HomeMy WebLinkAboutLLA91-00008-0307/10/97 ~0:30
452 8498
NTI ENG.& SURVEY
NORTHWESTERN TERRITORIES, INC.
EnUresis · Land Su~e-~rs ~l Planners
ConsrruCl(On COordlnal~on Ill Ma~als 7~ing
July 10, 1.997
~ 001
via F~
JEFFERSON COUNTY
PO BOX 2070
PORT TOWNSEND WA
98368
ATTENTION:
Re:
JIM PEARSON: PUBLIC WORKS DEPARTMENT (360) 385-9172
JERRY SMITH: PLANNING DEPARTMENT (360) 379-4451
Quilcene Heights Subdivision - Drainage Report Elements
to be recorded with the County Auditor
Dear Jim and Jerry:
Attached are five (5) pages of instructions and reference
charts/graphs for the design/selection of the on-site drainage
facilities. Please look at this package to make sure that it meets
the intent of Jim's 5-9-97 letter (bottom of page
If you have any questions or commen~s, please don't hesitate to
contact me.
Sincerely,
NORTHWESTERN TERRITORIES, INC.
Robert A. Lea~
Senior Engineer
c:
Christopher Sharp
Pat Burke
LOG iTEM
717 SOUTH PEABODY, PORT ANGELES, WA g8362 (360) 452-8491
1480~4-55~5
FAX 452-8498
07/'10/97 10:32
'~360 452 8498 NTI ENG.& SURYEY
NORTHWESTERN TERRITORIES, INC,
Engineer's I Land Sur~c~/ors [] Planners
~002
QUILCENE HEIGHTS - INDIVIDUAL LOT DRAINAGE CONTROL
An Engineered drainage concept with standard designs for individual
on-site drainage control devices has been prepared by a Licensed
Civil Engineer and approved by the County. Individual property
owners will De required to install either the facilities described
herein or an equivalent alterna%ive facility designed by a Licensed
Engineer.
The following process is to be used to size the on-site facility.
Determine the total square feet of impervious surface to
~nterpolate values from ~h~ following charts and graphs,
In the event that the total impervious surface is less
than 2000 SF or greater than 4000 SF, extrapolate from
the 3000 SF value.
Refer tO the "Qullcene Heights, Detention Tank Size
selection Graph" to de~ermine the i~'ternal length of the
standard cros~-section tank.
Refer tQ the "Qullcene Heights, Orifice Size Selection
Graph" to determine the elevation and size of the control
release orifices to be ~nstalled. All elevations shown
are relative to the elevation of the outlet as equalling
100.00'
For alternative proposals, refer to the "Quilcene
Heights, Detention/Release Facility Parameters" chart for
required detention volumes and release rates. Final
approvel of alternative proposals will be by the
Jefferson County Department of Public Works.
717 SOUTH PEABODY, PORT AN{ZELES, WA 98362 (3C:.0) 4~Z-849'~ :'1-{~00..6Di~5 FAX 452-849'8
07/10/97 10:33 ~360 452 $498 NTI ENG.& SURVEY ~004
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07/10/97 10:32 8360 452 8498 NTI ENG,& SL~VEY ~003
07/10/97 10:34 ~360 452 8498 NT! ENG.& SURVEY
07/10/97 10:35 8360 452 8498 NTI ENG.& SURVEY ~006
QUILCENE MEIGHTS
Detention/Release Facility Parameters
Inside Bottom of Tank
Bottom of Sum%p
Or~fice #l
Elevation Orifice #1
Release Rate (CFS)
Outlet Elevation
Orifice ~2
Elevation Orifice #2
Release Rate (CFS)
Orifice #3
Elevation Orifice
Release Rate (CFS)
Max Overflow Elev
Min Overflow Elev
Inside Top of Tank
Volume of Tank
2ooo.. SF[ 3000 SF
99.50'
97.50'
0.38"
99.50'
.01
100.00'
104.40'
.03
0.38"
105.00'
.05
106.00'
105.75'
106.50'
2094 Gal
99.50'
97.50'
0.47"
99.50'
.01
4000 SF
99.50'
97.50'
0.53"
99.50'
.O2
100.00 ' 100.00'
1 . 22" 1 . 45"
104.40'
.04
104.40'
.O6
0,54" 0,53"
105.00' 105-00'
.07 .09
106.00' 10§.00'
105.75'
106.50'
3142 Gal
I05.75'
106.50'
4189 Gal
NOTE:
Elevations are based upon an assumed elevation of 100.00
for the outlet pipe from the detention structure. Ail
other elevations are based upon this datum.
May 9, 1997
Mr. Robert Leach, P.E.
Northwestern Territories, Inc.
717 South Peabody
Port Angeles, WA 98362
Re: Quilcene Heights Long Plat
Dear Mr. Leach:
JEFFtRSON COUNTY
DEPARTMENT OF PUBLIC WORKS
RO. Box 2070
1322 Washington St.
Port Townsend, WA 98368
(360) 385-9160
K/ara A. Fabry, Director/County Engineer
1997
JEFFERSON COUNTY
PERMIT CENTER
This letter is intended to confirm our telephone conversation on April 23, 1997. At that time we
discussed the Drainage Report dated March, 1997 which you prepared for the referenced project.
Based on our conversation I have the following comments:
TEMPORARY EROSION CONTROL
There is an existing logging road on the site that is proposed to provide access to the lots from.-
Mclnnes Road. Reconstruction of this road and installation of utilities requires less than one acre of
land disturbing activity and will create less than 5,000 square feet of impervious surface. The Jefferson
County Stormwater Management Ordinance requires proponents for developments which meet these
criteria to implement a Small Parcel Erosion and Sediment Control Plan that applies the Small Parcel
Minimum Requirements from the Washington Department of Ecology Stormwater Management
Manual. A Small Parcel Erosion and Sediment Control Plan which meets these requirements shall be
submitted to the Jefferson County Department of Public Works for review and approval prior to
commencing land disturbing activity. The Plan should include construction notes and depict the
location and specifications for Best Management Practices.
ACCESS ROAD CONSTRUCTION PLANS
The access road shall be constructed to the following minimum standard: A 20 feet wide unobstructed,
traversable clear zone and 12-14 feet wide traveled way with a minimum 6 inches compacted gravel
base over compacted subgrade, a minimum 2" compacted crushed surfacing top course, and grade not
exceeding 14% without approval from the Department. Road grades greater than 12% shall have an
improved roadway surface, either LBST or asphalt concrete.
!00% Recycled Paper
You have submitted a plan view of the road alignment and a typical roadway section. As per our
conversation, the plan should be revised as follows:
* There should be 4 feet of traversable width at a slope not exceeding 4:1 on both sides of the gravel
surfacing;
* The cul-de-sac legs should be a minimum 30 £eet on each side of Centerline and each leg should a
minimum 20 feet wide; and
* You should verify whether the road grade will be less than 12%.
ACCESS ROAD EASEMENT
A 60 feet wide easement is typically required for the access road. This may be reduced to 40 feet in
width provided that this is adequate to accommodate the road, cut and fill slopes, and utilities.
ACCESS ROAD AND MCINNES ROAD RIGHT-OF-WAY
As per the SubdMsion Ordinance requirements, a 60 feet wide right-of-way for Mclnnes Road (30 feet
on each side of the centerline) shall be dedicated to Jefferson County in fee simple.
We discussed that a portion of the proposed access mad is within this right-of-way. The Department
recognizes that the traffic volume on Mclnnes Road is low and that the land use patterns and area of
undeveloped land that adjoins Mclnnes Road make it unlikely that Mclnnes Road would require
widening. However, it is the Department's responsibility to protect the County's interest by making
appropriate provision for this possibility. In order to meet this responsibility, the Department proposes
the following:
* The access road may be kept on its present alignment, provided that a license to use the right-of-way
is granted by the County. This should be resolved in conjunction with final plat approval by the Board
of Commissioners.
* An easement for the access road shall be established outside of the County right-of-way. The
easement should be located so that the access road can be moved outside of the right-of-way, if this
becomes necessary.
* There shall be a notice on the plat that the access road is constructed on the County right-of-way. It
should state that maintenance work within the right-of-way requires a permit fi.om Jefferson County
and that should it be necessary for Jefferson County to widen Mclnnes Road, the portion of the access
mad within the fight-of-way shall be moved at the lot owners' expense.
I have discussed this matter with County Engineer Klara Fabry. She concurs with this approach.
DETENTION OF RUNOFF FROM RESIDENCES
In order to meet the requirements of the Mitigated Determination of Nonsignificance for the project,
the Drainage Report proposes detention of stormwater runoff fi.om residences by means ofindMdual
detention vaults. The report provides specifications for detention vaults based on the calculations by
NTI. The specifications for the detention vault shall either be depicted on the final plat or be filed with
the Jefferson County Auditor and the Auditor's File Number shown on the final plat. In order to notify
potential purchasers and ensure compliance with the MDNS, the following condition shall be placed on
the plat:
In order to avoid significant adverse impacts related to stormwater mnofffrom the
residences constructed on the Plat of Quilcene Heights, mnofffrom residences and
appurtenant structures shall be directed to a detention or infiltration facility.
Specifications for a detention vault have been designed by a licensed civil engineer.
These specifications have been filed with the Jefferson County Auditor under Auditor's
File Number . Alternative means of detaining or infiltrating
runoff water which equal the standard in these specifications may be used. Detention or
infiltration are not required on Lot 1 provided that runoff water is not directed to the
access road ditch.
If you have any questions or ifI can be of assistance, please don't hesitate to contact me.
~ Sincerely;~'.---------~---~
\
... james W.
Proj'ect Manager
c: Jerry Smith
NORTHWESTERN TERRITORIES, INC.
717 South Peabody Street
PORT ANGELES, WASHINGTON 98362
NTI
Engineers · Land Surveyors · Planners
Construction Coordination · Materials Testing
Phone (360) 452-8491 · Fax (360) 452-8498
TO:
CHRIS SHARP
PAC FIVE, INC.
PO BOX 21447
SEATrLE WA 98111-3477
DATE:
AI-FENTION:
SUBJECT:
March 28, 1997
Drainage Report
WE ARE TRANSMll-I'ING THE FOLLOWING:
Drainage Report
Quilcene Heights Subdivision
Jefferson County, Washington
Prepared for S&S Management
REMARKS:
Transmittal copy to: Jerry Smith, Jefferson County Permit Center
These are: For Your Review
Sent via: U. S. Mail
Copy to:
Signed
Robert A. Leach, P.E., MBA by M. McKay
Padraic Burke
Bomi Khambata,
Jefferson County