HomeMy WebLinkAboutDrainage Reports - 08/09/1993ca?Pei 2
STORM DRAINAGE REPORT
FOR
BROOKS MINOR SUBDIVISION
AUGUST 9, 1993.
STEWART & ASSOCIATES, INC.
103 SOUTH MELDRUM STREET
FORT COLLINS, COLORADO 80521
303/482-9331
STEWART&ASSOCIATES
Consulting Engineers and Surveyors
August 9, 1993
Mr. Glen Schlueter
Storm Water Utility
City of Fort Collins
P.O. Box 580
Fort Collins, Colorado 80522
Dear Glen:
The following is the storm drainage report for Brooks Minor Subdivision
located at 900 North College Avenue. The site contains 2.507 acres and is
situate in the Southwest '—a of Section 1, Township 7 North, Range 69 West of
the 6th P.M., Fort Collins, Colorado. The site is a part of the Dry Creek
Drainage Basin.
The minor subdivision has two lots. Lot 1 was an existing parcel
containing 0.85 acres which has an existing building which was formerly a sign
business. The property is changing use and is proposed to be a bingo business.
A parking lot is proposed for Lot 2 which contains 1.66 acres. The east 200.00
feet of Lot 2 will have the asphalt parking lot, and the west 190.00.feet will
remain undeveloped at this time. Phase I of the parking lot will be the south
138 feet thereof.
The lot slopes from College Avenue easterly at approximately 0.6% slope.
The existing drainage pattern is sheet flow easterly to the east line where
it is blocked by the berm of an existing waste irrigation water ditch.
The only offsite storm water entering this project is sheet flowing off
of the existing hair salon and used car businesses that are adjacent on the
west line of the north 176.70 feet of the propsed parking lot. During the
time when only Phase I of the parking lot is built, the offsite flows will
continue to sheet flow onto the undeveloped Phase II parking area. After Phase
II of the parking lot is -completed, the offsite flows wil be directed southerly
along the back side of the west curb of the parking lot to a slot in the north
curb of the driveway. In both the detention condition and the retention
condition, the offsite flows are allowed to drain across the site; but the
offsite flows were not included in the calculation of the required detention
or reteniton volumes.
.The long—term proposal is to use the existing berm along the east property
line to create a detention pond on the proposed parking lot. The difference
between the two—year historic runoff and the 100—year developed runoff will
be detained. The required volume is 17,370 cubic feet, and the allowable
discharge rate is 1.73 cubic feet per second. An 8—inch diameter outlet pipe
will be placed through the existing berm as a discharge pipe into the existing
waste irrigation water ditch along the east property line. The actual volume
provided is 18,210 cubic feet.
James H. Stewart
and Associates, Inc.
103 S. Meldrum Street
P.O. Box 429
Ft. Collins, CO 80522
303/482-9331
Fax 303/482-9382
Brooks Minor Subdivision — Page 2
The existing waste irrigation water ditch flows south adjacent to the
rear of the existing businesses to the north side of the Lake Canal. The waste
water ditch then turns easterly and follows the Lake Canal to its intersection
with Dry Creek. The ditch is located on the property with the existing alfalfa.
There are several field laterals which are not in use at this time. The laterals
run south from the irrigation ditch along the north side of the alfalfa field.
The supply ditch has not run water for several years. The pipe from College
Avenue easterly is badly silted in.
Due to timing in acquiring a drainage easement for the existing waste
irrigation water ditch, a temporary retention pond for the runoff from the
first phase of the new parking area was proposed to the Storm Water Utility.
The runoff will continue to flow easterly to the existing berm along the east
property line as planned for the above described detention pond. However,
the outlet pipe will not be constructed until the downstream easement is
granted. The retention pond will have a capacity of two times the volume.of
stormwater generated by the 100—year storm, which is 46,224 cubic feet.
The required retention volume will be restricted to the owner's property
and will not encroach on any adjacent property nor on the existing building.
At the time the downstream drainage easement is acquired, the discharge
pipe will be constructed, and the 18,210 cubic foot detention pond would be
used. Since the retention pond is only for the first phase of the paving,
a modified drainage report would be required if the owner wanted to construct
the second phase of the parking lot.
EROSION CONTROL:
The site is in a moderate wind erodibility zone and in a moderate rainfall
erodibility zone. Lot 1, containing 0.85 acres, is completely hard surfaced
and so is not included in.the erosion control effectiveness calculations.
Lot 2 will be stripped off and graded and then the base material installed
immediately after the grading is completed. The asphalt paving will then be
installed.
Straw bales will be placed at the outlet pipe of the detention pond and
remain in place until the base material is completed, and then a rock filter
will be placed on the out pipe to provide a sedimentation basin. The rock
filter will remain in place until the landscaping is completed.
The erosion control plan for the short—term scheme is the fact that the
retention basin will be a sedimentation basin because there will be no
discharge. There will be no sediment leaving the property.
The runoff calculations, mass diagram and erosion control calculations
and the drainage and grading plan are enclosed as a part of this report. If
you have any questions regarding this project, please.call.
Sincerely,
6 2,�, Ct
Richard A. Rutherford, P.E. & L.S.
President
jrr
enclosures
5028
STEWART&kSSOCIATES
Consulting Engineers and Surveyors
103 S. MELDRUM, FORT COLLINS, CO 80521
PH. 482-9331 FAX 482-9382
By: R A Date: (,193Jf J Client: A.0,C.. Jin.) 3 of
Project: 'R 2. 0,9 - I A4 / v n /a, Su g,r> , y u lo
Subject: S -ro r— M GU A -F F, t-- P L, /J 0 -,c- C C, A L. C u t—,!) /U r
o
0.•t,,7
A
1'r T.;
- V 0 U
!AREA.
gases.
3 e, I
F— V to VJ E' A
q 7,
A C.
I
&-7 C Z, '6 3 F-
0.4-9
Tit •Z-;
ix': J
77
S,
10Y x
/00 y ei "Tc
4 3 0
�-- . Z-3 m 't).
I I Je 1x; 2-677 -7 - 8 7
! ! 1 1 1 ; I ( :- - / 2,5- x 40, 4
STEWART&OSSOCIATES 103 S. MELDRUM, FORT COLLINS, CO 80521
PH. 482-9331 FAX 482-9382
Consulting Engineers and Surveyors
By: Date:_ 6h:>Client: A, t3, c. J Sheet No. ^ of
Project: T) 'r AA V 'r. r> I U I P r A/
Subject: F rip nn U) 7 it e P, U 'V O'c F F0 A 7L
+! �
),t71A 0 L'LCC-C-
T"
I I A Ie F_ A
/IL, I
717, 0
p ic je 'J t)j
A tf, G Al
'ii��
7L 14
�i_ ±jlj'I
10
7, 6.
4 3o
Vz- 12, M
t 11
tY4
3 z x
&-7 7
0 Y'cl
018
7
T_C_
.4- 3 o
5. V,
linoY
C.
Z8 660 -
Z+000 -
Zd
14000-
12,000 1
MOTO mo
+000 1
STEWART&ASSOCIATES 103 S. MEL933DR1FAXUM, FORT COLLINS, CO 80521
PH. 482-482-9382
Consulting Engineers and Surveyors
By: PAP. Date: Client: A.R.C, Sinw Pp*onvc-r 77(,, Sheet No. S- of
Project: P, M I,vnv- fu P. r-, i yz r /� j
Subject: AA c T) t
T
C A
A —I -Z,;�x 01,004x.a-6*7-7
4, 115-1
("0
3
80
90 i /.4" 6.
11861.
Qo
-- I--[
- 3- -
?,7
/0)
/6170 q-'
3 4 o
R01
37
ZZ, I be,
S. 03 I
24,090
18, 16 0 -r-
17 4,
7
S, 4-9
bq(l
?-'71S 47
13, 3177'
Or
1)
0 to -Lo 30 4-0 j-0 & 0 7o
0
STEV VART&ASSOCIATES 103 PH. S. MEL9 3DIRFAXFORT gOLLINS, CO80521
Consulting Engineers and Surveyors
By: A P Date: 6Z?-31 q9 Client: A.B. G. flGiv PleoovLr� ZNgSheet No. (.o of
Project: T) e oo KJ Jj�i A/ n 2 r,l B D 1 ✓,.r, e.) ti
Subject: F) 4 r— A, T io Aj Ec-) r> D u H A e. r, 6
�IFIG�r✓; � i .i � I ' '
197 c_. r,Y ti = / o
0
k/ 0,G 1,'f�4x1 /.o(I ! ¢,9G Fr/rcc.
V /4
1 - , 1 - I U 3 97 Fr-
i
I � � UJEI S! tPiVrC' + OvYI LE`r
1 GxiST)iU177TGh' CAPAc, .7—
!
lC9 3 I !
iil i III ll�
,
r
k 7--93jx1 z"y3'� /?:v'C bOLG) Z
,
STEWART&ASSOCIATES
Consulting Engineers and Surveyors
103 S. MELDRUM, FORT COLLINS, CO 80521
PH. 482-9331 FAX 482-9382
By: p A Date: 7/js/93 Client: A.F,n Sl,-,.v P1ep1),1e7uJ-Ai,. Sheet No. -7 of_
Project: o 0 .4:: -1 U 0 r1i p ?� /V t, r (6 .0
Subject: o I? /'.I A 2-e-1 17-1 R UA,14r-r- -T- /%vl,,
A S:0 -7 A�cl
Je
DGV --zv:10 s A I A 5"3. z %
O. 532 4+ �6, 'S 4-6 C. &5-
0,
D;E7 C- V-6 5
3 1?
P &V - z Yk (0 x l DI Z )( 1 2 s-0 J.
-2-, SO 01. 6: f� 3 .'Z x
It
Lq
-X 3461
b 2, 5- X 0 - 4 5-: /Y -N 7 0 -
NVY-rd 241 Q = /I Zsix '0, 6 1;- x 2.3-071
2 - 4- K V 8'0 :,x 6 0
PC-'/; G A0 7 C 0 -F'G,4J.L) V& LL) A I I- Em r.
STEWART&ASSOCIATES
Consulting Engineers and Surveyors
103 S. MELDRUM, FORT COLLINS, CO 80521
PH. 482-9331 FAX 482-9382
By: P .4 P Date: V z � / 9 3 Client: A . -9, G, T , e- ti -P2 o D vc T.f .Tej Sheet No. 8 of
Project: P- on c s All z ,v e e ry P, r:> t v t, r i o Al
Subject: n F F - LE1) )e M U) A T r, k-, A;' C v t, A r ia.vs
M P,�1ZV.to,U1 �i R Ufa; 0,5 8 '4u,%•
PERivtov.rj Arz�c-a -' �0'`!`� Ate'. Z4.7!o
C. = CI x 0,7331 `0,'LSx G•. L4-0. S
iy
I- I
-7
j II!iIIIII ' ;
DEV, QZy� I-' C18z X Z.�9 i X o•77' _! %,8'3� c..F,,J,
(' ( i
.; iti��.IIICI!ii
I I DF- • IQroye = U•�ZJ!Al SD x 0,771 =� 3• /� !c.Fs;
loo ye 'Tc /• $7!�l. J�- (l2sxo.gti19o'�ZI
i II, iY3;
i I DEv 'Qiloo y/e �;I /:7-5 a-8z.! X %.z X 0.77' ,5.54 c.F,s.
STEWART&ASSOCIATES 103 S. MEL9331, DRUM, FORT COLLINS, CO 80521
PH. 482-FAX 482-9382
Consulting Engineers and Surveyors
BY: P- A e, Date: 7/?-.3 Client: A - 6. C - Yt &A) Pg o r> w -,r r- -rA . Sheet No. of
T-
Project: F U L- tit, v r I IU n A! P� b I V I C / 0
Subject: P -, v o r- r-- C-A t r u) L q 7- / oxi s Fp--o m j /1L) 7)r-,v a (- o p i:-p PA re 7-
STEWART& SSOCIATES 10 a31 . ME DRUM, FAX 482 T COLLINS, CO 80521
PH.82
Consulting Engineers and Surveyors
By: A 2 Date:R/q / /-73 Client: A. S. C. S raw Pin nvcz-s.z"ni,.Sheet No. /0 of
Project: }3 1Z 0rn •t. i All/ Al 0 /L f v r3 n I Li 1 r 10 n/
Subject: Cot-t_Ei��: er—:7, Avg. 2v,v6,C7r—,
i I I p,PEA( i �.l•7'Ac, A1JuMc G= 0:9S
t I
�_ 47.8?(1.1-0 9s�19o.Vz- !
i
! i ( 0,3
QZye. 'o.957x;3.io;x: 0•/7 4.4-8
G ,q !o�
e - O i9 n S Zix 0,/7 p, 8 ¢ c-,F,s.
i I
/oo TG
! ; ;Q100Xw-1 =! /ZSix p,ySx 7.Z x D,/7'
1
I ;
;
Ad
RAINFALL PERFORMANCE.STANDARD EVALUATION
PROJECT: ZP-bokr Miwoie. Sveoovuio-v STANDARD FORM A
COMPLETED BY: DATE: Jum Z9, itg3
------------------ -------
--------------------- ------------e---
IDEVERODIBILITY Asb Lsb Ssb Lb Sb PS
SUBBASIN ZONE I (ac) (ft) (%) (feet) (%) (;)
-----------=-----------
Z07 /,I,( . 34o D-(-% 39 o D.G/o i 73.5%
------------------------------
DI/SF-A:1989
EFFECTIVENESS CALCULATIONS
PROJECT: BQook•d M,4,01Z, 3v13pjvt.r1op STAIIUARU FORM B
COMPLEIEU BY: R-A-e— DAIE: Juue z9,�9��
Erosion Control
C-Factor
P-Factor
Method
--------------------
Value
Value Comment
�.X�1T/A1G GKq�EG.
--------------
O.(o
/---------- ----------
6.36 Ae,
A -r P P4 A L- 7-
0, 01
/, 00 /. / 1 A c.
BA,z.c— Gre- ov.UD
/.o
/.00
Sre,4w BASES
/10
0.80
Gz,n✓EL FlLTEC
AD �
0•BO
AS ,('ED IMENT -FRAP
-----------------------------------------------------
MAJOR PS. SUB AREA
BASIN (o) BASIN (Ac)
CALCULATIONS
--- ------
Z
------ ------------------------
uII..D C
3GX 0.10)1-X 0.p1)
6,ra3 •
wTo
(0,)43x0, 0yjx l°c
ok. % 73•S%
----------------------------------------------------------------------I
HDI/SF-8:1989
CONSTRUCTION SEQUENCE
PROJECT: • BP-ookr M)Aine- Sum -pull -rip
STANDARD FORM C
SEQUENCE. FOR 19 93 ONLY COMPLETED BY: ' - R. A- P, DATE: Jr/,ye 29,i993
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 I
MONTH. -- -- I I M I
I -- -I--!-- - ----- J
OVERLOT GRADING II
WIND EROSION CONTROL
Soil Roughing
Perimeter Barrier
Additional Barriers
Vegetative Methods
Soil Sealant
Other
RAINFALL EROSION CONTROL
STRUCTURAL:
Sediment Trap/Basin
Inlet Filters
Straw Barriers
Silt Fence Barriers
Sand Bags
Bare Soil Preparation
Contour Furrows
Terracing
Asphalt/Concrete Paving
Other
VEGETATIVE:
Permanent Seed Planting
Mulching/Sealant
Temporary Seed Planting
Sod Installation
Nettings/Mats/Blankets
Other
----------------------------------------------------------;- -
STRUCTURES: INSTALLED BY MAINTAINED BY
VEGETATION/MULCHING CONTRACTOR
DATE SUBMITTED APPROVED BY CITY OF FORT COLLINS ON
HOI/SF-C:1989