HomeMy WebLinkAboutLot Certifications - 10/23/2015Lat�, 9 J to, 73tIc. t3, Cv-aCfS , FT c
NORTHERN 1315os-334-
ENGINEERING
Drainage Memo
Date: October 23, 2015
Project: 612 Pitkin Street Project No. 1199-001
Fort Collins, CO l
Attn: Stormwater Staff
City of Fort Collins Stormwater Utility 1
700 WoodStreet
Fort Collins, CO 80521
Stormwater Staff:
This letter serves to document the proposed drainage impacts of a new home proposed at 612 East
Pitkin Street in Fort Collins, Colorado.
Project Overview
The project as currently envisioned proposes to completely remove an existing 2-story home located
on the property and construct a new home as well as a carriage house that will be accessed from
the alley on the north side of the property. -
Existing Site
The existing site functions as a "B" Lot, with drainage from the lot draining from the home out to
the side lot lines, which then convey the drainage to both the front and back of the lot. Existing
grades in the front yard range between 2%-4%, and grades in the back of the home vary between
1% and 2%. In addition to the existing home, the lot consists of a concrete driveway, concrete
entry walk and concrete porches around the entire home. The remainder of the site is Kentucky
Bluegrass lawn, with small. landscaping beds and mature trees.
The total existing impervious area for the lot is 5,305 sf.
Proposed Site
The proposed site will continue to function as a 'B' Lot, with drainage from the new residence being
directed to the side lot lines, and then to both the front and back of the lot via existing "swales"
along the lot line. Existing grades outside of our improvements will remain unchanged, including
along the east side of the property where no improvements are proposed. Modifications to the
existing driveway and front entry walk are proposed with the new home, and a new carriage house
is proposed at the alley that will have a small concrete apron at the entrance.
The total proposed impervious area for the lot is 6,042 sf. This is an increase of 737 sf. The
increase in runoff as a result of this will be negligible, and no adverse impacts to adjacent properties
is anticipated.
301 N. Howes Street, Suite 100, Fort Collins, CO 80521 I 970.221.4158 I www.northernengineering.com
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Detention
Since the impervious area increases less than 1000 sf, no' detention is required for the site. .
Water Quality 4
Water Quality for the site is being.provided by releasing concentrated flows from the roof into
landscaped areas that allow stormwater runoff to infiltrate surround soils. Stormwater that is
unable. to infiltrate is slowly passed through vegetated areas, further removing stormwater
contaminates before stormwater leaves the property.
An, exhibit has been provided to illustrate the existing and proposed impervious areas. Please feel
free to contact us if you have any questions.
Sincerely,
Andrew Reese
Project Engineering .
io.z3.1
Nicholas W. Haws, PE, LEED AP
Vice President
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LEGEND:
PROPOSED CONTOUR
-91
BASTING COMONR
----:Ai�----
PROPERTY BOUNDARY
r I PROPOSE. SPOT ELEVATION %
I EYJBTINc sPOr ¢EVAnon i�
PROPOSED SLOPES 2_Ox
NOTES:
1. THE SZE. TYPE AND LOCATION OF ALL XNOWN IMOERGROUND UTILITIES ARE
APPROALATE WIZEN SHOVEIW H ON THESE "WEDS. IT SL BE THE
RESPDXSIdUT' OF ME CONTRACTOR TO VERIFY THE EXISTENCE BE AL
UNCERGROUNDUBUTEESINTHEAREAOFMEWORK, BEFORECOMMENONG
XEW CONSTRUCTION. THE CONTMCTORSIWLBE RESPONSIBLE FOR LOCATING
ALL UXDERGR W NB URYDSB ME SHALL BE RESPONSIBLE FOR FOR Nl
UNEROWN UNDERGROUND UTN7NE9.
2 REFERTO THE RAT FOR LOTAREINI TMCTSIMS. EASEMENTS. LOT DILFNSIONS,
UMITV EASEMENTS, OTNER FASEAENT8 AM OMER SURVEY INFORMATION
S THECONTRACTOR9HA-L,ATNLnMESOURINGANBAFIERSYSTEM
LLp IXSTAATN, PREVEM MENUENT, DENNIS. AND DIRTFRG.I INN SOURCE FROM
ENTERING ME PERMFAAE PAVEMENT SYSTEM LOOSE MATEWALS SIWL MT DE
STDRED ON THE PERMFPBLE RAVEMENTAREA. MUD MI MINUENT.."
RUHOFFSIIWLC BE NERT AWAY FRCA THE PAVEMENTAREA TEMPOEVI
ONEATRUNOFFORINSTMLSMB NTC IRMMLLg1IRF NFSESSMLYTO
REDUCE THE MOUNT OF SENHEM RUNAN TO THE PAVEMENT, SURFACE
IH OTECTION COULD INCLUDE COVERING AREAS BE THE PAVEMENT, PROVIDING
ALTERNATIVE CONSTRUCTOR V&ECIE ACCESS. AND PR(A DIINO EDUCATION TO
ALL PARTIES WOIWNG W IR E
A THE CONTRACTOR SHOULD CONSIDER RACING THE'hEARING CWRBQ AMR
FINEG INOANDLANDSCARMOINApN TNi MCOLBLETE. IETE
VIEWING COARSE BECOMES CLOGGED DUE TO CONSTRUCTION ACTNTEES.
DUSAN THE SURFACE WRHA VACUUM M4CHINE M RESTORE THE INFLTMTION
RATE AFTER CONSTRUCTON IS COMPLETE.
1 BFSEBIDRAVER98HALL6EFI MVEBYBORGEMMMUCTS. BEFAIAT
LAVINGPA7
ERNSHALLBE4VHERRNCBONEOU HANUNCMSNLMOR
SIXDIER COURSE ALONG THE ENTIRE PETOIETER CBNFNOI PAVER TYPE, AIL OR.
AND PATTERN Y RK DINNER AND LMNSUFE MCKTECT PRIOR TO EURCHMES;
B AL CUT PAVERS USED MAST BE AT LEAST ADY BE THEIR FALL UNCUT SUE.
PROJECT BENCHMARKS:
PROJECT DATUMHAVE SE
CITY OF FORT COLLINS BENCH MINK WR
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City of Fort Collins, Colorado
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