0806_001.pdfOCE
OConnell Civil Engineering — 1508 Hoyt Avenue, Everett, WA 98201
Phone: 206-747-3494 email: ojerry26@yahoo.com
April 10, 2019
Jennifer Lambert, Engineering Technician
City of l;tlnlonds, Engineering Division
121 5'h avenue N
Edmonds, WA 98020
RE: Application#: BLDG20181520
Project: Weiss/Cook single family residence at 7412176`h st sw
RE: Response letter to Engineering Division review comments dated 01130119
Dear Jennifer:
Thank you for your review comments. The following revisions have been made to the civil plans in
response to those comments:
General:
1. plans have been updated with the new city standard details.
2. side sewer permit application: to be submitted by the applicant under separate cover.
3. easement AFN's have been added to the plans.
4. driveway slope has been reduced.
a. added note on C3 to reference ECDC 18.80.060 limit of 14% slope.
b. revised contour elevations for clarity
c. maximum driveway slope has been reduced to under 11%.
5. fire/aid address sign: added callout, symbol, & note on c3; added std dtl on c4.
6. retaining wall inside sewer easement: moved wall outside easement since no wording allowing a
structure was found in easement document.
7. added finish grades at front of wall and existing grades at back of wall and the height difference in the
grades; added a callout to explain the grades; added surcharge note as note 43 to construction notes and
added 3' wall height limit callout on c3.
8. for information only
C1 of 4 — cover sheet & swppp notes/details:
La.-c. updated and added more current city standard details
2. added BMP#T5.13 note to swppp construction notes
3. added tesc note to swppp construction notes
4. moved impervious surface chart to c3.
C2 of 4 - swppp & tese plan
1. revised bmp legend to reference sht # and updated std dtl #.
2. revised filter fence to show it on -site only.
3. added filter fence near 176`h st to be downhill from construction
4. filter socks: added note to swppp construction notes; updated detail# in legend.
S. stockpile: added 24hr cover note to callout and to swppp construction notes
6. BMP#T5.13: added note to swppp construction notes.
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OCE
OConnell Civil Engineering — 1508 Hoyt Avenue, Everett, WA 98201
Phone: 206-747-3494 email: ojerry26@yahoo.com
C3 of 4 - site development & storm/utility plan
Water
1 a. added `install P meter' callout.
lb. added callout for water service line size to existing & proposed line.
lc. added pipe material and tracer wire callout.
2. separation comment assumed to be for information only (no change made to plans
3. water/sewer separation: revised to provide 10' separation minimum.
4. no irrigation backflow assembly is proposed.
Sewer
1. proposed side sewer: labeled pipe material, length and size
2. cleanout: added callout on plan and detail sheet reference in legend.
3. added cleanout within 2' of house
4. added invert elevations to enable confirming 2% minimum slope
S. deleted line from cleanout on ex. side sewer; it was an error.
6. added ex. side sewer to be `tv'd' callout. (added box around note)
7. ex. sewer lateral: tv and cleanout note to callout. (added box around note)
8. sewer connecting to water line: added missing manhole & sewer line information to show sewer lateral
connecting to manhole. (they had not been previously shown on plan).
Dig utilities
1. separation comment assumed to be for information only (no change made to plan)
Storm
1. impervious area chart: revised to clearly show what impervious area was added by short plat, (1325sf);
what impervious area is proposed (5765s& 3355sf + 2410sf) and what area will be collected by detention
(7090sf).
2. driveway runoff control: the detention tank has been moved under the new driveway and more of the
existing driveway (580sf) has been replaced: berms at cb's #4, #5, #6 have been added to direct water into
the eb grates. In addition, curbing has been added to portions of the new driveway to better direct runoff.
3a. tank design: WWHM program was rerun to design the tank to account for groundwater and landscape
areas. No change was required to the detention system, since there was only a slight increase in the
controlled release flows (+0.0005cfs) and there was no significant change in the results compared to the
originally accepted tank design.
See the wwhm calculations submitted for the Zackary's review in the stormwater section.
3b. Yard drain/ditch: the pipe from the yard drain is shown connected to the wall/footing drain, which
connects downstream from the detention system at cb#2 which is on the outfall line.
4. easement for detention system: the easement recording number has been included on the plan.
4a. the tank has now been located under the driveway showing 2' minimum cover. (see c3 & detail on c4)
5. the 30" detention tank originally shown per city records was not constructed. An as -built field survey
was done and the actual location has been shown on the plan.
6. footing/wall drain connection: the outfall line has been redesigned and these drains now connect to
cb#2, anew location in the outfall line.
7. type-2 manhole note: was added as note #3 to construction notes.
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OCE
OConnell Civil Engineering — 1508 Hoyt Avenue, Everett, WA 98201
Phone: 206-747-3494 email: ojerry26@yahoo.com
C4 of 4 - notes & details
1 a. changed note # 1 to 2018.
1 b. changed note #21 to updated information (contact person) as requested.
2. replaced std details with current version, added additional details as appropriate.
Stormwater Engineer review comments:
Note to Zackary Richardson
To address Jennifer's storm comment #3a above, wwhm was rerun to account for groundwater and the
landscape areas. The calculations have been submitted for your review. The basin areas changed to
reflect the added landscape areas and increase in replaced driveway area due to relocation of the tank
in the driveway. Pages 0predeveloped, #4-nriti; uted, and #8pocl analysis results, from the
previously submitted report have been included to allow for comparison.
There was only a slight increase in the poc#1 mitigated flows as shown below:
Targets
Revised report
Previous report
2yr cfs
10 r cis
; 100yr cfs
_ _
0.0105
_
�0.0209
_ —
0.0493_
_
0.016529
0.023074
0.032201
0.016067
0.022517 _
_ �0.031547
Increasefrom previous ++0 00462 +0.000557 _ 1 +0.000654_
Previous comparison to targe Over Over Under
_ (+0.0056) (+0.0016) J(-0.01-78)
Revised comparison to target Over Over Under
(+0.0056) (+0.0022) (-0.0171)
Result: cfs increase slight; no change in relation to over/under target
Therefore, no change in the detention tank data was needed
Stormwater Engineer review comments.
1. cl revised lines 2 & 3 on the impervious table (moved from cl to c3) so that line 8 will match gross
total in table above. Added additional information help clarify the areas (per Jennifer's comments)
2. 03 added recording number of existing easement on lot 1 for the detention outfall system.
3. c3 revised pipe inlets to cb# 1 (only one 8"-in and one 12"-out... structural strength should no longer
need to be addressed.
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OCE
OConnell Civil Engineering — 1508 Hoyt Avenue, Everett, WA 98201
Phone: 206-747-3494 email: ojerry26@yahoo.com
4. 0 piping clearance conflicts: no dependable as -built data was found for the existing underground
improvements, their location can only be assumed and potential conflicts field verified during
construction. The following note has been added on c3 where appropriate to alert the contractor:
'existing utility locations in this area are very approximate. Contractor shall
determine as -built data prior to construction and shall `fit -in -field' as needed Design
revisions may be required '
5. c3 driveway runoff control: on c3 the detention tank has been moved under the new driveway and
more of the existing driveway (580sf) has been replaced: berms at cb's #4, #5, #6 have been added to
direct water into the cb grates. In addition, curbing has been added to portions of the new driveway to
better direct runoff.
6. 0 footing/wall drain (solid or perforated): a legend has been added on 0 to clarify solid or perforated
drains; the cad line types have been revised to correspond to the legend. (the previous line type was
chosen not to designate solid or perforated, but to help distinguish the drains from other improvements)
7. c4 detention tank bedding detail: a pipe bedding detail has been added and the detention system detail
has been revised on c4. A note has been added for contractor to obtain detention tank shop drawings from
the manufacturer prior to construction. The wall/ftg drains shown were not intended to be buoyancy
drains for the tank. If tank drains are required it will be at the recommendation of the soils engineer once
the actual subsurface conditions are known during construction.
Planning division: Amber Groll, planner
Comment #4b — walls in setbacks:
The following were added to sheet c3:
-wall height callout
-note about 3' height limitation
(note: the remaining comments to be addressed by others)
Jerry OConnell, P.E. OCE engineering
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