SW6170901 - Oak Hill Living Center (4)

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OAK HILL
LIVING CE'NTE'R
9767 NC 210
ANGIER, NORTH CAROLINA
STORMWATER CALCULATIONS
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DATE: 11 JULY 2017
REVISED: 24 AUGUST 2017
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COPYRIGHT © 2017 BOBBITT DESIGN -BUILD, INC ALL RIGHTS RESERVED
600 GERMANTOWN ROAD
RALEIGH NC 27607
TELEPHONE [phone]
FAX [phone]

GENERAL DESCRIPTION
This project is located in the Town of Angier near the intersection of N Pleasant St and NC 210.
(PIN# 0684-00-8362.000). The property is currently developed as an assisted living facility. The
site is 12.46 acres, of which this project will re -develop approximately 2.06 acres into additional
living space and improved parking.
This is a low-density project in a Phase II Area and is subject to Stormwater regulations. Per
these regulations this project must have a built upon area of less than 24%, maximize disperse
flow, and use vegetated conveyances where disperse flow is not feasible. While the overall site is
low-density, the sub -drainage basin where the project is located exceeds 24% built upon area and
is subject to the regulations for high density projects. Per these regulations this portion of the
project must achieve runoff treatment by utilizing one Primary SCM to treat new impervious
run-off. The proposed design captures the majority of the proposed impervious areas and routes
run-off through a bioretention cell. After review of the 1 -year, 10 -year, and 25 -year run-off
models of the pre- and post -development conditions it was determined that detention of the
stormwater run-off is required for the post -development runoff so that the required storms do not
exceed the pre -development conditions.
Slopes in the developed areas of the site are approximately 2-3% and slopes along the periphery
are 4:1-3:1. USDA soil maps identify the following soil types on the site:
DoB — Dothan loamy sand (2-6% slope) HSG: B
FaB — Fuquay loamy sand (0-6% slope) HSG: B
Ly — Lynchburg sandy loam (0-2% slope) HSG: B/D
The site is located in the Cape Fear River Basin, and according to FEMA flood maps and Flood
Insurance Study, there are no floodways orfloodplains present on the property.
METHODOLOGY
This study used Hydraflow Hydrographs software that can model a variety of watersheds with
variations. The software allows for hydrologic analyses using several different methods
including the Rational and USDA NRSS TR -55 methods. This study used the standard rational
method to model the peak 1-, 10-, and 25 -yr rainfall events.
TREATMENT PROCESS
In compliance with 15A NCAC 02H.1003(3), the development will construct a bioretention cell
for the stormwater leaving the site. The stormwater will sheet flow over the paved areas and
collect in either a storm network or swale. The network and swale will discharge to a concrete
fore -bay in the bioretention pond. The collected stormwater from the proposed bioretention will
infiltrate through the soil media and into a subgrade collection network. This network is
connected to a riser flow control structure and will discharge through a flared end section with
rip -rap protection.

DRAINAGE AREA RUN-OFF SUMMARY

Drainage Area Run-off Summary —
Oak Hill Livinm Center - 9 76 7 NC 210, Ander, NC
At the time of this development, 9767 NC 210 has been developed as an assisted living
facility. The property is located toward the top of a drainage basin with three sub -
drainage basins. Run-off flowing west is split by an existing ridge resulting in 2 sub -
drainage basins. A third portion of the site drains east to a small pond on the adjacent
property. A portion of the on-site runoff is captured in an existing dry detention basin and
released to grade. The existing dry -detention basin is modeled based on field surveyed
topography. All sub -drainage basins ultimately drain to nearby Black River.
In predevelopment conditions, 4.93 acres of the site drains northwest to the adjacent
property (Drainage Area 1). 0.34 acres drains east to the existing pond (Drainage Area
2). 7.19 acres drain southwest to the adjacent property (Drainage Area 3). Approximately
1.97 acres in Drainage Area 3 drains to the existing dry -detention pond.
Post -development conditions will increase the size of Drainage Area 1 to 4.98 acres, of
which 1.82 acres will drain to a bioretention cell. The bioretention cell is a primary
Stormwater Control Measure (SCM) per NCDEQ MDC and is proposed for stormwater
quantity and quality control. It has been sized for extended detention and will provide
85% TSS removal as well as nutrient removal. In the post -development condition, the
bioretention will serve most of the proposed project impervious area. Drainage Area 2 is
reduced to 0.29 acres as part of this project. The drainage areas for Drainage Area 3 is not
changed as part of this project. However, the impervious area in Drainage Area 3 is
increased as part of this project, but this increase is minimal, and does not noticeably
increase the runoff coefficient in the drainage area.
Per the TR55 method, the time of concentration (Tc) for pre -development conditions in
Drainage Area 1 is +/-4 minutes and in post -development conditions the Tc is +/- 3
minutes. A minimum Tc of 5 minutes is used for calculating peak flow. Tc for Drainage
Area 3 is +/- 5 minutes. Please see attached TR55 worksheets for calculations.
Proposed Coefficient (C -Values)
C (open space, graded, and landscaped) = 0.35
Q(impervious) = 0.95
Total DA 1 PRE -development = 4.93 Acres
Total DA 1 POST -development = 4.98 Acres
DA I POST -development = 1.82 Acres (Routed through Bioretention)
DA 1B POST -development = 3.16 Acres (By-pass Bioretention)
Total DA 2 PRE -development = 0.34 Acres
Total DA 2 POST -development = 0.29 Acres
Total DA 3 PRE- and POST- development = 7.19 Acres

DA 3A PRE- and POST -development = 1.97 Acres (Routed through Ex. Dry -Pond)
DA 3B PRE- and POST -development = 5.22 Acres (By-pass Ex. Dry -Pond)
Drainage Areas (1 yr. Rational method)
I - (1 yr) = 4.48 in/hr (Tc-5min.)
Drainage Area 1 MAI)
Pre -Development -
0.45 (C -Value) x 4.48 x 12.12 ac = 24.43 cfs
Post -Development -
On -Site: 1.82 ac Routed through Bioretention = 0.08 cfs
On -Site By-pass: 0.46 (C -Value) x 4.48 x 10.35 ac = 21.33 cfs
Peak Combined Flows: - 21.37 cfs (Post<=Pre)
Drainage Area 2 (DA2)
Pre -Development -
Post -Development -
Drainage Area 3 (DA3)
Pre- and Post -Development -
On -Site:
On -Site By-pass:
0.35 (C -Value) x 4.48 x 0.34 ac =
0.35 (C -Value) x 4.48 x 0.29 ac =
1.97 ac Routed through Ex. Dry Pond =
0.40 (C -Value) x 4.48 x 5.22 ac =
Peak Combined Flows:
Drainage Areas (10 yr. Rational method)
I - (10 yr) = 7.22 in/hr (Tc-5min.)
Drainage Area 1 MAU
Pre -Development -
0.45 (C -Value) x 7.22 x 12.12 ac =
0.53 cfs
0.45 cfs (Post<=Pre)
0.88 cfs
9.35 cfs
10.15 cfs
39.38 cfs
Post -Development -
On -Site: 1.82 ac Routed through Bioretention = 0.12 cfs
On -Site By-pass: 0.46 (C -Value) x 7.22 x 10.35 ac = 34.37 cfs
Peak Combined Flows: 34.42 cfs (Post<=Pre)

Drainage Area 2 (DA2)
Pre -Development -
Post -Development -
Drainage Area 3 (DA3)
Pre- and Post -Development -
On -Site:
On -Site By-pass:
0.35 (C -Value) x 7.22 x 0.34 ac =
0.35 (C -Value) x 7.22 x 0.29 ac =
1.97 ac Routed through Ex. Dry Pond =
0.40 (C -Value) x 7.22 x 5.22 ac =
Peak Combined Flows:
Drainage Areas (25 yr. Rational method)
I - (25 yr) = 8.19 in/hr (Tc-5min.)
Drainage Area 1 (DA1)
Pre -Development -
0.45 (C -Value) x 8.19 x 12.12 ac =
0.86 cfs
0.73 cfs (Post<=Pre)
0.99 cfs
15.07 cfs
15.93 cfs
44.67 cfs
Post -Development -
On -Site: 1.82 ac Routed through Bioretention = 0.14 cfs
On -Site By-pass: 0.46 (C -Value) x 8.19 x 10.35 ac = 39.00 cfs
Peak Combined Flows: 39.08 cfs (Post<=Pre)
Drainage Area 2 (DA2)
Pre -Development -
Post -Development -
Drainage Area 3 (DA3)
Pre- and Post -Development -
On -Site:
On -Site By-pass:
0.35 (C -Value) x 8.19 x 0.34 ac =
0.35 (C -Value) x 8.19 x 0.29 ac =
1.97 ac Routed through Ex. Dry Pond =
0.40 (C -Value) x 8.19 x 5.22 ac =
0.98 cfs
0.83 cfs (Post<=Pre)
1.03 cfs
17.10 cfs
Peak Combined Flows: 17.99 cfs

Watershed Model Schematic HydraflowHydrographs Extension for AutoCADO Civil 3DO2016 by Autodesk, Inc. v10.514
10L 31
V- 6
Legend
JW&L Origin
1
Rational
DA 1 - PRE -DEVELOPMENT
2
Rational
DA 1 - POST -DEVELOPMENT - TO POND
3
Reservoir
BIORETENTION POND
4
Rational
DA 1 - POST -DEVELOPMENT- BY-PASS POND
5
Combine
DA 1 - POST -DEVELOPMENT WITH CONTROL
6
Combine
DA 1 - POST DEVELOPMENT - NO CONTROL
7
Rational
DA 2 - PRE -DEVELOPMENT
8
Rational
DA 2 - POST -DEVELOPMENT
9
Rational
DA 3 -PRE- & POST -DEVELOPMENT - TO POND
10
Reservoir
Ex. Dry Pond
11
Rational
DA 3 - PRE- & POST -DEVELOPMENT - BY-PASS POND
12
Combine
DA 3 - TOTAL PRE -DEVELOPMENT
Project: BioRetention.gpw
Wednesday, 07 / 12 / 2017

Pond Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.514 Wednesday, 07 / 12 / 2017
Pond No. 1 - Bioretention Pond 1
Pond Data
Contours -User-defined contour areas. Conic method used for volume calculation. Begtning Elevation = 314.00 ft
Stage / Storage Table
Stage (ft) Elevation (ft) Contour area (sgft) Incr. Storage (cult) Total storage (cuft)
0.00 314.00 3,094 0 0
1.00 315.00 3,780 3,431 3,431
2.00 316.00 4,528 4,148 7,579
2.50 316.50 5,907 2,601 10,180
Culvert / Orifice Structures
Weir Structures
[A]
[B]
[C]
[PrFRsr]
[A]
[B]
[C]
[D]_
Rise (in)
= 15.00
Inactive
Inactive
Inactive
Crest Len (ft)
= 8.00
10.00
0.00
0.00
Span (in)
= 15.00
0.00
0.00
0.00
Crest EI. (ft)
= 315.00
315.50
0.00
0.00
No. Barrels
= 1
1
1
1
Weir Coeff.
= 3.33
2.60
3.33
3.33
Invert EI. (ft)
= 311.31
0.00
0.00
0.00
Weir Type
= 1
Broad
-
-
Length (ft)
= 26.00
0.00
0.00
0.00
Multi -Stage
= Yes
No
No
No
Slope (%)
= 1.00
0.00
0.00
n/a
N -Value
= .013
.013
.013
n/a
Orifice Coeff.
= 0.60
0.60
0.60
0.60
ExTil.(In/hr)
= 2.000 (by
Contour)
Multi -Stage
= n/a
No
No
No
TW Elev. (ft)
= 0.00
Stage (ft)
3.00
2.00
1.00
0.00 '
0.00 4.00
Total Q
Note Culvert/Onfice outflows are analyzed under inlet (ic) and outlet (Go) control Weir risers checked for onfice conditions (tc) and submergence (s).
Stage / Discharge
8.00 12.00 16.00 20.00 24.00 28.00 32.00 36.00
Elev (ft)
317.00
316.00
315.00
---1- 314.00
40.00
Discharge (cfs)

Ponca Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3DO 2016 by Autodesk, Inc. v10.514
Wednesday, 07 ! 12 / 2017
Pond No. 2 - Ex. Dry Pond
Pond Data
Contours -User-defined contour areas. Conic method used for volume calculation. Beglning
Elevation = 309.00 ft
Stage / Storage Table
Stage (ft) Elevation (ft)
Contour area (sgft)
Incr. Storage (cuft)
Total storage (cuft)
0.00 309.00
00
0
0
1.00 310.00
1,781
594
594
2.00 311.00
5,975
3,672
4,266
3.00 312.00
10,346
8,060
12,326
3.50 312.50
7,390
4,413
16,739
4.00 313.00
15,054
5,498
22,237
4.50 313.50
16,891
7,981
30,218
Culvert / Orifice Structures
Weir Structures
[A]
[B] [C]
[PrfRsr]
[A] [B]
[C] [D]
Rise (in) = 18.00
6.00 0.00
0.00
Crest Len (ft)
= 9.00 15.00
0.00 0.00
Span (in) = 18.00
6.00 0.00
0.00
Crest EI. (ft)
= 312.50 312.50
0.00 0.00
No. Barrels = 1
1 0
0
Weir Coeff.
= 3.33 3.33
3.33 3.33
Invert EI. (ft) = 309.00
309.07 0.00
0.00
Weir Type
= 1 Cipltt
- -
Length (ft) = 50.00
0.00 0.00
0.00
Multi -Stage
= Yes No
No No
Slope (%) = 2.78
0.00 0.00
n/a
N -Value = .013
.013 .013
n/a
Orifice Coeff. = 0.60
0.60 0.60
0.60
Exfil.(inlhr)
= 0.000 (by Wet area)
Multi -Stage = n/a
No No
No
TW Elev. (ft)
= 0.00
Note CulvertlOnfice outflows are analyzed under inlet (ic) and outlet (oc) control Weir risers checked for onfice conddions (ic) and submergence (s)
Stage (ft)
5.00
4.00
3.00
P410I01
1.00
0.00 ' '
0.00 7.00
Total Q
Stage / Discharge
14.00 21.00 28.00 35.00 42.00 49.00 56.00 63.00
Elev (ft)
314.00
313.00
312.00
311.00
310.00
1 309.00
70.00
Discharge (cfs)

1 FEAR ST®RM

Hydrograph S u m m a ry Rep® qydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc v10.514
Hyd.
No.
Hydrograph
type
(origin)
Peak
flow
(cfs)
Time
interval
(min)
Time to
Peak
(min)
Hyd.
volume
(cult)
Inflow
hyd(s)
Maximum
elevation
(ft)
Total
strge used
(cult)
Hydrograph
Description
1
Rational
9.939
1
5
2,982
---
--
--
DA 1 - PRE -DEVELOPMENT
2
Rational
5 137
1
5
1,541
-----
---
---
DA 1 - POST -DEVELOPMENT - TO
3
Reservoir
0.077
1
10
1,521
2
314.44
1,518
BIORETENTION POND
4
Rational
6.087
1
5
1,826
---
-----
---
DA 1 - POST -DEVELOPMENT - BY -
5
Combine
6 127
1
5
3,348
3,4
-----
—
DA 1 - POST -DEVELOPMENT WITH
6
Combine
11 22
1
5
3,367
2, 4,
----
---
DA 1 - POST DEVELOPMENT - NO
7
Rational
0.533
1
5
160
---
--
--
DA 2 - PRE -DEVELOPMENT
8
Rational
0.455
1
5
136
--
----
DA 2 - POST -DEVELOPMENT
9
Rational
5.295
1
5
1,589
---
--
--
DA 3 -PRE- & POST-DEVELOPMEN
10
Reservoir
0.878
1
9
1,568
9
31018
1,266
Ex. Dry Pond
11
Rational
9.354
1
5
2,806
---
----
----
DA 3 - PRE- & POST-DEVELOPMEN
12
Combine
10.15
1
5
4,374
10,11
-----
----
DA 3 - TOTAL PRE -DEVELOPMENT
BioRetention.gpw
Return Period: 1 Year
Wednesday, 07 / 12 / 2017

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3138 2016 by Autodesk, Inc. A 0.514 Wednesday, 07 / 12 12017
Hyd. No. 1
DA 1 - PRE -DEVELOPMENT
Hydrograph type
= Rational
Peak discharge
= 9.939 cfs
Storm frequency
= 1 yrs
Time to peak
= 5 min
Time interval
= 1 min
Hyd. volume
= 2,982 cuft
Drainage area
= 4.930 ac
Runoff coeff.
= 0.45
Intensity
= 4.480 in/hr
Tc by User
= 5.00 min
IDF Curve
= mid_NC_1yr.IDF
Asc/Rec limb fact
= 1/1
Q (cfs)
10.00
,;M
. la
4.00
2.00
0.00 le '
0 1
Hyd No. 1
DA 1 - PRE -DEVELOPMENT
Hyd. No. 1 —1 Year
2 3 4 5 6 7 8 9
Q (cfs)
10.00
8.00
4.00
2.00
3 0.00
10
Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D@2016 by Autodesk, Inc. v10.514 Wednesday, 07 / 12 / 2017
Hyd. No. 2
DA 1 - POST -DEVELOPMENT - TO POND
Hydrograph type
= Rational
Peak discharge
= 5.137 cfs
Storm frequency
= 1 yrs
Time to peak
= 5 min
Time interval
= 1 min
Hyd. volume
= 1,541 cuff
Drainage area
= 1.820 ac
Runoff coeff.
= 0.63
Intensity
= 4.480 in/hr
Tc by User
= 5.00 min
IDF Curve
= mid_NC_1yr.IDF
Asc/Rec limb fact
= 1/1
Q (cfs)
6.00
5.00
4.00
3.00
2.00
1.00
DA 1 - POST -DEVELOPMENT - TO POND
Hyd. No. 2 —1 Year
Q (cfs)
6.00
5.00
4.00
3.00
2.00
1.00
0.00 vI I I I I I I I I N 0.00
0 1 2 3 4 5 6 7 8 9 10
Hyd No. 2 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.514
Hyd. No. 3
BIORETENTION POND
Hydrograph type
= Reservoir
Peak discharge
Storm frequency
= 1 yrs
Time to peak
Time interval
= 1 min
Hyd. volume
Inflow hyd. No.
= 2 - DA 1 - POST-DEVELOPMBM -. 1119VAUN D
Reservoir name
= Bioretention Pond 1
Max. Storage
Storage Indication method used. Outflow includes exfiltration.
Q (cfs)
6.00
5.00
4.00
3.00
2.00
1.00
0.00
0 120 240
Hyd No. 3
BIORETENTION POND
Hyd. No. 3 —1 Year
360 480 600
Hyd No. 2
Wednesday, 07 / 12 / 2017
= 0.077 cfs
= 10 min
= 1,521 cuft
= 314.44 ft
= 1,518 cuft
Q (cfs)
6.00
5.00
4.00
3.00
2.00
1.00
0.00
720 840 960 1080 1200 1320 1440
® Total storage used = 1,518 cult Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3138 2016 by Autodesk, Inc. v10.514 Wednesday, 07 112 / 2017
Hyd. No. 4
DA 1 - POST -DEVELOPMENT - BY-PASS POND
Hydrograph type
= Rational
Peak discharge
= 6.087 cfs
Storm frequency
= 1 yrs
Time to peak
= 5 min
Time interval
, = 1 min
Hyd. volume
= 1,826 cuft
Drainage area
= 3.160 ac
Runoff coeff.
= 0.43
Intensity
= 4.480 in/hr
Tc by User
= 5.00 min
IDF Curve
= mid_NC_1yr.IDF
Asc/Rec limb fact
= 1/1
DA 1 - POST -DEVELOPMENT - BY-PASS POND
Q (cfs) Hyd. No. 4 —1 Year
7.00
6.00
5.00
4.00
3.00
2.00
1.00
000
0 1 2
Hyd No. 4
Q (cfs)
7.00
6.00
5.00
4.00
3.00
2.00
1.00
0.00
3 4 5 6 7 8 9 10
Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.514
Wednesday, 07 / 12 / 2017
Hyd. No. 5
DA 1 - POST -DEVELOPMENT WITH CONTROL
Hydrograph type
= Combine
Peak discharge
= 6.127 cfs
Storm frequency
= 1 yrs
Time to peak
= 5 min
Time interval
= 1 min
Hyd. volume
= 3,348 cuft
Inflow hyds.
= 3, 4
Contrib. drain. area
= 3.160 ac
DA 1 - POST -DEVELOPMENT WITH CONTROL
Q (cfs) Hyd. No. 5 —1 Year
7.00
6.00
5.00
4.00
3.00
2.00
1.00
000
0 10
Hyd No. 5
20 30 40 50 60
Hyd No. 3 Hyd No. 4
Q (cfs)
7.00
6.00
5.00
4.00
3.00
2.00
1.00
0.00
70 80 90
Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 31382016 by Autodesk, Inc. 00.514 Wednesday, 07 / 12 / 2017
Hyd. No. 6
DA 1 - POST DEVELOPMENT - NO CONTROL
Hydrograph type = Combine Peak discharge = 11.22 cfs
Storm frequency = 1 yrs Time to peak = 5 min
Time interval = 1 min Hyd. volume = 3,367 cuft
Inflow hyds. = 2, 4 Contrib. drain. area = 4.980 ac
Q (cfs)
12.00
10.00
8.00
W9
4.00
"I
0.00 -M I'
0 1 2
Hyd No. 6
DA 1 - POST DEVELOPMENT - NO CONTROL
Hyd. No. 6 —1 Year
3 4
Hyd No. 2
5 6 7
Hyd No. 4
8 9
Q (cfs)
12.00
10.00
8.00
M
4.00
2.00
0.00
10
Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.514
Hyd. No. 7
DA 2 - PRE -DEVELOPMENT -
Hydrograph type
= Rational
Peak discharge
Storm frequency
= 1 yrs
Time to peak
Time interval
= 1 min
Hyd. volume
Drainage area
= 0.340 ac
Runoff coeff.
Intensity
= 4.480 in/hr
Tc by User
IDF Curve
= mid_NC_1yr.IDF
Asc/Rec limb fact
DA 2 - PRE -DEVELOPMENT
Q (cfs) Hyd. No. 7 —1 Year
1.00
0.90
0.80
0.70
0.60
0.50--
0.40-
0.30
.500.400.30
0.20
0.10
000
Wednesday, 07 / 12 / 2017
= 0.533 cfs
= 5 min
= 160 cuft
= 0.35
= 5.00 min
= 1/1
Q (cfs)
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0 00
0 1 2 3 4 5 6 7 8 9 10
Hyd No. 7
Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. A 0.514 Wednesday, 07 / 12 / 2017
Hyd. No. 8
DA 2 - POST -DEVELOPMENT
Hydrograph type
= Rational
Peak discharge
= 0.455 cfs
Storm frequency
= 1 yrs
Time to peak
= 5 min
Time interval
= 1 min
Hyd. volume
= 136 cuft
Drainage area
= 0.290 ac
Runoff coeff.
= 0.35
Intensity
= 4.480 in/hr
Tc by User
= 5.00 min
IDF Curve
= mid_NC_1yr.IDF
Asc/Rec limb fact
= 1/1
Q (cfs)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
000
DA 2 - POST -DEVELOPMENT
Hyd. No. 8 —1 Year
0 1 2 3 4 5 6
Hyd No. 8
Q (cfs)
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
7 8 9 10
Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. 00.514 Wednesday, 07 / 12 / 2017
Hyd. No. 9
DA 3 -PRE- & POST -DEVELOPMENT - TO POND
Hydrograph type
= Rational
Peak discharge
= 5.295 cfs
Storm frequency
= 1 yrs
Time to peak
= 5 min
Time interval
= 1 min
Hyd. volume
= 1,589 cuft
Drainage area
= 1.970 ac
Runoff coeff.
= 0.6
Intensity
= 4.480 in/hr
Tc by User
= 5.00 min
IDF Curve
= mid_NC_1yr.IDF
Asc/Rec limb fact
= 1/1
Q (cfs)
6.00
5.00
4.00
3.00
2.00
1.00
DA 3 -PRE- & POST -DEVELOPMENT - TO POND
Hyd. No. 9 —1 Year
Q (cfs)
6.00
5.00
4.00
3.00
2.00
1.00
0.00 11 1 1 1 1 1 1 1 1 1 v 0.00
0 1 2 3 4 5 6 7 8 9 10
Hyd No. 9 Time (min)

Hydrograph: Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3130 2016 by Autodesk, Inc. v10.514
Wednesday, 07 / 12 / 2017
Hyd. No. 10
Ex. Dry Pond
Hydrograph type
= Reservoir
Peak discharge =
0.878 cfs
Storm frequency
= 1 yrs
Time to peak =
9 min
Time interval
= 1 min
Hyd. volume =
1,568 cuft
Inflow hyd. No.
= 9 - DA 3 -PRE- & POST-DEVEWFIEiIU660 POND=
310.18 ft
Reservoir name
= Ex. Dry Pond
Max. Storage =
1,266 cuft
Storage Indication method used.
Q (cfs)
6.00
5.00
4.00
43M
2.00
MIA
0.00 —
0 10
Hyd No. 10
Ex. Dry Pond
Hyd. No. 10 —1 Year
20 30 40 50 60 70 80
Hyd No. 9 ® Total storage used = 1,266 cuft
Q (cfs)
6.00
5.00
4.00
3.00
2.00
1.00
--� 0.00
90
Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.514
Hyd. No. 11
DA 3 - PRE- & POST -DEVELOPMENT - BY-PASS POND
Hydrograph type
= Rational
Peak discharge
Storm frequency
= 1 yrs
Time to peak
Time interval
= 1 min
Hyd. volume
Drainage area
= 5.220 ac
Runoff coeff.
Intensity
= 4.480 in/hr
Tc by User
IDF Curve
= mid_NC_1yr.IDF
Asc/Rec limb fact
Q (cfs)
10.00
8.00
go
4.00
2.00
0.00 K '
0 1
Hyd No. 11
DA 3 - PRE- & POST -DEVELOPMENT - BY-PASS POND
Hyd. No. 11 —1 Year
Wednesday, 07 / 12 / 2017
= 9.354 cfs
= 5 min
= 2,806 cuft
= 0.4
= 5.00 min
= 1/1
2 3 4 5 6 7 8 9
Q (cfs)
10.00
we
"M
4.00
2.00
- 1 0.00
10
Time (min)

Hy►drograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.514
Hyd. No. 12
DA 3 - TOTAL PRE -DEVELOPMENT
Hydrograph type
= Combine
Peak discharge
Storm frequency
= 1 yrs
Time to peak
Time interval
= 1 min
Hyd. volume
Inflow hyds.
= 10, 11
Contrib. drain. area
Q (cf
12.00
10.00
8.00
. �a
4.00
r K9
DA 3 - TOTAL PRE -DEVELOPMENT
s) Hyd. No. 12 --1 Year
,AAi
Wednesday, 07 / 12 / 2017
= 10.15 cfs
= 5 min
= 4,374 cuft
= 5.220 ac
Q (cfs)
12.00
10.00
8.00
M
4.00
Wiff
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44
Hyd No. 12 Hyd No. 10 Hyd No. 11 Time (min)

10 YEAR STORM

Hydrograph Summary Repo qydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc v10 514
Hyd.
No.
Hydrograph
type
(origin)
Peak
flow
(cfs)
Time
interval
(min)
Time to
Peak
(min)
Hyd.
volume
(cult)
Inflow
hyd(s)
Maximum
elevation
(ft)
Total
strge used
(cuft)
Hydrograph
Description
1
Rational
16.01
1
5
4,803
---
--
--
DA 1 - PRE -DEVELOPMENT
2
Rational
8.274
1
5
2,482
---
---
----
DA 1 - POST -DEVELOPMENT - TO
3
Reservoir
0.125
1
10
2,463
2
314.71
2,445
BIORETENTION POND
4
Rational
9.805
1
5
2,942
--
--
DA 1 - POST -DEVELOPMENT - BY -
5
Combine
9.868
1
5
5,404
3,4
--
—
DA 1 - POST -DEVELOPMENT WITH
6
Combine
1808
1
5
5,424
2, 4,
---
-----
DA 1 - POST DEVELOPMENT - NO
7
Rational
0.859
1
5
258
----
--
---
DA 2 - PRE -DEVELOPMENT
8
Rational
0 732
1
5
220
--
--
DA 2 - POST -DEVELOPMENT
9
Rational
8.529
1
5
2,559
---
--
DA 3 -PRE- & POST-DEVELOPMEN
10
Reservoir
0.994
1
9
2,538
9
310.43
2,159
Ex. Dry Pond
11
Rational
1507
1
5
4,520
---
--
----
DA 3 - PRE- & POST-DEVELOPMEN
12
Combine
15.93
1
5
7,058
10,11
--
---
DA 3 - TOTAL PRE -DEVELOPMENT
BioRetention.gpw
Return Period: 10 Year
Wednesday, 07 / 12 / 2017

L
Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.514 Wednesday, 07 / 12 / 2017
Hyd. No. 1
DA 1 - PRE -DEVELOPMENT
Hydrograph type
= Rational
Peak discharge
= 16.01 cfs
Storm frequency
= 10 yrs
Time to peak
= 5 min
Time interval
= 1 min
Hyd. volume
= 4,803 cuft
Drainage area
= 4.930 ac
Runoff coeff.
= 0.45
Intensity
= 7.216 in/hr
Tc by User
= 5.00 min
IDF Curve
= mid_NC_1yr.IDF
Asc/Rec limb fact
= 1/1
Q (cfs)
18.00
15.00
12.00
9.00
6.00
3.00
DA 1 - PRE -DEVELOPMENT
Hyd. No. 1 —10 Year
Q (cfs)
18.00
15.00
12.00
M
6.00
3.00
0.00 -Y ' ' ' ' ' ' ' ' ' N 0.00
0 1 2 3 4 5 6 7 8 9 10
Hyd No. 1 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.514 Wednesday, 07 / 12 / 2017
Hyd. No. 2
DA 1 - POST -DEVELOPMENT - TO POND
Hydrograph type
= Rational
Peak discharge
= 8.274 cfs
Storm frequency
= 10 yrs
Time to peak
= 5 min
Time interval
= 1 min
Hyd. volume
= 2,482 cuft
Drainage area
= 1.820 ac
Runoff coeff.
= 0.63
Intensity
= 7.216 in/hr
Tc by User
= 5.00 min
IDF Curve
= mid_NC_1yr.IDF
Asc/Rec limb fact
= 1/1
Q (cfs)
10.00
8.00
mm
4.00
2.00
0.00 If '
0 1
Hyd No. 2
DA 1 - POST -DEVELOPMENT - TO POND
Hyd. No. 2 —10 Year
2 3 4 5\ 6 7 8 9
Q (cfs)
10.00
8.00
. W
4.00
2.00
—1 0.00
10
Time (min)

Hydrograflph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3DO 2016 by Autodesk, Inc. v10.514
Hyd. No. 3
BIORETENTION POND
Hydrograph type
= Reservoir
Peak discharge
Stomp frequency
= 10 yrs
Time to peak
Time interval
= 1 min
Hyd. volume
Inflow hyd. No.
= 2 - DA 1 - POST-DEVELOPMBRTx- 1EI9%@QN D
Reservoir name
= Bioretention Pond 1
Max. Storage
Storage Indication method used. Outflow includes exit tration.
Q (cfs)
10.00
M
wo
4.00
2.00
0.00'
0 120 240
Hyd No. 3
BIORETENTION POND
Hyd. No. 3 — 10 Year
360 480 600
Hyd No. 2
720
Wednesday, 07 / 12 / 2017
= 0.125 cfs
= 10 min
= 2,463 cuft
= 314.71 ft
= 2,445 cuft
Q (cfs)
10.00
. of
4.00
2.00
0.00
840 960 1080 1200 1320 1440 1560
Time (min)
® Total storage used = 2,445 cult

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.514 Wednesday, 07 / 12 / 2017
Hyd. No. 4
DA 1 - POST -DEVELOPMENT - BY-PASS POND
Hydrograph type
= Rational
Peak discharge
= 9.805 cfs
Storm frequency
= 10 yrs
Time to peak
= 5 min
Time interval
= 1 min
Hyd. volume
= 2,942 cuft
Drainage area
= 3.160 ac
Runoff coeff.
= 0.43
Intensity
= 7.216 in/hr
Tc by User
= 5.00 min
IDF Curve
= mid_NC_1yr.IDF
Asc/Rec limb fact
= 1/1
Q (cfs)
10.00
8.00
6.00
4.00
2.00
J
DA 1 - POST -DEVELOPMENT - BY-PASS POND
Hyd. No. 4 —10 Year
Q (cfs)
10.00
8.00
4.00
2.00
0.00 le I I I I I I I I I N 0.00
0 1 2 3 4 5 6 7 8 9 10
Hyd No. 4 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.514
Wednesday, 07 / 12 / 2017
Hyd. No. 5
DA 1 - POST -DEVELOPMENT WITH CONTROL
Hydrograph type
= Combine
Peak discharge
= 9.868 cfs
Storm frequency
= 10 yrs
Time to peak
= 5 min
Time interval
= 1 min
Hyd. volume
= 5,404 cuft
Inflow hyds.
= 3, 4
Contrib. drain. area
= 3.160 ac
DA 1 - POST -DEVELOPMENT WITH CONTROL
Q (cfs) fs
Q (c
Hyd. No. 5 —10 Year )
10.00 10.00
8.00 8.00
6.00 6.00
4.00 4.00
2.00 2.00
0.00 0.00
0 10 20 30 40 50 60 70 80 90
Hyd No. 5 Hyd No. 3 Hyd No. 4 Time (min)

Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.514
Wednesday, 07 / 12 / 2017
Hyd. No. 6
DA 1 - POST DEVELOPMENT - NO CONTROL
Hydrograph type
= Combine
Peak discharge
= 18.08 cfs
Storm frequency
= 10 yrs
Time to peak
= 5 min
Time interval
= 1 min
Hyd. volume
= 5,424 cult
Inflow hyds.
= 2, 4
Contrib. drain. area
= 4.980 ac
Deo 1 - POST DEVELOPMENT - NO CONTROL
Q (cfs) Hyd. No. 6 -- 10 Year
21.00
18.00
15.00 OF
12.00
9.00
6.00
3.00
0.00' I I I'
0 1 2 3 4
Hyd No. 6 Hyd No. 2
5 6 7
Hyd No. 4
I
Q (cfs)
21.00
18.00
15.00
12.00
3.00
3.00
3.00
M, 0.00
9 10
Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3DO 2016 by Autodesk, Inc. v10.514
Hyd. No. 7
DA 2 - PRE -DEVELOPMENT
Hydrograph type
= Rational
Peak discharge
Storm frequency
= 10 yrs
Time to peak
Time interval
= 1 min
Hyd. volume
Drainage area
= 0.340 ac
Runoff coeff.
Intensity
= 7.216 in/hr
Tc by User
IDF Curve
= mid_NC_1yr.IDF
Asc/Rec limb fact
Q (cfs)
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20 00,
0.10
000 -
DA
00
DA 2 - PRE -DEVELOPMENT
Hyd. No. 7 —10 Year
Wednesday, 07 / 12 / 2017
= 0.859 cfs
= 5 min
= 258 cuft
= 0.35
= 5.00 min
= 1/1
Q (cfs)
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0 00
0 1 2 3 4 5 6 7 8 9 10
Hyd No. 7 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D@2016 by Autodesk, Inc. v10.514
Hyd. No. 8
DA 2 - POST -DEVELOPMENT
Hydrograph type
= Rational
Peak discharge
Storm frequency
= 10 yrs
Time to peak
Time interval
= 1 min
Hyd. volume
Drainage area
= 0.290 ac
Runoff coeff.
Intensity
= 7.216 in/hr
Tc by User
IDF Curve
= mid_NC_1yr.IDF
Asc/Rec limb fact
Q (cfs)
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
000
DA 2 - POST -DEVELOPMENT
Hyd. No. 8 —10 Year
Wednesday, 07 / 12 / 2017
= 0.732 cfs
= 5 min
= 220 cuft
= 0.35
= 5.00 min
= 1/1
Q (cfs)
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0 00
0 1 2 3 4 5 6 7 8 9 10
Hyd No. 8 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.514 Wednesday, 07 / 12 / 2017
Hyd. No. 9
DA 3 -PRE- & POST -DEVELOPMENT - TO POND
Hydrograph type
= Rational
Peak discharge
= 8.529 cfs
Storm frequency
= 10 yrs
Time to peak
= 5 min
Time interval
= 1 min
Hyd. volume
= 2,559 cult
Drainage area
= 1.970 ac
Runoff coeff.
= 0.6
Intensity
= 7.216 in/hr
Tc by User
= 5.00 min
IDF Curve
= mid_NC_1yr.IDF
Asc/Rec limb fact
= 1/1
Q (cfs)
10.00
8.00
. fl
4.00
2.00
0.00 If I'
0 1 2
Hyd No. 9
DA 3 -PRE- & POST -DEVELOPMENT - TO POND
Hyd. No. 9 —10 Year
3 4 5 6 7 8 9
Q (cfs)
10.00
8.00
. 16
4.00
2.00
3- 0.00
10
Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.514
Wednesday, 07 / 12 / 2017
Hyd. No. 10
Ex. Dry Pond
Hydrograph type
= Reservoir
Peak discharge =
0.994 cfs
Storm frequency
= 10 yrs
Time to peak =
9 min
Time interval
= 1 min
Hyd. volume =
2,538 cuft
Inflow hyd. No.
= 9 - DA 3 -PRE- & POST-DEV®149it?NHW1tioTi0 POND=
310.43 ft
Reservoir name
= Ex. Dry Pond
Max. Storage =
2,159 cuft
Storage Indication method used.
Q (cf
10.00
8.00
6.00
4.00
2.00
n nn
Ex. Dry Pond
s) Hyd. No. 10 —10 Year
0 10 20
Hyd No. 10
30 40 50 60 70 80 90 100
— Hyd No. 9 ® Total storage used = 2,159 cuft
Q (cfs)
10.00
8.00
6.00
4.00
2.00
110
Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3130 2016 by Autodesk, Inc. v10.514
Wednesday, 07 / 12 / 2017
Hyd. No. 11
DA 3 - PRE- & POST -DEVELOPMENT - BY-PASS POND
Hydrograph type
= Rational
Peak discharge
= 15.07 cfs
Storm frequency
= 10 yrs
Time to peak
= 5 min
Time interval
= 1 min
Hyd. volume
= 4,520 cuft
Drainage area
= 5.220 ac
Runoff coeff.
= 0.4
Intensity
= 7.216 in/hr
Tc by User
= 5.00 min
IDF Curve
= mid_NC_1yr.IDF
Asc/Rec limb fact
= 1/,1
Q (cfs)
18.00
15.00
12.00
9.00
. IM
3.00
DA 3 - PRE- & POST -DEVELOPMENT - BY-PASS POND
Hyd. No. 11 —10 Year
0.00 - '
0 1 2
Hyd No. 11
3 4 5 6 7 8
Q (cfs)
18.00
15.00
12.00
9.00
M
Q1I11
% 0.00
9 10
Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.514
Wednesday, 07 / 12 / 2017
Hyd. No. 12
DA 3 - TOTAL PRE -DEVELOPMENT
Hydrograph type = Combine
Peak discharge
= 15.93 cfs
Storm frequency = 10 yrs
Time to peak
= 5 min
Time interval = 1 min
Hyd. volume
= 7,058 cuft
Inflow hyds. = 10, 11
Contrib. drain. area
= 5.220 ac
Q (cfs)
18.00
15.00
12.00
9.00
3.00
0.00 9'
0 10
Hyd No. 12
DA 3 - TOTAL PRE -DEVELOPMENT
Hyd. No. 12 —10 Year
20
Hyd No. 10
30 40
Hyd No. 11
50
Q (cfs)
18.00
15.00
12.00
9.00
6.00
3.00
Mld- 0.00
60
Time (min)

25 YEAR STORM

Hydrograph Summary Rep® qydraflow Hydrographs Extension for AutoCAD@) Civil 3DB 2016 by Autodesk, Inc. v10.514
Hyd.
No.
Hydrograph
type
(origin)
Peak
flow
(cfs)
Time
interval
(min)
Time to
Peak
(min)
Hyd.
volume
(cult)
Inflow
hyd(s)
Maximum
elevation
(ft)
Total
strge used
(cult)
Hydrograph
Description
1
Rational
1818
1
5
5,453
---
---
------
DA 1 - PRE -DEVELOPMENT
2
Rational
9.394
1
5
2,818
-- —
----
---
DA 1 - POST -DEVELOPMENT - TO
3
Reservoir
0.142
1
10
2,799
2
314.81
2,776
BIORETENTION POND
4
Rational
11 13
1
5
3,340
---
-- —
---
DA 1 - POST -DEVELOPMENT - BY -
5
Combine
11.20
1
5
6,138
3,4
----
---
DA 1 - POST -DEVELOPMENT WITH
6
Combine
2053
1
5
6,158
2, 4,
----
----
DA 1 - POST DEVELOPMENT - NO
7
Rational
0 975
1
5
292
--
--- -
---
DA 2 - PRE -DEVELOPMENT
8
Rational
0.832
1
5
249
--
----
--
DA 2 - POST -DEVELOPMENT
9
Rational
9 684
1
5
2,905
- --
--
— --
DA 3 -PRE- & POST-DEVELOPMEN
10
Reservoir
1.033
1
9
2,885
9
31052
2,481
Ex. Dry Pond
11
Rational
1711
1
5
5,132
---
------
-- -
DA 3 - PRE- & POST-DEVELOPMEN
12
Combine
17.99
1
5
8,017
10,11
------
--
DA 3 - TOTAL PRE -DEVELOPMENT
BioRetentlon.gpw
Return Period. 25 Year
Wednesday, 07 / 12 / 2017

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3130 2016 by Autodesk, Inc. v10.514 Wednesday, 07 / 12 / 2017
Hyd. No. 1
DA 1 - PRE -DEVELOPMENT
Hydrograph type
= Rational
Peak discharge
= 18.18 cfs
Storm frequency
= 25 yrs
Time to peak
= 5 min
Time interval
= 1 min
Hyd. volume
= 5,453 cuft
Drainage area
= 4.930 ac
Runoff coeff.
= 0.45
Intensity
= 8.193 in/hr
Tc by User
= 5.00 min
IDF Curve
= mid_NC_1yr.IDF
Asc/Rec limb fact
= 1/1
DA 1 - PRE -DEVELOPMENT
Q (cfs) Hyd. No. 1 — 25 Year
21.00
18.00
15.00
12.00 OF
9.00
6.00
3.00
000
0 1 2
Hyd No. 1
Q (cfs)
21.00
18.00
15.00
12.00
9.00
6.00
3.00
0.00
3 4 5 6 7 8 9 10
Time (min)

Hydrograph Report
Hydratlow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.514 Wednesday, 07 112 / 2017
Hyd. No. 2
DA 1 - POST -DEVELOPMENT - TOPOND
Hydrograph type
= Rational
Peak discharge
= 9.394 cfs
Storm frequency
= 25 yrs
Time to peak
= 5 min
Time interval
= 1 min
Hyd. volume
= 2,818 cuft
Drainage area
= 1.820 ac
Runoff coeff.
= 0.63 '
Intensity
= 8.193 in/hr
Tc by User
= 5.00 min
IDF Curve
= mid NC 1yr.IDF
Asc/Rec limb fact
= 1/1
DA 1 -POST-DEVELOPMENT - TO POND
Q (cfs) Hyd. No. 2 — 25 Year
10.00
8.00
H. fl
4.00
2.00
Q (cfs)
10.00
8.00
4.00
2.00
0.00
0 1 2 3 4 5 6 7 8 9 10
Hyd No. 2
Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.514 Wednesday, 07 / 12 / 2017
Hyd. No. 3
BIORETENTION POND
Hydrograph type
= Reservoir
Peak discharge
= 0.142 cfs
Storm frequency
= 25 yrs
Time to peak
= 10 min
Time interval
= 1 min
Hyd. volume
= 2,799 cuft
Inflow hyd. No.
= 2 - DA 1 - POST-DEVELOPMHPJR- 1110AGUiD
= 314.81 ft
Reservoir name
= Bioretention Pond 1
Max. Storage
= 2,776 cuft
Storage Indication method used. Outflow includes exfiltration.
Q (cfs)
10.00
8.00
M
4.00
2.00
BIORETENTION POND
Hyd. No. 3 — 25 Year
Q (cfs)
10.00
M
4.00
2.00
0.00 i 1 1 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 3 Hyd No. 2 ® Total storage used = 2,776 cult Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3130 2016 by Autodesk, Inc. v10.514 Wednesday, 07 / 12 / 2017
Hyd. No. 4
DA 1 - POST -DEVELOPMENT - BY-PASS POND
Hydrograph type
= Rational
Peak discharge
= 11.13 cfs
Storm frequency
= 25 yrs
Time to peak
= 5 min
Time interval
= 1 min
Hyd. volume
= 3,340 cult
Drainage area
= 3.160 ac
Runoff coeff.
= 0.43
Intensity
= 8.193 in/hr
Tc by User
= 5.00 min
IDF Curve
= mid_NC_1yr.IDF
Asc/Rec limb fact
= 1/1
Q (cfs)
12.00
10.00
8.00
4.00
2.00
DA 1 - POST -DEVELOPMENT - BY-PASS POND
Hyd. No. 4 — 25 Year
0.00 y I I I I I I I i
0 1 2 3 4 5 6 7 8
Hyd No. 4
Q (cfs)
12.00
10.00
8.00
6.00
4.00
2.00
N 0.00
9 10
Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil, 3D® 2016 by Autodesk, Inc. v10.514
Wednesday, 07 / 12 / 2017
Hyd. No. 5
DA 1 - POST -DEVELOPMENT WITH CONTROL
Hydrograph type
= Combine
Peak discharge
= 11.20 cfs
Storm frequency
= 25 yrs
Time to peak
= 5 min
Time interval
= 1 min
Hyd. volume
= 6,138 cuft
Inflow hyds.
= 3, 4
Contrib. drain. area
= 3.160 ac
10.00
8.00
4.00
2.00
DA 1 - POST -DEVELOPMENT WITH CONTROL
Hyd. No. 5 — 25 Year
0 10 20 30 40 50 60
Hyd No. 5 Hyd No. 3 Hyd No. 4
70 80
Q (cfs)
12.00
10.00
8.00
[ID117
4.00
2.00
90
Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 31X® 2016 by Autodesk, Inc. v10.514
Wednesday, 07 / 12 / 2017
Hyd. No. 6
DA 1 - POST DEVELOPMENT - NO CONTROL
Hydrograph type
= Combine
Peak discharge
= 20.53 cfs
Storm frequency
= 25 yrs
Time to peak
= 5 min
Time interval
= 1 min
Hyd. volume
= 6,158 cuft
Inflow hyds.
= 2, 4
Contrib. drain. area
= 4.980 ac
DA 1 - POST DEVELOPMENT - NO CONTROL
Q (cfs) Hyd. No. 6 — 25 Year
21.00
18.00
15.00
12.00
9.00
6.00 0or 00, Z-'O���
/00�
3.00
0 00
0 1 2 3 4
Hyd No. 6 Hyd No. 2
Q (cfs)
21.00
18.00
15.00
12.00
9.00
6.00
3.00
0.00
5 6 7 8 9 - 10
Hyd No. 4
Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3130 2016 by Autodesk, Inc. v10.514 Wednesday, 07 / 12 / 2017
Hyd. No. 7
DA 2 - PRE -DEVELOPMENT
Hydrograph type
= Rational
Peak discharge
= 0.975 cfs
Storm frequency
= 25 yrs
Time to peak
= 5 min
Time interval
= 1 min
Hyd. volume
= 292 cuft
Drainage area
= 0.340 ac
Runoff coeff.
= 0.35
Intensity
= 8.193 in/hr
Tc by User
= 5.00 min
IDF Curve
= mid_NC_1yr.IDF
Asc/Rec limb fact
= 1/1
Q (cfs)
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10 0z
000 -/ I
DA 2 - PRE -DEVELOPMENT
Hyd. No. 7 — 25 Year
Q (cfs)
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0 00
0 1 2 3 4 5 6 7 8 9 10
Hyd No. 7 Time (min)

Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.514
Hyd. No. s
DA 2 - POST -DEVELOPMENT
Hydrograph type
= Rational
Peak discharge
Storm frequency
= 25 yrs
Time to peak
Time interval
= 1 min
Hyd. volume
Drainage area
= 0.290 ac
Runoff coeff.
Intensity
= 8.193 in/hr
Tc by User
IDF Curve
= mid_NC_1yr.IDF
Asc/Rec limb fact
DA 2 - POST -DEVELOPMENT
Q (cfs) Hyd. No. 8 — 25 Year
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30 10,
0.20
0.10
000
0 1 2 3 4 5 6
Hyd No. 8
Wednesday, 07 112 / 2017
= 0.832 cfs
= 5 min
= 249 cuft
= 0.35
= 5.00 min
= 1/1
Q (cfs)
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
7 8 9 10
Time (min)

Hydr®graph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3138 2016 by Autodesk, Inc v10 514 Wednesday, 07 112 / 2017
Hyd. No. 9
DA 3 -PRE- & POST -DEVELOPMENT - TO POND
Hydrograph type
= Rational
Peak discharge
= 9.684 cfs
Storm frequency
= 25 yrs
Time to peak
= 5 min
Time interval
= 1 min
Hyd. volume
= 2,905 cuft
Drainage area
= 1.970 ac
Runoff coeff.
= 0.6
Intensity
= 8.193 in/hr
Tc by User
= 5.00 min
IDF Curve
= mid_NC_1yr.IDF
Asc/Rec limb fact
= 1/1
Q (cfs)
10.00
ME
.I�
4.00
2.00
0.00 " '
0 1
Hyd No. 9
DA 3 -PRE- & POST -DEVELOPMENT - TO POND
Hyd. No. 9 — 25 Year
2 3 4 5 6 7 8 9
Q (cfs)
10.00
8.00
. KI
4.00
2.00
--'_ 0.00
10
Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc v10.514
Wednesday, 07 / 12 / 2017
Hyd. No. 10
Ex. Dry Pond
Hydrograph type
= Reservoir
Peak discharge =
1.033 cfs
Storm frequency
= 25 yrs
Time to peak =
9 min
Time interval
= 1 min
Hyd. volume =
2,885 tuft
Inflow hyd. No.
= 9 - DA 3 -PRE- & POST-DEVBIW.NfflN1tioTiO POND=
310.52 ft
Reservoir name
= Ex. Dry Pond
Max. Storage =
2,481 cuft
Storage Indication method used.
0W
u.. .-5
Ex. Dry Pond
Hyd. No. 10 -- 25 Year
IR
W11
4.00
2.00
117
0 10 20
Hyd No. 10
Q (cfs)
10.00
Ij 61
M
4.00
2.00
- _NEAVA a
30 40 50 60 70 80 90 100
— Hyd No. 9 ® Total storage used = 2,481 cuft
110
Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3138 2016 by Autodesk, Inc. A 0.614
Wednesday, 07 / 12 / 2017
Hyd. No. 11
DA 3 - PRE- & POST -DEVELOPMENT - BY-PASS POND
Hydrograph type
= Rational
Peak discharge
= 17.11 cfs
Storm frequency
= 25 yrs
Time to peak
= 5 min
Time interval
= 1 min
Hyd. volume
= 5,132 cuft
Drainage area
= 5.220 ac
Runoff coeff.
= 0.4
Intensity
= 8.193 in/hr
Tc by User
= 5.00 min
IDF Curve
= mid_NC_1yr.IDF
Asc/Rec limb fact
= 1/1
Q (cfs)
18.00
15.00
12.00
9.00
mll
3.00
DA 3 - PRE- & POST -DEVELOPMENT - BY-PASS POND
Hyd. No. 11 — 25 Year
0.00 ; 1 '
0 1 2
Hyd No. 11
Q (ds)
18.00
15.00
12.00
9.00
6.00
3.00
' 1 0.00
3 4 5 6 7 8 9 10
Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D@2016 by Autodesk, Inc, v10.514
Wednesday, 07 / 12 / 2017
Hyd. No. 12
DA 3 - TOTAL PRE -DEVELOPMENT
Hydrograph type = Combine
Peak discharge
= 17.99 cfs
Storm frequency = 25 yrs
Time to peak
= 5 min
Time interval = 1 min
Hyd. volume
= 8,017 cuft
Inflow hyds. = 10, 11
Contrib. drain. area
= 5.220 ac
Q (cfs)
18.00
15.00
12.00
aM
3.00
0.00 ' — `-
0 10
Hyd No. 12
DA 3 - TOTAL PRE -DEVELOPMENT
Hyd. No. 12 — 25 Year
20
Hyd No. 10
30 40
Hyd No. 11
50
Q (cfs)
18.00
15.00
12.00
• II
. IX
3.00
==- 0.00
60
Time (min)

100 YEAR STORM SUMMARY

Hydrograph Summary Rep® qydraflow Hydrographs Extension for AutoCAD® Civil 3130 2016 by Autodesk, Inc. v10 514
Hyd.
No.
Hydrograph
type
(origin)
Peak
flow
(cfs)
Time
interval
(min)
Time to Hyd.
Peak volume
(min) (cuft)
Inflow
hyd(s)
Maximum Total Hydrograph
elevation strge used Description
(ft) (cuft)
1
Rational
21 56
1
5 6,469
---
--- --- DA 1 - PRE -DEVELOPMENT
2
Rational
11.14
1
5 3,343
---
--- -- DA 1 - POST -DEVELOPMENT - TO
3
Reservoir
0.168
1
10 3,324
2
314.96 3,293 BIORETENTION POND
4
Rational
13.21
1
5 3,962
--
--- ---- DA 1 - POST -DEVELOPMENT - BY -
5
Combine
13.29
1
5 7,286
3,4
---- --- DA 1 - POST -DEVELOPMENT WITH
6
Combine
24.35
1
5 7,306
2, 4,
--- -- DA 1 - POST DEVELOPMENT - NO
7
Rational
1 157
1
5 347
---
----- --- DA 2 - PRE -DEVELOPMENT
8
Rational
0.987
1
5 296
--
--- --- DA 2 - POST -DEVELOPMENT
9
Rational
1149
1
5 3,447
---
--- ----- DA 3 -PRE- & POST-DEVELOPMEN
10
Reservoir
1 091
1
10 3,426
9
31066 2,990 Ex. Dry Pond
11
Rational
2030
1
5 6,089
---
---- ---- DA 3 - PRE- & POST-DEVELOPMEN
12
Combine
21 22
1
5 9,515
10,11
--- ---- DA 3 - TOTAL PRE -DEVELOPMENT
BioRetention.gpw Return Period: 100 Year Wednesday, 07 / 12 / 2017

TIME OF CONCENTRATION
CALCULATIONS

TR55 Tc Worksheet
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D@2016 by Autodesk, Inc v10 514
Hyd. No. 1
DA 1 - PRE -DEVELOPMENT
Description
A
B
C
Totals
Sheet Flow
Manning's n -value
= 0.011
0.011
0.011
Flow length (ft)
= 0.0
0.0
0.0
Two-year 24 -hr precip. (in)
= 0.00
0.00
0.00
Land slope (%)
= 0.00
0.00
0.00
Travel Time (min)
= 0.00 +
0.00 +
0.00 =
0.00
Shallow Concentrated Flow
Flow length (ft)
= 35.00
203.00
0.00
Watercourse slope (%)
= 0.50
2.50
0.00
Surface description
= Unpaved
Unpaved
Paved
Average velocity (ft/s)
=1.14
2.55
0.00
Travel Time (min)
= 0.51 +
1.33 +
0.00 =
1.84
Channel Flow
X sectional flow area (sqft)
= 3.00
0.00
0.00
Wetted perimeter (ft)
= 8.00
0.00
0.00
Channel slope (%)
= 1.50
0.00
0.00
Manning's n -value
= 0.015
0.015
0.015
Velocity (ft/s)'
=6.31
0.00
0.00
Flow length (ft)
({0))780.0
0.0
0.0
Travel Time (min)
= 2.06 +
0.00 +
0.00 =
2.06
Total Travel Time, Tc..............................................................................
3.90 min

TR55 Tc Worksheet
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D@2016 by Autodesk, Inc v10.514
Hyd. No. 2
DA 1 - POST -DEVELOPMENT - TO POND
Description
A
B
C
Totals
Sheet Flow
Manning's n -value
= 0.011
0.011
0.011
Flow length (ft)
= 0.0
0.0
0.0
Two-year 24 -hr precip. (in)
= 0.00
0.00
0.00
Land slope (%)
= 0.00
0.00
0.00
Travel Time (min)
= 0.00 +
0.00 +
0.00 =
0.00
Shallow Concentrated Flow
Flow length (ft)
= 35.00
0.00
0.00
Watercourse slope (%)
= 0.50
0.00
0.00
Surface description
= Unpaved
Paved
Paved
Average velocity (fUs)
=1.14
0.00
0.00
Travel Time (min)
= 0.51 +
0.00 +
0.00 =
0.51
Channel Flow
X sectional flow area (sqft)
= 3.00
0.00
0.00
Wetted perimeter (ft)
= 8.00
0.00
0.00
Channel slope (%)
= 1.00
0.00
0.00
Manning's n -value
= 0.015
0.015
0.015
Velocity (ft/s)
=5.15
0.00
0.00
Flow length (ft)
Q0})790.0
0.0
0.0
Travel Time (min)
= 2.56 +
0.00 +
0.00 =
2.56
Total Travel Time, Tc..............................................................................
3.07 min

TR55 Tc Worksheet
Hydraflow Hydrographs Extension for AutoCAD® Civil 3DO 2016 by Autodesk, Inc v10 514
Hyd. No. 2
DA 1 - POST -DEVELOPMENT - TO POND
Description
A
B
C
Totals
Sheet Flow
Manning's n -value
= 0.150
0.011
0.011
Flow length (ft)
= 30.0
0.0
0.0
Two-year 24 -hr precip. (in)
= 2.20
0.00
0.00
Land slope (%)
= 4.00
0.00
0.00
Travel Time (min)
= 3.42 +
0.00 +
0.00 =
3.42
Shallow Concentrated Flow
Flow length (ft)
= 150.00
0.00
0:00
Watercourse slope (%)
= 2.00
0.00
0.00
Surface description
= Unpaved
Paved
Paved
Average velocity (ft/s)
=2.28
0.00
0.00
Travel Time (min)
= 1.10 +
0.00 +
0.00 =
1.10
Channel Flow
X sectional flow area (sqft)
= 530.00
0.00
0.00
Wetted perimeter (ft)
= 6.00
0.00
0.00
Channel slope (%)
= 1.50
0.00
0.00
Manning's n -value
= 0.025
0.015
0.015
Velocity (ft/s)
=146.96
0.00
0.00
Flow length (ft)
({0})530.0
0.0
0.0
Travel Time (min)
= 0.06 . +
0.00 +
0.00 =
0.06
TotalTravel Time, Tc..............................................................................
4.57 min