HomeMy WebLinkAboutDrainage Reports - 01/19/1990FINAL DRAINAGE INVESTIGATION
FOR
LAURIE SUBDIVISION
FORT COLLINS, COLORADO
Prepared for
Dr. William Musslewhite
5001 S. Sheilds Street
Fort Collins, Colorado 80526
December 29, 1989
Commission No. 1180-01-01-02
CONSULTING ENGINEERS
FOUNDATION ENGINEERING
320 N. CLEVELAND AVENUE
LOVELAND, COLORADO 80537
f..
December 29, 1989
Commission No. 1180-01-01-02
Dr. William Musslewhite
5001 S. Shields Street
Fort Collins, Colorado 80526
Dear Dr. Musslewhite,
The enclosed report represents the results of the final drainage investigation
for the LAURIE SUBDIVISION located in the Northeast Quarter of Section 3,
Township 6 North, Range 69 West of the 6th P.M. Larimer County, Colorado.
This investigation was based upon the proposed site development plan and plat;
proposed site development construction plans; on -site observations; and
available topographic information. The investigation was performed in
accordance with the criteria established in the City of Fort Collins -"Storm
Drainage Design Criteria and Construction Specification Standards" manual.
It is our opinion that the proposed construction is feasible provided that the
recommendations contained in the attached report and the incorporated final
design are performed in accordance with the final approved plans for the
project.
FOUNDATION ENGINEERING
KWP/drm
s, please call.
TABLE OF CONTENTS
Letter of Transmittal i
Table of Contents
Scope 1
Site Description 1
Existing Conditions 1
Proposed Development 2
Conclusions and Recommendations 2
EXHIBITS ,�/�
Vicinity Map — V v 0411 Exhibit A
Calculations Exhibit B
I�
The following report represents the results of a drainage investigation for a
proposed development to be known as the LAURIE SUBDIVISION located on a
parcel of land situated in the Northeast Quarter of Section 3, Township 6 North,
Range 69 West of the 6th P.M., Larimer County, Colorado. The investigation was
performed for Dr. William Musslewhite. The purpose of this inv igation is to
determine the effects of the proposed development on the ar s xisting
drainage conditions and to determine the improvements, if any, and the
appropriate sizing for proposed improvements so that it may be incorporated
with the construction of the project. The conclusions and recommendations
presented in this report are based upon the proposed site development plan and
plat; proposed site development construction plans; on -site observations; and
the available topographic information. The analysis was performed in
accordance with the City of Fort Collins- "Storm Drainage Design Criteria and
Construction Standards" manual.
SITE DESCRIPITION
The site is generally rectangular in shape and contains approximately eight
acres. The sites East-West dimension is approximately 1,150 feet and its
North -South dimension varies from approximately 390 feet at the westerly
boundary to approximately 280 feet at the easterly boundary. The site abuts the
westerly right-of-way of Sheilds Street at a point approximately one-half mile
south of Harmony Road. The site is located on the Burns Tributary of the FOSSIL
CREEK DRAINAGE BASIN.
The site is presently used as a large residential tract with the existing
structures located at the southeast corner of the site near Sheilds Street. The
Pleasant Valley and Lake Canal passes throughh the adjacent property to the
north with a lateral of that ditch flowing through tli€site. Near the center of
thsite is a ravine that has been created by scouring action associated with an
W overflow discharge from the Canal as it flows across the site toward the South.
According to the irrigation company's officials the overflow to the ravine is
designed to discharge a maximum flow of 30 c.f.s. (cubic feet per second)
East of the lateral ditch passing through the site, the property slopes gently to
the East toward Sheild Street at a slope of approximately 2%. The area below
the ditch is irrigated and is used for pasture except for the residence and
out -buildings at the southeast corner of the site.
1
The portion of the site that lies West of the ravine is not irrigated and slopes.
rather steeply at approximately 15% toward the Burns Tributary of FOSSIL
CREEK. The area is sparsely veaated with ground cover consisting mainly of %
native grasses and sage brush. The site abuts THE RIDGE Subdivision at the West
and South. AO1A4
The site receives run-off from the properties to the North and West. For the
purposes of this investigation, the area above the Pleasant Valley and Lake
Canal was not considered to effect the conditions onsite since the ditch flow is
controlled to the extent that there is an existing. overflow structure that
directs excess flow to the ravine through the site, as previously stated. The
area to the North consists of approximately 10.5 acres which drains easterly to
Sheilds Street and then southerly along the west side of Sheilds Street through
the site. n area of a roximatel 2.5 acres drains into the smaller sid ravine
that enters the site at the mid -point of lbe.tbe nQrthern boundary.,/00
pproximately 4.5 acres drains directly into the major ravine before it enters
the site near the northwest corner. A `I
PROPOSED DEVELOPMENT
ow
A , ,0
r
The proposed construction is to consist of a v S'� ry clinic with associated
parking that is to be located near the northeast corner of the site adjacent to
Sheilds Street. A new cul de sac street is to be constructed to serve the new
clinic and the existing residence. The cul de sac is to be extended to a circular
turn -around west of the existing and proposed construction in order to provide
access to the area to the west. At this time the future development to the west
is being proposed to be residential in nature with nine (9) lots to be platted.
CONCLUSIONS AND RECOMMENDATIONS 2 /V
1. The proposed development will retain the existing drainage patterns./Q'
2. The site is located in the FOSSIL CREEK DRAINAGE BASIN. The site is not �li1 GG�wc
located within the floodway or flood plain. p„
3. All development is to be performed in accordance with City of Fort Collins
Standards and Specifications.
1�
4 nsite detention of stormwater is not recommended due to the sites " Al
proximity to the existing "Major" drainage course. 1`%f? itWwAezwn�
2
VICINITY � � AP
7
CALCULATIONS
EXH�I�BIT "B"
e
Dr. Musslewhite-Laurie Subdivision Commission No. 1180-01-01-02
By: DRM Date: Dec. 29, 1989
Calculations for Drainage Investigation for LAURIE SUBDIVISION located in the
NE1/4 of Section 3, Township 6 North, Range 69 West of the 6th P.M., City of
Fort Collins, Larimer County, Colorado
Total Site Area = 8 acres +/-
EXISTING CONDITIONS
Rational "C" Factor = 0.20 for Offsite Irrigated Areas
"11 of= 0.25 for Offsite Steeper Non -irrigated Areas
to
" of
= 0.25 for Onsite Irrigated Areas
to
" " = 0.30 for Onsite Steeper Non -irrigated Areas
PROPOSED DEVELOPMENT
Rational "C" Factor �or Lawns and Landscaped Areas
itof= 0.95 for Roofs, Decks, Patios, etc.
"of= 0.95 for Streets, Drives, and Parking
Lawns and Landscaped Areas = 29,413 sq.ft.
Roofs, Decks, Patios, etc. = 4,400 sq.ft.
Streets, Frives, and Parking = 13,800 sq.ft.
Area of Site Consideration = 325' x 146.5' = 47,613 sq.ft.
"�avg = {(29,413 x 0.225) + (4,400 x 0.95) + (13,800 x 0.95)) / 4�,613
cllavg = 0.50
C - . 50
Refer to following calculations for runoff quantity determination.
CULVERT SIZING w .
New culvert to be installed at cdf"de sac street from Shields Street. The culvert
is considered to be at "Inlet Control". Based upon the runoff calculations the U"
design flows at this point are: Q2 = 6 cfs and Qloo = 20 cfs ; therefore -
Using the Design Nomograph for Circular Pipe at Inlet Control:
@ HW/D = 1.0 and Q = 6 cfs an 18" dia. pipe will be sufficient
@ HW/D = 1.5 and Q = 20 cfs a 24" dia. pipe will be required�-
USE a 24" dia. pipe to meet both conditions 41'x �,�,�
Dr. Musslewhite-Laurie Subdivision Commission No. 1180-01-01-02
By: DRM Date: Dec. 29, 1989
CULVERT SIZING(cont.)
2.) Culvert at cul de sac street crossing on ravine in central portion of site. 7
Design "Q"= 49.5 cfs (from report) o
Since irrigation flow is incorporated consider only HW/D = 1.0
From Design Nomograph: @ HW/D = 1.0 and "Q" = 49.5 cfs a 42" dia. pipe will
be sufficient. Since a 48" culvert exists immediately downstream and
considering for trash build-up at he culvert entrance, recommend a 48" dia.
pipe.
The primary area of concern is the ravine running thru the site. This may require. VM ,f
some type of "drop structures" along its course and inlet and outlet protection J
at the proposed culvert under the cul de sac street. Additional protection at the
inlet and outlet ends of the culvert at Shields Street should also be provided. 7 ►� W
ray
(The City's Standard Erosion treatments for wind and storm -runoff should also � .
be incorporated during the course of construction. 44,0 4"'
�t7
3
Calculated By: DRM STORM DRAINAGE INVESTIGATION # 1180-01-01-02 Client : Dr. Musslewhite
Date : Dec. 29, 1989 RATIONAL METHOD PROCEDURE Project: LAURIE SUBDIVISION
Checked By: KWP Design Storm: 2 YEAR Existing Conditions
Location Point Area Runoff Coeff. Freq. Factor AxCxCf Flow Time Flow Time Rain Intens. Runoff Comments
Description Designation (acres) C. 'cf. Tchan(min.)Tc (mi 'I"(in./hr,)'Q'(c.f.s.)
Offsite Area 'A' Pt. A 10.5 0.2 1 2.10 7 1 5 2.4.41
Onsite Area 1 Pt. A+1 2 0.25 1 0.50 20 1.85 0.93
Pt. A+1 12.5 0.2 1 2.50 ? 20 1.85 4.63 Flow at west side of Shields flowing to south
�xn Offsite Area 'B' 2.5 0.25 1 0.63 V 10 2.5 1.56
� VI'Ai Onsite Area 3 B+3 1 0.3 1 0.30 10 2.5 0.75
J Pt. 3.5 0.26 1 0.91 10 2.5 2.28 Flow at 'minor' ravine at north central area
p1 Offsite Area 'C' Pt. C 4.5 0.25 1 1.13 W' �I 0 2.5 2.81
Onsite Area 4 Pt. C+4 1 0.3 1 0.30 1 0 2.5 0.75
Pt. C 6.5 0.26 1 1.43 iii��� 10 2.5 3.58 Flow from north and west- add 30 c.f.s. irrig
111 33.60 Total with irrigation flow
n Onsits Area 6 Pt. 6 1 0.3 1 0.30 10 2.5 0.75
Total at Ravine Pt. + 10 0.26 1 2.60 115 2.1 5.46 Flow exiting site - add 30 c.f.s. irrig.
35.50 Total with irrigation flow
Onsite Area 2 Pt. 2 1 0.3 1 0.30 10 2.5 0.75 Flow to south offsite overland
Onsite Area 5 Pt. 5 1 0.3 1 0.30 1 10 2.5 0.75 Flow to south offsite to "major' ravine
Calculated By:
DRM
STORM DRAINAGE INVESTIGATION
# 1180-01-01.02
Client : Dr. Musslewhite
Date : Dec. 29, 1989
RATIONAL METHOD PROCEDURE
Project: LAURIE SUBDIVISION
Checked By :
KWP
Design Storm:100 YEAR - Existing Conditions
Location
Point
Area
Runoff Coeff. Freq. Factor AxCxCf Flow Time
Flow Time Rain Intens.
Runoff Comments
Description
Designation
(acres)
C.
'cf.
Tchan(min.)
Tc (, ' .) 'I'(in./hr.)'Q'(c.f.s.)
Offsite Area 'A'
Pt. A
10.5
0.2
1.25
2.63
1
6
15.75
Onsite Area 1
Pt. A+1
2
0.25
1.25
0.63
20
5.15
3.22
Pt. A+1
12.5
0.2
1.25
3.13 I
20
5.15
16.09 Flow at west side of Shields flowing to south
Offsite Area 'B'
Pt. B
2.5
0.25
1.25
0.78
1 0
7
5.47
Onsite Area 3
Pt. B+3
1
0.3
1.25
0.38
1 0
7
2.63
Pt. 8+3
3.5
0.26
1.25
1.14
1 0
7
7.96 Flow at "minor' ravine at north central area
Offsite Area 'C'
Pt. C
4.5
0.25
1.25
1.41
1 0
7
9.84
Onsite Area 4
Pt. C+4
1
0.3
1.25
0.38
1 0
7
2.63
Pt. C+4
5.5
0.26
1.25
1.79
1 0
7
12.51 Flow from north and west- add 30 c.f.s. irrig
42.50 Total with irrigation flow
Onsite Area 6
Pt. 6
1
0.3
1.25
0.38
10
7
2.63
Total at Ravine
Pt. B+C+6
10
0.26
1.25
3.25
1 5
6
19.50 Flow exiting site = add 30 c.f.s. Irrig.
49.50 Total with Irrigation flow
Onsite Area 2
Pt. 2
1
0.3
1.25
0.38
1 0
7
2.63 Flow to south offsite overland
Onsite Area 5
Pt. 5
1
0.3
1.25
0.38
1 0
7
2.63 Flow to south offsite to "major" ravine
I
Page 1
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,(� ram, Cps- f v... bat, NJ: H
too
rat . S ` -{-- (. &70. L'Z (- C
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S 3
Calculated By :
DRM
STORM DRAINAGE INVESTIGATION
9 1180-01-01-02
Client: Dr. Musslewhite
Date: Dec. 29, 1989
RATIONAL METHOD PROCEDURE
Project: SHIELDS STREET PR RTY
Checked By:
KWP
Design Storm: 2 YE Developed onditions
Location
Point
Area
Runoff Coeff. Freq. Factor AxCxCf Flow Time
Flow Time
Rain Intens.
Runoff Comore
Description
Designation
(acres)
C.
'cf.
Tcha
Tc (min.)
'I'(in./hr.)'O'(c.f.s.)
Offsite Area 'A'
Pt. A
10.5
0.2
1
2.10
1 5
2.1
4.41
Onsite Area 1
Pt. A+1
2
0.5
1
1.00 5
1.85
1.85
Pt. A+1
12.5
0.25
1
3.13 20
1.85
5.78 Flow at west side of Shields flowing to south
lJ
O=6 cis for Culvert sizing
Offsite Area 'B'
Pt. B
2.5
0.25
1
0.63
10
2.5
1.56
Onsite Area 3
Pt. B+3
1
0.3
1
0.30
10
2.5
0.75
Pt. 13+3
3.5
0.26
1
(
0.91
10
2.5
2.28 Flow at 'minor' ravine at north central area
Offsite Area "C'
Pt. C
4.5
5
1
1.13
10
2.5
2.81
Onsite Area 4
Pt. C+4
1
0.3
1
0.30
10
2.5
0.75
Pt. C+4
5.5
0.2
1
1.43
10
2.5
3.58 Flow from north and west- add 30 c.f.s. irrig
33.60 Total with Irrigation flow
Onsite Area 6
Pt. 6
1
0.3
0.
10
2.5
0.75
Total at Ravine
Pt. B+C+6
10
0.2
�
t
15
2.1
5.46 Flow exiting site - add 30 c.f.s. Irrig.
35.50 Total with irrigation flow
Onsite Area 2
Pt. 2
1
0.3
0.30 I
10
2.5
0.75 Flow to south offsite overland
Onsite Area 5
Pt. 5
1
0.
1
0.30
1
2.5
0.75 Flow to south offsite to 'major' ravine
Calculated By:
DRM
STORM DRAINAGE INVESTIGATION
# 1180-01-01-02
Client : Dr. Musslewhite
Date : Dec. 29, 1989
RATIONAL
METHOD PROCEDURE
Project: SHIELDS STREET PROPERTY
Checked By:
KWP
Design Storm: 1 W R -Developed onditions
Location
Point
Area
Runoff Coeff. Freq. Factor AxCxCf Flow Time
ow Time
Rain Intens.
Runoff Commdrtts
Description
Designation
(acres)
C.
'cf.
Tchan(min.)
Tc (min.)
'I'(in./hr.)'O'(c.f.s.)
Offsite Area 'A'
Pt. A
10.5
0.2
1.25
2.63
6
15.75
Onsite Area 1
Pt. A+1
2
0.5
1.25
1.25
20
5.15
6.44
Pt. A+1
12.5
0.25
1.25
3.91
20
5.15
20.12 Flow at west side of Shields flowing to south
0=20 cfs for Culvert sizing
Offsite Area 'B'
Pt. B
2.5
0.25
1.25
0.78
1 0
7
5.47
Onsite Area 3
Pt. B+3
1
0.3
1.25
0.38
1 0
7
2.63
Pt. B+3
3.5
0.26
1.25
1.14
1 0
7
7.96 Flow at 'minor' ravine at north central area
Offsite Area 'C'
Pt. C
4.5
0.25
1.25
1.41
1 0
7
9.84
Onsite Area 4
Pt. C+4
1
0.3
1.25
0.38
10
7
2.63
Pt. C+4
5.5
0.26
1.25
1.79
1 0
7
12.51 Flow from north and west- add 30 c.f.s. Irrig
42.50 Total with irrigation flow
Onsite Area 6
Pt. 6
1
0.3
1.25
0.38
1 0
7
2.63
Total at Ravine
Pt. B+C+6
10
0.26
1.25
3.25
1 5
6
19.50 Flow exiting site - add 30 c.f.s. Irrig.
49.50 Total with irrigation flow
Onsite Area 2
Pt 2
1
0.3
1.25
0.38
1 0
7
2.63 Flow to south offsite overland
I
Onsite Area 5
Pt 5
1
0.3
1.25
0.38
1 0
7
2.63 Flow to south offsite to 'major' ravine
Page 2
I
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SHEET INDEX_
i I.AK
116 fiNhL BITE 1�r'.I�L
L 6 FpUNji/CT�TI PWI.L
3 6 Fipp� N
5 � ELfL�%rV, W'IN
a G WL4i ANN CXL FL,4N
FIWL 5rrf- FLAN
I A I Fj"l_ ��TE P,JIu
LAriD�CAPE T'LAN
(� I IhNDka� fL#I
VTILI-fY fLHNS
I'g- NDGX,VIGIKjjTY Md,p> IMt_ `4tff7
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F 4 VTLl7r 13A14
9 4 j7ErPdLC
PLA7, �U�� �/�IV�IN
101 LgUF4E 7UF FIR`T PILING
final Plan
statement of plantains OY
no proposed Veterinary Clinic is O distant 1OT
located le orate . can ..Dahl r. y a people
. dale:odd to t uvael•to character oa Will GaWLt nt
tine ding be Use. a
statement of proposed Ownership rtalp Of Public and Private Open
$.ceIZ OIL oPev Psce 'III a Prlvv Open ,part and maintained
by the near.
estimate Of Number of employees fat Business no eat mate for
the nu er Of employees four
no Duet,ptdOn of pR(optl• The veterinorY Ctecf= was designed
nutfui the vva, c he ovvvr and be a deafrole ,n: m9
virobvbt for people utlll,tug the services a a veterinary
The Pilot" anlava„apme Is deaipva pP,a,
desirable from the wields street art risl.
Description of eft,9=tlev of Land US, C onflictu The veterinary
Clinic in assigns o be residentialIn character. Laamaplo9
is propnetd s1 oddonmm bidder .amg aides Of ehramie.
essential of Barney dareavytf®: The Veterinary Cl:mt Will be
aetfgmd ath an ...lobo, ,yetes that Will be "Ole the area.
rtw round provides n the building Its
air=
LOf SIZE: u,:c7'5Prr
d LI Pr
EEXUA1
FLCEPIIOAI
tan
Gras-. CAT ft1113EL5
I9Z5iC?
pImL
den sa K
FA¢FINd a`fp�-
(th z7cts
FINAL SITE PLAN
/LOT 5, UFIE "'L i L9` IcN FlPi7r flLJN 6_.
I 4 M N[ k , 6
Out 4 _
,#l r-�WSv .D Fo>fi
I
PLANNING AND ZONING
CERTIFICATION
'Approved by the Planning and Zoning Board Of the
City Of Fort Collins. Colorado, on th's_day
lof A.D. 1990
SeC[eta[y OI Planning antl Zoning Board
OWNER CERTIFICATION
The understanding, being the lawful owners Of the property
described on this site plan, do hereby certify that they
accept the Condition and restrictions set forth on said
site plan.
(signed)
THIS IS TO CERTIFY THAT ON THE DAY OF
19 . I EXAMINED THE TITLE TO THE PROPERTY AS DESCRIBED
HEREON AND ESTABLISHED THAT THE: DRNERS AND PROPRIETORS
OF RECORD OF THE SAID PROPERTY AS CONSTRUED IN C.R.S.
1973, 31-23-I11, ARE AS SHORN HEREON AS OF SAID DATE.
REGISTRATION NO.
�2a
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