000 -------------
.000
272.00 ----- .1584 .3903 .260 .260
274.00 ----- .3106 .6908 .461 .721
276.00 ----- .4158 1.0858 .724 1.445
278.00 ----- .5019 1.3745 .916 2.361
280.00 ----- .5971 1.6464 1.098 3.459
282.00 ----- .7101 1.9584 1.306 4.764
POND VOLUME EQUATIONS
* Incremental volume computed by the Conic Method for Reservoir Volumes.
Volume = (1/3) * (EL2-EL1) * (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 EL1 and EL2
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:32:14 Date: 07/14/2007

1
1
1
1
1
1
Type.... Outlet Input Data Page 5.01
Name.... OUTLET
Fite.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 2 (Q10 ANALYSIS - 7-14-07).PPW
REQUESTED POND WS ELEVATIONS:
Min. Elev.= 270.00 ft
Increment = .50 ft
Max. Elev.= 282.00 ft
OUTLET CONNECTIVITY
ss~****:****:********~*«~**~:***~~************
--> Forward Flow Only (Upstream to DnStream)
<--- Reverse Flow Only .(DnStream to Upstream)
<---> Forward and Reverse Both Allowed
Structure No. Outfall E1, ft E2, ft
----------------- ---- ------- --------- ---------
Weir-Rectangular WR ---> TW 280.500 282.000
Stand Pipe SP ---> CV 279.500 282.000
Orifice-Circular OR ---> CV 275.000 282.000
Culvert-Circular CV ---> TW 269.500 282.000
TW SETUP, DS Channel
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:32:14 Date: 07/14/2007

Type.... Outlet Input Data Page 5.02 '
Name.... OUTLET
File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS '
- WET DETENTION BASIN 2 (Q10 ANALYSIS - 7-14-07).PPW
OUTLET STRUCTURE INPUT DATA
Structure ID
Structure Type
--------------
# of Openings
Crest Elev.
Weir Length
Weir Coeff.
WR
Weir-Rectangular
----------------
1
280.50 ft
30.00 ft
3.000000
Weir TW effects (Use adjustment equation)
Structure ID = SP
Structure Type
----------------- = Stand Pipe
-------------
------
# of Openings = 1
Invert Etev. = 279.50 ft
Diameter = 4.0000 ft
Orifice Area = 12.5664 sq.ft
Orifice Coeff. _ .600
Weir Length = 12.57 ft
Weir Coeff. = 3.000
K, Submerged = .000
K, Reverse = 1.000
Kb,Barrel = .000000 (per ft of full flow)
Barrel Length = .00 ft
Mannings n = .0000
Structure ID = OR
Structure Type = Orifice-Circular
------------------------------------
# of Openings = 1
Invert Etev. = 275.00 ft
Diameter = .2080 ft
Orifice Coeff. _ .600
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:32:14 Date: 07/14/2007

' Type.... Outlet Input Data Page 5.03
Name.... OUTLET
' Fite.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 2 (Q10 ANALYSIS - 7-14-07).PPW
' OUTLET STRUCTURE INPUT DATA
' Structure ID = CV
Structure Type = Culvert-Circular
------------------------------------
No. Barrels = 1
' Barret Diameter 1.5000 ft
Upstream Invert 269.50 ft
Dnstream Invert = 264.00 ft
' Horiz. Length 150.00 ft
Barrel Length 150.10 ft
Barrel Slope .03667 ft/ft
' OUTLET CONTROL DATA...
Mannings n .0130
Ke = .5000 (forward entrance loss)
Kb = .018213 (per ft of full flow)
' Kr .5000 (reverse entrance toss)
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) = 1.142
' T2 ratio (HW/D) 1.288
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 = 271.21 ft _--> Flow = 7.58 cfs
At T2 Elev = 271.43 ft --> Ftow = 8.66 cfs
1 Structure ID = TW
Structure Type = TW SETUP, DS Channel
1 ------------------------------------
FREE OUTFACE CONDITIONS SPECIFIED
CONVERGENCE TOLERANCES...
' Maximum Iterations= 30
Min. TW tolerance = .01 ft
Max. TW tolerance = .O1 ft
' Min. HW tolerance .01 ft
Max. HW tolerance = .01 ft
Min. Q tolerance .10 cfs
Max. Q tolerance = .10 cfs
S/N: 621802506A84 Bass Nixon & Kennedy Inc
' PondPack Ver. 7.5 (786c) Compute Time: 10:32:14 Date: 07/14/2007

S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:32:14 Date: 07/14/2007

Type.... Composite Rating Curve
Name.... OUTLET
Page 5.04
' File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 2 (Q10 ANALYSIS - 7-14-07).PPW
' ***** COMPOSITE OUTFLOW SUMMARY ****
WS Elev, Total Q Notes
---------------- ----- --- Converge ------- ------------------
Elev. Q TW Elev Error
ft cfs ft +/-ft Contributing Structures
--------
270.00 -------
.00 -----
Free --- -----
Outfalt --------
(no Q: ------------------
WR,SP,OR,CV)
270.50 .00 Free Outfall (no Q: WR,SP,OR,CV)
271.00 .00 Free Outfall (no Q: WR,SP,OR,CV)
271.50 .00 Free Outfall (no Q: WR,SP,OR,CV)
'
272.00 .00 Free Outfall (no Q: WR,SP,OR,CV)
272.50 .00 Free Outfalt (no Q: WR,SP,OR,CV)
273.00 .00 Free Outfall (no Q: WR,SP,OR,CV)
273.50 .00 Free Outfatl (no Q: WR,SP,OR,CV)
274.00 .00 Free Outfall (no Q: WR,SP,OR,CV)
274.50 .00 Free Outfalt (no Q: WR,SP,OR,CV)
275.00 .00 Free Outfall (no Q: WR,SP,OR,CV)
'
275.50 .10 Free Outfatl OR,CV (no Q: WR,SP)
276.00 .15 Free Outfall OR,CV (no Q: WR,SP)
276.50 .19 Free Outfall OR,CV (no Q: WR,SP)
277.00 .23 Free Outfalt OR,CV (no Q: WR,SP)
'
277.50 .25 Free Outfatl OR,CV (no Q: WR,SP)
278.00 .28 Free Outfatl OR,CV (no Q: WR,SP)
278.50 .30 Free Outfall OR,CV (no Q: WR,SP)
279.00 .32 Free Outfalt OR,CV (no Q: WR,SP)
'
279.50 .34 Free Outfall OR,CV (no Q: WR,SP)
280.00 13.69 Free Outfall SP,OR,C V (no Q: WR)
280.50 26.68 Free Outfalt SP,CV (no Q: WR,OR)
'
281.00 58.95 Free Outfall WR,SP,C V (no Q: OR)
281.50 117.56 Free Outfall WR,SP,C V (no Q: OR)
282.00
1 193.33 Free Outfall WR,SP,C V (no Q: OR)
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:32:14 Date: 07/14/2007

Type.... Pond Routing Summary Page 6.01 '
Name.... SED. BASIN 2 OUT Tag: 10-Yea Event: 10 yr
Fite.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 2 (Q10 ANALYSIS - 7-14-07).PPW '
Storm... TypeII 24hr Tag: 10-Yea
LEVEL POOL ROUTING SUMMARY
HYG Dir = R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\
Inflow HYG file = NONE STORED - SED. BASIN 2 IN 10-Yea
Outflow HYG file = NONE STORED - SED. BASIN 2 OUT 10-Yea
Pond Node Data = SED. BASIN 2
Pond Volume Data = POND 1
Pond Outlet Data = OUTLET
No Infiltration
INITIAL CONDITIONS
Starting WS Etev = 275.00 ft
Starting Volume = 1.056 ac-ft
Starting Outflow = .00 cfs
Starting Infiltr. _ .00 cfs
Starting Total Qout= .00 cfs
Time Increment = .0500 hrs
INFLOW/OUTFLOW HYDROGRAPH SUMMARY
Peak Inflow = 57.09 cfs at 11.9000 hrs
Peak
----- Outflow
------------- = 2.30 cfs at 13.7000 hrs

Peak
Elevation ------------
= 279.57 -----------------------
ft
Peak Storage = 3.208 ac-ft
MASS BALANCE
------------- (ac-ft)
-

+ Initial Vol ------------
= 1.056
+ HYG Vol IN = 3.157
- Infiltration = .000
- HYG Vol OUT = 2.768
- Retained Vol = 1.445
Unrouted Vol = -.000 ac-ft
(.001% of Inflow Volume)
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:32:14 Date: 07/14/2007

Appendix A
Index of Starting Page Numbers for ID Names
----- B -----
BASIN D.A. 10-Yea... 3.01
----- 0 -----
OUTLET... 5.01, 5.04
----- P -----
POND 1... 4.01
----- R -----
Raleigh... 2.01, 6.01
----- W -----
Watershed... 1.01
A-1
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:32:14 Date: 07/14/2007

' Job File: R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD
APARTMENTS - WET DETENTION BASIN 2 (Q100 ANALYSIS - 7-14-07).PPW
Rain Dir: C:\HAESTAD\PPKW\RAINFALL\
JOB TITLE
--------------------------
COLONIAL GRAND AT WAKEFIELD APARTMENTS
' WET DETENTION BASIN N0. 2
Q100 ROUTING CALCULATIONS
The following calculations are the routing calculations for the
Colonial Grand at Wakefield Apartments in Raleigh, North Carolina.
Wet Detention Basin Nos. 1 and 2 are designed to provide 85% TSS
removal as required by the NCDWQ and also to reduce the Q2 and Q10
' post-developed discharge to less than or equal to the Q2 and Q10
pre-developed discharge for each point of discharge as required by
the City of Raleigh. The basins are also designed to pass the
Q100 storm without overtopping the dam. The site stormwater
calculations were performed using the Rational Method. The
attached routing calculations were performed using the SCS
methodology. The SCS curve number was manipulated so that the
discharge for the respective storm will equal the discharge based
on the Rational Equation.
S/N: 621802506A84 Bass Nixon & Kennedy Inc
' PondPack Ver. 7.5 (786c) Compute Time: 10:38:11 Date: 07/14/2007

Table of Contents
Table of Contents
i
********************** MASTER SUMMARY *********************:
Watershed....... Master Network Summary ............. 1.01
****************** DESIGN STORMS SUMMARY *******************
Raleigh......... Design Storms ...................... 2.01
******************** RUNOFF HYDROGRAPHS ********************
BASIN D.A....... 100-Ye
SCS Unit Hyd. Summary .............. 3.01
************:********** POND VOLUMES ******s::**************
POND 1.......... Vol: Elev-Area ..................... 4.01
******************** OUTLET STRUCTURES *********************
OUTLET.......... Outlet Input Data .................. 5.01
Composite Rating Curve ............. 5.04
***:******************* POND ROUTING ********:************s*
SED. BASIN 2 OUT 100-Ye
Pond Routing Summary ............... 6.01
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:38:11 Date: 07/14/2007

~~,

Type.... Master Network Summary Page 1.01
Name.... Watershed
Fite.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 2 (Q100 ANALYSIS - 7-14-07).PPW
MASTER DESIGN STORM SUMMARY
Default Network Design Storm File, ID STORMS.RNQ Raleigh
Total
Depth Rainfall
Return Event in Type RNF File RNF
ID
-
------------
100-Ye ------
8.0000 ---
-----
Synthetic Cu ----
--------
rve SCSTYPES -
-----
----
TypeII 24hr
MAS TER NETWORK SUMMARY
SCS U nit Hydrogra ph Method
(*Node=Ou tfatl; +Node =Diversion;)
(Trun= HYG Truncation: Blank=None; L=Left; R=Rt; LR=Left&Rt)
Max
Return HYG Vot Qpeak Qpeak Max WSEL Pond
Storage
Node
------ ID
----------- Type Event
---- ------ ac-ft
---------- Trun hrs
-- --------- cfs ft ac-ft
-------- -------- ---------
BASIN D.A. AREA 100 4.247 11.9000 76.80
*DISCH ARGE PT 3 JCT 100 3.869 12.4500 8.48
SED. BASIN 2 IN POND 100 4.247 11.9000 76.80
SED. BASIN 2 OUT POND 100 3.869 12.4500 8.48 279.80
3.343
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:38:11 Date: 07/14/2007

Type.... Design Storms
Name.... Raleigh
File.... C:\HAESTAD\PPKW\RAINFALL\STORMS.RNQ
Title... COLONIAL GRAND AT WAKEFIELD APARTMENTS
WET DETENTION BASIN N0. 2
Q100 ROUTING CALCULATIONS
The following calculations are the routing
calculations for the Colonial Grand at Wakefield
Apartments in Raleigh, North Carolina. Wet Detention
Basin Nos. 1 and 2 are designed to provide 85% TSS
removal as required by the NCDWQ and also to reduce
the Q2 and Q10 post-developed discharge to less than
or equal to the Q2 and Q10 pre-developed discharge
for each point of discharge as required by the City
of Raleigh. The basins are also designed to pass the
Q100 storm without overtopping the dam. The site
stormwater calculations were performed using the
Rational Method. The attached routing calculations
were performed using the SCS methodology. The SCS
curve number was manipulated so that the discharge
for the respective storm will equal the discharge
based on the Rational Equation.
DESIGN STORMS SUMMARY
Design Storm Fite,ID = STORMS.RNQ Raleigh
Storm Tag Name = 100-Ye
Page 2.01
Data Type, File, ID = Synthetic Storm SCSTYPES.RNF TypeII 24hr
Storm Frequency = 100 yr
Total Rainfall Depth= 8.0000 in
Duration Multiplier = 1
Resulting Duration = 24.0000 hrs
Resulting Start Time= .0000 hrs Step= .1000 hrs End= 24.0000 hrs
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:38:11 Date: 07/14/2007

' Type.... SCS Unit Hyd. Summary Page 3.01
Name.... BASIN D.A. Tag: 100-Ye Event: 100 yr
' File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 2 (Q100 ANALYSIS - 7-14-07).PPW
Storm... TypeII 24hr Tag: 100-Ye
' SCS UNIT HYDROGRAPH METHOD
STORM EVENT: 100 year storm
Duration = 24.0000 hrs Rain Depth = 8.0000 in
' Rain Dir = C:\HAESTAD\PPKW\RAINFALL\
Rain File -ID = SCSTYPES.RNF - TypeII 24hr
Unit Hyd Type = Default Curvilinear
1 HYG Dir = R~\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL
CALCS\
HYG File - ID = BASIN D.A. 100 Ye
Tc (Min. Tc) _ .0833 hrs
' Drainage Area = 11.300 acres Runoff CN= 70
Computational Time Increment = .01111 hrs
' Computed Peak Time 11.9175 hrs
Computed Peak Flow 79.94 cfs
' Time Increment for HYG File .0500 hrs
Peak Time, Interpolated Output = 11.9000 hrs
Peak Flow, Interpolated Output 76.80 cfs
' DRAINAGE AREA
-------------------
ID:None Selected
' CN = 70
Area = 11.300 acres
S = 4.2045 in
' 0.25 = .8409 in
Cumulative Runoff
-------------------
4.5102 in
4.247 ac-ft
HYG Volume... 4.247 ac-ft (area under HYG curve)
' ***** UNIT HYDROGRAPH PARAMETERS *****
' Time Concentration, Tc = .08330 hrs (ID: None Selected)
Computational Incr, Tm = .01111 hrs = 0.20000 Tp
Unit Hyd. Shape Factor = 483.432 (37.46% under rising limb)
' K = 483.43/645.333, K = .7491 (also, K = 2/(1+(Tr/Tp))
Receding/Rising, Tr/Tp = 1.6698 (solved from K = .7491)
Unit peak, qp = 153.70 cfs
Unit peak time Tp = .05553 hrs
Unit receding limb, Tr = .22213 hrs
Total unit time, Tb = .27767 hrs
S/N: 621802506A84 Bass Nixon & Kennedy Inc
' PondPack Ver. 7.5 (786c) Compute Time: 10:38:11 Date: 07/14/2007

Type.... Vol: Etev-Area Page 4.01 '
Name.... POND 1
File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS,
- WET DETENTION BASIN 2 (Q100 ANALYSIS - 7-14-07).PPW
Title... Wet Detention Basin No. 2
Elevation Planimeter Area Al+A2+sgr(A1*A2) Volume Volume Sum
(ft) (sq.in) (acres)
-------
- (acres)
---------------- (ac-ft)
---------- (ac-ft)
-------------
-----------
270.00 -------------
-
----- .1037 .0000 .000 .000
272.00 ----- .1584 .3903 .260 .260
274.00 ----- .3106 .6908 .461 .721
276.00 ----- .4158 1.0858 .724 1.445
278.00 ----- .5019 1.3745 .916 2.361
280.00 ----- .5971 1.6464 1.098 3.459
282.00 ----- .7101 1.9584 1.306 4.764
POND VOLUME EQUATIONS
* Incremental volume computed by the Conic Method for Reservoir Volumes.
Volume = (1/3) * (EL2-EL1) * (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 EL1 and EL2
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:38:11 Date: 07/14/2007

Type.... Outlet Input Data Page 5.01
Name.... OUTLET
Fite.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 2 (Q100 ANALYSIS - 7-14-07).PPW
REQUESTED POND WS ELEVATIONS:
Min. Elev.= 270.00 ft
Increment = .50 ft
Max. Elev.= 282.00 ft
OUTLET CONNECTIVITY
---> Forward Flow Only (Upstream to DnStream)
<--- Reverse Ftow Only (DnStream to Upstream)
<---> Forward and Reverse Both Allowed
Structure No. Outfall E1, ft E2, ft
----------------- ---- ------- --------- ---------
Weir-Rectangular WR ---> TW 280.500 282.000
Stand Pipe SP ---> CV 279.500 282.000
Orifice-Circular OR ---> CV 275.000 282.000
Culvert-Circular CV ---> TW 269.500 282.000
TW SETUP, DS Channel
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:38:11 Date: 07/14/2007

Type.... Outlet Input Data Page 5.02 '
Name.... OUTLET
File.... R:\2006JOBS\06678000\C ALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS

- WET DETENTION BASIN 2 (Q100 ANALYSIS - 7-14-07).PPW '
OUTLET STRUCTURE INPUT DATA '
Structure ID = WR ,
Structure Type
----------------- = Weir-Rectangular
---------------

# of Openings
Crest Etev. ----
= 1
= 280.50 ft
'
Weir Length = 30.00 ft
Weir Coeff. = 3.000000
W
i
TW
ff
t U
d '
e
r
e
ec
s (
se a
justment equation)

Structure ID = SP
Structure Type--- -=-Stand-Pipe- '
# of Openings = 1
Invert Elev. = 279.50 ft
Diameter = 4.0000 ft '
Orifice Area = 12.5664 sq.ft
Orifice Coeff. _ .600
Weir Length
Weir Coeff. = 12.57 ft
= 3.000 '
K, Submerged = .000
K, Reverse = 1.000
Kb,Barrel = .000000 (per ft of full flow)

Barrel Length
= .00 ft '
Mannings n = .0000

Structure ID = OR
Structure Type = Orifice-Circular '
# of Openings = 1
Invert Elev. = 275.00 ft
Diameter = .2080 ft

Orifice Coeff.
_ .600 '

S/N: 621802506A84
PondPack Ver. 7.5 (786c)
1
Bass Nixon & Kennedy Inc
Compute Time: 10:38:11 Date: 07/14/2007 '

Type.... Outlet Input Data Page 5.03
Name.... OUTLET
' File.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 2 (Q100 ANA LYSIS - 7-14-07).PPW
' OUTLET STRUCTURE INPUT DATA
Structure ID = CV
' Structure Type
--- = Culvert-Circular
--------------
No. Barrels -------------------
= 1
' Barrel Diameter 1.5000 ft
Upstream Invert 269.50 ft
Dnstream Invert = 264.00 ft
Horiz. Length 150.00 ft
' Barret Length 150.10 ft
Barrel Slope = .03667 ft/ft
' OUTLET CONTROL DATA...
Mannings n .0130
Ke = .5000 (forward entrance loss)
Kb .018213 (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) = 1.142
T2 ratio (HW/D) 1.288
'
_
Slope Factor -.500
Use unsubmerged inlet control Form 1 equ.
Use submerged inlet control Form 1 equ.
In transition zone between unsubmerged an
interpolate between flows at T1 & T2...
At T1 Elev = 271.21 ft ---> Flow =
At T2 Elev = 271.43 ft ---> Flow =
below T1 elev.
above T2 elev.
d submerged inlet control,
7.58 cfs
8.66 cfs
' Structure ID = TW
Structure Type = TW SETUP, DS Channel
t ------------------------------------
FREE OUTFACE CONDITIONS SPECIFIED
CONVERGENCE TOLERANCES...
' Maximum Iterations= 30
Min. TW tolerance = .O1 ft
Max. TW tolerance = .01 ft
' Min. HW tolerance .01 ft
Max. HW tolerance = .O1 ft
Min. Q tolerance .10 cfs
Max. Q tolerance = .10 cfs
S/N: 621802506A84 Bass Nixon & Kennedy Inc
' PondPack Ver. 7.5 (786c) Compute Time: 10:38:11 Date: 07/14/2007

S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:38:11 Date: 07/14/2007

Type.... Composite Rating Curve
Name.... OUTLET
Page 5.04
Fite.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 2 (Q100 ANALYSIS - 7-14-07).PPW
***** COMPOSITE OUTFLOW SUMMARY ****

1

1

WS Elev, Total Q Notes
-------- -------- ------ -- Converge ------- ------------------
Elev. Q TW El ev Error
ft cfs ft +/-ft Contrib uting Structures
--------
270.00 -------
.00 ------
Free -- -----
Outfall --------
(no Q: ------------------
WR,SP,OR,CV)
270.50 .00 Free Outfatl (no Q: WR,SP,OR,CV)
271.00 .00 Free Outfall (no Q: WR,SP,OR,CV)
271.50 .00 Free Outfall (no Q: WR,SP,OR,CV)
272.00 .00 Free Outfatl (no Q: WR,SP,OR,CV)
272.50 .00 Free Outfall (no Q: WR,SP,OR,CV)
273.00 .00 Free Outfall (no Q: WR,SP,OR,CV)
273.50 .00 Free Outfall (no Q: WR,SP,OR,CV)
274.00 .00 Free Outfalt (no Q: WR,SP,OR,CV)
274.50 .00 Free Outfall (no Q: WR,SP,OR,CV)
275.00 .00 Free Outfall (no Q: WR,SP,OR,CV)
275.50 .10 Free Outfall OR,CV (no Q: WR,SP)
276.00 .15 Free Outfall OR,CV (no Q: WR,SP)
276.50 .19 Free Outfalt OR,CV (no Q: WR,SP)
277.00 .23 Free Outfalt OR,CV (no Q: WR,SP)
277.50 .25 Free Outfalt OR,CV (no Q: WR,SP)
278.00 .28 Free Outfalt OR,CV (no Q: WR,SP)
278.50 .30 Free Outfalt OR,CV (no Q: WR,SP)
279.00 .32 Free Outfalt OR,CV (no Q: WR,SP)
279.50 .34 Free Outfall OR,CV (no Q: WR,SP)
280.00 13.69 Free Outfall SP,OR,C V (no Q: WR)
280.50 26.68 Free Outfall SP,CV (no Q: WR,OR)
281.00 58.95 Free Outfall WR,SP,C V (no Q: OR)
281.50 117.56 Free Outfall WR,SP,C V (no Q: OR)
282.00 193.33 Free Outfatl WR,SP,C V (no Q: OR)
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:38:11 Date: 07/14/2007

Type.... Pond Routing Summary Page 6.01 '
Name.... SED. BASIN 2 OUT Tag: 100-Ye Event: 100 yr
Fite.... R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\WAKEFIELD APARTMENTS
- WET DETENTION BASIN 2
T
II 24hr
St (Q100 ANALYSIS - 7-14-07).PPW
Ta
: 100-Ye '
orm... ype g
LEVEL POOL ROUTING SUMMARY
HYG Dir = R:\2006JOBS\06678000\CALCULATIONS\PONDPACK\RATIONAL CALCS\
Inflow HYG file = NONE STORED - SED. BASIN 2 IN 100-Ye
Outflow HYG file = NONE STORED - SED. BASIN 2 OUT 100-Ye
Pond Node Data = SED. BASIN 2
Pond Volume Data = POND 1
Pond Outlet Data = OUTLET
No Infiltration
INITIAL CONDITIONS
Starting WS Elev = 275.00 ft
Starting Volume = 1.056 ac-ft
Starting Outflow = .00 cfs
Starting Infiltr. _ .00 cfs
Starting Total Qout= .00 cfs
Time Increment = .0500 hrs
INFLOW/OUTFLOW HYDROGRAPH SUMMARY
Peak Inflow = 76.80 cfs at 11.9000 hrs
Peak Outflow = 8.48 cfs at 12.4500 hrs
-----
Peak --------------
Elevation = -----------
279.80 -----------------------
ft
Peak
-----
----- Storage =
--------------
-------------- 3.343
-----------
----------- ac-ft
-----------------------
-----------------------
MASS BALANCE
------------- (ac-ft)
-------------
+ Initial Vol = 1.056
+ HYG Vol IN = 4.247
- Infiltration = .000
- HYG Vol OUT = 3.869
- Retained Vol = 1.434
Unrouted Vol = -.000 ac-ft
(.008% of Inflow Volume)
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:38:11 Date: 07/14/2007

Appendix A
Index of Starting Page Numbers for ID Names
----- B -----
BASIN D.A. 100-Ye... 3.01
----- 0 -----
OUTLET... 5.01, 5.04
----- P -----
POND 1... 4.01
----- R -----
Raleigh... 2.01, 6.01
----- W -----
Watershed... 1.01
A-1
S/N: 621802506A84 Bass Nixon & Kennedy Inc
PondPack Ver. 7.5 (786c) Compute Time: 10:38:11 Date: 07/14/2007