Comments #2 Sent.pdfCity of Edn"ionds
121 ',5"" VENUE NORI 11 > EDMONDS, WA 98020 - (425)'7'7t,-0220 FAX(425)771-0221
Website:
I
DEVLLOPMI"INTSERVICES DEPARTMENT
Planning - BUildiing - Eiigitieeiliig
Plan. Review, (-,onirnents
Plaiiij Check th BLD20140522 Date- A i List 28, 201/1- ............
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- ............ . . ....... . .
Project Nanw/Address: McGilliv1, - q
.y Addition - 20508 85"' Pl. W
Contact Person/Address/Fax. Terr..Willev I
--con)C,,,ISLrwt
Y. ---------------------------
Reviewer- Chris Rivera Division. E
............ .
During review of the subject submittal, it was found that the following information, corrections, or
clarifications would need to he addressed. All] Handouts referred to in these comments can be accessed at
our website: %vww.e(hrDoiWsWa. jri,),v/, under City Governinent / Development Services Department
Engineering Division then scroll down to Handouts.
SI Review—Juane 26, 2014
2 1 Review — August 28, 2014
5) Please label and show on the site plan square footage and year of construction 1=or all existing impervious
surfaces (gravel areas, walkways, roof line of existing structures, etc.), also label as 'Proposed' or 'To be
Removed' if it applies. Please identify the following and any other impervious surfaces not counted.
a) Curved driveway extension SOLIth of approved driveway (entry to garage).
.b)-,S1+e.c4&-an4--eaMort-iii-the-b-a-ek-yai:d-.
-0+-2
o4-ea-ve-s--�Hi+ed-f 4 -
Please update the impervious surface, Site Classification chart accordingly.
August 28 -- Impervious surfaces do not look consistent behveen a) the existing concrete (please see
attached street view image), b) information provided on the site plan (when measured to scale
totals approx. 385 sf) and the provided impervious amount of 285 sf.
A) Please recalculate/measure existing impervious surface areas and correct numbers witbin the
Stora water Report, site plan and also provide a Site Classification chart from handout
E.-7: (attac lied).
6) laipervious surface areas on your site plan are notconsistent. Rlease numbersa-nd
ARgIripst 28'- Sce con'unetfls 145��w
IDATE FAXED/F-MAILED 8/28/2014 FACE 1 0 P' I
7) Please mote, stormwater mitigation for a lot with over 5,000 sgft total impervious surface needs to be
designed by a registered engineer.
August 28"' — Submitted site plan is not consistent with the submitted Detention System Design Exhibit
within the Detention System Sizing Report provided by Donna L. Breske PE.
- The existing detention system was sized using the old City of Edmonds sizing chart, which required
56' of 18" diameter pipe for an impervious area of 4000 sf (see attached outdated chart) this met
impervious surfaces constructed in 2003 of 3950 sf.
- Requirements have become more stringent, the proposed sizing submitted within the site plan calls
for an additional 56' of 18" diameter pipe to be installed with the existing 56' totaling 112' of 18"
diameter pipe meeting today's requirements for a total of 5000 sf. The submitted site plan is correct
and a correct use of the City of Edmonds Stormwater Detention System Simplified Sizing.
- The Stormwater Detention System Simplified Sizing handout E -72A, shall not be modified, such is
done within the Detention System Sizing Report submitted, pg. 5 - Detention Pipe Sizing Chartper City
of .Edmonds. The report calls out the use of the three catch basins for detention and reduces the
required detention size. This information is transferred to the exhibit Detention Wipe Loeation (pg. 7).
This is a modification of the Simplified Sizing Tabel, which would not be an approved method for
detention sizing.
August 28"' - Conclusion. You have three options, you can;
a) using the City of Edmonds Stormwater Retention System Simplified Sizing Table, withdraw your
storm water report and provide the correct impervious surface areas on your site plan and site
classification chart, assuming you are going to stay under 5000 sf. (the storm water report is not
needed if impervious surfaces are under 5000 sf.) or;
b) using the City of Edmonds Stormwater Detention System Simplified Sizing Table, make sure that
all information provided is consistent within the site plan and storm water report as well as
provide the correct impervious surface areas assuming you are under the 5000 sf, or;
c) provide a Stormwater report with a detention system designed by a licensed engineer not using the
city of Edmonds Simplified Detention system and accounting for all impervious surfaces, including
providing the correct impervious surface areas on a submitted site plan.
1151i �;.MNKMZMM
Please resubmit 3 copies of the revised plans/documents to a Development Services Coordinator.
Please contact me at 425-771-0220 if you have specific questions regarding these plan corrections.
®ATE FAXED/E-MAILED 8/28/2014 PAGE 1 OF t
TADI E I - DEI'l1'\ffiffiNI F%31- S0"S
lk4FlFHMlE/'),BLE
MAX. SIZE
�,h,CATCH
PIPE
DA�",Al-TER
I<NOCi<OUT--..,...-,--
AREA SO 17-T
VO[,,. CLJ
5
20
... .. . ..... 2zI,
30"
2000
50
40
28
16
-10
2500
62
50
35
20
'13
3000
75
60
42
24-
'15 REQUIRED FlPE
3500
87
/0
49
28
is I -ENG -1E-1 IN FEET
/1000
'100
80
6
32
2-1
4500
112
90
63
36
23
5000
125
100
70
do
25
NOIE: ALLOWABLE PIFE k4AfERIA1...S
REINT-ORCED CONCRETE—
ALUIAHZED STEEL
ALUMINUM (16GA)
CMP (ASPHALT COATED)
N-12 ADS (2' MHMUM COVER UNDER R
ALLOWABI...E'" 11(31-111NE k/iATERIALS
SDR35 (ASTM D-3034) PVC
NI -12 ADS (DOUBLE WALLED)
SCHED 4-0 PVC
FIANCOR (F810) PVC
/DRIVEWAYS)
LB IBLE 2— OUTLET ORIFICE SIZES J
IM,PERVIOUS OUTLET ORIFICE DIAMETER (INCHES)
AR EA SQ. rr
2000 5/8
2500 5/8
3000 f,, 3/4
3500/ 3/4
400p, 7/8
45aO 7/8
50,60 7/8
TABLE 3— F' ECTANGULAR CATCH BASIN REQUIREMENTS
DL TENTION '/
MAX. SIZE
�,h,CATCH
BASIN
PIPE DIAMETER
I<NOCi<OUT--..,...-,--
TYPE
<..1
20
TYPE 1,
C8 15
'18" TO 2,4"
26"
TYPE ll-,
CB 16
24" TO 36"
36"
TYPE 11,
CB 19 (48" BASIN)
36" TO 42"
42"
TYPE 11,
CB 19 54" BASIN)
**SOUI-RCE-. ASSOC. SAND AND GRAVEL CO. ST'DS.
0
c
.......... . ..... . . .. . ... .. . ....... . ........ . .......... .
0
("""ity 01"" Edr"T-iurids
Site \A/orksl��ieet
D age J. o f 2
Tlie project's Site Chqssificaticn will clictate tile specific slorillwater nianagement
requirements applicable to your site. Cornpleting this worksheet will help deLennine fl'ie altIOLIVA Of
I-egUlated imperviolls stirface and whether your project falls into tine classification ol"a Small She
(Category I or Category 2), or a Minor Site, Pieise reference (lie Glossa1y-0211.___LQ--J I JJ:,igures D and
L.1 -am.– 1 1 - –12),. -Lo assist with coni pleti on of this worksticet.
7711""Fel"m, . ...... . e ............ a 'b"Te'—Pave–n—ke—ntl —Prop" —osed Fo'R7 -Use on —fll'ds —Site?
Refer to Stot-iiiti)atei-,S'ili)i)leiiienI Chotner 5,1 0 Yes E.'.] No
If YES, the subject area is to be considered iniperviotis for initial site classification purposes, Include vital
permeable pavement area in the calcitlation of torr-Re(ullated, Iepjaqecl and/or NeN 11-11perviot-Is S1111"Ice
areas in the table below.
.. . . . ......... . . ........... . . ...... 7--'
Deterinine the Amount and Type of Existing & Proposed Imperuu
vios Srface for the SiFe
Reftr to Storinivater Suppler lent Chapter 2 and Fig, C
.... ......... .
Line 1! Identify the Non -Regulated Impervious Surface A, rea,
Une 2: identify the Replaced Tonpervious Surface Area, dividing the total between J.,,xe n)t and R oulated, either or both
ruay be, zero. Note: or I)ro ' ject classification purposes,, ReplaI
ced nipervioual
s ay only be considered c.xci-nl-)t
Under certain conditions, Refer to the Glossary and Figure D.
Line 3� Identif
y the New Impervious Surface Area for your In'oject. All inipervious areas created post -July 7, 1977 or
after the date of annexation into the City are regulated & should be included in this total unless they can be
categori70d scilarately as a Replaced -Regulated area.
Line 4: Enter the sunt of the total Replaced -Regulated plus the total New impervious areas.
Line 5: Identify the total area currently mitigated by all existing city -approved storrilwater rnatiagenient system,L,
Line 6: Enter the surn of the value in Line 4 less tile Value in Line 5 to identify the total Regulated arca in which
storinwater controls have not yet been applied,
Line 7: Identify the total area proposed to be nlitigatod through the use of l -,ow Tinpact Devc1opi-neriL Techniques.
Line 8: Identify the total area proposed to be mitigated through conventional Stormwater Management Techniques.
41 L"
Provide a copy of the following table on the drainage plan sheet for the proposed project s.
INNHINUI
Line Type Area (square feet)
1. Non-regulated
Exempt
Regulated
F
2. Replaced
........... .......
3. New (Post 1977) 4 4 4 4 4
4. Total Regulated Impervious Area
ad late alion required if in excess qf'2000.cf
5. Total Area Mitigated by Existing Stornma(er Mai agement System(s)
— - - --------------- - —
6, RegWated Area Not Yet Mitigated
. ......... ..
7. Area
- -------- -
8, Area I'voposed to he Mftigated thro"glh Conventional S 1
Prof] msed to lie Nutig"'Ited lby Low Impact Development Techni
............ . . . . . . . . . . . . . . . . ........... ................
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