HomeMy WebLinkAboutGrading Plans - 05/26/2020%J
Fetzer Engineering, LLC
May 22, 2020
Mr. Diane Reiser
412 Wood St
Fort Collins, CO 80521
RE: Drainage Memo
for 412 Wood St, Fort Collins, CO
Dear Diane Reiser;
Grading/Stormwater Plan Accepted
(Building Permit Released)
Accepted by: Dan Mogen
Date: 05/26/2020
Lot 21 Blk 294 West Side
B2001541
Attached is a grading plan showing the location of your proposed garage and the grading around this
future residential site improvement. Drainage calcs for capturing additional storm flows that this rooftop
will generate are also attached. A topographic survey was obtained by Colorado Licensed Land Surveyor
to facilitate this effort. Small swales have been strategically placed to route stormwater away from the
house and garage and towards the east portion of the lot where storm flows are captured into a proposed
rock sump pit which is intended to infiltrate into the ground. All planned downspouts of the garage are
located towards these swales which flow utilizing standard residential spouting to a splash block which
empties into these swales. As a result of installing and routing runoff from the garage to the infiltration
sump, runoff from this garage building is effectively mitigated and no adverse impacts to adjacent
properties are anticipated. Rock sump has been sized per Fort Collins Drainage Manual criteria. Please
refer any questions to myself at the contact information provided below. Thank you
Shawn Fetzer, P.E.
ti�r��
�DO L/���rr�.
''NNEr �ysFr11
� ,y ti p .
r,..— � .,...
S - :�
�
+f� �.�'�'�'•••.....• ••'G��,� `
.�., �..S/ONAI.EN y=�
5/22/2020
Disclaimer:
This document, together with the concepts and recommendations presented herein, as an instrument of service, is
intended only for the specific purpose and client for which it was prepared. Reuse of and improper reliance on
this document without written authorization from Fetzer Engineering LLC shall be without liability to Fetzer
Engineering LLC
1768 Twin Lakes Cir, Loveland (970) 702-4884
412 Wood St, Fort Collins Detention Calcs
Modified FAA Procedure - Assuming Storing Additional Post 100 yr Flows from 600 SF Garage Only
Proposed Existing
Time 100 Year 100 Year
Duration Cproposed** I* A(ac) Q(cfc) V(cf) �ex;scmg�• I* A(ac) C1(cfs) V(cf)
5 0.95 9.95 0.01 0.130 39.133 0.50 9.95 0.01 0.069 20.597
10 0.95 7.72 0.01 0.101 60.726 0.50 7.72 0.01 0.053 31.961
15 0.95 6.52 0.01 0.085 76.929 0.50 6.52 0.01 0.045 40.489
20 0.95 5.60 0.01 0.073 88.099 0.50 5.60 0.01 0.039 46.368
25 0.95 4.98 0.01 0.065 97.932 0.50 4.98 0.01 0.034 51.543
30 0.95 4.52 0.01 0.059 106.663 0.50 4.52 0.01 0.031 56.138
35 0.95 4.08 0.01 0.053 112326 0.50 4.08 0.01 0.028 59.119
40 0.95 3.74 0.01 0.049 117.675 0.50 3.74 0.01 0.026 61.934
45 0.95 3.46 0.01 0.045 122.474 0.50 3.46 0.01 0.024 64.460
50 0.95 3.23 0.01 0.042 127.036 0.50 3.23 0.01 0.022 66.861
55 0.95 3.03 0.01 0.040 131.087 0.50 3.03 0.01 0.021 68.993
60 0.95 2.86 0.01 0.037 134.981 0.50 2.86 0.01 0.020 71.042
65 0.95 2.71 0.01 0.036 138.560 0.50 2.71 0.01 0.019 72.926
70 0.95 2.59 0.01 0.034 142.611 0.50 2.59 0.01 0.018 75.058
75 0.95 2.48 0.01 0.033 146.308 0.50 2.48 0.01 0.017 77.004
80 0.95 2.38 0.01 0.031 149.769 0.50 2.38 0.01 0.016 78.826
85 0.95 2.29 0.01 0.030 153.112 0.50 2.29 0.01 0.016 80.585
90 0.95 2.21 0.01 0.029 156.455 0.50 2.21 0.01 0.015 82.345
95 0.95 2.13 0.01 0.028 159.169 0.50 2.13 0.01 0.015 83.773
100 0.95 2.06 0.01 0.027 162.040 0.50 2.06 0.01 0.014 85.284
105 0.95 2.00 0.01 0.026 165.186 0.50 2.00 0.01 0.014 86.940
110 0.95 1.94 0.01 0.025 167.860 0.50 1.94 0.01 0.013 88.348
115 0.95 1.88 0.01 0.025 170.063 0.50 1.88 0.01 0.013 89.507
120 0.95 1.84 0.01 0.024 173.681 0.50 1.84 0.01 0.013 91.411
` Rainfall Intensity per Table 3.4.1 of Fort Collins Drainage Manual
** C-values are based on Table 3.2.2 in the FC Drainage Manual. Proposed surface is a Rooftop at 0.95 and Existing is gravel at 0.50
Total Detention Required = 82.270 CF
Detainage Rock Sump Size
Width 5 FT
Length 14 FT
Depth 5 FT
Void % 25%
87.5 CF
O
3
SIREET -
CURB
RAISE'SIpEWALN 3"
IN FRONT OF PORCH
EXi511NG J i
SIDEWALK I
l..
REPLACE SIOEWALK
PRON�E POSITIVE DRAINAGE
BREAKPOINi
PftOPOSED ROOF GUTiER
OOWNSPOUT LOCAiION
�.aa-���=��.�,.� I�--.. —v-�.—�—�.—. �Y -
i �
�__,__� �
EXISTNG
EXISIING BIIILDING �ECN
(850 SF) (400 Sf)
E%ISIING
BREAKPOINT SIpEWALK
(]0 SF)
PROPOSED ROOF GUTiER
SPLASH BLOCK LOCPTON
�RAINAGE SWHLE,
6" DEP1H
r—�.. �—��—r=� ���.�.__
18.15 —
EXISTING 6 � R
SHE� � L1
���a 5F� �
�, ��. �-�.��.�.J
� g3' �_ �,��
�� �
I I � � 6" P� PIPE M
t `/y—v��r.a nr�rx�l�'.� L���
PftOPOSED ROOF GUTIER ` DRAINAGE SWALE, FlNELY CRl15HE0 ROCK
DOWNSPOUT LOCATON fi" pEPRi PATH, 4' YAOE (285 SF)
REMOVE
EXISnNG
FENCING
BUILDING
oN -soozza
PROPOSED ROOF GUTIER
SPL45H BLOCK LOCATION
5' X 14' R-4 RIPRNP ROCK PIT,
5' �EPT1, COVER WIiH fi" CLA55 5 ABC
TOP ELEVATION = 5006.50
ROCK � i I
SUMP }
I
�
zo' � i
� � Q r
� � ��
NOTES
1. PROPOSED SLOPES SHALL 9E NO STEEPER h1AN 4:1
2. ALL ORAINAGE SWALES NEAR iHE HOME ARE NOT RE�UIRE BUT REDUESIED BY iHE ONNER TO AID iN DRAINING hiE
AREAS AROUND iHE HOUSE AND NEAR THE PROPOSED ALL WEAh1ER CRUSHED AGGRECATE WhLKWAY
3.lHE IIIILIilES SHOWN HEREON ARE FROM VISIBLE SURFACE EVI�ENCE AN� FROM R1E UIILIiV LOCAlES. THERE MAV BE
/ BIIRIEp UTIIJPES ON OR A�JACENT i0 RilS PROPERTY 1HAT ARE NOT SHOWN �UE TO INSl1FFICIENT SIIRFACE EN�ENCE.
NO STFIEMENT IS MADE CONCERNING SUBSURFhCE CONOIilONS OR h1E E%ISTENCE Of OVERHEAp OR UNDEFGROIIND
, CONTAINERS OR FAqlI11E5 WHICH MAY AFFECT iHE �EVELOPMENT OF iH15 SIIE.
GRApING PLAN FOR 412 W00� ST EXISiING IMPERVIOUS AREA:
9l1IL01NG PERMIT �y92001561 EXISiING HOUSE - 850 SF
CONTACTINFORMATON EXISPNG �ECK - 400 SF
KIIOW WheYsbQIOW. NAME SHAWN FETZER EXISPNG SHE� - 100 SF
C.B��beforeyoudig. nooaess: nea rvnH �nKes aa exisnNc sioewnu� - isa sF
PHONE NO.: 9J0-�02-4984
EMAIL AOpRE55: NEW IMPERVIOUS hREA
SFETZER¢fERERENGINEERING.COM GARAGE - 600 SF
LEGEND
—___— LOT LINE
� E%ISTING SIOEWALK
� PROPOSE� SIDEWALK
� EXISTING �ECK
O E%ISiING BUILpINGS
� PROPOSED GARAGE
PROPOSED ROCK SUMP
1 I ,1
��_
U
.a
a
04 �
�
.�
�m �
'04 �
W o�
N ry��
w °a�
z
Q
�
�
�
z
0
�
�
�
(/7
� Z
��
O J
� O
� U
�
N �
� Q
� �
pQ,pDO LICF,�s
VO�:�ENNETy•.FQ
�Q�9� �'�
9�1, i2^_2�,��
E'rS/ONPIENV�