SW4210401_STORMWATER_CALCS_SAND_FILTER_UNDERGROUND_20210426

BROWN APARTMENTS
BOONE, NC
HYDROLOGIC AND HYDRAULIC ANALYSIS REPORT
BREC
•�ti
Prepared By:
Prepared For:
Project Site:
BREC, P.A.
Kent Brown
599 Old US 421 South
1520 Meadowview Drive
Boone, NC 28607
Wilkesboro, NC 28697
NCBELS Firm #C-3448
[phone]
[e-mail]
15 April 2021
CARo /''%
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Justin Church, PE
Principal Engineer
BREC, P.A.
Brown Apartments 1

Table of Contents
1.0 General Information........................................................................................3
2.0 Methodology...................................................................................................3
2.1 Curve Number Calculations
3
2.2 Time of Concentration Calculations
4
2.3 Rainfall Data
5
2.4 Pipe Design
5
2.4.1 Outlet Design
6
2.5 Hydrology Calculations
7
2.6 Modified Curve Number Calculations
7
2.7 Sand Filter Design
8
2.7.1 Chamber and Filter Sizing
8
2.7.2 Underdrain Sizing
8
3.0 Results ..........................................................................................................10
Appendix.............................................................................................................11
Post -construction First Flush
Post -construction 1 Year, 24 Hour
Post -construction 100 Year, 24 Hour
List of Figures
Figure 1 - System Storage of First Flush............................................................10
List of Tables
Table 1 - Pre -Construction Drainage Area............................................................3
Table 2 - Post -Construction Drainage Areas........................................................4
Table 3 - Pre -Construction ToC............................................................................4
Table 4 - Post -Construction ToC...........................................................................4
Table 5 - NOAA Rainfall Depths...........................................................................5
Table 6 - NOAA Rainfall Intensity.........................................................................5
Table 7 - Composite Rational Coefficients............................................................5
Table 8 - Pipe Design Summary ...........................................................................5
Table 9 - Riprap Outlet Stone Sizing.....................................................................6
Table 10 - Riprap Apron Dimensions....................................................................6
Table 11 - Modified SCS Curve Numbers.............................................................7
Table 12 - Post Construction SCM Peak Elevations...........................................10
BREC, P.A. Brown Apartments
2

1.0 General Information
This document contains hydrologic and hydraulic calculations demonstrating
compliance with post -construction state and local stormwater regulations for the
construction of a three story residential apartment building with a 6,044 ft2
footprint at 599 Old US 421 South, Boone, NC. Specifically, regulations for this
area require water quality treatment of the first flush (1") storm due to the site being
located within the portion of the South Fork New River watershed classified as C+.
The construction area is a portion of an existing development that includes a
gym/fitness center and parking. The building footprint is the only added
impervious. Post construction stormwater requirements will be satisfied with a
below ground sand filter which is approved by NCDEQ as a primary stormwater
control measure (SCM).
2.0 Methodology
One pre -construction drainage area and one post -construction drainage area
covering the building pad area was identified. All net proposed impervious area is
routed to the SCM for treatment prior to discharge.
2.1 Curve Number Calculations
Composite SCS curve numbers were calculated as weighted averages using
values of 74 for grass coverage, 70 for wooded areas, and 98 for impervious
surfaces. Design values were based on HSG C soils as they are the majority.
For pre -construction drainage areas, the composite curve number is calculated as:
(Aimp x 98 + Agrass x 74 + Awooded x 70)
CNComhpre
Atotal
Table 1 - Pre -Construction Drainaae Area
Name
Atotal
(acres)
Aimp
acres
Agrass
acres
Awooded
(acres)
CNcom ppre
PRE-CONA
0.17
0
74.0
0
74.0
For post -construction drainage areas, the composite curve number is calculated
as:
CNcompositepost
(Aimp x 98 + Agrass x 74 + Awooded x 70)
Atotal
BREC, P.A. Brown Apartments 3

Table 2 - Post -Construction Drainage Areas
+ Routed through SCM prior to discharge.
2.2 Time of Concentration Calculations
Time of concentration values for vegetated drainage areas were evaluated using
the segmental equations. All majority impervious drainage areas
less than one
acre were assigned a design time of concentration value of five minutes.
Tcsegmental (hr) = Tsheet + Tscf
0.007(nl)0.8
Tsheet =
2S0.4
2
n = Manning's coefficient
PZ = 2 yr, 24 hr rain f all (in)
ft
S = slope (
)
t
f
l
Tscf
3,600V
ft
1
V = shallow concentrated flow velocity (S)
Table 3 - Pre -Construction ToC
Table 4 - Post -Construction ToC
See Table 15-3 of USDA NRCS NEH for shallow concentrated flow velocity equations.
BREC, P.A. Brown Apartments
4
Name
Atotal
(acres)
Aimp
acres
Agrass
acres
Awooded
(acres)
CNcom pnost
POST-CON:1+
0.17
0.17
0
0
98.0
Name
Slope
Tc—talc
Tc—assumed
;Length
t
t
min
min
PRE-CON:1
-
-
-
Name
Length
S10�7e
Tc—talc
Tc—assumed
t
t
min
min
POST-CON:1
-
-
-
5

2.3 Rainfall Data
Rainfall data was taken from NOAA Atlas 14, Volume 2, Version 3 for Stokesdale,
NC. Rainfall depths for each design storm are summarized below.
Table 5 - NOAA Rainfall Deaths
Storm
Rainf all Depth in
First Flush
1.00
1 Year, 24 Hour
3.72
100 Year, 24 Hour
10.90
Table 6 - NOAA Rainfall Intensitv
10 Year Storm Duration min
Rainfall Intensity in/hr
5
7.48
2.4 Pipe Design
A composite post -construction rational coefficient was also assigned to each post
construction drainage area as needed for pipe design. The composite rational
coefficients were calculated using individual coefficients of 0.95 for impervious
surfaces, 0.20 - 0.30 for grass surfaces, and 0.15 for wooded areas in HSG C soils.
Ccomp —
Almp x 0.95 + Agrass x (0.20, 0.30) + Awooded x 0.15
Atotal
Table 7 - Composite Rational Coefficients
ft3
Name
CComp
Q10
s
POST-CONA
0.95
1.19
The 10 year rational discharges were used to size pipes by solving Manning's
equation iteratively for the normal depth.
Table 8 - Pine Design Summary
NAME
DIA (in)
Qdesign (f't3S)
1 t
Vdesign()
s
PIPE-1
15
1.2
3.9
See Appendix for complete pipe design table.
BREC, P.A. Brown Apartments 5

2.4.1 Outlet Design
Outlet design for NCDOT-PIPE-1, PIPE-4, PIPE-5, and PIPE-9 was taken from
Chapter 10 of HEC-14. Riprap D50 was calculated as:
4
D50 = 0.21) Qdesign3 ( D )
(jgD2.5) TWWhere,
D50 = riprap size, (f t)
ft3
Qdesign = Design discharge —
s
D = Pipe diameter, (f t)
TW = Tailwater depth, (f t)
g = gravitational acceleration (32.2 t
sZ)
Substituting the corresponding pipe diameters and design discharges into the
equation above for PIPE-1 yields:
Table 9 - Ri ra Outlet Stone Sizing
NAME DIA (ill) Qdesign (A minimum D50 of 5 inches was chosen for each pipe which corresponds to
NCDOT Class A stone. Given the design D50, the dimensions of the apron were
taken from Table 10.1 equations from HEC 142.
La = Apron length (f t) = 4D
Da = Apron depth (f t) = 3.5D50
W1 = Upper width (f t) = 3D
W2 = Lower width (f t) = 3D + (3)La
Table 10 - Ri ra Aron Dimensions
z http://www.fhwa.dot.gov/engineering/hydraulics/pubs/06086/hec14ch10.cfm
BREC, P.A. Brown Apartments 6
f s3 D50calc (ill) D50design (in)
NCDOT CLASS
PIPE-1
15
1.2
0.7
5
A
NAME
DIA (in)
La (ft)
Da (ft)
W1 (ft)
WZ (ft)
PIPE-1
15
5
1.5
3.8
7.1

2.5 Hydrology Calculations
The water quality volume (WQV) required to be treated from the first flush was
calculated using the Schueler method outlined in the NCDEQ Stormwater Design
Manual3. The Schueler method utilizes the following equations:
R„=0.05+0.9IA
WQV = 3,630RDR„ A
Where IA is the impervious fraction of the drainage area, R„ is a runoff coefficient,
RD is the rainfall depth, A is the drainage area, and WQ„ is the runoff volume. The
following parameters are used for the drainage routed to the SCM.
Ia = 1.0
R„ = 0.05 + 0.9(1.0) = 0.95
RD = 1.0 inch
A = 0.17
WQV = 3,630(1.0)(0.95)(0.17) = 576 f t3
WQVadj = 0.75WQ„ = 0.75(576) = 432 ft3
2.6 Modified Curve Number Calculations
To route the WQV through the SCM, it is necessary to calculate a modified SCS
curve number to avoid underrepresenting the first flush. The modified curve
number is calculated as follows:
CN,,, = 1000/ 110 + 5RD + 10R„ — 10 Rv + 1.25R„RD]
The modified curve numbers were used to route the first flush using an SCS 6 hour
balanced storm distribution. The remaining design storms were routed with
standard curve numbers and an SCS type II 24 hour storm distribution.
Table 11 -Modified SCS Curve Numbers
Name
R
CN
POST-CON:1
0.95
99.57

2.7 Sand Filter Design
The combined area of the sediment chamber and sand chamber is determined
from the relationship of the max water depth observed during the water quality
event, Hmax, and the adjusted water quality volume.
(As + Af )min W QVad j lHmax
The design value for Hmax was chosen as 2.0 ft. When coupled with the adjusted
water quality volume, WQVadj = 0.75WQV = 432 ft3, the minimum area of the
sand filter is calculates as:
_ 432 ft3
(As + Af)min — 2 ft = 216 ft2
As + Af provided = 232 ft2
2
2.7.1 Chamber and Filter Sizing
The sediment chamber and filter chamber are equally sized. The sediment
chamber has a 2 ft permanent pool to assist with maintenance and primary
sediment deposition; however, this added volume is not considered in calculations
to meet minimum design criteria requirements. The sediment and sand chamber
sizes were selected from available sizes of traffic rated pre -cast tanks available at
a local provider. This yields a sand media area, Ascend, of 80 ft2 (8 x 10 ft2).
Discharge through the sand media is governed by Darcy's Law.
Asandk(ha + df)
Qsand = df
Where,
Asand = Sand media surface area (f t2) = 80 ft2
_ da
k = Sand media permeability ft (day) 4.0 ft
Y
df = Sand media depth (ft) = 1.5 ft
ha = Average height of water above sand media
2.7.2 Underdrain Sizing
Drawdown time is calculated as:
BREC, P.A. Brown Apartments 8

WQVdf 576(1.5)
t = _ = 25.9 hours
k(ha + df)Asand 4.0(1.0 + 1.5)80
Discharge rate is calculated as:
WQV 576 f t3
Qunderdrain — t 25.9 0.006 s
After applying a safety factor of 10,
ft3
Qunderdraintotal 10Qunderdrain = 0.06 t
The diameter of a single pipe is calculated as-
3
D = 16 nQunderdraintotal 8
Where,
n = Manning's roughness f or pipe
S = pipe slope
3
(0.011(0.06)
$
D = 16 = 2.8 inches
0.005
Per Table 1 of Section A-5 of the NCDEQ Stormwater Design Manual, use (2) 4
inch pipes.
BREC, P.A. Brown Apartments 9

3.0 Results
The first flush (1") storm is routed through the SCM and reaches a max storage
depth of 1.99 ft which does not exceed the design Hmax = 2.0 ft. The water
quality volume is discharged over a period of 26.5 hours.
— Storagesystem (POST -CON -ROUTING 2021-04-1s 11'. 51'S4)
765
714
663
612
561
m 510
!n
459
408
357
306
0 5 10 15 20 25 30 35 40 45
Time (hrs)
Figure 1 - System Storage of First Flush
Table 12 - Post Construction SCM Peak Elevations
Storm
PEAK ELEVATION ( t)
1 Inch
3075.99
1 Year, 24 Hour
3076.10
100 Year, 24 Hour
3076.20

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Post -construction First Flush
BREC, P.A. Brown Apartments 12

Project Description
File Name...................................................................
POST -CON -ROUTING BALANCED.SPF
Project Options
FlowUnits...................................................................
CFS
Elevation Type............................................................
Elevation
Hydrology Method ......................................................
SCS TR-55
Time of Concentration (TOC) Method ........................
User -Defined
Link Routing Method ..................................................
Hydrodynamic
Enable Overflow Ponding at Nodes ...........................
YES
Skip Steady State Analysis Time Periods ..................
YES
Analysis Options
Start Analysis On ........................................................
Feb 09, 2021
000000
End Analysis On .........................................................
Feb 11, 2021
000000
Start Reporting On .....................................................
Feb 09, 2021
00:00:00
Antecedent Dry Days ..................................................
0
days
Runoff (Dry Weather) Time Step ...............................
0 01:0000
days hh:mm:ss
Runoff (Wet Weather) Time Step ..............................
0 00:05:00
days hh:mm:ss
Reporting Time Step ..................................................
0 00:00:05
days hh:mm:ss
Routing Time Step ......................................................
5
seconds
Number of Elements
Qty
RainGages................................................................
1
Subbas in s....................................................................
1
Nodes..........................................................................
4
Junctions
1
Outfalls
1
Flow Diversions
0
Inlets
0
Storage Nodes
2
Links............................................................................
4
Channels
0
Pipes
1
Pumps
0
Orifices
1
Weirs
1
Outlets
1
Pollutants....................................................................
0
LandUses..................................................................
0
Rainfall Details
SN Rain Gage Data Data Source
Rainfall
Rain State County Return Rainfall Rainfall
ID Source ID
Type
Units Period Depth Distribution
(years) (inches)
1 BOONE Time Series 1-IN-6HR-BALANCED Cumulative
inches 0.00

Subbasin Summary
SN Subbasin Area Peak Rate Weighted Total Total Total Peak Time of
ID Factor Curve Rainfall Runoff Runoff Runoff Concentration
Number Volume
(ac) (in) (in) (ac-in) (cfs) (days hh:mm:ss)
1 POST-CON:1 0.17 484.00 99.57 1.00 0.95 0.16 0.35 0 00:05:00

Node Summary
SIN Element
Element
Invert Ground/Rim
Initial Surcharge Ponded Peak Max HGL
Max
Min
Time of Total
ID
Type
Elevation
(Max)
Water Elevation
Area Inflow Elevation
Surcharge Freeboard
Peak Flooded
Elevation
Elevation
Attained
Depth
Attained
Flooding Volume
Attained
Occurrence
(ft)
(ft)
(ft) (ft)
(ft') (cfs) (ft)
(ft)
(ft)
(days hh:mm) (ac-in)
1 SCM-OUTLET
Junction
3071.75
3079.00
3071.75 0.00
0.00 0.01 3071.78
0.00
7.22
0 0000 0.00
2 OUTFALL
Outtall
3071.50
0.01 3071.53
3 SAND -CHAMBER
Storage Node
3074.00
3077.50
3074.00
0.00 0.51 3076.00
0.00
4 SEDIMENT -CHAMBER Storage Node
3072.00
3077.50
3074.25
0.00 0.35 3076.01
0.00

Total Time
Flooded
(min)
0.00
0.00
0.00

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ow a
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M M M
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N V V
r r r
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M M M
Ir
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2 Ir Ir
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=mm
U < <
F Q Q
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Subbasin Hydrology
Subbasin : POST-CONA
Input Data
Area(ac).....................................................
0.17
Peak Rate Factor ........................................
484.00
Weighted Curve Number ............................
99.57
Rain Gage ID ...............................................
BOONE
Composite Curve Number
Area
Soil Curve
Soil/Surface Description
(acres)
Group Number
-
0.17
- 99.57
Composite Area & Weighted CN
0.17
99.57
Subbasin Runoff Results
Total Rainfall (in) .........................................
1.00
Total Runoff (in) ..........................................
0.95
Peak Runoff (cfs)........................................
0.35
Weighted Curve Number ............................
99.57
Time of Concentration (days hh:mm:ss) .....
0 00:05:00

Subbasin : POST-CON:1
2.3
2.2
2.1
2
1.9
1.8
1.7
1.6
1.5
1.4
1.3
_- L2
� 1
0
0.9
0.8
0.7
06
0.5
0.4
0.3
0.2
0.1
0.30
0.36
0.34
032
0.3
0.28
0.26
0.24
0.22
0.2
0.18
0.16
0.14
0.12
0.1
008
0.06
004
0.02
Rainfall Intensity Graph
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48
Time [hrs]
Runoff Hydrograph
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46
Time [hrs]

Junction Input
SIN Element Invert Ground/Rim Ground/Rim Initial Initial Surcharge Surcharge Ponded Minimum
ID Elevation (Max) (Max) Water Water Elevation Depth Area Pipe
Elevation Offset Elevation Depth Cover
(ft) (ft) (ft) (ft) (ft) (ft) (ft) (ft) (in)
1 SCM-OUTLET 3071.75 3079.00 7.25 3071.75 0.00 0.00-3079.00 0.00 0.00

Junction Results
SIN Element Peak Peak Max HGL Max HGL
Max
Min Average HGL Average HGL
Time of
Time of Total Total Time
ID Inflow Lateral Elevation
Depth Surcharge Freeboard
Elevation
Depth
Max HGL
Peak Flooded Flooded
Inflow Attained
Attained
Depth
Attained
Attained
Attained
Occurrence
Flooding Volume
Attained
Occurrence
(cfs) (cfs) (ft)
(ft)
(ft)
(ft)
(ft)
(ft)
(days hh:mm)
(days hh:mm) (ac-in) (min)
1 SCM-OUTLET 0.01 0.00 3071.78
0.03
0.00
7.22
3071.76
0.01
0 04:59
0 00:00 0.00 0.00

Pipe Input
SIN Element Length Inlet Inlet Outlet Outlet Total Average Pipe Pipe Pipe Manning's Entrance Exit/Bend Additional Initial
ID Invert Invert Invert Invert Drop Slope Shape Diameteror Width Roughness Losses Losses Losses Flow
Elevation Offset Elevation Offset Height
(ft) (ft) (ft) (ft) (ft) (ft) (%) (in) (in) (cfs)
1 SCM-OUTLET-LINK 10.00 3071.75 0.00 3071.50 0.00 0.25 2.5000 CIRCULAR 15.000 15.000 0.0120 0.5000 0.5000 0.0000 0.00

Flap No. of
Gate Barrels
No 1

Pipe Results
SN Element Peak Time of Design Flow Peak Flow/ Peak Flow Travel Peak Flow Peak Flow Total Time Froude Reported
ID Flow Peak Flow Capacity Design Flow Velocity Time Depth Depth/ Surcharged Number Condition
Occurrence Ratio Total Depth
Ratio
(cfs) (days hh:mm) (cfs) (ft/sec) (min) (ft) (min)
1 SCM-OUTLET-LINK 0.01 0 05:00 11.06 0.00 1.32 0.13 0.03 0.02 0.00 Calculated

Storage Nodes
Storage Node : SAND -CHAMBER
Input Data
Invert Elevation (ft).......................................................................................
3074.00
Max (Rim) Elevation (ft)...............................................................................
3077.50
Max (Rim) Offset (ft)....................................................................................
3.50
Initial Water Elevation (ft).............................................................................
3074.00
Initial Water Depth (ft)..................................................................................
0.00
Ponded Area (ft')..........................................................................................
0.00
EvaporationLoss.........................................................................................
0.00
Storage Area Volume Curves
Storage Curve : SAND -CHAMBER
Stage Storage Storage
Area Volume
0 104 0.000
2.5 104 260.00
2.6 1 265.25
3.6 1 266.25

2
2
2
2
2
2
2
2
2
0
0
0
0
0
0
0
0
0
Storage Area Volume Curves
Storage Volume (ft)
0 40 20 30 40 50 60 70 80 90 100 110 420 430 140 450 460 170 180 490 200 240 220 230 240 260 260
6----,----------------------------------------------------------------------------- v---------------- - - ---
3.6
5---------------- --------- ------------------------ --- ------- -- - - 3.5
4 ---i------ --i---r---7------- i------- ------------------------------- 7 - - - 7-------------- ------ 3.4
3--- '----------- •---'---`---`------- '--- '---`---`-- - - - - 3.3
2 --- --- - -- - -- --- --- --- --- ------ --- --- --- --- - ------ - - - - -- - -- - -- - -- - -- --- --- -- - --- -- 3.2
7---'---'---'---•---'---`---`---`-- '--- '---`---`-- - - - - 3.1
3 --- - -- - -- - -- - -- --- --- --- - - -- -- --- --- --- --- ------- - - - - -- --- - -- - -- --- - -- - -- - - -- -- -- 3
9 ---'---'---'--- I-------`---`---`-- - - - - 2.9
8 - -- *- - - * - -- -- -- - ------------- --- --- --- --- --- --- ------ -- 2.8
6----- -- ------ --- --- --- --- --- --- ------ - 2.6
4 *---*--- -- -- - --- ------------- --- --- --- --- --- --- -- -- 2.4
3-- - - - - -- - ----------------------------------------------------- - - - - ------------ 2.3
2'---"--------'---------------'---'-- '---"---"---'---'--- - - - - 2.2
7-- - - - - -- - - -------------------------------------------- - - -- -------------- ------ 2.1
2 - - - ................................. - - - 2
9-------- - --------------------------------------------------------------------- 1.9
8 ------------------------------------ - - - - 7.8
6---------*--- --------------�--- --- ---- ---- --- --- --- --- --- --- ------ -- 7.6
5-- - - - - -- - - -- ------------------- - - -- --------------------------------------- - - - -- 7.5
4'---"---"---"---'---•---•---'---'-- -----I'---"---'--- - - - - 1.4
3;---;---'---'---;---'---;---;----I--- ------------------------------- 7.3
2---'---'---'---•--- `---`---`-- '---'---'--`---`-- - - - - 1.2
7 --- --- --- - -- - -- - -- --- --- - - -- -- - -- - - -- --- - ---------- -- --- - -- - -- - -- ---
--- ------ -- 7.7
9-
------------- ---- ------- - - -- -- ,---,---,------------ ,---,---.---.------ 0.9
7---- ;--- ;- - -T--- -- - -- ;--- ;- - - - - -- - --- -------- --- --- --- --- -- - --- -- 0.7
5 ---------- - -- - -- -- -- ;---;---;-- --- ------- - - -- -- I--- --- --- --- --- - -- - - - --- -- 0.5
3 ;---;-- T--- -- -- ----------- --- ------------- --- --- --- --- --- --- ------ -- 0.3
2--------------------------------------------------------------- 4.2
7 -- ------*--- --- -- --- ------�--- ------------- --- --- --- --- --- --- ------ -- 0.1
4 4
5 40 75 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
Storage Area (ft)
Storage Area — Storage Volume

Storage Node : SAND -CHAMBER (continued)
Outflow Weirs
SIN Element Weir Flap Crest Crest Length Weir Total Discharge
ID Type Gate Elevation Offset Height Coefficient
(ft) (ft) (ft) (ft)
1 EM-SPILLWAY Rectangular No 3076.25 2.25 8.00 0.25 3.33
Output Summary Results
Peak Inflow (cfs)..........................................................................................
0.51
Peak Lateral Inflow (cfs)..............................................................................
0.00
Peak Outflow (cfs)........................................................................................
0.31
Peak Exfiftration Flow Rate (cfm).................................................................
0.00
Max HGL Elevation Attained (ft)...................................................................
3076.00
Max HGL Depth Attained (ft)........................................................................
2
Average HGL Elevation Attained (ft)............................................................
3074.50
Average HGL Depth Attained (ft).................................................................
0.5
Time of Max HGL Occurrence (days hh:mm)..............................................
0 0459
Total Exfiltration Volume (1000-ft3)..............................................................
0.000
Total Flooded Volume (ac-in).......................................................................
0
Total Time Flooded (min).............................................................................
0
Total Retention Time (sec)...........................................................................
0.00

Storage Node : SEDIMENT -CHAMBER
Input Data
Invert Elevation (ft).......................................................................................
3072.00
Max (Rim) Elevation (ft)...............................................................................
3077.50
Max (Rim) Offset (ft)....................................................................................
5.50
Initial Water Elevation (ft).............................................................................
3074.25
Initial Water Depth (ft)..................................................................................
2.25
Ponded Area (ft2)..........................................................................................
0.00
EvaporationLoss.........................................................................................
0.00
Storage Area Volume Curves
Storage Curve : SEDIMENT -CHAMBER
Stage
Storage
Storage
Area
Volume
(ft)
(ft2)
(ft')
0
128
0.000
4.5
128
576.00
4.6
1
582.45
5.6
1
583.45

Storage Area Volume Curves
S101a9e Volume (ft)
0 50 100 150 200 250 300 360 400 460 600 660
G.6
5.6
G.4--------------------
'--------'--------•--------'--------'--------- '---------------------------------------------
6.4
1.2
---------- ---------- --------'-----------------`--------'---------'--------'--------'--------'--------------
5.2
6
------- ----- ------ ------ ------ ----- ----- ----- ----- ------ ------ ----
5
66
'--------'--------'-------- `-------- '--------- '------------------'--------'--------`-----
4.6
64
------------------------- --
4.4
4
-------- -------- -------- -------- -------- ------------------------- -------- -------- ------ -----
4
1.6
'-------- '--------'--------'--------'--------`-------- '--------- -------- '--------'----- --------- -----
3.6
1.6
; ; ;-- - - - - -� -----
3.6
1.4
'---------- --------'--------'-----------------`--------'---------'--------'------'-----------------------
3.4
1.2
-------------------------------------------------------------------- --------------------------------
3.2
3
---------------------------------------------------------------------------------------------------
3
!.8
-----------------------------------------------------------------------------------------------------
2.8
!.6
-----------------'--------'------------------------------------------------------------------ ------
2.6
!.4------------------------------------------------
-----------------------------------4---------------
2.4
!.2
-------------------'--------'------------------------------------------------------------------ ------
2.2
2
----- ----- ------ ------ ------ ----- ----- ----- ----- ------ ------ ----
2
I.6
'--------'--------'--------'--------'-------`--------'---------'--------'--------'--------'--------`-----
1.6
1
-------- -------- -- --- -------- -------- ------------------------- -------- -------- -------- -----
1
1.6
-------- '--------�------- '--------'--------`-------- '--------- '-------- '--------'--------'-------- -----
0.6
1.6
;- - -- - - -; ; � - - - --
0.6
1.4
----------------'--------'--------f--------------------------------------------'----------------------
4.4
1.2----
---------------------------------------------------------------------------------------------
0.2
0
0
0 5 10 15 20 25 30 35 40 45 50 65 60 65 70 76 80 85 90 95 100 105 110 115 120 125
Storage Area (ft)
Storage Area - Storage Volume

Storage Node : SEDIMENT -CHAMBER (continued)
Outflow Orifices
SN Element Orifice Orifice Flap Circular Rectangular Rectangular Orifice Orifice
ID Type Shape Gate Orifice Orifice Orifice Invert Coefficient
Diameter Height Width Elevation
(in) (in) (in) (ft)
1 CHAMBER -CONNECTION Side CIRCULAR No 15.00 3074.00 0.61
Output Summary Results
Peak Inflow (cfs)..........................................................................................
0.35
Peak Lateral Inflow (cfs)..............................................................................
0.35
Peak Outflow (cfs)........................................................................................
0.51
Peak Exfiftration Flow Rate (cfm).................................................................
0.00
Max HGL Elevation Attained (ft)...................................................................
3076.01
Max HGL Depth Attained (ft)........................................................................
4.01
Average HGL Elevation Attained (ft)............................................................
3074.50
Average HGL Depth Attained (ft).................................................................
2.5
Time of Max HGL Occurrence (days hh:mm)..............................................
0 0457
Total Exfiltration Volume (1000-ft')..............................................................
0.000
Total Flooded Volume (ac-in).......................................................................
0
Total Time Flooded (min).............................................................................
0
Total Retention Time (sec)...........................................................................
0.00

Post -construction 1 Year, 24 Hour
BREC, P.A. Brown Apartments 13

Project Description
File Name ....................................................
POST-CON-ROUTING.SPF
Project Options
Flow Units ...................................................
CFS
Elevation Type ............................................
Elevation
Hydrology Method .......................................
SCS TR-55
Time of Concentration (TOC) Method ........
User -Defined
Link Routing Method ...................................
Hydrodynamic
Enable Overflow Ponding at Nodes ............
YES
Skip Steady State Analysis Time Periods ...
YES
Analysis Options
Start Analysis On ........................................
Feb 09, 2021
000000
End Analysis On ..........................................
Feb 11, 2021
000000
Start Reporting On ......................................
Feb 09, 2021
000000
Antecedent Dry Days ..................................
0
days
Runoff (Dry Weather) Time Step ................
0 01:0000
days hh:mm:ss
Runoff (Wet Weather) Time Step ...............
0000500
days hh:mm:ss
Reporting Time Step ...................................
0000005
days hh:mm:ss
Routing Time Step ......................................
5
seconds
Number of Elements
Qty
RainGages .................................................
1
Subbas in s....................................................
1
Nodes...........................................................
4
Junctions
1
Outfalls
1
Flow Diversions
0
Inlets
0
Storage Nodes
2
Links.............................................................
4
Channels
0
Pipes
1
Pumps
0
Orifices
1
Weirs
1
Outlets
1
Pollutants....................................................
0
LandUses ...................................................
0
Rainfall Details
SN Rain Gage Data Data Source
Rainfall
Rain State County Return Rainfall Rainfall
ID Source ID
Type
Units Period Depth Distribution
(years) (inches)
1 BOONE Time Series 1YR-24HR
Cumulative
inches North Carolina Watauga 1 3.72 SCS Type II 24-hr

Subbasin Summary
SN Subbasin Area Peak Rate Weighted Total Total Total Peak Time of
ID Factor Curve Rainfall Runoff Runoff Runoff Concentration
Number Volume
(ac) (in) (in) (ac-in) (cfs) (days hh:mm:ss)
1 POST-CON:1 0.17 484.00 98.00 3.72 3.48 0.58 0.81 0 00:05:00

Node Summary
SIN Element
Element
Invert Ground/Rim
Initial Surcharge Ponded Peak Max HGL
Max
Min
Time of Total
ID
Type
Elevation
(Max)
Water Elevation
Area Inflow Elevation
Surcharge Freeboard
Peak Flooded
Elevation
Elevation
Attained
Depth
Attained
Flooding Volume
Attained
Occurrence
(ft)
(ft)
(ft) (ft)
(ft') (cfs) (ft)
(ft)
(ft)
(days hh:mm) (ac-in)
1 SCM-OUTLET
Junction
3071.75
3079.00
3071.75 0.00
0.00 0.81 3072.06
0.00
6.94
0 0000 0.00
2 OUTFALL
Outtall
3071.50
0.81 3071.73
3 SAND -CHAMBER
Storage Node
3074.00
3077.50
3074.00
0.00 0.81 3076.35
0.00
4 SEDIMENT -CHAMBER Storage Node
3072.00
3077.50
3074.25
0.00 0.81 3076.36
0.00

Total Time
Flooded
(min)
0.00
0.00
0.00

N
J
ow a
� o
LL cZ
N
E N
N 1
W F
m
E
E wE
3 wo
y W —
U)
r
J
O r r
O
OO
M M M
000
000
N V V
r r r
000
M M M
Ir
w
m
2 Ir Ir
¢ww
=mm
U < <
F Q Q
Z = _
W U U
� 0 0
ozz
w¢¢
U U U

Subbasin Hydrology
Subbasin : POST-CONA
Input Data
Area(ac).....................................................
0.17
Peak Rate Factor ........................................
484.00
Weighted Curve Number ............................
98.00
Rain Gage ID ...............................................
BOONE
Composite Curve Number
Area
Soil Curve
Soil/Surface Description
(acres)
Group Number
-
0.17
- 98.00
Composite Area & Weighted CN
0.17
98.00
Subbasin Runoff Results
Total Rainfall (in) .........................................
3.72
Total Runoff (in) ..........................................
3.48
Peak Runoff (cfs)........................................
0.81
Weighted Curve Number ............................
98.00
Time of Concentration (days hh:mm:ss) .....
0 00:05:00

Subbasin : POST-CON:1
5.2
5
4.8
4.6
4.4
42
4
3.8
3.6
34
3.2
3
2.8
2.6
2.4
ry 2.2
2
1.0
16
1.4
1.2
1
08
06
0.4
0.2
0.9
0.85
0.8
0.75
0.7
0.65
0.6
0.55
N 0.5
w 0.45
o
0
Y 0.4
0 35
0.3
0.25
02
0.15
0.1
0.05
Rainfall Intensity Graph
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48
Time [hrs]
Runoff Hydrograph
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46
Time [hrs]

Junction Input
SIN Element Invert Ground/Rim Ground/Rim Initial Initial Surcharge Surcharge Ponded Minimum
ID Elevation (Max) (Max) Water Water Elevation Depth Area Pipe
Elevation Offset Elevation Depth Cover
(ft) (ft) (ft) (ft) (ft) (ft) (ft) (ft) (in)
1 SCM-OUTLET 3071.75 3079.00 7.25 3071.75 0.00 0.00-3079.00 0.00 0.00

Junction Results
SIN Element Peak Peak Max HGL Max HGL
Max
Min Average HGL Average HGL
Time of
Time of Total Total Time
ID Inflow Lateral Elevation
Depth Surcharge Freeboard
Elevation
Depth
Max HGL
Peak Flooded Flooded
Inflow Attained
Attained
Depth
Attained
Attained
Attained
Occurrence
Flooding Volume
Attained
Occurrence
(cfs) (cfs) (ft)
(ft)
(ft)
(ft)
(ft)
(ft)
(days hh:mm)
(days hh:mm) (ac-in) (min)
1 SCM-OUTLET 0.81 0.00 3072.06
0.31
0.00
6.94
3071.78
0.03
0 11:55
0 00:00 0.00 0.00

Pipe Input
SIN Element Length Inlet Inlet Outlet Outlet Total Average Pipe Pipe Pipe Manning's Entrance Exit/Bend Additional Initial
ID Invert Invert Invert Invert Drop Slope Shape Diameteror Width Roughness Losses Losses Losses Flow
Elevation Offset Elevation Offset Height
(ft) (ft) (ft) (ft) (ft) (ft) (%) (in) (in) (cfs)
1 SCM-OUTLET-LINK 10.00 3071.75 0.00 3071.50 0.00 0.25 2.5000 CIRCULAR 15.000 15.000 0.0120 0.5000 0.5000 0.0000 0.00

Flap No. of
Gate Barrels
No 1

Pipe Results
SN Element Peak Time of Design Flow Peak Flow/ Peak Flow Travel Peak Flow Peak Flow Total Time Froude Reported
ID Flow Peak Flow Capacity Design Flow Velocity Time Depth Depth/ Surcharged Number Condition
Occurrence Ratio Total Depth
Ratio
(cfs) (days hh:mm) (cfs) (ft/sec) (min) (ft) (min)
1 SCM-OUTLET-LINK 0.81 0 11:55 11.06 0.07 4.21 0.04 0.27 0.21 0.00 Calculated

Storage Nodes
Storage Node : SAND -CHAMBER
Input Data
Invert Elevation (ft).......................................................................................
3074.00
Max (Rim) Elevation (ft)...............................................................................
3077.50
Max (Rim) Offset (ft)....................................................................................
3.50
Initial Water Elevation (ft).............................................................................
3074.00
Initial Water Depth (ft)..................................................................................
0.00
Ponded Area (ft')..........................................................................................
0.00
EvaporationLoss.........................................................................................
0.00
Storage Area Volume Curves
Storage Curve : SAND -CHAMBER
Stage Storage Storage
Area Volume
0 104 0.000
2.5 104 260.00
2.6 1 265.25
3.6 1 266.25

2
2
2
2
2
2
2
2
2
0
0
0
0
0
0
0
0
0
Storage Area Volume Curves
Storage Volume (ft)
0 40 20 30 40 50 60 70 80 90 100 110 420 430 140 450 460 170 180 490 200 240 220 230 240 260 260
6----,----------------------------------------------------------------------------- v---------------- - - ---
3.6
5---------------- --------- ------------------------ --- ------- -- - - 3.5
4 ---i------ --i---r---7------- i------- ------------------------------- 7 - - - 7-------------- ------ 3.4
3--- '----------- •---'---`---`------- '--- '---`---`-- - - - - 3.3
2 --- --- - -- - -- --- --- --- --- ------ --- --- --- --- - ------ - - - - -- - -- - -- - -- - -- --- --- -- - --- -- 3.2
7---'---'---'---•---'---`---`---`-- '--- '---`---`-- - - - - 3.1
3 --- - -- - -- - -- - -- --- --- --- - - -- -- --- --- --- --- ------- - - - - -- --- - -- - -- --- - -- - -- - - -- -- -- 3
9 ---'---'---'--- I-------`---`---`-- - - - - 2.9
8 - -- *- - - * - -- -- -- - ------------- --- --- --- --- --- --- ------ -- 2.8
6----- -- ------ --- --- --- --- --- --- ------ - 2.6
4 *---*--- -- -- - --- ------------- --- --- --- --- --- --- -- -- 2.4
3-- - - - - -- - ----------------------------------------------------- - - - - ------------ 2.3
2'---"--------'---------------'---'-- '---"---"---'---'--- - - - - 2.2
7-- - - - - -- - - -------------------------------------------- - - -- -------------- ------ 2.1
2 - - - ................................. - - - 2
9-------- - --------------------------------------------------------------------- 1.9
8 ------------------------------------ - - - - 7.8
6---------*--- --------------�--- --- ---- ---- --- --- --- --- --- --- ------ -- 7.6
5-- - - - - -- - - -- ------------------- - - -- --------------------------------------- - - - -- 7.5
4'---"---"---"---'---•---•---'---'-- -----I'---"---'--- - - - - 1.4
3;---;---'---'---;---'---;---;----I--- ------------------------------- 7.3
2---'---'---'---•--- `---`---`-- '---'---'--`---`-- - - - - 1.2
7 --- --- --- - -- - -- - -- --- --- - - -- -- - -- - - -- --- - ---------- -- --- - -- - -- - -- ---
--- ------ -- 7.7
9-
------------- ---- ------- - - -- -- ,---,---,------------ ,---,---.---.------ 0.9
7---- ;--- ;- - -T--- -- - -- ;--- ;- - - - - -- - --- -------- --- --- --- --- -- - --- -- 0.7
5 ---------- - -- - -- -- -- ;---;---;-- --- ------- - - -- -- I--- --- --- --- --- - -- - - - --- -- 0.5
3 ;---;-- T--- -- -- ----------- --- ------------- --- --- --- --- --- --- ------ -- 0.3
2--------------------------------------------------------------- 4.2
7 -- ------*--- --- -- --- ------�--- ------------- --- --- --- --- --- --- ------ -- 0.1
4 4
5 40 75 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
Storage Area (ft)
Storage Area — Storage Volume

Storage Node : SAND -CHAMBER (continued)
Outflow Weirs
SIN Element Weir Flap Crest Crest Length Weir Total Discharge
ID Type Gate Elevation Offset Height Coefficient
(ft) (ft) (ft) (ft)
1 EM-SPILLWAY Rectangular No 3076.25 2.25 8.00 0.25 3.33
Output Summary Results
Peak Inflow (cfs)..........................................................................................
0.81
Peak Lateral Inflow (cfs)..............................................................................
0.00
Peak Outflow (cfs)........................................................................................
0.81
Peak Exfiftration Flow Rate (cfm).................................................................
0.00
Max HGL Elevation Attained (ft)...................................................................
3076.35
Max HGL Depth Attained (ft)........................................................................
2.35
Average HGL Elevation Attained (ft)............................................................
3075.05
Average HGL Depth Attained (ft).................................................................
1.05
Time of Max HGL Occurrence (days hh:mm)..............................................
0 11:55
Total Exfiltration Volume (1000-ft3)..............................................................
0.000
Total Flooded Volume (ac-in).......................................................................
0
Total Time Flooded (min).............................................................................
0
Total Retention Time (sec)...........................................................................
0.00

Storage Node : SEDIMENT -CHAMBER
Input Data
Invert Elevation (ft).......................................................................................
3072.00
Max (Rim) Elevation (ft)...............................................................................
3077.50
Max (Rim) Offset (ft)....................................................................................
5.50
Initial Water Elevation (ft).............................................................................
3074.25
Initial Water Depth (ft)..................................................................................
2.25
Ponded Area (ft2)..........................................................................................
0.00
EvaporationLoss.........................................................................................
0.00
Storage Area Volume Curves
Storage Curve : SEDIMENT -CHAMBER
Stage
Storage
Storage
Area
Volume
(ft)
(ft2)
(ft')
0
128
0.000
4.5
128
576.00
4.6
1
582.45
5.6
1
583.45

Storage Area Volume Curves
S101a9e Volume (ft)
0 50 100 150 200 250 300 360 400 460 600 660
G.6
5.6
G.4--------------------
'--------'--------•--------'--------'--------- '---------------------------------------------
6.4
1.2
---------- ---------- --------'-----------------`--------'---------'--------'--------'--------'--------------
5.2
6
------- ----- ------ ------ ------ ----- ----- ----- ----- ------ ------ ----
5
66
'--------'--------'-------- `-------- '--------- '------------------'--------'--------`-----
4.6
64
------------------------- --
4.4
4
-------- -------- -------- -------- -------- ------------------------- -------- -------- ------ -----
4
1.6
'-------- '--------'--------'--------'--------`-------- '--------- -------- '--------'----- --------- -----
3.6
1.6
; ; ;-- - - - - -� -----
3.6
1.4
'---------- --------'--------'-----------------`--------'---------'--------'------'-----------------------
3.4
1.2
-------------------------------------------------------------------- --------------------------------
3.2
3
---------------------------------------------------------------------------------------------------
3
!.8
-----------------------------------------------------------------------------------------------------
2.8
!.6
-----------------'--------'------------------------------------------------------------------ ------
2.6
!.4------------------------------------------------
-----------------------------------4---------------
2.4
!.2
-------------------'--------'------------------------------------------------------------------ ------
2.2
2
----- ----- ------ ------ ------ ----- ----- ----- ----- ------ ------ ----
2
I.6
'--------'--------'--------'--------'-------`--------'---------'--------'--------'--------'--------`-----
1.6
1
-------- -------- -- --- -------- -------- ------------------------- -------- -------- -------- -----
1
1.6
-------- '--------�------- '--------'--------`-------- '--------- '-------- '--------'--------'-------- -----
0.6
1.6
;- - -- - - -; ; � - - - --
0.6
1.4
----------------'--------'--------f--------------------------------------------'----------------------
4.4
1.2----
---------------------------------------------------------------------------------------------
0.2
0
0
0 5 10 15 20 25 30 35 40 45 50 65 60 65 70 76 80 85 90 95 100 105 110 115 120 125
Storage Area (ft)
Storage Area - Storage Volume

Storage Node : SEDIMENT -CHAMBER (continued)
Outflow Orifices
SN Element Orifice Orifice Flap Circular Rectangular Rectangular Orifice Orifice
ID Type Shape Gate Orifice Orifice Orifice Invert Coefficient
Diameter Height Width Elevation
(in) (in) (in) (ft)
1 CHAMBER -CONNECTION Side CIRCULAR No 15.00 3074.00 0.61
Output Summary Results
Peak Inflow (cfs)..........................................................................................
0.81
Peak Lateral Inflow (cfs)..............................................................................
0.81
Peak Outflow (cfs)........................................................................................
0.81
Peak Exfiftration Flow Rate (cfm).................................................................
0.00
Max HGL Elevation Attained (ft)...................................................................
3076.36
Max HGL Depth Attained (ft)........................................................................
4.36
Average HGL Elevation Attained (ft)............................................................
3075.05
Average HGL Depth Attained (ft).................................................................
3.05
Time of Max HGL Occurrence (days hh:mm)..............................................
0 11:55
Total Exfiltration Volume (1000-ft')..............................................................
0.000
Total Flooded Volume (ac-in).......................................................................
0
Total Time Flooded (min).............................................................................
0
Total Retention Time (sec)...........................................................................
0.00

Post -construction 100 Year, 24 Hour
BREC, P.A. Brown Apartments 14

Project Description
File Name ....................................................
POST-CON-ROUTING.SPF
Project Options
Flow Units ....................................................
CFS
Elevation Type .............................................
Elevation
Hydrology Method ........................................
SCS TR-55
Time of Concentration (TOC) Method .........
User -Defined
Link Routing Method ....................................
Hydrodynamic
Enable Overflow Ponding at Nodes .............
YES
Skip Steady State Analysis Time Periods ....
YES
Analysis Options
Start Analysis On .........................................
Feb 09, 2021
000000
End Analysis On ..........................................
Feb 11, 2021
000000
Start Reporting On .......................................
Feb 09, 2021
000000
Antecedent Dry Days ...................................
0
days
Runoff (Dry Weather) Time Step .................
0 01:0000
days hh:mm:ss
Runoff (Wet Weather) Time Step ................
0000500
days hh:mm:ss
Reporting Time Step ....................................
0000005
days hh:mm:ss
Routing Time Step .......................................
5
seconds
Number of Elements
Qty
RainGages ..................................................
1
Subbas in s.....................................................
1
Nodes...........................................................
4
Junctions
1
Outfalls
1
Flow Diversions
0
Inlets
0
Storage Nodes
2
Links.............................................................
4
Channels
0
Pipes
1
Pumps
0
Orifices
1
Weirs
1
Outlets
1
Pollutants.....................................................
0
LandUses ....................................................
0
Rainfall Details
SN Rain Gage Data Data Source
Rainfall
Rain State County Return Rainfall Rainfall
ID Source ID
Type
Units Period Depth Distribution
(years) (inches)
1 BOONE Time Series 100YR-24HR Cumulative
inches North Carolina Watauga 100 10.90 SCS Type II 24-hr

Subbasin Summary
SN Subbasin Area Peak Rate Weighted Total Total Total Peak Time of
ID Factor Curve Rainfall Runoff Runoff Runoff Concentration
Number Volume
(ac) (in) (in) (ac-in) (cfs) (days hh:mm:ss)
1 POST-CON:1 0.17 484.00 98.00 10.90 10.66 1.78 2.39 0 00:05:00

Node Summary
SIN Element
Element
Invert Ground/Rim
Initial Surcharge Ponded Peak Max HGL
Max
Min
Time of Total
ID
Type
Elevation
(Max)
Water Elevation
Area Inflow Elevation
Surcharge Freeboard
Peak Flooded
Elevation
Elevation
Attained
Depth
Attained
Flooding Volume
Attained
Occurrence
(ft)
(ft)
(ft) (ft)
(ft') (cfs) (ft)
(ft)
(ft)
(days hh:mm) (ac-in)
1 SCM-OUTLET
Junction
3071.75
3079.00
3071.75 0.00
0.00 2.39 3072.34
0.00
6.66
0 0000 0.00
2 OUTFALL
Outtall
3071.50
2.39 3071.89
3 SAND -CHAMBER
Storage Node
3074.00
3077.50
3074.00
0.00 2.39 3076.45
0.00
4 SEDIMENT -CHAMBER Storage Node
3072.00
3077.50
3074.25
0.00 2.39 3076.61
0.00

Total Time
Flooded
(min)
0.00
0.00
0.00

N
J
ow a
� o
LL cZ
N
E N
N 1
W F
m
E
E wE
3 wo
y W —
U)
r
J
O r r
O
OO
M M M
000
000
N V V
r r r
000
M M M
Ir
w
m
2 Ir Ir
¢ww
=mm
U < <
F Q Q
Z = _
W U U
� 0 0
ozz
w¢¢
U U U

Subbasin Hydrology
Subbasin : POST-CONA
Input Data
Area(ac).....................................................
0.17
Peak Rate Factor ........................................
484.00
Weighted Curve Number ............................
98.00
Rain Gage ID ...............................................
BOONE
Composite Curve Number
Area
Soil Curve
Soil/Surface Description
(acres)
Group Number
-
0.17
- 98.00
Composite Area & Weighted CN
0.17
98.00
Subbasin Runoff Results
Total Rainfall (in) .........................................
10.90
Total Runoff (in) ..........................................
10.66
Peak Runoff (cfs)........................................
2.39
Weighted Curve Number ............................
98.00
Time of Concentration (days hh:mm:ss) .....
0 00:05:00

Subbasin : POST-CON:1
15
14.5
14
13.5
13
12.5
12
11.5
11
10.5
10
9.5
9
8.5
� 8
7.5
-E 7
6.5
r 6
5.5
5
4.5
4
3.5
3
2.5
2
1.5
1
0.5
2.5
24
2.3
2.2
2.1
2
19
1.8
1.7
16
1.5
N 1.4
'--- 1 3
1.2
ry 1.1
1
0.9
0.0
0.7
0.6
0.5
0.4
0.3
0.2
0.1
Rainfall Intensity Graph
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48
Time [hrs]
Runoff Hydrograph
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46
Time [hrs]

Junction Input
SIN Element Invert Ground/Rim Ground/Rim Initial Initial Surcharge Surcharge Ponded Minimum
ID Elevation (Max) (Max) Water Water Elevation Depth Area Pipe
Elevation Offset Elevation Depth Cover
(ft) (ft) (ft) (ft) (ft) (ft) (ft) (ft) (in)
1 SCM-OUTLET 3071.75 3079.00 7.25 3071.75 0.00 0.00-3079.00 0.00 0.00

Junction Results
SIN Element Peak Peak Max HGL Max HGL
Max
Min Average HGL Average HGL
Time of
Time of Total Total Time
ID Inflow Lateral Elevation
Depth Surcharge Freeboard
Elevation
Depth
Max HGL
Peak Flooded Flooded
Inflow Attained
Attained
Depth
Attained
Attained
Attained
Occurrence
Flooding Volume
Attained
Occurrence
(cfs) (cfs) (ft)
(ft)
(ft)
(ft)
(ft)
(ft)
(days hh:mm)
(days hh:mm) (ac-in) (min)
1 SCM-OUTLET 2.39 0.00 3072.34
0.59
0.00
6.66
3071.79
0.04
0 11:55
0 00:00 0.00 0.00

Pipe Input
SIN Element Length Inlet Inlet Outlet Outlet Total Average Pipe Pipe Pipe Manning's Entrance Exit/Bend Additional Initial
ID Invert Invert Invert Invert Drop Slope Shape Diameteror Width Roughness Losses Losses Losses Flow
Elevation Offset Elevation Offset Height
(ft) (ft) (ft) (ft) (ft) (ft) (%) (in) (in) (cfs)
1 SCM-OUTLET-LINK 10.00 3071.75 0.00 3071.50 0.00 0.25 2.5000 CIRCULAR 15.000 15.000 0.0120 0.5000 0.5000 0.0000 0.00

Flap No. of
Gate Barrels
No 1

Pipe Results
SN Element Peak Time of Design Flow Peak Flow/ Peak Flow Travel Peak Flow Peak Flow Total Time Froude Reported
ID Flow Peak Flow Capacity Design Flow Velocity Time Depth Depth/ Surcharged Number Condition
Occurrence Ratio Total Depth
Ratio
(cfs) (days hh:mm) (cfs) (ft/sec) (min) (ft) (min)
1 SCM-OUTLET-LINK 2.39 0 11:55 11.06 0.22 5.34 0.03 0.49 0.39 0.00 Calculated

Storage Nodes
Storage Node : SAND -CHAMBER
Input Data
Invert Elevation (ft).......................................................................................
3074.00
Max (Rim) Elevation (ft)...............................................................................
3077.50
Max (Rim) Offset (ft)....................................................................................
3.50
Initial Water Elevation (ft).............................................................................
3074.00
Initial Water Depth (ft)..................................................................................
0.00
Ponded Area (ft')..........................................................................................
0.00
EvaporationLoss.........................................................................................
0.00
Storage Area Volume Curves
Storage Curve : SAND -CHAMBER
Stage Storage Storage
Area Volume
0 104 0.000
2.5 104 260.00
2.6 1 265.25
3.6 1 266.25

2
2
2
2
2
2
2
2
2
0
0
0
0
0
0
0
0
0
Storage Area Volume Curves
Storage Volume (ft)
0 40 20 30 40 50 60 70 80 90 100 110 420 430 140 450 460 170 180 490 200 240 220 230 240 260 260
6----,----------------------------------------------------------------------------- v---------------- - - ---
3.6
5---------------- --------- ------------------------ --- ------- -- - - 3.5
4 ---i------ --i---r---7------- i------- ------------------------------- 7 - - - 7-------------- ------ 3.4
3--- '----------- •---'---`---`------- '--- '---`---`-- - - - - 3.3
2 --- --- - -- - -- --- --- --- --- ------ --- --- --- --- - ------ - - - - -- - -- - -- - -- - -- --- --- -- - --- -- 3.2
7---'---'---'---•---'---`---`---`-- '--- '---`---`-- - - - - 3.1
3 --- - -- - -- - -- - -- --- --- --- - - -- -- --- --- --- --- ------- - - - - -- --- - -- - -- --- - -- - -- - - -- -- -- 3
9 ---'---'---'--- I-------`---`---`-- - - - - 2.9
8 - -- *- - - * - -- -- -- - ------------- --- --- --- --- --- --- ------ -- 2.8
6----- -- ------ --- --- --- --- --- --- ------ - 2.6
4 *---*--- -- -- - --- ------------- --- --- --- --- --- --- -- -- 2.4
3-- - - - - -- - ----------------------------------------------------- - - - - ------------ 2.3
2'---"--------'---------------'---'-- '---"---"---'---'--- - - - - 2.2
7-- - - - - -- - - -------------------------------------------- - - -- -------------- ------ 2.1
2 - - - ................................. - - - 2
9-------- - --------------------------------------------------------------------- 1.9
8 ------------------------------------ - - - - 7.8
6---------*--- --------------�--- --- ---- ---- --- --- --- --- --- --- ------ -- 7.6
5-- - - - - -- - - -- ------------------- - - -- --------------------------------------- - - - -- 7.5
4'---"---"---"---'---•---•---'---'-- -----I'---"---'--- - - - - 1.4
3;---;---'---'---;---'---;---;----I--- ------------------------------- 7.3
2---'---'---'---•--- `---`---`-- '---'---'--`---`-- - - - - 1.2
7 --- --- --- - -- - -- - -- --- --- - - -- -- - -- - - -- --- - ---------- -- --- - -- - -- - -- ---
--- ------ -- 7.7
9-
------------- ---- ------- - - -- -- ,---,---,------------ ,---,---.---.------ 0.9
7---- ;--- ;- - -T--- -- - -- ;--- ;- - - - - -- - --- -------- --- --- --- --- -- - --- -- 0.7
5 ---------- - -- - -- -- -- ;---;---;-- --- ------- - - -- -- I--- --- --- --- --- - -- - - - --- -- 0.5
3 ;---;-- T--- -- -- ----------- --- ------------- --- --- --- --- --- --- ------ -- 0.3
2--------------------------------------------------------------- 4.2
7 -- ------*--- --- -- --- ------�--- ------------- --- --- --- --- --- --- ------ -- 0.1
4 4
5 40 75 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
Storage Area (ft)
Storage Area — Storage Volume

Storage Node : SAND -CHAMBER (continued)
Outflow Weirs
SIN Element Weir Flap Crest Crest Length Weir Total Discharge
ID Type Gate Elevation Offset Height Coefficient
(ft) (ft) (ft) (ft)
1 EM-SPILLWAY Rectangular No 3076.25 2.25 8.00 0.25 3.33
Output Summary Results
Peak Inflow (cfs)..........................................................................................
2.39
Peak Lateral Inflow (cfs)..............................................................................
0.00
Peak Outflow (cfs)........................................................................................
2.39
Peak Exfiftration Flow Rate (cfm).................................................................
0.00
Max HGL Elevation Attained (ft)...................................................................
3076.45
Max HGL Depth Attained (ft)........................................................................
2.45
Average HGL Elevation Attained (ft)............................................................
3075.35
Average HGL Depth Attained (ft).................................................................
1.35
Time of Max HGL Occurrence (days hh:mm)..............................................
0 11:55
Total Exfiltration Volume (1000-ft3)..............................................................
0.000
Total Flooded Volume (ac-in).......................................................................
0
Total Time Flooded (min).............................................................................
0
Total Retention Time (sec)...........................................................................
0.00

Storage Node : SEDIMENT -CHAMBER
Input Data
Invert Elevation (ft).......................................................................................
3072.00
Max (Rim) Elevation (ft)...............................................................................
3077.50
Max (Rim) Offset (ft)....................................................................................
5.50
Initial Water Elevation (ft).............................................................................
3074.25
Initial Water Depth (ft)..................................................................................
2.25
Ponded Area (ft2)..........................................................................................
0.00
EvaporationLoss.........................................................................................
0.00
Storage Area Volume Curves
Storage Curve : SEDIMENT -CHAMBER
Stage
Storage
Storage
Area
Volume
(ft)
(ft2)
(ft')
0
128
0.000
4.5
128
576.00
4.6
1
582.45
5.6
1
583.45

Storage Area Volume Curves
S101a9e Volume (ft)
0 50 100 150 200 250 300 360 400 460 600 660
G.6
5.6
G.4--------------------
'--------'--------•--------'--------'--------- '---------------------------------------------
6.4
1.2
---------- ---------- --------'-----------------`--------'---------'--------'--------'--------'--------------
5.2
6
------- ----- ------ ------ ------ ----- ----- ----- ----- ------ ------ ----
5
66
'--------'--------'-------- `-------- '--------- '------------------'--------'--------`-----
4.6
64
------------------------- --
4.4
4
-------- -------- -------- -------- -------- ------------------------- -------- -------- ------ -----
4
1.6
'-------- '--------'--------'--------'--------`-------- '--------- -------- '--------'----- --------- -----
3.6
1.6
; ; ;-- - - - - -� -----
3.6
1.4
'---------- --------'--------'-----------------`--------'---------'--------'------'-----------------------
3.4
1.2
-------------------------------------------------------------------- --------------------------------
3.2
3
---------------------------------------------------------------------------------------------------
3
!.8
-----------------------------------------------------------------------------------------------------
2.8
!.6
-----------------'--------'------------------------------------------------------------------ ------
2.6
!.4------------------------------------------------
-----------------------------------4---------------
2.4
!.2
-------------------'--------'------------------------------------------------------------------ ------
2.2
2
----- ----- ------ ------ ------ ----- ----- ----- ----- ------ ------ ----
2
I.6
'--------'--------'--------'--------'-------`--------'---------'--------'--------'--------'--------`-----
1.6
1
-------- -------- -- --- -------- -------- ------------------------- -------- -------- -------- -----
1
1.6
-------- '--------�------- '--------'--------`-------- '--------- '-------- '--------'--------'-------- -----
0.6
1.6
;- - -- - - -; ; � - - - --
0.6
1.4
----------------'--------'--------f--------------------------------------------'----------------------
4.4
1.2----
---------------------------------------------------------------------------------------------
0.2
0
0
0 5 10 15 20 25 30 35 40 45 50 65 60 65 70 76 80 85 90 95 100 105 110 115 120 125
Storage Area (ft)
Storage Area - Storage Volume

Storage Node : SEDIMENT -CHAMBER (continued)
Outflow Orifices
SN Element Orifice Orifice Flap Circular Rectangular Rectangular Orifice Orifice
ID Type Shape Gate Orifice Orifice Orifice Invert Coefficient
Diameter Height Width Elevation
(in) (in) (in) (ft)
1 CHAMBER -CONNECTION Side CIRCULAR No 15.00 3074.00 0.61
Output Summary Results
Peak Inflow (cfs)..........................................................................................
2.39
Peak Lateral Inflow (cfs)..............................................................................
2.39
Peak Outflow (cfs)........................................................................................
2.39
Peak Exfiftration Flow Rate (cfm).................................................................
0.00
Max HGL Elevation Attained (ft)...................................................................
3076.61
Max HGL Depth Attained (ft)........................................................................
4.61
Average HGL Elevation Attained (ft)............................................................
3075.35
Average HGL Depth Attained (ft).................................................................
3.35
Time of Max HGL Occurrence (days hh:mm)..............................................
0 11:55
Total Exfiltration Volume (1000-ft')..............................................................
0.000
Total Flooded Volume (ac-in).......................................................................
0
Total Time Flooded (min).............................................................................
0
Total Retention Time (sec)...........................................................................
0.00