HomeMy WebLinkAboutSANDCREEK ESTATES - MINOR SUBDIVISION - 56-94 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTlucfY E -Z
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UDINLET: INLET HYDARULICS AND SIZING
DEVELOPED BY
DR. JAMES GUO, CIVIL ENG DEPT. U OF COLORADO AT DENVER
SUPPORTED BY METRO DENVER CITIES/COUNTIES AND UD&FCD
- ---------------------------------------------------------------------------
USER:Stewart and Associates -Ft Collins Colorado....... .....................
ON DATE 11-16-1994 AT TIME 09.:40:04
*** PROJECT TITLE: E-1 Capacity
*** CURB OPENING INLET HYDRAULICS AND SIZING:
INLET ID NUMBER: 0
INLET HYDRAULICS: IN A SUMP.
GIVEN INLET DESIGN INFORMATION:
GIVEN CURB OPENING LENGTH (ft)= 12.00
HEIGHT OF CURB OPENING (in)= 6.00
INCLINED THROAT ANGLE (degree)= 45.00
LATERAL WIDTH OF DEPRESSION (ft)= 2.00
SUMP DEPTH (ft)= 0.00
Note: The sump depth is additional depth to flow depth.
STREET GEOMETRIES:
STREET
LONGITUDINAL
SLOPE (%) =
0.50
STREET
CROSS SLOPE
M =
2.00
STREET
MANNING N
=
0.016
GUTTER
DEPRESSION
(inch)=
2.00
GUTTER
WIDTH
(ft) =
1.50
STREET FLOW HYDRAULICS:
WATER SPREAD ON STREET (ft) = 19.38
GUTTER FLOW DEPTH (ft) = 0.55
FLOW VELOCITY ON STREET (fps)= 2.77
FLOW CROSS SECTION AREA (sq ft)= 3.91
GRATE CLOGGING FACTOR M = 50.00
CURB OPENNING CLOGGING FACTOR(%)= 10.00
INLET INTERCEPTION CAPACITY:
IDEAL INTERCEPTION CAPACITY (Cfs)= 14.80
BY FAA HEC-12 METHOD: DESIGN FLOW (cfs)= 10.90
FLOW INTERCEPTED (cfs)= 10.90
CARRY-OVER FLOW (cfs)= 0.00
BY DENVER UDFCD METHOD: DESIGN FLOW (cfs)= 10.90
FLOW INTERCEPTED (cfs)= 10.90
CARRY-OVER FLOW (cfs)= 0.00
j Nu_r L
- -- - - -- - - - - - - -- - -- - - - - - - - ---- - -- - -- - -- - --- - - - - - - - - - -- - - -- - -- -- - --- - - -- - - --- - - -
UDINLET: INLET HYDARULICS AND SIZING
DEVELOPED BY
DR. JAMES GUO, CIVIL ENG DEPT. U OF COLORADO AT DENVER
SUPPORTED BY METRO DENVER CITIES/COUNTIES AND UD&FCD
- ---------------------------------------------------------------------------
USER:Stewart and Associates -Ft Collins Colorado ..............................
ON DATE 11-16-1994 AT TIME 09:35:19
*** PROJECT TITLE: E-1 Capacity
***. CURB OPENING INLET HYDRAULICS AND SIZING:
INLET ID NUMBER: 0
INLET HYDRAULICS: IN A SUMP.
GIVEN INLET DESIGN INFORMATION:
GIVEN CURB OPENING LENGTH (ft)= 4.00
HEIGHT OF CURB OPENING (in)= 6.00
INCLINED THROAT ANGLE (degree)= 45.00
LATERAL WIDTH OF DEPRESSION (ft)= 2.00
SUMP DEPTH (ft)= 0.00
Note: The sump depth is additional depth to flow depth.
STREET GEOMETRIES:
STREET
LONGITUDINAL
SLOPE (%) =
0.50
STREET
CROSS SLOPE
(%) =
2.00
STREET
MANNING N
=
0.016
GUTTER
DEPRESSION
(inch)=
2.00
GUTTER
WIDTH
(ft) =
1.50
STREET FLOW HYDRAULICS:
WATER SPREAD ON STREET (ft) = 8.84
GUTTER FLOW DEPTH (ft) = 0.34
FLOW VELOCITY ON STREET (fps)= 1.95
FLOW CROSS SECTION AREA (sq ft)= 0.94
GRATE CLOGGING FACTOR (%)= 50.00
CURB OPENNING CLOGGING FACTOR(%)= 10.00
INLET INTERCEPTION CAPACITY:
IDEAL INTERCEPTION CAPACITY (cfs)= 3.52
BY FAA HEC-12 METHOD: DESIGN FLOW (cfs)= 1.85
FLOW INTERCEPTED (cfs)= 1.85
CARRY-OVER FLOW (cfs)= 0.00
BY DENVER UDFCD METHOD: DESIGN FLOW (cfs)= 1.85
FLOW INTERCEPTED (cfs)= 1.85
CARRY-OVER FLOW (cfs)= 0.00
--------------------------
UDINLET: STREET CAPACITY ANALYSIS
DEVELOPED BY DR. JAMES GUO, CIVIL ENG, U OF COLORADO AT DENVER
SUPPORTED BY METRO DENVER CITIES/COUNTIES AND UD&FCD POOL FUND STUDY
- ----------------------------------------------------------------------------
R=:Stewart and Associates -Ft Collins Colorado ..............................
ON DATE 11-16-1994 AT TIME 08:14:15 g,2Nw,3c�P N �a�rc r�
*** PROJECT TITLE: STREET FLOW
*** STREET GUTTER HYDRAULICS
GIVEN GUTTER GEOMETRIES:
LONGITUDINAL SLOPE (%) = 0.40
CROSS SLOPE M = 2.00
DEPRESSION AT GUTTER (inch)= 2.00
GUTTER WIDTH (feet)= 1.50
STREET MANNING ROUGHNESS N = 0.016
THE MAXIMUM ALLOWABLE WATER SPREAD(ft)= 18.00
CURB HEIGHT (inch)= 6.00
STREET UNDER IDEAL HYDRAULIC CONDITION:
STREET CAPACITY IS DICTATED BY -- THE CURB HEIGHT
PEAK RUNOFF FLOW RATE (cfs)= 6.53
FLOW CARRIED BY GUTTER (cfs)= 1.95
FLOW CARRIED BY STREET (cfs)= 4.58
WATER SPREAD ON STREET (ft) = 16.67
GUTTER FLOW DEPTH (in) = 6.00
AVERAGE FLOW VELOCITY (fps)= 2.25
THE STREET CAPACITY REDUCTION FACTOR= 0.80
STREET GUTTER -FULL CAPACITY (cfs)= 6.53
STREET ALLOWABLE CAPACITY (cfs)= 5.23
STREET UNDER ALLOWABLE HYDRAULIC CONDITION:
PEAK RUNOFF
FLOW RATE
(cfs)=
5.23
FLOW CARRIED
BY GUTTER
(cfs)=
1.73
FLOW CARRIED
BY STREET
(cfs)=
3.50
WATER SPREAD
ON STREET
(ft) =
15.22
GUTTER FLOW
DEPTH
(in) =
5.65
AVERAGE FLOW
VELOCITY
(fps)=
2.14
STREET ALLOWABLE CAPACITY=SMALLER ONE BETWEEN
IDEAL CAPACITY AND REDUCTION FACTOR*GUTTER-FULL CAPACITY.
*** SUMMARY OF HYDRAULIC GRADIENT LINE ALONG SEWERS
------------------------------
SEWER
SEWER
SURCHARGED
ID NUMBER
LENGTH
LENGTH
FEET
FEET
------------------------------
40.00
80.00
0.00
30.00
36.00
36.00
20.00
199.00
0.00
10.00
112.00
0.00
------------------------------------------------
CROWN ELEVATION
WATER ELEVATION
FLOW
UPSTREAM
DNSTREAM
UPSTREAM
DNSTREAM
CONDITION
FEET
FEET
FEET
FEET
------------------------------------------------
64.10
63.30
63.76
63.50
JUMP
64.50
64.14
64.54
63.76
PRSS'ED
67.65
65.06
67.07
64.54
JUMP
71.25
67.78
70.67
67.07
JUMP
PRSSIED=PRESSURED FLOW; JUMP=POSSIBLE HYDRAULIC JUMP; SUBCR=SUBCRITICAL FLOW
*** SUMMARY OF ENERGY GRADIENT LINE ALONG SEWERS
-------------------------------
UPST
MANHOLE
SEWER
SEWER
MANHOLE
ENERGY
FRCTION
ID NO
ID NO.
ELEV FT
FT
-------------------------------
40.0
4.00
64.63
0.99
30.0
3.00
65.46
0.60
20.0
2.00
67.54
2.07
10.0
1.00
71.56
4.00
----------------------------------------------
JUNCTURE LOSSES
DOWNST MANHOLE
BEND
BEND
LATERAL
LATERAL
MANHOLE
ENERGY
K COEF
LOSS FT
K COEF
LOSS FT
ID
FT
----------------------------------------------
0.25
0.14
0.00
0.00
5.00
63.50
0.25
0.23
0.00
0.00
4.00
64.63
0.25
0.02
0.00
0.00
3.00
65.46
0.25
0.02
0.00
0.00
2.00
67.54
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.
*** SUMMARY OF SEWER HYDRAULICS
NOTE: THE GIVEN FLOW DEPTH -TO -SEWER SIZE RATIO= .8
-------------------------------------------------------------------------------
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)
-------------------------------------------------------------------------------
40.00
4.00
5.00
ROUND
20.26
21.00
21.00
0.00
30.00
3.00
4.00
ROUND
19.83
21.00
18.00
0.00
20.00
2.00
3.00
ROUND
10.30
15.00
15.00
0.00
10.00
1.00
2.00
ROUND
8.75
15.00
15.00
0.00
DIMENSION UNITS FOR ROUND AND ARCH SEWER ARE IN INCHES
DIMENSION UNITS FOR BOX SEWER ARE IN FEET
REQUIRED DIAMETER WAS DETERMINED BY SEWER HYDRAULIC CAPACITY.
SUGGESTED DIAMETER WAS DETERMINED BY COMMERCIALLY AVAILABLE SIZE.
FOR A NEW SEWER, FLOW WAS ANALYZED BY THE SUGGESTED SEWER SIZE; OTHERWISE,
EXISTING SIZE WAS USED
-------------------------------------------------------------------------------
SEWER
DESIGN
FLOW
NORMAL
NORAML
CRITIC
CRITIC
FULL
FROUDE
COMMENT
ID
FLOW Q
FULL Q
DEPTH
VLCITY
DEPTH
VLCITY
VLCITY
NO.
NUMBER
CFS
CFS
FEET
FPS
FEET
FPS
FPS
-------------------------------------------------------------------------------
40.0
14.4
15.9
1.31
7.48
1.41
6.95
5.99
1.17
V-OK
30.0
13.6
10.5
1.50
7.70
1.35
8.60
7.70
0.00
V-OK
20.0
2.7
7.4
0.52
5.55
0.67
20.49
2.20
1.56
V-OK
10.0
2.7
11.4
0.41
7.61
0.67
4.07
2.20
2.44
V-OK
FROUDE 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)
----------------------------------------------------------------------
40.00
1.00
62.35
61.55
2.00
2.20
OK
30.00
1.00
63.00
62.64
1.60
1.96
OK
20.00
1.30
66.40
63.81
1.95
1.04
OK
10.00
3.10
70.00
66.53
5.45
1.82
OK
OK MEANS BURIED DEPTH IS GREATER THAN REQUIRED SOIL COVER OF 1 FEET
C,c";r ( 'T
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
COLLINS-COLORADO)......:.....................
ON DATA 11-16-1994 AT TIME 10:34:53
*** PROJECT TITLE :
Revised UDSEWER run
*** RETURN PERIOD OF FLOOD IS 2 YEARS
RAINFALL INTENSITY FORMULA IS GIVEN
*** SUMMARY OF HYDRAULICS AT MANHOLES
----------------------------------------------------------------------
MANHOLE
CNTRBTING
RAINFALL
RAINFALL
DESIGN
GROUND
WATER
ID NUMBER
AREA * C
DURATION
INTENSITY
PEAK FLOW
ELEVATION
ELEVATION
MINUTES
INCH/HR
CFS
FEET
FEET
----------------------------------------------------------------------
5.00
0.00
0.00
0.00
14.40
65.50
63.50
4.00
0.00
0.00
0.00
14.40
66.10
63.76
3.00
0.00
0.00
0.00
13.60
66.10
64.54
2.00
0.00
0.00
0.00
2.70
69.60
67.07
1.00
0.00
0.00
0.00
2.70
76.70
70.67
OK MEANS WATER ELEVATION
IS LOWER THAN GROUND ELEVATION
1r4
COMMENTS
OK
OK
OK
OK
OK
�r ES Kt- . ooT
I
Sou C�K viLu.44 TLL
SC,Nt 1t�1 �.TI C
-PNl.fi1' 27 •�s
Z TC- "IPoo.
Firs IID „ L
I1� KT
0
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8D["� ZI"�C�
NOTES:
Tfl I�OT
TT3 114
14.4c-PS
- Catch basins are modeled as single manholes with specified
design flows based on Rational Method spread sheets design
points.
- All design sizing assumes a fully developed Sand Creek
- Manhole # 5 is a dummy outlet structure to simulate the
outlet piping
- All interconnecting piping is 15" at 1% slope, except as
noted
- Manhole numbering and sewer numbering corrospond to UDSEWER
JAGL-3fu.c SCtSiW1E.0NT
STEWART&&SSOCIATES
Consulting Engineers and Surveyors
103 S. MELDRUM, FORT COLLINS, CO 80521
PH. 482-9331 FAX 482-9382
By: Date: Ik— Client: �vsS 1�o5�r Sheet No. of�
Project: t_STagrF:& Mtu02 5�g�mr�,ro
Subject: )re (Z' "i-PLCT "Z (a 2 usH- LJl�coxl
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HYDRAULIC DESIGN ELEMENTS FOR
SANDCREEK ESTATES
DRAINAGE CRITERIA MANUAL
RUNOFF
0
IL
50
30
I— 20
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w
U
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a 10
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VELOCITY IN FEET PER SECOND
FIGURE 3-2. ESTIMATE OF AVERAGE FLOW VELOCITY FOR
I 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
No Text
9
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STE V VART&ASSOCIATES 103 S. 9 3DiRFAX FORT COLLINS, CO 80521
Consulting Engineers and Surveyors
82
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Consulting Engineers and Surveyors
103 S. MELDRUM, FORT COLLINS, CO 80521
PH. 482-9331 FAX 482-9382
By: Date: Client: 2� t�o��l' Sheet No. I of Z
Project:
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Time Of Concentration Calculation 100 Year Historic Storm
For: Historic Basins within and adjacent to the Sandcreek Estates Minor Sub.
By: Stewart and Associates
T(i) = 1.87(1.1-C*COD ^ 1.2 / (S ^ 1/3)
T(c) = Length / (Velocity * 60)
Yard slopes are assumed to be 2% unless otherwise noted.
0.25 = Runoff C for Basin
Sub -Basin
Type
Flow Length
feet
Slope
ft/ft
Time (i)
min
Channel
Vel. (fps)
Time (t)
min
Total Time
min
Comments
HB-A
Overland
280.0
2.0
21.1
21.8
Historic 100- earTOC
Grass Channel
0.0
0.0
0.0
0.0
Concrete Channel
60.0
0.5
1.4
0.7
HB-B
...................................
HB-C
HB-D
HB-E
HB-01
0.25 = Runoff (C) for Basin
Overland
1 290.01
2.01
21.5
29.4
Historic 100 - ear TOC
Grass Channel
0.0
0.0
0.0
0.0
Concrete Channe
662.0
0.5
1.4
7.9
0.25 = Runoff (C) for Basin
Overland
115.01
1.01
17.0
20.6
Historic 100- ear TOC
Grass Channel
0.0
0.0
0.0
0.0
Concrete Channe
635.0
2.3
3.0
3.5
0.25 = Runoff C for Basin
Overland
1225.01
2.01
18.91
1Historic
41.0
100- ear TOC
Grass Channel
1 0.01
0.01
1 0.01
0.0
Concrete Channel
1850.01
0.41
1 1.41
22.0
0.25 = Runoff (C) for Basin
Overland
297.01
5.01
16.0
16.0
Historic 100- ear TOC
Grass Channel
0.0
0.0
0.0
0.0
Concrete Channe
0.0
0.0
0.0
0.0
0.25 = Runoff (C) for Basin
Overland
180.01
1.01
21.31Historic
22.5
100- ear TOC
Grass Channel
0.01
0.01
1 0.01
0.0
Concrete Channe
100.01
0.51
1
1.41
1.2
0.63 = Runoff C for Basin
Overland
225.01
2.01
10.61
1Historic
332.6
100- ear TOC
Grass Channel
0.01
0.01
10.0
0.
Concrete Channe
1850.0
0.4
1.4
22.0
- For the purposes of this Final Drainage Report yard slopes were
assumed to be 2% while channel slopes were the weighted average.
NOVEMBER 1994
Time Of Concentration Calculation 2 Year Historic Storm
For: Historic Basins within and adjacent to the Sandcreek Estates Minor Sub.
By: Stewart and Associates
T(i) = 1.87(1.1-C*Cf)D ^ 1.2 / (S ^ 1/3)
T(c) = Length / (Velocity * 60)
Yard slopes are assumed to be 2% unless otherwise indicated. b:\schistoc
0.20 = Runoff (C) for Basin
Sub -Basin
Type
Flow Length
feet
Slope
ercent
Time (Ti)
min
Channel
Vel. (fps)
Time (Tt)
min
Total Time
Tc min
Comments
HB-A
Overland
280.0
2.0
22.4
23.1
Historic 2-year TOC
.
Grass Channel
0.0
0.0
0.0
0.0
Concrete Channel
60.0
0.5
1.4
0.7
HB-B
.............................
HB-C
HB-D
HB-E
.....................................
HB-01
0.20 = Runoff (C) for Basin
Overland
1 290.01
2.0
22.81
1
30.6
1 Historic 2-year TOC
Grass Channel
1 0.01
0.01
0.01
0.0
Concrete Channel
662.01
0.51
1.41
7.9
0.20 = Runoff (C) for Basin
Overland
115.0
1.01
18.01
1
21.6
Historic 2-year TOC
Grass Channel
0.01
0.01
0.0
0.0
Concrete Channel
635.01
2.31
3.01
3.5
0.20 = Runoff (C) for Basin
Overland
1 225.01
2.0
20.01
1
42.1
1 Historic 2-year TOC
Grass Channel
1 0.01
0.01
10.01
0.0
Concrete Channel
.1850.01
0.41
1 1.41
22.0
0.20 = Runoff (C) for Basin
Overland
1297.01
5.0
17.01
1
1
17.0
1 Historic 2-year TOC
Grass Channel
1 0.01
0.01
10.01
0.0
Concrete Channel
0.01
0.01
1 0.01
0.0
0.20 = Runoff (C) for Basin
and 180.0
1.0
22.6E
Historic 2- ear TOC
hannel 0.0
g
0.0
0.0
Channel 100.0
1 0.5
1.4
1.2
0.50 = Runoff (C) for Basin
Overland
1 225.01
2.01
13.41
1
1
35.4
1 Historic 2-year TOC
Grass Channel
10.01
0.01
1 0.0
Concrete Channel
1850.01
0.41
1 1.41
_R:Oj
22.0
- For the purposes of this Final Drainage Report yard slopes were
assumed to be 2% while channel slopes were the weighted average.
STEWART&kSSOCIATES 103 S. MELDRUM, FORT COLLINS, CO 80521
Consulting Engineers and Surveyors PH. 482-93.31 FAX 482-9382
By: Date: VS -Sq Client: RuSS —?
Sheet No. 7- of
0 OR
-
Project: -Az)
Subject: P-tr- - C) "it-t C- (07S
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STEWART&NSSOCIATES
Consulting Engineers and Surveyors
103 S. MELDRUM, FORT COLLINS, CO 80521
PH. 482-93.31 FAX 482-9382
By: Date: Client: Voss ?off -Z Sheet No. of Z
Project:
Subject: L)? D F Co , i to
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Form
SF-9
DEVELOPED RUNOFF FROM SANDCREEK ESTATES
P.U.D.
Storm Drainage System Design
AVE
11-94
(Rational Method Procedure)
FDB
This area contributes to the wdsting develo2ed storm drainage facilities serving Son dcreek Estates P.U.D.
DIRECT: RUNOFF..
TOTAL
RUNOFF
R
STREETS
...
PIPE
Design
Area
Area
ff
0C*Cl*A
Time (c)
--- s--
nte ityTR-unoff
Time (c)
Intesity
SUM of
I
Runoff
Street
S
Street
esign
Slope
Point
Design
(acres)
CoefficientRunoff
I
(min) I
(in
(min)
(in/hr)
(C X A)
(cfs)
Slope (%)
Flow (cfs)
I
Flow ICU)
SB-1
N/A
N/A
N/A
N/A'
wrt_ni 1
1971
n go I
n 5,-r,4 I
�Al 1
1
0,..,4,311
23.61,
1.681
1.1041
1.851
N/A I
N/A I
N/A
I N'
1.46
1 0 2.20 1.61
1.16 2H2.1
0.391 0.501 0.195 1 27.21 1.551 0.301 27.21 1,551 1.505 2.33
0.50
4
�32.3 1.40 2.035 Z.aS N/A 'it 7
I POND I SB-61 2.241 0.501 1.1201 11.51 2.401 2.691 11.51 2.401 1
E-1
SB-1
1 1.701
0.631
1.063
J_ 13.31
6.471
6.871
13.31
5.471
1.380
I 8.93
I NIA
I N/
HB-01
1.271
0.251
0.3181
22.51
4.881
1.551
1
1
1
1 N/A
I N/A
N/A'
i:
�NA
E-2
-2
1.461
063
eiq-lif
1.0
7.00
ii!
26f:
6.61::�:::
NA
1
N7A
-3--
SB-3
1.
0.631
0.7251
23.01
4.851
3.521
1
1
1 N/A
N/A
N/A'
sR-4
71
0631
0.2441
25.11
4.601
1.121
1
1
1 N/A
I NIA
NIA'
E-1 I RSBI -.5 0461
31 0� 1.1 4.14 1.191 30.11 4.141 2.11 1U.111 rv�A l/K
236r 0�
22. 1 01414
N/A N/A N/Al
V
I POND I SB-6 1 2.241 0.631 1.7501 9.11 8.001 11.201 9.11 8.001 1.7501 14.001 N/A N/A N/Al
Standard Form SF-9
HISTORIC RUNOFF FROM SANDCREEK ESTATES P.U.D.
CaJc'ed.By: AVE Storm Drainage System Design
Date: 11-94 (Rational Method Procedure)
Checked By: FDB This area contributes to the eAsting developed storm drainage facilities serving Sandcreek Estates P.U.D.
LeN,ow & Wilbx
Point
E-1
Design
HB-01
(acr
I
enwdion, e3cisting 4'
HB—A
I
imblebmh & Willox
E-2
HB—B
2
:rsecLion, e)dsting 12'
HB—C
1
Briarcliff & Pica
E-3
HB—D
e neaion,,gstiv'
1
TOTAL
4
.egional Detention on
POND
HB—E
Pond City of F.C.
NOTE —
0.20
—0.2541
23.8
1
-
- -F
7232
23.1
1
0.20
0.4041
30.6
1.
0.20
0.266
21.6
1
-6.20
0.1801
42.1
1
6.4-4
M�wmffam�
Time Of Concentration Calculation 100 Year Developed Storm
For: Developed Basins within and adjacent to the Sandcreek Estates Minor Sub.
By: Stewart and Associates
T(i) = 1.87(1.1-C*CQD ^ 1.2 / (S ^ 1/3)
T(c) = Length / (Velocity * 60)
Yard slopes are assumed to be 2% unless otherwise noted.
0.63 = Runoff (C) for Basin
Sub -Basin
Type
Flow Length
feet
Slope
ft/ff
Time (i)
min
Channel
Vel. (fps)
Time (t)
min
Total Time
min
Comments
SB-1
Overland
310.0
2.0
12.4
13.3
Developed 100 -earTOC
Grass Channel
0.0
0.0
0.0
0.0
Concrete Channel
75.0
0.5
1.4
0.9
SB-2
SB-3
.................................
........................................
SB-4
................. ....... .....
SB-5
.......................................
SB-6
HB-01
0.63 = Runoff (C) for Basin
Overland
260.01
3.01
9.91
11.0
Developed 100- ear TOC
Grass Channel
0.01
0.01
10.01
0.0
Concrete Channel
90.01
0.51
1 1.41
1.1
0.63 = Runoff (C) for Basin
Overland
115.0
2.01
7.6
23.0
Develo ed 100- ear TOC
Grass Channel
635.01
2.31
11.21
8.8
Concrete Channel557.0
0.5
1.4
6.6
0.63 = Runoff (C) for Basin
Overland
1 160.01
3.01
7.81
25.1
Developed 100- ear TOC
Grass Channel
10.01
0.01
0.0
0.0
Concrete Channel
1455.01
0.51
1.4
17.3
0.63 = Runoff (C) for Basin
Overland
173.0
3.0
8.1
30.1
Develo led 100- ear TOC
Grass Channel
0.0
0.0
0.0
0.0
Concrete Channe
1850.0
1 0.4
1.4
22.0
0.63 = Runoff (C) for Basin
Overland
220.01
3.01
9.11
9.1
Developed 100- ear TOC
Grass Channel
1 0.01
0.01
1 0.0
0.0
Concrete Channel
0.01
0.01
1 0.0
0.0
0.25 = Runoff C for Basin
Overland
180.01
1.01
21.31
1
22.51
Historic 100- ear TOC
Grass Channel
0.01
0.01
0.01
0
equals Developed 100- ear
Concrete Channel
100.
51
1.4
1.2
- For the purposes of this Final Drainage Report yard slopes were
assumed to be 2% while channel slopes were the weighted average.
NOVEMBER 1994
Time Of Concentration Calculation 2 Year Developed Storm
For: Developed Basins within and adjacent to the Sandcreek Estates Minor Sub.
By: Stewart and Associates
T(i) = 1.87(1.1-C*COD ^ 1.2 / (S ^ 1/3)
T(c) = Length / (Velocity * 60)
Yard slopes are assumed to be 2% unless otherwise indicated. b:\schistoc
0.50 = Runoff C for Basin
Sub -Basin
Type
Flow Length
feet(percent)
Slope
Time (Ti)
min
Channel
Vel. f s
Time (Tt)
min
Total Time
Tc min
Comments
SB-1
Overland
310.0
2.0
15.7
16.6
Developed 2-year TOC
Grass Channel
0.0
0.0
0.0
0.0
Concrete Channel
75.0
0.5
1.4
0.9
SB-2
...............................
.......... .....................
SB-3
.. ..........................
SB.-4
..............................
SB-5
.................................
SB-6
HB-01
0.50 = Runoff (C) for Basin
Overland
1 260.01
3.0
12.51
1
13.6
1 Developed 2-year TOC
Grass Channel
0.01
0.01
0.0
0.0
Concrete Channel90.0
0.5
1.4
1.1
0.50 = Runoff C for Basin
Overland
1 115.01
2.01
9.611
1Developed
25.0
2-year TOC
Grass Channel
635.01
2.31
11.2
8.8
Concrete Channel557.0
0.5
1.4
6.6
0.50 = Runoff (C) for Basin
Overland
160.0
3.0
9.8
1Develo
27.2
ed 2-year TOC
Grass Channel
0.01
0.01
1 0.0
I0.0
Concrete Channel
1455.0
I 0.5
1.4
17.3
0.50 = Runoff (C) for Basin
173.0
3.0
10.2
eveoed 2- ear TOC
nel
M
0.0
0.0
nne
1850.0
I0.4
1.4
22.0
0.50 = Runoff C for Basin
Overland
220.0
3:61
11.51
1
11.5
1 Developed 2-year TOC
Grass Channel
0.01
0.01
1 0.01
0.0
Concrete Channe
0.01
0.01
1 0.01
0.0
0.20 = Runoff (C) for Basin
Overland
1 180.01
1.01
22.61
1
23.81
Historic 2-year TOC is equal
Grass Channel
1 0.01
0.01
10.0
0.0
to the 2-year developed
Concrete Channel
100.01
0.51
1 1.4
1.2
- For the purposes of this Final Drainage Report yard slopes were
assumed to be 2% while channel slopes were the weighted average.
HYDROLOGY OF THE DEVELOPED
SANDCREEK ESTATES
FLOW
LENGTH
(FT)
100
200
300
400
500 .
600
700
800
900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2500
3000
3500
4000
4500
5000
PERFORMANCE STANDARDS FOR FORT COLLINS, COLORADO
------------------------------------------------------------------------------------
SLOPE (%)
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 6.0 7.0 8.0 9.0 10.0 20.0 30.0 40.0 50.0
-------------------------------------------------------------------------------
70.9 74.6 76.8 78.4 79.5 80.3 81.1 81.6 82.1 82.5 83.0 83.4 83.6 83.8 84.0 84.7
72..0 76.3 78.2 79.5 80.5 81.2 82.1 82.5 82.8 83.2 83.6 83.9 84.0 84.2 84.3 84.8
172.4 77.0 78:8 80.0 80.9 81.6 82.5 82.8 83.1 83.5 83.8 84.1 84.2 84.3 84.4 84.8
72.6 77.4 79.1 80.3 81.2 81.8 82.7 83.0 83.3 83.7 84.0 84.2 84.3 84.4 84.5 84.8
72.7 77.7 79.4 80.5 81.3 81.9 82.8 83.1 83.4 83.8 84.1 84.3 94.4 84.5 84.6 84.9
172.8 77.9 79.5 80.6 81.4 82.0 83.0 83.2 83.5 83.9 84.1 84.3 84.4 84.5 84.6 84.9
172.8 78.0 79:7 80.8 81.5 82.1 83.0 83.3 83.5 84.0 84.2 84.4 84.5 84.5 84.6 84.9
172.7 78.1 79.7 80.8 81.6 82.2 83.1 83.4 83.6 84.0 84.2 84.4 84.5 84.6 84.6 84.9
172.7 78.2 79.8 80.9. 81.7 82.2 83.2 83.4 83.6 84.1 84.3 84.4 84.5 84.6 84.7 84.9
72.7 78.3 79.9 81.0 81.7 82.3 83.2 83.5 83.7 84.1 84.3 84.4 84.5 84.6 84.7 84.9
72.6 78.3 79.9 81.0 81.7 82.3 83.3 83.5 83.7 84.1 84.3 84.5 84.6 84.6 84.7 84.9
172.6 78.4 80.0 81.0 81.8 82.3 83.3 83.5 83.7 84.2 84.3 84.5 84.6 84.6 84.7 84.9
72.6 78.4 80-.0 81.1 81.8 82.4 83.3 83.6 83.8 84.2 84.4 84.5 84.6 84.6 84..7 84.9
72.5 78.5 80.1 81.1 81.8 82.4 83.4 83.6 83.8 84.2 84.4 84.5 84.6 84.7 84.7 84.9
72.4 78.5 80.1 81.1 81.9 82.4 83.4 83.6 83.8 84.2 84.4 84.5 84.6 84.7 84.7 84.9
72.4 78.5 80.1 81.1 81.9 82.4 83.4 83.6 83.8 84.2 84.4 84.5 84.6 84.7 84.7.84.9
172.3 78.5 80.1 81.2 81.9 82.4 83.4 83.6 83.8 84.3 84.4 84.5 84.6 84.7 84.7 84.9
172.3 78.6 80.1 81.2 81.9 82.4 83.4 83.7 83.8 84.3 84.4 84.5 84.6 84.7 84.7 84.9
172.2 78.6 80.2 81.2 81.9 82.5 83.5 83.7 83.9 84.3 84.4 84.5 84.6 84.7 84.7 84.9
172.2 78.6 80.2 81.2 81.9 82.5 83.5 83.7 83.9 84.3 84.4 84.6 84.6 84.7 84.7 84.9
71.9 78.6 80.2 81.3 82.0 82.5 83.5 83.7 83.9 84.3 84.5 84.6 84.7 84.7 84.8
71.6 78.7 80.3 81.3 82.0 82.5 83.6 83.8 84.0 84.4 84.5 84.6 84.7 84.7 84.8
171.4 78.7 80.3 81.3 82.0 82.6 83.6 83.8 84.0 84.4 84.5 84.6 84.7 84.7 84.8
171.1 78.6 80.3 81.3 82.0 82.6 83.6 83.8 84.0 84.4.84.5 84.6 84.7 84.8 84.8
70.9 78•:6 80.3 81.3 82.0 82.6 83.7 83.9 84.0 84.4 84.6 84.6 84.7 84.8 84.8, 70.6 78.6 80.3 81.3 82.0 82.6 83.7 83.9 84.0 84.4 84.6 84.7 84.7 84.8 84.8
----------------
84.8
84.9
84.9
84.9
84.9
84.9
84.9
84.9
85.0
84.9
84.9
85.0
84.9
85.0
85.0
84.9
85.0
84.9
85.0
84.9
85.0
84.9
85.0
84.9
85.0
84.9
84.9
85.0
85.0
85.0
PAGE 24
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. . . . . . 0`O1
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
61 2.AVGL 045
HAY OR STRAW DRY MULCH
After planting grass seed, apply mulch at
a rate of Z tons acre minimum) and adequately
anchor, tack or crimp material into the soil.
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
in$][C
1.0
Maximum
Slope
Length
(q)
(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
to
25
75 . . .
. . . . . . 0.14
1.00
25
to
33
50 . . .
. . . . . . 0.17
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.
STEWART&kSSOCIATES 103 PH. S. 9 LD1RUM, FAX FORT gOLLINS, CO 80521
Consulting Engineers and Surveyors
By: Date: \\-Zk-94 Client: Sheet No. 3 of
Project: wm(L So?
Subject: G't1 n rz r r , E(zt>1 r a.. 77V"PD r o ,Z
IT'k'Ir✓ rtt75l I712,�I1 Y��U74j
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STEWART&JkSSOCIATES
Consulting Engineers and Surveyors
103 S. MELDRUM, FORT COLLINS, CO 80521
PH. 482-9331 FAX 482-9382
By: Date: l I - Z 1- `I `% Client: 2,� To�QH Sheet No. of
Project: ��.>><<�e� H arz UV\�v�ox'Z S 2;�ij1°
Subject: Z s- o t ,, fb -r> 2 DEL
c I'�2o cT
,
_.1Iry TOe4ia.>
- f
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1 1 i i
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I
STEWART&ASSOCIATES 103 S. MEL93.DRUM,
FORT COLLINS, CO 80521.
PH. 482-FAX 482-9382
Consulting Engineers and Surveyors
By: Date: I I —I Client: Sheet No. J- of :1D
Project: SbL-;i`)p;2ec--K fzt-2go-_ Miy--)tg-
Subject: (vir-1jr�CAL ---,�LS LE- D La1'
pol � i lz)t��O t�v,-Lf O'� Tts p
-�V-0,sejc,-rl A-ZeN L-Atu
J20�' IS
It
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I I: 1 I I I I I I' II I 1 l I I. ! � I I I i � I• I ', ! I I I i
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-'3
0, 64
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it
1 17-0 -T-D'
t
it
!x•`�! ! -- I -j ! i j. ! 1 i i I I i! I I j I i{ I i
0
-# -A
Effectiveness Calculation
Project: SRw�D C�¢a��Sih� Mlrao a Standard Form B
By: Stewart & Associates Completed: NAL
103 S. Meldrum
Fort Collins, Colorado 80521 Date: 1�
Erosion Control
Method
C— Factor
Value
P — Factor
Value
Comments:
ISIL71 -k't:t�
,co\
O ISO
tO ' t] k
00
,00
0100!
i'00
o. (Ftck 5l
S. �2•I �j,
HDI/SF—B:1989 4.bOo
Rainfall Performance Standard Evaluation
Project:_SAwih Akt S f , Standard Form A
By: Stewart & Associates Completed:
103 S. Meldrum
Fort Collins, Colorado 80521 Date: /Z(/174
Developed
Subbasin
Erodibility
Zone
Asb
acres
Lsb
feet
Ssb
%
Lb
feet
Sb
%
PS
%
zoo
d,s
MO
- Z
4.o1
1,25
3. o
So,-s
21.
Ae
HDI/SF—A:1989
CONSTRUCTION SEQUENCE
PROJECT: �)Apbc9 y__ •CSiriffa, MiHcy 'S,yg, STANDARD FORM C
SEQUENCE. FOR 19 J5 ONLY COMPLETED BY: DATE: I -Zj_
i. ,icate by use of a bar line or symbols when erosion control measures will be installed.
Major modifications to an approved schedule may require submitting a new schedule for
approval by the City Engineer.
YEAR
MONTH IF 1
I
------------------------- 5 _---
--- --------------- — -- ---- -- I- — --
---�- I
OVERLOT GRADING I. I I ! I _---I
I I I
WIND EROSION CONTROL I: I
Soil Roughing
Perimeter Barrier I I.
Additional Barriers
Vegetative Methods
Soil Sealant
Other I
I I!
RAINFALL 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
VEGETATIVE:
Permanent Seed Planting
Mulching/Sealant
Temporary Seed Planting`;
Sod Installation '• � �
Nettings/Mats/Blankets
Other
-- - - - - - - - - - - - - - - - - - - - - - - - - - - I - - - I I I i
STRUCTURES: INSTALLED BY (-C•_ MAINTAINED BY
VEGETATION/MULCHING CONTRACTOR
..11 T
DATE SUBMITTED 11- ZI-`j`� APPROVED BY CITY OF FORT COLLINS ON
HO =-C:1989
STEWART8&SSOCIATES 103 S. ME 3D1RF , FORT gOLLINS, CO80521
PH.Consulting Engineers and Surveyors
By: AU-0, Date: Client: �OS'C, �o�.o� Sheet No. of
Project: 1P ofL Jy�
Subject: �l 0011ov\. Co�� � (—�� IVA Iris .
I
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EROSION CONTROL COMPUTATION FOR
SANDCREEK ESTATES P.U.D.
EROSION CONTROL REPORT
The Sandcreek Estates Minor Subdivision falls within an area
of the City characterized by high rainfall erodibility and
moderate wind erodibility. This according to the published maps
in the City of Fort Collins Storm Drainage Design Criteria and
Construction Manual (SDDCCM). A single catchment area will be
analyzed including all of the 21.97 acres of onsite and offsite
area. Performance of the design will, however, be based on the
most stringent of all four sub catchments. That value, as shown
in the appendices, is 82.1 percent.
In assuming a conservative approach to the design, all of the
building areas are assumed to be started simultaneously presenting
a "worst case" scenario for exposure to erosion. Building envelopes
of 150-linear feet (l.f.)times 100-1.f. area are presumed for each
of the six structures. The total area being disturbed because of
this assumption is 2.07 acres. The remaining area 4.8.8 acres is
calculated as the grassland conditions that currently exist.
Existing residential development (offsite 13.24 acres) is included
as "sod grass." There is little difference in this assumption and
assigning basin components and weighting those to some average
value for the basin.
Silt fencing will be placed on the Southerly boundary,
downstream, of all areas of soil disturbances. Concurrently, gravel
inlet filters will be placed at all three of the inlets mentioned
in the storm drainage report. This combination of structural
measures brings the performance of the erosion control design to a
11
level of 89.2 percent, greater than the 82.1 percent required.
Page 8
Sandcreek Estates
Final Storm Drainage Report
CONCLUSIONS
The Greenbriar/Evergreen Basin has seen substantial regional
planning and construction of storm drainage facilities in the
recent past. With the area surrounding this project being almost
fully developed., little in the storm drainage design has been
demanded, rather confirmation of the adequacy of existing
conveyance elements has been the thrust of this report. No concerns
-
have arisen because of this investigation.
The project meets the City of Fort Collins SDDCCM.
Consequently, no risk to human safety or property has arisen during
project planning. It is for this reason we request your review and
approval of this development project. Should questions arise during
your review of this project, please feel free too contact Alex
Evonitz or myself so we may help in your understanding.
Respectfully,
..a„4 n,,,
Richard A. Rutherford, P.E. & L.S. #5028
: 502�
.A
4i�JJ F, & L
E
Page 7 / l BOO
Sandcreek Estates !/
Final Storm Drainage Report
As a result of this planning, the East 125-feet,the project
area is being dedicated to the City of Fort Collins for the ongoing
development of this proposed regional project. Additionally, the
one house proposed to abut the pond has a finished floor 4982-feet,
while the hwl of this pond is projected to be 4974-feet.
Basins contributing to inlet E-1 flow into the Greenbriar
Wetlands Pond, as do flows from inlet E-2. Surface runoff collected
in inlet E-3 contribute to the Greenbriar pond South of Willox.
Finally, 2.24-acres of this project flow in a sheet flow toward the
Gb-Eg East Pond that is currently under development.
Page 6
Sandcreek Estates
Final Storm Drainage Report
Thus the minor increase in flow directed to the existing 4-foot
inlet is still within the curb inlet's capacity. Only 0.46 acres of
the contributing 4.07 acre area will see an increased use. The
remainder of the basin is already fully developed.
The total runoff directed into this inlet, including the
offsite 3.61 acres, is 2.85 cfs in the minor storm event. In the
appendices this sumped curb inlet as been reviewed to ensure the
availability of the capacity.
DETENTION
No onsite detention will be developed as part of the project
being constructed at this time. Regional planning has indicated in
the "DRAFT" Greenbriar-Evergreen Basin Master Plan that basins in
the regional scheme are fully developed. The consequence of this is
that all regional facilities are sized to account for this project
(see exhibits in appendices in this report).
Three regional ponds will be collecting direct runoff from
this six lot project area. They are Greenbriar-Evergreen East
Offsite, Greenbriar and Greenbriar Wetlands. Greenbriar is fully
developed and is located South of Willox. Greenbriar Wetlands is
currently under construction as part of the Greenbriar Village III
improvements. The final regional facility is the project addressed
in the aforementioned draft report. Planning on this regional
project has reached the point of establishing a proposed high water
line (hwl)in the pond.
I
Page 5
Sandcreek Estates
Final Storm Drainage Report
Inlet E-2 is on the North flowline of Willox just West of the
Bramblebush/Willox intersection. Upgrading of the original 4-foot
inlet was undertaken during improvements for Sandcreek Village III
Replat approved in 1993. Then a 12-foot inlet was constructed to
manage the new direct runoff from the intensified residential land
use. Noteworthy is that the design for that inlet showed a need for
a slightly over 10-foot long curb •inlet, and as a result, a 12-foot
inlet was constructed. This has provided additional inlet capacity
that had not been used.
Prior to this development, 9.8 cfs were directed into this
inlet, with 1.2 cfs coming from the currently undeveloped project
area. Because of the intensified use on this project, 10.9 cfs of
direct runoff will now be captured by this existing 12-foot curb
inlet. Capacity is available and is the result of the nearly two
additional feet of inlet length mentioned above (see the appendices
for details).
The final inlet of interest is identified as E-3 at the
Briarcliff/Pica intersection in the East flowline of Briarcliff. A
4-foot inlet is existing at that location which is
± 1850-feet from this project. The street slopes on Bramblebush and
the continuation to Briarcliff are low (0.4 percent). This length
and flat slope are a benefit in establishing direct runoff volumes
from the contributing basin. These result in a long times of
concentration, which reduces the imposed storm intensity for the
Rational Method of analysis.
Page 4
Sandcreek Estates
Final Storm Drainage Report
Minor design storm flows have been added to existing adjacent land
use runoff to ensure hydraulic capacity is available in all
existing storm drainage structures.
HYDRAULICS
There is no true hydraulic design elements part of this
project, rather a verification of existing capacities was in order.
All existing curb inlets have had sizes field checked and location
verified. In the area of the greatest point of collection, the pipe
conveyance was also confirmed. The results of this analysis by
UDSEWER are shown in the appendices and showed that all offsite
piping can handle the modest increases in flow.
Three inlets have had their capacity confirmed and are
identified as inlets E-1, E-2 and E-3. Inlet E-1 is existing in the
North flowline of Willox between Agape Way and Redwood Streets. It
is a V curb opening with a sump condition available. When reviewed
by "UDINLET" which is software approved by Urban Storm Drainage the
inlet has an actual capacity of 3.85 cubic feet per second (cfs).
The actual 2-year flow direct toward this inlet following
development is 1.85 cfs which is well within the available
capacity. The 15-inch pipe exiting the inlet and flowing South has
capacity far more than the 1.85.cfs directed toward it.
Page 3
1; Sandcreek Estates
Final Storm Drainage Report
DEVELOPED CONDITION
10,
The conditions following development will change very little
since the project area is small (six lots). Because of the limited
nature of the development, a standard runoff coefficient was used
to determine direct runoff. This coefficient from the City of Fort
Collins Storm Drainage Design Criteria and Construction Manual
(SDDCCM) is C = 0.50 for this type of residential development. The
necessity to establish weighted C values for each specific basin
would yield little in regard to design function.
Six onsite basins and two offsite basins have been included
for analysis. The following table will identify the developed basin
constants used in the Rational Method of analysis for direct
runoff.
DEVELOPED BASIN COMPONENTS
BASIN
AREA
RUNOFF "C"
TOC 2
Q 2
COMMENTS
(ac)
2-YEAR
(min)
(cfs)
TOC 100
Q 100
SB-1
1.70
0.50
16.6
1.70
Inlet E-1 to
13.3
6.87
Greenbriar Wetlands
SB-2
1.46
13.6
1.61
Inlet.E-2 to
11.0
6.39
Greenbriar Wetlands
SB-3
1.16
25.0
0.95
"
23.0
3.52
SB-4
0.39
27.2
0.30
"
25.1
1.12
SB-5
0.46
32.3
0.32
Inlet E-3 to
30.1
1.19
Greenbriar
SB-6
2.24
11.5
2.69
Surface flow to GB-EG
9.1
14.0
East
HB-01
1.27
0.20
23.8
0.43
Inlet E-1 to
22.5
1.55
Greenbriar Wetlands
HB-02
1 3.61
1 0.50
1 42.10
2.53
Inlet E-3 Greenbriar
Page 2
Sandcreek Estates
Final Storm Drainage Report
HYDROLOGY
Existing Conditions
Currently the site is covered with a well established growth
of rangeland grasses and weeds. Slopes are in the 2-5 percent range
and generally run down from the ditch right-of-way toward the
South. Collection of this historic runoff is in three existing
inlets that are part of adjacent developments. Additionally a small
amount of surface runoff is directed toward the proposed Gb-Eg East
facility. Surface runoff moves into one of three regional detention
facilities of which one exists and two are either under
construction or proposed. The following table will summarize
present condition.
HISTORIC BASINS AND POINTS AREAS OF DETENTION
BASIN
AREA
(ac)
POINT OF
COLLECTION
REGION FACILITY
NAME
CURRENT STATUS
HB-A
1.16
INLET E-1
GREENBRIAR WETLAND
UNDER
CONSTRUCTION
HB-B
2.02
INLET E-2
HB-C
1.33
INLET E-2
HB-D
0.90
INLET E-3
GREENBRIAR
EXISTING
HB-E
2.02
REGIONAL
GB-EG EAST OFFSITE
PROPOSED
HB-01
1.27
INLET E-1
GREENBRIAR WETLAND
UNDER
CONSTRUCTION
HB-02
3.61
INLET E-3
GREENBRIAR
EXISTING
The same historic points of collection will be maintained except
for the newly intensified use.
Final Storm Drainage Report
for
Sandcreek Estates Minor Subdivision
GENERAL SITE CONDITIONS
The project is located in the Northeast quadrant of Fort
Collins in the Southeast 1/4 of Section 36, Township 8 North, Range
69 West of the Sixth P.M., City of Fort Collins, County of Larimer,
State of Colorado. This positions the site on the North side of
East Willox Lane (Willox), and North of Bramblebush Street in the
Greenbriar Village Subdivision. This location is in the Greenbriar-
Evergreen Basin Master Drainage Plan that is currently being
revised.
Project boundaries. are the Larimer and Weld Canal (Canal) on
the North, Sandcreek Village 3rd on the South (the Third). East is
the proposed Greenbriar-Evergreen East (Gb-Eg East) Offsite
Detention Facility. West is undeveloped grassland. The property to
be improved would best be described as a strip of ground next to
the Canal. All storm drainage facilities have been constructed as
part of the development activity on the adjacent parcels. Thus, no
storm drainage facility construction will be a direct result of
this current development proposal. Verification of the capacity for
existing facilities will be required, however, as part of this
development report.
l Spoalding Lo Lono o tea`
Linden-
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c
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CaCh�'�'—----_---- Trujillo St -- --
A
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Buckin ham St
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Final.Storm.Drainage Report
for
SANDCREEK ESTATES MINOR SUBDIVISION
�Uy
November 1994
''IT
IM,,
Stewart & Associates
Consulting Engineers and Surveyors
103 South Meldrum Street
Fort Collins, Colorado 80521
(303) 482-9331
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EXHIBITS FOR
SANDCREEK ESTATES P.U.D.
Land Use and Drainage Pattern Assumptions for Developed Conditions
rWithout specific development plans for most areas in the Greenbriar-Evergreen drainage
it was necessary to make assumptions concerning future land use conditions iri most
1,ubbasins. These assumptions were based on current land use zoning maps provided by the City
of Fort Collins and Larimer County; they are summarized in the following paragraphs and in
Table 4.1. Included in the following paragraphs are the assumptions inherent to the developed
condition hydrologic analysis which were prescribed by the City Stormwater Utility. It is noted
that drainage facilities which are referred to as proposed have been previously designed by others,
while the facilities which are termed conceptual were newly designed to either conceptual or
preliminary levels, as necessary, for this study.
Basin OA. The basin was assumed to be fully developed with low density residential
housing and an estimated imperviousness of 40 percent. On -site detention would not be
required for this basin; all storm runoff (up to that generated by the 100-year event)
would be conveyed to the existing Evergreen East Pond. Outflows from this pond would
enter the proposed downstream outlet channel and be conveyed across Lemay Avenue via
an existing 42-inch Permalock pipe to the Greenbriar Outfall pipe.
Basin OB. The basin was assumed to be fully developed with low density residential
housing and an estimated imperviousness of 40 percent. On -site detention would be
required for this basin. The allowable release from this basin is 12 cfs, or 0.25 cfs/acre.
The designated release point for Basin OB is the proposed channel located at the northeast
corner of the basin, directly south of the Evergreen East Pond. The detention volume
required for the basin, in order to meet the prescribed release rate, was estimated to be
8.3 acre-feet.
Basin IA. This basin was assumed to be fully developed with low and medium density
residential housing at 82 and 18 percent levels, respectively; the result being an overall
imperviousness of about 41 percent. On -site detention would not be required for this
basin; all storm runoff would be conveyed to the proposed Greenbriar Wetland Pond.
Basin 1B. The basin was assumed to remain completely pervious; the basin has been .
acquired by the City for the purpose of enhancing the wetland as well as constructing the
proposed Greenbriar Wetland Pond. This pond would accept inflows from Basins IA
through 1F and provide full retention of the runoff volume from the 100-year event;
delayed release of stored water to the Redwood Pond would be provided via an outlet
pipe (conceptual) to be located along Redwood Street.
Basin 1C. This basin was also assumed to remain completely pervious; the basin has
been developed by the City as the western portion of Greenbriar Park. On -site detention
would not be required for this basin; however, a small detention pond has been provided
near the southwest corner of the park. (The effect of this pond has been included in the
proposed condition hydrologic analysis.) All storm runoff from the basin, in the form of
18
AW
Q/G 19q
GREENBRIAR-EVERGREEN BASIN
MASTER DRAINAGE PLAN
PREPARED FOR:
City of Fort Collins
Stormwater Utility .
235 Mathews
Fort Collins, CO 80522
PREPARED BY:
Lidstone & Anderson, Inc.
736 Whalers Way, F-200
Fort Collins, CO 80525
(LA Project No. COTST05.4)
and
TST, Inc.
748 Whalers Way, Building D
Fort Collins, CO 80525
STEWART&ASSOCIATES
Consulting Engineers and Surveyors
103 S. MELDRUM, FORT COLLINS, CO 80521
PH. 482-9331 FAX 482-9382
By: ��' �' Date: 75-JJ Client: StAE)Z-I,kN "-Dwtt?> Sheet No. of
Project: \II t u 'E\ 1- ��
Subject: C7v e2 tv�� rJL�J It lox UJ rtOIJ Ja i) 1-k�' C��
i \NJILWX i71-71-rl:.e 0 1_0. ) r011J�'
GIwM . —, Qlo� _C3 e +Zta Sa �eccrrt �.IC
LaO
All A^• TO-ZT-LZ. A'V. S j-i J..-N
I I � f�T (� ,Jf' I I�IV.JK r`� 7�.C.�q(� 1:La^Z O•t`'RNi�� p..J WM-1
ASs,w.a� +�uuJ !JO Cr IZ2 1►J ? i fi� L-)tU_ P(-l. o�(LTo? �t_L0X
. —r2� P�►-�yv �w 12. W � �z- �oeFF . �- Z. , 7 L �a.e�r�� ��3' -1.� �I� A,��a �)
L.3 - IZ•S
�ili 09 � .Z �-T. k =.2
I I I i I I
STL1'� �.� . ��-r.4S F'c J`F-1Z�ST TO t' �•.. = . Z
.Z -i''1"/Cops) 4+4T, 4LQ
I,S
�ZS/,1�5� Z = (I,o
p,-T- Tr�-� (Oc�> �p l � 1 1..) I..`-1 l.l_ l o X T � C 6 J'.c�� �F•-'?�c .
DESIGN RUNOFF COMPUTATIONS FROM RATIONAL METHOD
Q = C x Cf x I x A
SUBBASINTIME OPCONCENTRATION: ......
D. Pnt.
Slope
(%)
C Cf
I
Length
I (feet)
Overl-Tc
(min.)
Vel.Chan
(ft/sec.)
Tc Chan.
(min.)
Tc Total
(min.)
COMMENTS
AREA SB'-g
2.00
0.50
85.00
8.2
2 yr
1.801
790.00
2.60
5.1
13.3
LNGST. OVERL.+CHANNEL
2.001
0.63
85.00
6.5
100 yr
1.80
790.00
2.60
5.1
A 1:61
LNGST.OVERL.+CHANNEL
0.50 = Runoff C
1.00 = Cf 2,10
1.25 =Cf 100
D. Pnt.
Area
(cfs
acres)
C * Cf
1(2yr.)
(intho
1(10yr.)
(in/hj
I 1(100yr.)
on/ho
Basin I Comb.0
cfs
(cfs' =L
COMMENTS
SB-9
2.001
0.50
2.451_
1
2.451
2 yr. runoff
0.501
4.301
4.3011
4:31
10 yr. runoff
1 0.631
1 7.00
8.75jl
100 yr. runoff
0.50 = C 1.00 =Cf(2,10) 1.25 =Cf(100)
Total in this Development
Weighted Runoff C Computation
Design Point B (Sand Creek Court Pan)
Basins SB - 1, 2, 3
3.0
2 yr. runoff (cfs)
4:61
- 10 yr. runoff (cfs)
9.51
100 yr. runoff (cfs)
H I �� I.. �� :: 1-9.81 2 yr. runoff (cfs)
Y Design Point A (inlet & Encroachment Design Flows) 16.71 10 yr. runoff (cfs)
D Basins SB- 1, 2, 3, 4, 5, 7, 8, 9 33.61 100 yr. runoff (cfs)
A
L1 Design Point C (Encroachment Design) 1
L Basins SB-7. 9
3.6
2 yr. runoff (cfs)
.6.41
10 yr. runoff (cfs)
-12.91
100 yr. runoff (cfs)
L1
M
M
Design Point D (Agape Way Pan Design)
Basins SB-7
-.1.2
2 yr.
runoff (cfs)
2.1
10
yr. runoff (cfs)
4.21
100
yr, runoff (cfs)
10.61 2 yr. runoff (cfs)
Total Design Flow for Hydraulics (IA to IB to Retn.) 18,11 10 yr. runoff cfs
All Basins Included Design Flows 36.31 100 yr. runoff (cfs)
Pipe Design Flow (Agape Way to Inlet C)
SB-6
0.8
2 yr. runoff (cfs)
.1c41
10 yr. runoff (cfs)
2.71
100 yr. runoff (cfs)
M
Final Storm Drainage Report
Replat of Sandcreek Village III P.U.D.
STEWART&�SSOCIATES
Consulting En3ineers and Surveyors
103 South NeAtwm SLwei
Toict COtQ&Lz, Coeo4ado 80521
3031482-9331
REFERENCED REPORTS FOR
SANDCREEK ESTATES
-------------------------------------- -------------------------- ---------------
UDINLET: INLET HYDARULICS AND SIZING
DEVELOPED BY
DR. JAMES GUO, CIVIL ENG DEPT. U OF COLORADO AT DENVER
SUPPORTED BY METRO DENVER CITIES/COUNTIES AND UD&FCD
- ---------------------------------------------------------------------------
USER:Stewart and Associates -Ft Collins Colorado ..............................
ON DATE 11-16-1994 AT TIME 08:19:19
*** PROJECT TITLE: 4' Inlet Capacity
*** CURB OPENING INLET HYDRAULICS AND SIZING:
INLET ID NUMBER: 10
INLET HYDRAULICS: IN A SUMP.
GIVEN INLET DESIGN INFORMATION:
GIVEN CURB OPENING LENGTH (ft)= 4.00
HEIGHT OF CURB OPENING (in)= 6.00
INCLINED THROAT ANGLE (degree)= 45.00
LATERAL WIDTH OF DEPRESSION (ft)= 2.00
SUMP DEPTH (ft)= 0.00
Note: The sump depth is additional depth to flow depth.
STREET GEOMETRIES:
STREET
LONGITUDINAL
SLOPE (%) =
0.40
STREET
CROSS SLOPE
M =
2.00
STREET
MANNING N
=
0.016
GUTTER
DEPRESSION
(inch)=
2.00
GUTTER
WIDTH
(ft) =
1.50
STREET FLOW HYDRAULICS:
WATER SPREAD ON STREET (ft) = 11.50
GUTTER FLOW DEPTH (ft) = 0.40
FLOW VELOCITY ON STREET (fps)= 1.91
FLOW CROSS SECTION AREA (sq ft)= 1.48
GRATE CLOGGING FACTOR M = 50.00
CURB OPENNING CLOGGING FACTOR(%)= 10.00
INLET INTERCEPTION CAPACITY:
IDEAL INTERCEPTION CAPACITY (cfs)= 4.37
BY FAA HEC-12 METHOD: DESIGN FLOW (cfs)= 2.85
FLOW INTERCEPTED (cfs)= 2.85
CARRY-OVER FLOW (cfs)= 0.00
BY DENVER UDFCD METHOD: DESIGN FLOW (cfs)= 2.85
FLOW INTERCEPTED (cfs)= 2.85
CARRY-OVER FLOW (cfs)= 0.00