HomeMy WebLinkAboutTHE COTTAGES AT MIRAMONT PUD, PHASE IV - FINAL - 54-87AD - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTFinal Drainage and Erosion Control Report
for
THE COTTAGES AT MIRAMONT P.U.D.
Fort Collins, Colorado
Prepared for:
ALBRECHT HOMES
4836 South College Avenue Suite 10
Fort Collins, Colorado 80525
date* ,
Prepared by:
SHEAR ENGINEERING CORPORATION
Project No: 1410-01-94
DATE: April, 1995
4836 S. College, Suite 12 Fort Collins, CO 80525 (303)226-5334
PLAT OF
THE COTTAGES AT MIRAMONT P.U.D.
LOCATED IN SECTION 1. TOWNSHIP S NORTH, RANGE 69 VEST OF -THE
.STH PX. CITY OF FORT COLLINS. COUNTY OF LARIIIER, STATE, OF COLORADO
i-W or
o
rm
RRAMRAMM
tl
IORf C flw+Tv
OP WIOOT.
•dp'
9'RO'00••.
.
$
YRIARmMT IIIImRAMO TeOO OBRIBR EIJYBBm.BIR ORYO.071m1f:
— —
c 9
r fw 1
n..rmr
M
•'100T R • a
TRACT 'A' crow
..AID<O
O1IMERSXP aRmp
Ci..Imrt
R A 00 �
1dn
Mwaoa mw.aa .n. mal.ee
ILW
wl.
� .
so so 7.
...,
ek
8a
7 bR
8 rg
8
4 (°
3
,8
2
1
am
I
W
I
• �`.. <ur a ....•. r n�M. w..aM
wm"®iO"e— ssaa�
N�.
$
W.
! •"I
as ssl$4aw
YI$�aM
Y.I
.�. all V.I
SANY.
g.u.
.'as if. 9
I t
w.... K,. �M.e�...
iE
�-
=
4R
ii
[
.o
. 9e '$
p
:9
Lau••
M nMMwe MOM.wM` .u<nmo oMM < M �d w
w.e•n a w�M a wa>,ee w a n,r
a
I
U p
?
RP
TRACT 'A'
IA was
i
Ro" ,
$
$
VICIMMY MAP
ATTaMns cxmrlun
10 b�
11
$
13 $l
14
Y
b
1
I
�.....�.wK..
iiT a�u+a F-u..4 r[wnwm.Mu,ao-nwm
it
^I
.112
aA Y.pa.
M,
.115
1$R
^
Y.
p». Y.^^ae1
Y18
.
ITDM MD AS: MACCM NM, NO OPAO"t
MEMM. 34
;••�
•mae
® V /C=,W. MaL IWMIDXnC[ AIM UMM CI%Mff
.¢Mraew a
COUMAPM Al IR MIM
I
som m Run
I
.rrw.p w MM vwMM"•M )� Pw.M w M Mn I•n w•a
wonee a ei _ •• n`.
.TRACT
.
A = Q.!S
C•
Xrs
t•
Gi
Av
r TRACT 'A' t•:Iasr
• M TM :I= waf N • WKSTMt
wnMM n w w.. w x w<a w MM.mMM r-aa w IiM
eaw w as b w n_
TRUE POINT
OF
BEOINNINOL
/ 7B /
TNL COTTAGES
AT MIRAMONT:P.U:O..37
w
OWRR3= ATTTslusose
3a aeam IaaoS tRAct ,�
I , A
/ yg��I
t I ..00MrdI
satin. I, TSI, u.M
1 IdwDN.RpM w:
1twnNM�Uw�sCrnM.d M.
susvtTORs aRDTICAn
•
1p.<v tom, IIM.A IMIO Ma.��P�MM w<
JS
/ /
1
,RAM
6 M"G"dl wa ai arttW w�.i m� a7'•,"g�y"i,*0"
7� \ �1
1
7�waa CvlwMau�r
M Mw s<.r we mei.M1y0*oo. s ' M
m Imy�ua�olgmNwoWro(pnas 7 r / ��•`13 •, i1i1i1
MIMw �MIK nMS NiU Y011' i
\PoM
I
ROaOIM M,+
wor. ue vOM. M.
IM p TMa
SLMp'[Y K 6bi101aD II�D[ id nTARs nia�na� an
tar•
0/ 1M[C[RMICA]ICM 41OaM 1OIpOM.
ITR.
�t +sn.
M_ .. O1°P"
e� "" I•" R^ M'4 ^'
INTERMILL LAND SURVEYING
TOOPUT
._ rw
-a—.w.
Iti.sr aMlr
'.>r r •'m'
ALBRECHT HOURSImI
M. Cla'I[uMR pMuy-w.swq caoMAm ARw
THE COTTAGES AT MIRAMONT P.U.D.
.w+�•I
'='36 uI-0i1
FORT COUIM. COLORADO
PAGE 1
The Cottages at Miramont P.U.D.
Final. Drainage and Erosion Control Report
INTRODUCTION:
The Cottages at Miramont P.U.D. is contained within an area considered with the Amended
Oak/Cottonwood Farm Overall Drainage Study. More specifically, this is the area which
contributes storm water runoff to Detention Pond #313 as defined in the Amended
Oak/Cottonwood Farm Overall Drainage Study. Although this report has been specifically
prepared for the Cottages at Miramont P.U.D., several known proposed projects, adjacent
to this one, are considered with this report because of the direct relationship to the projects,
all of which contribute to detention pond #313 which will be detailed with final design
parameters in this report. The projects considered and referenced in this report include:
Oak Hill Apartments P.U.D.
* Miramont Fitness and Tennis Center
* The Courtyards at Miramont P.U.D., Second Filing
* The Courtyards at Miramont P.U.D., First Filing
The Oak Hill Apartments P.U.D. Final Drainage and Erosion Control Report has been by
RBD Inc:, Consulting Engineers. Final conclusions which relate to the Oak Hill
Apartments P.U.D. have been closely coordinated with RBD, Inc. and included in this
report. Reference to conclusions presented with the Final Drainage and Erosion Control
Report .for the Oak Hill Apartments P.U.D. will be clearly identified in this report when
referenced.
The Final Drainage and Erosion Control Report for Miramont Fitness and Tennis Center
was submitted on September, 1994 and was approved by the City of Fort Collins Storm
Water Utility.. The report was prepared by Water, Waste & Land, Inc. Final conclusions
which relate to the Miramont Fitness and Tennis Center have been closely coordinated with
Water, Waste & Land, Inc. and included in this report. Reference to conclusions presented
with the Final Drainage and Erosion Control Report for Miramont Fitness and Tennis
Center will be clearly identified in. this report when referenced.
The Courtyards at Miramont P.U.D. First and Second Filing has been approved by the City
of Fort Collins and are currently under construction. Final conclusions which relate to the
The Courtyards at Miramont P.U.D. First and Second Filing are based primarily on the
approved reports and design.
The Amended Oak/Cottonwood Farm Overall Drainage Study is being prepared by RBD Inc.,
Consulting Engineers simultaneously with this proposal. The Amended Oak/Cottonwood Farm
Overall Drainage :Study is the primary reference for the storm water management design for
Courtyards at Miramont P.U.D., Second Filing. Reference to conclusions presented with the
Amended Oak/Cottonwood Farm Overall Drainage Study will be clearly identified in this report
when referenced.
PAGE 2
The Cottages at Miramont P.U.D.
Final Drainage and Erosion Control Report
L GENERAL LOCATION. AND DESCRIPTION:
A. Location
1. The Cottages at Miramont P.U.D. is located in the East One Half (1/2) of Section 1,
Township 6 North, Range 69 West of the 6th P.M., City of Fort Collins, County of
Latimer,- State of Colorado.
2. More specifically, The Cottages at 1Vliramont P.U.D. is located on the east side of
Boardwalk Drive, approximately three quarters (3/4) of a mile South of Harmony
Road. The project is east of the Upper Meadow at Miramont and west of the
Collinwood assisted living facility (Oakridge West P.U.D. First Filing).
3. The Cottages at Miramont P.U.D. is bounded on the west by Oak Hill Apartments
P.U.D._, on the north by Miramont Fitness and Tennis Center on the east by
Oakridge West P.U.D. First Filing, and on the south .by The Courtyards at
Miramont P.U.D., Second Filing
B. Description of Property
1. The 2.23 acres site (The Cottages at Miramont. P.U.D.) is currently vacant land
covered with native vegetation.
2. Development of the property will consist of the construction of sixteen (16) single
family residences and the infrastructure to service them.
3. The site will be accessed from the extension of Rule Drive from Lemay Avenue.
H. DRAINAGE BASINS AND SUB -BASINS:
A. Major Basin Description
1. The Cottages at Miramont P.U.D. is located in the McClelland -Mail Creek
Drainage Basin as delineated on the City of Fort Collins Storm Water Basin Map.
a. The Basin fee rate for this basin is $3,717.00 per gross acre according to the
development fee section of the City of Fort Collins Development Manual.
b. Our understanding is that the above mentioned fees may be reduced with the
provision for detention. Detention has been provided for this site with the
Miramont Overall Drainage Plan (ODP). Refer to following discussion in the
Sub -Basin description section: The amount of impervious area created by the
development may also affect Basin fees.
PAGE 3
The Cottages at Miramont P.U.D.
Final Drainage and Erosion Control Report
H. DRAINAGE BASINS AND SUB -BASINS:
B. Sub -Basin Description
1. The Cottages at Miramont P.U.D. is contained within Basin 208 of the Amended
Oak/Cottonwood Farm Overall Drainage Plan (ODP).
2. There is a detention pond identified in the Amended Oak/Cottonwood Farm Overall
Drainage Plan located downstream of the Cottages at Miramont P.U.D. project
which was defined for all projects within Basin 208 of the ODP including Cottages
at Miramont P.U.D.
a. The pond is designated as pond #313 of the Amended Oak/Cottonwood Farm
Overall Drainage Study.
b. This pond is located within the limits of Tract D of the Courtyards at Miramont
P.U.D., Second Filing, a plat recorded in Larimer County records. Tract D and
the detention pond is currently owned by Oak Farm, Inc., A Colorado
Corporation.
c. The existing detention pond was originally designed by RBD, Inc. in association
with the Upper Meadow at Miramont, Second Filing. The pond was
constructed based on the original Oak/Cottonwood Farm Overall Drainage
Study. It was constructed with additional volume requirements for irrigation
purposes. It was constructed in association with the Upper Meadow at
Miramont, Second Filing.
d. Preliminary Pond volume requirements and water surface elevation data were
provided on the Utility Plan titled "Detention Pond and Erosion Control Plan"
for Upper Meadow at Miramont P.U.D., Second Filing, prepared by RBD,
Inc., dated June 7, 1993, RBD Project No.. 504-003.
e. Amendments to the Oak/Cottonwood Farm Overall Drainage Study during the
design phase of the Courtyards at Miramont P.U.D., Second Filing, indicated a
need for additional volume than was originally identified. The additional
volume was provided during earthwork operations for Phase 1 construction of
the Courtyards at Miramont P.U.D., Second Filing.
3. All stormwater from the projects which contribute to detention pond #313, are
conveyed to the existing irrigation/detention pond. Coordination of the drainage
design for the Fitness and Tennis Center, Oak Hill Apartments, the Cottages at
Mimmont P.U.D. and the Courtyards at Miramont P.U.D., have been well
coordinated to allow the conveyance of storm water from these projects to detention
pond #313 according to the requirements of the Amended Oak/Cottonwood Farm
Overall Drainage Study.
® PAGE 4
The Cottages at Miramont P.U.D.
Final Drainage and Erosion Control Report
H. DRAINAGE BASINS AND SUB -BASINS:
B. Sub -Basin Description
4. Our understanding from the review of the drainage reports available, is that
allowable storm water release rates are very strictly controlled in this area.
a. The Amended Oak/Cottonwood Farm Overall Drainage Study indicates that
maximum allowable release rates for this area are as follows:
* 0.20 cfs/acre for the 10-year storm
* 0.50 cfs/acre for the 100-year storm,
The total required detention volumes, as well as the allowable release rate for
detention pond #313, have been summarized and are presented in subsequent
sections of this report, as well as on the Drainage and Erosion Control Plan located
in Appendix III (stuffier envelope) of this report. These summaries are consistent
with the final conclusions presented in the Amended Oak/Cottonwood Farm
Overall Drainage Study and the Final Drainage and Erosion Control Study for Oak
Hill Apartments P.U.D.
® 5. Some offsite flows will be conveyed through the site from the Miramont Tennis and
Fitness Center. This subbasin is designated as sub -basin OS-1 on the Drainage and
Erosion Control plan. Subbasin OS-1 contains approximately 0.13 acres.
6. The majority of the site (Sub -basin Ia) contributes stormwater to a low point located
in the southeast portion of the site. Sub -basin Ia contains approximately 2.0 acres.
7. The remainder of the site (approximately 0.23 acres of grassed area) contributes
stormwater directly to Courtyards at Miramont Second Filing.
III DRAINAGE DESIGN CRnERIA:
A. Regulations
1. Design Criteria from the City of Fort Collins Drainage Criteria Manual were
utilized in the design and preparation of the Drainage and Erosion Control Plan.
2. Supplemental drainage design criteria specified in the Amended Oak/Cottonwood
Farm Overall Drainage Study was also utilized.
3. Erosion control measures and design conform to the requirements of the City of
Fort. Collins Erosion Control Reference Manual.
® PAGE 5
The Cottages at Miramont P.U.D.
Final Drainage and Erosion Control Report
III DRAINAGE DESIGN CFJaERIA:
B. Development Criteria Reference and Constraints
1. The following drainage reports were considered in the final drainage design and
calculations for The Cottages at Miramont P.U.D.:
a. Oak/Cottonwood Farm Overall Drainage Study; RBD, Inc.; dated May 4, 1992;
RBD Project No: 504-001.
b. Amended Oak/Cottonwood Farm Overall Drainage Study; RBD, Inc.; dated
August 16, 1994; RBD Project No: 504-001.
c. Preliminary Drainage Report for Oak Hill Apartments P.U.D.; RBD, Inc.; dated
February 7, 1994; RBD Project No: 088-010.
d. Final Drainage and Erosion Control Report for Oak Hill Apartments P.U.D.;
RBD, Inc.; dated May, 1994; RBD Project No: 088-010.
e. Preliminary Drainage and Erosion Control Report for Courtyards at Miramont
® P.U.D. (Phases I-V) and The Cottages at Miramont P.U.D.. (Phase VI); Shear
Engineering Corporation; Project No: 1410-01-94; Dated. March, 1994.
f. Final Drainage and Erosion Control Report for Miramont Fitness and Tennis
Center; Water, Waste and Land; dated September 12, 1994, WWI. Project No:
402.
g. Master Drainage Study for the Oakridge Business Park.
h. Drainage and Erosion Control Report for Oakridge West P.U.D. First Filing.
i. The final Drainage and Erosion Control Report for Courtyards at Miramont
Second Filing; Shear Engineering Corporation; Project No: 1410-01-94; Dated
October, 1994.
2. The property to the north, Miramont Fitness and Tennis Center. has received Final
Approval. Therefore, grading along the northern property line of the Cottages At
Miratont will match the proposed contours of the Miramont Fitness and Tennis
Center.
3. The property to the south, Courtyards at Miramont Second Filing, is currently
under construction. Grading along the southern property line of the Cottages at
`Miramont will match the proposed contours of Courtyards at Miramont Second
Filing.
® 4. The property to the west, Oak Hill Apartments P.U.D., is currently under review.
Grading along the western property line of the Cottages at Miramont will match the
proposed contours of Oak Hill Apartments P.U.D.
® PAGE 6
The Cottages at Miramont P.U.D.
Final Drainage and Erosion Control Report
III DRAINAGE DESIGN CRITERIA:
B. Development Criteria Reference and Constraints (continued)
5. The property to the east, Collinwood (Oakridge West P.U.D. Fast Filing), is
developed and limits the amount of grading that can be performed along the eastern
property line of the Cottages at Miramont P.U.D.
C. Hydrological Criteria
1. The Rainfall -Intensity -Duration curves for the City of Fort Collins were used
(Figure 3.3.1-1, attached in Appendix II for reference), in conjunction with the
"Rational Method" for determining peak flows at various concentration points.
D. Hydraulic Criteria
1. Street capacity references provided in the City of Fort Collins Drainage Criteria
Manual and street capacity exhibits which were prepared by this office, based on
the Mannings equation, were utilized.
2. Drainage channel capacities are based on the Mannings Equation. The Mannings
coefficients are as suggested by City of Fort Collins Drainage Criteria Manual.
IV DRAINAGE FACILITY DESIGN:
A. General Concept
1. Stormwater runoff from the site will be conveyed to the southeast corner of the
property via a combination of :
a. Overland flow.
b. Gutter flow.
2. No detention will be provided on the site as the Cottages at Miramont will
contribute stormwater to the regional pond (Pond 313) located just south of the
project in Tract D of the Courtyards at Miramont Second Filing. Pond 313 is sized
for contributions from the Cottages At Miramont P.U.D. along the other projects
mentioned in the introduction of this report.
3. No storm sewer is provided on the site as the outlet device located at concentration
point A has more than enough capacity to handle the peak flows to concentration
point A.
L�
PAGE 7
The Cottages at Miramont P.U.D.
Final Drainage and Erosion Control Report
W DRAINAGE FACILITY DESIGN:
B. Specific Details:
1. Specific design details and final design calculations have been provided with this
submittal of the Final Drainage and Erosion Control Report and Utility Plans for the
Cottages at Miramont P.U.D..
2. The existing irrigation/detention pond, which will service the Courtyards and
Cottages at Miramont P.U.D., the Oak Hill Apartments P.U.D. and the Miramont
Fitness and Tennis Center, is identified on the Amended Oak/Cottonwood Farm
Overall Drainage Study as pond #313.
a. The pond was originally designed and constructed in conjunction with the
Upper Meadow at Miramont P.U.D., Second Filing.
i. Reference: "Detention Pond and Erosion Control Plan" for Upper Meadow
at Miramont P.U.D., Second Filing (Sheet 1 of 1) prepared by RBD, Inc.
dated June 7, 1993, Project No. 504-003..
ii. Preliminary detention pond volume requirements were based on the
original Oak/Cottonwood Farm Overall Drainage Study; RBD, Inc.; dated
May 4, 1992; RBD Project No: 504-001.
iii. Final detention pond requirements were determined based on actual
contributing design areas and are presented in the most current Amended
Oak/Cottonwood Farm Overall Drainage Study. -
b. The existing irrigation/detention pond was constructed in 1993. The plans for
the pond indicate that the pond would. first be constructed as an 'interim pond
which would be an irrigation/retention pond. The ultimate pond would act as
an irrigation/detention pond. The following represents summary data which
was presented on the "Detention Pond and Erosion Control Plan" for Upper
Meadow at Miramont. P.U.D., Second Filing (Sheet 1 of 1).
i, The interim pond is proposed to have 6.7 acre feet of irrigation volume.
I The ultimate pond is proposed to have 2.7 acre feet of irrigation volume.
iii. The ultimate pond is proposed to have 4.0 acre feet of detention volume.
c. The Amended Oak/Cottonwood Farm Overall Drainage Study indicates a 4.60
acre-foot detention requirement based on the SWMM model. Refer to the
Amended Oak/Cottonwood Farm Overall Drainage Study and the Appendix of
the Final Drainage and Erosion Control Study for the Oak Hill Apartments
P.U.D.; Sheet 10 - Site Hydrology.
• d. The existing pond detention storage volume is 4.20 acre-feet based on actual
volume verification provided by RBD, Inc. Consulting Engineers. Refer to the
Appendix of the Final Drainage and Erosion Control Study for the Oak Hill
Apartments P.U.D.; Sheet 10 - Site Hydrology.
® PAGE 8
The Cottages at Miramont P.U.D.
Final Drainage and Erosion Control Report
W DRAINAGE FACILITY DESIGN:.
B. Specific Details (continued):
2. e. Detention pond #313 required additional volume due to actual volume
requirement determination. Additional detention pond grading requirements to
provide the additional volume were shown on the Final Grading Plan , Sheet 11
of 13 of the Utility Plans for Courtyards at Miramont P.U.D., Second Filing.
The pond expansion provided 4.75 ac-ft of detention storage volume. The
detention pond design stage -storage curve is included in Appendix A of this
report for reference.
f. The detention pond will also act as an irrigation facility for this site, the open
space greenbelt areas on the west side of Boardwalk Drive, and for future
development to the south and east. A pump house and necessary infrastructure
is under construction to distribute the irrigation water as needed.
i. Construction of the pump house will not be associated with the The
Cottages at Miramont P.U.D.
® I Maintenance of the detention/irrigation pond will be the responsibility of the
owner of the tract on which the pond is located. This includes the pump
house.
3. A 4' wide curb opening will be provided at the southeast corner of the site
(Concentration Point A) to convey the stormwater runoff from the site into Tract A
of the Courtyards at Miramont P.U.D., Second Filing.
a. Tract A of the Courtyards at Miramont P.U.D. Second Filing is designated as a
Utility, Drainage, and Access easement on the final plat of Courtyards at
Miramont P.U.D., Second Filing.
b. The peak 100 year or major flow at. Concentration. Point A is 14.45 cfs. Refer to
pages 1, la, and 2 in the drainage calculations located in Appendix I.
c. The capacity of the 4' wide curb opening is 24.29 cfs. Refer to page 3 in the
drainage calculations located in Appendix I:
d. The peak 10 year or minor storm flow at Concentration .Point A is 6.64 cfs.
Refer to pages 1, la, and 2 in the drainage calculations located in Appendix I.
e. The street capacity at Concentration Point A for the minor storm is 7.29 cfs.
This is based on the capacity of the private drive up to the top of the curb on the
low side of the private drive. Refer to page 4 in the drainage calculations located
in Appendix L
11
® PAGE 9
The Cottages at Miramont P.U.D.
Final Drainage and Erosion Control Report
IV DRAINAGE FACILITY DESIGN:
B. Specific Details (continued):
2..
f The street capacity at Concentration Point A for the major storm is 11.13 cfs.
This is based on the capacity of the private drive up to the top of the curb on the
high side of the private drive. Refer to page 4 in the drainage calculations
located in Appendix I.
g. The top of the curb on the low side of the private drive should not be
overtopped as the stormwater will be releasing through the 4' curb cut located
at the low point (Concentration Point A). The capacity of the curb cut is more
than 1 1/2 times greater than the peak flow to concentration point.
4. A low flow channel along with a grassed swale will convey the stormwater through
tract A of Courtyards at Miramont P.U.D. Second Filing and into the private drive
of Courtyards at Miramont P.U.D. Second Filing.
a. The slope of the low flow channel is 1.0%. Refer to. the Final Grading plan for
® Courtyards at Miramont P.U.D. Second Filing sheet 11 included in the stuffer
envelope.
b. The peak 100 year flow at the outfall of the swale into the private drive of
Courtyards at Miramont Second Filing is 14.98 cfs. Refer to page 5 in the
drainage calculations located in Appendix I, 133 % of the peak flow is 19.92 cfs.
c. The capacity of the low flow channel and the grassed swale at the outfall of the
swale into 'the private drive of Courtyards at Miramont Second Filing is 23.70
cfs: Refer to pages 5 and 5a in the drainage calculations located in Appendix I.
Therefore, the swale is capable of handling the stormwater generated by the
development of The Cottages at Miramont P.U.D..
d. The swale extends to the rear of lots 33 - 38 in order to intercept any stormwater
which may over top the curb on the low side of the private drive of Cottages.
5. Maintenance of the open space areas within the limits of the Cottages at Miramont
P.U.D., will be the responsibility of the developer until completion of the project. A
Homeowners Association will then assume maintenance responsibilities for the
open space areas.
PAGE 10
The Cottages at Miramont P.U.D.
Final Drainage and Erosion Control Report
V. EROSION CONTROL DESIGN CRITERIA:
A. Regulations
1. Design Criteria from the City of Fort Collins Erosion Control Reference Manual
were utilized.
VI. EROSION CONTROL FACILITY DESIGN
A. General Concept:
1. The Cottages at Miramont P.U.D. lies within the Moderate Wind Erodibility Zone
per the City of Fort Collins Erodibility Zone Map.
a. According to the criteria of the City of Fort Collins Erosion Control Reference
Manual for Construction sites, the Erosion control performance standard has
been calculated and appropriate erosion control measures identified for the
control of erosion during and after construction.
2. Erosion control measures are specified on the Drainage and Erosion Control Plan
attached in Appendix IQ (stuffer envelope). These measures will. effectively reduce
the amount of soil erosion potential created during the construction of the project.
a. Maintenance of erosion control devices, both onsite and offsite, will remain the
responsibility of the developer until the subdivision is totally developed.
VL EROSION CONTROL FACILITY DESIGN:
B. Specific Details
1. Silt fence will be installed along the downstream property lines.
2. Gravel filters will be provided at the 4' curb cut.
3. A rip rap apron will be installed at the outfall from the curb cut located at the low
point.
a. The median stone size (60) is 12 inches.
b. The apron will extend to the property line.
c. The width of the apron at the property line will be 12.0 feet'.
® PAGE 11
The Cottages at Miramont P.U.D.
Final Drainage and Erosion Control Report
V11 EROSION CONTROL SECURITY DEPOSIT:
A. An erosion control security deposit is required in accordance with City of Fort Collins
policy (Chapter 7, Section C n 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.
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.
a The cost to install the proposed erosion control devices for the The Cottages at
Miramont P.U.D. is $ 2,525.00. 1.5 times this estimate is $ 3,785.00.
i. unit prices have been provided by Connell Resources.
b. Based on current data provided by the City of Fort Collins Storm Water Utility,
and based on an actual anticipated net affected disturbed area during
construction of the Cottages at Miramont P.U.D., (approximately 2.2 acres) we
.estimate that the cost to re -vegetate the disturbed area will be $1,430.00
($650.00 per acre x 2.2 acres). 1.5 times the cost to re -vegetate the disturbed
area is $2,145.00.
i. The 2.2 acres is the actual platted area of the Cottages at Miramont P.U.D.,
housing project.
ii. The $650.00 per acre for re -seeding sites of less than 10 acres was quoted
to us by the City of Fort Collins Storm Water Utility staff.
2. The erosion control security deposit amount required for this project will be
$3,787.50. See the Erosion Control Security Deposit Requirements document
located in Appendix III (stuffer envelope).
3. The erosion control security deposit is reimbursable.
VIM VARIANCE FROM CITY STANDARDS
A. Variance from City of Fort Collins requirements
1. There will be no requests for variances from Storm Drainage Design Criteria.
11
PAGE 12
The Cottages at Nfiramont P.U.D.
Final Drainage and Erosion Control Report
IX. CONCLUSIONS:
A. Compliance with Standards:
1. All drainage design and calculations conform with the criteria and requirements of
the City of Fort Collins Storm Drainage Criteria.
2. Proposed erosion control measures conform with generally accepted erosion control
measures and the City of Fort Collins Erosion Control reference manual.
B; Drainage Concept:
1. The design of the drainage infrastructure for The Cottages at Kramont P.U.D. and
the Courtyards at Miramont Second Filing P.U.D. effectively controls any increase
in storm water runoff due to the development of The Cottages at. Miramont P.U.D..
2. The erosion control measures specified will effectively reduce erosion potential
during and after construction.
11
11
PAGE 13
The Cottages at Miramont P.U.D.
Final Drainage and Erosion Control Report
VIL REFERENCES:
1. City of Fort Collins Storm Drainage Design Criteria Manual
2. Urban Drainage and Flood Control District Urban Storm Drainage Criteria
Manual.
3. City of Fort Collins Erosion Control Reference Manual; prepared by
Hydrodynamics, Inc.; dated January 1991.
4. Oak/Cottonwood Farm Overall Drainage Study; RBD, Inc.; dated May 4, 1992;
RBD Project No: 504-001
5. Amended Oa Cottonwood Farm Overall Drainage Study; RBD, Inc.; dated
August 16, 1994; RBD Project No: 504-001.
6. Final Drainage Report for Oak Hill Apartments. P.U.D.; RBD, Inc.; dated May 2,
1994; RBD Project No: 088-010.
7. Final Drainage and Erosion Control Report for Oak Hill Apartments P.U.D.;
40 RBD, Inc.; dated May, 1994; RBD Project No: 088-010.
8. Preliminary Drainage and Erosion Control Report for Courtyards at Miramont
P.U.D. (Phases I - V) and The Cottages at Miramont P.U.D. (Phase VI); Shear
Engineering Corporation; Project No: 1410-01-94; Dated: March, 1994.
9. Final Drainage and Erosion Control Report for Miramont Fitness and Tennis
Center; Water, Waste and Land; dated July 18, 1994 WWL Project No: 402.
10. "Detention Pond and Erosion Control Plan" for Upper Meadow at Miramont
P.U.D., Second Filing (Sheet .1 of 1) prepared by RBD, Inc. dated June 7, 1993,
Project No. 504-003
1.1. Master Drainage Study for the Oakridge Business Park; RBD, Inc.; dated
September, 1990.
12. Final Drainage and Erosion Control Report for Courtyards at Miramont P.U.D.,
Second Filing; Shear Engineering Corporation; Project No: 1410-01-94; Dated:
October, 1994.
1_1
C
0
APPENDIX I
Storm Drainage Calculations
Erosion Control Calculations
® FLOW SUMMARY FOR COTTAGES AT MIRAMONT
DESIGN SUB AREA C2 C10 C100 Tc Tc. I2 I10 I100 Q2 Q10 Q100 DESIGN
POINT BASIN 2,10 100
ac. min. min iph iph iph cfs cfe cfs
A Ia & OS-1 2..13 0.76 0.76 0.95 12.50 10.00 2.34 4.10 7.14 3.79 6.64 14.45 CURB CUT
C-M
E
-- -u
15
/^
_ _ -
_ -' _ _�~� _- - -
- -
>�
-------
-----'-�------'�---- -----------
eyS
------' - - -
------
_ ______u6
U h �����
�� '
___ ___
SUB -BASIN
SURFACE
CHARACTERISTICS
STREETS
ASPHALT
CONCRETE
GRAVEL
LOTS
ROOFS
LAWNS SANDY SOIL
FLAT < 2%
AVERAGE 2 - 7%
STEEP > '7%
LAWNS HEAVY SOIL
SHEAR 814GINERRING CORPORATION
COMPOSITE RUNOFF COEFFICIENT FOR
SUBBASIN OS-1
PAGE :IA
PROJECT :COTTAGES AT MIRAMONT
PROJ.NO. :1410-01-94 DATE: 04/20/95
LOCATION :RULE DRIVE BY: M80
FILE :COTAMCOF
NOTES
OS-1 SUB -BASIN Is
RUNOFF
COEF.
AREA
C
C*A
(acres)
0.100
0.950
0.095
0.000
0.950
0.000
0.000
0.500
0.000
0.000
0.950
0.000
0.000
0.100
0.000
0.000
0.150
0...000
0.000
0.200
0.000
RUNOFF
C08F.
AREA
C
C*A
(acres)
0.730
0.950
0.694
0.000
0.950
0..000
0...000
0...500
0.000
1.210
0.670
0.811
0.000
0..950
0.000
0.000
0.100
0.000
0.000
0.150
0.000
0.000
0.200
0.000
FLAT <.246
0.030
0.200
0.006
0.060
0.200
0.012
AVERAGE -
7%
0.000
0.250
0.000
0.000
0.250
0.000
STEEP > 711
0.000
0.350
0.000
0.000
0.350
0..000
TOTAL AREA
0.130
0.101
2.000
1.516
C2
C10
C100
C2
C10
C100
COMPOSITE C
VALUE
0.777
0.777
Or971
0.758
0.758
0.948
OVERALL COMPOSITE
C VALUE FOR CONTRIBUTING AREA TO CP
'A'
C =
0.7592498
C100 =
0.949061
SAY
0.76
SAY
0.95
SHEAR ENGINEERING CORPORATION
PAGE 2 FLOW TO CONCENTRATION POINT A
FROM SUBBASIN Ia & OS-1
PROJECT: COTTAGES AT MIRAMONT DATE 04/20/95
FILE: COTAMRUN PROJ. NO..1410-01-94
NOTES: BY MSO
AREA (A)= 2.130 ACRES
RUNOFF CORP. (C)
2 YEAR 10 YEAR
100 YEAR
C = 0.76 0.76
0.95
SHE SPREAD SHEET ATTACHED ON PAGE 1
TIME OF CONCENTRATION (TO
OVERLAND TRAVEL TIME (Ti)
LENGTH = 32 FEET SLOPE = 3.69
2 YEAR 10 YEAR
100 YEAR
C = 0.05 0.10
0.40
Ti (min)= 7.22 6.88
4.81
TRAVEL TIME (Tt)=L/(60*V) FLOW TYPE
L (ft) = 31 3 ($) = 0.51 GUTTER
V (fps) =
1.5
Tt(min)=
0.34
40
L (ft) = 183 S (1) = 0.5 GUTTER-
V (fps) =
1.5
Tt(min)=
2.03
L (ft) = 63 S (4) = 2.01 GUTTER
V (fps) =
2.83
Tt(min)=
0.37
L (ft) = 212 S ($) = 0.62 GUTTER,
V (fps) =
1.63
Tt(min)=
2.,17
L (ft) = 30 S ($) = 0.5 GUTTER
V (fps) =
1-5
Tt(min)=
0.33
L (ft) =? S (4) =? ?
V (fps) _?
Tt(min)=
0.00
L (ft) =.? S (1k) =? ?
V (fps) =?
Tt(min)=
O.00
NOTE: ALL VELOCITIES TAKEN FROM FIGURE 3-2
TOTAL TRAVEL TIME
(min) =
5.25
Tc=Ti4TOTAL TRAVEL TIME
2. YEAR 10 YEAR
100 YEAR
Tc (min)= 12.47 12.13
10.06
USE Tc = 12.5 12.5
10
INTENSITY (I) (iph)
2 YEAR 10 YEAR
100 YEAR
I = 2.34 4.10
7.14
NOTE.: INTENSITIES TAKEN FROM FIGURE
3-1
RUNOFF (Q= CIA) (cfs)
2 YEAR 10 YEAR
100 YEAR
Q = 3..79 6.64
14.45
CONCLUDE:SIZE CURB CUT TO HANDLE Q100 AND CONVEY OVER GRASS TO TRACT A OF COURTYARDS AT
MIRAMONT SECOND FILING
SHE PAGE 3
® CHECK STREET CAPACITY SEE PAGES 4 & 4A
6
12
13
14
16
17
W-A
1L- �.- Q.35 Slade, U,� c�fo� lw )��Z CI?-) ��� I, � G,0�7c,� ���
P"zr-. 'AR-nj BY
MN 0
DAIE
i.
I'TA G-;s
r)o
4
Se,
- L
fNe. R
'►z _� - --Cl , s�
z (.30) 7 Cloos) -- - -- ---
12
13
15
k
16
O-L .1)-Il
19
...... ....... ...
20
21
... . ..... .... ------- --
22
C ---y, Y-- S --------- - --------- ----6--------
23
24
25
2 6
s,o t��
b-sc., ,-,4L
- ----- - -------- -
2/
Wit$t,).JL rwc- lob
No Text
No Text
SHEAR ENGINEERING
CORPORATION
PAGE
SA
CHANNEL CAPACITY
PROJECT NAME:
COTTAGES AT
MIRAMONT
DATE:
04/20/95
PROJECT. NO.
1410-01-94
BY
MEO
SWALE DESCRIPTION:SWALE
IN TRACT A OF COURTYARDS AT MIRAMONT
FILE: COTCHAN
CAPACITY OF TRIANGULAR OR TRAPEZOIDAL CHANNEL
CHANNEL
CONFIGURATION: TRAPEZOIDAL
DESIGN FLOW (cfe)
14.98
CHANNEL LINING: GRASS
1.33-Q=
19.92
Da
Db
Dc
Sc
n
W
I
(ft)
----
(ft)
----
(ft)
----
(e)
----
-----
(ft)
----
(ft)
----
4.00
4.00
1.00
1.00
0.032
3.00
0.10
0..25
= LEFT BANK SLOPE
0.25
= RIGHT BANK SLOPE
DEPTH
WIDTH
AREA
PERIM
R 2/3
S..c 1/2
Q
V
®
(s.f.)
(ft)
(s.f.)
(ft)
(A/P)
(cfe)
(ft/sec)
1.00
11.00
7.00
11.25
0.73
0.10
23.70
3i39
0.90
10.20
5.94
10.42
0.69
0.10
18.96
3.19
0.80
9.40
4.96
9.60
0..64
0..-10
14.83
2.99
0.70
8.60
4.06
8.77
0.60
0.10
11.28
2.78
0.60
7.80
3.24
7.95
0.55
0.10
8.27
2:55
0_50
7.00
2.50
7.12
0.50
0.10
5.78
2.31
0.40
6.20
1.84
6_30
0.44
0.10
3.76
2.04
0.30
5.40
1.26
5.47
0.38
0.10
2.20
1.74
0.20
4.60
0.76
4.65
0.30
0.10
1.06
1c39
0.10
3.80
0.34
3.82
0.20
0.10
0.31
0.92
0.00
3.00
0.00
3.00
0.00
0.10
0.00
0.00
i
...._s_.1-�--•__—�t�-
i
I
1 ',
1
--T—�'"
..�'Y.t-r7•__f__�_i!
' �__�__i
_.-�!
i_�
_.�_'
'_
� �
1�
� L..
�
_� ! ' _V�...
t ! .,..
� -� •'®': , _ j
..L..�
I--
' ..
; ;
ii ' f
� ; I ,
i-
, �.
I ;
..!-,.I
.
I
� I
}. iN
y' .' �
,
p,►;. i.
,.»l
I
, '.;
I
i
L..� I ,
I -I_ I is !. � I
' '
I
i
(l'.:��
_
'
I
�.1_.
I
I ; !..�a_.-;
!-
I .
, -
L_1�-.16� ;;,jr'P„
� _.r. T ; u +�� -
l !
�t -; -, . ; � r- - .r
�
_ !
-
I �!.'
_.r I
-`-r-i
I
1111 i I
� ; , .
�46
I ;
M�
`a.
� !
Imo; ._ a
4- a
f
I l
, _ (
' I�_�- (-.'t'•i
; , , ; ; • . , ;
�'�
'
; _�
I
f
'-
'-��' I-'
� .1 ,
�
�
}
� \, '- ..I
� i ; E--
t l
I_
fI
-..j
}-t-
' , 1- r-' i}—.
I
-- 1-
-' -+-;
—}
i �--1
- ._ _>.
► � �_.,
1
i
�
1
- 'r�-t- ;--� --}`'
{
i}—
-
-
�-�---�----I-+-i--
i + . a ,..T. I
�. _!
.
j
L
, -
!-
,_ ;
, . ;
!_-1-
F
_
.1 i
�
.�-
. _ t 1 � -
1 .. J_ F
� �--
-�
_.�
; -t-
I--
_ -r- -; �
_.�
t.-i
•f � � .� .
V-
�
I I
.1 , 1 ,. 1. I {_.....•
__
i _
_.._
_ ..t.+
%.I_.
_-1...1_
�
_ _T _f._I
� � 1_
_ 1 t_.
�_
1
� 1 1.
1
i
{{
t
1
1
-
TT
k
I
'
I
t
l
�_"1
I
1 A i
(. f ..,
�.._�. _,
1
!._.!_.
, - , _k
, .
I
j
, i ( ,
;19V
i..
S
�
1 _..
I
I-
- t �
-
f
; T j- ,
�•- i . j
_,
....�
I
i
(
t
No Text
C
CONSTRUCTION SEQUENCE
PROJECT: THE COTTAGES AT MIRAMONT
STANDARD FORM C
SEQUENCE FOR 19 ONLY COMPLETED BYMEOLShear 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 95 96
Month A S O N D J F M A M J J A
OVERLOT GRADING
WIND EROSION CONTROL
* Soil Roughening
RAINFALL EROSION CONTROL
STRUCTURAL:
* Sediment Trap/Basin
* Inlet Filters
* Straw Barriers
* Silt Fence Barriers
0 Asphalt/Concrete Paving
VEGETATIVE:
* Permanent. Seed Planting
* Sod Installation
***
***
STRUCTURES: INSTALLED BY: OWNER MAINTAINED BY: OWNER
VEGETATION/MULCHING CONTRACTOR: OWNER
DATE PREPARED:04/21/95 DATE SUBMITTED: 04IN195
APPROVED BY THE CITY OF FORT COLLINS ON:
® April 24, 1994
Project No. 1410-01-94
0
Basil Hamdan
City of Fort Collins Storm Water Utility
P.O. Box 580
Ft. Collins, Colorado 80522
Re: The Cottages at A iramont P.U.D.; Fort Collins, Colorado
Dear Basil,
Attached is the erosion control security deposit estimate for The Cottages at Miramont P.U.D..
EST RATE 1:
700 LF of silt fence at $3.50 per LF
1 Gravel inlet Filter at $75.00 each
TOTAL ESTIMATED COST:
ESTMATE 2:
re -vegetate the disturbed area of 2.20 acres at $650.00 per acre
TOTAL ESTMATED COST:
$ 2,450.00
75.00
$ 2,525.00
x 1.50
$ 3,787:50
$ 1,430.00
$ 1,430.00
x 1.50
$ 2,145.00
The total required erosion control security deposit will be $ 3,787.50 if paid at one time.
Because of the projected phasing of the project, security deposits may be made based on
individual estimates for each phase, or phases, of construction.
If you have any questions, please call at 226-5334.
Sincerely,
Mark Oberschmidt, EIT
Shear Engineering Corporation
BWS / mo
cc: Albrecht Homes
4836 S. College, Suite 12 Fort Collins, CO 80525 (303)226-5334
RAINFALL PERFORMANCE STANDARD EVALUATION
STANDARD FORM A
PROJECT: Co���,5es �,d�irti►-�,o�
COMPLETED BY: DATE:
DEVELOPED
ERODIBILITY
Asb
Lsb
Ssb
Lb
Sb
'PS
SUBBAgIN
ZONE
(ac)
(ft)
(;)
(feet)
o
� 0 0
MARCH 1991
8-14 DESIGN CRITERIA
lu
4
r
L.
EFFECTIVENESS CALCULATIONS
PROJECT: Cc� i vE-S h��t',3aoaJl STANDARD FORM B
COMPLETED BY: M�-Q DATE:
Erosion Control C-Factor P-Factor
Method Value Value Comment
0,�
S\ Feti�v2 �, 0 0.
MAJOR
PS
SUB
AREA
BASIN
(t)
BASIN
(Ac)
CALCULATIONS
z=
6, 452�
MARCH 1991 8-15 DESIGN CRITERIA
0 0,rn000
� W 0 W ao aD
® o rnrnrnrnoOOOoo
. . . . . . . . . . .
o �t'd'sr�tntntntntntn
� aoa000aoW W W W W W
O a MMMm MMMMMMOOO
O d'��'d'�r�•�d'�rsr�rd'tntntn
cn OaocoWOWOW W W W W W W W
0 t- co co co 01 0% 01 0 0\ 0% 0% 01 01 01 Ot 01 ON M 01 01
. . . . . . . . . . . .. . . . . . . . .
o d'�d'•woV*vod'�rd'd'd'd'srsvlg*sr�rMrow
N 00 co W 00 00 00 00 00 00 00 co co 00 00 00 CO W o0 00 00
O OMd'11�tDt01C101�1�t�l�l��l��l��l�t�000000000000
. . . . • . . . . . . . . . . . . . . . . . . . . . .
p o ����erd'�srerdsr�erd��etsrso�-we owgwV
p rt W W W W W 00 W W 0o W W W OD OD CO W W W W CO COO W W W W
O co c4 m qr Ln LnLn tG t0 t0 W %0 t0 t- t- t� I- r- r- t- r- r- - co co co
p e d'. . . . . . . . . . .
a rn M. .4.41;��d'e�'�d'd'd'd'vs Itrd'srsrsrvvv
O WWWWWWWWWW0O0a�OaoOOWWWOWWWW
U
O tD O N M d' d' In In In lff �D t0 10 t0 t0 10 10 �G tG tD I� I� t� l� � l�
. . . . . . . . . . . . . . . . . . • . . . . . . . . .
t!� c0 M4sYs!'d'-'st'd'd'srd'srd'st'4l'sYst'et'sPsrs1'st'st'd'4
z 00 W 00 00 00 00 00 00 00 W 00 CO 00 00 00 CO 00 CO 00 00 00 00 00 00 CO 00
H
0 O vc11.-INMm st%wd'd'InLn Lntntnlntntntn%D%o%o%o%0%Dt-
O t- c 4 c 4 4 t'ato to vo4to 'sr*V*stet vovo -W*V* V*V* f'ed'd'erd'd'
U 0000WooCOWWWWWWWWWWWWWgoWWboaoOOWW
E+ O Ot0000�-Ir1NNc'1r1r1N1d'd'd'eYd'd'd'd'lnlntntfl�O�D
a. • • e e . • . . • • . . . . . . . . • . . • • • e • 'e
p t0 MMMsrd'vvvOrd'srd'd'srsrd'd'srd'sr-e.0v.0srd'
w 0000OD0000WW00WW000000WW00WWOD00W000000WO
c4 ,o tnNtnt.cocnoorlrie-1NNNNNMMMi'1Md'st'st'd'ow
O dP • • . • . . • • . . . • . 0 . e . . . . • e .
00W tn NMMMMMstgw.0.0 d'd'd'sr.0gwR1'd'd'st'st'sf'sf'd'd's1'
® 00O0WCOW00000000WW0000000000W00WW0D00W WWCO
oin Mtn .-1W r10'1d'tnLn%o%or-t-t-W co co Wcococna%o%Oo00o
A,' ad' NNMMMMMMMMMMMMMMMMmoms M94 V041d'd'
Hp W ooWWWWWWWWWWWWWWWWaoaoWOaoaoaocoao
Ot0tnW0e-iNMd'd'Intntnt0tpt01t)10t�1�.t�t�W W WC►C1
[a • e • • e • • • • e • • • • . • • • • • • • • • • •
to IV 4c4c4AN1MMMMMMMMMNI!' Ac4AAc4c1MMMM
00 C0 W W 00 00 W W 00 00 W 00 00 W 00 00 00 00 CO CO W 00 OD W 00 00
Uto r1r11f1t,- W00.-iNNrlMMst'd'd'd'd'lnlntn%D%0%Dt-t-
mr-1NNN.NMMMMNIMC'199c4MCIMc4.AAA mMoMo
W W W OD W W W W W 00 00 00 00 00 00 00 00 00 CO 00 00 O0 W W W W
.p O MN1000CN0riNNMMMsf'd'd's!'d' eLnlnlnLnt01010t0
(,4 . e • • • e • • • e
(Yi M 8rly-ie-1rIN44NNNNNNNNNNNNNNNNNN
W WWWWWWWW00O0000aoO000000c0OaoWWWWWW
a
In to in 0t N M st' In tD t� t� t� W W W 0► 01 01 O� 01 01 0 0 0 0 0 0
C4 C• . • • • . . • • • e . • • . • • • e • • • e • . •
t 0 0 ri rl rl ri ri t-1_ r-1 r-4 r-i ri r1. rl r1 rl .-i ri r-i N N N N N N
r- 00 W OD W W W W W 00 W W W W W 00 W W W W W W W W W W
w
e7. O sNtnOMtntDWcoa%oo0.-ir4i-irINNr4c,4m "1mm(nM
i..i • • • e • • • e • • • • • • • • • • e • e . e • . •
N 00 C11 O O O O O O O ri ri .-1 rl rl r-i rl ri rl rl ri ri '-1 ri rl e-4 r1
t- t- co 00 W W W W W 00 CO W 00 00 W CO 00 00 00 00 CO 00 00 00 00 00
to WNW 1d'lnr-t-co(s%(Ti OOrir-iririr r4.NNMMcol MM
ri t0 W W000meM0►me0101oO0o000000oCCO00
rt�nrrrr.rrrrao0oc000co W ao W W W W ao W W o0
O tOMOd't�010rINc'1Me1'sMlnlfllntntCtGtOtOl�t�tDtOtG
r1 V%Dtl-t-t-t-W00W.W00WWWWWWWWWWWWWWW
® t11 010d'10L-0000t-t-t-to%0%Dtnd'd'MMd'r
NN01101(A%0
• • •
O O e • • • • e • • • • • . • • • . •
N N N N N N N N N N N N N N N N N N N r!ri 4 H O O
g Ex-4-+00000000000000000000000000
SC9H QOOOOOOOOOOOOOOOOOO0000000
zW r-1,Nf)d'In10t�W0�OrINMd'tL1tD1�000101nO1f10tn0
Gy Wv r-itlHrirlrlrlrlrlrNNMt'7st'st'to
® Table 8B C-Factors and P-Factors for Evaluating EFF Values.
Treatment C-Factor
P-Factor
BARE SOIL
Packedand smooth........................:...:................................... 1.00
1.00
Freshlydisked .:: .................. :.................................................. 1.00
0.90
Roughirregular surface ........................... ....:...... ..................... 1.00
0.90
SEDIMENT BASIN/TRAP................................................................. 1.00
0.50n'
STRAW BALE BARRIER, GRAVEL FILTER, SAND BAG ........................ 1.00
0.80
SILTFENCE BARRIER........................................................ ......... .:.. 1:00
0.50
ASPHALT/CONCRETE PAVEMENT ................................................... 0.01
1.00
ESTABLISHED DRY LAND (NATIVE) GRASS ........................... See Fig. 8-A
1.00
SODGRASS................................................................................ 0.01
1.00
TEMPORARY VEGETATION/COVER CROPS ........... :........... ............. 0.45121
1.00
HYDRAULIC MULCH @ 2 TONS/ACRE .......................... ........ 0.10f71
1.00
SOIL SEALANT .... 0.01-0.60141
................................................................
1.00
EROSION CONTROL MATS/BLANKETS ................. ................ ........ G.. 0.10
1.00
® GRAVEL MULCH
® Mulch shall consist of gravel having a diameter of approximately
114" to 1 1/2" and applied at a rate of at least 135 tons/acre.............. 0.05
1.00
HAY OR STRAW DRY MULCH
After olantino crass seed, apply mulch at a rate of 2 tons/acre (minimum) and adequately
anchor,
tack or crimp material into the soil.
Slope M
1
to 05............................................................... ::......:.....
0.06
1.00
6
to 10 ................................................. ...............0.06
1.00
11
to 15................................................ ................ .... ....... :.
0.07
1.00
16
to 20.....::......................................................................
0.11
1.00
21
to 25........................ :............ ......,:... :................... .........
0.14
1.00
25
to 33.... .................. ,......... ,..... ................... ................ ....0.17
1.00
>33................ ..... :............. ............... 0.................... 0..
0.20
1.00
NOTE- Use of other C-Factar or P-Factor values reported in this table must be substantiated by documentation
(1) Must be constructed as the first step in overlot grading.
(2) Assumes planting by dates identified in Table 11-4, thus dry or hydraulic mulches are not required.
(3) Hydraulic mulches shall be used only between March 15 and May 15 unless irrigated.
(4) Value used must be substantiated by documentation.
MARCH 1991 8-6 DESIGN CRITERIA
11
0
APPENDIX II
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
Table 4-1 - Initial Storm - Street Runoff Encroachment
Table 4-2 - Major Storm.- Street Runoff Encroachment
R-M-P
Medium Density Planned Residential District — designation for medium density
a variation in use and building placements
areas planned as a unit (PUD) to provide
with a minimum lot area of 6,000 square feet.
® R-L-M
Low Density Multiple Family District- areas containing low density multiple family
R-L District with a minimum lot area of 6,000 square feet
units or any other use in the
for one -family or two-family dwellings and~9,000 square feet for multiple -family
M-L
dwellings.
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
homes not exceeding 12 units per acre.
parks containing independent mobile
B G
General Business District — district designation for downtown business areas,
with minimum lot areas equal to 1 /2 of the total
including a variety of permitted uses,
floor area of the building.
B-P
Planned Business District — designates areas planned as unit developments to
the surrounding residential areas with
provide business services while protecting
minumum lot areas the same as R-M.
H-B
Highway Business District — designates an area of automobile -orientated busi-
to 1/2 of the total floor area of the building.
nesses with a minimum lot area equal
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
the floor area of the building not to be less than
area of lot equal to two times total
20,000 square feet.
® I-P
Industrial Park District —designates light industrial park areas containing controlled
lot areas equal to two times the total floor area of the
industrial uses with minimum
building not to be less than 20,000 square feet.
I-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
Character of Surface Runoff Coefficient
Streets, Parking Lots, Drives: 0.95
Asphalt..::....................................................................................... ...•.
Concrete ........................................................................................... 0.95
..
Gravel....................................................................... 0.50
Roofs.......................... ................................ ......................... ........ ... 0.95
Lawns, Sandy Soil: 0.10
Flat <2%° . ........... ........
Average 2 to 7% .. ....
0.15
Steep>7% ...... . ..................: ....::............ 020
Lawns; Heavy Soil:
Flat<2% .........:....:...........................:........................:.... 0.25
. .,. ... 0.25
Average 2 to 7% . •••• ""
® Steep >7% .................... ......... .... 0;35
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=1.81(1:1 —CC,) D112
S13
Where Tc = Time of Concentration, minutes
S = Slope of Basin, %
C = Rational Method Runoff. Coefficient
D = Length of Basin, feet
Ct = 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 effecton storm runoff.
These frequency adjustment factors are found in Table 3-4.
Table 3-4
RATIONAL METHOD FREQUENCY ADJUSTMENT FACTORS
Storm Retum Period Frequency Factor
(years) C,
2_ to 10 1.10
11 to25 1.0
26 to 50 1.20
51 to100 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
aPPlicaple, drainage systems proposed for construction should provide the minimum protection as
determined by the methodology so mentioned above.
32.1 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:
a- CfCIA
Where Q = Flow Quantity, cfs
A =Total Area of Basin, acres
Gf = Storm Frequency Adjustment Factor (See Section 3.1.8)
C = Runoff Coefficient (See Section 3.1.6)
I =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 analysis. 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
1J
lu
50
30
1- 20
z
w
U
tit
a 10
z
W
a
O 5
W
cc 3
O
U 2
cc
tJ
F-
Q
1
IWAWAS%/1111VM'
FAME I
• ��milli
•/ r
��mm
ENEMMIINMN
milli
,,
®
®I�■//■II
ME%F®/I
■
MEN
00
.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
AVERAGE FLOW VELOCITY FOR USE WITH RATIONAL METHOD
FROM FIGURE 3-2
SLOPE VELOCITY (fps)
4 FOREST FALLOW SHORT BARE GRASSED PAVED/
GRASS GROUND WATERWAY GUTTER
wrr•rrrr.twwrrwt.rtttrtw:wrt*rrrtttw♦•rr*rrwttw*ttrrrrrrrrrtrttr.rc
0.5 0.19 0.33 0.50 0.70 1.11 1.50
0.6 0.19 0.36 0.54 0.75 1.22 1.61
0.7 0.20 0.38 O.se 0.82 1.33 1.72
0.8 0.22 0.41 0.62 0.85 1.41 1.80
0.9 0.23 0.44 0.66 0.92 1.51 1.88
1.0 0.24 0.46 0.70 0.98 1.58 2.00
1.50.2E 0.54 0.82 1.21 1.83 2.36
2.0 0.35 0.65 1.00 1.47 2..16 2.83
2.5 0.3E 0.73 1.12 1.58 2.39 3.10
3.0 0.43 0.80 1.26 1.72 2.61 3.40
3.5 0.46 0.85 1.37 lies 2.80 3..67
4.0 0.50 0.93 1.47 1.94 3.00 4.00
4.5 0.52 0..97 1.54 2.04 3.17 4.18
5r0 0.54 1.05 1.64 2.19 3.37 4.45
5.5
6.0
6r5
7.0
.
8.0
8.5
9.0
9.5
10.0
No Text
FORT COLLINS
RAINFALL INTENSITY CURVE DATA FOR CITY OF FORT COLLINS
FIG 3-1
INTERPRETED DECEMBER 21, 1992
BY MARK OBERSCHMIDT
SHEAR ENGINEERING CORPORATION
INTENSITIES IN RED ARE BASED ON STRAIGHT LINE INTERPOLATION BY
MARK OBERSCHMIDT ON
MARCH 9, 1995
2
5
10
25
50
100
TIME
YEAR
YEAR
YEAR
YEAR
YEAR
YEAR
rrrt++++tr+ttt+t+tt+tttt:.tttf.rt+ttrr++tr*+++•'tt++tttrrrr+tttttt
5
3.29
4.70
5.64
1.02
7.95
9.30
6
3.14
4.49
5.402
6:.716
7.63
8.868
7
2.99
4.28
5.164
6.412
7.31
8.436
8
2.84
4.07
4.926
6.108
6.99
6.004
9
2.69
3.86
4.688
5.804
6.67
7.572
10
2.54
3.65
4.45
5.50
6.35
7.14
11
2.46
3:534
4.31
5.32
6.138
6.924
12
2.36
3.416
4.17
5.14
5.926
6.708
13
2.3
3.302
4.03
4.96
5.714
6.492
14
2.22
3.186
3.89
4.7E
5.502
6.276
15
2.14
3.07
3.75
4.60
5.29
6.06
16
2.082
2.986
3.65
4.48
5.152
5.89
17
2.024
2.902
3.55
4.36
5.014
5.72
18
1.966
2.818
3.45
4.24
4.876
5..55
19
1.908
2.734
3:35
4.12
4.136
5.38
® 20
1.85
2.65
3.25
4.00
4.60
5.21
21
1.806
2.588
3.174
3.908
4.496
5.094
22
1.762
2.526
3.098
3.816
4.392
4.978
23
1.716
2.464
3.022
3.724
4.288
4.862
24
1.674
2.402
2.946
3.632
4.184
4.746
25
1.63
2.34
2-87
3.54
4.08
4.63
26
1.598
2.294
2.816
3.466
3.998
4.544
27
1.566
2.248
2.762
3.392
3.916
4.458
28
1,.534
2.202
2-708
3.318
3.834
4.372
29
1.502
2.156
2.654
3.244
3.752
4.286
30
1.47
2.11
2.60
3.17
3.67
4.20
35
1.32
1.92
2.38
2.88
3.35
3.81
40
1.20
-1..76
2..19
2.67
3.08
3.60
45
1.12
1.62
2.02
2.46
2.84
3.28
50
1.04
1.51
1.87
2.27
2.65
3.02
55
0.97
1.40
1.73
2.12
2.46
2.80
60
0.90
1.32
1.62
1.99
2.32
2.60
65
0.88
1.24
1.52
1.94
2.18
2.43
70
0.82
1.16
1.44
1.72
2.05
2.30
75
0.79
1.11
1.38
1.62
1.93
2.17
80
0.74
1.07
1.30
1.53
1.82
2.07
85
0.70
1.06
1.23
1.46
1.73
1.96
90
0.66
0.97
1.20
1.40
1.67
1.87
95
0.64
0.91
1.13
1.32
1.59
1.77
100
0.61
0.68
1.09
1.27
1.51
1.70
® 105
0.60
0.83
1.04
1..22
1..46
1.63
110
0.57
0.80
1.00
1.18
1.40
1.57
115
0.54
0:78
0.96
1.14
1.33
1.50
120
0.52
0.76
0.91
1.10
1.19
1.44
4.2.2.1 Street Encroachment
The encroachment of gutter flow on the street for the initial storm runoff shall not ex-
ceed the specifications set forth in Table 4-1. A storm drainage system shall begin
where the encroachment reaches the limits found in this table.
Table 4=1
INITIAL STORM —.STREET RUNOFF ENCROACHMENT
Street Classification Maximum Encroachment
Local (includes places, alleys. No curb -topping. t Flow may spread to
marginal access) crown of street
Collector No curb -topping. t Flow spread must
leave at least one lane width free of water
Major Arterial
No curb -topping. t Flow spread must
leave at least one-half (1 /2) of roadway
width free of water in each direction
t Where no curbing exists, encroachment shall not extend over property lines.
4.2.2.2Theoretical Capacity
Once the allowable pavement encroachment has been established, theoretical
gutter capacity shall be computed using the following revised Manning's equation
for flow in shallow triangular channels:
0=0.56ZS'"2yM
Where o = Theoretical Gutter Capacity, cfs
y = Depth of Flow at Face of Gutter, feet
n = Roughness Coefficient
S = Channel Slope, feet/feet
Z = Reciprocal of Cross Slope, feet/feet
A nomograph based on the previous equation has been developed and is included
in Figure 4-1. The graph is applicable for all gutter configurations. An "n" value of
0.016 shall be used for all calculations involving street runoff.
4.2.2.3 Allowable Gutter Flow
In order to calculate the actual flow rate allowable, the theoretical capacity shall be
multiplied by a reduction factor. These factors are determined by the curve in Figure
4-2 entitled "Reduction Factors for -Allowable Gutter Capacity". The allowable gutter
flow calculated thusly is the value to be use&in the drainage system calculations.
MAY 1984
4-2
DESIGN CRITERIA
4.2.3 Major Storms
The determination of the allowable street flow due to the major storm shall be based on the
® following criteria:
a Theoretical capacity based on allowable depth and inundated area.
e Reduced allowable flow due to velocity conditions.
4.2.3.1 Street Encroachment
Table 4-2 sets forth the allowable street inundation for the major storm runoff.
Table 4-2
MAJOR STORM — STREET RUNOFF ENCROACHMENT
Street Classlfcatlon Maximum Encroachment
•
Local (includes places, alleys,
marginal access & collector)
Arterial and Major Arterial
4.2.3.2Theoritical Capacity
Residential dwellings, public,
commercial, and industrial buildings
shall not be inundated at the ground line
unless buildings are flood proofed. The
depth of water over the crown shall not
exceed 6 inches.
Residential dwellings, public, commercial
and industrial buildings shall not be
inundated at the ground line unless
buildings are flood proofed. Depth of
water at the street crown shall not exceed
6 inches to allow operation of emergency
vehicles. The depth of water over the
gutter flowline shall not exceed 18 inches.
In some cases, the 18 inch depth over the
gutter flowline is more restrictive than the
6 inch depth over the street crown. For
these conditions, the most restrictive of
the two criteria shall govern.
Manning's equation shall be used to calculate the theoretical runoff -carrying capac-
ity based on the allowable street inundation. The equation will be as follows:
0 =1_486 R" S'"2 A
n
Where 0 = Capacity, cfs
n = Roughness Coefficient
R = Hydraulic Radius, AIP
S = Slope, feetlfeet
A = Area, feet
Appropriate'n" values can be found in Table 4-3. Any values not listed should be
located in the Geological Survey Water Supply Paper, 1849.
Table 4-3
MANNING'S ROUGHNESS COEFFICIENTS FOR STREET SURFACES
Surface Roughness Coefficient
Gutter & Street ..................................... :........
........................ 0.016
DryRubble ..:.:............. e.............................................. :......... 0.035
.
Mowed Kentucky Bluegrass ................................. ....... 0.035
Rough Stony Field w/Weeds..... :........................................... 0.040
Sidewalk & Driveway............................................................ 0.016
MAY 1984 4-5 DESIGN CRITERIA
E
0
APPENDIX 11I
Portions of the Overall Drainage Study for
Oak (Cottonwoods Farm - McClellands Basin
to
OVERALL DRAINAGE STUDY
OAK/COTTONWOOD FARM - McCLELLANDS BASIN
FORT COLLINS, COLORADO
I. GENERAL LOCATION AND DESCRIPTION
A. Location
The Oak/Cottonwood Farm development is located in the southeast part
of Fort Collins, immediately south of Harmony Road and west of Lemay
Avenue. The Oak/Cottonwood Farm development consists of
approximately 271.7 acres occupying the east half of Section 1,
Township 6 North, Range 69 West, of the 6th Principal Meridian. See
the Overall Drainage Plan in the back pocket of this report. This study
will deal only with the area within the McClellands Basin, or all of the
area north of the Mail Creek Irrigation Ditch. The areas south of the Mail
Creek Irrigation Ditch will be addressed under a separate study.
B. Description of Property
The Oak/Cottonwood Farm site contains two existing churches and
assorted retail businesses along Harmony Road, and an existing
psychiatric hospital along Lemay Avenue. The remainder of the existing
site, prior to the start of construction of the single family developments,
consisted of cultivated farmland and natural grasses. The Mail Creek
Irrigation Canal runs across the center of the site from northwest to
southeast. Topography north of the Mail Creek irrigation canal is
generally sloping from northwest to southeast at approximately 1.4% .
Topography south of the Mail Creek irrigation canal is generally sloping
from north to south at approximately 5,7%. Mail Creek and Fossil Creek
is located in the southern part of the development, generally running
from west to east. A small portion of the site, planned for residential
development, is located south of Mail Creek
Three separate single family developments have been designed and
construction started within the Oak/Cottonwood Farm development; The
Upper Meadow at Miramont First and Second Filings, and Castleridge
P.U.D.. Four other developments have been proposed within this Overall
development, and either Final or Preliminary plans submitted to the City
for review; Miramont Third Filing, Oak Hill Apartments, Tennis Center,
and the Courtyards at Miramont. The developments mentioned above
have been shown schematically on the overall Drainage Plan included in
w'1
the back of this report. Reference should be made to each. individual
Drainage reports for more specific detail associated with each project.
II. DRAINAGE BASINS
A. Major _Basin Description
The Oak/Cottonwood Farm site lies within the McClellands Basin, the
Mail Creek Basin, and the Fossil Creek Basin per the vicinity map in the
appendix. The major basin delineations are also shown on the Overall
Drainage Plan.
II1. DRAINAGE DESIGN CRITERIA
A. Regulations
The City of Fort Collins Storm Drainage Design Criteria is being used for
the subject site.
B. Development Criteria Reference and Constraints
The portion of the Oak/Cottonwood Farm site within the McClellands
Basin historically drains southeasterly under Lemay Avenue and through
the adjacent Oakridge development. Downstream improvements have
been completed within the Oakridge development to accept a maximum
storm water runoff of 119 cfs (0.5 cfs per acre) from the
Oak/Cottonwood Farm site per the report titled "Master Drainage Study
for the Oakridge Business Park". Detention requirements for the
McClellands Master Drainage Basin have been established to be 0.20
cfs/acre for the minor, or 10 year storm event, and 0.5 cfs/acre for the
major, or 100 year storm event. Detention ponds ultimately designed for
the area of Oak/Cottonwood Farms within the McClellands Basin should
attempt to be designed to allow for multiple release rates to
accommodate both release requirements. The detention requirement for
the minor storm is not a requirements within the Oak/Cottonwood Farm
site (to be further explained Later in the report).
C. Hydrological Criteria
The SWMM model, as acquired from the Urban Drainage and Flood
Control District, was utilized for the portion of the Oak/Cottonwood Farm
OA
site within the McClellands Basin. The adjacent Oakridge development
utilized SWMM modeling for the 10 year and 100 year storm events with
a different model for each storm event. Due to the number of existing
and proposed detention facilities within this portion of the subject site,
and the need to determine the size of the future detention ponds, a new
SWMM model was developed for the Oak/Cottonwood Farm site. The
2, 5, 10, 25, 50, and 100 year rainfall events, which were obtained from
the City of Fort Collins and required to be run by the City, were run for
a new single SWMM model developed for the site. The new SWMM
model was not.. incorporated into the existing Oakridge site SWMM
model.
D. Hydraulic Criteria.
All calculations with this report have been prepared in accordance with
the City of Fort Collins Storm Drainage Criteria..
E. Variances_ from_ Criteria.
No variances are being sought for the Oak/Cottonwood Farm site.
IV. DRAINAGE FACILITY DESIGN - OVERALL DRAINAGE STUDY FOR.
OAK/COTTONWOOD FARM
mom A. General Conceot
As development continues to occurs within the Oak/Cottonwood Farm
site, the drainage concepts shown on the Overall Drainage Plan in the
back pocket of this report should be followed. Specific detention
requirements exist in the McClellands Basin, where as the Mail Creek
Basin and the Fossil Creek Basins allow for undetained storm water
runoffdirectly to Mail Creek and to Fossil Creek.
B. Specific Details
To. the East of the Oak/Cottonwood Farm property, within the
McClellands Basin, is the Oakridge Business Park and Residential
Community. The appendix includes portions of the text from the Master
Drainage Study for the Oakridge Business Park. Three existing 36" pipes
lie beneath Lemay Avenue, approximately 3000 feet south of Harmony
Road, which in effect direct the Oak/Cottonwood Farm storm water
runoff to the Oak.ridge property. Within the Oakridge development, the
Storm Water Management Model (SWMM) was utilized to model the
anticipated storm water runoff. Within the Oakridge Master Drainage.
Study, SWMM modeled the proposed Oak/Cottonwood Farm
development with a 100 year developed storm water release rate of 0.5
cfs per acre. The Oakridge development 10 year SWMM model did not
include any site specific detention requirements for the Oak/Cottonwood
Farm development. This is due to the existing detention pond within the
Oakridge development and its ability to control and adequately bring the
10 year release rate within the McClellands Basin, at this location, to the
allowable 0.2 cfs per acre discharge. Thus the 10 year detention control
of 0.2 cfs per acre within the McClellands Basin is not necessary for the
Oak/Cottonwood Farm development.
The SWMM model developed for the Oakridge development consisted of
two different models, one model for the 10 year and one model for the
100 year storm events. The .numbering scheme is different in the two
SWMM models. The City Stormwater Utility now requires that SWMM
models route the 2, 5, 10, 25, 50, and 100 year rainfall events. Due to
the differences in the Oakridge SWMM model elements for the different
storm events, and the complexity of the Oak/Cottonwood Farm
development, a new SWMM model has been developed, independent of
the Oakridge SWMM model, for the Oak/Cottonwood Farm development.
The new SWMM model utilizes the same hydrological assumptions and
criteria that the Oakridge SWMM model utilized, but the numbering of the
basins and elements has changed.
The Oak/Cottonwood Farm SWMM model study area was broken up into
sub -basins per the developments proposed in each sub -basins as shown
on the Overall Drainage Plan. Included in the appendix is a SWMM
schematic for the Oak/Cottonwood Farm development. In addition to the
SWMM schematic, the SWMM model numbers have been included on
the Overall Drainage Plan for ease of reference. The SWMM model
includes previously developed areas draining through the
Oak/Cottonwood Farm site as these areas also drain to the three existing
36 pipes under Lemay Avenue. Information was obtained on the
drainage characteristics of the existing developments within the SWMM
area modeled. The SWMM model was calibrated using the basin widths
as a physical parameter, per the City of Fort Collins Stormwater Utility.
For the Pace Membership Warehouse, the Builders Square site and the
Steele's Market site numerous detention ponds exist on these properties. .
The two basins defining these existing developments were not broken
down to show each of the numerous detention ponds on the sites. The
basins were calibrated to release runoff to the Oak/Cottonwood Farm
development at the projected* design rates of these sites. For the
Collinswood Treatment Complex immediately north of the existing 36"
4
pipes, the SWMM model was also calibrated to release runoff from this
property at a target design rate for the site.
Once the SWMM model was calibrated for the existing developments
within the study area, the study area was evaluated in reference to the
required 0.5 cfs per acre ,100 year storm event, release rate. Future
detention pond sites were planned with the Client to the best extent
possible in order to determine how the study area would drain. Each
detention pond system was modeled with a release rate of 0.5 cfs per
acre during a 100 year storm event.
The off -site residential neighborhood to the west of the Oak/Cottonwood
Farm site drains southeasterly and through the first planned development
in the Oak/Cottonwood Farm. site. The extent of this off -site area was
estimated to be 14.75 acres per the Mail Creek. Hydrologic Information
drawing by Water Engineering & Technology, Inc. dated 2-29-90. For
this report, it has been assumed that the separation between the Mail
Creek Basin and the McClellands Basin has been shown correctly on the
Mail Creek Hydrologic Information drawing. Per a conversation with the
City Stormwater Utility, it was learned that within the Mail Creek Basin
it was assumed during storm events that the Mail Creek Ditch is flowing
full and land above the Ditch will sheet flow storm water directly over
the Ditch and downstream to Mail Creek. Per a meeting with John Moen
(Ditch Rider of the Mail Creek Ditch) the Mail Creek irrigation ditch has
no available capacity for storm water runoff and during a storm event
storm water runoff sheet flows directly over the Mail Creek irrigation
ditch. This off -site storm water runoff from the 14.75 acres of existing
residential neighborhood only has a minor impact to the Oak/Cottonwood
Farm site and these off -site flows are collected in the First Filing
development as .discussed later in this report.
Included on the Overall Drainage Plan is a summary table of the proposed
detention ponds. their required capacities, and their maximum allowable
release rates (Summarized below). The detention pond capacities were
sized with the anticipated type of development contributory to the ponds
at the time of this report. As the development of these sites progresses
to final design, the SWMM model should be updated to finalize the size
of each detention pond per its final. type of development. Outflow from
each pond shall utilize a rating curve based on the ultimate pond
configuration. The rating curves for detention ponds 321 (Associated
with Miramont First Filing), and _Detention pond 340 (Associated partly
with Miramont Second Filing) have been included in. the model with this
update.
Minimum
Maximum
Detention Pond
Storage
Outflow
303
0.6 ac.ft
3.0 cfs
306
1.0 ac.ft
4.0 cfs
313 (5c� Re.►�s�l)
4.2 ac.ft
22.0 cfs
321 �'�a D
3.5 ac.ft
7.0 cfs
322 ���,)54
2.1 ac.ft
11.0 cfs
340 hr%t O
4.9 ac.ft
66.0 cfs
Detention ponds 322 and 306 have not been modeled with a* rating
curve, but with a pipe outlet preliminarily sized to approximate a release
rate of 0.5 cfs per acre. As final design occurs around these ponds, a
rating curve should be built into the model to better approximate actual
conditions. The reader should be advised that with the insertion of a
rating curve into the 'model, the required minimum pond size can be
expected to be increased.
With this update, the SWMM model parameters for Basin 201 were
modified to reflect a higher impervious factor. This caused the require
storage volume of Existing pond 321, located between Miramont 1 st and
2nd Filing to increase. A drainage certification has been performed on
Miramont 1 st Filing, and the actual volume of the pond constructed was
found to be approximately 3.8 ac.ft., or large enough to account for this
change in model parameters.
The model also shows a detention requirement for conveyance elements
301, 303, 307, and 311. The. following methodologies were applied
during the modeling of these conveyance elements:
Element 301 - Steele's sites (Basin 204)
Per the Harmony Market 3rd Filing drainage report, the designed
release rate at this location is 24 cfs. No SWMM model rating
curves are available for the detention ponds existing within this
basin. For the SWMM modeling herein, a conveyance element was
derived which modeled the maximum release rate of 24 cfs
occurring from this basin, and caused water over and above this
release rate to be detained at the upstream end of the conveyance
element. This way of modeling the existing facilities enables the
model to realize the intended release rate at this location so the
downstream systemanalysis can be completed utilizing the full
upstream impact. Per 'the SWMM Model output, the water
detained at conveyance element 301 is 1.3 ac.ft.. The actual
6
detention volume. available within basin 204 based on field
verification is 3.4 ac.-ft.. Because the existing available volume
is greater than the required volume per the SWMM Model, this
method of modeling Basin 204 is adequate.
Element 307 - Pace and Builders Square (Basin 203)
Per the Harmony Market 2nd Filing drainage report, the designed
release rate at this location is 6 cfs. No SWMM model rating
curves are available for the detention ponds existing within this
basin. For the SWMM modeling herein, a conveyance element was
derived which modeled the maximum release rate of 6 cfs
occurring from this basin, and caused water over and above this
release rate to be detained at the upstream end of the conveyance
element. This way of modeling the existing facilities enables the
model to realize the intended release rate at this location so the
downstream system analysis can be completed utilizing the full
upstream impact. Per the SWMM Model output, the water
detained at conveyance element 307 is 5.3 ac.ft.. The actual
detention - volume available within basin 203 based on field
verification is 8.0 ac.-ft.. Because the existing available volume
is greater than the required volume per the SWMM Model, this
method of modeling Basin 203 is adequate.
Element 303 - Church Site (Basin 205)
No SWMM model rating curves are available for the detention pond
existing within this basin. For the SWMM modeling herein, a
conveyance element was derived which modeled the maximum
release rate of 0.5 cfs/acre occurring from this basin per the
criteria within the McClellands Basin, and caused water over and
above this release rate to be detained at the upstream end of the
conveyance element. This way of modeling the existing facilities
enables the model to realize the intended release rate at this
location so the downstream system analysis can be completed
utilizing .the full upstream impact. The actual detention volume
available within basin 205 by a field verification is outside the
scope of this project.
Element 311 - Collinswood Treatment Complex (Basin 207)
No SWMM model rating curves are available for the detention pond
existing within this basin. For the SWMM modeling herein, a
conveyance element was derived which modeled the maximum
7
release rate of 0.5 cfs/acre occurring from this basin per the
criteria within the McClellands Basin, and caused water over and
above this release rate to be detained at the upstream end of the
conveyance element. This way of modeling the existing facilities
enables the model to realize the intended release rate at this
location so the downstream system analysis can be completed
utilizing the full upstream. impact. The actual detention volume
available within basin 207 by a field verification is outside the
scope of this project.
A network of storm sewers and channels exist along the west side of
Lemay Avenue, and along the westerly property line of the Hospital and
Church, and these systems transports stormwater runoff from the Pace
Membership Warehouse, Builders Square, Steele's Market, Church, and
Collinswood Treatment Complex to the existing 36" pipes under Lemay
Avenue. As the Tennis center project is final designed, those existing
conveyance elements, particularly those associated with the easterly
property line of the Tennis center should be examined to determine the
effects of development. This system will need to be extended across a
portion of the Oak/Cottonwood Farm site to the existing 36" pipes. For
master planning purposes, the outlet to detention pond number 313 is
proposed to be connected into the existing storm sewer system on the
west side of Lemay Avenue and routed directly into the existing 36"
culvert under Lemay Avenue.
The original Overall Drainage Plan showed Detention pond being located
over towards the southwesterly corner of the existing Hospital site.
During construction of The Upper Meadow at Miramont first Filing, it was
determined that pond 313 would be located adjacent to Boardwalk Drive.
This shift caused the contributory area to Pond 313 to decrease, and the
contributory area for Pond 340 to increase. The future Park site will now
have detention provided within Detention pond 340. The shift in the
location of the pond was discussed with the Parks and Recreation
Department. Detention pond 313 will also have a permanent water
surface to store irrigation water forthe adjacent residential developments.
The SWMM model and the overall drainage plan reflect the shift in pond
313.
With the development of the first residential community within the
Oak/Cottonwood Farm Development, titled The Upper Meadow at
Miramont First Filing, the construction of Boardwalk Drive from Oakridge
Drive to Lemay Avenue was required. With the development of
Boardwalk Drive, and the need•for the developable land lying west and
southwest of Boardwalk Drive to drain under Boardwalk Drive and to the
1:1
existing 36" culverts under Lemay Avenue, a second drainage system
was master planned along Boardwalk. A series of storm sewers and
open channels was constructed along Boardwalk from the existing 36"
storm sewers under Lemay Avenue, upstream to Oakridge Drive. A
detention pond was planned and partially constructed for the property in
the northwest corner of the Oak/Cottonwood Farm site with an 18"
storm sewer outlet to release runoff at the required 0.5 cfs per acre. On
the Overall Drainage Plan a storm sewer system has been shown in
Boardwalk Drive to transport the northwestern detention pond outlet
flows to the downstream storm sewer and open channel system. This
system was built according to this overall plan. At the time of this
update, Detention pond 322 will outlet onto Boardwalk Drive and be
conveyed by curb and gutter to the storm sewer system (a combination
of pipes and open channels). An agreement between GT Land and Front
fRange Baptist Church exists that limits the release from basin 202 to
5.57 cfs for the 10 year storm event and 11.45 cfs for the 100 year
storm event (Based on the capacity of Boardwalk Drive Curb and Gutter).
Detention pond 321 will outlet on the west side of Boardwalk and be
conveyed downstream to Lemay Avenue by the same series of pipes and
open channels. A copy of this agreement has been included in the
appendix of this report.
The storm sewer system in Boardwalk Drive was sized to carry the 25
year storm runoff event due to the location of the proposed high and low
points in Boardwalk Drive. As storm events occur greater than the 25
year storm event, minor ponding is planned to occur at the low points.
In the event the storm sewer systems become plugged, overflow swales
have been provided to redirect storm water runoff to the proposed open
channel system to safely convey storm water runoff to the proposed
detention pond number 340 and the existing 36" culverts under Lemay
Avenue.
In order to achieve the required 0..5 cfs per acre release at the existing
36" culverts under Lemay Avenue, detention pond number 340 is
planned immediately upstream of the 36" culverts. During final design
of this detention pond, the hydraulics of the connection from the
detention pond to the existing 36" culverts will need to be worked out
to ensure the 0.5 cfs per acre release rate is not exceeded. A preliminary
rating curve based on the proposed ultimate design of this pond has been
included in the model, and the calculations are included in the appendix
of this report. The rating curve included is based on the existing 36"
pipes under Lemay being built according to plan, and that rating curve is
a preliminary design only. As pond 340 is finalized, these existing 36"
culverts will need to be reevaluated and the new rating curves based on
® 9
actual field conditions. The pond 340 size will need to be reexamined &
downstream flows to Oakridge will need to be decreased to 119 cfs (the
model currently shows a release to Oakridge of 129 cfs). Pond 340 will
need to be permanently designed when the area of the Overall plan
known as the Hamlet is developed, (the Hamlet was defined as a part of
the Miramont Phase 3 Preliminary Plan), or basin 213 is developed.
V. EROSION. CONTROL
A. General Concept
The Oak/Cottonwood Farm site lies within the Moderate and High Rainfall
Erodibility Zone and. within the Low to Moderate Wind Erodib.ility Zone
per the City of Fort Collins zone maps. Per the City of Fort Collins
Erosion Control Reference Manual for Construction Sites, at the time of
final design of the site, the erosion control performance standard will
need to be calculated and appropriate measures taken to control erosion
from the site.
VI. CONCLUSIONS
A. Compliance with. Standards 41
All computations within this report have been completed in compliance
with the City of Fort Collins Storm Drainage Design Criteria..
B. Drainage Concept
The proposed drainage concepts adequately provide for the transmission
of developed on -site runoff to the proposed detention facilities. The
sizes and locations of each detention pond within the study area will
enable the Oak/Cottonwood Farm site to develop in conformance with
the McClellands; Mail Creek and Fossil Creek Basin requirements. The
street systems will need to convey storm water runoff to the
downstream outlets without exceeding the capacities of the street
conveyance systems. If the street capacities are exceed, storm sewer
systems may be required to transport storm water runoff to the
downstream outlets. Per the City criteria, only the initial storm event is
required to be transported to the downstream outlets by storm sewer
systems once the street systems become overloaded. City requirements
for the transportation of the 100 year developed flows must also be
observed and complied with. Each of the on -site detention ponds in the
McClellands Basin will be required to provide one foot of freeboard and
10.
l
an emergency overflow outlet in,the event the outlet structure and pipe
become plugged. All on -site drainage facilities will be maintained by a
homeowners association, or other entity created by the developer. The
City of Fort Collins will maintain the storm sewer systems located within
dedicated right-of-ways.
REFERENCES
1.
Storm Drainage Design Criteria and Construction Standards by the City of Fort
Collins, Colorado, May 1984.
2.
Erosion Control Reference Manual for Construction Sites by the City of Fort
Collins, Colorado, January 1991.
3.
Master Drainage Study for the Oakridge Business Park in Fort Collins, Colorado,
by RBD Inc., September 1990.
4.
Final Drainage and Erosion Control Study for The Upper Meadow at Miramont
First Filing, Fort Collins, Colorado, by RBD, Inc., November 10, 1992.
5.
Final Drainage and Erosion Control Study for The Upper Meadow at Miramont
Second Filing, -Fort Collins, Colorado, by RBD, Inc.
6.
Final Drainage and Erosion Control Study for Castleridge at Miramont First
Filing, Fort Collins, Colorado, by RBD, Inc., October 7, 1993.
7.
Preliminary Design Report for Mail Creek Stability Study, by L-idstone and
Anderson & TST, Inc., January 28, 1994.
8.
Preliminary Drainage and Erosion Control Study for Miramont 3rd Phase P.U.D.,
Fort Collins, Colorado, by RBD, Inc., February 4, 1994.
9.
Final Drainage and Erosion Control Study for Miramont P.U.D. Third Filing, Fort
Collins, Colorado, by RBD, Inc., April 4, 1994.
10.
Preliminary Drainage and Erosion Control Plan for the Oak Hill Apartments, Fort
Collins, Colorado, by RBD, Inc., February 4, 1994
11
CLIENT KA I AMnkrr L{--4
3INC PROJECT�,t -lS,'» CALCULATIONS FOR _�1�/11`A It /Ic�f�Ct
Engineering Consultants MADE BY�DATE '+•�CHECKEDBY DATE SHEET12f2_OF
r.
:
:
Gp1!lV�Y4�J
Zos
oND t
t. .
i ..
320 t 323 + 4._
3ZI t r �9 t
i Z14 _
....
r %011
771
.:
CLIENT Ne 1f,041G
bV-E/9L-
JOB NO. •' OX -ao /
PROJECT 27262w00o -
CALCULATIONSFOR
Engineering Consultants
MADE BY KwG
DATE'/ L HECKEDBY
DATE
SHEET OF
L
DETE72M/wE BAS/.V 'PA,PA•METeR3
__
t
64. GA7CNME�JT.
; 7D 77e/B•
-
IU(iM BER
W/OT/!•
i9GkE5
../r1P
ScoPE._..
_.�
-
1
j_
700
50
��.:.
a
+
903
.ZS
O'
7, oo.
.
/ ODi
SO
_.......
S9o':
65-0.1
7.70
:: 70
O, 900i
1
I ....
{ . 2d,7
1.
I c
/3.8
S 7
2.35
!
zn8
4so'
327v
-7o
h 70 9, ; _44
Zo1�
y3S
23.y....._.. yo.....
<•8S ay
...
f
l
Z2
Y00.�
y.2
F�
3.80 9e
j
S
_
2�3
goo'
.70
... ..:
21ti
RO
r. ►��
ACV -
.....
.. 215I
o,70
90
Z70/..
WE
}
b67Epm//VE P,�onJ VEYA.yCE 7°�REi /YlE rfiQS_
,
Coa�E1A/JGE
_ .._ . ELEMENT
TYPE. IVIPWM I-EN6TN
i D b9ir-MR
510PE LEFT
s/oESlof
R/6NT `I/''
SiGE SCLIl
DE/TNOF�'vt[ ck�+ �c
oR f/I'ED/A.... _..:
PIPE
Z.Z7
96
0
0
.613
Z.Z7
i
302
G//pN,t�L
q.O
Z&O
10021
2
2
.035
4. Coo
303
_. 3 oy
plrc.
Z.Z7
90
•0070
O' .
o
.0/3 ..
3os
CHA/vi✓£L
y.o
YGO
,0021
Z
Z
•035
4-
�ZS
ut� 3oG
PI PE.
1,25
/D
,0038
O
0
�013
/
j
__ .. 307
PfPE
/,5O
120
•003$
30S �
CNANNFL
D
1200
OOSo
y
y
, o3s
:. %: /O •
'
PIPE
2.25
is
0
_...
!
3/o
p1pE
2.50
853
•0123
0
0
pol is 3//
PIPE
bCo
315-
.0020
O
.DD
900
:OIoo
d
Po LjD9[3
P1pE
2,ZS
1.31D
, 00.38
O
0
WC
Engineering Consultants
CLIENT _ AV0P/1/CAB .1i lrW Z- -_- JOBNO. Soy 0O /
PROJECT CD7-7W uWOO-0 CALCULATIONS FOR SU1MM /'71e10E [.
MADEBY KwG DATEy y. Z CHECKEDBY DATE -SHEET _L.L_OF
1:���:.������e.�/NE- ca✓��-ya.✓�F� P.�,eAr���rE�s ,
COn i'EY A+UGF TYOE WIVTW cR : GEN6rl/ SLOPE LEFT .f x 16 //r
Q07AgEL
s;oo:.
3z1.
PIPE
:. 32Z
P! PE
/,SO
0
D.
32.3
P/FE
.:_
- PIPS
3.00
lZo.:..
.cYlSo.
...: 6 . ..
o.._..
3ZS
GHI AIVE
y,00
y20
.0050
4
4
3Z6
-PIPE
3,5'0
/00
,OOSO
o
O
4-
32$
PIPE'
A7S
3 Z9
CHAVIM
5.00
330
PIPE
/.SO
33!
PIPE.:
3.00
3yo
PIPE.'
d. Lo
/00
2110
80
Bo
Io
.oloo
.QOSo
, 0050
,00so
.00 /H6
y
y
0
0
0
0
O
._,_.
riN it
: IJE�TH A� Fi%LL Cy/?itN'2
D!3
,
42 Q �ueu3
,' Ol3
SO / .._
D13
3.50 ` (ZSY12 GeS J)
. 03S
3.0 0
,
. 0 / 3
A 7.S (25 YR DES/6 v)
-1A DES/6.v)
.o13
3•00 . Czs.Y,eoes�byj
D /3
a
b.lo C't�'rl>,1cv CUYaiE
,
CLIENT V%Q D lCK IME<JL JOB NO. 505/-06 /
PROJECT CO TTON ",VoA CALCULATIONS FOR S W m m MOD ILL
Engineering Consultants MADEBY/? DATEYZM&-CHECKEOBY DATE SHEET 20. OF
INC
Engineering Consultants
i
_ N t — )rr-.al
... 1• a i t i . + . { � .. , i .. ., ...: � :. .. C.��; P/1 Li L e . � - i {�.yl MUL.4-7
t � �
{ j ' - i
j fri `
I
CLIENT(= �+� li' JOBNO.22`--�
PROJECT 1 fl M��^—,*,r Zf -Alm_ CALCULATIONS FOR—=-���
MADEBY-. DATECHECKED BY DATE SHEET OF
p
r�
V
{49�SAG, 0124�
Ir
:1 i
Ir
IF
d
�!_ D • STr>eIN E
CLIENT " 1 2-MV 1, l r:l t!SG ^� JOB; •No. �
NC PROJECT om�- 1L L P ^ TC CALCULATIONS FOR-�L.��T Ph � r_t Al
Eng nftring Consultants MADE BY_e21.DATE4-S14CHECKED BY- DATE SHEEP OF
.1 ..:.l..T .� ' - � ,. .t..+. J• a -I••-+ t !- ! i ' i.-i .. .�a:.i- ' .. L _a_ ` 4 .+. a;.t t_. i L.s. i
t �t + 1_} 1 f •{' i.,t.- t • r a + t - !- ' ' r. 2 ' 1 Y..�._-, �.y� -t1 •+ -« .� -'+• -
i_y_�_1 ._r►.}.� P-�; _`..� � T7t�]GT -• : PV� � � aT'1,�iN�� !tia.�31
+ � 1-. '�-•}y !'_.r.�_,r T� t� .._�. .. « ..�, f •.i.1 � .t f.! � r f--t-t 4 .. .a '
!- I _ ��+ 1 . 1J V � W 1 ,..' Pt.7 *i iJ � ,, -T�IG7 . •Q i. « r , i 1 �- •r •-.. -+
{ t I �I .�.. rL.F_- .;-i. -+I• .l..a �. _ 1..f .i •-+ .i. .j + a..i ` _ .._
- •r
ram. T..,
1 1 ..-i � 1- _� �"' •. 'i-' �.'' �' � -i ..mot. i ;.i:y 1' r. ....
I '+- ' I'- ,� t I 1 t ' •- • • « i. -+' i ,.'1 i '+' � ' i ' J' � . i:. ' J ? . J '
—
7i. a 1 . i.. i 1 a 1 t
L 4}� .-/`.i
{ , _i=-�-:• i• a 11.E !A
• T
• � J� Ltil
r }JT�OL
.�.�'FT .. .
��1}..`�J�l � ' �.Po-�;o-"cio '• f �(•-. z : Ins - �•r; t ��� '+ 4.9 Cog.,
I+ s i } .. _ ( 1. , .!_ -f a. •� ,. ..
-rt , .I._ , : , , SJ �..f.r•G�i V�. y �_ i47�7 �!i J 1 -� i t
I.I..s,-r I y t. a , r� + t �;•-+ �+ 1-•+
j-.� t- +-• 1 �' + fi } 1 ! i 1 .1 1 i t' 1• t 1 "! t I ; •.1
- j -_ ! '.r • I i t i t t_ I i y.... 1. i L4..
j 1
i i-' r �•Y•7 ! i } r .'+`-._J c .! 1 �.s !.- ice. t Li-.- _1,a...
�...-•1-• •+ 1 t• ;• f_ i .I..7..,..r } t } ; .i. t 1 •. � i
. - ---� •--�•'�•11-i-+ �•-�-I-1 r -j j + }-i1 j, .j,.T.i.l..j. t I .t l f-T-•k-i•+-r �.a •-+-. }._. •—.r-�__............
_� .1 •'�-i:,{ i 7 •j- 1, '- i ?_� t y..� _L T } i . t , t r • .. 1 «. i .4-•:
,' ..1 1_ .(. � -1_j_L 1 L -�. a ! + s � y. i . • .! t I 1
-r t , i i , i•�
•1 1. t l l ! i t 1 1 •, 1
APPENDIX IV
Stuffier Envelope
Drainage and Erosion Control Plan
Preliminary Drainage and Erosion Control Plan (Overall area; for reference)
Final Grading Plan for Courtyards atMiramont Second Filing
Erosion Control Security Deposit Requirements
I& April 24, 1995
Project No; 1410-01-94
Re: EROSION CONTROL SECURITY DEPOSIT REQUIREMENTS:
The Cottages at Miramont P.U.D.; Fort Collins, Colorado
A. 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.
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..
a The cost to install the proposed erosion control devices for the Courtyards at
Miramont P.U.D., Second Filing is $2,525.00. 1.5 times this estimate is $
3,787.50.
i. unit prices have been provided by Connell Resources.
b. Based on current data provided by the City of Fort Collins Storm Water Utility,
and based on an actual anticipated net affected disturbed area during
construction of the The Cottages at Miramont P.U.D.. (approximately 2.22
acres) we estimate that the cost to re -vegetate the disturbed area will be
$1,430.00 ($650.00 per acre x 2.20 acres). 1.5 times the cost to re -vegetate the
disturbed area is $2,145.00.
i. The 2.22 acres is the actual area of the The Cottages at Miramont P.U.D.,
housing project.
ii. The $650.00 per acre for re -seeding sites of less than 10 acres was quoted
to us by the City of Fort Collins Storm Water Utility staff.
CONCLUSION:
The erosion control security deposit amount required for this project will be $ 3,787.50.
Because of the anticipated construction phasing, separate erosion control deposit amounts
may be established for the phase to be constructed.
4836 S. College, Suite 12 Fort Collins; CO 80525 (303)22&5334