HomeMy WebLinkAbout17 - Design Report - JC Billion Auto Plaza Lot 2A Block 1 - Stormwater ENGINEERING
AM-'NEt5ls CONSULTING
ly p�� + �« ( + PLANNING
NGINEERCNG, INC DESIGN
204 N.1 lmC BOZEMAN,NT 59715 a0G-581 is 19 ,w.w.g-e-1,net
Storm Water Design Report
Table Contents
1. Report
2. Basin Map
3. Outlet Structure Calculations
4. C Coefficient
5. Time of Concentration Calculations
6. Weighted C
7. Rational Method Calculations
8. Pond Size Calculations
204 N. 1 V"Ave., Bozeman,MT 59715 Cell:(406)581-3319 www,q-e-Lnet Page 1 of 1
ENGINEERING
f 4 E AW*,I CONSULTING
PLANNING
NGNE&RING, INC DESIGN
204 N.11'Ave. P ZEMIAN,MT 59715 406-581- 319 • ww.V.g-e-,net
November 9, 2017 �.
Re: Stormwater Design Amended Plat-J.C. Billion Auto Plaza Subdivision -Lot 2A Block 1
I. Existing Conditions
The site consists of developed lots with grassland, pavement, and gravel. The land slopes generally
to the north at a grade of approximately 1.5% with the high point of the property located on the
southeastern corner of the subdivision. The natural grading conveys runoff in an overland fashion, to
Baxter Creek that lies just west of the site. The existing Lots all have their own respective storm
attenuation pond with the exception of Lot 2A, Block 1. This can be seen on the attached exhibit
showing the existing ponds and proposed drainage basins. The Billion Reconditioning Building will be
located on Lot 2A, Block 1. The purpose of this design report is to size and design the attenuation
storm pond for the areas that are to develop and do not have a storm attenuation pond identified.
Drainage Basins and Pre-development Peak Flows
Drainage basins were identified for the site. Basin A is comprised of Lot 2A, while Basins B1 and B2
encompass the existing roads within the J.C. Billion Auto Plaza Subdivision. Basin C is a combination
of Basin A and Basin B1. Estimates of runoff and their respective calculations for the existing
subareas were completed using the Modified Rational Method. The 10-year, 25-year, and 100-year
storm events were used in the analysis of the existing storm water, conveyance facilities within the
site. A summary of estimated pre-development peak runoff rates can be found in Table 1.
Table 1. Estimated Pre-Development Peak Flows (see basin map)
Sub Area Description Area C Tc Q10 Q25 Q100
tacres} (mint (cfis) tcfsl (cfsl
Basin A Lot 2A Block 1 2.9 0.20 20 0.8 0.9 1.2
Basin B1 Half Auto Plaza&Comp Dr. 0.8 0.20 28.3 0.2 0.2 0.3
Basin B2 Half Auto Plaza&Comp Dr. 0.9 0.20 28.3 0.2 0.2 0.3
Basin C Sub Area A&B1 3.7 0.20 28.3 0.8 0.9 1,2
Ii. Proposed Drainage Plan and Estimated Post-Development Peak Flows
The proposed drainage plan consists of a new detention pond, Pond 1, and a network of inlets, pipes
and a swale that are connected and act as one pond, located at the North West corner of Lot 2A.
Basin B2 will drain into the existing storm pond that was created to detain runoff from Competition
Drive and Auto Plaza Drive. A 12' storm main will convey runoff from Basin B1 into Pond 1 via a curb
inlet on Competition Drive. The improved Lot 2A will drain into Pond 1 and the storm swale through
curb cuts in the parking lot and are tied together with a 12" storm main. Runoff will then leave Pond
1 through the outlet structure and into the 15" storrn rnain or discharge pipe that daylights at the
natural drainage on the west property line. All storm main uses a 25-yr design storm event while the
detention Pond 1 is design for the 10-year storm event and the existing pond is sized to
appropriately detain the 10-year storm event.
204 N. 1111 Ave.,Bozeman,MT 59715 Cell:(406)581-3319 wL Lg-e-i.net Page 1 of 2
l
NGtN�>ti�1PIG,I�t�
Table 2. Estimated Post-Development Peak Flows (see basin map)
Sub Area Description Area C Tc Q10 Q25 Q100
(acres) fmin) fcfs) fcfs) (cfs)
Basin A Lot 2A Block 1 2.9 0.75 13.8 3.7 4.4 5,9
Basin B1 Half Auto Plaza&Comp Dr. 0.8 0.68 15 0.9 1.0 1.4
Basin B2 Half Auto Plaza&Comp Dr. 0.9 0.64 15 1.0 1.2 1.6
Basin C A&B1 3.7 0.74 15 4.4 5.2 7.0
Table 3. Proposed Structure Capacities
Structure Slope Location Contributing QCap Q25post Passes Design
-- (%) Subareas (cfs) (cfs) Storm
Inlets NA Competition Dr'. Basin Bl 5.0 1.0 Yes
12"Storm Main 1.0% Competition Dr. Basin B1 3.3 1.0 Yes
Inlet NA Lot 2A Block 1 %Basin A 5.0 2.2 Yes
12"Storm Main 1.0% Lot 2A Block 1 Y.Basin A 3.3 2.2 Yes
Pond Outlet 15" 0.4% Lot 2A Block 1 Basin C 5.2 5.2. Yes
12"Curb Chase 1.0% Competition Dr. Basin B2 1.6 1.2 Yes
Table 4. Estimated Pond Volume
Required Actual
Pond Contributing Q10Pre Q25post Qrelease Volume Volume
Subareas (cfs) (cfs) (cfs) (cf0 (cft)
Pond 1..Detention Basin C 0.8 5.2 0.8 3,180 3,000
Storm Swale,Inlets&Piping(connected) Basin A 1.0 6.7 1.0 3,1.80 200
Total .'00
Ex Pond Comp Orive Basin B2 0.2 1.2 0.2 b 3 2 11.44
H:\1134\004\DOCS\Design\Storm\Stormwater DM.doc
4 204 N. 11"Ave., Bozeman; MT 59715 Cell: (406)581-3319 www.p-e-i.net Page 2 of 2
LEGEND:
PROPOSED POND 1 IN OUTLOT /
BASIN A _ - RECIEVES LOT 2A BLOCK 1 AND STREET
FLOW FROM HALF OF COMPETITION
BASIN B-1 �- _ ,= AND AUTO PLAZA DRIVE ;, _ -, EXISTING POND FOR COMPETITION DRIVE
BASIN -2 APPROXIMATE BOUNDARY.'
BASIN C BASIN A 8 BASIN B-1
,r.
-_ - - --- ---- - --- --- ------
�- _ /
- / ' ' EXI8TING STORM POND; -
I �
--- --- - --�/ - = �,-- �- --,I ---- -- -- -- -- -- - --- �p
z
O
i
I
PR�OSED STORM SWALE IN LOT 2A BLOCK 1 /
__// U STORM POND I
,/RELIEVES RUNOFF FROM PARKING LOT IN �I- FUTURE T I
LOT2ABLOCK1_".____-_ Y P FOR LOT IABLOCK3 I I
I I
JL
� //� �v1 ; '• \-" - _----"-' -""---"-- _ -- ----- EXISTING PARKING LOT \\\ -h-_ � LOT 2A
BASINA JI I BLOCK3
(2.9 ACRES)
I I I 0rn
., n
EXISTING BUILDING '
�I // -
\ EXISTING BUILDING I
--BLOT 1
�� \V BLOCKI %/ ----I----
\I \\ \\ \ o c DRIVE (0.8 ACRES)
\\ \\ \\ \\ a= AUTO PLA7J+
y
EXISTING
\1 , _ ILDING
i�
B1I �
\ LOT3
✓/ // /i ii `/ EXISTING PARKING LOT I ��� \\ \ I
EXISTING
// BLOCK 3 I
/ r/ r' / -_------ I BUILDING
/i ��v �!� I I II
i
I LOT1A I T \ I I
i �// r )1 11 BLOCK2 I I \
EXISTING BUILDING - I 1 f I
I --- \ L--
I I I
I I \
EXISTING STORM POND
FOR LOT.L---------------------------- - -- - 1. - ------
--
------ - - ------ ------------- ------
L--- ---- - -"-----------
----- - ----
/ EXISTING STORM PONDS
\ II 11 %r/ \\� FOR LOT 1A BLOCK 2
COTTONWOOD ROAD
GRAPHIC SCALE
40 p 20 40
(IN FEET)
1 inch— 40 fL
11'X77":1"=80 ft
VERIFY SCALE REVISIONS DRAWN BY:JAH PROJECT NUMBER
THESE PRINTS MAY BE NO. DESCRIPTION DATE BY - Cl BY;CMW J.C.BILLION AUTO PLAZA SUBDIVISION 1134.004
REDUCED.SUS LME eELOW
MEISURES ONEINLH ON
i CMW BOZEMAN AMENDED PLAT SHEETNUMBER
ORICINu DRAmNc. j 6rgmeering APPR.BY: MT
Consulting 204 N.11th Ave.
Bozeman,MT 59715 DATE:.11/2017
Design Phone:(406)5813319 DRAWING NUMBER
MDMI SCALE pCLORDINGLY INCPlanning Q.A.REVIEW
H:\1134\004WCAD\BASINS.dwg Plotted by chdstopherwasla on 1119120178:15AM ;�' NGfNEERdard L BY: DRAINAGE BASINS EXHIBIT-1
�7f11�( eRttl O �`�� 1Q1t�0/JO OleOtilllKtlf COPYRIOIROGENESIS ENGINEERING,INC.101T DATE:
NGINEERING, INC
`" #. �e�ianxgofa94'sviStawdanfoJ'Coranaicmrxt
Billion Recon
Engineer: C. Wasia
September 27, 2017
36" Round Outlet Structure - Pond 1
10 year pre 0.8 cfs
25 year post 5.2 cfs
Using COB Weir Equation
10 yr flow through slot = CLHA(3/2)
Q= 3.33*L*1.51(312) = 0.8 cfs
L = 1.57 inches
During storms greater than the 10 year, flows up to the 25 yearwill overtop the weir
and flow through the outlet pipe. Remainder of flow up to 100 year storm will leave the
pond through an armored overflow.
A
`3
91
=d
NGiNFFP n. I C
' a Br,#inning of aYmStandud of Commitment
Existing Competition Drive Pond
Engineer: C. Wasia
October 3, 2017
36" Round Outlet Structure - Pond 1
10 year pre 0.2 cfs
25 year post 1.2 cfs
Using COB Weir Equation
10 yr flow through slot = CLHA(3/2)
Q= 3.33*1-*1.5A(3/2) = 0.2 cfs
L= 0.060 ft
During storms greater than the 10 year, some additional flow will overtop the weir
and flow through the 8° PVC outlet pipe. The outlet pipe has a capacity of 1.6 cfs. Remainder of f
100 year storm will leave the pond through an existing overflow.
Typical Values for the Rational C Coefficient
(McCuen, Richard H., Hydrologic Analysis and Design, 3rd Ed.,Pearson Prentice Hall, 2005.
TABLETO Runoff Coefficients for the Rational Forniula versus Hydrologic Soil Group A,8,C-Di and
Slope Range
...........
A B C D
Lind Use 0-2% 24% 6.% C } Z-41M 6%. 2--b% 6%'
Cultivated
1,14d 0J08' OJ3 016 0,11 0,IS 0,21 (),14 0.1i) 0126 018 0,23 it 11
OJO 0.18 OZZ 0,16 0.21 0.28 0,10 0.2.5 034 0.24 0.29 0,41
Pa,ture 0,12 0,20 0.30 OAS 0.28 U7 0.24 034 0,44 ()Aj 0.40 0,50
0A5 0,25 0.37 0.23 U34 0.45 OjO (1,42 N57 0,377 0,50 0.62
TvIvadow OAO 0,16 0.21 0.14 0,22 030 0.20 0,28 0,36 0'24 0,30 0.400114 0"2 (3,31) 0.20 0.28 0,31, 01211) 0.35 0,44 0,30 0.40 0-50
Forest 0-05 0 A OJI 0.09 0.11 0.14 0.10 OA3 0.16 0,12 0,16 0,20
0,08 0,11 6,14 0.10 0.14 ),I5 0,12 (j�I(j 0.20 (;,IS 0,71-1 fiZj
Residential
lot 025 US 0,31 0.23 030 0.35 0,30 0.35 US 0,33 0.36 0,42
size 118 am OJJ 0,40 O.39 (I.,I,1 0.18 0.42 0,49 0.41 0,45 O"U
Residential
lot 01 0,26 0.29 0,24 0.29 0,31 (1,27 t0f 036 0.30 0.34 0.40
size 114 acre 030 0.314 037 0,3,1 OX,' 0.42. 0,16 OA0 0,17 0,38 0.42 0.52
Rcsidwial
lot 0.19 0,23 026 U22 0,26 030 025 0.129 0.34 0.28 '),32 0.39
size W acre 0.28 0,32 0,15 O-V 0.35 0.39 0.33 (;38 0.45 0,36 0.40 0,50
Rzsidctnial
lot (1,16 0,20 01-1 0-19 0.23 (128 0,22 0127 032 0.26 000, 0,31
size W.acre; 02 3-1 5 019 0 O.'->9 0.32 0,36 0,31 0.35 0,42 034 0.39' 0.49
R,,Aidentiel
lot 0.14 OA9 U.22 OA? 0.21 0,26 0;25 (131 0.24 0.29 0.35
sin I acre 0,22 0.20' 0,29 0,24 0.218 t 34 0,28 0.32 0,40 0.31 0.33 OA6
lodustrial 07 OAS 0,k� 0,N5 0.08 0,09 0,68 0,69 0.69 0.69
0.85 0:0 0.86 0,85 0,W3 0.86 (1,86 0,86 0.87 011a, 0.96 UM
("Anittlercial 0,71 OJI 0.72 0.71 032 0.72 0,72 02 0,72 0.72 032 0:72
0,88 0.88 0S9 0,". 0,89 0,110 U.S9 0,89 (0)o 0S9 0.89 O)a
Struts 0.71) 0.71 O:n 0.71 0.72 0,74 0,72 0:73 0,76 0,73 0,75 0.78
016 0.77 0,19 0,80 j).82 0.84 't 8 4 f1.115 ().S(.) ()4!) 11.91 095
Ofxn space 0.05 0,10 0,14 0-,qg 0,13 0,19 0.12 0,17 0.24 016 011 US
OA 1 0,10 0.20 0.14 0.0 (126 0.18 0.23 0,32 0.22 0.277 (?39
Parking, 0.85 0,86 0.87 0.85 q.,% 0,87 0,85 0.86 U7 0,8,5 i),Sb f3.87
0,95 0,96 (07 OM 0.96 097 0,95 0.96 0.97 0.95 0,96 007
'Runoff
for stornrr zurr ce iracrvalsof25 yeut�orlongor
Time of Concentration Caics
Basin Pre Past
Overland Shallow Concentrated Concentrated Flow Total Overland Shallow Concentrated Concentrated Flaw Total
(min) {min} {min} (min) {min} {min)_ .W (min) W� (min)
A 15 5.0 0 20.0 10 3.8 0 13.8
B1 15 13.3 0 28.3 S 10.0 0 15.0
B2 15 13.3 0 28.3 5 10.0 0 15.0
PONDl{C) 15 13.3 0 28.3 5 10.0 0 15,0
Detail Shop 10/3/2017
BASIN A
Weighted C
Area(st 124903
Area(Acres) 2.9
Area Impervious(0.9) 95890
Area Gravel(0.7) 3495
Area Grass(0.2) 25518
Weighted C= 0.75
BASIN'B1 BASIN B2
Weighted C Weighted C
Area(sf 35000 Area(so 41500
Area(Acres) 0.80 Area(Acres) 0.95
Area Impervious(0.9) 23920 Area Impervious(0.9) 26320
Area Gravel(0.7) 0 Area Gravel(0.7) 0
Area Grass(0.2) 11080 Area Grass(0.2) 15180
Weighted C= 0.68 Weighted C= 0.64
BASIN C (A+B-1)
Weighted C
Area(sO 159903
Area(Acres) 3.7
Area Impervious(0.9) 119810
Area Gravel(0.7) 3495
Area Grass(0.2) 36598
Weighted C= 0.74
GEI#: 1134.004
DATE: 10/3/2017
ENGINEER: Joel Horn
BASIN A- 10yr
MODIFIED RATIONAL METHOD NGINE RING, INC
Qp==CiA
a£7a N,]:Y:tvz. ,u !Acxl:a2ah,!aY'"ScY7:i. ROki"i5�;a:i�51
PRE-DEVELOPMENT
RAINFALL.FREQ 10 YR(DURATION 1) i=A`(Tc/60) " (CITY OF BOZEMAN)
BASIN AREA PRE= 2.9 AC STORM EVENT STORM i COEFF INTENSITY
YR A B IN HR
PRE-DEV Tc= 20.0 MIN 2 0.36 0.6 0.70
5 0.52 0.64 1.05
PRE-DEV C= 0.20 10 0.64 0.66 1.32
25 0.78 0.64 1.58
STORM A= 0.64 so 092 0.66 1.90
B= 0.66 100 1.01 0.67 2.11
STORM INTENSITY 1.32 IN/HR
PRE-DEV Qp= 0.77 CFS
POST-DEVELOPMENT
BASIN AREA PRE= 2.9 AC
POST-DEV Tc= 13.8 MIN
POST-DEV C= 0.75
STORM INTENSITY= 1.69 IN/HR
POST-DEV Qp= 3.67 US
H:\1134\004\DOCS\Design\Storm\Basin A1-10yr.xls 1 OF 1 PRINTED: 10/4/2017
GEI#: 1.134.004
DATE: 10/4/2017
ENGINEER: Joel Horn
BASIN A- 25yr iNESIS
MODIFIED RATIONAL METHOD NGINEERING, INC
Qp=CiA
PRE-DEVELOPMENT
RAINFALL.FREQ= 25 YR(DURATION 1) 1=A"(Tc/60) " (CITY OF BOZEMAN)
BASIN AREA PRE= 2.9 AC STORM EVENT STORM i COEFF INTENSITY
YR A 8 IN FIR
PRE-DEV Tc= 20.0 MIN - 2 0.36 0.6 0.70
S 0.52 0.64 1.05
PRE-DEV C= 0.20 10 0.64 0.66 1.32
25 0.78 0.64 1.58
STORM A= 0.78 50 092 0.66 1.90
B= 0.64 100 1.01 0.67 2.11.
STORM INTENSITY 1.58 IN/HR
PRE-DEV Qp= 0.91 CFS
POST-DEVELOPMENT
BA51N AREA PRE= 2.9 AC
POST-DEV Tc= 13.8 MIN
POST-DEV C= 075
STORM INTENSITY= 2.00 IN/HR
POST-DEV Qp= 4.35 CFS
HAI134\004\DOCS\Design\Stone\Basin A1-25yr.xls 1 OF 1 PRINTED: 10,14/2017
a
GEI##: 1134.004
DATE: 10/3/20.17
ENGINEER: Joel Horn
BASIN A- 100yr
MODIFIED RATIONAL METHOD 4� GINEE ING1 INC
Qp=CIA
2L)c N,j.Y Ayl,.. '_. Lia'rT.rtvzu.MT 5y�71`r !,{;by. $I g3f7
PRE-DEVELOPMENT
RAINFALL FREQ= 100 YR(DURATION 1) i=A*(I c/60) `' (CITY OF BOZEMAN)
BASIN AREA PRE= 2.9 AC STORM EVENT STORM i COEFF INTENSITY
YR A B IN HR
PRE-DEV Tc= 20.0 MIN 2 0.36 0.6 0,70
S 0.52 0.64 1.05
PRE-DEV C= 0.20 10 0.64 0.66 L32
'15 0.78 0.64 1.58
STORM A= 1.01 50 0.92 0.66 1,90
B= 0.67 1.00 1.01 0.67 2.1.1
STORM INTENSITY= 2.11, 1N/HR
PRE-DEV Qp= 1.22 US
POST-DEVELOPMENT
BASIN AREA PRE= 2.9 AC
POST-DEVTc= 13.8 MIN
POST-DEV C= 0,75
STORM INTENSITY= 2.70 IN/HR
POST-DEV Qp= S.88 US
HAl134\004\DOCS\Design\Storm\Basin A1-100yr.xls 1 OF 1 PRINTED: 10/4/2017
GEI#!: 1134.004
DATE: 10/3/2017
ENGINEER: Joel Horn
BASIN B1 - 10yr
MODIFIED RATIONAL METHOD NGINEERING, INC
Qp=CiA
20-N.1!'er MV - 5:1>[rfkh'.MT 53:I," _. 6LJG 53'l u£Lt9
PRE-DEVELOPMENT
RAINFALL FREQ= 10 YR(DURATION=1) i=A'(Tc/60).E (CITY OF BOZEMAN)
BASIN AREA PRE= 0.8 AC STORM EVENT STORM i COEFF INTENSITY
YR A B (IN MR)
PRE-DEV Tc= 28.3 MIN 2 0.36 0.6 O,57
5 0.52 0.64 0.84
PRE-DEV C= 0.20 10 0.64 0.66 1.05
25 0.78 0.64 1.26
STORM A= 0.64 S0 092 0.66 1.51
B= 0.66 1.00 1.01 0.67 1.67
STORM INTENSITY= 1.05 IN/HR
PRE-DEV Qp= 0.17 CFS
POST-DEVELOPMENT
BASIN AREA PRE= 0.8 AC
POST-DEV Tc= 15.0 MIN
POST-DEV C= 0.68
STORM INTENSITY= 1.60 IN/HR
POST-DEV Qp= 0.87 CFS
H:\1134\004\DOCS\Design\Storm\Basin B1-10yr.xls 1 OF 1 PRINTED 10/4/2017
GEltt: 11,34.004
DATE: 10/3/2017
ENGINEER: Joel Horn
BASIN B1 - 25yr
MODIFIED RATIONAL METHOD NGINE"RING,, INC
Qp=CiA
PRE-DEVELOPMENT
RAINFALL FREQ 25 YR(DURATION=1) i=A°(rc./60) ° (CITY OF BOZEMAN)
BASIN AREA PRE= 0.8 AC STORM EVENT STORM i COEFF INTENSITY
YR A B
PRE-DEV Tc= 28.3 MIN 2 0.36 0.6 0.57
5 0.52 0.64 0.84
PRE-DEV C= 0.20 10 0.64 0.66 1.05
2S 0.78 0.64 1.26
STORM A= 0.78 so 0.92 0.66 1.51
B= 0.64 100 1..01 0.67 1.67
STORM INTENSITY= 1.26 IN/HR
PRE-DEV Qp= 0.20 CFS
POST-DEVELOPMENT
BASIN AREA PRE= 0.8 AC
POST-DEV Tc= 15.0 MIN
POST-DI V C= 0,68
SIORMINI'ENSITY= 1.89 IN/HR
POST-DEV Qp= 1.03 CFS
H:\1134\004\DOCS\Design\Storm\Basin B1-25yr.xls 1 OF 1 PRINTED 10/4/2017
GEI#: 1134.004
DATE: 10/3/2017
ENGINEER: Joel Horn
BASIN B1 - 100yr
MODIFIED RATIONAL METHOD "Kir I" , INC
Qp=CiA
.Sti.551:,3!0
PRE-DEVELOPMENT
RAINFALL FREQ 1.00 YR(DURATION=1) i=A (Tc/60)-Er (CITY OF BOZEMAN)
BASIN AREA PRE= 0.8 AC STORM EVENT STORM i COE.FF INTENSITY
(YR) �l/a B (IN/HR
PRE-DEV Tc= 28.3 MIN 2 0.36 0.6 0,57
5 0.52 0.64 0.84
PRE-DEV C= 0.20 10 0.64 0.66 1,05
25 0.78 0.64 1.26
STORM A= 1.01 50 0.92 0.66 1.51
B= 0.67 100 1.01 0.67 1.67
STORM INTENSITY 1.67 IN/HR
PRE-DEV Qp= 0.27 CFS
POST-DEVELOPMENT
BASIN AREA PRE= 0.8 AC
POST-DEV Tc= 15.0 MIN
POST-DEV C= 0,68
STORM INTENSITY= 2.56 IN/HR
POST-DEV Qp= 1.39 CFS
H:\1134\004\DOGS\Design\Storm\Basin B1-100yr.xis 1 OF 1 PRINTED: 10/4/2017
GEM: 1134.004
DATE: 10/4/2017
ENGINEER: CMW
Basin 02 - 10 yr
MODIFIED RATIONAL METHOD
Qp=CiA
PRE-DEVELOPMENT
RAINFALL FREQ= 10 YR(DURATION=1) i=A'(Tc/60) " (CITY OF BOZEMAN)
BASIN AREA PRE= 0.95 AC STORM EVENT STORM i COEFF INTENSITY
YR A B IN HR
PRE-DEV'Tc= 28.3 MIN 2 0.36 0.6 0.57
5 0,52 0.64 0.84
PRE-DEV C= 0.20 10 0.64 0.66 1.05
25 0.78 0.64 1.26
STORM A= 0.64 50 0,92 0,66 1.51
B= 0.66 100 1.01 0.67 1.67
STORM INTENSITY_. 1..05 IN/HR
PRE-DEV Qp= 0.20 CFS
POST-DEVELOPMENT POND VOLUME: CONSTAELEASE,
�CF}
BASIN AREA POST= 0.95 AC #s32,57
POST'-DEV Tc= 15.0 MIN TRIANGLE,kucL SE
DETENTION �jC.w
POST-DEV C= 0,64 07 <
STORM INTENSIFY= 1.60 IN/HR iVER EVOLUME
POST-DEV Qp= 0.97 CFS
x7s�az
H:\1134\004\DOGS\Design\Storm\Basin B2 Pond-10yr.xls 1 OF 1 PRINTED: 10/4/2017
GEI#: 1134,004
DATE: 10/4/2017
ENGINEER: CMW
Basin B2 - 25 yr
MODIFIED RATIONAL METHOD
Qp=CiA
PRE-DEVELOPMENT
RAINFALL FREQ= 25 YR(DURATION=1) 1=A'(Tc/60).P (CIlY OF BOZEMAN)
BASIN AREA PRE= 0.95 AC STORM EVENT STORM i COEFF INTENSITY
YR B IN/HR
PRE-DEV Tc= 28.3 MIN 2 0.36 0.6 0.57
5 0.52 0.64 0.84
PRE-DEV C= 0.20 10 0.64 0.66 1.05
2.5 0.78 0.64 1.26
STORM A= 0.78 50 092 0.66 1.51
B= 0.64 100 1..01 0.67 1.67
STORM INTENSITY= 1.26 IN/HR
PRE-DEV Qp= 0.24 CFS
POST-DEVELOPMENT
BASIN AREA POST= 0.95 AC
POST-DEVTc= 1S.0 MIN
POST-DEV C= 0.64
STORM INTENSITY= 1.89 IN/HR
POST-DEV Qp= 1.15 CFS
H:\1134\004\DOCS\Design\Stonn\Basin B2 Pond-25yr.xls 1 OF 1 PRINTED: 11/22/2017
GEI#: 1.134.004
DATE: 10/4/2017
ENGINEER: CMW
Basin B2 - 100 yr
MODIFIED RATIONAL METHOD
Qp=CIA
PRE-DEVELOPMENT
RAINFALL FREQ= 100 YR(DURATION=1) i=A*(Tc/60) (CITY OF BOZEMAN)
BASIN AREA PRE..= 0.95 AC STORM EVENT STORM i COEFF INTENSITY
YR A B N HR
PRE-DEV Tc= 28.3 MIN 2 0,36 0.6 0,57
5 0.52. 0.64 0.84
PRE-DEV C= 0.20 10 0.64 0,66 1.05
2.5 0.78 0.64 1.26
STORM A= 1.01 50 0,92 0.66 1.51
B= 0.67 1.00 1.01 0.67 1.67
STORM IN TENSITY,- 1.67 IN/HR
PRE-DEV Qp= 0.32 CFS
POST-DEVELOPMENT
BASIN AREA POST= 0,95 AC
POST-DEV Tc= 15.0 MIN
POST-DEV C= 0,64
STORM INTENSITY= 2.56 IN/HR
POST-DEV Qp= 1.S5 CFS
H:\1134\004\DOGS\Design\Stone\Basin B2 Pond-100yr.xls 1 OF 1 PRINTED: 1 1122/2 01 7
GEI#: 1134.004
DATE: 5/28/2017
ENGINEER: cmw
Basin C - 10 yr
MODIFIED RATIONAL METHOD
Qp=CiA
PRE-DEVELOPMENT
RAINFALL FREQ= 10 YR(DURATION 1) i=A*(Tc/60) " (CITY OF BOZEMAN)
BASIN AREA PRE= 3.7 AC STORM EVENT STORM i COEFF INTENSITY
YR A 8 _ IN HR
PRE-DEV Tc= 28.3 MIN 2 0.36 0.6 0.57
S 0,52 0.64 0.84
PRE-DEV C= 0,20 10 0.64 0.66 1,05
25 0.78 0.64 1.26
STORM A= 0.64 50 0.92 0.66 1.51
B= 0,66 100 1.01 0.67 1.67
STORM INTENSITY= 1..05 IN/HR
PRE-DEV Qp= 0.78 CFS
POST-DEVELOPMENT POND VOLUME: sT13kSE
(CF),
BASIN AREA POST= 3,70 AC „ "3177i9
POST-DEVTc= 15.0 MIN TAIANGLF0ELEASE
DETENTION
POST-DEV C= 0.74837.10 ,.
STORM INTENSITY= 1.60 IN/HR AVERAGE.Vi"i4.UMF
POST-DEV Qp= 4.37 CFS
OUTLET STRUCTURE DESIGN FtEtENTIC9N
(CF)
POND: Basin C-10 yr li082,5 _
H:\1134\004\DOCS\Design\Stcrm\BasinC-10yrxls 1 OF 2 PRINTED: 11/22/2017
Basin C - 10 yr
POND VOLUME CALC'S OUTLET STRUCUTRE CALC'S
Triangle Release Constant Release SLOPE OF ENERGY ORIFICE
DURATION INTENSITY Qp POND VOLUME POND VOLUME PIPE FLOW OUT
(MIN) (IN/H11) (CI-S) (CF) (CP) (FT/FT) (CFS) (CPS)
14.25 1,65 4.53 3186.95 2624.80 0,000 UNUMI 3.353
15.25 .1.58 4.33 325188 2673.90 0.001 ##NUMI
16.25 1.52 4.15 3316,99 2719.06 0.002 0.544
17.25 1.46 3.99 3376.65 2760.67 0.003 2.035
18,25 1A0 3.84 3433.19 2799.05 0.004 2.826
1.9.25 136 3.71 3486.90 2834.50 0.005 3.440
20.25 1.31 3.59 3538.01 2867.27 0.006 3.960
21.25 1.27 3.48 3586.73 2897.56 0.007 4.419
22,25 1,23 3.37 3633.24 2925.57 0.008 4.814
23.25 120 3.28 3677.72 2951.46 0.009 5.2.17
24.25 1.16 3.19 3720.29 2975.39 0.010 5._i73
25.25 1.13 3.10 3761.09 2997.118 0.01.1 5.908
26.25 1.10 3.02 3800.24 3017.85 0.012 6.225
27.25 1.08 2.95 3837.84 3036.61 0.013 6.527
28,25 1.05 2.88 3873.98 30S3.86 0,014 6.81`i
29.25 1.03 2.82 3908.74 3069.68 0.015 7.092
30.25 1.01 2.75 3942,21 3084.16 0.W6 7,358
31.25 0.98 2.70 3974.45 3097.36 0.017 7.615
32.25 0.96 2.64 400.5.54 3109.35 0.01.8 7,863
33.25 0.94 2.59 4035.51 3120.20 0.019 8.104
34.25 0.93 2.54 4064.44 3129.9.5 0.020 8.338
35.25 0.91 2.49 4092.38 3138.67 0.021 8.566
36.25 0,89 2.44 4119.36 3146.39 0.022 8.737
37.25 0,88 2.40 4145A3 3153.17 0.023 9.003
38.25 0.86 2.36 4170.64 3.159.05 0.024 9.21.4
39.25 0.85 2.32 419.5.01 3164.06 0,025 9.421
40,25 0.83 2.28 4218.59 3168.24 0.026 9.623
41.25 0.82 2.24 4241.41 3171.62 0.027 9.821
42.25 0.81 2.21 4263.49 3174.24 0.028 10.014
43,25 0.79 2.17 4284.87 3176,12 0.029 10.205
44.25 0.78 2.14 4305.58 3177.30 0.030 10.391
45.25 0.77 2.11 4325,63 3.177.79 0.03:1 10.575
46.25 0.76 2.08 4345.05 3177.63 0.032 10.755
47.25 0.75 2.OS 4363.87 31.76.84 0.033 10.932
48,25 0.74 2.02 438210 3175,43 0.034 11.107
49.25 0,73 2.00 4399,77 3173.44 0.035 11.279
50,25 0.72 1.97 4416.89 3170,87 0.036 11.448
51.25 0.71 194 4433.48 3167.75 0.037 11.615
52,25 0.70 1.92 4449 S7 3164.09 0.038 11.779
53.25 0.69 1.90 4465.1E 3159.92 0.039 1.1.941
54.25 0.68 1.87 4480.26 3155.24 0.040 12.101
HA1134\004\DOCS\Design\Storm\Basin C-10yr.x1s 2 OF 2 PRINTED: 11/22/2017
GEIN: 1,134.002
DATE: 5/28/20.17
ENGINEER: CMVJ
Basin C - 25 yr
MODIFIED RATIONAL METHOD
Qp=CiA
PRE-DEVELOPMENT
RAINFALL FREQ= 25 YR(DURATION= 1) 1=A*(Tc/60) " (CITY OF BOZEMAN)
BASIN AREA PRE= 3.7 AC STORM EVENT STORM i COEFF INTENSITY
YR A B (IN/HR
PRE-DEVTc= 28.3 MIN 2 0.36 0.6 0,57
5 0.52 0.64 0.84
PRE-DEV C= 0.20 10 0,64 0.66 1.05
25 0.78 0.64 1..26
STORM A= 0.78 50 092 0,66 1.51
B= 0,64 100 1.01, 0.67 1.67
STORM INTENSITY= 1.26 IN/HR
PRE-DEV Qp= 0.93 CFS
POST-DEVELOPMENT
BASIN AREA POST= 3.70 AC
POST-DEVTc= 15.0 MIN
POST-DEV C= 0.74
STORM INTENSITY= 1.89 IN/HR
POST-DEV Qp= 5.19 CFS
H:\1134\004\DOCS\Design\Storm\Basin C-25yr.xls 1 OF 1 PRINTED 11/22/2017
GEI#: 1134.002
DATE: 5/28/20.17
ENGINEER: CMW
Basin C - 100 yr
MODIFIED RATIONAL METHOD
Qp=CiA
PRE-DEVELOPMENT
RAINFALL FREQ= 100 YR(DURATION=1) i=A"(Tc/60) " (CIl'Y OF BOZEMAN)
BASIN AREA PRE= 3.7 AC STORM EVENT STORM i COEFF INTENSITY
YR A B IN/HR
PRE-DEV Fc= 2.8.3 MIN 2 0.36 0.6 0.57
5 0.52 0.64 0.84
PRE-DEV C= 0,20 10 0.64 0.66 1.05
25 0.78 0.64 1.26
STORM A= 1.01 50 0.92 0.66 J.51
B= 0.67 1.00 1.01 0.67 1.67
STORM INTENSITY= L67 IN/HR
PRE-DEV Qp= 1.24 CFS
POST-DEVELOPMENT
BASIN AREA POST= 3.70 AC
POST-DEV Tc= 15.0 MIN
POST-DEV C= 0.74
STORMINTE.NSITY= 2.50 IN/HR
POST-DEV Qp= 7.00 CFS
H'\1134\004\DOCS\Design\Storm\Basin C-100yr.xls 1 OF 1 PRINTED: 11/22/2017
1 2" Curb Chase
Project Description
Friction Method Manning Formula
Solve For Discharge
Input Data
Roughness Coefficient 0.013
Channel Slope 0.01000 ft/ft
Normal Depth 0,38 ft
Bottom Width 1.00 ft
Results
Discharge 1,56 ft'/s
Flow Area 0.38 ft-
Wetted Perimeter 1.76 ft
Hydraulic Radius 0.22 ft
Top Width 1.00 ft
Critical Depth 0,42 ft
Critical Slope 0.00743 ft/ft
Velocity 4.11 ft/s
Velocity Head 0,26 ft
Specific Energy 0,64 ft
Froude Number 1.18
Flow Type Supercritical
GVF input Data
Downstream Depth 0.00 ft
Length 0,00 ft
Number Of Steps 0
GVF Output'Data
Upstream Depth 0,00 ft
Profile Description
Profile Headloss 0.00 ft
Downstream Velocity Infinity ft/s
Upstream Velocity Infinity ft/s
Normal Depth 0,38 it
Critical Depth 0.42 ft
Channel Slope 0.01000 ft/ft
Critical Slope 0.00743 ftlft
Page 1 of 1
10/4/2017 9:38:17 AM
N p�-
3� fD O
L � N
N > N
C q d
0)Q
c ()
w E
u
in
a
C
Q
i
O
0 0 0000
tnOtn0000
®C37 rr-O® O
�.- . . O O O O 0-)Oyu GU (() N
-- c- +
N co
Cam......_ .._.._.... _...__.. . N
J 0.°(/? ( Oco
Q
v
II O
i � I + �
O
` fill I I,I N
1
I_ 1. N O O
6 c6
t ij j! O 0) 0)O U
0
Y
I •�
I O
( ^` LO
1 �... I �+�• W m
O00
.
�,1 r -0� C
QC N O (� N
ly i, O m
+ m
j O
1 1 0
Io
1 ,
_I!I iI
_�
=61-- ® t II T
O
0 C C
Oo m5
a� 0 ® a�' a
O E � �
/N !_..... 1. ._.� O n o
.JLLV1 co
4z2
(D
\\
\ \
\�
2
\
co
C \
CL
2 �) � [
a a = a22a LU _
° c 3 G 7
I- L62 ¥co
w
2 8 EG {
° \ § :3
CL
\¥ '0
g 0
�
2 7 / )
\CD
O 2
_ = li
/ { ) \ E \ \
£ 7 0
\ ¥ § a) e / % 0
CL
\ E a
UT-w2) G 2
\ \ \ / )
) G 8 $ % 7
@ ^ @ / 8 / 7 E
w \ / ) a a a x )
� g / $
° 7 \ In
$ \ \ �
/¥ 2 / 2
g & E [
\ 2 )
° \ ` * {
o ) 0 a /
) y y o =
RI f E \ & E ) \I
\\\ \ \ / ® ok u2zi � � 0
a \� j ° m / f ~ a 0 G E ) »
) ; / t \ \ \ J ® \ E / / ( o e / \
° 2 ® \ ® % E $ \ § c o a 3 , G
\ \ - t { \ ® \ \ 2 {
22/ � & \ m ) iE m ( \ \
\t2 ( E6 / jj / \ \ \ j � ° os ƒ/ / .
m m m z 2 2 2 2 3 �7
} -C }
0E— W pC)
zWQ W1z I
OfJ_ D MID
CL ® i l
p z � i
U)
zz I
U) O
X
CL
W
—�
�i � �—
l ' CL
0
C/)
-s No-
r
U)
zr%loo Q i
C� j I_r 1
1--- w
i
i
i
_ _ _.
J.C. Billion Auto Plaza
Property Owners' Association
Appendix A
Storm Water Facilities Operation & Maintenance Manual
Overview
The HOA is responsible for maintaining all Storm Water Facilities,including storm inlets,sidewalk chases,curb cuts,
outlet structures,storm pipe and the storm water detention ponds located within the open space areas of the
subdivision. The HOA is also responsible for maintaining the storm pond and outlet structure serving Competition Drive
that is located on Lot 1A, Block 3. The individual lot owners are responsible for maintaining all of the Storm Water
Facilities including storm inlets,sidewalk chases,curb cuts,outlet structures,storm pipe and the storm water detention
ponds located on their respective lots unless otherwise directed above.
Maintenance
The storm inlets and pond outlet structures are to have the sediment removed from the sediment traps on a yearly
basis or an updated maintenance schedule as determined by monitoring the sediment build-up of the inlets quarterly.
The storm pipe between the storm inlets is to be monitored yearly for build-up of sediment or trash. If the storm
system is operating correctly the build-up should be minimal and therefore maintenance schedule will be directly
correlated to the yearly inspection findings.
The storm water detention ponds shall be monitored every five years for sediment build-up. When the sediment build-
up starts to decrease the capacity of the detention pond the sediment shall be removed mechanically and hauled from
the site. It the extraction of the sediment removes the vegetation from the bottom of the pond, it should be reseeded
or re-sodded and appropriate storm water BMPs are to be installed until the vegetation is stabilized.
Curb cuts and sidewalk chases should be monitored every 6 months for sediment build-up or blockage. A common
issue with these storm facilities is the build-up of grass at the daylight that impedes flow and collects sediment.These
facilities should be cleaned yearly or more frequently if deemed necessary during the inspections. The sediment,trash
and vegetation should be hauled offsite.
Contact Information
Property Manager:
Association President: