HomeMy WebLinkAboutDrainage Reports - 01/08/1996Final roved Report
F.
SHEAR
YORTCOLLINS EKGMSM
rut u' 't III
Final Drainage and Erosion Control Report
for
LOTS 5 & 6, BLOCK 5, REPLAT (NO. 1) OF EVERGREEN PARK
Fort Collins, Colorado
Prepared for:
Greg D. Fisher, Architect
3115 Clyde Street
Ft. Collins, Colorado 80524
Prepared by:
SHEAR ENGINEERING CORPORATION
Project No: 1498-01-95
DATE: December, 1995
4836 S. College, Suite 12 Ft. Collins, CO 80525 (970) 226-5334 FAX (970) 282-031 1
November 27, 1995
Project'No: 1498-01-95
Basil Hamdan
City of Ft. Collins Stormwater Utility
P.O. Box 580
Ft. Collins, Colorado 80524
Re: Lots 5 & 6, Block 5, Replat (No.1) of Evergreen Park; R. Collins, Colorado
Dear Basil,
Enclosed, please find the Final Drainage and Erosion Control Report for Lots 5 & 6, Block 5,
Replat (No. 1) of Evergreen Park. The hydrology data and the hydraulic analysis presented in
this report complies with the requirements of the City of Fort Collins Storm Drainage Criteria
Manual; dated March, 1984, and the Erosion Control Reference Manual.
The plan and report have been revised according to your comments dated October 26, 1995. We
have also made the revisions that you recommended at our meeting on Tuesday; November 21,
1995.
If you have any questions or comments, please call me or Mark Oberschmidt at 226-5334.
Sincerely,
Brian W. Shear, P.E.
Shear Engineering Corporation
BWS / meo
cc: Greg Fisher, Architect
Sierra Builders
4836 S. College, Suite 12 Ft. Collins, CO 80525 (970) 226-5334 FAX (970) 282-031 1
PAGE 1
Final Drainage and Erosion Control Report
Lots 5 & 6, Block 5, Replat (No. 1) of Evergreen Park
L
H.
GENERAL LOCATION AND DESCRIPTION:
A. Location
1. Lots 5 and 6, Block 5, Replat (No. 1) of Evergreen Park is located in the Northeast
One -Quarter of Section 1, T7N, Range 69 West of the 6th P.M., R. Collins,
(Larimer County), Colorado. These are existing platted lots.
2. More specifically, Lots 5 and 6, Block 5, Replat (No. 1) of Evergreen Park are
located on the east side of Blue Spruce Drive approximately 750 feet north of
Conifer Drive in the Northeast part of Fort Collins, Colorado (See Vicinity Map).
a. Blue Spruce Drive is an existing street with sewer, water, curb' and gutter and
street paving installed. These improvements were installed with the final utility
plans for Replat (No. 1) of Evergreen Park.
3. The initial phase of this project will consist of the following:
* 2 - 200' x 60' buildings
* An access drive and parking areas
* stormwater detention facilities for the entire site
The second phase will consist of the following:
* 2 - 64' x 40' storage buildings
* Additional parking and loading areas
B. Description of Property
1. The site is currently undeveloped and
primarily of native dry land grasses.
2. The site area is approximately 1.76 'acres.
open. Existing ground. cover consists
3. There are no major drainage ways located on or within the project site. An existing
regional detention pond (Evergreen West Pond) outfall channel is located east of
this property (See Drainage and Erosion Control Plan in stuffer envelope).
4. There are no irrigation canals or systems located on or within 100' of the project
site. i
DRAINAGE BASINS AND SUB -BASINS:
A. Major Basin Description
1. The site is situated within the Greenbriar-Evergreen Drainage Basin as designated
on the City of Fort Collins Stormwater Basin Map. The Master Drainage Plan for
the Greenbriar-Evergreen Basin is currently being amended.
PAGE 2
Final Drainage and Erosion Control Report
Lots 5 & 6, Block 5, Replat (No. 1) of Evergreen Park
H. DRAINAGE BASINS AND SUB -BASINS:
A. Major Basin Description (continued)
a. The Basin fee rate for the Greenbriar-Evergreen Basin is $ 10,000 per gross acre
according to the development fee section of the City of Fort Collins
Development Manual.
b. This may be reduced if detention is provided.
B. Sub -Basin. Description
1. A majority of the site is situated within Basin 4U (undeveloped) as defined with the
preliminary amended Greenbriar-Evergreen Basin Master Drainage Plan. This is the
western portion of the site. See Exhibit from preliminary amended Greenbriar-
Evergreen Basin Master Drainage Plan included with the Drainage and Erosion
Control Plan in the staffer envelope.
a. Page 20 of the draft of Greenbriar-Evergreen Basin Master Drainage Plan
indicates the following:
BASIN 4U. The basin was assumed to be completely developed for commercial
use with an estimated imperviousness of 90 percent. On -site detention would be
required for this basin. The allowable release from this basin is 17 cfs, or 0.47
cfs/acre. The designated release point for Basin 4U is the storm sewer and street
along Conifer Street which convey flows easterly to Pond 5 (conceptual). The
detention volume required for the basin, in order to meet the prescribed release
rate, was estimated to be 6.4 acre feet.
2. The remainder of the site is situated within Basin 3B as defined with the
preliminary amended Greenbriar-Evergreen Basin Master Drainage Plan. This is the
eastern portion of the site. See Exhibit from preliminary amended Greenbriar-
Evergreen Park Master Drainage Plan included with the Drainage and Erosion
Control Plan in the stuffer envelope.
a. Page 20 of the draft of the Amended Greenbriar-Evergreen Basin Master
Drainage Plan indicates the following:
BASIN 3B. The basin was assumed to be developed for 37 percent commercial
use, and 63 percent residential housing at levels representing 11, 49 and 3
percent of the entire basin for high, medium and low densities, respectively.
The result is a developed imperviousness of 63 percent. On -site detention
to the existing Evergreen West Pond. Overflow from this pond would enter the
existing outlet channel which would transport flow southerly to Pond 5
(conceptual).
PAGE 3
Final Drainage and Erosion Control Report
Lots ' 5 & 6, Block 5, Replat (No. 1) of Evergreen Park
1L DRAINAGE BASINS AND SUB -BASINS:
B. Sub -Basin Description (continued)
3. Existing site grades indicate that historic flows are conveyed easterly towards the
Evergreen West detention pond and outfall channel which are located within Basin
3B of the preliminary amended Greenbriar-Evergreen Master Drainage Plan.
III. DRAINAGE AND EROSION CONTROL DESIGN CRITERIA:
A. Regulations
1. All storm drainage design criteria from the City of Fort Collins Drainage Criteria
Manual was followed.
2. Storm Drainage design criteria modification was considered based on data provided
by City of Fort Collins Stormwater Utility personnel concerning conclusions
presented with the preliminary amended Greenbriar-Evergreen Park Master
Drainage Plan.
3. All erasion control design criteria from the City of Fort Collins Erosion Control
Reference Manual.
B. Development Criteria Reference and Constraints
1. Previous studies which were considered include:
a. Greenbriar-Evergreen Park Master Drainage Plan; Engineering Professionals
b. A draft of the Amended Greenbriar-Evergreen Basin Master Drainage Plan;
Lidstone & Anderson, Inc.; Project No COTST05.4; dated September 6, 1994.
2. Blue Spruce Drive is developed and paved. There are no underground storm
drainage facilities. Detention pond outfalls on the west side of the property are
therefore, restricted to surface release to Blue Spruce Drive.
3. New American Disabilities Act (ADA) requirements affect the final parking lot
grading design. Maximum allowable design grades for handicap parking, and
access from the public right-of-way effect the drive and parking lot final grading
which typically affects detention volumes.
4. Lot 7, which is located to to the south of Lot 6, is completely developed. The
existing parking lot is paved up to the Lot 6 south property line. This restricts the .
final grading along the common property line of lots 6 & 7.
PAGE 4
Final Drainage and Erosion Control Report
Lots 5 & 6, Block 5, Replat (No. 1) of Evergreen Park
III. DRAINAGE AND EROSION CONTROL DESIGN CRITERIA:
C. Hydrological Criteria
1. The Rational method (Q = CIA) was used to determine the pre -developed and post
development peak flows for the 10 and 100-year storm events (commercial
requirements).
2. The Cumulative Runoff Method was used to determine the required detention
volume.
a. The 100-Year storm was used as the design storm.
3. The release rate from the western detention pond is based on the requirements of
the Greenbriar-Evergreen Basin Master Drainage Plan (0.47 cfs/acre).
a. The area used to size the pond consists of that portion of the site and 1/2 ROW
of Blue Spruce Drive which are located in Basin 4 as delineated on the
Greenbriar-Evergreen Basin Master Drainage Plan.
4. The release rate from the eastern detention pond is based on the post development
100-year peak flow which would be produced by that portion of the site which is
located in Basin 3B as delineated on the Greenbriar-Evergreen Basin Master
Drainage Plan.
a. Stormwater from Basin 3B is may be released undetained to the Evergreen
West regional detention pond according to the Greenbriar-Evergreen Basin
Master Drainage Plan.
D.. Hydraulic Criteria
1. Orifice and weir equations and coefficients suggested by the City of Fort Collins
Storm Drainage Criteria Manual were used.
IN. DRAINAGE FACILITY DESIGN:
A. General Concept
1. The stormwater from the site will be directed to the east and west by creating a high
point near the center of the property.
2. Detention pond release from the western portion of the property (sub -basin Iw) will
occur at two (2) locations
a. The outlet will consist of curbed channel and sidewalk culvert to the flowline of
the existing Blue Spruce Drive curb and gutter.
b. Flows are conveyed southerly in the Blue Spruce Drive flowline to Conifer
Street.
PAGE 5
Final Drainage and Erosion Control Report
Lots 5 & 6, Block 5, Replat (No. 1) of Evergreen Park
IV. DRAINAGE FACILITY DESIGN:
A. General Concept (continued)
3. A portion of sub -basin Ie (minor basin Ie,$) may be released undetained to the
Evergreen West detention pond according to the Preliminary Amended Greenbriar-
Evergreen Master Drainage Plan. Additional detention volume is provided to
account for the portion of sub -basin Ie which is located in Basin 4U as delineated in
the Greenbriar-Evergreen Master Plan.
a. Detention pond release from the eastern portion of the property will occur via an
inlet in sump condition with an outlet pipe to the Evergreen West detention
pond.
B. Specific Details
1. The westernmost detention storage areas have been divided between the two (2)
parking areas located at the western end of the proposed buildings. The release rate
is based on requirements of the Amended Greenbriar-Evergreen Master Drainage
Plan.
a. The runoff coefficient utilized with the Cumulative Runoff method for sizing
both detention ponds is 1.00.
2. The area used to determine the release rate form the western pond consists of the
1/2 R.O.W. of Blue Spruce Drive and the western portion of the site (sub basins
Irow, Iw & Ie4). The total area equals 1.51 acres. The release rate used in the
design of the pond (0.71 cfs) is based on the requirements of the Amended
Greenbriar/Evergreen Master Drainage Plan (0.47 cfs / acre) (Refer to page 3 in the
calculations).
a. The required detention pond storage volume according to the Cumulative
Runoff method, utilizing a runoff coefficient of 1.00, is 6,939 cubic feet. Refer
to Page 3, Appendix I for the detention pond volume calculations.
b. The actual volume provided in the western detention pond is 10,120 cubic feet.
Refer to pages 6 & 6a , Appendix I for the Stage -Storage calculations.
c. The finished floor elevation for both buildings in phase 1, is set at an elevation
of 70.50 feet.
d. The estimated 100-Year Water Surface Elevation (W.S.EI.) in the west pond is
69.58 feet.
e. The freeboard provided is 0.24 feet.
f. The separation provided between the estimated 100-Year W.S.EI. and the
finished floor elevations of the two (2) office / warehouse buildings, is 0.92 feet.
PAGE 6
Final Drainage and Erosion Control Report
Lots 5 & 6, Block 5, Replat (No.1) of Evergreen Park
IV. DRAINAGE FACILITY DESIGN:
B. Specific Details (continued)
3. The Cumulative Runoff Method was utilized to determine the storage volume
requirements for the western detention pond. The following items outline the final
design. details of the westernmost detention ponds.
a. A berm will be constructed around the westernmost parking lots in order to
define a detention pond high water elevation.
i. The top of the berm along Blue S7ruce Drive will be set at an elevation of
69.82 feet. High curbs or landscape timbers are required on the south side
of the south parking lot in order to achieve the required high water
elevation.
ii. The side slopes on the berths are 4:1.
iii. The high point located in the entry drive and all the curb at the southern end
. of the parking lot is set at an elevation of 69.82 feet.
b. The two (2) outlets from the west parking lot detention pond will consist of the
following:
i. A 3 inch diameter orifice in a headwall located at the R.O.W. line.
ii 10 LF of a 24" wide concrete channel at 0.5% from the back of the curb in
the parking lot to the back of walk.
iii. A 24" wide metal sidewalk culvert.
c. The top of the headwall will act as an overflow weir.
i. The top of the headwall is set at an elevation of 69.58 feet in order to ensure
that the storage requirement is met. Refer to the stage storage curves in the
calculations.
d. The 3 (3") inch diameter orifice is sized to restrict the release rates from the
ponds to approximately 0.355 cfs. This is one half of the allowable release rate
(0.71 cfs) because the flows are directed towards two (2) separate detention
areas
4. The high point in the entry drive and the high curb at the southern end of the
parking area will act as emergency overflow weirs for the site.
PAGE 7
Final Drainage and Erosion Control Report
Lots 5 & 6, Block 5, Replat (No. 1) of Evergreen Park
IV. DRAINAGE FACILITY DESIGN:
B. Specific Details (continued)
5. An access, utility and drainage easement will be required due to the limits of the
detention pond and because of joint access. Replat (No. 1) of Evergreen Park is a
recorded plat. Therefore, the access, utility and drainage easement must be
dedicated by separate document. The drainage easement exhibit is included with
Appendix IV for reference.
6. Detention is also provided in the eastern portion of the site (Sub basin Ie).
7. We have to size the pond to store a portion of the developed 100-year storm from
sub -basin Ie.
a. The total area of sub -basin Ie is 0.94 acres.
b. The release rate used in the design of the pond (3.07 cfs) is based on our
discussions with the staff of the City of Fort Collins Stormwater Utility.
i. It was agreed that the release rate for the eastern pond would be the peak
100-year flow developed by sub basin Ie,B (0.43 acres) using post developed
conditions.
ii. Sub basin Iem is the portion of sub basin Ie which is located in Basin 3B as
delineated on the Greenbriar-Evergreen Basin Master Drainage Plan.
c. The required detention pond storage volume according to the Cumulative
Runoff method, utilizing a runoff coefficient of 1.00, is 2,364 cubic feet. Refer
to Page 4, Appendix I for the detention pond volume calculations.
d. The actual volume provided in the eastern pond is 7373 cubic feet. Refer to
pages 7 & 7a , Appendix I for the Stage -Storage calculations.
e. The estimated 100-Year Water Surface Elevation (W.S.EI.) in the east pond is
69.14 feet.
f. The finished floor elevation for both buildings in phase 2 is set at an elevation
of 70.00 feet.
g. The freeboard provided is 0.68 feet.
h. The separation provided between the estimated 100-Year W.S.EI. and the
finished floor elevations of the two (2) future storage buildings is 0.86 feet.
PAGE 8
Final Drainage and Erosion Control Report
Lots 5 & 6, Block 5, Replat (No.1) of Evergreen Park
IV. DRAINAGE FACILITY DESIGN:
B. Specific Details (continued)
8. The Cumulative Runoff Method was utilized to determine the storage volume
requirements for the eastern detention pond. The following items outline the design
criteria and the final design details of the westernmost detention ponds.
a. A berm will be constructed around the westernmost parking lot in order to
define a detention pond high water elevation.
i. The top of the berm along the eastern property line will be set at an
elevation of 70.00 feet. An emergency overflow weir will be set an
elevation of 69.30 feet. This elevation is set in order to insure that a
maximum depth of flow in the pond of approximately 1.50 feet will not be
exceeded.
I The side slopes on the berms are 4:1.
9. The outlet structure for the eastern detention pond will consist of the following:
a. an area inlet in sump condition,
i. The grate elevation of the inlet is set at an elevation 67.80 feet.
I The invert of the outlet pipe is set an elevation of 64.80 feet.
iii. A orifice plate with a 0.60 foot diameter orifice is to be attached to the
inside face of the area inlet to restrict the flows to 3.07 cfs.
b. 104 lineal feet 18" ADS N-12 at 0.46%,
i. The capacity of the pipe based on a Headwater to Depth ratio (HW/D) of
1.00 is 7.72 cfs .
c. an emergency overflow weir in the berm along the eastern property line at an
elevation of 69.30 feet.
PAGE 9
Final Drainage and Erosion Control Report
Lots 5 & 6, Block 5, Replat (No. 1) of Evergreen Park
V. EROSION CONTROL:
A. General Concept
1. Erosion control measures will be as identified on the Drainage and Erosion Control
Plan.
2. An erosion control security deposit is required in accordance with City of Fort
Collins policy (Chapter 7, Section C : SECURITY; page 7.23 of the City of Fort
Collins Development Manual). In no instance shall the amount of the security be
less than $1000.00.
3. According to current City of Fort Collins policy, the erosion control security deposit
is figured based on the larger amount of 1.5 times the estimated cost of installing
the approved erosion control measures or 1.5 times the cost to re -vegetate the
anticipated area to be disturbed by construction activity.
i The cost to install the proposed erosion control measures is approximately
$1,035.00. Refer to the cost estimate attached in Appendix I. 1.5 times the cost
to install the erosion control measures is $ 1,552.50.
ii. Based on current data provided by the City of Fort Collins Stormwater Utility,
and based on an actual anticipated net affected area which will be disturbed by
construction activity (approximately 1.76 acres), we estimate that the cost to re -
vegetate the disturbed area will be $1,144.00 ($650.00 per acre x 1.76 acres).
1.5 times the cost to re -vegetate the disturbed area is $1,716.00. The $650.00
per acre for re -seeding sites of less than 1 acre was quoted to us by the City of
Fort Collins Stormwater Utility personnel.
iii The erosion control deposit for Lots 5 & 6, Block 5, Replat (No. 1) of
Evergreen Park will be $1,716.00. This deposit is refundable.
VI. VARIANCE REQUEST:
A. Variance from City of Fort Collins requirements
1. With this report, the developer is formally requesting the following variances from:
a. the requirement that one (1') foot of freeboard be provided,
b. the requirement that a foot and a half (1.5') of vertical separation between the
100-year water surface elevation and the proposed finished floor of the buildings
be provided. We are requesting that the minimum separation be reduced to one
half of a foot (0.5'),
c. the requirement that the maximum depth of water in a parking lot be less than
one (1') foot. We are requesting that the maximum depth be increased to one and a
half (1.5') feet.
PAGE 10
Final Drainage and Erosion Control Report
Lots 5 & 6, Block 5; Replat (No. 1) of Evergreen Park
VI. VARIANCE REQUEST:
A. Variance from City of Fort Collins requirements (continued)
2. The. constraints on the grading caused by the site topography and the ADA
requirements do not allow us to provide the required freeboard.
3. The detention requirements within the Evergreen - Greenbriar basin and the
topography of the site do not allow us to meet the separation or maximum depth
requirements.
VIL CONCLUSIONS:
A. Compliance with Standards
1. All drainage analysis has been performed according to the requirements of the City
of Fort Collins Storm Drainage Criteria Manual and the City of Fort Collins policy.
2. All Erosion Control design complies with the City of Fort Collins Erosion Control
Reference Manual and generally accepted practices.
B. Drainage Concept
1. The drainage design for Lots 5 and 6, Block 5, Replat (No: 1) of Evergreen Park is
in accordance with the City of Fort Collins requirements, except as noted in the
variance requests, and the recommendations of the Amended Greenbriar/Evergreen
Master Drainage Plan.
2. There will be no adverse downstream effects due to the development of the site.
VIM REFERENCES:
1. Fort Collins Storm Drainage Criteria Manual
2. Urban Drainage and Flood Control District Drainage Criteria Manual
3 Greenbriar-Evergreen Park Master Drainage Plan; Engineering Professionals
4. A draft of the Amended Greenbriar-Evergreen Basin Master Drainage Plan;
Lidstone & Anderson, Inc.; Project No COTST05.4; dated September 6, 1994
APPENDIX I
Storm Drainage Calculations
PLOW SUMMARY FOR LOT 5 & 6 EVERGREEN PARK
DESIGN CONTRIBUTING AREA C2 C10 C100 Tc Tc I2 I10 I300 Q2 Q10 Q100 DESIGN
POINT SUB 2,10 100
BASINS) ac. min. min iph iph iph cfe cfe cfe
+rrrrrrrrrr+++rrrrrre+++rrrrrrrrr+++rrrrttrrrr+rrrrrrrttrrrrrrrtrrrrrrrrrrrttrr++++r+r++rrrrrtrrttrr++
A Iw & Ie4 1.33 0.20 0.20 0.25 35.50 33.50 1.31 2.36 3.93 0.35 0.63 1.31 HISTORIC
GBWDPOND Ie3 0.43 0.91 0.91 1.00 10.00 10.00 2.54 4.45 7.14 1.00 1.75 3.070 REL. RATE
ABBREVIATIONS
GBWDPOND=GRBENBRIAR WEST REGIONAL DETENTION POND
SHEAR ENGINEERING CORPORATION
COMPOSITE RUNOFF COEFFICIENT FOR
SUB BASIN Iw
PAGE 1
PROTECT :LOT 5 AND 6 EVERGREEN PARK
PROJ.NO. :1498-01-95 DATE: 11/22/95
LOCATION :EVERGREEN PARK BY: MHO
FILE :PISHCOEB
NOTES :PHASE 1 ON SITE ONLY
RUNOFF
SURFACE CORP.
CHARACTERISTICS AREA C C*A
(acres)
STREETS
ASPHALT 0.355 0.950 0.337
CONCRETE 0.010 0.950 0.010
GRAVEL 0.000 0.500 0.000
ROOFS 0.275 0.950 0.261
LAWNS SANDY SOIL
FLAT < 2% 0.000 0.100 0.000
AVERAGE 2 - 7% 0.000 0.150 0.000
STEEP > 7% 0.000 0.200 0.000
LAWNS HEAVY SOIL
PLAT < 2% 0.180 0.200 0.036
AVERAGE 2 - 7% 0.000 0.250 0.000
STEEP > 7% 0.000 0.350 0.000
TOTAL AREA 0.820 0.644
C2 CIO C100
COMPOSITE C VALUE 0.785 0.785 0.982
USE 0.79 0.79 0.98
HISTORIC C VALUE 0.20 0.20 0.25
THE 1/2 ROW AREA = 0.18 ACRES
COMPOSITE C VALUE C2 CIO C100
0.86 0.86, 1.00
TOTAL AREA = 1.00 ACRES
SUMMARY FOR SUB BASINS Iw & Irow
HISTORIC
COMPOSITE C VALUE C2 CIO C100
0.32 0.32 0.39
DEVELOPED
COMPOSITE C VALUE C2 CIO C100
0.80 0.80 0.98
SHEAR ENGINEERING CORPORATION
COMPOSITE RUNOFF COEFFICIENT FOR
SUB BASIN Is
PAGE 2
PROJECT :LOT 5 AND 6 EVERGREEN PARK
PROJ.NO. :1498-01-95 DATE: 10/22/95
LOCATION :EVERGREEN PARK - BY: MHO
FILE :FISHCOEF
NOTES :PHASE 2 ON SITE ONLY
RUNOFF
SURFACE COEF.
CHARACTERISTICS AREA C C*A
(acres)
STREETS
ASPHALT 0.272 0.950 0.258
CONCRETE 0.020 0.950 0.019
GRAVEL 0.000 0.500 0.000
ROOFS 0.598 0.950 0.568
LAWNS SANDY SOIL
FLAT < 2% 0.000 0.100 0.000
AVERAGE 2 - 7% 0.000 0.150 0.000
STEEP > 7% 0.000 0.200 0.000
LAWNS HEAVY SOIL
FLAT < 2% 0.050 0.200 0.010
AVERAGE 2 - 7% 0.000 0.250 0.000
STHHP > 7% 0.000 0.350 0.000
TOTAL AREA 0.940 0.856
C2 C10 C100
COMPOSITE C VALUE 0.910 0.910 1.000
USE 0.83 0.83 1.00
SHEAR ENGINEERING CORPORATION
PAGE 3 DETENTION VOLUME REQUIRED FOR
WEST DETENTION POND OF LOT 5 & 6 EVERGREEN PARK
PROTECT: PHASE 1 OF LOT 5 & 6 EVERGREEN PARK DATE: 11/22/9S
PROJ.NO. 1498-01-95
FILE: PISHCUHP BY MHO
NOTE: 1/2 ROW INCLUDED IN AREA
CUMULATIVE RUNOFF METHOD
FOR
SIZING DETENTION PONDS
DESIGN STORM: 100 YEAR RUNOFF COEFFICIENT 1.00
RELEASE RATE: 0.71 CPS AREA: 1.00 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 rrr+r++r+r+rr+r+rrrrxt+rrrrrrrrrrrrrr rrrrrr+r+++trt+ttrrtrrrrrrrrrrrrrx
5 300 9.30 9.30 2790.0 213.0 2577.0 0.06
10 600 7.14 7.14 4284.0 426.0 3858.0 0.09
15 900 6.06 6.06 5454.0 639.0 4815.0 0.11
20 1200 5.21 5.21 6252.0 852.0 5400.0 0.12
25 1500 4.63 4.63 6945.0 1065.0 5880.0 0.13
30 1800 4.20 4.20 7560.0 1278.0 6282.0 0.14
35 2100 3.81 3.81 8001.0 1491.0 6510.0 0.15
40 2400 3.60 3.60 8640.0 1704.0 6936.0 0.16
45 2700 3.28 3.28 8856.0 1917.0 6939.0 0.16
50 30003.02 3.02 9060.0 2130.0 6930.0 0.16
55 3300 2.80 2.80 9240.0 2343.0 6897.0 0.16
60 3600 2.60 2.60 9360.0 2556.0 6804.0 0.16
65 3900 2.43 2.43 9477.0 2769.0 6708.0 0.15
70 4200 2.30 2.30 9660.0 2982.0 6678.0 0.15
75 4500 2.17 2.17 9765.0 3195.0 6570.0 0.15
80 4800 2.07 2.07 9936.0 3408.0 6528.0 0.15
rrrrr++r+rr+rrrrr+xr+rrrrrrrrrrr+rr++rr+rrrxttt++++rt+rrr+rr++r+rr+rr+r+
DETENTION VOLUME REQUIRED = 6939.00 cf
DETENTION VOLUME REQUIRED = 0.16 ac-ft
NOTE: RELEASE RATE BASED ON AREA OF 1.51 ACRES & 0.47 CFS/ACRE.
THE AREA INCLUDES THE 1/2 ROW AND ALL OF THE SITE SITUATED IN
BASIN 4 AS DELINEATED IN THE AMENDED EVERGREEN - GREENBRIAR
DRAINAGE REPORT
CONTRIBUTING AREA CONSISTS OF SUBBASINS Iw AND Irow ONLY
SHEAR ENGINEERING CORPORATION
DEVELOPED
PAGE 4 FLOW TO REGIONAL DETENTION POND
PROJECT: LOT 5 & 6 EVERGREEN PARK DATE 11/24/95
FILE: FISHRAT PROJ. NO.1498-01-95
NOTES: BY MEO
AREA (A)= 0.430 ACRES CONTRIBUTES FLOW TO REGIONAL DETENTION POND
ONSITB AREA IN BASIN 3B OF EVERGREEN GREENBRIAR DRAINAGE REPORT
RUNOFF COEF. (C)
2 YEAR 10 YEAR 100 YEAR
C = 0.91 0.91 1.00
ASSUME 95/5 IMPERVIOUS/PERVIOUS
TIME OF CONCENTRATION (Tc)
OVERLAND TRAVEL TIME (Ti) NOT APPLICABLE
LENGTH =NA FEET
SLOPE =NA
4
2 YEAR
10 YEAR
100 YEAR
C = 0.20
0.20
0.25
Ti (min)= 0.00
0.00
0.00
NOT APPLICABLE
TRAVEL TIME (Tt)=L/(60*V) FLOW TYPE
L (ft) _? S (})
_? ?
V (fps)
_?
Tt(min)=
0.00
L (ft) _? S (})
_? ?
V (fps)
_?
Tt(min)=
0.00
L (ft) _? S (})
_? ?
V (fps)
_?
Tt(min)=
0.00
L (ft) _? S (})
_? ?
V (fps)
_?
Tt(min)=
0.00
L (ft) _? S (})
_? ?
V (fps)
_?
Tt(min)=
0.00
L (ft) _? S (})
_? ?
V (fps)
_?
Tt(min)=
0.00
L (ft) _? S (})
_? ?
.V (fps)
_?
Tt(min)=
0.00
NOTE: ALL VELOCITIES TAKEN FROM FIGURE 3-2
TOTAL TRAVEL TIME
(min) =
0.00
Tc =Ti+TOTAL TRAVEL TIME
ASSUME = 10 MINUTES DUE TO
SIZE OF
AREA AND TO BE CONSERVATIVE
2 YEAR
10 YEAR
100 YEAR
Tc (min)= 0.00
0.00
0.00
USE Tc = 10
10
10
INTENSITY (I) (iph)
2 YEAR
10 YEAR
100 YEAR
I = 2.54
4.45
7.14
NOTE: INTENSITIES TAKEN FROM FIGURE
3-1
RUNOFF (Q= CIA) (cfs)
2 YEAR
10 YEAR
100 YEAR
Q = 1.00
1.75
3.07
CONCLUDE:USE QIOO AS RELEASE RATE FROM EAST DETENTION POND
SHEAR ENGINEERING CORPORATION
PAGE 5 DETENTION VOLUME REQUIRED FOR
BAST DETENTION POND OF LOT 5 & 6 EVERGREEN PARK
PROJECT: PHASE 2 OF LOT 5 & 6 EVERGREEN PARK DATE: 11/22/95
PROJ.NO. 1498-01-95
FILE: FISHCUHP BY MBO
NOTE: EASTERN PORTION OF SITE
CUMULATIVE RUNOFF METHOD
FOR
SIZING DETENTION PONDS
DESIGN STORM: 100 YEAR RUNOFF COEFFICIENT 1.00
RELEASE RATE: 3.07 CPS AREA: 0.94 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
rrrr+r++r+++r+++w++r+wrwwxwwxwwwwwwwxrwwwwwrwwwxwrwwwrxwrwxwxwx rxxrxxrx+
5 300 9.30 8.74 2622.6 921.0 1701.6 0.04
10 600 7.14 6.71 .4027.0 1842.0 2185.0 0.05
15 900 6.06 5.70 5126.8 2763.0 2363.8 0.05
20 1200 5.21 4.90 5876.9 3684.0 2192.9 0.05
25 1500 4.63 4.35 6528.3 4605.0 1923.3 0.04
30 1800 4.20 3.95 7106!4 5526.0 1580.4 0.04
35 2100 3.81 3.58 7520.9 6447.0 1073.9 0.02
40 2400 3.60 3.38 8121.6 7368.0 753.6 0.02
45 2700 3.28 3.08 8324.6 8289.0 35.6 0.00
w rwwxwwrwxwxxrwxxxxrxxrxxrrxrrxrxrrrrrrrwrrrrxrrrwwwrwwwrrxrwrwrwxwwxwwx
DETENTION VOLUME RRQUIRBD = 2363.76 cf
DETENTION VOLUME REQUIRED = 0.05 ac-ft
NOTE: RELEASE RATE BASED ON DEVELOPED 100-YEAR FLOW FROM PORTION OF
SUBBASIN Iw LOCATED BASIN 3B AS DELINEATED IN THE EVERGREEN
GREENBRIAR DRAINAGE REPORT. REFER TO PAGE 4
CONTRIBUTING AREA CONSISTS OF SUBBASIN Ie ONLY
SHEAR ENGINEERING CORPORATION
AVERAGE END AREA METHOD
FOR WEST DETENTION POND
VOLUMES
PAGE 6
PROJECT :LOTS 5 & 6 EVERGREEN PARK DATE: 11/22/95
PROD. NO:1498-01-95
LOCATION:BLUE SPRUCE DRIVE BY MRO
NOTES :PHASE 1 POND FILE: PISHAVG
CONSTANT: 64 - 1 SQ IN. FIRST EVEN CONTOUR 68.6 FEET
INVERT 68.33 FEET TOP ELEV 69.62 FEET
INCREMENT 0.2 FOOT SCALE: 1" = 30 FEET
rrrrtrxr +t+*rrrr rrft++++ rtrrrrrr rtrtxr+! r+r*rrrr rxt+x**+ trrrrr!! ****rrrr
STAGE BLEV PLANI- AREA AREA VOLUME CUM. CUM. CUM.
METER, (Al) (A2) (V1) VOLUME VOLUME VOLUME
ft ft READING aq in sq ft cf cf cy ac-ft
t rrtf lff ft**trrt fl+lf+*f ttrrlxtR +lkf t**t tklT!!!! f!****r• t!!!!!f* *trlrVf!
0.00 68.33 0 0.00 0 0 0 0 0.00
0.27 68.60 68.5 1.07 963 130 130 5 0.00
0.47 68.80 167 2.61 2348 331 461 17 0.01
0.67 69.00 430.5 6.73 6054 840 1301 48 0.03
0.87 69.20 637 9.95 8958 1501 2803 104 0.06
1.07 69.40 780 12.19 10969 1993 4795 178 0.11
1.27 69.60 899 14.05 12642 2361 7156 265 0.16
1.49 69.82 1017 15.89 14302 2964 10120 375 0.23
FORMULAE:A1= (PLANIMETER READING)/CONSTANT
A2= (A1)*SCALE SQUARED
VOLUME REQUIRED WITH 1/2 ROW = 6939 CF
WATER SURFACE ELEVATION REQUIRED = 69.58 FEET
FINISHED FLOOR ELEVATION = 70.5 FEET
SEPARATION PROVIDED = 0.92 FEET REQUEST VARIANCE BECAUSE < 1.5 FRET
MAXIMUM WATER DEPTH = 1.25 FEET REQUEST VARIANCE BECAUSE > 1.0 FOOT
PREBBOARD PROVIDED = 0.24 FRET REQUEST VARIANCE BECAUSE < 1.0 FOOT
CONCLUDE:SET OVERFLOW HEIGHT AT 69.58
POND WILL BE ADEQUATE
w J1�vi"
u
n Vp N Q.
0
tTA
SHEAR ENGINEERING CORPORATION
AVERAGE END AREA METHOD
FOR EAST DETENTION POND
VOLUMES
PAGE 7
PROTECT :LOTS 5 & 6 EVERGREEN PARK DATE: 11/22/95
PROT. NO:1498-01-95
LOCATION:BLUS SPRUCE DRIVE BY MHO
NOTES :PHASE 2 POND FILE: FISHAVG
CONSTANT: 64 = 1 SO IN. FIRST EVEN CONTOUR 68 FEET
INVERT 67.8 FEET TOP ELRV 69.82 FEET
INCREMENT 0.5 FOOT SCALE: 1" = 30 FEET
####tlxt ####lfff xt##tltt f4f##!#! tft#x### tftfttkx #ltttttx #tltf4Rk t!tltftf
STAGE ELEV PLANI- AREA AREA VOLUME CUM. CUM. CUM•
METER (Al) (A2) (V1) VOLUME VOLUME VOLUME
ft ft READING sq in eq ft cf cf cy ac-ft
t rrrrr++ +rrrrt++ frf rf rr+ #+f rf x+r ++lf xrxx ###tlffx ♦#+##!fr ###+#!tr fxx#++l+
0.00 67.80 0 0.00 0 0 0 0 0.00
0.20 68.00 10 0.16 141 14 14 1 0.00
0.70 68.50 88 1.38 1238 345 359 13 0.01
1.20 69.00 247 3.86 3473 1178 1536 57 0.04
1.70 69.50 578 9.03 8128 2900 4437 164 0.10
2.02 69.82 727 11.36 10223 2936 7373 273 0.17
FORMULAE:A1= (PLANIMETER READING)/CONSTANT
A2= (A1)*SCALE SQUARED
VOLUME REQUIRED = 2363 CF
WATER SURFACE ELEVATION REQUIRED =
69.14 PEST
FINISHED FLOOR ELEVATION =
70.00
FEET
SEPARATION PROVIDED -
0.86
FEET REQUEST VARIANCE
BECAUSE <
1.5 FEET
MAXIMUM WATER DEPTH = -
1.34
FEET REQUEST VARIANCE
BECAUSE >
1.0 FEET
PREEBOARD PROVIDED =
0.68
FEET REQUEST VARIANCE
BECAUSE <
1.0 FOOT
CONCLUDS:SBT OVERFLOW HEIGHT AT 69.30
POND WILL BE ADEQUATE
FA
SHEAR ENGINEERING CORPORATION
i
PAGE 8
SOUTH PARKING LOT OUTLET STRUCTURE
PROJECT: LOT 5 & 6 EVERGREEN PARK DATE: 11/22/95
PROJECT NO 1498-01-95 BY MEO
PROJECT LOCATION :BLUE SPRUCE DRIVE
FORT COLLINS
FILE NAME: FISHOUT
INPUT FOR OUTLET STRUCTURE
STRUCTURE TYPE:
?
WEIR TYPE
BROADCRESTED
LOWER ORIFICE DIAM.
(ft)
=
0.25 WEIR LENGTH
(ft)
= 2.00
LOWER ORIFICE INV.
(ft)
=
68.33 WEIR INVERT
(ft)
= 69.Sa
LOWER ORIFICE COEF.
(Cl)
=
0.65 WEIR CORP.
(Cw)
= 2.60
UPPER ORIFICE DIAM.(ft)
= NA
TOP OF BERM
(ft)
= 69.82
UPPER ORIFICE INV.
(ft)
= NA
INIT. DELTA
(ft)
= 0.27
UPPER ORIFICE CORP.
(Cu)
= NA
DELTA HEAD
(ft)
= 0.20
2 YR. RELEASE RATE
(cfe)
= NA
10 YR RELEASE RATE
(cfa)
= NA
10 YR WSBL
REQUIRED (ft)
_ ?
100 YR RELEASE RATE
(cfe)=
0.36 100 YR WSEL
REQUIRED (ft)= 69.58
OUTLET PIPE DIAM. (ft)
= NA
OVER FLOW
YES
PIPE SLOPE (%)
= NA
WEIR TYPE
BROADCRESTED
MANNINGS n
= NA
WHIR LENGTH
(ft)
= 230.00
WEIR INVERT
(ft)
= 69.82
WEIR COEF.
(CWO)
= 2.60
NOTE: THE HUNDRED YEAR RELEASE RATE IS FOR PHASE 1 ONLY
****r*** rx*rr*rr ******** *OUTPUT* *****x** *****t** ******** ********
PIPE AREA (SF) = 0.00 WETTED PERIMETER = 0.00 FRET
HYD. RAD (FT) = 0.000 FEET R^2/3 = 0.0000
OUTLET PIPE CAPACITY = 0.00 CPS
LOWER ORIFICE AREA (A) = 0.0491 SQUARE 'FEET
UPPER ORIFICE AREA (A) = 0.0000 SQUARE FEET
****+rr +x*r++* *tr**r* *OUTPUT* *+r*xtt r**rr+x r****+* xtx**** t***rr* +xtt*xr rrttx** *******
OVERFLOW SPILLWAY
r*rr*rr +*xr*r* rttrr** *rtrxrr
HEAD HEAD HEAD SUB HEAD
ELEV. OVER LOWER OVER .UPPER OVER WEIR TOTAL OVER WEIR TOTAL ELEV.
LOWER ORIFICE UPPER ORIFICE WEIR PLOW FLOW WEIR FLOW FLOW
ORIFICE FLOW ORIFICE FLOW
ft ft cfa ft cfa ft cfa cfa ft cfa cfa ft
68 33 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 68.33
68.60 0.27 0.13 0.00 0.00 0.00 0.00 0.13 0.00 0.00 0.13 68.60
68.80 0.47 0.18 0.00 0.00 0.00 0.00 0.18 0.00 0.00 0.18 68.80
69.00 0.67 0.21 0.00 0.00 0.00 0.00 0.21 0.00 0.00- 0.21 69.00
69.20 0.87 0.24 0.00 0.00 0.00 0.00 0.24 0.00 0.00 0.24 69.20
69.40 1.07 0.26 0.00 0.00 0.00 0.00 0.26 0.00 0.00 0.26 69.40
69.60 1.27 0.29 0.00 0.00 0.02 0.01 0.30 0.00 0.00 0.32 69.60
69.80 1.47 0.31 0.00 0.00 0.22 0.54 0.85 0.00 0.00 1.07 69.80
69.82 1.49 0.31 0.00 0.00 0.24 0.61 0.92 0.00 0.00 1.16 69.82
69.58 1.25 0.29 0.00 0.00 0.00 0.00 0.29 0.00 0.00 0.29 69.5E
69.635 1.31 0.29 0.00 0.00 0.06 0.07 0.36 0.00 0.00 0.41 69.64
ORIFICE EQUATION: CA(29H)''1/2 WEIR FLOW EQTN. : CwLH^3/2
1 SHEAR ENGINEERING CORPORATION
PAGE 9
NORTH PARKING LOT OUTLET STRUCTURE
PROJECT: LOT 5 & 6 EVERGREEN PARK DATE: 11/22/95
PROTECT NO 1498-01-95 BY MEO
PROTECT LOCATION :BLUE SPRUCE DRIVE
FORT COLLINS
FILE NAME: FISHOUT
INPUT FOR OUTLET STRUCTURE
STRUCTURE TYPE: ?
LOWER ORIFICE DIAM. (ft) =
LOWER ORIFICE INV. (ft) =
LOWER ORIFICE COEF. (Cl) =
UPPER ORIFICE DIAM.(£t) = ?
UPPER ORIFICE INV. (ft) = ?
UPPER ORIFICE COEF. (CU) = ?
2 YR. RELEASE RATE (cfs) = MA
10 YR RELEASE RATE (cfs) = NA
100 YR RELEASE RATS (cfs)=
OUTLET PIPE DIAM. (ft) = NA
PIPE SLOPE (t) = NA
MANNINGS n = NA
WEIR TYPE BROADCRESTED
0.25 WEIR LENGTH (ft) = 2.00
68.71 WEIR INVERT (ft) - 69.58
0.65 WEIR COEF. (CW) = 2.60
TOP OF BERM (ft) - 69.82
INIT. DELTA (ft) = 0.09
DELTA HEAD (ft) = 0.20
10 YR WSEL REQUIRED (ft) = ?
0.35 100 YR WSBL REQUIRED (ft)= 69.58
OVER FLOW
WEIR TYPE
WEIR LENGTH (ft) =
WHIR INVERT (ft) =
WEIR COEF. (Cwo) =
rrr+++rr ***r***r rx*+rrr+ *OUTPUT* *rxr**rr *******t ******•* ********
PIPE AREA (SF) = 0.00 WETTED PERIMETER = 0.00 FEET
HYD. RAD (FT) = 0.000 FEET R-2/3 = 0.0000
OUTLET PIPE CAPACITY = 0.00 CPS
LOWER ORIFICE AREA (A) = 0.0491 SQUARE FEET
UPPER ORIFICE AREA (A) = 0.0000 SQUARE FRET
**+**** ******* ******* *OUTPUT* **r**** t****** *r+r+x+ x+++++r *+*tr+r rxr+rrr *+r*rr* rrrrrrr
OVERFLOW SPILLWAY
**+*rrr r+*+r++ *rr*rxr rrr+rrr
HEAD HEAD HEAD SUB HEAD
ELEV. OVER LOWER OVER UPPER OVER WEIR TOTAL OVER WEIR TOTAL ELEV.
LOWER ORIFICE UPPER ORIFICE WEIR PLOW FLOW WEIR FLOW FLOW
ORIFICE FLOW ORIFICE FLOW
ft ft cfs ft cfs ft cfs cfs ft cfs cfs ft
68.71 0.00 0.00 0.00 0.00 . 0.00 0.00 0.00 0.00 0.00 0.00 68.71
68.80 0.09 0.08 0.00 0.00 0.00 0.00 0.08 0.00 0.00 0.08 68.80
69.00 0.29 0.14 0.00 0.00 0.00 0.00 0.14 0.00 0.00 0.14 69.00
69.20 0.49 0.18 0.00 0.00 0.00 0.00 0.18 0.00 0.00 0.18 69.20
69.40 0.69 0.21 0.00 0.00 0.00 0.00 0.21 0.00 0.00 0.21 69.40
69.60 0.89 0.24 0.00 0.00 0.02 0.01 0.26 0.00 0.00 0.28 69.60
69.80 1.09 0.27 0.00 0.00 0.22 0.54 0.80 0.00 0.00 1.02 69.80
69.82 1.11 0.27 0.00 0.00 0.24 0.61 0.88 0.00 0.00 -1.12 69.82
69.58 0.87 0.24 0.00 0.00 0.00 0.00 0.24 0.00 0.00 0.24 69.58
69.652 0.94 0.25 0.00 0.00 0.07 0.10 0.35 0.00 0.00 0.42 69.65
r+rrr+++ r+rr*r*r rrrrr*rx trrrx+++ +r+++r+r *rrr*rt* r*r*r*+r xr+++++* +r+rrrrr rrxrrr+r rrrrrrrr r++xrrrr
ORIFICE EQUATION: CA(2gH)^1/2 WEIR FLOW EQTN. : CwLHA3/2
TOTAL RELEASE RATE FROM SITE AT 100 YEAR W.S.ELEV. = 0.53 < 0.71
SHEAR ENGINEERING CORPORATION
PAGE 10
BAST DETENTION POND OUTLET STRUCTURE
PROJECT: LOT 5 & 6 EVERGREEN PARK DATE: 11/22/95
PROJECT NO 1498-01-95 BY MBO
PROJECT LOCATION :BLUE SPRUCE DRIVE
PORT COLLINS
FILE NAME: FISHOUT
INPUT FOR OUTLET STRUCTURE
STRUCTURE TYPE: ? WEIR TYPE ?
LOWER ORIFICE DIAM. (ft) = 0.60 WEIR LENGTH (ft) =NA
LOWER ORIFICE INV. (ft) = 64.80 WHIR INVERT (ft) =NA
LOWER ORIFICE CORP. (Cl) = 0.65 WEIR COEF. (Cw) = 2.60
UPPER ORIFICE DIAM.(ft) _ ? TOP OF BERM (ft) = 69.82
UPPER ORIFICE INV. (ft) _ ? INIT. DELTA (ft) = 3.00
UPPER ORIFICE CORP. (Cu) _ ? DELTA HEAD (ft) = 0.50
2 YR. RELEASE RATE (cfe) = NA
10 YR RELEASE RATE (cfe) = NA 10 YR WSBL REQUIRED (ft) _ ?
100 YR RELEASE RATE (cfs)= 3.07 100 YR WSBL REQUIRED (ft)= 69.14
OUTLET PIPE DIAM. (ft) = NA OVER FLOW _ YES
PIPE SLOPE (%) = NA WHIR TYPE BROADCRESTED
MANNINGS n = NA WEIR LENGTH (ft) = 15.00
WEIR INVERT (£t) = 69.30
WEIR COEH. (Cwo) = 2.60
NOTE: THE HUNDRED YEAR RELEASE RATE IS FOR PHASE 1 ONLY
r•+++++r xtxtxrr+ r+r+++++ *OUTPUT* r++rr+xt xrrxr+++ ++++x+xt rr+++++x
PIPE AREA (SF) = 0.00 WETTED PERIMETER = 0.00 FEET
HYD. RAD (FT) = 0.000 PRHT R^2/3 = 0.0000
OUTLET PIPE CAPACITY = 0.00 CPS
LOWER ORIFICE AREA (A) = 0.2827 SQUARE FEET
UPPER ORIFICE AREA (A) = 0.0000 SQUARE FEET
+++t t+x xr+rrr: +xrtrrr *OUTPUT* rt++++r trtttxr r+xr++t rxrr+r+ ttrrr+r +ttxrxr rrxrxrr rr+rrr♦
OVERFLOW SPILLWAY
rrr+r++ xxr+rrr rxrxr++ ++rrxrr
HEAD HEAD HEAD SUB HEAD
ELHV. OVER LOWER OVER UPPER OVER WEIR TOTAL OVER WEIR TOTAL ELEV.
LOWER ORIFICE UPPER ORIFICE WEIR FLOW FLOW WEIR FLOW FLOW
ORIFICE FLOW ORIFICE PLOW -
ft ft cfe ft cfe ft cfe cfe ft cfe cfs ft
64.80 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 64.80
67.80 3.00 2.SS 0.00 0.00 0.00 0.00 2.55 0.00 0.00 2.55 67.80
68.30 3.50 2.76 0.00 0.00 0.00 0.00 2.76 0.00 0.00 2.76 68.30
68.80 4.00 2.95 0.00 0.00 0.00 0.00 2.95 0.00 0.00 2.95 68.80
69.30 4.50 3.13 0.00 0.00 0.00 0.00 3.13 0.00 0.00 3.13 69.30
69.80 5.00 3.30 0.00 0.00 0.00 0.00 3.30 0.00 0.00 3.30 69.80
69.82 5.02 3.30 0.00 0.00 0.00 0.00 3.30 0.00 0.00 3.30 69.82
69.14 4.34 3.07 0.00 0.00 0.00 0.00 3.07 0.00 0.00 3.07 69.14
t xrr+rrr +txrrrr+ +r++t ttt rrr++r+t txrrrrrt ttxxrxrr rrr+xxxx rxrrrx+r ttxrrrr+ rtx+x+rx rrttr+r+ +xxx+♦rr
ORIFICE EQUATION: CA(2gH)^1/2 WHIR FLOW EQTN. : CwLHA3/2
SHEAR ENGINEERING CORPORATION
HISTORIC
PAGE 11 FLOW FROM PHASE 1 TO BLUE SPRUCE DRIVE
PROJECT: LOT 5 6 6 EVERGREEN PARK DATE 11/22/95
FILE: PISHRAT PROJ. NO.1498-01-95
NOTES: BY HBO
AREA (A)= 1.330 ACRES CONTRIBUTES FLOW TO BLUE SPRUCE DRIVE
ONSITE AREA IN BASIN 4 OF EVERGREEN GREBNBRIAR DRAINAGE REPORT
RUNOFF CORP. (C)
2 YEAR 10 YEAR 100 YEAR
C = 0.20 0.20 0.25
SEE SPREAD SHEET ATTACHED ON PAGE 1
TIME OF CONCENTRATION (TO
OVERLAND TRAVEL TIME (Ti)
LENGTH = 280 FEET SLOPE = 0.50 $
2 YEAR 10 YEAR 100 YEAR
C = 0.20 0.20 0.25
Ti (min)= 35.40 35.40 33.43
NOT APPLICABLE FOR HISTORIC CONDITIONS
TRAVEL TIME (Tt)=L/(60*V) FLOW TYPE
L (ft) _? S ($) _? ?
L (ft) _? S ($) _? ?
L (ft) _? S ($) _? ?
L (ft) _? S ($) _? ?
L (ft) _? S ($) _? ?
L (ft) _? S ($) _? ?
L (ft) _? S ($) _? ?
NOTE: ALL VELOCITIES TAKEN FROM FIGURE 3-2,
Tc =Ti+TOTAL TRAVEL TIME
2 YEAR 10 YEAR 100 YEAR
Tc (min)= 35.40 35.40 33.43
USE Tc = 35.5 35.5 33.5
INTENSITY (I) (iph)
2 YEAR 10 YEAR 100 YEAR
1 = 1.31 2.36 3.93
NOTE: INTENSITIES TAKEN FROM FIGURE 3-1
RUNOFF (Q= CIA) (cfs)
2 YEAR 10 YEAR 100 YEAR
Q = 0.35 0.63 1.31
CONCLUDE:FOR REFERENCE ONLY
V (fps)
_?
Tt(min)=
0.00
V (fps)
_?
Tt(min)=
0.00
V (fps)
_?
Tt(min)=
0.00
V (fps)
_?
Tt(min)=
0.00
V (fps)
_?
Tt(min)=
0.00
V (fps)
_?
Tt(min)=
0.00
V (fps)
_?
Tt(min)=
0.00
TOTAL TRAVEL TIME
(min) =
0.00
No Text
APPENDIX II
Erosion Control Calculations
Erosion Control Sequencing schedule
Erosion Control security deposit estimates
No Text
RAINFALL PERFORMANCE STANDARD EVALUATION
PROJECT: -} S 4 6 13l0,k CUcrS`ec� P -k STANDARD FORM A
COMPLETED BY: DATE: IQ 131 5
DEVELOPED
ERODIBILITY
Asb
Lsb
Ssb
Lb
Sb
PS
SUBBAgIN
ZONE
(ac)
(ft)
M
(feet)
M
M
Zou
�Z_u
Zoo
�
x=`�Z32
30U
1Z •�r
-1
MARCH 1991 8-14 DESIGN CRITERIA
EFFECTIVENESS CALCULATIONS
PROJECT: ��i �} t311Z ew-ry STANDARD FORM B
COMPLETED BY: DATE: U13 5�
Erosion Control C-Factor P-Factor
Method. Value Value Comment
YZvv<�i. Usou N X 1+J U '\ O g-S
A3"�7�=.`/.=o sore d',o\ I•:o 4`-i �i n.:.
S v T N GL '
1.1j
01%
Sad - o .0 Ito
MAJOR
PS
SUB
AREA
BASIN
M
BASIN
(Ac)
CALCULATIONS
�2.3Z
=W
MARCH 1991 8-15 DESIGN CRITERIA
CONST.SEQ.
F-Client/Fisher/Erosion/Const.Seq
1498-02-95
Date:10/11/95
CONSTRUCTION SEQUENCE
Phase 1 only
PROJECT: LOT 5 AND 6 BLOCK 5 EVERGREEN PARK
STANDARD FORM C
SEQUENCE FOR 19 96 ONLY COMPLETED BY:MEO/Shear Engineering Corp.
Indicate 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 196
Month J F M
OVERLOT GRADING
WIND EROSION CONTROL
* Soil Roughening
Perimeter Barrier
Additional Barriers
Vegetative Methods
Soil Sealant
Other
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
***
***
A M J J A S O N D
STRUCTURES: INSTALLED BY: OWNER MAINTAINED BY: OWNER
VEGETATION/MULCHING CONTRACTOR: OWNER
DATE PREPARED: 1011I 95 DATE SUBMITTED: 10 12 95
APPROVED BY THE CITY OF FORT COLLINS ON:
November 27, 1995
Project No: 1498-01-95
Basil Hamdan
City of Fort Collins Stormwater Utility
P.O. Box 580
Ft. Collins, Colorado 80522
Re: Lots 5 & 6, Block 5, Replat (No. 1) of Evergreen Park
Fort Collins, Colorado
Dear Basil,
Attached is the erosion control security deposit estimate for Lots 5 & 6, Block 5, Replat (No. 1)
of Evergreen Park.
ESTIMATE 1:
320 LF of Silt Fence Q $ 3.00 per LF $ 960.00
1 - Gravel Inlet Filter @ $75.00 each $ 75.00
TOTAL ESTIMATED COST: $ 1,035.00
x 1.50
S 1,552.50
ESTIMATE 2:
re -vegetate the disturbed area of 1.00 acre at $650.00 per acre $1,144.00
TOTAL ESTIMATED COST: $ 1,144.00
x 1.50
S 1,716.00
In no instance shall the amount of the security be less than $1,000.00. Therefore, the total
required erosion control security deposit for Lots 5 & 6, Block 5, Replat (No. 1) of Evergreen
Park will be $1,716.00.
If you have any questions, please call at 226-5334.
Sincerely
Brian W. Shear, P.E.
Shear Engineering Corporation
BWS / meo
cc: Greg Fisher
Dave Stringer, City of Fort Collins
4836 S. College, Suite 12 Ft. Collins, CO 80525 (970) 226-5334 FAX (970) 282-031 1
November 27, 1995
Project No: 1498-01-95
Re: EROSION CONTROL SECURITY DEPOSIT REQUIREMENTS:
Lots 5 & 6, Block - 5, Replat (No. 1) of Evergreen Park
Fort Collins, Colorado
A. An erosion control security deposit is required in accordance with City of Fort Collins
policy (Chapter 7, Section C: SECURrIY; page 7.23 of the City of Fort Collins
Development Manual). In no instance shall the amount of the security be less than
$1000.00.
1. According to current City of Fort Collins policy, the erosion control security deposit
is figured based on the larger amount of 1.5 times the estimated cost of installing
the approved erosion control measures or 1.5 times the cost to re -vegetate the
anticipated area to be disturbed by construction activity.
i The cost to install the proposed erosion control measures is approximately
$1,035.00. Refer to the cost estimate attached in Appendix I. 1.5 tunes the cost
to install the erosion control measures is $ 1,552.50.
ii. Based on current data provided by the City of Fort Collins Stormwater Utility,
and based on an actual anticipated net affected area which will be disturbed by
construction activity (approximately 1.76 acres), we estimate that the cost to re -
vegetate the disturbed area will be $1,144.00 ($650.00 per acre x 1.76 acres).
1.5 times the cost to re -vegetate the disturbed area is $1,716.00. The $650.00
per acre for re -seeding sites of less than 1 acre was quoted to us by the City of
Fort Collins Stormwater Utility staff.
CONCLUSION:
The erosion control security deposit amount required for Lots 5 & 6, Block 5, Replat (No.
1) of Evergreen Park will be $1,716.00.
4836 S. College, Suite 12 Ft. Collins, CO 80525 (970)'226-5334 FAX (970) 282-0311
APPENDIX III
Backup Diagrams and Exhibits
Table 3-3; Rational Method Runoff Coefficients for Composite Analysis
Table 3-4; Rational Method Frequency Adjustment Factors
Figure 3-2; Estimate of Average Flow Velocity for Use with the Rational Formula
Figure 3-1; City of Ft. Collins Rainfall Intensity Duration Curve
R-M-P Medium Density Planned Residential District — designation for medium density
areas planned as a unit (PUD) to provide a variation in use and building placements
with a minimum lot area of 6,000 square feet.
R-L-M Low Density Multiple Family District — areas containing low density multiple family
units or for one -family orther use in two family dwellings lings strict andth a9 000 square feet forminimum lot area of 00square multiple -family
dwellings.
M-L Low Density Mobile Home District — designation for areas for mobile home parks
containing independent mobile homes not exceeding 6 units per acre.
M-M Medium Density Mobile Home District — designation for areas of mobile home
parks containing independent mobile homes not exceeding 12 units per acre.
B-G General Business District — district designation for downtown business areas,
including a variety of permitted uses, with minimum lot areas equal to 1 /2 of the total
floor area of the building.
B-P Planned Business District designates areas planned as unit developments to
provide business services.while protecting the surrounding residential areas with
minumum lot areas the same as R-M.
H-B
wiith a minimuusiness mstrict � m lot area equalto 112 ofthe total floorea of automobile-orientated
a area of the building.busi-
nesses
B-L Limited Business District — designates areas for neighborhood convenience
centers, including a variety of community uses with minimum lot areas equal to two
times the total floor area of the building.
C Commercial District —designates areas of commercial, service and storage areas.
I-L Limited Industrial District —designates areas of light industrial uses with a minimum
area of lot equal to two times the total floor area of the building not to be less than
20,000 square feet
I-P Industrial Park District —designates light industrial park areas containing controlled
industrial uses with minimum lot areas equal to two times the total floor area of the
building not to be less than 20,000 square feet.
1-G General Industrial District — designates areas of major industrial development.
T Transition District — designates areas which are in a transitional stage with regard
to ultimate development.
For current and more explicit definitions of land uses and zoning classifications, refer to the
Code of the City of Fort Collins, Chapters 99 and 118.
Table 3-3
RATIONAL METHOD RUNOFF COEFFICIENTS FOR COMPOSITE ANALYSIS
Runoff Coefficient
Character of Surface
Streets, Parking Lots, Drives:
0.95
Asphalt..................................................................................
0.95
Concrete .....................................................
........................................
.........................
0. 50
Gravel................................................... .....................
0. 95
Roofs .........................................................................................
.................
Lawns, Sandy Soil:
0.1
Flat <2%
5
................
Average 2 to 7% .................................................................
0.20
Steep >7% ....................................................... ...................................
Lawns, Heavy Soil:
0.20
Flat<2%............................................................................................. 0.25
Average 2 to 7%.........................................:........................................ 0.35
Steep >7%................................................
.........:................................
MAY 1984
3-4 DESIGN CRITERIA
3.1.7 Time of Concentration
In order to use the Rainfall Intensity Duration Curve, the time of concentration must be
known. This can be determined either by the following equation or the "Overland Time of
Flow Curves" from the Urban Storm Drainage Criteria Manual, included in this report (See
Figure 3-2).
Tc=1.87 (1.1 —CC,) D1t2
—Sr/3
Where Tc =Time of Concentration, minutes
S =Slope of Basin, %
C = Rational Method Runoff Coefficient
D = Length of Basin, feet
CI = Frequency Adjustment Factor
Time of concentration calculations should reflect channel and storm sewer velocities as well
as overland flow times.
3.1.8 Adjustment for Infrequent Storms
The preceding variables are based on the initial storm, that is, the two to ten year storms. For
storms with higher intensities an adjustment of the runoff coefficient is required because of
the lessening amount of infiltration, depression retention, and other losses that have a
proportionally smaller effect on storm runoff.
These frequency adjustment factors are found in Table 3-4.
Table 3-4
RATIONAL METHOD FREQUENCY ADJUSTMENT FACTORS
Storrs Return Period Frequency Factor
(years) C,
2 to—, 0 1.00
11 to25 1.10
26 to 50 1.20
51 to 100 1.25
Note: The product of C times C, shall not exceed 1.00
3.2 Analysis Methodology_
The methods presented in this section will be instituted for use in the determination and/or verification
of runoff at specific design points in the drainage system. These methods are (1), the Rational Method
and (2) the Colorado Urban Hydrograph Procedure (CUHP). Other computer methods. such as
SWMM; STORM, and HEC-1• are allowable if results are not radically different than these two. Where
applicable, drainage systems proposed for construction should provide the minimum protection as
determined by the methodology so mentioned above.
3.2.1 Rational Method
For drainage basins of 200 acres or less, the runoff may be calculated by the Rational
Method, which is essentially the following equation:
Q = CICIA
Where Q = Flow Quantity, cfs
A = Total Area of Basin, acres
CI = Storm Frequency Adjustment Factor (See Section 3.1.8)
C = Runoff Coefficient (See Section 3.1.6)
1 = Rainfall Intensity, inches per hour (See Section 3.1.4)
3.2.2 Colorado Urban Hydrograph Procedure
For basins larger than 200 acres, the design storm runoff should be analyzed by deriving
synthetic unit hydrographs. It is recommended that the Colorado Urban Hydrograph
Procedure be used for such ana!ysis. This procedure is detailed in the Urban Storm Drainage
Criteria Manual, Volume 1, Section 4.
MAY 1984 3-5 DESIGN CRITERIA
DRAINAGE CRITERIA MANUAL
RUNOFF
50
30
F- 20
z
w
0
D:
w
0. 10
z
w
a
0 5
W
CO 3
0
U 2
M
W
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2 .3 .5 1 2 3 5 10 20
VELOCITY IN FEET PER SECOND
FIGURE 3-2. ESTIMATE OF AVERAGE FLOW VELOCITY FOR
USE WITH THE RATIONAL FORMULA.
*MOST FREQUENTLY OCCURRING"UNDEVELOPED"
LAND SURFACES IN THE DENVER REGION.
REFERENCE: "Urban Hydrology For Small Watersheds" Technical
Release No. 55, USDA, SCS Jan. 1975.
5 -1-84
URBAN DRAINAGE & FLOOD CONTROL DISTRICT
No Text
APPENDIX IV
Stuffer Envelope
Grading, Drainage and Erosion Control Plan
Easement dedication exhibit for Lots 5 and 6, Block 5
EASEMENT
F-ctient/ Fisher/ Drainage/ EASEMENT
EASEMENT DEDICATION
Project No: 1498-01-95
Date: 11/27/95
Revised: 12/12/95
KNOW ALL MEN BY THESE PRESENTS: That the undersigned being the owner of record of
Lots 5 & 6, Block 5, Replat (No. 1) of Evergreen Park, City of Fort Collins, County of
Latimer, State of Colorado, as recorded in Latimer County records at Book 1157, Page 0128,
Reception Number 85405, do hereby dedicate and convey to the City of Fort Collins for public
use forever hereafter a drainage easement described as follows:
Beginning at the Northwest corner of Lot 5, Block 5, Replat (No. 1) of Evergreen Park, said
point being on the Blue Spruce Drive Right -of -Way line and being the TRUE POINT OF
BEGINNING_ of this description.
Thence continuing along the north property line of said Lot 5, North 90°00'00" East, 301.25
feet; thence leaving said north property line and continuing South 00°00'00" East, 50.50 feet;
thence North 90000'00" East, 65.75 feet; Thence South 00°00'00" East 49.50 feet; Thence North
90000'00" West, 367.00 feet to a point along the Blue Spruce Drive Right -of -Way; North
00000'00" East, 100.00 feet to the TRUE POE -IT OF BEGINNING.
Excluding the following area;
Beginning at the Northwest corner of Lot 5, Block 5, Replat (No. 1) of Evergreen Park, said
point being on the Blue Spruce Drive Right -of -Way line; Thence continuing along the north
property line of said Lot 5, North 90°00'00" East, 79.00 feet; thence leaving said north property
line and continuing South 00°00'00" East, 10.25 feet to the POINT OF BEGINNING of this
description.
Thence North 90°00'00" East, 200.25 feet; Thence South 00000'00" East 60.25 feet; Thence
North 90000,001, West, 200.25 feet; Thence North 00°00'00" East, 60.25 feet to the POINT OF
BEGINNING.
Beginning at the Southwest corner of Lot 6, Block 5, Replat (No. 1) of Evergreen Park, said
point being on the Blue Spruce Drive Right -of -Way line and being the TRUE POINT OF
BEGINNING of this description.
Thence continuing along the south property line of said Lot 5, North 90000'00" East, 301.25
feet; thence leaving said south property line and continuing North 00°00'00" East, 50.50 feet;
thence North 90°00'00" East, 65.75 feet; Thence North 00°00'00" East 49.50 feet; Thence North
90000'00" West, 367.00 feet to a point along the Blue Spruce Drive Right -of -Way; South
00000100" East, 100.00 feet to the TRUE POINT OF BEGINNING.
Excluding the following area;
Beginning at the Southwest corner of Lot 6, Block 5, Replat (No. 1) of Evergreen Park, said
point being on the Blue Spruce Drive Right -of -Way line; Thence continuing along the south
property line of said Lot 6, North 90°00'00" East, 79.00 feet; thence leaving said south property
line and continuing North 00°00'00" East, 10.25 feet to the POINT OF BEGINNING of this
description.
Thence North 90°00'00" East, 200.25 feet; Thence North 00000'00" East 60.25 feet; Thence
North 90°00'00" West, 200.25 feet; Thence South 00000'00" East, 60.25 feet to the POINT OF
BEGINNING.
I
EASEn[ENr
F-client/ Fisher/ Drainage/ EASEMENT
Project No: 1498-01-95
Date: 11/27/95
Revised: 12/12/95
It is understood by the undersigned that, by acceptance of this dedication, the City of Fort Collins
does not have the duty to maintain the easement.
Witness our hands and seals this day of
Owner of record of Lots 5 & 6, Block 5, Replat (No.1) of Evergreen Park
STATE OF COLORADO )
)SS
COUNTY OF LARHSAER )
The foregoing instrument was acknowledged before me this day of
19 , by
Owner of record of Lots 5 & 6, Block 5, Replat (No. 1) of Evergreen Park
Witness my hand and official seal.
My Commission Expires:
Notary Public
ATTORNEY'S CERTIFICATE
This is to certify that on the day of , A.D. 19 , I examined the
title to the property hereon described and established that the owners and proprietors of record of
said property as construed in C.R.S. 1973, 31-23-111, are as shown hereon as of said date.
Signature:
Registration
Address: