HomeMy WebLinkAboutDrainage Reports - 04/01/1998SHEAR
Final Drainage and Erosion Control Report
for
AURORA HILLS SUBDIVISION
Larimer County (Ft. Collins), Colorado
Prepared for:
Frederick Land Surveying
1528 North Lincoln Avenue
Loveland, Colorado 80538
At
Prepared by:
SHEAR ENGINEERING CORPORATION
Project No: 1005-42-94
Date: April, 1998
4836 S. College, Suite 12 Ft. Collins, CO 80525 (970) 226-5334 FAX (970) 282-0311
I hereby state that this Report for the final drainage design of "Aurora Hills Subdivision", was
prepared under my direct supervision for the owners the a eet or exceed the criteria in
the Larimer County Storm -Water Management Manual for th o nets thereof.
,o o`"AO0 RE611 o
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------ - ------------- ---------- ---------------------
E ; m 2�262 o - Brian W. Shear, P.E.
Registered Professional Engineer
��,�. ; _.•a`+<a State of Colorado No: 20262
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PAGE 1
Final Drainage and Erosion Control Report
Project No. 1005-42-95
1 I Z 0 O'10)1110 M [a]►`F
This report presents the pertinent data, methods, assumptions, references and calculations
used in analyzing and preparing the final drainage and erosion control design for the Aurora
Hills Subdivision.
L GENERAL LOCATION AND DESCRIPTION:
A. Location:
1. Aurora Hills Subdivision is located in the Southeast 1/4 of Section 11, T6N, R69W of
the 6th Principal Meridian, Larimer County, Colorado.
2. More specifically, Aurora Hills Subdivision is located on the south side of Skyway
Drive approximately 1/4 mile west of U.S. Highway 287 at the Southeast corner of
the intersection of Skyway Drive and Constellation Drive.
3. Aurora Hills Subdivision is bounded by Skyview South Second Filing on the west,
Skyview First Addition to the North, and unplatted land to the east and south.
4. Foothills Gateway is located on the south and east of the site. An access to Foothills
Gateway is located east of the property line of Aurora Hills Subdivision.
B. Description of Property:
1. Aurora Hills Subdivision property covers approximately 7.50 acres according to the
Final Plat of Aurora Hills Subdivision.
2. The site is currently covered with native grasses.
3. Development of the site will consist of 32 single family homes and the necessary
infrastructure to service them. A portion of the property will be dedicated as a
Drainage, Access, Utility and open space easement for detention purposes. This area
is designated as Tract A on the Final Plat and is located in the extreme Northeast
corner of the site.
H. DRAINAGE BASINS AND SUB -BASINS:
A. Major Basin Description:
1. Aurora Hills Subdivision is located within the Fossil Creek Basin as defined by the
City of Fort Collins Drainage Basin Map, and as defined in the Fossil Creek
Drainage Basin Master Drainageway Planning Study.
a. Refer to Figure 1 on Page 3 of the Fossil Creek Drainage Basin Master
Drainageway Planning Study in Appendix III of this report.
PAGE 2
Final Drainage and Erosion Control Report
Project No. 1005-42-94
H. DRAINAGE BASINS AND SUB -BASINS:
A. Major Basin Description: (continued)
2. All historic storm runoff from the site is directed to Skyway Drive directly, or via
the gutter in Constellation Drive and eventually conveyed to South College Avenue
(State Highway 287). There is an existing catch basin in a sump condition
approximately 200 feet north of Skyway Drive which intercepts water from the
surrounding area. Stormwater is then conveyed under South College Avenue and to
the east, eventually reaching Fossil Creek Reservoir.
4. There are no existing irrigation ditches on the site which would require ditch
company approval of this project.
5. The Louden Ditch is located just east of the site. Development of the site will not
affect the Louden Ditch.
B. Sub -basin Description:
1. The site slopes from the southwest corner to the northeast corner. There is
approximately 24 feet of relief across the property.
2. Historically, the site can be divided into 2 sub -basins (Sub -basins 1 & 2). Sub -basin
1 contributes stormwater to the Skyway Drive at the northeast corner. Sub -basin 2
contributes stormwater to Skyway Drive as well. However this basin outfalls east of
the northeast corner into Skyway Drive. For purposes of design the 2 sub -basins
were combined to determine the historic peak flows from the site.
4. Development of the site will channelize runoff by directing runoff from the lots into
the street system and into the detention pond, or directly to Constellation Drive. The
developed site will convey as much of the stormwater as possible to the detention
pond.
5. There is also an offsite Sub -basin (Sub -basin 3) south of the site which contributes
stormwater to Skyway Drive via Constellation Drive. This stormwater will not be
detained in the detention pond. Refer to the Historic Conditions Plan in Appendix
IV. All stormwater runoff from the site and offsite eventually reaches South College
Avenue. From there stormwater is conveyed to Fossil Creek.
III. DRAINAGE DESIGN CRITERIA:
A. Regulations:
1. Design Criteria from the Larimer County Storm Water Management Manual and the
Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual
were considered.
2. Erosion control measures conform to the requirements of the Latimer County
Engineering Department and generally accepted erosion control procedures.
PAGE 3 .
Final Drainage and Erosion Control Report
Project No. 1005-42-94
III. DRAINAGE DESIGN CRITERIA:
B. Development Criteria Reference and Constraints:
1. The site is bounded on the west and north by Constellation Drive and Skyway Drive
respectively. All proposed grading must match the grades of the back of walk or
existing curb and gutter along these streets.
2. The driveway for Foothills Gateway is located east of the property line. All proposed
grading must match the existing grades at the east property line unless a temporary
grading easement is provided to the developer.
C. Hydrological Criteria:
1. The Rainfall -Intensity -Duration curves for Larimer County were used (Fig. 3.3.1-1,
attached in Appendix H for reference), in association with the "Rational Method" for
determining peak flows at various concentration points.
2. The 2 and 100-year storms were analyzed in the design of the stormwater
management infrastructure in accordance with Larimer County Storm -Water
Management criteria. The 10-year storm was also included in the calculations of
peak flows at various concentration points.
3. Detention pond requirements were determined utilizing the "Cumulative Runoff
Method" as presented in the Larimer County Storm -Water Management Manual.
a. The pond was sized to release at historic rates i.e. the developed 100-year storm
should be released at the historic 100-year rate. This was approved with the
Preliminary Plat.
b. Detention volumes for the 2 and 10-year storms were also determined.
D. Hydraulic Criteria:
1. Storm sewer and drainage channel capacities were based on the Mannings Equation.
The Mannings coefficients are as suggested by Larimer County Storm -Water
Management Manual.
2. Orifice and weir equations and coefficients for detention pond outlet control, are as
suggested by Larimer County Stormwater Management Manual.
IV. DRAINAGE FACILITY DESIGN:
A. General Concept:
1. Detention will be provided in the northeast comer of the site according to Larimer
County requirements. This area is defined as Tract A and is designated a Drainage
and Open Space easement on the Final Plat for Aurora Hills Subdivision. Release
rates were based on the peak flows generated for the design storm using historic
conditions, i.e. developed 2-year releases at the historic 2-year peak flow.
PAGE 4
Final Drainage and Erosion Control Report
Project No. 1005-42-94
IV. DRAINAGE FACILITY DESIGN:
.. A. General Concept: (continued)
2. The proposed street grading attempts to convey as much of the site runoff to the
detention pond as possible. Inlets and sidewalk culverts are provided to intercept
runoff and divert it into the pond.
B. Specific Details: - Detention Pond
1. The detention pond has been sized for the 100-year storm.
a. Final calculations indicate that 11,734 cubic feet of storage is required for the
developed 100-year storm, restricting the release to pre -development 100-year
runoff rates.
b. Final grading has provided approximately 27,580 cubic feet of storage volume,
including freeboard.
2. A berm will be constructed along the northern and eastern property lines of Tract A.
a. The top of the berm defining the detention pond area is at elevation of 5046.50
feet.
b. The side slopes on the berm are no greater than 4:1 (H:V).
3. A type 2 outlet structure will be provided within the limits of the berm to restrict
flows to pre -development runoff rates. The outlet structure will be located near the
Northeast corner of Tract A.
a. The outfall release rate utilized for the 2-year storm is 3.57 cfs. An 9" diameter
orifice is provided -to restrict outfall rates to 3.57 cfs for the 2-year storm event.
b. The outfall release rate utilized for the 10-year storm is 6.29, cfs. A 12" diameter
orifice is provided to restrict outfall rates to 6.35 cfs for the 10-year storm event.
c. The outfall release rate utilized for the 100-year storm is 13.18 cfs. A 20' wide
broadcrested weir is provided to restrict outfall rates to 13.18 cfs for the 100-year
storm event and provide the necessary storage volumes. A 6' x 6' box with 6"
walls will create the 20' weir.
d. The top of the detention pond outlet structure will be provided with a trash rack
which will be well secured.
e. An emergency overflow weir will be built into the berm at the northeast corner of
the pond. The weir is sized to pass the developed Q100 in case the structure is
clogged. The invert of the weir will be set at an elevation of 5046.50 feet. The
overflow runoff will be conveyed into Skyway. Drive. Riprap will be provided on
the downstream side of overflow.
PAGE 5
Final Drainage and Erosion Control Report
Project No. 1005-42-94
W. DRAINAGE FACILITY DESIGN:
B. Specific Details: - Detention Pond
4. The conveyance from the detention pond outlet structure consists of the following:
a. An 18" ADS culvert with a flared end section which daylights behind the back of
detached walk on Skyway Drive.
b. A curbed channel from the pipe to the .back of the detached walk and from the
detached walk to the vertical curb.
c. A 2' metal sidewalk culvert at the Skyway Drive detached walk. A detail is
provided.
C. Specific Details: - Swales
L . A triangular grass lined swale (Section A -A) has been provided at the rear of Lots 1-
10 of Block 2 to intercept and convey stormwater to the detention pond. The design
flow for the swale is 133% of the 100-year peak flow (1.33 x Q100) to the pond from
the rear of Lots 1-10 of Block 2 (Sub -basin Ie) to the northeastern corner of Lot 1,
Block 2 (concentration Point E). Refer to pages 8 & 8A in the drainage calculations
located in Appendix I. A twenty (20') foot drainage easement has been provided for
the drainage swale on the Final Plat of Aurora Hills Subdivision. The swale has the
following characteristics:
a. The minimum allowable slope of the grass lined Swale is 2.0%.
b. The depth of the swale is 1.0 foot.
c. The side slopes of the swale are 4:1 (H:V)
d. The Mannings n value for the swale is 0.032.
e. The capacity of the swale, based on the minimum slope of 2.0%, is 16.22 cfs .
f. The Q100 to Concentration Point E (swale runoff entry to detention pond) is 4.42
cfs. 133% of Q100 to Concentration Point E is 5.88 cfs.
1G.r.T
PAGE 6
Final Drainage and Erosion Control Report
Project No. 1005-42-94
IV. DRAINAGE FACILITY DESIGN:
C. Specific Details: - Swales
2. A triangular grass lined swale (Section B-B) has been provided at the rear of Lots 11-
14 of Block 1 to convey stormwater into Skyway Drive. The design flow for the
swale is 133% of the 100-year peak flow (1.33 x Q100) to the pond from the rear of
Lots 1-10 of Block 2 (Minor basin lf) to the northeastern corner of Lot 1, Block 1
(concentration Point F). Refer to pages 9 and 9A in the drainage calculations located
in Appendix I. A twenty (20') foot Drainage Easement has been provided for the
drainage swale on the Final Plat of Aurora Hills Subdivision. The swale has the
following characteristics:
a. The slope of the grass lined swale is 4.0%
b. The depth of the swale is 0.5 foot.
c. The side slopes of the swale are 10:1 (H:V).
d. The Mannings n value for the swale is 0.032.
e. The capacity of the swale, using the 4.0% slope, is 9.18 cfs.
f. The Q100 to Concentration Point F is 2.16 cfs. 133% of Q100 to Concentration
Point F is 2.88 cfs.
D Specific Details: - Storm Sewers
1. Two (2) Type R inlets will be constructed on Polaris Drive at Concentration points B
& C in a continuous grade condition. The inlets are sized to intercept 100% of the
Q100 to Concentration Points B and C respectively.
a. The Q100 to Concentration Point B is 4.00 cfs.
b. The inlet at Concentration Point B is a 15 foot Type R inlet.
c. The Q100 to Concentration Point C is 12.02 cfs.
d. The inlet at Concentration Point C is a 35 foot Type R inlet.
e. A detail has been provided in order to properly locate a standard type R inlet in
association with drive -over curb, gutter and walk.
2. The two (2). inlets are connected by approximately thirty five (35') lineal feet 18"
RCP storm sewer. Mannings 'n value for RCP storm sewer is 0.013.
a. The minimum required slope of the pipe is 0.15%.
b. Refer to the profile in the plans for the actual slope.
PAGE 7
Final Drainage and Erosion Control Report
Project No. 1005-42-94
IV. DRAINAGE FACILITY DESIGN:
D Specific Details: - Storm Sewers
3. Approximately twenty three (23') lineal feet of 24" ADS N-12 conveys the
stormwater from the inlet at concentration point B to the detention pond.
a. The combined Q100 to concentration B is 16.15 cfs.
b. The minimum required slope of the pipe is 0.43%.
c. Refer to the profile in the plans for the actual slope.
4. Two concrete sidewalk culverts will be installed at the intersection of Polaris Drive
and Skyway Drive (Design Point D) to intercept some of the flow in the street. The
culverts are sized to intercept the majority of the 100-year peak flow from Sub -basin
Id. Sub -basin Id consists of the western portion of Aurora Hills which contributes
stormwater to Constellation and Skyway Drives. A certain amount of carry-over flow
is expected at the sidewalk culverts because the sidewalk culverts are only sized to
intercept a portion of the flow from Sub -basin Id.
a. The Q100 to design point D from Sub -basin Id is 8.37 cfs. It was assumed that
75% of the flow (6.27 cfs) was in Skyway Drive and the remaining 25% (2.10
cfs) was in Polaris Drive.
b. An eight (8) foot concrete sidewalk culvert will be constructed at the northeastern
PCR of the sidewalk of the intersection of Polaris Drive and Skyway Drive
(Concentration point D).
c. The capacity of the sidewalk culvert on Skyway Drive is approximately 4.64 cfs.
Approximately 1.64 cfs will by pass the sidewalk culvert. This is considered
negligible.
d. A four (4') foot concrete sidewalk culvert will be installed on the east side of
Polaris Drive near the intersection with Skyway Drive.
e. The capacity of the sidewalk culvert on Polaris Drive is approximately 2.08 cfs.
Approximately 0.01 cfs will by pass the sidewalk culvert. This is considered
negligible.
e. An 15" ADS N-12 pipe will convey the stormwater under the berm into the
detention pond from both culverts.
f. The sidewalk along Skyway Drive is detached, therefore a curbed channel will be
installed as well.
PAGE 8
Final Drainage and Erosion Control Report
Project No. 1005-42-94
V. EROSION CONTROL:
A. General Concept:
1. Temporary erosion control measures will be installed with this project. These
measures include;
a. Silt fence on downstream property lines
b. Hay bales in swales
c. Inlet filters at all inlets
2. The detention pond will act as a sediment pond during construction. This can be
accomplished either by
a. waiting to install the outlet structure until the pond has been permanently
stabilized with sod or grass.
b. installing a gravel filter or hay bale barrier in front of the outlet structure for the
duration of construction. -
3. The silt that has built up in the sediment pond during construction will have to be
removed prior to final grading and soil stabilization.
4. Riprap aprons will be installed at the outfall of the storm sewers into the pond. The
D50 for all riprap is 12".
5. Riprap will be provided with the overflow weir and on the downstream bank from the
overflow weir.
6. Maintenance of erosion control devices will remain the responsibility of the
developer until the project is completed.
PAGE 9
Final Drainage and Erosion Control Report
Project No. 1005-42-94
VI. CONCLUSIONS:
A. Compliance with Standards:
1. All drainage design conforms with the criteria and requirements of the Latimer
County Storm Water Management Manual and Preliminary Plat approvals.
2. Proposed erosion control measures conform with generally accepted erosion control
practices and Latimer County requirements.
B. Drainage Concept:
1. The proposed drainage design for Aurora Hills Subdivision is effective for the
control of storm water runoff. The proposed improvements will reduce overall runoff
quantities.
2. The proposed erosion control devices will be effective in controlling the erosion
created during construction.
VH REFERENCES:
1. Larimer County Storm -Water Management Manual
2. Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual
3. The Fossil Creek Drainage Basin Master Drainageway Planning Study; Simons Li
Associates, 1982.
APPENDIX I
Drainage Calculations
FLOW SUMMARY FOR AURORA HILLS PAGE 1
DATE 12/01/97
DESIGN
CONTRIBUTING
AREA
C2
C10
C100
Tc
Tc
I2
I10
I100
Q2
Q10
Q100
DESIGN
PAGE
POINT
SUB
2,10
100
BASINS)
ac.
min.
min
iph
iph
iph
cfe
cfe
cfe
ttrr r+rrter
rr txtx rxr+rr+:rr:rtt+x+xxrr+rrrrr
trt
xxxrrrr+rrrrrr+rrxrx+rxxt
xrrr+rrx•xx+xrr*+rr+rrt+r
rrrrrrr+rrx+trr
HISTORIC
A
ENTIRE SITE
7.59
0.30
0.30
0.38
27.00
25.00
1.57
2.76
4.63
3.57
6.29
13.18
HISTORIC
3
DEVELOPED
A
ENTIRE SITE
7.59
0.46
0.46
0.57
14.50
14.00
2.18
3.82
6.28
7.61
13.34
27.15
DETAIN
4
B
lb
0.93
0.57
0.57
0.71
12.00
11.50
2.38
4.17
6.82
1.12
1.96
4.00
INLET
5
C
lc
2.87
0.48
0.48
0.60
11.00
10.50
2.46
4.31
7.03
3.37
5.90
12.02
I/P
6
C
lb & lc
3.7
0.50
0.50
0.62
11.00
10.50
2.46
4.31
7.03
4.52
7.92
16.15
PIPE
+**
D
1d
2.03
0.47
0.47
0.59
11.00
10.50
2.46
4.31
7.03
2.34
2.34
8.37
SWC
7
B
1e
1.41
0.40
0.40
0.50
14.00
14.00
2.22
3.89
6.28
1.25
2.19
4.42
SWALB/SWC
e
F
if
0.50
0.40
0.40
0.50
7.00
6.50
2.99
5.16
8.65
0.60
1.03
2.16
SWALE
9
ABBREVIATIONS
I/P =
INLET AND PIPE
SWALE =
SWALE
I =
INLET
SWC =
SIDEWALK CULVERT
NOTE:
*** THE OVERALL FLOW TO DP C FROM SUBBASINS lc &
lb IS
CALCULATED
IN THE
FLOW
SUMMARY
THERE IS NO
SEPARATE DRAINAGE CALCULATION IN APPENDIX I
FOR THIS FLOW
SUMMARY
OF STORM SEWER
INLET
PIPE
DESIGN
Q100
INLET
CAPA-
CAPA-
PIPE
SLOPE
n
C
POINT
SIZE
CITY
CITY
DIAM
cfs
ft
cfe
cfe
ft
ft/ft
B
4.00
15
4.00
16.15
30.22
2.0
0.015
0.012
245.1
C
12.02
35
12.02
12.99
1.5
0.015
0.013
105.0
CONVEYANCE FACTOR = C = (1.486*A*R^2/3)/N
SUMMARY OF
SWALBS
DESIGN
Q100
CAPA-
FLOW
TOP
DEPTH
SLOPE
n SIDE SLOPES
POINT
DESIGN
CITY
WIDTH
LEFT
RIGHT
FLOW
DEPTH
:1
:1
cEe
cfe
cfe
ft
ft
ft
ft/ft
ft/ft
ft/ft
E
4.42
5.88
16.22
0.68
8.00
1.00
0.020
0.032 4.00
4.00
P
2.16
2.88
9.18
0.35
10.00
0.50
0.040
0.032 10.00
10.00
DESIGN FLOW FOR SWALBS = 1.33*Q100
RUNOFF COEPPICIENT SUMMARY FOR DEVELOPED CONDITIONS AT 'AURORA HILLS
SUBBASIN AREA C2 C10 C100
is
0.45
0.23
0.23
0.29
lb
0.83
0.57
0.57
0.71
lc
2.87
0.48
0.48
0.60
id
2.03
0.47
0.47
0.59
le
1:41
0.40
0.40
0.50
ENTIRE SITE
7.59
0.46
0.46
0.57
MINOR BASIN
if
0.50
0.40
0.40
0.50
LAND USE
BREAK DOWN
SUBBASIN
AREA
ASPHALT
GRASS
OPEN
SPR
.CHECK
C
0.90
0.15
0.20
0.40
x:x:rxrrrrrr+rr rrrr
rr rrxrrxxrrxrr
rr+rrrr+rr rr r+♦r rr r+♦rrrr+rr++r+r+x+r+r+rr•+•+err+r
la
0.45
0.00
0.00
0.38
0.07
0.45
lb
0.83
0.35
0.15
0.00
0.33
0.83
'lc
2.87
0.50
0.12
0.00
2.25
2.87
1d
2.03
0.28
0.00
0.00
1.75
2.03
is
1.41
0.00
0.00
0.00
1.41
1.41
TOTALS
7.59
1.13
- 0.27
0.38
5.81
7.59
MINOR BASIN
if
0.50
0.00
0.00
0.00
0.50
0.50
D
S¢� S1N(�LG- �P��1-i AC5I�ENT�AL
0
SHEAR ENGINEERING CORPORATION
RUNOFF COEFFICIENT FOR DEVELOPED CONDITIONS PAGE 2
ENTIRE SITE
PROJECT AURORA HILLS DATE: 12/01/97
PROJ.NO. 1005-42-94 BY: MEO
LOCATION SKYWAY DRIVE FILE: SKYCOEF
RUNOFF
SURFACE COEF.
CHARACTERISTICS AREA RANGE C C*A
(acres)
PAVEMENT ASPHALT OR CONCRETE 1.130 0.70-0.95 0.90 1.017
GRAVEL 0.000 0.25-0.70 0.50 0.000
ROOFS 0.000 0.70-0.95 0.90 0.000
LAWNS (irrigated) SANDY SOIL
FLAT < 2% 0.000 0.05-0.15 0.10 0.000
_ AVERAGE 2 - 71, 0.000 0.15-0.20 0.17 0.000
STEEP > 7% 0.000 0.20-0.30 0.25 0.000
LAWNS(irrigated) HEAVY SOIL
FLAT < 2% 0.270 0.13-0.17 0.15 0.041
AVERAGE 2 - 71 0.000 0.18-0.22 0.20 0.000
STEEP > 7% 0.000 0.25-0.35 0.30 0.000
COMPOSITE AREAS
URBAN
SINGLE FAMILY, 4-6 UNITS/AC. 5.610 0.25-0.5 0.40 2.324
MULTI -FAMILY, > 6 UNITS/AC. 0.000 0.50-0.75 0.60 0.000
RURAL OPEN SPACE 0.380 0.10-0.40 0.20 0.076
TOTAL AREA 7.590 3.457
C2 CS C10 - C100 '
COMPOSITE C VALUE 0.456 0.456 0.456 0.569
USE 0.46 0.46 0.46 0.57
SHEAR ENGINEERING CORPORATION
HISTORIC PAGE' 3
FLAW TO CONCENTRATION POINT A
FROM ENTIRE SITE
PROJECT: AURORA HILLS DATE 12/01/97
FILE: SKYRAT PROJ. NO.1005-42-94
NOTES: BY MEO
AREA (A)= 7.590 ACRES
RUNOFF COEP. (C)
2 YEAR
10 YEAR
100
YEAR
C = 0.30
0.30
0.38
FOR PASTURE WITH LOAM SOIL
AND LIGHT VEGETATION
TIME OF CONCENTRATION (Tc)
OVERLAND TRAVEL TIME (Ti)
LENGTH = 500 FEET
SLOPE 2.88
4
2_ YEAR
10 YEAR
100
YEAR
C = 0.30
0.30
0.38
Ti (min)= 23.59
23.59
21.38
TRAVEL TIME (TO-L/(60•V)
PLOW TYPE
L (ft) = 265 S (4) -
3.00 LAWN
V
(fps) =
1.26
Tt(min)-
3.51
L (ft) _? S (4) -
0.00 ?
V
(fps) -
0
Tt(min)=
0..00
L (ft) _? S (4) -
0.00 ?
V
(fps) =
0
Tt(min)=
0.00
L (ft) _? S (4) -
0.00 ?
V
(fps) -
0
Tt(min)=
0.00
L (ft) _? S (4) =
0.00 ?
V
(fps) -
0
Tt(min)=
0.00
L (ft) _? S (4) =
0.00 ?
V
(fps) =
0
Tt(min)=
0.00
L (ft) _? S (4) =
0.00 ?
V
(fps) -
0
Tt(min)=
0.00
NOTE: ALL VELOCITIES TAKEN FROM FIGURE 3-2
TOTAL TRAVEL
TIME
(min) =
3.51
Tc =Ti+TOTAL TRAVEL TIME
2 YEAR
10 YEAR
100
YEAR
Tc (min)= 27.10
27.10
24.89
USE Tc 27
27
25
INTENSITY (I) (iph)
2 YEAR
10 YEAR
100
YEAR
I = 1.57
2.76
4.63
NOTE: INTENSITIES TAKEN
FROM FIGURE
3-1
RUNOFF (Q= CIA) (cfs)
2 YEAR
10 YEAR
100
YEAR
Q = 3.57
6.29
13.18
CONCLUDE:USE THESE FLAWS AS MAXIMUM RELEASE RATES FOR SIZING DETENTION POND
PROJECT: AURORA HILLS
PILE: SKYRAT
NOTES:
AREA (A)= 7.590 ACRES
SHEAR ENGINEERING CORPORATION
DEVELOPED
PLOW TO CONCENTRATION POINT A
FROM ENTIRE SITE
DATE 12/01/97
PROJ. NO.3005-42-94
BY MEO
RUNOFF COED. (C)
2 YEAR 10 YEAR 100 YEAR
C = 0.46 0.46 0.57
SHE BASIN SUMMARY ON DRAINAGE AND EROSION CONTROL PLAN
TIME OF CONCENTRATION (TO
OVERLAND TRAVEL TIME (Ti)
LENGTH = 45 FEET SLOPE = 10.004
2 YEAR 10 YEAR 100 YEAR
C = 0.20 0.20 0.25
Ti (min)= 5.28 5.28 4.99
TRAVEL TIME (It) =L/(60*V) PLOW TYPE
L (ft) = 120 s (}) = 4.00 LAWN
L (ft) = 150 S (}) = 0.50 GUTTER
L (ft) = 36 S (4) = 1.00 GUTTER
L (ft) = 360 S (}) = 2.00 GUTTER
L (ft) = 35 S (}) = 4.00 GUTTER
L (ft) _ 80 S (}) = 1.00 PIPE
L (ft) _ -130 S (}) = 1.00 LAWN
NOTE: ALL VELOCITIES TAKEN FROM FIGURE 3-2
LENGTH = 956 (L/180)+10 = 15.31 >
Tc -Ti+TOTAL TRAVELTIME
2 YEAR 10 YEAR 100 YEAR
Tc (min)= 14.41 14.41 14.12
USE Tc = 14.5 14.5 14
INTENSITY (I) (iph)
2 YEAR 10 YEAR 100 YEAR
I = 2.18 3.82 6.28
NOTE: INTENSITIES TAKEN FROM FIGURE 3-1
RUNOFF (Q= CIA) (cfs)
2 YEAR 10 YEAR 100 YEAR
Q = 7.61 13.34 27.15
VERSUS
Qhist. = 3.57 6.29 13.18
CONCLUDE:DETAIN AND RELEASE AT HISTORIC RATES
PAGE 4
V (fpe) =
1.47
It(min)=
1.36
V (fps) -
1.50
Tt(min)=
1.67
V (fps) -
2.00
Tt(min)=
0.30
V (fps) =
2.83
Tt(min)-
2.12
V (fps) _
4.00
Tt(min)-
0.15
V (fps) =
3.00
Tt(min)-
0.44
V (fps) =
0.70
Tt(min)=
3.10
TOTAL TRAVEL
TIME
(min) =
9.13
14.12 CHOOSE LESSER
i
PROTECT: AURORA HILLS
FILE: SKYRAT
NOTES:
AREA (A)= 0.830 ACRES
y v
SHEAR ENGINEERING CORPORATION
FLOW TO CONCENTRATION POINT B
SUBBASIN 1b
DATE 04/03/98
PROJ. NO.1005-42-94
BY HBO
PAGE
5
RUNOFF COEF. (C)
2 YEAR
10 YEAR
100
YEAR
C = 0.57
0.57
0.71
SHE BASIN SUMMARY ON DRAINAGE AND EROSION CONTROL PLAN
TIME OF CONCENTRATION (TO
OVERLAND TRAVEL TIME (Ti)
LENGTH = 60 FEET
SLOPE
= 4.00 t
,
2 YEAR
10 YEAR
100
YEAR
C 0.20
0.20
0.25
Ti (min)= 8.25
8.25
7.79
TRAVEL TIME (Tt)-L/(60*V)
FLOW TYPE
L (ft) - 120 S (t) =
1.50
GUTTER
V
(fps)
2.36
Tt(min)=
0.85
L (ft) = 37 S (t) =
4.50
GUTTER
V
(fps),=
4.18
Tt(min)-
0.15 ,
L (ft) - 158 S (t) =
1.50
GUTTER
V
(fps) =
2.36
Tt(min)-
1.12.
L (ft) = 203 S (t) =
2.00
GUTTER
V
(fps)
2.83
Tt(min)-
1.20
L (£t) 65 S (t) =
4.00
GUTTER
V
(fps) =
4.00
Tt(min)=
0.27
L (ft) -NONE S (t) =
0.00
NONE
V
(fps) -
0.00
.Tt(min)=
0.00
L (ft) =NONE S (t) =
0.00
NONE
V
(fps) -
0.00
Tt(min)=
0.00
NOTE: ALL VELOCITIES TAKEN FROM FIGURE 3-2
TOTAL TRAVEL
TIME
(min) =
3.58
LENGTH 643 (L/180)+10
13.57 >
11.37 CHOOSE LESSER
Tc -Ti+TOTAL TRAVEL TIME
2 YEAR
10 YEAR
100
YEAR
Tc (min)- 11.83
11.83
11.37
-
USE Tc = 12
12
11.5
INTENSITY (I) (iph)
2 YEAR
10 YEAR
100
YEAR
I = 2.38
4.17
6.82
NOTE: INTENSITIES TAKEN
FROM FIGURE 3-1
RUNOFF (Q= CIA) (cfe)
2 YEAR 10 YEAR 200 YEAR
Q = 1.12 1.96 4.00 SIZE INLET FOR Q100
Qtotal = 4.52 7.92 16.25 TOTAL FLOW TO INLET FOR PIPE SIZING
CONCLUDE:Sx - 0.0200 ft/ft FLOW DEPTH ABOVE LIP (D) = 0.26 ft
SEE HAESTAD TABLE OF CAPACITY VERSUS DEPTH FOR LOCAL STBET FOR DEPTH
T = D/Sx - 8 ft n = 0.016
dW = Sx(T-2) 0.120 S = 0.0400 ft/ft
FROM FIGURE 5-5 25 FOOT INLET REQUIRED FOR 100% INTERCEPTION
INSTALL 15 FOOT INLET Qi/Q - 80.00% Qi/Q FROM FIG 5-6 58.009,
TOTAL Qi/Q = 138.00% OK Qi = 4.00 cfe
INSTALL 30 LF OF 24 • ADS 0 0.0152 ft/ft n - 0.022
CONVEYANCE FACTOR = 245.08 PIPE CAPACITY - 30.22 cfe OK
PROJECT: AURORA HILLS
FILE: SKYRAT
NOTES:
AREA (A)= 2.87 ACRES
SHEAR ENGINEERING CORPORATION
PAGE 6
FLOW TO CONCENTRATION POINT C
SUBBASIN lc
DATE 04/03/98
PROJ. NO.1005-42-94
BY HBO
RUNOFF COSP. (C)
2 YEAR 10 YEAR 100 YEAR
C = 0.48 0.48 0.60
SEE BASIN SUMMARY ON DRAINAGE AND EROSION CONTROL PLAN
TIME OF CONCENTRATION (Tc)
OVERLAND TRAVEL TIME (Ti)
LENGTH 45 FEET
SLOPE = 10.00 !
2 YEAR
10 YEAR
100 YEAR_
C = 0.20
0.20
0.25
Ti (min)- 5.28
5.28
4.99
TRAVEL TIME (Tt)-L/(60*V)
FLOW TYPE
L (ft) - 120 S (4) =
4.00 LAWN
V (fps) = 1.47
Tt(min)=
1.36
L (ft) - 150 S (t) =
0.50 GUTTER
V (fps) = 1.50
Tt(min)=
1.67
L (ft) = 36 S (t) =
1.00 GUTTER
V (fps) = 2.00
Tt(min)-
0.30
L (ft) 360 S (4) =
2.00 GUTTER
V (fps) - 2.83
Tt(min)=
2.12
L (ft) - 35 S (4) -
4.00 GUTTER
V (fps) = 4.00
Tt(min)=
0.15
L (ft) = 0 S (i) -
0 NONE
V (fps) - 0.00
Tt(min)=
0.00
L (ft) = 0 S (t) =
0 NONE
V (fps) _?
Tt(min)-
0.00
NOTE: ALL VELOCITIES TAKEN FROM FIGURE 3-2
TOTAL TRAVEL TIME
(min) =
5.59
LENGTH = 746 (L/180)+10 - 14.14
>
10.58 CHOOSE LESSER
Tc -Ti+TOTAL TRAVEL TIME
2 YEAR
10 YEAR
100 YEAR
Tc (min). 10.97 -
10.87
10.58
USE Tc = 11
11
10.5
INTENSITY (I) (iph)
2 YEAR
10 YEAR
100 YEAR
I = 2.46
4.31
7.03
NOTE: INTENSITIES TAKEN
FROM FIGURE
3-1
RUNOFF (Q= CIA) (cfe)
2 YEAR
10 YEAR
100 YEAR
Q = 3.37
5.90
12.02
SIZE INLET AND PIPE FOR Q100
CONCLUDE:Sx = 0.0200 ft/ft FLOW DEPTH ABOVE LIP (D) - 0.26 ft
SHE HARSTAD TABLE OF CAPACITY VERSUS DEPTH FOR LOCAL STEET FOR DEPTH
T - D/Sx = 13 ft n = 0.016
dW - SX(T-2) - 0.220 S - 0.0400 ft/ft
FROM FIGURE 5-5 50 FOOT INLET REQUIRED FOR 100% INTERCEPTION
INSTALL 35 FOOT INLET Qi/Q 85.00% Qi/Q FROM FIG 5-6 =
TOTAL Qi/Q 103.004 OK Qi = 12.02 cfe
INSTALL 30 LF OF 18 " RCP Q 0.0153 ft/ft n = 0.013
CONVEYANCE FACTOR - 105.04 PIPE CAPACITY - 12.99 cfe OK
4b
SHEAR ENGINEERING CORPORATION
PAGE
FLOW TO CONCENTRATION POINT D
SUBBASIN ld
PROJECT: AURORA HILLS DATE 12/01/97
FILE: SKYRAT PROJ. NO.1005-42-94
NOTES: BY MEO
AREA (A)= 2.030 ACRES
RUNOFF COEF. (C)
7
2 YEAR
10
YEAR
100
YEAR
C =
0.47
0.47
0.59
SEE BASIN
SUMMARY
ON DRAINAGE AND EROSION CONTROL PLAN
TIME OF CONCENTRATION (Tc)
,
OVERLAND TRAVEL TIME (Ti)
LENGTH =
45
FEET SLOPE
= 10.00
2 YEAR
10
YEAR
100
YEAR
C =
0.20
0.20
0.25
Ti (min)=
5.28
5.28
4.99
TRAVEL TIME (Tt)
-L/(60MV)
FLOW TYPE
L (ft) =
120
S (i)
4.00
GRASS
V
(fps) =
0.00
Tt(min)-
0.00
L (ft) =
100
S (k) =
2.00
GUTTER
V
(fps) =
2.83
Tt(min)=
0.59
L (ft) =
240
S (i)
0.60
GUTTER
V
(fps) =
1.61
Tt(min)=
2.48
L (ft) =
170
S (t) =
5.00
GUTTER
V
(fps) _
.4.45
Tt(min)-
0.64
L (ft) =
280
S (i) =
1.70
GUTTER
V
(fps) =
2.36
Tt(min)=
1.98
L (ft) =
0
S (t) =
0.00
NONE
V
(fps) =
0.00
Tt(min)=
0.00
L (ft) =
0
S (i) =
0.00
NONE
V
(fps) =
0.00
Tt(min)=
0.00
NOTE: ALL VELOCITIES TAKEN
FROM
FIGURE 3-2
TOTAL TRAVEL
TIME
(min) =
5.69
LENGTH =
955
(L/180)+10 =
15.31 >
10.67 CHOOSE LESSER
Tc =Ti+TOTAL TRAVEL TIME
2 YEAR 10 YEAR 100 YEAR
Tc (min) = 10.97 10.97 10.67
USE Tc = 11 11 10.5
INTENSITY (I) (iph) ..
2 YEAR 10 YEAR 100 YEAR
I = 2.46 4.31 7.03
NOTE: INTENSITIES TAKEN FROM FIGURE 3-1
RUNOFF (Q= CIA) (cfe)
2 YEAR 10 YEAR 100 YEAR
Q = 2.34 4.10 8.37
CONCLUDE:INSTALL 2 CONCRETE SIDEWALK CULVERT TO CONVEY WATER INTO POND
CULVERTS TO BE LOCATED AT PCRS ON SKYWAY DRIVE AND POLARIS DRIVE
SIDEWALK CULVERT ON SKYWAY DRIVE IS TO BE 10.00 FEET LONG
SIDEWALK CULVERT ON POLARIS DRIVE IS TO BE 4.00 FEET LONG.
PROJECT: AURORA HILLS
FILE: SKYRAT
NOTES:
AREA (A)= 1.410 ACRES
SHEAR ENGINEERING CORPORATION
PAGE B
FLOW TO CONCENTRATION POINT B
SUBBASIN is
DATE 12/01/97
PROJ. NO.1005-42-94
BY HBO
RUNOFF COEF. (C)
2 YEAR 10 YEAR 100 YEAR
C = 0.40 0.40 0.50
SEE BASIN SUMMARY ON DRAINAGE AND EROSION CONTROL PLAN
TIME OF CONCENTRATION (TO
OVERLAND TRAVEL TIME (Ti)
LENGTH = 100 FEET SLOPE = 4.00 i
2 YEAR 10 YEAR 100 YEAR
C = 0.20 0.20 0.25
Ti (min)= 10.65 10.65 10.06
TRAVEL TIME (TO-L/(60+V) FLOW TYPE
L (ft) = 600 S M - 2.00 SWALE
L (ft) = 0 S (14) - 0.00 NONE
L (ft) = 0 S (i) = 0.00 NONE
L (ft) = 0 S (i) v 0.00 NONE
L (ft) - 0 S (t) = 0.00 NONE
L (ft) = 0 S 00 - 0.00 NONE
L (ft) = 0 S (i) = 0.00 NONE
NOTE: ALL VELOCITIES TAKEN FROM FIGURE 3-2
LENGTH = 700 (L/180)+10 = 13.89 <
Tc =Ti+TOTAL TRAVEL TIME
2 YEAR 10 YEAR 100 YEAR
Tc (min)= 13.89 13.89 13.89
USE Tc - 14 14 14
INTENSITY (1) (iph)
2 YEAR 10 YEAR 100 YEAR
I = 2.22 3.89 6.28
NOTE: INTENSITIES TAKEN FROM FIGURE 3-1
RUNOFF (Q= CIA) (cfs)
2 YEAR 10 YEAR 100 YEAR
Q = 1.25 2.19 4.42
V (fps) =
2.16
Tt(min)=
V (fps) =
0.00
Tt(min)=
V (fps) =
0.00
Tt(min)=
V (fps) =
0.00
Tt(min)=
V (fps) =
0.00
Tt(min)v
V (fps) =
0.00
Tt(min)=
V (fps) =
0.00
Tt(min)=
TOTAL TRAVEL
TIME
(min) v
14.69 CHOOSE LESSER
CONCLUDE:CONSTRUCI A TRIANGULAR GRASSED SWALE TO HANDLE DESIGN FLOW
DESIGN FLOW -1.33 + Q100 = 5.88 CPS DESIGN FLOW FOR CHANNEL
SEE SWALE DESIGN ON PAGE 8 A
4.63
0.00
0.00
0.00
0.00
0.00
0.00
4.63
SHEAR ENGINEBRING CORPORATION
PAGE 8 A
CHANNEL CAPACITY
PROTECT NAME: AURORA HILLS DATE: 12/01/97
PROJECT NO. : 1005-42-94 BY : HBO
SWALE DESCRIPTION:SWALB AT REAR OF LOTS 1-10 ELK 2
SECTION A -A
FILE: SKYRAT
CAPACITY OF TRIANGULAR OR TRAPEZOIDAL CHANNEL
CHANNEL CONFIGURATION: TRIANGULAR DESIGN PLOW (cfe) 5.88
CHANNEL LINING: GRASS
Da Db Dc Sc n W I
(ft) (ft) (ft) (4) (ft) (ft)
--- ---- ---- ---- ----- ---- ----
4.00 4.00 1.00 2.00 0.032 0.00 0.25
0.25 - LEFT BANK SLOPE= 4.00 :1 (H:V)
0.25 = RIGHT BANK SLOPE= 4.00 :1 (H:V)
DEPTH WIDTH AREA PERIM R 2/3 Sc 1/2 Q V
(ft) (ft) (s.f.) (ft) (A/P) (cfe) (ft/sec)
-------------------------------------------------------
1.00 8.00 4.00 8.25 0.62 0.14 16.22 4.05
0.75 6.00 2.25 6.18 0.51 0.14 7.53 3.35
0.50 4.00 1.00 4.12 0.39 0.14 2.55 2.65
0.25 2.00 0.25 2.06 0.24 0.14 0.40 1.61
0.00 0.00 0.00 0.00 0.00 0.14 0.00 0.00
0.68 5.44 1.85 5.61 0.48 0.14 5.80 3.14 ***
r rrrrrrrr r:r:rrrrrrrrrrrrr•rrrr•rrvrrrx vvvxrervxvxvr•rrrvvxvxvxvrvr vvxvx
DEPTH WIDTH AREA PERIM R 2/3 Sc 1/2 Q V
NOTE: 2.00% IS THE MINIMUM ALLOWABLE SLOPE FOR GRASS CHANNELS
*** = APPROXIMATE FLOW DEPTH FOR DESIGN FLOW ,
s
SHEAR ENGINEERING CORPORATION
PAGE 9
FLOW TO CONCENTRATION.POINT P
MINOR BASIN if
PROJECT: AURORA HILLS DATE 12/01/97
PILE: SKYRAT PROJ. NO.1005-42-94
NOTES: BY MHO
AREA (A)= 0.500 ACRES
RUNOFF COEF. (C)
2 YEAR
10 YEAR 100
YEAR
C =
0.40
0.40
0.50
SEE BASIN
SUMMARY ON DRAINAGE AND EROSION CONTROL
PLAN
TIME OF CONCENTRATION (TO
OVERLAND TRAVEL TIME (Ti)
LENGTH =
25 FEET
SLOPE = 4.00 ►
2 YEAR
10 YEAR 100
YEAR
C =
0.20
0.20
0.25
Ti (min)=
5.33
5.33
5.03
TRAVEL TIME (Tt)=L/(60*V)
FLOW TYPE
L (ft) =
280 S M =
4.00 SWALE
V
(fps) =
3.00
Tt(min)-
1.56
L (ft) _
0 S (i) =
0 NONE
V
(fps) =
0.00
Tt(min)=
0.00
L (ft) =
0 S (k) =
0 NONE
V
(fps) =
0.00
Tt(min)=
0.00
L (ft) =
0 S (t)
= 0 NONE
V
(fps) =
0.00
Tt(min)=
0.00
L (ft) =
0 S (\)
= 0 NONE
V
(fps) =
0.00
Tt(min)=
0.00
L (ft) =
0 S (t)
= 0 NONE
V
(fps) =
0.00
Tt(min)=
0.00
L (ft) =
0 S 00
= 0 NONE
V
(fps) =
0.00
Tt(min)=
0.00
NOTE:
ALL VELOCITIES TAKEN FROM FIGURE 3-2
TOTAL TRAVEL
TIME
(min) =
1.56
LENGTH =
305 (L/180)+10 - 11.69 >
6.59 CHOOSE LESSER
Tc =Ti+TOTAL TRAVEL TIME
2 YEAR
10 YEAR 100
YEAR
Tc (min)-
6.88
6.88
6.59
USE Tc =
7
7
6.5
INTENSITY
(I) (iph)
2 YEAR
10 YEAR 100
YEAR
I =
2.99
5.16
8.65
NOTE:
INTENSITIES TAKEN
FROM FIGURE 3-1
RUNOFF (Q= CIA) (cfs)
2 YEAR
10 YEAR 100
YEAR
Q. =
0.60
1.03
2.16
CONCLUDE:CONSTRUCI
A TRIANGULAR GRASSED SWALE TO
HANDLE
Q100
1.33 * 0100 =
2.88 CPS DESIGN FLOW FOR CHANNEL
INSTALL 2.00
FOOT METAL SIDEWALK CULVERT
AT OUTFALL
OF SWALE
HEIGHT OF OPENING=
0.50 FT
AREA OF CHASE =
1.00 SF PERIMETER =
5.00 FT
HYDRAULIC RADIUS
= 0.2000 n - 0.0160
SLOPE - 0.0100
ft/ft
Qcap = (1.486*A*R"2/3*5^0.5)/n
3.18
CONCLUDE:SIDEWALK CULVERT IS ADEQUATE. SHE SWALE DESIGN ON PAGE 9 A
SHEAR ENGINEERING CORPORATION
PAGE 9 A
CHANNEL CAPACITY
PROJECT NAME: AURORA HILLS DATE: 12/01/97 .
PROJECT NO. 1005-42-94 BY : MEO
SWALE DESCRIPTION:SWALE AT REAR OF LOTS 11-14 ELK 1
SECTION B-B
FILE: SKYRAT
CAPACITY OF TRIANGULAR OR TRAPEZOIDAL CHANNEL
CHANNEL CONFIGURATION: TRIANGULAR DESIGN FLOW (cfe) 2.88
CHANNEL LINING: GRASS
Da Db Dc Sc n W I
(ft) (ft) (ft) (4) (ft) (ft)
---- ---- ---- ---- ----- ---- ---- _
5.00 5.00 0.50 4.00 0.032 0.00 0.10
0.10 - LEFT BANK SLOPE= 10.00 :1 (H:V)
0.10 = RIGHT BANK SLOPE= 10.00 :1 (H:V)
DEPTH WIDTH AREA PBRIM R 2/3 Sc 1/2 Q V
(ft) (ft) (s.f.) (ft) (A/P) (cfe) (ft/eec)
--------------------- ------- ""'--- "'"--- ------- -------
0.50 10.00 2.50 10.05 0.40 0.20 9.18 3.67
0.40 8.00 1.60 8.04 0.34 0.20 5.06 3.17
0:30 6.00 0.90 6.03 0.28 0.20 2.35 2.61
0.20 4.00 0.40 4.02 0.21 0.20 0.80 1.99
0.10 2.00 0.10 2.01 0.14 0.20 0.13 1.26
0.35 7.00 1.22 7.03 0.31 0.20 3.55 2.90 *+*
: rrrrrrrrrrrr•rrrrrrrrrrrrrrrrrrrrrrrrrririiiiirrrirrrrrrrrrrrrrrrrrrrrr
DEPTH WIDTH AREA PERIM R 2/3 Sc '1/2 Q V
NOTE: 2.00i IS THE MINIMUM ALLOWABLE SLOPE FOR GRASS CHANNELS
rrr = APPROXIMATE FLOW DEPTH FOR DESIGN FLOW
SHEAR ENGINEERING CORPORATION
PAGE 10
DETENTION VOLUME REQUIRED FOR
AURORA HILLS 100 YEAR STORM
WITH 100 YEAR RELEASE RATE
PROJECT: AURORA HILLS DATE: 12/02/97
PROJ.NO. 1005-42-94
PILE: SKYCUHP BY MBO
CUMULATIVE RUNOFF METHOD
FOR
SIZING DETENTION PONDS
DESIGN STORM: 100 YEAR RUNOFF COEFFICIENT 0.57
RELEASE RATE: 13.18 CPS AREA: 7.59 ACRES
INITIAL TIME: 5 MINUTES
TIME INCREMENT: 5 MINUTES
INFLOW INFLOW RELEASE STORAGE STORAGE
TIME TIME INTENSITY RATE VOLUME VOLUME VOLUME VOLUME
min sec iph cfs - cf cE cf ac-£t
+++rrrrrrrr rr+rrrrrrrrrrrrrr:rrrrrrrr•+rrr•+r+rrrrrrrrrrrrrrrrrrrr r:+r+r
5 300 9.30 40.23 12070.4 3954.0 8116.4 0.19
10 600 7.14 30.89 18533.9 7908.0 10625.9 0.24
15 900 6.06 26.22 23595.6 11862.0 11733.6 0.27
20 1200 5.21 22.54 27048.0 15816.0 11232.0 0.26
25 1500 4.63 20.03 30046.2 19770.0 10276.2 0.24
30 1800 4.20 18.17 32706.8 23724.0 8982.8 0.21
35 2100 3.81 16.48 34614.7 27678.0 6936.7 0.16
40 2400 3.60 15.57 37379.2 31632.0 5747.2 0.13
45 2700 3.28 14.19 38313.7 35586.0 2727.7 0.06
r+rr+rr++rrrrrrrrrrrrr rrr rrrr:rr:rrrrrrrxxr+rxrrr+rrrrrrrrrrrrrrrrrrrrxr
DETENTION VOLUME REQUIRED = 11734 cf
DETENTION VOLUME REQUIRED = 0.27 ac-ft
e
;t
SHEAR ENGINEERING
CORPORATION
PAGE
DETENTION VOLUME REQUIRED FOR
AURORA HILLS
10
YEAR STORM
WITH
10
YEAR RELEASE RATE
PROTECT: AURORA HILLS
DATE:
12/02/97
PROJ.NO. 1005-42-94
FILE: SKYPOND
BY
MEO
CUMULATIVE RUNOFF
METHOD
FOR
SIZING DETENTION PONDS
DESIGN STORM:
10
YEAR
RUNOFF COEFFICIENT 0.46
RELEASE RATE:
6.29
CPS
AREA:
7.50 ACRES
INITIAL TIME:
5
MINUTES
TIME INCREMENT:
5
MINUTES
INFLOW
INFLOW
RELEASE
STORAGE STORAGE
TIME TIME INTENSITY RATE
VOLUME
VOLUME
VOLUME VOLUME
min sec
iph
cfs
cf
cf
cf
ac-ft
+:+r+++++++e•1++++•rfffr++r+++rxfrwxwrxr+wrrrrff+r•rffrff
wxf xrx rxrrrrrxe
5 300
5.64
19.46
5837.4
1887.0
3950.4
0.09
10 600
4.45
15.35
9211.5
3774.0
5437.5
0.12
15 900
3.75
12.94
11643.8
5661.0
5982.8
0.14
20 1200
3.25
11.21
13455.0
7548.0
5907.0
0.14
25 1500
2.87
9.90
14852.3
9435.0
5417.3
0.12
30 1800
2.60
8.97
16146.0
11322.0
4824.0
0.11
35 2100
2.38
8.21
17243.1
13209.0
4034.1
0.09
40 2400
2.19
7.56
18133.2
15096.0
3037.2
0.07
45 2700
2.02
6.97
18816.3
16983.0
1833.3
0.04
50 3000 1.87
f twtwtwtwwtwwfffwtttwtwtf wfwwtf
6.45 19354.5 18870.0 484.5
if tf tft+r+111111r+fffftxfxrxrt r'k \\rf\\r\\
0.01
DETENTION VOLUME REQUIRED
- 5983
cf
DETENTION VOLUME REQUIRED
- 0.14
ac-ft
l0a
SHEAR ENGINEERING CORPORATION
PAGE lob
DETENTION VOLUME REQUIRED FOR
AURORA HILLS 2 YEAR STORM
WITH 2 YEAR RELEASE RATE
PROTECT: AURORA HILLS DATE: 12/02/97
PROJ.NO. 1005-42-94
PILE: SKYPOND BY MEO
CUMULATIVE RUNOFF METHOD
FOR
SIZING DETENTION PONDS
DESIGN STORM:
2 YEAR RUNOFF COEFFICIENT 0.46
RELEASE RATE:
3.57 CPS AREA: 7.50 ACRES
INITIAL TIME:
5 MINUTES
TIME INCREMENT:
5 MINUTES
INFLOW INFLOW RELEASE STORAGE STORAGE
TIME TIME INTENSITY RATE VOLUME VOLUME VOLUME VOLUME
min sec iph cfa cf cf cf ac-ft
+rr+rrr+r+rrrr+r+rrr+rr+:rrre:rrrrrrrrrrxrrrrrr rrr+rrrr+r+:r++rrxrrrrrrr
5 300 3.29 11.35 3405.2 1071.0 2334.2 0.05,
10 600 2.54 8.76 5257.8 2142.0 3115.8 0.07
15 900 2.14 7.38 6644.7 3213.0 3431.7 0.08
20 1200 1.85 6.38 7659.0 4284.0 3375.0 0.08
25 1500 1.63 5.62 8435.3 5355.0 3080.3 0.07
30 1800 1.47 5.07 9128.7 6426.0 2702.7 0.06
35 2100 1.32 4.55 9563.4 7497.0 2066.4 0.05
40 2400 1.20 4.14 9936.0 8568.0 1368.0 0.03
45 2700 1.12 3.86 10432.8 9639.0 793.8 0.02
50 3000 1.04 3.59 10764.0 10710.0 54.0 0.00
•rrrrxrrr♦rrrrr+rrr+♦+r+r+rr:r++:r+rrrr+r+rrrrrxrxrrrrrrrrrrrrrr+rr+r+rr
DETENTION VOLUME REQUIRED - 3432 cf
DETENTION VOLUME REQUIRED = 0.08 ac-ft
2
SHEAR ENGINEERING CORPORATION
PAGE
AVERAGE END AREA METHOD
FOR DETENTION BASIN
VOLUMES
PROJECT :AURORA HILLS
DATE:
04/28/98
PROD. NO:1005-42-94
BY
MHO
LOCATION:Skyway Drive
FILE:
SKYPOND
Larimer County
INVERT 5042.64
FEET
FIRST EVEN CONTOUR
5043 FEET
INCREMENT 1
FOOT
TOP BLEV
5046.5 FEET
SCALE:
1.
50 FEET
of rrffrr rf rrerrr rrof rrer
rer rrfrr
rr rr re»
rr+r+r+r
»+r++++
STAGE ELEV AREA
VOLUME
CUM.
CUM.
CUM.
(A2)
(V1)
VOLUME
VOLUME
VOLUME
ft ft eq ft
r rrrffrr rrfrrrrf re rrr rrr
cf
rr rr re rr
cf
rrr rr rrr
cy
r+r++r+r
ac-ft
rrr r+r:r
0.00 5042.64 0
0
0
0
0.00
0.36 5043 214
39
39
1
0.00
1.36 5044 7307
3761
3799
141
0.09
2.36 5045 9161
8234
12033
446
0.28
3.36 5046 10761
9961
21994
815
0.50
3.86 5046.5 11582
5586
27580
1021
0.63
r rrr:rrr rrre:ere rr:rrrrr
rrerrrrr
rrr+r++r
rrrrr+++
frrrrf rf
STAGE BLBV AREA
VOLUME
CUM.
CUM.
CUM.
(A2)
(V1)
VOLUME
VOLUME
VOLUME
ft ft eq ft
cf
cf
cy
ac-ft
100 YEAR STORM
REQUIRED VOLUME = 11734
CP
0.27
AC -PT
REQUIRED W.S. ELEV. =
5044.96
FEET
FREEBOARD PROVIDED = 1.54 FEET
rr♦rrrrrrrr++ryrrfrrrrrr++rr rf rrr+f ♦f rffff rf♦
10 YEAR STORM
REQUIRED VOLUME = 5991.00
CP
0.14
AC -PT
REQUIRED W.S. ELEV. =
5044.27
PERT
FREEBOARD PROVIDED = 2.23
+rrr+rr+rrrr+rrfr+r+r:rfrrf rrrr♦rf rrffffffrff
PERT
-
2 YEAR STORM
REQUIRED VOLUME '= 3585
CP
0.08
AC -FT
REQUIRED W.S. BLEV. =
5043.94
PBET
FREEBOARD PROVIDED =
2.56
FEET
CONCLUDE:POND HAS ADEQUATE
VOLUME FOR ALL DESIGN STORMS
11
SHEAR ENGINEERING CORPORATION
PAGE 12
OUTLET STRUCTURE FOR AURORA HILLS SUBDIVISION
PROTECT: AURORA HILLS SUBDIVISION DATE: 04/28/98
PROTECT NO 1005-42-95 BY HBO
PROTECT LOCATION :SKYWAY DRIVE FILE NAME: SKYPOND
LARIMER COUNTY
INPUT FOR OUTLET STRUCTURE
STRUCTURE TYPE:
TYPE 2
WEIR TYPE
BROADCRESTED
DETERMINE
ORIFICE SIZE
LOWER ORIFICE DIAM. (ft) =
0.75
WEIR LENGTH (ft) =
16.00 5X5 BOX
FOR MINOR
STORM
LOWER ORIFICE INV. (ft) -
5042.64
WEIR INVERT (ft) -
5045.10
Q= CA(2gH)"0.5
LOWER ORIFICE COEF. (Cl) =
0.65
WEIR COEF. (Cw)
= 2.60
A = Q/(C(2gH)"0.5
UPPER ORIFICE DIAM.(ft) =
1.00
TOP OF BERM (ft)
- 5047.00
H (ft) =
1.30
UPPER ORIFICE INV. (ft) =
5043.75
INIT. DELTA (ft)
= 0.36
C
0.65
UPPER ORIFICE CORP. (Cu) =
0.65
DELTA HEAD (ft)
= 1.00
Q (cfe)=
3.57
2 YR. RELEASE RATE (cfe) =
3.57
2 YR WSEL REQUIRED (ft) - 5043.94
A =
0.60
10 YR RELEASE RATE (cfe) =
6.29
10 YR WSEL REQUIRED (ft) - 5044.27
R (ft) =
0.437
100 YR RELEASE RATE (cfe)=
13.18
100 YR WSEL REQUIRED (ft)= 5044.96
D (ft) _
0.874
OUTLET PIPE DIAM. (ft) =
1.50
OVER FLAW
YES
PIPE SLOPE (i) =
1.35
WEIR TYPE
TOP OF BERM
MANNINGS n =
0.012
WEIR LENGTH (ft)
- 20.00
Top of Lower Orifice(ft) =
5043.39
WEIR INVERT (ft)
= 5046.50
Top of Upper Orifice(ft) =
5044.75
WEIR COEF. (Cwo)
= 2.60
rrxrrrrr rrrrxxrr rrrrrxxr
*OUTPUT*
xxrxirxr rrrxrrxr
rrrrrx** rrrxrxrr
PIPE AREA (SF) - 1.77
WETTED PERIMETER
- 4.71 PEET
HYD. RAD (FT) = 0.375
FEET
R^2/3 = 0.5199
OUTLET PIPE CAPACITY
13.22
CPS
LOWER ORIFICE AREA (A) =
0.4418
SQUARE FEET
UPPER ORIFICE AREA (A) =
0.7854
SQUARE PEET
rrxxrrxrxxxrx:rx xxxxxxxxrxrrxxxxrxrxrexrrrerr♦re rrrrrrrrrr•xxrrx
rxrxr xrrrrrrxrxxrrxxr
rrrxr
REQ'D
ACTUAL
NOTE: ELEV
Q
ELEV
Q
ACTUAL FT
CPS
VERSUS
REQUIRED -
PT
CPS
2-YEAR WSEL 5044.304
3.57
2-YEAR WSEL
5043.94
2.22
10-YEAR WSEL 5044.848
6.29
10-YEAR WSEL
5044.27
3.10
100-YEAR WSEL 5045.355
13.19
100-YEAR WSEL
5044.96
6.68
A.
SHEAR ENGINEERING CORPORATION
PAGE 13
OUTLET STRUCTURE FOR AURORA HILLS SUBDIVISION
PROTECT: AURORA HILLS SUBDIVISION DATE: 04/28/98
PROJECT NO 1005-42-95 BY HBO
PROJECT LOCATION :SKYWAY DRIVE FILE NAME: SKYPOND
+r+r+r+ •+r+r+r r•+:+rr *OUTPUT* +r+t+rr +rtrr++ r+r+r+r r++::+r trrttr* t+t+ttr trt+tt+ tr+rt++
OVERFLOW SPILLWAY
HEAD HEAD HEAD SUB HEAD
BLEV. OVER LOWER OVER UPPER OVER WEIR TOTAL OVER WEIR TOTAL BLEV.
LOWER ORIFICE UPPER ORIFICE WEIR PLOW FLOW WEIR FLOW FLOW
ORIFICE PLOW ORIFICE FLOW
ft ft cfe ft cfe ft cfs cfs ft cfe cfs ft
5042.64 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5042.64
5043.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5043.00
5043.75 0.73 1.98 0.00 0.00 0.00 0.00 1.98 0.00 0.00 1.98 5043.75
5043.94 0.93 2.22 0.00 0.00 0.00 0.00 2.22 0.00 0.00 2.22 5043.94
5044.00 0.98 2.29 0.00 0.00 0.00 0.00 2.29 0.00 0.00 2.29 5044.00
5044.27 1.25 2.58 0.02 0.52 0.00 0.00 3.10 0.00 0.00 3.10 5044.27
5044.304 1.29 2.62 0.05 0.95 0.00 0.00 3.57 0.00 0.00, 3.57 5044.30
5044.848. 1.83 3.12 0.60 3.17 0.00 0.00 6.29 0.00 -0.00 6.29 5044.85
5044.96 1.95 3.22 0.71 3.46 0.00 0.00 6.68 0.00 0.00 -6.68 5044.96
5045.00 1.98 3.25- 0..75 3.55 0.00 0.00 6.79 0.00 0.00 6.79 5045.00
5045.10 2.09 3.33 0.85 3.78 0.00 0.00 7.10 0.00 0.00 7.10 5045.10
5045.355 2.34 3.53 1.10 4.31 0.25 5.36 13.19 0.00 0.00 13.19 5045.36
5046.00 2.98 3.98 1.75 5.42 0.90 35.52 44.92 0.00 0.00 44.92 5046.00
5046.50 3.48 4.30 2.25 6.15 1.40 68.91 79.36 0.00 0.00 79.36 5046.50
5047.00 3.98 4.60 2.75 6.79 1.90 108.95 120.34 0.50 18.38 138.73 5047.00
r+rrr+r+ r+r+rr+t ++r+t t+r ttrrrtrt trtttrtt tr++t+rt trrrrr+t ttr+trrr rtrt++tr r+tr++:+ rt+++trr rt+++tr+
ORIFICE EQUATION: CA(29H)^1/2 WEIR PLOW EQTN. : CwLHA3/2
NOTE: HEAD OVER ORIFICE - HEAD OVER CENTER OF ORIFICE
ACTUAL 2 -YEAR WATER SURFACE ELEVATION - 5044.304 FEET VOLUME REACHED
ACTUAL 10 -YRAR WATER SURFACE ELEVATION - 5044.848 FEET VOLUME REACHED
ACTUAL 100 -YEAR WATER SURFACE ELEVATION - 5045.355 FEET VOLUME REACHED
REQUIRED 2 - YEAR RELEASE RATE= 3.57 CPS VERSUS ACTUAL 0 REQUIRED WSEL = 2.22 CPS OK
REQUIRED 10 - YEAR RELEASE RATE - 6.29 CPS VERSUS ACTUAL 0 REQUIRED WSEL = 3.10 CPS OK
REQUIRED 100 - YEAR RELEASE RATE = 13.18 CPS VERSUS ACTUAL W REQUIRED WSEL = 6.68 CPS OK
ACTUAL 2 - YEAR RELEASE RATE = 3.57 CPS W ACTUAL WSEL
ACTUAL 10 - YEAR RELEASE RATE - 6.29 CPS 0 ACTUAL WSEL
ACTUAL 100 - YEAR RELEASE RATE - 13.19 CPS W ACTUAL WSEL
2 - YEAR PREEBOARD - 2.70 FEET VERSUS POND FREEBOARD 2.56 FREEBOARD OK
10 - YEAR FREEBOARD - 2.15 FEET 2.23 FREEBOARD OK
100 - YEAR FREEBOARD.= 1.65 PBHT 1.54 FREEBOARD OK
SHEAR ENGINEERING CORPORATION
PAGE 14
SIDEWALK CULVERT SIZING
PROJECT: AURORA HILLS DATE: 12/02/97
FILE: CULVERT By: MEO
PROD NO.:1005-42-94 LOCATION:SKYWAY DRIVE
DESIGN POINT D CORNER OF SKYWAY DRIVE AND POLARIS DRIVE
Q100 = 8.37
ASSUME 0.75 ON SKYWAY DRIVE = 6.28 CPS
0.25 ON POLARIS DRIVE = 2.09 CPS
rrrrrrrr r:rr♦+rr+♦rr+rrrrrr•rrrr rrrrrrrrr+r+rrrrrrrrra rr++r+rr+rxr:+rrrrterrrrrrrrrxerrrrr
POLARIS DRIVE
SLOPE (S) = 0.02 FT/PT CROSS SLOPE (Sx) 0.02 FT/FT N = 0.016
T = 7.00 FT SEE LOCAL STREET CAPACITY VERSUS DEPTH TABLE
Dw=Sx(T-2) = 0.10 FOR SLOPE = 2.0%
FROM FIGURE 5-6 DELTA Qi/Q = 0.72
1-DELTA Qi/Q = 0.28 EQUALS Qi/Q FOR TABLE 5-5
USE Qi/Q = 0.30
INLET LENGTH REQUIRED FROM TABLE 5-5 FOR 100i INTERCEPT = 2.50 FEET
CONCLUDE:INSTALL 4 FOOT SIDEWALK CULVERT Qi/Q = 0.45 FROM FIGURE 5-5
Qi/Q + DELTA Qi/Q= 1.17 THEREFORE Qi = 2.45 CPS (THEORETICAL)
APPLY REDUCTION FACTOR OF 0.85 Qi = 2.08 CPS (ACTUAL)
BYPASS FLOW 0.01 CPS NEGLIGIBLE
•rrr rrr rrrrr+rr rr+rr:rerrrrrrr•rrrrrrrrrrr++++rr:rrerr•re rrrrrrr++rr+rr++r+++r++r+rr++++++
SKYWAY DRIVE
SLOPE (S) = 0.02 FT/FT CROSS SLOPE (Sx) 0.02 FT/PT N 0.016
T = 11.00 FT SEE SKYWAY CAPACITY VERSUS DEPTH TABLE
Dw = 0.18 FOR SLOPE = 2.0!k SKYWAY ASSUMED TO BE 50' FLOWLINE TO FLOWLINE
FROM FIGURE 5-6 DELTA Qi/Q = 0.27
1-DELTA Qi/Q - 0.73 EQUALS Qi/Q FOR TABLE 5-5
USE Qi/Q = 0.70
INLET LENGTH REQUIRED FROM TABLE 5-5 FOR 100% INTERCEPT 16.00 FEET
CONCLUDE:INSTALL 8 FOOT SIDEWALK CULVERT Qi/Q 0.60 FROM FIGURE 5-5
Qi/Q + DELTA Qi/Q= 0.87 THEREFORE Qi = 5.46 CPS (THEORETICAL)
APPLY REDUCTION FACTOR OF 0.85 Qi = 4.64 CPS (ACTUAL)
BYPASS FLOW = 1.64 CPS NEGLIGIBLE
8
Capacity versus Depth for Local Street slope =2%
Rating Table for Irregular Channel
Project Description
Project File
c:\haestad\fmw\streets.fm2
Worksheet
Local - Aurora Hills
Flow Element
Irregular Channel
Method
Manning's Formula
Solve For
Discharge
Constant Data
Channel Slooe 0.020000 ft/ft
SSUrss1:.
ZS 1, 1" PO\4-r) 5 Z Z U(l
Input Data
Minimum
Maximum
Increment
Water Surface Elevation
99.57
100.41
0.02 ft
Rating Table
Water Surface
Elevation
(ft)
Wtd. Mannings
Coefficient
Discharge
(cfs)
Velocity
(ft/s)
99.57
0.016
0.33
1.88
99.59
0.016
0.45
1.74
99.61
0.016
0.70
1.82
99.63
0.016
1.08
1.96
99.65
0.016
1.63
2.13
99.67
0.016
2.35
2.31
69
0.016
3.27
2.49
99.71
0.016
4.4
2.66
99.73
0.016
5.78
2.84
99.75
0.016
7.42
3.02
99.77
0.016
9.32
3.19
99.79
0.016
11.52
3.35
99.81
0.016
14.03
3.52
99.83
0.016
16.86
3.68
99.85
0.016
26.63
3.84
99.87
0.016
22.84
3.86
99.89
0.016
26.18
3.91
99.91
0.016
30.08
3.98
99.93
0.016
34.57
4.07
99.95
0.017
38.58
4.08
99.97
0.018
42.86
4.10
99.99
0.018
47.39
4.12
100.01
0.017
58.73
4.67
100.03
0.017
66.93
4.90
100.05
0.017
75.56
5.13
100.07
0.017 '
84.61
5.35
Fd, Gi= Z,1c7- 112, s}f P
Ost QL-- A,-Z o��ci��✓
12/01/97 FlowMaster v5.13
09:31:43 AM Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 (203) 7551666 Page 1 of 2
Capacity versus Depth for Local Street slope =2%
Rating Table for Irregular Channel
Rating Table
Water Surface
Elevation Wtd. Mannings Discharge Velocity
(ft) Coefficient (cfs) (fus)
100.09,
0.017
94.07
5.57
100.11
0.019
96.52
5.37
100.13
0.019
106.27
5.58
100.15
0.019
116.37
5.78
100.17
0.016
148.50
7.00
100.19
0.016
160.67
7.21
100.21
0.016
173.23
7.41
100.23
0.016
186.16
7.61
100.25
0.016
199.47
7.81
100.27
0.016
213.15
8.01
100.29
0.016
227.19
8.20
100.31
0.016
241.59
8.40
100.33
0.016
256.33
8.59
100.35
0.016
271.43
8.77
100.37
0.016
286.87
8.96
100.39
0.016
302.65
9.14
100.41
0.016
318.76
9.33
12/01/97 FlowMaster v5.13
09:31:43 AM Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755-1666 Page 2 of 2
Flow -capacity verus depth in Skyway
Rating Table for Irregular Channel
Project Description
Project File
c:\haestad\fmw\streets.fm2
Worksheet
50' road w/ vertical curb in 76 foot ROW
Flow Element
Irregular Channel
Method
Manning'sFormula
S�.t�Wh,
Solve For
Discharge
\00 1N
Constant Data
Channel Slope 0.020000 ft/ft
Input Data
Minimum Maximum
Increment
Water Surface Elevation 100.17 101.13
0.01 ft
Rating Table
Water Surface
Elevation
Wtd. Mannings Discharge
Velocity
(ft)
Coefficient (cfs)
(ft/s)
100.17
0.016
0.82
2.40
0 3C1-0.11
= U
100.18
0.016
0.87
2.27
,ZZ
100.19
0.016
0.97
2.21
100.20
0.016
1.11
2.19
U ZZ /o-L _
I
100.21
0.016
1.28
2.20
,0
100.22
0.016
1.49
2.24
100.23
0.016
1.74
2.28
100.24
0.016
2.02
2.34
100.25
0.016
2.36
2.40
100.26
0.016
2.73
2.47
100.27
0.016
3.15
2.54
100.28
0.016
3.62
2.62
100.29
0.016
4.15
2.69
100.30
0.016
4.72
2.77
100.31
0.016
5.35
2.85
100.32
0.016
6.04
2.92
100.33
0.016
6.79
3.00
100.34
0.016
7.59
3.08
100.35
0.016
8.47
3.16
100.36
0.016
9.40
3.24
100.37
0.016
10.41
3.32
100.38
0.016
11.49
3.39
00.3
0.016
2.63
3.47
100.40
0.016
13.85
3.55
100.41
0.016
15.15
3.62
100.42
0.016
16.52
3.70
12/01/97
-
FlowMaster v5.13
10:51:05 AM Haestad
Methods, Inc.
37 Brookside Road
Waterbury, CT 06708
(203) 755-1666
Page 1 of 3
Flow capacity verus depth in Skyway
Rating Table for Irregular Channel
Rating Table
Water Surface
Elevation Wtd. Mannings. Discharge Velocity
(ft) Coefficient (cfs) MIS)
100.43
0.016
17.97
3.78
100.44
0.016
19.51
3.85
100.45
0.016
21.12
3.93
100.46
0.016
22.82
4.00
100.47
0.016
24.61
4.07
100.48
0.016
26.48
4.15
100.49
0.016
28.45
4.22
100.50
0.016
30.50
4.29
100.51
0.016
31.67
4.23
100.52
0.016
32.99
4.18
100.53
0.017
34.46
4.15
100.54
0.017
36.07
4.13
100.55
0.017
37.83
4.11
100.56
0.017
39.72
4.10
100.57
0.017
41.74
4.10
100.58
0.017
43.91
4.10
100.59
0.018
46.21
4.11
100.60
0.018
48.65
4.12
100.61
0.018
51.22
4.14
100.62
0.018
53.94
4.15
100.63
0.018
56.80
4.17
100.64
0.018
60.28
4.23
100.65
0.018
63.85
4.29
100.66
0.018
67.53
4.35
100.67
0.018
71.83
4.43
100.68
0.018
76.27
4.52 .
100.69
0.018
80.85
4.60
100.70
0.018
85.58
4.69
100.71
0.018
90.46
4.77
100.72
0.018
95.48
4.85
100.73
0.018
100.65
4.93
100.74
0.018
105.97
5.01
100.75
0.018
111.44
5.09
100.76
0.018
117.06
5.17
100.77
0.018
123.63
5.28
100.78
0.018
130.34
5.39
100.79
0.018
137.19
5.51
100.80
0.018
144.17
5.61
100.81
0.018
151.29
5.72
100.82
0.018
158.54
5.83
100.83
0.016
186.35
6.66
100.84
0.016
194.39
6.77
100.85
0.016
202.57
6.87
100.86
0.016
210.88
6.97
100.87
0.016
219.33
7.08
12/01/97
FlowMaster v5.13
10:51:05 AM
Haestad Methods, Inc.
37 Brookside Road
Waterbury, CT 06708 (203) 755-1666 Page 2 of 3
8:
Flow capacity verus depth in Skyway
Rating Table for Irregular Channel
Rating Table
Water Surface
Elevation Wtd. Mannings Discharge Velocity
(ft) Coefficient (cfs) (ft/s)
100.88
0.016
227.92
7.18
100.89
0.016
236.64
7.28
100.90
0.016
245.49
7.38
100.91
0.016
254.46
7.48
100.92
0.016
263.57
7.57
100.93
0.016
272.81
7.67
100.94
0.016
282.17
7.77
100.95
0.016
291.65
7.87
100.96
0.016
301.26
7.96
100.97
0.016
310.99
8.06
100.98
0.016
320.85
8.15
100.99
0.016
330.82
8.25
101.00
0.016
340.92
8.34
101.01
0.016
351.13
8.43
101.02
0.016
361.46
8.52
101.03
0.016
371.91
8.62
101.04
0.017
382.47
8.71
101.05
0.017.
393.15
8.80
101.06
0.017
403.94
8.89
101.07
0.017
414.84
8.98
101.08
0.017
425.86
9.07
101.09
0.017
436.99
9.16
101.10
0.017
448.23
9.25
101.11
0.017
459.58
9.33
101.12
0.017
471.04
9.42
101.13
0.017
482.60
9.51
12/01/97 FlowMaster v5.13
10:51:05 AM Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755-1666 Page 3 of 3
APPENDIX H
Charts and Tables
Details
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Table 4.2.6-1
Runoff Coefficients for Rational Method
(From: American Soc. of Civil Engineers and Water
Pollution Control Fed. 119701 and Seelye (19601)
Character of surface Runoff coefficients
Ranee Recommended
Pavement —asphalt or concrete 0.70-0.95 0.90
Gravel, from clean and loose
to clayey and compact 0.25-0.70 0.50
Roofs 0.70-0.95 0.90
Lawns (irrigated) sandy soil
Flat, 2 percent
0.05-0.15
0.10
Average, 2 to 7 percent
0.15-0.20
0.17
Steep, 7 percent or more
0.20-0.30
0.25
Lawns (irrigated) heavy soil
Flat, 2 percent
0.13-0.17
0.15
Average, 2 to'7 percent
0.18-0.22
0.20
.Steep. 7 percent
0.25-0.35
0.30
Pasture and non -irrigated lawns
Sand
Bare
0.15-0.50
0.30
Light vegetation
0.10-0.40
0.25
Loam
Bare
0.20-0.60
0.40
Light vegetation
0.10-0.45
0.30
Clay
Bare
0.30-0.75
0.50
Light vegetation
0.20-0.60
0.40
Composite areas
Urban
Single-family, 4-6 units/acre
0.25-0.50
0.40
Mult!-family, >6 units/acre
0.50-0.75
0.60
Rural (mostly non -irrigated lawn area)
<1/2 acre - 1 acre
0.20-0.50
0.35
1 acre - 3 acres
0.15-0.50
0.30
Industrial
Light
0.50-0.80
0.65
Heavy
0.60-0.90
0.75
Business
Downtown
0.70-0.95
0.85
Neighborhood
0.50-0.70
0.60
Parks
0.10-0.40
0.20
Rural open space
LCS-WM Manuel 4.2--4 April 1979
LOVELAND
STORM DRAINAGE CRITERIA MANUAL FIGURE 1201
DETENTION POND OUTLET CONFIGURATIONS
Headwater for I fool Min. freeboord-1
weir flow
' 1_77
00 year water surface /
p /O year water surface
T Headwater for
Pond invert 10 year flow —
(trickle channel)
ii
Grated inlet capacity
greater than twice 10
year discharge
Top of berm
l00 year overflow crest
Erosion protection
on D/S slope
Overflow
spillway
Drop inlet Provide adequate pipe slope
inlet
insure throat control
10 year control of throat
of outlet pipe, orifice plate
may be required
TYPE / OUTLET
No Scale
Slope
Outlet pipe lO year
capacity (18"0 Min.)
Design head for l fool Min. freeboord� Top of berm
weir flow
l00 year water surface
/0 year water surface
�. Headwater for
Pond invert
a: l00 year flow
(trickle channel)
I
Headwater for
l0 year flow —
Orifice opening
l00 year control at throat
of outlet pipe, orifice plate
may be required
TYPE 2 OUTLET
No Scale
Outlet pipe l00 year
capacity (18"0 Min.)
WRC ENG.
REFERENCE:
It is often desirable to develop a composite runoff coefficient
based on the percentage of different types of surface in the drainage
area. This procedure is often applied to typical "sample" blocks as a
guide to selection of reasonable values of the coefficient for an entire
area.
The range and recommended (Table 4.2.6-1) coefficients are appli-
cable for stoma of 5-year to 10-year frequencies. Less frequent higher -
intensity stomas will require modification of the coefficient because
infiltration and otherlosseshave a proportionally smaller effect on
runoff (see Section 4.7.8.7).
The adjustment of the Rational Method for use with major atoms
can be made by multiplying the right side of the Rational Formula by a
frequency factor Cf (Wright -McLaughlin Engineers, 1969), which is used
to account for antecedent precipitation conditions. The Rational Formula
now becomes:
Q - CCf IA (Eq. 4.2.6-1)
where:
Recurrence
Interval
Cf
(years)
—
2 to 10
1.0
25
1.1
50
1.2
100
1.25
The product of C times Cf should not exceed 1.0.
4.2.7 Application of the Rational Method
The first step in applying the Rational Method is to obtain a good
topographic map and define the boundaries of all of the relevant drain-
age basins. Basins to be defined Include all basins tributary to the
area of study and subbaslns in the study area. A field check and possi-
bly field surveys should be made for each basin.
The major storm drainage basin does not always coincide with the
minor storm drainage basin. This to often the case in urban areas where
a low flow will stay next to a curb and follow the lowest grade, but
when a large flow occurs the water will be deep enough so that part of
the water will overflow street crowns and flow Into a new subbasin.
LCS-WM Manual 4.2 --- 6 April 1979
0
ENU
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Figure 4.2.4-1 SURFACE FLOW TIME CURVES
( From : Dept. of Traneportotlon, 19701
4.2--5
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APPENDIX III
Portion of City of Fort Collins Drainage Basin Map
Exhibits from Fossil Creek Drainage Basin Master Drainage way Planning Study
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FOSSIL CREEK
DRAINAGE STUDY
SCALE
BASIN VICINITY MAP
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IN \WWW \um ma, " YW ,. ,. if Ix DESIGNATION
L FA''A /'Dj-- 1 \ p ) -'se I Q °u°NAM"Des O"PUNT
5Zµ -r SOUTH BASIN DESIGN POINT
FLOW DIRECTION
B 49 n - °S r 1 Se Tz
FMVnMI I- ~ EROSION CONTROL LEGEND
GRAVEL INLET FILTER
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NVIEINIE AP L I9YR __ Dam SEE amI FREDERICK LAND SURVEYING DRE DRAINAGE AND EROSION CONTROL PLAN reoxn s. SORER xa69
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°b • °i1°R' SefP /aale,Ra Orr PHONE: (4T0) eea-S6E2 WARMER COUNTY, COLORADO 84 _04-800 4 8
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