20080016 Ver 1_Stormwater Plans_20080509

CIVIL CONSULTANTS INC.
Civil Engineers
Land Development Consultants
To: DWQ
2321 Crabree Blvd
Suite 250
Raleigh, NC 27604
WE ARE SENDING YOU THE FOLLOWING ITEMS VIA
08-OoIto
Date: 5-8-08 Job No: 13037
Attn: Cyndi Karoly
Re: OC Animal Services
UPS Ground
Copies Date No. Description
1 4/30/08 CO-D9 Revised Site Plans
1 5-6-08 Letter by Town of Chapel HIll Approval
1 4/28/08 Storm Drainage Pipe Calcs.
1 4/25/08 Stormwater & Resource Conservation District Reports
REMARKS:
Qg??WMC p
MAY 9 2008
DENR - WATER QUALITY
COPY TO: FILE WETLANDS AND STORMWATER 8RAKA
Jim Compton - reviaed shee*& as -p1am a,t i
SIGNED: Rrianne M Macsev
LETTER OF TRANSMITTAL
3708 Lyckan Parkway . Suite 201 Durham, N.C. 27707
919-490-1645 Phone . [phone] Fax www.civil-consultants.com

May 6, 2008
Tony Whitaker
Civil Consultants, Inc.
3708 Lyckan Parkway
Suite 201
Durham, NC 27707
PLANNING
Town of Chapel Hill
405 Martin Luther King Jr. Blvd.
Chapel Hill, NC 27514
pboac [phone] fax[phone]
www.townofchapcffiM.org
Subject: Orange County Animal Services Facility - Final Plans/Zoning Compliance Permit
(File No. 9870-77-4584)
Dear Tony:
Town staff has reviewed the above application and finds *the development proposed therein to be
in general compliance with the Land Use Management Ordinance. I hereby approve the above
application for a Zoning Compliance Permit for the Orange County Animal Services Facility,
identified as Orange County Property Identifier Number 9870-77-4584. The application is
approved in accordance with approved plans, dated January 22, 2007, and revised April 30,
2008, June 8, 2007, August 15, 2007, August 29, 2007, January 22, 2008, and February 5, 2008
on file in the Planning Department and subject to the conditions listed on the attached Permit.
The work authorized by this permit will not be allowed to deviate from approved plans. If you
wish to revise the approved plans, you must first submit and have approved an application for
Modification of Zoning Compliance Permit, which includes the proposed revisions. If you have
not started the construction authorized by this approval within twelve (12) months of this
expiration date, the approval shall automatically expire and any permit issued pursuant to the
approval shall be void. Should you have questions, please call the Planning Department and ask
for me at 919-968-2728.
Sincerely,
Judy Johnso
b&'k4?
Senior Planner
cc: Bobby Pettiford, Town of Chapel Hill Inspection
Sue Burke, Town of Chapel Hill Engineering
Mike Taylor, Town of Chapel Hill Engineering
Curtis Brooks, Town of Chapel Hill Public Works
Matt Lawrence, Town of Chapel Hill Fire
Grant Gayle, Orange County Solid Waste
Gene Poveromo, Town of Chapel Hill Planning
Ellen Weinstein
Pam Jones, Orange County
Ted Be. lakOWASA

PLANNING
• • Town of Chapel Hill
405 Martin Luther King Jr. Blvd.
Chapel Hill, NC 27514
pboxe [phone] fax [phone]
www.townofchapelhill.org
THIS CERTIFIES THAT A
ZONING COMPLIANCE PERMIT FOR THE CONSTRUCTION OF THE ORANGE
COUNTY ANIMAL SERVICES FACILITY HAS BEEN ISSUED TO
Name of Applicant: Tony Whitaker Civil Consultants; Inc.
ty
Name of Development: Orange County Animal Services Facili
For: Construction of a 24,000 square foot building for the Orange County Animal Services
Facility in accordance with approved plans dated January 22, 2007, and revised April 30,
2008, June 8 2007, August 15, 2007, August 29, 2007, January 22, 2008, and February 5,
2008, on file in the Planning Department.
Location: 1601 Eubanks Road, Chapel Hill and identified as Orange County Property
Identifier Number 9870-77-4584
Conditions Prior to Bel:innine Site Work:
1. That the applicant shall obtain all necessary permits from the Town of Chapel Hill Building
Inspections Department.
2. That the applicant shall hold a pre-construction meeting with the Town's Landscape..
Architect, the Orange County Solid Waste Management, and Orange County Erosion Control
to review landscape protection procedures and construction waste management and recycling
respectively.
3. That the applicant shall post a construction sign that lists the property owner's representative
and telephone number, the contractor's representative and telephone number, and a telephone
number for regulatory information at the time of issuance of a Building Permit, prior to the
commencement of any land disturbing activities.
Miscellaneous Conditions
4. That prior to any street or lane closing, a traffic control plan shall be submitted to the Town
of Chapel Hill Engineering Department for review and approval.
5. That the applicant shall source separate construction debris.
6. During the construction phase, additional erosion and sediment controls may be required if
the proposed measures do not contain the sediment. Sediment leaving the property is a
violation of the Town's Erosion and Sediment Control Ordinance.
Conditions Prior to Occupancy
7. Prior to issuance of a Certificate of Occupancy, all of the documents enumerated below must
be submitted to the Town Stormwater Management Engineer for review and approval. After
reviewing and approving the documents, the Town Stormwater Management Engineer or
designee will issue an Approval Notification to the Town's Inspections Department.
a. A copy of the final plat or easement exhibit, signed and sealed by a North Carolina-
registered Land Surveyor and recorded by the County Register of Deeds, showing the
"Reserved Stormwater Facility Easement(s)", the stormwater management
facility(ies), and the maintenance access locations. The following notes must be
included on the recorded final plat or easement exhibit.
All engineered stormwater management control, treatment, and conveyance
structures located on or below the ground shall be wholly contained within an
easement entitled: "Reserved Stormwater Facility Easement Hereby Dedicated"
and shall be reserved from any development which would obstruct or constrict
the effective management, control, and conveyance of stormwater from or across
the property, other than the approved design and operation functions.
• Unless specifically designated as being "Public" and accepted by the Town of
Chapel Hill, the Reserved Stormwater Facility Easement(s) and the facilities
it/they protect are considered to be private, with the sole responsibility of the
owner to provide for all required maintenance and operations as approved by the
Town Manager.
• The Reserved Stormwater Facility Easement and the Operations and
Maintenance Plan are binding on the owner, heirs, successors, and assigns.
b. A copy of the recorded maintenance covenant ("Operations and Maintenance Plan"),
signed by the owner and recorded by the County Register of Deeds, for the stormwater
management facility(ics).
c. Certified as-built plans, signed and sealed by a North Carolina-registered Professional
Land Surveyor, showing building footprints, driveways, and all other impervious
surfaces as well as stormwater drainage/conveyance piping and stormwater
management structures. The as-built plans should be in DXF binary format using
State plane coordinates and NAVD 88.
d. Certification, signed and sealed by a North Carolina-registered Professional Engineer,
that the stormwater management facility(ies) was/were constructed in accordance with
the approved plans and specifications.
8. This stormwater approval limits the amount of total impervious area to 78,000 square feet as
reported in the SWIS submitted for the Zoning Compliance Permit. Any increase of
impervious area that occurs as a result of construction over this permitted amount shall
require a revised stormwater management report and plan, signed and sealed by a North
Carolina-registered Professional Engineer, be submitted to the Town Stormwater Engineer
for review and approval prior to the issuance of the C/O.
9. Please provide a stand-alone Operation and Maintenance Plan for the stormwater
management facilities. The O&M Plan shall be detailed, clear, and concise such that the

property owner (lay person) understands the O&M requirements (what, when, where, and
how) and can effectively implement them. The plan shall include:
• a statement for owner's signature acknowledging financial responsibility for
stormwater management facility.
• a brief discussion of the stormwater facility components, operation, and general
maintenance requirements.
• a detailed maintenance checklist and schedule for use by the owner(s) in
performing O&M - recommend in table-format that includes fields such as
maintenance items, maintenance frequency, observations, action, date, initials of
person performing inspection / maintenance.
10. The stormwater management facility(ies) shall be maintained 'by the property owner in
accordance with the recorded Operations and Maintenance Plan.
11. The owner shall be required to replace any failing stormwater management structures.
12. The owner may be liable if adjoining properties or rights-of-way receive substantial damage
associated with the discharge of stormwater from this property.
13. That approval of the final sewer plans and all improvements required for the OWASA sewer
main extension project, as designed to provide sewer service to this site and adjoining
properties, be approved by OWASA and the Town Manager prior to occupying the building.
Revicwed/Approved: Administration X . Date: May 6.2008
Town Council X Date: September 10, 2007
Issued By: .
CIVIL CONSULTANTS Nc.
Civil Engineers
Land Development Consultants
ORANGE COUNTY ANIMAL SERVICES
D8-ooIc'
STORM DRAINAGE PIPE CALCULATIONS
November 20, 2007
December 6, 2007
January 31, 2008
Revised April 28, 2008
Project #13037
Prepared for:
Orange County
P.O. Box 8181
Hillsborough, NC 27278
R O /
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2008
NDSAR WA ?MWA 7Y
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man
3708 Lyckan Park,vtiy . Suite 201 . Durham, N.C. 27707
919-490-1645 Prir t! . 919-403 0336 Fax . www.civil-consultants.com
PROJECT NARRATIVE
Project Name: Orange County Animal Services
Project Number: 13037
Report Date: January 31, 2008
Project Location: Southwest of the intersection of Eubanks Rd. and Millhouse
Rd.
Purpose: Storm drainage system.
Site Description:
The proposed development is a facility for Orange County Animal Services. The
existing site is located southwest of the intersection of Eubanks Rd. and
Millhouse Rd. The site is mainly brush with substantial trees along the western
side. There one streams that receives stormwater runoff from the project site.
The site currently drains to a stream that flows to Old Field Creek.
Proposed Development:
The proposed development will consist of 24,000+/- SF office, educational,
veterinary, and animal shelter space.
Storm Drainage Analysis:
The majority of the proposed project will be collected in a traditional drainage
system that will drain to new biofiltration and dry detention pond areas. A small
area will bypass the biofiltration/pond area and will be collected at the driveway
entrance in the proposed conventional pipe system along Eubanks Rd.
The runoff coefficient was also evaluated per drainage area and a conservative
inlet time of 5 minutes was used for most inlets. The time of concentration for
structures A05 and A07 were calculated based on the TR55 Method, and can be
found in the attachments.
All storm drainage calculations were prepared in accordance with the Town of
Chapel Hill.
2
Calculations:
Description Page
Storm Drainage: Schedule 4
Worksheets: Rational Coefficients 5
TR55 Flowpath 1 7
TR55 Flowpath 2 8
TR55 figure 3-1 9
Pipe Design Worksheets: Hydroflow Plan View (A) 10
Hydroflow Storm Sewer 10yr Summary (A) 11
Hydroflow Storm Sewer 25yr Summary (A) 12
Hydroflow 2 yr. Inlet Report (A) 13
Hydroflow Plan View (131) 14
Hydroflow Storm Sewer 10yr Summary (B1) 15
Hydroflow Storm Sewer 25yr Summary (61) 16
Hydroflow Plan View (62) 17
Hydroflow Storm Sewer 10yr Summary (62) 18
Hydroflow Storm Sewer 25yr Summary (62) 19
Storm Drainage Exhibit: EX1
STORM DRAINAGE STRUCTURE SCHEDULE
STRUCTURE DATA PIPE DATA
Structure
Number
Structure Type
Rim/Top Invert In
North Invert In
East Invert In
South Invert In
West
Invert Out
To Pipe
Length Out Pipe
Slope Pipe
Diameter Pipe
Material
# elev elev elev elev elev elev ft % in
A00 FES 475.80 NA 473.00 NA NA NA OUTFALL NA NA 24 RCP
A01 * NCDOT STD. 840.01 478.00 NA 473.39 NA NA 473.29 A00 29 1.00 24 RCP
A02 NCDOT STD. 840.01 479.75 NA 474.47 NA NA 474.37 A01 98 1.00 24 RCP
A03 NCDOT STD. 840.01 479.75 474.83 NA 474.83 NA 474.73 A02 26 1.00 24 RCP
A04 NCDOT STD. 840.01 479.76 NA 475.35 NA NA 475.25 A03 42 1.00 24 RCP
A05 NCDOT STD. 840.15 487.50 NA 484.00 NA NA 483.29 A04 265 3.00 24 RCP
A06 RISER 488.00 NA NA NA NA 484.00 A03 83 15.17 24 RCP
A07 PIPE END 492.00 NA NA NA NA 490.50 A05 43 10.96 15 RCP
B01 FES NA NA NA 490.33 NA NA OUTFALL NA NA 15 RCP
B02 NCDOT STD. 840.01 494.25 NA NA 490.73 NA 490.63 B01 30 1.00 15 RCP
B03 NCDOT STD. 840.01 494.50 NA NA 491.24 NA 491.14 B02 41 1.00 15 RCP
B04 NCDOT STD. 840.15 497.80 NA NA 493.10 NA 493.00 B03 117 1.50 15 RCP
B05 NCDOT STD. 840.15 496.80 NA NA NA NA 493.73 B04 59 1.00 15 RCP
B06 FES NA NA NA 486.00 NA NA OUTFALL NA NA 24 RCP
607 NCDOT STD. 840.15 491.00 NA NA NA NA 486.30 B06 30 1.00 24 RCP
B08 FES NA NA NA 490.33 NA NA OUTFALL NA NA 24 RCP
B09 NCDOT STD. 840.01 495.20 NA NA 491.13 NA 490.93 B08 40 1.50 24 RCP
B10 NCDOT STD. 840.01 496.70 NA NA 492.20 NA 492.10 B09 65 1.50 24 RCP
611 NCDOT STD. 840.15 496.50 NA NA 493.57 NA 493.47 B10 127 1.00 15 RCP
B12 FES 495.95 NA NA NA NA 494.70 611 113 1.00 15 RCP
Footnotes
FOR CURB INLETS, ELEVATION SHOWN AS RIM/TOC IS FOR TOP BACK OF CURB.
FOR CATCH BASINS, ELEVATION SHOWN AS RIM/TOC IS FOR TOP OF GRATE.
FOR JUNCTION BOXES, ELEVATION SHOWN AS RIM/TOC IS FOR TOP OF LID.
''i FOR YARD INLETS, ELEVATION SHOWN AS RIM/TOC IS FOR FLOW LINE.
RATIONAL COEFFICIENT
DRAINAGE BASIN AREA C A* C WEIGHTED C
SF
A01 6529 0.95 6202.55
3361 0.3 1008.3
9890 0.73
A02 1068 0.95 1014.6
1667 0.3 500.1
2735 0.55
A03 5094 0.95 4839.3
6427 0.3 1928.1
11521 0.59
A04 5944 0.95 5646.8
11337 0.3 3401.1
17281 0.52
A05 126890 0.35 44411.5
126890 0.35
A07 65844 0.4 26337.6
65844 0.40
B02 6077 0.95 5773.15
1652 0.3 495.6
7729 0.81
B03 5011 0.95 4760.45
9610 0.3 2883
14621 0.52
B04 4730 0.95 4493.5
0 0.3 0
4730 0.95
B05 0 0.95 0
21602 0.35 7560.7
21602 0.35
B07 160112 0.85 136095.2
0.3 0
160112 0.85
609 12877 0.95 12233.15
6561 0.22 1443.42
19438 0.70
RATIONAL COEFFICIENT
DRAINAGE BASIN AREA C W C WEIGHTED C
SF
B10 4717 0.95 4481.15
23894 0.85 20309.9
1031 0.35 360.85
29642 0.85
611 1553 0.95 1475.35
3687 0.3 1106.1
5240 0.49
B12 3627 0.95 3445.65
53482 0.3 16044.6
57109 0.34

TR 55 Time of Concentration Worksheet
Project Orange County Animal Services
Location Chapel Hill, North Carolina
Calculated By BMM
Checked By BMM
Date 12/5/2007
Revised
Sheet Flow
Segment 11
1 Surface Description
2 Mannings Roughness, n (table 3-1)
3 Flow Length, L in ft (max 300')
4 Two-year 24-hr rainfall, P2 in inches
5 Land Slope, s in ft/ft
6 Tt = 0.007x(nL)^0.8/(P2^0.5xs^0.4) in hr
Shallow Concentrated Flow
Segment K
7 Surface description (paved or unpaved)
8 Flow length, L in ft
9 Watercourse slope, s in ft/ft
10 Average velocity, V in ft/s (figure 3-1)
11 Tt=U3600V in hr
Channel Flow
Segment IC
12 Cross Sectional flow area, a in ft^2
13 Wetted perimeter, pw in ft
14 Hydraulic radius, r=a/pw in ft
15 Channel slope, s in ft/ft
16 Manning's roughness, n
17 V=1.49xr^0.667xs"0.5/n in ft/s
18 Flow length, L in ft
19 Tt=U3600V, in hr
20 Watershed total Tc in hours
Rainfall Intensity
21 Time of Concentration, Tc in minutes
Pre-development Condition Post-development Condition

Subtotal Subtotal

0.000 0.000

i EF
unpaved
271
0.023
2.6
0.196 0.196 0.000

DE FG CD
5 5 5
8 8 8
0.63 0.63 0.63
0.03 0.003 0.033
0.35 0.35 0.35
0.54 0.16 0.57
742 199 550
0.382 0.353 0.736 0.270 0.270
0.93 0.27

55.89 16.21
1 OF 1 Flowpath 1 OF tr551.xis 12/6/2007
TR 55 Time of Concentration Worksheet
Project Orange County Animal Services
Location Chapel Hill, North Carolina
Calculated By BMM
Checked By BMM
Date 12/5/2007
Revised
Sheet Flow
Segment 1[
1 Surface Description
2 Mannings Roughness, n (table 3-1)
3 Flow Length, L in ft (max 300')
4 Two-year 24-hr rainfall, P2 in inches
5 Land Slope, s in ft/ft
6 Tt = 0.007x(nQA0.8/(P2^0.5xs^0.4) in hr
Shallow Concentrated Flow
Segment IC
7 Surface description (paved or unpaved)
8 Flow length, L in ft
9 Watercourse slope, s in ft/ft
10 Average velocity, V in ft/s (figure 3-1)
11 Tt=U3600V in hr
Channel Flow
Segment IC
12 Cross Sectional flow area, a in ft^2
13 Wetted perimeter, pw in ft
14 Hydraulic radius, r=a/pw in ft
15 Channel slope, s in ft/ft
16 Manning's roughness, n
17 V=1.49xr^0.667xs^0.5/n in ft/s
18 Flow length, L in ft
19 Tt=U3600V, in hr
20 Watershed total Tc in hours
Rainfall Intensity
21 Time of Concentration, Tc in minutes
Pre-development Condition Post-development Condition

? AB Subtotal AB BC Subtotal
Lawn Lawn
0.24 0.24
139 139
3.6 3.6
0.050 0.050
0.202 0.202 0.202 0.202

0.000 0.000

BC CD
5 5
8 8
0.63 0.63
0.033 0.033
0.35 0.35
0.57 0.57
998 998
0.490 0.490 0.490 0.490
0.69 0.69

41.56 41.56
1 OF 1 Flowpath 1OF tr552.x1s 12/6/2007
Chapter 3
Time of Concentration and Travel Time Technical Release 55
Urban Hydrology for Small Watersheds
Figure 3-1 Average velocities for estimating travel time for shallow concentrated flow
.50
.20
.10

0
CL
0
m .06
IA
0
V
m .04
3
.02
.01
.005
1 2 4 6 10 20
Average velocity (ft/sec)
3-2 (210-VI-TR-66, Second Ed., June 1986)
q -
?_ _?__r1 _... I?1...? \/.e\?/
Hydraflow Storm Sewers 2003
Storm Sewer Summary Report Page 1
Storm Sewer Summary Report
Page 1
Line Line ID Flow Line Line Invert Invert Line HGL HGL Minor Dns
No. rate size length EL Dn EL Up slope down up loss line
(cfs) (in) (g) (ft) (ft) N (n) (g) (ft) No.
1 A01-A00 19.42 24 c 28.7 473.00 473.29 1.009 475.00 475.17 0.69
End
2 A02-A01 18.71 24 c 98.4 473.39 474.37 0.996 475.85* 476.53* 0.39
1
3 A03-A02 18.58 24 c 26.1 474.47 474.73 0.996 476.91 * 477.09* 0.60
2
4 A04-A03 8.22 24 c 41.8 474.83 475.25 1.004 477.69* 477.74* 0.12
3
5 A05-A04 7.54 24 c 264.8 475.35 483.29 2.998 477.86 484.26 0.19
4
6 A07-A05 2.85 15 c 42.9 484.00 490.50 15.166 484.46 491.18 0.28
5
7 A06-A03 9.51 18 c 61.0 474.88 484.00 14.951 477.69 485.18 0.64
3
Project File: SD A.stm Number of lines: 7 Run Date: 0428-2008
NOTES: c = circular; e = elliptical; b = box; Return period = 25 Yrs.; * Indicates surcharge condition.
Hydraflow Storm wars 2003
l2
Inlet Report
Page 1
Line Inlet ID Q = Q Q Q Junc Curb Inlet Grate Inlet Gutter Inlet Byp
line
No CIA carry capt byp type Ht L area L W So W SW Sx n depth spread depth spread Dep No
(cfs) (cfs) (cfs) (cfs) (in) (ft) (sgft) (ft) (ft) (ft/ft) (ft) (it/ft) (ft/ft) (ft) (ft) (ft) (ft) (in)
1 A01 0.97 0.00 0.97 0.00 Comb 6.0 4.00 0.00 1.00 2.00 0.010 2.00 0.100 0.030 0.013 0.24 3.33 0.25 2.88 2.00 Off
2 A02 0.19 0.00 0.19 0.00 Comb 6.0 4.00 0.00 1.00 2.00 0.045 2.00 0.100 0.030 0.013 0.10 1.00 0.10 0.92 2.00 1
3 A03 1.12 0.00 1.12 0.00 Comb 6.0 4.00 0.00 1.08 2.00 0.045 2.00 0.100 0.030 0.013 0.20 2.00 0.20 1.78 2.00 2
4 A04 1.20 0.00 1.20 0.00 Comb 6.0 4.00 0.00 0.89 2.00 0.017 2.00 0.100 0.030 0.013 0.24 3.33 0.25 2.71 2.00 3
5 A05 3.39 0.00 3.39 0.00 DrGrt 0.0 0.00 2.45 0.39 2.00 Sag 2.00 0.030 0.030 0.000 0.40 28.95 0.40 28.95 0.00 Off
6 A07 1.80 0.00 1.80 0.00 Hdwl 0.0 0.00 0.00 0.00 0.00 Sag 0.00 0.000 0.000 0.000 0.00 0.00 0.00 0.00 0.00 Off
7 A06 9.51' 0.00 9.51 0.00 DrCrb 6.0 12.00 0.00 0.00 0.00 Sag 0.00 0.030 0.030 0.000 0.41 13.66 0.41 13.66 0.00 Off
Project File: SD A.stm I-D-F File: chapel hill.IDF Number of lines: 7 Run Date: 0428-2008
NOTES: Inlet N-Values = 0.016; Intensity = 71.48 /(Inlet time + 13.00) ^ 0.87; Return period = 2 Yrs. ; * Indicates Known Q added
U,.,Ar?nfinw Plan Viaw
Hydraflow Storm Sewers 2003
IJ::?
Storm Sewer Summary Report Page,
Storm Sewer Summary Report
Page 1
Line Line ID Flow Line Line Invert Invert Line HGL HGL Minor Dns
No. rate size length EL Dn EL Up slope down up loss line
(cfs) (in) (ft) (ft) (ft) N (ft) (ft) (ft) No.
1 B02-601 4.57 15 c 30.5 490.33 490.63 0.984 491.19' 492.11 n/a
End
2 B03-1302 3.49 15 c 41.5 490.73 491.14 0.989 492.11 492.20 0.17
1
3 1304603 2.22 15 c 117.0 491.24 493.00 1.504 492.37 493.89 n/a
2
4 B05-1304 1.43 15 c 58.7 493.10 493.73 1.073 493.89 494.41 n/a
3
5 1307-1306 26.45 24 c 30.0 486.00 486.30 1.000 487.80' 490.16' n/a
End
Project File: SD B1.stm Number of lines: 5 Run Date: 12-06-2007
NOTES: c = circular; e = elliptical; b = box; Return period = 25 Yrs.; ' Indicates surcharge condition.
Hydraflow Storm Sewers 2003
1l0
Hvdraflow Plan View
Outfall
1
2
B10
B11
4
B12
Project file: SD B2.stm No. Lines: 4 12-06-2007
nyowa zwrm x - 4w
Storm Sewer Summary Report
Page 1
Line Line ID Flow Line Line Invert Invert Line HGL HGL Minor Dns
No. rate size length EL Dn EL Up slope down up loss line
(cfs) (in) (ft) (ft) (ft) N (ft) (ft) (ft) No.
1 1309-1308 9.35 24 c 39.8 490.33 490.93 1.507 491.41 492.64 n/a
End
2 B10-B09 7.36 24 c 64.7 491.13 492.10 1.499 492.64 493.56 n/a
1
3 1311-B10 3.51 15 c 127.1 492.20 493.47 1.000 493.56 494.69 n1a
2
4 B12-B11 3.19 15 c 112.8 493.57 494.70 1.002 494.69 495.84 n/a
3
Project File: SD B2.stm Number of lines: 4 Run Date: 12406-2007
NOTES: c = circular; e = elliptical; b = box; Return period = 10 Yrs.; ' Indicates surcharge condition.
Hydraflow Storm Sewers 2003
I°
Storm Sewer Summary Report
Page 7
Line Line ID Flow Line Line Invert Invert Line HGL HGL Minor Dns
No. rate size length EL Dn EL Up slope down up loss line
(cfs) (in) (ft) (ft) (ft) (%) (ft) (ft) (ft) No.
1 BO9-BOB 10.74 24 c 39.8 490.33 490.93 1.507 491.49 492.81 n/a
End
2 B10-B09 8.43 24 c 64.7 491.13 492.10 1.499 492.81 493.70 n/a
1
3 B11-610 4.00 15 c 127.1 492.20 493.47 1.000 493.70* 494.81* n/a
2
4 B12-B11 3.62 15 c 112.8 493.57 494.70 1.002 494.81 495.95 n/a
3
Project File: SD B2.stm Number of lines: 4 Run Date: 12-06-2007
NOTES: c = circular; e = elliptical; b = box; Return period = 25 Yrs.; * Indicates surcharge condition.
Hydraflow Storm Sewers 2003
19

CIVIL CONSMANTS
l l? ii i:r?in? rr?
Lind I ?cc?!,,??e?rnt t'ni,>ull,uu?
lbg- Co t LA
ORANGE COUNTY ANIMAL SERVICES
STORMWATER AND RESOURCE CONSERVATION DISTRICT
REPORTS
March 20, 2007
Revised May 7, 2007
Revised May 18, 2007
Revised November 15, 2007
Revised April 25, 2008
Project #13037
Prepared for:
Orange County
P.O. Box 8181
Hillsborough, NC 27278
15?N CARo','
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SEAL
• 10437
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S ?STT?ROU 2008
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TABLE OF CONTENTS
Number of page
Stormwater Impact Statement
Stormwater Management Plan
16
Development in the Resource Conservation District 97
STORMWATER IMPACT STATEMENT
FOR
ORANGE COUNTY ANIMAL SERVICES
tP- aet
STORMWATER IMPACT STATEMENT
Project Name: Orange County Animal Services
Project Number: 13037
Report Date: March 19, 2007, Revised May 7, 2007; May 18, 2007;
November 15, 2007; Revised April 25, 2008
Project Location: Eubanks Road, Chapel Hill, Orange County
Purpose: To assess the stormwater impacts of a proposed animal
services building
A. Site Analysis and Narrative
Land Use, Density, Impervious Cover and Phasing
The property is a tract which is currently undeveloped on the south side of
Eubanks Road (SR1727) just west of the crossing of State University Railroad
and Eubanks Road. Currently there is no development on the 5.95 acre tract
except for a gravel driveway (Genestu Drive) which is bordering the eastern edge
of the tract. The tract has frontage along Eubanks Road for approximately 500
feet. The proposed land use is for a public service facility to be owned by
Orange County for the purposes of building an animal services facility.
Construction is proposed of a main building of approximately 24,000 square feet
with associated parking lot, animal exercise area, and service area. The only
current impervious cover on the property is the existing gravel driveway, gravel in
limited locations within the railroad right-of-way, and pavement within the
Eubanks Road right-of-way. The proposed allocated impervious area for the
property is approximately 78,000 square feet.
Location, Topography, Drainage Conditions
As discussed above the site is located along the south side of Eubanks Road,
north of Chapel Hill. The land slopes from a high area just to the south of the site
falling at a slope of approx 4% to 6% toward an existing roadside drainageway
paralleling Eubanks Road. The drainageway along Eubanks Road flows westerly
into a perennial stream just west of the site. This perennial stream flows to the
north crossing under Eubanks Road and becomes tributary to Old Field Creek at
a location just north of Eubanks Road.
PI4
Upstream and/or Downstream Volumes, Discharges and Velocities
Analyses of stormwater flow rates and volumes were performed for the site (pre-
development and post-development conditions) using techniques from USDA
TR-55 and incorporating the Peak Discharge Method. Calculations were
performed for the 1-year, 2-year, and 25-year, 24-hour storm events. In keeping
with Chapel Hill requirements for release rate management, stormwater
detention will be provided that will control peak flow rates for those storm events
to not be increased above the pre-development rates.
Backwater Impacts and Effects on Drainage Conveyance Facilities
The drainage from off-site flowing on to the site from the high ground on the
south begins less than 100 feet off the site. The drainage from this area is not to
be impeded by the construction proposed to develop the site and therefore no
backwater effects are anticipated.
Ability of Natural Drainage Channel to Convey Additional Volumes,
Discharges and Velocities
The drainage way which is the roadside ditch along Eubanks Road will continue
to receive all the runoff from the site. The peak discharge rates from the
developed areas will be controlled by detention facilities for the 1-year, 2-year,
and 25-year storm events so that peak flow rates will not be increased. Since the
flow rates are not going to increase, the drainage way is not expected to be
adversely affected by the development proposed.
Potential Mitigation Measures
Due to the management measures proposed for controlling peak discharge rates
and stormwater quality, adverse impacts are not expected to occur to the surface
water system downstream of the site as a result of the development.
Delineation of Resource Conservation District (RCD), Jurisdictional
Wetlands, Soils Series and Flood Hazard Areas
The perennial stream that is flowing just to the west of the site and crosses under
Eubanks Road is a tributary to Old Field Creek. The three zones of the RCD
from this stream, (Stream Side Corridor, Managed Use Corridor and Upland
Corridor) are all present on the northwest corner of the site. This RCD limit is
also influenced by the stream from the opposite side of Eubanks Road. The
RCD zones are shown on the Site Plan drawings. Based on the wetlands
Paae3
evaluation report prepared by The Catena Group, October 5, 2007 (copy
attached), there are no wetlands present on the site. Soils on the site are mostly
of the Georgeville type with some small area of Tatum type (both are Hydrologic
Group B), based upon the Orange County Soils Survey. A review of Flood
Hazard Areas based on the published maps and the NC Floodplain Mapping
Information System indicate that the nearest flood hazard areas are on the
downstream areas that are on the opposite side of Eubanks Road from the site.
While not indicated on the flood maps, actual topographic survey data has found
small areas on the south side of Eubanks Road that are at an elevation such that
backwater effects are present at or near the northwest corner of the site. These
areas are so indicated on the plans.
B. PROPOSED STORMWATER MANAGEMENT PRACTICES
All of the roof top stormwater runoff will be directed to underground cistern(s) that
will have a volume of 24,000 gallons. Approximately 25% of the cistern(s)
storage will be kept available for stormwater runoff reuse by the animal services
facility. Roof top runoff that is not retained in the cistern(s) will flow to the
stormwater management system. Site stormwater will be collected and
conveyed to a series of two devices for treatment and control. The first device
will be a bioretention area. The bioretention area will provide treatment for the
stormwater runoff from small storm events and the initial runoff from larger storm
events. Some of the water passing through the filter portion of the bioretention
device will be infiltrated into the underlying soils with the remainder being
collected in an underdrain system. The underdrain system from the bioretention
area, along with the overflow of the ponding area due to larger storms, will flow to
a dry detention pond for peak flow control of the larger storm events. This dry
detention pond will also have an infiltration area in the bottom of the pond. From
the dry detention pond the flow will be discharged to the existing roadside
drainage system along Eubanks Road. Only a small amount of impervious area
(approx. 8,000 sq. ft.) which is to be created will be at elevations that are too low
to be captured in the system (the portion of the proposed driveway that is nearer
to Eubanks Road and a portion of the walking trails).
C. RELEASE RATE MANAGEMENT
Release rate analysis was performed using techniques from USDA TR-55 and
incorporating the Peak Discharge Method along with abstractions for the
detention volumes provided. As required by Chapel Hill, release rates will be
controlled for the 1-year, 2-year, and 25-year, 24-hour storm events. The
infiltration zones in the bioretention area and in the detention pond, as described
in Section B above, will provide for infiltration of the increase in flows from the 1-
year and 2-year storm events. The storage and orifice release of stormwater
???, LL
from the larger storms provided in the detention pond will control the release rate
from the 25-year storm.
D. VOLUME MANAGEMENT
Based upon Chapel Hill requirements, the increased volume from the 2-year, 24-
hour storm must be managed onsite. Additional runoff volume produced in the 2-
year, 24-hour storm event will be managed in the infiltration zones of the
bioretention area and of the detention pond and directed to the cistern(s) for
reuse as described in Section B above.
E. WATER QUALITY MANAGEMENT
Chapel Hill requires treatment of stormwater from impervious surfaces
associated with the development to achieve 85% removal of Total Suspended
Solids. This treatment will be accomplished by directing the runoff from the
impervious surfaces to the bioretention area. This device treats the runoff from
small storm events and the initial runoff of larger events for pollutant removal as
described in Section B above.
F. PRELIMINARY NUTRIENT LOADING CALCULATIONS
Nutrient loading calculations are provided to show the Nitrogen and Phosphorous
loading rates from the facility.
Nutrient Pre-Development Post-Development Post-Development
Loading Coefficient Loading Coefficient Loading
Total Phosphorous 0.08 Ibs/acre/ ear 1.6 Ibs/acre/ ear 9.52 Ibs/ ear
Total Nitrogen 0.6 Ibs/acre/ ear 8.8 Ibs/acre/ ear 52.36 Ibs/ ear
G. MAINTENANCE AND OPERATIONS PLAN
An Operation and Maintenance Plan is incorporated into the Stormwater
Management Plan as one of the attachments for both the bioretention area and
for the detention basin.

Attachments:
N.C. Floodplain Mapping Information System
FIRM Map; Panel No. 370342 0255 B, March 16, 1981
Nutrient Loading Calculations
Wetlands Evaluation: OC Animal Services Site, The Catena Group, October 5,
2007
Map Output
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Orange Co Animal Services
Wed Feb 28 10:01:36 EST 2007
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NATIONAL FLOOD INSURANCE PROGRAM
FIRM
FLOOD INSURANCE RATE MAP
ORANGE COUNTY,
NORTH CAROLINA
(UNINCORPORATED AREAS)
PANEL 255 OF 350
(SEE MAP INDEX FOR PANELS NOT PRINTED)
COMMUNITY-PANEL NUMBER
310342 0255 B
EFFECTIVE DATE:
MARCH 16, 1981
federal emergency management agency
federal insurance administration
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Nutrient Loading Calculation
Project: Orange County Animal Services
Location: Chapel Hill
Date: 3/12/2007
Rev: 3/12/2007
Site Area Nitrogen Total N Phosphorous Total P
Land Use Type Acres lbs/ac/ r lbs/ r lbs/ae/r lbs/ r
Low Density Residential 5.2 0.0 0.7 0.0
Hi Density Residential 7.4 0.0 1.2 0.0
Office/Institutional 5.95 8.8 52.36 1.6 9.52
Commercial 13.2 0.0 1.6 0.0
Industrial 11.2 0.0 1.4 0.0
Undeveloped/Forest/Open 0.6 0.0
J 0.08 0.0
Pasture 2.6 0.0 E 0.5 0.0
?av.
The
Catena
Group
410-B Millstone Drive
Hillsborough, NC 27278
[phone]
October 5, 2007
Tony Whitaker
Civil Consultants, Inc.
3708 Lyckan Parkway, Suite 201
Durham, NC 27707
Subject: Wetland Evaluation: OC Animal Services Site, Eubanks Road
Orange County, North Carolina
TCG Job # 2122
Dear Mr. Whitaker,
Per your request, The Catena Group (TCG) conducted a wetlands assessment in the vicinity of an
Unnamed Tributary (UT) to Old Field Creek on the OC Animal Service site south of Eubanks
Road (SR 1727) in Orange County, North Carolina.
Prior to field investigations, the United States Geologic Survey (USGS) topographic map (1978
Chapel Hill quadrangle) and 2003 aerial photography were examined to determine if any wetland
features were visually discernable (Figure 1 and 2). Wetlands were not identified on the
topographic map or the aerial photograph.
The field investigation was conducted on October 4, 2007, by Kate Montieth and Jenn Logan of
TCG. The project area was evaluated based on criteria established in the U.S. Army Corps of
Engineers (USACE) Wetland Delineation Manual (1987) and accompanying USACE Wetland
Determination Data Form. This form is based on the three parameter approach in which hydric
soils, hydrophytic vegetation, and hydrology, are evaluated to determine if an area is considered
a wetland.
Approximately 50 feet on either side of the stream and 100 feet from the road was searched for
wetland features. No wetlands were identified within the project area. A USACE Wetland
Determination Data Form was completed for the area which exhibited the most wetland
characteristics; however, the area was determined to be upland (Figure 2, Appendix A).
The findings presented herein represent The Catena Group's professional opinion based on our
site evaluation and knowledge of the current federal and state laws and rules governing
Jurisdictional Waters of the United States. No wetlands were identified within the area of
potential impact. Please let us know if you have any questions or concerns with the results of
this study.
Sincerely,
Kate Montieth
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The
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ena Wetland Assessment
Group 0 'SO _G'"J Feet
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Old Field Creek
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Data Form Point

UT to Old Field Creek

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Approximate Approximate Study Area Boundary

The OC Animal Services Site o(1„Ix!t 2007 Figure

Catena Wetland Assessment Ska?
Group
0I 25 { 1 0 Feet
Orange County, North Carolina Job No.
2122

_-i_1)
Appendix A
USACE Wetland Determination Data Form
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DATA FORM
ROUTINE WETLAND DETERMINATION
(1987 COE Wetlands Delineation Manual
Project/Site: OC Animal Services
Applicant/Owner.
Investigator(s) K. Montie J. Logan
Do Normal Circumstances exist on the site? es No
Is the site significantly disturbed (Atypical Situation)? es ®o
Is this area a potential Problem Area? Yes o
(If needed, explain on reverse)
Date: October 4, 2007
County: Orange
State: North Carolina
Community IE upland
TransectID:
Plot ID:
VEGETATION
Dominant Plant Species Stratum Indicator Dominant Plant Species Stratum Indicator
1. Microstegium vimineum grass - 9.
2. Ligustrum sinense shrub FAC 10.
3. Acer mbrum canopy FAC 11.
4. Liquidambarstyraci/lua canopy FAC+ 12.
5. Smilax roturrdifolia vine FAC 13.
6. Rubus al egheniensis vine UPL 14.
7. Solida o s p. herb - 15.
8. Polystic rum acrostichoides TeT FAC 16.
Percent of Dominant Species that are OBL, FACW, or FAC (excluding FAC-' 63%
Remarks:
HYDROLOGY
Recorded Data (Describe Remarks)
Stream, Lake, or tide Gauge
Aerial Photographs
Other
No Recorded Data Available Wetland Hydrology Indicators
Primary Indicators:
Inundated
_ Saturated in Upper 12 Inches
_ Water Marks
Drift Lines
_
_ Sediment Deposits
Field Observations: Drainage Patterns in Wetlands
Secondary Indicators (2 or more required):
Depth of Surface Water: none (in.) Oxidized Root Channels in Upper 12 Inches
Water-Stained Leaves
Depth to Free Water in Pit: none (in.) Local Soil Survey Data
FAC-Neutral Test
Depth to Saturated Soil: none (in.) -Other (Explain in Remarks)
Remarks No hydologic indicators.
--N__ . /l
SOILS
Map Unit Name
(Series and Phase): Geort;eville silt loam Drainage Class: well drained
Field Observations
Taxonomy (Subgroul Typic Kanhapludults Confirm Mapped Type? Yes
Profile Description:
Depth Matrix Color Mottle Colors Mottle Texture, Concretions,
inches Horizon (Munsell Moist) (Munsell Moist) Abundance/Contrast Structure, etc.
0-2 10YR 413 clay loam
2-8 5Y 416 2.5YR 514 few distinct clay loam
8+ 2.5YR 613 7.5YR 516 common prominent clay loam
Hydric Soil Indicators:
_ Histosol Concretions
Histic Epipedon High Organic Content in Surface Layer in Sandy Soils
Sulfidic Odor Organic Streaking in Sandy Soils
_Aquic Moisture Regime Listed on Local Hydric Soils List
Reducing Conditions Listed on National Hydric Soils List
_Gleyed or Low-Chroma Color Other (Explain in Remarks)
Remarks No hdric soil indicators
WETLAND DETERMINATION
Hydrophytic Vegetation Present?
Wetland Hydrology Present?
Hydric Soils Present?
Yes No
Yes RNo
Yes Is this Sampling Point Within a Wetland? Yes No

Remarks The point is not in a wetland

STORMWATER MANAGEMENT PLAN
FOR
ORANGE COUNTY ANIMAL SERVICES
-OnA 0 IL
STORMWATER MANAGEMENT PLAN
Project Name: Orange County Animal Services
Project Number: 13037
Report Date: March 14, 2007, revised May 7, 2007; May 18, 2007;
November 15, 2007; Revised April 25, 2008
Project Location: Eubanks Road, Chapel Hill, Orange County
Purpose: Management of stormwater for Proposed Animal Services
Building
Site Description:
The property is a tract which is currently undeveloped on the south side of
Eubanks Road (SR1727) just west of the crossing of State University Railroad
and Eubanks Road. Currently there is no development on the 5.95 acre tract
except for a gravel driveway (Genestu Drive) which is bordering the eastern edge
of the tract. The tract has frontage along Eubanks Road for approximately 500
feet. The only current impervious cover on the site is the existing gravel
driveway, gravel in limited locations within the railroad right-of-way, and
pavement within the Eubanks Road right-of-way. The site is located along the
south side of Eubanks Road, north of Chapel Hill.
Proposed Development:
The proposed land use is for a public service facility to be owned by Orange
County for the purposes of building an animal services facility. Construction is
proposed of a main building of approximately 24,000 square feet with associated
parking lot, animal exercise area, and service area. The only current
impervious cover on the property is the existing gravel driveway, gravel in limited
locations within the railroad right-of-way, and pavement within the Eubanks Road
right-of-way. The proposed allocated impervious area for the property is
approximately 78,000 square feet.
Existing and Proposed Storm Drainage System:
There is no existing storm drainage system, only a roadside ditch along Eubanks
Road. The site slopes from a high area just off site to the south of the site falling
at a rate of approx 4% to 6% toward existing roadside drainage ways paralleling
Eubanks road. The drainage way along Eubanks Road flows westerly into a
perennial stream just west of the site; this perennial stream crosses to the north
under Eubanks Road and becomes tributary to Old Field Creek at a location just
north of Eubanks Road.
Pnfe,11
Once developed with the buildings and the parking lot and driveway, the site will
have a stormwater collection system for the building and service area which will
flow through stormwater pipes to the parking area and thence to the stormwater
management BMP's/IMP's. The BMP's will infiltrate a portion of the stormwater
and the remainder will discharge into the roadside drainage way on the southside
of Eubanks Road.
Stormwater Detention Structure(s):
Stormwater from impervious areas will be treated through a Bioretention BMP
with infiltration of some of the stormwater though the bottom of the underdrain
section into the native soils (soils in the proposed stormwater management area
are all in the Georgeville group, Hydrologic Group B, based upon the Orange
County Soils Survey). The overflow from the ponding area and the underdrain
flow from the Bioretention BMP will discharge to a dry detention pond. The
detention pond will have an infiltration area in the bottom which will provide
infiltration of some of the stormwater. The detention pond outflow will discharge
to the existing roadside drainage way along Eubanks Road. The following table
summarizes the onsite impervious area allocations for preliminary design
purposes.
Proposed Bldg. Parking, etc. draining to
stormwater management system
Allowance for possible future expansion
BMP design impervious area
Proposed impervious area not captured by
stormwater management system
Impervious Area (sq. ft
63,384
+5,000
68,384
8,029
The existing impervious area of Genestu Drive is neither contributory to the
stormwater runoff for the project nor proposed to be modified; therefore, it has
not been included in the pre-develop me nt/post-development hydrologic
calculations.
BMP's/[MP's:
All of the roof top stormwater runoff will be directed to underground cistern(s) that
will have a volume of 24,000 gallons. Approximately 25% of the cistern(s)
storage will be kept available for stormwater runoff reuse by the animal services
facility. Roof top runoff that is not retained in the cistern(s) will flow to the
stormwater management system. Stormwater from the impervious areas of the
site will be discharged to a proposed bioretention device. The device will allow a
ponding depth of approximately 12 inches, with any overflow into a detention
pond. Underdrains from the bioretention BMP will discharge into the detention
pond as well. The detention pond will be used to control the peak flows from
large storm events with outflow through an orifice in the riser device. Both the
bioretention cell and the detention pond will have infiltration areas. This
infiltration will accommodate the additional
oo - ) 8
(post-development vs. pre-development) stormwater runoff that is expected to
occur from storm events up to the 2 yr, 24 hour event.
Grading/Landscaping:
Grading of the site will be employed to produce a building pad area for the
proposed building on the southern portion of the site. The parking area will be in
front of the building (between the building and Eubanks Road) and will be 2ft to 4
ft lower than the building. The entry driveway will curve around the west side of
the site from the parking area to Eubanks Road and will slope down to Eubanks
for about 12 feet in elevation. A sloped embankment will bring the grade down in
front of the parking area to the stormwater BMP devices. Landscape plans will
be produced to meet Chapel Hill's landscape requirements.
Erosion Control Features:
Erosion control plans were prepared in accordance with the guidance contained
in North Carolina Erosion and Sediment Control Planning and Desiqn Manual,
2006 Revisions, and have been submitted to the Raleigh Regional Office of the
NC Land Quality Section for review and approval. Typical erosion control
devices such as diversion berms, drainage channels, sediment traps and/or
sediment basins are employed in the design and plan. Financial Responsibility
Forms have been executed and submitted with the plan to the Land Quality
Section.
Reserved Stormwater Drainageway Easement:
A "Reserved Stormwater Drainageway Easement" has been designated on the
plan including the bioretention device and the detention pond and the areas
necessary for maintenance access to these devices.
Analysis:
Analyses of stormwater flows rates and volumes has been performed for the site
(pre-development and post-development conditions) using techniques from
USDA TR-55 and incorporating the Peak Discharge Method. Stormwater runoff
modeling and routing of the detention facilities has been analyzed with the
computer program, Hydroflow Hydrographs by Intelisolve. Calculations were
performed for the 1-year, 2-year, and 25-year, 24-hour storm events. In keeping
with Chapel Hill requirements for release rate management, stormwater
detention has been provided that will control peak flow rates for those storm
events to not be increased above the pre-development rates.

Delineation of Resource Conservation District (RCD):
The perennial stream located to the west of the site crosses under Eubanks
Road and is a tributary to Old Field Creek. The three zones of the RCD, Stream
Side Corridor, Managed Use Corridor and Upland Corridor are all present on the
northwest corner of the site. This RCD is also influenced by the stream from the
opposite side of Eubanks Road. The RCD zones are shown on the Site Plan
drawings.
Release Rate Management:
Release rate analysis has been performed using techniques from USDA TR-55
and incorporating the Peak Discharge Method along with abstractions for the
detention volumes provided. As required by Chapel Hill, calculations have been
provided for the 1-year, 2-year, and 25-year, 24-hour storm event. Using the
bioretention facility for the water quality treatment and the infiltration rate for the
volume management, the peak flow from the given events are being limited on-
site to no more than the pre-development levels in the indicated storm events.
The system proposed will infiltrate the difference in volume for the 1-year and 2-
year events, along with detention and release of the 25-year runoff discharge
through orifice control; and will release the 25-year event runoff at pre-
development rates through the existing roadside drainage system along Eubanks
Road. A comparison of peak discharge flow rates is:
1 year storm 2 year storm 25 year storm
Pre-Development 1.64 cfs 3.69 cfs 17.73 cfs
Post-Development 1.51 cfs 2.45 cfs 15.17 cfs
Volume Management:
Based upon Chapel Hill requirements, the increased volume from the 2-year, 24-
hour storm must be managed onsite. Additional runoff volumes produced in the
2-year, 24-hour storm event is managed in the infiltration zones in the bottom of
the bioretention facility and in the bottom of the detention basin. Infiltration
calculations have been based upon an infiltration rate of 0.6 inches/hour (the low
end of the range for the Georgeville soils) with an effective infiltration rate of 0.3
inches/hour. This rate is expected to infiltrate the additional volume of
stormwater runoff from the 2-year event within a three day period. The infiltration
in the bottom of the bioretention device along with infiltration in the bottom of the
detention basin provides the infiltration capability that is required for infiltration to
meet or exceed the Town requirements.
a,,, 6 n
Water Quality Management:
Chapel Hill requires treatment of stormwater from impervious surfaces
associated with the development to achieve 85% removal of Total Suspended
Solids. This treatment is accomplished by directing the runoff from all the
impervious surfaces, except for a small portion for the entrance driveway leading
in from Eubanks Road and a small portion of the walking trails, to a bioretention
area located in the front of the proposed animal services center. The impervious
areas not captured by the stormwater management system are 8,029 sq. ft.
Conclusion:
The Stormwater Management measures as proposed are designed to meet or
exceed the Town of Chapel Hill's stormwater requirements for release rate
management, volume management and water quality management.
Attachments:
TR 55 Time of Concentration
Curve Number Analysis
BMP Design Calculations
Hydrographs for Pre- and Post-Development Stormwater Runoff
Orange County Soils Survey
Operation and Maintenance Plan for BMPs
PaaP 21
TR55•Tc Worksheet
4
Hydraflow Hydrographs by Intelisolve
Hyd. No. 1
Pre Dev.
Description A B C Totals
Sheet Flow
Manning's n-value = 0.240 0.011 0.011
Flow length (ft) = 100.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.60 0.00 0.00
Land slope (%) = 3.00 0.00 0.00
Travel Time (min) = 11.44 + 0.00 + 0.00 = 11.44
Shallow Concentrated Flow
Flow length (ft) = 150.00 0.00 0.00
Watercourse slope (%) = 3.00 0.00 0.00
Surface description = Unpaved Paved Paved
Average velocity (ft/s) = 2.79 0.00 0.00
Travel Time (min) = 0.89 + 0.00 + 0.00 = 0.89
Channel Flow
X sectional flow area (sqft) = 0.50 0.00 0.00
Wetted perimeter (ft) = 1.50 0.00 0.00
Channel slope (%) = 3.00 0.00 0.00
Manning's n-value = 0.025 0.015 0.015
Velocity (ft/s) = 4.94 0.00 0.00
Flow length (ft) = 300.0 0.0 0.0
Travel Time (min) = 1.01 + 0.00 + 0.00 = 1.01
Total Travel Time, Tc ............. ................................................................. 13.30 min
-;?haP ?.,2-
6
TR55 Tc Worksheet
Hydraflow Hydrographs by intelisolve
Hyd. No. 2
Post dev to Det. Pond
Description A B C Totals
Sheet Flow
Manning's n-value
= 0.011
0.011
0.011
Flow length (ft) = 100.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.60 0.00 0.00
Land slope (%) = 3.00 0.00 0.00
Travel Time (min) = 0.97 + 0.00 + 0.00 = 0.97
Shallow Concentrated Flow
Flow length (ft) = 150.00 0.00 0.00
Watercourse slope (%) = 2.00 0.00 0.00
Surface description = Paved Paved Paved
Average velocity (ft/s) = 2.87 0.00 0.00
Travel Time (min) = 0.87 + 0.00 + 0.00 = 0.87
Channel Flow
X sectional flow area (sqft)
= 0.50
0.00
0.00
Wetted perimeter (ft) = 1.50 0.00 0.00
Channel slope (%) = 2.00 0.00 0.00
Manning's n-value = 0.013 0.015 0.015
Velocity (ft/s) = 7.76 0.00 0.00
Flow length (ft) = 300.0 0.0 0.0
Travel Time (min) = 0.64 + 0.00 + 0.00 = 0.64

...........
Total Travel Time, Tc
.................
......................
........................ 2.50 min
....
Paine M
12
TR55 Tc Worksheet
Hydraflow Hydrographs by Intelisolve
Hyd. No. 6
Post dev not to detention
Description A B C Totals
Sheet Flow
Manning's n-value
= 0.240
0.011
0.011
Flow length (ft) = 100.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.60 0.00 0.00
Land slope (%) = 3.00 0.00 0.00
Travel Time (min) = 11.44 + 0.00 + 0.00 = 11.44
Shallow Concentrated Flow
Flow !er.gth (ft) = 150.00 0.00 0.00
Watercourse slope (%) = 3.00 0.00 0.00
Surface description = Unpaved Paved Paved
Average velocity (ft/s) = 2.79 0.00 0.00
Travel Time (min) = 0.89 + 0.00 + 0.00 = 0.89
Channel Flow
X sectional flow area (sqft) = 0.50 0.00 0.00
Wetted perimeter (ft) = 1.50 0.00 0.00
Channel slope (%) = 3.00 0.00 0.00
Manning's n-value = 0.025 0.015 0.015
Velocity (ft/s) = 4.94 0.00 0.00
Flow length (ft) = 300.0 0.0 0.0
Travel Time (min) = 1.01 + 0.00 + 0.00 = 1.01

...................................
Total Travel Time, Tc
...............
......................... 13.30 min
...
-a"e2?

Project Orange Co Animal Ser
Location Eubanks Rd., Orange Co
Curve Number Analysis
Calculated By WCM Date
Checked By WCM Revised
11/15/2007
Notes
1 Soils are Georgeville - Hydrologic Group B
CIVIL CONSULTANTS, INC.
3708 Lyckan Parkway Suite 201
DURHAM, NC 27707
[phone]
Fax [phone]
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3708 Lyckan Parkway Suite 201
DURHAM, NC 27707
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CIVIL CONSULTANTS, INC.
3708 Lyckan Parkway Suite 201
DURHAM, NC 27707
[phone]
Fax [phone]
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CIVIL CONSULTANTS, INC.
3708 Lyckan Parkway Suite 201
DURHAM, NC 27707
[phone]
Fax [phone]
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(2) EL. 488 e7
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(I) EL_. X86.7 ?
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pond owil-o-f floc for U
0
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SUrfact. Ale-vo? mss . -
0".&,:" Aro.e
Assume all Row is 9o vtirn td 6 y orf,ocJ = 0. 0707 -ft2
?- CD A 29ti WA-eft CD =O.?o
Tor Grale-? O. x 3.r7 232.2) V h
= 0. 6 X 0, 0707 2(32,2)
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3e? n? cor•.l ftis &Af o j 1t at/ c6rr1d "t;oN-S
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04
L-
1" DEPRESSION
1 r-7`/Arr
SECTION G-G
2r-31/4"
12n (0.I(17')
SECTION H-H
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04 i1/2rr
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H
G o G
D
N
1 f?
N 1.3?5? L?H
co
TC
T- 1 r-7j/8rr V-7-5/8"
PLAN OF GRATING
CAST IRON
1/8,
21/8 rr
1/8 rr 1/8 rr
1 rr

3'-344° 1 rr

3/4r, 3
31-2rr

3'-144rr
3r- 611 N N
SECTION E-E
3r-6rr
F?
E
N
F---Wj
PLAN OF FRAME
CAST IRON
E
-4
Dpenmj At-t. c
1•375`' A 0.101 x 16 slots
3.67 ff -
1 rr
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1n
SECTION F-F

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2 c? 2
Hydrographs for Pre- and Post-Development Stormwater Runoff
'.Jn60 A
,Table of Contents
Hydraflow Hydrographs by Intelisolve
13037 detention rev 4-25-08.gpw
Friday, Apr 25 2008, 5:8 PM
Hydrograph Return Period Recap ...................................................................... 1
- Year
Summary Report ................................................................................................................. 2
Hydrograph Reports ........................................................................................................... 3
Hydrograph No. 1, SCS Runoff, Pre Dev ......................................................................... 3
TR-55 Tc Worksheet .................................................................................................... 4
Hydrograph No. 2, SCS Runoff, Post dev to Det. Pond ................................................... 5
TR-55 Tc Worksheet .................................................................................................... 6
Hydrograph No. 3, Diversion1, infiltrate ............................................................................ 7
Hydrograph No. 4, Diversion2, To detention pond ........................................................... 8
Hydrograph No. 5, Reservoir, Detention Pond Outlet ....................................................... 9
Pond Report ............................................................................................................... 10
Hydrograph No. 6, SCS Runoff, Post dev not to detention ............................................. 11
TR-55 Tc Worksheet .................................................................................................. 12
Hydrograph No. 7, Combine, Post Dev. Total ................................................................ 13
2 - Year
Summary Report ............................................................................................................... 14
Hydrograph Reports ......................................................................................................... 15
Hydrograph No. 1, SCS Runoff, Pre Dev ....................................................................... 15
TR-55 Tc Worksheet .................................................................................................. 16
Hydrograph No. 2, SCS Runoff, Post dev to Det. Pond ................................................. 17
TR-55 Tc Worksheet .................................................................................................. 18
Hydrograph No. 3, Diversion1, infiltrate .......................................................................... 19
Hydrograph No. 4, Diversion2, To detention pond ......................................................... 20
Hydrograph No. 5, Reservoir, Detention Pond Outlet ..................................................... 21
Pond Report ............................................................................................................... 22
Hydrograph No. 6, SCS Runoff, Post dev not to detention ............................................. 23
TR-55 Tc Worksheet .................................................................................................. 24
Hydrograph No. 7, Combine, Post Dev. Total ................................................................ 25
10 - Year
Summary Report ............................................................................................................... 26
Hydrograph Reports ......................................................................................................... 27
Hydrograph No. 1, SCS Runoff, Pre Dev ....................................................................... 27
TR-55 Tc Worksheet .................................................................................................. 28
Hydrograph No. 2, SCS Runoff, Post dev to Det. Pond ................................................. 29
TR-55 Tc Worksheet .................................................................................................. 30
Hydrograph No. 3, Diversion1, infiltrate .......................................................................... 31
Hydrograph No. 4, Diversion2, To detention pond ......................................................... 32
Hydrograph No. 5, Reservoir, Detention Pond Outlet ..................................................... 33
Pond Report ...........................................................................................
Hydrograph No. 6, SCS Runoff, Post dev not to detention ............................................. 35
TR-55 Tc Worksheet ........................................................................................
Hydrograph No. 7, Combine, Post Dev. Total ................................................................ 37
25 - Year
n
Contents
13037 detention rev 4-25-08.gpw
Summary Report ............................................................................................................... 38
Hydrograph Reports ......................................................................................................... 39
Hydrograph No. 1, SCS Runoff, Pre Dev ....................................................................... 39
TR-55 Tc Worksheet .................................................................................................. 40
Hydrograph No. 2, SCS Runoff, Post dev to Det. Pond ................................................. 41
TR-55 Tc Worksheet .................................................................................................. 42
Hydrograph No. 3, Diversion1, infiltrate .......................................................................... 43
Hydrograph No. 4, Diversion2, To detention pond ......................................................... 44
Hydrograph No. 5, Reservoir, Detention Pond Outlet ..................................................... 45
Pond Report ...............................................................................................................
46
Hydrograph No. 6, SCS Runoff, Post dev not to detention ............................................. 47
TR-55 Tc Worksheet .................................................................................................. 48
Hydrograph No. 7, Combine, Post Dev. Total ................................................................ 49
100 - Year
Summary Report ............................................................................................................... 50
Hydrograph Reports ......................................................................................................... 51
Hydrograph No. 1, SCS Runoff, Pre Dev ....................................................................... 51
TR-55 Tc Worksheet .................................................................................................. 52
Hydrograph No. 2, SCS Runoff, Post dev to Det. Pond ................................................. 53
TR-55 Tc Worksheet .................................................................................................. 54
Hydrograph No. 3, Diversion1, infiltrate .......................................................................... 55
Hydrograph No. 4, Diversion2, To detention pond ......................................................... 56
Hydrograph No. 5, Reservoir, Detention Pond Outlet ..................................................... 57
Pond Report ...............................................................................................................
58
Hydrograph No. 6, SCS Runoff, Post dev not to detention ............................................. 59
TR-55 Tc Worksheet .................................................................................................. 60
Hydrograph No. 7, Combine, Post Dev. Total ................................................................ 61
on nU. ??
Hydrograph Return Period Recap
Hyd. Hydrograph Inflow Peak Outflow (cfs) Hydrograph

No. type Hyd(s) description
(origin) 1-Yr 2-Yr 3-Yr 5-Yr 10-Yr 25-Yr 50-Yr 100-Yr
1 SCS Runoff ------- 1.64 3.69 ------- ------- 12.02 17.73 ------- 27.40 Pre Dev.
2 SCS Runoff ------- 7.33 10.37 ------- ------- 20.13 26.10 ------- 35.47 Post dev to Det. Pond
3 Diversion1 2 4.25 6.01 ------- ------- 11.68 15.14 ------- 20.58 infiltrate
4 Diversion2 2 3.08 4.36 ------- ------- 8.46 10.96 ------- 14.90 To detention pond
5 Reservoir 4 0.56 0.61 ------- ------- 4.34 8.69 ------- 13.77 Detention Pond Outlet
6 SCS Runoff ------- 0.96 1.85 ------- ------- 5.21 7.44 ------- 11.19 Post dev not to detention
7 Combine 5,6 1.52 2.46 ------- ------- 9.36 15.14 ------- 22.89 Post Dev. Total
I
i
I
I
i
i
i
Proj. file: 13037 detention rev 4-25-08.gpw Friday, Apr 25 2008, 5:07 PM
Hydraflow
Hydrograph Summary Report
Hyd.
No. Hydrograph
type
(origin) Peak
flow
(cfs) Time
interval
(min) Time to
peak
(min) Volume

(cuft) Inflow
hyd(s) Maximum
elevation
(ft) Maximum
storage
(cult) Hydrograph
description
1 SCS Runoff 1.64 1 724 6,967 ---- ------ ------ Pre Dev.
2 SCS Runoff 7.33 1 716 12,746 ---- ------ ------ Post dev to Det. Pond
3 Diversionl 4.25 1 716 7,393 2 ------ ------ infiltrate
4 Diversion2 3.08 1 716 5,353 2 ------ ------ To detention pond
5 Reservoir 0.56 1 723 5,353 4 486.45 1,389 Detention Pond Outlet
6 SCS Runoff 0.96 1 723 3,340 ---- ------ ------ Post dev not to detention
7 Combine 1.52 1 723 8,694 5,6 ------ ------ Post Dev. Total
I
I
13037 detention rev 4-25-08.gpw Return Period: 1 Year Friday, Apr 25 2008, 5:07 PM
Hydraflow Hydrographs by Intelisolve
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve
Hyd. No. 1
Pre Dev.
Hydrograph type = SCS Runoff
Storm frequency = 1 yrs
Drainage area = 5.85 ac
Basin Slope = 0.0%
Tc method = TR55
Total precip. = 3.00 in
Storm duration = 24 hrs
Friday, Apr 25 2008, 5:7 PM
Peak discharge = 1.64 cfs
Time interval = 1 min
Curve number = 60
Hydraulic length = 0 ft
Time of conc. (Tc) = 13.3 min
Distribution = Type II
Shape factor = 484
Hydrograph Volume = 6,967 cult
Q (cfs) Pre Dev.
Hyd. No. 1 -- 1 Yr
2.00
1.00
0.00
0
2 5 7 9 12 14 16 19 21 23
Hyd No. 1
Q (cfs)
2.00
1.00
0.00
26
Time (hrs)
3
P - kr
TR55 Tc Worksheet
Hydraflow Hydrographs by Intelisolve
Hyd. No. 1
Pre Dev.
Description A B C Totals
Sheet Flow
Manning's n-value = 0.240 0.011 0.011
Flow length (ft) = 100.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.60 0.00 0.00
Land slope (%) = 3.00 0.00 0.00
Travel Time (min) = 11.44 + 0.00 + 0.00 = 11.44
Shallow Concentrated Flow
Flow length (ft) = 150.00 0.00 0.00
Watercourse slope (%) = 3.00 0.00 0.00
Surface description = Unpaved Paved Paved
Average velocity (ft/s) = 2.79 0.00 0.00
Travel Time (min) = 0.89 + 0.00 + 0.00 = 0.89
Channel Flow
X sectional flow area (sqft) = 0.50 0.00 0.00
Wetted perimeter (ft) = 1.50 0.00 0.00
Channel slope (%) = 3.00 0.00 0.00
Manning's n-value = 0.025 0.015 0.015
Velocity (ft/s) = 4.94 0.00 0.00
Flow length (ft) = 300.0 0.0 0.0
Travel Time (min) = 1.01 + 0.00 + 0.00 = 1.01
Total Travel Time, Tc .............................. ...................... .......................... 13.30 min
4
A.., -? 1
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:7 PM
Hyd. No. 2
Post dev to Det. Pond
Hydrograph type = SCS Runoff Peak discharge = 7.33 cfs
Storm frequency = 1 yrs Time interval = 1 min
Drainage area = 3.69 ac Curve number = 76
Basin Slope = 0.0% Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 2.5 min
Total precip. = 3.00 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Hydrograph Volume = 12,746 cuft
Post dev to Det. Pond
Q (cfs) Hyd. No. 2 -- 1 Yr
8.00
6.00
4.00
2.00
0.00
0
2 5
Hyd No. 2
7 9 12 14 16 19 21
Q (cfs)
8.00
6.00
4.00
2.00
0.00
23 26
Time (hrs)
5
V)'.0 ,
TR55 Tc Worksheet
Hydraflow Hydrographs by Intelisolve
Hyd. No. 2
Post dev to Det. Pond
Description A B C Totals
Sheet Flow
Manning's n-value = 0.011 0.011 0.011
Flow length (ft) = 100.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.60 0.00 0.00
Land slope (%) = 3.00 0.00 0.00
Travel Time (min) = 0.97 + 0.00 + 0.00 = 0.97
Shallow Concentrated Flow
Flow length (ft) = 150.00 0.00 0.00
Watercourse slope (%) = 2.00 0.00 0.00
Surface description = Paved Paved Paved
Average velocity (ft/s) = 2.87 0.00 0.00
Travel Time (min) = 0.87 + 0.00 + 0.00 = 0.87
Channel Flow
X sectional flow area (sqft) = 0.50 0.00 0.00
Wetted perimeter (ft) = 1.50 0.00 0.00
Channel slope (%) = 2.00 0.00 0.00
Manning's n-value = 0.013 0.015 0.015
Velocity (ft/s) = 7.76 0.00 0.00
Flow length (ft) = 300.0 0.0 0.0
Travel Time (min) = 0.64 + 0.00 + 0.00 = 0.64
Total Travel Time, Tc .............................. ................................................ 2.50 min
6
PAL 313
Hydrograph Plot 7
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:7 PM
Hyd. No. 3
infiltrate
Hydrograph type = Diversion'! Peak discharge = 4.25 cfs
Storm frequency = 1 yrs Time interval = 1 min
Inflow hydrograph = 2 2nd diverted hyd. = 4
Diversion method = Flow Ratio Flow ratio = 0.58
Hydrograph Volume = 7,393 cult
infiltrate
Q (cfs) Hyd. No. 3 -- 1 Yr
8.00
6.00
4.00
2.00
0.00
0
2 5 7 9 12 14 16
Hyd No. 3 Hyd No. 2 Hyd No. 4
19 21
Q (cfs)
8.00
6.00
4.00
2.00
0.00
23 26
Time (hrs)
A'.'4h
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:7 PM
Hyd. No. 4
To detention pond
Hydrograph type = Diversion2 Peak discharge = 3.08 cfs
Storm frequency = 1 yrs Time interval = 1 min
Inflow hydrograph = 2 2nd diverted hyd . = 3
Diversion method = Flow Ratio Flow ratio = 0.58
Hydrograph Volume = 5,353 cuft
To detention pond
Q (cfs) Q (cfs
Hyd. No. 4 -- 1 Yr )
8.00 8.00
6.00
4.00
2.00
0.00
0
2 5 7 9 12 14 16 19 21
Hyd No. 4 Hyd No. 2 Hyd No. 3
6.00
4.00
2.00
0.00
23 26
Time (hrs)
PA a .4I
8
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:7 PM
Hyd. No. 5
Detention Pond Outlet
Hydrograph type = Reservoir Peak discharge = 0.56 cfs
Storm frequency = 1 yrs Time interval = 1 min
Inflow hyd. No. = 4 Max. Elevation = 486.45 ft
Reservoir name = Detention Pond Max. Storage = 1,389 cuft
Storage Indication method used.
Q (cfs)
4.00
3.00
2.00
1.00
0.00
0
2 5
Hyd No. 5
Detention Pond Outlet
Hyd. No. 5 -- 1 Yr
7 9
- Hyd No. 4
Hydrograph Volume = 5,353 cuft
Q (cfs)
4.00
3.00
2.00
1.00
0.00
12 14 16 19 21 23 26
Time (hrs)
9
Pmt _ --
Hydr'ograph Plot
Hydraflow Hydrographs by Intelisolve
Hyd. No. 6
Post dev not to detention
Hydrograph type = SCS Runoff
Storm frequency = 1 yrs
Drainage area = 2.16 ac
Basin Slope = 0.0%
Tc method = TR55
Total precip. = 3.00 in
Storm duration = 24 hrs
Friday, Apr 25 2008, 5:7 PM
Peak discharge = 0.96 cfs
Time interval = 1 min
Curve number = 63
Hydraulic length = 0 ft
Time of conc. (Tc) = 13.3 min
Distribution = Type II
Shape factor = 484
Hydrograph Volume = 3,340 cuft
Q (cfs)
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
0
Post dev not to detention
Hyd. No. 6 -- 1 Yr
Q (cfs)
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
26
Time (hrs)
04,.E * -
11
2 5 7 9 12 14 16 19 21 23
Hyd No. 6
'TR55 Tc Worksheet
Hydraflow Hydrographs by Intelisolve
Hyd. No. 6
Post dev not to detention
Description A B C Totals
Sheet Flow
Manning's n-value = 0.240 0.011 0.011
Flow length (ft) = 100.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.60 0.00 0.00
Land slope (%) = 3.00 0.00 0.00
Travel Time (min) = 11.44 + 0.00 + 0.00 = 11.44
Shallow Concentrated Flow
Flow length (ft) = 150.00 0.00 0.00
Watercourse slope (%) = 3.00 0.00 0.00
Surface description = Unpaved Paved Paved
Average velocity (ft/s) = 2.79 0.00 0.00
Travel Time (min) = 0.89 + 0.00 + 0.00 = 0.89
Channel Flow
X sectional flow area (sqft) = 0.50 0.00 0.00
Wetted perimeter (ft) = 1.50 0.00 0.00
Channel slope (%) = 3.00 0.00 0.00
Manning's n-value = 0.025 0.015 0.015
Velocity (ft/s) = 4.94 0.00 0.00
Flow length (ft) = 300.0 0.0 0.0
Travel Time (min) = 1.01 + 0.00 + 0.00 = 1.01
Total Travel Time, Tc ............. ................. ........................... ..................... 13.30 min
12
Fin no A<
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:7 PM
Hyd. No. 7
Post Dev. Total
Hydrograph type = Combine Peak discharge = 1.52 cfs
Storm frequency = 1 yrs Time interval = 1 min
Inflow hyds. = 5, 6
Hydrograph Volume = 8,694 cuft
Post Dev. Total
Q (cfs)
Hyd. No. 7 -- 1 Yr
2.00
1.00
0.00
0
2 5 7 9 12 14 16
Hyd No. 7 Hyd No. 5 Hyd No. 6
19 21 23
Q (cfs)
2.00
1.00
0.00
26
Time (hrs)
13
ow- *
14
Hydrograph Summary Report
Hyd.
No. Hydrograph
type
(origin) Peak
flow
(cfs) Time
interval
(min) Time to
peak
(min) Volume

(cuft) Inflow
hyd(s) Maximum
elevation
(ft) Maximum
storage
(cuft) Hydrograph
description
1 SCS Runoff 3.69 1 723 12,021 ---- ------ ------ Pre Dev.
2 SCS Runoff 10.37 1 716 18,062 ---- ------ ------ Post dev to Det. Pond
3 Diversionl 6.01 1 716 10,476 2 ------ ------ infiltrate
4 Diversion2 4.36 1 716 7,586 2 ------ ------ To detention pond
5 Reservoir 0.61 1 724 7,586 4 486.99 2,295 Detention Pond Outlet
6 SCS Runoff 1.85 1 722 5,471 ---- ------ ------ Post dev not to detention
7 Combine 2.46 1 722 13,057 5,6 ------ ------ Post Dev. Total
i
i
13037 detention rev 4-25-08.gpw Return Period: 2 Year Friday, Apr 25 2008, 5:07 PM
Hydraflow HydroVph Eby Intelisolve
J A
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:8 PM
Hyd. No. 1
Pre Dev.
Hydrograph type = SCS Runoff Peak discharge = 3.69 cfs
Storm frequency = 2 yrs Time interval = 1 min
Drainage area = 5.85 ac Curve number = 60
Basin Slope = 0.0% Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 13.3 min
Total precip. = 3.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Hydrograph Volume = 12,021 cuft
Pre Dev.
Q (cfs) Hyd. No. 1 -- 2 Yr
4.00
3.00
2.00
1.00
0.00
0
2 5
Hyd No. 1
7 9 12 14
Q (cfs)
4.00
3.00
2.00
1.00
0.00
16 19 21 23 26
Time (hrs)
15
Ofine A
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:8 PM
Hyd. No. 2
Post dev to Det. Pond
Hydrograph type = SCS Runoff Peak discharge = 10.37 cfs
Storm frequency = 2 yrs Time interval = 1 min
Drainage area = 3.69 ac Curve number = 76
Basin Slope = 0.0% Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 2.5 min
Total precip. = 3.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Hydrograph Volume = 18,062 cult
Post dev to Det. Pond
Q (cfs) Hyd. No. 2 -- 2 Yr
12.00
10.00
8.00
6.00
4.00
2.00
0.00
0 2 5 7 9
Hyd No. 2
Q (cfs)
12.00
10.00
8.00
6.00
4.00
2.00
0.00
12 14 16 19 21 23 26
Time (hrs)
nA'V 50
17
TR55 Tc Worksheet
Hydraflow Hydrographs by Intelisolve
Hyd. No. 2
Post dev to Det. Pond
Description A B C Totals
Sheet Flow
Manning's n-value = 0.011 0.011 0.011
Flow length (ft) = 100.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.60 0.00 0.00
Land slope (%) = 3.00 0.00 0.00
Travel Time (min) = 0.97 + 0.00 + 0.00 = 0.97
Shallow Concentrated Flow
Flow length (ft) = 150.00 0.00 0.00
Watercourse slope (%) = 2.00 0.00 0.00
Surface description = Paved Paved Paved
Average velocity (ft/s) = 2.87 0.00 0.00
Travel Time (min) = 0.87 + 0.00 + 0.00 = 0.87
Channel Flow
X sectional flow area (sqft) = 0.50 0.00 0.00
Wetted perimeter (ft) = 1.50 0.00 0.00
Channel slope (%) = 2.00 0.00 0.00
Manning's n-value = 0.013 0.015 0.015
Velocity (ft/s) = 7.76 0.00 0.00
Flow length (ft) = 300.0 0.0 0.0
Travel Time (min) = 0.64 + 0.00 + 0.00 = 0.64
Total Travel Time, Tc .............................................................................. 2.50 min
18
D(k Si
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:8 PM
Hyd. No. 3
infiltrate
Hydrograph type = Diversion1 Peak discharge = 6.01 cfs
Storm frequency = 2 yrs Time interval = 1 min
Inflow hydrograph = 2 2nd diverted hyd. = 4
Diversion method = Flow Ratio Flow ratio = 0.58
Hydrograph Volume = 10,476 cuft
infiltrate
Q (cfs) Hyd. No. 3 -- 2 Yr
12.00
10.00
8.00
6.00
4.00
2.00
0.00
0 2 5 7 9
Hyd No. 3 Hyd No. 2
Q (cfs)
12.00
10.00
8.00
6.00
4.00
2.00
0.00
12 14 16 19 21 23 26
Hyd No. 4 Time (hrs)

19
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:8 PM
Hyd. No. 4
To detention pond
Hydrograph type = Diversion2 Peak discharge = 4.36 cfs
Storm frequency = 2 yrs Time interval = 1 min
Inflow hydrograph = 2 2nd diverted hyd. = 3
Diversion method = Flow Ratio Flow ratio = 0.58
Hydrograph Volume = 7,586 cuft
Q (cfs) To detention pond
Hyd. No. 4 -- 2 Yr
12.00
10.00
8.00
6.00
4.00
2.00
0.00
0 2 5 7 9
Hyd No. 4 Hyd No. 2
10.00
8.00
6.00
4.00
2.00
0.00
12 14 16 19 21 23 26
Hyd No. 3 Time (hrs)
Q (cfs)
12.00
- Pt, ?-;
20
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:8 PM
Hyd. No. 5
Detention Pond Outlet
Hydrograph type = Reservoir Peak discharge = 0.61 cfs
Storm frequency = 2 yrs Time interval = 1 min
Inflow hyd. No. = 4 Max. Elevation = 486.99 ft
Reservoir name = Detention Pond Max. Storage = 2,295 cuft
Storage Indication method used.
Q (cfs)
5.00
4.00
3.00
2.00
1.00
0.00
0
Detention Pond Outlet
Hyd. No. 5 -- 2 Yr
2 5 7 9
Hyd No. 5 Hyd No. 4
Hydrograph Volume = 7,586 cuft
4.00
3.00
2.00
1.00
0.00
12 14 16 19 21 23 26
Time (hrs)
Q (cfs)
5.00
21
PA. 64
.Pond Report
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:8 PM
Pond No. 1 - Detention Pond
Pond Data
Pond storage is based on known contour areas. Average end area method used.
Stage / Storage Table
Stage (ft) Elevation (ft) Contour area (sgft) Incr. Storage (cuft) Total storage (cuft)
0.00 483.50 00 0 0
1.50 485.00 25 19 19
2.50 486.00 1,202 614 632
4.50 488.00 2,155 3,357 3,989
6.50 490.00 3,334 5,489 9,478
Culvert/ Orifice Structures
[A] [B] [C] [D]
Rise (in) = 18.00 3.60 0.00 0.00
Span (in) = 18.00 3.60 0.00 0.00
No. Barrels = 1 1 0 0
Invert El. (ft) = 483.00 483.60 0.00 0.00
Length (ft) = 70.00 0.00 0.00 0.00
Slope (%) = 2.00 0.00 0.00 0.00
N-Value = .013 .013 .013 .013
Orif. Coeff. = 0.60 0.60 0.60 0.60
Multi-Stage = n/a Yes No No
Stage (ft)
7.00
6.00
5.00
4.00
3.00
2.00
1.00
0.00
0.00
Weir Structures
[A] [B] [C] [D]
Crest Len (ft) = 9.00 0.00 0.00 0.00
Crest El. (ft) = 488.00 0.00 0.00 0.00
Weir Coeff. = 3.33 3.33 0.00 0.00
Weir Type = Riser --- --- ---
Multi-Stage = Yes No No No
Exfiltration = 0.000 in/hr (Contour) Tailwater Elev. = 0.00 ft
Note. Culvert/Orifice outflows have been analyzed under inlet and outlet control.
Stage / Discharge
22
Stage (ft)
7.00
6.00
5.00
4.00
3.00
2.00
1.00
0.00
18.00 20.00 22.00
Discharge (cfs)
PA.1 ?l -
2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00
- - Total O
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve
Hyd. No. 6
Post dev not to detention
Hydrograph type = SCS Runoff
Storm frequency = 2 yrs
Drainage area = 2.16 ac
Basin Slope = 0.0%
Tc method = TR55
Total precip. = 3.60 in
Storm duration = 24 hrs
Friday, Apr 25 2008, 5:8 PM
Peak discharge = 1.85 cfs
Time interval = 1 min
Curve number = 63
Hydraulic length = 0 ft
Time of conc. (Tc) = 13.3 min
Distribution = Type II
Shape factor = 484
Post dev not to detention
Q (cfs) Hyd. No. 6 -- 2 Yr
2.00
1.00
Q (cfs)
2.00
1.00
0.00 0.00
0 2 5 7 9 12 14 16 19 21 23 26
Hyd No. 6 Time (hrs)
PA,V- sb
Hydrograph Volume = 5,471 cuft
23
TR55 Tc Worksheet
Hydraflow Hydrographs by Intelisolve
Hyd. No. 6
Post dev not to detention
Description A B C Totals
Sheet Flow
Manning's n-value = 0.240 0.011 0.011
Flow length (ft) = 100.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.60 0.00 0.00
Land slope (%) = 3.00 0.00 0.00
Travel Time (min) = 11.44 + 0.00 + 0.00 = 11.44
Shallow Concentrated Flow
Flow length (ft) = 150.00 0.00 0.00
Watercourse slope (%) = 3.00 0.00 0.00
Surface description = Unpaved Paved Paved
Average velocity (ft/s) = 2.79 0.00 0.00
Travel Time (min) = 0.89 + 0.00 + 0.00 = 0.89
Channel Flow
X sectional flow area (sqft) = 0.50 0.00 0.00
Wetted perimeter (ft) = 1.50 0.00 0.00
Channel slope (%) = 3.00 0.00 0.00
Manning's n-value = 0.025 0.015 0.015
Velocity (ft/s) = 4.94 0.00 0.00
Flow length (ft) = 300.0 0.0 0.0
Travel Time (min) = 1.01 + 0.00 + 0.00 = 1.01
Total Travel Time, Tc .............................................................................. 13.30 min
i
24
L. 51
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:8 PM
Hyd. No. 7
Post Dev. Total
Hydrograph type = Combine Peak discharge = 2.46 cfs
Storm frequency = 2 yrs Time interval = 1 min
Inflow hyds. = 5, 6
Hydrograph Volume = 13,057 cuft
Q (cfs)
3.00
2.00
1.00
0.00
0
Post Dev. Total
Hyd. No. 7 -- 2 Yr
2 5 7 9 12 14 16 19 21
Hyd No. 7 Hyd No. 5 Hyd No. 6
Q (cfs)
3.00
2.00
1.00
0.00
23 26
Time (hrs)
25
W„., AG
Hydrograph Summary Report
26
Hyd.
No. Hydrograph
type
(origin) Peak
flow
(cfs) Time
interval
(min) Time to
peak
(min) Volume

(cult) Inflow
hyd(s) Maximum
elevation
(ft) Maximum
storage
(cult) Hydrograph
description
1 SCS Runoff 12.02 1 722 31,952 ---- ------ ------ Pre Dev.
2 SCS Runoff 20.13 1 716 35,812 ---- ------ ------ Post dev to Det. Pond
3 Diversion1 11.68 1 716 20,771 2 ------ ------ infiltrate
4 Diversion2 8.46 1 716 15,041 2 ------ ------ To detention pond
5 Reservoir 4.34 1 720 15,041 4 488.24 4,646 Detention Pond Outlet
6 SCS Runoff 5.21 1 722 13,544 ---- ------ ------ Post dev not to detention
7 Combine 9.36 1 720 28,585 5,6
I ------ ------ Post Dev. Total

I
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13037 detention rev 4-25-08.gpw Return Period: 10 Year Friday, Apr 25 2008, 5:08 PM
Hydraflow Hydrograpjht by Intehpolve
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:8 PM
Hyd. No. 1
Pre Dev.
Hydrograph type = SCS Runoff Peak discharge = 12.02 cfs
Storm frequency = 10 yrs Time interval = 1 min
Drainage area = 5.85 ac Curve number = 60
Basin Slope = 0.0% Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 13.3 min
Total precip. = 5.38 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Hydrograph Volume = 31,952 cuft
Pre Dev.
Q (cfs)
Hyd. No. 1 -- 10 Yr
14.00
12.00
10.00
8.00
6.00
4.00
2.00
0.00
0 2 5
Hyd No. 1
Q (cfs)
14.00
12.00
10.00
8.00
6.00
4.00
2.00
0.00
7 9 12 14 16 19 21 23 26
Time (hrs)
PA. 6 6
27
TR55 Tc Worksheet
Hydraflow Hydrographs by Intelisolve
Hyd. No. 1
Pre Dev.
Description A B C Totals
Sheet Flow
Manning's n-value = 0.240 0.011 0.011
Flow length (ft) = 100.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.60 0.00 0.00
Land slope (%) = 3.00 0.00 0.00
Travel Time (min) = 11.44 + 0.00 + 0.00 = 11.44
Shallow Concentrated Flow
Flow length (ft) = 150.00 0.00 0.00
Watercourse slope (%) = 3.00 0.00 0.00
Surface description = Unpaved Paved Paved
Average velocity (ft/s) = 2.79 0.00 0.00
Travel Time (min) = 0.89 + 0.00 + 0.00 = 0.89
Channel Flow
X sectional flow area (sqft) = 0.50 0.00 0.00
Wetted perimeter (ft) = 1.50 0.00 0.00
Channel slope (%) = 3.00 0.00 0.00
Manning's n-value = 0.025 0.015 0.015
Velocity (ft/s) = 4.94 0.00 0.00
Flow length (ft) = 300.0 0.0 0.0
Travel Time (min) = 1.01 + 0.00 + 0.00 = 1.01
28
Total Travel Time, Tc .............................................................................. 13.30 min
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:8 PM
Hyd. No. 2
Post dev to Det. P ond
Hydrograph type = SCS Runoff Peak discharge = 20.13 cfs
Storm frequency = 10 yrs Time interval = 1 min
Drainage area = 3.69 ac Curve number = 76
Basin Slope = 0.0% Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 2.5 min
Total precip. = 5.38 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Hydrograph Volume = 35,812 cuft
Q (cfs)
21.00
18.00
15.00
12.00
9.00
6.00
3.00
Post dev to Det. Pond
Hyd. No. 2 -- 10 Yr
Q (cfs)
21.00
18.00
15.00
12.00
9.00
6.00
3.00
0.00 0.00
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 22.0
Hyd No. 2 Time (hrs)
chat (I.l
29
TR55 Tc Worksheet
Hydraflow Hydrographs by Intelisolve
Hyd. No. 2
Post dev to Det. Pond
Description A B C Totals
Sheet Flow
Manning's n-value = 0.011 0.011 0.011
Flow length (ft) = 100.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.60 0.00 0.00
Land slope (%) = 3.00 0.00 0.00
Travel Time (min) = 0.97 + 0.00 + 0.00 = 0.97
Shallow Concentrated Flow
Flow length (ft) = 150.00 0.00 0.00
Watercourse slope (%) = 2.00 0.00 0.00
Surface description = Paved Paved Paved
Average velocity (ft/s) = 2.87 0.00 0.00
Travel Time (min) = 0.87 + 0.00 + 0.00 = 0.87
Channel Flow
X sectional flow area (sqft) = 0.50 0.00 0.00
Wetted perimeter (ft) = 1.50 0.00 0.00
Channel slope (%) = 2.00 0.00 0.00
Manning's n-value = 0.013 0.015 0.015
Velocity (ft/s) = 7.76 0.00 0.00
Flow length (ft) = 300.0 0.0 0.0
Travel Time (min) = 0.64 + 0.00 + 0.00 = 0.64
Total Travel Time, Tc ............. ................................................................. 2.50 min
30
P,,L6i
Hydrbgraph Plot
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:8 PM
Hyd. No. 3
infiltrate
Hydrograph type = Diversion1 Peak discharge = 11.68 cfs
Storm frequency = 10 yrs Time interval = 1 min
Inflow hydrograph = 2 2nd diverted hyd. = 4
Diversion method = Flow Ratio Flow ratio = 0.58
Hydrograph Volume = 20,771 cuft
infiltrate
Q (cfs) Hyd. No. 3 -- 10 Yr
21.00
18.00
15.00
12.00
9.00
6.00
3.00
Q (cfs)
21.00
18.00
15.00
12.00
9.00
6.00
3.00
0.00 0.00
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 22.0
Hyd No. 3 Hyd No. 2 Hyd No. 4 Time (hrs)
PiAf- lod
31
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:8 PM
Hyd. No. 4
To detention pond
Hydrograph type = Diversion2 Peak discharge = 8.46 cfs
Storm frequency = 10 yrs Time interval = 1 min
Inflow hydrograph = 2 2nd diverted hyd. = 3
Diversion method = Flow Ratio Flow ratio = 0.58
Hydrograph Volume = 15,041 cuft
Q (cfs)
21.00
18.00
15.00
12.00
9.00
6.00
3.00
Q (cfs)
21.00
18.00
15.00
12.00
9.00
6.00
3.00
0.00 0.00
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 22.0
Hyd No. 4 Hyd No. 2 Hyd No. 3 Time (hrs)
PW v
32
To detention pond
Hyd. No. 4 -- 10 Yr
Hydr'ograph Plot
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:8 PM
Hyd. No. 5
Detention Pond Outlet
Hydrograph type = Reservoir Peak discharge = 4.34 cfs
Storm frequency = 10 yrs Time interval = 1 min
Inflow hyd. No. = 4 Max. Elevation = 488.24 ft
Reservoir name = Detention Pond Max. Storage = 4,646 cuft
Storage Indication method used.
Hydrograph Volume = 15,041 cuft
Q (cfs)
10.00
8.00
6.00
4.00
2.00
0.00
0
2 5
Hyd No. 5
7
Detention Pond Outlet
Hyd. No. 5 -- 10 Yr
8.00
6.00
4.00
2.00
0.00
9 12 14 16 19 21 23 26
Hyd No. 4 Time (hrs)
Q (cfs)
10.00
33

Pond Report
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:8 PM
Pond No. 1 - Detention Pond
Pond Data
Pond storage is based on known contour areas. Average end area method used.
Stage / Storage Table
Stage (ft) Elevation (ft) Contour area (sgft) Incr. Storage (cuft) Total storage (cult)
0.00 483.50 00 0 0
1.50 485.00 25 19 19
2.50 486.00 1,202 614 632
4.50 488.00 2,155 3,357 3,989
6.50 490.00 3,334 5,489 9,478
Culvert / Orifice Structures Weir Structures
[A] [B] [C] [D] [A] [B] [C] [D]
Rise (in) = 18.00 3.60 0.00 0.00 Crest Len (ft) = 9.00 0.00 0.00 0.00
Span (in) = 18.00 3.60 0.00 0.00 Crest El. (ft) = 488.00 0.00 0.00 0.00
No. Barrels = 1 1 0 0 Weir Coeff. = 3.33 3.33 0.00 0.00
Invert El. (ft) = 483.00 483.60 0.00 0.00 Weir Type = Riser --- --- ---
Length (ft) = 70.00 0.00 0.00 0.00 Multi-Stage = Yes No No No
Slope (%) = 2.00 0.00 0.00 0.00
N-Value = .013 .013 .013 .013
Orif. Coeff. = 0.60 0.60 0.60 0.60
Multi-Stage = n/a Yes No No Exfiltration = 0.000 in/hr (Contour) Tai lwater Elev. = 0.00 ft
Note Culvert/Orifice outflows have been analyzed under inlet and outlet control.
Stage (ft)
7.00
6.00
5.00
4.00
3.00
2.00
1.00
0.00
0.00
Stage / Discharge
Stage (ft)
p34
7.00
6.00
5.00
4.00
3.00
2.00
1.00
0.00
18.00 20.00 22.00
Discharge (cfs)

2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00
- Total Q
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:8 PM
Hyd. No. 6
Post dev not to detention
Hydrograph type = SCS Runoff Peak discharge = 5.21 cfs
Storm frequency = 10 yrs Time interval = 1 min
Drainage area = 2.16 ac Curve number = 63
Basin Slope = 0.0% Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 13.3 min
Total precip. = 5.38 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Hydrograph Volume = 13,544 cuft
Post dev not to detention
Q (cfs) Hyd. No. 6 -- 10 Yr
6.00
5.00
4.00
3.00
2.00
1.00
0.00
0 2 5 7 9
Hyd No. 6
Q (cfs)
6.00
5.00
4.00
3.00
2.00
1.00
0.00
12 14 16 19 21 23 26
Time (hrs)
A. • /a A
35
TR55 Tc Worksheet
Hydraflow Hydrographs by Intelisolve
Hyd. No. 6
Post dev not to detention
Description A B C Totals
Sheet Flow
Manning's n-value = 0.240 0.011 0.011
Flow length (ft) = 100.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.60 0.00 0.00
Land slope (%) = 3.00 0.00 0.00
Travel Time (min) = 11.44 + 0.00 + 0.00 = 11.44
Shallow Concentrated Flow
Flow length (ft) = 150.00 0.00 0.00
Watercourse slope (%) = 3.00 0.00 0.00
Surface description = Unpaved Paved Paved
Average velocity (ft/s) = 2.79 0.00 0.00
Travel Time (min) = 0.89 + 0.00 + 0.00 = 0.89
Channel Flow
X sectional flow area (sqft) = 0.50 0.00 0.00
Wetted perimeter (ft) = 1.50 0.00 0.00
Channel slope (%) = 3.00 0.00 0.00
Manning's n-value = 0.025 0.015 0.015
Velocity (ft/s) = 4.94 0.00 0.00
Flow length (ft) = 300.0 0.0 0.0
Travel Time (min) = 1.01 + 0.00 + 0.00 = 1.01
Total Travel Time, Tc ..................................... ............... ...................... .... 13.30 min
36
Om, (P q
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:8 PM
Hyd. No. 7
Post Dev. Total
Hydrograph type = Combine Peak discharge = 9.36 cfs
Storm frequency = 10 yrs Time interval = 1 min
Inflow hyds. = 5, 6
Hydrograph Volume = 28,585 cuft
Post Dev. Total
Q (cfs) Hyd. No. 7 -- 10 Yr
10.00
8.00
6.00
4.00
2.00
0.00
0
2 5
Hyd No. 7
7
9
Hyd No. 5
Q (cfs)
10.00
8.00
6.00
4.00
2.00
I t- 0.00
12 14 16 19 21 23 26
Hyd No. 6 Time (hrs)
37
I'nat ill
38
Hydrograph Summary Report
Hyd.
No. Hydrograph
type
(origin) Peak
flow
(cfs) Time
interval
(min) Time to
peak
(min) Volume

(cuft) Inflow
hyd(s) Maximum
elevation
(ft) Maximum
storage
(cuft) Hydrograph
description
1 SCS Runoff 17.73 1 722 45,876 ---- ------ ------ Pre Dev.
2 SCS Runoff 26.10 1 715 46,921 ---- ------ ------ Post dev to Det. Pond
3 Diversionl 15.14 1 715 27,214 2 ------ ------ infiltrate
4 Diversion2 10.96 1 715 19,707 2 ------ ------ To detention pond
5 Reservoir 8.69 1 718 19,706 4 488.41 5,127 Detention Pond Outlet
6 SCS Runoff 7.44 1 721 19,044 ---- ------ ------ Post dev not to detention
7 Combine 15.14 1 718 38,751 5,6 ------ ------ Post Dev. Total
i
i
i
i
I
13037 detention rev 4-25-08.gpw Return Period: 25 Year Friday, Apr 25 2008, 5:08 PM
Hydraflow Hydrogiphs by.lotelisolve
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:8 PM
Hyd. No. 1
Pre Dev.
Hydrograph type = SCS Runoff Peak discharge = 17.73 cfs
Storm frequency = 25 yrs Time interval = 1 min
Drainage area = 5.85 ac Curve number = 60
Basin Slope = 0.0% Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 13.3 min
Total precip. = 6.41 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Hydrograph Volume = 45,876 cuft
Q (cfs)
18.00
15.00
12.00
9.00
6.00
3.00
0.00
0 2 5 7
Hyd No. 1
Pre Dev.
Hyd. No. 1 -- 25 Yr
Q (cfs)
18.00
15.00
12.00
9.00
6.00
3.00
0.00
9 12 14 16 19 21 23 26
Time (hrs)
39
pa-? I ?-
TR55 Tc Worksheet
Hydraflow Hydrographs by Intelisolve
Hyd. No. 1
Pre Dev.
Description A B C Totals
Sheet Flow
Manning's n-value = 0.240 0.011 0.011
Flow length (ft) = 100.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.60 0.00 0.00
Land slope (%) = 3.00 0.00 0.00
Travel Time (min) = 11.44 + 0.00 + 0.00 = 11.44
Shallow Concentrated Flow
Flow length (ft) = 150.00 0.00 0.00
Watercourse slope (%) = 3.00 0.00 0.00
Surface description = Unpaved Paved Paved
Average velocity (ft/s) = 2.79 0.00 0.00
Travel Time (min) = 0.89 + 0.00 + 0.00 = 0.89
Channel Flow
X sectional flow area (sqft) = 0.50 0.00 0.00
Wetted perimeter (ft) = 1.50 0.00 0.00
Channel slope (%) = 3.00 0.00 0.00
Manning's n-value = 0.025 0.015 0.015
Velocity (ft/s) = 4.94 0.00 0.00
Flow length (ft) = 300.0 0.0 0.0
Travel Time (min) = 1.01 + 0.00 + 0.00 = 1.01
Total Travel Time, Tc ............. ................. ................................................ 13.30 min
40
PaaL_ 13
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:8 PM
Hyd. No. 2
Post dev to Det. Pond
Hydrograph type = SCS Runoff Peak discharge = 26.10 cfs
Storm frequency = 25 yrs Time interval = 1 min
Drainage area = 3.69 ac Curve number = 76
Basin Slope = 0.0% Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 2.5 min
Total precip. = 6.41 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Hydrograph Volume = 46,921 cult
Post dev to Det. Pond
Q (cfs) Hyd. No. 2 -- 25 Yr
28.00
24.00
20.00
16.00
12.00
8.00
4.00
Q (cfs)
28.00
24.00
20.00
16.00
12.00
8.00
4.00
0.00 0.00
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0
Hyd No. 2 Time (hrs)
41
Lit 14
TR55 Tc Worksheet
Hydraflow Hydrographs by Intelisolve
Hyd. No. 2
Post dev to Det. Pond
Description A B C Totals
Sheet Flow
Manning's n-value = 0.011 0.011 0.011
Flow length (ft) = 100.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.60 0.00 0.00
Land slope (%) = 3.00 0.00 0.00
Travel Time (min) = 0.97 + 0.00 + 0.00 = 0.97
Shallow Concentrated Flow
Flow length (ft) = 150.00 0.00 0.00
Watercourse slope (%) = 2.00 0.00 0.00
Surface description = Paved Paved Paved
Average velocity (ft/s) = 2.87 0.00 0.00
Travel Time (min) = 0.87 + 0.00 + 0.00 = 0.87
Channel Flow
X sectional flow area (sqft) = 0.50 0.00 0.00
Wetted perimeter (ft) = 1.50 0.00 0.00
Channel slope (%) = 2.00 0.00 0.00
Manning's n-value = 0.013 0.015 0.015
Velocity (ft/s) = 7.76 0.00 0.00
Flow length (ft) = 300.0 0.0 0.0
Travel Time (min) = 0.64 + 0.00 + 0.00 = 0.64
Total Travel Time, Tc .............................. ................................................ 2.50 min
42
(4
Hydrbgraph Plot
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:8 PM
Hyd. No. 3
infiltrate
Hydrograph type = Diversion1 Peak discharge = 15.14 cfs
Storm frequency = 25 yrs Time interval = 1 min
Inflow hydrograph = 2 2nd diverted hyd. = 4
Diversion method = Flow Ratio Flow ratio = 0.58
Hydrograph Volume = 27,214 cuft
infiltrate
Q (cfs) Hyd. No. 3 -- 25 Yr
28.00
24.00
20.00
16.00
12.00
8.00
4.00
Q (cfs)
28.00
24.00
20.00
16.00
12.00
8.00
4.00
0.00 0.00
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0
Hyd No. 3 Hyd No. 2 Hyd No. 4 Time (hrs)
P ". it.
43
Hydrbgraph Plot
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:8 PM
Hyd. No. 4
To detention pond
Hydrograph type = Diversion2 Peak discharge = 10.96 cfs
Storm frequency = 25 yrs Time interval = 1 min
Inflow hydrograph = 2 2nd diverted hyd. = 3
Diversion method = Flow Ratio Flow ratio = 0.58
Hydrograph Volume = 19,707 cuft
To detention pond
Q (cfs) Hyd. No. 4 -- 25 Yr Q (cfs)
28.00 28.00
24.00
20.00
16.00
12.00
8.00
4.00
0.00
0.0
2.0 4.0
Hyd No. 4
24.00
20.00
16.00
12.00
8.00
4.00
0.00
6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0
Time (hrs)
- Hyd No. 2 Hyd No. 3
44
Paw, 11
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:8 PM
Hyd. No. 5
Detention Pond Outlet
Hydrograph type = Reservoir Peak discharge = 8.69 cfs
Storm frequency = 25 yrs Time interval = 1 min
Inflow hyd. No. = 4 Max. Elevation = 488.41 ft
Reservoir name = Detention Pond Max. Storage = 5,127 cuft
Storage Indication method used. Hydrograph Volume = 19,706 cuft
Q (cfs)
12.00
Detention Pond Outlet
Hyd. No. 5 -- 25 Yr Q (cfs)
12.00
10.00
8.00
6.00
4.00
2.00
0.00
0 2 5 7 9
Hyd No. 5 Hyd No. 4
10.00
8.00
6.00
4.00
2.00
0.00
12 14 16 19 21 23 26
Time (hrs)
45
owu
-Pond Report
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:8 PM
Pond No. 1 - Detention Pond
Pond Data
Pond storage is based on known contour areas. Average end area method used.
Stage / Storage Table
Stage (ft) Elevation (ft) Contour area (sgft) Incr. Storage (cuft) Total storage (cuft)
0.00 483.50 00 0 0
1.50 485.00 25 19 19
2.50 486.00 1,202 614 632
4.50 488.00 2,155 3,357 3,989
6.50 490.00 3,334 5,489 9,478
Culvert / Orifice Structures Weir Structures
[A] [B] [C] [D] [A] [I3] [C] [D]
Rise (in) = 18.00 3.60 0.00 0.00 Crest Len (ft) = 9.00 0.00 0.00 0.00
Span (in) = 18.00 3.60 0.00 0.00 Crest El. (ft) = 488.00 0.00 0.00 0.00
No. Barrels = 1 1 0 0 Weir Coeff. = 3.33 3.33 0.00 0.00
Invert El. (ft) = 483.00 483.60 0.00 0.00 Weir Type = Riser --- --- ---
Length (ft) = 70.00 0.00 0.00 0.00 Multi-Stage = Yes No No No
Slope (%) = 2.00 0.00 0.00 0.00
N-Value = .013 .013 .013 .013
Crif. Coeff. = 0.60 0.60 0.60 0.60
Multi-Stage = n/a Yes No No Exfiltration = 0.000 in/hr (Contour) Tai lwater Elev. = 0.00 ft
Note. Culvert/Orifice outflows have been analyzed under inlet and outlet control.
Stage (ft)
7.00
6.00
5.00
4.00
3.00
2.00
1.00
0.00
0.00
Stage / Discharge
46
Stage (ft)
7.00
6.00
5.00
4.00
3.00
2.00
1.00
0.00
22.00
Discharge (cfs)
A"' 1
2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00 20.00
Total Q
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:8 PM
Hyd. No. 6
Post dev not to detention
Hydrograph type = SCS Runoff Peak discharge = 7.44 cfs
Storm frequency = 25 yrs Time interval = 1 min
Drainage area = 2.16 ac Curve number = 63
Basin Slope = 0.0% Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 13.3 min
Total precip. = 6.41 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Hydrograph Volume = 19,044 cuft
Q (cfs)
8.00
6.00
4.00
2.00
0.00
0
2 5
Hyd No. 6
Post dev not to detention
Hyd. No. 6 -- 25 Yr
7 9 12 14 16
19 21
Q (cfs)
8.00
6.00
4.00
2.00
0.00
23 26
Time (hrs)
47
pa'?v ? b
"TR55 Tc Worksheet
Hydraflow Hydrographs by Intelisolve
Hyd. No. 6
Post dev not to detention
Description A B C Totals
Sheet Flow
Manning's n-value = 0.240 0.011 0.011
Flow length (ft) = 100.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.60 0.00 0.00
Land slope (%) = 3.00 0.00 0.00
Travel Time (min) = 11.44 + 0.00 + 0.00 = 11.44
Shallow Concentrated Flow
Flow length (ft) = 150.00 0.00 0.00
Watercourse slope (%) = 3.00 0.00 0.00
Surface description = Unpaved Paved Paved
Average velocity (ft/s) = 2.79 0.00 0.00
Travel Time (min) = 0.89 + 0.00 + 0.00 = 0.89
Channel Flow
X sectional flow area (sqft) = 0.50 0.00 0.00
Wetted perimeter (ft) = 1.50 0.00 0.00
Channel slope (%) = 3.00 0.00 0.00
Manning's n-value = 0.025 0.015 0.015
Velocity (ft/s) = 4.94 0.00 0.00
Flow length (ft) = 300.0 0.0 0.0
48
Travel Time (min) = 1.01 + 0.00 + 0.00 = 1.01
Total Travel Time, Tc .............................................................................. 13.30 min
Hydtograph Plot
Hydraflow Hydrographs by Intelisolve
Hyd. No. 7
Post Dev. Total
Hydrograph type = Combine
Storm frequency = 25 yrs
Inflow hyds. = 5, 6
Friday, Apr 25 2008, 5:8 PM
Peak discharge = 15.14 cfs
Time interval = 1 min
Hydrograph Volume = 38,751 cuft
Q (cfs)
18.00
Post Dev. Total
Hyd. No. 7 -- 25 Yr Q (cfs)
18.00
15.00
12.00
9.00
6.00
3.00
0.00
0 2 5 7 9
Hyd No. 7 Hyd No. 5
15.00
12.00
9.00
6.00
3.00
0.00
12 14 16 19 21 23 26
Hyd No. 6 Time (hrs)
49
pao? ? d-
50
Hydrograph Summary Report
Hyd.
No. Hydrograph
type
(origin) Peak
flow
(cfs) Time
interval
(min) Time to
peak
(min) Volume

(cuft) Inflow
hyd(s) Maximum
elevation
(ft) Maximum
storage
(cuft) Hydrograph
description
1 SCS Runoff 27.40 1 721 69,679 ---- ------ ------ Pre Dev.
2 SCS Runoff 35.47 1 715 64,770 ---- ------ ------ Post dev to Det. Pond
3 Diversion1 20.58 1 715 37,567 2 ------ ------ infiltrate
4 Diversion2 14.90 1 715 27,204 2 ------ ------ To detention pond
5 Reservoir 13.77 1 717 27,203 4 488.58 5,579 Detention Pond Outlet
6 SCS Runoff 11.19 1 721 28,316 ---- ------ ------ Post dev not to detention
7 Combine 22.89 1 717 55,519 5,6 ------ ------ Post Dev. Total
i
I
13037 detention rev 4-25-08.gpw Return Period: 100 Year Friday, Apr 25 2008, 5:08 PM
Hydraflow Hydrographs y Intelisolve
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:8 PM
Hyd. No. 1
Pre Dev.
Hydrograph type = SCS Runoff Peak discharge = 27.40 cfs
Storm frequency = 100 yrs Time interval = 1 min
Drainage area = 5.85 ac Curve number = 60
Basin Slope = 0.0% Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 13.3 min
Total precip. = 8.00 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Hydrograph Volume = 69,679 cuft
Q (cfs)
28.00
24.00
20.00
16.00
12.00
8.00
4.00
Q (cfs)
28.00
24.00
20.00
16.00
12.00
8.00
4.00
0.00 0.00
0 2 5 7 9 12 14 16 19 21 23 26
Hyd No. 1 Time (hrs)
51
?"t o
Pre Dev.
Hyd. No. 1 -- 100 Yr
'TR55 Tc Worksheet
Hydraflow Hydrographs by Intelisolve
Hyd. No. 1
Pre Dev.
Description A B C Totals
Sheet Flow
Manning's n-value = 0.240 0.011 0.011
Flow length (ft) = 100.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.60 0.00 0.00
Land slope (%) = 3.00 0.00 0.00
Travel Time (min) = 11.44 + 0.00 + 0.00 = 11.44
Shallow Concentrated Flow
Flow length (ft) = 150.00 0.00 0.00
Watercourse slope (%) = 3.00 0.00 0.00
Surface description = Unpaved Paved Paved
Average velocity (ft/s) = 2.79 0.00 0.00
Travel Time (min) = 0.89 + 0.00 + 0.00 = 0.89
Channel Flow
X sectional flow area (sqft) = 0.50 0.00 0.00
Wetted perimeter (ft) = 1.50 0.00 0.00
Channel slope (%) = 3.00 0.00 0.00
Manning's n-value = 0.025 0.015 0.015
Velocity (ft/s) = 4.94 0.00 0.00
Flow length (ft) = 300.0 0.0 0.0
Travel Time (min) = 1.01 + 0.00 + 0.00 = 1.01
Total Travel Time, Tc .............................................................................. 13.30 min
52
PAP,t ? S
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:8 PM
Hyd. No. 2
Post dev to Det. P ond
Hydrograph type = SCS Runoff Peak discharge = 35.47 cfs
Storm frequency = 100 yrs Time interval = 1 min
Drainage area = 3.69 ac Curve number = 76
Basin Slope = 0.0% Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 2.5 min
Total precip. = 8.00 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Hydrograph Volume = 64,770 cuft
Q (cfs)
40.00
30.00
20.00
10.00
0.00
0.0
2.0
Hyd No. 2
Post dev to Det. Pond
Hyd. No. 2 -- 100 Yr
4.0 6.0 8.0
Q (cfs)
40.00
30.00
20.00
10.00
0.00
10.0 12.0 14.0 16.0 18.0 20.0
Time (hrs)
53
PW ae
TR55 Tc Worksheet
54
Hydraflow Hydrographs by Intelisolve
Hyd. No. 2
Post dev to Det. Pond
Description A B C Totals
Sheet Flow
Manning's n-value = 0.011 0.011 0.011
Flow length (ft) = 100.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.60 0.00 0.00
Land slope (%) = 3.00 0.00 0.00
Travel Time (min) = 0.97 + 0.00 + 0.00 = 0.97
Shallow Concentrated Flow
Flow length (ft) = 150.00 0.00 0.00
Watercourse slope (%) = 2.00 0.00 0.00
Surface description = Paved Paved Paved
Average velocity (ft/s) = 2.87 0.00 0.00
Travel Time (min) = 0.87 + 0.00 + 0.00 = 0.87
Channel Flow
X sectional flow area (sqft) = 0.50 0.00 0.00
Wetted perimeter (ft) = 1.50 0.00 0.00
Channel slope (%) = 2.00 0.00 0.00
Manning's n-value = 0.013 0.015 0.015
Velocity (ft/s) = 7.76 0.00 0.00
Flow length (ft) = 300.0 0.0 0.0
Travel Time (min) = 0.64 + 0.00 + 0.00 = 0.64
Total Travel Time, Tc ................................................... ........................... 2.50 min
PO'Ot g?
1
55
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve
Hyd. No. 3
infiltrate
Hydrograph type = Diversion1
Storm frequency = 100 yrs
Inflow hydrograph = 2
Diversion method = Flow Ratio
Q (cfs)
40.00
30.00
20.00
10.00
0.00
0.0
30.00
20.00
10.00
0.00
2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0
Hyd No. 3 Hyd No. 2 Hyd No. 4 Time (hrs)
Friday, Apr 25 2008, 5:8 PM
Peak discharge = 20.58 cfs
Time interval = 1 min
2nd diverted hyd. = 4
Flow ratio = 0.58
Hydrograph Volume = 37,567 cuft
infiltrate
Hyd. No. 3 -- 100 Yr Q (cfs)
40.00
Pte, ?ft
Hydtograph Plot
57
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:8 PM
Hyd. No. 5
Detention Pond Outlet
Hydrograph type = Reservoir Peak discharge = 13.77 cfs
Storm frequency = 100 yrs Time interval = 1 min
Inflow hyd. No. = 4 Max. Elevation = 488.58 ft
Reservoir name = Detention Pond Max. Storage = 5,579 cuft
Storage Indication method used.
Q (cfs)
15.00
12.00
9.00
6.00
3.00
Detention Pond Outlet
Hyd. No. 5 -- 100 Yr
12.00
9.00
6.00
3.00
0.00 0.00
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 22.0
Time (hrs)
Hyd No. 5 Hyd No. 4
Hydrograph Volume = 27,203 cult
Q (cfs)
1. nn

Pond Report
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:8 PM
Pond No. 1 - Detention Pond
Pond Data
Pond storage is based on known contour areas. Average end area method used.
Stage / Storage Table
Stage (ft) Elevation (ft) Contour area (sqft) Incr. Storage (cult) Total storage (cuft)
0.00 483.50 00 0 0
1.50 485.00 25 19 19
2.50 486.00 1,202 614 632
4.50 488.00 2,155 3,357 3,989
6.50 490.00 3,334 5,489 9,478
Culvert / Orifice Structures
[A] [B] [C] [D]
Rise (in) = 18.00 3.60 0.00 0.00
Span (in) = 18.00 3.60 0.00 0.00
No. Barrels = 1 1 0 0
Invert El. (ft) = 483.00 483.60 0.00 0.00
Length (ft) = 70.00 0.00 0.00 0.00
Slope (%) = 2.00 0.00 0.00 0.00
N-Value = .013 .013 .013 .013
Orif. Coeff. = 0.60 0.60 0.60 0.60
Multi-Stage = n/a Yes No No
Weir Structures
[A] [B] [C] [D]
Crest Len (ft) = 9.00 0.00 0.00 0.00
Crest El. (ft) = 488.00 0.00 0.00 0.00
Weir Coeff. = 3.33 3.33 0.00 0.00
Weir Type = Riser --- --- ---
Multi-Stage = Yes No No No
Exfiltration = 0.000 in/hr (Contour) Tailwater Elev. = 0.00 ft
Note' Culvert/Orifice outflows have been analyzed under inlet and outlet control.
Stage (ft)
7.00
6.00
5.00
4.00
3.00
2.00
1.00
0.00
0.00
Stage / Discharge
Stage (ft)
7.00
6.00
5.00
4.00
3.00
2.00
1.00
0.00
22.00
Discharge (cfs)
Am? a
58
2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00 20.00
- - Total Q
Hydeograph Plot
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:8 PM
Hyd. No. 6
Post dev not to detention
Hydrograph type = SCS Runoff Peak discharge = 11.19 cfs
Storm frequency = 100 yrs Time interval = 1 min
Drainage area = 2.16 ac Curve number = 63
Basin Slope = 0.0% Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 13.3 min
Total precip. = 8.00 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Hydrograph Volume = 28,316 cult
Q (cfs)
12.00
10.00
8.00
6.00
4.00
2.00
Post dev not to detention
Hyd. No. 6 -- 100 Yr
0.00
0 2 5
Hyd No. 6
Q (cfs)
12.00
10.00
8.00
6.00
4.00
2.00
0.00
7 9 12 14 16 19 21 23 26
Time (hrs)
59
P"', 9 ?-
TR55 Tc Worksheet
Hydraflow Hydrographs by Intelisolve
Hyd. No. 6
Post dev not to detention
Description A B C Totals
Sheet Flow
Manning's n-value = 0.240 0.011 0.011
Flow length (ft) = 100.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.60 0.00 0.00
Land slope (%) = 3.00 0.00 0.00
Travel Time (min) = 11.44 + 0.00 + 0.00 = 11.44
Shallow Concentrated Flow
Flow length (ft) = 150.00 0.00 0.00
Watercourse slope (%) = 3.00 0.00 0.00
Surface description = Unpaved Paved Paved
Average velocity (ft/s) = 2.79 0.00 0.00
Travel Time (min) = 0.89 + 0.00 + 0.00 = 0.89
Channel Flow
X sectional flow area (sqft) = 0.50 0.00 0.00
Wetted perimeter (ft) = 1.50 0.00 0.00
Channel slope (%) = 3.00 0.00 0.00
Manning's n-value = 0.025 0.015 0.015
Velocity (ft/s) = 4.94 0.00 0.00
Flow length (ft) = 300.0 0.0 0.0
Travel Time (min) = 1.01 + 0.00 + 0.00 = 1.01
Total Travel Time, Tc .............................................................................. 13.30 min
60
Pal q3
Hydtograph Plot
Hydraflow Hydrographs by Intelisolve Friday, Apr 25 2008, 5:8 PM
Hyd. No. 7
Post Dev. Total
Hydrograph type = Combine Peak discharge = 22.89 cfs
Storm frequency = 100 yrs Time interval = 1 min
Inflow hyds. = 5, 6
Hydrograph Volume = 55,519 cuft
Post Dev. Total
Q (cfs) Hyd. No. 7 -- 100 Yr
24.00
20.00
16.00
12.00
8.00
4.00
0.00
0 2 5 7 9
Hyd No. 7 Hyd No. 5
Q (cfs)
24.00
20.00
16.00
12.00
8.00
4.00
61
0.00
12 14 16 19 21 23 26
Hyd No. 6 Time (hrs)
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Operation and Maintenance Plan for BMPs
(Under revision, to be provided at a later date)
Dnno ja /
DEVELOPMENT IN THE RESOURCE CONSERVATION
DISTRICT AREA
FOR
ORANGE COUNTY ANIMAL SERVICES
ona o Q
Development in the Resource Conservation District (RCD)
Project Name:
Project Number:
Report Date:
Project Location:
Purpose:
A. Utilities Plan:
Orange County Animal Services
13037
March 16, 2007, revised May 7, 2007, revised November 15,
2007; Revised April 25, 2008
Eubanks Road, Chapel Hill, Orange County
Describe development activities for the project and identify
potential impacts, due to development in the RCD
(Utilities Plan is provided in the drawing package).
B. Grading Plan showing existing and final contours:
(Grading plan is provided in the drawing package).
C. Sedimentation and Erosion Control Plan:
Erosion control plans have been prepared in accordance with the guidance
contained in North Carolina Erosion and Sediment Control Planning and Design
Manual, 2006 Revisions, and requirements of the Town of Chapel Hill and
submitted to the Raleigh Regional Office of the NC Land Quality Section for
review and approval. Typical erosion control devices such as diversion berms,
drainage channels, sediment traps and/or sediment basins are employed in the
design and plan. Financial Responsibility Forms have been executed and
submitted with the plan to the Land Quality Section.
D. Stormwater Management Plan:
Attached.
E. Soils Analysis:
Soils on site are mostly of the Georgeville type with some small area of Tatum
type (both are Hydrologic Group B), based upon the Orange County Soils
Survey. Silt loam and well-drained are general characteristics used to describe
these soil types.
F. Plan view of the development project:
(Plan view provided in the drawing package).
G. Profile view of watercourse bed, etc:
Attached.
H. Existing Vegetation and landscape plan:
(Existing vegetation is shown on plans. Landscape plan is included in the
drawing package).
1. Description of wildlife habitat:
The existing site is primarily covered in scrub vegetation and provides habitat for
small animals (rabbits, foxes, rodents) and birds.
J. Storage of materials and waste disposal:
There will be no storage of materials or waste disposal in the RCD.
K. Floodproofing:
Not applicable. There are no buildings located in the RCD.
L. Alteration or relocation of riverine watercourse:
There will be an extension of the existing culvert and improvement of the outlet
protection for the off-site perennial stream on each side of Eubanks Road to
accommodate the pavement widening of Eubanks Road. Channel re-alignment
of the stream necessary to accommodate the culvert extension is proposed. The
design of this re-alignment will minimize the impacts to the stream channel.
M. Elevation of the 100-year flood upstream from the development:
Due to the controls that are established for stormwater runoff management,
treatment and control for the development, the logical conclusion is that the
elevation of the 100 year flood will not be altered as a result of this development.
N. List of owners within 500 feet, with stamped, pre-addressed envelopes:
Attached.
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JOB yr_kA P. 0. 4141%1, Am /A21 '5e
v 7- 1
CIVIL CONSULTANTS, INC. SHEET NO. OF
3708 Lyckan Parkway Suite 201 CALCULATED BY DATE 3??•Zs07'
DURHAM, NC 27707
[phone] CHECKED BY DATE
Fax [phone]
SCALE
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