0807_001.pdfOCE
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-mitigated, and #8 pocl 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:
ITargets
Revised report
Previous report
Increase from previous
Previous comparison to target
2yr cfs _—��l0yr cfs — 100yr cfs
0.0105 I0.0209 _ 0.0493_
0.016529 0.023074 _ 0.032201
0.016067 0.022517 _ _ 0.031547 —
+0.00046
Over
(+0.0056)
Revised comparison to target Over
— — — — — — --- — (+0.0056)
2 _ +0.000557 _ T+0.000654_
Over Under
(+0.0016) _ (-0.0178)_
— Over — Under —�
(+0.0022) _ (4.0171)
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 03) so that line 8 will match gross
total in table above. Added additional information help clarify the areas (per Jennifer's comments)
2. c3 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.
1403-Itr-reply 1-bldg
OCE
OConnell Civil Engineering — 1508 Hoyt Avenue, Everett, WA 98201
Phone: 206-747-3494 email: ojerry26@yahoo.com
4. c3 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 0 where appropriate to alert the contractor:
'exisrin�; utility locations in this area are very approximate. Contractor shall
determine as -built data prior to construction and shall `fit -in Feld' as needed Design
revisions may be required'
5. 0 driveway runoff control: on 0 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. c3 footing/wall drain (solid or perforated): a legend has been added on c3 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/flg 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
1403-Itr-reply1-bldg