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CONSERVATION OVERLAY SIDEWALK
DISTRICT (COD)
F•
COD SETBACK — — — — PHASE I BOUNDARY
— • — • — • — • DRAINAGE PIPE
RESOURCE PRESERVATION '' - - - DRAINAGE SWALE
AREA FOR MITIGATION
WOODLINE
TEMPORARY GRAVEL
TURNAROUND
PROPOSED BUILT UPON AREA (PHASE
BUILDINGS:
PICNIC SHELTER: 1,800 SF
RESTROOM/CONCESSION: 1,890 S
RESTROOM/VENDING: 915 SF
MAINTENANCE BUILDING: 4,200 S
(5) SCORING BOOTHS: 400 SF
TOTAL BUILDINGS: 9,205
STREETS: 51,526 SF
PARKING: 92,212 SF
EMERGENGY GRAVEL ACCESS: 24,115 S
SIDEWALKS AND PATHS: 34,855 SF
OTHER BUA:
PLAYGROUND: 24,731 SF
MIRACLE FIELD: 25,587 SF
TOTAL OTHER BUA: 50,318 SF
TOTAL PROPOSED BUA: 262,231 SF
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WETLANDS: 176,766 SF
F COASTAL WETLANDS: 0 SF
UPLAND: 3,716,363 SF ♦ . / j� •
F *PERMIT AREA FOR DENSITY: 3,893,129 SF PERMIT AREA / l j / t f% `/lf �1/ Q
EXISTING IMPERVIOUS: 0 SF%� (11 Cj
PROPOSED PERCENT IMPERVIOUS: 6.7% coy")/j1'
* PERMIT AREA = OVERALL PARCEL — COASTAL WETLANDS
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NEW HANOVER COUNTY
BOARD OF EDUCATION
R03400-002-003-000
D.B. 1030 PG. 0616
UVtKALL SI I t FLAN
FOR
OLSEN PARK - PHASE 1
NEW HANOVER COUNTY NORTH CAROLINA
PREPARED FOR
THE CITY OF WILMINGTON
320 CHESTNUT STREET
P.O. BOX 1810
WILMINGTON, NORTH CAROLINA 28402-1810
,00 [phone]
FEBRUARY 20, 2009
REVISED: MAY 5, 2009

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028179
v9 INE;:�'�,�
BY:
OLSEN PARK - PHASE 1
NEW HANOVER COUNTY, NORTH CAROLINA
STORMWATER DESIGN
CONSIDERATIONS
PREPARED FOR
THF. CITY OF WILMINGTON
DECEMBER 4, 2008
REVISED: FEBRUARY 23, 2009
FEB 2 4 2009
20050.406
T HomAs & Hf ri oN ENGINEERING CO.
WILMINGTON, NORTH CAROLINA
SAVANNAH, GEORGIA
CHARLESTON, SOUTH CAROLINA
MYRTLE BEACH, SOUTH CAROLINA
BRUNSWICK, GEORGIA

TABLE OF CONTENTS
LOCATIONMAP................................................................................................. 8 1/2" x I I" map
SECTION 1— Project Narrative
SECTION 2 — Pond Routing
Purpose
Proposed Drainage System
Stormwater Quantity Methodology
Hydrology
Conclusions
Summary of Results
2.1 Time of Concentration and Curve Number Calculations
2.2 Pre -Development ICPR Model Inputs and Results
2.3 Post Development ICPR Model Inputs and Results
2.4 Combined Unit Hydrograph Calculations
2.5 Pre and Post Development Drainage Area Exhibits (24" x 36")
Overall Site Plan Exhibit (24" x 36")
SECTION 3 — Wetland Crossing Calculations
3.1 Stream Crossing Drainage Calculations
3.2 Culvert Design Considerations
3.3 Wetland Pipe Crossing Exhibit (24" x 36")
SECTION 4 — State Stormwater, Sediment and Erosion Control Calculations
4.1 Grassed Swale Design Calculations
4.2 Sediment Trap Design Considerations
4.3 Level Spreader Design Considerations
SECTION 5 — NHC Stormwater, Sediment and Erosion Control Calculations
5.1 Grassed Swale Design Calculations
5.2 Culvert and Rip Rap Outlet Design Considerations
Revision Summary:
2-23-09 -- Revised per NCDENR DWQ comments dated 2-13-09.
N:\20050\Dsgn\Stormwater\20050 Stormwater Report.doc

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PROJECT NARRATIVE
Olsen Park - Phase 1 is a 52.23 acre proposed low -density community park
consisting of five (5) multi -purpose softball fields and is located on the south side
of Interstate 40. The Phase 1 entrance will be located at the end of Corporate
Drive (SR 2653). From aerial photo and field survey, the existing site conditions
may be classified as fairly wooded or fair pasture lands. The existing topography
is relatively flat with slopes ranging from 0-10%. The Pre -development runoff
drains via overland flow to the ditch that runs along property boundary and to the
various ditches along the perimeter of the property before ultimately reaching
Smith Creek approximately 0.50 mile away. Smith Creek is classified as C;Sw
waters and the stream index number is 18-74-63. The soils on site are classified
as hydrologic soil groups "A", "A/D", `B", "C", "D" and `B/D".
Phase 1 of the proposed low -density community park project will ultimately
consist of five (5) multi -purpose softball fields, roads, utilities, impervious field
intended for "disabled" use, impervious playground area, and structures that will
not exceed 24% impervious area of the Phase 1 site. Site structures include
restroom/vending building, restroom/concession building, picnic shelter,
maintenance building, scoring buildings, dugouts, and bleacher stand concrete
pads. Site development will include new roads, parking, sidewalks, stormwater,
and water and sewer infrastructure to serve the site appurtenances. The post
development runoff will be treated by vegetative swales and collection basins.
The project has been designed to meet the requirements of "low density"
according to the state Coastal Stormwater Rules. The higher density has been
located in upland areas and away from surface waters and drainage ways to the
maximum extent practicable. In determination of "maximum extent practicable",
consideration was given to the following:
A. Protection of existing vegetation on the site is of great importance to this
project as the land plan was designed around preserving the wooded area
located in the uplands on the northeast of the site. By nature of the use of
this project as a public park, the impervious surfaces are clustered
according to low impact development practices which also allows for ease
of accessibility by the public from the parking areas to the recreational
uses. The parking area was located as far as practicable from the
drainageway while preserving the trees and allowing five fields to fit the
site.
B. The project is designed with a low density approach of minimizing pipe
and curbs and maximizing vegetative conveyances to treat the runoff
before it is discharged to the drainageway, or the ditch on the southern
portion of the tract. The runoff not proposed to flow directly to one of the
basins is generally routed overland or through increased lengths of
vegetative swales.

Drainage pipes and energy dissipater were designed to the 25-year storm event
per New Hanover County Stormwater Ordinance. Pipe capacity and Energy and
Dissipater Calculations can be found in Section 5.2.
Erosion control devices will consist of temporary silt fencing, grassing, sediment
filters and energy dissipaters at outlets and areas of concentrated flows. The
anticipated construction sequence is as follows:
1. Install silt fence and tree protection;
2. Clearing;
3. Install remaining erosion control measures;
4. Install detention basin (sediment basin);
5. Install drainage conveyances including stone check dams;
6. Site rough grading;
7. Install sewer system;
8. Install water system;
9. Roads and final grading; and
10. Final grassing and stabilization. Restore all drainage conveyances to
design specifications upon project completion.

PURPOSE
• To define the limits of the drainage basin or basins that comprises this project.
• To document compliance with regulatory requirements of the State of North Carolina and
New Hanover County specific to this project, summarized as follows:
o North Carolina Department of Natural Resources
➢ Impervious surface will not exceed 24% of the total site acreage.
➢ For a low density project, maintain a minimum 100' length in the vegetative
swales.
➢ Design swales for the 10-year storm and ensure peak flow is non -erosive.
o New Hanover County
➢ Post -development peak run-off rate for the 2, 10 and 25-year storms must be
equal or less than pre -development run-off rates.
➢ Detention basin shall be designed to accommodate the 25-year storm event.
■ Analyze 100-year storm event stage in detention basins
PROPOSED DRAINAGE SYSTEM
The components of the proposed system are vegetative swales and collection basins. Runoff
from the built upon area will be directed to the vegetated swales and/or existing ditches via sheet
flow. The swales are designed to convey post development runoff to the same pre -development
outfall.
STORMWATER QUANTITY METHODOLOGY
The existing and proposed conditions will be analyzed using the Advanced Interconnected
Channel and Pond Routing (ICPR) computer program developed by Streamline Technologies.
The program is used to model rainfall and storm water runoff and to perform hydraulic routing
through the storm drainage system. The ICPR program is a FEMA approved model that has the
ability to analyze complex interconnected drainage systems dynamically over extended time
periods.
The hydrologic input data consists of information for each drainage basin, or subwatershed,
within the project. Input variables include runoff curve number, rainfall distribution pattern,
hydrograph peaking factor, area of each drainage basin, and time of concentration (see below
section "Hydrology" for specifics on the values of these variables that were used in this model).
The ICPR program generates runoff hydrographs for each subwatershed based on the user -
specified variables. Hydrographs are generated by ICPR using the SCS Unit Hydrograph
Method.
NA20050\Dsgn\Stormwater\20050 Stormwater Repoil.doc

The model hydraulic input data consists of a system of nodes and links. Nodes represent
locations where flows enter or exit the system, pipe or channel characteristics change, or where
stage/storage/time relationships are provided. Links represent traditional types of hydraulic
conveyance such as pipes, channels, drop structures, weirs, etc. The sizes, inverts, lengths, and
Manning n values for all pipes connecting the lagoons are input into the model. In addition to pipe
information, all lagoon and detention area stage -storage information and the respective outfall
structure information is input into the model. The node and link conditions are analyzed within
the model for a given storm, and flow conditions are determined.
The basic equation used by ICPR to route flows through the system is:
As= (Qin - Qout) At
Where:
Change in storage for time step = As
Flow into a node at time "t" _
Qin
Flow out of a node at time "t" _
Qout
Length of time step; user defined range from 1.0 sec to 0.1 sec. = At
Hydrographs for each drainage area are merged within the ICPR program, and the hydrologic
results are then combined with the hydraulic information to model the hydraulic interactions of
the entire drainage system. The results include lagoon and detention area discharge rates and
stage/storage information during the design storm.
For the design of the storm drainage system, a warning stage elevation is set for each lagoon and
detention area and structure to assure no storm water ponding. In addition, the ultimate discharge
rate from the system cannot exceed the pre -developed runoff rate. Knowing these two factors, the
drainage system is designed by trial and error.
HYDROLOGY
SCS Unit Hydrograph Method is used. SCS 484 Hydrograph Peaking Factor is used for
developed basins as specified in the New Hanover County Stormwater Design Manual.
Amount of rainfall for each storm frequency is determined based on National Oceanic
and Atmospheric Administration (NOAA) Atlas 14 (Volume 2; 2004). The following
design storms are used in the model simulations:
- 2-year, 24-hour Design Storm = 4.67 inches
- 10-year, 24-hour Design Storm = 7.25 inches
- 25-year, 24-hour Design Storm = 9.11 inches
- 100-year, 24-hour Design Storm = 12.65 inches
• SCS Type III Statistical Rainfall Distribution is used. This distribution pattern is
determined by the Soil Conservation Service comparing regional rain -gage data.
NA200501Dsgn\Stormwater120050 Stormwater Report.doe

CONCLUSIONS
The proposed drainage system meets the criteria set forth by the Local and State requirements.
SUMMARY OF RESULTS
This project has been designed to meet the minimum requirements of the New Hanover County
Storm Water Design Manual and the State of North Carolina Department of Natural Resources.
The existing and proposed hydrology conditions were analyzed using the Advanced
Interconnected Channel and Pond Routing (ICPR) version 3 computer program developed by
Streamline Technologies. The post -development runoff rates are approximately equal to or less
than the pre -development rates for the 2, 10 and 25-year storms. The 100-year storm event was
analyzed to ensure no structures are flooded. Reference Section 4.1 for compliance with
NCDENR Water Quality requirements.
Storm
Pre -Development
Post -Development
Frequency
Runoff Rates
Discharge Rates
2-Year
64.01 cfs
50.45 cfs
10-Year
136.18 cfs
103.32 cfs
25-Year
191.24 cfs
142.73 cfs
100-Year
298.17 cfs
240.54 cfs
WATER QUALITY
The project is a low density community park that utilizes vegetative conveyance swales with a
minimum length of one -hundred (100) if per North Carolina Department of Natural Resources
regulations for water quality purposes. Reference Section 4.1 of this report.
N:\20050\Dsgn\Stormwater\20050 Stormwater Report.doc

I
O ePn Pa._Tel a �e,e 1
New Hanover County, North Carolina
Section 2.1
Time of Concentration and Curve Number Calculations
Prepared By
Thomas & Hutton Engineering Co.
219 Station Rd. / Wilmington / NC / 28405
50 Park of Commerce Way / Savannah / GA / 31405
935 Houston Northcutt Blvd. / Mt. Pleasant / SC / 29464
1350 Farrow Pkwy / Myrtle Beach / SC / 29577
116 West Palm Plaza Drive / Brunswick / GA / 31523
J-20050

CAM J-20050.404
STORMWATER
STORM WATER DESIGN CONSIDERATIONS
OLSEN PARK - PHASE 1
PREPARED BY: 1 nomas and Hutton Engineering Company
DATE: December 4, 2008
REVISED:
PRE -DEVELOPMENT DRAINAGE CALCULATIONS
BASIN Pre-1
Calculate Time of Concentration
Use Travel Time Concept:
Overland Flow: t =(0.007(nrp^0.8)/((P�^0.5)*(S^0.4)) TR-55 Eq 3-3
where: t = Travel Time for Overland Flow (min)
n = Manning's Coefficient - from TR-55 Table 3-1
1= Length of Flow (ft)
P, = 2-yr Rainfall Depth (in)
S = Hydraulic Slope (ft/ft)
n = 0.40 woods (light underbrush)
I = 100 ft
PZ = 4.5 in
S = 0.010 ft/ft
t = 23.9 min
Shallow Concentrated Flow: t=1/60v
where: t = Travel Time for Shallow Concentrated Flow (min)
1 = Length of Flow (ft)
S = Average Watercourse Slope (ft/ft)
v = Velocity (ft/s)- From TR-55
l = 1000.00 ft
S = 0.020 Unpaved
v = 2.28 ft/s
t = 7.30 min
Therefore, Tc = 31.2 min
Determine Composite CN Value from TR-55 Table 2-2
Description
HSC
CN
A (ac)
CN x A
Pasture (Fair)
A
49
4.22
206.78
Woods (Fair)
A/D
79
2.88
227.52
Pasture (Fair)
B
69
10.53
726.57
Woods (Fair)
B
60
10.98
658.8
Woods (Fair)
B/D
79
3.77
297.83
Pasture (Fair)
C
79
3.18
251.22
Woods (Fair)
C
73
4.69
342.37
Pasture (Fair)
D
84
6.01
504.84
Woods (Fair)
D
79
5.97
471.63
52.23
3687.56
Composite CN Value =
71
N:1200501DsgnlStormwaterk20050 Tc&CN 2-18-09 TEST.xls

I CAM
J-20050.404
I
STORMWATER
STORM WATER DESIGN CONSIDERATIONS
Olsen Park - Phase 1
PREPARED BY: Thomas & Hutton Engineering Co.
DATE: December 4, 2008
REVISED:
POST DEVELOPMENT DRAINAGE CALCULATIONS
B-SWALE 2
Calculate Time of Concentration
Use Travel Time Concept:
Overland Flow: t =(0.007(n*l)^0.8)/((P,A0.5)*(S^0.4)) TR-55 Eq 3-3
where: t = Travel Time for Overland Flow (min)
n = Manning's Coefficient - from TR-55 Table 3-1
1= Length of Flow (ft)
P, = 2-yr Rainfall Depth (in)
S = Hydraulic Slope (ft/ft)
n = 0.41 Bermuda
I = 100 ft
P, = 4.5 in
S = 0.010 ft/ft
t = 24.4 min
Shallow Concentrated Flow: t=1/60v
where: t = Travel Time for Shallow Concentrated Flow (min)
I = Length of Flow (ft)
S = Average Watercourse Slope (ft/ft)
v = Velocity (ft/s)- From TR-55
I = 340.00 ft
S = 0.010 Unpaved
v - 1.61 ft/s
t = 3.51 min
Therefore, Tc = 27.9 min
Determine Composite CN Value from TR-55 Table 2-2
Description
HSG
CN
A (ac)
CN x A
Impervious
98
0.88
86.24
Open Space (Fair)
A
49
0. i i
5.39
Open Space (Fair)
B
69
1.44
99.36
Woods (Fair)
B
60
0.55
33.00
Composite CN Value = 75
2.98 223.99
LN:1200501DsgnlStormwater120050 Tc&CN 2-18-09 TEST.xls

rCAM J-20050.404
I^ POST DEVELOPMENT DRAINAGE CALCULATIONS
B-SWALE 1
I
Calculate Time of Concentration
Use Travel Time Concept:
Overland Flow: t =(0.007(n*I)^0.8)/((P,^0.5)*(S"0.4)) TR-55 Eq 3-3
where: t = Travel Time for Overland Flow (min)
n = Manning's Coefficient - from TR-55 Table 3-1
1 = Length of Flow (ft)
P, = 2-yr Rainfall Depth (in)
S = Hydraulic Slope (ft/ft)
n = 0.41 Bermuda
1 I = 100 ft
Pz = 4.5 in
S = 0.010 ft/ft
t = 24A min
Shallow Concentrated Flow: t=1/60v
where: t = Travel Time for Shallow Concentrated Flow (min)
l = Length of Flow (ft)
' S = Average Watercourse Slope (ft/ft)
v = Velocity (ft/s) - From TR-55
I = 1000.00 ft
S = 0.010 Unpaved
v = 1.61 ft/s
t = 10.33 min
1 Therefore, Tc = 34.7
min
Determine Composite CN Value from TR-55 Table 2-2
Description HSG CN
A (ac)
CN x A
Impervious 98
0.15
14.70
Open Space (Fair) A 49
3.75
183.75
Open Space (Fair) B 69
0.15
10.35
Open Space (Fair) C 79
1.28
101.12
Open Space (Fair) D 84
1.17
98.28
6.50
408.20
Composite CN Value = 63
I
i
L
S N:\20050\Dsgn\Stormwater\20050 Tc&CN 2-18-09 TEST.xls

CAM J-20050.404
I POST DEVELOPMENT DRAINAGE CALCULATIONS 7771
B-POND #2
Calculate Time of Concentration
Use Travel Time Concept:
Overland Flow: t =(0.007(n81)^0.8)/((P,10.5)*(S^0.4)) TR-55 Eq 3-3
where: t = Travel Time for Overland Flow (min)
n = Manning's Coefficient - from TR-55 Table 3-1
l = Length of Flow (ft)
P, = 2-yr Rainfall Depth (in)
S = Hydraulic Slope (ft/ft)
n = 0.41 Bermuda
f 1= 100 ft
1 P, = 4.5 in
S = 0.010 ft/ft
t = 24.4 min
Shallow Concentrated Flow: t=1/60v
where: t = Travel Time for Shallow Concentrated
Flow (min)
1= Length of Flow (ft)
S = Average Watercourse Slope (ft/ft)
v = Velocity (ft/s)- From TR-55
1 = 412.00 ft
S = 0.010 Unpaved
v = 1.61 ft/s
t = 4.26 min
Therefore, Tc = 28.6
min
Determine Composite CN Value from TR-55 Table 2-2
Description HSG CN
A (ac)
CN x A
Pond 100
0.43
43.00
Impervious 98
0.93
91.14
I Open Space (Fair) B 69
3.10
213.90
Open Space (Fair) D 84
0.23
19.32
4.69
367.36
Composite CN Value = 78
A
J N:\20050\Dsgn\Stormwater\20050 Tc&CN 2-18-09 TEST.xls

ICAM J-20050.404
POST DEVELOPMENT DRAINAGE CALCULATIONS
B-POND #3
Calculate Time of Concentration
Use Travel Time Concept:
Overland Flow: t =(0.007(n*p^0.8)/((P�^0.5)*(S"0.4)) TR-55 Eq 3-3
where: t = Travel Time for Overland Flow (min)
n = Manning's Coefficient - from TR-55 Table 3-1
1 = Length of Flow (ft)
P, = 2-yr Rainfall Depth (in)
S = Hydraulic Slope (ft/ft)
n = 0.41 Bermuda
I = 100 ft
P, = 4.5 in
S = 0.010 ft/ft
t = 24.4 min
Shallow Concentrated Flow: t=1/60v
where: t = Travel Time for Shallow Concentrated Flow (min)
I = Length of Flow (ft)
S = Average Watercourse Slope (ft/ft)
v = Velocity (ft/s)- From TR-55
1= 381.00 ft
S = 0.010 Unpaved
v = 1.61 ft/s
t = 3.94 min
Therefore, Tc = 28.3 min
Determine Composite CN Value from TR-55 Table 2-2
Description
HSG
CN
A (ac)
CN x A
Pond
100
0.36
36.00
Impervious
-
98
1.32
129.36
Open Space (Fair)
A
49
0.10
4.90
Open Space (Fair)
B
69
2.05
141.45
Open Space (Fair)
C
79
0.02
1.58
Open Space (Fair)
D
84
0.58
48.72
4.43
362.01
Composite CN Value =
82
N:\20050\Dsgn\Stormwater\20050 Tc&CN 2-18-09 TEST.xls

ICAM J-20050.404
r
1 POST DEVELOPMENT DRAINAGE CALCULATIONS
B-DD1
i
' Calculate Time of Concentration
Use Travel Time Concept:
Overland Flow: t =(0.007(n"I)^0.8)/((P,^0.5)*(S^0.4)) TR-55 Eq 3-3
where: t = Travel Time for Overland Flow (min)
n = Manning's Coefficient - from TR-55 Table 3-1
1 = Length of Flow (ft)
I P, = 2-yr Rainfall Depth (in)
S = Hydraulic Slope (ft/ft)
n = 0.41 Bermuda
I = 100 ft
P, = 4.5 in
S = 0.010 ft/ft
t = 24.4 min
t
i Shallow Concentrated Flow: t=1/60v
where: t = Travel Time for Shallow Concentrated Flow (min)
= Length of Flow (ft)
f S = Average Watercourse Slope (ft/ft)
. v = Velocity (ft/s)- From TR-55
I = 850.00 ft
S = 0.010 Unpaved
I v = 1.61 ft/s
t = 8.78 min
Therefore, Tc = 33.2 min
Determine Composite CN Value from TR-55 Table 2-2
Description HSG CN A (ac)
CN x A
Impervious 98 0.40
39.20
Open Space (Fair) B 69 3.28
226.32
' Open Space (Fair) D 84 3.46
290.64
Woods (Fair) A 36 0.56
20.16
Woods (Fair) B 60 0.32
19.20
8.02 595.52
Composite CN Value = 74
N:\20050\Dsgn\Stormwater\20050 Tc&CN 2-18-09 TEST.xls

CAM J-20050.404
!I-
I
POST DEVELOPMENT DRAINAGE CALCULATIONS
B-DD2
Calculate Time of Concentration
Use Travel Time Concept:
Overland Flow: t = (0.007(nl:I)^0.8)/((P,^0.5)(S^0. )) TR-55 Eq 3-3
f
where: t = Travel Time for Overland Flow (min)
n = Manning's Coefficient - from TR-55 Table 3-1
1 = Length of Flow (ft)
P, = 2-yr Rainfall Depth (in)
S = Hydraulic Slope (ft/ft)
n = 0.41 Bermuda
l = 100 ft
P, = 4.5 in
S = 0.017 ft/ft
t = 19.7 min
Shallow Concentrated Flow: t=1/60v
where: t = Travel Time for Shallow Concentrated Flow (min)
I = Length of Flow (ft)
S = Average Watercourse Slope (ft/ft)
v = Velocity (ft/s)- From TR-55
1= 785.00 ft
S = 0.015 Unpaved
v = 1.98 ft/s
t = 6.62 min
t Therefore, Te = 26.3 min
Determine Composite CN Value from TR-55 Table 2-2
Description HSG CN A (L)
CN x A
Impervious 98 0.95
93.10
I( Open Space (Fair) A 49 0.11
5.39
Open Space (Fair) B 69 4.81
331.89
Open Space (Fair) D 84 0.03
2.52
[ Woods (Fair) A 36 1.71
61.56
fl Woods (Fair) D 79 2.09
165.11
9.70
659.57
Composite CN Value = 68
N:1200501DsgnlStormwater120050 Tc&CN 2-18-09 TEST.xis

` CAM J-20050.404
f-
I POST DEVELOPMENT DRAINAGE CALCULATIONS
I B-DD3
Calculate Time of Concentration
Use Travel Time Concept:
Overland Flow: t =(0.007(n81)^0.8)/((P,^0.5)'(S^0.4)) TR-55 Eq 3-3
where: t = Travel Time for Overland Flow (min)
n = Manning's Coefficient - from TR-55 Table 3-1
I = Length of Flow (ft)
P, = 2-yr Rainfall Depth (in)
S = Hydraulic Slope (ft/ft)
n = 0.41 Bermuda
I = 100 ft
P, = 4.5 in
S = 0.015 ft/ft
t = 20.7 min
Shallow Concentrated Flow: t=1/60v
where: t = Travel Time for Shallow Concentrated Flow (min)
1 = Length of Flow (ft)
S = Average Watercourse Slope (ft/ft)
v Velocity (ft/s)- From TR-55
1= 700.00 ft
S = 0.010 Unpaved
1.61 ft/s
t = 7.23 min
Therefore, Tc = 28.0 min
Determine Composite CN Value from TR-55 Table 2-2
Description
HSG
CN
A (E)
CN x A
Impervious
98
1.00
98.00
Open Space (Fair)
A
49
0.08
3.92
Open Space (Fair)
B
69
2.06
142.14
Open Space (Fair)
C
79
2.53
199.87
Woods
B
60
2.73
163.80
Woods
C
73
3.97
289.81
12.37
897.54
Composite CN Value =
73
N:\20050\1)sgn\Stormwater\20050 Tc&CN 2-18-09 TEST.xls

CAM
J-20050.404
POST DEVELOPMENT DRAINAGE CALCULATIONS
B-DD4
Calculate Time of Concentration
Use Travel Time Concept:
Overland Flow: t =(0.007(n*I)^0.8)/((P,^0.5)*(S^0.4)) TR-55 Eq 3-3
where: t = Travel Time for Overland Flow (min)
n = Manning's Coefficient - from TR-55 Table 3-1
1 = Length of Flow (ft)
P, = 2-yr Rainfall Depth (in)
S = Hydraulic Slope (ft/ft)
n = 0.41 Bermuda
1 = 100 ft
P, = 4.5 in
S = 0.010 ft/ft
t = 24.4 min
Shallow Concentrated Flow: t=1/60v
where: t = Travel Time for Shallow Concentrated Flow (min)
I = Length of Flow (ft)
S = Average Watercourse Slope (ft/ft)
v = Velocity (ft/s) - From TR-55
1 = 100.00 ft
S = 0.010 Unpaved
v = 1.61 ft/s
t = 1.03 min
Therefore, Tc = 25.4 min
Determine Composite CN Value from TR-55 Table 2-2
Description HSG
CN
A (ac)
CN x A
Impervious -
98
0.43
42.14
Open Space (Fair) D
84
1.40
117.60
Woods (Fair) D
79
1.71
135.09
3.54
294.83
Composite CN Value =
83
N:\20050\Dsgn\Stormwater\20050 Tc&CN 2-18-09 TEST.xls

r=

r
Olsen Park - Phase 1
New Hanover County, North Carolina
Section 2.2
Pre -Development ICPR Model Inputs and Results
Prepared By
Thomas & Hutton Engineering Co.
219 Station Rd. / Wilmington / NC / 28405
50 Park of Commerce Way / Savannah / GA / 31405
935 Houston Northcutt Blvd. / Mt. Pleasant / SC / 29464
1350 Farrow Pkwy / Myrtle Beach / SC / 29577
116 West Palm Plaza Drive / Brunswick / GA / 31523
J-20050

Olsen Park - Phase 1
Pre -Development
z/15/2009
...+.+... .+++..++++. NODE DIAGRAM
Nodes
A Stage/Area
V Stage/Volume
T Time/Stage
M Manhole
Basins
O Overland Flow
U SCS Unit CN
S SBUH CN
Y SCS Unit GA
Z SBUH GA
Links
P Pipe
W Weir
C Channel
D Drop Structure
B Bridge
R Rating Curve
H Breach
E Percolation
F Filter
X Exfil Trench
Interconnected Channel and Pond Routing Model (ICPR) 02002 Streamline Technologies, Inc.

e
Olsen Park - Phase 1
Pre -Development
2/19/2009
++r+rrra++++rr++++++ BASIN MAX REPORT **+++++++++rrr+++++a+r
Simulation. Basin Group Time Max Flow Max
hrs cfs
pre002-YR Basin Pre-1 BASE 12.41 64.008
pre010-YR Basin Pre-1 BASE 12.41 136.184
pre025-YR Basin Pre-1 BASE 12.41 191.240
pre100-YR Basin Pre-1 BASE 12.34 298.172
Volume Volume
in ft3
1.868354083.043
3.929744918.890
5.548 +r+rr++++
8.784 ++++rrrrr
Interconnected Channel and Pond Routing Model (ICPR) 02002 Streamline Technologies, Inc.
Page 1 of 1

i
L_

Olsen Park - Phase 1
New Hanover Country, North Carolina
Section 2.3
Post Development ICPR Model Inputs and Results
Prepared By
Thomas & Hutton Engineering Co.
219 Station Rd. / Wilmington / NC / 28405
50 Park of Commerce Way / Savannah / GA / 31405
935 Houston Northcutt Blvd. / Mt. Pleasant / SC / 29464
1350 Farrow Pkwy / Myrtle Beach / SC / 29577
116 West Palm Plaza Drive / Brunswick / GA / 31523
J-20050

I
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N

Olsen Park - Phase 1
Post Development
2/19/2009
INPUT REPORT ++++•++++++.+++•++++:+
Basins = ---=--------------------------------
Name: B-DD1
Node:
BNDY1
Status: Onsite
Group: BASE
Type:
SCS Unit Hydrograph
CN
Unit Hydrograph:
Uh484
Peaking Factor:
484.0
Rainfall File:
Scsiii
Storm Duration(hrs):
24.00
Rainfall Amount(in):
0.000
Time of Conc(min):
33.20
Area(ac):
8.020
Time Shift(hrs):
0.00
Curve Number:
74.00
Max Allowable Q(cfs):
999999.000
DCIA(%):
0.00
----------------------------------------------------------------------------------------------------
Name: B-DD2
Node:
BNDY1
Status: Onsite
Group: BASE
Type:
SCS Unit Hydrograph
CN
Unit Hydrograph: Uh484
Rainfall File: Scsiii
Rainfall Amount(in): 0.000
Area(ac): 9.700
Curve Number: 68.00
DCIA(%): 0.00
Peaking Factor: 484.0
Storm Duration(hrs): 24.00
Time of Conc(min): 26.30
Time Shift(hrs): 0.00
Max Allowable Q(cfs): 999999.000
----------------------------------------------------------------------------------------------------
Name: B-DD3 Node: BNDY2 Status: Onsite
Group: BASE Type: SCS Unit Hydrograph CN
Unit Hydrograph: Uh484
Rainfall File: Scsiii
Rainfall Amount(in): 0.000
Area(ac): 12.370
Curve Number: 73.00
DCIA(%): 0.00
Peaking Factor: 484.0
Storm Duration(hrs): 24.00
Time of Conc(min): 28.00
Time Shift(hrs): 0.00
Max Allowable Q(cfs): 999999.000
------------------------------------------------------ ---------------------------------------------
Name: B-DD4 Node: BNDY1 Status: Onsite
Group: BASE Type: SCS Unit Hydrograph CN
Unit Hydrograph: Uh484
Rainfall File: Scsiii
Rainfall Amount(in): 0.000
Area(ac): 3.540
Curve Number: 83.00
DCIA(%): 0.00
Peaking Factor: 484.0
Storm Duration(hrs): 24.00
Time of Conc(min): 25.40
Time Shift(hrs): 0.00
Max Allowable Q(cfs): 999999.000
----------------------------------------------------------------------------------------------------
Name: B-Pond 2 Node: Pond 2 Status: Onsite
Group: BASE Type: SCS Unit Hydrograph CN
Unit Hydrograph: Uh484
Rainfall File: Scsiii
Rainfall Amount(in): 0.000
Area(ac): 4.690
Curve Number: 78.00
DCIA(%): 0.00
Peaking Factor: 484.0
Storm Duration(hrs): 24.00
Time of Conc(min): 28.60
Time Shift(hrs): 0.00
Max Allowable Q(cfs): 999999.000
-----------------------------------------------------------------------------------------•----------
Name: B-Pond 3
Node: Pond 3
Status: Onsite
Group: BASE
Type: SCS Unit Hydrograph
CN
Unit Hydrograph:
Uh484
Peaking Factor:
484.0
` Rainfall File:
Scsiii
Storm Duration(hrs):
24.00
Rainfall Amount(in):
0.000
Time of Conc(min):
28.30
Area(ac).
4.430
Time Shift(hrs):
0.00
Number:
82.00
Max Allowable Q(cfs):
999999.000
LCurve
DCIA(%) :
0.00
L._
Interconnected Channel and Pond Routing Model (ICPR) 02002 Streamline Technologies, Inc.
Page I of 6
L

Olsen Park - Phase 1
Post Development
2/19/2009
INPUT REPORT ++++++++++++++++++++++
----------------------------------------------------------------------------------------------------
Name: B-SWALE 1 Ncde: SWALE 1 Status: Onsite
Group: BASE Type: SCS Unit Hydrograph CN
Unit Hydrograph: Uh484
Rainfall File: Scsiii
Rainfall Amount(in): 0.000
Area(ac): 6.500
Curve Number: 63.00
DCIA($): 0.00
Peaking Factor: 4B4.0
Storm Duration(hrs): 24.00
Time of Conc(min): 34.70
Time Shift(hrs): 0.00
Max Allowable Q(cfs): 999999.000
----------------------------------------------------------------------------------------------------
Name: B-SWALE 2 Node: BNDY1 Status: Onsite
Group: BASE Type: SCS Unit Hydrograph CN
Unit Hydrograph: Uh484
Rainfall File: Scsiii
Rainfall Amount(in): 0.000
Area (ac) : 2.980
Curve Number: 75.00
DCIA(%): 0.00
Peaking Factor: 484.0
Storm Duration(hrs): 24.00
Time of Conc(min): 27.90
Time Shift(hrs): 0.00
Max Allowable Q(cfs): 999999.000
----------------------------------------------------------------
-----------------------------------------------------
Nodes = --------------------
Name: BNDY1
Group: BASE
Type: Time/Stage
Time(hrs) Stage(ft)
------------------------------
0.00 16.000
24.00 16.000
Base Flow(cfs): 0.000 Init Stage(ft): 16.000
Warn Stage(ft): 18.000
------------------------------------------------------------------------------------------
Name: BNDY2 Base Flow(cfs): 0.000 Init Stage(ft): 34.000
Group: BASE Warn Stage(ft): 37.000
Type: Time/Stage
Time(hrs) Stage(ft)
------------------------------
0.00 34.000
24.00 34.000
------------------------------------------------------------------------------------------
Name: Pond 2 Base Flow(cfs): 0.000 Init Stage(ft): 27.000
Group: BASE Warn Stage(ft): 31.500
Type: Stage/Area
Stage(ft) Area(ac)
------------------------------
27.000 0.2500
31.500 0.4500
------------------------------------------------------ -------------------------------------
Name: Pond 3 Base Flow(cfs): 0.000 Init Stage(ft): 27.000
Group: BASE Warn Stage(ft): 31.500
Type: Stage/Area
Stage(ft) Area(ac)
------------------------------
27.000 0.2300
31.000 0.4600
---------------------------------------------------------------------------------------
Name: SWALE 1 Base Flow(cfs): 0.000 Init Stage(ft): 29.700
Group: BASE Warn Stage(ft): 32.000
Type: Stage/Area
Interconnected Channel and Pond Routing Model (ICPR) ©2002 Streamline Technologies, Inc. Page 2 of 6

Olsen Park - Phase 1
Post Development
2/19/2009
x++++r+r+x+r+++++++a INPUT REPORT *++++xx+xxx+xxxx++xx+x
Stage(ft)
---------------
Area(ac)
---------------
29.700
0.0500
32.000
0.4500
-----------------------------------------------------------
Pipes-----------------------------------------
--------------------------------
Name:
Pond3 -
Pond2 From Node: Pend 3
Length(ft):
179.00
Group:
BASE
To Node: Pond 2
Count:
1
Friction Equation:
Average Conveyance
UPSTREAM
DOWNSTREAM
Solution Algorithm:
Automatic
Geometry:
Circular
Circular
Flow:
Both
Span(in):
30.00
30.00
Entrance Loss Coef:
0.20
Rise(in):
30.00
30.00
Exit Loss Coef:
1.00
Invert(ft):
24.500
24.200
Bend Loss Coef:
0.00
Manning's N:
0.013000
0.013000
outlet Ctrl Spec:
Use do or tw
Top Clip(in):
0.000
0.000
Inlet Ctrl Spec:
Use do
Bot Clip(in):
0.000
0.000
Stabilizer Option:
None
Upstream FHWA Inlet Edge Description:
Circular Concrete: Groove end projecting
Downstream FHWA Inlet Edge Description:
Circular Concrete: Groove end projecting
-------------------------------------------------------------------------------------------
Name:
SW1 - BNDY1
From Node: SWALE 1
Length(ft):
70.00
Group:
BASE
To Node: BNDYl
Count:
1
Friction Equation:
Average Conveyance
UPSTREAM
DOWNSTREAM
Solution Algorithm:
Autnmatir.
Geometry:
Circular
Circular
Flow:
Both
Span(in):
15.00
15.00
Entrance Loss Coef:
0.00
Rise(in):
15.00
15.00
Exit Loss Coef:
0.00
Invert(ft):
29.700
29.500
Bend Loss Coef:
0.00
Manning's N:
0.013000
0.013000
Outlet Ctrl Spec:
Use do or tw
Top Clip(in):
0.000
0.000
Inlet Ctrl Spec:
Use do
Bot Clip(in):
0.000
0.000
Stabilizer Option:
None
Upstream FHWA Inlet Edge Description:
Circular Concrete: Groove end projecting
Downstream FHWA Inlet Edge Description:
Circular Concrete: Groove end projecting
Drop Structures
Name: Pond2 Pond2 - BNDY1
Group: BASE
UPSTREAM
Geometry: Circular
Span(in): 24.00
Rise(in): 24.00
Invert(ft): 27.000
Manning's N: 0.013000
Top Clip(in): 0.000
Bot Clip(in): 0.000
From Node: Pond 2
To Node: BNDY1
DOWNSTREAM
Circular
24.00
24.00
26.800
0.013000
0.000
0.000
Upstream FHWA Inlet Edge Description:
Circular Concrete: Square edge w/ headwall
Downstream FHWA Inlet Edge Description:
Circular Concrete: Square edge w/ headwall
*** Weir 1 of 2 for Drop Structure Pond2 - BNDY1 **+
L
Length(ft): 88.00
Count: 1
Friction Equation: Average Conveyance
Solution Algorithm: Automatic
Flow: Both
Entrance Loss Coef: 0.000
Exit Loss Coef: 0.000
Outlet Ctrl Spec: Use do or tw
Inlet Ctrl Spec: Use do
Solution Inca: 10
TABLE
Interconnected Channel and Pond Routing Model (ICPR) ©2002 Streamline Technologies, Inc.
Page 3 of 6
L

Olsen Park
- Phase 1
Post Development
2/19/2009
++++++*+++++++++*+++ INPUT REPORT +++++++++++++++++++++*
Count:
1
Bottom Clip(in):
�v
0.000
Type:
Vertical: Mavis
Top Clip(in):
0.000
Flow:
Both
Weir Disc Coef:
3.200
Geometry:
Rectangular
Orifice Disc Coef:
0.600
Span(in):
6.00
Invert(ft):
27.000
Rise(in):
6.00
Control Elev(ft):
27.000
j*** Weir 2
of 2 for Drop
Structure Pond2
- BNDY1 ***
TABLE
Count:
1
Bottom Clip(in):
0.000
Type:
Horizontal
Top Clip(in):
0.000
Flow:
Both
Weir Disc Coef:
3.200
Geometry:
Rectangular
Orifice Disc Coef:
0.600
Span(in):
36.00
Invert(ft):
30.600
f______________________________________________________________________________________
Rise(in):
36.00
Control Elev(£t):
30.600
Weirs=------------------------------------------------------------------
i
Name: Wier From Node: Pond 2
Group: BASE To Node: BNDY1
` Flow: Both Count: 1
Type: Vertical: Mavis Geometry: Rectangular
Span(in): 60.00
Rise(in): 12.00
Invert(ft): 30.800
Control Elevation(ft): 30.800
TABLE
Bottom Clip(in): 0.000
Top Clip(in): 0.000
Weir Discharge Coef: 3.200
Orifice Discharge Coef: 0.600
E
r
Hydrology Simulations
------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------
l
I
Name: post002-YR
Filename: N:\20050\Dsgn\ICPR Model\post002-YR.R32
Override Defaults: Yes
Storm Duration(hrs): 24.00
Rainfall File: Scsiii
Rainfall Amount(in): 4.67
Time(hrs) Print Inc(min)
--------------- ---------------
10.000 15.00
15.000 10.00
24.000 15.00
----------------------------------------------------------------------------------------------------
Name: post010-YR
Filename: N:\20050\Dsgn\ICPR Model\post010-YR.R32
Override Defaults: Yes
Storm Duration(hrs): 24.00
Rainfall File: Scsiii
Rainfall Amount(in): 7.25
Time(hrs) Print Inc(min)
--------------- ---------------
10.000 15.00
15.000 10.00
24.000 15.00
---------------------------------------------------------------------------
Name: post025-YR
Filename: N:\20050\Dsgn\ICPR Mode1\post025-YR.R32
Override Defaults: Yes
Storm Duration(hrs): 24.00
Rainfall File: Scsiii
Rainfall Amount(in): 9.11
L
Interconnected Channel and Pond Routing Model (ICPR) 02002 Streamline Technologies, Inc. Page 4 of 6

Olsen Park - Phase 1
Post Development
i 2/19/2009
*****************+*+ INPUT REPORT ++*++++++++++++++++++*
• Time(hrs) Print Inc(min)
il{ -----
10.000 15.00
15.000 10.00
`` 24.000 15.00
Name: post100-YR
Filename: N:\20050\Dsgn\ICPR Model\post100-YR.R32
Override Defaults: Yes
Storm ➢uration(hrs): 24.00
Rainfall File: Scsiii
Rainfall Amount(in): 12.65
Time(hra) Print Inc(min)
------------------------------
10.000 15.00
15.000 10.00
24.000 15.00
------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------
___= Routing Simulations
Name: pcst002-YR Hydrology Sim: post002-YR
Filename: N:\20050\Dsgn\ICPR Model\post002-YR.I32
I Execute: Yes Restart: No Patch: No
Alternative: No
Max Delta Z(ft): 1.00 Delta Z Factor: 0.00500
Time Step Optimizer: 10.000
Start Time(hrs): 0.000 End Time(hrs): 24.00
Min Calc Time(sec): 0.5000 Max Calc Time ( sec ): 60.0000
` Boundary Stages: Boundary Flows:
Time(hrs) Print Inc(min)
------------------------------
10.000 15.000
15.000 10.000
24.000 15.000
Group Run
--------------- -----
BASE Yes
---------------- --- - -- - - '-" --' --_ _.. --'---'--" ---------'- ---- - -" - -----`-------
Name: post010-YR Hydrology Sim: post010-YR
Filename: N:\20050\Dsgn\ICPR Model\post010-YR.I32
Execute: Yes Restart: No Patch: No
Alternative: No
Max Delta Z(ft): 1.00 Delta Z Factor: 0.00500
Time Step Optimizer: 10.000
Start Time(hrs): 0.000 End Time(hrs): 24.00
Min Calc Time(sec): 0.5000 Max Calc Time(sec): 60.0000
Boundary Stages: Boundary Flows:
Time(hrs) Print Inc(min)
------------------------------
10.000 15.000
15.000 10.000
24.000 15.000
Group Run
--------------- -----
BASE Yes
i
Name: post025-YR Hydrology Sim: post025-YR
Filename: N:\20050\Dsgn\ICPR Model\post025-YR.I32
Execute: Yes Restart: No Patch: No
Alternative: No
Interconnected Channel and Pond Routing Model (ICPR) 02002 Streamline Technologies, Inc. Page 5 of 6

Olsen Park - Phase 1
r Post Development
1 2/19/2CO9
*****+x*******++**** INPUT REPORT *+ax++++++x+++++++*+*+
Max Delta Z(ft): 1.00
Time Step Optimizer: 10.000
Start Time(hrs): 0.000
Min Calc Time(sec): 0.5000
Boundary Stages:
Time(hrs)
Print Inc(min)
---------------
10.000
---------------
15.000
15.000
10.000
24.000
15.000
Group Run
--------------- -----
BASE Yes
Delta Z Factor: 0.00500
End Time(hrs): 24.00
Max Calc Time(sec): 60.0000
Boundary Flows:
----------------------------------------------------------------------------------------------------
Name: post100-YR Hydrology Sim: post100-YR
Filename: N:\20050\Dsgn\ICPR Model\post100-YR.I32
Execute: Yes Restart: No Patch: No
Alternative: No
Max Delta Z(ft): 1.00 Delta Z Factor: 0.00500
Time Step Optimizer: 10.000
Start Time(hrs): 0.000 End Time(hrs): 24.00
Min Calc Time(sec): 0.5000 Max Calc Time(sec): 60.0000
Boundary Stages: Boundary Flows:
Time(hrs) Print Inc(min)
------------------------------
10.000 15.000
15.000 10.000
24.000 15.000
Group Run
--------------- -----
BASE Yes
Interconnected Channel and Pond Routing Model (ICPR) ©2002 Streamline Technologies, Inc.
Page 6 of 6

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rt a

Olsen Park - Phase 1
Now Hanover County, North Carolina
Section 2.4
Combined Unit Hydrograph Calculations
Prepared By
Thomas & Hutton Engineering Co.
219 Station Rd. / Wilmington / NC / 28405
50 Park of Commerce Way / Savannah / GA / 31405
935 Houston Northcutt Blvd. / Mt. Pleasant / SC / 29464
1350 Farrow Pkwy / Myrtle Beach / SC / 29577
116 West Palm Plaza Drive / Brunswick / GA / 31523
J-20050

Olsen Park - Phase 1
Post - Development Runnoff Rates
Thomas and Hutton Engineering Co.
2-YEAR STORM 10-YEAR STORM 25-YEAR STORM 100-YEAR STORM
Time
BNDY 1
BNDY 2
COMPOSITE
Outflow
Outflow
Outflow
hrs
cfs
cfs
cfs
0.00
0.00
0.00
0.00
0.26
O.DO
0.00
0.00
0.50
0.00
0.00
0.00
0.77
O.00
0.00
0.00
1.02
0.00
0.00
0.00
1.27
0.00
0.00
0.00
1.52
0.00
0.00
0.00
1.77
0.00
0.00
0.0
2.02
0.00
0.00
0.0
2.27
0.00
0.00
0.0
2.52
0.00
0.00
0.0
2.77
0. 00
0.00
0.00
3.02
0.00
0.00
0.00
3.271
0.001
0.00
0.00
3.52
0.00
0.00
0.00
3.77
0.00
0.00
0.06
4.02
0.00
0.00
0.0
4.27
0.00
0.00
0.00
4.62
0.00
0.00
0.00
477
0.00
0.00
0.00
5.02
0.00
0.00
0.00
5.27
0.00
0.00
0.00
5.521
0.001
0.00
0.00
5.77
0.00
0.00
0.
6.02
0.00
0.00
o.DO
6.27
0.00
0.00JOY,
0
6.52
0.00
0.000
6.77
0.00
0.000
7.02
0.00
0.00
7.27
0.00
0.00
7.50
0.01
0.001
7.75
0.02
0.00
8.00
0.04
0.00
8.25
0.05
0.005
8.51
0.07
O.DO
8.76
0.09
O.DO9
9.01
0.11
0.001
9.26
0.14
0.00
9.51
0.19
0.01
9.76
0.27
0.04110.01
0.36
0.10.6
10.26
0.48
0.18
0.66
10.43
0.69
0.24
0.83
10.80
0.72
0.31
1.03
10.76
0.90
0.40
1.30
10.92
1.15
0.52
1.6
11.09
1.42
0.65
2.08
11.25
1.73
0.80
2.5E
11.42
2.18
1.02
3.20
11.58
2.87
1.36
4.22
11.78
4.30
2.02
6.3
11.92
8.88
4.28
13.1
12.09
19.13
9.37
28.5
12.25
30.46
14.75
45.21
12.42
34.38
16.08
50.4
12.58
28.85
12.62
41.4
12.75
21.31
8.44
29.76
12.921
16.371
5.94
22.31
13.08
13.27
4.51
17.78
13.25
11.23
3.67
14.90
13.42
9.88
3.16
13.0
13.59
8.80
2.78
11.58
13.75
8.08
2.65
10.62
13.92
7.52
2.38
9.90
14.08
7.04
2.21
9.26
14.26
6.60
2.05
8.65
14.431
6.281
1.95
8.23
14.60
6.07
1.88
7.95
14.76
5.81
1.78
7.69
14.93
5.54
1.67
7.21
15.10
5.38
1.61
6.98
15.35
5.17
1.54
6.71
15.60
4.92
1.43
6.35
15.85
4.73
1.36
6.1
16.10
4.63
1.33
5.9
16.35
4.47
1.28
5.73
16.60
4.33
1.21
5.5
16.85
4.17
1.14
5.31
17.10
3.84
0.98
4.82
17.35
3.481
0.83
4.31
17.60
3.341
0.78
4.12
Time
BNDY 1
BNDY 2
COMPOSITE
Outflow
Outflow
Outflow
hrs
cfs
cfs
cfs
0.00
0.00
0.00
0.0
0.26
0.00
0.00
0.0
0.50
0.00
0.00
D.00
0.77
0.00
0.00
0.00
1.02
0.00
0.00
0.00
1.27
0.00
0.00
0.00
1.52
0.00
0.00
0.00
1.77
O.00
0.00
0.00
2.02
0.00
0.00
0.00
2.27
0.00
0.00
0.00
2.52
0.00
0.00
0.00
2.77
0.00
0.00
0.00
3.02
0.00
0.00
0.00
3.271
0.001
0.00
0.
3.52
0.00
0.00
0.00
3.77
0.00
0.00
0.00
4.02
0.00
O.Oo
0.00
4.27
0.00
0.00
0.00
4.52
0.00
0.00
0.0
4.77
0.00
0.00
0.0
5.02
0.00
0.00
0.0
5.27
0.00
0.00
0.0
5.521
0.011
0.00
0.01
5,77
0.02
0.00
0.0
6.02
0.031
0.06
0.0
6.27
0.04
0.00
0.0
6.52
D.05
0.00
0.05
6.77
0.06
0.00
0.06
7.02
0.08
0.00
0.08
7.27
0.09
0.00
0.09
7.50
0.12
0.00
0.12
7.75
0.18
0.00
0.18
8.00
0.29
0.04
0.33
8.251
0.381
0.10
0.48
8.51
0.48
0.17
0.65
8.76
0.63
0.27
0.90
9.01
O.B4
0.37
1.2
9.26
1.08
6.49
1.5
9.51
1.30
0.59
1.89
9.76
1.62
0.74
2.36
10.01
1.96
0.B9
2.8
10.26
2.36
1.07
3.4
10.43
2.76
1.26
4.01
10.60
3.13
1.42
4.5
10.76
3.67
1.65
5.3
10.92
4.33
1.94
6.2
11.09
5.13
2.28
7.41
11.25
6.92
2.59
8.51
11.42
7.09
3.09
10.18
11.58
8.85
3.90
12.75
11.76
12.11
5.39
17.49
11.92
22.50
10.49
32.99
12.091
43.671
21.03
64.70
12.25
65.47
31.39
96.86
12.42
70.42
32.90
10S.32
12.58
57.46
25.19
82.65
12.75
41.69
18.55
58.23
12.92
31.76
11.44
QUO
13.08
25.70
8.55
34.24
13.25
21.90
6.91
28.80
13.42
19.24
5.87
25.10
13.59
17.23
5.16
22.3
13.75
15.81
4.70
20.51
13.92
14.68
4.39
19.0
14.08
13.50
4.06
17.56
14.26
12.47
3.77
16.24
14.43
11.68
3.57
16.2
14.60
11.08
3.44
14.5
14.76
10.50
3.26
13.7
14.93
9.90
3.05
12.9
15.10
9.49
2.93
12.41
15.35
9.031
2.79
11.81
15.60
8.52
2.59
11.11
15.85
8.16
2.46
10.62
16.10
7.94
2.39
10.34
16.35
7.65
2.27
9.92
16.60
7.39
2.17
9.56
16.85
7.09
2.05
9.14
17.10
6.48
1.78
8.25
17.35
5.85
1.491
7.311
17.60
5-581
1.401
6.98
Time
BNDY 1
BNDY 2
COMPOSITE
Outflow
Outflow
Outflow
hrs
cis
cis
cfs
0.00
0.00
0.00
0.00
0.26
0.00
0.00
0.00
0.50
0.00
0.00
0.00
D.77
0.00
0.00
0.06
1.02
0.00
0.00
0.00
1.27
0.00
0.00
0.00
1.52
0.00
0.00
0.00
1.77
0.00
0.00
0.0
2.02
0.00
0.00
0.00
2.27
0.00
0.00
0.0
2.52
0.00
0.00
0.0
2.77
0.00
0.60
0.0
3.D2
0.00
0.00
0.00
3.27
0.001
0.00
0.00
3.52
0.00
0.00
0.00
3.77
0.00
0.00
0.00
4.02
0.00
0.00
0.00
4.27
0.00
0.00
0.00
4.52
0.01
0.00
0.01
4.77
0.01
0.00
0.01
5.02
0.03
0.00
0.03
5.27
0.04
0.00
0.04
5.521
0.051
0.05
-0.05
5.77
0.071
0.00
0.0
6.02
0.091
0.00
0.09
6.27
0.11
0.00
0,11
6.52
0.12
0.001
0.12
6.77
0.17
0.00
0.17
7.02
0.22
0.02
0.24
7.27
0.27
0.06
0.33
7.50
0.38
0.12
0.5
7.75
0.54
0.21
0.7
8.00
0.80
0.35
1.1
825
1.01
0.45
1.45
8.61
1.201
0.65
1.75
8.70
1.55
0.71
2.26
9.01
1.90
0.87
2.7
9.26
2.29
1.04
3.33
9.51
2.52
1.19
3.81
9.76
3.14
1.41
4.55
10.01
3.72
1.64
5.36
10.26
4.39
1.90
6.29
10.43
5.06
2.17
7.23
10.60
5.66
2.41
8.07
10.76
6.47
2.75
9.22
10.92
7.46
3.18
10.63
11.09
8.57
3.67
12.24
11.25
9.64
4.12
13.76
11.42
11.22
4.81
16.03
11.58
13.77
6.00
19.78
11.76
18.32
8.08
26.41
11.92
33.43
15.51
48.94
12.091
62.861
30.22
93.08
12.25
91.52
44.08
135.
12.42
97.18
45.55
142.
12.58
78.01
34.47
112.
12.75
61.85
22.61
64.3
12.92
51.09
15.44
66.5
13.08
42.71
11.49
54.20
13.25
36.70
9.28
45.9
13.42
32.13
7.871
40.00
13.59
28.461
6.88
35.3
13.75
25.731
6.28
32.01
13.92
23.49
5.84
29.32
14.08
21.49
5.41
26.91
14.26
19.63
5.01
24.64
14.43
18.32
4.75
23.06
14.60
17.20
4.57
21.76
14.76
16.01
4.33
20.34
14.93
14.80
4.05
18.84
15.10
13.90
3.88
17.78
15.35
12.89
3.70
16.59
15.60
11.87
3.43
15.31
15.85
11.11
3.25
14.3
1B.10
10.64
3.16
13.81
16.35
1D.10
3.00
13.1
16.60
9.62
2.86
12.4
16.85
9.13
2.70
11.83
17.10
8.20
2.33
10.53
17.35
7.21
1.96
9.17
17.60
6.78
1.85
8.63
Time
IBNDY1
1BNDY2
COMPOSITE
Outflow
loutflow
Outflow
hrs
cfs
cfs
cfs
0.00
0.00
0.00
0.00
0.26
0.00
0.00
0.00
0.50
0.00
0.00
0.0
0.77
0.OD
0.00
0.00
1.02
0.00
0.00
0.00
1.27
0.00
0.00
0.00
1.52
0.00
0.00
0.00
1.77
0.00
0.00
0.
2.02
0.00
0.00
0.
2.27
0.00
0.00
0.
2.62
0.00
0.00
0.0
2.77
0.00
0.00
0.0
3.02
0.00
0.06
0.00
3.27
0.00
0.00
0,00
3.52
0.01
0.001
0.01
3.77
0.02
0.00
0.02
4.02
0.04
D.00
0.0
4.27
0.071
0.00
0.0
4.52
0.09
0.00
0.0
4.77
0.10
0.00
0.10
5,02
0.14
0.00
0.1
5.27
0.17
0.00
0.1
5.52
0.22
0.02
0.2
5.77
0.32
0.071
0.3
6.02
0.40
0.13
0.52
6.27
0.51)
0.20
0.7
6.521
0.59
0.25
0.8
6.771
0.76
0.33
1.09
7.02
0.93
0.42
1.34
7.27
1.07
0.48
1.54
7.50
1.41
0.64
2.
7.75
1.861
0.85
2.71
8.00
8.25
2.49
1.15
3.8
2.92
1.33
4.2
8.51
3.29
1.46
4.75
8.76
4.00
1.76
5.76
9.01
4.70
2.03
6.72
9.26
5,48
2.32
7.79
9.51
6.10
2.54
8.63
9.76
6.99
2.90
9.891
10.011
7.871
3.26
11.13
10.26
8.95
3.71
12 .66
10.43
9.981
4.16
14.1
10.60
10.89
4.54
15.43
10.76
12.13
5.08
17.21
10.92
13.82
5.83
19.66
11.09
15.51
6.57
22.08
11.25
17.28
7.32
24.60
11.42
19.69
8.38
28.0
11.58
23.61
10.22
33.83
11.76
30.97
13.61
44.56
11.921
54.521
25.26
79.781
12.09
W331
47.98
147.31
12.25
142.07
68.76
210.8
12.42
170.61
69.93
240.54
12.58
148,96
52.46
201.4
12.75
110.65
33.86
_
Y14451
12.92
84.67
23.14
107.8
13.08
67.98
17.13
85.10
13.25
57.07
13.76
70.8
13.421
49.241
11.64
60.88
13.591
43.381
10.18
53.56
13.751
39.131
9.25
48.38
13.92
35.931
8.59
44.52
14.08
33.241
7.95
41.19
14.26
30.84
7.36
38.21
14.43
28.93
6.97
35.89
14.60
27.36
6.70
34.08
14.76
26.67
6.34
32.D1
14.93
23.83
5.92
29.75
15.10
22.38
5.68
28.06
15.35
20.54
5.41
25.98
15.60
18.68
5.03
23.71
15.85
17.341
4.75
22.0
16.10
16.27
4.63
20.9
16.35
15.15
4.38
19.5
16.60
14.23
4.18
18.41
16.85
13.37
3.94
17.31
17.10
11.91
3.39
15.31
17.35
10.33
2.121
13.18
17.60
9.53
2.89
12.22
Page 1 of 2

Olsen Park - Phase 1
Post - Development Runnoff Rates
Thomas and Hutton Engineering Co.
2-YEAR STORM 10-YEAR STORM 25-YEAR STORM 100-YEAR STORM
Time
BNDY1
BNDY2
COMPOSITE
Outflow
Outflow
Outflow
hrs
cfs
cis
cfe
17.85
3.21
0.77
4.0
18.10
3.21
0.76
3.9
18.35
3.07
0.70
3.77
18.60
2.91
0.63
3.5
18.55
2.86
0.63
3.49
19.10
2.98
0.65
3.53
19.35
2.80
0.62
3.42
19.60
2.76
0.61
3.36
19.85
2.71
0.59
3.30
20.10
2.62
0.56
3.17
20.35
2.55
0.53
3.08
20.60
2.51
0.52
703
20.851
2.491
0.52
3.01
21.10
2.48
0.53
3.01
21.35
2.48
0.54
3.02
21.60
2.45
0.53
2.9
21.85
2.43
0.53
2.9
22.10
2.38
0.61
2.8
22.35
2.27
0.46
2.7
22.60
2.21
0.44
2.66
22.85
2.20
0.45
2.65
23.101
2.181
0.45
2.6311
23.35
2.16
0.44
2.60
23.80
2.13
0.44
2.5ZI
23.851
2.081
0.421
2.50
24.001
1.991
0.381
2371
Time
BNDY1
BNDY2
COMPOSITE
Outflow
Outflow
Outflow
hrs
cfs
cfs
cfs
17.85
5.45
1.38
6.83
18.10
5.36
1.36
6.71
18.35
5.12
1.26
6.38
18.60
4.83
1.13
5.96
18.85
4.76
1.12
5.89
19.10
4.80
1.16
5.9
19.35
4.68
1.10
5.78
19.60
4.61
1.D8
5.6
19.85
- 4.54
1.06
5.59
20.10
4.37
0.99
5.36
20.35
4.26
0.94
5.20
20.60
4.20
0.93
5.13
20.85
4.17
0.93
5.10
21.101
4.171
0.94
5.11
21.35
4.19
0.95
5.1
21.60
4.15
D.94
5.08
21.85
4.12
0.93
5.05
22.10
4.04
0.89
4.93
22.35
3.86
0.81
4.8
22.60
3.77
0.78
4.55
22.85
3.75
0.79
4.5
23.10
3.74
0.79
4.531
23.35
3.71
0.79
4.
23.61)
3.68
0.78
4.4
23.85
3.59
0.74
4
24.00
3.44
0.67
4.1.3
1
Time
BNDY1
IBNDY2
COMPOSITE
Outflow
loutlow
Outflow
hrs
cfs
cis
17.85
6.61
1.82
18.10
6.48
1.79
18.35
6.18
1.65
17..057
18.60
5.80
1.49
18.85
5.70
1.48
19.10
5.76
1.53
19.35
6.60
1.45
19.60
5.511
1.42
6.93
19.85
5.421
1.39
6.81
20.10
5.22
1.30
6.51
20.35
5.07
1.24
6.31
20.60
4.99
1.22
6.21
20.85
4.96
TO
6.18
21.10
4.96
1.23
6.19
21.35
4.99
1.25
6.24
21.60
4.94
1.23
6.1
21. 55
4.91
1.22
6.13
22.10
4.81
1.17
5.9
22.35
4.58
1.07
5.65
22.60
4.46
1.03
5.49
22.85
4.46
1.04
5.48
23.10
4.43
1.04
5.4
23.35
4.39
1.03
5.
23.60
4.35
1.02
5.3
23.85
4.26
0.97
5.2
24.00
4.06
0.88
4.9
Time
BNDY!
BNDY2
COMPOSITE
outflow
outflow
outflow
hrs
cfs
ds
cfs
17.85
9.10
2.64
11.7
18.10
8.80
2.60
11.39
18.35
8.26
2.41
10.66
18.60
7.61
2.16
9.77
18.85
7.43
2.14
9.58
19.10
7.52
2.22
9.74
19.35
7.30
2.11
9.41
19.60
7.17
2.07
9.2
19.85
7.05
2.02
9.0
20.10
6.75
1.88
8.63
20.35
6.54
1.80
8.3
20.60
6.44
1.77
8.21
20.85
6.40
1.77
8.17
21.101
6.411
1.78
8.19
21.351
6.451
1.81
8.26
21.601
6.391
1.78
8.1
21.85
6.36
1.77
8.13
22.10
6.21
1.70
7.91
22.35
5.88
1.55
7.43
22.60
5.72
1.49
7.20
22.85
5.70
1.60
7.20
23.10
5.69
1.51
7.19
23.35
5.64
1.491
7.13
23.60
5.59
1.47
7.
23.85
5.46
1.41
6.87
24.00
5.17
1.27
8.
Page 2 of 2

TOTAL FLOW (cfs)
0-]
Cn
O
N
O
�A � *A �
O O O O O O O O O
�O
O
O
b
o
N r v�i
,ia
W

TOTAL. FLOW (efs)
H,
W
O
N�
0
W
O
-i
I
�o
d�
c°
b
00
�
0 �
z z �
1\3
6
A�

r

a
ti
TO BURGAW
\(
oNtp
13
O tj
>
0
0 �y
U T w
INTERSTATE 40 (R/W VARIES)
CURVE TABLE
CURVE
LENGTH
RADIUS
DELTA
TANGENT
CHORD
CHORD
Cl
1 911.09
2704.79
19017'59"
459.90
1 N21007'48"W j
906.79
PERMIT AREA LINE TABLE
S32°33'38"E o39'13"E S34°31'58"E S34°45'50"E _ S34038'58"E S34008'58"E S33008'580E S31°38'56"E LINE LENGTH BEARING
•-F -- — . .. . ` S4! ..■ 201.15' ` ` 825.47' �7 \ 99.19'--97.9i' 96.52 ! �• g5,45' ° "
LI 48,83 N4605824"W
513.32, "` "" '` 111.85 / �``"`� L2 49.37 N45 02 26 W
L3 9.00 N01048'32"E
--=------------50 BUFFER---- �L-------------------_... /� � .. 50'46"E
--- — — -- —-------------------/ —-------------------- ��— - 37_r____-- -- , L4 19.61 N71°
— — L5 44.44
— ��— — _ — — _ f 6—i N20°45'21"E
NOO 42 03 W
\ \ /
\ 1 \ \ ) \ / \ /. �- \ 3.\ \ _ ♦ N32058'038E
/ L7 16.49
\ / ,/
\ \ l f 3B .t \ - /
w \ �— /
\ f ,7 / >
PROPOSED / = \ •!
•r /
BALLFIELD #5
%f \
� , a
10' ASPHALT PATH
5
39
�\ �'O •� \ \ \ \ \ / \ `/ \ PROPOSED J
0 935�BALLFIELD #I �
z SOUTHSIDE HOLDINGS. LLC ��►� �� \� � \ \~ \ / _ -/ \ \ '\ ° ( `J
R02620-003-005-000 \
D.B. 5031 PG. 1586 �ti\ � � �' �• �� � � �- 1 � a \:.^, - --- 00
4 f } EXISTING
WOODLINE
WOODED
\°oo
FUTURE I" FUTURE MIRACLE FIELD ;=<,.Y.. ; j '�
PF�ASC / :... PROPOSED RESTROOM/
(IMPERVIOUS) \ CONCESSION BUILDING
EXISTING
WOODLINE
SCORING BOOTH PAD , .. ::. -.,:-> •- , . ,...... .. \ - % �'" <.:::•. s � ,. .:. e: � �
\' 3 (TYPICAL EACH FIELD) _:
n
:.
i PROPOSED RESTROOM " r / rr
'>"•=' ' r � . � FUTURE
VENDING BUILDING l ; ,
% s --
J PLAYGROUND AREA
So •S / .-- \ . »� x3 (IMPERVIOUS) . fr _,- =-`� -
) Y 7
/ \ I
34 Z
J � \
Cv
/r
2
r &
EXISTING i �o
/ STREAM 2
MAINTENANCE,'
BUILDING 81 PARKING
/ tir
LUDLUM, GLENN
ET AL � \ PERMIT AREA j / �-
r` R02620-005-031-000
STREAM i
- v . r••rr•. r r v ••r - -
2 PRESERVATION AREA
28 — 2z
50'STREAM o
;
— BUFFER
AM
29.
fA
� \ FUTURE 0°o
PHASE �
WOODED \ /
EXISTING
wx WOODLINE l `4✓
0
D.B. 5205 PG. 947
r, \ ` R�SM l l j f J. I PERMIT AREA
^ 2-`-----'� \\ / \ �' \ \G�'t� % � / �� 4t
co
lQF
tj
/ 40
— I I fu
v I f 3�� �i, t / / / / I I JJI�
W N I J �JJJ EXISTING
< / / WOODED I 1 WETLAND / RESOURCE U. I I ( I STREAM 3
LEGAL /DESCRIPTION
r ,\ PRESERVATION AREA I 111
m Ili
404 WETLAND
CONSERVATION OVERLAY
DISTRICT (COD)
COD SETBACK
RESOURCE PRESERVATION
AREA FOR MITIGATION
TEMPORARY GRAVEL
TURNAROUND
PARKING / ROAD
` SIDEWALK
s-
PHASEIBOUNDARY
. • . • — • -- • — DRAINAGE PIPE
---► - - - DRAINAGE SWALE
WOODLINE
PROPOSED BUILT UPON AREA (PHAS
BUILDINGS:
PICNIC SHELTER: 1,800 SF
RESTROOM/CONCESSION: 19890 SF
RESTROOM/VENDING: 915 SF
MAINTENANCE BUILDING: 4,200 SF
(5) SCORING BOOTHS: 400 SF
TOTAL BUILDINGS: 9,205
STREETS: 51,526 SF
PARKING: 92,212 SF:
EMERGENGY GRAVEL ACCESS: 24,115 SF
SIDEWALKS AND PATHS: 34,855 SF
FUTURE BUA:
PLAYGROUND: 24,731 SF
MIRACLE FIELDi. 25,587 SF
TOTAL FUTURE BUA: 50,318 SF
TOTAL BUA: 262,231 SF
/ EXISTING
WOODLINE / o _ I
0)
OVERALL .PERMIT REA SUMMARY �IV4�°40- . q'
PERMIT AREA: 3,893,129 SF 3�06 ��
WETLANDS: 176,766 SF �..
COASTAL WETLANDS: 0 SF
UPLAND: 3,716,363 SF / / / / \ / 1 (// •
*PERMIT AREA FOR DENSITY: 3,893,129 SF PERMIT AREA
EXISTING IMPERVIOUS: 0 SF
PROPOSED PERCENT IMPERVIOUS: 6.7% �''��r
* PERMIT AREA = OVERALL PARCEL — COASTAL WETLANDS�'�0�'1/
GRAPHIC SCALE
1100,
100 0 50 t00 zoo
OSwS,�
F \&aZ3��
( IN FEET }
�60 1 inch = 100 ft.
J
NEW HANOVER COUNTY
BOARD OF EDUCATION
R03400-002-003-000
D.B. 1030 PG. 0616
t
TO MURRAYVILLE ROAD
I
OVERALL SITE PLAN
FOR
OLSEN PARK PHASE 1
NEW HANOVER COUNTY NORTH CAROLINA
PREPARED FOR
THE CITY OF WILMINGTON
320 CHESTNUT STREET
P.O. BOX 1810
"°° WILMINGTON, NORTH CAROLINA 28402-1810
[phone]
FEBRUARY 20, 2009

r
r
r

r
CAM
J-20050.404
STORMW ATER
` STORM WATER DESIGN CONSIDERATIONS
( Olsen Park - Phase 1
PREPARED BY: T hornas & Hutton Engineering Co.
DATE: June 16, 2008
REVISED:
STREAM CROSSING DRAINAGE CALCULATIONS
Stream Crossing #1
Determine Composite CN Value from TR-55 Table 2-2
Description
HSG
CN
A (ac)
CN x A
Impervious
B
89
12.00
1068.00
Impervious
D
98
3.25
318.50
Open Space (Fair)
B
69
20.50
1414.50
Open Space (Fair)
C
79
5.00
395.00
Open Space (Fair)
D
84
8.00
672.00
Woods (Fair)
B
60
46.75
2805.00
Woods (Fair)
C
79
3.00
237.00
Woods (Fair)
D
84
28.00
2352.00
126.50
9262.00
Composite CN Value = 73
Calculate Time of Concentration
Use Travel Time Concept:
Overland Flow: t =(0.007(nl)A0.8)/((P2A0.5)"(SAO.4)) TR-55 Eq 3-3
where: t = Travel time for Overland How (min)
n = Manning's coefficient - from TR-55 Table 3-1
1= Length of flow (ft)
P2 = 2-yr rainfall depth (in)
S = Hydraulic slope (ft/ft)
IRange/natural
n = 0.24 grass (dense)
I = 100 ft
j
P2 = 4.5 in
I
S = 0.005 ft/ft
t = 21.0 min
Shallow Concentrated Flow: t=1/60v
where: t--Travel time for Shallow Concentrated Flow (min)
1=Length of flow (ft)
S=Average watercourse slope (ft/ft)
v=Velocity (ft/s)- From TR-55
1= 1000.00 ft
S= 0.005 Unpaved
v= 1.14 ft/s
t= 14.61 min
Channel Flow: 1=1/60v
where: t=Travel time for Pipe Flow (min)
1=Length of flow (ft)
v=Velocity (ft/s)- From TR-55
1= 2450.00 ft
f
v= 2.00 ft/s
t= 20.42 min
LTherefore,
Te = 56.0 min
N:1200501DsgnlStonnwater120050 Stream Crossing CN.xis Thomas & Hutton Engineering Co. Page 1 of 2

r-
CAM
-20050.404
STREAM CROSSING DRAINAGE CALCULATIONS
Stream Crossing #2
Determine Composite CN Value from TR-55 Table 2-2
I Description HSO CN A (ac)
CN x A
Impervious B 89 5.00
445.00
Open Space (Fair) B 69 31.00
2139.00
Woods (Fair) B 60 2.00
120.00
Woods (Fair) D 84 0.50
42.00
38.50
2746.00
Composite CN Value = 71
I Calculate Time of Concentration
Use Travel Time Concept:
Overland Flow: t =(0.007(nl)^0.8)/((P2^0.5)*(S^0.4)) TR-55 Eq 3-3
I where: t = Travel time for Overland Flow (min)
n = Manning's coefficient - from TR-55 Table 3-1
1= Length of flow (ft)
P2 = 2-yr rainfall depth (in)
IS = Hydraulic slope (ft/ft)
Range/natural
n = 0.24 grass (dense)
I= 100 ft
P2 = 4.5 in
I)
S = 0.005 ft/ft
t= 21.0 min
I Shallow Concentrated Flow: t=1/60v
where: t=Travel time for Shallow Concentrated Flow (min)
1=Length of flow (ft)
S=Average watercourse slope (ft/ft)
v=Velocity (ft/s)- From TR-55
I
1= 1000.00 ft
S= 0.005 Unpaved
v= 1.14 ft/s
It= 14.61 min
Channel Flow: t=1/60v
where: t=Travel time for Pipe Flow (mitt)
1=Length of Flow (ft)
v=Velocity (ft/s)- From TR-55
1= 550.00 ft
v= 2.00 ft/s
t= 4.58 min
i
,
( Therefore, Te = 40.1 min
N:\20050\Dsgn\Stormwater\20050 Stream Crossing CN.xls Thomas & Hutton Engineering Co. Page 2 of 2

Name: Stream Basin 1
Group: BASE
Unit Hydrograph: Uh484
Rainfall File: Scsiii
f Rainfall Amount(in): 0.000
ti{ Area(ac): 126.500
Curve Number: 73.00
DCIA(%): 0.00
Node: Stream 1 Status: Onsite
Type: SCS Unit Hydrograph CN
Peaking Factor: 484.0
Storm Duration(hrs): 24.00
Time of Conc(min): 56.00
Time Shift(hrs): 0.00
Max Allowable Q(cfs): 999999.000
----------------------------------------------------------------------------------------------------
Name: Stream Basin 2 Node: Stream 2 Status: Onsite
Group: BASE Type: SCS Unit Hydrograph CN
Unit Hydrograph: Uh484
Rainfall File: Scsiii
Rainfall Amount(in): 0.000
Area(ac): 38.500
Curve Number: 71.00
DCIA(%): 0.00
Peaking Factor: 484.0
Storm Duration(hrs): 24.00
Time of Conc(min): 40.10
Time Shift(hrs): 0.00
Max Allowable Q(cfs): 999999.000
-----------------------------------------------
---------------------
Nodes Name; Stream Stream 1 Base Flow(cfs): 0.000 Init Stage(ft): 0.000
Group: BASE Warn Stage(ft): 0.000
Type: Stage/Area
Stage(ft) Area(ac)
------------------------------
------------------------------------------------------------------------------------------
Name: Stream 2 Base Flow(cfs): 0.000 Init Stage(ft): 0.000
Group: BASE Warn Stage(ft): 0.000
Type: Stage/Area
Stage(ft) Area(ac)
------------------------------
--------------------------------------------------
__________________________________________________________________
Hydrology Simulations = ------------
Name: 100-Yr
Filename: N:\20050\Dsgn\ICPR Model\100-Yr.R32
Override Defaults: Yes
Storm Duration(hrs): 24.00
Rainfall File: Scsiii
Rainfall Amount(in): 12.65
i Time(hrs) Print Inc(min)
fI------------------------------
F 10.000 15.00
15.000 10.00
24.000 15.00
------------------------------------------`---------------------------------------------------------
Name: 25-Yr
Filename: N:\20050\Dsgn\ICPR Model\25-Yr.R32
Override Defaults: Yes
Storm Duration(hrs): 24.00
Rainfall File: Scsiii
Rainfall Amount(in): 9.11
Time(hrs) Print Inc(min)
--------------- ---------------
10.000 15.00
15.000 10.00
24.000 15.00
Interconnected Channel and Pond Routing Model (ICPR) 02002 Streamline Technologies, Inc.
Page 1 of I

` Basin Name: Stream Basin 1
Group Name: BASE
Simulation: 100-Yr
Node Name: Stream 1
Basin Type: SCS Unit Hydrograph
Unit Hydrograph: Uh484
Peaking Fator: 484.0
Spec Time Inc (min): 7.47
Comp Time Inc (min): 7.47
Rainfall File: Scsiii
Rainfall Amount (in): 12.650
Storm Duration (hrs): 24.00
Status: Onsite
Time of Conc (min): 56.00
Time Shift (hrs): 0.00
Area (ac): 126.500
Vol of Unit Hyd (in): 1.001
Curve Number: 73.000
DCIA M : 0.000
Time Max (hre): 12.57
Flow Max (cfs): 549.481
Runoff Volume (in): 9.065
Runoff Volume (ft3): 4162752.189
Basin Name: Stream Basin 2
Group Name: BASE
Simulation: 100-Yr
Node Name: Stream 2
Basin Type: SCS Unit Hydrograph
Unit Hydrograph: Uh484
Peaking Fator: 484.0
Spec Time Inc (min): 5.35
Comp Time Inc (min): 5.35
Rainfall File: Scsiii
Rainfall Amount (in): 12.650
Storm Duration Mrs): 24.00
Status: Onsite
Time of Conc (min): 40.10
Time Shift (hrs): 0.00
Area (ac): 38.500
Vol of Unit Hyd (in): 1.000
Curve Number: 71.000
DCIA (8): 0.000
Time Max (hrs): 12.48
Flow Max (cfs): 197.541
Runoff Volume (in): 8.782
Runoff Volume (ft3): 1227339.522
Basin Name: Stream Basin 1
Group Name: BASE
Simulation: 25-Yr
Node Name: Stream 1
Basin Type: SCS Unit Hydrograph
Unit Hydrograph: Uh484
Peaking Fator: 484.0
Spec Time Inc (min): 7.47
Comp Time Inc (min): 7.47
Rainfall File: Scsiii
Rainfall Amount (in): 9.110
Storm Duration (hrs): 24.00
Status: Onsite
Time of Conc (min): 56.00
Time Shift (hrs): 0.00
Area (ac): 126.500
Vol of Unit Hyd (in): 1.001
Curve Number: 73.000
DCIA M : 0.000
Time Max (hrs): 12.57
Flow Max (cfs): 353.425
Runoff Volume (in): 5.790
Runoff Volume (ft3): 2658758.942
Interconnected Channel and Pond Routing Model (ICPR) 02002 Streamline Technologies, Inc. Page 1 of 2
L

Basin Name: Stream Basin 2
Group Name: BASE
Simulation: 25-Yr
I Node Name: Stream 2
Basin Type: SCS Unit Hydrograph
Unit Hydrograph: Uh484
Peaking Fator: 484.0
Spec Time Inc (min): 5.35
Comp Time Inc (min): 5.35
Rainfall File: Scsiii
Rainfall Amount (in): 9.1i0
Storm Duration (hrs): 24.00
Status: Onsite
Time of Conc (min): 40.10
Time Shift (hrs): 0.00
Area (ac): 38.500
Vol of Unit Hyd (in): 1.000
Curve Number: 71.000
DCIA M : 0.000
Time Max (hrs): 12.48
Flow Max (cfs): 126.148
Runoff Volume (in): 5.547
Runoff Volume (ft3): 775228.725
r
Interconnected Channel and Pond Routing Model (ICPR) 02002 Streamline Technologies, Inc. i+ Page 2 of 2

R
L

L
L
L
Culvert Report
Hydraflow Express by Intelisolve
Cir Culvert
Invert Elev Dn (ft)
= 20.24
Pipe Length (ft)
= 84.00
Slope (%)
= 0.90
Invert Elev Up (ft)
= 21.00
Rise (in)
= 48.0
Shape
= Cir
Span (in)
= 48.0
No. Barrels
= 1
n-Value
= 0.013
Inlet Edge
= Sq Edge
Coeff. K,M,c,Y,k
= 0.0098, 2, 0.0398, 0.67, 0.5
Embankment
Top Elevation (ft)
= 33.00
Top Width (ft)
= 45.00
Crest Width (ft)
= 24.00
Thursday, Nov 13 2008, 10:07 AM
Calculations
Qmin (cfs)
= 125.00
Qmax (cfs)
= 200.00
Tailwater Elev (ft)
= (dc+D)/2
Highlighted
Qtotal (cfs)
= 125.00
Qpipe (cfs)
= 125.00
Qovertop (cfs)
= 0.00
Veloc Dn (ft/s)
= 10.33
Veloc Up (ft/s)
= 11.09
HGL Dn (ft)
= 23.92
HGL Up (ft)
= 24.36
Hw Elev (ft)
= 27.60
Hw/D (ft)
= 1.65
Flow Regime
= Inlet Control
Elev (ftj cNamw� Hw Depth (ft)
34.00
__
_ ....
..
13.00
32.00
11.00
30.00
__.._..
9.00
20.00
.. .. _ .. . ....
7.00
_
untrel
Inlet c
26.00
5.00
24.00
,
.. :..
3.00
t
22.00
1.00
20.00
_ . ..
1.00
18.00
•3.00
0 10 20 30 40 50 60 70 80 90 100 110 120 130
Cir Culvert HGL Embank
Reach (ft]

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44

Culvert Report
Hydraflow Express by Intelisolve
Box Culvert
Invert Eiev Dn (ft)
= i 9. i 0
Pipe Length (ft)
= 62.00
Slope (%)
= 0.40
Invert Elev Up (ft)
= 19.35
Rise (in)
= 60.0
Shape
= Box
Span (in)
= 96.0
No. Barrels
= 1
n-Value
= 0.015
Inlet Edge
= Sq Edge
Coeff. K,M,c,Y,k
= 0.061, 0.75, 0.04, 0.8, 0.5
Embankment
Top Elevation (ft)
= 28.50
Top Width (ft) =
45.00
Crest Width (ft) =
24.00
I Elev (ft)
29.00
27.00
25.00
23.00
21.00
I1"00
17.00
r V
<Namw,
Thursday, Nov 13 2008, 10:14 AM
Calculations
Qmin (cfs)
= 350.00
Qmax (cfs)
= 550.00
Tailwater Elev (ft)
= (dc+D)/2
Highlighted
Qtotal (cfs)
= 350.00
Qpipe (cfs)
= 350.00
Qovertop (cfs)
= 0.00
Veloc Dn (ft/s)
= 9.83
Veloc Up (ft/s)
= 9.96
HGL Dn (ft)
= 23.55
HGL Up (ft)
= 23.74
Hw Elev (ft)
= 26.40
Hw/D (ft)
= 1.41
Flow Regime
= Inlet Control
Hw Depth (ft)
9.65
7.65
5.65
3.65
1.65
-0.35
-2.35
a ru 13 cu [o au i5 4u 45 50 55 60 65 70 75 80 85
- Box Culvert HGL Embank
Reach (ft)

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WRIGHI'SBORO, Wr
HSG G F30
AD
36
SEAGATE� Se 3s,
HSG B ,�4\ STREAM CROSSING 1X--
---36_ } �crt N�rO1*. —"-32 \ 2s.s Ac. + — — } — 32—
3a
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-- _ -- - 6 _ _ INTERSTATE _ _ - 0 -28-
-32- _ \ - EXISTING 34 - - _ 32 -= - _ _- Q - - -23-
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CROSSING i
#I
LEGEND
\01� �, \ /, / �� \ C \ STREAM _
1 WETLANDS. CONVSERVATION STUDY LIMITS
/ / OVERLAY DISTRICT. RESOURCE
CROSSING #2 '', - ,--
/ PRESERVATION BUFFER t
LEON, Le
36� / J
HSG B/D \
/-36 / �{O i �
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off
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^�
�► - TIME OF CONCENTRATION
SOILCLASS BOUNDARY
BASIN X BASIN LABEL
XXXX AC
NODE NODE LABEL
NOTES:
I. ELEVATIONS SHOWN ARE BASED UPON COUNTY TOPO
AND WILL NOT BE USED FOR FINAL DESIGN.
2. PARCELS SHOWN ARE FROM NEW HANOVER COUNTY
GIS PARCEL DATA.
GRAPHIC SCALE
200 0 100 200 400
1 1 1 1 1
800
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3
Joe No:
J-20050.0000
DATE:
11/12/08
DRAWN:
ALG
DESIGNED:
ALG
REVIEWED:
BAR
APPROVED: J.D.R
SCALE:
I" = 200'
I� f� ` _ —3G / j / I 0 SIP • \ 5�s J \ { / / /�\
( / / ` �3�— — gyp Oh'pP
�B F.
( IN FEET )
1 inch = 200 ft.
•

rr

n Olsen Park - Phase I
Job:
20w
ti Thonra.+ . Nutton Un,ineeuino Co.
Date
10127;4008
HA Design of Stable Channels and Diversion,.
Designed hy:
CA\t
+ "y' Permissible Velocity Procedure: \ -SHAPED -- Veeetated Channel
Checked by:
JDR
User Input Duta
Calculated Vahre
Reference Data
SWALE i
Step 1: Determine the required flow capacity, Q. by estimating_ peak runoff rate for the design storm using Rational
Method (Appendix 8.03).
Design Storm: 10-Year
Drainage .Area lA): 4.21 acre
Runoff Coefficient (C): 0.11
10-Year Intensity (D: 9.48 in/hr (Te = 5 mins. From Alas 14 - NOAA)
Required Flow. Qt,t = CIA 4,39 cfs
Contributing/Upstream Q 0 cfs
Total Required Flow, Q,,,=CIA 4.39 cfs
Step 2, Check Channel permissible velocity based on lining selected, or desired velocity
(See'I able 8.05a, page 8.05.4 NCDENR Erosion and Sediment Control Planning and Design Manual)
Permissible Velocity, V,,= 3.5 ftA
Composite Runoff Coefficient
Description C A (ac) C x A
Impervious 0.95 0.05 0.0475
Lawns. sandy soil. flat 0.10 4.16 0.416
4.21 0.4635
Composite C Value =
"C values in Table 8.03b. pg 8,03.6 in NCDENR Manual
Step 3: Initial estimate of channel size -- divide the required Q by the permissible velocity to reach a "first try" estimate of channel flow area.
Channel Flow Area = 1.26 ft'-
Step 4: Check the Permissible Velocity and Channel Flow
Channel Slope: 0.0075 ft/ft
Channel Geometry: V-shaped, V-Shaped
Parabolic, or Trapezoidal
Channel Lining Vegetation: Grass -Legume Mixture
Retardance Class: "D" good stand, cut (See Table 8.05c, pg 8.05.8 in NCDENR Manual)
Channel Depth = d ft
Sideslope, Z = 16 3:1 (max) Cross -Sectional Area, A = bd + Zd2
Bottom Width, b = 0 Wetted Perimeter, P = It + 2d(Z' + 1)"'
Top Width, T = b + 2dZ Vegetal Retardance, VR = V,,*R
Hydraulic Radius, R = (bd +Z&)A(b + (2d(2' + I )0 9)
NOTE: If a channel design velocity exceeds 2.0 fps, evaluate need for temporary liner. Analysis of the shear stresses in the channel shall be calculated
to select the liner that provides protection and promotes establishment of vegetation. See step 5 if applicable.
V-Shaped -- Low Retardance
Fibwn 8.0Sh
Z Depth, A (ft-) R (ft)
VR
*n Velocity,
Check
Capacity,
Check
d (ft)
V (ft/s)
V<Vt,
Q,,,,,, (cfs)
Qm<QM:,.y
16 0.8 10.24 0.40
1.40
0.05 1.40
OK
14.3
OK
Now, Design for a higher retardance class (Class B).
Try d = 2 ft and a Trial Velocity (V,) = 3.0 ft/s
V-Shaped -- High Retardance
Figure 8.05b
, Depth, ,
Z A (W) R (ft)
V,
' *
n VR
Velocity,
Check
Capacity, Check
d (h)
V (ft/s)
V<V,,
Q„" (cfs) Q1U<QMu.v
16 2 64.00 L00
0.8
0.80 0.17
0.80
OK
51.20 OK
'Figure 8.05b, pg 8.05.5 in NCDENR Manual
Figure 8.05e. pg 8.05.7 in NCDENR Manual
Figure 8.05a, pg 8,05.2 in NCDENR Manual
Grass Lining -- Calculate n from Figure 8.05c. page 8.05.7 in NCDENR Manual
a. Determine retardance class for vegetation from Table 8.05c. page 8.05.8 in NCDENR Manual. To meet stability requirement. use retardance
for newly mowed condition (generally C or D). To determine channel capacity, use at least one retardance class higher.
Channel Summary:
V-Shaped -- Z = 16, b = 0, d = 2.0. Grade = 0.75%
Temporary Liner: Liner material is not required for Swale 1.
N:\20050\Dsgn\Stormwater\20050 Swale Calc 10-27-08.xls

I
Olsen Park - Phase I Job: 20050
Thomas ti Hutton Engineering Co. Da(e: 10127/2008
Design of Stable Channels and Diversions Designed hy: CAM
Permssible Velocity Procedure: %-SHAPED -- FeI�etu(ul Channel Checked hv: JDR
1 ser Input Data
Calculated \ alue
Reference Data
SWALE2
Step 1: Determine the required flow capacity. Q. by estimating peak runoff rate for the design storm using Rational
Method (Appendix 8.03).
Design Storm: 10-Year
Drainage Area (Ay 2.98 acre
Runoff Coefficient (C): 0.35
10-Year Intensity (1): 9.48 infltr (Tc = 5 rains. From Atlas 14 - NOAA)
Required Flow. Q,,, = CIA 9.92 efs
Contributing/Upstream Q 0 efs
Total Required Flow, Q,,, = CIA 9.92 efs
Step 2: Check Channel permissible velocity based on lining selected, or desired velocity
(See Table 8.05a, page 9.05.4 NCDENR Erosion and Sediment Control Planning and Design Manual)
Permissible Velocity, VP= 4.5 tVs
Composite Runoff Coefficient
Description C A (ac) C x A
Impervious 0.95 0.88 0.836
Lawns. sandy soil. flat 0.10 2.1 0.21
2.98 1.046
Composite C Value
•t.: uttues in table N Wh. pg 8.03.0 in NCDENR Manual
Step 3: Initial estimate of channel size -- divide the required Q by the permissible velocity to reach a "first try" estimate of channel flow area.
Channel Flow Area = 2.20 ft'
Step 4: Check the Permissible Velocity and Channel Flow
Channel Slope: 0.0075 ft/ft
Channel Geometry: V-shaped, V-Shaped
Parabolic, or Trapezoidal
Channel Lining Vegetation: Grass -Legume Mixture (Clay Mixture)
Retardance Class: "D" good stand, cut (See "fable 8.05c, pg 8.05.8 in NCDENR Manual)
Channel Depth =
d fl
Sideslope,Z=
5 3:1 ortax)
Bottom Width, b =
0
Top Width, T =
b + 2dZ
Hydraulic Radius, R =
(bd +Zd')/((b + (2d(Z2+ 1)Ili
)
Cross -Sectional Area, A = bd + Zd'
Wetted Perimeter. P = b + 2d(Z' + I )Ili
"s
Vegetal Retardance. VR = Vt,'R
NOTE: If a channel design velocity exceeds 2.0 fps. evaluate need for temporary liner. Analysis of the shear stresses in the channel shall be calculated
to select the liner that provides protection and promotes establishment of vegetation. See step 5 if applicable.
V-Shaped -- Low Retardance
HLure S.05b
t Z Depth. A (fF) t R (fl) VR n
5 1.1 6.05 0.54 2.43 0.044
Now, Design for a higher retardance class (Class B).
Try d = 4 ft and a Trial Velocity (V,) = 3.0 fl/s
Velocity, Check ' Capacity, Check
V (ft/s) V<Vt, Q., (cfs) Qm<QM.
1.94 OK 11.9 OK
V-Shaped -- High Retardance
Figure 8.05b
7 Depth. A (11 1 R (11) V, 2VR = n ' Velocity. Check Capacity, y,
Check
d (f0 V (ft/s) V<Vi' Q_ (cfs) Qw<Qst-
5 2 20.00 0.98 0.7 0.69 0.19 0.70 OK 14.00 OK
Figure 8.05b. pg 8.05.5 in NCDENR Manual
Figure 8.05c. pg 8.05.7 in NCDENR Manual
Figure 8,05a. pg 8.05.2 in NCDENR Manual
Grass Lining -- Calculate n from Figure 8.05c, page 8.05.7 in NCDENR Manual
a. Determine retardance class for vegetation from Table 8 05c. page 8.05.8 in NCDENR Manual. To meet stability requirement, use retardance
for newly mowed condition (generally C or D). To determine channel capacity. use at least one retardance class higher
Channel Summary:
V-Shaped -- Z = 5. h = 0. d = 2.0. Grade = 0.7514
Temporary Liner: Liner material is not required for Swale 2.
N:1200501Dsgn\Stormwater120050 Swale Calc 10-27-08.xls

I
_ Olsen Park - Phase 1
f Thomas S Hutton Engineering Co.
Job:
Dare:
20050
I0)'27/2008
Design of Stable Channels and Diversions
Designed by:,
CAM
Permissible Velocity Procedure: N SIIAPED -- Vegetated Channel
Checked bv:
JDR
User Input Data
Calcula(ed 1 alue
Referenee Dnta
SWALE A
` Step 1: Determine the required flow capacity. Q. by estimating peak runoff rate for the design storm using Rational
Method iAppendix 8.03).
Design Stonn: 10-Year
Drainage Area (A): 3.48 acre
Runoff Coefficient (C): 0.33
10-Year Intensity (1): 9.48 in/hr (Tc = 5 rains, From Atlas 14 - NOAA)
Required Flow. Q, = CIA 10.95 efs
ContributingXpstream Q 0 cfs
Total Required Flow, Qi„ = CIA 10.95 cfs
Step 2: Check Channel permissible velocity based on lining selected, or desired velocity
(See Table 8.05a, page 8.05.4 NCDENR Frosion and Sediment Control Planning and Design Manual)
Permissible Velocity, Vr= 3.5 ft/s
Composite Runoff Coefficient
Description C A (act C x A
Impervious 0.95 0.95 0.9025
Lawns, sandy soil. Flat 0.10 2.53 0.253
3.48 1.1555
Composite C Value = 0.33
`l.' values in Table 14.03h, pg 8.03.6 in NCDENR Manual
Step 3: Initial estimate of channel size -- divide the required Q by the permissible velocity to reach n "first try" estimate of channel Flow area.
Channel Flow Area = 3.13 ft'
Step 4: Check the Permissible Velocity and Channel Flow
Channel Slope: 0.005 ft/ft
Channel Geometry: V-shaped, V-Shaped
Parabolic, or Trapezoidal
Channel Lining Vegetation: Grass -Legume Mixture
Retardance Class: "D" good stand, cut (See Table 8.05c. pg 8.05.8 in NCDENR Manual)
Channel Depth = d ft
Sideslope. Z= 7 3:1 (max) Cross -Sectional Area, A= bd+Zd'-
Bottom Width, b = 0 Wetted Perimeter, P = b + 2d(Z' + 1)"'
Top Width. T= b+2dZ Vegetal Retardance, VR = Vi,°R
Hydraulic Radius. R= (bd+Zd')/((b+(2d(Z'+11°''1
NOTE: If a channel design velocity exceeds 2.0 fps. evaluate need for temporary liner. Analysis of the shear stresses in the channel shall be calculated
to select the liner that provides protection and promotes establishment of vegetation. See step 5 if applicable.
V-Shaped -- Low Retardance
figure A.05b
i Z Depth, A (ft-) R (ft) VR err , Velocity. Check ' Capacity, Check
d (ft) V (ft/s) V<Vp Qm (efs) Qa,<Qm..
7 1.1 8.47 0.54 1.91 0.045 1.56 OK 13.2 OK
Now, Design for a higher retardance class (Class B).
Try d = 2 ft and a Trial Velocity (V,) = 3.0 ft/s
V-Shaped -- High Retardance
Figure 8.05b
, Z Depth, A (Fr') R ff0 V, ' VR * n Velocity, Check Capacity. Check
d (ft) Velocity,
(ft/s) V<V1, Q, (cfs) Qm<QM..
7 2 28.00 0.99 0.4 0.40 0.28 0.40 OK 11.20 OK
Figure 8.05b. pg 8.05.5 in NCDENR Manual
"Figure 8.05c, pg 8.05.7 in NCDENR Manual
Figure 8.05a, pg 8.05.2 in NCDENR Manual
Grass Lining -- Calculate n from Figure 8.05c. page 8.05.7 in NC'DI NR Manual
a- Determine retardance class for vegetation front'rahle 8.05c. page 8.05.8 in .NCDENR Manual. To meet stability requirement, use retardance
for newly mowed condition (generally C or D). To determine channel capacity. use at least one retardance class higher.
Channel Summary:
V-Shaped -- Z = 7. b = 0. 0 = 2.0. Grade = 0.50%
Temporary Liner: Liner material is not required for Swale A.
N:1200500sgnlStormwater\220050 Swale Cale 10-27-08.xls

C)Isen Park - Phase I Job: 20050
Thomas fi Mutton Engineering Co. Date: 10/27/2008
i.
Design of Stable Channels and Diversions Designed by: CAN
Permissible Velociry Procedure: V-SILIPEJ) - Vegetated Channel Checked by: JDR
User Input Data
Calculated value
Reference Data
SWALE B
Step 1: Determine the required flow capacity. Q. by estimating peak runoff rate for the design stoma using Rational
Method ( Appendix 8.03).
Design Storm: 10-Year
Drainage Area (A): 0.35 acre
Runoff Coefficient (CY 0.34
10-Year Intensity (1): 9.48 in/hr (Te = 5 mins. From Atlas Id - NOAA)
Required Flow, Q,,, = CIA 1.14 cfs
C'ontributing/12psiream Q 0 cfs
Total Required Flow, Q,,, = CIA 1.14 cfs
Step 2: Check Channel permissible velocity based on lining selected, or desired velocity
(See'rable 8.05a. page 8,05.4 NCDENR Erosion and Sediment Control Planningand Design Manual)
Permissible Velocity. Vp= 3.5 ft/s
Composite Runoff Coefficient
Description C A (ac) C x A
Impervious 0.95 0.1 0.095
Lawns, sandy soil. flat 0.10 0.25 0.025
0.35 0.12
Composite C Value= 0.34
°C values in Table 8.03b. pg 9,03.6 in NCDENR Manual
Step 3: Initial estimate of channel size -- divide the required Q by the permissible velocity to reach a "first try" estimate of channel flow area.
Channel Flow Area = 0.33 W
Step 4: Check the Permissible Velocity and Channel Flow
Channel Slope: 0.018 ft/ft
Channel Geometry: V-shaped, V-Shaped
Parabolic, or Trapezoidal
Channel Lining Vegetation: Gress -Legume Mixture
Retardance Class: "D" good stand, cut
(See Table 8.05c. pg 8.05.8 in NCDENR Manual)
Channel Depth = d ft
Sideslope, Z= 9 3:1 (max)
Cross -Sectional Area, A = bd+Zd'
Bottom Width, b = 0
Wetted Perimeter, P = b + 2d(Z2+ 1)° `
Top Width. T= b+2dZ
Vegetal Retardance. VR= Vi;'R
Hydraulic Radius. R= (bd+Zd2A(b+(2d(Z'-+I)05)
NOTE: If a channel design velocity exceeds 2.0 fps, evaluate need for temporary liner. Analysis of the shear stresses in the channel shall be calculated
to select the liner that provides protection and promotes establishment of vegetation. See step 5 if applicable.
V-Shaped -- Low Retardauce
F)gume S.05h
Z Depth, A (Ft') R (ft) ' VR * n 3 Velocity,
Check
3 Capacity,
Check
! d (ft) V (ft/s)
V<VP
Q,,,,, (cfs)
Qm<Qm.,.
9 0.5 2.25 0.25 0.87 0.06 1.32
OK
3.0
OK
INow, Design for a higher relardance class (Class B).
Try d = I ft and a Trial Velocity (V,) = 2.0 ft/s
V-Shaped -- High Retardance
r-'ieure B.DSb
Z Depth. A (ft-) R 00 V, '- VR * n
Velocity,
Check
Capacity, Check
d (ft)
V (ft/s)
_
V<Vi,
Q,mx (efS) Qln<QMax
9 1 9,00 0.50 0.4 0.20 0.28
0.40
OK
3.60 OK
Figure 8.05b. pg 8.05.5 in NCDENR Manual
Figure 8.05c, pg 8.05.7 in NCDENR Manual
L Figure 8.05a. pg 8.052 in NCDENR Manual
Grass Lining -- Calculate n from Figure 8.05c, page 8.05.7 in NCDENR Manual
a. Determine retardance class for vegetation from Table 8.05c, page 8.05A in NCDENR Manual.
To meet stability requirement. use reiardance
for newly mowed condition (generally C or D). To determine channel capacity. use at least one retardance class higher.
F
Channel Summary:
V-Shaped -- 7_ = 9. b = 0. d = 1.0. Grade = 1.8%
Temporary Liner: Liner material is not required for Swale B.
N:1200501DsgnlStormwater120050 Swale Calc 10-27-08.xls

(' Olsen Park - Phase 1
j 'rhontas & Hutton Engineering Co.
Job:
Date:
2W50
10/27i2008
11 Design of Stable Channels and Diversions
Designed by:
CAM
+� Permissible Velocity Procedure: V-SHAPFD - Vegetated Channel
Checked by;
JDR
I ser Input Duta
Calculated clue
Reference Datu
SWALE C
Step 1: Determine the required flow capacity. Q. by estimating peak runoff rate for the design storm using Rational
Method (Appendix 8.031.
Design Storm: 10-Year
Drainage Area (A): 1.55 acre
Runoff Coefficient (C): 0.80
10-Year Intensity (1): 9.48 in/hr (Tc = 5 mins, From Atlas 14 - NOAA)
Required Flow, Q,,, = CIA 11.70 cfs
Contributing/Upstream Q 0 cfs
Total Required Flow, Q,,, = CIA 11.70 cfs
Step 2: Check Channel permissible velocity based on lining selected, or desired velocity
(see Table 8.05a. page 8.05.4 NCDENR Erosion and Sediment Control Planning and Design Manual)
Permissible Velocity, Vr, = 3.5 ft/s
Composite Runoff Coefficient
Description C A (ac)
C x A
Impervious 0.95
1.27
1.2065
[awns, sandy soil, flat 0.10
0.28
0.028
1.55
1.2345
Composite C Value
C values in Table 8.03h, pg 9.03.6 in NCDENR Manual
Step 3: Initial estimate of channel size -- divide the required Q by the permissible velocity to reach a "first try" estimate of channel flow area.
Channel Flow Area = 3.34 R2
Step 4: Check the Permissible Velocity and Channel Flow
Channel Slope: 0.011 AM
Channel Geometry: V-shaped, V-Shaped
Parabolic, or Trapezoidal
Channel Lining Vegetation: Grass -Legume Mixture
Retardance Class: "D" good stand, cut (See Table 8.05c. pg 8.05.8 in NCDENR Manual)
Channel Depth = d ft
Sideslope, Z = 15 3:1 (max) Cross -Sectional Area, A = bd + Zd'
Bottom Width, b = 0 Wetted Perimeter. P = b + 2d(Z' + 1)D.,
Top Width, T = b + 2dZ Vegetal Retardance. VR = Vi *R
Hydraulic Radius, R = (bd +Zd'V((b + (2d(Z' + 1 )r's)
NOTE: If a channel design velocity exceeds 2.0 fps, evaluate need for temporary liner. Analysis of the shear stresses in the channel shall be calculated
to select the liner that provides protection and promotes establishment of vegetation. See step 5 if applicable.
V-Shaped -- Low Retardance
Z Depth, A (ft) r R (ft) ' VR n ' Velocity, Check ' Capacity, Check
d (ft) V (ft(s) V<Vp Q_ (cfs) Qnr<Qm.x
15 0.8 9.60 0.40 1.40 0.051 1.66 OK 15.9 OK
1 Now, Design for a higher retardance class (Class B).
Try d = U It and a Trial Velocity (V,) = 3.0 ft/s
V-Shaped -- High Retardance
Fieure 8,05b
1 Depth, i Velocity, Check Capacity, Check
Z d (ft) A (ft') R (.f0 V, VR n V (ft/s) V<Vr QM..
Q„u, (cfs) Qui<
I15 1.5 33.75 0.75 0.4 0.30 0.31 0.40 OK 13.50 OK
'Figure 8.05b. pg 8.05.5 in NCDENR Manual
' Figure 8.05c, pg 8.05.7 in NCDENR Manual
Figure 8.05a, pg 8.05 2 in NCDENR Manual
Grass Lining -- Calculate n from Figure 8.05c, page 8 05.7 in NCDENR Manual
a. Determine retardance class for vegetation from Table 8.05c. page 9.05.8 in NCDENR Manual. To meet stability requirement. use retardance
for newly mowed condition (generally C or D). To determine channel capacity, use at least one retarrlance class higher.
- Channel Summary:
V-Shaped -- Z = 15, b = 0, d = 1.5. Cnnade = 1.1 %
Temporary Liner: Liner material is not required for Swale C.
N:\20050\Dsgn4Stortttwater120050 Swale Calc 10-27-08.xls

i
Olsen Park - Plume 1
'Thomas R Huron Engineering Co.
Job:
Date:
20050
10/27/2008
Design of Stable Chamnels and Diversions
Designed by:
CAM
Permissible Velocity Procedure: V-SH.%PFD -- Vegetated ('hannel
Checked bv:
JDR
User Input Data
Calculated \ ulue
Reference Data
SWALE D
Step 1: Determine the required flow capacity. Q, by estimating peak runoff rate for the design storm using Rational
Method tAppendix 8.03).
Design Storm: 10-Year
Drainage Area (A): 1.55 acre
Runoff Coefficient (C): 0.80
10-Year Intensity (1): 9.48 in/hr (Tc = 5 mins, From Atlas 14 NOAA)
Required Flow. Qi„ = CIA 11.70 cfs
Contributing/Upstream Q 0 cfs
Total Required Flow. Q i„ = CIA 11.70 cfs
Step 2: Check Channel permissible velocity based on lining selected, or desired velocity
(See Table 8.05a, page 8.05.4 NCDENR Er)sion and Sediment Control Planning and Design Manual)
Permissible Velocity. V1,= 3.5 ft/s
Composite Runoff Coefficient
Description C A (ac)
C x A
Impervious 0.95 1.27
1.2065
Lawns, sandy soil. Oat 0.10 0.28
0.028
1.55
1.2345
Composite C Value = 0.80
'Cvalues in "table 8.03b, pg 8.03.6 in NCDENR tvtanual
Step 3: Initial estimate of channel size -- divide the required Q by the permissible velocity to reach a "first try" estimate of channel flow area.
Channel Flow Area = 3.34 W
Step 4: Check the Permissible Velocity and Channel Flow
Channel Slope: 0.011 ft/ft
Channel Geometry: V-shaped, V-Shaped
Parabolic, or Trapezoidal
Channel Lining Vegetation: Grass -Legume Mixture
Retardance Class: "D" goal stand, cut ( See Table 8.05c, pg 8.05.8 in NCDENR Manual)
Channel Depth = d ft
Sideslope.'7..= 15 3:1Imax) Cross -Sectional Area, A= bd+Zd'
Bottom Width, b = 0 Wetted Perimeter, P = b + 2d(2' + I )" `
Top Width, T = b+2dZ Vegetal Retardance. VR = V xR
Hydraulic Radius. R= (bd+Zd')/l(b+(2d(Z'-+I)")
NOTE: If a channel design velocity exceeds 2.0 fps, evaluate need for temporary liner. Analysis of the shear stresses in the channel shall be calculated
to select the liner that provides protection and promotes establishment of vegetation. See step 5 if applicable.
V-Shaped -- Low Retardance
I iLtue 8.051
Z Depth, I A (fr') I R (fU ' VR n ' Velocity. Check 'I Capacity. Check
d (ft) V (ft/s) V<Vr Q_ (cfs) Qn,<QAL,.
15 0.8 9.60 0.40 1.40 0.051 1.66 OK 15.9 OK
Now, Design for a higher relardance class (Class B).
Try d = 2 ft and a Trial Velocity (V,) = 3.0 R/s
V-Shaped -- High Retardance
Figure 8.05b
Z Depth, I A (ft') R Ift) V� ' VR n , Velocity. Check Capacity, Check
d (fti
V (ft/s) V<Vr QMs (cfs) Qr,<QM:u
15 1.5 33.75 0.75 0.5 0.37 0.28 0.50 OK 16.88 OK
Figure 8.05b, pg 8.05.5 in NCDENR Manual
' Figure 8.05e, pg 8.05.7 in NCDENR Manual
1 Figure 8.05a, pg 8.05 2 in NCDENR Manual Grass Lining -- Calculate n from Figure 8.05c. page 8.05.7 in N('DENR Manual
a. Determine retardance class for vegetation from Table 8.05c, page 8.05.8 in NC'Dr.NR Manual. To meet stability requirement. use relanlance
for newly mowed condition (generally C or D). To determine channel capacity. use at least one reiaaiance class higher.
Channel Summary:
V-Shaped -- Z = 15. b = 0. d = 1.5. Grade = 1.19.
Temporary Liner: Liner material is not required for Swale D.
N:1200501DsgnlStormwaterl2O050 Swale Calc 10-27-08.xls

/µYfgTY L/J Olsen Park - Phase 1 Job: 200%
Thomas & Huuon Engineering Co Date: 10/2712008
Design of Stable Channels and Diversions Designed by: CAM
Permissible Velocit) Procedure. V-SII.%I'FD - Vegetated Channel Checked by: JDR
User Input Data
Calculated Value
Reference Data
SWALE E
Step I: Determine the required flow capacity. Q. by estimating peak runoff rate for the design storm using Rational
Method (Appendix 8.03).
Design Stonn: 10-Year
Drainage Area (A): 0.35 acre
RunoffCoefficient (C): 0.34
10-Year Intensity (D: 9.48 in/hr (Te = 5 mins. From Atlas 14 - NOAA)
Required Flow, Q „ = CIA 1.14 cfs
Contributing/Upstream Q 0 cfs
Total Required Flow. Q„ , = CIA 1.14 cfs
Step 2: Check Channel permissible velocity based on lining selected. or desired velocity
(See Table 8.05a, page 8.05.4 NCDENR Erosion and Sediment Control Planning and Design Manual)
Permissible Velocity, Vr,= 3.5 ft/s
Composite Runoff Coefficient
Description C A (ae) C x A
Impervious 0.95 0.1 0.095
Lawns, sandy soil, flat 0.10 0.25 0.025
0.35 0.12
Composite C Value
^C slues in Table 8.03b, pg 8.03.6 in NCDENR Manual
Step 3: initial estimate of channel size -- divide the required Q by the permissible velocity to reach a "first try" estimate of channel flow area.
Channel Flow Area = 0.33 ft'
Step 4: Check the Permissible Velocity and Channel Flow
Channel Slope: 0.018 ft/ft
Channel Geometry: V-shaped, V-Shaped
Parabolic. or Trapezoidal
Channel Lining Vegetation: Grass -Legume Mixture
Retmdance Class: "D" gaud staml, cut (See Table 8.05c, pg 8.05.8 in NCDENR Manual )
Channel Depth = d ft
Sideslope, Z = 9 3:1 (max)
Bottom Width. b = 0
Top Width. T = b + 2dZ
Hydraulic Radius. R = (bd +Zd2)/((b + (.2d(7' + 1)0s)
Cross -Sectional Area, A = bd + Zd"
Wetted Perimeter, P = b + 2d(2' + 11°
Vegetal Retardance, VR = V,,*R
NOTE: If a channel design velocity exceeds 2.0 fps, evaluate need for temporary liner. Analysis of the shear stresses in the channel shall he calculated
to select the liner that provides protection and promotes establishment of vegetation. See step 5 if applicable.
V-Shaped -- Low Retardance
I Figure RASb
+I , Z Depth, i A (ft') t R (ft) ' VR * ft
d (h)
9 0.5 2.25 0.25 0.87 0.06
Now, Design for a higher relardance loss (Class B).
Try d =1 ft and a Trial Velocity (V,) = 2.0 ft/s
Velocity, Check ' Capacity, Check
V (f ts) V < VP Q_ (cfs) Qw<Qwo.
1.32 OK 3.0 OK
V-Shaped -- High Retardance
Figure 8.05b
Depth. Velocity, Check Capacity, Check
Z d (f) A Ut--) R lfU V, ' VR n V MIS) r Q.- (cfs) Qrn
Y < Y < QM..
9 1.5 20.25 0.75 1 0.75 0.17 1.00 OK 20.25 OK
'Figure 8.05b, pg 8.05.5 in NCDENR Manual
Figure 8.05c, pg 8.05.7 in NCDENR Manual
Figure 8.05a. pg 8.05.2 in NCDENR Manual
Grass Lining -- Calculate n from Figure 8.05c, page 8.05.7 in NCDENR Manual
a. Determine retardance class for vegetation from Table 8.05c. page 8.05.9 in NCDENR Slanual. to meet stability requirement, use retardance
for newly mowed condition (generally C or D). To determine channel capacity, use at least one fetardance class higher.
Channel Summary .
V-Shaped -- Z = 9, b = 0, d = 1.5. Grade = 1.8%
Temporary, Liner: Liner material is not required for Swale E.
e
LN:\20050\Dsgn\Stomlwater\2OOSO Swale Calc 10-27-08.xls

I
Olsen Park - Phase 1
Thomas & Hutton Engineering Co.
Job:
Date:
20050
12/4/'_008
1`
Design of Stable Channels and Diversions
Designed by:
CAM
Permissible Velocity Procedure: t""SHAPED -- V,gctatrd Channel
Checked bv:
JDR
User Input Data
Calculated V:Ilue
Reference Data
AL F
Step 1: Determine the required Flow capacity. Q. by estimating peak runoff rate for the design storm using Rational
Method (Appendix 8.031.
Design Storm: 10-Year
Drainage Area (A): 1.89 acre
Runoff Coefficient (C): 0.10
10-Year Intensiry (1): 9.48 in/hr (Tc = 5 ruins. From Atlas 14 NOAA)
Required Flow, Q „= CIA 1.79 cfs
Conuibuting/Upsneam Q 0 cfs
Total Required Flow, Qt„ = CIA 1.79 cfs
Step 2: Check Channel permissible velocity based on lining selected, or desired velocity
(See Table 8.05a, page 8.05.4 NCDENR Erosion and Sediment Control Planning and Design Manual)
Permissible Velocity, Vr= 3.5 R/s
Composite Runoff Coefficient
Description C A (ac) C x A
Lawns, sandy soil, flat 0.10 L89 0.189
0
1.89 0.189
Composite C Value
`Cvalues in Table 8.031), pg 8.03.6 in NCDENR Manual
Step 3: Initial estimate of channel size -- divide the required Q by the permissible velocity to reach a "first try" estimate of channel flow area.
Channel Flow Area = 0.51 ft'-
Step 4: Check the Permissible Velocity and Channel Flow
Channel Slope: 0.008 ft/ft
Channel Geometry: V-shaped,
Parabolic, or Trapezoidal V-Shaped
Channel Lining Vegetation: Grass -Legume Mixture
Retardance Class: "D" good stand, cut (Sce'rable 8.05c. pg 8.05.8 in NCDENR Manual)
Channel Depth = d ft
Sideslope, Z = 5 3:1 (max) Cross -Sectional Area. A = bd +Zd'
Bottom Width, b = 0 Wetted Perimeter. P = b + 2d(Z' + If'
Top Width, T = b+ 2dZ Vegetal Retardance, VR = VP'R
Hydraulic Radius. R= (bd+Zd')/((b+(2d(Z'-+1)0
NOTE: If a channel design velocity exceeds 2.0 fps, evaluate need for temporary liner. Analysis of the shear stresses in the channel shall be calculated
to select the liner that provides protection and promotes establishment of vegetation. See step 5 if applicable.
V-Shaped -- Low Retardance
Iimure 9.01
Depth. r ' Velocity. Check `Capacity. Check
Z (ft) d (ft) A R (ft) VR n V (ems) V<Vr Q_ (cfs) Qu,<Qm.
5 0.8 3.20 0.39 1.37 0.051 1.40 OK 4.5 OK
Now, Design for a higher retardance class (Class B).
Try d = 2 ft and a Trial Velocity (V,) = 3.0 ft/s
V-Shaped -- High Retardance
Figure 8.05h
Depth. ' Velocity. Check `('apacity. Check
Z d (ft) (ft') R (ft) V, VR '`n V (f/s) V<VN QOeA (cfs) Qlu<Qsi..
5 1.5 11.25 0.74 0.4 0.29 0.31 0.40 OK 4.50 OK
'Figure 8.05b, pg 8.05.5 in NCDENR Manual
' Figure 8.05c. pg 8.05.7 in NCDENR Manual
Figure 8.05a, pg 8.05.2 in NCDENR Manual
Grass Lining -- Calculate n from Figure 8.05c, page 8.05.7 in NCDENR Manual
a. Determine retardance class for vegetation from Table 8.05c, page 8 05.9 in NCDENR Manual. To meet stability requirement. use retardance
for newly stowed condition (generally C or D). To determine channel capacity. use at least one retardance class higher.
Channel Summary:
V-Shaped-- Z = 5. b = 0. d = 1.5. Grade = 0.8%
Temporary Liner: Liner material is not required for Swale F.
N:120050\DsgnlStormwateA20050 Swale Cale 10-27-08.xls

Olsen Park - Phase 1
fhontas & Hutton Engineering Co.
)oh:
Date:
20050
10127/2008
Design of Stable Channels and Diversions
Designed by:
CAM
Permissible Velocity Procedure. V-SILV'FD -- Vegetated Channel
Checked b :
)DR
user Input Data
Calculated \ alue
Referrnm Data
SWALE G
Step 1: Determine the required Flow capacity. Q. by estimating peak runoff rate for the design storm using Rational
Method (Appendix 8.03).
Design Storm: 10-Year
Drainage Area (AI: 2.3 acre
Runoff Coefficient (C): 0.14
10-Year Intensity (I): 9.48 in/hr (Te = 5 rains. From Atlas 14 - NOAA)
Required Flow. Q,,; = CIA 2.99 efs
Contributing/Upstreanm Q 0 cfs
Total Required Flow, Q11 = CIA 2.99 cfs
Step 2: Check Channel permissible velocity based on lining selected, or desired velocity
(see fable 8.05a, page 8.05.4 NCDENR Erosion and Sediment Control Planning and Design Manual)
Permissible Velocity. Vr, = 3.5 f /s
Composite Runoff Coefficient
Description C .A (ac) Cx A
Impervious 0.95 0.1 0.095
Lawns, sandy soil. Flat 0.10 2.2 0.22
2.3 0.315
Composite C Value = 0.14
•C' values in Table 8.03b, pg 8.03.6 in NCDENR Manual
Step 3: Initial estimate of channel size -- divide the required Q by the permissible velocity to reach a "first try" estimate of channel Flow area.
Channel Flow Area = 0.85 ft'-
Step 4: Check the Permissible Velocity and Channel Flow
Channel Slope: 0.01 ft/ft
Channel Geometry: V-shaped, V_ghapxvl
Parabolic, or Trapezoidal
Channel Lining Vegetation: Crass -Legume Mixture
Retardance Class: "D" gootl stamp. cut (See Table 8.05c, py 8.05.9 in NCDENR Manual)
Channel Depth =
d ft
Sideslope, Z =
10 3:1 (max) Cross -Sectional Area, A = bd+Zd'
Bottom Width, b =
0 Wetted Perimeter. P = b + 2d(Z.' + I;"
Top Width. T =
b + 2dZ Vegetal Retardance. VR = Vr:°R
Hydraulic Radius. R=
(bd+Zd')/((b+(2ti(Z'+I1 sl
NOTE: if a channel design velocity exceeds 2.0 fps. evaluate need for temporary liner. Analysis of the shear stresses in the channel shall be calculated
to select the liner that provides protection and promotes establishment of vegetation. See step 5 if applicable.
V-Shaped -- Low Retardance
Pignut 1 ((611
Depth, * Velocity, Check 'Capacity, Check
Z d (it) A (ft') R (ft) 'VR n V (ft/s) V<Vr Q,"s (efs) Qa<QM..
10 0.8 6.40 0.40 1.39 0.051 1.58 OK 10.1 OK
Now, Design for a higher retardance class (Class B).
Try d = 2 ft and a Trial Velocity (V) = 3.0 R/s
VShaped -- High Retardance
Figure 8.05h
Z Depth, r A (ft-) ' R (fq V� ' VR =n Velocity, Check "Capacity, Check
d (ft) V (ft/5) V<Vr, Q,,,,, (cfs) Qua<Qxla.
10 1.5 22.50 0.75 0.4 0.30 0.31 0.40 OK 9.00 OK
Figure 8.05b, pg 8.05.5 in NCDENR Manual
- Figure 8.05c. pg 8.05.7 in NCDENR Manual
`Figure 8.05a, pg 8.05.2 in NCDENR Manual
Grass Lining -- Calculate n from Figure 8.05c. page 8.05.7 in NCDENR Manual
a. Determine retardance class for vegetation from Table 8.05c, page 8.05.8 in NC'DI NR Manual. To meet stability requirement. use retardance
for newly mowed condition (generally C or D). To determine channel capacity. use at least one retardance class higher.
I Channel Summary:
V Shaped -- Z = 10. It = 0, d = 15. Grade = 1.0%
Temporary Liner: Liner material is not required for Swale G.
N:\20050\Dsgn\Stormwater\20050 Swale C'alc 10-27-08.xis

r
�-
f

I
sen Park = Phase 1 Job: 20050
Thomas &Hutton Engineering Co.00,
Date: 1/5/2009
Sediment Basin & Trap Design Considerations Designed by: CAM
` Checked by: JDR
I SEDIMENT TRAP #1
Check Capacity of Trap
Required Capacity:
Minimum Volume = 3600 ft' per acre of disturbed area
where: Disturbed area (ac) = 3.43
` Min. Volume = 12348 ft 3
Minimum Surface Area = 435 sf per cfs of Qi„ peak inflow
where: Q„) = 8.03 cfs (from Swale calculations)
Min Surface Area = 3493.05 ft2
Design Dimensions: Width = 50 ft
Length = 70 ft
Depth = 3.5 ft
Volume Provided = 12355 ft;
Surface Area Provided= 3500 ft 2
SEDIMENT TRAP #2
Check Capacity of Trap
Required Capacity:
Minimum Volume = 3600 ft3 per acre of disturbed area
where: Disturbed area (ac) = 1.49
Min. Volume = 5364 fO
Minimum Surface Area = 43.5 sf per cfs of Q„) peak inflow
where: Q,,) = 4.78 cfs (from swale calculations)
Min Surface Area = 2079.3 ft'
Design Dimensions: Width =
42 ft
Length =
50 ft
Depth =
2.6 ft
Volume Provided =
5376 ft;
Surface Area Provided=
2100 ft2

Olsen Park - Phase 1
Y, Thomas & Hutton Engineering Co.
Level Spreader Design Considerations
R�No Supplement Calculations - Level Sprei
Level Spreader #1
Job:
20050
Date:
2/ 19/2009
Designed by:
CAM
Checked Bv:
JDR
Level Spreader Receiving Flow from a BMP
Type of BMP: Depressed area for flood control designed with 15" Drainage Pipe
10-Year Flow (Q) to Level Spreader: 7.0 cfs**
**Note: The 10-Year flow from the 15" RCP drainage pipe was calculated in ICPR. Reference Section 2.3, sheet labeled
"Node Max/Min Report" of this report.
Level Spreader #2
Level Spreader Receiving Flow from a BMP
Type of BMP: Wet Pond with Control Structure for flood control
10-Year Flow (Q) to Level Spreader: 2.0 cfs**
*'"Note: The 10-Year flow from the Control Structure was calculated in ICPR. Reference Section 2.3, sheet labeled
"Node Max/Min Report" of this report.
N:\20050\Dsgn\Stormwater\20050 DENR Level Spreader.xlsx Page 1 of 1

r
r
I
I

YA Olsen Park - Phase 1Job: 20050
}, Thomas f Hutton Lngineering Co. Date 211712Ix)9
Design Stable Swales and Diversions Designed by CAM
`'�c-Fw,i•'3 - NHC Calculations - Grassed Sw ale Design C'hec6ed 13v: JDR
Swale #1
Determine 25-fear and IM-fear Flow for Channel
Use Rational %lethod for 25-Year blow:
Flow: Q = CIA
Where: Q = Design Flow i cfs I
C = Runui7 Coefficient
1= 25-Year Rainfall Intensity
Area Description
Table40-1
Runutl'
Coefficient.0
Area
(ac)
Impervious
0.95
0.05
Lawn, Flat. Sandy
0.1
4.16
Composite RunoffCoel'Iicient.C= (I.11
({ Time of Concentration
Use Tc =
5.00 min
I1„(in Ihr)=
10.70
Design Flow
C =
0.11
1,5 =
10.70
A =
4.21 acre
Q_, =
4.96 cis
Estimate Channel Size
Estimated Channel Area. A (112) =
1.42
Guesses for Actual Channel
Area:
Sideslope. M:I =
16
Channel Depths d =
3
MmomWidth, 13(11)=
0
Actual Area (It') =
144.00 OK
Hydraulic Radius. R (0) =
1.50
Determine Mannine's n value:
(Sec Table 40-I, pg. 40-3 in NHC Sulrmyaler Manual I
I,w) (in / hr) = 12.56
C= 0.11
1,,,,, = 12.56
A = 4.21 acre
Qt„a= 5.82 cis
Retardance Class (Table 60-4) =
D
Retardance Class (o Use with Graph on Page 60-5 NHC Manual =
H
Penmissable Velocity (lUs) =
3.5 From Table 60-1
Hydraulic Radius (It)=
IN)
V ` R (Far Use on Graph on Page 60-5 =
5.24
Mannins n value from Graph on Page 611-5 =
0.035
LN:\20050\Dsgn\Stormwater\20050 25-yr NHC Swale Calc.xlsx Page 1 of 2

Olsen Park - Phase J
Thomas S Hutton Engineering Co.
2 Design Stable Swales and Diversions
a,..0 INHC. Calculmions - Grassed Swale D
Swale #1
Determine Depth of Flow in Swale
Max Velocity can he determined from Manning's Equa ion:
However, area and hydraulic radius are not known
.[bv NLsnniry [yuati �sr cml lie mamd aw
J.984
_ It A R•
i1-hery l " 1'cak di.chna eh+tf-rf—nO ltfE)
e NleM4"r4AU0fVVWS tnffivlenl(dimerssitmkxv!
A - ('auMl+cthnstl area of gor.' (eq All. Cho, atoa 111e." Agh which fl,rw
lakas Putty t.s NI. j
R - Hydraulic radLra (ft, found by dwtdi" .Tea c tw real area, A
(aq fl), by wetted parimmas, Is (ft) fart hwe wk
5 - LvrsJ-Itudir.al slope of the invtaf of the channel (ft taa/ft
F4P""
DiaAenm ,d a er.1-1del ehasu>N'
M
M
♦ B
M w gi vens d by chasu.el side slope .rcyuir envervts, which am typiedly i 1 4M-.V
wdesa alhervnise 91peri6ed m this manual.
Area can he expressed as:
A=By+Myz
Hydraulic Radius, R can he expressed as:
R A
P
where P is:
P=B+2y0+AV)"
Per the near ofmWna aMsre the ♦atta61w1 havo tha C-11-wing-wa-In(pc (-I- a der to
Figure.%.kle
A Cs —vactiwlal anmof aox• (ty N
8 - �WNom width eF Lt.. thalr i0)
M + Nd"h low fatty 41,11 Fxatra.121/11l vwtleaF) t:4Mn caned l�ineraA
.idr sfpRr srqufnw.euh9
p . wetud petimtter (fq
R llydraulte radnu (R)
X - Depth of ttrw (n)
All variables arc known in Manning's Equation except y (found in AR'""t term)
Rearranging Mannings Hqualion
AR""=Q:n/(1.49*.Su.`)=(N:ky+M"y') 1(131.ly+M"y2)1(11+I.y(1+M2)`)i
Q2� (cfs)= 4.96 Ql". (efs)= 5.82
Longitudinal Slope= 0.0075 Longitudinal Slope= 0.0075
Manning's n = D.035 Manning's n = 0.035
AR'""'= 1.35 AR '""'= 1.58
AR v' li y M:1 A
25-Year 0.(x) (1.471 16.:1(1 3.55
1, Year (I.II(1 (1.499 16.U0 3 J9
Calculated Depth off -low (fl) = 0.47
Average Swale Depth 0-1) = 2.0 Ok, Swale meets design capacity
.lah: 2II050
Dale. 2/17/2009
Designed hy: CAM
Checked By: JDR
L N:\20050\Dsgn\Stormwater\20050 25-yr NHC Swale Calc.xlsx Page 2 of 2

I a Olsen Park - Phase I Job: _10050
Thomas & Hutton Engineering Co. Date: 2!I'.l_U09
2 Design Stable Swales and Di%ersions Designed by: CAM
NHC Calculations - Graswd S%:ale Design Checked Bv: JDR
Swale #2
L
Determine 29-Year untl 100-fear Flow ror Channel
Use Rational Method for 25-Year Flow:
Flow: Q = CIA
Where: Q = Design Flow (cf.,)
C = Runoff Coefficient
I = 25-Year Rainfall Intensity
Area Description
Table40-1
Runoff
Coefficient,C
Area
lac)
Impervious
0.95
0.88
Lawn, Flat. Sandy
0.1
2.10
Composite Runoff Coefficient. C = 0.35
Time or Concentration
Use Te =
5.00 min
Is (in I hr) _
10.70
Design Flow
C =
0.35
1,s =
10.70
A =
2.98 acre
Q25 =
I1.19 cfs
Estimate Channel Size
Estimated Channel Area. A W) =
3.20
Guesses for Actual Channel
Area:
Sideslope, MA =
5
Channel Depth, d =
3
Bottom Width. B (ft) =
0
Actual Area (ft) =
45.00 OK
Hydraulic Radius. R (ft) =
1.47
Determine Manning's n value:
tSee Table 10-I, pg. 40-3 in NIK' Stormwver Manuals
1,,,,, (in / hr) = 12.56
C = 0.35
1,,,, = 12.56
A = 2.98 acre
Q,p = 13.14 cfs
Retardance Class (Table 60-4) =
D
Retatdance Class to Use with Graph on Page 60-5 NHC Manual =
E
Permissable Velocity (ft/s) =
3.5 From Table 60-1
Hydraulic Radius (ft) =
1.47
V °' R (For Use on Graph on Page 60-5 =
5.15
Manning's n value from Graph on Page 60-5 =
0.035
N:\20050\Dsgn\Stormwater\20050 25-yr NHC Swale Calc.xlsx Page 1 of 2

u
}
Olsen Park - Phase 1
Job:
2(k)50
9.
Thomas S Hutton Engineering Co.
Date:
2/I7/2W9
r°
Design Stable Swales and Diversions
Designed by:
CA51
4eanl4a
NHC Calculations - Orashd Swale Design
Checked BI:
JDR
Swale #2
Determine Depth of Flow in Swale
Max Velocity can be determined from Mannincs Equation
However. area and hvxlraulic radius are not known
file M.".11irg Egmfitwn Carl tY NtaNd QT:
i."itsO
iv .
n A Re.-: !; s
%Vh—, ll ++
reakdvchargp•h ttN•fhannel(rf3)
A
itatlllXRrl� I uK,hnta9 4.,fflelenl {i11M1•IWh mte e3)
.rA
Cr.,:e.. vI:.Inal atne . w &Iw (py Fq, thI an•a ihmudh wlhkll fl~
Ilk"I,Lxv I h-'"
R
I Wdraulle radio. ktgji and by dmdm%cnuc•..ert xmA ar A
Isq fl), by —t d peri-~, P (ft) I— Waal
s -
1-.I> Oru i:lmf �Iope of thL irnreR ck the channel Oft (ntli R run).
F11pN f-3
t)faµram cd a ernFxmlidd charintl'
I
M
' M is ),�nemtd by ch—md aisle ak,m ritc(uin:menh, r.•hkh ar. tvpiratlr t f 04- I
—k—ulherwise �edf d m tm. menuel.
Area can be expressed as:
A=By+My2
Hydraulic Radius, R can be expressed as:
R - A
P
where P is:
P=B+2y(i+M2)u
I-W the throe eyuatkaal abinv� thm wnahlm hair flr• faUclwitt(t wwa m-p (Alru.rdvr to
Fiputr 9.1):
A C1+:w.w 0 •rwi — of thou (ey h)
a - ftl num width dd the darnel ttq
M . %1. .10" t**.UI MIrIX06h4/ft ewticd) (JRw.WWAt!r lMnml
nlrrA,W.V,ixaw bd
P wuatalt petitneba (tq
R I Igdraultc ra;r— IM
y D"Oh of rlurr #0
All variables are known in Matu ing's Equation except y (found in AR°b7 term)
Rearranging Manning's Equation
AR'("
I =QMn 1(I.491',Sus)=(B"Y +M'y')" l(B':: +M*Y)/(B+2': (I+M2)5)16' Qs(cfs)= 11.19 Qm)(cfsl= 13.I4
l Longitudinal Slope= 0.0075 Longitudinal Slope= 0.0075
IManning's n = 0.035 Manning's n = 0.035
IL ARua= 3.04 AR "= 3.56
ARHi7 B y MA A
25-Year 0.00 0.992 5.00 4.92
I(N)-Year 0.00 1.052 5.00 5.53
Calculated Depth of Flow (A) = 0.99
Average Swale Depth (h) = 2.0 Olt, Swale meets design capacity
N:\20050\Dsgn\Stormwater\20050 25-yr NHC Swale Calc.xlsx Page 2 of 2

I
I
COlseni'urk-Phase 1
Thomas & Hutton Engineering Co.
Design Stable Swales and Diversions
'."0 NHC Calculations - Grasped S%Nala Dea
Swale A
Determine 25-Year and 100-Year Flow ror Channel
Use Rational Method for 25-Year Flow:
Flow: Q = CIA
Where: Q = Design Flow (efs)
C = Runuff Coefficient
1= 25-Year Rainfall Intensity
Area Description
Table 40-1
Runoff
Coefficient. C
Area
(act
Impervious
0.95
0.95
Lawn, Flat, Sandy
0.1
2.53
Composite Runoff Coefficient. C = 0.33
Time of Concentration
Use Tc =
5.00 min
t_s (in / In) =
10.70
Design Flow
C =
0.33
I, =
10.70
A =
3.48 acre
Qn =
12.36 crs
Estimate Channel Size
Estimated Channel Area, A W) =
3.53
Guesses for Actual Channel
Area:
Sideslope. M:I =
7
Channel Depth, d =
3
Bottom Width, B (ft) =
0
Actual Area (fi'-) =
63.00 OK
Hydraulic Radius, R (fi) =
1.48
Determine Manning's n value:
Job: 2(N)50
Date: 2/ 1712L)09
Deigned by: CAM
Checked B%: )DR
(See'fable 40-I, pg. 40-3 in NIK' Sronnw:uer Manual)
6, (in / hr) = 12.56
C = 0.33
1„„, = 12.56
A = 3.48 acre
()tw = 14.51 ers
Retardance Class (Table 60-4) =
D
Retardance Class to Use with Graph on Page 60-5 NHC Manual =
E
Pennissable Velocity (Ft/s) =
3.5 From Table 60-1
Hydraulic Radius (ft) =
1.48
V * R (For Use on Graph on Page 60-5 =
5.20
Manning s n Value from Graph on Page 60-5 =
0.035
N:\20050\Dsgn\Stormwater\20050 25-yr NHC Swale Calc.xlsx
Page 1 of 2

Olsen Park - Phase i
Job:
20050
TThomas R Hutton Engineering Co.
Date:
2/1 7/2009
Design Stable Swales and Di+ersions
Designed by:
CAM
NHC CalCtllati011S - Cray,ed S,a;de De>ign
Checked Bt:
JDR
Swale A
Determine Death of Flow in Seale
Max Velocity can be determined front Manning's Equation:
However, area and hydraulic radius are not known
r11w 11i mmirkC Lquati Kl ram L+e NI.1taK1 aM:
%Vhero C TLvk di -harm? tv ti—fw=nnrl t.f-)
a - 4lannang r.n+);lnx++5 +uefflcte+vl galinnnt+hn+l++nY
A i':r+rPN Cwflal aria of (k)rr fit (4), kho area tlu+mialk wt1h41 (Ir+w
taus Plmr "'t, Wjr wY
- R - Hydraulic r.Amm (4F. fawnd by drt Idutg ee xa.rrcWinal arra,. A
(WI (t), In wetted I:wrrtmetrr, P ((i) ft:< MOIL-(
ti - L,mgitudirm; sk-p:e tl thr La—rt .x( thr rhnnnrl aft faar'ft run).
Flgum $4
Diapam cef a [mpamoidel rltamxt`
M
♦ B
M t+ gr,venftd Fy ehant+el Adr !:l.F1 9F111rin!me1LCA whkh art typi—Ily VI (M-:3)
Irnk.re ruh— r -g—fi++11 m this manual.
Area can be expressed as:
A=By+My2
Hydraulic Radius, R can be expressed as:
P
where P is:
P.B+zy{1 +MY's
For dw Illeot agttatlam a6wv, thu vmLA a huvw thr Hdlnwing ft s mtap (,ak.a "to, to
Figufr R.3):
.i * C,.ns.w:hlw1 ar u.d mNr- t,q in
a Roth— width+d the dwlnA th)
M - !N.Ir +lope rNk- to M1r1t.r11a1f R yaAlrotll G(efrnwiwd t?' dAwmf
+iiir iliry nvYuixaxiehl
r W"" lvliam "fit)
R I ly rmlw rmbm (m)
y - I)apth.i more 3(t)
All variables are known in Manning's Equation except y (found in AR H'7 term)
Rearranging Manning'a Equation
ARk7=Q.:n/(1.49:;:Saa)=(B::y+M:,:y2)"[(B'y+M"y)/(B+2 y(1+M2).$))",,t
Qs (crs)= 12.36 Qua, (cfs)= 1.1.51
longitudinal Slope= 0.005 Longitudinal Slope= 0.005
Manning's n = 0.035 Manning's it = 0.035
AR'w7= 4.11 AR'-'= 4.82
AR 1/.7 B y M: l A
25-Year 0.00 0.976 7.00 6.67
100-Year 0.00 1.037 7D0 7.52
Calculated Depth of Flow (rt) = 0.98
Average Swale Depth (fl) 2.0 Ok, Swale [meets designcapacily
IN:\20050\Dsgn\Stormwater\20050 25-yr NHC Swale Calc.xlsx Page 2 of 2

Olsen Park - Phase 1 Job: 2tx)50
�} Thomas & Hutton Engineering Co. Date: 2i17/2009
Design Stable Swales and Diversions Designed by: CAM
4W—O° NHC Calculations - (sassed S%%ale Design Checked BY: JDR
Swale B
Determine 25-Year and 100-fear Flow for Channel
l'se Rational Method for 25-Year Flow:
Flow: Q = CIA
Where: Q = Design Flow (efs)
C = Runoff Coefficient
I =_5-Year Rainfall Intensity
Area Description
Table 40-1
Runoff
Coefficient. C
Area
(ac)
Impervious
0.95
0.10
Lawn, Flat, Sandy
0.1
0.25
Composite Runoff Coefficient, C = 0.34
Time of Concentration
Use Te =
5.00 min
I„ (in / hr) =
10.70
Design Flow
C =
0.34
I,, =
10.70
A =
035 acre
QZc =
1.25 cfs
iSee'rable 40-1. pg. 40 3 in \liC Swrnncater Manuall
1„s, (in / hr) = 12.56
C = 0.34
11,„, = 12.56
A = 0.35 acre
Q100 = 1.51 cfs
t Estimate Channel Size
I
FstimarM Chnnnrl Alta. A (ft) = 0.37
Guesses for Actual Channel Area:
Sideslope. M:I = 9
I Channel Depth, d = 3
Bottom Width. B (f) = 0
Actual Area W) = 81.00 OK
Hydraulic Radius, R (ft) = 1.49
Determine Mannin¢'s n value:
Retardance Class (Table 60-4) =
D
Retardance Class to Use with Graph on Page 60-5 NHC Manual =
E
Permissable Velocity (ft/s) =
3.5 From Table 60-1
Hydraulic Radius (ft) =
1.49
V ' R (For Use on Graph on Page 60-5 =
t
5.22
Manning's n value from Graph on Page 60-5 =
0.035
1 _ N:\20050\Dsgn\Stormwater\20050 25-yr NHC Swale Calc.xlsx Page 1 of 2

Olsen Park - Phase 1 Job: 20050
T 4 Thomas & Hutton Engineering Co. Date: 2I17/2t109
Design Stable Svvales and Diversions Designed by: CAM
t�'*�ra•`6` NHC Calculations -Grassed Swale, Design Checked B>: JDR
Swale B
Determine Depth of Flow in Sale
Max Velocitv can be determined from Manning's Equation
However, area and hydraulic radius are not known
li:c AL.Gnnht(; Cyw.:tirr:
car t4:.httaW a+:
1:OFA
U -
n .t
tVh—: Q
I'vak di.chdrgt- tv Bw rt"m m-1 (ds)
e
(dlme'*k+aletn)
.A
M— (.,q fl), the area tlhr�rtt wtwh flaw
lat.ss p1a:L due Ivl m+)
R -
r tl d—ile .d)— (Ydp. (wand hw dreldmg cr--s—lumal area.. A
ls�4 (1), by wetted 4x-Nmeter, P (A) fax' h'+•w!1
5 -
tAingitudiml slope of the invert of the channel 4ft Call/it run).
Flgptra"
Diagra— of a tnp-4dal ehanncl'
M
t' 'r
• B b
' M n gavertxvi Fry channel' .ide stripe teetuitxmvnaR whiai� am h•pically i:! (1d-})
u'k—mhcmaer -r- 4h d m tw. es.m I.
Area can be expressed as:
A=By+Myz
Hydraulic Radius, R can be expressed as:
R A
P
where P is:
P = R + 2t,/ 0 + AV)a-s
Far Ow Ihrm wplatlwa: etw my the vaNablta hive the kAN -1ng m.wdn p. (alsp r dw to
t•igure 3. t);
h - cY.rc--ki -rul — rd fl— 4:q (t)
H - Mn— wWmh:d the+amO#6
M • Na. dapu m*. In huHrantal/p vwWAll ty dh .ef
.idrsr'Wmpn'mmmrst
r WMltd jwriftwsw (11)
R I t),dr ubc mdlua ((t)
r - Depth of flow Oft)
All variables are known in Manning's Equation except y (found in ARm'7 teen)
Rearranging Manning's Equation
AR"r,' = Q"`n / (1.d9''Sn `) = (B' y + M*y') " I(B*y + M'y') / (B +2`: y(I+M-)'s)I (R'
Q-(cfs)= 1.28 Qlai(cfs)= 1.51
Longitudinal Slope= 0.018 Longitudinal Slope= 0.018
Manning's n = 0.035 Manning's n = 0.035
AR "= 0.22 AR'= 0.26
AR'`"'r B y M:l A
M-Year 0.00 0.296 9.00 0.79
100-Yem 0.0O 0.315 9.00 0.89
Calculated Depth of Plow (ft) = 0.30
Average Swale Depth (f0 = 2.0 Ok, Swale meets Resign capacity
I
N:\20050\Dsgn\Stormwater\20050 25-yr NHC Swale Calc.xlsx Page 2 of 2

I
Olsen Park- Phase l
Thomas & Hutton Engineering Co.
Design Stable Sx%ales and Diversions
w,. ® NHC Calculations - Gras,ed St+ale ❑
Swale C
}1 Determine 25-Year and 100-Year Floe for Channel
Use Rational Method for 25-Year Flow:
Flow: Q = CIA
Where: Q = Design Flow (cfs)
C = Runoff Coefficient
I = 25-Year Rainfall Intensity
Area Description
Table40-1
Runoff
Coefficient.0
Area
(ac)
Impervious
0.95
127
Lawn, Flat, Sandy
0.1
0.28
t
Composite Runoff Coefficient, C = 0.80
l
Time of Concentration
Use Tc = 5.00 min
I
I,s (in / hr) = 10.70
Design Flow
C = 0.80
6s = 10.70
A = 1.55 acre
Qa = 13.21 efs
Estimate Channel Size
Estimated Channel Area, A (ft) =
.1.77
Guesses for Actual Channel
Area:
Sideslope, M:1 =
15
Channel Depth, d =
3
Bottom Width, B (ft) =
0
Actual Area (ft-) =
135.00 OK
Hydraulic Radius, R (ft) =
1.50
Determine Mannina's n value:
Job: 20050
Date: 1_/1712(X)9
Designed by: CAM
Checked Bv: JDR
tSee'rable 40-1. pg. 40-3 in N'H(' titurmwater Manual)
h,,, (in / hr) = 12.56
C = 0.80
= 12.56
A = 1.55 acre
Qtus = 15.51 efs
Retardance Class (Table 60-4) =
D
Retardance Class to Use with Graph on Page 60-5 NHC Manual =
E
Pennissable Velocity (ftls) =
3.5 From Table 60-1
Hydraulic Radius (f) =
1.50
V i R (For Use on Graph on Page 60-5 =
5.24
Manning's It value from Graph on Page 60-5 =
0.036
IN:\20050\Dsgn\Stormwater\20050 25-yr NHC Swale Calc.xlsx Page 1 of 2

r
r
Olsen Park - Phase ti ~�
?t Thomas & Huttan Engineering Co.
Design Stable Swales and Diversions
n : r NHC Calculations - Gra:scd Se nle D
Swale C
Determine Death of Flow in Swale
Max Velocity can be determined from Manning's Equation:
However, area and hydraulic radius are not known
"llrr ATa�trthrF !"ryuatiral ran Lau >Mtrd ay:
1.92At➢
Q - q .+ Fc ..
Where! Q Kruk diwharge h• t w rharml (rfsj
n + ivtanndn� rawrµhtt�.i e.. 01de„1 (dia+era h'hkew)
.'I area Ilf %kW t^q tl), th.- area th' .Ujeth whirtl fl.nv
1ai t latac� Fc:e A haul
it 11?drau§ic —M— Wq (—.,d by dretdrng.Ta,cr.t I-nal arra, A
It.) (1). by xret" perimutae' P (n) I:-tvf�ru�f
9 U,m&riwdiml A,,pe t f thr —I nF the rhaa,nel fit In111tt mra.
0
�+1
rbsr "
T.li.jp— trf a Crnlwaaidnl rh unrerP
• M ur ttr'renxd by clmnrte!:+ide eta.pr ngairrmrnAr, wtdrir nre tvpitailr s-i {M+31
auk^++ Murerwv r .yecaFnwl en. thrs rnanuat.
Area can be expressed as:
A=By+Myz
Hydraulic Radius, R can be expressed as:
R A
P
where P is:
P-B+2y(1+W)as
Fur dw ihrrw agwannne jbmvw ttw rarnblml have du+ Wla wLng maartmp ialw mdla t&
Mirurr ] 3t:
:S r Cs.ew-artli—I arw.d fI.W 4.q nl
a - nnro m 'AtIt ar the whan-I (it)
M 1t4V'4"rr nrih+ 01 horiera10111t"O qh rll hlf—eutnt Jr rfwnnd
+ik dc*r rrgn+..e ceuhl
P weel.+d I-VUFret r 00
It Hydraulic rA&M IBC)
y - IX"k'4 lletr lfl)
All variables are known in Manning's Equation except y (found in AR ("'' term)
Rearranging Manning's Equation
AR17 = Q*n / (1.49-S° 5) _ (B-y + M'''y') '" I(B,::y + Mr'v2) / (B + 2"y(I+M2)'`)] M7
Qn (cfs)= 13.21 QI'.. (cfs)` 15.51
Longitudinal Slope= 0.011 Longitudinal Slope= 0.011
Manning's n = 0.036 Manning's n = 0.036
AR W7= 3.04 AR '= 3.57
AR' B y MA A
25-Year 0.00 0.654 15.00 6.41
IM-Year 0.00 0.695 15.00 7.24
Calculated Depth of flow (f1) = 0.65
Average Swale Depth (ft-) = 2.0 (1k, Swale meets design capacity
Job: 2W50
Date: 2/1 7C009
Designed hy: CAM
Checked Bv: 1DR
N:\20050\Dsgn\Stormwater\20050 25-yr NHC Swale Calc.xlsx
Page 2 of 2

Olsen Park Phase 1
Job:
20050
a -
f T g Thomas & Hutton Engineering Co.
Date:
2/17/'_(x)9
Design Stable Scales and Diversions
Designed by:
CAM
~PE�M6 NHC Calculations - (raked Smale Resign
Checked By:
JDR
Swale D
Determine 25-Year and 100-Year Flow for Channel
C'sc Rational Method for 25-Year Flow:
Flow: Q = CIA
Where: Q = Design Flow (efs)
C = Runoff Coefficient
iSee'rable -N-I. p;_. 40. + in Nli(' Stomxsater Manual)
1= 25-Year Rainfall•Intensity
`j
Area Description
Table40-1
Runoff
Coefficient,C
Area
(ac)
Impervious
0.95
1.27
Lawn, Flat, Sandy
0.1
0.28
fComposite Runoff Coefficient. C =
lTime
0.80
or Concentration
Use Tc = 5.00 min
1„ (in / br) = 10.70
1„s, (in / hr) =
12.56
Desi ng Flow
f C = 0.80
C =
0.80
1,5 = 10.70
IIINI =
12.56
1 A = 1.55 acre
A =
1.55 acre
Q, = 13.21 efs
Q100 =
15.51 cis
Estimate Chanel Size
Il Estimated Channel .Area, A (ft') = 3.77
Guesses for Actual Channel Area:
Sideslope, M:I = 15
Channel Depth. d = 3
Bottom Width. B (ft) = 0
i Actual Area (ft) = 135.00 OK
IHydraulic Radius, R (ft) = 1.50
Determine Mannine's n value:
i
1 Retardance Class (Table 60-4) =
D
RetardanLe Class to Use with Graph on Page 60-5 NHC Manual =
E
Petmissable Velocity (ft/s) =
3.5 From Table 60-1
Hydraulic Radius (ft) =
1.50
V < R (For Use on Graph on Page 60-5 =
5.24
Mannings n value from Graph on Page 60-5 =
0.035
L N:\20050\Dsgn\Stormwater\20050 25-yr NHC Swale Calc.xlsx Page I of 2

. Olsen Park - Phase I Job: 20050
Thomas R Hutton Engineering Co. Date: 2/17/2009
'm �o Design Stable Swales and Dig ersions Designed by: CAM
yi-ietMa_ NHC Calculations - Grassed Swale Design Checked By JDR
Swale D
Determine Depth of Flow in Swale
Max Velocity can be detennined from Manning;s Equation:
However. area and hydraulic radius are not known
i Me Rfa-rninK ""'Ition can It M.t.4
1. 1S9
LE n A A,.. -4..t
lti7rrrn� L a Peek alirhacgr. h+ihe channel ttf.)
' + M1lannfr,rK nr.rg9uwe,:<caturfitienl Ntitnetaclan�! tos?
.A . tycw w t srkA ar" of lures tM flj, ilk. at- Ilm me erltirh flow
Iakcai plxe lag, l d"'I
k + Fly -dic radius (ftj, 1,m d bw dwtdrn q cocas ft—d are:. A
Isxt Et). by wctled prnmetea. Y rh1 ft- ttt':nt;l
5 - "In Sifrm-Inml+lops• rd thr i—I td the channel Ifl lall,•'/t mu).
Hn,ate fd
f)Esipram cd a t-pnraidal elki—l-
i ,
i
M
rI-,- .
r l
M
♦ B
I M is prwenxd by clrurrrrl aide elope-pirert taN- which ere typicdly.i:1 Ilif-i)
un1m. ollrcrwiee mpr. �iatel m tMa rnenua7.
Area can be expressed as:
A=By+Myz
I Hydraulic Radius, R can be expressed as:
R_ A
P
where P is:
P=B+2y(1+Ag)IRs
Fa 11ra Ibrw• 9"Akear abww the Vartoblw hates Itrr fsllawln& n, Inp (aho NAur to
Flga- 3-1):
A [Sc„r_w,tluet.l nna tdEluw hrl hl
a - pnthmr wadi, a the channel Ihj
M - SIi1rAgw relk+(tl lwriemkAUaby,Meerf
,utr,roperalui .Ix +)
P • NtxtMd p+rk"OkV Jh)
R e lildrardtt redrrr t1t)
Y - Or ptlt of now lrt)
All variables are known in Mannines Equation except y (found in AR"' term)
Rearranging Mannines Equation
AR.rs, = Q:tn / ( 1.49*Si, s) _ (B-y + M-y') ¢: [(B„,y + Miy'-) / (B + 2.;•y(1+M2).;)l .'A'
Q29 (cfs)= 13.21 Q,,,,, (cfs)= 15.51
Longitudinal Slope= 0.011 Longituclinal Slope= 0.011
Manning's n = 0.035 Manning's it = 0.035
AR'`s'= 2.96 AR17= 3.47
AR' B y M:1 A
25-Year 0.00 0.647 15.00 6.29
100-Year 0.(X) 0.687 15.00 7.08
Calculated Depth of Flow (ft) = 0.65
Average Swale Depth (ft) = 2.0 Ok, Swale meets design capacity
L
LN:\20050\Dsgn\Stormwater\20050 25-yr NHC Swale Calc.xlsx Page 2 of 2

I
I
Olsen Park - Phase 1 Job: 20050
TThomas & Hutton Engineering Co. Date: 2/17/2009
HDesign Stable Swales and Di%ersions Designed by: CAM
~PFN,YL NHC Calculations - Glassed Swale Design _ _ _ Checked By: JDR
Swale E
Determine 25-Year and 100•Year Flow ror Channel
Use Rational Method for 25-Year Flow:
f Flow: Q = CIA
1 Where: Q = Design Flow (eLU
i C = Runoff Coefficient
I = 25-Year Rainfall Intensity
L
Area Description
Table 40-1
Runoff
Coefficient. C
Area
(ac)
Impervious
0.95
0.10
Lawn, Flat, Sandy
0.1
0.25
Composite Runoff Coefficient, C = 0.34
Time of Concentration
Use Te =
5.00 min
Is (in / hr) =
10.70
Design Flow
C =
0.34
I,s=
10.70
A =
0.35 acre
Qzs =
1.25 efs
Estimate Channel Size
Estimated Channel Area. A W) =
0.37
Guesses for Actual Channel
Area:
Sideslope, MA =
9
Channel Depth, d =
3
Bottom Width, B Oil =
0
Actual Area Ot) =
81.00 OK
Hydraulic Radios. R (ft) =
1.49
Determine Manning's n value:
!Sce fable 40-1. pg. 40-3 in \IIC Stormw,uer Manual)
h,�, (in / hr) = 12.56
C = 0.34
12.56
A = 0.35 acre
Qtm = 151 cis
Retatdance Class (Table 60-4) =
D
Retardance Class to Use with Graph on Page 60-5 NHC Manual =
E
Petmissable Velocity (ft/s) =
3.5 From Table 60-1
Hydraulic Radius (ft) =
1.49
V * R (For Use on Graph on Page 60-5 =
5.22
Manning's n value from Graph on Page 60-5 =
0.035
IN:\20050\Dsgn\Stormwater\20050 25-yr NHC Swale Calc.xlsx Page 1 of 2

Olsen Park - Phaw 1
Job:
NO50
si
Thomas de Hutton Engineering Co.
Date:
2/17f--O(19
Design Stable SA ales and Ditersions
Designed by:
CAM
M`Fat�o�
NHC Calculations - Gtase•dSwaleDosigi
Checked Br:
JDR
Swale E
Determine Depth or Flow in Swale
Max Velocity can be detennined from Manning's Equation
However, area and hydraulic radius are not known
Thu ita-ring Utuatlltt v" tR' -tnt%-d d":
:1 Ro..a it
When•• Q +.
I'vak ft nw' eFrennel I+#+)
n
DAxnn".ntt ruualrrAws lz,elilclr!nl idinn,lv+l.•n[x.: )
eI
[ 54-rrrl llltllil 190A U/ ROW ftiI II), IN Arai Wd-Uf.th %'IWW l tllw
take plat'a•1.rr hetuml
R
I lydr: W radius (ftl. t sated by dtxldinp crceo-rrr•Is nal area, A
(sq fI.1, b, wetWd pr,imelrn, P(Ny Is-ddam8
5 -
L r i;itwdim!.A.p. Ld the i—t nt the h—.i ;ft talc/ft r").
1 Iw4� ul
Dtaipem of a trap—ddnl otau —l'
1� 70 i~
1
t a
L
M it pt-m,.d by cllanttel aide slope —runt —1% t hit h are wpindly VI 414-11
unlr•+x other.ree epe hed en tMr manual.
Area can be expressed as:
A--By+Myl
Hydraulic Radius, R can he expressed as:
R `/
P
where P is:
P=B+2y(I +M2)p.e
Far th- paw agtwwm ob~. the var wbko Iwva dw fe, li ing au Inp (also Ww W
r-igury 3JI:
A r:tn.w.aMI—I — L.f flow tlq ftl
A NIUM WNIth td the cIUM d (fl)
j A4 - Sideihvv ralh, 90- hwirtmwNa%A.Wrali Wrhva jlY.AunnA
I .idr,dt*s rnA,emwxata!
P - w.tivd 1*~Ift (1t)
R + Ifydr—Ik radius Ift)
y - Llryih d tkwr #0
I All variables are known in Manning's Equation except y (found in AR U'7 term)
Rearranging Manning's Equation
ARe''=Q`n/(1.49^Sns)=(B*y+W:y') ((B^'y+M°y)/(B+2*y(1+M+-)`)]t
Q_.,(cfs)= 1.28 Qu.,(cfs)= 1.51
IAngittldinal Slope= 0.018 Longitudinal Slope= 0.018
IManning's n = 0.035 Manning's n = 0.035
AR` 7= 0.22 AR+"= 0.26
ARr,; B y M:I A
25-Year 0.00 0.296 9.00 0.79
IOO-Year 0.00 0.315 9.00 0.89
Calculated Depth of Flaw (fu = 0.30
Average Swale Depth (ft) = 2.0 Ok, Swale meets design capacity
IN:\20050\Dsgn\Stormwater\20050 25-yr NHC Swale Calc.xlsx Page 2 of 2

Olsen Park- Phase I Job: 2(X)50
T llxmlas & Hutton Engineering Co. Date: 2/17/2001)
Design Stable Swales and Di%ersions Designed by: CAM
NHC Calculations - Grnswd Swale resin C hecl:ed By: JDR
Swale F
Determine 25.Year anti 100-Year Flow for Channel
Use Rational Method for'-5-Year Flow:
Flow: Q = CIA
Where: Q = Design Flow (cfs)
C = Runoff Coefficient
1= 25-Year Rainfall Intensity
Area Description
Table 40-1
Runoff
Coefficient. C
Area
(ac)
Impervious
0.95
0.00
Lawn, Flat. Sandy
0.1
1.89
4 Composite Runoff Coefficient. C = 0.10
Time of Concentration
Use Tc =
5.00 min
J_5 (in / hr) =
10.70
Design Flow
C=
0.10
In =
10.70
A =
1.89 acre
Qaa =
2.02 cfs
(sec Table 40-1, pg..10-3 in NHC Stonmvate( \9a1nial)
I,,,, (in / hr) = 12.56
C = 0.10
1,,,, = 12.56
A = 1.89 acre
Q„a = 2.37 cfs
f Estimate Channel Size
i
Estimated Channel Aron, A (ft) = 0.59
j Guesses for Actual Channel Area:
Sideslope, MA = 5
I{
Channel Depth, d = 3
Bottom Width. B (ft) = 0
Actual Area (ft) = 45.00 OK
i
Hydraulic Radius. R (ft) = 1.47
Determine Mannine's n value:
Retardance Class (Table 60-4) =
D
Retardance Class to Use with Graph on Page 60-5 NHC Manual =
E
Pennissable Velocity (ft/s) =
3.5 From Table 60-1
Hydraulic Radius (f) =
1.47
V * R (For Use on Graph on Page 60-5 =
5.15
Mannines n value from Graph on Page 60-5 =
I`
0.0-35
N:\20050\Dsgn\Stormwater\20050 25-yr NHC Swale Calc.xlsx Page 1 of 2

.� Olsen Park - Phase 1
Job:
20050
�' Thomas & Hutton Engineering Co.
Date:
2l17i_200t)
;,
O484H+iO
Design Stable Swales and Diversions
Designed by:
CAM
NHC Calculations - Gras..ed Swale Design
Checked By:
JDR
Swale F
r
{ Determine Depth of Flow in Swale
[ Max Velocity can be detennined from .,OanninE s Equation:
However. area and hydraulic radius are not Mown
{
I '13u> Atamning lquIti•rer caar be nhtWd a :
i J 92Y9
- n A Rc«: y:
447+ern: LJix-ha.-Kr hrtM•cksannrl lsf•)
j Atannmg muglrm., .'ef4cienl (dim.m. h niwor)
A e:arcr;t...-rtyr,r>al urea of M.w tsq ft). Nre 4roa IlinY jth which Fla
IaG:a plrwo (Vf Ir1.ceJ
R +• I I u]tc rsdsu+ khl, found by d­tdriy5 arcs, A
taq fill. by wet" perimelee. P(o) Nt hIt—I
S - f or stitudiml Aope L+f the to Yrt d the rhannet {k fait_eft run).
F1tram 34
Diagmm of a trapenddul rhartner
9d W
IN
r
'M
Ir I
M
i�
' M as 1; rvenaed by channel ride etnpe ra+gair<measn. +ehich arc txptetlly 3A (M-t)
i oink.. oMerwisc +pratilend m Ilue rnenwl.
Area can be expressed as:
A=By+Myl
Hydraulic Radius, R can be expressed as:
R A
P
where P is:
{ P=B+2y(1+11V)es
jl Fur the i1hro equonnrr obmv, tha vaw4kca havv rM tntk Wnp• moamayr (alm wlwW
I•igure 341:
.h d fin+. t.«'f NI
ll - 6nthim width td the hwm l iftj
M - °Nda rintsr rr'W+tell hurie.vd lft vordeW) 4lnrtvrrn.+rd by rfl-11l
r�dr+(<pe ngur warwrxl
r WMted wrirrwhatrf)
R • I lydraue radrux tft)
y - ihput of 11— (ff)
All variables are known in Mannines Equation except y (found in AR'6('7 term)
Reatranging Manning's Equation
AR '-'= Q"n / (1.49. S15) = (B*y + M*y'-) * I(B*y + M^`y'-) / ( B + 2'y(I+M2) c)] .rtv
lQ,s (cfs)= 2.02 Q„ri (cfs)= 2.37
i
Longitudinal Slope= 0.008 Ungitudinal Slope= 0.008
Manning's n = 0.035 Manning's n = 0.035
AR"6'= 0.53 AR "= 0.62
AR' B y M:I A
25-year 0.00 0.515 5.00 1.33
100-year M 0.00 0.546 5.00 1.49
Calculated Depth of Flow (ft) = 0.52
Average Swale Depth (fl) = 2.0 Ok+ Swale meets design capacity
L
N:\20050\Dsgn\Stormwater\20050 25-yr NHC Swale Calc.xlsx Page 2 of 2

Olsen Park - Phase I
'r} Thomas & Huuon Engineering Co.
Design Stable Swales and Diversions
:a, ® NHC Calculations - Grassed S xale 1]
Swale G
Determine 25-fear awl 100-Year Flow for Channel
Use Rational Method for 25-Year Flow:
Flow: Q = CIA
Where: Q = Design Flaw (cfs)
C = Runoff Coefficient
1= 25-Year Rainfall Intensity
I
Ij
Area Description
Tabled0-1
Runoff
Coefficient.0
Area
(ae)
Impervious
0.95
0.10
Lawn, Flat. Sandy
0.1
2.20
Composite Runoff Coefficient, C = 0.14
Time of Concentration
Use Te =
r
5.00 min
1;, (in / hr) =
10.70
Desigii Flow
C =
0.14
1„ =
10.70
A =
2.30 acre
Qss =
3.37 cts
Estimate Channel Size
Estimated Channel Area, .A (ft) =
096
Guesses for Actual Channel
Area:
Sideslope, M:I =
10
Channel Depth, d =
3
Bottom Width, B (ft) =
0
Actual Area (ft) =
90.00 OK
Hydraulic Radius. R (ft) =
1.49
Determine Manna's n value:
jab: 20050
Date: 211712009
Designed hy: CAM
Checked Bt: JDR
(tire "ruble all -I. pg. 40-3 in NHC Stamm ater Manual)
1„ r, (in / hr) = 12.56
C = 0.14
h,,, = 12.56
A = 2.30 acre
Q100= .1.% efs
Retardance Class (Table 60-4) =
D
Retardance Class to Use with Graph on Page 60-5 NHC Manual =
E
Permissable Velocity (ft/s)=
3.5 From Table 60-1
Hydraulic Radius (ft) =
1.49
V ' R (For Use on Graph on Page 60-5 =
5.22
Manning's n value from Graph on Page 60-5 =
0.035
I
IN:\20050\Dsgn\Stormwater\20050 25-yr NHC Swale Calc.xlsx Page 1 of 2

Olsen Park- Phase 1
Job:
_'005O
T
Thomas & Hutton Engineering Co.
Dace:
2/17/2009
�o
H
Design Stable Seale. and Diversions
De+igned b):
CAM
NHC CalCUIaIi0uS - (irased Scale Design
Chteked B):
JDR
Swale G
Determine Depth of Flow in Swale
%lax Velocity can be derennined from Manning's Equation:
` However, area and hydraulic radius are not known
I '"m Manning Gqun[km t �i ti- aIabmd aa.
!.•fB9
I 1ti'hcn: f2 a Mmk di-rh.%X na Ow rhvnm•I (cos)
Mar— mughrr,: s, c..rrtkfam (ditnum4onk—)
A ; [. W--..119urral tt. a uE flaw ( 7 ft), tb" area Mtn+ Ah whirb flew
latu� plan r.t A W-)
Ft I1}'draull —&— (fej,f"nd by dwndmgcrnaa-%err-na sm., A
(sq ft) • by warted P-imat—. P (,ft) I.— knhwv)
S — Wng(twdtmt ale pe eat the ttavmt t4 the rtmnnef fit faa/fY run).
FYgars #-3
1?lagram aS a troPc�aadnl rhannet'
r
'00r0- -i 1
M
V
1 11,
`M iv g:-. --d by rha rvd.ide -&,pr rcgair rAn. whicfi arc [T'P:ra71y' l=7 ;Af—;t)
unIm5 nlhL--w-p,xihed m tMs rn mLW.
Area can be expressed as:
A = By -(1- My2
Hydraulic Radius, R can be expressed as:
R A
P
where P is:
I P=B+2Y(I +Af)"
II F s t1w Ihnw equatk a shavxr, Ow vambbs ho v tha foa rWing tnwn[ngy (alcn raw to
Figure 3 }):
A Cy�VWW may fflwv Isy by
g L AU= watch' i thr Omiruwf Ito
h1 • tilaly wlgae ntgu qtt hut4aatlxi/It +vvHr�ftemari+wJfyr,itaaaA
-W 41M rljlnfiraa w
P • iai.4k J p t*m#W* (ft)
R Nxvlrapic radius (R)
v "t"h of paw• 00
All variables are known in Manning's Equation except y (found in AR term)
Reafranging Manning's Equation
AR" =Qan/(I.a9-S'ts)=(B':y+M'y') IfB:::y+M'y2)/(B+2`1y(I+M'1'S)].rat
Q2., W )= 3.37 Q,a, (cfs)= 3.96
Longitudinal Slope= 0.01 Longitudinal Slope= 0.01
Manning'% n = 0.035 Manning's n = 0.035
AR'"''_ 0.79 AR"= 0.93
ARIv7 B y M:I A
25-Year (1.00 0.460 10.00 2.11
100-Year M0.00 0.489 10A) 2.39
Calculated Depth of Flow (h) = 0.46
Average Swale Depth (ft) = 2.0 Ok, Swale meets design capacity
LN:\20050\Dsgn\Stormwater\20050 25-yr NHC Swale Calc.xlsx Page 2 of 2

I
I. -
I

Olsen Park - Phase 1 Job: 20050.404
Thomas & Hutton Engineering Co. Date: 12/4/08
rStorm Drain Design Considerations Revised:
ICPR Results: 25-Year Flowrate and 25-Year Velocity (NHC) By: CAM/JDR
User Input Data
Calculated Value
Reference Data
STORM #1 (RR-OSS #1)
The storm drain pipe was sized in ICPR version 3.1 to meet the requirements of the County and State as identified
previously in this report.
25-Year Flowrate:
The Link Min/Max report in Section 2.3: Post Development ICPR Model Input and Results indicates that the:
25-Year Flowrate = 10.37 cfs
25-Year Velocity:
The purpose for evaluating the 25-year design velocity is to determine the requirements for an energy dissipator to
protect downstream conveyance. This analysis assumes the maximum, permissible discharge velocity is 2.0 fps
(bare soil). Therefore, an energy dissipator shall be appropicately sized for velocities exceeding 2.0 fps.
The Link Time Series report in Section 2.3: Post Development ICPR Model Input and Results indicates that the:
25-Year Peak Discharge Velocity = 4.03 ft/s
Velocity = 4.03 fps > 2.0 fps (Permissible Velocity of Bare Soil)
Therefore, an energy dissipator IS required.
Calculate Energy Dissipater Parameters
Design Flow, Q = CIA 10.37 cfs
Pipe Diameter (d) = 24 in
Maximum Velocity, V = 4.03 fps
Zone of Apron:
2
(See Figure 50-14, pg. 50-25 in NHC Stormwater Manual)
Length of Apron (3*pipe dia.) :
6 ft
(See Figure 50-15, pg. 50-26 in NHC Stormwater Manual)
Width (3*pipe dia.):
6 ft
(See Figure 50-15, pg. 50-26 in NHC Stormwater Manual)
Minimum Stone Size:
6 in.
(See Figure 50-15, pg. 50-26 in NHC Stormwater Manual)
Depth of Rip -Rap:
18 in.
(See Figure 50-15, pg. 50-26 in NHC Stormwater Manual)
N:\20050\Dsgn\Stormwater\20050 Supporting -Pipe Calcs.xlsx

Olsen Park - Phase 1 Job: 20050
.r = Thomas & Hutton Engineering Co. Date: 11/3/2008
o New Hanover County - Section 50 -- Design of Energy Dissipater Designed By: CAM
Pipe System Design Procedure: Rip -Rap Outlets (NHC) Checked By: JDR
User Input Data
Calculated Value
Reference Data
` STORM #2
I Calculate Design Flow
Use Rational Method:
Design Storm: 25-Year
Drainage Area (A): 1.55 acre
Runoff Coefficient (C): 0.80
25-Year Intensity (1): 10.70 in/hr
Design Flow, Q2s = CIA 13.21 cfs
Contributing/Upstream, Q = 0 cfs
Total Required Flow, Q21= CIA 13.21 cfs
Calculate Design Velocity
I Formula: V = Q/A
Where: V = Maximum Velocity (fps)
Q = 25-Year Design Flow Rate (cfs)
A = Cross Sectional Area (sf)
Calculate Cross Sectional Area of Pipe
Pipe Diameter (d) = 24 in.
Cross Sectional Area, A = PI*(d^2)/4
A = 3.14 sf
Maximum Velocity, V = 4.21 fps
' Calculate Energy Dissipater Parameters
Design Flow, Q = CIA 13.21 cfs
I Pipe Diameter (d) = 24 in
1 Maximum Velocity, V = 4.21 fps
Description
C
Area (ac)
Lawns, sandy, avg.
0.1
1
0.28
Impervious
0.95
1.27
Composite Runoff Coefficient, C = 0.80
(See Table 40-I, pg 40-3 in NHC Stormwater Manual)
(Tc = 5 rains, Atlas 14 NOAA)
Zone of Apron:
1
(See Figure 50-14, pg. 50-25 in NHC Stormwater Manual)
Length of Apron (3*pipe dia.) :
6 ft
(See Figure 50-15, pg. 50-26 in NHC Stormwater Manual)
Width (3*pipe dia.):
6 ft
(See Figure 50-15, pg. 50-26 in NHC Stormwater Manual)
Minimum Stone Size:
3 in.
(See Figure 50-15, pg. 50-26 in NHC Stormwater Manual)
Depth of Rip -Rap:
12 in.
(See Figure 50-15, pg. 50-26 in NHC Stormwater Manual)

Olsen Park - Phase I Job: 20050
Thomas & Hutton Engineering Co. Date: 1 1/3/2008
New Hanover County - Section 50 -- Design of Energy Dissipater Designed By: CAM
O
Pipe System Design Procedure: Rip -Rap Outlets (NHC) Checked By: JDR
User Input Data
Calculated Value
Reference Data
I STORM #3
Calculate Design Flow
Use Rational Method:
Design Storm: 25-Year
Drainage Area (A): 1.55 acre
Runoff Coefficient (C): 0.80
t 25-Year Intensity (I): 10.70 in/hr
Design Flow, Q25 = CIA 13.21 cfs
Contributing/Upstream, Q = 0 cfs
Total Required Flow, Q25 = CIA 13.21 cfs
I Calculate Design Velocity
Formula: V = Q/A
Where: V = Maximum Velocity (fps)
Q = 25-Year Design Flow Rate (cfs)
A = Cross Sectional Area (st)
Calculate Cross Sectional Area of Pipe
I Pipe Diameter (d) = 24 in.
Cross Sectional Area, A = Pl*(dA2)/4
A= 3.14 sf
Maximum Velocity, V = 4.21 fps
Calculate Energy Dissipater Parameters
Design Flow, Q = CIA 13.21 cfs
Pipe Diameter (d) = 24 in
Maximum Velocity, V = 4.21 fps
Description
C
Area (ac)
Lawns, sandy, avg.
0.1
0.28
Impervious
0.95
1.27
Composite Runoff Coefficient, C = 0.80
(See Table 40-1, pg 40-3 in NHC Stormwater Manual)
(Tc = 5 mins, Atlas 14 NOAA)
Zone of Apron: 1 (See Figure 50-14, pg. 50-25 in NHC Stormwater Manual)
Length of Apron (3Ypipe dia.) : 6 ft (See Figure 50-15, pg. 50-26 in NHC Stormwater Manual)
Width (3*pipe dia.): 6 ft (See Figure 50-15, pg. 50-26 in NHC Stormwater Manual)
Minimum Stone Size: 3 in. (See Figure 50-15, pg. 50-26 in NHC Stormwater Manual)
Depth of Rip -Rap: 12 in. (See Figure 50-15, pg. 50-26 in NHC Stormwater Manual)

Olsen Park - Phase 1 Job: 20050.404
Thomas & Hutton Engineering Co. Date: 12/4/08
Storm Drain Design Considerations Revised:
I ICPR Results: 25-Year Flowrate and 25-Year Velocity (NHC) By: CAM/JDR
I user Input Data
II Calculated Value
t Reference Data
STORM #4 (RR-OSS #2)
The storm drain pipe was sized in ICPR version 3.1 to meet the requirements of the County and State as identified
previously in this report.
25-Year Flowrate:
The Link Min/Max report in Section 2.3: Post Development ICPR Model Input and Results indicates that the:
25-Year Flowrate = 9.22 cfs
25-Year Velocity:
The purpose for evaluating the 25-year design velocity is to determine the requirements for an energy dissipator to
protect downstream conveyance. This analysis assumes the maximum, permissible discharge velocity is 2.0 fps
(bare soil). Therefore, an energy dissipator shall be appropicately sized for velocities exceeding 2.0 fps.
The Link Time Series report in Section 2.3: Post Development ICPR Model Input and Results indicates that the:
25-Year Peak Discharge Velocity = 7.51 ft/s
Velocity = 7.51 fps >
Therefore, an energy dissipator IS
2.0 fps (Permissible Velocity of Bare Soil)
required.
Calculate Energy Dissipater Parameters
Design Flow, Q = CIA 9.22 cfs
Pipe Diameter (d) = 15 in
Maximum Velocity, V = 7.51 fps
Zone of Apron: 2 (See Figure 50-14, pg. 50-25 in NHC Stormwater Manual)
Length of Apron (3*pipe dia.) : 3.75 ft** (Sec Figure 50-15, pg. 50-26 in NHC Stormwater Manual)
Width (3*pipe dia.): 3.75 ft** (See Figure 50-15, pg. 50-26 in NHC Stormwater Manual)
Minimum Stone Size: 6 in. (See Figure 50-15, pg. 50-26 in NHC Stormwater Manual)
Depth of Rip -Rap: 18 in. (See Figure 50-15, pg. 50-20 in NHC Stormwatcr Manual)
** Minimum Length of Apron and Width shall be 5 feet.
N:\20050\Dsgn\St.ormwater\20050 Supporting -Pipe Calcs.xlsx

U.S. ARMY CORPS OF ENGINEERS
WILMINGTON DISTRICT
Action Id. SAW-2008-1284 County: New Hanover U.S.G.S. Quad: Scotts Hill
GENERAL
Property Owner:
Address:
Telephone No.:
(REGIONAL AND NATIONWIDE; VVRIrV CA'''ION
Size and location of property (water body, road name/number, town, etc.): The 89.37 acre tract is located off
Murravville Road, Wilminaton, New Hanover County, North Carolina Location: 34 2982°N 77 8670°W Parcel
#s R03400-002-003-001 & R03500-001-014-000. --
Description of projects area and activity: The proposal includes the placement of fill material into Section 404 waters
to facilitate access for a softball and park complex. There will be two impact areas as depicted on the attached
Plans for the construction of roads for the park. Impact Area #1 is authorized for 65 linear of permanent impact
for the installation of a road crossina and 10 linear feet of temporary impact for the installation of the retaininz
walls. Impact Area #2 is authorized for 84 linear of permanent impact for the installation of a road crossing and
10 linear feet of temporary impact for the installation of the retaining walls
Applicable Law: ® Section 404 (Clean Water Act, 33 USC 1344)
El Section I0 (Rivers and Harbors Act, 33 USC 403)
Authorization: Regional General Permit Number:
Nationwide Permit Number: 14
Your work is authorized by the above referenced permit provided it is accomplished in strict accordance with the attached
conditions and your submitted plans. Any violation of the attached conditions or deviation from your submitted plans may subject the
pemrittee to a stop work order, a restoration order and/or appropriate legal action.
This verification will remain valid until the expiration date identified below unless the nationwide authorization is modified,
suspended or revoked. If, prior to the expiration date identified below, the nationwide permit authorization is reissued and/or
modified, this verification will remain valid until the expiration date identified below, provided it complies with all requirements of
the modified nationwide permit. If the nationwide permit authorization expires or is suspended, revoked, or is modified, such that the
activity would no longer comply with the terms and conditions of the nationwide permit, activities which have commenced (i.e., are
under construction) or are under contract to commence in reliance upon the nationwide permit, will remain authorized provided the
activity is completed within twelve months of the date of the nationwide permit's expiration, modification or revocation, unless
discretionary authority has been exercised on a case -by -case basis to modify, suspend or revoke the authorization.
Activities subject to Section 404 (as indicated above) may also require an individual Section 401 Water Quality Certification. You
should contact the NC Division of Water Quality (telephone [phone]) to determine Section 401 requirements.
For activities occurring within the twenty coastal counties subject to regulation under the Coastal Area Management Act (CAMA),
prior to beginning work you must contact the N.C. Division of Coastal Management in Wilmington, NC, at [phone].
This Department of the Army verification does not relieve the pennitte of the responsibility to obtain any other required Federal,
State or local approvals/permits.
If there are any questions regthisrif ion, of the c ditfons of the Permit, or the Corps of Engineers regulatory
program, please contact Kir�ber76g
t 10 51 82 or ki �[e-mail].
Corps Regulatory Offigia�� \ / �Date: December 15, 2008
Expiration Date of V fi tia Dece 1512011
The Wilmington District is committed to providing the higliest level of s pport to the public. help us ensure we continue to do so,
please complete the attached customer Satisfaction Survey k visit htt :// saw.0 ace.army.iTdl7WETI,ANDShndex.htniI to
complete the survey online.
FEB 2 4 2009
BY:

Determination of Jurisdiction:
❑ Based on preliminary information, there appear to be waters of the US including wetlands within the above described project area.
This preliminary determination is not an appealable action under the Regulatory Program Administrative Appeal Process
( Reference 33 CFR Part 331).
❑ There are Navigable Waters of the United States within the above described project area subject to the permit requirements of
Section 10 of the Rivers and Harbors Act and Section 404 of the Clean Water Act. Unless there is a change in the law or our
published regulations, this determination may be relied upon for a period not to exceed five years from the date of this
notification.
❑ There are waters of the US and/or wetlands within the above described project area subject to the permit requirements of Section
404 of the Clean Water Act (CWA)(33 USC § 1344). Unless there is a change in the law or our published regulations, this
determination may be relied upon for a period not to exceed five years from the date of this notification.
® The jurisdictional areas within the above described project area have been identified under a previous action. Please reference
jurisdictional determinations issued 12/15/08. Action ID SAW-2008-1284.
Basis of Jurisdictional Determination:
Corps Regulatory
Date:
SURVEY PLATS, FIELD SKETCH, WETLAND DELINEA'I=i(�MS, PROJECT PLANS, ETC., MUST BE
ATTACHED TO THE FILE COPY OF THIS FORM, IF REQUIRED OR AVAILABLE.
Copy Furnished:
Chad Coburn, DENR-DWQ, Wilmington Regional Office, 127 Cardinal Drive Ext., Wilmington, NC 28405
Thomas King, Spangler Environmental, Inc., 224 Fayetteville Street, Suite 400, Raleigh, NC 27601

ACTION ID # SAW-2008-1284
SPECIAL CONDITIONS:
1. In order to compensate for impacts to 149 linear feet of stream impacts, the permittee shall make
payment to the North Carolina Ecosystem Enhancement Program (NC EEP) in the amount determined
by the NC EEP, sufficient to perform the restoration of 149 linear feet of streams in the Northeast Cape
Fear River Basin, Cataloging Unit 03030007.
Construction within jurisdictional areas on the property shall begin only after the permittee has made
full payment to the NC EEP and provided a copy of the payment documentation to the Corps, and the
NC EEP has provided written confirmation to the Corps that it agrees to accept responsibility for the
mitigation work required, in compliance with the MOU between the North Carolina Department of
Environment and Natural Resources and the United States Army Corps of Engineers, Wilmington
District, dated November 4, 1998
2. The Permittee shall execute and cause to be recorded in the New Hanover County Register of Deeds the
Conservation Declaration (see attached) for the purpose of maintaining 11.39 acres of waters and
wetlands, as shown on the Resource Preservation Plat (attached), in their natural and/or mitigated state
in perpetuity, prior to the sale or conveyance of any portion or all of the 89.37 acre tract. At the time of
recordation of the Covenants, the Permittee must also record with the New Hanover County Register of
Deeds, a final survey map of the development, sealed by the licensed surveyor, which clearly depicts the
surveyed areas of Conservation and lot/infrastructure layout.
These provisions relating to wetlands cannot be amended or modified without the express written
consent of the U.S. Army Corps of Engineers, Wilmington District. *This includes changes as a result
of any local government drainage easement requirements*.
The permittee shall enforce the terms of the Covenants and, prior to conveyance of the property, shall
take no action on the property described in the Covenants inconsistent with the terms thereof. The
permittee shall provide a copy of the recorded Covenants and recorded Survey to the Corps of Engineers
within 15 days of recording.
Corps Regulatory
ci Date:
/LZIE,zleep-

Action ID Number: SAW-2008-1284 County: New Hanover
Permittee: The City of Wilmington (c/o Tara Duckworth)
Date Permit Issued: December 15, 2008
Project Manager: Kimberly Garvey
Upon completion of the activity authorized by this permit and any mitigation required by the permit,
sign this certification and return it to the following address:
US ARMY CORPS OF ENGINEERS
WILMINGTON DISTRICT
WILMINGTON REGULATORY FIELD OFFICE
POST OFFICE BOX 1890
WILMINGTON, NORTH CAROLINA 28402-1890
Please note that your permitted activity is subject to a compliance inspection by a U. S. Army Corps of
Engineers representative. If you fail to comply with this permit you are subject to permit suspension,
modification, or revocation.
I hereby certify that the work authorized by the above referenced permit has been completed in
accordance with the terms and condition of the said permit, and required mitigation was completed in
accordance with the permit conditions.
Signature of Permittee
Date

Tara Duckworth
City of Wihnington
302 Welland St.,
Wilmington, NC 28402
r-I*-
apralet
,...GRAM
September 18, 2008
Project: Olsen Farm Project
Expiration of Acceptance: June 18, 2009
County: New Hanover County
The purpose of this letter is to notify you that the North Carolina Ecosystem Enhancement Program (NCEEP) is willing to accept
payment for impacts associated with the above referenced project. Please note that this decision does not assure that the payment will
be approved by the permit issuing agencies as mitigation for project impacts. It is the responsibility of the applicant to contact these
agencies to determine if payment to the NCEEP will be approved.
This acceptance is valid for nine months from the date of this letter and is not transferable. If we have not received a. copy of the
Issued 404 Permit/401 Certitication/CAMA permit within this time frame, this acceptance will expire, It is the applicant's
responsibility to send copies of the permits to NCEEP. Once NCEEP receives a copy of the permit(s) an invoice will be issued based
on the required mitigation in that permit and payment must be made prior to conducting the authorized work. The amount of the In
Lieu Fee to be paid to NCEEP by an applicant is calculated based upon the Fee Schedule and policies listed at www.wwp.net.
Based on the information supplied by you the impacts that may require compensatory mitigation are summarized in the following
table.
'River
Basin
Cu
Location
Stream (feet)
Wetlands (acres)
Buffer I
(Sq. Ft.)
Buffer 1I
(Sq. Ft.)
Cold
Cool
Warm
Riparian
Non -Riparian
Coastal Marsh
Impact
Cape Fear
03030007
0
0
149
0
0
0
0
0
Credits
Cape Fcar
03030007
0
0
298
0
0
0
0
0
Upon receipt of payment, EEP will take responsibility for providing the compensatory mitigation. If the regulatory agencies require
mitigation credits greater than indicated above, and the applicant wants NCEEP to be responsible for the additional mitigation, the
applicant will need to submit a mitigation request to NCEEP for approval prior to permit issuance, The mitigation will be performed
in accordance with the Memorandum of Understanding between the N. C. Department of Environment and Natural Resources and the
U. S. Army Corps of Engineers dated November 4, 1998.
If you have any questions or need additional information, please contact Valerie Mitchener at [phone],
Sincerely,
William . Gilmore, PE
Director
cc: Cyndi Karoly, NCDWQ Wetlands/401 Unit
Kim Garvey, USACE-Wilmington
Chad Coburn, NCDWQ-Wilmington
Thomas King, agent
File
Ruhorrg... E ,.. Prott'ct' Oar State,
LIN
North Carolina E-cosystem Enhancement Program, 1652 Mail Service Center, Raleigh, NC 27699-i652 / 919-715-0476 /www,nceen.net

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12

NATIONWIDE PERMIT 14
DEPARTMENT OF THE ARMY
CORPS OF ENGINEERS
FINAL NOTICE OF ISSUANCE AND MODIFICATION OF NATIONWIDE PERMITS
FEDERAL REGISTER
AUTHORIZED MARCH 19, 2007
Linear Transportation Projects_ Activities required for the construction, expansion,
modification, or improvement of linear transportation projects (e.g., roads, highways, railways,
trails, airport runways, and taxiways) in waters of the United States. For linear transportation
projects in non -tidal waters, the discharge cannot cause the loss of greater than 1/2-acre of waters
of the United States. For linear transportation projects in tidal waters, the discharge cannot cause
the loss of greater than 1/3-acre of waters of the United States. Any stream channel modification,
including bank stabilization, is limited to the minimum necessary to construct or protect the
linear transportation project; such modifications must be in the immediate vicinity of the project.
This NWP also authorizes temporary structures, fills, and work necessary to construct the
linear transportation project. Appropriate measures must be taken to maintain normal
downstream flows and minimize flooding to the maximum extent practicable, when temporary
structures, work, and discharges, including cofferdams, are necessary for construction activities,
access fills, or dewatering of construction sites. Temporary fills must consist of materials, and be
placed in a manner, that will not be eroded by expected high flows. Temporary fills must be
removed in their entirety and the affected areas returned to pre -construction elevations. The areas
affected by temporary fills must be revegetated, as appropriate.
This NWP cannot be used to authorize non -linear features commonly associated with
transportation projects, such as vehicle maintenance or storage buildings, parking lots, train
stations, or aircraft hangars.
Notification: The permittee must submit a pre -construction notification to the district
engineer prior to commencing the activity if. (1) the loss of waters of the United States exceeds
I/10 acre; or (2) there is a discharge in a special aquatic site, including wetlands. (See general
condition 27.) (Sections 10 and 404)
Note: Some discharges for the construction of farm roads or forest roads, or temporary
roads for moving mining equipment, may qualify for an exemption under Section 404(f) of the
Clean Water Act (see 33 CFR 323.4).

NATIONWIDE PERMIT CONDITIONS
The following General Conditions r,►ust ue'Ibllowed in order for any authorization by a NWP to
be valid:
1. Navigation. (a) No activity may cause more than a minimal adverse effect on
navigation.
(b) Any safety lights and signals prescribed by the U.S. Coast Guard, through regulations
or otherwise, must be installed and maintained at the permittee's expense on authorized facilities
in navigable waters of the United States.
(c) The permittee understands and agrees that, if future operations by the United States
require the removal, relocation, or other alteration, of the structure or work herein authorized, or
if, in the opinion of the Secretary of the Army or his authorized representative, said structure or
work shall cause unreasonable obstruction to the free navigation of the navigable waters, the
permittee will be required, upon due notice from the Corps of Engineers, to remove, relocate, or
alter the structural work or obstructions caused thereby, without expense to the United States. No
claim shall be made against the United States on account of any such removal or alteration.
2. Aquatic Life Movements. No activity may substantially disrupt the necessary life cycle
movements of those species of aquatic life indigenous to the waterbody, including those species
that normally migrate through the area, unless the activity's primary purpose is to impound
water. Culverts placed in streams must be installed to maintain low now conditions.
3. Spawning Areas. Activities in spawning areas during spawning seasons must be
avoided to the maximum extent practicable. Activities that result in the physical destruction (e.g.,
through excavation, fill, or downstream smothering by substantial turbidity) of an important
spawning area are not authorized.
4. Mi rg atory Bird Breeding Areas. Activities in waters of the United States that serve as
breeding areas for migratory birds must be avoided to the maximum extent practicable.
5. Shellfish Beds. No activity may occur in areas of concentrated shellfish populations,
unless the activity is directly related to a shellfish harvesting activity authorized by NWPs 4 and
48.
6. Suitable Material. No activity may use unsuitable material (e.g., trash, debris, car
bodies, asphalt, etc.). Material used for construction or discharged must be free from toxic
pollutants in toxic amounts (see Section 307 of the Clean Water Act).
7. Water Supply Intakes. No activity may occur in the proximity of a public water supply
intake, except where the activity is for the repair or improvement of public water supply intake
structures or adjacent bank stabilization.
8. Adverse Effects From Impoundments. If the activity creates an impoundment of water,
adverse effects to the aquatic system due to accelerating the passage of water, and/or restricting
its flow must be minimized to the maximum extent practicable.

9. Management of Water Flows. To the maximum extent practicable, the pre -construction
course, condition, capacity, and location of open waters must be maailuta ied for each activity,
including stream channelization and storm water management activities, except as provided
below. The activity must be constructed to withstand expected high flows. The activity must not
restrict or impede the passage of normal or high flows, unless the primary purpose of the activity
is to impound water or manage high flows. The activity may alter the pre -construction course,
condition, capacity, and location of open waters if it benefits the aquatic environment (e.g.,
stream restoration or relocation activities).
10. Fills Within 100-Year Floodplains. The activity must comply with applicable FEMA-
approved state or local floodplain management requirements.
11. Equipment. Heavy equipment working in wetlands or mudflats must be placed on
mats, or other measures must be taken to minimize soil disturbance.
12. Soil Erosion and Sediment Controls. Appropriate soil erosion and sediment controls
must be used and maintained in effective operating condition during construction, and all
exposed soil and other fills, as well as any work below the ordinary high water mark or high tide
line, must be permanently stabilized at the earliest practicable date. Permittees are encouraged to
perform work within waters of the United States during periods of low -flow or no -flow.
13. Removal of TemRgma Fills. Temporary fills must be removed in their entirety and
the affected areas returned to pre -construction elevations. The affected areas must be
revegetated, as appropriate.
14. P�per Maintenance. Any authorized structure or fill shall be properly maintained,
including maintenance to ensure public safety.
15. Wild and Scenic Rivers. No activity may occur in a component of the National Wild
and Scenic River System, or in a river officially designated by Congress as a "study river" for
possible inclusion in the system while the river is in an official study status, unless the
appropriate Federal agency with direct management responsibility for such river, has determined
in writing that the proposed activity will not adversely affect the Wild and Scenic River
designation or study status. Information on Wild and Scenic Rivers may be obtained from the
appropriate Federal land management agency in the area (e.g., National Park Service, U.S. Forest
Service, Bureau of Land Management, U.S. Fish and Wildlife Service).
16. Tribal Rights. No activity or its operation may impair reserved tribal rights, including,
but not limited to, reserved water rights and treaty fishing and hunting rights.
17. Endangered Spgcies. (a) No activity is authorized under any NWP which is likely to
jeopardize the continued existence of a threatened or endangered species or a species proposed
for such designation, as identified under the Federal Endangered Species Act (ESA), or which
will destroy or adversely modify the critical habitat of such species. No activity is authorized
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under any NWP which "may affect" a listed species or critical habitat, unless Section 7
consultation addressing the effects of the proposed activity has been completed.
(b) Federal agencies should follow their own procedures for complying with tl;e
requirements of the ESA. Federal permittees must provide the district engineer with the
appropriate documentation to demonstrate compliance with those requirements.
(c) Non-federal permittees shall notify the district engineer if any listed species or
designated critical habitat might be affected or is in the vicinity of the project, or if the project is
located in designated critical habitat, and shall not begin work on the activity until notified by the
district engineer that the requirements of the ESA have been satisfied and that the activity is
authorized. For activities that might affect Federally -listed endangered or threatened species or
designated critical habitat, the pre -construction notification must include the name(s) of the
endangered or threatened species that may be affected by the proposed work or that utilize the
designated critical habitat that may beaffected by the proposed work. The district engineer will
determine whether the proposed activity "may affect" or will have "no effect" to listed species
and designated critical habitat and will notify the non -Federal applicant of the Corps'
determination within 45 days of receipt of a complete pre -construction notification. In cases
where the non -Federal applicant has identified listed species or critical habitat that might be
affected or is in the vicinity of the project, and has so notified the Corps, the applicant shall not
begin work until the Corps has provided notification the proposed activities will have "no effect"
on listed species or critical habitat, or -until Section 7 consultation has been completed.
(d) As a result of formal or informal consultation with the FWS or NMFS the district
engineer may add species -specific regional endangered species conditions to the NWPs.
(e) Authorization of an activity by a NWP does not authorize the "take" of a threatened or
endangered species as defined under the ESA. In the absence of separate authorization (e.g., an
ESA Section 10 Permit, a Biological Opinion with "incidental take" provisions, etc.) from the
U.S. FWS or the NMFS, both lethal and non -lethal "takes" of protected species are in violation -
of the ESA. Information on the location of threatened and endangered species and their critical
habitat can be obtained directly from the offices of the U.S. FWS and NMFS or their world wide
Web pages at http://www.fws.gov/ and http://www.noaa.gov/fisheries.html respectively.
18. Historic Proep rties. (a) In cases where the district engineer determines that the
activity may affect properties listed, or eligible for listing, in the National Register of Historic
Places, the activity is not authorized, until the requirements of Section 106 of the National
Historic Preservation Act (NHPA) have been satisfied.
(b) Federal permittees should follow their own procedures for complying with the
requirements of Section 106 of the National Historic Preservation Act. Federal permittees must
provide the district engineer with the appropriate documentation to demonstrate compliance with
those requirements.
(c) Non-federal permittees must submit a pre -construction notification to the district
engineer if the authorized activity may have the potential to cause effects to any historic
properties listed, determined to be eligible for listing on, or potentially eligible for listing on the
National Register of Historic Places, including previously unidentified properties. For such
activities, the pre -construction notification must state which historic properties may be affected
by the proposed work or include a vicinity map indicating the location of the historic properties
or the potential for the presence of historic properties. Assistance regarding information on the
location of or potential for the presence of historic resources can be sought from the State
4

Historic Preservation Officer or Tribal Historic Preservation Officer, as appropriate, and the
National Register of Historic Places (see 33 CFR 330.4(g)). The district engineer shall make a
reasonable and good faith effor i to carry out appropriate identification efforts, which may include
background research, consultation, oral history interviews, sample field investigation, and field
survey. Based on the information submitted and these efforts, the district engineer shall
determine whether the proposed activity has the potential to cause an effect on the historic
properties. Where the non -Federal applicant has identified historic properties which the activity
may have the potential to cause effects and so notified the Corps, the non -Federal applicant shall
not begin the activity until notified by the district engineer either that the activity has no potential
to cause effects or that consultation under Section 106 of the NHPA has been completed.
(d) The district engineer will notify the prospective permittee within 45 days of receipt
of a complete pre -construction notification whether NHPA Section 106 consultation is required.
Section 106 consultation is not required when the Corps determines that the activity does not
have the potential to cause effects on historic properties (see 36 CFR 800.3(a)). If NHPA section
106 consultation is required and will occur, the district engineer will notify the non -Federal
applicant that he or she cannot begin work until Section 106 consultation is completed.
(e) Prospective permittees should be aware that section 110k of the NHPA (16 U.S.C.
470h-2(k)) prevents the Corps from granting a permit or other assistance to an applicant who,
with intent to avoid the requirements of Section 106 of the NHPA, has intentionally significantly
adversely affected a historic property to which the permit would relate, or having legal power to
prevent it, allowed such significant adverse effect to occur,_unless the Corps, after consultation
with the Advisory Council on Historic Preservation (ACHP), determines that circumstances
justify granting such assistance despite the adverse effect created or permitted by the applicant.
If circumstances justify granting the assistance, the Corps is required to notify the ACHP and
provide documentation specifying the circumstances, explaining the degree of damage to the
integrity of any historic properties affected, and proposed mitigation. This documentation must
include any views obtained from the applicant, SHPO/THPO, appropriate Indian tribes if the
undertaking occurs on or affects historic properties on tribal lands or affects properties of interest
to those tribes, and other parties known to have a legitimate interest in the impacts to the
permitted activity on historic properties.
19. Designated Critical Resource Waters. Critical resource waters include, NOAA-
designated marine sanctuaries, National Estuarine Research Reserves, state natural heritage sites,
and outstanding national resource waters or other waters officially designated by a state as
having particular environmental or ecological significance and identified by the district engineer
after notice and opportunity for public comment. The district engineer may also designate
additional critical resource waters after notice and opportunity for comment.
(a) Discharges of dredged or fill material into waters of the United States are not
authorized by NWPs 7, 12, 14, 16, 17, 21, 29, 31, 35, 39, 40, 42, 43, 44, 49, and 50 for any
activity within, or directly affecting, critical resource waters, including wetlands adjacent to such
waters.
(b) For NWPs 3, 8, 10, 13, 15, 18, 19, 22, 23, 25, 27, 28, 30, 33, 34, 36, 37, and 38,
notification is required in accordance with general condition 27, for any activity proposed in the
designated critical resource waters including wetlands adjacent to those waters. The district
engineer may authorize activities under these NWPs only after it is determined that the impacts
to the critical resource waters will be no more than minimal.
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20. Mitigation. The district engineer will consider the following factors when
determining appropriate and practicable mitigation necessary io ensure that adverse effects on
the aquatic environment are minimal:
(a) The activity must be designed and constructed to avoid and minimize adverse effects,
both temporary and permanent, to waters of the United States to the maximum extent practicable
at the project site (i.e., on site).
(b) Mitigation in all its forms (avoiding, minimizing, rectifying, reducing, or
compensating) will be required to the extent necessary to ensure that the adverse effects to the
aquatic environment are minimal.
(c) Compensatory mitigation at a minimum one -for -one ratio will be required for all
wetland losses that exceed 1/10 acre and require pre -construction notification, unless the district
engineer determines in writing that some other form of mitigation would be more
environmentally appropriate and provides a project -specific waiver of this requirement. For
wetland losses of 1/10 acre or less that require pre -construction notification, the district engineer
may determine on a case -by -case basis that compensatory mitigation is required to ensure that
the activity results in minimal adverse effects on the aquatic environment. Since the likelihood of
success is greater and the impacts to potentially valuable uplands are reduced, wetland
restoration should be the first compensatory mitigation option considered.
(d) For losses of streams or other open waters that require pre -construction notification,
the district engineer may require compensatory mitigation, such as stream restoration, to ensure
that the activity results in minimal adverse effects on the aquatic environment.
(e) Compensatory mitigation will not be used to increase the acreage losses allowed by
the acreage limits of the NWPs. For example, if an NWP has an acreage limit of 1/2 acre, it
cannot be used to authorize any project resulting in the loss of greater than 1 /2 acre of waters of
the United States, even if compensatory mitigation is provided that replaces or restores some of
the lost waters. However, compensatory mitigation can and should be used, as necessary, to
ensure that a project already meeting the established acreage limits also satisfies the minimal
impact requirement associated with the NWPs.
(f) Compensatory mitigation plans for projects in or near streams or other open waters
will normally include a requirement for the establishment, maintenance, and legal protection
(e.g., conservation easements) of riparian areas next to open waters. In some cases, riparian areas
may be the only compensatory mitigation required. Riparian areas should consist of native
species. The width of the required riparian area will address documented water quality or aquatic
habitat loss concerns. Normally, the riparian area will be 25 to 50 feet wide on each side of the
stream, but the district engineer may require slightly wider riparian areas to address documented
water quality or habitat loss concerns. Where both wetlands and open waters exist on the project
site, the district engineer will determine the appropriate compensatory mitigation (e.g., riparian
areas and/or wetlands compensation) based on what is best for the aquatic environment on a
watershed basis. In cases where riparian areas are determined to be the most appropriate form of
compensatory mitigation, the district engineer may waive or reduce the requirement to provide
wetland compensatory mitigation for wetland losses.
(g) Permittees may propose the use of mitigation banks, in -lieu fee arrangements or
separate activity -specific compensatory mitigation. In all cases, the mitigation provisions will
specify the party responsible for accomplishing and/or complying with the mitigation plan.
R

(h) Where certain functions and services of waters of the United States are permanently
adversely affected, such as the conversion of a forested or scrub -shrub wetland to a herbaceous
wetland in a permanently maintained utility line right-of-,vay, mitigation may be required to
reduce the adverse effects of the project to the minimal level.
21. Water Quality. Where States and authorized Tribes, or EPA where applicable, have
not previously certified compliance of an NWP with CWA Section 401, individual 401 Water
Quality Certification must be obtained or waived (see 33 CFR 330.4(c)). The district engineer or
State or Tribe may require additional water quality management measures to ensure that the
authorized activity does not result in more than minimal degradation of water quality.
22. Coastal Zone Management. In coastal states where an NWP has not previously
received a state coastal zone management consistency concurrence, an individual state coastal
zone management consistency concurrence must be obtained, or a presumption of concurrence
must occur (see 33 CFR 330.4(d)). The district engineer or a State may require additional
measures to ensure that the authorized activity is consistent with state coastal zone management
requirements.
23. Regional and Case -By -Case Conditions. The activity must comply with any regional
conditions that may have been added by the Division Engineer (see 33 CFR 330.4(e)) and with
any case specific conditions added by the Corps or by the state, Indian Tribe, or U.S. EPA in its
section 401 Water Quality Certification, or by the state in its Coastal Zone Management Act
consistency determination.
24. Use of Multiple Nationwide Permits. The use of more than one NWP for a single and
complete project is prohibited, except when the acreage loss of waters of the United States
authorized by the NWPs does not exceed the acreage limit of the NWP with the highest specified
acreage limit. For example, if a road crossing over tidal waters is constructed under NWP 14,
with associated bank stabilization authorized by NWP 13, the maximum acreage loss of waters
of the United States for the total project cannot exceed 1/3-acre.
25. Transfer of Nationwide Permit Verifications. If the permittee sells the property
associated with a nationwide permit verification, the permittee may transfer the nationwide
permit verification to the new owner by submitting a letter to the appropriate Corps district office
to validate the transfer. A copy of the nationwide permit verification must be attached to the
letter, and the letter must contain the following statement and signature:
"When the structures or work authorized by this nationwide permit are still in existence at the
time the property is transferred, the terms and conditions of this nationwide permit, including any
special conditions, will continue to be binding on the new owner(s) of the property. To validate

the transfer of this nationwide permit and the associated liabilities associated with compliance
with its terms and conditions, have the transferee sign and date below."
(Transferee)
(Date)
26. Compliance Certification. Each permittee who received an NWP verification from the
Corps must submit a signed certification regarding the completed work and any required
mitigation. The certification form must be forwarded by the Corps with the NWP verification
letter and will include:
(a) A statement that the authorized work was done in accordance with the NWP
authorization, including any general or specific conditions;
(b) A statement that any required mitigation was completed in accordance with the permit
conditions; and
(c) The signature of the permittee certifying the completion of the work and mitigation.
27. Pre -Construction Notification. (a) Timing. Where required by the terms of the NWP,
the prospective permittee must notify the district engineer by submitting a pre -construction
notification (PCN) as early as possible. The district engineer must determine if the PCN is
complete within 30 calendar days of the date of receipt and, as a general rule, will request
additional information necessary to make the PCN complete only once. However, if.the
prospective permittee does not provide all of the requested information, then the district engineer
will notify the prospective permittee that the PCN is still incomplete and the PCN review process
will not commence until all of the requested information has been received by the district
engineer. The prospective permittee shall not begin the activity until either:
(1) He or she is notified in writing by the district engineer that the activity may proceed
under the NWP with any special conditions imposed by the district or division engineer; or
(2) Forty-five calendar days have passed from the district engineer's receipt of the
complete PCN and the prospective permittee has not received written notice from the district or
division engineer. However, if the permittee was required to notify the Corps pursuant to general
condition. 17 that listed species or critical habitat might affected or in the vicinity of the project,
or to notify the Corps pursuant to general condition 18 that the activity may have the potential to
cause effects to historic properties, the permittee cannot begin the activity until receiving written
notification from the Corps that is "no effect" on listed species or "no potential to cause effects"
on historic properties, or that any consultation required under Section 7 of the Endangered
Species Act (see 33 CFR 330.4(f)) and/or Section 106 of the National Historic Preservation (see
33 CFR 330.4(g)) is completed. Also, work cannot begin under NWPs 21, 49, or 50 until the
permittee has received written approval from the Corps. If the proposed activity requires a
written waiver to exceed specified limits of an NWP, the permittee cannot begin the activity until
the district engineer issues the waiver. If the district or division engineer notifies the permittee in
writing that an individual permit is required within 45 calendar days of receipt of a complete
PCN, the permittee cannot begin the activity until an individual permit has been obtained.

Subsequently, the permittee's right to proceed under the NWP may be modified, suspended, or
revoked only in accordance with the procedure set forth in 33 CFR 330.5(d)(2).
(b) Contents of Pre -Construction Notif cstion: The PCN must be in writing and include
the following information:
(1) Name, address and telephone numbers of the prospective permittee;
(2) Location of the proposed project;
(3) A description of the proposed project; the project's purpose; direct and indirect
adverse environmental effects the project would cause; any other NWP(s), regional general
permit(s), or individual permit(s) used or intended to be used to authorize any part of the
proposed project or any related activity. The description should be sufficiently detailed to allow
the district engineer to determine that the adverse effects of the project will be minimal and to
determine the need for compensatory mitigation. Sketches should be provided when necessary
to show that the activity complies with the terms of the NWP. (Sketches usually clarify the
project and when provided result in a quicker decision.);
(4) The PCN must include a delineation of special aquatic sites and other waters of the
United States on the project site. Wetland delineations must be prepared in accordance with the
current method required by the Corps. The permittee may ask the Corps to delineate the special
aquatic sites and other waters of the United States, but there may be a delay if the Corps does the
delineation, especially if the project site is large or contains many waters of the United States.
Furthermore, the 45 day -period will not start until the delineation has been submitted.to or
completed by the Corps, where appropriate;
(5) If the proposed activity will result in the loss of greater than 1 /.10 acre of wetlands and
a PCN is required, the prospective permittee must submit a statement describing how the
mitigation requirement will be satisfied. As an alternative, the prospective permittee may submit
a conceptual or detailed mitigation plan.
(6) If any listed species or designated critical habitat might be affected or is in the vicinity
of the project, or if the project is located in designated critical habitat, for non -Federal applicants
the PCN must include the name(s) of those endangered or threatened species that might be
affected by the proposed work or utilize the designated critical habitat that may be affected by
the proposed work. Federal applicants must provide documentation demonstrating compliance
with the Endangered Species Act; and
(7) For an activity that may affect a historic property listed on, determined to be eligible
for listing on, or potentially eligible for listing on, the National Register of Historic Places, for
non -Federal applicants the PCN must state which historic property may be affected by the
proposed work or include a vicinity map indicating the location of the historic property. Federal
applicants must provide documentation demonstrating compliance with Section 106 of the
National Historic Preservation Act.
(c) Form of Pre -Construction Notification: The standard individual permit application
form (Form ENO 4345) may be used, but the completed application form must clearly indicate
that it is a PCN and must include all of the information required in paragraphs (b)(1) through (7)
of this general condition. A letter containing the required information may also be used.
(d) Agency Coordination: (1) The district engineer will consider any comments from
Federal and state agencies concerning the proposed activity's compliance with the terms and
conditions of the NWPs and the need for mitigation to reduce the project's adverse
environmental effects to a minimal level.
9

(2) For all NWP 48 activities requiring pre -construction notification and for other NWP
activities requiring pre -construction notification to the district engineer that result in the loss of
greater than 1/2-acre of waters of the United States, the district engineer will immediately
provide (e.g., via facsimile transmission, overnight mail, or other expeditious manner) a copy of
the PCN to the appropriate Federal or state offices (U.S. FWS, state natural resource or water
quality agency, EPA, State Historic Preservation Officer (SHPO) or Tribal Historic Preservation
Office (THPO), and, if appropriate, the NMFS). With the exception of NWP 37, these agencies
will then have 10 calendar days from the date the material is transmitted to telephone or fax the
district engineer notice that they intend to provide substantive, site -specific comments. If so
contacted by an agency, the district engineer will wait an additional 15 calendar days before
making a decision on the pre -construction notification. The district engineer will fully consider
agency comments received within the specified time frame, but will provide no response to the
resource agency, except as provided below. The district engineer will indicate in the
administrative record associated with each pre -construction notification that the resource
agencies' concerns were considered. For NWP 37, the emergency watershed protection and
rehabilitation activity may proceed immediately in cases where there is an unacceptable hazard
to life or a significant loss of property or economic hardship will occur. The district engineer will
consider any comments received to decide whether the NWP 37 authorization should be
modified, suspended, or revoked in accordance with the procedures at 33 CFR 330.5.
(3) In cases of where the prospective permittee is not a Federal agency, the district
engineer will provide a response to NMFS within 30 calendar days of receipt of any Essential
Fish Habitat conservation recommendations, as required by Section 305(b)(4)(B) of the
Magnuson -Stevens Fishery Conservation and Management Act.
(4) Applicants are encouraged to provide the Corps multiple copies of pre -construction
notifications to expedite agency coordination.
(5) For NWP 48 activities that require reporting, the district engineer will provide a copy
of each report within 10 calendar days of receipt to the appropriate regional office of the NMFS.
(e) District Engineer's Decision: In reviewing the PCN for the proposed activity, the
district engineer will determine whether the activity authorized by the NWP will result in more
than minimal individual or cumulative adverse environmental effects or may be contrary to the
public interest. If the proposed activity requires a PCN and will result in a loss of greater than
1/10 acre of wetlands, the prospective permittee should submit a mitigation proposal with the
PCN. Applicants may also propose compensatory mitigation for projects with smaller impacts.
The district engineer will consider any proposed compensatory mitigation the applicant has
included in the proposal in determining whether the net adverse environmental effects to the
aquatic environment of the proposed work are minimal. The compensatory mitigation proposal
may be either conceptual or detailed. If the district engineer determines that the activity complies
with the terns and conditions of the NWP and that the adverse effects on the aquatic
environment are minimal, after considering mitigation, the district engineer will notify the
permittee and include any conditions the district engineer deems necessary. The district engineer
must approve any compensatory mitigation proposal before the permittee commences work. If
the prospective permittee elects to submit a compensatory mitigation plan with the PCN, the
district engineer will expeditiously review the proposed compensatory mitigation plan. The
district engineer must review the plan within 45 calendar days of receiving a complete PCN and
determine whether the proposed mitigation would ensure no more than minimal adverse effects
on the aquatic environment. If the net adverse effects of the project on the aquatic environment
10

(after consideration of the compensatory mitigation proposal) are determined by the district
engineer to be minimal, the district engineer will provide a timely written response to the
applicant. The response will Ovate that the projc-rt can proceed under Clio terms and conditions of
the NWP.
If the district engineer determines that the adverse effects of the proposed work are more
than minimal, then the district engineer will notify the applicant either: (1) That the project does
not qualify for authorization under the NWP and instruct the applicant on the procedures to seek
authorization under an individual permit; (2) that the project is authorized under the NWP
subject to the applicant's submission of a mitigation plan that would reduce the adverse effects
on the aquatic environment to the minimal level; or (3) that the project is authorized under the
NWP with specific modifications or conditions. Where the district engineer determines that
mitigation is required to ensure no more than minimal adverse effects occur to the aquatic
environment, the activity will be authorized within the 45-day PCN period. The authorization
will include the necessary conceptual or specific mitigation or a requirement that the applicant
submit a mitigation plan that would reduce the adverse effects on the aquatic environment to the
minimal level. When mitigation is required, no work in waters of the United States may occur
until the district engineer has approved a specific mitigation plan.
28. Single and Complete Project. The activity must be a single and complete project. The
same NWP cannot be used more than once for the same single and complete project.
FURTHER INFQRMATION
1. District Engineers have authority to determine if an activity complies with the terms
and conditions of an NWP.
2. NWPs do not obviate the need to obtain other federal, state, or local permits,
approvals, or authorizations required by law.
3. NWPs do not grant any property rights or exclusive privileges.
4. NWPs do not authorize any injury to the property or rights of others.
5. NWPs do not authorize interference with any existing or proposed Federal project.
DEFINITIONS
Best management practices (AA_ s): Policies, practices, procedures, or structures
implemented to mitigate the adverse environmental effects on surface water quality resulting
from development. BMPs are categorized as structural or non-structural.
Compensatory mitigation: The restoration, establishment (creation), enhancement, or
preservation of aquatic resources for the purpose of compensating for unavoidable adverse
impacts which remain after all appropriate and practicable avoidance and minimization has been
achieved.
Currently serviceable: Useable as is or with some maintenance, but not so degraded as to
essentially require reconstruction.
Discharge: The term "discharge" means any discharge of dredged or fill material.
Enhancement: The manipulation of the physical, chemical, or biological characteristics of
an aquatic resource to heighten, intensify, or improve a specific aquatic resource function(s).
Enhancement results in the gain of selected aquatic resource function(s), but may also lead to a
11

decline in other aquatic resource function(s). Enhancement does not result in a gain in aquatic
resource area.
Ephemeral streai7: An ephe,-,;eiai -tcO- - l,as fluwixig water only during, and for a short
duration after, precipitation events in a typical year. Ephemeral stream beds are located above the
water table year-round. Groundwater is not a source of water for the stream. Runoff from rainfall
is the primary source of water for stream flow.
Establishment (creation): The manipulation of the physical, chemical, or biological
characteristics present to develop an aquatic resource that did not previously exist at an upland
site. Establishment results in a gain in aquatic resource area.
Historic Property: Any prehistoric or historic district, site (including archaeological
site), building, structure, or other object included in, or eligible for inclusion in, the National
Register of Historic Places maintained by the Secretary of the Interior. This term includes
artifacts, records, and remains that are related to and located within such properties. The term
includes properties of traditional religious and cultural importance to an Indian tribe or Native
Hawaiian organization and that meet the National Register criteria (36 CFR part 60).
Independent utility: A test to determine what constitutes a single and complete project in
the Corps regulatory program. A project is considered to have independent utility if it would be
constructed absent the construction of other projects in the project area. Portions of a multi -phase
project that depend upon other phases of the project do not have independent utility. Phases of a
project that would be constructed even if the other phases were not built can be considered as
separate single and complete projects with independent utility.
Intermittent stream: An intermittent stream has flowing water during certain times of the
year, when groundwater provides water for stream flow. During dry periods, intermittent streams
may not have flowing water. Runoff from rainfall is a supplemental source of water for stream
flow.
Loss of waters of the United States: Waters of the United States that are permanently
adversely affected by filling, flooding, excavation, or drainage because of the regulated activity.
Permanent adverse effects include permanent discharges of dredged or fill material that change
an aquatic area to dry land, increase the bottom elevation of a waterbody, or change the use of a
waterbody. The acreage of loss of waters of the United States is a threshold measurement of the
impact to jurisdictional waters for determining whether a project may qualify for an NWP; it is
not a net threshold that is calculated after considering compensatory mitigation that may be used
to offset losses of aquatic functions and services. The loss of stream bed includes the linear feet
of stream bed that is filled or excavated. Waters of the United States temporarily filled, flooded,
excavated, or drained, but restored to pre-constniction contours and elevations after construction,
are not included in the measurement of loss of waters of the United States. Impacts resulting
from activities eligible for exemptions under Section 404(f) of the Clean Water Act are not
considered when calculating the loss of waters of the United States.
Non -tidal wetland: A non -tidal wetland is a wetland that is not subject to the ebb and
flow of tidal waters. The definition of a wetland can be found at 33 CFR 328.3(b). Non -tidal
wetlands contiguous to tidal waters are located landward of the high tide line (i.e., spring high
tide line).
Open water: For purposes of the NWPs, an open water is any area that in a year with
normal patterns of precipitation has water flowing or standing above ground to the extent that an
ordinary high water mark can be determined. Aquatic vegetation within the area of standing or
12

flowing water is either non -emergent, sparse, or absent. Vegetated shallows are considered to be
open waters. Examples of "open waters" include rivers, streams, lakes, and ponds.
CYdingry,.''igh R"Wer Mark: An ordinary high water mark is a ire on the shore
established by the fluctuations of water and indicated by physical characteristics, or by other
appropriate means that consider the characteristics of the surrounding areas (see 33 CFR
328.3(e)).
Perennial stream: A perennial stream has flowing water year-round during a typical year.
The water table is located above the stream bed for most of the year. Groundwater is the primary
source of water for stream flow. Runoff from rainfall is a supplemental source of water for
stream flow.
Practicable: Available and capable of being done after taking into consideration cost,
existing technology, and logistics in light of overall project purposes.
Pre -construction notification: A request submitted by the project proponent to the Corps
for confirmation that a particular activity is authorized by nationwide permit. The request may be
a permit application, letter, or similar document that includes information about the proposed
work and its anticipated environmental effects. Pre -construction notification may be required by
the terms and conditions of a nationwide permit, or by regional conditions. A pre -construction
notification may be voluntarily submitted in cases where pre -construction notification is not
required and the project proponent wants confirmation that the activity is authorized by
nationwide permit.
Preservation: The removal of a threat to, or preventing the decline of, aquatic resources
by an action in or near those aquatic resources. This term includes activities commonly
associated with the protection and maintenance of aquatic resources through the implementation
of appropriate legal and physical mechanisms. Preservation does not result in a gain of aquatic
resource area or functions.
Re-establishment: The manipulation of the physical, chemical, or biological
characteristics of a site with the goal of returning natural/historic functions to a former aquatic
resource. Re-establishment results in rebuilding a former aquatic resource and results in a gain in
aquatic resource area.
Rehabilitation: The manipulation of the physical, chemical, or biological characteristics
of a site with the goal of repairing natural/historic functions to a degraded aquatic resource.
Rehabilitation results in a gain in aquatic resource function, but does not result in a gain in
aquatic resource area.
Restoration: The manipulation of the physical, chemical, or biological characteristics of a
site with the goal of returning natural/historic functions to a former or degraded aquatic resource.
For the purpose of tracking net gains in aquatic resource area, restoration is divided into two
categories: re-establishment and rehabilitation.
Riffle and opo l complex: Riffle and pool complexes are special aquatic sites under the
404(b)(1) Guidelines. Riffle and pool complexes sometimes characterize steep gradient sections
of streams. Such stream sections are recognizable by their hydraulic characteristics. The rapid
movement of water over a course substrate in riffles results in a rough flow, a turbulent surface,
and high dissolved oxygen levels in the water. Pools are deeper areas associated with riffles. A
slower stream velocity, a streaming flow, a smooth surface, and a finer substrate characterize
Pools.
Riparian areas: Riparian areas are lands adjacent to streams, lakes, and estuarine -marine
shorelines. Riparian areas are transitional between terrestrial and aquatic ecosystems, through
13

which surface and subsurface hydrology connects waterbodies with their adjacent uplands.
Riparian areas provide a variety of ecological functions and services and help improve or
maintain local water quality. (See general condition 20 j
Shellfish seeding. The placement of shellfish seed and/or suitable substrate to increase
shellfish production. Shellfish seed consists of immature individual shellfish or individual
shellfish attached to shells or shell fragments (i.e., spat on shell). Suitable substrate may consist
of shellfish shells, shell fragments, or other appropriate materials placed into waters for shellfish
habitat.
Single and complete The term "single and complete project" is defined at 33
CFR 330.2(i) as the total project proposed or accomplished by one owner/developer or
partnership or other association of owners/developers. A single and complete project must have
independent utility (see definition). For linear projects, a "single and complete project" is all
crossings of a single water of the United States (i.e., a single waterbody) at a specific location.
For linear projects crossing a single waterbody several times at separate and distant locations,
each crossing is considered a single and complete project. However, individual channels in a
braided stream or river, or individual arms of a large, irregularly shaped wetland or lake, etc., are
not separate waterbodies, and crossings of such features cannot be considered separately.
Stormwater management: Stormwater management is the mechanism for controlling
stormwater runoff for the purposes of reducing downstream erosion, water quality degradation,
and flooding and mitigating the adverse effects of changes in land use on the aquatic
environment.
Stormwater management facilities: Stormwater management facilities are those facilities,
including but not limited to, stormwater retention and detention ponds and best management
practices, which retain water for a period of time to control runoff and/or improve the quality
(i.e., by reducing the concentration of nutrients, sediments, hazardous substances and other
pollutants) of stormwater runoff.
Stream be The substrate of the stream channel between the ordinary high water marks.
The substrate may be bedrock or inorganic particles that range in size from clay to boulders.
Wetlands contiguous to the stream bed, but outside of the ordinary high water marks, are not
considered part of the stream bed.
Stream channelization: The manipulation of a stream's course, condition, capacity, or
location that causes more than minimal interruption of normal stream processes. A channelized
stream remains a water of the United States.
Structure: An object that is arranged in a definite pattern of organization. Examples of
structures include, without limitation; any pier, boat dock, boat ramp, wharf, dolphin, weir,
boom, breakwater, bulkhead, revetment, riprap, jetty, artificial island, artificial reef, permanent
mooring structure, power transmission line, permanently moored floating vessel, piling, aid to
navigation, or any other manmade obstacle or obstruction.
Tidal wetland: A tidal wetland is a wetland (i.e., water of the United States) that is
inundated by tidal waters. The definitions of a wetland and tidal waters can be found at TI [`FR
328.3(b) and 33 CFR 328.3(f), respectively. Tidal waters rise and fall in a predictable and
measurable rhythm or cycle due to the gravitational pulls of the moon and sun. Tidal waters end
where the rise and fall of the water surface can no longer be practically measured in a predictable
rhythm due to masking by other waters, wind, or other effects. Tidal wetlands are located
channelward of the high tide line, which is defined at 33 CFR 328.3(d).
14

Vegetated shallows: Vegetated shallows are special aquatic sites under the 404(b)(1)
Guidelines. They are areas that are permanently inundated and under normal circumstances have
rooted aquatic WegcIatIon, such as seagrasses in „miazine and estuarine systems and a variety on
vascular rooted plants in freshwater systems.
Water bodv: For purposes of the NWPs, a waterbody is a jurisdictional water of the
United States that, during a year with normal patterns of precipitation, has water flowing or
standing above ground to the extent that an ordinary high water mark (OHWM) or other
indicators of jurisdiction can be determined, as well as any wetland area (see 33 CFR 328.3(b)).
If a jurisdictional wetland is adjacent --meaning bordering, contiguous, or neighboring --to a
jurisdictional waterbody displaying an OHWM or other indicators of jurisdiction, that waterbody
and its adjacent wetlands are considered together as a single aquatic unit (see 33 CFR
328.4(c)(2)). Examples of "waterbodies" include streams, rivers, lakes, ponds, and wetlands.
15

REGIONAL CONDITIONS FOR NATIONWIDE PERMITS IN THE WILMINGTON
DISTRICT
1.0 Excluded Waters
The Corps has identified waters that will be excluded from the use of all NWP's during certain
timeframes. These waters are:
1.1. Anadromous Fish Spawning Areas
Waters of the United States identified by either the North Carolina Division of Marine Fisheries
(NCDMF) or the North Carolina Wildlife Resources Commission (NCWRC) as anadromous fish
spawning areas are excluded during the period between February 15 and June 30, without prior
written approval from NCDMF or NCWRC and the Corps.
1.2. Trout Waters Moratorium
Waters of the United States in the twenty-five designated trout counties of North Carolina are
excluded during the period between October 15 and April 15 without prior written approval from
the NCWRC. (see Section I. b. 7. for a list of the twenty-five trout counties).
1.3. Sturgeon Spawning Areas
Waters of the United States designated as sturgeon spawning areas are excluded during the
period between February 1 and June 30, without prior written approval from the National Marine
Fisheries Service (NMFS).
2.0 Waters Requiring Additional Notification
The Corps has identified waters that will be subject to additional notification requirements for
activities authorized by all NWP's. These waters are:
2.1. Western NC Counties that Drain to Designated Critical Habitat
Waters of the U.S. that requires a Pre -Construction Notification pursuant to General Condition
27 (PCN) and located in the sixteen counties listed below, applicants must provide a copy of the
PCN to the US Fish and Wildlife Service, 160 Zillicoa Street, Asheville, North Carolina 28805.
This PCN must be sent concurrently to the US Fish and Wildlife Service and the Corps Asheville
Regulatory Field Office. Please see General Condition 17 for specific notification requirements
related to Federally Endangered Species and the following website for information on the
location of designated critical habitat.
Counties with tributaries that drain to designated critical habitat that require notification to the
Asheville US Fish and Wildlife Service: Avery, Cherokee, Forsyth, Graham, Haywood,
16

Henderson, Jackson, Macon Mecklenburg, Mitchell, Stokes, Surry, Swain, Transylvania, Union
and Yancey.
Website and office addresses for Endangered Species Act Information:
The Wilmington District has developed the following website for applicants which provide
guidelines on how to review linked websites and maps in order to fulfill NWP general condition
17 requirements.
http://www.saw.usace.army.mi 1/wetlands/ESA
Applicants who do not have internet access may contact the appropriate US Fish and Wildlife
Service offices or the US Army Corps of Engineers office listed below.
US Fish and Wildlife Service
Asheville Field Office
160 Zillicoa Street
Asheville, NC 28801
Telephone: [phone]
Asheville US Fish and Wildlife Service Office counties: All
counties west of and including Anson, Stanly, Davidson, Forsyth and Stokes Counties
US Fish and Wildlife Service
Raleigh Field Office
Post Office Box 33726
Raleigh, NC 27636-3726
Telephone: [phone]
Raleigh US Fish and Wildlife Service Office counties: all counties east of and including
Richmond, Montgomery, Randolph, Guilford, and Rockingham Counties.
2.2. Special Designation Waters
Prior to the use of any NWP in any of the following North Carolina identified waters and
contiguous wetlands, applicants must comply with Nationwide Permit General Condition 27
(PCN). The North Carolina waters and contiguous wetlands that require additional notification
requirements are:
"Outstanding Resource Waters" (ORW) and "High Quality Waters" (HQW) (as designated by
the North Carolina Environmental Management Commission), or
"Inland Primary Nursery Areas" (IPNA) (as designated by the North Carolina Wildlife
Resources Commission), or "Contiguous Wetlands" (as defined by the North Carolina
Environmental Management Commission), or "Primary Nursery Areas" (PNA) (as designated by
the North Carolina Marine Fisheries Commission).

2.3, troasta; Area ivrarvagewieW Aut (CAMA) Areas of Fnvironmentai Concern
Non -Federal applicants for any NWP in a designated "Area of Environmental Concern" (AEC)
in the twenty (20) counties of Eastern North Carolina covered by the North Carolina Coastal
Area Management Act (CAMA), must also obtain the required CAMA permit. Construction
activities for non -Federal projects may not commence until a copy of the approved CAMA
permit is furnished to the appropriate Wilmington District Regulatory Field Office (Wilmington
Field Office — P.O. Box 1890, Wilmington, NC 28402 or Washington Field Office — P.O. Box
1000, Washington, NC 27889).
2.4. Barrier Islands
Prior to the use of any NWP on a barrier island of North Carolina, applicants must comply with
Nationwide Permit General Condition 27 (PCN).
2.5. Mountain or Piedmont Bogs
Prior to the use of any NWP in a "Mountain or Piedmont Bog" of North Carolina, applicants
shall comply with Nationwide Permit General Condition 27 (PCN).
Note: The following wetland community types identified in the N.C. Natural Heritage Program
document, "Classification of Natural communities of North Carolina (Michael P. Schafale and
Alan S. Weakley, 1990), are subject to this regional condition.
Mountain Bogs
Piedmont Bogs
Swamp Forest -Bog Complex
Upland depression Swamp
Forest
Swamp Forest -Bog Complex
(Spruce Subtype)
Southern Appalachian Bog
(Northern Sub
Southern Appalachian Bog
Southern Sub
Southern Appalachian Fen
2.6. Animal Waste Facilities
Prior to use of any NWP for construction of animal waste facilities in waters of the US, including
wetlands, applicants shall comply with Nationwide Permit General Condition 27 (PCN).
2.7. Trout Waters
Prior to any discharge of dredge or fill material into streams or waterbodies within the twenty-
five (25) designated trout counties of North Carolina, the applicant shall comply with
18

Nationwide Permit General Condition 27 (PCN). The applicant shall also provide a copy of the
notification to the appropriate NCWRC office to facilitate the determination of any potential
impacts to designated Trout Waters. Notification to the Corps of Engineers will include
statement with the name of the NCWRC biologist contacted, the date of the notification, the
location of work, a delineation of wetlands, a discussion of alternatives to working in the
mountain trout waters, why alternatives were not selected, and a plan to provide compensatory
mitigation for all unavoidable adverse impacts to mountain trout waters.
NCWRC and NC Trout Counties
Mr. Ron Linville
Western Piedmont Region
Coordinator
Alleghany
Caldwell
Watauga
3855 Idlewild Road
Ashe
Mitchell
Wilkes
Kernersville, NC 27284-9180
1 Avery
I Stokes
Telephone: [phone]
Burke I
Su
Mr. Dave McHenry
Mountain Region Coordinator
Buncombe
Henderson
Polk
20830 Great Smoky Mtn.
Expressway
Cherokee
Jackson
Rutherford
Waynesville, NC 28786
Clay
Macon
Swain
Telephone: [phone]
Graham
Madison
Transylvania
Fax: [phone]
Haywood
McDowell
Yancey
3.0 List of Corps Regional Conditions for All Nationwide Permits
The following conditions apply to all Nationwide Permits in the Wilmington District:
3.1. Limitation of Loss of Perennial Stream Bed
NWPs may not be used for activities that may result in the loss or degradation of greater than
300 total linear feet of perennial streams. The NWPs may not be used for activities that may
result in the loss or degradation of greater than 300 total linear feet of ephemeral and interrittent
streams that exhibit important aquatic function(s)* Loss of stream includes the linear feet of
stream bed that is filled, excavated, or flooded by the proposed activity. The District
Commander can waive the 300 linear foot limit for ephemeral and intermittent streams on a case -
by -case basis if he determines that the proposed activity will result in minimal individual and
cumulative adverse impacts to the aquatic environment. Waivers for the loss of ephemeral and
intermittent streams must be in writing. This waiver only applies to the 300 linear feet threshold
for NWPs. Mitigation may still be required for impacts to ephemeral and intermittent streams,
on a case -by -case basis, depending on the impacts to the aquatic environment of the proposed
project. f*Note: The Corps uses the Stream Quality Assessment Worksheet, located with Permit
Information on the Regulatory Program Web Site, to aid in the determination of aquatic function
within the intermittent stream channel.]
19

3.2. Mitigation for Loss of Stream Bed Exceeding 150 Feet
For any NWP that results in a loss of more than 150 linear feet of perennial and/or
ephemeral/intermittent stream, the applicant shall provide a mitigation proposal to compensate
for the loss of aquatic function associated with the proposed activity. For stream losses less than
150 linear feet, that require a PCN, the District Commander may determine, on a case -by -case
basis that compensatory mitigation is required to ensure that the activity results in minimal
adverse effect on the aquatic environment.
3.3. Pre -construction Notification for Loss of Streambed Exceeding 150 Feet.
Prior to use of any NWP for any activity which impacts more than 150 total linear feet of
perennial stream or ephemeral/ intermittent stream, the applicant must comply with Nationwide
Permit General Condition 27 (PCN). This applies to NWPs that do not have specific notification
requirements. If a NWP has specific notification requirements, the requirements of the NWP
should be followed.
3.4. Restriction on Use of Live Concrete
For all NWPs which allow the use of concrete as a building material, measures will be taken to
prevent live or fresh concrete, including bags of uncured concrete, from coming into contact with
waters of the state until the concrete has hardened.
3.5. Requirements for Using Riprap for Bank Stabilization
For all NWPs that allow for the use of riprap material for bank stabilization, the following
measures shall be applied:
3.5.1. Filter cloth must be placed underneath the riprap as an additional requirement of its use in
North Carolina waters.
3.5.2. The placement of riprap shall be limited to the areas depicted on submitted work plan
drawings.
3.5.3. The riprap material shall be clean and free from loose dirt or any pollutant except in trace
quantities that would not have an adverse environmental effect.
3.5.4. It shall be of a size sufficient to prevent its movement from the authorized alignment by
natural forces under normal conditions.
3.5.5. The riprap material shall consist of clean rock or masonry material such as, but not limited
to, granite, marl, or broken concrete.
20

3.5.6. A waiver from the specifications in this Regional Condition may be requested in writing.
The waiver will only be issued if it can be demonstrated that the impacts of complying with this
Regional condition would result in greater adverse impacts to the aquatic environment.
3.6. Safe Passage Requirements for Culvert Placement
For all NWPs that involve the construction/installation of culverts, measures will be included in
the construction/installation that will promote the safe passage of fish and other aquatic
organisms. The dimension, pattern, and profile of the stream above and below a pipe or culvert
should not be modified by widening the stream channel or by reducing the depth of the stream in
connection with the construction activity. The width, height, and gradient of a proposed opening
should be such as to pass the average historical low flow and spring flow without adversely
altering flow velocity. Spring flow should be determined from gage data, if available. In the
absence of such data, bankfull flow can be used as a comparable level.
In the twenty (20) counties of North Carolina designated as coastal counties by the Coastal Area
Management Act (CAMA): All pipe and culvert bottoms shall be buried at least one foot below
normal bed elevation when they are placed within the Public Trust Area of Environmental
Concern (AEC) and/or the Estuarine Waters AEC as designated by CAMA, and/or all streams
appearing as blue lines on United States Geological Survey (USGS) quad sheets.
Approach Fill I Bankfiill elowstreambed
to appmpraM
depth Ofmquired).
Stream
Bottom
In all other counties: Culverts greater than 48 inches in diameter will be buried at least one foot
below the bed of the stream. Culverts 48 inches in diameter or less shall be buried or placed on
the stream bed as practicable and appropriate to maintain aquatic passage, and every effort shall
be made to maintain the existing channel slope. The bottom of the culvert must be placed at a
depth below the natural stream bottom to provide for passage during drought or lotkr flaky
conditions.
Destabilizing the channel and head cutting upstream should be considered in the placement of
the culvert.
A waiver from the depth specifications in this condition may be requested in writing. The waiver
will be issued if it can be demonstrated that the proposal would result in the least impacts to the
aquatic environment.
All counties: Culverts placed in wetlands do not have to be buried.
21

3.7. Notification to NCDENR Shellfish Sanitation Section
Applicants shall notify the NCDENR Shellfish Sanitation Section prior to dredging in or
removing sediment from an area closed to shell fishing where the effluent may be released to an
area open for shell fishing or swimming in order to avoid contamination from the disposal area
and cause a temporary shellfish closure to be made. Such notification shall also be provided to
the appropriate Corps of Engineers Regulatory ]Meld Office. Any disposal of sand to the ocean
beach should occur between November 1 and April 30 when recreational usage is low. Only
clean sand should be used and no dredged sand from closed shell fishing areas may be used. If
beach disposal were to occur at times other than stated above or if sand from a closed shell
fishing area is to be used, a swimming advisory shall be posted, and a press release shall be
issued.
3.8. Preservation of Submerged Aquatic Vegetation
Adverse impacts to Submerged Aquatic Vegetation (SAV) are not authorized by any NWP
within any of the twenty coastal counties defined by North Carolina's Coastal Area Management
Act of 1974 (CAMA).
4.0 Additional Regional Conditions Applicable to Specific Nationwide Permits
The following regional conditions are required for NWP #14 - Linear Transportation Crossings:
4.1. Natural Channel Design
Applicants shall employ natural channel design (see definition below) to the maximum extent
practicable for stream relocations. In the event it is not practicable to employ natural channel
design, any stream relocation shall be considered a permanent impact and the applicant shall
provide a mitigation plan to compensate for the loss of aquatic function associated with the
proposed activity.
Natural Channel Design: A geomorphologic approach to stream restoration based on an
understanding of valley type, general watershed conditions, dimension, pattern, profile,
hydrology and sediment transport of natural, stable channels (reference condition) and applying
this understanding to the reconstruction of a stable channel.
4.2. Maintenance of Bank -full Flows
Bank -full flows (or less) shall be accommodated through maintenance of the existing bank -full
channel cross sectional area. Additional culverts at such crossings shall be allowed only to
receive flows exceeding bank -full.
22

Approach Fill
Roadway
BankfWl
Baffle/ Stream
Blockage Bottom
Culvert buried
belowstaeambed
to appropriate
depth (ifrequired).
4 3. Maintenance of Floodplain Elevation
Where adjacent floodplain is available, flows exceeding bank -full should be accommodated by
installing culverts at the floodplain elevation.
.4.4. Prohibition to Create Upland from Waters of the US
This NWP authorizes only upland to upland crossings and cannot be used in combination with
Nationwide Permit 18 to create upland within waters of the United States, including wetlands.
Anninwh Fill
R,oaaway
nooaplain
Elevation
4.5. Tidal Water Restrictions
This NWP cannot be used for private projects located in tidal waters or tidal wetlands.
23

C DIVISION OF WATER QUALITY - GENERAL CERTIFICATION CONDITIONS
For the most recent General Ce, fi#ication conditions, call the NC- Division of Water Quality,
Wetlands/401 Certification Unit at [phone] or access the following website:
http://h2o.enr.state. nc.us/ncwetlands/certs.html
NC DIVISION OF COASTAL MANAGEMENT --STATE CONSISTENCY
In a letter dated May 7, 2007, the North Carolina Division of Coastal Management found this
NWP consistent with the North Carolina Coastal Zone Management Program. Updates on
CAMA Consistency for NC can be found on the NC DCM web site at:
http://dcm2.enr.state.nc.us/Permits/consist.htm
EASTERN BAND OF THE CHEROKEE INDIANS TRIBAL WATER QUALITY
CERTIFIC Tel IONS
In a letter dated May 8, 2007, US EPA, on behalf of the Eastern Band of Cherokee Indians,
provided Tribal General Conditions for Nationwide Permits on Cherokee Indian Reservation.
These Tribal General Conditions are located on the Corps website at:
http://www.saw.usace.army.mil/WETLANDS/NWP2007/EBCI-certs.htmi
Citations:
2007 Nationwide Permits Public Notice for Final Issue Date: March 15, 2007
Correction Notice for Nationwide Permits, Federal Register / Vol. 72, No. 88 / Tuesday, May 8,
2007 / Notices p.26082
2007 SAW Regional Conditions - Authorized June 1, 2007
This and other information can be found on the Corps web site at:
httn://www.saw.usace.army.mil/WETLANDS/NWP2007/nationwide-pennits.html
24

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General State Stormwater Inspection Report
Project Name: Olsen Park Phase I
Permit No: SW8 090217
Expiration Date: new application
Contact Person: Jack Reel, PE, Thomas & Hutton, Brian Riley
Phone Number: 910-332-360
Inspection Type: pre -construction
Pre -permit
f Inspection Date: Thursday 5/7/09
Time In: 1:30 p.m.
Time Out: 2:30 p.m.
Current Weather: sunny, clear, 80 deg
Recent Rain (Date)? > week
Rain — in
Facility Address / Location: 6035 Murrayville Rd (SR 1322)
City: Wilmington Zi 28405 County: New
p' I Hanover Lat: 34 ° 17 ` 56 "N I Long: - 770 51 ` 58 "W
Permit Information
Rule Subject to (circle one): 2008 Coastal Rule 1995 Coastal Rule 2008 Coastal Rule Session Law 2006-246
C;SW Goose Creek High Quality Waters Outstanding Resource Waters
Density (circle one): High (HD) Low LD
Stormwater Best Management Practices (BMPs) (insert number of each): proposed
Wet Ponds Infiltration Basins Infiltration Trenches �C LD Swales Stormwater Wetlands
Dry Ponds Bioretention Permeable Pavement Sand filters (circle one) Open Closed
Cistern Level Spreader/Filter Strip Other (spec): _"diffuse at non -erosive velocity to vegetated areas"
File Review
1. Is the permit active?
� Ca
IYU
"/A
NIMX
2. Signed Engineer's Certification on file?
3. Signed Operation and Maintenance agreement on file? With permit qpplicadon
X
X
4. Recorded Deed Restrictions on file?
X
Site Visit: Ruilt Unnn Oraa IR1101
5. BUA is constructed and consistent with the permit requirements?
1 C,
IVU
tY/A
IV/C
6. BUA aspermitted) is graded such that the runoff drains to the system? (high density only)
X
X
7. Drainage area is consistent withpermit? i.e. no un ermitted drainage to the SW BMPs)
X
8. Drainage area is stabilized? to reduce risk of sedimentation to the SW BMPs
X
Site Visit: Stormwater BMPs
9. Stormwater BMPs are located per the app:
i0. Stormwater BMPs have dimensions eg. 1�
11. Stormwater BMPs are constructed per the
Site_ Visit• nnarafinn and Main4e..�nwe
the
Yes No NIA N/E
12. Access points to the site are clear and well maintained?
i VU
X
IVQ
IV/H
IV/t
13. Trash has been removed as needed?
X
14. Excessive landscape debris ass clippings, leaves, etc) is controlled?
15. Stormwater BMPs being operated and maintained as per the permit requirements?
X
X
16. Inspection and Maintenance records are available for inspection? (high density only, 1995 — only)
present
X
Site Visit: Other Permit Conditions Yes No NIA N/E
17. Is the site compliant with other conditions of the permit? I I —
Yes No NIA N/E
18. Is the site compliant with other water quality issues as noted during the inspections X
State Stornnwater Inspection Report, Version 3.0_3-09 Pagel of 2

State Stormwater Inspection Report
Pre -permit / Pre -construction site visit. Wetlands around the perimeter as delineated on plans.
Plans propose stormwater runoff to vegetated areas and flow spreaders prior to wetlands.
I
InsDectlon PICtU eS (some of the pictures taken during the site
OWNER:
City of Wilmington Parks and Rec
Compliance Status L1 Compliant ❑ Non -Compliant "NOT EVALUATED SINCE PRE PERMIT"
Letter Sent (circle one): Yes NO Letter type: CEI NOV NOVRE Other
Date Sent: n/a Reference Number: Incident # 200901129
Inspector Name and Signature:__%%%y , i%�Gs�/� Wr, Date:
State Stormwater Inspection Report, Version 3.0 3-09 Page 2 of 2

THOMAS & HUTTON ENGINEERING CO.
219 STATION ROAD
SUITE 101 CD MAP 6
WILMINGTON, NORTH CAROLINA 28405-3713
TELEPHONE [phone]
FAX I9101332-3361
Ira Hand Delivery
May 6, 2009)..�
Y -0
Ms. Mary Jean Naugle — 7
North Carolina Department of Environment and Natural Resources�'�..
Division of Water Quality+ .A
127 Cardinal Drive Extension
Wilmington, NC 28405
RE: Stormwater Resubmittal
Olsen Park
J-20050.303
Dear Ms. Naugle:
We are in receipt of your comments dated May 5, 2009 and on behalf of the City of Wilmington,
we offer the following in response:
1. Per your recommendation, the second page of the stormwater application has been revised to
include the future BUA. The allowable Proposed Impervious Area for the site was re -calculated
by multiplying 24% to the Total Drainage Area (3,893,129 sf). The revised Proposed Impervious
Area is 934,351 sf. Two copies of the revised 2"d page of the application are attached.
2. The BUA table on the Overall Site Plan Exhibit has been revised to match the stormwater
application. Future BUA has been added to the site data tables. Two copies of the revised exhibit
are attached and should replace the previously submitted copies in Section 2.5 of the storm water
report.
Please feel' free to contact me at [phone] should you have any questions or comments.
Thank you for your time and assistance with this project.
Sincerely,
THOMAS & HUTTON ENGINEERING CO.
Brian Riley
Project Manager
Enclosures: Revised Application (2"d page only)
Revised Overall Site Plan Exhibit
N:120050\Docs\Correspondence\NCDENR-Naugle-LT-response to comments 5-5-09.doc
SAVANNAH, GEORGIA • CHARLESTON, SOUTH CAROLINA • MYRTLE BEACH, SOUTH CAROLINA • BRUNSWICK, GEORGIA

SW8 090217 Olsen Park Additional Information Request
Subject: SW8 090217 Olsen Park Additional Information Request
From: Mary Jean Naugle <[e-mail]>
Date: Tue, 05 May 2009 15:57:50 -0400
To: "Reel, Jack" <reel [e-mail]>, "Riley, Brian" <[e-mail]>,
"Queen, Mickey" <[e-mail]>, Mary Naugle <[e-mail]>
Jack
Please update the 2nd page of the application to reflect the allocation for future
BUA to take the project to the 24 % density, as we discussed on the phone today?
i attached pg 2 with the mark ups, but it should come from the engineer with your
confirmation that this is ok.
i also attached a draft of the permit so that you can look at the impact in
sections I(1), II(10(f), and II(14).
Brian and Mickey;
i copied you in case you are taking care of this project. I thought Mickey, but
when i called today, the receptionist mentioned a fourth engineer ... so !
have a good one.
thank you for the information. Please provided within 30 days, but this one is
ready to issue with your confirmation and the page 2 mark ups.
Mary Jean Naugle
NC DENR Express Permitting
910-796-7303
910-350-2004 fax
Please note: E-mail correspondence to and from this address may be subject to the
North Carolina Public Records Law and may be disclosed to third parties.
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Content -Encoding: base64
090217 may09.doc Content -Type: application/msword
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n
" THOMAS & HUTTON ENGINEERING CO.
z
219 STATION ROAD
SUITE 101
WILMINGTON, NORTH CAROLINA 28405-3713
TELEPHONE [phone]
FAX [phone]
Via Hand Delivery
February 24, 2009
iREEC'D F E B 2 4 2009
Ms. Mary Jean Naugle
North Carolina Department of Environment and Natural Resources
Division of Water Quality
127 Cardinal Drive Extension
Wilmington, NC 28405
RE: Stormwater Resubmittal
Olsen Park
J-20050.303
Dear Ms. Naugle:
We are in receipt of your comments dated February 13, 2009 and on behalf of the City of
Wilmington, we offer the following in response:
1. An Overall Site Plan Exhibit (24"06") has been added to the Stormwater Design
Considerations Report in Section 2.5 that shows the property/permit line, BUA, wetlands
and other pertinent site information. The property/permit line includes bearing and
distances.
2. Two level spreaders have been added to the pipe outlets that drain to wetlands.
Alternatively, the swales that drain to the wetlands have been revised to follow the
contours upstream of the wetlands to facilitate non -erosive diffused flow. Referenced
Plan SheetC5 & C6.
3. The two pipe outlets (Pond 2 and Swale 1) that drain into the wetlands were designed
using the pond routing software described in Section 2.0 of the report. The 10-year
discharge rates and velocities for these pipes can be found in the "Node
Maximum/Minimum Report" in section 2.3 of the report.
4. Permissible Velocity calculations for the swales are provided in Section 4.1 of the report.
5. Two level spreaders have been added per response #2. See Section 4.3 of the report for
level spreader calculations.
6. The Level Spreader Supplement form is attached to this re -submittal.
7. See Section 4.3 of the report for level spreader calculations. The revised report is signed
and sealed.
8. One original of the O&M agreement for the level spreaders is attached.
N:\20050\Docs\Correspondence\NCDENR-Naugle-LT-response to comments.doc
SAVANNAH, GEORGIA • CHARLESTON, SOUTH CAROLINA • MYRTLE BEACH, SOUTH CAROLINA • BRUNSWICK, GEORGIA

Ms. Naugle
NCDENR
February 24, 2009
Page 2
Stormwater Management Permit Application
9. Two sets of the revised Stormwater Design Considerations Report are attached to the re -
submittal. The revised post development Exhibit E7 is included. The bound report is
signed and sealed.
10. The revised page 1 of the Low Density Supplement form is attached indicating the
correct BUA.
11. Sheet flow is utilized in all roads and parking lots as indicated by the road cross section
detail, centerline profiles, contours, and spot shots.
12. The connection pipes information were labeled on Sheet C15. The pipes were sized
using the Pond Routing Software in Section 2.0 of the report.
13. NOAA Atlas 14 rainfall data was used for this model and all supporting calculations. See
the revised calculations.
14. These are labeled in the results table in Section 3.2 of the report and pipe crossings are
labeled in the Post Development Exhibit. The stream crossings are designed to emulate
flow patterns in the existing ditch and to minimize adverse flooding conditions upstream
of the pipe crossings.
15. A copy of the 404 Certification is attached. As noted in the attached permit, a copy was
forwarded to the DWQ 401 Division.
16. The 50' vegetated buffer from the top bank of stream has been added and labeled to the
plans and "overall site plan".
Please feel free to contact me at [phone] should you have any questions or
comments. Thank you for your time and assistance with this project.
Sincerely,
THOMAS & HUTTON ENGINEERING CO.
J�k D. Reel, P.E.
Principal
JDR/kap
Enclosures: Revised Plans
Revised Low Density Supplement Form
Two copies of Revised Stormwater Report
Operation and Maintenance Agreement
404 Wetland Approval
N:\20050\Docs\Correspondence\NCDENR-Naugle-LT-response to comments.doc

Stormwater Application for Olsen Park
Subject: Stormwater Application for Olsen Park
From: Mary Jean Naugle <[e-mail]>
Date: Fri, 13 Feb 2009 19:54:29 -0500
To: [e-mail], reel [e-mail], Mary Naugle <[e-mail]>
Jack;
Please see the attached requirements to complete the application.
If you can address these by Feb 25, 2009, the package can be accepted.
If i don't receive the requested items by 2/25, then the application will be returned
as written.
These projects with large bua and close to streams, drainage ways, and wetlands are
challenging to meet the guidelines for low density. But this one looks like it can
meet the intent of diffuse flow to vegetated areas at non -erosive velocities if you
add the long swale on the low side following the contours with vegetation below and
add level spreaders on pipe crossings in the wetlands and streams.
Mary Jean Naugle
NC DENR Express Permitting
910-796-7303
910-350-2004 fax
Please note: E-mail correspondence to and from this address may be subject to the
North Carolina Public Records Law and may be disclosed to third parties.
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V Ah
_A14
NCDENR
North Carolina Department of Environment and Natural Resources
Division of Water Quality
Beverly Eaves Perdue Coleen H. Sullins Dee Freeman
Governor Director Secretary
February 13, 2009 q
Sterling Cheatham, City Manager l
City of Wilmington
102 North Third Street'
Wilmington, NC 28402
Subject: APPLICATION RETURN/
Project Name: Olsen Park — Phase 1 '
Location/County: New Hanover County
Dear Mr. Cheatham:
The Division received an incomplete stormwater application for the project listed above on February
4, 2009. The application and check number 254280, are being returned because the package lacked the
necessary elements to accept it for review. The following information is needed to accept the application for
review:
1. Provide one (1) site plan delineating boundaries for property lines, permit lines, built -upon area,
wetlands, streams and mitigation areas; on the same plan. Include bearings and distances for the
permit and property lines. Plans C9 and E7 appear to have some of the information but bearings
and distances are needed. Please provide two sets of plans. Please ensure that all permit area
and BUA is represented on the site plan. Several plans were provided with the required
information, but without the overall project on one plan, it is difficult to get a picture of the drainage
and permit areas with its impacts.
2. Provide stormwater outlets at diffuse flow and velocity less than 2 fps for the 10-year storm into
wetlands, surface waters, and mitigation areas. Provide level spreaders that follow the contours on
all stormwater outlets into vegetated areas. Alternatively, to provide diffuse flow at non -erosive
velocities, direct the swale and pipe outlets into long shallow swales that follow the contours
upstream of wetlands, with the down slope side slightly lower than the upstream side. The
proposed layout lends itself to this type of swale to provide diffuse flow at non -erosive velocities.
The proposed pipes and swales will channelize into the wetlands causing erosion.
3. Provide the design calculations on the pipe outlet into wetlands for the 10-year storm. The
proposed calculations for pipe outlets were provided for the 25 and 100-year storm, but these
outlets yield far greater than 2 fps.
4. Provide a maximum of 3.5 fps in other swales since the proposed permanent vegetation is grass
legume. [BMP 14].
5. Provide level spreaders for stormwater outlets on the pipe crossings into the wetlands and streams.
Provide a minimum of 13-foot lip level per 1 cfs. [BMP#8].
6. Provide the supplement for level spreaders.
7. Provide sealed design calculations for the level spreaders.
8. Provide a signed Operation and Maintenance Plan for the level spreaders.
9. Provide two sets of the drainage plans similar to that on plan # E7 in the calculations, with PE seal.
10. Provide consistent values for the proposed built -upon areas. The application, page 2, section 111 (8)
reports 262,231 square feet and the supplement page 2 reports 934,351 square feet.
11. Provide finished spot elevations on the BUA and roads to demonstrate runoff in a diffuse manner.
The goal of a low -density project is to provide sheet flow from BUA to vegetated areas, not to
collect in swales routed to a pond with one outlet from large areas.
Wilmington Regional Office
127 Cardinal Drive Extension, Wilmington, North Carolina 28405 One
Phone: [phone] FAX: [phone] Customer Service:1-877-623-6748 NorthCarolina
Internet: wwvr.ncwaterquality.org
Naturarlk
An Equal Opportunity 1 Affirmative Action Employer

12. If the two county retention ponds are connected, please provide information on the connecting pipe
size, inverts, etc...
13. Use NOOA website for rainfall intensities. The proposed calculations reported New Hanover
County Stormwater Manual.
14. Please verify what pipe velocities are reported on the "Culvert Report" in the proposed calculations?
The outlets significantly exceed the 3.5 — 5 fps for low -density projects. Provide numbers on the
table for each with labels on the plans.
15. Provide a copy of the cover letter for the 401 application for wetlands impacts and mitigation. The
stormwater permit cannot be issued until approval is received from the Division's 401 group.
16. Please remember that a change to one number may have a domino effect on other numbers.
Please check all plans, calculations, applications, supplements and other forms and make changes
as needed.
Please visit DWQ's website at http://h2o.enr.state.nc.us/su/bmp forms htm to download the latest
available forms and the application review checklist which is helpful in completing the package. Please
provide the requested information and return the package to the address below. If you have questions
please call me at [phone] or email me at [e-mail].
Sincerely,
U�Q qV�-
Mary can Naugle
GDS/min: S:1WQSISTORMWATERIRETURNIoisen pk ph 1 feb09
cc: Jack D. Reel, P.E., Thomas & Hutton Engineering Co., 910-332-3360, fax: 3361.
M.J. Naugle
DWQ files
Page 2 of 2

Project Name: E,ri YA ,1. Reviewer: Date:
Project Received Date: a Acce ted/Re'ec ed, circle one �;•: ;'
Project Location: N Add info required (yes/no), Date received:
Rule(s) Subject (check all that apply)y. Symbols for completing form: '✓'= Yes/OK• 'x'= No/Deficient 'n/a' A1
❑ 1995 Coastal 8' 2008 Coastal ❑ Phase II ❑ Universal
Paperwork: J�A l
❑ Check for $505 (must be no older than 6 months)
❑ Application form with correct/original signatures (original plus 1 copy). If Corporation or LLC also:
o Print the info from the NCSOS
o Either, 1.) The applicant is listed on the NCSOS with his/her correct title or, 2.) A notarized letter of
authorization has been provided:
❑ Supplements (1 original per BMP). BMP type(s):
❑ O&M with correctloriginal signatures (1 original per BMP, except level spreaders/filter strips and swales)
❑ Deed restrictions (if outparcel or subdividing) (original plus 1 copy)
o Deed restriction template (signed and notarized) or
o Proposed Declaration of Covenants and Restrictions (signed and notarized)
❑ Soils report identifying the SHWT
❑ Supporting calculations, signed & sealed (if necessary)
© Receiving stream classification: , If SA or ORW also:
o SA: USGS topo map with the site, the receiving waters and the mile radius shown to scale.
o ORW: 575 ft of MHWL for Area of Environmental Concern and max BUA per rule.
(3 Modifications: 1.) If built: Designer's Cert., 2.) If partially built: Partial Cert., 3.) If not built: No Cert. needed.
Development Type (check all that apply):
❑ Residential or 11 Commercial ❑ Deed restrictions match?
❑ Subdivision or ❑ Single Lot ❑ Deed restrictions match?
❑ I ligh Densi y or 13 Luvv Deilsiiy ❑ Deed restrictions matcn'r
Offsite project ❑ Redevelopme,nt ❑' Modification 1-'5 Exempt
1-1 NCG02 (bulkhead) ❑ NCG03 (clear/grade) F NCG04 (linear)
Density:
Q BUA calculations include common areas, clubhouse, sidewalks, etc.
BUA %: _ , Matches high/low density requirement for rule and receiving stream class.
❑ No obvious math errors
❑ If High Density: Design storm correct for rule and receiving stream class.
Plans, signed and aeale6 (2 sets): I IV
Two sets received ❑ Layout (with proposed BUA dimensions)
_,a;,Qrading Eal"brainage area map (all HD systems & curb outlet swales)
-EJ7_Vicinity map ❑ Project Boundaries ❑ Legend
-❑• Wetlands:
o Delineated on plans o "No wetlands onsite° on plans
Details:
o Roads o Cul-de-sacs o Curbing u Sidewalk
o BMNs/ Level spreaders/ Filter strips/ Curb outlet swales o Buildings (Apts. or Condos)
Offsite Projects:
® Designer's Certification has been submitted for the Offsite BMP receiving the runoff from the project.
❑ Deed restrictions have been recorded and a copy submitted for the Offsite BMP permit.
® Lot size has not changed from what was approved under the Master Plan.
❑ Correct lot number is referenced on the supplement form.
❑ Offsite system is in compliance with its permit, if known.
Infiltration Projects:
❑ Soils report: SHWT, soil type, and expected infiltration rate are provided.
❑ DWQ has conducted a site visit? Date:
Wet Ponds: Permanent Pool Meets One of the Following:
❑ Is located no lower than 6" below the estimated SHWT.
❑ Incoming groundwater is quantified and evaluated, AND Storage volume verified, AND Outlet evaluated for free
drainage to the receiving waters under SHWT conditions.
Decision (check one):
❑ Complete: Return file to admin (Jo Casmer) to log in. (Stamped in received date = BIMS date)
CSlightly incomplete: E-mail consultant, request information to be returned within one business day (24 hours after
1.7 request. Info requests on Friday, allow a return on the following business day). If info not returned, issue an
application return letter and give everything to admin. (Add info received date = BIMS date)
❑ Substantially incomplete: Issue an application return letter and give everything to admin.

T HOMAS & H UTTON ENGINEERING CO.
219 STATION ROAD
SUITE 101
WILMINGTON, NORTH CAROLINA 28405-3713
TELEPHONE [phone]
FAX [phone]
Via bland Delivery
February 3, 2009
ctf
Ms. Jo Casmer 4 200
North Carolina Department of Environment and Natural Resources
Division of Water Quality
127 Cardinal Drive Extension
Wilmington, NC 28405
RE: Stormwater Permit Application
Olsen Park — Phase 1
New Hanover County
J-20050.303
Dear Ms. Casmer:
On behalf of the City of Wilmington, we are pleased to submit the Stormwater
Management Permit Application for the above referenced project. The following items are
included for your review:
• Permit application processing fee of $505.00, Check No. 254280;
• Original and one (1) copy of the completed Stormwater Management Application Form;
• One (1) original of the Low Density SW401 Supplement Form;
• One (1) copy of the Letter of Appointment as Agent to City of Wilmington;
• One (1) copy of Stormwater and Erosion Control Desig: Considerations including
Project Narrative and Vicinity Map;
• Two (2) copies of the Stormwater and Erosion Control Specifications;
• Two (2) copies of Site Development Plans.
B®0 4 2009
N:\20050\Docs\Correspondence\NCDENR-Casmer-LT-Submittal(SW) 02-03-09.docx
SAVANNAH, GEORGIA • CHARLESTON, SOUTH CAROLINA • MYRTLE BEACH, SOUTH CAROLINA • BRUNSWICK, GEORGIA

Ms. Jo Casmer
NCDENR
February 3, 2009
Page 2
Stormwater Management Permit Application
Please review the application, and if everything is in order, we respectfully request
NC;DENR approval. Please feel free to contact n:e at [phone] should you Have any
questions or comments. Thank you for your time and assistance with this project.
Sincerely,
THOMAS & HUTTON ENGINEERING CO.
?'A L
JalkA,,. Reel, P.E.
Manager
JDR/rjf
Enclosures: As listed above
cc: Tara Duckworth, John Rancke (City of Wilmington); Sara Burroughs (Haden Stanziale, P.A.)
N:\20050\Docs\Correspondence\NCDENR-Casmer-LT-Submittal(SW) 02-03-09.docx

New Hanover County
14ORTH*CAROLINA
To:
From:
Subject:
Date:
New Hanover County Parks Department
MEMO
NCDNER
Bruce Shell, County Manager! Neal Lewis, Parks Director
Olson Farm Park property
January 8, 2009
Tax Map Number.
R03400-002-003.001
Property Name:
New Hanover County (Olsen Farm Park)
Property Location:
Corporate Drive
Property Owner
New Hanover County
230 Government Center Drive
Wilmington, NC 28403
BY:
FED 0 4 2009
In connection with the above references! property, I herby appoint the person shown below as agent for the purpose of
filing such applications for project approval as they deem necessary and proper.
Authorized Agent: City of Wilmington, Sterling Cheatham, City Manager
PO Box 1810
Wilmington, NC 28401
Telephone: [phone]
Reason: Development of Park property
X IS, I . 1), X --,,; -:1'77
Witness Bruce Shell
Cosulty Manager
NEW HANOVER COUNTY PARKS DEPARTMENT 230 GOVERNMENT CENTER DRIVE WILMINGTON, NC 28403
(910YJ98-7620 [phone] FAX &Mail: ftkI alwaw.opm