HomeMy WebLinkAboutDrainage Reports - 10/12/1995 (2)Report
Final Storm Drainage Report eS� a¢�&LLI
for
J.L. WEST MINOR SUBDIVISION
A TRACT OF LAND IN THE NW 1/4, SECTION 18-7-69
August 1995
' Stewart & Associates
Consulting Engineers and Surveyors
103 South Meldrum Street
Fort Collins, Colorado 80521
' (970) 482-9331
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FINAL STORM DRAINAGE REPORT
FOR
NW 1/4 SECTION 18-7-68
Southeast corner of Lemay and Riverside
GENERAL SITE
The project proposed for this 0.91 acre site is a drive -through restaurant. This parcel
is zoned C, commercial, and the restaurant use proposed is consistent with current land use
planning. Land use is considered a "use -by -right," by the City of Fort Collins Planning
Department. The project area falls in the Southeasterly most edge of the Old Town Basins.
Historical use of the site was indoor storage for B&M Roofing in a metal building, which
included a gravel parldng lot. In approximately 1991 the steel building was dismantled and only
a gravel parldng lot along with some concrete pads remain.
Adjacent land uses include the Fort Collins Firestone Tire Store on the South off Lemay
Avenue (Lemay) and Autobahn West car repair shop on the East addressed off Riverside Avenue
(Riverside). Both existing businesses have been graded and built so that no runoff from offsite
will be directed onto this project. Following the dismantling of the B&M Roofing facilities the
site was left with a rough irregular surface that has become overgrown with dryland grasses and
weeds.
HYDROLOGY
Historic hydrologic conditions on the site have been established using the roofing
company as existing. Years before the street improvements were made at the Riverside and N.
Lemay intersection, the building and outdoor storage existed. Using information from
topography collected in 1980, the building was 6734-sq. ft. and the gravel covered the entire
site. This led to a historic runoff coefficient of 0.58 and a time of concentration (TOC) for
historic conditions of 18.1 minutes. Using "heavy soils" with slopes of less than 2 percent, the
Rational Method yielded 2-year direct runoff of ± 1.0 cubic feet per second (cfs). This runoff
was released as sheet flow into the flowlines of Riverside and Lemay. Detention will now be
provided for this site allowing nothing greater than the 2-year historic mentioned.
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Final Storm Drainage Report
J.L. West
Following construction of the current proposal and the anticipated development, the
Rational Method showed flows of 2.4 cfs and 4.9 cfs for the 10 and 100 year events
respectively. Important to note is that these runoff rates are based on the additional parldng and
a second small structure suggested on the architectural plan. Detention will be provided with
releases directed into the existing storm drainage collection system along Lemay. The connection
will be made approximately 100-feet South of the Lemay & Riverside intersection, on the East
side of Lemay, into an existing 2-foot combination inlet. There is a 12-inch outlet pipe exiting
the Lemay inlet that releases into the Poudre River. The river is ± 500-ft north of the project
area and crosses Lemay. This inlet will be the point of release for the newly constructed
detention pond on this project. A new 15-inch RCP pipe will be connected to this inlet that will
be installed as the outlet to the detention pond.
A deceleration lane has been required for this project. The grading on Riverside will
require an offsite inlet be constructed for this street improvement. In the 10-year event the 0.15
acre 1/2 street basin develops 0.81 cfs and 1.12 cfs in the 100-year event. A 12 inch PVC pipe
and manhole will be constructed to release into that same existing storm drain system. The
following table is a summary of the site hydrology:
HYDROLOGY SUMMARY TABLE J.L. WEST
BASIN
C
Q10 ON
TOC(min)
Qlpp(efs)
TOC(min)
COMMENTS
HISTORIC
0.58
* 1.0
18.1
N/A
N/A
* 2-YR (Q)
DEV."A"
0.25
0.06
9.2
0.13
8.7
UNDETAMD
DEV. "B"
0.76
2.43
8.0 1
4.89
6.1
DETAINED
ST-1
0.15
0.81
1.9
1.12
1.9
UNDETAINED
ivvIZ: ruLure uevempment nas oeen tncivaea ror oetenuon sizing, ana the release rate nas oeen
adjusted down for the 100-yr undetained.
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Final Storm Drainage Report
J.L. West
HYDRAULICS
No specific hydraulic design will be a part of this report. The only hydraulic element that
will be considered is the orifice sizing on the outlet from the new pond. The orifice size will be
2.38-in radius for a round opening with the available driving head at the pond HWL of 4956.95-
ft. The associated 12-inch piping provides flow velocities greater than 2 feet per second, and
provides flow capacity of approximately twice the 0.90 cfs flowing from the pond. Because of
the historic condition of the site and the inability to identify specifics associated with the piping
to the Poudre River the approach taken is within the criteria of the SDDCCM.
Noteworthy is that the City of Fort Collins Engineering Department required that a
deceleration lane be constructed on Riverside which would include a new curb inlet. Grading
along Riverside has made the new 4-foot curb inlet necessary since a pan following along the
existing curb alignment and grade was deemed unacceptable. It was also concluded that
connecting the inlet to the existing storm drain on the east side of Lemay was the best solution.
The 12-inch existing concrete pipe at 0.6 percent parallel to Lemay has adequate capacity for
these minor flows being directed toward it.
DETENTION
A detention pond is being included in the design of the J.L. West property. The pond is
being sized to account for future development which has been conceptually shown by the
architect. Using the FAA method to establish the pond size, and the 2-yr historic rate minus the
100-yr undetained runoff led to a volume of 3,702 cu.ft. being required. Under future condition
the runoff coefficient increased from the current developed value. This increase went from a
weighted value of 0.61 to a future value of 0.64. Weighting of these values is following the
methods outlined in the SDDCCM.
Inlet control is being used to regulate the outlet flow rate. The 0.9 cfs was the result of
the calculation 1.03 cfs(2-yr site historic) minus the undetained (100-yr) 0.13 cfs equaling the
0.9 cfs rate. The pond release will be directed into the existing curb inlet as mentioned, with a
12-in ADS pipe conveying the flow. The existing pipe network flowing Northerly is shown on
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Final Storm Drainage Report
J.L. West
the grading plan.
The North Lemay Avenue driveway will function as the emergency spillway should the
inlet to the piping system become clogged. Depth in the detention pond will increase by 0.20
feet prior to going out of the driveway and into Lemay. This minor increase in pond depth in
the unlikely scenario of clogging does not present a concern for this project or adjacent property
owners.
CONCLUSIONS
This use -by -right project does not present any concerns to the adjacent land owners or
land use. Detention is being provided onsite with the undetained areas being subtracted at the
100-yr rate from the 2-yr allowable historic release rate. This methodology will provide a level
of confidence that the existing pipe network will not be overwhelmed in either the 2-yr or 100-yr
events.
A variance is being requested for the half street flows in both Lemay and Riverside
adjacent to the property. Street improvements to the intersection of these arteriakhave improved
street grading but have limited this sites ability to gather and retain those street flows. In
providing onsite detention for our project, grading does not allow for a gravity collection of
these street runoffs. Consequently by minimizing the undetained offsite flow, and providing
onsite detention, no impact to the existing conditions will result. Should questions arise during
your review for approval of this storm drainage design please feel free to contact Alex Evonitz
or myself so we may help in your understanding.
Respectfully,
Richard A. Rutherford, P.E. & L.S. # 5028 *j028
a
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' EROSION CONTROL REPORT
The 0.91 acre site is in a moderate wind and moderate rainfall
' erodibility area. The site is surrounded by existing developed
property that will need to be protected during construction
activity. This protection will take the form of structural method
' identified in the SDDCCM.
Highest exposure to erosion during the construction will be at
' the point of rough grading for the parking area. Before any
construction begins, a silt fence will be installed around the
perimeter of the project with a gravel inlet -filter placed at the
' Lemay Street curb inlet. These factors alone will suffice in
providing the performance standard, 71.0 percent, calculated for
' the site. The effectiveness of these measures will be 94.8 percent,
' well above what is required. With the accelerated construction
generally incorporated for this type of project no concern has
tarisen because of erosion concerns. Please reference the erosion,
calculations included as part of this total report submission
' package.
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' EROSION CONTROL CALCULATION FOR
J.L. WEST
' PROPERTY NW 1 /4
' S.E. CORNER LEMAY & RIVERSIDE
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STEWART&ASSOCIATES 103 PH. S. 9 3DIRUM, FAX FORT gOLLINS, CO 80521
Consulting Engineers and Surveyors
1 By: trk� Date: 4 -Z 8 -5 S Client: S -1, .(Je;,— Sheet No. of r
tProject: J.L. �e�tAz�il�4�� S .�. Can e= cam (at,a
Subject: ^Ti ni,a.
Esc
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�C L_P7. _ i 750'
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CONSTRUCTION SEQUENCE
PROJECT:.
STANDARD FORM C
QUENCE. FOR 19 S ONLY COMPLETED BY: —pq,
DATE: ZS_
dicate by use of a bar line or symbols when erosion control measures will be installed.
jor modifications to an approved schedule
may require submitting a
proval by the City Engineer.
new schedule for
YEAR
------MONTH-
-- --
--I-- ---
�ERLOT GRADING
---i
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---�----
---i
---- -----
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----I----I----�
WIND EROSION CONTROL
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Soil Roughing
�
Perimeter Barrier
Additional Barriers
Methods
'Vegetative
Soil Sealant
j
Other
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INFALL EROSION CONTROL
'STRUCTURAL:
Sediment Trap/Basin
Inlet Filters
Straw Barriers
Silt Fence Barriers
Sand Bags
Bare Soil Preparation
Contour Furrows
Terracing
Asphalt/Concrete Paving
Other
tVEGETATIVE:
Permanent Seed Planting
Mulching/Sealant
'Temporary Seed Planting
'Sod Installation
Nettings/Mats/Blankets
Other i
-------------------------------------------------------------L1----------LL----
SJUCTURES: INSTALLED BY %,C . MAINTAINED BY
VEGETATION/MULCHI'NIG CONTRACTOR
`C{�
OP,E SUBMITTED — 1 s APPROVED BY CITY OF FORT COLLINS ON
H[tSF-C:1989
Rainfall Performance Standard Evaluation
J.1_. wa-r
Project: S �. C'cR„ L�ti���, Standard Form A
By: Stewart & Associates Completed: N—(L
103 S. Meldrum
Fort Collins, Colorado 80521 Date: i 1
Developed
Subbasin
Erodibility
. Zone
Asb
acres
Ub
feet
Ssb
%
Lb
feet
Sb
%
PS
%
ho
01.5
-71 `V
HDI/SF—A:1989
PAGE 23
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STEWART&kSSOCIATES 103 S. ME DR31 FMCFO �TCOLLINS, CO80521
Consulting Engineers and Surveyors
382
By: AI,, Date: l\ - 3 - I Client: 7 A Je::r Sheet No. __L_ of
Project: �A Wei.; S.&. Coca 2 oa (e"e�, i ZIUC2,z,ue�
Subject: L_?Ix
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Effectiveness Calculation
T.L. We�TS COQN�R�
Project: LT-, 4 i, , K. kas Standard Form B
By: Stewart & Associates Completed: ' A(/,AL
103 S. Meldrum
Fort Collins, Colorado 80521 Date: 11 / 3 /
Erosion iAJiC—
MethodValuc
Factor
Y —Factor
Value
Comments:
BA-(Z; SalL1.vo
0.10
�ax,h z2�C�cP2
'JILT F�-i:
1.00
0.15
C�2Au21,
o. U6
1,'DO
�r �yE�aNe C�,z.nss
o
no
1�tazKi 1oc C„zr,, . ,ii a
i= 3o ropS�—NOsvno- IOoo S�.
I,D% Zt0.
✓0�A1
' HDI/SF—B:1989
I
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Table 5.2 C-Factors and P-Factors for Evaluating EFF Values.
Treatment C-Factor P-Factor
BARE SOIL
Packed and smooth . . . . . . . . . . . . 1.00
Freshly disked. . . . . . . . . . . . 1.00
Rough irregular surface . . . . . . . . . 1.00
SEDIMENT BASIN/TRAP. . . . . . . . . . . . . . 1.00
STRAW BALE BARRIER, GRAVEL FILTER, SAND BAG. 1.00
SILT FENCE BARRIER . . . . . . . . . . . . . . 1.00
ASPHALT/CONCRETE PAVEMENT. .. 0j1
ESTABLISHED DRY LAND (NATIVE) GRASS. . . See Figure
SOD GRASS. . . . .. . . . . . . . . . . . 0.01
TEMPORARY VEGETATION/COVER CROPS . . . . . . . 0.45(2)
HYDRAULIC MULCH @ 2 TONS/ACRE. . . . . . . . . 0.10(3)
SOIL SEALANT . . . . . . . . . . . . . . . 0.01-0.60(4)
EROSION CONTROL MATS/BLANKETS. . . . . . . . . 0.10
HAY OR STRAW DRY _MULCH 103-
After planting grass seed, apply mulch at
a rate ot Z tons acre (minimum) and adequately
anchor, tack or crimp material into the soil.
Maximum
1.00
0.90
0.90
0.50(1)
0.80
0.50
1.00
1.00
1.00
1.00
1.00
1.00
1.00
A-0
Slope
Length
_
W
(feet)
1
to
5
400 . . . . .
. . ... 0.06
1,00
6
to
10
200 . . . . .
. . . . 0.06
1.•00
'
11
to
15
150 . .
0.07
1.00
16
to
20
100 . . . . .
. . . . 0.11
1.00
21
25
to
to
25
33
75 . . . . .
50
. . . . 0.14
0.17
1.00
1.00
>
33
35
0.20
1.00
NOTE:
Use
of other
C-Factor or P-Factor values reported
in this
table
must be
substantiated by
documentation.
(1) Must be constructed as the first step in overlot grading.
(2) Assumes planting by dates identified in Table 7.4 thus dry
or hydraulic mulches are not.required.
(3) Hydraulic mulches shall be used only between March 15 and
May 15 unless irrigated.
(4) Value used must be substantiated by documentation.
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a
0.35
1t
0 0.25
U
0.20
b 0.15
0.10
0.05
PAGE 26
FORT COMS, COLORADO
1
102030405060 7080 90 100
ESTABLISHED (MASS GROUND- COVER (7)
FIGURE 5.1
7
1
BASIN CONSTITUENTS FOR
J.L. WEST
PROPERTY NW 1/49
' S.E. CORNER LEMAY & RIVERSIDE
1
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Hi
N
N
N
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SITE HYDROLOGY FOR
J.L. WEST
PROPERTY NW 1/49
S.E. CORNER LEMAY & RIVERSIDE
r r r rr r r r r r r �r r r r rr r r �r r
Standard Form SF-9
J.L. West, Tract in the NW 1/4 Section, 18-7-68
Calc•ed.By: AVE Storm Drainage System Design Job No. 542
Date: 8-95
Checked By: FDB (Rational Method Procedure)
Project J.L West
Design Storm: 2/ 10 / 100 Year
J.L West Is On the SDWhe Ae} t.n.r.nr m I
Area
Design
Toui.itc
u .dchivcd
TotJ.lu
u.Mni.ee
T.ai.i a
TOW .ik
roni. a
iv/�jik\v<:::vvC:::
t2
t2.ae.t
Area
acres
0.91
,f.
0 07
O 84
0.07
0.84
:k;<v
0.91
0.91
•
vui i.}L:I�.iSrv}'C:'�OtiCii'4:.i4
:._: _
0 .15
0.15
DIffEGT
Runoff
Coefficient
0.58
: '
0 20
0 61
0.25
0.76
•.: `;r,:<s:
0.64
0.80
0.95
1.00
RUNOf..F:
C X A
0.529
'Y' >3
0,014
0.512
0018
0.638
0.583
0.728
... �i::::J$iii
0.143
0.150
Time (c)
min
18.1
<. `:. .xo%
9.2
8.0
8.7
6.1
h^'•,;>..:.a
7.6
5.6
::}C�iC{: �Cfi:�:`;
1.9
1.9
Intesity
in/h
1.95
}; ; <;;}
4.55
4.75
7.23
7.66
4.84
7.41
AC...�C:Ve. .:f:.
5.7
7.47
Runoff
cfs
1.03
:.; . � .03
..
0.06
2.43
0.13-N/A��
4.89
;},s >:;t.,:>`:,,
2.82
5.39
:C:.�:;}.i:::'.}'i
0.811
1.12
TOTAL RUNOFF
Time (c) Intesity SUM of
min in/hr C X A
N/A N/A
:; I
'•'�''
N A N/A
8.0 4 75 0 512
6.1 7.66 0.638
7.6 4.84 0.583
5.6 7.41 0.728
}•: Cv�
N /A /A N/
N/A N/A N/A
Runoff
cfs
N/A
;' .;
..
2.4
4.9
2.8
5.4
N/
N/A
TREETS
Street
Sloe %
N/A
'o,.;s.G`. a.�:.,:"c`f.:.
/A
N A
/A
N A
N/A
N/A
:'
Street
Flow cfs
N/A
N A
N A
q
N A
Design
Flow cfs
PIPE
Slope
%
Pipe Size
in
µ+tauwia
Travel::Time
a muo
arnnana, cnannw
Remarks
Street
Pro rt historic
F.•�
"F'^ •'
Dewlo d A 10- r
Demob a s 10
Design
Point
L.m.ycao
}`
:}r:,>.,,, ea
L.m. cao
y
Dete.tro.
t<m.ycao
D<a..io.
Length
Velocity
f s
Time (t)
(min)
N/A
/A
N/A
':?w`<fo:°",.:
/A
N/A
:,'t�:y :<:':�;;at» f
N A
N/A
::;:?;:>:«..�o
y.}: .. :.
N /A
.'<•ax: .;s:�::.y:
} •.�.P..F T
N/A
,.;. Cp':.:o
C.: ... }
His. Runoff for Aflowable Release
o.; .::.`:.:..Y may+C:v..
t .}..:....Y :hx:F:R.,
N A
, /A
N/A
10- ear ev o Hoff
N/A
-����
A
/A
N/A
N/A
N/A
I N/A
N/A
N A
N/A
N/A
I 10- ear Develo ed Runoff
Develo d A 100-
Develo d B 100- r
N A
A
N A
N A
-yearDevelo a Runoff':
q;;•<;;: ti:
Pro [uturel0
Pro rt future 300
♦:. •••v
Lema Street 10
Loma Street 100- r
t..^M,.'�..`:?..>.:x:H
co.ei..a
c.uni..a
nCivtC
:
N t i .
Ne+Icier
q
NA
/A
N
10- ear afore noff
-ear Future Runoff
.......
..
.:.. .:.:..:
.. }.:::.....:.�.:.
/A
A
F::..�.wx: �i�:: <.:o• �f.
10- ear Deve o ed ono
/A
N/A
/
A
/A
N/A
N/A
N/A
N/A
N/A
N A
N/A
100- Bar DeVelO ed RUrtoff
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STEWAru&AssocIATES
Consulting Engineers and Surveyors
103 S. MELDRUM, FORT COLLINS, CO 80521
PH. 482-9331 FAX 482-9382
By: Date: Client: Sheet No. —of
Project: -c2
Subject:
x�
r
T-J
--7
7-1
7
z - j
�7-77
4
----------------------------------- ------------ -------------------------
' REPORT OF STORM SEWER SYSTEM DESIGN
USING UDSEWER-MODEL 10-19-1992
DEVELOPED
BY
' JAMES C.Y. GUO ,PHD, PE
DEPARTMENT OF CIVIL ENGINEERING, UNIVERSITY OF COLORADO AT DENVER
IN COOPERATION WITH
' URBAN DRAINAGE AND FLOOD CONTROL DISTRICT
DENVER, COLORADO
-------------------------------------
*** EXECUTED BY STEWART AND ASSOCIATES (FT
rOLLINS-COLORADO)............................
ON DATA 05-26-1995 AT TIME 09:26:40
'*** PROJECT TITLE :
** RETURN PERIOD OF FLOOD IS 5 YEARS
' RAINFALL INTENSITY FORMULA IS GIVEN
** SUMMARY OF HYDRAULICS AT MANHOLES
t------------------------------------------------------------------------------
MANHOLE
CNTRBTING
RAINFALL
RAINFALL
DESIGN
GROUND
WATER
COMMENTS
ID NUMBER
AREA * C
DURATION
INTENSITY
PEAK FLOW
ELEVATION
ELEVATION
---------------
MINUTES
INCH/HR
CFS
FEET
FEET
10.00
------
0.00
------------------------------------------------------
0.00
0.00
0.90
55.62
55.12
OK
11.00
0.00
0.00
0.00
0.90
59.50
55.35
OK
12.00
0.00
0.00
0.00
0.90
56.40
55.51
OK
13.00
0.10
0.00
0.00
0.90
56.40
56.41
NO
FK MEANS WATER ELEVATION IS LOWER THAN GROUND ELEVATION
1** SUMMARY OF SEWER HYDRAULICS
----- NOTE: THE GIVEN FLOW DEPTH -TO -SEWER SIZE RATIO= .9
-------------------------------------------------------------------
SEWER MAMHOLE NUMBER SEWER REQUIRED SUGGESTED EXISTING
' ID NUMBER UPSTREAM DNSTREAM SHAPE DIA(HIGH) DIA(HIGH) DIA(HIGH) WIDTH
ID NO. ID NO. (IN) (FT) (IN) (FT) (IN) (FT) (FT)
' 110.00 11.00 10.00 ROUND 8.98 12.00 0.00 0.00
120.00 12.00 11.00 ROUND 8.63 12.00 0.00 0.00
130.00 13.00 12.00 ROUND 7.16 12.00 0.00 0.00
tIMENSION UNITS FOR ROUND AND ARCH SEWER ARE IN INCHES
DIMENSION UNITS FOR BOX SEWER ARE IN FEET
FEQUIRED DIAMETER WAS DETERMINED BY SEWER HYDRAULIC CAPACITY.
UGGESTED DIAMETER WAS DETERMINED BY COMMERCIALLY AVAILABLE SIZE.
FOR A NEW SEWER, FLOW WAS ANALYZED BY THE SUGGESTED SEWER SIZE; OTHERWISE,
fXISITNG SIZE WAS USED
------------------------------------------------------------------------
SEWER DESIGN FLOW NORMAL NORAML CRITIC CRITIC FULL FROUDE
OMMENT
ID
FLOW Q
FULL Q
DEPTH
VLCITY
DEPTH
VLCITY
VLCITY
NO.
NUMBER
------------------------------------------------------------------------------
CFS
CFS
FEET
FPS
FEET
FPS
FPS
110.0
0.9
2.0
0.48
2.44
0.41
2.97
1.15
0.71 V-OK
120.0
0.9
2.2
0.45
2.64
0.41
2.97
1.15
0.79 V-OK
130.0
0.9
3.6
0.34
3.79
0.41
2.97
1.15
1.33 V-OK
iROUDE NUMBER=O INDICATES THAT A PRESSURED FLOW OCCURS
SEWER
SLOPE
INVERT ELEVATION
BURIED
DEPTH COMMENTS
ID
NUMBER
UPSTREAM
DNSTREAM
UPSTREAM
DNSTREAM
$
(FT)
(FT)
(FT)
(FT)
110.00
0.30
--------------
54.85
-----------
54.59
----------
3.65
---------- ----
0.03 NO
120.00
0.37
55.05
54.88
0.35
3.62 OK
130.00
1.00
55.06
55.05
0.34
0.35 OK
�K
MEANS BURIED
DEPTH
IS GREATER THAN REQUIRED SOIL COVER OF .3 FEET
t** SUMMARY OF HYDRAULIC GRADIENT LINE ALONG SEWERS
SEWER
ID NUMBER
110.00
' 120.00
130.00
------------------
SEWER SURCHARGED
LENGTH LENGTH
FEET FEET
---
88.00 0.00
46.00 0.00
1.00 0.00
CROWN ELEVATION
UPSTREAM
DNSTREAM
FEET
FEET
----
55.85
55.59
56.05
55.88
56.06
56.05
----------------------------
WATER ELEVATION FLOW
UPSTREAM DNSTREAM CONDITION
---FEET FEET
--------------------
55.35 55.12 SUBCR
55.51 55.35 SUBCR
56.41 55.51 JUMP
(RSS'ED=PRESSURED FLOW; JUMP=POSSIBLE HYDRAULIC JUMP; SUBCR=SUBCRITICAL FLOW
�I
1
11
** SUMMARY OF ENERGY GRADIENT LINE ALONG SEWERS
UPST MANHOLE SEWER
SEWER MANHOLE ENERGY FRCTION
ID NO ID NO. ELEV FT FT
110.0 11.00 55.44 0.30
120.0 12.00 55.62 0.17
130.0 13.00 56.64 1.00
----------------------------------------------
JUNCTURE LOSSES
DOWNST
MANHOLE
BEND
BEND
LATERAL
LATERAL
MANHOLE
ENERGY
K COEF
LOSS FT
K COEF
LOSS FT
ID
FT
----------------------------------------------
1.01
0.02
0.00
0.00
10.00
55.12
0.46
0.01
0.00
0.00
11.00
55.44
0.05
0.00
0.25
0.02
12.00
55.62
BEND LOSS =BEND K* VHEAD IN SEWER.
LATERAL LOSS= OUTFLOW VHEAD-JCT LOSS K*INFLOW VHEAD
FRICTION LOSS=O MEANS IT IS NEGLIGIBLE OR POSSIBLE ERROR DUE TO JUMP.
FRICTION LOSS INCLUDES SEWER INVERT DROP AT MANHOLE
NOTICE: VHEAD DENOTES THE VELOCITY HEAD OF FULL FLOW CONDITION.
A MINIMUM JUCTION LOSS OF 0.05 FT WOULD BE INTRODUCED UNLESS LATERAL K=O.
FRICTION LOSS WAS ESTIMATED BY BACKWATER CURVE COMPUTATIONS.
�•_ O.OLO CMP
•' . 55
Solutions by Kutter's Formula" aOl' Put '
✓1 0•/5 Sirel
'
/;7
'I
_ (1 li oO O�ODUOti /R
noa/
9 L?� 39'
I iI �� .0001 t
. 4
244 • .COOS
.0006
L5
.0001
v' h
COZ
�. •� �: j iB, /6"' y? .moo
i 20 a
2
:003
/1
.005
i y moo. /0' d Q°- 00,
+. _ .007
COj
I .0 LO
_ 08 3.n
ri
6.
.. ' '=0.5 .04
�. R4 .06 4.0 ,\ •
.01
.03
.09
/ 4.5 I
s.0 -_l
5.5- I'
11 z .4 6.0
- x
7.0
Tig. ld: Iiutter's formula for circular pipes
Diagram for the solution of
flowing full•
yy i
No Text
1
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DRAINAGE CRITERIA MANUAL
30
F- 20
z
w
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cc
III
0. 10
z
w
a
O 5
w
¢ 3
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U 2
cc
w
H
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RUNOFF
■■011111WA
1311111FA
/�
FA
M
r
�
•
�/��II�I�■■Ili
I������■/�
-_V_M_IAMIAI��_-_�_m_moom■■-_
MWMMFAMAM
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NVANIMM--■■■■■11-
■
. -
MWAN.■■1FAMM
■■■■■■11■�
.2 .3 .5 • 1 1 ;15 2 ' 3 5 10 20
VELOCITY IN FEET PER SECOND
FIGURE 3-2. ESTIMATE OF AVERAGE FLOW VELOCITY FOR
USE WITH THE RATIONAL FORMULA.
*MOST FREQUENTLY OCCURRING"UNDEVELOPED"
LAND SURFACES IN THE DENVER REGION.
REFERENCE: "Urban Hydrology For Small Watersheds" Technical
Release No. 55, USDA, SCS Jan. 1975.
■
5 -1-84
URBAN DRAINAGE & FLOOD CONTROL DISTRICT
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DETENTION SIZING FOR
J.L. WEST
PROPERTY NW 1 /4,
S.E. CORNER LEMAY & RIVERSIDE
------------------------------------------------ ---_ -------
DETENTION POND SIZING BY FAA METHOD
' Developed by
Dr. James Guo, Civil Eng. Dept., U. of Colorado
Supported by Denver Metro Cities/Counties Pool Fund Study
Denver Urban Drainage and Flood Control District, Colorado
l;ER=Stewart and Associates -Ft Collins Colorado ..............................
EXECUTED ON 12-09-1994 AT TIME 14:28:31
'PROJECT TITLE: J.L. West @ Lemay & Riverside
'*** DRAINAGE BASIN DESCRIPTION
BASIN ID NUMBER = 1.00
' BASIN AREA (acre)= 0.84
RUNOFF COEF 0.80
***** DESIGN RAINFALL STATISTICS
DESIGN RETURN PERIOD (YEARS) = 100.00
INTENSITY (IN/HR) -DURATION (MIN) TABLE IS GIVEN
LRATION 5 10 20 30 40 50 60 80 100 120 150 180
INTENSITY 9.0 7.5 5.2 4.2 3.5 3.0 2.6 2.1 1.7 1.5 1.2 1.0
***** POND OUTFLOW CHARACTERISTICS:
MAXIMUM ALLOWABLE RELEASE RATE _ .9 CFS
OUTFLOW ADJUSTMENT FACTOR = .945
AVERAGE RELEASE RATE _ .8505 CFS
' AVERAGE RELEASE RATE = MAXIMUM RELEASE RATE * ADJUSTMENT FACTOR.
[]
1
' ***** COMPUTATION OF POND SIZE
------------------------------------------------
RAINFALL
RAINFALL
INFLOW
OUTFLOW
REQUIRED
DURATION
INTENSITY
VOLUME
VOLUME
STORAGE
MINUTE
INCH/HR
ACRE -FT
ACRE -FT
ACRE -FT
'--
----------------------------------------
0.00
0.00
0.00
0.00
0.00
5.00
9.00
0.04
0.01
0.04
10.00
7.50
0.07
0.01
0.06
'
15.00
6.35
0.09
0.02
0.07
20.00
5.20
0.10
0.02
0.07
'
25.00
30.00
4.70
4.20
0.11
0.12
0.03
0.04
0.08
0.08
35.00
3.85
0.13
0.04
0.08
40.00
3.50
0.13
0.05
0.08
45.00
3.25
0.14
0.05
0.08
50.00
3.00
0.14
0.06
0.08
55.00
2.80
0.14
0.06
0.08
60.00
2.60
0.15
0.07
0.08
'
65.00
2.47
0.15
0.08
0.07
-----------------------------------------------------
THE REQUIRED POND SIZE = .0847646 ACRE -FT
THE RAINFALL DURATION FOR THE ABOVE POND STORAGE= 35 MINUTES
3, 70Z ew. fit.
1
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DETENTION POND BASIN B HIGH WATER LINE
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VOL. = 1/3 (AREA ABOVE) (DIFFERENCE IN COUNTOUR ELEV.)
2. FOR THE REMAIMDER OF THE VOLUMES BETWEEN CONTOURS (SECTION 9.2)
VOL. = DEPTH/6 (A + 4AB mean + B)
3. HWL= (VOL.REQ. —VOL.LOW CUML)*6/(AREA LOW+4*AVG.AREA+AREA HIGH)
ORIFICE SIZING
ORIGINAL DESIGN DATA
0.90 = Allowable Des. Release Rate cfs
54.80 = Flowline Orifice Elevation ft
0.65 = Orifice Coefficient C
2.15 = Avaliable Driving Head ft
NOTE:1. HORZ. PLATES WILL BE PLACED 6'
BELOW GRATE
2. VERT. PLATES WILL BE PLACED
AT PIPE FLOWLINE
11 VERT. CIRCULAR PLATE 11
J
i�47I? W1�6)rr
%A J ( le, a` 3� �Ax'p
' G ST 4 FIRE LINE 57.4•
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,►' �� 4�i. 3 GREASE 7R^P
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• SPECIAL NOTES -
Vertical and Horizontal locations of water, sanitary sewer and electric lines must-. be
`.field.verified,before beginning site work or cutting Lemay for pipe installation
2. The Cit of Fo
Y rt Collins ,hall not be responsible fGr maintenance of the
L , . ties, Includinq t!1e 12ling wi+l,.ir +I,e +,w,. 4- w;n1.� _r drainage facile -
_.SCALE: ZO
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DETENTION POND BASIN B 1 HIGH WATER LINE
A Ill
HATTLE4 OPERA
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m.. EPA a . u .m... Wil
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FLO
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ORIFICE SIZING
oruloEvu wu
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VERT. CIRCULAR PLATE
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